Anti-inflammatory and analgesic properties of Polyphyllin VI revealed by network pharmacology and RNA sequencing - Zhenglang Zhang; Tingting Wang; Zhenhui Luo; Muhammad Haris Zaib; Mengqin Yi; Hekun Zeng; Peiyang Li; Dan Tang; Alexei Verkhratsky; Hong Nie (Purinergic Signalling, 2024)

Synthesis of new non-natural l-glycosidic flavonoid derivatives and their evaluation as inhibitors of Trypanosoma cruzi ecto-nucleoside triphosphate diphosphohydrolase 1 (TcNTPDase1) - Isadora Cunha Ribeiro; João Victor Badaró de Moraes; Christiane Mariotini-Moura; Marcelo Depolo Polêto; Nancy da Rocha Torres Pavione; Raissa Barbosa de Castro; Izabel Luzia Miranda; Suélen Karine Sartori; Kryssia Lohayne Santos Alves; Gustavo Costa Bressan; Raphael de Souza Vasconcellos; José Roberto Meyer-Fernandes; et al. (Purinergic Signalling, 2024)

Modafinil exerts anti-inflammatory and anti-fibrotic effects by upregulating adenosine A2A and A2B receptors - Haiyan Li; Ji Aee Kim; Seong-Eun Jo; Huisu Lee; Kwan-Chang Kim; Shinkyu Choi; Suk Hyo Suh (Purinergic Signalling, 2024)

P2 X 7 receptor is a critical regulator of extracellular ATP-induced profibrotic genes expression in rat kidney: implication of transforming growth factor-β/Smad signaling pathway - Fatma Mounieb; Somaia A Abdel-Sattar; Amany Balah; El-Sayed Akool (Purinergic Signalling, 2024)
This study was designed to investigate the potential of extracellular adenosine 5′-triphosphate (ATP) via the P2 X 7 receptor to activate the renal fibrotic processes in rats. The present study demonstrates that administration of ATP rapidly activated transforming growth factor-β (TGF-β) to induce phosphorylation of Smad-2/3. Renal connective tissue growth factor (CTGF) and tissue inhibitor of metalloproteinase-1 (TIMP-1) mRNA and protein expressions were also increased following ATP administration. A decrease in TGF-β amount in serum as well as renal Smad-2/3 phosphorylation was noticed in animals pre-treated with the specific antagonist of P2 X 7 receptor, A 438,079. In addition, a significant reduction in mRNA and protein expression of CTGF and TIMP-1were also observed in the kidneys of those animals. Collectively, the current findings demonstrate that ATP has the ability to augment TGF-β-mediated Smad-2/3 phosphorylation and enhance the expression of the pro-fibrotic genes, CTGF and TIMP-1, an effect that is largely mediated via P2 X 7 receptor.

Pharmacological interaction and immune response of purinergic receptors in therapeutic modulation - Seyed Hossein Kiaie; Zahra Hatami; Mohammad Sadegh Nasr; Pouya Pazooki; Salar Hemmati; Behzad Baradaran; Hadi Valizadeh (Purinergic Signalling, 2024)

Caffeine reduces viability, induces apoptosis, inhibits migration and modulates the CD39/CD73 axis in metastatic cutaneous melanoma cells - Daiane Manica; Gilnei Bruno da Silva; Jussara de Lima; Joana Cassol; Paula Dallagnol; Rafael Antônio Narzetti; Marcelo Moreno; Margarete Dulce Bagatini (Purinergic Signalling, 2024)

Hippocampal astrocytes relieve anxiogenic behavior by increasing, via the release of ATP, excitatory synaptic transmission in dentate gyrus granule cells - Meng-Juan Sun; Yong Tang; Peter Illes (Purinergic Signalling, 2024)

Tumoral P2Y2 receptor modulates tumor growth and host anti-tumor immune responses in a syngeneic murine model of oral cancer - Kevin Muñoz Forti; Lucas T. Woods; Kimberly J. Jasmer; Jean M. Camden; Gary A. Weisman (Purinergic Signalling, 2024)

The role of pyruvate-induced enhancement of oxygen metabolism in extracellular purinergic signaling in the post-cardiac arrest rat model - Koichiro Shinozaki; Vanessa Wong; Tomoaki Aoki; Kei Hayashida; Ryosuke Takegawa; Yusuke Endo; Harshal Nandurkar; Betty Diamond; Simon C. Robson; Lance B. Becker (Purinergic Signalling, 2024)

Correction to: A1R–A2AR heteromers coupled to Gs and Gi/0 proteins modulate GABA transport into astrocytes - Sofia Cristóvão-Ferreira; Gemma Navarro; Marc Brugarolas; Kamil Pérez-Capote; Sandra H. Vaz; Giorgia Fattorini; Fiorenzo Conti; Carmen Lluis; Joaquim A. Ribeiro; Peter J. McCormick; Vicent Casadó; Rafael Franco; et al. (Purinergic Signalling, 2024)

Correction to: Regulation of TrkB receptor translocation to lipid rafts by adenosine A2A receptors and its functional implications for BDNF-induced regulation of synaptic plasticity - Natália Assaife-Lopes; Vasco C. Sousa; Daniela B. Pereira; Joaquim A. Ribeiro; Ana M. Sebastião (Purinergic Signalling, 2024)

Correction to: P2 purinergic receptors regulate the progression of colorectal cancer - Wen‑jun Zhang; Li‑peng Zhang; Si‑jian Lin; Cheng‑yi Wang; Yi-guan Le (Purinergic Signalling, 2024)

P2X7 receptors and pannexin1 hemichannels shape presynaptic transmission - Nathalia Vitureira; Alberto Rafael; Verónica Abudara (Purinergic Signalling, 2024)

Functional expression of the ATP-gated P2X7 receptor in human iPSC-derived astrocytes - Jaideep Kesavan; Orla Watters; Laura de Diego-Garcia; Aida Menéndez Méndez; Mariana Alves; Klaus Dinkel; Michael Hamacher; Jochen H. M. Prehn; David C. Henshall; Tobias Engel (Purinergic Signalling, 2024)
Activation of the ATP-gated P2X7 receptor (P2X7R), implicated in numerous diseases of the brain, can trigger diverse responses such as the release of pro-inflammatory cytokines, modulation of neurotransmission, cell proliferation or cell death. However, despite the known species-specific differences in its pharmacological properties, to date, most functional studies on P2X7R responses have been analyzed in cells from rodents or immortalised cell lines. To assess the endogenous and functional expression of P2X7Rs in human astrocytes, we differentiated human-induced pluripotent stem cells (hiPSCs) into GFAP and S100 β-expressing astrocytes. Immunostaining revealed prominent punctate P2X7R staining. P2X7R protein expression was also confirmed by Western blot. Importantly, stimulation with the potent non-selective P2X7R agonist 2′,3′-O-(benzoyl-4-benzoyl)-adenosine 5′- triphosphate (BzATP) or endogenous agonist ATP induced robust calcium rises in hiPSC-derived astrocytes which were blocked by the selective P2X7R antagonists AFC-5128 or JNJ-47965567. Our findings provide evidence for the functional expression of P2X7Rs in hiPSC-derived astrocytes and support their in vitro utility in investigating the role of the P2X7R and drug screening in disorders of the central nervous system (CNS).

ADP as a novel stimulus for NLRP3-inflammasome activation in mice fails to translate to humans - Julius Wissemann; Adrian Heidenreich; Helene Zimmermann; Juliane Engelmann; Jasper Jansen; Dymphie Suchanek; Dirk Westermann; Dennis Wolf; Peter Stachon; Julian Merz (Purinergic Signalling, 2024)
The NLRP3-inflammasome is a cytosolic multiprotein complex that triggers an inflammatory response to certain danger signals. Recently adenosine diphosphate (ADP) was found to activate the NLRP3-inflammasome in murine macrophages via the P2Y 1 receptor. Blockade of this signaling pathway reduced disease severity in a murine colitis-model. However, the role of the ADP/P2Y 1 -axis has not yet been studied in humans. This present study confirmed ADP-dependent NLRP3-inflammasome activation in murine macrophages, but found no evidence for a role of ADP in inflammasome activation in humans. We investigated the THP1 cell line as well as primary monocytes and further looked at macrophages. Although all cells express the three human ADP-receptors P2Y 1 , P2Y 12 and P2Y 13 , independent of priming, neither increased ASC-speck formation could be detected with flow cytometry nor additional IL-1β release be found in the culture supernatant of ADP stimulated cells. We now show for the first time that the responsiveness of monocytes and macrophages to ADP as well as the regulation of its purinergic receptors is very much dependent on the species. Therefore the signaling pathway found to contribute to colitis in mice is likely not applicable to humans.

ENTPD1 (CD39) and NT5E (CD73) expression in human glioblastoma: an in silico analysis - Elizandra Braganhol; Guilherme Pamplona Bueno de Andrade; Guilherme Tomasi Santos; Marco Antônio Stefani (Purinergic Signalling, 2024)

Physical exercise as a modulator of the purinergic system in the control of sarcopenia in individuals with chronic kidney disease on hemodialysis - Débora Tavares de Resende e Silva; Matheus Ribeiro Bizuti; Natan Rodrigues de Oliveira; Lucas Zannini Medeiros Lima; Victória Galletti dos Santos Arraes; Ana Carolina Gonçalves Zietz; Carolina Zin; Guilherme Vinício de Sousa Silva; Josiano Guilherme Puhle; Fabiana Brum Haag (Purinergic Signalling, 2024)

Adenosine A2A receptor-bearing GABAergic neurons in the lateral septum of the brain: novel mediators of depressive-like behavior - Ya-Fei Zhao; Peter Illes (Purinergic Signalling, 2024)

Potential role of the P2X7 receptor in the proliferation of human diffused large B-cell lymphoma - Xiao Yang; Yuanyuan Ji; Lin Mei; Wenwen Jing; Xin Yang; Qianwei Liu (Purinergic Signalling, 2024)

Identifiability of enzyme kinetic parameters in substrate competition: a case study of CD39/NTPDase1 - Anna N. McGuinness; Aman Tahir; Nadia R. Sutton; Andrew D. Marquis (Purinergic Signalling, 2024)

Feedback facilitation by adenosine A2A receptors of ATP release from mouse hippocampal nerve terminals - Francisco Q. Gonçalves; Pedro Valada; Marco Matos; Rodrigo A. Cunha; Angelo R. Tomé (Purinergic Signalling, 2024)
The adenosine modulation system is mostly composed by inhibitory A 1 receptors (A 1 R) and the less abundant facilitatory A 2A receptors (A 2A R), the latter selectively engaged at high frequency stimulation associated with synaptic plasticity processes in the hippocampus. A 2A R are activated by adenosine originated from extracellular ATP through ecto-5’-nucleotidase or CD73-mediated catabolism. Using hippocampal synaptosomes, we now investigated how adenosine receptors modulate the synaptic release of ATP. The A 2A R agonist CGS21680 (10-100 nM) enhanced the K + -evoked release of ATP, whereas both SCH58261 and the CD73 inhibitor α,β-methylene ADP (100 μM) decreased ATP release; all these effects were abolished in forebrain A 2A R knockout mice. The A 1 R agonist CPA (10-100 nM) inhibited ATP release, whereas the A 1 R antagonist DPCPX (100 nM) was devoid of effects. The presence of SCH58261 potentiated CPA-mediated ATP release and uncovered a facilitatory effect of DPCPX. Overall, these findings indicate that ATP release is predominantly controlled by A 2A R, which are involved in an apparent feedback loop of A 2A R-mediated increased ATP release together with dampening of A 1 R-mediated inhibition. This study is a tribute to María Teresa Miras-Portugal.

Gene regulation in activated microglia by adenosine A3 receptor agonists: a transcriptomics study - Alejandro Lillo; Joan Serrano-Marín; Jaume Lillo; Iu Raïch; Gemma Navarro; Rafael Franco (Purinergic Signalling, 2024)
Most neurodegenerative disorders, including the two most common, Alzheimer’s disease (AD) and Parkinson’s disease (AD), course with activation of microglia, the resident innate immune cells of the central nervous system. A 3 adenosine receptor (A 3 R) agonists have been proposed to be neuroprotective by regulating the phenotype of activated microglia. RNAseq was performed using samples isolated from lipopolysaccharide/interferon-γ activated microglia treated with 2-Cl-IB-MECA, a selective A 3 R agonist. The results showed that the number of negatively regulated genes in the presence of 2-Cl-IB-MECA was greater than the number of positively regulated genes. Gene ontology enrichment analysis showed regulation of genes participating in several cell processes, including those involved in immune-related events. Analysis of known and predicted protein-protein interactions showed that Smad3 and Sp1 are transcription factors whose genes are regulated by A 3 R activation. Under the conditions of cell activation and agonist treatment regimen, 2-Cl-IB-MECA did not lead to any tendency to favor the expression of genes related to neuroprotective microglia (M2).

Preface to special issue “A tribute to Maria Teresa Miras-Portugal” - Esmerilda Garcia Delicado; Herbert Zimmermann (Purinergic Signalling, 2024)

DUSP1/MKP-1 represents another piece in the P2X7R intracellular signaling puzzle in cerebellar cells: our last journey with Mª Teresa along the purinergic pathways of Eden - Juan Carlos Gil-Redondo; María José Queipo; Yaiza Trueba; Celia Llorente-Sáez; Julia Serrano; Felipe Ortega; Rosa Gómez-Villafuertes; Raquel Pérez-Sen; Esmerilda G. Delicado (Purinergic Signalling, 2024)
The P2X7 receptor (P2X7R) stands out within the purinergic family as it has exclusive pharmacological and regulatory features, and it fulfills distinct roles depending on the type of stimulation and cellular environment. Tonic activation of P2X7R promotes cell proliferation, whereas sustained activation is associated with cell death. Yet strikingly, prolonged P2X7R activation in rat cerebellar granule neurons and astrocytes does not affect cell survival. The intracellular pathways activated by P2X7Rs involve proteins like MAPKs, ERK1/2 and p38, and interactions with growth factor receptors could explain their behavior in populations of rat cerebellar cells. In this study, we set out to characterize the intracellular mechanisms through which P2X7Rs and Trk receptors, EGFR (epidermal growth factor receptor) and BDNFR (brain-derived neurotrophic factor receptor), regulate the dual-specificity phosphatase DUSP1. In cerebellar astrocytes, the regulation of DUSP1 expression by P2X7R depends on ERK and p38 activation. EGFR stimulation can also induce DUSP1 expression, albeit less strongly than P2X7R. Conversely, EGF was virtually ineffective in regulating DUSP1 in granule neurons, a cell type in which BDNF is the main regulator of DUSP1 expression and P2X7R only induces a mild response. Indeed, the regulation of DUSP1 elicited by BDNF reflects the balance between both transcriptional and post-transcriptional mechanisms. Importantly, when the regulation of DUSP1 expression is compromised, the viability of both astrocytes and neurons is impaired, suggesting this phosphatase is essential to maintain proper cell cytoarchitecture and functioning.

Pharmacological characterization of P2Y receptor subtypes – an update - Ivar von Kügelgen (Purinergic Signalling, 2024)
P2Y receptors are G-protein-coupled receptors (GPCRs) for extracellular nucleotides. There are eight mammalian P2Y receptor subtypes (P2Y 1 , P2Y 2 , P2Y 4 , P2Y 6 , P2Y 11 , P2Y 12 , P2Y 13 , and P2Y 14 ). The widely expressed P2Y receptors play important roles in physiology and pathophysiology. This review summarizes the use of pharmacological tools to characterize the P2Y receptor subtypes involved in these responses. MRS2500 is a potent and selective antagonist acting at the P2Y 1 receptor. AR-C118925 is useful for the selective antagonism of the P2Y 2 receptor. PSB16133 blocks the P2Y 4 receptor, MRS2578 is an antagonist at the P2Y 6 receptor and NF157 as well as NF340 block the P2Y 11 receptor. ADP-induced platelet aggregation is mediated by P2Y 1 and P2Y 12 receptors. A number of compounds or their active metabolites reduce ADP-induced platelet aggregation by blocking the P2Y 12 receptor. These include the active metabolites of the thienopyridine compounds clopidogrel and prasugrel, the nucleoside analogue ticagrelor and the nucleotide analogue cangrelor. PSB0739 is also a potent antagonist at the P2Y 12 receptor useful for both in vitro and in vivo studies. MRS2211 and MRS2603 inhibit P2Y 13 mediated responses. PPTN is a very potent antagonist at the P2Y 14 receptor.

Effect of chronic maternal L-Glu intake during gestation and/or lactation on oxidative stress markers, AMPA Glu1 receptor and adenosine A1 signalling pathway from foetal and neonatal cerebellum - Adrián Tejero; David Agustín León-Navarro; Mairena Martín (Purinergic Signalling, 2024)

Kinetic profiling of novel spirobenzo-oxazinepiperidinone derivatives as equilibrative nucleoside transporter 1 inhibitors - Anna Vlachodimou; Jara Bouma; Michel De Cleyn; Didier Berthelot; Stefan Pype; Jean-Paul Bosmans; Herman van Vlijmen; Berthold Wroblowski; Laura H. Heitman; Adriaan P. IJzerman (Purinergic Signalling, 2024)
Evaluation of kinetic parameters of drug-target binding, k on , k off , and residence time (RT), in addition to the traditional in vitro parameter of affinity is receiving increasing attention in the early stages of drug discovery. Target binding kinetics emerges as a meaningful concept for the evaluation of a ligand’s duration of action and more generally drug efficacy and safety. We report the biological evaluation of a novel series of spirobenzo-oxazinepiperidinone derivatives as inhibitors of the human equilibrative nucleoside transporter 1 (hENT1, SLC29A1). The compounds were evaluated in radioligand binding experiments, i.e. , displacement, competition association, and washout assays, to evaluate their affinity and binding kinetic parameters. We also linked these pharmacological parameters to the compounds’ chemical characteristics, and learned that separate moieties of the molecules governed target affinity and binding kinetics. Among the 29 compounds tested, 28 stood out with high affinity and a long residence time of 87 min. These findings reveal the importance of supplementing affinity data with binding kinetics at transport proteins such as hENT1.

Blockage of the adenosine A2B receptor prevents cardiac fibroblasts overgrowth in rats with pulmonary arterial hypertension - Mafalda Bessa-Gonçalves; Bruno Bragança; Eduardo Martins-Dias; Adriana Vinhas; Mariana Certal; Tânia Rodrigues; Fátima Ferreirinha; Maria Adelina Costa; Paulo Correia-de-Sá; Ana Patrícia Fontes-Sousa (Purinergic Signalling, 2024)
Sustained pressure overload and fibrosis of the right ventricle (RV) are the leading causes of mortality in pulmonary arterial hypertension (PAH). Although the role of adenosine in PAH has been attributed to the control of pulmonary vascular tone, cardiac reserve, and inflammatory processes, the involvement of the nucleoside in RV remodelling remains poorly understood. Conflicting results exist on targeting the low-affinity adenosine A 2B receptor (A 2B AR) for the treatment of PAH mostly because it displays dual roles in acute vs. chronic lung diseases. Herein, we investigated the role of the A 2B AR in the viability/proliferation and collagen production by cardiac fibroblasts (CFs) isolated from RVs of rats with monocrotaline (MCT)-induced PAH. CFs from MCT-treated rats display higher cell viability/proliferation capacity and overexpress A 2B AR compared to the cells from healthy littermates. The enzymatically stable adenosine analogue, 5′- N -ethylcarboxamidoadenosine (NECA, 1–30 μM), concentration-dependently increased growth, and type I collagen production by CFs originated from control and PAH rats, but its effects were more prominent in cells from rats with PAH. Blockage of the A 2B AR with PSB603 (100 nM), but not of the A 2A AR with SCH442416 (100 nM), attenuated the proliferative effect of NECA in CFs from PAH rats. The A 2A AR agonist, CGS21680 (3 and 10 nM), was virtually devoid of effect. Overall, data suggest that adenosine signalling via A 2B AR may contribute to RV overgrowth secondary to PAH. Therefore, blockage of the A 2A AR may be a valuable therapeutic alternative to mitigate cardiac remodelling and prevent right heart failure in PAH patients.

Diadenosine pentaphosphate regulates dendrite growth and number in cultured hippocampal neurons - M. Diez-Zaera; A. Ruiz-Calvo; J. I. Diaz-Hernandez; A. Sebastián-Serrano; P. Aivar; B. Alvarez-Castelao; J. Pintor; M. Diaz-Hernandez; M. T. Miras-Portugal (Purinergic Signalling, 2024)
During the establishment of neuronal circuits, axons and dendrites grow and branch to establish specific synaptic connections. This complex process is highly regulated by positive and negative extracellular cues guiding the axons and dendrites. Our group was pioneer in describing that one of these signals are the extracellular purines. We found that extracellular ATP, through its selective ionotropic P2X7 receptor (P2X7R), negatively regulates axonal growth and branching. Here, we evaluate if other purinergic compounds, such as the diadenosine pentaphosphate (Ap 5 A), may module the dynamics of dendritic or axonal growth and branching in cultured hippocampal neurons. Our results show that Ap 5 A negatively modulates the dendrite’s growth and number by inducing transient intracellular calcium increases in the dendrites’ growth cone. Interestingly, phenol red, commonly used as a pH indicator in culture media, also blocks the P2X1 receptors, avoided the negative modulation of Ap 5 A on dendrites. Subsequent pharmacological studies using a battery of selective P2X1R antagonists confirmed the involvement of this subunit. In agreement with pharmacological studies, P2X1R overexpression caused a similar reduction in dendritic length and number as that induced by Ap 5 A. This effect was reverted when neurons were co-transfected with the vector expressing the interference RNA for P2X1R. Despite small hairpin RNAs reverting the reduction in the number of dendrites caused by Ap 5 A, it did not avoid the dendritic length decrease induced by the polyphosphate, suggesting, therefore, the involvement of a heteromeric P2X receptor. Our results are indicating that Ap 5 A exerts a negative influence on dendritic growth.

Crosstalk between P2Y receptors and cyclooxygenase activity in inflammation and tissue repair - Adrián Povo-Retana; Sergio Sánchez-García; Carlota Alvarez-Lucena; Rodrigo Landauro-Vera; Patricia Prieto; Carmen Delgado; Paloma Martín-Sanz; Lisardo Boscá (Purinergic Signalling, 2024)
The role of extracellular nucleotides as modulators of inflammation and cell stress is well established. One of the main actions of these molecules is mediated by the activation of purinergic receptors (P2) of the plasma membrane. P2 receptors can be classified according to two different structural families: P2X ionotropic ion channel receptors, and P2Y metabotropic G protein-coupled receptors. During inflammation, damaged cells release nucleotides and purinergic signaling occurs along the temporal pattern of the synthesis of pro-inflammatory and pro-resolving mediators by myeloid and lymphoid cells. In macrophages under pro-inflammatory conditions, the expression and activity of cyclooxygenase 2 significantly increases and enhances the circulating levels of prostaglandin E 2 (PGE 2 ), which exerts its effects both through specific plasma membrane receptors (EP1-EP4) and by activation of intracellular targets. Here we review the mechanisms involved in the crosstalk between PGE 2 and P2Y receptors on macrophages, which is dependent on several isoforms of protein kinase C and protein kinase D1. Due to this crosstalk, a P2Y-dependent increase in calcium is blunted by PGE 2 whereas, under these conditions, macrophages exhibit reduced migratory capacity along with enhanced phagocytosis, which contributes to the modulation of the inflammatory response and tissue repair.

María Teresa Miras Portugal: a pioneer in the study of purinoceptors in chromaffin cells - Antonio R. Artalejo; Marina Arribas-Blázquez; María Victoria Barahona; Celia Llorente-Sáez; Luis Alcides Olivos-Oré (Purinergic Signalling, 2024)
María Teresa Miras Portugal devoted most of her scientific life to the study of purinergic signalling. In an important part of her work, she used a model system: the chromaffin cells of the adrenal medulla. It was in these cells that she identified diadenosine polyphosphates, from which she proceeded to the study of adrenomedullary purinome: nucleotide synthesis and degradation, adenosine transport, nucleotide uptake into chromaffin granules, exocytotic release of nucleotides and autocrine regulation of chromaffin cell function via purinoceptors. This short review will focus on the current state of knowledge of the purinoceptors of adrenal chromaffin cells, a subject to which María Teresa made seminal contributions and which she continued to study until the end of her scientific life.

Differently expression of the metabotropic P2Y receptor family after hypoxia-induced seizures in neonates and seizure suppression via P2Y1 receptor agonism - Jonathon Smith; Beatriz Gil Lopez-Avila; Tobias Engel; Eva M. Jimenez Mateos; Mariana Alves (Purinergic Signalling, 2024)

María Teresa Miras Portugal: a pioneer for vesicular nucleotide storage - Yoshinori Moriyama; Nao Hasuzawa; Masatoshi Nomura (Purinergic Signalling, 2024)

Some reflections after a long life in science - Bertil B. Fredholm (Purinergic Signalling, 2024)

Coffee, adenosine, and the liver - Jonathan A. Dranoff (Purinergic Signalling, 2024)

Purinergic P2X3 receptors in the carotid body as new therapeutic targets for controlling heart failure - Ximeng He; Zhichao Zhou (Purinergic Signalling, 2024)
Heart failure is associated with multiple mechanisms, including sympatho-excitation, and is one of the leading causes of death worldwide. Enhanced carotid body chemoreflex function is strongly related to excessive sympathetic nerve activity and sleep-disordered breathing in heart failure. How to reduce the excitability of the carotid body is still scientifically challenging. Both clinical and experimental evidence have suggested that targeting purinergic receptors is of great potential to combat heart failure. In a recent study, Lataro et al. (Lataro et al. in Nat Commun 14:1725, 5) demonstrated that targeting purinergic P2X 3 receptors in the carotid body attenuates the progression of heart failure. Using a series of molecular, biochemical, and functional assays, the authors observed that the carotid body generates spontaneous, episodic burst discharges coincident with the onset of disordered breathing in male rats with heart failure, which was generated by ligating the left anterior descending coronary artery. Moreover, P2X 3 receptor expression was found to be upregulated in the petrosal ganglion chemoreceptive neurons of rats with heart failure. Of particular note, treatment with a P2X 3 antagonist rescued pathological breathing disturbances, abolished episodic discharges, reinstated autonomic balance, attenuated cardiac dysfunction, and reduced the immune cell response and plasma cytokine levels in those rats.

Fetal bovine serum contains biologically available ATP - Valentina Vultaggio-Poma; Leticia Scussel Bergamin; Simonetta Falzoni; Mario Tarantini; Anna Lisa Giuliani; Dorianna Sandonà; Patrizia Polverino De Laureto; Francesco Di Virgilio (Purinergic Signalling, 2024)
ATP is a ubiquitous extracellular messenger released in a wide number of pathophysiological conditions. ATP is known to be present in minute amounts in the extracellular space in healthy tissues and in the blood, and to modulate a multiplicity of cell responses. Cell culture systems are widely used to explore purinergic signaling. We show here that currently used fetal bovine sera contain ATP in the 300–1300 pmol/L range. Serum ATP is associated with albumin as well as with microparticle/microvesicle fraction. Serum microparticles/microvesicles affect in vitro cell responses due to their content of miRNAs, growth factors, and other bioactive molecules. ATP is likely to be one of these bioactive factors found in a variable amount in sera of different commercial sources. ATP in serum supports ATP-dependent biochemical reactions such as the hexokinase-dependent phosphorylation of glucose to glucose 6-phosphate, and affects purinergic signaling. These findings show that cells growing in vitro in serum-supplemented media are exposed to varying levels of extracellular ATP, and thus to varying degrees of purinergic stimulation.

The P2X7 receptor in mucosal adaptive immunity - Fabio Grassi; Rebecca Marino (Purinergic Signalling, 2024)
The P2X7 receptor (P2X7R) is a widely distributed cation channel activated by extracellular ATP (eATP) with exclusive peculiarities with respect to other P2XRs. In recent years, P2X7R has been shown to regulate the adaptive immune response by conditioning T cell signaling and activation as well as polarization, lineage stability, cell death, and function in tissues. Here we revise experimental observations in this field, with a focus on adaptive immunity at mucosal sites, particularly in the gut, where eATP is hypothesized to act in the reciprocal conditioning of the host immune system and commensal microbiota to promote mutualism. The importance of P2X7R activity in the intestine is consistent with the transcriptional upregulation of P2xr7 gene by retinoic acid, a metabolite playing a key role in mucosal immunity. We emphasize the function of the eATP/P2X7R axis in controlling T follicular helper (Tfh) cell in the gut-associated lymphoid tissue (GALT) and, consequently, T-dependent secretory IgA (SIgA), with a focus on high-affinity SIgA-mediated protection from enteropathogens and shaping of a beneficial microbiota for the host.

Human plasmacytoid dendritic cells express the functional purinergic halo (CD39/CD73) - S. A. Sosa-Luis; W. J. Ríos-Ríos; A. Almaraz-Arreortua; M. A. Romero-Tlalolini; S. R. Aguilar-Ruiz; R. Valle-Ríos; C. Sánchez-Torres; H. Torres-Aguilar (Purinergic Signalling, 2024)

Ginsenosides enhance P2X7-dependent cytokine secretion from LPS-primed rodent macrophages - Kshitija Dhuna; Ray Helliwell; Simone N. De Luca; Sarah J. Spencer; Leanne Stokes (Purinergic Signalling, 2024)
The activation of P2X7 is a well-known stimulus for the NLRP3-caspase 1 inflammasome and subsequent rapid IL-1β secretion from monocytes and macrophages. Here we show that positive allosteric modulators of P2X7, ginsenosides, can enhance the release of three important cytokines, IL-1β, IL-6 and TNF-α from LPS-primed rodent macrophages using the J774 mouse macrophage cell line and primary rat peritoneal macrophages. We compared the immediate P2X7 responses in un-primed and LPS-primed macrophages and found no difference in calcium response amplitude or kinetics. These results suggest that under inflammatory conditions positive allosteric modulators are capable of increasing cytokine secretion at lower concentrations of ATP, thus boosting the initial pro-inflammatory signal. This may be important in the control of intracellular infections.

Covalently Binding Adenosine A3 Receptor Agonist ICBM Irreversibly Reduces Voltage-Gated Ca2+ Currents in Dorsal Root Ganglion Neurons - Federica Cherchi; Martina Venturini; Giada Magni; Mirko Scortichini; Kenneth A. Jacobson; Anna Maria Pugliese; Elisabetta Coppi (Purinergic Signalling, 2024)
Interest has been focused in recent years on the analgesic effects exerted by adenosine and its receptors, A 1 , A 2A , A 2B , and A 3 adenosine receptor (AR) subtypes, in different in vivo models of chronic pain. In particular, it was demonstrated that selective A 3 AR agonists reduced pro-nociceptive N-type Ca 2+ channels in dorsal root ganglion (DRG) neurons isolated from rats and, by this mechanism, inhibit post inflammatory visceral hypersensitivity. In the present study, we investigate the effect of a previously reported irreversibly binding A 3 AR agonist, ICBM, on Ca 2+ currents (I Ca ) in rat DRG neurons. Present data demonstrate that ICBM, an isothiocyanate derivative designed for covalent binding to the receptor, concentration-dependently inhibits I Ca . This effect is irreversible, since it persists after drug removal, differently from the prototypical A 3 AR agonist, Cl-IB-MECA. ICBM pre-exposure inhibits the effect of a subsequent Cl-IB-MECA application. Thus, covalent A 3 AR agonists such as ICBM may represent an innovative, beneficial, and longer-lasting strategy to achieve efficacious chronic pain control versus commonly used, reversible, A 3 AR agonists. However, the possible limitations of this drug and other covalent drugs may be, for example, a characteristic adverse effect profile, suggesting that more pre-clinical studies are needed.

Characterization of purinergic signaling in tumor-infiltrating lymphocytes from lower- and high-grade gliomas - Juliete Nathali Scholl; Augusto Ferreira Weber; Camila Kehl Dias; Vinícius Pierdoná Lima; Lucas Kich Grun; Diego Zambonin; Eduardo Anzolin; Wanderson Willian Dos Santos Dias; Willian Pegoraro Kus; Florencia Barbé-Tuana; Ana Maria Oliveira Battastini; Paulo Valdeci Worm; et al. (Purinergic Signalling, 2024)

Caffeine plus haloperidol reduces fatigue in an experimental model of Parkinson's disease – a prospective to A2AR-D2R heterodimer antagonism - Ana Cristina de Bem Alves; Aderbal Silva Aguiar (Purinergic Signalling, 2024)

ATP released from dying cancer cells stimulates P2X4 receptors and mTOR in their neighbors - Haruna Suzuki-Kerr (Purinergic Signalling, 2024)

Retraction Note: Modulation of the TGF-β1-induced epithelial to mesenchymal transition (EMT) mediated by P1 and P2 purine receptors in MDCK cells - Mariachiara Zuccarini; Patricia Giuliani; Silvana Buccella; Valentina Di Liberto; Giuseppa Mudò; Natale Belluardo; Marzia Carluccio; Margherita Rossini; Daniele Filippo Condorelli; Michel Piers Rathbone; Francesco Caciagli; Renata Ciccarelli; et al. (Purinergic Signalling, 2023)

Third meeting of the Australian and New Zealand Purine Club - Reece A. Sophocleous; Ronald Sluyter; Carolina Gubert; Srdjan M. Vlajkovic; Jennie M. E. Cederholm (Purinergic Signalling, 2023)

Retraction Note: Lysophosphatidylcholine induces adenosine release from macrophages via TRPM7-mediated mitochondrial activation - Ahmed M. Youssef; Dong-Keun Song (Purinergic Signalling, 2023)

James Saville Wiley (1936–2022): pioneer of purinergic research in Australia and abroad - Ben J. Gu; Stephen J. Fuller; Kristen K. Skarratt; Leanne Stokes; Malcolm J. Wiley; Ronald Sluyter (Purinergic Signalling, 2023)

EU COST Action CA21130 PRESTO ‘P2X receptors as therapeutic targets’ inaugural meeting report - Luke Tattersall; Ankita Agrawal; Elena Adinolfi; Alison Gartland (Purinergic Signalling, 2023)
The inaugural meeting of the EU COST Action CA21130 PRESTO was held in February 2023, at the University of Ferrara, Italy. Our meeting report provides an overview of PRESTO, a tribute to Professor Jim Wiley, overviews of the talk, and a speaker synopsis that discusses the resources, models, equipment, and techniques available in different lab groups throughout Europe, increasing the prospect of collaborative research.

P2X7 receptor antagonist A-438079 alleviates oxidative stress of lung in LPS-induced septic rats - Seckin Ozkanlar; Nergis Ulas; Ozgur Kaynar; Emine Satici (Purinergic Signalling, 2023)

P2X7 receptor promotes migration and invasion of non-small cell lung cancer A549 cells through the PI3K/Akt pathways - Xue Bai; Qianqian Li; Xiaoxiang Peng; Xinyu Li; Cuicui Qiao; Yiqing Tang; Ronglan Zhao (Purinergic Signalling, 2023)

The striatum drives the ergogenic effects of caffeine - Ana Cristina de Bem Alves; Ana Elisa Speck; Hémelin Resende Farias; Leo Meira Martins; Naiara Souza dos Santos; Gabriela Pannata; Ana Paula Tavares; Jade de Oliveira; Ângelo R. Tomé; Rodrigo A. Cunha; Aderbal S Aguiar (Purinergic Signalling, 2023)

Genetic polymorphisms of purinergic P2Y2 receptor were associated with the susceptibility to essential hypertension in Chinese postmenopausal women - Ao Li; Chaopeng Xiong; Chengxin Gong; Mengyang Gou; Yaqun Wang; Yuping Yang; Hong Xu (Purinergic Signalling, 2023)

A2A receptor signaling drives cisplatin-mediated hippocampal neurotoxicity and cognitive defects in mice - Benjamin B. Gyau; Silvia Deaglio (Purinergic Signalling, 2023)

A promising drug for neuropathic pain: identification of vesicular nucleotide transporter as a novel target of eicosapentaenoic acid - Kozo Saito; Schuichi Koizumi (Purinergic Signalling, 2023)

ATP breakdown in plasma of children limits the antimicrobial effectiveness of their neutrophils - Carola Ledderose; Eleftheria-Angeliki Valsami; Margaret Newhams; Mark-Josef Elevado; Tanya Novak; Adrienne G. Randolph; Wolfgang G. Junger (Purinergic Signalling, 2023)

Transactivation of receptor tyrosine kinases by purinergic P2Y and adenosine receptors - F. G. Vázquez-Cuevas; M. Reyna-Jeldes; E. Velázquez-Miranda; C. Coddou (Purinergic Signalling, 2023)

Istradefylline modulates purinergic enzymes and reduces malignancy-associated factors in B16F10 melanoma cells - Jean Lucas Gutknecht da Silva; Altevir Rossato Viana; Daniela Ferreira Passos; Luciana Maria Fontanari Krause; Vanessa Valéria Miron; Maria Rosa Chitolina Schetinger; Micheli Mainardi Pillat; Taís Vidal Palma; Daniela Bitencourt Rosa Leal (Purinergic Signalling, 2023)

Announcement of changes to the Editorial Board (Purinergic Signalling, 2023)

Adenosine A1 receptor antagonist-induced facilitation of postsynaptic AMPA currents in pyramidal neurons of the rat hippocampal CA2 area - Masahito Kawamura; Yuko Sekino (Purinergic Signalling, 2023)

Editorial: Small molecules and biologics for future purinergic therapeutics - Kenneth A. Jacobson; Daniela Salvemini (Purinergic Signalling, 2023)

Transcriptomic analysis reveals novel age-independent immunomodulatory proteins as a mode of cerebroprotection in P2X4 receptor knockout mice after ischemic stroke - Daylin Gamiotea-Turro; Chunxia C Cronin; Bruce T Liang; Rajkumar Verma (Purinergic Signalling, 2023)

P2Y11/IL-1 receptor crosstalk controls macrophage inflammation: a novel target for anti-inflammatory strategies? - Dominik Klaver; Martin Thurnher (Purinergic Signalling, 2023)
Although first cloning of the human ATP receptor P2Y 11 was successful 25 years ago, the exact downstream signaling pathways of P2Y 11 receptor, which can couple to G q and G s proteins, have remained unclear. Especially the lack of rodent models as well as the limited availability of antibodies and pharmacological tools have hampered examination of P2Y 11 expression and function. Many meaningful observations related to P2Y 11 have been made in primary immune cells, indicating that P2Y 11 receptors are important regulators of inflammation and cell migration, also by controlling mitochondrial activity. Our recent studies have shown that P2Y 11 is upregulated during macrophage development and activates signaling through IL-1 receptor, which is well known for its ability to direct inflammatory and migratory processes. This review summarizes the results of the first transcriptomic and secretomic analyses of both, ectopic and native P2Y 11 receptors, and discusses how P2Y 11 crosstalk with the IL-1 receptor may govern anti-inflammatory and pro-angiogenic processes in human M2 macrophages.

DT-0111: a novel P2X3 receptor antagonist - Amir Pelleg; Elena Sirtori; Jean-Francois Rolland; Anu Mahadevan (Purinergic Signalling, 2023)

In vivo phenotypic validation of adenosine receptor-dependent activity of non-adenosine drugs - Cuiying Xiao; Oksana Gavrilova; Naili Liu; Sarah A. Lewicki; Marc L. Reitman; Kenneth A. Jacobson (Purinergic Signalling, 2023)

Targeting the A3 adenosine receptor to treat hepatocellular carcinoma: anti-cancer and hepatoprotective effects - Pnina Fishman; Salomon M. Stemmer; Avital Bareket-Samish; Michael H. Silverman; William D. Kerns (Purinergic Signalling, 2023)
The A3 adenosine receptor (A3AR) is over-expressed in human hepatocellular carcinoma (HCC) cells. Namodenoson, an A3AR agonist, induces de-regulation of the Wnt and NF-kB signaling pathways resulting in apoptosis of HCC cells. In a phase I healthy volunteer study and in a phase I/II study in patients with advanced HCC, namodenoson was safe and well tolerated. Preliminary evidence of antitumor activity was observed in the phase I/II trial in a subset of patients with advanced disease, namely patients with Child–Pugh B (CPB) hepatic dysfunction, whose median overall survival (OS) on namodenoson was 8.1 months. A phase II blinded, randomized, placebo-controlled trial was subsequently conducted in patients with advanced HCC and CPB cirrhosis. The primary endpoint of OS superiority over placebo was not met. However, subgroup analysis of CPB7 patients (34 namodenoson-treated, 22 placebo-treated) showed nonsignificant differences in OS/progression-free survival and a significant difference in 12-month OS (44% vs 18%, p = 0.028). Partial response was achieved in 9% of namodenoson-treated patients vs 0% in placebo-treated patients. Based on the positive efficacy signal in HCC CPB7 patients and the favorable safety profile of namodenoson, a phase III study is underway.

Species dependence of A3 adenosine receptor pharmacology and function - Zhan-Guo Gao; John A. Auchampach; Kenneth A. Jacobson (Purinergic Signalling, 2023)

Activation of P2X4 receptors in midbrain cerebrospinal fluid-contacting nucleus leads to mechanical hyperalgesia in chronic constriction injury rats - Wei Song; Yue Yong; Yalan Zhou; Liyue Lu; Guijie Yu; Wei Tang; Jian Wang; Jun Guo; Lili Li; Licai Zhang; Jiangang Song (Purinergic Signalling, 2023)

Fluorescent A2A and A3 adenosine receptor antagonists as flow cytometry probes - Kiran S. Toti; Ryan G. Campbell; Hobin Lee; Veronica Salmaso; R. Rama Suresh; Zhan-Guo Gao; Kenneth A. Jacobson (Purinergic Signalling, 2023)

Editorial: Special issue on purinergic signalling and calcification - Isabel R. Orriss; Timothy R. Arnett (Purinergic Signalling, 2023)

Correction to: Purinoceptor: a novel target for hypertension - Xuan Li; Li-juan Zhu; Jing Lv; Xin Cao (Purinergic Signalling, 2023)

Increasing inosine/decreasing ENT1: promising strategies for anti-obesity therapy - Lei Yan; Yong Tang (Purinergic Signalling, 2023)

The adenosine-A2AR-PKA axis in iSPNs: a novel contributor to regulation of locomotion - Zhi-Wen Yuan; Yong Tang (Purinergic Signalling, 2023)

Emerging roles of the P2X7 receptor in cancer pain - Ping Wu; Yin Wang; Yansong Liu; Yan Liu; Guohua Zhou; Xiaoqi Wu; Qingping Wen (Purinergic Signalling, 2023)
Cancer pain is the most prevalent symptom experienced by cancer patients. It substantially impacts a patient’s long-term physical and emotional health, making it a pressing issue that must be addressed. Purinergic receptor P2X7 (P2X7R) is a widely distributed and potent non-selective ATP-gated ion channel that regulates tumor proliferation, chronic pain, and the formation of inflammatory lesions in the central nervous system. P2X7R plays an essential role in cancer pain and complications related to cancer pain including depression and opioid tolerance. This review focuses on the structure and distribution of P2X7R, its role in diverse tissues in cancer pain, and the application of P2X7R antagonists in the treatment of cancer pain to propose new ideas for cancer pain management.

Rehabilitation of the P2X5 receptor: a re-evaluation of structure and function - Brian F. King (Purinergic Signalling, 2023)
Of the extended family of ATP-gated P2X ion-channels, the P2X5 receptor has received comparatively little attention since first cloned over 25 years ago. Disinterest in studying this P2X subtype stems from two commonly held beliefs: (i) canonical human P2X5 is non-functional because the P2X5 subunit is truncated (hP2X5A, 422 aa) and missing the critical peptide sequence (22 aa) encoded by exon 10; (ii) rat and mouse P2X5 subunits are fully formed (455 aa) but the receptor is only weakly functional, and successive ATP responses rapidly run down in amplitude. However, newer studies have re-evaluated these notions. First, a low proportion (around 10%) of humans possess full-length P2X5 subunits (444 aa) and can form competent P2X5 receptors. Full-length P2X5 has been identified only in black Americans, but may occur in a wider population as more ethnicities are screened. Second, replacement of one of three amino acids in rat P2X5 subunits with corresponding residues in human P2X5 subunits (V67I, S191F, or F195H) significantly improves the responsiveness of rat P2X5 to ATP. Replaced residues exert an allosteric action on the left flipper, allowing the docking jaw for ATP to flex the lower body of the subunit and fully open the ion pore. This proposed action may drive the search for naturally occurring modulators which act allosterically on wildtype rat P2X5. This review collates the available information on the structure and function of human and rat P2X5 receptors, with the view to rehabilitating the reputation of these ATP-gated ion channels and stimulating future lines of research.

Therapeutic potential for P2Y2 receptor antagonism - Kimberly J. Jasmer; Kevin Muñoz Forti; Lucas T. Woods; Seunghee Cha; Gary A. Weisman (Purinergic Signalling, 2023)

The antidepressant-like effect of guanosine involves the modulation of adenosine A1 and A2A receptors - Anderson Camargo; Luis E. B. Bettio; Priscila B. Rosa; Julia M. Rosa; Glorister A. Altê; Ana Lúcia S. Rodrigues (Purinergic Signalling, 2023)

The impact of inosine on hippocampal synaptic transmission and plasticity involves the release of adenosine through equilibrative nucleoside transporters rather than the direct activation of adenosine receptors - Pedro Valada; Sonja Hinz; Christin Vielmuth; Cátia R. Lopes; Rodrigo A. Cunha; Christa E. Müller; João Pedro Lopes (Purinergic Signalling, 2023)

Modulation of osteoblast differentiation and function by the P2X4 receptor - Isabel R. Orriss; Bethan K. Davies; Lucie E. Bourne; Timothy R. Arnett (Purinergic Signalling, 2023)
Bone cells are known to express multiple P2 receptor subtypes, and the functional effects of receptor activation have been described for many of these. One exception is the P2X4 receptor, which despite strong expression in osteoblasts and osteoclasts, has no defined functional activity. This study used the selective P2X4 receptor antagonists, 5-BDBD and PSB-12062, to investigate the role of this receptor in bone. Both antagonists (≥ 0.1 μM) dose-dependently decreased bone formation by 60–100%. This was accompanied by a ≤ 70% decrease in alkaline phosphatase activity, a ≤ 40% reduction in cell number, and a ≤ 80% increase in the number of adipocytes present in the culture. The analysis of gene expression showed that levels of osteoblast marker genes (e.g. Alpl , Bglap ) were decreased in 5-BDBD treated cells. Conversely, expression of the adipogenic transcription factor PPARG was increased 10-fold. In osteoclasts, high doses of both antagonists were associated with a reduction in osteoclast formation and resorptive activity by ≤ 95% and ≤ 90%, respectively. Taken together, these data suggest that the P2X4 receptor plays a role in modulating bone cell function. In particular, it appears to influence osteoblast differentiation favouring the osteogenic lineage over the adipogenic lineage.

NPP1 and TNAP hydrolyze ATP synergistically during biomineralization - Luiz H. S. Andrilli; Heitor G. Sebinelli; Bruno Z. Favarin; Marcos A. E. Cruz; Ana Paula Ramos; Mayte Bolean; José Luis Millán; Massimo Bottini; Pietro Ciancaglini (Purinergic Signalling, 2023)

Role of the extracellular ATP/pyrophosphate metabolism cycle in vascular calcification - Ricardo Villa-Bellosta (Purinergic Signalling, 2023)

Editorial: Purinergic signalling — a perspective from China - Yong Tang; Jiang-Fan Chen; Peter Illes (Purinergic Signalling, 2023)

Purinergic receptor: a crucial regulator of adipose tissue functions - Dan Wang; Jianwei Zhou (Purinergic Signalling, 2023)

Purinergic signaling: a potential therapeutic target for ischemic stroke - Lu Wang; Ying-Jie Li; Xu Yang; Bo Yang; Xin Zhang; Jing Zhang; Qi Zhang; Xu-Dong Cheng; Jian-Hong Wang; Neng-Wei Yu (Purinergic Signalling, 2023)

Exploration of the link between gut microbiota and purinergic signalling - MingJian Li; BoWen Liu; Rong Li; Ping Yang; Ping Leng; Yong Huang (Purinergic Signalling, 2023)
Growing evidence reveals that microorganisms in the gut are linked to metabolic health and disease risk in human beings to a considerable extent. The focus of research at this stage must tend to focus on cause-and-effect studies. In addition to being a component of DNA and RNA, purine metabolites can be involved in purine signalling in the body as chemical messengers. Abnormalities in purinergic signalling may lead to neuropathy, rheumatic immune diseases, inflammation, tumors, and a wide range of other diseases. It has proved that gut microbes are involved in purinergic signalling. The relationship between these gut-derived purinergic signalling molecules and host metabolism may be one of the important clues to our understanding of the mechanisms by which the microbiota affects host metabolism.

The circadian regulation of extracellular ATP - Xin Wang; Yu-Ting Dong; Xiu-Ming Hu; Ji-Zhou Zhang; Nan-Rui Shi; Yan-Qin Zuo; Xu Wang (Purinergic Signalling, 2023)
Extracellular ATP is a potent signaling molecule released from various cells throughout the body and is intimately involved in the pathophysiological functions of the nervous system and immune system by activating P2 purinergic receptors. Recent increasingly studies showed that extracellular ATP exhibits circadian oscillation with an approximately 24-h periodicity, which participates in regulatory pathways of central oscillator suprachiasmatic nucleus and peripheral oscillator bladder, respectively. Oscillators modulate the protein expression of ATP release channels and ectonucleotidase activity through clock genes; indeed, real-time alterations of ATP release and degradation determine outcomes of temporal character on extracellular ATP rhythm. The regulatory pathways on extracellular ATP rhythm are different in central and peripheral systems. In this review, we summarize the circadian rhythm of extracellular ATP and discuss several circadian regulatory pathways in different organs via ATP release and degradation, to provide a new understanding for purinergic signaling in the regulatory mechanism of circadian rhythm and a potential target to research the circadian regulation of extracellular ATP in other circadian oscillators.

P2Y1R and P2Y2R: potential molecular triggers in muscle regeneration - Min-Jia Wang; Bi-Ru Yang; Xin-Yu Jing; Yao-Zheng Wang; Lu Kang; Kai Ren; Liang Kang (Purinergic Signalling, 2023)
Muscle regeneration is indispensable for skeletal muscle health and daily life when injury, muscular disease, and aging occur. Among the muscle regeneration, muscle stem cells’ (MuSCs) activation, proliferation, and differentiation play a key role in muscle regeneration. Purines bind to its specific receptors during muscle development, which transmit environmental stimuli and play a crucial role of modulator of muscle regeneration. Evidences proved P2R expression during development and regeneration of skeletal muscle, both in human and mouse. In contrast to P2XR, which have been extensively investigated in skeletal muscles, the knowledge of P2YR in this tissue is less comprehensive. This review summarized muscle regeneration via P2Y1R and P2Y2R and speculated that P2Y1R and P2Y2R might be potential molecular triggers for MuSCs’ activation and proliferation via the p-ERK1/2 and PLC pathways, explored their cascade effects on skeletal muscle, and proposed P2Y1/2 receptors as potential pharmacological targets in muscle regeneration, to advance the purinergic signaling within muscle and provide promising strategies for alleviating muscular disease.

Neuroprotection of exercise: P2X4R and P2X7R regulate BDNF actions - Bing-xin Sun; Ai-shi Peng; Pei-jie Liu; Min-jia Wang; Hai-li Ding; Yu-shi Hu; Liang Kang (Purinergic Signalling, 2023)
The neurotrophin brain-derived neurotrophic factor (BDNF), which acts as a transducer, is responsible for improving cerebral stroke, neuropathic pain, and depression. Exercise can alter extracellular nucleotide levels and purinergic receptors in central nervous system (CNS) structures. This inevitably activates or inhibits the expression of BDNF via purinergic receptors, particularly the P2X receptor (P2XR), to alleviate pathological progression. In addition, the significant involvement of sensitive P2X4R in mediating increased BDNF and p38-MAPK for intracerebral hemorrhage and pain hypersensitivity has been reported. Moreover, archetypal P2X7R blockade induces mouse antidepressant-like behavior and analgesia by BDNF release. This review summarizes BDNF-mediated neural effects via purinergic receptors, speculates that P2X4R and P2X7R could be priming molecules in exercise-mediated changes in BDNF, and provides strategies for the protective mechanism of exercise in neurogenic disease.

The P2 purinoceptors in prostate cancer - Zilin Wang; Sha Zhu; Sirui Tan; Yuhao Zeng; Hao Zeng (Purinergic Signalling, 2023)
P2 purinoceptors are composed of ligand-gated ion channel type (P2X receptor) and G protein-coupled metabolite type (P2Y receptor). Both these receptors have played important roles in the prostate cancer microenvironment in recent years. P2X and P2Y receptors can contribute to prostate cancer’s growth and invasiveness. However, the comprehensive mechanisms have yet to be identified. By summarizing the relevant studies, we believe that P2X and P2Y receptors play a dual role in cancer cell growth depending on the prostate cancer microenvironment and different downstream signalling pathways. We also summarized how different signalling pathways contribute to tumor invasiveness and metastasis through P2X and P2Y receptors, focusing on understanding the specific mechanisms led by P2X4, P2X7, and P2Y2. Statins may reduce and prevent tumor progression through P2X7 so that P2X purinergic receptors may have clinical implications in the management of prostate cancer. Furthermore, P2X7 receptors can aid in the early detection of prostate cancer. We hope that this review will provide new insights for future mechanistic and clinical investigations into the role of P2 purinergic receptors in prostate cancer.

Spinal P2X4 Receptors Involved in Visceral Hypersensitivity of Neonatal Maternal Separation Rats - Ying Tang; Li Chen; Bin Liu; Pei Sun; Zhong Chen; Yang Huang; Chen Ai-qin; Yu Chen; Chun Lin (Purinergic Signalling, 2023)

Analgesic effect of electroacupuncture on bone cancer pain in rat model: the role of peripheral P2X3 receptor - Shu-xin Tian; Ting Xu; Ren-yi Shi; Yang-qian Cai; Ming-hui Wu; Si-jia Zhen; Wen Wang; You Zhou; Jun-ying Du; Jun-fan Fang; Xiao-mei Shao; Bo-yi Liu; et al. (Purinergic Signalling, 2023)

Spinal cord astrocyte P2X7Rs mediate the inhibitory effect of electroacupuncture on visceral hypersensitivity of rat with irritable bowel syndrome - Zhi-jun Weng; Shi-xiu Hu; Fang Zhang; Zhi-ying Zhang; Yun Zhou; Min Zhao; Yan Huang; Yu-hu Xin; Huan-gan Wu; Hui-rong Liu (Purinergic Signalling, 2023)

Purinergic signaling in thyroid disease - Ying Le; Donghui Lu; Meng Xue (Purinergic Signalling, 2023)

Purinergic signaling in myocardial ischemia–reperfusion injury - Yi Zhuang; Mei-ling Yu; Sheng-feng Lu (Purinergic Signalling, 2023)

P2X7 receptor involved in antitumor activity of atractylenolide I in human cervical cancer cells - Yue Han; Can Bai; Xi-Meng He; Qing-Ling Ren (Purinergic Signalling, 2023)
Atractylenolide I (Atr-I) was found to sensitize a variety of human cancer cells in previous studies. Purinergic P2X7R plays important role in different cancers. However, whether Atr-I could generate antitumor activity in human cervical cancer cells and P2X7R get involved in this effect remain unclear. In this study, Hela (HPV 18 +) and SiHa (HPV 16 +) cells were treated with different doses of Atr-I. The results indicated that agonist and antagonist of P2X7 receptors, BzATP and JNJ-47965567 (JNJ), could suppress the proliferation of Hela and SiHa cells. Atr-I demonstrated a considerable antitumor effect in both human cervical cancer cells in vitro. Atr-I combined with P2X7R agonist, BzATP, restored Atr-I-induced growth inhibition in Hela cells but not in SiHa cells. However, the combinatorial treatment of P2X7R antagonist JNJ and Atr-I has an additive effect on cell growth inhibition in SiHa cells rather than in Hela cells. It implied that P2X7R would get involved in the anti-human cervical cancer cells effect of Atr-I.

Dorsal root ganglia P2X4 and P2X7 receptors contribute to diabetes-induced hyperalgesia and the downregulation of electroacupuncture on P2X4 and P2X7 - Qun-qi Hu; Xiao-fen He; Yi-qi Ma; Li-qian Ma; Si-ying Qu; Han-zhi Wang; Yu-rong Kang; Lu-hang Chen; Xiang Li; Bo-yu Liu; Xiao-mei Shao; Jun-fan Fang; et al. (Purinergic Signalling, 2023)

Targeting purinergic receptors to attenuate inflammation of dry eye - Jia-Ning Wang; Hua Fan; Jian-Tao Song (Purinergic Signalling, 2023)
Inflammation is one of the potential factors to cause the damage of ocular surface in dry eye disease (DED). Increasing evidence indicated that purinergic A 1 , A 2A , A 3 , P2X4, P2X7, P2Y 1 , P2Y 2 , and P2Y 4 receptors play an important role in the regulation of inflammation in DED: A 1 adenosine receptor (A 1R ) is a systemic pro-inflammatory factor; A 2AR is involved in the activation of the MAPK/NF-kB pathway; A 3R combined with inhibition of adenylate cyclase and regulation of the mitogen-activated protein kinase (MAPK) pathway leads to regulation of transcription; P2X4 promotes receptor-associated activation of pro-inflammatory cytokines and inflammatory vesicles; P2X7 promotes inflammasome activation and release of pro-inflammatory cytokines IL-1β and IL-18; P2Y receptors affect the phospholipase C(PLC)/IP3/Ca 2+ signaling pathway and mucin secretion. These suggested that purinergic receptors would be promising targets to control the inflammation of DED in the future.

Purinoceptor: a novel target for hypertension - Xuan Li; Li-juan Zhu; Jing Lv; Xin Cao (Purinergic Signalling, 2023)
Hypertension is the leading cause of morbidity and mortality globally among all cardiovascular diseases. Purinergic signalling plays a crucial role in hypertension through the sympathetic nerve system, neurons in the brain stem, carotid body, endothelium, immune system, renin-angiotensin system, sodium excretion, epithelial sodium channel activity (ENaC), and renal autoregulation. Under hypertension, adenosine triphosphate (ATP) is released as a cotransmitter from the sympathetic nerve. It mediates vascular tone mainly through P2X1R activation on smooth muscle cells and activation of P2X4R and P2YR on endothelial cells and also via interaction with other purinoceptors, showing dual effects. P2Y1R is linked to neurogenic hypertension. P2X7R and P2Y11R are potential targets for immune-related hypertension. P2X3R located on the carotid body is the most promising novel therapeutic target for hypertension. A 1 R, A 2A R, A 2B R, and P2X7R are all related to renal autoregulation, which contribute to both renal damage and hypertension. The main focus is on the evidence addressing the involvement of purinoceptors in hypertension and therapeutic interventions.

P2Y12 receptor gene polymorphisms are associated with epilepsy - Qi Wang; Nan-Rui Shi; Peng Lv; Juan Liu; Ji-Zhou Zhang; Bin-Lu Deng; Yan-Qin Zuo; Jie Yang; Xin Wang; Xiang Chen; Xiu-Min Hu; Ting-Ting Liu; et al. (Purinergic Signalling, 2023)
The basic research indicated that microglial P2Y12 receptors ( P2Y12Rs ) are involved in the pathophysiology of epilepsy through regulated microglial-neuronal interactions, aberrant neurogenesis, or immature neuronal projections. However, whether the clinic case of epilepsy would be associated with P2Y12 receptor gene polymorphisms is presented with few data. In our study, a total of 176 patients with epilepsy and 50 healthy controls were enrolled. Two single-nucleotide polymorphisms, namely rs1491974 and rs6798347, were selected for analysis. The results revealed that carriers of the G allele of rs1491974 G>A or rs6798347 G>A may be associated with an increased risk of epilepsy (OR = 0.576, 95% CI = 0.368–0.901, p = 0.015; OR = 0.603, 95% CI = 0.367–0.988, p = 0.043). Interestingly, we found that the rs1491974 G>A genotype and allele frequencies have only a significant difference in female instead of male case ( p = 0.004 for genotype; p = 0.001 for allele). The subgroup analysis demonstrated that individuals with the rs1491974 G>A genotype might have more frequent seizure (OR = 0.476, 95% CI = 0.255–0.890; p = 0.019). These data implied that both rs1491974 and rs6798347 polymorphisms of P2Y12R would be able to play import roles in epilepsy susceptibility, whereas the rs1491974 polymorphism may be specifically related to seizure frequency.

Adenosine A2A receptor controls the gateway of the choroid plexus - Mengqian Ye; Mengru Wang; Yijia Feng; Huiping Shang; Yuwen Yang; Lanxin Hu; Muran Wang; Serhii Vakal; Xiangxiang Lin; Jiangfan Chen; Wu Zheng (Purinergic Signalling, 2023)

The real-time detection of acupuncture-induced extracellular ATP mobilization in acupoints and exploration of its role in acupuncture analgesia - Wei-Min Zuo; Yu-Jia Li; Kai-Yu Cui; Dan Shen; Di Zhang; Ya-Wen Zheng; Meng Huang; Yong Wu; Xue-Yong Shen; Li-Na Wang; Guang-Hong Ding (Purinergic Signalling, 2023)

MicroRNA: Crucial modulator in purinergic signalling involved diseases - Jing Guo; Peng Yang; Yi-Fan Li; Jin-Fan Tang; Zhao-Xuan He; Shu-Guang Yu; Hai-Yan Yin (Purinergic Signalling, 2023)
Both microRNAs (miRNAs) and purinergic signalling are widely and respectively expressed in various tissues of different organisms and play vital roles in a variety of physiological and pathological processes. Here, we reviewed the current publications contributed to the relationship of miRNAs and purinergic signalling in cardiovascular diseases, gastrointestinal diseases, neurological diseases, and ophthalmic diseases. We tried to decode the miRNAs-purinergic signalling network of purinergic signalling involved diseases. The evidence indicated that more than 30 miRNAs (miR-22, miR-30, miR-146, miR-150, miR-155, miR-187, etc.) directly or indirectly modulate P1 receptors (A 1 , A 2A , A 2B , A 3 ), P2 receptors (P2X1, P2X3, P2X4, P2X7, P2Y2, P2Y6, P2Y12), and ecto-enzymes (CD39, CD73, ADA2); P2X7 and CD73 could be modulated by multiple miRNAs (P2X7: miR-21, miR-22, miR-30, miR-135a, miR-150, miR-186, miR-187, miR-216b; CD73: miR-141, miR-101, miR-193b, miR-340, miR-187, miR-30, miR-422a); miR-187 would be the common miRNA to modulate P2X7 and CD73.

P2X7Rs: new therapeutic targets for osteoporosis - Haoyun Huang; Yu-Mei He; Miao-Miao Lin; Yanchao Wang; Xiaomei Zhang; Li Liang; Xueling He (Purinergic Signalling, 2023)
Increasing evidence suggests that both the occurrence and progression of osteoporosis are associated with inflammation, especially in primary osteoporosis. The maintenance of skeletal homeostasis is dependent on the complex regulation of bone metabolism. Numerous evidence suggested that purinoceptor networks are essential for bone homeostasis. In this review, the relationship between inflammation and the development of osteoporosis and the role of P2X7 receptor (P2X7R) in regulating the dynamic regulation of bone reconstruction were covered. We also discussed how P2X7R regulates the balance between resorption and bone formation by osteoblasts and reviewed the relevance of P2X7R polymorphisms in skeletal physiology. Finally, we analyzed potential targets of P2X7R for osteoporosis.

Involvement of purinergic P2Y1R in antidepressant-like effects of electroacupuncture treatment on social isolation stress mice - Lingling Yu; Yao Wang; Hong Zhang; Man Li; Guang Chen; Jiahuan Hao; Minjie Xie (Purinergic Signalling, 2023)

Long non-coding RNA MSTRG.81401 short hairpin RNA relieves diabetic neuropathic pain and behaviors of depression by inhibiting P2X4 receptor expression in type 2 diabetic rats - Mengyun Sun; Mingming Zhang; Haoming Yin; Hongcheng Tu; Yuqing Wen; Xingyu Wei; Wenhao shen; Ruoyu Huang; Wei Xiong; Guodong Li; Yun Gao (Purinergic Signalling, 2023)

Adenosine signaling mediate pain transmission in the central nervous system - Mengmeng Zhou; Jinrong Wu; Hongen Chang; Yuxin Fang; Di Zhang; Yi Guo (Purinergic Signalling, 2023)

Purinergic receptors mediate endothelial dysfunction and participate in atherosclerosis - Xian-Ming Wu; Ning Zhang; Jiang-Shan Li; Zhi-Hong Yang; Xiao-Lou Huang; Xiao-Fang Yang (Purinergic Signalling, 2023)
Atherosclerosis is the main pathological basis of cardiovascular disease and involves damage to vascular endothelial cells (ECs) that results in endothelial dysfunction (ED). The vascular endothelium is the key to maintaining blood vessel health and homeostasis. ED is a complex pathological process involving inflammation, shear stress, vascular tone, adhesion of leukocytes to ECs, and platelet aggregation. The activation of P2X4, P2X7, and P2Y2 receptors regulates vascular tone in response to shear stress, while activation of the A2A, P2X4, P2X7, P2Y1, P2Y2, P2Y6, and P2Y12 receptors promotes the secretion of inflammatory cytokines. Finally, P2X1, P2Y1, and P2Y12 receptor activation regulates platelet activity. These purinergic receptors mediate ED and participate in atherosclerosis. In short, P2X4, P2X7, P2Y1, and P2Y12 receptors are potential therapeutic targets for atherosclerosis.

Inhibition of phosphorylated calcium/calmodulin-dependent protein kinase IIα relieves streptozotocin-induced diabetic neuropathic pain through regulation of P2X3 receptor in dorsal root ganglia - Xiao-fen He; Yu-rong Kang; Xue-yu Fei; Lu-hang Chen; Xiang Li; Yi-qi Ma; Qun-qi Hu; Si-ying Qu; Han-zhi Wang; Xiao-mei Shao; Bo-yi Liu; Yi-Liang; et al. (Purinergic Signalling, 2023)
Diabetic neuropathic pain (DNP) is frequent among patients with diabetes. We previously showed that P2X3 upregulation in dorsal root ganglia (DRG) plays a role in streptozotocin (STZ)-induced DNP but the underlying mechanism is unclear. Here, a rat model of DNP was established by a single injection of STZ (65 mg/kg). Fasting blood glucose was significantly elevated from the 1 st to 3 rd week. Paw withdrawal thresholds (PWTs) and paw withdrawal latencies (PWLs) in diabetic rats significantly reduced from the 2 nd to 3 rd week. Western blot analysis revealed that elevated p-CaMKIIα levels in the DRG of DNP rats were accompanied by pain-associated behaviors while CaMKIIα levels were unchanged. Immunofluorescence revealed significant increase in the proportion of p-CaMKIIα immune positive DRG neurons (stained with NeuN) in the 2 nd and 3 rd week and p-CaMKIIα was co-expressed with P2X3 in DNP rats. KN93, a CaMKII antagonist, significantly reduce mechanical hyperalgesia and thermal hyperalgesia and these effects varied dose-dependently, and suppressed p-CaMKIIα and P2X3 upregulation in the DRGs of DNP rats. These results revealed that the p-CaMKIIα upregulation in DRG is involved in DNP, which possibly mediated P2X3 upregulation, indicating CaMKIIα may be an effective pharmacological target for DNP management.

In silico identification of A1 agonists and A2a inhibitors in pain based on molecular docking strategies and dynamics simulations - Guangya Xu; Shutao Zhang; Lulu Zheng; Zhongjiao Hu; Lijia Cheng; Lvlin Chen; Jun Li; Zheng Shi (Purinergic Signalling, 2023)
Most recently, the adenosine is considered as one of the most promising targets for treating pain, with few side effects. It exists in the central nervous system, and plays a key role in nociceptive afferent pathway. It is reported that the A1 receptor (A1R) could inhibit Ca 2+ channels to reduce the pain like analgesic mechanism of morphine. And, A2a receptor (A2aR) was reported to enhance the accumulation of AMP (cAMP) and released peptides from sensory neurons, resulting in constitutive activation of pain. Much evidence showed that A1R and A2aR could be served as the interesting targets for the treatment of pain. Herein, virtual screening was utilized to identify the small molecule compounds towards A1R and A2aR, and top six molecules were considered as candidates via amber scores. The molecular dynamic (MD) simulations and molecular mechanics/generalized born surface area (MM/GBSA) were employed to further analyze the affinity and binding stability of the six molecules towards A1R and A2aR. Moreover, energy decomposition analysis showed significant residues in A1R and A2aR, including His1383, Phe1276, and Glu1277. It provided basics for discovery of novel agonists and antagonists. Finally, the agonists of A1R (ZINC19943625, ZINC13555217, and ZINC04698406) and inhibitors of A2aR (ZINC19370372, ZINC20176051, and ZINC57263068) were successfully recognized. Taken together, our discovered small molecules may serve as the promising candidate agents for future pain research.

Purinergic ATP triggers moxibustion-induced local anti-nociceptive effect on inflammatory pain model - Hai-Yan Yin; Ya-Peng Fan; Juan Liu; Dao-Tong Li; Jing Guo; Shu-Guang Yu (Purinergic Signalling, 2023)
Purinergic signalling adenosine and its A1 receptors have been demonstrated to get involved in the mechanism of acupuncture (needling therapy) analgesia. However, whether purinergic signalling would be responsible for the local analgesic effect of moxibustion therapy, the predominant member in acupuncture family procedures also could trigger analgesic effect on pain diseases, it still remains unclear. In this study, we applied moxibustion to generate analgesic effect on complete Freund’s adjuvant (CFA)-induced inflammatory pain rats and detected the purine released from moxibustioned-acupoint by high-performance liquid chromatography (HPLC) approach. Intramuscular injection of ARL67156 into the acupoint Zusanli (ST36) to inhibit the breakdown of ATP showed the analgesic effect of moxibustion was increased while intramuscular injection of ATPase to speed up ATP hydrolysis caused a reduced moxibustion-induced analgesia. These data implied that purinergic ATP at the location of ST36 acupoint is a potentially beneficial factor for moxibustion-induced analgesia.

Purinergic signaling: a potential therapeutic target for depression and chronic pain - Yuting Zou; Runan Yang; Lin Li; Xiumei Xu; Shangdong Liang (Purinergic Signalling, 2023)

Publisher Correction to: Adenosine receptor signalling in Alzheimer’s disease - Phuc N. H. Trinh; Jo-Anne Baltos; Shane D. Hellyer; Lauren T. May; Karen J. Gregory (Purinergic Signalling, 2022)

Editorial: purinergic signalling—perspectives from Australia and New Zealand - Ronald Sluyter; Jennie M. E. Cederholm; Srdjan M. Vlajkovic (Purinergic Signalling, 2022)

The developmental journey of therapies targeting purine receptors: from basic science to clinical trials - Seunga Han; Haruna Suzuki-Kerr; Srdjan M. Vlajkovic; Peter R. Thorne (Purinergic Signalling, 2022)
Since the discovery of ATP as an extracellular signalling molecule in 1972, purinergic signalling, mediated by extracellular purines and pyrimidines has been identified in virtually all mammalian tissues and is implicated in regulating fundamental cellular processes. In recent years, there has been an increasing focus on the pathophysiology and potential therapeutic interventions based on purinergic signalling. A vast range of compounds targeting purine receptors are in clinical development, and many more are in preclinical studies, which highlights the fast growth in this research field. As a tribute to Professor Geoffrey Burnstock’s legacy in purinergic signalling, we present here a brief review of compounds targeting purine receptors that are in different stages of clinical trials. The review highlights the 50-year journey from basic research on purinergic receptors to clinical applications of therapies targeting purine receptors.

Characterisation of P2Y receptor subtypes mediating vasodilation and vasoconstriction of rat pulmonary artery using selective antagonists - Markie O. Dales; Callum Mitchell; Alison M. Gurney; Robert M. Drummond; Charles Kennedy (Purinergic Signalling, 2022)
Pulmonary vascular tone is modulated by nucleotides, but which P2 receptors mediate these actions is largely unclear. The aim of this study, therefore, was to use subtype-selective antagonists to determine the roles of individual P2Y receptor subtypes in nucleotide-evoked pulmonary vasodilation and vasoconstriction. Isometric tension was recorded from rat intrapulmonary artery rings (i.d. 200–500 µm) mounted on a wire myograph. Nucleotides evoked concentration- and endothelium-dependent vasodilation of precontracted tissues, but the concentration–response curves were shallow and did not reach a plateau. The selective P2Y 2 antagonist, AR-C118925XX, inhibited uridine 5′-triphosphate (UTP)- but not adenosine 5′-triphosphate (ATP)-evoked relaxation, whereas the P2Y 6 receptor antagonist, MRS2578, had no effect on UTP but inhibited relaxation elicited by uridine 5′-diphosphate (UDP). ATP-evoked relaxations were unaffected by the P2Y 1 receptor antagonist, MRS2179, which substantially inhibited responses to adenosine 5′-diphosphate (ADP), and by the P2Y 12/13 receptor antagonist, cangrelor, which potentiated responses to ADP. Both agonists were unaffected by CGS1593, an adenosine receptor antagonist. Finally, AR-C118925XX had no effect on vasoconstriction elicited by UTP or ATP at resting tone, although P2Y 2 receptor mRNA was extracted from endothelium-denuded tissues using reverse transcription polymerase chain reaction with specific oligonucleotide primers. In conclusion, UTP elicits pulmonary vasodilation via P2Y 2 receptors, whereas UDP acts at P2Y 6 and ADP at P2Y 1 receptors, respectively. How ATP induces vasodilation is unclear, but it does not involve P2Y 1 , P2Y 2 , P2Y 12 , P2Y 13 , or adenosine receptors. UTP- and ATP-evoked vasoconstriction was not mediated by P2Y 2 receptors. Thus, this study advances our understanding of how nucleotides modulate pulmonary vascular tone.

P2X7-mediated alteration of membrane fluidity is associated with the late stages of age-related macular degeneration - Candace Drysdale; Keunha Park; Kirstan A. Vessey; Xin Huang; Emily Caruso; Yihan Li; Joelyn Wong; James S. Wiley; Erica Fletcher; Robyn H. Guymer; Ben J. Gu (Purinergic Signalling, 2022)

Inhibition of P2X7 receptors by Lu AF27139 diminishes colonic hypersensitivity and CNS prostanoid levels in a rat model of visceral pain - Roland G. W. Staal; Adarsh Gandhi; Hua Zhou; Manuel Cajina; Anne-Marie Jacobsen; Sara Hestehave; Allen Hopper; Suresh Poda; Gamini Chandresana; Stevin H. Zorn; Brian Campbell; Marta Segerdahl; et al. (Purinergic Signalling, 2022)

Identification of novel proteins involved in P2X7-mediated signaling cascades - Lukas Sassenbach (Purinergic Signalling, 2022)
High concentration of extracellular ATP acts as a danger signal that is sensed by the P2X7 receptor (P2X7R). This ATP-gated ion channel has been shown to induce multiple metabotropic events such as changes in plasma membrane composition and morphology, ectodomain shedding, activation of lipases, kinases, and transcription factors as well as cytokine release. The specific signaling pathways and molecular mechanisms remain largely obscure. Using an unbiased genome-scale CRISPR/Cas9 screening approach in a murine T cell line, Ryoden et al. (2022, 2020) identified three proteins involved in P2X7 regulation and signaling: Essential for Reactive Oxygen Species (EROS) is essential for P2X7 folding and maturation, and Xk and Vsp13a are required for P2X7-mediated phosphatidyl serine exposure and cell lysis. They further provide evidence for an interaction of Xk and Vsp13a at the plasma membrane and confirm the role of Xk in ATP-induced cytolysis in primary CD25 + CD4 + T cells from Xk −/− mice.

CD39 in the development and progression of pulmonary arterial hypertension - Abbey Willcox; Natasha Ting Lee; Harshal H. Nandurkar; Maithili Sashindranath (Purinergic Signalling, 2022)
Pulmonary arterial hypertension (PAH) is a devastating progressive disease characterised by pulmonary arterial vasoconstriction and vascular remodelling. Endothelial dysfunction has emerged as a contributing factor in the development of PAH. However, despite progress in the understanding of the pathophysiology of this disease, current therapies fail to impact upon long-term outcomes which remain poor in most patients. Recent observations have suggested the disturbances in the balance between ATP and adenosine may be integral to the vascular remodelling seen in PAH. CD39 is an enzyme important in regulating these nucleos(t)ides which may also provide a novel pathway to target for future therapies. This review summarises the role of adenosine signalling in the development and progression of PAH and highlights the therapeutic potential of CD39 for treatment of PAH.

P2Y12 receptor antagonism inhibits proliferation, migration and leads to autophagy of glioblastoma cells - Pedro Vargas; Thamiris Becker Scheffel; Fernando Mendonça Diz; Liliana Rockenbach; Nathália Grave; Angélica Regina Cappellari; Luiza Wilges Kist; Maurício Reis Bogo; Marcos Paulo Thomé; Gabriel Fernandes Leal; Amanda de Fraga Dias; Fabrício Figueiró; et al. (Purinergic Signalling, 2022)

The P2X1 receptor as a therapeutic target - Felix M. Bennetts; Jesse I. Mobbs; Sabatino Ventura; David M. Thal (Purinergic Signalling, 2022)
Within the family of purinergic receptors, the P2X1 receptor is a ligand-gated ion channel that plays a role in urogenital, immune and cardiovascular function. Specifically, the P2X1 receptor has been implicated in controlling smooth muscle contractions of the vas deferens and therefore has emerged as an exciting drug target for male contraception. In addition, the P2X1 receptor contributes to smooth muscle contractions of the bladder and is a target to treat bladder dysfunction. Finally, platelets and neutrophils have populations of P2X1 receptors that could be targeted for thrombosis and inflammatory conditions. Drugs that specifically target the P2X1 receptor have been challenging to develop, and only recently have small molecule antagonists of the P2X1 receptor been available. However, these ligands need further biological validation for appropriate selectivity and drug-like properties before they will be suitable for use in preclinical models of disease. Although the atomic structure of the P2X1 receptor has yet to be determined, the recent discovery of several other P2X receptor structures and improvements in the field of structural biology suggests that this is now a distinct possibility. Such efforts may significantly improve drug discovery efforts at the P2X1 receptor.

P2X7 receptor activation mediates superoxide dismutase 1 (SOD1) release from murine NSC-34 motor neurons - Rachael Bartlett; Diane Ly; Neil R. Cashman; Ronald Sluyter; Justin J. Yerbury (Purinergic Signalling, 2022)
Mutant superoxide dismutase 1 (SOD1) can be constitutively released from motor neurons and transmitted to naïve motor neurons to promote the progression of amyotrophic lateral sclerosis (ALS). However, the biological impacts of this process and the precise mechanisms of SOD1 release remain to be fully resolved. Using biochemical and fluorescent techniques, this study aimed to determine if P2X7 receptor activation could induce mutant SOD1 release from motor neurons and whether this released SOD1 could be transmitted to motor neurons or microglia to mediate effects associated with neurodegeneration in ALS. Aggregated SOD1 G93A , released from murine NSC-34 motor neurons transiently transfected with SOD1 G93A , could be transmitted to naïve NSC-34 cells and murine EOC13 microglia to induce endoplasmic reticulum (ER) stress and tumour necrosis factor-alpha (TNFα) release, respectively. Immunoblotting revealed NSC-34 cells expressed P2X7. Extracellular ATP induced cation dye uptake into these cells, which was blocked by the P2X7 antagonist AZ10606120, demonstrating these cells express functional P2X7. Moreover, ATP induced the rapid release of aggregated SOD1 G93A from NSC-34 cells transiently transfected with SOD1 G93A , a process blocked by AZ10606120 and revealing a role for P2X7 in this process. ATP-induced SOD1 G93A release coincided with membrane blebbing. Finally, aggregated SOD1 G93A released via P2X7 activation could also be transmitted to NSC-34 and EOC13 cells to induce ER stress and TNFα release, respectively. Collectively, these results identify a novel role for P2X7 in the prion-like propagation of SOD1 in ALS and provide a possible explanation for the therapeutic benefits of P2X7 antagonism previously observed in ALS SOD1 G93A mice.

Burnstock oration — purinergic signalling in kidney transplantation - Karen M. Dwyer (Purinergic Signalling, 2022)
Kidney transplantation is the preferred treatment for individuals with kidney failure offering improved quality and quantity of life. Despite significant advancements in short term graft survival, longer term survival rates have not improved greatly mediated in large by chronic antibody mediated rejection. Strategies to reduce the donor kidney antigenic load may translate to improved transplant survival. CD39 on the vascular endothelium and on circulating cells, in particular regulatory T cells (Treg), is upregulated in response to hypoxic stimuli and plays a critical role in regulating the immune response removing proinflammatory ATP and generating anti-inflammatory adenosine. Herein, the role of CD39 in reducing ischaemia–reperfusion injury (IRI) and on Treg within the context of kidney transplantation is reviewed.

Chemical biology-based approaches to study adenosine A2A − dopamine D2 receptor heteromers - Karen J. Gregory; Manuela Jörg (Purinergic Signalling, 2022)

Inhibiting the P2Y13 receptor reduces IL-33 and HMGB1 lung concentrations and inflammatory cell infiltration in a murine model of asthma - Lanxin Li; Stephen J. Fuller (Purinergic Signalling, 2022)

Second meeting of the Australian and New Zealand Purine Club - Carolina Gubert; Reece A. Sophocleous; Ronald Sluyter; Srdjan M. Vlajkovic; Jennie M. E. Cederholm (Purinergic Signalling, 2022)

The P2X7 receptor is a target of p53 and regulates haematopoiesis following radiation-induced genotoxic stress - Peter Cuthbertson; Ronald Sluyter (Purinergic Signalling, 2022)

Adenosine receptor signalling in Alzheimer’s disease - Phuc N. H. Trinh; Jo-Anne Baltos; Shane D. Hellyer; Lauren T. May; Karen J. Gregory (Purinergic Signalling, 2022)
Alzheimer’s disease (AD) is the most common dementia in the elderly and its increasing prevalence presents treatment challenges. Despite a better understanding of the disease, the current mainstay of treatment cannot modify pathogenesis or effectively address the associated cognitive and memory deficits. Emerging evidence suggests adenosine G protein-coupled receptors (GPCRs) are promising therapeutic targets for Alzheimer’s disease. The adenosine A 1 and A 2A receptors are expressed in the human brain and have a proposed involvement in the pathogenesis of dementia. Targeting these receptors preclinically can mitigate pathogenic β-amyloid and tau neurotoxicity whilst improving cognition and memory. In this review, we provide an accessible summary of the literature on Alzheimer’s disease and the therapeutic potential of A 1 and A 2A receptors. Although there are no available medicines targeting these receptors approved for treating dementia, we provide insights into some novel strategies, including allosterism and the targeting of oligomers, which may increase drug discovery success and enhance the therapeutic response.

A2A adenosine receptor activation prevents neutrophil aging and promotes polarization from N1 towards N2 phenotype - Marianna Lovászi; Zoltán H. Németh; Pál Pacher; William C. Gause; Gebhard Wagener; György Haskó (Purinergic Signalling, 2022)

RETRACTED ARTICLE: Lysophosphatidylcholine induces adenosine release from macrophages via TRPM7-mediated mitochondrial activation - Ahmed M. Youssef; Dong-Keun Song (Purinergic Signalling, 2022)

ATP, an attractive target for the treatment of refractory chronic cough - Mengru Zhang; Dominic L. Sykes; Laura R. Sadofsky; Alyn H. Morice (Purinergic Signalling, 2022)
Chronic cough is the most common complaint in respiratory clinics. Most of them have identifiable causes and some may respond to common disease-modifying therapies. However, there are many patients whose cough lacks effective aetiologically targeted treatments or remains unexplained after thorough assessments, which have been described as refractory chronic cough. Current treatments for refractory chronic cough are limited and often accompanied by intolerable side effects such as sedation. In recent years, various in-depth researches into the pathogenesis of chronic cough have led to an explosion in the development of drugs for the treatment of refractory chronic cough. There has been considerable progress in the underlying mechanisms of chronic cough targeting ATP, and ongoing or completed clinical studies have confirmed the promising antitussive efficacy of P2X3 antagonists for refractory cough. Herein, we review the foundation on which ATP target was developed as potential antitussive medications and provide an update on current clinical progresses.

P2 purinergic receptor dysregulation in urologic disease - Janielle P. Maynard; Karen S. Sfanos (Purinergic Signalling, 2022)

Gallic acid modulates purine metabolism and oxidative stress induced by ethanol exposure in zebrafish brain - Samira Leila Baldin; Karolyne de Pieri Pickler; Ana Caroline Salvador de Farias; Henrique Teza Bernardo; Rahisa Scussel; Bárbara da Costa Pereira; Suzielen Damin Pacheco; Eduardo Ronconi Dondossola; Ricardo Andrez Machado-de-Ávila; Almir Gonçalves Wanderley; Eduardo Pacheco Rico (Purinergic Signalling, 2022)

Pleiotropic effects of clopidogrel - Dawn S. Kuszynski; D. Adam Lauver (Purinergic Signalling, 2022)

Functional role of adenosine via KATP channels in cerebral capillary endothelial cells and pericytes - Aali Alqarni; Ashwaq Baghdadi (Purinergic Signalling, 2022)

Purines help determine the gut’s sweet tooth - Jacques Gonzales; Brian D. Gulbransen (Purinergic Signalling, 2022)

P2X receptors in the balance between inflammation and pathogen control in sepsis - Luiz Eduardo Baggio Savio (Purinergic Signalling, 2022)

Ectonucleotidases as bridge between the ATP and adenosine world: reflections on Geoffrey Burnstock - Jürgen Schrader (Purinergic Signalling, 2022)
Historically, mainly by the work of Robert Berne, extracellular adenosine was the first purine compound recognized as an important signaling molecule linking energy metabolism to function by acting on membrane bound receptors. Geoffrey Burnstock by his vision and endurance pioneered the idea that cells release ATP that also acts as an extracellular signaling molecule under many physiological and pathophysiological circumstances. Only later, it was appreciated that extracellular ATP and adenosine are metabolically linked by the activity of several ectoenzymes which critically determine the concentrations of these purines at their respective receptors. In this brief review, I will report some personal recollections on Geoffrey Burnstock and his impressive personality. In addition, I will give a brief overview on our present knowledge of extracellular purine metabolism and its control and will address some still open issues.

May be adenosine an immuno-quorum-sensing signal? - Luca Antonioli; György Haskó (Purinergic Signalling, 2022)

Adenosine A2A receptors blockade attenuates dexamethasone-induced alterations in cultured astrocytes - Daniela Madeira; Liliana Dias; Patrícia Santos; Rodrigo A. Cunha; Paula Agostinho; Paula M. Canas (Purinergic Signalling, 2022)

Purinergic signaling in the peripheral vestibular system - Sung Huhn Kim; Jae Young Choi (Purinergic Signalling, 2022)

NT5E gene and CD38 protein as potential prognostic biomarkers for childhood B-acute lymphoblastic leukemia - Vitória Brum da Silva Nunes; Camila Kehl Dias; Marco Antônio De Bastiani; Mariela Granero Farias; Fabiane Spagnol; Ana Paula Alegretti; Liane Esteves Daudt; Mariana Bohns Michalowski; Ana Maria Oliveira Battastini; Alessandra Aparecida Paz; Fabrício Figueiró (Purinergic Signalling, 2022)

Purinergic activation in response to hemodynamic force directs heart valve development - Xin Cao; Zhichao Zhou (Purinergic Signalling, 2022)

Enlightening activation gating in P2X receptors - Christian Sattler; Klaus Benndorf (Purinergic Signalling, 2022)
P2X receptors are trimeric nonselective cation channels gated by ATP. They assemble from seven distinct subunit isoforms as either homo- or heteromeric complexes and contain three extracellularly located binding sites for ATP. P2X receptors are expressed in nearly all tissues and are there involved in physiological processes like synaptic transmission, pain, and inflammation. Thus, they are a challenging pharmacological target. The determination of crystal and cryo-EM structures of several isoforms in the last decade in closed, open, and desensitized states has provided a firm basis for interpreting the huge amount of functional and biochemical data. Electrophysiological characterization in conjugation with optical approaches has generated significant insights into structure–function relationships of P2X receptors. This review focuses on novel optical and related approaches to better understand the conformational changes underlying the activation of these receptors.

Editorial - Charles Kennedy (Purinergic Signalling, 2022)

Optimized HPLC method to elucidate the complex purinergic signaling dynamics that regulate ATP, ADP, AMP, and adenosine levels in human blood - Carola Ledderose; Eleftheria-Angeliki Valsami; Wolfgang G. Junger (Purinergic Signalling, 2022)

A maestro role of adenosine A2A receptors in GABAergic synapses stabilization during postnatal neuronal maturation - Ana M. Sebastião (Purinergic Signalling, 2022)

A major role for adenosine A2A receptor in the interaction between astrocytes and myelinated neurons: possible implications for the therapy of neurodegenerative disorders - Zaira Boussadia; Valentina Chiodi; Antonio Pazienti; Alberto Martire (Purinergic Signalling, 2022)

Engineered yeast-based eATP precisely controlled system for the treatment of inflammatory bowel disease - Adnan Hassan Tahir; Yong Tang (Purinergic Signalling, 2022)

Purinergic modulation of the immune response to infections - Natalia Eberhardt; Gastón Bergero; Yanina L. Mazzocco Mariotta; M. Pilar Aoki (Purinergic Signalling, 2022)

Selectivity of the P2X3 receptor antagonist Eliapixant, and its potential use in the treatment of endometriosis - Michelle C. Fletcher (Purinergic Signalling, 2022)

P2X7 receptor: the regulator of glioma tumor development and survival - Damian Matyśniak; Vira Chumak; Natalia Nowak; Artur Kukla; Lilya Lehka; Magdalena Oslislok; Paweł Pomorski (Purinergic Signalling, 2022)
P2X7 is an ionotropic nucleotide receptor, forming the cation channel upon ATP stimulation. It can also function as a large membrane pore as well as transmit ATP-dependent signal without forming a channel at all. P2X7 activity in somatic cells is well-known, but remains poorly studied in glioma tumors. The current paper presents the comprehensive study of P2X7 activity in C6 and glioma cell line showing the wide range of effects the receptor has on glioma biology. We observed that P2X7 stimulation boosts glioma cell proliferation and increases cell viability. P2X7 activation promoted cell adhesion, mitochondria depolarization, and reactive oxygen species overproduction in C6 cells. P2X7 receptor also influenced glioma tumor growth in vivo via activation of pro-survival signaling pathways and ATP release. Treatment with Brilliant Blue G, a selective P2X7 antagonist, effectively inhibited glioma tumor development; decreased the expression of negative prognostic cancer markers pro-survival and epithelial-mesenchymal transition (EMT)-related proteins; and modulated the immune response toward glioma tumor in vivo. Finally, pathway-specific enrichment analysis of the microarray data from human patients also showed an upregulation of P2X7 receptor in gliomas from grades I to III. The presented results shed more light on the role of P2X7 receptor in the biology of this disease.

Mono-ADP-ribosylation sites of human CD73 inhibit its adenosine-generating enzymatic activity - Julia Hesse; Mona K. Rosse; Bodo Steckel; Bernhard Blank-Landeshammer; Svenja Idel; Yvonne Reinders; Albert Sickmann; Norbert Sträter; Jürgen Schrader (Purinergic Signalling, 2022)
CD73-derived adenosine plays a major role in damage-induced tissue responses by inhibiting inflammation. Damage-associated stimuli, such as hypoxia and mechanical stress, induce the cellular release of ATP and NAD + and upregulate the expression of the nucleotide-degrading purinergic ectoenzyme cascade, including adenosine-generating CD73. Extracellular NAD + also serves as substrate for mono-ADP-ribosylation of cell surface proteins, which in human cells is mediated by ecto-ADP-ribosyltransferase 1 (ARTC1). Here we explored, whether human CD73 enzymatic activity is regulated by mono-ADP-ribosylation, using recombinant human CD73 in the presence of ARTC1 with etheno-labelled NAD + as substrate. Multi-colour immunoblotting with an anti-etheno-adenosine antibody showed ARTC1-mediated transfer of ADP-ribose together with the etheno label to CD73. HPLC analysis of the enzymatic activity of in vitro-ribosylated CD73 revealed strong inhibition of adenosine generation in comparison to non-ribosylated CD73. Mass spectrometry of in vitro - ribosylated CD73 identified six ribosylation sites. 3D model analysis indicated that three of them (R328, R354, R545) can interfere with CD73 enzymatic activity. Our study identifies human CD73 as target for ARTC1-mediated mono-ADP-ribosylation, which can profoundly modulate its adenosine-generating activity. Thus, in settings with enhanced release of NAD + as substrate for ARTC1, assessment of CD73 protein expression in human tissues may not be predictive of adenosine formation resulting in anti-inflammatory activity.

Involvement of P2X7 receptors in chronic pain disorders - Wen-Jing Ren; Peter Illes (Purinergic Signalling, 2022)
Chronic pain is caused by cellular damage with an obligatory inflammatory component. In response to noxious stimuli, high levels of ATP leave according to their concentration gradient, the intracellular space through discontinuities generated in the plasma membrane or diffusion through pannexin-1 hemichannels, and activate P2X7Rs localized at peripheral and central immune cells. Because of the involvement of P2X7Rs in immune functions and especially the initiation of macrophage/microglial and astrocytic secretion of cytokines, chemokines, prostaglandins, proteases, reactive oxygen, and nitrogen species as well as the excitotoxic glutamate/ATP, this receptor type has a key role in chronic pain processes. Microglia are equipped with a battery of pattern recognition receptors that detect pathogen-associated molecular patterns (PAMPs) such as lipopolysaccharide (LPS) from bacterial infections or danger associated molecular patterns (DAMPs) such as ATP. The co-stimulation of these receptors leads to the activation of the NLRP3 inflammasome and interleukin-1β (IL-1β) release. In the present review, we invite you to a journey through inflammatory and neuropathic pain, primary headache, and regulation of morphine analgesic tolerance, in the pathophysiology of which P2X7Rs are centrally involved. P2X7R bearing microglia and astrocyte-like cells playing eminent roles in chronic pain will be also discussed.

A novel definition and treatment of hyperinflammation in COVID-19 based on purinergic signalling - Djo Hasan; Atsuko Shono; Coenraad K. van Kalken; Peter J. van der Spek; Eric P. Krenning; Toru Kotani (Purinergic Signalling, 2022)
Hyperinflammation plays an important role in severe and critical COVID-19. Using inconsistent criteria, many researchers define hyperinflammation as a form of very severe inflammation with cytokine storm. Therefore, COVID-19 patients are treated with anti-inflammatory drugs. These drugs appear to be less efficacious than expected and are sometimes accompanied by serious adverse effects. SARS-CoV-2 promotes cellular ATP release. Increased levels of extracellular ATP activate the purinergic receptors of the immune cells initiating the physiologic pro-inflammatory immune response. Persisting viral infection drives the ATP release even further leading to the activation of the P2X7 purinergic receptors (P2X7Rs) and a severe yet physiologic inflammation. Disease progression promotes prolonged vigorous activation of the P2X7R causing cell death and uncontrolled ATP release leading to cytokine storm and desensitisation of all other purinergic receptors of the immune cells. This results in immune paralysis with co-infections or secondary infections. We refer to this pathologic condition as hyperinflammation. The readily available and affordable P2X7R antagonist lidocaine can abrogate hyperinflammation and restore the normal immune function. The issue is that the half-maximal effective concentration for P2X7R inhibition of lidocaine is much higher than the maximal tolerable plasma concentration where adverse effects start to develop. To overcome this, we selectively inhibit the P2X7Rs of the immune cells of the lymphatic system inducing clonal expansion of Tregs in local lymph nodes. Subsequently, these Tregs migrate throughout the body exerting anti-inflammatory activities suppressing systemic and (distant) local hyperinflammation. We illustrate this with six critically ill COVID-19 patients treated with lidocaine.

Is the regulation by miRNAs of NTPDase1 and ecto-5’-nucleotidase genes involved with the different profiles of breast cancer subtypes? - Fernanda Cardoso da Silva; Angelo Borges de Melo Neto; Christina Aparecida Martins; Thaís Cunha de Sousa Cardoso; Matheus de Souza Gomes; Thaise Gonçalves de Araújo; Cristina Ribas Fürstenau (Purinergic Signalling, 2022)

Novel possibility for cutaneous melanoma treatment by means of rosmarinic acid action on purinergic signaling - Gilnei Bruno da Silva; Milena Ayumi Yamauchi; Daniela Zanini; Margarete Dulce Bagatini (Purinergic Signalling, 2022)

Mechanisms of ATP release in pain: role of pannexin and connexin channels - Manuel F. Muñoz; Theanne N. Griffith; Jorge E. Contreras (Purinergic Signalling, 2021)
Pain is a physiological response to bodily damage and serves as a warning of potential threat. Pain can also transform from an acute response to noxious stimuli to a chronic condition with notable emotional and psychological components that requires treatment. Indeed, the management of chronic pain is currently an important unmet societal need. Several reports have implicated the release of the neurotransmitter adenosine triphosphate (ATP) and subsequent activation of purinergic receptors in distinct pain etiologies. Purinergic receptors are broadly expressed in peripheral neurons and the spinal cord; thus, purinergic signaling in sensory neurons or in spinal circuits may be critical for pain processing. Nevertheless, an outstanding question remains: what are the mechanisms of ATP release that initiate nociceptive signaling? Connexin and pannexin channels are established conduits of ATP release and have been suggested to play important roles in a variety of pathologies, including several models of pain. As such, these large-pore channels represent a new and exciting putative pharmacological target for pain treatment. Herein, we will review the current evidence for a role of connexin and pannexin channels in ATP release during nociceptive signaling, such as neuropathic and inflammatory pain. Collectively, these studies provide compelling evidence for an important role of connexins and pannexins in pain processing.

An introduction to the special issue “The contribution of pannexin-1, connexins and CALHM ATP-release channels to purinergic signalling” - Charles Kennedy (Purinergic Signalling, 2021)

Quinacrine is not a vital fluorescent probe for vesicular ATP storage - Nao Hasuzawa; Sawako Moriyama; Lixiang Wang; Ayako Nagayama; Kenji Ashida; Yoshinori Moriyama; Masatoshi Nomura (Purinergic Signalling, 2021)

Pharmacological characterization of DPTN and other selective A3 adenosine receptor antagonists - Zhan-Guo Gao; R. Rama Suresh; Kenneth A. Jacobson (Purinergic Signalling, 2021)

Extracellular ectonucleotidases are differentially regulated in murine tissues and human polymorphonuclear leukocytes during sepsis and inflammation - Clarissa B. Haas; Marianna Lovászi; Pál Pacher; Priscila Oliveira de Souza; Julie Pelletier; Rafael Olive Leite; Jean Sévigny; Zoltán Németh; Elizandra Braganhol; György Haskó (Purinergic Signalling, 2021)

Purinergic signaling as a new mechanism underlying physical exercise benefits: a narrative review - Andréia Machado Cardoso; Mauro Nicollas Oliveira Silvério; Sarah Franco Vieira de Oliveira Maciel (Purinergic Signalling, 2021)

The role of Pannexin-1 channels and extracellular ATP in the pathogenesis of the human immunodeficiency virus - Daniela D’Amico; Silvana Valdebenito; Eliseo A. Eugenin (Purinergic Signalling, 2021)

Pannexin 1 channels and ATP release in epilepsy: two sides of the same coin - Elena Dossi; Nathalie Rouach (Purinergic Signalling, 2021)

Recommended tool compounds and drugs for blocking P2X and P2Y receptors - Christa E. Müller; Vigneshwaran Namasivayam (Purinergic Signalling, 2021)
This review article presents a collection of tool compounds that selectively block and are recommended for studying P2Y and P2X receptor subtypes, investigating their roles in physiology and validating them as future drug targets. Moreover, drug candidates and approved drugs for P2 receptors will be discussed.

Purinergic interplay between erythrocytes and platelets in diabetes-associated vascular dysfunction - Zhichao Zhou (Purinergic Signalling, 2021)
Cardiovascular complications in diabetes are the leading causes for high morbidity and mortality. It has been shown that alteration of purinergic signaling contributes to diabetes-associated cardiovascular complications. Red blood cells (RBCs) and platelets play a fundamental role in regulation of oxygen transport and hemostasis, respectively. Of note, these cells undergo purinergic dysfunction in diabetes. Recent studies have established a novel function of RBCs as disease mediators for the development of endothelial dysfunction in type 2 diabetes (T2D). RBC-released ATP is defective in T2D, which has implication for induction of vascular dysfunction by dysregulating purinergic signaling. Platelets are hyperactive in diabetes. ADP-mediated P2Y 1 and P2Y 12 receptor activation contributes to platelet aggregation and targeting P2Y receptors particularly P2Y 12 receptor in platelets is effective for the treatment of cardiovascular events. In contrast to other P2Y 12 receptor antagonists, platelet-targeting drug ticagrelor has potential to initiate purinergic signaling in RBCs for the beneficial cardiovascular outcomes. It is increasingly clear that altered vascular purinergic signaling mediated by various nucleotides and nucleoside contributes to diabetes-associated vascular dysfunction. However, the contribution of complex purinergic networks between RBCs and platelets to the vascular dysfunction in diabetes remains unclear. This study discusses the possible interplay of RBCs and platelets via the purinergic network for diabetes-associated vascular dysfunction.

Substrate binding modes of purine and pyrimidine nucleotides to human ecto-5′-nucleotidase (CD73) and inhibition by their bisphosphonic acid derivatives - Emma Scaletti; Franziska U. Huschmann; Uwe Mueller; Manfred S. Weiss; Norbert Sträter (Purinergic Signalling, 2021)
Human ecto-5-nucleotidase (CD73) is involved in purinergic signalling, which influences a diverse range of biological processes. CD73 hydrolyses AMP and is the major control point for the levels of extracellular adenosine. Inhibitors of CD73 thus block the immunosuppressive action of adenosine, a promising approach for cancer immunotherapy. Interestingly, ADP and ATP are competitive inhibitors of CD73, with the most potent small-molecule inhibitors to date being non-hydrolysable ADP analogues. While AMP is the major substrate of the enzyme, CD73 has been reported to hydrolyse other 5′-nucleoside monophosphates. Based on a fragment screening campaign at the BESSY II synchrotron, we present the binding modes of various deoxyribo- and ribonucleoside monophosphates and of four additional fragments binding to the nucleoside binding site of the open form of the enzyme. Kinetic analysis of monophosphate hydrolysis shows that ribonucleotide substrates are favoured over their deoxyribose equivalents with AMP being the best substrate. We characterised the initial step of AMP hydrolysis, the binding mode of AMP to the open conformation of CD73 and compared that to other monophosphate substrates. In addition, the inhibitory activity of various bisphosphonic acid derivatives of nucleoside diphosphates was determined. Although AMPCP remains the most potent inhibitor, replacement of the adenine base with other purines or with pyrimidines increases the K i value only between twofold and sixfold. On the other hand, these nucleobases offer new opportunities to attach substituents for improved pharmacological properties.

ATP transporters in the joints - Ane Larrañaga-Vera; Miguel Marco-Bonilla; Raquel Largo; Gabriel Herrero-Beaumont; Aránzazu Mediero; Bruce Cronstein (Purinergic Signalling, 2021)
Extracellular adenosine triphosphate (ATP) plays a central role in a wide variety of joint diseases. ATP is generated intracellularly, and the concentration of the extracellular ATP pool is determined by the regulation of its transport out of the cell. A variety of ATP transporters have been described, with connexins and pannexins the most commonly cited. Both form intercellular channels, known as gap junctions, that facilitate the transport of various small molecules between cells and mediate cell–cell communication. Connexins and pannexins also form pores, or hemichannels, that are permeable to certain molecules, including ATP. All joint tissues express one or more connexins and pannexins, and their expression is altered in some pathological conditions, such as osteoarthritis (OA) and rheumatoid arthritis (RA), indicating that they may be involved in the onset and progression of these pathologies. The aging of the global population, along with increases in the prevalence of obesity and metabolic dysfunction, is associated with a rising frequency of joint diseases along with the increased costs and burden of related illness. The modulation of connexins and pannexins represents an attractive therapeutic target in joint disease, but their complex regulation, their combination of gap-junction-dependent and -independent functions, and their interplay between gap junction and hemichannel formation are not yet fully elucidated. In this review, we try to shed light on the regulation of these proteins and their roles in ATP transport to the extracellular space in the context of joint disease, and specifically OA and RA.

UTP is a regulator of in vitro and in vivo angiogenic properties of cardiac adipose–derived stem cells - Marion Vanorlé; Anne Lemaire; Larissa di Pietrantonio; Michael Horckmans; Didier Communi (Purinergic Signalling, 2021)

To inhibit or to boost the ATP/P2RX7 pathway to fight cancer—that is the question - Serena Janho dit Hreich; Jonathan Benzaquen; Paul Hofman; Valérie Vouret-Craviari (Purinergic Signalling, 2021)

Pannexin 1 as a driver of inflammation and ischemia–reperfusion injury - Michael Koval; Aleksandra Cwiek; Thomas Carr; Miranda E. Good; Alexander W. Lohman; Brant E. Isakson (Purinergic Signalling, 2021)

Pannexin 3 channels in health and disease - Brooke L. O’Donnell; Silvia Penuela (Purinergic Signalling, 2021)

Purinergic signaling in tanycytes and its contribution to nutritional sensing - Magdiel Salgado; María Á. García-Robles; Juan C. Sáez (Purinergic Signalling, 2021)

Lack of efficacy of a partial adenosine A1 receptor agonist in neuropathic pain models in mice - Katharina Metzner; Tilman Gross; Annika Balzulat; Gesine Wack; Ruirui Lu; Achim Schmidtko (Purinergic Signalling, 2021)
Previous studies suggest that adenosine A 1 receptors (A 1 R) modulate the processing of pain. The aim of this study was to characterize the distribution of A 1 R in nociceptive tissues and to evaluate whether targeting A 1 R with the partial agonist capadenoson may reduce neuropathic pain in mice. The cellular distribution of A 1 R in dorsal root ganglia (DRG) and the spinal cord was analyzed using fluorescent in situ hybridization. In behavioral experiments, neuropathic pain was induced by spared nerve injury or intraperitoneal injection of paclitaxel, and tactile hypersensitivities were determined using a dynamic plantar aesthesiometer. Whole-cell patch-clamp recordings were performed to assess electrophysiological properties of dissociated DRG neurons. We found A 1 R to be expressed in populations of DRG neurons and dorsal horn neurons involved in the processing of pain. However, administration of capadenoson at established in vivo doses (0.03–1.0 mg/kg) did not alter mechanical hypersensitivity in the spared nerve injury and paclitaxel models of neuropathic pain, whereas the standard analgesic pregabalin significantly inhibited the pain behavior. Moreover, capadenoson failed to affect potassium currents in DRG neurons, in contrast to a full A 1 R agonist. Despite expression of A 1 R in nociceptive neurons, our data do not support the hypothesis that pharmacological intervention with partial A 1 R agonists might be a valuable approach for the treatment of neuropathic pain.

Involvement of ectonucleotidases and purinergic receptor expression during acute Chagas disease in the cortex of mice treated with resveratrol and benznidazole - Mateus Fracasso; Karine Reichert; Nathieli Bianchin Bottari; Anielen Dutra da Silva; Maria Rosa Chitolina Schetinger; Silvia Gonzalez Monteiro; Aleksandro Schafer da Silva (Purinergic Signalling, 2021)

Pro- and anti-inflammatory macrophages express a sub-type specific purinergic receptor profile - J. Merz; A. Nettesheim; S. von Garlen; P. Albrecht; B. S. Saller; J. Engelmann; L. Hertle; I. Schäfer; D. Dimanski; S. König; L. Karnbrock; K. Bulatova; et al. (Purinergic Signalling, 2021)
Extracellular nucleotides act as danger signals that orchestrate inflammation by purinergic receptor activation. The expression pattern of different purinergic receptors may correlate with a pro- or anti-inflammatory phenotype. Macrophages function as pro-inflammatory M1 macrophages (M1) or anti-inflammatory M2 macrophages (M2). The present study found that murine bone marrow-derived macrophages express a unique purinergic receptor profile during in vitro polarization. As assessed by real-time polymerase chain reaction (PCR), Gαs-coupled P1 receptors A2A and A2B are upregulated in M1 and M2 compared to M0, but A2A 15 times higher in M1. The ionotropic P2 receptor P2X 5 is selectively upregulated in M1- and M2-polarized macrophages. P2X 7 is temporarily expressed in M1 macrophages. Metabotropic P2Y receptors showed a distinct expression profile in M1 and M2-polarized macrophages: Gαq coupled P2Y 1 and P2Y 6 are exclusively upregulated in M2, whereas Gαi P2Y 13 and P2Y 14 are overexpressed in M1. This consequently leads to functional differences between M1 and M2 in response to adenosine di-phosphate stimulation (ADP): In contrast to M1, M2 showed increased cytoplasmatic calcium after ADP stimulation. In the present study we show that bone marrow-derived macrophages express a unique repertoire of purinergic receptors. We show for the first time that the repertoire of purinergic receptors is highly flexible and quickly adapts upon pro- and anti-inflammatory macrophage differentiation with functional consequences to nucleotide stimulation.

ENTPD5 splice variants: novel players in cancer? - Francesca Arruga (Purinergic Signalling, 2021)

Deletion of CD73 increases exercise power in mice - Aderbal S. Aguiar; Ana Elisa Speck; Paula M. Canas; Rodrigo A. Cunha (Purinergic Signalling, 2021)

Maria Teresa Miras Portugal (1948–2021): in memoriam - Herbert Zimmermann; Simon C. Robson; Esmerilda Garcia Delicado; Maria Abbracchio; Francesco Di Virgilio; Alexej Verkhratzky; Carlos Matute (Purinergic Signalling, 2021)

Optical control of purinergic signaling - Tao Wang; Henning Ulrich; Alexey Semyanov; Peter Illes; Yong Tang (Purinergic Signalling, 2021)
Purinergic signaling plays a pivotal role in physiological processes and pathological conditions. Over the past decades, conventional pharmacological, biochemical, and molecular biology techniques have been utilized to investigate purinergic signaling cascades. However, none of them is capable of spatially and temporally manipulating purinergic signaling cascades. Currently, optical approaches, including optopharmacology and optogenetic, enable controlling purinergic signaling with low invasiveness and high spatiotemporal precision. In this mini-review, we discuss optical approaches for controlling purinergic signaling and their applications in basic and translational science.

ENTPD5: identification of splicing variants and their impact on cancer survival - Rafael Paschoal de Campos; Marcia Rosângela Wink; Guido Lenz (Purinergic Signalling, 2021)

The ATP/P2X7 axis is a crucial regulator of leukemic initiating cells proliferation and homing and an emerging therapeutic target in acute myeloid leukemia - Anna Pegoraro; Elena Adinolfi (Purinergic Signalling, 2021)

BAC transgenic mice to study the expression of P2X2 and P2Y1 receptors - Marcus Grohmann; Michaela Schumacher; Janka Günther; Stefan M. Singheiser; Tanja Nußbaum; Florian Wildner; Zoltan Gerevich; Ronald Jabs; Daniela Hirnet; Christian Lohr; Peter Illes; Günther Schmalzing; et al. (Purinergic Signalling, 2021)
Extracellular purines are important signaling molecules involved in numerous physiological and pathological processes via the activation of P2 receptors. Information about the spatial and temporal P2 receptor (P2R) expression and its regulation remains crucial for the understanding of the role of P2Rs in health and disease. To identify cells carrying P2X2Rs in situ, we have generated BAC transgenic mice that express the P2X2R subunits as fluorescent fusion protein (P2X2-TagRFP). In addition, we generated a BAC P2Y 1 R TagRFP reporter mouse expressing a TagRFP reporter for the P2RY1 gene expression. We demonstrate expression of the P2X2R in a subset of DRG neurons, the brain stem, the hippocampus, as well as on Purkinje neurons of the cerebellum. However, the weak fluorescence intensity in our P2X2R-TagRFP mouse precluded tracking of living cells. Our P2Y 1 R reporter mice confirmed the widespread expression of the P2RY1 gene in the CNS and indicate for the first time P2RY1 gene expression in mouse Purkinje cells, which so far has only been described in rats and humans. Our P2R transgenic models have advanced the understanding of purinergic transmission, but BAC transgenic models appeared not always to be straightforward and permanent reliable. We noticed a loss of fluorescence intensity, which depended on the number of progeny generations. These problems are discussed and may help to provide more successful animal models, even if in future more versatile and adaptable nuclease-mediated genome-editing techniques will be the methods of choice.

Structural basis for the functional properties of the P2X7 receptor for extracellular ATP - Lin-Hua Jiang; Emily A. Caseley; Steve P. Muench; Sébastien Roger (Purinergic Signalling, 2021)
The P2X7 receptor, originally known as the P2Z receptor due to its distinctive functional properties, has a structure characteristic of the ATP-gated ion channel P2X receptor family. The P2X7 receptor is an important mediator of ATP-induced purinergic signalling and is involved the pathogenesis of numerous conditions as well as in the regulation of diverse physiological functions. Functional characterisations, in conjunction with site-directed mutagenesis, molecular modelling, and, recently, structural determination, have provided significant insights into the structure–function relationships of the P2X7 receptor. This review discusses the current understanding of the structural basis for the functional properties of the P2X7 receptor.

Autocrine and paracrine purinergic signaling in the most lethal types of cancer - M. Reyna-Jeldes; M. Díaz-Muñoz; J. A. Madariaga; C. Coddou; F. G. Vázquez-Cuevas (Purinergic Signalling, 2021)

Adenosine A2A receptor null chondrocyte transcriptome resembles that of human osteoarthritic chondrocytes - Cristina M. Castro; Carmen Corciulo; Benjamin Friedman; Zhi Li; Samson Jacob; David Fenyo; Bruce N. Cronstein (Purinergic Signalling, 2021)

Cystic fibrosis improves COVID-19 survival and provides clues for treatment of SARS-CoV-2 - Edward H. Abraham; Guido Guidotti; Eliezer Rapaport; David Bower; Jack Brown; Robert J. Griffin; Andrew Donnelly; Ellen D. Waitzkin; Kenon Qamar; Mark A. Thompson; Sukumar Ethirajan; Kent Robinson (Purinergic Signalling, 2021)
Systemic pools of ATP are elevated in individuals homozygous for cystic fibrosis (CF) as evidenced by elevated blood and plasma ATP levels. This elevated ATP level seems to provide benefit in the presence of advanced solid tumors (Abraham et al., Nature Medicine 2(5):593–596, 1996). We published in this journal a paper showing that IV ATP can elevate the depleted ATP pools of advanced cancer patients up to levels found in CF patients with subsequent clinical, biochemical, and quality of life (QOL) improvements (Rapaport et al., Purinergic Signalling 11(2): 251–262, 2015). We hypothesize that the elevated ATP levels seen in CF patients may be benefiting CF patients in another way: by improving their survival after contracting COVID-19. We discuss here the reasoning behind this hypothesis and suggest how these findings might be applied clinically in the general population.

Enhanced expression of P2X4 purinoceptors in pyramidal neurons of the rat hippocampal CA1 region may be involved ischemia-reperfusion injury - Zhenghua Xiang; Xin Jiang; Rihui Ji; Hongbin Yuan (Purinergic Signalling, 2021)

The role of the bladder urothelium as a chemical-neural transducer via purinergic signalling in the rapid defence against bacterial infection - Basu Chakrabarty (Purinergic Signalling, 2021)

Acupuncture modulates extracellular ATP levels in peripheral sensory nervous system during analgesia of ankle arthritis in rats - Dan Shen; Ya-Wen Zheng; Di Zhang; Xue-Yong Shen; Li-Na Wang (Purinergic Signalling, 2021)

Neutrophils: fast and furious—the nucleotide pathway - Dominique S. Rubenich; Priscila O. de Souza; Natalia Omizzollo; Gabriela S. Lenz; Jean Sevigny; Elizandra Braganhol (Purinergic Signalling, 2021)

Consequences of an obesogenic diet can be prevented by knockout of P2Y6 purinergic receptor in mice - Kayleigh E. Goddard (Purinergic Signalling, 2021)

The role of peripheral adenosine receptors in glutamate-induced pain nociceptive behavior - S. J. Macedo-Júnior; F. P. Nascimento; M. Luiz-Cerutti; A. R. S. Santos (Purinergic Signalling, 2021)

Bone phenotype of P2X4 receptor knockout mice: implication of a P2X7 receptor mutation? - Maria Ellegaard; Tanja Hegner; Ming Ding; Lauriane Ulmann; Niklas Rye Jørgensen (Purinergic Signalling, 2021)

Correction to: The history of the purine Club: a tribute to prof. Geoffrey Burnstock - Maria P. Abbracchio (Purinergic Signalling, 2021)

Effects of intranasal guanosine administration on brain function in a rat model of ischemic stroke - Gabriel C. Müller; Samanta O. Loureiro; Letícia F. Pettenuzzo; Roberto F. Almeida; Evandro Y. Ynumaru; Pedro A. Guazzelli; Fabíola S. Meyer; Mayara V. Pasquetti; Marcelo Ganzella; Maria Elisa Calcagnotto; Diogo O. Souza (Purinergic Signalling, 2021)

P2X7: a receptor with a split personality that raises new hopes for anti-cancer therapy - Alba Clara Sarti; Valentina Vultaggio-Poma; Francesco Di Virgilio (Purinergic Signalling, 2021)

Pancreatic cancer immune evasion mechanisms: the immunosuppressive role of P2RX1-negative neutrophils - Valentina Audrito (Purinergic Signalling, 2021)

Targeting P2 receptors in purinergic signaling: a new strategy of active ingredients in traditional Chinese herbals for diseases treatment - Xiaopeng Ai; Xing Dong; Ying Guo; Peng Yang; Ya Hou; Jinrong Bai; Sanyin Zhang; Xiaobo Wang (Purinergic Signalling, 2021)