Distinguishing cytotoxicity-associated and direct immunomodulatory effects of enniatins and beauvericin in human immune and intestinal cells

Abstract

Enniatins (ENNs) and beauvericin (BEA) are emerging Fusarium mycotoxins frequently detected in cereals and processed foods, raising concerns about their toxic potential. These cyclic hexadepsipeptides exert cytotoxic effects by disrupting ionic homeostasis and accumulating in lipid membranes. Although ENNs and BEA modulate pathways such as NF-κB and MAPK, their direct immunomodulatory effects remain poorly characterized. This study investigates their impact on inflammation, cytokine regulation, and metabolic activity in human immune (THP-1 Lucia™ monocytes) and intestinal (HCEC-1CT, Caco-2) cell models, including effects of phase I metabolites generated by S9 mix preincubation. In THP-1 Lucia™ monocytes, all tested ENNs (2.5-5 µM) and BEA (5 µM) suppressed lipopolysaccharide-induced NF-κB activity only at cytotoxic concentrations, suggesting that immunosuppressive effects are secondary to cell damage. Pre-treatment with rat liver S9 mix mitigated cytotoxicity and attenuated NF-κB suppression. In intestinal cells, ENNs and BEA reduced TNF-α transcription in non-tumorigenic HCEC-1CT but not in tumorigenic Caco-2 cells, indicating cell-type-specific responses. These findings emphasize the context-dependent immunotoxicity of ENNs and BEA and underscore the need to distinguish between direct immunomodulation and secondary effects of reduced cell viability. While broader immune disruption appears limited to toxic concentrations, TNF-α suppression in non-tumorigenic intestinal cells may pose a health concern.

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