Environ Pollut. 2025 Dec 19. pii: S0269-7491(25)01936-0. [Epub ahead of print]
127562
Trifloxystrobin (TFX), a potent inhibitor of complex III in the mitochondrial respiratory chain, is a widely used strobilurin fungicide whose neurotoxic mechanisms remain poorly defined. This study investigated the molecular pathways underlying TFX-induced toxicity in human SH-SY5Y neuronal-like neuroblastoma cells, with particular emphasis on oxidative stress, mitochondrial dysfunction, and activation of the Integrated Stress Response (ISR). TFX exposure (24 h) exhibited an IC50 of approximately 100 μM, induced G0/G1 cell cycle arrest, and triggered mitochondria-mediated apoptosis, as evidenced by loss of mitochondrial membrane potential (ΔΨm), Bax activation, cytochrome c release, DNA fragmentation, phosphatidylserine exposure, and caspase-3 activation. These effects were accompanied by increased mitochondrial superoxide levels and decreased ATP production, indicating profound mitochondrial impairment. Pretreatment with N-acetylcysteine (NAC) markedly restored cell viability, reduced ROS accumulation, prevented ΔΨm dissipation, and diminished apoptotic damage. Mechanistically, TFX activated the ISR through the OMA1-DELE1-HRI mitochondrial stress signaling axis, as confirmed by loss-of-function experiments targeting these proteins. Importantly, both NAC and the ISR inhibitor ISRIB (Integrated Stress Response InhiBitor) significantly attenuated ISR activation and the resulting apoptosis, demonstrating that oxidative stress serves as an upstream trigger for ISR engagement and cell death. Collectively, these findings reveal that TFX induces oxidative stress-dependent activation of the OMA1-DELE1-HRI ISR pathway, linking mitochondrial dysfunction to apoptosis in human neuroblastoma cells. To our knowledge, this is the first report identifying ISR activation as a mechanistic component of strobilurin fungicide-induced neurotoxicity.
Keywords: ISR; SH-SY5Y cells; Trifloxystrobin; apoptosis; oxidative stress