NRF2/PGC-1α-mediated mitochondrial biogenesis contributes to T-2 toxin-induced toxicity in human neuroblastoma SH-SY5Y cells

Abstract

The T-2 toxin is a highly toxic trichothecene mycotoxin that would cause serious toxicity in humans and animals. Recent studies suggest that the central nervous system (CNS) is susceptible to T-2 toxin, which can easily cross the blood-brain barrier, accumulate in brain tissues, and cause neurotoxicity. The growing evidence indicates that oxidative damage and mitochondrial dysfunction play a critical role in T-2 toxin-induced neurotoxicity, but the mechanisms are still poorly understood. Our present study showed that T-2 toxin decreased cell viability and increased lactate dehydrogenase leakage in human neuroblastoma SH-SY5Y cells in a concentration- and time-dependent manner. T-2 toxin elicited prominent oxidative stress and mitochondrial dysfunction, as evidenced by the promotion of cellular reactive oxygen species generation, disruption of the mitochondrial membrane potential, depletion of glutathione and reduction of the cellular ATP content. T-2 toxin impaired mitochondrial biogenesis, including decreased mitochondrial DNA copy number and affected the nuclear factor erythroid 2 related factor 2 (NRF2) / peroxisome proliferator-activated receptor γ coactivator 1 alpha (PGC-1α) pathway by upregulating NRF2 mRNA and protein expression while inhibiting the expression of PGC-1α, nuclear respiratory factor (NRF1) and mitochondrial transcription factor A (TFAM). NRF2 knockdown was found to significantly exacerbate T-2 toxin-induced cytotoxicity, oxidative stress, and mitochondrial dysfunction, as well as aggravate mitochondrial biogenesis impairment. NRF2 knockdown compromised T-2 toxin-induced upregulation of NRF2, but augmented the inhibition of PGC-1α, NRF1, and TFAM by T-2 toxin. Taken together, these findings suggest that T-2 toxin-induced oxidative stress and mitochondrial dysfunction in SH-SY5Y cells, at least in part by, NRF2/PGC-1α pathway-mediated mitochondrial biogenesis.

Keywords: Mitochondrial biogenesis; NRF2/PGC-1α; Neurotoxicity; Oxidative stress; T-2 toxin.