曲霉毒素A(OTA),一种以肾毒性作用而闻名的次级真菌代谢产物,在各种饲料和食品中普遍存在。我们最近的研究表明,OTA诱导的肾毒性与人近端小管上皮起源的肾2(HK-2)细胞中Sigma-1受体(Sig-1R)介导的线粒体途径凋亡有关。然而,Sig-1R对OTA诱导的肾毒性的贡献,涉及其他形式的调节细胞死亡,比如铁中毒,仍未探索。在这次调查中,细胞活力,丙二醛(MDA)水平,谷胱甘肽(GSH)水平,评估用OTA和/或Ferrostatin-1/盐酸布拉卡米汀/BD1063二盐酸盐处理的HK-2细胞中的蛋白表达。结果表明,用1μMOTA处理24h通过抑制Sig-1R显著诱导铁凋亡,随后促进核受体共激活因子4(NCOA4),长链脂肪酸辅酶A连接酶4(ACSL4),花生四烯酸5-脂氧合酶(ALOX5),自噬蛋白5(ATG5),和ATG7,抑制铁蛋白重链(FTH1),溶质载体家族7成员11(SLC7A11/xCT),谷胱甘肽过氧化物酶4(GPX4),过氧化物酶6(PRDX6),和铁凋亡抑制蛋白1(FSP1),降低GSH水平,MDA水平升高(P<0.05)。总之,OTA通过抑制Sig-1R诱导铁凋亡,随后促进铁蛋白吞噬,抑制GPX4/FSP1抗氧化系统,降低GSH水平,并最终增加体外脂质过氧化水平。
Ochratoxin A (OTA), a secondary fungal metabolite known for its nephrotoxic effects, is prevalent in various feeds and food items. Our recent study suggests that OTA-induced nephrotoxicity is linked to the Sigma-1 receptor (Sig-1R)-mediated mitochondrial pathway apoptosis in human proximal tubule epithelial-originated kidney-2 (HK-2) cells. However, the contribution of Sig-1R to OTA-induced nephrotoxicity involving other forms of regulated cell death, such as ferroptosis, remains unexplored. In this investigation, cell viability, malondialdehyde (MDA) levels, glutathione (GSH) levels, and protein expressions in HK-2 cells treated with OTA and/or Ferrostatin-1/blarcamesine hydrochloride/BD1063 dihydrochloride were assessed. The results indicate that a 24 h-treatment with 1 μM OTA significantly induces ferroptosis by inhibiting Sig-1R, subsequently promoting nuclear receptor coactivator 4 (NCOA4), long-chain fatty acid-CoA ligase 4 (ACSL4), arachidonate 5-lipoxygenase (ALOX5), autophagy protein 5 (ATG5), and ATG7, inhibiting ferritin heavy chain (FTH1), solute carrier family 7 member 11 (SLC7A11/xCT), glutathione peroxidase 4 (GPX4), peroxiredoxin 6 (PRDX6), and ferroptosis suppressor protein 1 (FSP1), reducing GSH levels, and increasing MDA levels (P < 0.05). In conclusion, OTA induces ferroptosis by inhibiting Sig-1R, subsequently promoting ferritinophagy, inhibiting GPX4/FSP1 antioxidant systems, reducing GSH levels, and ultimately increasing lipid peroxidation levels in vitro.