支链氨基酸氨基转移酶1通过核因子E2相关因子2调节缺氧/复氧损伤相关的心肌细胞铁死亡

Branched-chain amino acid aminotransferase-1 regulates hypoxia/reoxygenation-associated cardiomyocyte ferroptosis via a nuclear factor erythroid 2-related factor-2-dependent manner

目的研究支链氨基酸转移酶(branched-chain amino acid aminotransferase 1,BCAT1)调节心肌细胞铁死亡和缺氧/复氧损伤的作用及机制。方法分离Sprague Dawley乳鼠心室肌细胞(neonatal rat ventricular myocytes,NRVMs)并培养。利用腺病毒载体转染NRVMs分别敲低或过表达BCAT1后给予NRVMs缺氧/复氧(hypoxia/reoxygenation,H/R)损伤或给予Erastin诱导其铁死亡。给予核因子E2相关因子2(nuclear factor erythroid 2-related factor-2,NRF2)特异性抑制剂ML385探讨NRF2在BCAT1调节NRVMs铁死亡中的作用。结果敲低BCAT1表达加重H/R诱导的NRVMs死亡和脂质过氧化,而敲低BCAT1加重损伤的现象可被铁死亡抑制剂Ferr-1基本消除。过表达BCAT1可以减轻H/R和Erastin诱导的心肌细胞死亡和脂质过氧化。过表达BCAT1显著上调NRF2蛋白表达和下游抗氧化应激基因Ho-1、Nqo-1和Trx-1 m RNA表达。给予NRF2特异性抑制剂显著地抑制了BCAT1过表达对H/R损伤和铁死亡的保护作用(均P<0.05)。结论BCAT1通过NRF2调节心肌细胞铁死亡,这可能是其影响心肌细胞H/R损伤的关键机制。

AIM To investigate the role and mechanism of branched-chain amino acid aminotransferase 1(BCAT1)in regulating cardiomyocyte ferroptosis and hypoxia/reoxygenation injury.METHODS Neonatal rat ventricular myocytes(NRVMs)were routinely isolated from neonatal Sprague-Dawley rats and were in vitro cultured.NRVMs were transfected with adenovirus vectors overexpressing or silencing BCAT1 and then were subjected to hypoxia/reoxygenation(H/R)or the ferroptosis inducer,Erastin.ML385,a specific inhibitor of nuclear factor E2-related factor-2(NRF2),was administered into NRVMs to explore the involvement of NRF2 in cardiomyocyte ferroptosis regulated by BCAT1.RESULTS BCAT1 silencing exacerbated H/R-induced NRVM death,a phenomenon basically eliminated by the ferroptosis inhibitor Ferr-1.Over-expression of BCAT1 significantly ameliorated H/R-induced cell death and Erastin-induced ferroptosis.BCAT1 over-expression significantly increased the protein abundance of NRF2 and up-regulated the mRNA levels of NRF2 downstream gene Ho-1,Nqo-1 and Trx-1.Inhibition of NRF2 by ML385 blocked the protective effect of BCAT1 over-expression against H/R injury and ferroptosis(all P<0.05).CONCLUSION BCAT1 regulates cardiomyocyte ferroptosis via a NRF2-dependent manner,which might be a key mechanism of BCAT1’s effect on H/R-induced cardiomyocyte injury.