敲低IOP1基因的表达诱导原代HUVECs细胞的早老

Knockdown of IOP1 Induces Premature Senescence in Primary HUVECs

唯铁脱氢酶样蛋白1(iron-only hydrogenase-like protein 1,IOP1)是细胞质铁硫簇蛋白组装机器(cytosolic iron-sulfur protein assembly, CIA)的1个成员。IOP1是缺氧诱导转录因子(hypoxia-inducible transcription factor 1, HIF-1)负调控因子。我们之前的研究发现,在二倍体酿酒酵母中,缺失NAR1基因(IOP1在酵母中的同源基因)的1个拷贝,会增加酵母细胞对氧化应激的敏感性,同时缩短酵母细胞的复制寿命,但其中的分子机制仍不清楚。最近我们发现,在晚期传代的原代人脐静脉内皮细胞(HUVECs)中,IOP1的蛋白质表达水平显著高于早期传代的人脐静脉内皮细胞。这一发现暗示,IOP1很可能在细胞衰老过程中存在一定的作用,故对此展开深入研究。本文在原代HUVECs细胞中转染靶向IOP1基因的siRNA,降低IOP1基因的表达水平,进而检测细胞衰老的相关指标。结果显示:降低IOP1基因的表达可以诱导原代HUVECs细胞出现早老表型,细胞增殖能力下降(P<0.01),细胞中的ROS水平升高(P<0.01),DNA损伤加剧(P<0.05),细胞线粒体呼吸能力减弱(P<0.01),细胞周期阻滞在G1期(P<0.01)。这些研究结果表明,IOP1在哺乳动物细胞的氧化应激和衰老过程中发挥重要作用。这对于干预哺乳动物细胞衰老的研究具有一定的提示作用。

Iron-only hydrogenase-like protein 1( IOP1) is a component of the cytosolic iron-sulfur protein assembly( CIA) machinery. IOP1 has been suggested to be a negative regulator of the hypoxiainducible transcription factor 1( HIF-1). We previously reported that loss of one copy of NAR1( the yeast homolog of IOP1) in diploid yeast cells leads to increased sensitivity to oxidative stress and decreased replicative lifespan,however,the underlying mechanism is still unclear. Recently,we found that the IOP1 protein was upregulated in late-passaged primary human umbilical vein endothelial cells( HUVECs) compared with that in early-passaged primary HUVECs,which indicated a potential association of IOP1 with cellular senescence. The aim of this study was to investigate the potential function of IOP1 in aging in mammalian cells. The primary HUVECs were transfected with IOP1-specific siRNA and subjected to premature senescence assays. We found that IOP1 knockdown leads to premature senescence and decreased cell proliferative ability( P < 0. 01) in primary HUVECs. Further studies revealed that downregulation of IOP1 resulted in upregulated ROS levels( P < 0. 01),enhanced DNA damage( P<0. 05) and decreased mitochondrial respiration( P<0. 01) along with cell cycle arrest at the G1 phase( P < 0. 01). Thus,the current study highlights involvement of IOP1 in the oxidative stress response and aging process in mammalian cells,which will be informative for interventional research on aging.