Specific inhibition of hypoxia inducible factor 1 exaggerates cell injury induced by in vitro ischemia through deteriorating cellular redox environment.
Specific inhibition of hypoxia inducible factor 1 exaggerates cell injury induced by in vitro ischemia through deteriorating cellular redox environment.
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DOI：
10.1111/j.1471-4159.2009.05877.x
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发表时间：
2009-03
影响因子：
4.7
通讯作者：
Shi H
中科院分区：
文献类型：
--
作者：
Guo S;Miyake M;Liu KJ;Shi H
低氧诱导因子1（Hypoxia inducible factor 1，HIF-1）在细胞缺氧损伤中起重要作用。然而，在缺血条件下HIF-1调节细胞存活的机制仍不完全清楚。氧化还原状态对于决定细胞存活、死亡和分化至关重要。我们研究了抑制HIF-1对暴露于缺氧或氧和葡萄糖剥夺（OGD）的SH-SY 5 Y细胞中细胞氧化还原状态的影响，并结合细胞死亡分析。我们的研究结果表明，通过HIF-1α特异性siRNA转染抑制HIF-1α表达增加了活性氧的产生，并将细胞转化为缺氧或OGD暴露下更氧化的环境（低GSH/GSSG比，低NADPH水平）。在缺氧/OGD暴露后，与未转染的细胞相比，siRNA转染的细胞中的细胞死亡显著增加。相反，通过去铁胺（一种金属螯合剂和羟化酶抑制剂）增加HIF-1α表达，诱导了更还原的环境（高GSH/GSSG比率，高NADPH水平）并减少了细胞死亡。进一步的研究表明，HIF-1不仅调节葡萄糖转运蛋白-1的表达，而且还调节戊糖磷酸途径的关键酶，如葡萄糖-6-磷酸脱氢酶和6-磷酸葡萄糖酸脱氢酶。这些酶通过产生NADPH（细胞中的主要还原剂）在维持细胞氧化还原稳态中是重要的。此外，过氧化氢酶显着减少细胞死亡的siRNA转染细胞诱导的缺氧和OGD。这些结果表明，通过HIF-1维持细胞氧化还原状态保护细胞免受缺氧和缺血介导的损伤。
Hypoxia inducible factor 1 (HIF-1) has been suggested to play a critical role in the fate of cells exposed to hypoxic stress. However, the mechanism of HIF-1-regulated cell survival is still not fully understood in ischemic conditions. Redox status is critical for decisions of cell survival, death and differentiation. We investigated the effects of inhibiting HIF-1 on cellular redox status in SH-SY5Y cells exposed to hypoxia or oxygen and glucose deprivation (OGD), coupled with cell death analyses. Our results demonstrated that inhibiting HIF-1α expression by HIF-1α specific siRNA transfection increased reactive oxygen species generation, and transformed the cells to more oxidizing environments (low GSH/GSSG ratio, low NADPH level) under either hypoxic or OGD exposure. Cell death increased dramatically in the siRNA transfected cells, compared to non-transfected cells after hypoxic/OGD exposures. In contrast, increasing HIF-1α expression by desferrioxamine, a metal chelator and hydroxylase inhibitor, induced a more reducing environment (high GSH/GSSG ratio, high NADPH level) and reduced cell death. Further studies showed that HIF-1 regulated not only glucose transporter-1 expression, but also the key enzymes of the pentose phosphate pathway such as glucose-6-phosphate dehydrogenase and 6-phosphogluconate dehydrogenase. These enzymes are important in maintaining cellular redox homeostasis by generating NADPH, the primary reducing agent in cells. Moreover, catalase significantly decreased cell death in the siRNA-transfected cells induced by hypoxia and OGD. These results suggest that maintenance of cellular redox status by HIF-1 protects cells from hypoxia and ischemia mediated injuries.
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影响因子：
5.3
作者：
Kirkland, RA;Franklin, JL
通讯作者：
Franklin, JL
DOI：
10.1073/pnas.97.18.10242
发表时间：
2000-08-29
影响因子：
11.1
作者：
Jin, KL;Mao, XO;Greenberg, DA
通讯作者：
Greenberg, DA
DOI：
10.1097/00004647-199603000-00001
发表时间：
1996-03-01
影响因子：
6.3
作者：
Lawrence, MS;Sun, GH;Steinberg, GK
通讯作者：
Steinberg, GK
影响因子：
7.3
作者：
Fernandez-Gomez, FJ;Galindo, MF;Jordán, J
通讯作者：
Jordán, J
影响因子：
5.3
作者：
Helton, R;Cui, J;Barlow, C
通讯作者：
Barlow, C