缺氧通过HIF-1α-IGFBP-3依赖性信号传导抑制心肌存活途径,并主要通过FoxO3a诱导的BNIP3表达增强心肌细胞自噬和凋亡作用。
Hypoxia suppresses myocardial survival pathway through HIF-1α-IGFBP-3-dependent signaling and enhances cardiomyocyte autophagic and apoptotic effects mainly via FoxO3a-induced BNIP3 expression.
作者信息
Feng Chih-Chung, Lin Chien-Chung, Lai Yi-Ping, Chen Tung-Sheng, Marthandam Asokan Shibu, Lin Jing-Ying, Lin Kuan-Ho, Viswanadha Vijaya Padma, Kuo Wei-Wen, Huang Chih-Yang
机构信息
a Graduate Institute of Clinical Medical Science, Graduate Institute of Basic Medical Science, China Medical University , Taichung , Taiwan .
b Orthopaedic Department, Armed Forces General Hospital , Taichung , Taiwan .
出版信息
Growth Factors. 2016 Aug;34(3-4):73-86. doi: 10.1080/08977194.2016.1191480. Epub 2016 Jul 1.
The HIF-1α transcriptional factor and the BH-3 only protein BNIP3 are known to play fundamental roles in response to hypoxia. The objective of this research is to investigate the molecular mechanisms and the correlation of HIF-1α, BNIP3 and IGFBP-3 in hypoxia-induced cardiomyocytes injuries. Heart-derived H9c2 cells and neonatal rat ventricular myocytes (NRVMs) were incubated in normoxic or hypoxic conditions. Hypoxia increased HIF-1α expression and activated the downstream BNIP3 and IGFBP-3 thereby triggered mitochondria-dependent apoptosis. Moreover, IGF1R/PI3K/Akt signaling was attenuated by HIF-1α-dependent IGFBP-3 expression to enhance hypoxia-induced apoptosis. Autophagy suppression with 3-methyladenine or siATG5 or siBeclin-1 significantly decreased myocardial apoptosis under hypoxia. Knockdown of FoxO3a or BNIP3 significantly abrogated hypoxia-induced autophagy and mitochondria-dependent apoptosis. Moreover, prolonged-hypoxia induced HIF-1α stimulated BNIP3 and enhanced IGFBP-3 activation to inhibit IGF1R/PI3K/Akt survival pathway and mediate mitochondria-dependent cardiomyocyte apoptosis. HIF-1α and FoxO3a blockage are sufficient to annul the change of excessive hypoxia of hearts.
已知缺氧诱导因子-1α(HIF-1α)转录因子和仅含BH-3结构域的蛋白BNIP3在缺氧反应中发挥重要作用。本研究的目的是探讨缺氧诱导心肌细胞损伤过程中HIF-1α、BNIP3和胰岛素样生长因子结合蛋白-3(IGFBP-3)的分子机制及其相关性。将心脏来源的H9c2细胞和新生大鼠心室肌细胞(NRVMs)置于常氧或缺氧条件下培养。缺氧增加了HIF-1α的表达并激活了下游的BNIP3和IGFBP-3,从而引发线粒体依赖性凋亡。此外,HIF-1α依赖性IGFBP-3的表达减弱了IGF1R/PI3K/Akt信号传导,从而增强了缺氧诱导的凋亡。用3-甲基腺嘌呤或小干扰RNA(si)ATG5或siBeclin-1抑制自噬可显著降低缺氧条件下的心肌细胞凋亡。敲低叉头框O3a(FoxO3a)或BNIP3可显著消除缺氧诱导的自噬和线粒体依赖性凋亡。此外,长时间缺氧诱导HIF-1α刺激BNIP3并增强IGFBP-3的激活,从而抑制IGF1R/PI3K/Akt生存途径并介导线粒体依赖性心肌细胞凋亡。阻断HIF-1α和FoxO3a足以消除心脏过度缺氧的变化。