NADPH oxidase 4 promotes cardiac microvascular angiogenesis after hypoxia/reoxygenation in vitro

详细信息    查看全文

• 作者：Jinyi Wang¹ ; Zhibo Hong¹ ; Chao Zeng¹ ; Qiujun Yu ; ^{yuqiujun@gmail.com" class="auth_mail} ; Haichang Wang ; ^{wanghc@fmmu.edu.cn" class="auth_mail}
• 关键词：CMEC ; cardiac microvascular endothelial cell ; HIF-1伪 ; hypoxia-inducible factor 1伪 ; H/R ; hypoxia/reoxygenation ; Nox ; NADPH oxidase ; PHD ; prolyl hydroxylase domain-containing protein ; ROS ; reactive oxygen species ; siRNA ; small interfering RNA ; VEGF ; vascular endothelial growth factor
• 刊名：Free Radical Biology and Medicine
• 出版年：April, 2014
• 年：2014
• 卷：69
• 期：Complete
• 页码：278-288
• 全文大小：6194 K

文摘

Microvascular endothelial cell dysfunction plays a key role in myocardial ischemia/reperfusion (I/R) injury, wherein reactive oxygen species (ROS)-dependent signaling is intensively involved. However, the roles of the various ROS sources remain unclear. This study sought to investigate the role of NADPH oxidase 4 (Nox4) in the cardiac microvascular endothelium in response to I/R injury. Adult rat cardiac microvascular endothelial cells (CMECs) were isolated and subjected to hypoxia/reoxygenation (H/R). Our results showed that Nox4 was highly expressed in CMECs, was significantly increased at both mRNA and protein levels after H/R injury, and contributed to H/R-stimulated increase in Nox activity and ROS generation. Downregulation of Nox4 by small interfering RNA transfection did not affect cell viability or ROS production under normoxia, but exacerbated H/R injury as evidenced by increased apoptosis and inhibited cell survival, migration, and angiogenesis after H/R. Nox4 inhibition also increased prolyl hydroxylase 2 (PHD2) expression and blocked H/R-induced increases in HIF-1伪 and VEGF expression. Pretreatment with DMOG, a specific competitive PHD inhibitor, upregulated HIF-1伪 and VEGF expression and significantly reversed Nox4 knockdown-induced injury. However, Nox2 was scarcely expressed and played a minimal role in CMEC survival and angiogenesis after H/R, though a modest upregulation of Nox2 was observed. In conclusion, this study demonstrated a previously unrecognized protective role of Nox4, a ROS-generating enzyme and the major Nox isoform in CMECs, against H/R injury by inhibiting apoptosis and promoting migration and angiogenesis via a PHD2-dependent upregulation of HIF-1/VEGF proangiogenic signaling.