Wu Cheng-Zhe, Li Xiang, Hong Lan, Han Zhuo-Na, Liu Ying, Wei Cheng-Xi, Cui Xun
Department of Physiology, School of Medicine, Yanbian University, Yanji 133-002, China.
Institute of Clinical Medicine, Yanbian University, Yanji 133-002, China.
Korean J Physiol Pharmacol. 2021 Mar 1;25(2):159-166. doi: 10.4196/kjpp.2021.25.2.159.
Nicotinamide adenine dinucleotide phosphate oxidases (NOXs) are the major enzymatic source of reactive oxygen species (ROS). NOX2 and NOX4 are expressed in the heart but its role in hypoxia-induced atrial natriuretic peptide (ANP) secretion is unclear. This study investigated the effect of NOX on ANP secretion induced by hypoxia in isolated beating rat atria. The results showed that hypoxia significantly upregulated NOX4 but not NOX2 expression, which was completely abolished by endothelin-1 (ET-1) type A and B receptor antagonists BQ123 (0.3 µM) and BQ788 (0.3 µM). ET-1-upregulated NOX4 expression was also blocked by antagonists of secreted phospholipase A2 (sPLA2; varespladib, 5.0 µM) and cytosolic PLA2 (cPLA2; CAY10650, 120.0 nM), and ET-1-induced cPLA2 expression was inhibited by varespladib under normoxia. Moreover, hypoxia-increased ANP secretion was evidently attenuated by the NOX4 antagonist GLX351322 (35.0 µM) and inhibitor of ROS N-Acetyl-D-cysteine (NAC, 15.0 mM), and hypoxia-increased production of ROS was blocked by GLX351322. In addition, hypoxia markedly upregulated Src expression, which was blocked by ET receptors, NOX4, and ROS antagonists. ET-1-increased Src expression was also inhibited by NAC under normoxia. Furthermore, hypoxiaactivated extracellular signal-regulated kinase 1/2 (ERK1/2) and protein kinase B (Akt) were completely abolished by Src inhibitor 1 (1.0 µM), and hypoxia-increased GATA4 was inhibited by the ERK1/2 and Akt antagonists PD98059 (10.0 µM) and LY294002 (10.0 µM), respectively. However, hypoxia-induced ANP secretion was substantially inhibited by Src inhibitor. These results indicate that NOX4/Src modulated by ET-1 regulates ANP secretion by activating ERK1/2 and Akt/GATA4 signaling in isolated beating rat hypoxic atria.
烟酰胺腺嘌呤二核苷酸磷酸氧化酶（NOXs）是活性氧（ROS）的主要酶源。NOX2和NOX4在心脏中表达，但其在缺氧诱导的心房利钠肽（ANP）分泌中的作用尚不清楚。本研究调查了NOX对离体搏动大鼠心房缺氧诱导的ANP分泌的影响。结果显示，缺氧显著上调NOX4的表达，但不影响NOX2的表达，内皮素-1（ET-1）A 型和 B 型受体拮抗剂BQ123（0.3 μM）和BQ788（0.3 μM）可完全消除这种上调。分泌型磷脂酶A2（sPLA2；伐地考昔，5.0 μM）和胞质型磷脂酶A2（cPLA2；CAY10650，120.0 nM）的拮抗剂也可阻断ET-1上调的NOX4表达，并且在常氧条件下，伐地考昔可抑制ET-1诱导的cPLA2表达。此外，NOX4拮抗剂GLX351322（35.0 μM）和ROS抑制剂N-乙酰-D-半胱氨酸（NAC，15.0 mM）可明显减弱缺氧诱导的ANP分泌增加，并且GLX351322可阻断缺氧诱导的ROS产生增加。另外，缺氧显著上调Src的表达，ET受体、NOX4和ROS拮抗剂可阻断这种上调。在常氧条件下，NAC也可抑制ET-1增加的Src表达。此外，Src抑制剂1（1.0 μM）可完全消除缺氧激活的细胞外信号调节激酶1/2（ERK1/2）和蛋白激酶B（Akt），ERK1/2拮抗剂PD98059（10.0 μM）和Akt拮抗剂LY294002（10.0 μM）分别可抑制缺氧增加的GATA4。然而，Src抑制剂可显著抑制缺氧诱导的ANP分泌。这些结果表明，ET-1调节的NOX4/Src通过激活离体搏动大鼠缺氧心房中的ERK1/2和Akt/GATA4信号通路来调节ANP分泌。
