Upregulated ATF6 contributes to chronic intermittent hypoxia-afforded protection against myocardial ischemia/reperfusion injury.
Upregulated ATF6 contributes to chronic intermittent hypoxia-afforded protection against myocardial ischemia/reperfusion injury.
复制标题
上调 ATF6 有助于慢性间歇性缺氧提供针对心肌缺血/再灌注损伤的保护
DOI：
10.3892/ijmm.2016.2535
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发表时间：
2016-05
影响因子：
5.4
通讯作者：
Xiao Y
中科院分区：
文献类型：
--
作者：
Jia W;Jian Z;Li J;Luo L;Zhao L;Zhou Y;Tang F;Xiao Y
在本研究中，我们研究了转录激活因子6（ATF 6）在慢性间歇性缺氧（CIH）增加心肌缺血/再灌注（I/R）耐受性的机制中的作用。使用大鼠体内I/R损伤模型和离体Langendorff灌注的大鼠心脏进行实验。Akt在这一过程中的作用也进行了研究，在体外使用大鼠成肌细胞H9 c2细胞。使用细胞计数试剂盒-8测定法测量细胞活力。乳酸脱氢酶（LDH）和肌酸激酶心肌同工酶活性也被测量为细胞损伤的标志物。通过蛋白质印迹分析来分析ATF 6、Akt和磷酸化（p）-Akt表达。RNA干扰（RNAi）用于抑制ATF 6表达。我们注意到，ATF 6在心室肌的表达显着增加暴露于CIH大鼠。此外，我们注意到CIH在体内I/R后保留了心脏功能，并改善了离体大鼠心脏缺血后心肌功能的恢复。与常氧条件下培养的H9 c2细胞相比，慢性轻度缺氧培养的H9 c2细胞中ATF 6和p-Akt表达上调。慢性轻度缺氧减弱随后的模拟I/R损伤H9 c2细胞（48小时），证明了细胞活力增加和LDH活性下降。相比之下，在siRNA-ATF 6转染的H9 c2细胞中观察到细胞活力降低和LDH活性增加，同时p-Akt水平降低。这些结果表明，ATF 6上调参与CIH减轻心肌I/R损伤的机制，可能通过上调p-Akt，这是心肌细胞存活的关键调节因子。
In the present study, we investigated the role of activating transcription factor 6 (ATF6) in the mechanism by which chronic intermittent hypoxia (CIH) increases tolerance to myocardial ischemia/reperfusion (I/R). Experiments were conducted using a rat model of I/R injury in vivo and isolated Langendorff-perfused rat hearts ex vivo. The role of Akt in this process was also investigated in vitro using rat myoblast H9c2 cells. Cell viability was measured using a cell counting kit-8 assay. Lactate dehydrogenase (LDH) and creatine kinase cardiac isoenzyme activity were also measured as markers of cellular damage. ATF6, Akt and phosphorylated (p)-Akt expression was analyzed by western blot analysis. RNA interference (RNAi) was used to suppress ATF6 expression. We noted that ATF6 expression in the ventricular myocardium was significantly increased in rats exposed to CIH. Furthermore, we noted that CIH preserved cardiac function after I/R in vivo and improved post-ischemic recovery of myocardial performance in isolated rat hearts. ATF6 and p-Akt expression was upregulated in cultured H9c2 cells exposed to chronic mild hypoxia compared with those cultured under normoxic conditions. Chronic mild hypoxia attenuated subsequent simulated I/R injury in H9c2 cells (48 h), as evidenced by increased cell viability and decreased LDH activity. By contrast, decreased cell viability and increased LDH activity were observed in siRNA-ATF6-transfected H9c2 cells, with a concomitant reduction in p-Akt levels. These results indicated that ATF6 upregulation is involved in the mechanism by which CIH attenuates myocardial I/R injury, possibly through upregulation of p-Akt, which is a key regulator of cardiomyocyte survival.