Sun Weiming, Yang Jinxia, Zhang Yuanzhou, Xi Yuxin, Wen Xin, Yuan Di, Wang Yuehong, Wei Can, Wang Rui, Wu Lingyun, Li Hongzhu, Xu Changqing
Department of Pathophysiology, Harbin Medical University, Baojian Road, Harbin, 150081 China.
The Key Laboratory of Cardiovascular Medicine Research (Harbin Medical University), Ministry of Education, Harbin, China.
Cell Biosci. 2017 Dec 11;7:67. doi: 10.1186/s13578-017-0196-9. eCollection 2017.
A gasotransmitter hydrogen sulfide (HS) plays an important physiological and pathological role in cardiovascular system. Ischemic post-conditioning (PC) provides cardioprotection in the young hearts but not in the aged hearts. Exogenous HS restores PC-induced cardioprotection by inhibition of mitochondrial permeability transition pore opening and oxidative stress and increase of autophagy in the aged hearts. However, whether HS contributes to the recovery of PC-induced cardioprotection via down-regulation of endoplasmic reticulum stress (ERS) in the aged hearts is unclear.
The aged H9C2 cells (the cardiomyocytes line) were induced using HO and were exposed to H/R and PC protocols. Cell viability was observed by CCK-8 kit. Apoptosis was detected by Hoechst 33342 staining and flow cytometry. Related protein expressions were detected through Western blot.
In the present study, we found that 30 μM HO induced H9C2 cells senescence but not apoptosis. Supplementation of NaHS protected against H/R-induced apoptosis, the expression of cleaved caspase-3 and cleaved caspase-9 and the release of cytochrome . The addition of NaHS also counteracted the reduction of cell viability caused by H/R and decreased the expression of GRP 78, CHOP, cleaved caspase-12, ATF 4, ATF 6 and XBP-1 and the phosphorylation of PERK, eIF 2α and IRE 1α. Additionally, NaHS increased Bcl-2 expression. PC alone did not provide cardioprotection in H/R-treated aged cardiomyocytes, which was significantly restored by the supplementation of NaHS. The beneficial role of NaHS was similar to the supply of 4-PBA (an inhibitor of ERS), GSK2656157 (an inhibitor of PERK), STF083010 (an inhibitor of IRE 1α), respectively, during PC.
Our results suggest that the recovery of myocardial protection from PC by exogenous HS is associated with the inhibition of ERS via down-regulating PERK-eIF 2α-ATF 4, IRE 1α-XBP-1 and ATF 6 pathways in the aged cardiomyocytes.
气体信号分子硫化氢（HS）在心血管系统中发挥着重要的生理和病理作用。缺血后处理（PC）对年轻心脏具有心脏保护作用，但对老年心脏则不然。外源性HS通过抑制线粒体通透性转换孔开放和氧化应激以及增加老年心脏中的自噬来恢复PC诱导的心脏保护作用。然而，HS是否通过下调老年心脏中的内质网应激（ERS）来促进PC诱导的心脏保护作用的恢复尚不清楚。
使用HO诱导老年H9C2细胞（心肌细胞系），并使其暴露于H/R和PC方案。通过CCK-8试剂盒观察细胞活力。通过Hoechst 33342染色和流式细胞术检测细胞凋亡。通过蛋白质印迹法检测相关蛋白表达。
在本研究中，我们发现30μM HO诱导H9C2细胞衰老但不诱导凋亡。补充NaHS可防止H/R诱导的凋亡、裂解的caspase-3和裂解的caspase-9的表达以及细胞色素的释放。添加NaHS还可抵消H/R引起的细胞活力降低，并降低GRP 78、CHOP、裂解的caspase-12、ATF 4、ATF 6和XBP-1的表达以及PERK、eIF 2α和IRE 1α的磷酸化。此外，NaHS增加Bcl-2表达。单独的PC对H/R处理的老年心肌细胞没有提供心脏保护作用，补充NaHS可显著恢复这种作用。NaHS的有益作用分别类似于在PC期间提供4-PBA（一种ERS抑制剂）、GSK2656157（一种PERK抑制剂）、STF083010（一种IRE 1α抑制剂）。
我们的结果表明，外源性HS使PC对心肌的保护作用恢复与通过下调老年心肌细胞中PERK-eIF 2α-ATF 4、IRE 1α-XBP-1和ATF 6途径抑制ERS有关。
