Regulated necrosis (necroptosis) and apoptosis are important biological features of ischemia-reperfusion (I/R) injury. However, the molecular mechanisms underlying myocardial necroptosis remain elusive. Leucine rich repeat containing G protein-coupled receptor 6 (LGR6) has been reported to play important roles in various cardiovascular disease. In this study, we aimed to determine whether LGR6 suppresses I/R-induced myocardial necroptosis and the underlying molecular mechanisms. We generated LGR6 knockout mice and used ligation of left anterior descending coronary artery to produce an in vivo I/R model. The effects of LGR6 and its downstream molecules were subsequently identified using RNA sequencing and CHIP assays. We observed significantly downregulated LGR6 expression in hearts post myocardial I/R and cardiomyocytes post hypoxia and reoxygenation (HR). LGR6 deficiency promoted and LGR6 overexpression inhibited necroptosis and acute myocardial injury after I/R. Mechanistically, in vivo and in vitro experiments suggest that LGR6 regulates the expression of STAT2 and ZBP1 by activating the Wnt signaling pathway, thereby inhibiting cardiomyocyte necroptosis after HR. Inhibiting STAT2 and ZBP1 effectively alleviated the aggravating effect of LGR6 deficiency on myocardial necroptosis after I/R. Furthermore, activating LGR6 with RSPO3 also effectively protected mice from acute myocardial I/R injury. Our findings reveal that RSPO3-LGR6 axis downregulates the expression of STAT2 and ZBP1 through the Wnt signaling pathway, thereby inhibiting I/R-induced myocardial injury and necroptosis. Targeting the RSPO3-LGR6 axis may be a potential therapeutic strategy to treat myocardial I/R injury.

中文翻译：

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LGR6 通过抑制坏死性凋亡来防止心肌缺血再灌注损伤


调节坏死（坏死性凋亡）和细胞凋亡是缺血再灌注 （I/R） 损伤的重要生物学特征。然而，心肌坏死性凋亡的分子机制仍然难以捉摸。据报道，含有 G 蛋白偶联受体 6 （LGR6） 的富含亮氨酸的重复序列在各种心血管疾病中起重要作用。在这项研究中，我们旨在确定 LGR6 是否抑制 I/R 诱导的心肌坏死性凋亡及其潜在的分子机制。我们生成了 LGR6 敲除小鼠，并使用左冠状动脉前降支的结扎来产生体内 I/R 模型。随后使用 RNA 测序和 CHIP 测定确定了 LGR6 及其下游分子的作用。我们观察到心肌 I/R 后心脏和缺氧和复氧 （HR） 后心肌细胞中 LGR6 表达显着下调。LGR6 缺陷促进 LGR6 过表达抑制 I/R 后坏死性凋亡和急性心肌损伤。机制上，体内和体外实验表明，LGR6 通过激活 Wnt 信号通路调节 STAT2 和 ZBP1 的表达，从而抑制 HR 后心肌细胞坏死性凋亡。此外，用 RSPO3 激活 LGR6 也有效保护小鼠免受急性心肌 I/R 损伤。我们的研究结果显示，RSPO3-LGR6 轴通过 Wnt 信号通路下调 STAT2 和 ZBP1 的表达，从而抑制 I/R 诱导的心肌损伤和坏死性凋亡。靶向 RSPO3-LGR6 轴可能是治疗心肌 I/R 损伤的潜在治疗策略。