Department of Cardiothoracic Surgery, The Second Hospital of Anhui Medical University, Hefei, 230601, China.
Department of Pharmacology, School of Basic Medical Sciences, Anhui Medical University, Hefei, 230032, China.
Inflammation. 2020 Jun;43(3):1065-1076. doi: 10.1007/s10753-020-01191-3.
Cell death and inflammation play critical roles in cardiac fibrosis. During the fibrosis process, inflammation and tissue injury were triggered; however, the mechanisms initiating cardiac fibrosis and driving fibroblast pyroptosis remained largely unknown. In this study, we identified long non-coding RNA (LncRNA)-GAS5 as the key onset of cardiac fibroblast pyroptosis and cardiac fibrosis. Here, we detected ISO-induced cardiac fibrosis models and cardiac fibroblast pyroptosis model by stimulating with LPS. We found that the expression of pyroptosis-related proteins such as caspase 1, NLRP3, and DNMT1 was increased in cardiac fibrosis tissue, while the expression of GAS5 was decreased. The overexpressing of LncRNA GAS5 was shown to increase and inhibit cardiac fibroblast pyroptosis, as well as attenuate caspase 1 and NLRP3 expression in cardiac fibroblast. However, the silencing of GAS5 was also observed; it shows the opposite situation. Furthermore, further studies revealed that treatment of DNMT inhibitor, 5-aza-2-deoxycytidine, or downregulation of DNMT1 led to increased GAS5 expression by reversion of promoter hypermethylation in cardiac fibroblast. Importantly, we have demonstrated that DNMT1 methylation of LncRNA GAS5 leads to cardiac fibroblast pyroptosis via affecting NLRP3 axis. Our findings indicate a new regulatory mechanism for cardiac fibroblast pyroptosis under LPS stress, providing a novel therapeutic target for cardiac fibrosis. Graphical Abstract.
细胞死亡和炎症在心脏纤维化中起着关键作用。在纤维化过程中，炎症和组织损伤被触发；然而，引发心脏纤维化和驱动成纤维细胞焦亡的机制在很大程度上仍不清楚。在这项研究中，我们确定长非编码 RNA (LncRNA)-GAS5 是心脏成纤维细胞焦亡和心脏纤维化的关键起始因子。在这里，我们通过用 LPS 刺激检测了 ISO 诱导的心脏纤维化模型和心脏成纤维细胞焦亡模型。我们发现，心脏纤维化组织中促炎细胞因子相关蛋白如半胱氨酸天冬氨酸蛋白酶 1 (caspase 1)、NLRP3 和 DNA 甲基转移酶 1 (DNMT1)的表达增加，而 GAS5 的表达减少。上调 LncRNA GAS5 可增加并抑制心脏成纤维细胞焦亡，并降低心脏成纤维细胞中 caspase 1 和 NLRP3 的表达。然而，沉默 GAS5 也观察到了相反的情况。此外，进一步的研究表明，用 DNA 甲基转移酶抑制剂 5-氮杂-2′-脱氧胞苷处理或下调 DNMT1 可通过逆转心脏成纤维细胞启动子超甲基化导致 GAS5 表达增加。重要的是，我们已经证明，DNMT1 对 LncRNA GAS5 的甲基化通过影响 NLRP3 轴导致心脏成纤维细胞焦亡。我们的研究结果表明，LPS 应激下心脏成纤维细胞焦亡存在新的调控机制，为心脏纤维化提供了新的治疗靶点。
