Connexin 43 dephosphorylation mediates the Dchs1/YAP/TEAD signaling pathway to impact cardiac fibrosis

The gap junction protein connexin 43 (Cx43) has been implicated in the development of cardiac fibrosis. We found that Cx43 dephosphorylation at serine 282 (S282) is related to cardiomyocyte apoptosis and arrhythmias in hearts damaged by ischemia/reperfusion. Here, we investigated the effect of Cx43 S282 phosphorylation on fibrosis. We found a decrease in Cx43 S282 phosphorylation in transforming growth factor beta-1 (TGF-β)-induced fibrosis in fibroblasts and an angiotensin II-induced rat model. We transferred a lentivirus with S282A (alanine) into cardiac fibroblasts and an adenovirus with S282A into the hearts of rats. We found that the Cx43 S282A mutation caused fibrosis in cardiac fibroblasts and in the hearts of rats, which suggested that the phosphorylation of Cx43 S282 is important in the development of fibrosis. Furthermore, mRNA sequencing showed that Cx43 dephosphorylation at S282 increased the expression of Dchs1, and Dchs1 inhibited Yes-associated protein (YAP) phosphorylation, subsequently activating the YAP/TEAD signaling pathway and increasing the development of fibrosis. This study suggests that the phosphorylation of Cx43 S282 could be an effective antifibrotic target in cardiac fibroblasts, indicating a novel mechanism and a molecular target that might be promising for the treatment of cardiac fibrosis.间隙连接蛋白 connexin 43（Cx43）已被证实参与心脏纤维化的发生发展过程。本研究发现，Cx43在丝氨酸282（S282）位点的去磷酸化与缺血/再灌注损伤心脏中的心肌细胞凋亡及心律失常密切相关。在此基础上，我们探究了Cx43 S282位点磷酸化对纤维化进程的影响。我们在转化生长因子β1（TGF-β1）诱导的成纤维细胞纤维化模型，以及血管紧张素II诱导的大鼠纤维化模型中，均检测到Cx43 S282位点磷酸化水平的显著降低。随后，我们将携带S282A（丙氨酸）突变的慢病毒转染至心脏成纤维细胞，并将携带该突变的腺病毒注射入大鼠心脏。实验结果显示，Cx43 S282A突变可诱导心脏成纤维细胞及大鼠心脏产生纤维化，这表明Cx43 S282位点的磷酸化在纤维化发展过程中发挥关键调控作用。进一步的mRNA测序分析显示，Cx43在S282位点的去磷酸化可上调Dchs1的基因表达；Dchs1可抑制Yes相关蛋白（YAP）的磷酸化，继而激活YAP/TEAD信号通路，最终促进纤维化的发生发展。本研究表明，Cx43 S282位点的磷酸化可作为心脏成纤维细胞中有效的抗纤维化靶点，为心脏纤维化的治疗提供了全新的机制阐释与潜在分子靶点。