Myofibroblast-Derived Exosomes Contribute to Development of a Susceptible Substrate for Atrial Fibrillation
Myofibroblast-Derived Exosomes Contribute to Development of a Susceptible Substrate for Atrial Fibrillation
复制标题
肌成纤维细胞衍生的外泌体有助于开发心房颤动的敏感基质
DOI：
10.1159/000505641
复制
发表时间：
2020-05-01
期刊：
影响因子：
1.9
通讯作者：
Yang, Xinchun
中科院分区：
文献类型：
--
作者：
Li, Shichao;Gao, Yuanfeng;Yang, Xinchun
目的：心房纤维化在心房颤动(房颤)中起重要作用。纤维化发病机制中的一个关键事件是成纤维细胞(FBS)活化为肌成纤维细胞(MFBs)。MFBs释放的旁分泌因子导致心肌细胞离子通道表达的改变。L型钙通道Cav1.2表达下调是房颤相关离子重构的标志。然而，Exosome(Exo)介导的MFBs和CMS之间的串扰是否调节Cav1.2的表达仍不清楚。方法：用酶消化法分离和培养新生大鼠的心房FBS和CMS。用血管紧张素II诱导FBS向MFBs的活化，采用共培养和体外处理的方法检测MFB来源的Exos对Cav1.2表达的影响。共聚焦钙成像检测肾上腺素能刺激引起的钙内流信号。采用定量逆转录-聚合酶链式反应(qRT-PCR)检测Cav1.2抑制基因的表达水平。结果：未处理的FBS表达有限数量的α-平滑肌肌动蛋白(α-SMA)，而血管紧张素II诱导表达α-SMA的MFBs显著上调。MFBs与CMS共培养后Cav1.2表达下调，外切体抑制剂GW4869对MFBs的Cav1.2表达有明显的抑制作用。更重要的是，用MFB衍生的Exos处理CMS后，Cav1.2的表达受到抑制。此外，MFB来源的Exos可显著减弱肾上腺素能受体激动剂引起的CMS内钙内流信号，与Cav1.2表达的变化相一致。最后，miR-21-3p，一个潜在的Cav1.2抑制miRNA，在MFB来源的Exos中富含，并在CMS中上调，以响应MFB来源的Exos。结论：我们发现MFBs和CMS之间存在外源性串扰，通过减少CMS中Cav1.2的表达，增加了房颤的易感性。
Objective: Atrial fibrosis plays a critical role in atrial fibrillation (AF). A key event in the pathogenesis of fibrosis is the activation of fibroblasts (FBs) into myofibroblasts (MFBs). Paracrine factors released from MFBs lead to ion channel expression changes in cardiomyocytes (CMs). Downregulation of L-type calcium channel Cav1.2 expression is a hallmark of AF-associated ionic remodeling. However, whether exosome (Exo)-mediated crosstalk between MFBs and CMs regulates Cav1.2 expression remains unknown. Methods: Atrial FBs and CMs were isolated and cultured from neonatal rats by enzymatic digestion. The activation of FBs into MFBs was induced by angiotensin II. Co-culture assay and in vitro Exo treatment were used to determine the effect of MFB-derived Exos on Cav1.2 expression. Confocal Ca2+ imaging was performed to examine the adrenergic stimulation-elicited Ca2+ influx signals. The levels of potential Cav1.2-inhibitory microRNAs (miRNAs) were measured by qRT-PCR. Results: Untreated FBs expressed limited amounts of alpha smooth muscle actin (α-SMA), while angiotensin II induced a significant upregulation of α-SMA-expressing MFBs. Co-cultures of MFBs and CMs resulted in downregulation of Cav1.2 expression in CMs, which was largely abolished by pretreatment of MFBs with exosomal inhibitor GW4869. More importantly, treatment with MFB-derived Exos caused repression of Cav1.2 expression in CMs. Additionally, the adrenergic receptor agonist-elicited Ca2+ influx signals in CMs were remarkably attenuated by pretreatment with MFB-derived Exos, corresponding to the paralleled change in Cav1.2 expression. Finally, miR-21-3p, a potential Cav1.2-inhibitory miRNA, was enriched in MFB-derived Exos and upregulated in CMs in response to MFB-derived Exos. Conclusion: We uncover an Exo-mediated crosstalk between MFBs and CMs, contributing to increased vulnerability to AF by reducing the expression of Cav1.2 in CMs.