Pannexin-1-FAM134B依赖性内质网自噬途径介导Apelin-13/APJ促心肌肥厚

Supporting by previous National Natural Science Project, the applicant confirmed that Apelin-13 which was the endogenous ligand for APJ receptor promoted myocardial hypertrophy. APJ receptor also mediated the process of stress-induced myocardial hypertrophy. However, the mechanism of Apelin-13/APJ induced myocardial hypertrophy is still obscure. Further preliminary experiment results showed that apelin-13 promoted the expression of Pannexin-1 and FAM134B. Apelin-13 also enhanced the level of reticulophagy. Applicant put forward a hypothesis that Pannexin-1 hemichannel-FAM134B mediated-reticulophagy pathway involves in the myocardial hypertrophy induced by Apelin-13/APJ. Applicant will adopt transmission electron microscope, immunoflurescence, autophagy flux, RNAi and hypertrophy animal model to clarify whether Pannexin-1 hemichannel-FAM134B mediated-reticulophagy pathway involves in apelin-13/APJ-induced myocardial hypertrophy or not. This project will reveal the detail mechanism for apelin-13/APJ promoting myocardial hypertrophy by Pannexin-1 hemichannel and FAM134B mediated-reticulophagy pathway. This project also provide the experiment evidences for APJ receptor becoming the new treatment target for myocardial hypertrophy.

申请者国自青年项目研究发现APJ受体及内源性配体Apelin-13具有促心肌肥厚的作用，但机制仍未阐明。预实验发现Apelin-13促进新型通道蛋白Pannexin-1表达，增加内质网自噬受体FAM134B的表达，诱导内质网自噬。据此提出“Pannexin-1半通道-FAM134B依赖性内质网自噬途径介导Apelin-13/APJ促心肌肥厚”的科学假说。课题拟采用透射电镜、激光共聚焦成像、RNA干扰及心肌肥厚动物模型等方法深入探讨Apelin-13/APJ促进Pannexin-1半通道的激活，明确Pannexin-1半通道调控FAM134B依赖性内质网自噬，阐明Pannexin-1半通道-FAM134B依赖性内质网自噬途径介导Apelin-13/APJ促心肌肥厚的机制。课题将揭示Apelin-13/APJ促心肌肥厚的分子调控新途径，并为APJ受体成为心肌肥厚治疗新靶点提供实验依据。

本研究探讨了Apelin-13/APJ显著促进心肌细胞中Pannexin-1半通道的表达，并激活Pannexin-1半通道开放，诱导FAM34B依赖性内质网自噬的发生，进而促进心肌细胞肥大，阐明Pannexin-1半通道-FAM134B依赖性内质网自噬途径介导Apelin-13/APJ促心肌细胞肥大的机制。研究发现：1. Apelin-13促进心肌细胞中的Pannexin-1的表达，并激活Pannexin-1通道开放。APJ拮抗剂F13A、Pannexin-1半通道抑制剂 Carbrnoxolone (CBX)和Probenecid（PBC）均显著抑制Apelin-13诱导的Pannexin-1表达和激活。2. Apelin-13促进心肌细胞中P2X7受体的表达，F13A、CBX和PBC显著抑制Apelin-13诱导的P2X7的表达。3. Apelin-13促进FAM34B依赖性内质网自噬，F13A、CBX、PBC、A-804598和siRNA-P2X7显著抑制Apelin-13诱导的FAM34B依赖性内质网自噬。4. Apelin-13促进心肌细胞肥大，F13A、CBX、PBC、A-804598、siRNA-P2X7、siRNA-FAM134B显著抑制Apelin-13诱导的心肌细胞肥大。5. 检测人体心肌肥厚及非心肌肥厚组的尸检标本，发现与非心肌肥厚组比较，心肌肥厚组BNP、Apelin、APJ、Pannexin-1、FAM134B和Beclin-1的表达增加。本研究从G蛋白偶联受体APJ及其内源性配体Apelin-13 这一新的切入点，探讨了Pannexin-1 半通道调控FAM134B依赖性内质网自噬的重要作用，明确Pannexin-1半通道-FAM134B依赖性内质网自噬途径介导Apelin-13/APJ 促心肌肥厚的分子机制，为Apelin-13/APJ 促心肌肥厚的形成机理提供新的理论依据，进一步为以APJ 受体作为药物分子靶标，在筛选防治心肌肥厚的新药中具有重要的意义。