心脏瓣膜病及其并发房颤是我国的常见病，其房颤的发病机制尚不明确。我们的前期研究发现PPAR信号通路及钙激活性钾离子通道（KCa离子通道）的表达两者在心脏瓣膜病并发房颤中均异常。有研究表明PPARγ信号通路以及KCa离子通道均与房颤发生有关，但PPARγ信号通路是否调控KCa离子通道的活动引发房颤尚属未知。 本项目将在我们前期研究的基础上应用转录组学及蛋白质组学分析心脏瓣膜病并发房颤患者的差异信号通路，分析PPAR信号通路中出现异常转录或翻译的RNA或蛋白质，通过膜片钳技术测定患者心房肌细胞中KCa的电活动，进一步应用RNA干扰技术，在细胞模型及PPARγ基因敲除鼠中获取PPARγ信号通路异常影响KCa功能的直接证据，以验证PPARγ信号通路异常活动调控KCa离子通道是房颤发生重要机制的科学假说。 本项目将为深入理解心脏瓣膜病并发房颤的机制并为最终实现其早期干预治疗打下基础。

Heart valve disease and associated atrial fibrillation (AF) are common heart diseases in China. However, the mechanism of AF in heart valve disease is unclear. There is evidence that both PPAR signal pathway related to lipid metabolism and KCa channels are involved in the AF associated with heart valve disease. Our preliminary studies have demonstrated that the PPAR signal pathway and KCa channels are abnormal in heart valve disease associated with AF but whether the PPAR signal pathway regulates KCa channels that results in AF is unknown. The present project will test the scientific hypothesis that the PPAR signal pathway regulates KCa channels that is an important mechanism in the development of AF in heart valve disease. To test this hypothesis, we will analyze differentially expressed RNA or proteins in PPAR signal pathway by using transcriptomic and proteomic technologies. We will also use patch-clamp techniqueto measure the electrical activity of KCa in the atrial myocytes from the patients undergoing heart valve surgery. In addition, we will further investigate to obtain the direct evidence of PPAR signal pathway regulating KCa channels by using RNA interference technique and etc., in cell model and knock-out mouse model, in order to demonstrate that the PPAR signal pathway regulates KCa channels and this is an important mechanism in the development of AF in the heart valve disease. The present project will therefore make a scientific basis for better understanding the mechanism of the AF associated with heart valve disease and for the early management of this disease as the final goal.

房颤是常见病。正常人群中房颤的发病率约为1-2%。心脏瓣膜病及并发房颤是我国的常见病。电重构和结构重构是房颤细胞电生理的主要表现形式，但房颤的发病机制尚不明确。 我们的前期研究发现PPAR信号通路及钙激活性钾离子通道（KCa离子通道）相关蛋白的表达在心脏瓣膜病并发房颤中均有异常。 本项目在前期研究的基础上，继续收集心脏瓣膜病房颤和窦性心律患者的心房组织62例，血浆100例。通过转录组学和蛋白组学的研究，比较房颤患者左、右房组织，窦性心律患者右房组织中出现差异变化的信号通路，发现了预期中KCa离子通道相关基因或蛋白的显著性改变，与已发表的文献相比结果类似。更重要的是，我们首次发现氯离子通道蛋白CLIC1，CLIC4，CLIC5在房颤患者组织中显著上调，显示氯离子通道与房颤的发生有一定相关性；结合血浆的蛋白组学和代谢组学结果，综合分析发现，PPAR通路中多个蛋白发生显著性改变，进一步证实PPAR通路参与了房颤的发生过程；同时我们利用荧光定量PCR、蛋白免疫印迹，免疫组化、电镜、酶联免疫等方法对组学结果进行了验证。 综上所述，我们在转录组、蛋白组和代谢组多组学水平，对心脏瓣膜病房颤和窦性心律患者心房组织和血浆进行综合研究，结果表明氯离子通道和PPAR信号通路与房颤的发生密切相关，同时实验中发现的发生显著性差异的蛋白和代谢物，如ApoA-I, ApoA-II, LMO7等，可能进一步发展为心脏瓣膜病相关房颤诊断的生物标志物。这一项目为下一步确定PPAR通路等在房颤中的作用打下了良好的基础。