Musclin通过调控线粒体分裂/融合参与糖尿病血管平滑肌细胞增殖的研究

Proliferation of Diabetes Vascular Smooth Muscle Cell (VSMC)is the core mechanism for the development of atherosclerosis. High-glucose has been shown to induce VSMC proliferation and fission/fussion imbalance. We have previously demonstrated that musclin was significantly elevated in VSMC from diabetic rats,which led to an increase in intracellular calcium. Our preliminary data shows that high glucose stimulation enhance musclin expression, and exogenous musclin induce mitochondrial fission/fussion imbalance in VSMC. Therefore,it is tempting to speculate that musclin facilitate the proliferation of VSMC in diabetes by regulating calcium signaling and mitochondrial fission/fussion. In order to investigate the mechanism of musclin in VSMC proliferation in diabete ,we will use gene editing tools to study the role of musclin in mitochondrial fission/fussion and the proliferation of vascular smooth muscle in rat model and cell model. This study may shed light in to the pathogenesis of diabetes and atherosclerosis, and identify novel therapeutic targets.

血管平滑肌细胞(vascular smooth muscle cell,VSMC)增殖是糖尿病并发动脉粥样硬化的显著特征。近年研究证实高糖能引起线粒体分裂融合异常和VSMC增殖，但机制尚待研究。我们前期研究证实内源性活性肽Musclin在糖尿病大鼠VSMC中表达增加，且Musclin增加细胞内钙。预实验发现：高糖孵育VSMC使Musclin表达增加，外源性给予Musclin能够导致细胞线粒体分裂融合异常。因而我们推测“Musclin能够通过调控钙信号-线粒体分裂/融合促进糖尿病VSMC增殖”。为证实这一假说，本项目拟在动物和细胞水平构建糖尿病模型，观察Musclin在VSMC增殖中的表达规律和作用，采用工具药物和基因编辑技术干预钙信号-线粒体分裂融合通路探讨其在Musclin影响VSMC增殖中的调控机制，揭示糖尿病VSMC增殖的分子机制，为糖尿病及其并发的动脉粥样硬化防治提供科学依据。

血管平滑肌细胞(vascular smooth muscle cell,VSMC)增殖是糖尿病并发动脉粥样硬化的显著特征，如何逆转是医学难题。近年研究证实高糖能引起线粒体分裂融合异常和VSMC增殖，但机制尚待研究。肌肉素（Musclin）是一种内分泌活性多肽，参与胰岛素抵抗等多种病理生理过程。本课题组以糖尿病大鼠和原代培养的VSMC为研究对象，以形态学、病理学、分子生物学等为手段，给予外源性Musclin活性肽和Musclin-siRNA敲低干预后，观察对糖尿病大鼠血管组织、原代培养的VSMC的增殖情况以及细胞钙通道和线粒体分裂融合的影响，分析Musclin的变化与糖尿病血管增殖的内在关系。研究结果提示糖尿病大鼠以及高糖诱导的VSMC中Musclin表达水平显著升高，并伴有VSMC的增殖和线粒体分裂融合失衡以及细胞内钙增加。给予Musclin敲低干预后，VSMC线粒体分裂融合失衡以及增殖情况显著改善。为深入探讨相关机制，给予VSMC钙离子螯合剂后发现能够显著改善Musclin诱导的线粒体分裂融合失衡和细胞增殖。同样给予VSMC线粒体分裂融合抑制剂Mdivi-1能够逆转Musclin诱导的细胞增殖。这一研究结果提示Musclin可通过促进细胞内钙增加诱导VSMC线粒体分裂融合失调，参与糖尿病导致的VSMC增殖，而抑制Musclin表达可减轻上述环节。故糖尿病可能通过Musclin介导的细胞内钙增加引起线粒体分裂融合失衡增从而导致血管重塑，抑制Musclin可能成为防治糖尿病血管病变的新靶点。