Regulation of vascular smooth muscle cell function in atherosclerosis

动脉粥样硬化中血管平滑肌细胞功能的调节

• 批准号: 9401283
• 负责人: Yabing Chen
• 金额: $ 53.3万
• 依托单位: UNIVERSITY OF ALABAMA AT BIRMINGHAM
• 依托单位国家: 美国
• 财政年份: 2017
• 资助国家: 美国
• 起止时间: 2017-07-01 至 2021-05-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/9401283
• 关键词: Actins; Animals; Apolipoprotein E; Arterial Fatty Streak; Atherosclerosis; Blood Vessels; Calcified; Calcium; Calcium Signaling; Cardiac; Cardiovascular system; Cell physiology; Cells; Characteristics; Clinical; Cytoskeleton; Development; Disease; Echocardiography; Elasticity; Embryo; Event; Exocytosis; Extracellular Matrix; Health; Homologous Gene; Human; Immune System Diseases; In Vitro; Lead; Link; Mediating; Mediator of activation protein; Membrane; Modeling; Molecular; Morbidity - disease rate; Mus; Muscle Cells; Mutation; Osteogenesis; Outcome; PLC gamma1; PLCgamma2; Pathogenesis; Patients; Phenotype; Phospholipids; Play; Process; Protein Isoforms; Proteins; Receptor Protein-Tyrosine Kinases; Regulation; Resolution; Role; Signal Pathway; Signal Transduction; Structure; Supporting Cell; Synaptic Vesicles; Tissues; United States; Vascular Smooth Muscle; Vascular System; Vascular calcification; Vesicle; bone cell; calcification; design; effective therapy; in vivo; insight; mineralization; mortality; mouse model; nanoparticle; novel; osteogenic; phospholipase C gamma

ABSTRACT Regulation of vascular smooth muscle cells (VSMC) phenotype and function plays important roles in the pathogenesis of atherosclerosis. Vascular calcification is a characteristic feature of atherosclerosis that predicts adverse cardiovascular outcome of atherosclerotic patients. Over the last two decades, increasing studies have demonstrated that vascular calcification is a regulated process; and osteogenic differentiation and calcification of VSMC contributes significantly to the development of vascular calcification. Calcium signaling is critical in regulating VSMC function. However, the role of the key intracellular calcium signaling mediator, phospholipase Cγ (PLCγ), in regulating VSMC calcification is entirely unknown. Our preliminary studies demonstrated that deletion of PLCγ2 markedly increased calcification in VSMC and in atherosclerotic lesions of ApoE-/- mice. Using VSMC from PLCγ2 deletion mice (PLCγ2-/-), we determined a direct effect of PLCγ2 deficiency on promoting VSMC calcification, which was independent of the PLCγ1 isoform or the known PLCγ- mediated signaling pathways, supporting a unique and novel function of PLCγ2 in regulating VSMC calcification. PLCγ2 deletion in VSMC altered cytoskeleton structure and increased secretion of matrix vesicles (MVs), membrane-bound nanoparticles that harbor calcium and matrix proteins. MV secretion is a key cellular event in osteogenesis that initiates extracellular matrix calcification during bone formation; and has recently been shown to play an important role in vascular calcification. However, the molecular regulations of MV secretion in VSMC are poorly understood. We found that restoring PLCγ2 normalized MV secretion and inhibited calcification of the PLCγ2-/- VSMC. Furthermore, PLCγ2 interacted with membrane-associated filamentous proteins, septin 4/5, which have been shown to dynamically interact with membrane phospholipids and exocytosis machinery proteins that regulate cytoskeleton arrangement and synaptic vesicle secretion. The roles of septins in VSMC MV secretion are unknown, our findings of PLCγ2/septin4/5 interactions and increased septin 4/5 in MVs from PLCγ2-/- VSMC support a new role of septins in regulating VSMC MV secretion and calcification. Therefore, we hypothesize that PLCγ2 deficiency induces VSMC calcification via altered septin/actin-cytoskeleton structure that leads to increased MV secretion. With our new mouse models, Aim 1 will determine the function of SMC-specific PLCγ2 in regulating vascular function in vivo; and Aim 2 will elucidate the molecular mechanisms underlying PLCγ2-regulated VSMC calcification. These studies will elucidate an integrative role of SMC-derived PLCγ2 in regulating cytoskeleton structure and MV secretion that lead to VSMC calcification. PLCγ2 mutations in humans have recently been identified to cause immunological diseases but the underlying mechanisms are not fully understood. Therefore, delineating the novel function and mechanisms whereby PLCγ2-regulated vascular function should provide novel insights into the comprehensive function of PLCγ2 in health and disease beyond the vascular system.

摘要 血管平滑肌细胞 (VSMC) 表型和功能的调节非常重要 血管钙化是动脉粥样硬化的一个典型特征。 预测动脉粥样硬化患者的不良心血管结果在过去二十年中不断增加。 研究表明，血管钙化是一个受调节的过程；成骨分化和 VSMC 钙化对血管钙化信号的发展有显着贡献。 然而，细胞内钙信号传导介质的作用至关重要。 磷脂酶 Cγ (PLCγ) 在调节 VSMC 钙化方面的作用我们的初步研究完全未知。 PLCγ2 的缺失显着增加了 VSMC 和动脉粥样硬化病变中的钙化 使用 PLCγ2 缺失小鼠 (PLCγ2-/-) 的 VSMC，我们确定了 PLCγ2 的直接作用。 促进 VSMC 钙化的缺陷，这与 PLCγ1 亚型或已知的 PLCγ- 无关 介导的信号通路，支持 PLCγ2 在调节 VSMC 中独特而新颖的功能 VSMC 中的 PLCγ2 缺失改变了细胞骨架结构并增加了基质囊泡的分泌。 （MV），含有钙和基质蛋白的膜结合纳米粒子是关键的细胞分泌。 成骨过程中的事件，在骨形成过程中启动细胞外基质钙化； 已被证明在血管钙化中发挥重要作用，然而，MV 的分子调控。 我们对 VSMC 中的分泌知之甚少，我们发现恢复 PLCγ2 可使 MV 分泌和正常化。 抑制 PLCγ2-/- VSMC 的钙化 此外，PLCγ2 与膜相关的相互作用。 丝状蛋白 septin 4/5，已被证明与膜磷脂动态相互作用 和调节细胞骨架排列和突触小泡分泌的胞吐机制蛋白。 septins 在 VSMC MV 分泌中的作用尚不清楚，我们对 PLCγ2/septin4/5 相互作用的发现和 PLCγ2-/- VSMC 中 MV 中的 septin 4/5 增加支持 septin 在调节 VSMC MV 中的新作用 因此，我们推测PLCγ2缺陷会诱导VSMC钙化。 通过改变隔膜/肌动蛋白细胞骨架结构，导致MV分泌增加。 小鼠模型，目标1将确定SMC特异性PLCγ2在调节体内血管功能中的功能； 目标 2 将阐明 PLCγ2 调节的 VSMC 钙化的分子机制。 研究将阐明 SMC 衍生的 PLCγ2 在调节细胞骨架结构和 MV 中的综合作用 最近已发现导致人类 VSMC 钙化的分泌物 PLCγ2 突变。 免疫性疾病，但其潜在机制尚不完全清楚。 PLCγ2调节血管功能的新功能和机制应该为以下方面提供新的见解 PLCγ2 在血管系统以外的健康和疾病中的综合功能。