Lysosome Trafficking Dysregulation of Arterial Myocytes in Atherogenesis

动脉粥样硬化中动脉肌细胞的溶酶体运输失调

• 批准号: 9002899
• 负责人: PinLan Li
• 金额: $ 37.63万
• 依托单位: UNIVERSITY OF HOUSTON
• 依托单位国家: 美国
• 财政年份: 2015
• 资助国家: 美国
• 起止时间: 2015-07-15 至 2018-01-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/9002899
• 关键词: 7-ketocholesterol; Acrosome Reaction; Address; Applications Grants; Arteries; Atherosclerosis; Autophagocytosis; Autophagolysosome; Bacteria; Binding; Blood Vessels; Cells; Ceramide Signaling Pathway; Ceramides; Coronary; Coronary artery; Defect; Development; Disease; Dynein ATPase; Endocytosis; Enzymes; Exocytosis; Extracellular Matrix; Failure; Fertilization; Foam Cells; Functional disorder; Health; Heart; Hydrolysis; In Vitro; Inflammation; Injury; Lead; Lipids; Lysosomes; Mammalian Cell; Mediating; Membrane; Microtubules; Molecular; Motor; Movement; Mus; Muscle Cells; Mutation; Myocardial Infarction; Names; Niemann-Pick Diseases; Organelles; Pathogenesis; Pathway interactions; Patients; Phagocytosis; Physiological; Play; Predisposition; Prevention; Production; Proteins; Recycling; Regulation; Reporting; Role; Signal Pathway; Signal Transduction; Smooth Muscle Myocytes; Sphingomyelins; Testing; Time; Vascular Diseases; Vesicle; Work; acid sphingomyelinase; atherogenesis; emerging adult; hypercholesterolemia; in vivo; insight; new therapeutic target; novel therapeutics; oocyte maturation; receptor; receptor recycling; repaired; trafficking; wasting

DESCRIPTION (provided by applicant): Lysosome trafficking has been implicated in a number of cellular activities such as phagocytosis to protect mammalian cells from foreign invaders like bacteria, autophagy to keep these cells surviving or robust, and cellular signaling related to receptor recycling, Ca2+ release and membrane repairing. So far little is known how such lysosome trafficking and associated autophagic flux are regulated in the vasculature. Recent studies have demonstrated that ceramide, a hydrolysis product of sphingomyelin by lysosomal acid sphingomyelinase (ASM), contributes to the control of lysosome functions in coronary arterial smooth muscle cells (CASMCs) and coronary arterial function. Clinically, genetic defects of ASM lead to the lysosomal accumulation of sphingomyelin and a lysosomal storage disorder named Niemann-Pick disease. These Niemann-Pick disease patients are susceptible to the development of atherosclerosis in early adulthood, suggesting that the pathogenesis of atherosclerosis may be associated with the abnormality of ASM-ceramide-mediated regulation of lysosome function. In this grant proposal, our hypothesis is that ASM-ceramide signaling pathway plays a critical tonic regulatory role in lysosome trafficking and autophagic flux in CASMCs and the deficiency of this lysosome regulation may be an important atherogenic mechanism. We will first address whether lysosomal ASM and its product ceramide in CASMCs contribute to the control of lysosome trafficking and associated autophagic flux upon proatherogenic stimulations and to explore the molecular mechanisms by which ASM- ceramide signaling pathway controls lysosome trafficking and fusion (Aim 1). Then, we will determine whether the defect of ASM leads to atherosclerotic injury in coronary arterial wall due to dysregulation of lysosome trafficking and retention of autophagic vesicles using Asm-/- mice and their wild type littermates (Aim 2). Lastly, we will examine how dysregulation of lysosome trafficking and consequent failure of autophagic flux induce atherogenic changes in CASMCs in vitro and in coronary arterial wall in vivo using As--/- mice and their wild type littermates (Aim ). This grant application will for the first time address the molecular mechanisms that actively regulate lysosome trafficking and function via ASM/ceramide pathway in CASMCs and the physiological and pathological relevance to vascular regulation and atherosclerosis. The findings from this proposal will provide new insights into the tonic regulation of lysosome function and the possible pathological relevance to vascular diseases, which may help identify new therapeutic targets for treatment and prevention of atherosclerosis.

描述（由申请人提供）：溶酶体运输涉及许多细胞活性，如保护哺乳动物细胞免受外来入侵者（如细菌）侵袭的吞噬作用、保持这些细胞存活或健壮的自噬作用以及与受体再循环、Ca 2+释放和膜修复相关的细胞信号传导。到目前为止，人们对这种溶酶体运输和相关的自噬通量在脉管系统中是如何调节的知之甚少。近年来的研究表明，神经酰胺作为溶酶体酸性鞘磷脂酶（ASM）水解鞘磷脂的产物，参与了对冠状动脉平滑肌细胞（CASMCs）溶酶体功能的调控和冠状动脉功能的调节。临床上，ASM的遗传缺陷导致鞘磷脂的溶酶体蓄积和称为尼曼-匹克病的溶酶体贮积症。这些尼曼-匹克病患者在成年早期易发生动脉粥样硬化，提示动脉粥样硬化的发病机制可能与ASM-神经酰胺介导的溶酶体功能调节异常有关。在本研究中，我们假设ASM-神经酰胺信号通路在CASMCs的溶酶体运输和自噬流中起关键的紧张性调节作用，这种溶酶体调节的缺陷可能是动脉粥样硬化的重要机制。我们将首先解决CASMC中的溶酶体ASM及其产物神经酰胺是否有助于控制致动脉粥样硬化刺激后的溶酶体运输和相关的自噬通量，并探索ASM-神经酰胺信号通路控制溶酶体运输和融合的分子机制（目的1）。然后，我们将使用Asm-/-小鼠和它们的野生型同窝小鼠确定ASM的缺陷是否由于溶酶体运输和自噬囊泡的保留的失调而导致冠状动脉壁中的动脉粥样硬化损伤（目的2）。最后，我们将研究如何失调的溶酶体运输和随之而来的失败的自噬通量诱导动脉粥样硬化的变化，在体外CASMC和冠状动脉壁在体内使用As-/-小鼠和他们的野生型同窝出生（目的）。该资助申请将首次解决通过ASM/神经酰胺途径在CASMC中积极调节溶酶体运输和功能的分子机制以及与血管调节和动脉粥样硬化的生理和病理相关性。该提案的发现将为溶酶体功能的紧张性调节以及与血管疾病的可能病理相关性提供新的见解，这可能有助于确定治疗和预防动脉粥样硬化的新治疗靶点。