Apolipoprotein A-V: A Functional Proteomics Study

描述（由申请人提供）：我们研究的长期目标是了解血浆甘油三酯（TG）的代谢调节。脂蛋白脂酶和载脂蛋白C-II / C-III等因子可调节血浆TG水平，近年来发现的载脂蛋白A-V（apoA-V）在脂质转运和维持血浆TG稳态中发挥重要作用。为了阐明apoA-V对血浆TG的生理作用的分子基础，将进行体外和体内研究的组合。将进行腺病毒介导的apoa 5（-/-）小鼠基因转移，以在体内评价特定apoA-V变体影响血浆TG水平和脂蛋白代谢的能力。有证据表明apoA-V通过带正电荷的序列基序（残基186-227）结合硫酸乙酰肝素蛋白聚糖、低密度脂蛋白受体家族成员和内皮细胞表面蛋白糖基磷脂酰肌醇高密度脂蛋白结合蛋白1。目的1将测试的假设，该区域的蛋白质是至关重要的表现的TG调制特性的apoA-V在体内。在目的2中，将针对分子内二硫键形成、肝素/受体结合相互作用和体内TG调节能力来表征由c.553G>T SNP引起的与高甘油三酯血症（HTG）相关的apoA-V的变体形式。在目的3中，将测试apoA-V的C-末端结构域对于体内TG调节是必要和充分的假设。此外，在APOA 5转基因小鼠中，将评估NT结构域模拟在携带类似截短形式的apoA-V的人类受试者中观察到的对脂蛋白代谢的影响的能力。目的4在稳定转染的肝癌细胞中研究apoA-V脂滴缔合对TG代谢的影响。所获得的知识将为apoA-V和血浆TG水平之间的关系提供分子解释，并将有助于诊断、治疗和/或预防HTG和相关疾病的策略设计。公共卫生相关性：相关性声明高脂血症是心血管疾病的一个独立危险因素，也是公认的代谢综合征的一个促成因素。对调节血浆甘油三酯水平的因素的了解的增加应该为干预提供新的机会。诊断、预防和/或治疗方面的改进可能会对大量面临心脏病、肥胖和2型糖尿病风险的美国人产生重大影响。

DESCRIPTION (provided by applicant): The long-term goal of our research is to understand the metabolic regulation of plasma triglyceride (TG). Whereas factors such as lipoprotein lipase and apolipoproteins C-II / C-III are known to modulate plasma TG levels, accumulating evidence suggests the recently discovered apolipoprotein A-V (apoA-V) functions in lipid transport and maintenance of plasma TG homeostasis. To elucidate the molecular basis of apoA-V's physiological effects on plasma TG a combination of in vitro and in vivo studies will be performed. Adenovirus mediated gene transfer into apoa5 (-/-) mice will be performed to evaluate in vivo the ability of specific apoA-V variants to influence plasma TG levels and lipoprotein metabolism. Evidence indicates apoA-V binds heparan sulfate proteoglycans, low-density lipoprotein receptor family members and the endothelial cell surface protein glycosylphosphatidylinositol high-density lipoprotein binding protein 1 via a positively charged sequence motif (residues 186-227). Aim 1 will test the hypothesis that this region of the protein is critical for manifestation of the TG modulation properties of apoA-V in vivo. In Aim 2 a variant form of apoA-V correlated with hypertriglcyeridemia (HTG) that results from a c.553G>T SNP will be characterized for intra- molecular disulfide bond formation, heparin / receptor binding interactions and in vivo TG modulation capability. In Aim 3 the hypothesis that the C-terminal domain of apoA-V is necessary and sufficient for TG modulation in vivo will be tested. In addition, in APOA5 transgenic mice, the ability of the NT domain to mimic effects on lipoprotein metabolism seen in human subjects harboring similar truncated forms of apoA-V will be assessed. In Aim 4 the effect of apoA-V lipid droplet association on TG metabolism will be studied in stably transfected hepatoma cells. Knowledge gained will provide a molecular explanation for the relationship between apoA-V and plasma TG levels and will be useful in the design of strategies to diagnose, treat and/or prevent HTG and related disorders. PUBLIC HEALTH RELEVANCE: Statement of Relevance Hypertriglyceridemia is an independent risk factor for cardiovascular disease and is a recognized contributor to development of the metabolic syndrome. Increased understanding of factors that regulate plasma triglyceride levels should provide new opportunities for intervention. Improvements in diagnosis, prevention and/or treatment could have a major impact on the large population of Americans at risk for heart disease, obesity and Type 2 diabetes.