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。虽然已知脂蛋白脂肪酶和载脂蛋白C-II / C-III等因素可调节血浆TG水平，但越来越多的证据表明，最近发现的载脂蛋白A-V （apoA-V）在脂质转运和维持血浆TG稳态中起作用。为了阐明apoA-V对血浆TG生理影响的分子基础，我们将进行体内外联合研究。将进行腺病毒介导的基因转移到apoa5（-/-）小鼠体内，以评估特定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通过带正电的序列基序结合硫酸肝素蛋白聚糖、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（残基186-227）。目的1将验证该蛋白质区域对apoA-V体内TG调节特性的表现至关重要的假设。在Aim 2中，一种与高甘油三酯血症（HTG）相关的apoA-V变异形式，由c.553G>T SNP引起，将被表征为分子内二硫键形成、肝素/受体结合相互作用和体内TG调节能力。在Aim 3中，将测试apoA-V的c端结构域是体内TG调节的必要和充分的假设。此外，在APOA5转基因小鼠中，NT结构域模拟apoA-V类似截断形式的人类受试者的脂蛋白代谢影响的能力将被评估。在Aim 4中，我们将在稳定转染的肝癌细胞中研究apoA-V脂滴关联对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，并将有助于设计诊断、治疗和/或预防HTG及相关疾病的策略。公共卫生相关性：相关性声明高甘油三酯血症是心血管疾病的独立危险因素，是代谢综合征发展的公认因素。对调节血浆甘油三酯水平的因素的进一步了解将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.