ROLE OF CD36 IN NUTRIENT DELIVERY AND ITS DYSFUNCTION IN AFRICAN AMERICANS

摘要： 清道夫受体CD 36具有脂质和非脂质配体，在代谢和 免疫力CD 36的一个重要功能是其抑制由其配体触发的细胞内信号的能力。 CD 36信号转导有助于调节脂肪酸（FA）利用的几个方面，如脂肪味道 感知，乳糜微粒产生，肠内分泌，FA氧化等。我们最近发现， CD 36与AMPK和胰岛素信号通路相互作用，我们认为这介导了一个重要的 它的一部分行动对养分的利用。我们记录了CD 36与胰岛素分子复合物的存在 受体β（IRβ）和CD 36介导的Fyn和PI 3-激酶的催化p85亚基向IRβ的募集。 我们还发现，棕榈酸与CD 36的结合干扰了Fyn和p85的募集，并使Akt钝化 磷酸化在这个项目中，涉及基础和临床之间的多学科合作， 科学家们，我们将测试新的假设，即膜蛋白CD 36通过其与PI 3 K的相互作用， 途径影响内皮细胞功能，胰岛素对微血管募集的作用， 营养流和高脂肪喂养的影响，导致内皮功能障碍。我们的初步数据文件 CD 36-/-小鼠血管顺应性降低，更重要的是携带编码的非裔美国人 SNP rs3211938使CD 36水平降低50%。我们将研究CD 36的功能意义， 内皮细胞中的信号传导和小鼠内皮细胞CD 36缺失对血管内皮细胞的影响 组织灌注和能量学的功能和胰岛素调节。我们将在这些小鼠中确定 高脂喂养诱导内皮功能障碍，以及是否可通过 磷酸二酯酶5（PDE 5）抑制，其阻断cGMP降解。在一个平行的方法，我们将审查 rs3211938携带者中部分CD 36缺陷对内皮功能障碍影响， 通过胰岛素的微血管募集和PDE 5抑制治疗的功效。肥胖与内皮 功能障碍非常普遍，特别是在非裔美国人中， 和代谢结果。拟议的工作将提供目前无法获得的基本信息 这可能会影响人类内皮功能障碍和胰岛素抵抗的治疗。

ABSTRACT: The scavenger receptor CD36 has lipid and non-lipid ligands and versatile functions in metabolism and immunity. An important function of CD36 is its ability to transduce intracellular signals triggered by its ligands. CD36 signaling contributes to the regulation of several aspects of fatty acid (FA) utilization such as fat taste perception, chylomicron production, enteroendocrine secretion, FA oxidation etc. We recently showed that CD36 interacts with the AMPK and insulin signaling pathways and we propose that this mediates an important part of its actions on nutrient utilization. We document presence of CD36 in a molecular complex with insulin receptor beta (IRβ) and CD36-mediated recruitment to IRβ of Fyn and the catalytic p85 subunit of PI3-kinase. We also find that palmitic acid binding to CD36 interferes with Fyn and p85 recruitment and blunts Akt phosphorylation. In this project, which involves a multidisciplinary collaboration between basic and clinical scientists, we will test the novel hypothesis that the membrane protein CD36 via its interaction with the PI3K pathway influences endothelial cell function, insulin’s action on microvasculature recruitment and consequently nutrient flux and the effect of high fat feeding to cause endothelial dysfunction. Our preliminary data document diminished vascular compliance in CD36-/- mice and more importantly in African Americans carrying coding SNP rs3211938 that reduces CD36 level by 50%. We will examine the functional implications of CD36 signaling in endothelial cells and the consequences of endothelial cell CD36 deletion in mice on vascular function and insulin regulation of tissue perfusion and energetics. We will determine in these mice the effect of high fat feeding to induce endothelial dysfunction and whether this is reversed by treatment with phosphodiesterase 5 (PDE5) inhibition which blocks cGMP degradation. In a parallel approach we will examine influence of partial CD36 deficiency in African American carriers of rs3211938 on endothelial dysfunction, microvascular recruitment by insulin and the efficacy of PDE5 inhibition treatment. Obesity and endothelial dysfunction are highly prevalent especially in African Americans and associate with negative cardiovascular and metabolic outcomes. The proposed work will provide fundamental information that is currently unavailable and that could influence treatment of endothelial dysfunction and insulin resistance in humans.