LONG-CHAIN ACYL-COA SYNTHETASES IN VASCULAR CELLS

描述(由申请人提供)：甘油三酯会增加糖尿病患者的心血管死亡率。在动脉粥样硬化的病变中，长链脂肪酸从甘油三酯中释放出来，并被酯化为CoA，以便通过长链acyI-CoA合成酶(ACS1-5)催化的反应被血管细胞利用。油酸是甘油三酯中最常见的脂肪酸，在血管细胞中具有重要的促动脉粥样硬化作用。将回答四个问题：1.在原代培养的平滑肌细胞(SMCs)和巨噬细胞中表达哪些ACS亚型，它们是否受葡萄糖和脂类的调节？我们假设原代SMC和巨噬细胞表达几种不同的ACS亚型，并且它们在体外和体内的表达受葡萄糖和脂类的不同调控。对于体内研究，我们开发了一种新的糖尿病加速动脉粥样硬化的转基因小鼠模型。2.在生长因子刺激下，在SMC中，ACS2是否是OA掺入磷脂酰胆碱和产生富含OA的1，2-二酰甘油所必需的？在生长因子刺激下，磷脂酶D通过产生1，2-二酰甘油(1，2-DAG)来增强生长因子对SMC的促有丝分裂作用。我们推测ACS2介导了在生长因子刺激下，在磷脂酰胆碱中的OA掺入和1，2-DAG的产生。我们建议通过使用ACS抑制剂和RNAi来抑制ACS2。3.ACS2是否是OA促进生长因子诱导的SMC增殖所必需的？我们假设ACS2是OA促进生长因子诱导的SMC增殖所必需的。ACS异构体的抑制剂和RNAi将被用来抑制OA介导的生长因子有丝分裂效应的增强。4.在OA诱导的巨噬细胞死亡和抑制胆固醇外流过程中，需要哪种特异性的ACs亚型(S)？OA诱导巨噬细胞死亡，抑制胆固醇外流。我们假设特定的ACS亚型是这些事件所必需的。ACS抑制剂和RNAi将被用来确定介导OA诱导的巨噬细胞死亡、胆固醇外流和脂代谢的ACS亚型。到目前为止，血管细胞中的ACS亚型还没有被研究过。我们期望在初级的平滑肌和巨噬细胞中鉴定出OA的重要生物学效应所需的ACS亚型。

DESCRIPTION (provided by applicant): Triglycerides contribute to the increased cardiovascular mortality in people with diabetes. Long-chain fatty acids are released from triglycerides in lesions of atherosclerosis, and are esterified to CoA in order to be utilized by vascular cells through a reaction that is catalyzed by long-chain acyI-CoA synthetases (ACS1-5). Oleic acid (OA), the most common fatty acid in triglycerides, has important pro-atherosclerotic effects in vascular cells. Four questions will be addressed: 1. Which ACS isoforms are expressed in primary smooth muscle cells (SMCs) and macrophages, and are they regulated by glucose and lipids? We hypothesize that primary SMCs and macrophages express several ACS isoforms, and that their expression is differentially regulated by glucose and lipids in vitro and in vivo. For the in vivo studies, we have developed a new transgenic mouse model of diabetes-accelerated atherosclerosis. 2. Is ACS2 necessary for OA incorporation into phosphatidylcholine and generation of OA-enriched 1,2-diacylglycerol following growth factor stimulation in SMCs? OA enhances the mitogenic effects of growth factors in SMCs by generation of OA-enriched 1,2-diacylglycerol (1,2-DAG) following growth factor-stimulation of phospholipase D. We hypothesize that ACS2 mediates OA-incorporation into phosphatidylcholine and generation of OA-enriched 1,2-DAG following growth factor stimulation. We propose to inhibit ACS2 by using ACS inhibitors and RNAi. 3. Is ACS2 necessary for the ability of OA to enhance growth factor-induced proliferation in SMCs? We hypothesize that ACS2 is necessary for the ability of OA to enhance growth factor-induced proliferation in SMCs. Inhibitors of ACS isoforms and RNAi will be used to inhibit OA-mediated potentiation of mitogenic effects of growth factors. 4. Which specific ACS isoform(s) is necessary for OA-induced macrophage death and inhibition of cholesterol efflux? OA induces macrophage death and inhibits cholesterol efflux. We hypothesize that a specific ACS isoform is necessary for these events. ACS inhibitors and RNAi will be used to determine the ACS isoform that mediates OA-induced effects on macrophage death, cholesterol efflux and lipid metabolism. The ACS isoforms in vascular cells have not been studied to date. We expect to identify ACS isoforms required for important biological effects of OA in primary smooth muscle and macrophages.