AIBP-Mediated Cholesterol Efflux and Angiogenesis

项目摘要 心肌梗死是美国死亡率和发病率的主要原因。再灌注后， 血管生成和微循环的恢复是正常心脏恢复的关键组成部分， 功能血管生成对斑马鱼心脏再生也很重要。取得了很大进展 对血管生成的分子机制的理解，但新陈代谢之间的联系， 血管生成的研究较少。我的初步研究强烈表明，胆固醇流出， 内皮细胞调节血管生成。我发现体外和胚胎斑马鱼的血管生成 受ApoA-I结合蛋白（AIBP）调节，AIBP是一种分泌蛋白，在蛋白质筛选中鉴定， 与ApoA-I相关。AIBP加速ABCG 1介导的胆固醇从内皮细胞（EC）流出， 体外此外，AIBP控制胚胎斑马鱼节段动脉（SeA）的形成。 过表达AIBP抑制SeA发芽，而AIBP敲低则导致SeA表达失调。 发芽和分枝。在我指导的K99阶段，我建议测试分泌AIBP的假设， 作为EC胆固醇流出的位点特异性调节剂发挥作用，并支配胚胎血管生成。首先我 计划证明AIBP介导的ABC转运蛋白依赖的胆固醇流出调节胚胎发育。 斑马鱼的血管生成我发现AIBP缺失所导致的表型被表型复制， 细胞胆固醇转运蛋白ABCA 1和ABCG 1的敲低。我的目标是证明， AIBP对胚胎血管生成的影响依赖于AIBP在胆固醇代谢中的作用。这些研究 将建立一种以前未被认识的机制，将胆固醇流出与胚胎发育联系起来。 血管生成然后在我的独立R 00阶段，我将证明AIBP在成人中的过度表达， 斑马鱼减弱心脏再生。冠状动脉血管的形成被认为是重要的 心脏再生，因为它可以想象提供了必要的资源， 心肌细胞本研究将建立AIBP条件表达转基因鱼系，并研究AIBP对鱼体生长的影响。 AIBP过表达对斑马鱼心脏再生过程中发生的血管生成的影响。我的第二个目标 独立R 00期是为了评估AIBP表达调节小鼠中冠状动脉血管生成。因为 我的研究结果表明AIBP限制了血管生成，我认为心肌细胞特异性AIBP的丢失将 在心脏肥大的情况下促进血管生成。这些研究将阐明 AIBP控制的心脏再生和心脏肥大中的血管生成，并提示可能的 通过促进血管生成来刺激微血管恢复的治疗干预。

Project Summary Myocardial infarction is the leading cause of mortality and morbidity in the US. Following reperfusion, angiogenesis and restoration of microcirculation is a critical component in the recovery of normal cardiac function. Angiogenesis is also important for zebrafish heart regeneration. Much progress has been made towards understanding of the molecular mechanisms of angiogenesis, but the connection between metabolism and angiogenesis is less studied. My preliminary studies strongly suggest that cholesterol efflux from endothelial cells regulates angiogenesis. I found that angiogenesis in vitro and in embryonic zebrafish was regulated by ApoA-I binding protein (AIBP), a secreted protein identified in a screen of proteins that physically associate with ApoA-I. AIBP accelerated ABCG1-mediated cholesterol efflux from endothelial cells (EC) in vitro. Furthermore, AIBP controlled formation of segmental arteries (SeA) in embryonic zebrafish. Overexpression of AIBP inhibited SeA sprouting, while AIBP knockdown resulted in dysregulated SeA sprouting and branching. In my mentored K99 phase, I propose to test the hypothesis that secreted AIBP functions as a site-specific regulator of cholesterol efflux from EC and governs embryonic angiogenesis. First, I plan to demonstrate that AIBP-mediated, ABC transporters-dependent cholesterol efflux regulates embryonic angiogenesis in zebrafish. I found that the phenotype caused by the loss of AIBP was phenocopied by knockdown of cellular cholesterol transporters ABCA1 and ABCG1. My goal in this Aim is to prove that the effect of AIBP on embryonic angiogenesis relies on the AIBP function in cholesterol metabolism. These studies will establish a previously unrecognized mechanism connecting cholesterol efflux with embryonic angiogenesis. Then in my independent R00 phase, I will demonstrate that AIBP overexpression in adult zebrafish attenuates heart regeneration. Formation of coronary vasculature is believed to be important for heart regeneration because it conceivably provides resources necessary for robust proliferation of cardiomyocytes. I will make an AIBP conditional expression transgenic fish line, and investigate the impact of AIBP overexpression on angiogenesis that occurs during zebrafish heart regeneration. My second Aim in the independent R00 phase is to assess that AIBP expression modulates coronary angiogenesis in mice. Because my results suggest that AIBP limits angiogenesis, I propose that cardiomyocyte-specific loss of AIBP would promote angiogenesis under conditions of cardiac hypertrophy. These studies will elucidate a potential role for AIBP-governed angiogenesis in heart regeneration and in cardiac hypertrophy and suggest possible therapeutic interventions to stimulate the recovery of the microvasculature by promoting angiogenesis.