CD45-mediated endothelial-to-mesenchymal transition in cardiovascular disease

项目总结/摘要 动脉粥样硬化是冠心病、缺血性中风和外周动脉粥样硬化的主要原因。 疾病这种进行性血管疾病仍然是美国死亡率的主要原因， 广泛使用有效的降脂治疗和预防计划。当内皮细胞活化时， 新生内膜增生是动脉粥样硬化发生和发展的标志， 内皮功能障碍的分子标志物是一种生物学挑战，也是一种机会， 开发新的治疗靶点。本研究旨在探讨内皮细胞表达的功能， CD 45与动脉粥样硬化CD 45是造血细胞的标志物。我们最近的数据显示， CD 45在驱动心肌缺血后的内皮-间质转化（EndMT）中是不可或缺的。 梗塞据认为，EndMT代表了一种新的内皮扰动和一种关键的调节因子， 动脉粥样硬化的发生，因为EndMT通过使内皮细胞分层而破坏内皮的正常功能 并产生新内膜间充质细胞，其分泌促炎分子和细胞外 促进动脉粥样硬化进展的基质蛋白。内皮细胞CD 45是否有助于 动脉粥样硬化通过促进EndMT是一个完全未知但非常重要的问题。是次调查被 在研究中，我们发现CD 45基因敲除小鼠注射动脉粥样硬化加速剂PCSK 9 AAv 8， 西方饮食明显减少了动脉粥样硬化的发生。相反地，我们观察到CD 45的显著增加， 在动脉粥样硬化病变中经历EndMT的阳性内皮细胞（EC）。我们还发现 CRISPR/Cas9介导的人EC中CD 45的活化诱导EndMT。有趣的是，CD 45表达 在HDAC 2敲除的生血内皮细胞中显著增加，表明HDAC 2介导的 EndMT过程中CD 45的抑制。此外，CD 45表达在miR-155缺陷小鼠中改变，表明 microRNA可能在EndMT过程中调节CD 45的表达和功能。我们的初步RNA测序研究显示， 在CD 45过表达时，epsins上调和KLF下调。鉴于胰蛋白酶促进和 KLF阻止动脉粥样硬化，无论是CD 45诱导EndMT还是通过调节 epsin和KLF功能是一个全新的问题。为了验证这一点，我们将确定内皮细胞的作用， CD 45在体内调节动脉粥样硬化中的作用及其分子机制的研究 CD 45通过控制epsin和KLF表达调节动脉粥样硬化中的EndMT; 2） EndMT过程中内皮细胞中CD 45表达的表观遗传学调控以及靶向内皮细胞CD 45 促进动脉粥样硬化消退。我们的初步数据提供了强有力的证据， 这是我们研究的前提。如果成功的话，我们的研究将不仅提供广泛的机械证据， CD 45介导的信号传导在调节EndMT中的核心作用，但将提供一种创新的方法， 用于治疗动脉粥样硬化，并启动对抗心血管疾病研究的范式转变。

PROJECT SUMMARY/ABSTRACT Atherosclerosis is the primary cause of coronary heart disease, ischemic stroke, and peripheral arterial disease. This progressive vascular disease remains a leading cause of mortality in the United States despite wide-spread use of effective lipid-lowering therapies and prevention programs. While endothelial cell activation and neointimal hyperplasia is a hallmark of the initiation and progression of atherosclerosis, identification of molecular markers of dysfunctional endothelium represents a biological challenge as well as an opportunity to develop new therapeutic targets. In this application, we posit to explore the function of endothelial expressed CD45 in atherosclerosis. CD45 is best known as marker of hematopoietic cells. Our recent data shows that CD45 is indispensable in driving the endothelial-to-mesenchymal transition (EndMT) following myocardial infarction. It is thought that EndMT represents a novel endothelial perturbation and a critical regulator of atherogenesis given that EndMT disrupts the normal function of endothelium by delaminating endothelial cells and giving rise to neointimal mesenchymal cells, which secrete proinflammatory molecules and extracellular matrix proteins that fuel atherosclerosis progression. Whether endothelial CD45 contributes to progression of atherosclerosis by facilitating the EndMT is a completely unknown but highly significant question. In our latest studies, we showed CD45 null mice injected with the atherosclerosis accelerator PCSK9 AAv8 and fed a western diet had a marked reduction in atherogenesis. Conversely, we observed a significant increase in CD45 positive endothelial cells (ECs) that undergo the EndMT in atherosclerotic lesions. We also found that CRISPR/Cas9-mediated activation of CD45 in human ECs induces the EndMT. Intriguingly, CD45 expression is dramatically increased in HDAC2 knockout hemogenic endothelium, suggesting loss of HDAC2-mediated repression of CD45 during EndMT. Further, CD45 expression is altered in miR-155 deficient mice, indicating microRNAs may regulate the expression and function of CD45 during EndMT. Our pilot RNA seq study shows upregulation of epsins and downregulation of KLFs upon CD45 overexpression. Given that epsins promote and KLFs impede atherosclerosis, whether CD45 induces EndMT and promotes atherosclerosis by modulating epsin and KLF function is an entirely novel question. To test this, we will determine the role of endothelial CD45 in regulating atherosclerosis in vivo and interrogate molecular mechanisms 1) by which endothelial CD45 regulates EndMT in atherosclerosis by controlling epsin and KLF expression and 2) underlying how CD45 expression is epigenetically regulated in ECs during EndMT and whether targeting endothelial CD45 promotes atheroma resolution. Our preliminary data presents robust evidence that serves as a strong scientific premise for our proposed study. If successful, our study will not only provide extensive mechanistic evidence for a central role of CD45-mediated signaling in regulating the EndMT, but will provide an innovative approach for the treatment of atherosclerosis and launch a paradigm shift in research to combat cardiovascular disease.