Mechanisms of Fibronectin Extra Domain A in Atherosclerosis

描述(由申请人提供)：冠状动脉疾病是美国和世界范围内死亡和残疾的主要原因，也是不断上升的医疗费用的原因。在临床上，斑块破裂是冠状动脉血栓形成的最重要原因，通常与心肌梗死和死亡有关。许多在斑块破裂中起关键作用的内源性配体仍未被很好地了解。细胞外基质蛋白纤维连接蛋白的一个变异体含有选择性剪接的额外结构域A(EDA+-FN)，在健康的动脉中缺失，但在人类动脉粥样硬化的动脉中表达，提示在动脉粥样硬化的病理生理学中发挥了作用。我们最近使用一种特异性抑制剂的研究表明，EDA+-FN通过Toll样受体4(TLR4)途径加重脑缺血/再灌注性损伤。总之，这些发现为测试EDA+-FN和TLR4信号在调节早期和晚期动脉粥样硬化中的新作用提供了令人信服的理论基础。在目标1中，我们将验证EDA+-FN通过TLR4信号在载脂蛋白E缺陷(ApoE-/-)小鼠中加剧早期动脉粥样硬化的假说。进一步，我们将确定内皮细胞TLR4在加剧早期动脉粥样硬化中的作用。在目标2中，我们将验证TLR4信号与ApoE-/-小鼠晚期动脉粥样硬化斑块易损性有关的假设。进一步，我们将检验EDA+-FN通过TLR4信号促进斑块易损性的假设。在目标3中，我们将确定内皮细胞EDA+-FN在动脉粥样硬化中的作用。作为一种临床前方法，我们将测试用单抗阻断EDA+-FN将抑制ApoE-/-小鼠动脉粥样硬化病变进展的假设。拟议的研究将使用多学科的创新方法，包括几个新的遗传小鼠品系，以及一种新的体内方法来确定EDA+-FN调节动脉粥样硬化的机制。这一建议意义重大，可能具有重要的临床意义，因为本文设计的研究将确定一种新的内源性配体，并揭示在早期和促进病变发展中调节关键动脉粥样硬化事件的新途径。

DESCRIPTION (provided by applicant): Coronary artery disease is a major cause of mortality and disability in the United States and worldwide, and accounts for rising health costs. Clinically it is evident that plaque rupture, the most important cause of coronary thrombosis, is often associated with myocardial infarction and death. Many of the endogenous ligands that play a key role in plaque rupture are still not well understood. A variant of the extracellular matrix protein fibronectin containing the alternatively-spliced extra domain A (EDA+-FN) is absent in healthy arteries, but expressed in the atherosclerotic arteries of humans, suggesting a role in the pathophysiology of atherosclerosis. Our recent study using a specific inhibitor suggests that EDA+-FN aggravates ischemia/reperfusion brain injury via toll-like-receptor 4 (TLR4) pathway. Together these findings provide a compelling rationale to test the novel role of EDA+-FN and TLR4 signaling in modulating early and advanced atherosclerosis. In Aim 1, we will test the hypothesis that EDA+-FN exacerbates early atherosclerosis via TLR4 signaling in apolipoprotein E-deficient (ApoE-/-) mice. Further, we will define the role of endothelial cell TLR4 in exacerbating early atherosclerosis. In Aim 2, we will test the hypothesis that TLR4 signaling contributes to plaque vulnerability during advanced atherosclerosis in ApoE-/- mice. Further, we will test the hypothesis that EDA+-FN promotes plaque vulnerability via TLR4 signaling. In Aim 3, we will define the role of endothelial cell EDA+-FN in atherosclerosis. As a preclinical approach, we will test the hypothesis that blocking EDA+-FN with monoclonal antibodies will inhibit atherosclerotic lesion progression in ApoE-/- mice. The proposed studies will use multidisciplinary innovative approaches, including several novel genetic mouse strains, and a novel intravital method to define the mechanisms by which EDA+-FN modulates atherosclerosis. The proposal is significant and may have important clinical implications because the studies designed herein will identify a novel endogenous ligand and unravel new pathway that modulate key atherogenic events in early and advance lesion development.