Apoj/Clusterin:A Protective Protein In Vascular Biology

描述（由申请方提供）：血管再闭塞仍然是支架置入术的一种严重并发症：30-50%的受试者在血管手术后1年内发生血管再闭塞。支架内再狭窄主要是由于平滑肌细胞的新生内膜增生。因此，了解新生内膜增生的机制和生化参与者将优化干预方案的设计，降低血管手术后再狭窄的风险。我们的初步结果表明，载脂蛋白（apo）J / clusterin可能是一个重要的调节器，在确定血管反应的损伤和发展的新生内膜病变。以遗传学定义的小鼠为模型，我们的研究结果表明，apoJ的表达是诱导响应机械损伤的颈动脉。重要的是，与野生型小鼠相比，apoJ（-/-）小鼠在动脉损伤后2周发生了更严重的新生内膜病变。此外，额外的初步结果表明，与喂食相同的富含胆固醇的致动脉粥样硬化饮食的apoJ野生型小鼠相比，apoJ（-/-）小鼠发生增加的高胆固醇血症。这种高胆固醇血症与脂蛋白颗粒中apoE分布的改变有关。因此，目前的研究使用体内小鼠模型来测试apoJ通过调节一个或多个导致血管闭塞性疾病的主要事件而在体内具有直接血管保护功能的假设。具体目标1包括三个部分。首先，比较野生型和apoJ（-/-）小鼠中从血管损伤时间到新生内膜形成时间的事件顺序。观察到血管病理学差异的时间与野生型小鼠中apoJ的时间表达相关。以这些数据为指导，第二部分进行基因表达谱研究，以确定在血管损伤反应中由apoJ调节的生物和功能途径。第三部分使用apoJ-tg小鼠和腺病毒介导的apoJ基因直接转移到血管壁来测试推论假设，即增加apoJ表达是限制新内膜增生的可行策略。特定目的2检验了以下假设：apoJ缺乏通过改变apoE在脂蛋白中的分布来降低脂蛋白催化剂，从而加剧饮食诱导的高胆固醇血症。我们将描述apoJ野生型和apoJ（-/-）小鼠中VLDL颗粒的代谢：定量catalysts，定量脂蛋白合成和分泌，以及定量apoE从HDL向VLDL的转移。在Specific Aim 3中，给野生型、apoJ（-/-）和apoJ-tg小鼠喂食富含胆固醇的致动脉粥样硬化饮食，以测试apoJ也对进行性动脉粥样硬化具有保护作用的假设。总之，这些研究将确定新的功能，载脂蛋白J以及有助于我们更好地了解血管损伤反应的致病事件。

DESCRIPTION (provided by applicant): Vascular reocclusion remains a significant complication of stent placement: vascular reocclusion occurs in 30-50% of subjects within 1 year of vascular surgery. In-stent restenosis is due primarily to neointima hyperplasia of smooth muscle cells. Thus, understanding the mechanism(s) and biochemical participants in neointima hyperplasia will optimize the design of intervention protocols that reduce the risk of restenosis after vascular surgery. Our Preliminary Results suggest that apolipoprotein (apo) J / clusterin may be an important regulator in determining the vascular response to injury and the development of the neointima lesion. With genetically defined mice as the model, our results show that apoJ expression is induced in response to mechanical injury of the carotid artery. Importantly, apoJ(-/-) mice developed a more severe neointima lesion 2 wk after arterial injury in comparison to wild type mice. Moreover, additional Preliminary Results demonstrate that apoJ(-/-) mice develop increased hypercholesterolemia compared to apoJ wild type mice fed the same cholesterol enriched atherogenic diet. This hypercholesterolemia is associated with an altered distribution of apoE among lipoprotein particles. Therefore, the current study uses the in vivo mouse model to test the hypothesis that apoJ has a direct vascular protective function in vivo by modulating one or more of the cardinal events that contribute to vascular occlusive disease. Specific Aim 1 contains three parts. First, the sequence of events from the time of vascular injury to the time of neointima formation in wild type and apoJ(-/-) mice is compared. The time when differences in vascular pathology are observed is correlated with the temporal expression of apoJ in wild type mice. With these data as a guide, the second part performs gene expression profiling studies to determine the biologic and functional pathways that are modulated by apoJ in the vascular response to injury. The third part uses apoJ-tg mice and adenovirus mediated apoJ gene transfer directly to the vessel wall to test the corollary hypothesis that increased apoJ expression is a viable tactic to limit neointirna hyperplasia. Specific Aim 2 tests the hypothesis that apoJ deficiency exacerbates diet induced hypercholesterolemia by decreasing lipoprotein catabolism via alteration of apoE distribution among lipoproteins. We will characterize the metabolism of VLDL particles in apoJ wild type and apoJ(-/-) mice: quantify catabolism, quantify lipoprotein synthesis and secretion, and quantify transter of apoE from HDL to VLDL. In Specific Aim 3 wild type, apoJ(-/-), and apoJ-tg mice are fed a cholesterol enriched atherogenic diet to test the hypothesis that apoJ is protective, also, against progressive atherosclerosis. Taken together, these studies will identify novel functions of apoJ as well as contribute to our better understanding of the pathogenic events in the vascular response to injury.