Mechanisms of Aortic Fibrosis

主动脉纤维化的机制

• 批准号: 6781657
• 负责人: Herbert Marcus Kagan
• 金额: $ 24.34万
• 依托单位: BOSTON UNIVERSITY MEDICAL CAMPUS
• 依托单位国家: 美国
• 财政年份: 2003
• 资助国家: 美国
• 起止时间: 2003-12-01 至 2008-11-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/6781657
• 关键词: amine oxidoreductase; atherosclerosis; biological signal transduction; cell surface receptors; chemotaxis; clinical research; collagen; enzyme mechanism; gene expression; histones; immunocytochemistry; in situ hybridization; laboratory mouse; laboratory rat; lysine; protein localization; receptor binding; tissue /cell culture; vascular smooth muscle

The activation, migration, proliferation and abundant matrix synthesis by the normally quiescent medial vascular smooth muscle cell (VSMC) are central events in the development of atherosclerotic lesions. Our recent findings have revealed that lysyl oxidase (LO), the extracellular enzyme which oxidizes peptidyl lysine to initiate the covalent crosslinking and insolubilization of soluble forms of elastin and collagen, plays previously unexpected roles strongly influencing the behavior of VSMC. We have found that LO is strongly chemotactic for VSMC and that it binds to a surface receptor of these cells indicated by our preliminary results to contain a beta1 integrin subunit. Following binding to the VSMC surface, LO enters the cell and then concentrates within the cell nucleus. We have also found that histone H1 is oxidized within VSMC nuclei by endogenous LO. These events are accompanied by increased production of collagen and phosphorylation of intracellular signaling proteins. Our guiding hypothesis is that LO may serve as an important activator of VSMC functions, acting both as an extracellular and intracellular signal stimulating phenotypic changes in the VSMC as in arterial disease. Specific Aims of this project are: (1) Elucidate the mechanism and significance of LO binding to plasma membrane receptors. We will identity the VSMC membrane proteins acting as holoreceptor(s) of LO and assess their roles in the responses of VSMC to LO binding, uptake, and activation of signal transduction pathways. (2) Elucidate the nature of the nuclear modifications catalyzed by LO and the potential consequences on gene expression. We will identify nuclear proteins which can be oxidized by nuclear LO and assess for the effect of LO on the transcription of specific collagen genes of VSMC. (3) Characterize the expression, intraeellular and extracellular localization and abundance of LO in VSMC in response to vascular injury. Immunocytochemistry and in situ transcription assays will be used to probe for the expression and intra- and extracellular localization of LO within normal vascular tissue and in vascular lesions induced in a rat femoral artery injury model. Taken together, these studies will explore mechanisms by which LO may influence activities of the VSMC that occur in atherosclerosis.

正常静止状态下的中膜血管平滑肌细胞（VSMC）的活化、迁移、增殖和丰富的基质合成是动脉粥样硬化病变发展的中心事件。我们最近的研究结果表明，赖氨酰氧化酶（LO），细胞外酶的氧化肽基赖氨酸启动共价交联和不溶性形式的弹性蛋白和胶原蛋白，发挥以前意想不到的作用，强烈影响VSMC的行为。我们已经发现，LO是强烈的趋化性VSMC，它结合到这些细胞的表面受体，我们的初步结果表明，包含β 1整合素亚基。在与VSMC表面结合后，LO进入细胞，然后集中在细胞核内。我们还发现组蛋白H1在VSMC细胞核内被内源性LO氧化。这些事件伴随着胶原蛋白的产生增加和细胞内信号蛋白的磷酸化。我们的指导假设是，LO可能作为一个重要的激活剂的VSMC功能，作为细胞外和细胞内信号刺激表型变化的VSMC在动脉疾病。本课题的具体目的是：（1）阐明LO与质膜受体结合的机制及意义。我们将鉴定作为LO全受体的VSMC膜蛋白，并评估它们在VSMC对LO结合、摄取和激活信号转导通路的反应中的作用。(2)阐明LO催化的核修饰的性质以及对基因表达的潜在影响。我们将确定核蛋白，可以被氧化的核LO和评估的影响，LO对特定的胶原基因的VSMC的转录。(3)研究血管损伤后VSMC中LO的表达、细胞内外定位和丰度。将使用免疫细胞化学和原位转录测定来探测LO在正常血管组织和诱导的血管病变中的表达和细胞内和细胞外定位。 在大鼠股动脉损伤模型中。总之，这些研究将探讨LO可能影响动脉粥样硬化中发生的VSMC活动的机制。