SMOOTH MUSCLE CELL PROLIFERATION AND ATHEROSCLEROSIS

动脉粥样硬化是一个复杂的病理过程，由 遗传因素和环境因素的相互作用。很多人 在没有已知危险因素的情况下发生加速的动脉粥样硬化， 有人提出，有些人可能是遗传上的 易发展为动脉粥样硬化的机制 在动脉壁的水平。血管内皮细胞增殖的研究 动脉内膜在血管的生长发育中起着关键的作用。 动脉粥样硬化病变。在拟议的研究中，假设是 测试表明，动脉粥样硬化的遗传易感性 管壁水平包括平滑肌的不同增殖反应 通过调节分子硫酸乙酰肝素表现出来的细胞 蛋白多糖(HSPG)。由于可获得性，这些研究是可能的 遗传选择的动脉粥样硬化易感白斑(WC)和 -抵抗显示赛马(SR)鸽子。培养的主动脉平滑肌细胞 的鸽子表现出比那些 关于SR的。细胞表面HSPG的研究显示WC患者HSPG减少 与SR细胞相比。WC表面残留的HSPG较低 硫酸化的八糖，一种独特的二糖含量很低 含有艾杜糖酸2-O-SO3。当WC HSPG被隔离并添加到 WC或SR在培养的平滑肌细胞中，具有低的抗增殖作用 观察到的。SR-HSPG抑制SR细胞的增殖 对WC细胞有效。建议的研究旨在确定 导致WC细胞HSPG减少的机制。基于初步的 在工作中，WC细胞产生一池细胞表面的HSPG，该池被运输到 细胞表面但很快就消失了。乙酰肝素酶和肝素酶的可能作用 这种缺失中的蛋白水解酶将在细胞培养研究中进行探索 定义一种可能是WC单元独有的机制。直通脉冲追逐 和动力学模型，新陈代谢和细胞通路参与 将对快速翻转的HSPG池进行检查。的研究 细胞表面低聚糖的HSPG结果表明， 热休克蛋白的抗增殖作用与细胞周期改变有关 低聚糖序列和二次修饰(例如，硫酸盐化和 位置)。拟议的研究将检查N-脱乙酰酶/N的活性 硫酸盐生产中的关键酶--磺基转移酶 阻断HS中的寡糖以确定是否存在结构变化 WC HS的糖类主要来源于酶活性的差异性。这个 该提案的最终目标是确定HSPG在 动脉粥样硬化等情况下的平滑肌细胞增殖 作为临床血管成形术后的再狭窄。

Atherosclerosis is a complex pathological process that results from an interplay of genetic and environmental components. Many human beings develop accelerated atherosclerosis in the absence of known risk factors, and it has been proposed that some individuals may be genetically predisposed to develop atherosclerosis as a result of mechanisms Operating at the level of the arterial wall. Proliferation of smooth muscle cells in the arterial intima is of key importance in the development and growth of atherosclerotic lesions. In the proposed studies the hypothesis to be tested is that genetic susceptibility to atherosclerosis at the artery wall level includes a differential proliferative response of smooth muscle cells manifested through a regulatory molecule heparan sulfate proteoglycan (HSPG). The studies are possible because of the availability of genetically selected atherosclerosis-susceptible White Carneau (WC) and -resistant Show Racer (SR) pigeons. Cultured aortic smooth muscle cells of the WC pigeons demonstrate a greater proliferation capacity than those of SR. Studies of cell surface HSPG have demonstrated reduced HSPG in WC compared to SR cells. The HSPG remaining on the surface of WC have low sulfated octasaccharide and possess a low content of a unique disaccharide containing iduronic acid 2-O-SO3. When WC HSPG are isolated and added to WC or SR smooth muscle cells in culture, a low antiproliferative effect is observed. SR HSPG block the proliferation of SR cells and are less effective in WC cells. The studies proposed are designed to determine the mechanisms that result in reduced HSPG on WC cells. Based on preliminary work, WC cells produce a pool of cell surface HSPG which is transported to the cell surface but rapidly lost. Possible roles of heparanases and proteinases in this loss will be explored in cell culture studies to define a mechanism that may be unique to the WC cells. Through pulse chase and kinetic modeling, the metabolism and cellular pathways involved in the fast-turning-over pool of HSPG will be examined. Studies of oligosaccharides of cell surface HSPG indicated that the reduced antiproliferative effect of HSPG resulted from the alterations in oligosaccharide sequences and secondary modifications (e.g., sulfation and position). Proposed studies will examine the activity of N-deacetylase/N sulfotransferase, the pivotal enzyme in the production of sulfated oligosaccharide blocks in HS to determine if structural variations in the saccharides of WC HS are attributed to differential enzyme activity. The ultimate goal of the proposal is to determine the role of HSPG in relation to smooth muscle cell proliferation in atherosclerosis and conditions such as restenosis following clinical angioplasty.