SMOOTH MUSCLE CELL MEMBRANE DURING ATHEROGENESIS

在西方文化中，动脉粥样硬化仍然是导致死亡的唯一主要原因。动脉粥样硬化病变的发展被认为是遵循中膜平滑肌细胞（SMC）从收缩到合成状态的表型调节。已经鉴定了似乎参与这种调节的多种信号，包括氧化应激、巨噬细胞来源的细胞因子和白细胞介素以及内皮因子（内皮素和NO）。血清高胆固醇血症作为一个危险因素的首要地位表明，胆固醇分子也可能在动脉粥样硬化形成中发挥作用。我们实验室的工作表明，富含胆固醇的SMC质膜诱导SMC发生与动脉粥样硬化非常相似的改变。此外，这些改变被雌激素逆转。我们推测，富含胆固醇的SMC质膜是动脉粥样硬化形成过程中SMC调节的一个重要因素，雌激素逆转这种作用的能力有助于其动脉粥样硬化保护作用。我们将在两个目标中测试这个假设。目的探讨胆固醇改变SMC膜双层结构的能力是否作为一个单一的、孤立的和独立的变量，在动脉粥样硬化形成过程中对SMC表型和基因表达的改变有贡献。目的2将确定雌激素的动脉粥样硬化保护作用是否是直接在动脉SMC水平介导的A）和B），雌激素的作用机制是否部分通过对抗胆固醇对动脉SMC膜的作用来介导。对于这些研究，我们将采用两种血管细胞制备物：1.兔主动脉SMC早期传代（等于或<3）; 2人主动脉和冠状动脉SMC早期传代（等于或<3）。将跟踪表型改变，包括细胞增殖和胶原蛋白合成。NF κ B活化和活性氧中间体的产生将使用适当的技术作为潜在的信号传导中间体进行测量。将通过测量我们已确定在动脉粥样硬化形成期间在SMC中上调的2种基因（hn-RNP-K和脯氨酰-4-羟化酶）以及其他人确定的反映SMC中合成表型的基因（胶原蛋白I和III）的信息和蛋白水平来评估基因表达的变化。结合这些方法将为动脉粥样硬化形成期间人类SMC早期缺陷的细胞基础以及雌激素如何在这种疾病中提供细胞保护提供重要见解

Atherosclerosis continues to be the single leading cause of mortality in Western cultures. The development of atherosclerotic lesions is thought to follow the phenotypic modulation of medial smooth muscle cells (SMC) from the contractile to the synthetic state. A variety of signals have been identified that appear to participate in this modulation including oxidative stress, cytokines and interleukins of macrophage origin and endothelial factors (endothelins and NO.). The primacy of serum hypercholesterolemia as a risk factor suggests that the molecule cholesterol may also play a role in atherogenesis. Work performed by our lab has shown that enrichment of the SMC plasma membrane with cholesterol induces alterations in SMC very similar to those seen in atherosclerosis. Moreover, these alterations are reversed by estrogen. We hypothesize that enrichment of the SMC plasma membrane with cholesterol is an important factor contributing to SMC modulation during atherogenesis, and that estrogen's ability to reverse this effect contributes to its atheroprotective actions. We will test this hypothesis in 2 aims. Aim l will determine whether cholesterol's ability to alter the SMC membrane bilayer structure, as a single, isolated and independent variable contributes to the phenotypic and gene expression alterations in SMC during atherogenesis. Aim 2 will determine whether the atheroprotective effects of estrogen are mediated A), directly at the level of the arterial SMC and B), whether the mechanism of estrogen's actions are mediated, in part, by countering cholesterol's effects on the arterial SMC membrane. For these studies,we will employ two preparations of vascular cells: 1. early passage (equal to or <3) rabbit aortic SMC, and 2, early passage (equal to or <3) human aortic and coronary artery SMC. Phenotypic alterations will be followed including cell proliferation and collagen synthesis. NFkappaB activation and the generation of reactive oxygen intermediates will be measured as potential signaling intermediates using appropriate techniques. Alterations in gene expression will be assessed by measuring message and protein levels for 2 genes we have identified to be upregulated in SMC during atherogenesis (hn-RNP-K and prolyl-4-hydroxylase) as well as genes identified by others reflecting the synthetic phenotype in SMC, collagens I and III. Combining these approaches will provide essential insights into the cellular basis for the early defects in human SMC during atherogenesis and how estrogen provides cellular protection in this disease