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主要原因。动脉粥样硬化病变的发展被认为是跟随内侧平滑肌细胞（SMC）从收缩状态到合成状态的表型调节。已经确定了参与这种调节的各种信号，包括氧化应激、巨噬细胞起源的细胞因子和白细胞介素以及内皮因子（内皮素和一氧化氮）。血清高胆固醇血症作为危险因素的首要地位表明，分子胆固醇也可能在动脉粥样硬化中起作用。我们实验室的工作表明，SMC质膜中胆固醇的富集引起SMC的改变，与动脉粥样硬化非常相似。此外，这些改变可以被雌激素逆转。我们假设SMC质膜中胆固醇的富集是动脉粥样硬化过程中SMC调节的一个重要因素，而雌激素逆转这一作用的能力有助于其动脉粥样硬化保护作用。我们将用两个目标来检验这个假设。目的1将确定胆固醇改变SMC膜双层结构的能力，作为一个单一的、分离的和独立的变量，是否有助于动脉粥样硬化过程中SMC的表型和基因表达改变。目的2将确定雌激素的动脉粥样硬化保护作用是否介导A)直接在动脉SMC水平，B)雌激素的作用机制是否部分通过对抗胆固醇对动脉SMC膜的影响而介导。在这些研究中，我们将使用两种血管细胞制备方法：1。兔主动脉SMC早期通（等于或<3），2、人主动脉和冠状动脉SMC早期通（等于或<3）。随后将发生包括细胞增殖和胶原合成在内的表型改变。NFkappaB的激活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中间体进行测量。基因表达的改变将通过测量我们已经确定在SMC动脉粥样硬化过程中上调的2个基因（hn-RNP-K和脯氨酸-4-羟化酶）的信息和蛋白质水平，以及其他反映SMC、胶原I和III合成表型的基因来评估。结合这些方法，将为动脉粥样硬化过程中人类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必要的见解

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