Lipid Transfer Mechanisms

描述(申请人提供)：高密度脂蛋白(HDL)是一种 心血管疾病的负面(保护性)危险因素。已经有了 血浆因子对高密度脂蛋白重塑的影响 为了心脏保护。人血浆中的一种磷脂转移蛋白 高密度脂蛋白重塑过程中的关键蛋白质。尽管最近的研究表明 PLTP即使在没有其他血浆的情况下也能改变高密度脂蛋白的结构和组成 这些因素，其发生的机制仍有待阐明。我们 提出三个目标，以检验有关重建的八个假设 机制。具体内容如下：目标1：明确S的作用机制 PLTP根据以下假设重塑高密度脂蛋白：A]重塑 高密度脂蛋白是载脂蛋白A-I的特异体。B]PLTP非依赖的高密度脂蛋白融合 通过高密度脂蛋白表面的疏水补丁发生。C]HDL3融合，它 遵循PLTP介导的载脂蛋白A-I释放和贴片形成，不依赖于 PLTP。D]融合但不是脂类转移被净阳性或 高密度脂蛋白上的负电荷。由PLTP形成的小的高密度脂蛋白是优先的 胆固醇的受体和LCAT的首选底物。F]磷脂 转移是胆固醇酯转移的必备前体。目标2：实现 确定PLTP分子转移特异性的决定因素。这一目标将 解决了PLTP的分子特异性由以下因素决定的假设 它与单体脂的亲和力和结合力。目标3：确定影响 PLTP对血浆脂蛋白与巨噬细胞来源相互作用的影响 脂蛋白。这一目标将解决PLTP是关键介体的假设 巨噬细胞来源的脂蛋白与更成熟形式的 高密度脂蛋白。将采用的主要技术是定点突变、分析 卵磷脂：胆固醇酰基转移酶和磷脂酶活性，组织 培养(P388D_1巨噬细胞)、平衡测量及脂肪和蛋白质 化验。

DESCRIPTION (provided by applicant): High-density lipoproteins (HDL) are a negative (protective) risk factor for cardiovascular disease. There has been great interest in how the remodeling of HDL by plasma factors might contribute to cardioprotection. A phospholipid transfer protein (PLTP) in human plasma is a key protein in the remodeling of HDL. Although recent studies have shown that PLTP modifies HDL structure and composition even in the absence of other plasma factors, the mechanism by which this occurs remains to be elucidated. We propose three aims that will test eight hypotheses concerning the remodeling mechanism. They are as follows: Aim 1: To identify the mechanism(s) by which PLTP remodels HDL, according to the following hypotheses: a] The remodeling of HDL is specific for apolipoprotein (apo) A-I. b] PLTP-independent HDL fusion occurs through a hydrophobic patch on the HDL surface. c] HDL3 fusion, which follows PLTP-mediated apo A-I release and patch formation, is independent of PLTP. d] Fusion but not lipid transfer is inhibited by a net positive or negative charge on HDL. e] The small HDL formed by PLTP are preferential acceptors for cholesterol and a preferred substrate for LCAT. f] Phospholipid transfer is an obligatory precursor of cholesteryl ester transfer. Aim 2: To identify the determinants of PLTP molecular transfer specificity. This aim will address the hypothesis that the molecular specificity of PLTP is determined by its affinity for and binding to monomeric lipid. Aim 3: To identify the effects of PLTP on the interaction of plasma lipoproteins with macrophage-derived lipoproteins. This aim will address the hypothesis that PLTP is a key mediator of the association of macrophage-derived lipoproteins with more mature forms of HDL. The major techniques to be employed are site-directed mutagenesis, assays of lecithin:cholesterol acyltransferase and phospholipase activity, tissue culture (P388D1 macrophages), equilibrium measurements and lipid and protein assays.