ROLE OF MACROPHAGE RECEPTORS FOR OXLDL IN ATHEROGENESIS

拟议研究的长远目标是改善我们的 了解脂蛋白-巨噬细胞相互作用可能 有助于泡沫细胞的形成和动脉粥样硬化的形成。强调将 被放置在乙酰低密度脂蛋白受体(SRA)上，hCD36及其小鼠 同系物(MDC36)和一个94-97 kDa的氧化低密度脂蛋白(OxLDL)- 我们已有的小鼠腹膜巨噬细胞结合蛋白 以前被描述为大唾液酸，现在被鉴定为大唾液酸钾。 Macrosialin和它的人类同源物dc68，以前都是 克隆，主要发现在晚期的内体部分和 它们的功能尚不清楚。我们建议研究它们的运输 在亚细胞室之间，制备稳定转染的细胞 为了表征它们的配基结合特性，识别配基 通过制备嵌合蛋白和按位置结合结合部位- 定向诱变，并制备mcarosialin基因敲除小鼠 确定巨噬细胞的表型后果 功能、免疫功能与动脉粥样硬化形成。CD36，一家老牌的 氧化低密度脂蛋白结合受体在结合和吞噬中的作用 与Vitronectin受体协同作用的凋亡细胞 凝血酶敏感蛋白。我们将检验以下假设： 氧化低密度脂蛋白可能受这种相互作用的调节。使用单元格 从SRA基因敲除小鼠(T.KoDama博士的礼物)，我们将 评估该受体在体外和体外氧化低密度脂蛋白代谢中的作用 活着。最后，我们将继续在 非洲爪哇卵母细胞寻找额外的巨噬细胞蛋白 可能参与摄取氧化低密度脂蛋白或/和受损或 凋亡性细胞。已经分离出五个克隆。没有一个 它们代表SRA、mCD36或大唾液酸。这些遗嘱 被测序和刻画。

The long term goal of the proposed studies is to improve our understanding of lipoprotein-macrophage interactions that may contribute to foam cell formation and atherogenesis. Emphasis will be placed on the acetyl LDL receptor (SRA), hCD36 and its mouse homologue (mDC36), and a 94-97 kDa oxidized LDL (OxLDL)- binding protein from mouse peritoneal macrophages which we have previously characterized and have now identified as macrosialin. Macrosialin and its human homologue, DC68, both previously clones, are found predominantly in the late endosomal fraction and their functions are not known. We propose to study their transport between subcellular compartment, to prepare stably transfected cells to characterize their ligand-binding properties, identify ligand binding sites by preparation of chimeric proteins and by site- directed mutagenesis, and prepare a mcarosialin knockout mouse to ascertain phenotypic consequences with regard to macrophage function, immune function and atherogenesis. CD36, an established OxLDL-binding receptor, functions in the binding and phagocytosis of apoptotic cells in cooperation with the vitronectin receptor and thrombospondin. We will test the hypothesis that binding of OxLDL may be modulated by interactions of this kind. Using cells from the SRA knockout mouse (gift of Dr. T. Kodama), we will assess the role of the receptor in OxLDL metabolism in vitro and in vivo. Finally, we will continue to use expression cloning in Xenopus oocytes to search for additional macrophage proteins that may participate in uptake of OxLDL or/and of damaged or apoptotic cells. Five clones have already been isolated. None of them represents either SRA, mCD36, or macrosialin. These will be sequenced and characterized.