This multidisciplinary renewal probes mechanism in atherogenesis, emphasizing those cells implicated in pathogenesis, namely EC, SMC, and the mononuclear phagocyte (MP). After major revisions, including the deletion of one project, and the complete restructuring of another, the more focused PROGRAM PROJECT comprises 4 complementary projects and 4 core units. PROJECT A employs a parallel plate channel flow viscometric device to explore biologic responses of vascular EC to steady state and oscillatory laminar shear stress, emphasizing changes in cell stiffness, intracellular potential and LDL and Ac-LDL receptor expression and function. Mechanisms of hemodynamic signal transduction are examined with emphasis on EC membrane fluidity (DPH), phosphoinositide turnover, Ca++ mobilization (Fura 2), and cytoskeletal function. In PROJECT B, a major thrust is the expression of the MP Acetyl-LDL receptor with emphasis on the regulatory role of MP activation and differentiation. This project will isolate, purify, and characterize the Ac-LDL receptor of rabbit granuloma macrophages, including its complete primary amino acid sequence. Studies will examine the relative contributions of receptor and non-receptor mediated pathways (pino-phagocytosis) for Lp uptake and metabolism (LDL, Ac-LDL, beta-VLDL) by granuloma macrophages from normal and WHHL rabbits, and the influence of induced activation (gamma-IFN, LPS) on MP Lp receptor expression and function. PROJECT C, focuses on the biology of MP recruitment to the arterial intima. A major emphasis is to determine the structural and functional homology of the 12Kd monocyte chemoattractant (SMC-CF) secreted by arterial SMC and the chemoattractant isolated from lesion-prone areas of the pig aorta (SACF). Studies will compare these two chemoattractants immunochemically, and in terms of receptor expression, and will characterize the biologic functions of SMC-CF both in vitro and in vivo. In vivo studies utilize two established models, namely the Alzet osmotic pump to deliver SMC-CF to the pig aorta, and the Florey rabbit ear chamber. PROJECT D employs glycoprotein processing inhibitors to probe the roles of N linked oligosaccharides in cultured SMC and normal, internalization- defective and receptor-negative FH fibroblasts on LDL receptor synthesis, processing, recycling and LDL metabolism in terms of lysosomal targeting and activities. All 4 projects depend upon CORE units in cell culture, biochemistry, pathology and administration. Quality is monitored by internal and external advisory committees.
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