Pathological Significance of Macrophage Scavenger Receptors

点击翻译按钮获取中文摘要

1. Anti-human monoclonal antibodies for macrophage scavenger receptors (MSR), as well as polyclonal antibodies for synthetic peptides of MSR, were generated in our laboratory. Using these antibodies, our immunohistochemical and immunoelectron microscopic studies demonstrated that MSR was distributed on the cell membranes of macrophages ubiquitously distributed in various organs and tissues of humans. Immunohistochemical and immunoelectron microscopic investigation with anti-bovine or anti-murine MSR monoclonal antibodies revealed similar distribution and subcellar localization of MSR in bovine and murine tissues.2. Our studies demonstrated in humans, bovines, and mice that MSR can bind to modified low density lipoproteins (LDL) such as acetylated LDL (acLDL) or oxidized LDL (oxLDL) and to advanced glycation end products (AGE). MSR-deficient mice revealed marked reductions in the uptake of acLDL, oxLDL, and AGE.3. In atheroselerotic lesions of human aorta, macrophage-derived foam cells showed the expression of MSR and intracellular accumulation of oxLDL and AGE.In apo-E/MSR double knockout mice and diet-induced LDL receptor/MSR double knockout mice, the lesion size of atheroselerosis was markedly reduced in the aorta, compared with apo-E or diet-induced LDL receptor-single knockout mice, indicating that MSR is deeply implicated in atherognesis.4. Compared with the wild-type mice, the hepatic granuloma formation induced by intravenous injection of heat-killed Corynebacterium parvum (C.parvum) was delayed and the uptake of C.parvum by Kupffer cells was markedly impaire in MSR-deficient mice, particularly in the early stage. These results indicate that MSR is involved in the defense mechanisms against exogenously invading bacteria.