C-reactive protein-mediated low density lipoprotein uptake by macrophages - Implications for atherosclerosis

Background-LDL and C-reactive protein (CRP) are important cardiovascular ri sk factors. Both LDL and CRP deposit in the arterial wall during atherogene sis. Stranded LDL is taken up by macrophages, causing foam cell formation. Because native LDL does not induce foam cell formation, we hypothesized tha t CRP may opsonize native LDL for macrophages. Methods and Results-Monocytes were isolated from human blood and transforme d into macrophages, CRP/LDL uptake was assessed by immunofluorescent labeli ng and the use of confocal laser scanning microscopy, Native LDL coincubate d with CRP was taken up by macrophages by macropinocytosis. Uptake of the C RP/LDL coincubate was mediated by the CRP receptor CD32. Conclusions-We conclude that foam cell formation in human atherogenesis may be caused in part by uptake of CRP-opsonized native LDL.