Induced expression of adipophilin mRNA in human macrophages stimulated with oxidized low-density lipoprotein and in atherosclerotic lesions.

Oxidized low-density lipoprotein (OxLDL) plays a critical role in foam cell formation and atherosclerogenesis. A cDNA encoding adipophilin was identified in cultured human macrophages stimulated with OxLDL using mRNA differential display. Adipophilin is a 50 kDa protein known to be a specific marker for adipocyte cell differentiation and lipid accumulation in a variety of cells. The time-dependent induction of adipophilin mRNA in macrophages was specific to OxLDL but not native LDL, and not to various cytokines and serum. In human atherosclerotic lesions, adipophilin mRNA expression was localized in a subset of lipid-rich macrophages. These data suggest that adipophilin-expressing macrophages may represent foam cells and this gene expression is likely to be associated with the lipid accumulation in foam cells of the atherosclerotic lesions.