Expression of lipid droplet proteins in macrophages

CHED 842

Michelle L. Hobbs, shelly.hobbs@otterbein.edu, Department of Life/Earth Sciences and the Department of Chemistry and Biochemistry, Otterbein College, Westerville, OH 43081, Tracy M. Ander, ta282005@ohio.edu, College of Medicine, Ohio University, Athens, OH 45701, and John T. Tansey, JTansey@otterbein.edu, Department of Chemistry and Biochemistry, Otterbein College, Westerville, OH 43081.
This work seeks to elucidate the molecular mechanisms underlying cholesterol storage in cells central to atherosclerosis. Human macrophages express the lipid droplet proteins adipophilin and PAT-1. It has been hypothesized that these proteins and their related family members are involved in the cholesterol storage in foam cells, a central component in the progression of atherosclerosis. Primary cultures of human macrophages were treated at different stages of differentiation with lipid emulsions enriched in LDL to induce cholesterol storage. Cholesterol and protein assays were performed to assay lipid accumulation. Western blots were performed and revealed the increased presence of PAT-1 and Adipophilin upon incubation with LDL. Perilipin A, another lipid droplet protein, was not found. These results show that both PAT-1 and Adipophilin are major proteins involved in cholesterol storage in human macrophages.