Expression of lipid droplet proteins in macrophages

CHED 903

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 protein adipophilin (also known as ADRP). It has been hypothesized that this protein and its related family members are involved in cholesterol storage in foam cells, a component of atherosclerotic plaques. Primary cultures of human macrophages were treated at different stages of differentiation with lipid emulsions enriched in either cholesteryl oleate or egg lipid to induce cholesterol storage. Cholesterol and protein assays were performed to assay lipid accumulation. Cholesterol storage was increased 25 % in cells incubated with the egg lipid emulsion. Western blots were performed and revealed increased amounts of ADRP in cells incubated with both types of lipids and the absence of perilipin, another lipid droplet protein. Collectively these data show that ADRP is the major lipid droplet protein involved in cholesterol storage in macrophages.