Depot-specific differences in perilipin mRNA but not protein expression in obesity

Abstract

Background. Perilipin (PLIN) is a lipid droplet-associated protein, which regulates lipolysis in rodent adipocytes by modulating the access of hormone-sensitive lipase to the lipid surface. Little is known regarding the expression and function of PLIN in man. Subcutaneous (s.c.) and omental fat tissue display marked differences in both basal and stimulated lipolysis. Objective and subjects. In order to assess whether this can be caused by differences in PLIN expression, we investigated the expression of PLIN mRNA and protein in s.c. and omental fat tissue samples from 16 obese women (n = 8) and men (n = 8). Methods. For mRNA detection a quantitative real-time PCR was used. Protein was analysed by Western blot. Results. PLIN mRNA was significantly reduced in omental versus s.c. tissue (P = 0.022). In contrast, although PLIN protein levels were highly variable between the two depots when related to the reference protein β-actin, no significant difference in PLIN protein expression was observed between the fat depots (P = 0.61). There were no gender-specific differences in PLIN mRNA or protein. Conclusion. Our results suggest that post-transcriptional mechanisms may influence PLIN protein expression and that PLIN expression per se is probably not a major factor in determining the lipolytic differences between the s.c. and omental fat depots.