Stimulation of lipolysis enhances the rate of cholesterol efflux to HDL in adipocytes |
| |
Authors: | Philip B Verghese Estela L Arrese Jose L Soulages |
| |
Institution: | (1) Department of Biochemistry and Molecular Biology, Oklahoma State University, 147 Noble Research Center, Stillwater, OK 74078, USA |
| |
Abstract: | Adipose tissue constitutes a major location for cholesterol storage and, as such, it may play a role in the regulation of
circulating cholesterol levels. A possible metabolic link between the lipolytic activity of adipocytes and their ability to
release cholesterol to reconstituted human high density lipoprotein, HDL, was investigated in 3T3-L1 adipocytes. In the presence
of HDL, composed of human apoA-I and phosphatidylcholine, adipocytes release cholesterol in a lipoprotein-dose and time dependent
fashion. β-adrenergic activation of the lipolysis promotes a 22% increase in the extent of cholesterol efflux to reconstituted
discoidal HDL particles. Activation of lipolysis promotes a rapid decrease in the cholesterol content of the plasma membrane
and a concomitant increase in lipid droplet cholesterol. This change is independent of the presence of HDL. Activation of
the lipolysis does not affect the levels of ABCA1 and SR-BI. Therefore, the enhancement of cholesterol efflux is not due to
the level of plasma membrane cholesterol, or to the levels of the cholesterol transporters ABCA1 and scavenger receptor SR-BI.
Brefeldin A did not affect the rate of cholesterol efflux under basal lipolytic conditions, but it abolished the lipolysis-dependent
enhancement of cholesterol efflux to HDL. This study suggests that activation of lipolysis is accompanied by an increase in
BFA-sensitive vesicular transport that in turn enhances cholesterol efflux to HDL. The study supports a metabolic link between
the lipolytic activity of adipocytes and the rate of cellular cholesterol efflux to HDL. |
| |
Keywords: | Cholesterol Adipocytes ABCA1 Apolipoprotein A1 High density lipoprotein Brefeldin A |
本文献已被 PubMed SpringerLink 等数据库收录! |
|