Scavenger receptor BI facilitates hepatic very low density lipoprotein production in mice.
J Lipid Res
; 51(3): 544-53, 2010 Mar.
Article
en En
| MEDLINE
| ID: mdl-19723664
ABSTRACT
Scavenger receptor BI (SR-BI) is a selective uptake receptor for HDL cholesterol but is also involved in the catabolism of apolipoprotein (apo)B-containing lipoproteins. However, plasma levels of apoB-containing lipoproteins increase following hepatic SR-BI overexpression, suggesting that SR-BI not solely mediates their catabolism. We therefore tested the hypothesis that hepatic SR-BI impacts on VLDL production. On day 7 following adenovirus (Ad)-mediated overexpression of SR-BI, VLDL-triglyceride and VLDL-apoB production rates were significantly increased (P < 0.001), whereas VLDL production was significantly lower in SR-BI knockout mice compared with controls (P < 0.05). In mice injected with AdSR-BI, hepatic cholesterol content increased (P < 0.001), microsomal triglyceride transfer protein activity was higher (P < 0.01) and expression of sterol-regulatory element binding protein (SREBP)2 and its target genes was decreased (P < 0.01). Conversely, in SR-BI knockout mice, microsomal triglyceride transfer protein activity was lower and expression of SREBP2 target genes was increased (P < 0.01). Finally, we demonstrate in vitro in isolated primary hepatocytes as well as in vivo that cholesterol derived from HDL and taken up via SR-BI into the liver can be resecreted within VLDL. These data indicate that hepatic SR-BI expression is linked to VLDL production, and within liver, a metabolic shunt might exist that delivers HDL cholesterol, at least in part, to a pool from which cholesterol is mobilized for VLDL production. These results might have implications for HDL-based therapies against atherosclerotic cardiovascular disease, especially with SR-BI as target.
Texto completo:
1
Colección:
01-internacional
Base de datos:
MEDLINE
Asunto principal:
Receptores Depuradores de Clase B
/
Lipoproteínas VLDL
/
Hígado
Límite:
Animals
/
Humans
Idioma:
En
Revista:
J Lipid Res
Año:
2010
Tipo del documento:
Article
País de afiliación:
Países Bajos