Pioglitazone stimulates apolipoprotein A-I production without affecting HDL removal in HepG2 cells: involvement of PPAR-alpha.
Arterioscler Thromb Vasc Biol
; 27(11): 2428-34, 2007 Nov.
Article
em En
| MEDLINE
| ID: mdl-17872455
ABSTRACT
OBJECTIVE:
Pioglitazone, an antihyperglycemic drug, increases plasma high-density lipoprotein (HDL)-cholesterol in patients with type 2 diabetes. The mechanisms by which pioglitazone regulate HDL levels are not clear. This study examined the effect of pioglitazone on hepatocyte apolipoprotein AI (apoA-I) and apoA-II production and HDL-protein/cholesterol ester uptake. METHODS ANDRESULTS:
In human hepatoblastoma (HepG2) cells, pioglitazone, dose-dependently (0.5 to 10 micromol/L), increased the de novo synthesis (up to 45%), secretion (up to 44%), and mRNA expression (up to 59%) of apoA-I. Pioglitazone also increased apoA-II de novo synthesis (up to 73%) and mRNA expression (up to 129%). Pioglitazone did not affect the uptake of HDL3-protein or HDL3-cholesterol ester in HepG2 cells. The pioglitazone-induced apoA-I lipoprotein particles increased cholesterol efflux from THP-1 macrophages. The pioglitazone-induced apoA-I secretion or mRNA expression by the HepG2 cells was abrogated with the suppression of PPAR-alpha by small interfering RNA or a specific inhibitor of PPAR-alpha, MK886.CONCLUSIONS:
The data indicate that pioglitazone increases HDL by stimulating the de novo hepatic synthesis of apoA-I without affecting hepatic HDL-protein or HDL-cholesterol removal. We suggest that pioglitazone-mediated hepatic activation of PPAR-alpha may be one of the mechanisms of action of pioglitazone to raise hepatic apoA-I and HDL.
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Base de dados:
MEDLINE
Assunto principal:
Apolipoproteína A-II
/
Apolipoproteína A-I
/
Tiazolidinedionas
/
Hipoglicemiantes
/
Lipoproteínas HDL
Limite:
Humans
Idioma:
En
Ano de publicação:
2007
Tipo de documento:
Article