Sterol regulatory element-binding protein 1 mediates liver X receptor-beta-induced increases in insulin secretion and insulin messenger ribonucleic acid levels.
Endocrinology
; 147(8): 3898-905, 2006 Aug.
Article
em En
| MEDLINE
| ID: mdl-16644917
ABSTRACT
Liver X receptors (LXRalpha and LXRbeta) regulate glucose and lipid metabolism. Pancreatic beta-cells and INS-1E insulinoma cells express only the LXRbeta isoform. Activation of LXRbeta with the synthetic agonist T0901317 increased glucose-induced insulin secretion and insulin content, whereas deletion of the receptor in LXRbeta knockout mice severely blunted insulin secretion. Analysis of gene expression in LXR agonist-treated INS-1E cells and islets from LXRbeta-deficient mice revealed that LXRbeta positively regulated expression of ATP-binding cassette transporter A1 (ABCA1), sterol regulatory element-binding protein 1 (SREBP-1), insulin, PDX-1, glucokinase, and glucose transporter 2 (Glut2). Down-regulation of SREBP-1 expression with the specific small interfering RNA blocked basal and LXRbeta-induced expression of pancreatic duodenal homeobox 1 (PDX-1), insulin, and Glut2 genes. SREBP-1 small interfering RNA also prevented an increase in insulin secretion and insulin content induced by T0901317. Moreover, 5-(tetradecyloxy)-2-furoic acid, an inhibitor of the SREBP-1 target gene acetyl-coenzyme A carboxylase, blocked T0901317-induced stimulation of insulin secretion. In conclusion, activation of LXRbeta in pancreatic beta-cells increases insulin secretion and insulin mRNA expression via SREBP-1-regulated pathway. These data support the role of LXRbeta, SREBP-1, and cataplerosis/anaplerosis pathways in the control of insulin secretion in pancreatic beta-cells.
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Coleções:
01-internacional
Base de dados:
MEDLINE
Assunto principal:
Receptores Citoplasmáticos e Nucleares
/
Proteínas de Ligação a DNA
/
Proteína de Ligação a Elemento Regulador de Esterol 1
/
Insulina
Limite:
Animals
Idioma:
En
Revista:
Endocrinology
Ano de publicação:
2006
Tipo de documento:
Article