Anti-inflammatory action of exendin-4 in human islets is enhanced by phosphodiesterase inhibitors: potential therapeutic benefits in diabetic patients.
Diabetologia
; 53(11): 2357-68, 2010 Nov.
Article
em En
| MEDLINE
| ID: mdl-20635178
ABSTRACT
AIMS/HYPOTHESIS:
Exendin-4, a glucagon-like peptide-1 (GLP-1) analogue, is reported to have modest anti-inflammatory effects in addition to that of improving beta cell survival. We therefore sought to determine whether exendin-4 decreases expression of the gene encoding chemokine (C-X-C motif) ligand (CXCL)10, which plays a role in initiating insulitis in type 1 diabetes.METHODS:
The expression of CXCL10 in human islets was determined at the mRNA level by real-time RT-PCR analysis and at the protein level by western blotting. The level of CXCL10 in culture medium was measured by ELISA. Pathway-specific gene expression profiling was carried out to determine the expression of a panel of genes encoding chemokines and cytokines in human islets exposed to cytokines.RESULTS:
IFN-γ induced expression of CXCL10 through activation of signal transducer and activator of transcription-1 (STAT-1). A combination of cytokines (IL-1ß, TNF-α and IFN-γ) showed strong synergy in the induction of numerous chemokines and cytokines through nuclear factor kappa B and STAT-1. Exendin-4 suppressed basal expression of several inflammatory mediators. In combination with phosphodiesterase inhibitors, exendin-4 also decreased IFN-γ-induced CXCL10 expression in human islets and in MIN6 cells (a mouse beta cell line), and its secretion into the culture medium. Exendin-4 action was mimicked by forskolin, an activator of adenylyl cyclase, and by dibutyryl cyclic AMP. Protein kinase A was not involved in mediating exendin-4 action on CXCL10. The mechanism of exendin-4's anti-inflammatory action involved decreases in STAT-1 levels. CONCLUSIONS/INTERPRETATION:
These findings suggest that the GLP-1-cyclic AMP pathway decreases islet inflammation in addition to its known effects on beta cell survival.
Texto completo:
1
Coleções:
01-internacional
Base de dados:
MEDLINE
Assunto principal:
Peptídeos
/
Inibidores de Fosfodiesterase
/
Peçonhas
/
Ilhotas Pancreáticas
/
Diabetes Mellitus
/
Anti-Inflamatórios
Limite:
Humans
Idioma:
En
Revista:
Diabetologia
Ano de publicação:
2010
Tipo de documento:
Article
País de afiliação:
Estados Unidos