Human and rodent pancreatic beta-cells express IL-4 receptors and IL-4 protects against beta-cell apoptosis by activation of the PI3K and JAK/STAT pathways.
Biosci Rep
; 30(3): 169-75, 2009 Dec 15.
Article
en En
| MEDLINE
| ID: mdl-19531027
ABSTRACT
Secretion of pro-inflammatory cytokines is associated with loss of pancreatic beta-cell viability and cell death. IL-4 (interleukin-4) has been reported to mediate a protective effect against the loss of pancreatic beta-cells, and IL-4 receptors have been found in rat pancreatic beta-cells at both the RNA and the protein level. The aim of the present study was to investigate IL-4 receptor expression in human islet cells and to examine the signalling pathways by which IL-4 exerts its effects using the rat beta-cell lines, BRIN-BD11 and INS-1E. By means of immunohistochemistry, it was demonstrated that IL-4 receptors are present on human islet cells. Using a flow cytometric method for evaluating cell death, it was confirmed that incubating beta-cells with IL-4 attenuated cell death induced by IL-1beta and interferon-gamma by approx. 65%. This effect was abrogated by the presence of the PI3K (phosphoinositide 3-kinase) inhibitor, wortmannin, suggesting that activation of the PI3K pathway is involved. In support of this, Western blotting revealed that incubation of cells with IL-4 resulted in increased phosphorylation of Akt (also called protein kinase B), a downstream target of PI3K. Increased tyrosine phosphorylation of STAT6 (signal transducer and activator of transcription 6) also occurred in response to IL-4 and a selective JAK3 (Janus kinase 3) inhibitor reduced the cytoprotective response. Both effects were prevented by overexpression of the tyrosine phosphatase, PTP-BL (protein tyrosine phosphatase-BL). We conclude that IL-4 receptors are functionally competent in pancreatic beta-cells and that they signal via PI3K and JAK/STAT pathways. These findings may have implications for future therapeutic strategies for the management of diabetes.
Texto completo:
1
Colección:
01-internacional
Banco de datos:
MEDLINE
Asunto principal:
Transducción de Señal
/
Interleucina-4
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Apoptosis
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Fosfatidilinositol 3-Quinasas
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Receptores de Interleucina-4
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Células Secretoras de Insulina
Límite:
Animals
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Humans
Idioma:
En
Revista:
Biosci Rep
Año:
2009
Tipo del documento:
Article
País de afiliación:
Reino Unido