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Exp Clin Endocrinol Diabetes. 2010 Nov;118(10):692-8. doi: 10.1055/s-0030-1254151. Epub 2010 Jun 8.

Protective effect of hedgehog signaling on cytokine-induced cytotoxicity in pancreatic beta-cells.

Author information

1
Department of Endocrinology and Diabetes, Field of Internal Medicine, Nagoya University Graduate School of Medicine, Nagoya, Japan.

Abstract

BACKGROUND:

Hedgehog (Hh) signaling plays an important role in pancreas development. However, its role in the developed endocrine pancreas remains to be elucidated. To clarify whether Hh signaling participates in beta-cell survival, we investigated the role of Hh signaling in cytokine-induced apoptosis in pancreatic beta-cells.

METHODS:

Insulin-producing INS-1E cells were transfected with Sonic Hh (Shh) expression vector or siRNA against Indian Hh (siIhh). The Hh signal inhibitor cyclopamine were pretreated in INS-1E cells and rat islets. The cells were exposed to 200 U/ml IL-1β and 200 U/ml IFN-γ for 48 h. Apoptosis was estimated by flow cytometory and immunofluorescence staining for cleaved caspase-3. Nitric oxide generation was measured by Griess reaction.

RESULTS:

We found that exposure to proinflammatory cytokines increased Ihh expression in rat islets and INS-1E cells. Overexpression of Shh reduced cytokine-induced apoptosis. By contrast, treatment with cyclopamine increased cytokine-induced apoptosis in INS-1E cells and rat islets. Treatment with the siIhh showed same results in INS-1E cells. Forced expression of Shh suppressed cytokine-induced nuclear factor-κB promoter activity, leading to attenuation of nitric oxide synthase 2 expression and nitric oxide production, while Ihh knockdown enhanced this pathway in INS-1E cells.

CONCLUSION:

Our findings suggest that Hh signaling is implicated in protecting beta-cells from cytokine-induced cytotoxicity.

PMID:
20533175
DOI:
10.1055/s-0030-1254151
[Indexed for MEDLINE]

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