Protection and restoration of a functional β-cell mass are fundamental strategies for prevention and treatment of diabetes. Consequently, knowledge of signals that determine the functional β-cell mass is of immense clinical relevance. Transforming growth factor β (TGFβ) superfamily signaling pathways play a critical role in development and tissue specification. Nevertheless, the role of these pathways in adult β-cell homeostasis is not well defined. Here, we ablated TGFβ receptor I and II genes in mice undergoing two surgical β-cell replication models (partial pancreatectomy or partial duct ligation), representing two triggers for β-cell proliferation, increased β-cell workload, and local inflammation, respectively. Our data suggest that TGFβ receptor signaling is necessary for baseline β-cell proliferation. By either provision of excess glucose or treatment with exogenous insulin, we further demonstrated that inflammation and increased β-cell work-load are both stimulants for β-cell proliferation but are TGFβ receptor signaling- dependent and independent, respectively. Collectively, by using a pancreas-specific TGFβ receptor–deleted mouse model, we have identified two distinct pathways that regulate adult β-cell proliferation. Our study thus provides important information for understanding β-cell proliferation during normal growth and in pancreatic diseases.
- Received October 16, 2012.
- Accepted October 30, 2012.
- © 2013 by the American Diabetes Association.
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