Cancer Institute A national cancer institute
designated cancer center

Roeland Nusse

Publication Details

  • Wnt signaling regulates pancreatic beta cell proliferation PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA Rulifson, I. C., Karnik, S. K., Heiser, P. W., Ten Berge, D., Chen, H., Gu, X., Taketo, M. M., Nusse, R., Hebrok, M., Kim, S. K. 2007; 104 (15): 6247-6252

    Abstract:

    There is widespread interest in defining factors and mechanisms that stimulate proliferation of pancreatic islet cells. Wnt signaling is an important regulator of organ growth and cell fates, and genes encoding Wnt-signaling factors are expressed in the pancreas. However, it is unclear whether Wnt signaling regulates pancreatic islet proliferation and differentiation. Here we provide evidence that Wnt signaling stimulates islet beta cell proliferation. The addition of purified Wnt3a protein to cultured beta cells or islets promoted expression of Pitx2, a direct target of Wnt signaling, and Cyclin D2, an essential regulator of beta cell cycle progression, and led to increased beta cell proliferation in vitro. Conditional pancreatic beta cell expression of activated beta-catenin, a crucial Wnt signal transduction protein, produced similar phenotypes in vivo, leading to beta cell expansion, increased insulin production and serum levels, and enhanced glucose handling. Conditional beta cell expression of Axin, a potent negative regulator of Wnt signaling, led to reduced Pitx2 and Cyclin D2 expression by beta cells, resulting in reduced neonatal beta cell expansion and mass and impaired glucose tolerance. Thus, Wnt signaling is both necessary and sufficient for islet beta cell proliferation, and our study provides previously unrecognized evidence of a mechanism governing endocrine pancreas growth and function.

    View details for DOI 10.1073/pnas.0701509104

    View details for Web of Science ID 000245737500029

    View details for PubMedID 17404238

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