TAT-Mediated Neurogenin 3 Protein Transduction Stimulates Pancreatic Endocrine Differentiation In Vitro

  1. Juan Domínguez-Bendala1,
  2. Dagmar Klein1,
  3. Melina Ribeiro1,
  4. Camillo Ricordi1,
  5. Luca Inverardi1,
  6. Ricardo Pastori1 and
  7. Helena Edlund12
  1. 1Diabetes Research Institute, University of Miami School of Medicine, Miami, Florida
  2. 2Umeå Center for Molecular Medicine, Umeå University, Umeå, Sweden
  1. Address correspondence and reprint requests to Helena Edlund, Diabetes Research Institute, University of Miami School of Medicine, 1450 NW 10th Ave., Miami, FL 33136. E-mail: helena.edlund{at}med.miami.edu or helena.edlund{at}ucmm.umu.se

Abstract

Stem cell technologies hold great potential for the treatment of type 1 diabetes, provided that functional transplantable β-cells can be selectively generated in an efficient manner. Such a process should recapitulate, at least to a certain extent, the embryonic development of β-cells in vitro. However, progress at identifying the transcription factors involved in β-cell development has not been accompanied by a parallel success at unraveling the pattern of their instructive extracellular signals. Here we present proof of principle of a novel approach to circumvent this problem, based on the use of the HIV/TAT protein transduction domain. Neurogenin 3 (ngn3), a factor whose expression is essential for pancreatic endocrine differentiation, was fused to the TAT domain. Administration of TAT/ngn3 to cultured pancreatic explants results in efficient uptake, nuclear translocation, and stimulation of downstream reporter and endogenous genes. Consistent with the predicted activity of the protein, e9.5 and e13.5 mouse pancreatic explants cultured in the presence of TAT/ngn3 show an increased level of endocrine differentiation compared with control samples. Our results raise the possibility of sequentially specifying stem/progenitor cells toward the β-cell lineage, by using the appropriate sequence and combination of TAT-fused transcription factors.

Footnotes

  • Additional information for this article can be found in an online appendix at http://diabetes.diabetesjournals.org.

    • Accepted November 30, 2004.
    • Received August 26, 2004.
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