Delivery of Bcl-XL or its BH4 domain by protein transduction inhibits apoptosis in human islets

Biochem Biophys Res Commun. 2004 Oct 15;323(2):473-8. doi: 10.1016/j.bbrc.2004.08.116.


Viability of isolated islets is one of the main obstacles limiting islet transplantation success. It has been reported that overexpression of Bcl-2/Bcl-XL proteins enhances islet viability. To avoid potential complications associated with long-term expression of anti-apoptotic proteins, we investigated the possibility of delivering Bcl-XL or its anti-apoptotic domain BH4 to islets by protein transduction. Bcl-XL and BH4 molecules were fused to TAT/PTD, the 11-aa cell penetrating peptide from HIV-1 transactivating protein, generating TAT-Bcl-XL and TAT-BH4, respectively. Transduction efficiency was assessed by laser scanning confocal microscopy of live islets. Biological activity was tested as the ability to protect NIT-1 insulinoma cell line from death induced by staurosporine or serum deprivation. Spontaneous caspase activation in human islets and cytotoxicity caused by IL-1beta were significantly reduced in the presence of TAT-Bcl-XL and TAT-BH4. We conclude that both TAT proteins are biologically active after transduction and could be an asset in the improvement of islet viability.

Publication types

  • Comparative Study
  • Evaluation Study
  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Animals
  • Apoptosis / drug effects
  • Apoptosis / physiology*
  • Cells, Cultured
  • Feasibility Studies
  • Genetic Enhancement / methods
  • Humans
  • Islets of Langerhans / cytology*
  • Islets of Langerhans / drug effects
  • Islets of Langerhans / physiology*
  • Primates
  • Protein Engineering / methods*
  • Protein Structure, Tertiary / genetics
  • Proto-Oncogene Proteins c-bcl-2 / genetics*
  • Proto-Oncogene Proteins c-bcl-2 / metabolism*
  • Recombinant Proteins / metabolism
  • Staurosporine / pharmacology
  • Transduction, Genetic / methods*
  • bcl-X Protein


  • BCL2L1 protein, human
  • Proto-Oncogene Proteins c-bcl-2
  • Recombinant Proteins
  • bcl-X Protein
  • Staurosporine