title: Delivery of Bcl-XL or its BH4 domain by protein transduction inhibits apoptosis in human islets.
abstract: 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.
authors.affiliation: Diabetes Research Institute, University of Miami School of Medicine, Miami, FL, USA.
authors.forename: Dagmar
authors.initials: D
authors.lastname: Klein
authors.forename: Melina M
authors.initials: MM
authors.lastname: Ribeiro
authors.forename: Valeska
authors.initials: V
authors.lastname: Mendoza
authors.forename: Sundararajan
authors.initials: S
authors.lastname: Jayaraman
authors.forename: Norma S
authors.initials: NS
authors.lastname: Kenyon
authors.forename: Antonello
authors.initials: A
authors.lastname: Pileggi
authors.forename: R Damaris
authors.initials: RD
authors.lastname: Molano
authors.forename: Luca
authors.initials: L
authors.lastname: Inverardi
authors.forename: Camillo
authors.initials: C
authors.lastname: Ricordi
authors.forename: Ricardo L
authors.initials: RL
authors.lastname: Pastori
mesh_terms: D000818:Animals; D017209:Apoptosis / Q000187:drug effects / Q000502:physiology*; D002478:Cells, Cultured; D005240:Feasibility Studies; D024861:Genetic Enhancement / Q000379:methods; D006801:Humans; D007515:Islets of Langerhans / Q000166:cytology* / Q000187:drug effects / Q000502:physiology*; D011323:Primates; D015202:Protein Engineering / Q000379:methods*; D017434:Protein Structure, Tertiary / Q000235:genetics; D019253:Proto-Oncogene Proteins c-bcl-2 / Q000235:genetics* / Q000378:metabolism*; D011994:Recombinant Proteins / Q000378:metabolism; D019311:Staurosporine / Q000494:pharmacology; D014161:Transduction, Genetic / Q000379:methods*; D051020:bcl-X Protein
chemical_list: C494811:BCL2L1 protein, human; D019253:Proto-Oncogene Proteins c-bcl-2; D011994:Recombinant Proteins; D051020:bcl-X Protein; D019311:Staurosporine