Gene expression and silencing for improved islet transplantation.
Islet transplantation has great potential as an effective means of treating type 1 diabetes. However, its successful application greatly depends on the rapid revascularization of islets and prevention from their apoptotic cell death. We co-expressed human vascular endothelial growth factor (hVEGF) and human interleukin-1 receptor antagonist (hIL-1Ra) after transduction of human islets with Adv-hVEGF-hIL-1Ra. Since hepatocyte growth factor (HGF) increases beta-cell proliferation and promotes revascularization of islets, we also constructed Adv-hHGF-hIL-1Ra. There was dose and time dependent expression of hVEGF and hIL-1Ra or hHGF and hIL-1Ra by islets, which led to decrease in caspase-3 activity and apoptosis induced by a cocktail of TNF-alpha, IL-1beta and IFN-gamma. Compared to non-treated islets, transduction of islets with these bipartite Adv vectors prior to transplantation under the kidney capsules of diabetic NOD-SCID mice reduced the blood glucose levels, and increased serum insulin and c-peptide levels. Immunohistochemical staining of the islet bearing kidney sections was positive for human insulin, growth factor (hVEGF or hHGF) and von Willebrand factor. Transduction with Adv-caspase-3-shRNA also prevented islets from cytokine induced apoptosis and improved islet transplantation. In conclusion, bipartite Adv vector efficiently co-expressed both growth factor and antiapoptotic genes or shRNA targeting pro-apoptotic genes, decreases apoptosis and improves the outcome of islet transplantation.
Department of Pharmaceutical Sciences, University of Tennessee Health Science Center, Memphis, TN 38103, USA. rmahato@utmem.edu
Ram I
RI
Mahato
D000818:Animals; D017209:Apoptosis / Q000502:physiology; D051017:Apoptosis Regulatory Proteins / Q000502:physiology; D053148:Caspase 3 / Q000235:genetics; D015870:Gene Expression / Q000502:physiology*; D020868:Gene Silencing / Q000502:physiology*; D006084:Graft Rejection / Q000235:genetics / Q000517:prevention & control; D006801:Humans; D050417:Insulin-Secreting Cells / Q000378:metabolism; D007515:Islets of Langerhans / Q000378:metabolism; D016381:Islets of Langerhans Transplantation / Q000502:physiology*; D051379:Mice; D018919:Neovascularization, Physiologic / Q000502:physiology; D052247:Nitric Oxide Synthase Type II / Q000235:genetics
D051017:Apoptosis Regulatory Proteins; D052247:Nitric Oxide Synthase Type II; D053148:Caspase 3