Bipartite Adenoviral Vector Encoding hHGF and hIL-1Ra for Improved Human Islet Transplantation

Abstract

Purpose Ex vivo gene therapy can improve the outcome of islet transplantation for treating type I diabetes. Hepatocyte growth factor (HGF) increases β-cell proliferation and promotes revascularization of islets, while interleukin-1 receptor antagonist (hIL-1Ra) inhibits islet cell apoptosis. Methods We constructed Adv-hHGF-hIL-1Ra by cloning hHGF and hIL-1Ra coding sequences and polyA signal under separate CMV promoters in Adenoquick plasmid. Results There was dose and time dependent expression of these genes after transduction of Adv-hHGF-hIL-1Ra into human islets. Compared to un-transduced islets, hHGF and hIL-1Ra gene expression at protein levels was more than 60 and 40 times higher at 1000 MOI, respectively. Transduced islets were viable after incubation with the cocktail of TNF-α, IL-1β and IFN-γ, as evidenced by insulin release in response to glucose concentration. Co-expression of hHGF and hIL-1Ra led to significant decrease in caspase-3 induced by the cytokines. Compared to un-transduced islets, transduction of islets with Adv-hHGF-hIL-1Ra at 1000 MOI prior to transplantation under the kidney capsules of streptozotocin-induced-diabetic NOD-SCID mice reduced blood glucose levels, and increased serum insulin and c-peptide levels. Conclusions Transduction of islets with Adv-hHGF-hIL-1Ra efficiently expresses both growth factor and antiapoptotic genes, decreases caspase-3 and improves the outcome of islet transplantation.

Gene Therapy and Stem Cell Therapy to Improve the Outcome of Human Islet Transplantation

“…Porcine islets are widely reported as a competent alternative for xenogeneic islet transplantation with the assistance of biological and biomaterial approaches to prevent enhanced immune destruction of the xenografts [7,8]. For in vitro transdifferentiation strategy, several groups have reported successful generation of insulin-producing β-cells and islet-like structures from both ES cells.…”

“…Gene transfer of angiogenesis factors such as VEGF and hepatocyte growth factor (HGF) can be an effective strategy to fulfill this purpose and has been widely reported by us and other groups [7][8][9]. VEGF is a popular angiogenic factor, but its effect is so potent that caution should be exercised to avoid aberrant angiogenesis [10].…”

“…We and others have demonstrated adenoviral vector-based gene therapy to be effective in promoting the revascularization and engraftment of human islets posttransplantation [12,15]. For example, growth factor gene expression can significantly improve the islet revascularization after transplantation [4,8,12], while anti-apoptotic protein expression can increase the resistance of islet grafts to multiple posttransplantation challenges in human islets [5,6,15]. The recent success in constructing bipartite viral vectors which can simultaneously promote revascularization and increase the resistance of transplanted islets may highlight the promising future of gene therapy [4,8].…”

“…For example, growth factor gene expression can significantly improve the islet revascularization after transplantation [4,8,12], while anti-apoptotic protein expression can increase the resistance of islet grafts to multiple posttransplantation challenges in human islets [5,6,15]. The recent success in constructing bipartite viral vectors which can simultaneously promote revascularization and increase the resistance of transplanted islets may highlight the promising future of gene therapy [4,8]. However, because of the cluster-like property of islet, multiplicity of infection (MOI) of higher than 500 is usually required to achieve optimal transduction efficiency as suggested from many reports [4,6,8,16].…”

“…The recent success in constructing bipartite viral vectors which can simultaneously promote revascularization and increase the resistance of transplanted islets may highlight the promising future of gene therapy [4,8]. However, because of the cluster-like property of islet, multiplicity of infection (MOI) of higher than 500 is usually required to achieve optimal transduction efficiency as suggested from many reports [4,6,8,16]. Therefore, despite its effectiveness, the clinical application of gene therapy is still hindered by the high risk of immunogenicity of viral vectors.…”