Genetic engineering of kidney allografts by ex vivo perfusion delivery of adeno-associated viral vectors

Abstract Despite advances in many domains, the field of solid organ transplantation remains limited by two distinct but connected problems: (1) a critical shortage of donor organs and (2) suboptimal graft longevity due to chronic alloimmune-mediated injury. For patients with end-stage renal disease, these limitations are readily apparent, with over 90,000 individuals in the United States awaiting kidney transplantation. This severe shortfall of donor kidneys is compounded by the suboptimal longevity of transplanted allografts, with a median kidney graft survival of only 8-12 years despite advances in immunosuppression. These significant limitations indicate a clear unmet need to develop novel approaches to improve the function of donor kidneys and enhance graft longevity. The treatment of donor organs with gene therapies has long been recognized as a promising strategy to enhance graft function and diminish graft immunogenicity, but until recently there have not been feasible approaches for gene delivery in an organ-specific manner. Over the last decade, the clinical development of ex vivo organ perfusion systems has created an ideal platform for selectively delivering gene therapies directly to donor allografts. Advancing this approach toward clinical use requires testing in a non-human primate transplant model using clinically relevant immunosuppression regimens. For this proposal, we have assembled a team of investigators with expertise in ex vivo organ perfusion, the use of adeno-associated viral (AAV) vectors for gene therapy, immune management, and kidney transplantation. We have 3 specific aims: 1) Optimize ex vivo machine perfusion approaches for delivery of gene therapies to kidney grafts in an auto-transplant model, 2) Determine the impact of the alloimmune response on transgene expression in kidney allografts, and 3) Evolve novel AAV vectors with tropism for human kidney grafts. Successful completion of this project will demonstrate the use of genetic engineering approaches to achieve durable transgene expression in kidney grafts. This approach has the potential to establish a new paradigm of genetically augmented solid organ allografts and transform approaches in solid organ transplantation.