DsAAV8-mediated gene transfer and Β-cell expression of IL-4 and Β-cell growth factors are capable of reversing early-onset diabetes in NOD mice

Type-I diabetes is a chronic disease mediated by autoimmune destruction of insulin-producing β-cells. Although progress has been made towards improving diabetes-associated pathologies and the quality of life for those living with diabetes, no therapy has been effective at eliminating disease manifestations or reversing disease progression. Here, we examined whether double-stranded adeno-associated virus serotype 8 (dsAAV8)-mediated gene delivery to endogenous Β-cells of interleukin (IL)-4 in combination with Β-cell growth factors can reverse early-onset diabetes in NOD mice. Our results demonstrate that a single treatment with dsAAV8 vectors expressing IL-4 in combination with glucagon-like peptide-1 or hepatocyte growth factor/NK1 under the regulation of the insulin promoter enhanced Β-cell proliferation and survival in vivo, significantly delaying diabetes progression in NOD mice, and reversing disease in 10% of treated NOD mice. These results demonstrate the ability to reverse hyperglycemia in NOD mice with established diabetes by in vivo gene transfer to Β-cells of immunomodulatory factors and β-cell growth factors.