Use of a Hybrid Adeno-Associated Viral Vector Transposon System to Deliver the Insulin Gene to Diabetic NOD Mice.

Que T La,Neeta Khandekar,Sharon C Cunningham,Binhai Ren,Ann M Simpson,Ian E Alexander,Grant J Logan,Najah T Nassif,Bronwyn A O’Brien

doi:10.3390/cells9102227

Abstract

Previously, we used a lentiviral vector to deliver furin-cleavable human insulin (INS-FUR) to the livers in several animal models of diabetes using intervallic infusion in full flow occlusion (FFO), with resultant reversal of diabetes, restoration of glucose tolerance and pancreatic transdifferentiation (PT), due to the expression of beta (β)-cell transcription factors (β-TFs). The present study aimed to determine whether we could similarly reverse diabetes in the non-obese diabetic (NOD) mouse using an adeno-associated viral vector (AAV) to deliver INS-FUR ± the β-TF Pdx1 to the livers of diabetic mice. The traditional AAV8, which provides episomal expression, and the hybrid AAV8/piggyBac that results in transgene integration were used. Diabetic mice that received AAV8-INS-FUR became hypoglycaemic with abnormal intraperitoneal glucose tolerance tests (IPGTTs). Expression of β-TFs was not detected in the livers. Reversal of diabetes was not achieved in mice that received AAV8-INS-FUR and AAV8-Pdx1 and IPGTTs were abnormal. Normoglycaemia and glucose tolerance were achieved in mice that received AAV8/piggyBac-INS-FUR/FFO. Definitive evidence of PT was not observed. This is the first in vivo study using the hybrid AAV8/piggyBac system to treat Type 1 diabetes (T1D). However, further development is required before the system can be used for gene therapy of T1D.

Highlights

Type 1 diabetes (T1D) is characterised by the autoimmune destruction of pancreatic beta (β) cells, resulting in a lack of insulin secretion and hyperglycaemia [1]
Whilst treatment options for T1D are numerous, they are all limited in their long-term effectiveness [8] and, as a result, the search for more innovative and efficacious ways to treat/cure
Both insulin gene therapy and the reprogramming of liver cells to a β-cell phenotype have been studied by many groups as potential options [41]

Summary

Introduction

Type 1 diabetes (T1D) is characterised by the autoimmune destruction of pancreatic beta (β) cells, resulting in a lack of insulin secretion and hyperglycaemia [1]. A patient’s blood glucose levels are controlled by multiple daily injections of insulin or by insulin pumps [2] and the development of fast and long-acting insulin analogues has provided more physiological control than older insulins [3] This approach results in susceptibility to severe hypoglycaemia, Cells 2020, 9, 2227; doi:10.3390/cells9102227 www.mdpi.com/journal/cells. Continuous glucose sensors and insulin pumps have led to the development of the artificial pancreas, which can provide better glycaemic control [5] Issues such as the high costs of the systems, scar tissue associated with microneedle insertion and sensor failure limit their current usefulness [6]. The limitations of lack of donors, complications of immunosuppressive therapy and issues such as blood-mediated inflammatory reactions [8] underscore the need for alternative treatment approaches

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Conclusion