Correlation of gene expression changes and cell signalling pathways in insulin-expressing mouse liver cells transduced with an integrating adeno-associated viral vector

Type 1 Diabetes (T1D) is a chronic, metabolic disorder for which current treatments are unable to prevent the onset of complications. Previously, we used an adeno-associated viral vector (AAV8) to deliver furin-cleavable human insulin (INS-FUR) to the livers of diabetic non-obese diabetic (NOD) mice to reverse T1D. Use of the traditional AAV8-INS-FUR vector was not able to bring about normoglycaemia, however this vector, coupled with a transposon system, in the AAV8/piggyBac-INS-FUR vector, was able to do so. The aim of this study was to investigate the transcriptomic profiles of diabetic, AAV8-INS-FUR transduced, and AAV8/piggyBac-INS-FUR transduced livers and compared these to normal liver to identify genetic differences resulting from delivery of the AAV8/piggyBac-INS-FUR vector which produced normoglycaemia. Differen-tial gene expression was determined by RNA-Seq analysis and the differentially expressed genes from each treatment were mapped on to cellular pathways to determine cellular signalling and downstream effects of the treatments. We observed distinct differences between the piggyBac transduced and diabetic models, particularly in terms of metabolic function and the upregulation of key pancreatic markers in the liver of piggyBac transduced animals. The success of the piggyBac vector in achieving normoglycemia through stable transduction was evident, however further advancements are necessary to achieve complete pancreatic transdifferentiation of liver cells. Overall design: RNA was extraction from 1) non-diabetic untreated liver 2) diabetic,non-treated liver, 3) AAV8-INS-FUR transduced liver 4) AAV8/piggyBac transduced liver