Pancreatic endocrine cells are transduced by adeno-associated virus serotypes 2 and 9 but not 6

Abstract

ABSTRACTAdeno-associated viruses (AAVs) have emerged as powerful tools for delivery of genes to a variety of cell types including pancreatic endocrine cells. Currently, AAV serotype 8 (AAV8) is the main AAV vector employed for infecting pancreatic cells for transgene transfer. We aimed to address whether alternative serotypes (AAV2, AAV6, and AAV9) commonly used for gene transfer can be effective in transducing pancreatic cells efficiently. We also screened the additives heparin and neuraminidase to further understand the interaction between the individual AAV types included in this work and the cells for optimal infection. Murine pancreatic β-cells and α-cells as well as fibroblasts were infected with AAV serotypes 2, 6, and 9 carrying the transgene for enhanced green fluorescent protein (eGFP). AAV2 outperformed AAV9 in transducing pancreatic cells, while AAV6 induced cytotoxicity. Both AAV2 and AAV9 displayed slightly higher tropism for α-cells than for β-cells. Compared to the pancreatic cells, the fraction of GFP-expressing cells at various multiplicities of infection was consistently lower for fibroblasts. Incubation of AAV2 with heparin prior to transduction failed to induce any GFP expression in β-cells, indicating that the primary site used for initial interaction with pancreatic cells are heparan sulfate proteoglycans. Treatment of β-cells with neuraminidase prior to AAV9 infection appeared to improve the number of GFP-positive cells, but the increase was not statistically significant. These findings expand the repertoire of available serotypes for AAV-mediated delivery of transgenes to pancreatic endocrine cells and may contribute to gene therapy strategies for pancreas pathologies.