NG.I.4 - AAV-mediated gene therapy in central nervous system of dystrophin-Dp71 deficient mouse

Abstract

The understanding of dystrophin-dependent physiological mechanisms responsible for DMD led to the development of innovative tools for gene-therapy strategies based on splice-switching correction or replacement strategies. However, much less is known on their potency to alleviate the retina and brain deficiencies associated with DMD. Molecular tools specifically targeting the Dp71 protein responsible for altered glial physiology and intellectual disability have long been lacking. In both brain and retina Dp71 is mainly expressed in macroglial cells, which poses the challenge to engineer specific properties for viral vectors to selectively target these cells, penetrate CNS barriers and deeply spread in neural tissues. Our progresses in developing new generations of AAV vectors had overcome such limitations. In retina, the loss of Dp71 in Müller Glial cells is associated with altered blood-retinal barrier (BRB) permeability. We have shown that an AAV variant, ShH10, transduces Müller cells in the Dp71-null mouse retina efficiently and specifically. We used ShH10 to restore Dp71 expression in Müller cells of Dp71-null mice and obtained strong and specific expression of exogenous Dp71. This was associated with relocalization of Dp71, restoration of all cell and protein interactions and functional rescue of BRB and retina homeostasis, thus preventing retina from oedema. This study is the basis for development of new therapeutic strategies in dealing with diseases with BRB breakdown and macular oedema such as diabetic retinopathy. A similar approach aimed at rescuing brain Dp71 will determine the potential of such tools to alleviate brain and cognitive dysfunctions in this model.