Safe and long-term in vivo tolerogenic expression of FVIII by LV targeting hepatic endothelial cells

The proposer has an extensive and well recognized expertise in the field of cell and gene therapy for HA, especially for LV vector design, endothelial targeting, and in vivo preclinical models. The know-how, optimized protocols and the facilities ensure the feasibility of this project. The main goal is to evaluate the eventual cell damage, at steady state and during growth, following endothelial-specific LV-directed gene therapy caused by an unfolded protein response (UPR) and potential endoplasmic reticulum (ER) stress as observed for hepatocyte directed AAV gene therapy in preclinical studies and possibly causing an immune response to the transgene, thus resulting in a decrease in FVIII expression over time. We propose in vivo studies, exploiting a mouse model of both adult and neonatal HA, of endothelial specific LV-FVIII gene therapy and immunological studies aimed at evaluating the safety and stability of endothelial-specific FVIII gene therapy and its involvement in tolerance induction to FVIII. Since the decrease of FVIII transgene in ongoing clinical trials represents an open issue with respect to novel therapeutic approaches in patient’s care, the proposed approach will help in adding data on safety and stability of LV-mediated gene therapy, while leading to new insights to predict the players involved in immune tolerance induction to FVIII in hemophilic patients and contributing to Europe and PNRR commitment on Research and Innovation.