Thursday, 23 January 2020 | 3:00 pm

Università degli Studi del Piemonte Orientale “A. Avogadro”, Dip. di Scienze della Salute (Dept. of Health Sciences), Novara, ITALIA

Cell and gene therapy for hemophilia A

(Host: F. Pagani)

We generated patient-specific disease-free induced pluripotent stem cells (iPSCs) and differentiated them into functional endothelial cells (ECs) secreting factor VIII (FVIII) for gene and cell therapy approaches to cure hemophilia A (HA). iPSCs were transduced with a lentiviral vector carrying FVIII transgene driven by an endothelial-specific promoter (VEC) and differentiated into bona fide ECs. FVIII-expressing ECs were transplanted, engrafted and proliferated in the liver along sinusoids and in the long term (up to 6 m) showed stable therapeutic FVIII activity (6%), confirming the feasibility of cell-reprogramming strategy in patient- derived cells as an approach for HA gene and cell therapy. This approach was further developed in the Hemacure grant. We were able to genetically correct hemophilic BOECs (blood outgrowth endothelial cells) and transplant them in a device inserted under the skin of hemophilic immunocompromised mice and correct the bleeding phenotype.

We previously demonstrated that FVIII is produced specifically in liver sinusoid endothelial cells (LSECs) and to some degree in myeloid cells, and thus, in the present work, we seek to restrict the expression of FVIII transgene to these cells using cell-specific promoters. With this approach, we aim to limit immune response in a mouse model by lentiviral vector (LV)-mediated gene therapy encoding FVIII. Moreover, we are now developing additional cell specific promoters to induce tolerance and long-term expression for therapeutic purposes. In particular, the naïve FVIII promoter is one of the major promoter elements we are exploring.