Platelet-Targeted Gene Therapy Of Hemophilia A Using Hematopoietic Stem Cells Derived From Genome-Edited Induced Pluripotent Stem Cells

Hemophilia A (HA), an X-linked recessive hereditary bleeding disorder, is caused by mutations in the F8 gene, which encodes the coagulation factor VIII (FVIII). Replacement therapy is the mainstay in clinic, but it can also cause inhibitory antibodies and is therefore restricted in wide use. Effective therapy of HA with inhibitors needs to be considered as a matter of priority. Evidence has been obtained that functional FVIII can be ectopically expressed and stored in platelets after transplantation of F8 gene modified-hematopoietic stem cells (HSCs), and the stored-FVIII can be released during the activation of platelets to exert therapeutic effect on HA with inhibitors. This unique strategy, however, requires enough sources of HSCs and a safe and effective way of HSCs modification. Induced pluripotent stem cells (iPSCs) are capable of self-renewing, large-scale expansion and differentiating into almost all types of cells and tissues. These features make iPSCs a promising path in the field of regenerative medicine and cell therapy. The recently developed techniques of genome editing, especially the CRISPR/Cas9 system, provide a powerful tool for gene therapy, owing to significantly reduced risk of insertional mutagenesis as compared to the random integration in retroviral-mediated gene therapy. Hence, we seek to explore the possibility of utilizing iPSCs and CRISPR/Cas9 in the platelet-targeted gene therapy of HA.