Phenotypic correction of murine hemophilia A using an iPS cell-based therapy

Abstract

Hemophilia A is caused by mutations within the Factor VIII (FVIII) gene that lead to depleted protein production and inefficient blood clotting. Several attempts at gene therapy have failed for various reasons-including immune rejection. The recent generation of induced pluripotent stem (iPS) cells from somatic cells by the ectopic expression of 3 transcription factors, Oct4, Sox2, and Klf4, provides a means of circumventing the immune rejection barrier. To date, iPS cells appear to be indistinguishable from ES cells and thus provide tremendous therapeutic potential. Here we prepared murine iPS cells from tail-tip fibroblasts and differentiated them to both endothelial cells and endothelial progenitor cells by using the embryoid body differentiation method. These iPS cells express major ES cell markers such as Oct4, Nanog, SSEA-1, alkaline phosphatase, and SALL4. Endothelial/endothelial progenitor cells derived from iPS cells expressed cell-specific markers such as CD31, CD34, and Flk1 and secreted FVIII protein. These iPS-derived cells were injected directly into the liver of irradiated hemophilia A mice. At various times after transplantation (7-90 days) hemophilia A mice and their control mice counterparts were challenged by a tail-clip bleeding assay. Nontransplanted hemophilia A mice died within a few hours, whereas transplanted mice survived for more than 3 months. Plasma FVIII levels increased in transplanted hemophilia A mice during this period to 8% to 12% of wild type and corrected the hemophilia A phenotype. Our studies provide additional evidence that iPS cell therapy may be able to treat human monogenetic disorders in the future.endothelial cell precursors ͉ Factor VIII ͉ Oct4 ͉ Sox2 ͉ Klf4

A novel xeno-free and feeder-cell-free system for human pluripotent stem cell culture

“…Human induced pluripotent stem cells (hiPSCs) not only have the capacity to differentiate into the cell lineages of the three germ layers, but also allow for the generation of disease-specific and patient-specific hiPSCs. Many gene-deficient diseasespecific iPSCs have been derived (Park et al, 2008;Lee et al, 2009;Ghodsizadeh et al, 2010;Somers et al, 2010), and disease phenotypes can be greatly ameliorated by transplantation of gene-corrected iPSC-differentiated cells (Hanna et al, 2007;Wernig et al, 2008;Xu et al, 2009), providing proof of concept for future iPSC-based therapies (Li and Zhou, 2010;Zhang and Gao, 2010). Patient-specific iPSCs should allow the production of genetically-identical cell populations free of immunological rejection when applied in future cell transplantation therapies.…”

Replacing bad (F)actors: hemophilia

“…For example, Xu et al generated iPSCs from tail tip fibroblasts of healthy mice, differentiated the cells toward an endothelial phenotype (CD31 ϩ CD34 ϩ Flk-1 ϩ ), and then transplanted them directly into the livers of irradiated hemophilia A mice. 21 After transplantation, recipient mice displayed plasma FVIII activity levels in the range of 8%-12% and survived a bleeding challenge via tail transection assay. Ohmori et al also investigated the therapeutic potential of murine iPSCs, although SIV-based lentivector gene transfer of a BDD h-FVIII transgene was used to enhance, if not provide the sole source of, FVIII.…”

iPSCs and small molecules: a reciprocal effort towards better approaches for drug discovery

“…Neurospheres produced by iPSCs have been transplanted into the brain of a spinal-cord injury mouse model, and functional recovery was confirmed with accompanying re-myelination and axonal regrowth [13] . Transplantation of factor VIII (FVIII)-producing endothelial cells derived from iPSCs has been reported to rescue mice carrying hemophilia A (caused by a mutation in FVIII) from a deathinducing bleeding assay [14] . In addition, iPSCs have also been differentiated into functional cardiac myocytes [15] , and humaniPSC-derived cardiac myocytes have been shown to improve the cardiac contractile function in the experimentally injured rodent heart [16,17] .…”