High-level expression of porcine factor VIII from genetically modified bone marrow-derived stem cells.

Abstract

Clinical success for gene therapy of hemophilia A will be judged by achievement of sustained, therapeutic levels of coagulation factor VIII (fVIII). Previous clinical trials have suffered from transient, subtherapeutic expression of human fVIII transgenes. Porcine fVIII contains sequence elements that enable more efficient biosynthesis than human fVIII due to enhanced posttranslational transit through the secretory pathway. In this study, we evaluated ex vivo retroviral gene transfer of a high-expression porcine fVIII transgene into bone marrow-derived stromal and hematopoietic stem/progenitor cells (MSCs and HSCs, respectively) and transplantation into genetically immunocompetent hemophilia A mice. Both MSCs and HSCs demonstrated high-level expression of porcine fVIII in vivo. However, following transplantation of gene-modified MSCs, fVIII activity levels rapidly returned to baseline due to the formation of anti-porcine fVIII-neutralizing antibodies. Alternatively, transplantation of HSCs into myeloablated and nonmyeloablated hemophilia A mice resulted in high-level fVIII expression despite low-level hematopoietic reconstitution by gene-modified cells. FVIII expression was sustained beyond 10 months, indicating that immunologic tolerance to porcine fVIII was achieved. Furthermore, transplantation of bone marrow from primary recipients into naive secondary recipients resulted in sustained, high-level fVIII expression demonstrating successful genetic modification and engraftment of HSCs.

• Authors: Bagirath Gangadharan, Ernest T Parker, Lucienne M Ide, H Trent Spencer, Christopher B Doering
• Journal: Blood (Blood) Vol. 107 Issue 10 Pg. 3859-64 (May 15 2006) ISSN: 0006-4971 [Print] United States
• PMID: 16449528 (Publication Type: Journal Article, Research Support, Non-U.S. Gov't)

Chemical References

• Green Fluorescent Proteins
• Factor VIII

Topics

• Animals
• Animals, Genetically Modified
• Bone Marrow Cells (cytology)
• Disease Models, Animal
• Exons
• Factor VIII (genetics)
• Green Fluorescent Proteins (genetics)
• Hemophilia A (therapy)
• Humans
• Mice
• Mice, Inbred C57BL
• Mice, Transgenic
• Stem Cell Transplantation
• Stem Cells (physiology)
• Swine (genetics)
• Transplantation, Heterologous