FINAL PROGRAM - American Society of Gene & Cell Therapy

13 th AnnUAL MEETing | Washington, DC USA May 19-22, 2010 57Program ScheduleScientific Symposium 31310:30 am - 12:30 pmRoom: Maryland SuitePrecise Genetic and Post-transcriptional Modification of Stem CellsChairDieter C. Gruenert, PhDSpeakersPeter M. Glazer, MD, PhDTargeted Gene Modification in Hematopoietic Stem Cells via Triple Helix FormationTriple helix-forming peptide nucleic acids (PNAs) can bind to polypurine regions in DNA in a sequence-specific manner. The resulting triplexes constitute an altered DNAstructure that can stimulate DNA repair and recombination in a site-specific manner in human cells. We have found that transfection of human hematopoietic stem cellswith triplex-forming PNAs plus short single-stranded donor DNAs can produce targeted modification of disease related genes. Site-directed modification of two key humangenes has been achieved: (1) the human beta-globin gene, mutations in which cause thalassemia and sickle cell anemia; and (2) the CCR5 gene, which encodes aco-receptor for HIV-1 entry into human cells. Triplex-modified hematopoietic stem cells have been transplanted into immune deficient mice, with full engraftment, normalpatterns of differentiation, and persistence of the targeted gene modification for up to four months.Linzhao Cheng, PhDGene Targeting in Human Pluripotent Stem CellsHuman induced pluripotent stem (iPS) cells reprogrammed from adult somatic cells resemble embryonic stem (ES) cells that can proliferate indefinitely in culture whilemaintain their full differentiation potential (pluripotency), therefore providing an unlimited resource for disease research and therapy. These self-renewable stem cells alsomake it feasible to achieve gene targeting (to correct or create DNA mutation) in the genome of normal human cells by homologous recombination (HR) that is naturalbut inefficient process for genome repair. To enhance HR-mediated gene targeting efficiency we also incorporate the strategy utilizing zinc finger nuclease (ZFN), whichis designed as a fusion protein with multiple zinc-finger DNA binding and the FokI endonuclease domains. Upon dimer formation, two ZFNs (co-delivered with a donorDNA template) can create a sequence-specific DNA double strand break to stimulate HR near the cut site. We found that ZFNs enhanced HR by >100-1,000 fold in eithercreating or correcting a mutation in human iPS and ES cells.Dieter C. Gruenert, PhDModification of the CF and Sickle Cell Anemia iPS cells by SFHRInduced pluripotent stem (iPS) cells have the potential of significantly advancing the development of stem cell-based therapies, especially as they pertain to inheriteddiseases. The potential to generate autologous pluripotent stem cells to repair and regenerate tissues and organs damaged by disease pathologies is a cornerstone ofpatient-specific therapy. Cystic fibrosis (CF), the most common inherited disease in the Caucasian population, and sickle cell anemia (SCA), the most prevalent hemoglobinopathycommonly found in individuals of African, Middle Eastern, Mediterranean, and Southeast Asian decent, have significant multiorgan damage that will benefit fromcellular repair. In this context, somatic cells from a CF patient with a ∆F508/∆F508 genotype and a SCA patient have been reprogrammed, characterized, and correctedby small fragment homologous replacement (SFHR).Robert Blelloch, MD, PhDMicroRNA Regulation of Embryonic Stem Cell Self-Renewal and DifferentiationFriday, May 21 st