Retroviral WASP gene transfer into human hematopoietic stem cells rescues phenotype in myeloid progeny cells.

RICARDO A. DEWEY; M. BALLMAIER; S. EHL; L. FILIPOVICH; W. FRIEDRICH; J. GREIL; T. GÜNGÖR; C. HAPPEL; IRINA KONDRATENKO; U. PANNICKE; K. SCHWARZ; KARL WELTE; CHRISTOPH KLEIN

Dusseldorf

Jornada; 22. Jajrestagung der Arbeitsgemeinschaft Pädiatrische Immunologie e.V.; 2005

Arbeitsgemeinschaft Pädiatrische Immunologie e.V.

Wiskott-Aldrich-Syndrome is caused by mutations in the gene encoding WASP (Wiskott-Aldrich-Syndrome-Protein), a hematopoietic-specific cytosolic protein regulating the actin cytoskeleton. The only curative treatment consists in allogeneic hematopoietic stem cell (HSC) transplantation, a procedure associated with high morbidity and mortality. In previous studies, we have shown that the transplantation of retrovirus-transduced HSC can correct the phenotype in a WASP-deficient murine model system. Here, we investigate whether the reconstitution of human WASP-deficient CD34+ with GALV-pseudotyped WASP-IRES-GFP encoding retroviral vectors would correct the phenotype of myeloid progeny cells. We used HSC from five patients and differentiated purified WASP-transduced and GFP-transduced cells into CD14+ macrophages. We also studied whether WASP overexpression in CD34+ cells from healthy donors would cause any toxic effects. We found that mRNA and protein levels could be restored in CD14+ cells derived from WASP-transduced HSC. Cellular functions depending on normal actin cytoskeleton rearrangement such as podosome formation and Fc-mediated phagocytosis were restored in WASP-transduced myeloid cells but not in GFP-transduced controls. Furthermore, WASP-transduced cells showed a significant growth advantage over control-transduced cells in myeloid differentiation conditions. Overexpression of WASP in CD34+ cells from normal donors did not change their differentiation potential as assessed in CFU assays. In conclusion, our studies document the feasibility of WASP gene transfer into human CD34+ cells and suggest that the phenotype of WASP-deficient myeloid cells can be restored upon retroviral gene transfer.