Increasing Clonal Diversity of Genetically Modified HSC

Gene therapy of inherited blood diseases requires harvest of hematopoietic stem cells (HSCs) from patients, viral mediated gene transfer of the corrected gene and autologous transplantation of genetically modified cells. In order to achieve correction of the disease, high number of hematopoietic stem cells and previous conditioning of the host bone marrow (BM) are required. Additionally, the transplant should be a pool of diverse cells to avoid a skewed reconstitution of the hematopoietic system. Conventional sources of HSCs are either BM or cells that are "mobilized" to egress the BM and circulate in the peripheral blood. However, these sources are not feasible for all patients. In this project, we will explore new sources of HSCs and molecular tools to increase clonal diversity in the transplant. We will have the unique opportunity to study and characterized HSCs that will be mobilized from the BM of adult thalassemic patients by treatment with the new drug Plerixafor (AMD3100), in the context of a Phase-II trial. The final goal will be to evaluate these cells as a source of HCSs for gene therapy in adult patients. Additionally, we will investigate the use of a modified growth receptor able to confer a selective advantage to cells expressing this molecule. Understanding the molecular basis of the events leading to better survival and engraftment of the corrected cells will provide new tools to improve gene therapy strategies.