Development and functional validation of a gene editing approach in hematopoietic precursor cells for Wiskott-Aldrich Syndrome

The Wiskott-Aldrich syndrome (WAS) is an X linked disease caused by a defect in the WAS gene.
Affected individuals suffer from recurrent infections, eczema, bleeding, auto-immune symptoms
and an increased risk of leukemia. Since WAS protein is involved in the signal transfer from the T
cell receptor to the cytoplasm, the lack of this protein will result in a suboptimal immune
responses to pathogens. In addition, T cell differentiation and development of a broad repertoire
is compromised in some patients depending on the nature of the mutation. Current treatment
consists of stem cell transplantation from an HLA matched disease-free donor. However, allogenic
transplantation frequently causes severe side-effects, especially graft-versus-host disease. The
goal of this project is to set up and further optimize a new therapy for WAS based on gene editing.
Gene editing is a technique in which the defective gene is replaced by the functional gene. To
functionally validate this technique, healthy male hematopoietic stem cells will be genetically
altered to express either a particular mutated WAS gene(s) or the wild type WAS gene. Using the
in vitro T cell differentiation system on OP9-DL1 cells and in vivo systems using immune deficient
mice, the functionality of mature T cells, T cell differentiation and repertoire, generated from
hematopoietic precursors carrying one of the mutant genes or the wild type gene, will be studied.
These data constitute important preclinical data.