Approximately 5% of the world's population suffers from anemia due to mutations in the human globin gene. While the mutations that cause Cooley's anemia (CA) and sickle cell anemia (SCA) are well known, the major curative treatment, allogenic bone marrow transplantation (BMT), is not meant to repair the defective genes but simply replace the diseased bone marrow with cells from an allogenic donor. Currently, allogenic BMT procedure is fraught with high morbidity and mortality and is available only to those with a suitable donor. The alternative is autologous gene or cellular therapy. Current gene therapy protocols rely on the transduction of millions of hematopoietic cells with randomly integrating virus followed by their transplantation back into the patient. Insertional mutagenesis by one of the millions of viral integrations is a real and dangerous problem in these protocols. The recent excitement of patient-specific induced pluripotent stem (iPS) cells for the production of autologous cells for therapy has been tempered by the discovery of reprogramming-induced genomic mutations and the lack of efficient protocols for producing transplantable hematopoietic stem cells (HSCs) in vitro. This project takes a straightforward autologous approach to cure hematopoietic disorders by direct genome editing of the patient's hematopoietic stem cells (HSCs), thereby avoiding the morbidity and mortality of allogenic BMT, insertional mutagenesis of gene therapy, or reprogramming-induced mutations and problems of directed hematopoietic differentiation associated with iPS cell approaches. The primary goal of this research is to cure CA and SCA by directly editing the DNA in mutant HSCs. The first Specific Aim will utilize preclinical humanized mouse models of CA and SCA in proof of principle studies to cure these disorders by direct adult HSC therapy. In the second Specific Aim, gene editing of embryonic stem cells derived from human hemoglobin mice are used to generate novel humanized models of hemoglobinopathy and thalassemia. The major goal of the last Specific Aim is to cure CA by allogenic BMT in the absence of any cytoreductive conditioning or long-term immune suppression of the recipient;thereby, eliminating potentially lethal side effects of current therapy. Successful completion of these studies will demonstrate safe and effective novel treatment regimens for the correction of CA and SCA. Furthermore, these methods should be translatable to the autologous treatment of many more hematopoietic disorders in addition to hemoglobinopathies and thalassemia.
The major goal of this research is to cure sickle cell anemia and beta thalassemia major by directly editing the DNA in autologous hematopoietic stem cells (HSCs) from patients. Transplantation of the corrected HSCs back into the patient will provide a safer alternative to current gene therapy or allogenic transplantation. These methods should be translatable to the autologous treatment of many hematopoietic disorders.