Develop a Preclinical Model for Gene Therapy of Fanconi Anemia Group C
Abstract
Bone marrow failure (BMF) happens when the bone marrow cannot produce enough normal blood cells, including red blood cells, white blood cells, or platelets. Thus, a patient without treatment cannot distribute oxygen throughout the body’s tissue, cannot fight infection, and are unable to stop bleeding. BMF is the leading cause of early death in patients with Fanconi Anemia (FA). FA is the most common inherited BMF disorder and is also associated with congenital abnormalities and cancer predisposition. FA is caused by mutations in any member of the FA gene family, which is crucial for removing DNA damage and maintaining genome integrity. About 90% of patients have mutations in FANCA, FANCG, or FANCC genes. FANCC-mediated FA (group C) patients show typical clinical symptoms of FA. There is no cure for this disease. Current treatment strategies focus on mitigating symptoms of BMF, treating secondary cancer, and improving the life quality of patients. BMF can be treated by allogeneic stem cell transplantation from a matched donor. However, besides the frequent unavailability of matched donors, transplanted FA patients have an enhanced risk of developing graft-versus-host disease. A personalized approach that overcomes the limitations of allogeneic stem cell transplantation is to use gene therapy that corrects mutations in patient-derived stem cells, and then transplant the corrected stem cells back into the patient. Indeed, lentivirus-based delivery of functional FA genes into patient-derived stem cells can restore functions of patient stem cells. The corrected stem cells can be engrafted into a patient without conditioning, thus mitigating the BMF symptom. However, random integration of the viral genome into the host genome and the inability to control the expression of the transgene are major safety concerns. Thus, precise mutation correction in patient-derived stem cells is crucial for safe gene therapy of FA. CRISPR/Cas9 is the state-of-the-art technology that allows modifying the genome seamlessly. Scientists have used this technology to precisely correct mutations in blood stem cells that can be applied for the treatment of blood genetic diseases (sickle cell, beta-thalassemia, and primary immune deficiency). This approach specifically introduces double-stranded breaks (DSB) into the genome and precisely repairs it via a DNA repair pathway called Homology-Directed Repair. However, DSBs may cause extensive genetic abnormalities. FA patient-derived cells have reduced ability to repair DNA damage; thus, CRISPR/Cas9-induced DSBs might harm the cell functionality. Hence, an approach that introduces few to no DSBs is ideal for gene therapy of FA disease. We have recently developed a Spacer-Nick system that can efficiently correct mutations in blood stem cells while mitigating all the adverse effects of DSB. Here, we will exploit the Spacer-Nick system to correct mutations in FA group C patients. We will place a functional copy of the FANCC gene into the original site of the FANCC gene in patient-derived blood stem cells. We hypothesize that corrected stem cells will express a normal level of the FANCC gene product and restore the blood cell production and function both in laboratory tests and in living animals. We have developed and shown that the Spacer-Nick system works efficiently in healthy blood stem cells. In this proposal, we will apply that system to correct FANCC mutations in two systems: blood stem cells from mice that don’t express the Fancc gene, and blood stem cells isolated from FA patients. We will validate the functions of corrected stem cells in these two preclinical models. This proposal fits well with the award focus area to find effective BMF treatments and cures for FA-related BMF disease. Our proposal is innovative because our new gene-editing system will provide a universal gene therapy that benefits all patients with FANCC mutations. In addition, our innovative approach
Document Details
- Document Type
- DoD Grant Award
- Publication Date
- Jan 04, 2024
- Source ID
- HT94252310371
Entities
People
- Ngoc Tung Tran
Organizations
- Indiana University
- United States Army