ANT1 Gene Therapy for the Treatment of Mitochondrial Disease
Abstract
Background: Primary mitochondrial diseases (PMD), resulting from mutations in mitochondrial genes in either the nuclear DNA (nDNA) or mitochondrial DNA (mtDNA), affect both children and adults by impairing the function of the most energy demanding tissues: the brain, heart, and muscle. Children with PMD associated with heart disease (cardiomyopathy) are almost three times more likely to die than PMD children without cardiomyopathy, and heart failure is a leading cause of death in adults. Therefore, we need to develop an effective genetic treatment for mitochondrial cardiomyopathy. Yet a recent review stated that while gene therapy has been generally successful, not a single application targets any disease affecting the heart, and this failure is partly due to the lack of appropriate animal models of mitochondrial heart disease. Rationale: We have studied the PMD resulting from mutations in the nDNA-coded mitochondrial gene, the heart-muscle adenine nucleotide translocator (ANT1). The ANT1 protein is responsible for the export of ATP (energy transporting chemical) out of the mitochondrion to the rest of the cell. ANT1-deficient patients develop cardiomyopathy, the severity of which is determined by mtDNA genes: milder disease results in hypertrophic cardiomyopathy while more severe disease results in life-threatening dilated cardiomyopathy. We have succeeded in modeling ANT1 PMD by inactivating the mouse Ant1 gene and shown that the severity of the cardiomyopathy is also determined by the mtDNA. Using our unique mouse model system, we have succeeded in partially correcting Ant1-deficient cardiomyopathy by transferring the normal Ant1 gene into the mouse heart carried by the Adeno-Associated Virus (AAV). Hypothesis/Objective: By using our unique Ant1 model of PMD cardiomyopathy, we propose to perfect the use of AAV gene therapy in treating mitochondrial cardiomyopathy in hopes of curing ANT1 cardiomyopathy and developing procedures applicable to other mitochondrial cardiomyopathies. Specific Aims and Study Design: In our quest to cure mitochondrial cardiomyopathy, we propose to pursue three specific aims: (1) use the Ant1-deficient mouse to perfect the AAV system for delivering mitochondrial genes to the heart, (2) use the Ant1-deficient mouse to investigate how the AAV-Ant1 virus cures the mitochondrial physiological and molecular defects of the heart, and (3) use an optimized AAV-ANT1 virus to cure human mitochondrial cardiomyopathy cells generated from patient skin cells by development reprogramming. In Specific Aim 1, we will identify the optimal AAV for carrying and expressing the Ant1 gene in Ant1-deficient mouse heart, develop the best approach for introducing the virus to the heart in young and old mice, and confirm that gene delivery and expression is safe. In Specific Aim 2, we will confirm that the virus repairs the mitochondrial defects in the heart, determine the heart cells that express the therapeutic gene, and determine the extent to which the AAV-Ant1 virus normalizes heart cell gene expression. In Specific Aim 3, we will treat human cardiomyocytes in cell culture with the AAV-ANT1 virus, confirm expression of the introduced ANT1 gene, document the repair of the mitochondrial energetic defects, demonstrate restoration of normal heart cell contraction, examine the restitution of normal nuclear gene expression, and confirm the lack of toxicity to human heart cells. Impact: By developing an effective AAV gene therapy for curing the heart disease of ANT1-deficient patients, we hope to save the lives of the severely affected ANT1-deficient children and to enhance the quality of life of the ANT1-deficient adults. Since chronic mitochondrial dysfunction could be a frequent cause of heart disease in children and adults, these efforts could guide the development of gene therapy approaches for other mitochondrial cardiomyopathies, and thus have broader application for the cardiac problems of military pe
Document Details
- Document Type
- DoD Grant Award
- Publication Date
- Dec 28, 2022
- Source ID
- W81XWH2210560
Entities
People
- Douglas C Wallace
Organizations
- United States Army