Towards Humanized Mouse Models of Mitochondrial Disease
Abstract
FY20 PRMRP Topic Area addressed by the proposed research project: Mitochondrial disease. Area of Encouragement: Development of improved tools and animal models to study primary mitochondrial diseases and evaluate therapeutics. Rationale: Mutations in mitochondrial DNA (mtDNA) are a prevailing cause of mitochondrial diseases, which can be fatal and can affect anyone, including military personnel and their families. Currently, treatment options for mitochondrial diseases are limited to symptom control and palliative care. Animal models of human disease are instrumental in developing and testing new drugs, but unfortunately, no faithful mouse models are currently available to facilitate research on or drug development for mitochondrial disease. Present-day methods for generating mouse models of mitochondrial disease depend on the availability of mouse cells that carry mtDNA mutations equivalent to those found in human disease. However, such mutations are often impossible to induce, even using gene editing techniques. Over the past 30 years, humanized mice have revolutionized the study of human hematology and immunology and have proved superior in some respects even to non-human primate models. However, “humanization” in these models remains confined to the immune system. The long-term goal of this application is to humanize mice by reconstituting the human mitochondrial respiratory system in these animals. This would not only radically alter our approach to modeling mitochondrial disease by allowing the use of patient mtDNA from peripheral blood as starting material, but also would enable the creation of faithful models of those mitochondrial diseases, which are impossible to model using the contemporary approach. The first stumbling block on this road is the inability of murine cells to stably maintain human mtDNA. Our hypothesis, therefore, is that the instability of human mtDNA in mouse cells can be overcome by introducing one or several human genes responsible for mtDNA maintenance into these cells. It is important to note here that the latest findings in the field of mtDNA research support the feasibility of our approach. Early attempts to replicate human mtDNA in murine cells in the 1970s and 80s failed due to the unavailability of molecular tools necessary to dissect the complexities of the issue, as well as the lack of knowledge of mitochondrial diseases, which were only discovered in the late 1980s, to motivate research. In this application, we will, for the first time, attempt to identify the gene(s) that will enable replication of human mtDNA in murine cells. Today, we have at our disposal resources and techniques that previously weren’t even on the horizon (including PCR, somatic cell hybrid and radiation hybrid approaches, genome sequences for humans and mice, affordable whole genome sequencing by Next Generation Sequencing, and others). The ultimate outcome of the proposed line of research is a “humanized” murine platform for modeling mitochondrial disease using patient mtDNA. This platform will trivialize the existing crippling bottleneck in technology, which has thus far prevented the generation of accurate mouse models of mitochondrial disease caused by mtDNA mutations. It will do so by enabling the generation of an individualized mouse model from a sample of patient blood. In the short term, the proposed studies will expand our understanding of mtDNA replication. They will also stimulate research into the poorly understood mechanisms of interaction and coordination between the nuclear and mitochondrial genomes by providing a novel platform and tools for these studies. If successful, the proposed studies will lay the foundation for projects aimed at the optimization of transcription, translation, and/or respiratory chain function (as necessary) in humanized mouse cells. In the long term, these studies will lead to the emergence of a conceptually new approach to modeling mitochondrial dise
Document Details
- Document Type
- DoD Grant Award
- Publication Date
- Dec 05, 2021
- Source ID
- W81XWH2110669
Entities
People
- Mikhail F Alexeyev
Organizations
- United States Army
- University of South Alabama