A New In Situ Cryo-Electron Microscopy Approach to Directly Visualize Mutations in Mitochondrial Disease
Abstract
Topic Area: Here we propose a novel approach to accurately diagnose and treat mitochondrial disease. We will directly address the Fiscal Year 2019 Peer Reviewed Medical Research Program Topic Area of Mitochondrial Disease. The proposed work is of significant relevance to the healthcare needs of active Service members, Veterans, and beneficiaries. Statement of Problem: Mitochondria are cell organelles essential for fueling most of the body’s energy requirements. Optimal mitochondrial function is critical for peak physical and mental performance and is dependent upon the structural integrity of the mitochondrial respiratory complexes within this organelle. Mitochondrial diseases are often caused by mutations that disrupt the structure of the mitochondrial respiratory complex machinery. These alterations in mitochondrial structure lead to impaired mitochondrial function that produce a broad range of symptoms including cardiomyopathy and serious neurological deficits. Furthermore, substantial numbers of people are affected by mitochondrial dysfunction associated with highly prevalent diseases including diabetes, Alzheimer’s disease, Parkinson’s disease, epilepsy, stroke, and cancer. The combined impact of these mitochondrial impairments is enormous. Many members of the US military, Veterans, and beneficiaries suffer from mitochondrial disease or disorders associated with mitochondrial dysfunction. Veterans are especially affected by a variety of chronic, deployment-associated conditions linked to impaired mitochondrial function including Gulf War Illness (GWI). Exposure to toxicants including pesticides such as Agent Orange or paraquat in military theater have also been negatively associated with Veterans’ health post-deployment. Yet, the precise mechanisms responsible for mitochondrial disease and dysfunction remain poorly understood. Significantly, our ability to accurately diagnose disturbances in mitochondrial function also remains profoundly limited. Current diagnostic approaches cannot resolve specific disease-causing mitochondrial structural defects despite evidence of broader mitochondrial dysfunction. Such approaches are often invasive and may alter the appearance of mitochondria, hindering accurate diagnosis. Thus, there is great clinical need for accurate diagnostic approaches since better diagnosis will translate to more effective treatments and improved patient outcomes. Overview: In situ cryo-electron tomography (cryo-ET) imaging is a groundbreaking new three-dimensional imaging approach with the resolution to visualize changes within individual biological molecules or clusters of molecules. We will employ this powerful new imaging method to visualize disease-induced changes in mitochondrial structure directly in the cells of patients with mitochondrial disease for the first time. The unprecedented resolution provided by cryo-ET will permit us to visualize alterations in mitochondrial respiratory complex structures unique to disease-causing mutations and/or acquired mitochondrial defects. Our proposal will employ this novel imaging method, together with new image recognition computational approaches, to rapidly and accurately identify the structural alterations in the respiratory complexes responsible for disease-causing impairments in mitochondrial function. We will test our approaches in several preclinical models of mitochondrial disease including cells from patients with Leigh Syndrome (LS), a debilitating mitochondrial disease, as well as in cells from Veterans suffering from GWI. We will also directly visualize effects of toxicants known to produce GWI-associated mitochondrial dysfunction on mitochondrial structure. Lastly, we propose to treat both LS and GWI patient cells with novel drugs that improve mitochondrial respiratory function and determine whether the drugs’ therapeutic efficacy is due to the ability to correct mitochondrial structural abnormalities. Impact: Mitochon
Document Details
- Document Type
- DoD Grant Award
- Publication Date
- Mar 10, 2021
- Source ID
- W81XWH2010113
Entities
People
- Zachary Freyberg
Organizations
- United States Army
- University of Pittsburgh