Marcelo Cypel, Institute of Medical Sciences, UofT, University Health Network

The ability to preserve lungs prior to the time of transplantation has made lung transplantation a clinical reality for those with end-stage lung disease. Currently. lung preservation is performed by flushing the organ with an organ-specific solution. and subsequently storing the organ on ice where it rests at approximately 4’C. Using this approach. preservation times are limited to clinical times of approximately 6-8 hours. Longer preservation times will allow for the overcoming of geographical hurdles faced in organ donation. allow for more optimized donor and recipient matching. and progress lung transplantation towards a semi-elective procedure. Previous reports have shown increased mitochondrial degeneration during prolonged cold storage periods. with an association of worsening graft function. In this project. we aim to explore the specific role of organ temperature during lung preservation on mitochondrial health during the preservation period. with hopes of optimizing the current temperature being used to store lungs. With these findings. we further hope to explore new therapeutic approaches of mitochondrial protection during the cold preservation period such as mitochondrial transplantation and anti-oxidative metabolite preservation solution supplementation

Ana Andreazza, Department of Pharmacology and Toxicology, University of Toronto

Thomas Hurd, Department of Molecular Genetics, University of Toronto

Currently, treatments for mitochondrial dysfunction/disease are limited to antioxidants and compounds targeting specific mitochondrial proteins. however. an emerging approach is the transplant of freshly isolated mitochondria to injury sites. The use of mitochondrial transplants presents several challenges. including the need to identify autologous mitochondria with low levels of mitochondrial DNA (mtDNA) mutations. Therefore,the overall objective of this study is to identify and optimize novel protocols for autologous mitochondrial transplantation in patient-derived induced- pluripotent stem cells (iPSCs). Specifically. we will: (2) Define the best method to reduce or eliminate mutant mtDNA in patient-derived iPSCs: and (2) Establish an efficient and stable mitochondrial delivery method. To date. we have finalized the mitochondrial isolation protocol and are in the process of optimizing the reintroduction of isolated mitochondria into po cells lacking mtDNA.

Thomas Hurd, Department of Molecular Genetics, University of Toronto

Ana Andreazza, Department of Pharmacology and Toxicology, University of Toronto

Mitochondrial DNA (mtDNA) is indispensable as it encodes components essential for ATP production. Despite its importance. limited recombination and repair mechanisms result in high rates of mutations in mtDNA which contributes to disease. Unfortunately, most tissues are incapable of selectively recognizing and degrading mutant mtDNA. The female germline. the tissue which gives rise to eggs. is unique. in that it is capable of selectively eliminating mutant mtDNA We aim to uncover the mechanism through which the germline does this in order to manipulate these processes to eliminate mutant mtDNA from diseased tissues. We have identified a number of proteins that play a critical role in eliminating mutant mtDNA from the germline and are currently determining mechanistically how they work together to selectively eliminate mutant mtDNA.

Jason Moffat, Department  of Molecular Genetics, University of Toronto

Charlie Boone, Department  of Molecular Genetics, University of Toronto

Genetic interactions (GI) occur when mutations in multiple genes combine to generate an unexpected phenotype. and aid in our understanding of genotype-to-phenotype relationships in both health and disease. By investigating Gl’s, we can map functional relationships between genes that can be used for identifying genetic elements involved in biological processes and disease. elucidate gene function. and discover therapeutic targets. The disease that has become a driver of my interest in how GI’s involving two or more genes can contribute to an individual’s disease phenotype is Barth Syndrome. rooted in mutations in the gene TAZ There is extreme variability observed in Barth Syndrome patients even though one gene is responsible for this disease. suggesting that there are modifier genes or additional variants of TAZ that could be involved. My project aims to generate the first genetic interaction profile of the TAZ gene using a highly sensitive genome- wide CRISPR/Casg screening platform. In parallel this project aims to generate the first comprehensive reference genetic interaction map of the mitochondria in human cells. exploring relevant disease alleles and GI’s involved in both physiological and pathological conditions.

Martin Beaulieu, Department of Pharmacology and Toxicology, University of Toronto

Peter McPherson, Department of Pharmacology and Toxicology, University of Toronto

The project is designed to establish a link between psychiatric illnesses risk gene FXR1 and mitochondrial function that could explain mitochondrial malfunction in the patients with disorders such as schizophrenia and bipolar disorder. Firstly. we are planning to establish a molecular phenotype of mitochondria using cell culture models and CRISPR-Casg approach to target the gene of interest. Secondly. we will pursue a similar approach to knockout the gene of interest in cortical neurons of adult mice using viral delivery to check for mitochondrial phenotype. And at last. we plan to test if the protein of interest exhibits protective function against oxidative stress in mitochondria.

Ruth Slack, Cellular and Molecular Medicine, University of Ottawa

Strong evidence suggests a key role for adult neurogenesis in tissue regeneration and cognitive function. Understanding the regulation and persistence of neural stem cells (NSC) in the adult brain is critical for real-life application in neurodegenerative diseases. Our group has shown that mitochondrial function plays a pivotal role in regulating NSC and cognitive function. Our goal is to identify how mitochondrial dynamics and metabolism regulate neurogenesis and learning and memory. Unbalanced mitochondrial dynamics results in mitochondrial fragmentation. which is seen during aging and at an accelerated rate in neurodegenerative diseases Optic atrophy 1 (OPA1. a gene implicated in Parkinson’s Disease and Dominant Optic Atrophy) facilitates mitochondrial fusion and regulates energetics We use Opat inducible knockout in mouse NSCs to model accelerated aging and neurodegeneration. We show that Opai loss leads to mitochondrial dysfunction which induces a cascade of cellular stress response that regulates cell survival at the expense of NSC proliferation.

This study reveals how mitochondrial dysfunction. typical of neurodegenerative diseases alters NSC fate decisions and identifies new regulatory targets by which to enhance mitochondrial function in the context of neurodegeneration. Modulating such stress conditions posed here opens new avenues in neurodegenerative disease therapeutic strategies