Intracellular selection and dynamics of mitochondrial ageing
Description: Eukaryotic cells contain multiple mitochondrial genome (mtDNA) copies, which encode proteins required for mitochondrial energy production. Maintaining intact mtDNA is critical for cellular and organismal health and its deterioration has been linked to cellular aging. mtDNA is known to mutate at an elevated rate, but extensive evidence also suggests the existence of processes, acting on cellular and subcellular levels, that eliminate damaged mtDNA thus acting to rejuvenate mitochondria. Yet mtDNA integrity declines during ageing, but the timecourse of its decay and the underlying mechanisms remain largely unknown, because of challenges presented by the complex and quantitative nature of involved phenotypes. This project will address these challenges through a multidisciplinary approach that applies yeast as a model organism and combines novel mtDNA-based reporters, special purpose optofluidic devices and advanced mathematical modelling. Our goal is to understand (a) the link between mtDNA decay and physiological changes associated with the ageing process at the single cell level; (b) the mutational events that drive mtDNA decay with single cell sequence resolution and (c) the processes that facilitate intracellular selection against mutant mtDNA and their role in suppressing mtDNA decay during ageing.
Specifically, we will use mtDNA-based fluorescent reporters for mtDNA copy number and expression to infer mtDNA health throughout the ageing process while monitoring the decline of physiological parameters in single cells. To do so, we will develop a novel device that combines optofluidics with advanced fluorescence microscopy to monitor, select and sort single cells during the ageing process and eventually subject them to whole genome amplification and sequencing in a highly parallelized manner to determine mtDNA sequence changes. This will allow us to monitor mitochondrial function and mtDNA variation with cell age and between ancestrally related cell lineages. Resulting data will be analyzed quantitatively with the help of mathematical models of mtDNA propagation within cells, including effects of mutation, selection and random drift, which will enable us to specifically address the role of intracellular purifying selection in extending the mitochondrial healthspan of a cell. Our findings will provide broad fundamental insight into mitochondrial biology.
Funder: Human Frontier Science Program
Amount: $1,200,000
Funding type: award
Start date: 2023-08-01
End date: 2026-07-31
Investigators: Christof Osman, Michael Krieg, Boris Shraiman
Institutions: Ludwig-Maximilians-Universitaet Muenchen (LMU Munich), ICFO – The Institute of Photonic Sciences, The Regents of the University of California, Santa Barbara
Subfield: Molecular Biology
Domain: Life Sciences
Funded outputs count: 1
Funder award ID: RGP021/2023
OpenAlex ID: G7553408611