Rodriguez 2019 Abstract IOC141

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Rodriguez E, Camus FM, Lane N (2019) Mitochondria as “flux capacitors”: the effect of mitonuclear incompatibilities on mitochondrial physiology, metabolomics profile and gene expression in D. melanogaster. Mitochondr Physiol Network 24.02.

Link: IOC141

Rodriguez E, Camus FM, Lane N (2019)

Event: IOC141

Recent findings place mitochondria as more than simple “powerhouses” of eukaryotic cell, because of their fundamental role in regulating cellular function. Mitochondria integrate metabolic flux and stress, signal the physiological status of the cell to the nucleus and coordinate nuclear gene expression accordingly: they can thus be seen as “flux capacitors”. This idea fits with their important implication in a wide range of diseases and the aging process, although the molecular mechanisms behind this remain poorly understood. An important feature of mitochondrial function is the fact that the respiratory proteins of the electron transport system are encoded by 2 genomes: nuclear and mitochondrial, which differ in their mode of inheritance and mutation rates. Incompatibilities or even subtle mismatches arising from mutations in either genomes can profoundly affect protein and cellular function, gene expression, to the point of disrupting normal health, fertility and lifespan. The consequences of these mismatches can be difficult to predict because of the variable penetrance of mtDNA mutations and their tissue specificity (among others), meaning that mitochondrial function can be affected by diet, temperature and stress in different ways. Linking alterations in mitochondrial function to changes in downstream metabolic flux and differences in gene expression is therefore needed to understand the underlying signalling processes. In order to do so, Drosophila melanogaster can prove a useful model whereby manipulations of the mitochondrial and nuclear genomes can create genotypes that vary in the degree of match, and yield individuals on which fine-scale biochemical and genetic analysis can be performed. We aim to test the effects of three different treatments (2 drugs, 1 diet) in 1 coevolved and 2 mismatched fly lines. One of these mismatched lines harbors 30 SNPs differences in their mtDNA (compared to wild-type), mostly in complex I of the electron transport system, while the other has a single critical SNP difference at the level of complex IV. The drugs N-acetyl cysteine (NAC, an antioxidant modulating oxidative stress via glutathione metabolism), and Nicotinamide Riboside (NR, a precursor of NAD synthesis), will be tested; while the dietary treatment will consist in a high protein diet, which can alter TCA cycle flux via changes in carbohydrate and amino acid metabolism. Using the O2k-FluoRespirometer in different respiratory states, we will measure mitochondrial respiration, ATP synthesis, H2O2 flux, and membrane potential in adult thorax and reproductive tissues, of male and female flies at three time points during their lifetimes. Following these mitochondrial physiology measurements, we will look at the effects of the treatments on metabolomic profiles, gene expression and phenotype (fertility and longevity) to ultimately construct a predictive metabolic flux model.


Bioblast editor: Plangger M


Labels: MiParea: Respiration, mtDNA;mt-genetics, nDNA;cell genetics, Exercise physiology;nutrition;life style, Pharmacology;toxicology 


Organism: Drosophila 


Regulation: ATP production, mt-Membrane potential 


HRR: Oxygraph-2k, O2k-Fluorometer 


Affiliations

Dept Genetics, Evolution Environment, Univ College London, UK