Developing treatments for mitochondrial DNA diseases. (360G-Wellcome-094868_Z_10_Z)

We will test whether mitophagy (a catabolic process involving recycling of damaged mitochondria) is important in mitochondrial disease. We aim to overcome the technical difficulties of studying mitophagy using: (1) ImageStream (which combines flow cytometry and fluorescence microscopy in a single platform) to investigate patient-derived cell lines. We will explore how mitophagy is affected in cells with defects of mtDNA maintenance, from patients and from the POLG1 deficient Mutator mouse. We will explore whether mtDNA mutant populations can be manipulated by modulating mitophagy, for instance by amino acid starvation and exposure to certain drugs including rapamicin and chloroquine. (2) a mouse model in which mitophagy may be readily detected by florescence microscopy. This involves crossing two existing transgenic strains in order to breed mice in which mitochondria and lysosomes both constitutively express fluorescent markers. Mitophagosomes would thus be detectab le by co-localisation of these signals, providing a marker for response to therapies. This mouse will be crossed with an existing model (the Deletor mouse) to determine how candidate treatments (including ketogenic diet) affect mitophagy. These approaches will be extremely useful tools for investigating multiple mitophagy-related pathologies and mouse models of mtDNA diseases and ageing.