Objectives. Our aim is the identification of drugs with therapeutic effects on mitochondrial (mt) pathologies linked
to POLG or POLG2 genes, encoding the mt DNA pol and its accessory subunit. We will adopt a multi-species
approach, based on drug pre-screen in Polg-mutated yeast (mip1) and C. elegans (polg-1) strains, followed by
drug validation in zebrafish (zf) Polg and Polg2 mutants.
Background. The therapeutic treatment of POLG diseases is currently limited to symptom management. Mouse
Polg models appear poorly suitable for large-scale drug screen compared to simpler and cost-effective models
such as unicellular (yeast), invertebrate (worm) or non-mammalian vertebrate (zf) organisms. We have already
identified a panel of yeast/worm-prescreened drugs, worth to be investigated in a vertebrate setup; in parallel,
we have generated both Polg and Polg2 zf mutants, faithfully modeling the human condition.
- In-depth characterization of the rescuing effect of yeast/worm pre-identified molecules, and large-scale
screen of a FDA/ICCB drug library using yeast mip1 mutants
- Screen of positive hits in zf Polg models
- Validation of candidate molecules in zf Polg2 mutants and alternative models for mt dysfunction
Methods. The screen of drugs in yeast will be performed by evaluating the rescue of respiratory growth defect
due to mtDNA instability (“petite” phenotype) in mip1 mutants. More in-depth analysis will include quantitative
evaluation of Mip1 expression, respiratory activity and mtDNA levels. Positive hits will be analyzed in zf Polg
models, evaluating the rescue of pathological phenotypes, including mtDNA depletion (MDD), impaired
respiratory activity and altered mt-nucleus retrograde signaling.
- Collaborative papers on: an identified compound, CLO, working in all models; new drugs to be
determined; zf polg, polg2 and transgenic lines for MDDS studies
- Molecules with rescue effects in all considered organisms, FDA-approved, already suitable for human