A yeast-based assay identifies drugs active against human mitochondrial disorders

Abstract

Due to the lack of relevant animal models, development of effective treatments for human mitochondrial diseases has been limited. Here we establish a rapid, yeast-based assay to screen for drugs active against human inherited mitochondrial diseases affecting ATP synthase, in particular NARP (neuropathy, ataxia, and retinitis pigmentosa) syndrome. This method is based on the conservation of mitochondrial function from yeast to human, on the unique ability of yeast to survive without production of ATP by oxidative phosphorylation, and on the amenability of the yeast mitochondrial genome to site-directed mutagenesis. Our method identifies chlorhexidine by screening a chemical library and oleate through a candidate approach. We show that these molecules rescue a number of phenotypes resulting from mutations affecting ATP synthase in yeast. These compounds are also active on human cybrid cells derived from NARP patients. These results validate our method as an effective high-throughput screening approach to identify drugs active in the treatment of human ATP synthase disorders and suggest that this type of method could be applied to other mitochondrial diseases.budding yeast | drug screening | transcription profiling | NARP cybrid

Expression of Nuclear and Mitochondrial Genes Encoding ATP Synthase Is Synchronized by Disassembly of a Multisynthetase Complex

“…A strong F 1 defect like the one observed in the nM strain normally leads to low contents in complexes III and IV (Couplan et al, 2011), which is believed to reflect a regulatory mechanism that balances the expression of ATP synthase and respiratory enzymes. In one such mutant (fmc1D), we found that most of the nuclear-encoded subunits of these complexes are poorly expressed (Couplan et al, 2011).…”

Chémobiologie à l’happy hour

“…(Figure 2). De façon remarquable, ces deux molécules sont également actives de façon dépendante de la dose et à des concentrations de l'ordre de quelques dizaines à centaines de nM, validant ainsi définitivement nos modèles de levures NARP [13]. Par ailleurs, ces modèles nous ont permis d'isoler des composés actifs spécifiquement sur les phénotypes associés à certaines mutations NARP, ouvrant ainsi la possibilité de rechercher des pistes thérapeutiques personnalisées.…”

“…Enfin, des approches de chémogénomique ont été entreprises chez la levure afin d'identifier les voies cellulaires ciblées par ces molécules, une information cruciale pour leur optimisation, mais aussi pour mieux comprendre les processus physiopathologiques impliqués dans ces maladies très complexes et hétérogènes. Comme d'aucuns pouvaient s'y attendre, les voies identifiées (complexe III et import mitochondrial) sont conservées de la levure à l'homme, dévoilant ainsi de nouvelles pistes thérapeutiques potentielles pour traiter des maladies mitochondriales [13,14].…”

The utility of yeast as a tool for cell-based, target-directed high-throughput screening

“…These data (Bach et al 2003(Bach et al , 2006Couplan et al 2011) show that for some processes, the conservation between yeast and the target organism is close enough to allow direct, informative screening against the model system. In addition, it is important to recognize that in all these cases of phenotypic rescue the possibility of generically toxic false positives is removed greatly simplifying the generation and interpretation of data.…”

“…This relates to a defect in the ATP synthase assembly and as such serves as an effective model for certain mitochondrial diseases e.g. NARP (neuropathy, ataxia and retinitis pigmentosa) (Couplan et al 2011). In their assay platform Couplan and colleagues used filters spotted with each compound to identify those that induced an enhanced halo of growth when placed on solid glycerol medium spread with the yeast strain of interest.…”