Primary and secondary drug screening assays for Friedreich ataxia

J Biomol Screen. 2012 Mar;17(3):303-13. doi: 10.1177/1087057111427949. Epub 2011 Nov 15.

Abstract

Friedreich ataxia (FRDA) is an autosomal recessive neuro- and cardiodegenerative disorder for which there are no proven effective treatments. FRDA is caused by decreased expression and/or function of the protein frataxin. Frataxin chaperones iron in the mitochondrial matrix for the assembly of iron-sulfur clusters (ISCs), which are prosthetic groups critical for the function of the Krebs cycle and the mitochondrial electron transport chain (ETC). Decreased expression of frataxin or the yeast frataxin orthologue, Yfh1p, is associated with decreased ISC assembly, mitochondrial iron accumulation, and increased oxidative stress, all of which contribute to mitochondrial dysfunction. Using yeast depleted of Yfh1p, a high-throughput screening (HTS) assay was developed in which mitochondrial function was monitored by reduction of the tetrazolium dye WST-1 in a growth medium with a respiration-only carbon source. Of 101 200 compounds screened, 302 were identified that effectively rescue mitochondrial function. To confirm activities in mammalian cells and begin understanding mechanisms of action, secondary screening assays were developed using murine C2C12 cells and yeast mutants lacking specific complexes of the ETC, respectively. The compounds identified in this study have potential relevance for other neurodegenerative disorders associated with mitochondrial dysfunction, such as Parkinson disease.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Cell Line
  • Drug Evaluation, Preclinical / methods*
  • Frataxin
  • Friedreich Ataxia / drug therapy
  • Friedreich Ataxia / metabolism*
  • High-Throughput Screening Assays / methods*
  • Iron-Binding Proteins / genetics*
  • Iron-Binding Proteins / metabolism
  • Iron-Sulfur Proteins / metabolism
  • Mice
  • Mitochondria / metabolism
  • Mitochondrial Diseases / genetics
  • Oxidative Stress / drug effects
  • Saccharomyces cerevisiae / genetics
  • Saccharomyces cerevisiae / metabolism
  • Tetrazolium Salts / chemistry
  • Tetrazolium Salts / metabolism

Substances

  • 2-(4-iodophenyl)-3-(4-nitrophenyl)-5-(2,4-disulfophenyl)-2H-tetrazolium
  • Iron-Binding Proteins
  • Iron-Sulfur Proteins
  • Tetrazolium Salts