Transcriptional profiling of mouse embryonic fibroblasts harboring the Fxn G127V mutation

Friedreich's ataxia (FRDA) is a neurodegenerative disease caused by mutations in the frataxin (FXN) gene. In this study, we immortalized mouse embryonic fibroblasts (MEFs) derived from G127V Fxn mutant mice and compared them to the wild-type (WT) MEFs. Mutant G127V MEFs demonstrated decreased cell proliferation and ATP production, as well as an increase in reactive oxygen species (ROS) production when compared to WT cells. These phenotypes are partially corrected by exogenous expression of frataxin. Surprisingly, extended passaging of immortalized G127V Fxn MEFs improves their proliferation, and alleviates ATP deficiency as well as decreases ROS levels despite persistent frataxin deficiency. We defined gene expression changes associated with phenotypic adaptation of G127V mutant MEFs by comparing transcriptional profiles of early and late passage G127V MEFs with WT cells. To investigate the molecular mechanisms underlying phenotypic adaptation associated with extended passages of immortalized mutant G127V MEFs, we purified RNA from WT (passage 8, WT17_P8 and WT18_P8), early passage mutant G127V (passage 6, Mut4Z_P6 and passage 9, Mut3J_P9) and late passage G127V (passage 19, Mut4Z_P19 and passage 26, Mut3J_P26) MEFs. The extracted total RNAs from each sample were processed for transcriptome sequencing.