Differentially regulated genes in HtrA2 knockout MEFs upon rotenone treatment

Cellular stress responses can be activated following functional defects in organelles such as mitochondria and the endoplasmic reticulum. Mitochondrial dysfunction caused by loss of the serine protease HtrA2 leads to a progressive movement disorder in mice and has been linked to parkinsonian neurodegeneration in humans. Here we demonstrate that loss of HtrA2 results in transcriptional up-regulation of nuclear genes characteristic of the integrated stress response, including the transcription factor CHOP, selectively in the brain. We also show that loss of HtrA2 results in the accumulation of unfolded proteins in the mitochondria, defective mitochondrial respiration and enhanced production of reactive oxygen species that contribute to the induction of CHOP expression and to neuronal cell death. CHOP expression is also significantly increased in Parkinson’s disease patients’ brain tissue. We therefore propose that this brain-specific transcriptional response to stress may be important in the advance of neurodegenerative diseases. Keywords: stress response to rotenone treatment This experiment was set out to identify genes that are differentially regulated upon rotenone treatment in HtrA2 knockout (KO) mouse embryonic fibroblasts (MEFs) compared to wild type (WT) MEFs. Primary MEFs were isolated and at passage 4 subjected to treatment with vehicle (control) or 1 μM rotenone (rot) for 4 hrs. 3 replicates were performed. RNA was isolated and samples were processed for hybridisation (12 samples in total).