Over-Expressing Prohibitin (PHB) in Neuronal Cultures Exacerbates Cell Death Following Hydrogen Peroxide and L-Glutamic Acid Induced Injury

Using proteomics, previous work in our laboratory identified five mitochondrial related proteins [citrate synthase (CS), glucose-regulated protein 75 (GRP75), heat shock protein 60 (HSP60), prohibitin (PHB), voltage-dependent anion channel 1 (VDAC1)] to be differentially expressed in primary cortical neuronal cultures following preconditioning treatments [1] [2]. To investigate a protective or damaging role of these five proteins in neurons, we used RNAi constructs to knockdown and adenoviral vectors to over-express the proteins in cortical neuronal cultures prior to exposure to three ischemia-related injury models: excitotoxicity (L-glutamic acid), oxidative stress (hydrogen peroxide) and in vitro ischemia (oxygen-glucose deprivation). We observed that down-regulating these mitochondrial proteins had no effect on neuronal viability, in any injury model. By contrast, over-expression of PHB exacerbated cell death in the hydrogen peroxide and L-glutamic acid injury models. These findings indicate that PHB plays a neurodamaging role following oxidative and excitotoxic stress and suggests that the protein is a potential therapeutic target for the design of drugs to limit neuronal death following cerebral ischemia and other forms of brain injury.