Role of the telomeric factor TRF2 in post-hypoxic brain damages.

The neuronal excitotoxicity that follows reoxygenation after a hypoxic period may contribute to epilepsy, Alzheimer's disease, Parkinson's disease and various disorders that are related to inadequate supplement of oxygen in neurons. Therefore, counteracting the deleterious effects of post-hypoxic stress is an interesting strategy to treat a large spectrum of neurodegenerative diseases. Here, we show that the expression of the key telomere protecting protein Trf2 decreases in the brain of mice submitted to a post-hypoxic stress. Moreover, downregulating the expression of Terf2 in hippocampal neural cells of unchallenged mice triggers an excitotoxicity-like phenotype including glutamate overexpression and behavioral alterations while overexpressing Terf2 in hippocampal neural cells of mice subjected to a post-hypoxic treatment prevents brain damages. Moreover, Terf2 overexpression in culture neurons counteracts the oxidative stress triggered by glutamate. Finally, we provide evidence that the effect of Terf2 downregulation on excitotoxicity involves Sirt3 repression leading to mitochondrial dysfunction. We propose that increasing the level of Terf2 expression is a potential strategy to reduce post-hypoxic stress damages.