CoCl2-induced expression of p300 promotes neuronal-like PC12 cell damage

Hypoxia inducible factor-1 (HIF-1) is an important transcription activator involved in cell responses to hypoxic stress. Previous studies demonstrated that HIF-1 exerts both pro- and anti-survival effects under hypoxia. The mechanisms underlying these contrary effects of HIF-1 remain unclear. Transcription co-activator p300 is necessary for HIF-1-induced transcriptional activation. Many factors inhibit HIF-1 activity by competitively binding to p300, which suggests that p300 is a key player in the modulation of HIF-1 function. To examine the alteration of p300 expression under hypoxia and its role in hypoxia-induced neuronal damage, neuronal-like PC12 cells were cultured with cobalt chloride (CoCl2), a hypoxia mimic reagent. The results showed that CoCl2 treatment-induced p300 expression along with an increase in cell damage. Furthermore, CoCl2-induced cell damage was attenuated by suppression of p300 expression with short hairpin RNA (shRNA). The data suggests that CoCl2-induced up-regulation of p300 expression promotes neuronal-like PC12 cell damage.