Journal Article

Preferential activation of HIF-2α adaptive signalling in neuronal-like cells in response to acute hypoxia

Poole, Amy V., Martín-Aragón Baudel, Miguel A. S., Darlison, Mark G., Rae, Mick T., Fraser, Jennifer A.

2017

Overview

Stroke causes severe neuronal damage as disrupted cerebral blood flow starves neurons of oxygen and glucose. The hypoxia inducible factors (HIF-1α and HIF-2α) orchestrate oxygen homeostasis and regulate specific aspects of hypoxic adaptation. Here we show the importance of HIF-2α dependant signalling in neuronal adaptation to hypoxic insult. PC12 and NT2 cells were differentiated into neuronal-like cells using NGF and retinoic acid, and exposed to acute hypoxia (1% O2). Gene and protein expression was analysed by qPCR and immunoblotting and the neuronal-like phenotype was examined. PC12 and NT2 differentiation promoted neurite extension and expression of neuronal markers, NSE and KCC2. Induction of HIF-1α mRNA or protein was not detected in hypoxic neuronal-like cells, however marked induction of HIF-2α mRNA and protein expression was observed. Induction of HIF-1α target genes was also not detected in response to acute hypoxia, however significant induction of HIF-2α transcriptional targets was clearly evident. Furthermore, hypoxic insult dramatically reduced both neurite number and length, and attenuated expression of neuronal markers, NSE and KCC2. This correlated with an increase in expression of the neural progenitor and stem cell-like markers, CD44 and vimentin, suggesting HIF-2α molecular mechanisms could potentially promote regression of neuronal-like cells to a stem-like state and trigger neuronal recovery following ischaemic insult. Our findings suggest the HIF-2α pathway predominates over HIF-1α signalling in neuronal-like cells following acute hypoxia.

• Publisher: Public Library of Science,Public Library of Science (PLoS)
• Subject: Adaptation / Adaptation, Physiological / Angiogenesis / Animals / Apoptosis / Basic Helix-Loop-Helix Transcription Factors - metabolism / Biology and Life Sciences / Biomarkers / Blood flow / CD44 antigen / Cell cycle / Cell Differentiation / Cell division / Cell Hypoxia / Cerebral blood flow / Differentiation / Endoplasmic Reticulum Stress / Gene expression / Growth factors / Homeostasis / Humans / Hypoxia / Hypoxia-inducible factor 1 / Hypoxia-inducible factor 1a / Immunoblotting / Ischemia / Medicine and Health Sciences / Molecular modelling / Nerve growth factor / Neural stem cells / Neural Stem Cells - metabolism / Neurogenesis / Neurons - cytology / Neurons - metabolism / Neurotrophin 2 / Oxygen / Penicillin / Potassium-chloride cotransporter / Protein Stability / Proteins / Rats / Real-Time Polymerase Chain Reaction / Regression analysis / Research and Analysis Methods / Retinoic acid / Rodents / Signal Transduction / Signaling / Stem cells / Stroke / Transcription / Veins & arteries / Vimentin