NCX1 is a novel target gene for hypoxia-inducible factor-1 in ischemic brain preconditioning.

The sodium-calcium exchanger-1 (NCX1) represents a key mediator for maintaining [Na(+)](i) and [Ca(2+)](i) homeostasis. Although changes in NCX1 protein and transcript expression have been detected during stroke, its transcriptional regulation is still unknown. Thus far, however, there is evidence that hypoxia-inducible factor-1 (HIF-1) is a nuclear factor required for transcriptional activation of several genes implicated in stroke. The main objective of this study was to investigate whether NCX1 gene might be a novel target of HIF-1 in the brain. Here we report that: (1) in neuronal cells, NCX1 increased expression after oxygen and glucose deprivation or cobalt-induced HIF-1 activation was prevented by silencing HIF-1; (2) the brain NCX1 promoter cloned upstream of the firefly-luciferase gene contained 2 regions of HIF-1 target genes called hypoxia-responsive elements that are sensitive to oxygen and glucose deprivation or cobalt chloride; (3) HIF-1 specifically bound hypoxia-responsive elements on brain NCX1, as demonstrated by band-shift and chromatin immunoprecipitation assays; (4) HIF-1α silencing prevented NCX1 upregulation and neuroprotection induced by ischemic preconditioning; and (5) NCX1 silencing partially reverted the preconditioning-induced neuroprotection in rats. NCX1 gene is a novel HIF-1 target, and HIF-1 exerts its prosurvival role through NCX1 upregulation during brain preconditioning.

Citation

Valeria Valsecchi, Giuseppe Pignataro, Annalisa Del Prete, Rossana Sirabella, Carmela Matrone, Francesca Boscia, Antonella Scorziello, Maria Josè Sisalli, Elga Esposito, Nicola Zambrano, Gianfranco Di Renzo, Lucio Annunziato. NCX1 is a novel target gene for hypoxia-inducible factor-1 in ischemic brain preconditioning. Stroke; a journal of cerebral circulation. 2011 Mar;42(3):754-63

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PMID: 21293012

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