Hypoxic adaptation engages the CBP/CREST-induced coactivator complex of Creb-HIF-1α in transactivating murine neuroblastic glucose transporter

Shanthie Thamotharan, Nupur Raychaudhuri, Masatoshi Tomi, Bo Chul Shin, Sherin U. Devaskar

研究成果: Article査読

10 被引用数 (Scopus)

抄録

We have shown in vitro a hypoxia-induced time-dependent increase in facilitative glucose transporter isoform 3 (GLUT3) expression in N2A murine neuroblasts. This increase in GLUT3 expression is partially reliant on a transcriptional increase noted in actinomycin D and cycloheximide pretreatment experiments. Transient transfection assays in N2A neuroblasts using murine glut3-luciferase reporter constructs mapped the hypoxia-induced enhancer activities to -857- to -573-bp and -203- to -177-bp regions. Hypoxia-exposed N2A nuclear extracts demonstrated an increase in HIF-1α and p-Creb binding to HRE (-828 to -824 bp) and AP-1 (-187 to -180 bp) cis-elements, respectively, in electromobility shift and supershift assays, which was confirmed by chromatin immunoprecipitation assays. In addition, the interaction of CBP with Creb and HIF-1α and CREST with CBP in hypoxia was detected by coimmunoprecipitation. Furthermore, small interference (si)RNA targeting Creb in these cells decreased endogenous Creb concentrations that reduced by twofold hypoxia-induced glut3 gene transcription. Thus, in N2A neuroblasts, phosphorylated HIF-1α and Creb mediated the hypoxia-induced increase in glut3 transcription. Coactivation by the Ca++-dependent CREST and CBP proteins may enhance cross-talk between p-Creb-AP-1 and HIF-1α/HRE of the glut3 gene. Collectively, these processes can facilitate an adaptive response to hypoxic energy depletion targeted at enhancing glucose transport and minimizing injury while fueling the proliferative potential of neuroblasts.

本文言語English
ページ(範囲)E583-E598
ジャーナルAmerican Journal of Physiology - Endocrinology and Metabolism
304
6
DOI
出版ステータスPublished - 2013
外部発表はい

ASJC Scopus subject areas

  • 内分泌学、糖尿病および代謝内科学
  • 生理学
  • 生理学(医学)

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