Down-regulation of interleukin 7 mRNA by hypoxia is calcium dependent

Aigang Lu, Joseph F. Clark, Ruiqiong Ran, Gail Pyne-Geithman, Kenneth R. Wagner, David E. Millhorn, Frank R Sharp

Research output: Contribution to journalArticle

1 Scopus citations

Abstract

Objective: The discovery of IL-7Rα polymorphisms implicated in the pathogenesis of multiple sclerosis has highlighted the importance of interleukin 7 (IL-7) in central nervous system diseases. Hypoxia affects neurological disease states in part by modulating expression of many early and late response genes. The present work used cultured PC12 cells to investigate the effect of hypoxia on IL-7 expression. Method: PC12 cells were cultured in Dulbecco's modified Eagle's medium (DMEM)/F12 medium. RNA was isolated and reverse transcriptase-polymerase chain reaction (RT-PCR) was run to quantify messenger RNA (mRNA) change. Western blots were used to assess IL-7 protein change in the medium. Extracellular free Ca2+ was removed by using Ca2+-free DMEM/F12 with 1 mM ethylene glycol tetraacetic acid for 45 minutes before the start of hypoxia. Results: Exposure of PC12 cells to 1% oxygen for 6 hours decreased IL-7 mRNA by 77% using RT-PCR (p<0.01). Exposure to 1% oxygen for 24 hours decreased IL-7 protein in the medium by 21% (p<0.05). As hypoxia duration increased (2, 4, 6 and 24 hours) or oxygen concentrations decreased (10%, 5% and 1%), IL-7 mRNA expression progressively decreased. Removal of extracellular free Ca2+ completely prevented these hypoxia-induced decreases of IL-7 mRNA. Discussion: Since IL-7 exhibits trophic properties in developing brain, down-regulation of IL-7 by hypoxia may contribute to hypoxia-induced injury to neural cells.

Original languageEnglish (US)
Pages (from-to)545-549
Number of pages5
JournalNeurological Research
Volume31
Issue number5
DOIs
StatePublished - Jun 2009

Keywords

  • Calcium
  • Cytokines
  • Hypoxia
  • Interleukin 7
  • PC12 cells

ASJC Scopus subject areas

  • Clinical Neurology
  • Neurology

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    Lu, A., Clark, J. F., Ran, R., Pyne-Geithman, G., Wagner, K. R., Millhorn, D. E., & Sharp, F. R. (2009). Down-regulation of interleukin 7 mRNA by hypoxia is calcium dependent. Neurological Research, 31(5), 545-549. https://doi.org/10.1179/174313209X380928