title: Up-Regulation of Neuronal Nitric Oxide Synthase Expression by Cobalt Chloride Through a HIF-1α Mechanism in Neuroblastoma Cells.
abstract: Nitric oxide (NO) plays a dual role in response to neural hypoxia. NO is synthesized by three isoforms of nitric oxide synthase (NOS), among which the neuronal NOS (nNOS) is predominant in the nervous system. Hypoxia-inducible factor-1α (HIF-1α) is a transcription factor that is induced under hypoxic conditions, but its correlation with nNOS remains unclear. In the present study, we aimed at clarifying the regulation pattern of the nNOS expression in response to cobalt chloride (CoCl2), a widely used chemical mimic of hypoxia, and the role of HIF-1α in this process in neuroblastoma cells. We found CoCl2 evidently increased the nNOS expression and NO production in human neuroblastoma SK-N-SH cells, but the effect of CoCl2 on NO was partially abrogated by 7-nitroindazole, a selective inhibitor for nNOS. Importantly, we identified a hypoxia response element (HRE) within the nNOS promoter, to which HIF-1α may bind, and CoCl2 greatly enhanced the HIF-1α expression and its binding to the HRE. Meanwhile, we demonstrated that this HRE was functionally important for the activation of the nNOS transcription, and CoCl2 increased the transcriptional activity of the nNOS promoter through this HRE. Taken together, our study shows that CoCl2 may induce the nNOS expression and NO production through a HIF-1α mechanism in neuroblastoma cells, which may provide a potential target for the treatment of neurological hypoxic disorders caused by NO dysregulation.
authors.affiliation: Department of Neurosurgery, The First Affiliated Hospital, China Medical University, No. 155, Nanjing Street, Heping District, Shenyang, 110001, People's Republic of China. tyjk1972@163.com.
authors.forename: Guangyu
authors.initials: G
authors.lastname: Li
authors.affiliation: Department of Medical Genetics, College of Basic Medical Science, China Medical University, No. 92, Bei Er Road, Heping District, Shenyang, 110001, People's Republic of China. yyzhao@mail.cmu.edu.cn.
authors.forename: Yanyan
authors.initials: Y
authors.lastname: Zhao
authors.affiliation: Department of Medical Genetics, College of Basic Medical Science, China Medical University, No. 92, Bei Er Road, Heping District, Shenyang, 110001, People's Republic of China.
authors.forename: Yinghui
authors.initials: Y
authors.lastname: Li
authors.affiliation: Department of Medical Genetics, College of Basic Medical Science, China Medical University, No. 92, Bei Er Road, Heping District, Shenyang, 110001, People's Republic of China.
authors.forename: Jingyu
authors.initials: J
authors.lastname: Lu
mesh_terms: D015687:Cell Hypoxia; D045744:Cell Line, Tumor; D047369:Chromatin Immunoprecipitation; D003035:Cobalt / Q000494:pharmacology*; D015972:Gene Expression Regulation, Neoplastic / Q000187:drug effects*; D017930:Genes, Reporter; D006801:Humans; D051795:Hypoxia-Inducible Factor 1, alpha Subunit / Q000096:biosynthesis / Q000235:genetics / Q000502:physiology*; D016297:Mutagenesis, Site-Directed; D009363:Neoplasm Proteins / Q000096:biosynthesis* / Q000235:genetics; D009447:Neuroblastoma / Q000473:pathology; D009569:Nitric Oxide / Q000378:metabolism; D052248:Nitric Oxide Synthase Type I / Q000096:biosynthesis* / Q000235:genetics; D011401:Promoter Regions, Genetic / Q000235:genetics*; D012333:RNA, Messenger / Q000096:biosynthesis / Q000235:genetics; D012334:RNA, Neoplasm / Q000096:biosynthesis / Q000235:genetics; D020218:Response Elements / Q000235:genetics*; D014158:Transcription, Genetic / Q000187:drug effects; D014162:Transfection; D015854:Up-Regulation / Q000187:drug effects
chemical_list: C497442:HIF1A protein, human; D051795:Hypoxia-Inducible Factor 1, alpha Subunit; D009363:Neoplasm Proteins; D012333:RNA, Messenger; D012334:RNA, Neoplasm; D009569:Nitric Oxide; D003035:Cobalt; C496320:NOS1 protein, human; D052248:Nitric Oxide Synthase Type I; C018021:cobaltous chloride
keywords: HIF-1α; Hypoxia; Nervous system; nNOS