title: Hypoxia-regulated neurotrophin-3 expression by multicopy hypoxia response             elements reduces apoptosis in PC12 cells.
abstract: We have previously reported that 5 copies of the hypoxia response element             (HRE) can conditionally regulate brain-derived neurotrophic factor gene expression             under hypoxic/ischemic conditions in mice. In the present study, we investigated             the controlled expression of neurotrophin-3 (NT-3) by HRE under hypoxic conditions             and determined the protective effects of conditionally expressed NT-3 on hypoxia-induced             apoptosis in PC12 cells. Five copies of the HRE (5HRE) and the simian virus 40             minimal promoter (SV40mp) were employed to construct a cassette, and transfer             of therapeutic gene, NT-3, into PC12 cells was achieved using a retroviral vector.             Our results showed that the retroviral vector, pLNC-5HRE-NT3, was successfully             constructed and transfected into PC12 cells. Compared with normal conditions,             in which NT-3 was expressed at low levels, the expression of NT-3 significantly             increased under hypoxic conditions in 5HRE-NT3 transgenic PC12 cells (P<0.05).             By contrast, in NT-3 transgenic PC12 cells without HRE, we found no significant             difference in NT-3 expression between the normoxic and hypoxic groups. The conditional             adjustment of NT-3 expression by 5HRE significantly reduced apoptosis induced             by hypoxia in 5HRE-NT3 transgenic PC12 cells (P<0.05) but not in 5HRE-enhanced             green fluorescent protein (EGFP) transgenic PC12 cells and PC12 cells without             gene transfer. In addition, the hypoxia-induced upregulation of both p38 and caspase-3             activities was suppressed in 5HRE-NT3 transgenic PC12 cells under hypoxic conditions             (P<0.05). Taken together, these results demonstrate that 5HRE-SV40mp regulates             NT-3 gene expression in response to hypoxia in PC12 cells. The data presented             in this study may prove useful in future gene therapy studies for the treatment             of ischemic diseases.
authors.affiliation: Institute of Neurobiology, Environment and Genes Related to Diseases Key Laboratory of Education Ministry, Xi'an Jiaotong University College of Medicine, Xi'an, Shaanxi 710061, PR China.
authors.forename: Junfeng
authors.initials: J
authors.lastname: Zhang
authors.forename: Qindong
authors.initials: Q
authors.lastname: Shi
authors.forename: Xinlin
authors.initials: X
authors.lastname: Chen
authors.forename: Pengbo
authors.initials: P
authors.lastname: Yang
authors.forename: Cunfang
authors.initials: C
authors.lastname: Qi
authors.forename: Jianshui
authors.initials: J
authors.lastname: Zhang
authors.forename: Haixia
authors.initials: H
authors.lastname: Lu
authors.forename: Jianxin
authors.initials: J
authors.lastname: Liu
authors.forename: Qian
authors.initials: Q
authors.lastname: Jiao
authors.forename: Lingyu
authors.initials: L
authors.lastname: Zhao
authors.forename: Bingqiao
authors.initials: B
authors.lastname: Zhao
authors.forename: Ping
authors.initials: P
authors.lastname: Zheng
authors.forename: Yong
authors.initials: Y
authors.lastname: Liu
mesh_terms: D000818:Animals; D017209:Apoptosis; D053148:Caspase 3 / Q000378:metabolism; D015687:Cell Hypoxia; D056915:DNA Copy Number Variations; D005786:Gene Expression Regulation; D015316:Genetic Therapy; D049452:Green Fluorescent Proteins / Q000096:biosynthesis / Q000235:genetics; D020933:Neurotrophin 3 / Q000235:genetics* / Q000378:metabolism; D016716:PC12 Cells; D051381:Rats; D011994:Recombinant Proteins / Q000235:genetics / Q000378:metabolism; D020218:Response Elements; D015854:Up-Regulation; D048051:p38 Mitogen-Activated Protein Kinases / Q000378:metabolism
chemical_list: D020933:Neurotrophin 3; D011994:Recombinant Proteins; C485184:enhanced green fluorescent protein; D049452:Green Fluorescent Proteins; D048051:p38 Mitogen-Activated Protein Kinases; C505410:Casp3 protein, rat; D053148:Caspase 3