title: Discordant mRNA and protein expression of CXCR4 under in vitro CoCl2-induced hypoxic conditions.
abstract: Cobalt chloride (CoCl2) has long been accepted as a suitable in vitro hypoxia-mimetic agent. The gene CXCR4, which encodes a chemokine receptor, plays a key role in hypoxic retinal disease. Here, we investigated the mRNA and protein expression of CXCR4 in WERI-Rb1 retinoblastoma cells and human umbilical vein endothelial cells (HUVECs) under CoCl2-induced hypoxic conditions, by means of real-time PCR and western blot. We found that CoCl2-induced hypoxia profoundly increased CXCR4 expression at the mRNA level, but not at the protein level, at 12, 24, 48 and 72 h in these cells. Interestingly, this result differed from observations of 1% O2hypoxic conditions. Additionally, luciferase assays demonstrated that CoCl2-induced hypoxia significantly increased transcription at the CXCR4 promoter. In order to compare our in vitro findings with the effects of hypoxia in vivo, an OIR (Oxygen-induced retinopathy) rat model was constructed. However, both CXCR4 mRNA and protein levels in OIR rats were significantly increased compared to controls. Thus taken together, our findings suggest that the relationship between CXCR4 mRNA and protein expression is not strictly linear under in vitro CoCl2-induced hypoxic conditions. through comparative in vitro and in vivo experiments, this study implies that CoCl2is an imperfect simulation of hypoxia in retinal disease.
authors.affiliation: State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-sen University, 510060, PR China.
authors.forename: Mingjun
authors.initials: M
authors.lastname: Tang
authors.affiliation: State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-sen University, 510060, PR China.
authors.forename: Ying
authors.initials: Y
authors.lastname: Yang
authors.affiliation: State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-sen University, 510060, PR China.
authors.forename: Jingzhi
authors.initials: J
authors.lastname: Yu
authors.affiliation: State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-sen University, 510060, PR China.
authors.forename: Nandan
authors.initials: N
authors.lastname: Wu
authors.affiliation: State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-sen University, 510060, PR China.
authors.forename: Pei
authors.initials: P
authors.lastname: Chen
authors.affiliation: State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-sen University, 510060, PR China.
authors.forename: Lijun
authors.initials: L
authors.lastname: Xu
authors.affiliation: State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-sen University, 510060, PR China.
authors.forename: Qiyun
authors.initials: Q
authors.lastname: Wang
authors.affiliation: State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-sen University, 510060, PR China.
authors.forename: Zhuojun
authors.initials: Z
authors.lastname: Xu
authors.affiliation: State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-sen University, 510060, PR China.
authors.forename: Jian
authors.initials: J
authors.lastname: Ge
authors.affiliation: State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-sen University, 510060, PR China.
authors.forename: Keming
authors.initials: K
authors.lastname: Yu
authors.affiliation: State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-sen University, 510060, PR China. Electronic address: zhuangj@mail.sysu.edu.cn.
authors.forename: Jing
authors.initials: J
authors.lastname: Zhuang
mesh_terms: D000818:Animals; D015687:Cell Hypoxia; D045744:Cell Line, Tumor; D003035:Cobalt / Q000494:pharmacology*; D061307:Human Umbilical Vein Endothelial Cells; D006801:Humans; D012333:RNA, Messenger / Q000378:metabolism*; D051381:Rats; D019718:Receptors, CXCR4 / Q000235:genetics / Q000378:metabolism*; D012164:Retinal Diseases / Q000378:metabolism; D015854:Up-Regulation
chemical_list: C527276:CXCR4 protein, human; D012333:RNA, Messenger; D019718:Receptors, CXCR4; D003035:Cobalt; C018021:cobaltous chloride
keywords: CXCR4; Cobalt chloride; Human umbilical vein endothelial cells; Retinal ischemia; Retinoblastoma