title: Osteopontin inhibits HIF-2α mRNA expression in osteoarthritic chondrocytes.
abstract: The aim of the present study was to investigate thein vitroeffect of osteopontin (OPN) on the expression of hypoxia-inducible factor-2α (HIF-2α) in chondrocytes and the role of OPN in osteoarthritis (OA). Cartilage was purified from the tibial surfaces of patients with OA of the knee and culturedin vitroto obtain chondrocytes. Recombinant human OPN (rhOPN) and OPN small interfering RNA (siRNA) were used to treat the chondrocytes, and the changes in the expression levels of the HIF-2α gene were measured. An anti-CD44 blocking monoclonal antibody (mAb) was used to determine the probable ligand-receptor interactions. Reverse transcription-quantitative polymerase chain reaction assays were designed and validated with SYBR® Green dyes for the simultaneous quantiﬁcation of the mRNA expression levels of OPN and HIF-2α. The mRNA expression level of HIF-2α was markedly decreased in the rhOPN-treated group compared with that in the control group; by contrast, OPN siRNA increased HIF-2α gene expression. CD44 blocking mAb suppressed the inhibitory effect of OPN on HIF-2α mRNA expression. The results of the present study suggest that OPN may play a protective role in OA by inhibiting HIF-2α gene expression in osteoarthritic chondrocytes through CD44 interaction.
authors.affiliation: Department of Orthopaedics, Xiangya Hospital, Central South University, Changsha, Hunan, 410008, P.R. China.
authors.forename: Chao
authors.initials: C
authors.lastname: Cheng
authors.affiliation: Department of Orthopaedics, Xiangya Hospital, Central South University, Changsha, Hunan, 410008, P.R. China.
authors.forename: Fang-Jie
authors.initials: FJ
authors.lastname: Zhang
authors.affiliation: Department of Orthopaedics, Xiangya Hospital, Central South University, Changsha, Hunan, 410008, P.R. China.
authors.forename: Jian
authors.initials: J
authors.lastname: Tian
authors.affiliation: Department of Orthopaedics, Xiangya Hospital, Central South University, Changsha, Hunan, 410008, P.R. China.
authors.forename: Min
authors.initials: M
authors.lastname: Tu
authors.affiliation: Department of Orthopaedics, Xiangya Hospital, Central South University, Changsha, Hunan, 410008, P.R. China.
authors.forename: Yi-Lin
authors.initials: YL
authors.lastname: Xiong
authors.affiliation: Department of Orthopaedics, Xiangya Hospital, Central South University, Changsha, Hunan, 410008, P.R. China.
authors.forename: Wei
authors.initials: W
authors.lastname: Luo
authors.affiliation: Department of Orthopaedics, Xiangya Hospital, Central South University, Changsha, Hunan, 410008, P.R. China.
authors.forename: Yu-Sheng
authors.initials: YS
authors.lastname: Li
authors.affiliation: Hunan Province Environmental Monitoring Center, Changsha, Hunan 410019, P.R. China.
authors.forename: Bing-Bing
authors.initials: BB
authors.lastname: Song
authors.affiliation: Department of Orthopaedics, Xiangya Hospital, Central South University, Changsha, Hunan, 410008, P.R. China ; Orthopaedics Institute of Central South University, Changsha, Hunan 410008, P.R. China.
authors.forename: Shu-Guang
authors.initials: SG
authors.lastname: Gao
authors.affiliation: Department of Orthopaedics, Xiangya Hospital, Central South University, Changsha, Hunan, 410008, P.R. China ; Orthopaedics Institute of Central South University, Changsha, Hunan 410008, P.R. China.
authors.forename: Guang-Hua
authors.initials: GH
authors.lastname: Lei
keywords: CD44; HIF-2α; chondrocyte; osteoarthritis; osteopontin