title: Tumor necrosis factor alpha promotes the proliferation of human nucleus pulposus cells via nuclear factor-κB, c-Jun N-terminal kinase, and p38 mitogen-activated protein kinase.
abstract: Although tumor necrosis factor alpha (TNF-α) is known to play a critical role in intervertebral disc (IVD) degeneration, the effect of TNF-α on nucleus pulposus (NP) cells has not yet been elucidated. The aim of this study was to explore the effect of TNF-α on proliferation of human NP cells. NP cells were treated with different concentrations of TNF-α. Cell proliferation was determined by cell counting kit-8 (CCK-8) analysis and Ki67 immunofluorescence staining, and expression of cyclin B1 was studied by quantitative real-time RT-PCR. Cell cycle was measured by flow cytometry and cell apoptosis was analyzed using an Annexin V-fluorescein isothiocyanate (FITC) & propidium iodide (PI) apoptosis detection kit. To identify the mechanism by which TNF-α induced proliferation of NP cells, selective inhibitors of major signaling pathways were used and Western blotting was carried out. Treatment with TNF-α increased cell viability (as determined by CCK-8 analysis) and expression of cyclin B1 and the number of Ki67-positive and S-phase NP cells, indicating enhancement of proliferation. Consistent with this, NP cell apoptosis was suppressed by TNF-α treatment. Moreover, inhibition of NF-κB, c-Jun N-terminal kinase (JNK), and p38 mitogen-activated protein kinase (MAPK) blocked TNF-α-stimulated proliferation of NP cells. In conclusion, the current findings suggest that the effect of TNF-α on IVD degeneration involves promotion of the proliferation of human NP cells via the NF-κB, JNK, and p38 MAPK pathways.
authors.affiliation: Medical School of Southeast University, Nanjing 210009, Jiangsu, China.
authors.forename: Xiao-Hu
authors.initials: XH
authors.lastname: Wang
authors.affiliation: Department of Orthopaedics, Zhongda Hospital, Southeast University, Nanjing 210009, Jiangsu, China.
authors.forename: Xin
authors.initials: X
authors.lastname: Hong
authors.affiliation: Department of Orthopaedics, Zhongda Hospital, Southeast University, Nanjing 210009, Jiangsu, China.
authors.forename: Lei
authors.initials: L
authors.lastname: Zhu
authors.affiliation: Department of Orthopaedics, Zhongda Hospital, Southeast University, Nanjing 210009, Jiangsu, China.
authors.forename: Yun-Tao
authors.initials: YT
authors.lastname: Wang
authors.affiliation: Department of Orthopaedics, Zhongda Hospital, Southeast University, Nanjing 210009, Jiangsu, China.
authors.forename: Jun-Ping
authors.initials: JP
authors.lastname: Bao
authors.affiliation: Department of Surgery, Klinikum rechts der Isar, Technische Universität München, Munich D-81675, Germany.
authors.forename: Lei
authors.initials: L
authors.lastname: Liu
authors.affiliation: Department of Orthopaedics, Zhongda Hospital, Southeast University, Nanjing 210009, Jiangsu, China.
authors.forename: Feng
authors.initials: F
authors.lastname: Wang
authors.affiliation: Medical School of Southeast University, Nanjing 210009, Jiangsu, China Department of Orthopaedics, Zhongda Hospital, Southeast University, Nanjing 210009, Jiangsu, China wuxiaotao@medmail.com.cn.
authors.forename: Xiao-Tao
authors.initials: XT
authors.lastname: Wu
mesh_terms: D017209:Apoptosis / Q000187:drug effects / Q000502:physiology; D002453:Cell Cycle / Q000187:drug effects / Q000502:physiology; D049109:Cell Proliferation / Q000187:drug effects* / Q000502:physiology; D002478:Cells, Cultured; D056744:Cyclin B1 / Q000378:metabolism; D004305:Dose-Response Relationship, Drug; D006801:Humans; D007403:Intervertebral Disc / Q000166:cytology* / Q000187:drug effects / Q000502:physiology; D048031:JNK Mitogen-Activated Protein Kinases / Q000502:physiology*; D020935:MAP Kinase Signaling System / Q000187:drug effects / Q000502:physiology; D016328:NF-kappa B / Q000502:physiology*; D015398:Signal Transduction / Q000187:drug effects / Q000502:physiology; D014409:Tumor Necrosis Factor-alpha / Q000494:pharmacology*; D048051:p38 Mitogen-Activated Protein Kinases / Q000502:physiology*
chemical_list: D056744:Cyclin B1; D016328:NF-kappa B; D014409:Tumor Necrosis Factor-alpha; D048031:JNK Mitogen-Activated Protein Kinases; D048051:p38 Mitogen-Activated Protein Kinases
keywords: Tumor necrosis factor alpha; intervertebral disc degeneration; mitogen-activated protein kinase; nuclear factor-κB; nucleus pulposus cell; proliferation