Caijun Liu1,2, Hao Yang3, Fei Gao4, Xiang Li5, Yan An3, Jianru Wang6, Anmin Jin1. 1. Department of Orthopaedics, Zhujiang Hospital, Southern Medical University, Guangzhou, China. 2. Department of Orthopaedics, Affiliated Orthopaedics and Trauma Hospital, Guangzhou University of Chinese Medicine, Guangzhou, China. 3. Department of Spine Surgery, Beijing Jishuitan Hospital, Peking University, Beijing, China. 4. Department of Orthopaedic Surgery, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China. 5. Department of Orthopaedics, Huangyan Hospital Affiliated to Wenzhou Medical University, Taizhou, China. 6. Department of Spine Surgery, The First Affiliated Hospital of Sun Yat-sen University, Guangzhou, China.
Abstract
STUDY DESIGN: Rat nucleus pulposus (NP) cells were activated with resistin with or without p38 mitogen-activated protein kinase (MAPK) pathway inhibition. The expression of a disintegrin and metalloprotease with thrombospondin motif-5 (ADAMTS-5), which plays an important role in intervertebral disc degeneration (IDD), was determined. OBJECTIVE: The aim of this study was to demonstrate whether resistin can influence the ADAMTS-5 expression and to further investigate the underlying mechanisms. SUMMARY OF BACKGROUND DATA: Obesity has been demonstrated to promote IDD, whereas the exact mechanism remains poorly understood. Resistin, as an important adipokine, is increased with obesity and has been shown to play pro-inflammatory and catabolic role in cartilage metabolism. However, the effect of resistin on the catabolic enzymes within NP cells remains unknown. METHODS: We exposed NP cells to resistin, and the transcriptional activity, gene expression, and protein levels of ADAMTS-5 were measured by luciferase reporter assay, qRT-polymerase chain reaction, immunofluorescence, and western blot, respectively. The activation of p38 MAPK pathways was detected using western blot analysis. RESULTS: Resistin had no effect on cell viability. Resistin increased ADAMTS-5 expression in rat NP cells time and dose dependently. The p38 MAPK signaling pathway was activated after exposure to resistin. Treatment with p38 inhibitor decreased the upregulation of ADAMTS-5 by resistin. CONCLUSION: The current study, for the first time, investigated the role of resistin in ADAMTS-5 regulation in IDD. These findings provide novel evidence supporting the causative role of obesity in IDD, which is important to develop novel preventative or therapeutic treatment in disc degenerative disorders. LEVEL OF EVIDENCE: N/A.
STUDY DESIGN:Rat nucleus pulposus (NP) cells were activated with resistin with or without p38 mitogen-activated protein kinase (MAPK) pathway inhibition. The expression of a disintegrin and metalloprotease with thrombospondin motif-5 (ADAMTS-5), which plays an important role in intervertebral disc degeneration (IDD), was determined. OBJECTIVE: The aim of this study was to demonstrate whether resistin can influence the ADAMTS-5 expression and to further investigate the underlying mechanisms. SUMMARY OF BACKGROUND DATA: Obesity has been demonstrated to promote IDD, whereas the exact mechanism remains poorly understood. Resistin, as an important adipokine, is increased with obesity and has been shown to play pro-inflammatory and catabolic role in cartilage metabolism. However, the effect of resistin on the catabolic enzymes within NP cells remains unknown. METHODS: We exposed NP cells to resistin, and the transcriptional activity, gene expression, and protein levels of ADAMTS-5 were measured by luciferase reporter assay, qRT-polymerase chain reaction, immunofluorescence, and western blot, respectively. The activation of p38 MAPK pathways was detected using western blot analysis. RESULTS: Resistin had no effect on cell viability. Resistin increased ADAMTS-5 expression in rat NP cells time and dose dependently. The p38 MAPK signaling pathway was activated after exposure to resistin. Treatment with p38 inhibitor decreased the upregulation of ADAMTS-5 by resistin. CONCLUSION: The current study, for the first time, investigated the role of resistin in ADAMTS-5 regulation in IDD. These findings provide novel evidence supporting the causative role of obesity in IDD, which is important to develop novel preventative or therapeutic treatment in disc degenerative disorders. LEVEL OF EVIDENCE: N/A.