title: P120-Catenin Protects Endplate Chondrocytes From Intermittent Cyclic Mechanical Tension Induced Degeneration by Inhibiting the Expression of RhoA/ROCK-1 Signaling Pathway.
abstract: METHODS
  The changes of endplate chondrocytes induced by intermittent cyclic mechanical tension (ICMT) were observed by realtime reverse transcription-polymerase chain reaction, immunofluorescence, and Western blot analysis.
  
  
  OBJECTIVE
  To investigate the role of RhoA/ROCK-1 signaling pathway and E-cadherin/P120-catenin complex in endplate chondrocytes degeneration induced by ICMT.
  
  
  BACKGROUND
  ICMT can induce the endplate chondrocyte degeneration. However, the relationship between P120-catenin or RhoA/ROCK-1 signaling pathway and endplate chondrocytes degeneration induced by ICMT is not clear.
  
  
  METHODS
  ICMT (strain at 0.5 Hz sinusoidal curve at 8% elongation) was applied to rat endplate chondrocytes for 6 days, 16 hours a day. The cell viability and apoptosis were examined by the LIVE/DEAD assay and flow cytometry. Histological staining was used to examine the lumbar disc tissue morphology and extracellular matrix. To regulate RhoA/ROCK-1 signaling pathway and the expression of E-cadherin and P120-catenin, RhoA/ROCK-1 pathway-specific inhibitors, E-cadherin, and p120-catenin plasmid were applied. Coimmunoprecipitation was employed to examine the interaction between E-cadherin and P120-catenin, P120-catenin, and RhoA. The related gene expression and protein location was examined by realtime reverse transcription-polymerase chain reaction, Western blot, and immunofluorescence.
  
  
  RESULTS
  There was no change of viability verified by LIVE/DEAD assay and flow cytometry after ICMT loading. ICMT loading led to RhoA/ROCK-1 signaling activation and the loss of the chondrogenic phenotype of endplate chondrocytes. Inhibition of RhoA/ROCK-1 signaling pathway significantly ameliorated the degeneration induced by ICMT. The expression of P120-catenin and E-cadherin were inhibited by ICMT. ICMT reduced the interaction between P120-catenin and E-cadherin. Furthermore, over-expression of P120-catenin and E-cadherin can suppress the expression of chondrogenic gene, over-expression of P120-catenin can suppress the RhoA/ROCK-1 signaling pathway, but over-expression of E-cadherin cannot do it.
  
  
  CONCLUSIONS
  P120-catenin protects endplate chondrocytes from ICMT Induced degeneration by inhibiting the expression of RhoA/ROCK-1 signaling pathway.
  
  
  METHODS
  N/A.
authors.affiliation: Department of Spine Surgery, Yijishan Hospital, Wannan Medical College, Wuhu, Anhui, China.
authors.forename: Hong-Guang
authors.initials: HG
authors.lastname: Xu
authors.affiliation: Department of Spine Surgery, Yijishan Hospital, Wannan Medical College, Wuhu, Anhui, China.
authors.forename: Ming-Ming
authors.initials: MM
authors.lastname: Ma
authors.affiliation: Department of Orthopedic Surgery, The People's Hospital of Luan, Luan, Anhui, China.
authors.forename: Quan
authors.initials: Q
authors.lastname: Zheng
authors.affiliation: Department of Spine Surgery, Yijishan Hospital, Wannan Medical College, Wuhu, Anhui, China.
authors.forename: Xiang
authors.initials: X
authors.lastname: Shen
authors.affiliation: Department of Spine Surgery, Yijishan Hospital, Wannan Medical College, Wuhu, Anhui, China.
authors.forename: Hong
authors.initials: H
authors.lastname: Wang
authors.affiliation: Department of Spine Surgery, Yijishan Hospital, Wannan Medical College, Wuhu, Anhui, China.
authors.forename: Shu-Feng
authors.initials: SF
authors.lastname: Zhang
authors.affiliation: The Key Laboratory of Stem Cell Biology, Institute of Health Sciences, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences & Shanghai Jiao Tong University School of Medicine, China.
authors.forename: Jia-Jia
authors.initials: JJ
authors.lastname: Xu
authors.affiliation: The Key Laboratory of Stem Cell Biology, Institute of Health Sciences, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences & Shanghai Jiao Tong University School of Medicine, China.
authors.forename: Chuan-Dong
authors.initials: CD
authors.lastname: Wang
authors.affiliation: The Key Laboratory of Stem Cell Biology, Institute of Health Sciences, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences & Shanghai Jiao Tong University School of Medicine, China.
authors.forename: Xiao-Ling
authors.initials: XL
authors.lastname: Zhang
mesh_terms: D000818:Animals; D015820:Cadherins / Q000494:pharmacology*; D002470:Cell Survival / Q000187:drug effects*; D002478:Cells, Cultured; D019902:Chondrocytes / Q000187:drug effects* / Q000378:metabolism; D005109:Extracellular Matrix / Q000187:drug effects / Q000378:metabolism; D007403:Intervertebral Disc / Q000601:surgery*; D020011:Protective Agents / Q000494:pharmacology; D017207:Rats, Sprague-Dawley; D015398:Signal Transduction / Q000187:drug effects*; D054460:rho-Associated Kinases / Q000378:metabolism; D020742:rhoA GTP-Binding Protein / Q000378:metabolism
chemical_list: D015820:Cadherins; D020011:Protective Agents; D054460:rho-Associated Kinases; D020742:rhoA GTP-Binding Protein