title: JNK phosphorylation promotes degeneration of cervical endplate chondrocytes through down-regulation of the expression of ANK in humans.
abstract: BACKGROUND
  C-Jun N-terminal kinase (JNK) signaling pathway and ankylosis gene (ANK) play a critical role in endplate chondrocytes degeneration. The purpose of this study was to investigate whether the expression levels of ANK was associated with the activation of JNK.
  
  
  METHODS
  Cartilage endplates of 49 patients were divided into the control group (n = 19) and the experimental group (n = 30). The patients in the control group were graded 0 and those in the experimental group were graded I-III according to Miller's classification. Endplate chondrocytes were isolated by enzyme digestion and cultured in vitro. The inverted phase contrast microscope, teluidine blue staining, HE staining, real time RT-PCR, and MTT were used to observe morphological appearances, biological characteristics, and growth curve of endplate chondrocytes from the cartilage endplate of the two groups. Real time RT-PCR and Western blotting were used to analyze the mRNA and protein expression levels of associated factors in the degeneration process in the cultured endplate chondrocytes with or without subjected SP600125.
  
  
  RESULTS
  The expression levels of type II collagen, aggrecan, and ANK in endplate chondrocytes of experimental group were lower than that of control group and phosphorylation level of JNK in the experimental group which was higher than that in the control group. Application of JNK phosphorylation inhibitor to degeneration chondrocytes resulted in a marked decrease in the phosphorylation level of JNK and a significant increase in the expression levels of type II collagen, aggrecan, and ANK.
  
  
  CONCLUSIONS
  The degeneration of the human cervical endplate chondrocytes might be promoted by JNK phosphorylation by down-regulating the expression of ANK.
authors.affiliation: Department of Orthopedic Surgery, Yijishan Hospital, Wannan Medical College, Wuhu, Anhui, China. xuhg@medmail.com.cn
authors.forename: Hong-guang
authors.initials: HG
authors.lastname: Xu
authors.forename: Jun-xing
authors.initials: JX
authors.lastname: Song
authors.forename: Jia-feng
authors.initials: JF
authors.lastname: Cheng
authors.forename: Ping-zhi
authors.initials: PZ
authors.lastname: Zhang
authors.forename: Hong
authors.initials: H
authors.lastname: Wang
authors.forename: Ping
authors.initials: P
authors.lastname: Liu
authors.forename: Kun
authors.initials: K
authors.lastname: Lü
authors.forename: Min
authors.initials: M
authors.lastname: Zhong
mesh_terms: D000328:Adult; D000368:Aged; D000873:Anthracenes / Q000494:pharmacology; D002478:Cells, Cultured; D002574:Cervical Vertebrae / Q000378:metabolism* / Q000473:pathology; D019902:Chondrocytes / Q000378:metabolism* / Q000473:pathology; D015536:Down-Regulation; D005260:Female; D006801:Humans; D048031:JNK Mitogen-Activated Protein Kinases / Q000378:metabolism*; D008297:Male; D008875:Middle Aged; D028061:Phosphate Transport Proteins / Q000235:genetics / Q000502:physiology*; D010766:Phosphorylation
chemical_list: C498770:ANKH protein, human; D000873:Anthracenes; D028061:Phosphate Transport Proteins; C432165:pyrazolanthrone; D048031:JNK Mitogen-Activated Protein Kinases