title: CCL20 stimulates proinflammatory mediator synthesis in human fibroblast-like synoviocytes through a MAP kinase-dependent process with transcriptional and posttranscriptional control.
abstract: OBJECTIVE
  To compare levels of the chemokine CCL20 and its receptor CCR6 in donor, osteoarthritic (OA), and rheumatoid arthritis (RA) synovium; and to determine the molecular mechanism of cellular activation induced by chemokine/receptor ligation in human fibroblast-like synoviocytes (FLS).
  
  
  METHODS
  Synovia and isolated FLS from donor, OA, and RA joints were analyzed for CCL20 and CCR6 expression by RT-PCR and immunohistochemistry. The effect of CCL20 on cytokines and mediators of cartilage degradation was examined by PCR for mRNA expression levels and ELISA, and Western blotting for protein. CCL20-dependent transcriptional and posttranscriptional activation of target genes was monitored using reporter constructs and luciferase assays in transfected donor FLS.
  
  
  RESULTS
  CCL20 and CCR6 proteins were abundantly expressed in RA synovial lining cells compared to donor or OA synovia as judged by immunohistochemistry. RT-PCR of synovial extracts confirmed the predominance of CCL20/CCR6 mRNA expression in RA synovium. CCL20 mRNA expression was low in donor FLS, but increased dramatically after stimulation with recombinant human (rh) interleukin 1ß (IL-1ß). rhCCL20 increased mRNA and protein expression of COX-2, IL-1ß, tumor necrosis factor-α, IL-6, and the matrix-destructive metalloprotease MMP-3 in donor FLS cultures. High constitutive levels of IL-6 were released from RA synovia; CCL20-induced expression of IL-6 occurred through an NSAID/COXIB-sensitive process. CCL20-induced expression of COX-2 was mediated by a PLCP1/PKCα/MEK1/2/ERK1/2-dependent pathway involving both transcriptional and posttranscriptional mechanisms.
  
  
  CONCLUSIONS
  CCL20/CCR6 may play an important role in the pathogenesis of RA by assembling the molecular and cellular components orchestrating synovitis.
authors: Department of Pathology, 11-5076 Faculty of Medicine, Beirut, Lebanon. nada.aladdin@usj.edu.lb
authors: Nada
authors: N
authors: Alaaeddine
authors: George
authors: G
authors: Hilal
authors: Raffic
authors: R
authors: Baddoura
authors: John
authors: J
authors: Antoniou
authors: John A
authors: JA
authors: Di Battista
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001172:Arthritis, Rheumatoid / Q000378:metabolism* / Q000473:pathology; D002478:Cells, Cultured; D054418:Chemokine CCL20 / Q000235:genetics / Q000502:physiology*; D005347:Fibroblasts / Q000378:metabolism* / Q000473:pathology; D006801:Humans; D018836:Inflammation Mediators / Q000378:metabolism* / Q000502:physiology; D020935:MAP Kinase Signaling System / Q000235:genetics*; D008875:Middle Aged; D010003:Osteoarthritis / Q000378:metabolism* / Q000473:pathology; D014176:Protein Biosynthesis / Q000502:physiology; D054399:Receptors, CCR6 / Q000502:physiology; D013585:Synovitis / Q000378:metabolism* / Q000473:pathology; D014158:Transcription, Genetic / Q000502:physiology; D055815:Young Adult
chemical_list: C108355:CCL20 protein, human; C106311:CCR6 protein, human; D054418:Chemokine CCL20; D018836:Inflammation Mediators; D054399:Receptors, CCR6