title: Cortisol-mediated adhesion of synovial fibroblasts is dependent on the degradation of anandamide and activation of the endocannabinoid system.
abstract: OBJECTIVE
  In rheumatoid arthritis (RA) synovial fluid, levels of the endocannabinoids anandamide (AEA) and 2-arachidonylglycerol are elevated. Since synovial fibroblasts (SFs) possess all of the enzymes necessary for endocannabinoid synthesis, it is likely that these cells contribute significantly to elevated endocannabinoid levels. While glucocorticoids initiate endocannabinoid synthesis in neurons, this study was undertaken to test whether cortisol also regulates endocannabinoid levels in mesenchymal cells such as SFs, and whether this interferes with integrin-mediated adhesion.
  
  
  METHODS
  Adhesion was determined in 1-minute intervals over 60 minutes using an xCELLigence system. Slopes from individual treatment groups were averaged and compared to the control. Fatty acid amide hydrolase (FAAH) and cyclooxygenase 2 (COX-2) were detected by immunocytochemistry, and AEA was detected by mass spectrometry.
  
  
  RESULTS
  Cortisol increased the adhesion of RASFs and osteoarthritis SFs with a maximum of 200% at both 10(-7) M and 10(-8) M. When cortisol was administered together with either cannabinoid receptor 1 (CB(1) ) antagonist (rimonabant; 100 nM), CB(2)  antagonist (JTE907; 100 nM), transient receptor potential vanilloid channel 1 (TRPV-1) antagonist (capsazepine; 1 μM), FAAH inhibitor, or COX-2 inhibitor, adhesion was reduced below the level in controls. Concomitant inhibition of FAAH and COX-2 reversed these effects. Mass spectrometry revealed the presence of AEA in SFs.
  
  
  CONCLUSIONS
  Our findings indicate that glucocorticoid-induced adhesion is dependent on CB(1) /CB(2) /TRPV-1 activation. Since AEA is produced in SFs, this endocannabinoid is the most likely candidate to mediate these effects. Since AEA levels are regulated by COX-2 and FAAH, inhibition of both enzymes along with low-dose glucocorticoids may provide a therapeutic option to maximally boost the endocannabinoid system in RA, with possible beneficial effects.
authors.affiliation: University Hospital Regensburg, Regensburg, Germany. torsten.lowin@ukr.de
authors.forename: Torsten
authors.initials: T
authors.lastname: Lowin
authors.forename: Wentao
authors.initials: W
authors.lastname: Zhu
authors.forename: Katja
authors.initials: K
authors.lastname: Dettmer-Wilde
authors.forename: Rainer H
authors.initials: RH
authors.lastname: Straub
mesh_terms: D000368:Aged; D000581:Amidohydrolases / Q000378:metabolism; D001095:Arachidonic Acids / Q000378:metabolism*; D001172:Arthritis, Rheumatoid / Q000378:metabolism / Q000473:pathology; D002448:Cell Adhesion / Q000187:drug effects*; D002478:Cells, Cultured; D051546:Cyclooxygenase 2 / Q000378:metabolism; D004305:Dose-Response Relationship, Drug; D063388:Endocannabinoids / Q000378:metabolism*; D005260:Female; D005347:Fibroblasts / Q000187:drug effects / Q000378:metabolism / Q000473:pathology*; D005353:Fibronectins / Q000378:metabolism; D006801:Humans; D006854:Hydrocortisone / Q000494:pharmacology*; D008297:Male; D008875:Middle Aged; D020370:Osteoarthritis, Knee / Q000378:metabolism / Q000473:pathology; D053284:Polyunsaturated Alkamides / Q000378:metabolism*; D013583:Synovial Membrane / Q000187:drug effects / Q000378:metabolism / Q000473:pathology*; D000099252:Fatty Acid Amide Hydrolases
chemical_list: D000581:Amidohydrolases; D001095:Arachidonic Acids; D051546:Cyclooxygenase 2; D063388:Endocannabinoids; D005353:Fibronectins; D006854:Hydrocortisone; D053284:Polyunsaturated Alkamides; D000099252:Fatty Acid Amide Hydrolases; C078814:anandamide