Role of Protein Kinase A in Collagenase‐1 Gene Regulation by Prostaglandin E1: Studies in a Rabbit Synoviocyte Cell Line, HIG‐82

• Published in: Journal of bone and mineral research 1997-04, Vol.12 (4), p.561-567
• Main Authors: Suzuki, Koji, Rapuano, Bruce E., Bockman, Richard S.
• Format: Article
• Language: English
• Subjects: Alprostadil - pharmacology; Animals; Biological and medical sciences; Cell Line; Colforsin - pharmacology; Collagenases - genetics; Cyclic AMP - analogs & derivatives; Cyclic AMP - pharmacology; Cyclic AMP-Dependent Protein Kinases - antagonists & inhibitors; Cyclic AMP-Dependent Protein Kinases - metabolism; Enzyme Induction; Enzyme Inhibitors - pharmacology; Fundamental and applied biological sciences. Psychology; Gene expression; Gene Expression Regulation, Enzymologic - drug effects; Humans; Interleukin-1 - pharmacology; Isoenzymes - genetics; Isoquinolines - pharmacology; Matrix Metalloproteinase 1; Molecular and cellular biology; Molecular genetics; Protein Kinase C - genetics; Protein Kinase C-alpha; Rabbits; RNA, Messenger - metabolism; Sulfonamides; Synovial Membrane - cytology; Synovial Membrane - enzymology; Thionucleotides - pharmacology; Transfection
• ISSN: 0884-0431; 1523-4681
• DOI: 10.1359/jbmr.1997.12.4.561

Gene expression of the matrix‐degrading enzyme collagenase‐1 in rabbit synoviocytes and human fibroblasts is down‐regulated by prostaglandin E1 (PGE1) through a cyclic adenosine monophosphate (cAMP)–dependent pathway. In the current study, we examined the role of protein kinase A (PKA) in the PGE1‐mediated effect on collagenase‐1 gene expression. Collagenase‐1 gene expression was rapidly induced several‐fold above control both by a phorbol ester, 12‐o‐tetradecanoyl phorbol 13 acetate, and interleukin‐1β (IL‐1β) in HIG‐82 synoviocytes. Treatment with PGE1 and forskolin increased PKA activity in the HIG‐82 cells within 15 minutes of adding the stimulating agents. Two inhibitors of PKA, the isoquinoline‐sulfonamide derivative, H‐89 and a cAMP analog, RpcAMP, blocked the ability of PGE1 to down‐regulate collagenase‐1 gene expression. However, if PGE1 was added from 6 h to 30 minutes before the PKA inhibitor H‐89, collagenase‐1 gene expression was inhibited. Constitutive PKA activity was increased in HIG‐82 synoviocytes stably transfected with an expression vector pCMV.Cα that caused the HIG‐82 cells to overexpress an active catalytic subunit of PKA. Cells stably transfected with an inactive, mutated C‐α‐variant showed no change in PKA activity. Collagenase‐1 mRNA levels in TPA‐stimulated cells were reduced to baseline levels in the pCMV.Cα but not in the mutated C‐α–transfected cells. These data show the importance of PKA in regulating collagenase‐1 gene expression in a synoviocyte cell line.