title: A critical role for adrenomedullin-calcitonin receptor-like receptor in regulating rheumatoid fibroblast-like synoviocyte apoptosis.
abstract: Rheumatoid arthritis (RA) is characterized by fibroblast-like synoviocyte (FLS) hyperplasia, which is partly ascribable to decreased apoptosis. In this study, we show that adrenomedullin (ADM), an antiapoptotic peptide, is constitutively secreted in larger amounts by FLS from joints with RA (RA-FLS) than with osteoarthritis (OA-FLS). ADM secretion was regulated by TNF-alpha. Peptidylglycine alpha-amidating monooxygenase, the ADM-processing enzyme, was expressed at the mRNA level by both RA-FLS and OA-FLS. Constituents of the ADM heterodimeric receptor calcitonin receptor-like receptor (CRLR)/receptor activity-modifying protein (RAMP)-2 were up-regulated at the mRNA and protein levels in cultured RA-FLS compared with OA-FLS. ADM induced rapid intracellular cAMP production in FLS and reduced caspase-3 activity, DNA fragmentation, and chromatin condensation in RA-FLS exposed to apoptotic conditions, indicating that CRLR/RAMP-2 was fully functional. ADM-induced cAMP production was less marked in OA-FLS than in RA-FLS, suggesting differences in receptor regulation and expression. ADM dose-dependently inhibited RA-FLS apoptosis, and this effect was reversed by the 22-52 ADM antagonist peptide. ADM inhibited RA-FLS apoptosis triggered by extrinsic and intrinsic pathways. Our data suggest that ADM may prevent or reduce RA-FLS apoptosis, via up-regulation of its functional receptor CRLR/RAMP-2. Regulation of ADM secretion and/or CRLR/RAMP-2 activation may constitute new treatment strategies for RA.
authors.affiliation: Institut National de la Santé et de la Recherche Médicale, Unité 606, IFR 139, Centre Viggo Petersen, Hôpital Lariboisière, 2 rue Ambroise Paré, F-75010 Paris, France.
authors.forename: Benjamin
authors.initials: B
authors.lastname: Uzan
authors.forename: Hang-Korng
authors.initials: HK
authors.lastname: Ea
authors.forename: Jean-Marie
authors.initials: JM
authors.lastname: Launay
authors.forename: Jean-Michel
authors.initials: JM
authors.lastname: Garel
authors.forename: Romuald
authors.initials: R
authors.lastname: Champy
authors.forename: Michèle
authors.initials: M
authors.lastname: Cressent
authors.forename: Frédéric
authors.initials: F
authors.lastname: Lioté
mesh_terms: D000262:Adenylyl Cyclases / Q000378:metabolism; D053607:Adrenomedullin; D017209:Apoptosis / Q000187:drug effects; D001172:Arthritis, Rheumatoid / Q000235:genetics / Q000378:metabolism* / Q000473:pathology*; D058286:Calcitonin Receptor-Like Protein; D002469:Cell Separation; D002478:Cells, Cultured; D000242:Cyclic AMP / Q000378:metabolism; D017868:Cyclic AMP-Dependent Protein Kinases / Q000378:metabolism; D005347:Fibroblasts; D005786:Gene Expression Regulation; D006801:Humans; D047908:Intracellular Signaling Peptides and Proteins / Q000235:genetics / Q000378:metabolism; D008565:Membrane Proteins / Q000235:genetics / Q000378:metabolism; D010446:Peptide Fragments / Q000494:pharmacology; D010455:Peptides / Q000235:genetics / Q000378:metabolism*; D058261:Receptor Activity-Modifying Proteins; D058265:Receptors, Adrenomedullin; D018003:Receptors, Calcitonin / Q000235:genetics / Q000378:metabolism*; D018000:Receptors, Peptide / Q000037:antagonists & inhibitors / Q000378:metabolism; D015398:Signal Transduction; D013583:Synovial Membrane / Q000187:drug effects / Q000378:metabolism* / Q000473:pathology*; D014409:Tumor Necrosis Factor-alpha / Q000494:pharmacology
chemical_list: C545578:CALCRL protein, human; D058286:Calcitonin Receptor-Like Protein; D047908:Intracellular Signaling Peptides and Proteins; D008565:Membrane Proteins; D010446:Peptide Fragments; D010455:Peptides; D058261:Receptor Activity-Modifying Proteins; D058265:Receptors, Adrenomedullin; D018003:Receptors, Calcitonin; D018000:Receptors, Peptide; D014409:Tumor Necrosis Factor-alpha; D053607:Adrenomedullin; D000242:Cyclic AMP; D017868:Cyclic AMP-Dependent Protein Kinases; D000262:Adenylyl Cyclases