title: Tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) induces rheumatoid arthritis synovial fibroblast proliferation through mitogen-activated protein kinases and phosphatidylinositol 3-kinase/Akt.
abstract: A hallmark of rheumatoid arthritis (RA) is the pseudo-tumoral expansion of fibroblast-like synoviocytes (FLSs), and the RA FLS has therefore been proposed as a therapeutic target. Tumor necrosis factor (TNF)-related apoptosis-inducing ligand (TRAIL) has been described as a pro-apoptotic factor on RA FLSs and, therefore, suggested as a potential drug. Here we report that exposure to TRAIL-induced apoptosis in a portion (up to 30%) of RA FLSs within the first 24 h. In the cells that survived, TRAIL induced RA FLS proliferation in a dose-dependent manner, with maximal proliferation observed at 0.25 nm. This was blocked by a neutralizing anti-TRAIL antibody. RA FLSs were found to express constitutively TRAIL receptors 1 and 2 (TRAIL-R1 and TRAIL-R2) on the cell surface. TRAIL-R2 appears to be the main mediator of TRAIL-induced stimulation, as RA FLS proliferation induced by an agonistic anti-TRAIL-R2 antibody was comparable with that induced by TRAIL. TRAIL activated the mitogen-activated protein kinases ERK and p38, as well as the phosphatidylinositol 3-kinase (PI3K)/Akt signaling pathway with kinetics similar to those of TNF-alpha. Moreover, TRAIL-induced RA FLS proliferation was inhibited by the protein kinase inhibitors PD98059, SB203580, and LY294002, confirming the involvement of the ERK, p38, and PI3 kinase/Akt signaling pathways. This dual functionality of TRAIL in stimulating apoptosis and proliferation has important implications for its use in the treatment of RA.
authors.affiliation: INSERM Unit 454, Centre Hospitalier Universitaire Arnaud de Villeneuve, Centre Hospitalier Universitaire Lapeyronie, 34295 Montpellier, France. j-morel@chu-montpellier.fr
authors.forename: Jacques
authors.initials: J
authors.lastname: Morel
authors.forename: Rachel
authors.initials: R
authors.lastname: Audo
authors.forename: Michael
authors.initials: M
authors.lastname: Hahne
authors.forename: Bernard
authors.initials: B
authors.lastname: Combe
mesh_terms: D051017:Apoptosis Regulatory Proteins; D001172:Arthritis, Rheumatoid / Q000378:metabolism*; D049109:Cell Proliferation; D048049:Extracellular Signal-Regulated MAP Kinases / Q000378:metabolism; D005347:Fibroblasts / Q000378:metabolism; D006801:Humans; D008562:Membrane Glycoproteins / Q000235:genetics / Q000378:metabolism*; D020928:Mitogen-Activated Protein Kinases / Q000378:metabolism*; D016328:NF-kappa B / Q000378:metabolism; D019869:Phosphatidylinositol 3-Kinases / Q000378:metabolism*; D010766:Phosphorylation; D017346:Protein Serine-Threonine Kinases / Q000378:metabolism*; D021381:Protein Transport / Q000502:physiology; D011518:Proto-Oncogene Proteins / Q000378:metabolism*; D051057:Proto-Oncogene Proteins c-akt; D018124:Receptors, Tumor Necrosis Factor / Q000235:genetics / Q000378:metabolism; D013583:Synovial Membrane / Q000378:metabolism*; D053221:TNF-Related Apoptosis-Inducing Ligand; D014409:Tumor Necrosis Factor-alpha / Q000235:genetics / Q000378:metabolism*; D048051:p38 Mitogen-Activated Protein Kinases / Q000378:metabolism
chemical_list: D051017:Apoptosis Regulatory Proteins; D048049:Extracellular Signal-Regulated MAP Kinases; D008562:Membrane Glycoproteins; D020928:Mitogen-Activated Protein Kinases; D016328:NF-kappa B; D019869:Phosphatidylinositol 3-Kinases; D017346:Protein Serine-Threonine Kinases; D011518:Proto-Oncogene Proteins; D051057:Proto-Oncogene Proteins c-akt; D018124:Receptors, Tumor Necrosis Factor; D053221:TNF-Related Apoptosis-Inducing Ligand; D014409:Tumor Necrosis Factor-alpha; D048051:p38 Mitogen-Activated Protein Kinases; C505653:TNFSF10 protein, human; C494918:AKT1 protein, human