title: A peripheral neuroimmune link: glutamate agonists upregulate NMDA NR1 receptor mRNA and protein, vimentin, TNF-alpha, and RANTES in cultured human synoviocytes.
abstract: Human primary and clonal synovial cells were incubated with glutamate receptor agonists to assess their modulating influence on glutamate receptors N-methyl-d-aspartate (NMDA) NR1 and NR2 and inflammatory cytokines to determine potential for paracrine or autocrine (neurocrine) upregulation of glutamate receptors, as has been shown for bone and chondrocytes. Clonal SW982 synoviocytes constitutively express vimentin, smooth muscle actin (SMA), and NMDA NR1 and NR2. Coincubation (6 h) with glutamate agonists NMDA (5 microM), and the NMDA NR1 glycine site activator (+/-)1-aminocyclopentane-cis-1,3-dicarboxylic acid (5 muM), significantly increases cellular mRNA and protein levels of glutamate receptors, as well as increasing vimentin, SMA, tumor necrosis factor-alpha, and RANTES (regulated on activation, normal T-cell expressed and secreted), assessed qualitatively and quantitatively with nucleotide amplification, image analysis of immunocytochemical staining, fluorescein-activated cell sorting, Western blotting, and immunoassays. Human primary synovial cells harvested from patients with arthritic conditions also constitutively expressed NMDA NR1 with increases after agonist treatment. Glutamate receptor agonist-induced increases were blocked by the noncompetitive glutamate antagonist MK-801 (8 microg/ml) and NR1 blocking antibody. Coincubation with glutamate agonists and phorbol 12-myristate 13-acetate, a protein kinase C activator, significantly enhanced mean levels of TNF-alpha and RANTES in SW982 cell supernatants compared with incubation with either agent alone. Increases were diminished with protein kinase inhibitor and NR1 blocking antibody. The functional activation of glutamate receptors on human synoviocytes establishes a neurogenic cell signaling link between neurotransmitter glutamate released from nerve terminals and target cells in the joint capsule. The influence of glutamate on subsequent release of cellular proinflammatory mediators in non-neural tissue for activation of downstream immune events supports a peripheral neuroimmune link in arthritis.
authors.affiliation: Department of Neuroscience and Cell Biology, University of Texas Medical Branch, Galveston, Texas, USA.
authors.forename: Terry A
authors.initials: TA
authors.lastname: McNearney
authors.forename: Yinghong
authors.initials: Y
authors.lastname: Ma
authors.forename: Yueping
authors.initials: Y
authors.lastname: Chen
authors.forename: Giulio
authors.initials: G
authors.lastname: Taglialatela
authors.forename: Huaizhi
authors.initials: H
authors.lastname: Yin
authors.forename: Wen-Ru
authors.initials: WR
authors.lastname: Zhang
authors.forename: Karin N
authors.initials: KN
authors.lastname: Westlund
mesh_terms: D000818:Animals; D001168:Arthritis / Q000378:metabolism / Q000503:physiopathology; D039481:CD11b Antigen / Q000378:metabolism; D045744:Cell Line, Tumor; D018946:Chemokine CCL5 / Q000378:metabolism*; D003515:Cycloleucine / Q000031:analogs & derivatives / Q000494:pharmacology; D016291:Dizocilpine Maleate / Q000494:pharmacology; D018690:Excitatory Amino Acid Agonists / Q000494:pharmacology; D018691:Excitatory Amino Acid Antagonists / Q000494:pharmacology; D006801:Humans; D016202:N-Methylaspartate / Q000494:pharmacology; D020078:Neurogenic Inflammation / Q000378:metabolism / Q000503:physiopathology*; D015213:Neuroimmunomodulation / Q000502:physiology; D011493:Protein Kinase C / Q000378:metabolism; D012333:RNA, Messenger / Q000378:metabolism; D051381:Rats; D017464:Receptors, Complement 3d / Q000378:metabolism; D017470:Receptors, Glutamate / Q000378:metabolism; D016194:Receptors, N-Methyl-D-Aspartate / Q000819:agonists / Q000235:genetics* / Q000378:metabolism; D013584:Sarcoma, Synovial; D013583:Synovial Membrane / Q000166:cytology / Q000502:physiology; D013585:Synovitis / Q000378:metabolism / Q000503:physiopathology*; D014409:Tumor Necrosis Factor-alpha / Q000378:metabolism*; D015854:Up-Regulation / Q000187:drug effects / Q000502:physiology; D014746:Vimentin / Q000235:genetics / Q000378:metabolism*
chemical_list: C483024:CCL5 protein, human; D039481:CD11b Antigen; D018946:Chemokine CCL5; D018690:Excitatory Amino Acid Agonists; D018691:Excitatory Amino Acid Antagonists; C509295:ITGAM protein, human; C409466:NR1 NMDA receptor; D012333:RNA, Messenger; D017464:Receptors, Complement 3d; D017470:Receptors, Glutamate; D016194:Receptors, N-Methyl-D-Aspartate; D014409:Tumor Necrosis Factor-alpha; D014746:Vimentin; D003515:Cycloleucine; C036361:1-amino-1,3-dicarboxycyclopentane; D016202:N-Methylaspartate; D016291:Dizocilpine Maleate; D011493:Protein Kinase C