Abstract
Fibroblast-like synoviocytes are important mediators of inflammatory joint damage in arthritis through the release of cytokines, but it is unknown whether their exocytosis from these particular cells is SNARE-dependent. Here, the complement of soluble N-ethylmaleimide-sensitive factor attachment protein receptors (SNAREs) in human synovial sarcoma cells (SW982) was examined with respect to the secretion of interleukin-6 (IL-6) and tumour necrosis factor α (TNFα), before and after knockdown of a synaptosome-associated protein of molecular mass 23 kDa (SNAP-23) or the vesicle-associated membrane protein 3 (VAMP-3). Wild-type SW982 cells expressed SNAP-23, VAMP-3, syntaxin isoforms 2-4 and synaptic vesicle protein 2C (SV2C). These cells showed Ca²⁺-dependent secretion of IL-6 and TNFα when stimulated by interleukin-1β (IL-1β) or in combination with K⁺ depolarization. Specific knockdown of SNAP-23 or VAMP-3 decreased the exocytosis of IL-6 and TNFα; the reduced expression of SNAP-23 caused accumulation of SV2 in the peri-nuclear area. A monoclonal antibody specific for VAMP-3 precipitated SNAP-23 and syntaxin-2 (and syntaxin-3 to a lesser extent). The formation of SDS-resistant complexes by SNAP-23 and VAMP-3 was reduced upon knockdown of SNAP-23. Although the syntaxin isoforms 2, 3 and 4 are expressed in SW982 cells, knockdown of each did not affect the release of cytokines. Collectively, these results show that SNAP-23 and VAMP-3 participate in IL-1β-induced Ca²⁺-dependent release of IL-6 and TNFα from SW982 cells.
Keywords:
IL-6; SNAREs; SW982; TNFα; arthritis.
© 2013 FEBS.
Publication types
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Research Support, Non-U.S. Gov't
MeSH terms
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Anti-Inflammatory Agents / pharmacology
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Anti-Inflammatory Agents / therapeutic use
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Arthritis / drug therapy
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Arthritis / immunology
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Arthritis / metabolism
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Calcium Signaling / drug effects
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Cell Line, Tumor
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Exocytosis* / drug effects
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Humans
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Interleukin-1beta / metabolism
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Interleukin-6 / metabolism*
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Membrane Glycoproteins / antagonists & inhibitors
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Membrane Glycoproteins / genetics
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Membrane Glycoproteins / metabolism
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Molecular Targeted Therapy
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Nerve Tissue Proteins / antagonists & inhibitors
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Nerve Tissue Proteins / genetics
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Nerve Tissue Proteins / metabolism
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Protein Isoforms / antagonists & inhibitors
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Protein Isoforms / genetics
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Protein Isoforms / metabolism
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Protein Transport / drug effects
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Qa-SNARE Proteins / antagonists & inhibitors
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Qa-SNARE Proteins / genetics
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Qa-SNARE Proteins / metabolism
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Qb-SNARE Proteins / antagonists & inhibitors
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Qb-SNARE Proteins / genetics
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Qb-SNARE Proteins / metabolism*
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Qc-SNARE Proteins / antagonists & inhibitors
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Qc-SNARE Proteins / genetics
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Qc-SNARE Proteins / metabolism*
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RNA Interference
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RNA, Small Interfering
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Receptors, Interleukin-1 / metabolism
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Synovial Membrane / drug effects
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Synovial Membrane / immunology
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Synovial Membrane / metabolism*
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Tumor Necrosis Factor-alpha / metabolism*
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Vesicle-Associated Membrane Protein 3 / antagonists & inhibitors
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Vesicle-Associated Membrane Protein 3 / genetics
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Vesicle-Associated Membrane Protein 3 / metabolism*
Substances
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Anti-Inflammatory Agents
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IL6 protein, human
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Interleukin-1beta
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Interleukin-6
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Membrane Glycoproteins
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Nerve Tissue Proteins
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Protein Isoforms
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Qa-SNARE Proteins
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Qb-SNARE Proteins
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Qc-SNARE Proteins
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RNA, Small Interfering
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Receptors, Interleukin-1
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SNAP23 protein, human
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SV2C protein, human
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TNF protein, human
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Tumor Necrosis Factor-alpha
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VAMP3 protein, human
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Vesicle-Associated Membrane Protein 3