title: Role of the NLRP3 inflammasome in the transient release of IL-1β induced by monosodium urate crystals in human fibroblast-like synoviocytes.
abstract: BACKGROUND
  To investigate whether monosodium urate (MSU) crystals induce interleukin (IL)-1β in human fibroblast-like synoviocytes (FLS), and whether the NLRP3 inflammasome is involved in the inflammatory mechanism.
  
  
  METHODS
  Human FLS isolated from explants of synovial tissue were stimulated with MSU crystals (0.001 to 0.5 mg/ml) for different time course (6 hours to 48 hours). The expressions of IL-1β, IL-6, TNF-α and NLRP3 were evaluated with ELISA, Western blot and quantitative real-time PCR.
  
  
  RESULTS
  Exposure of FLS to MSU crystals transiently induced a significant increase in IL-1β expression in culture medium with a peak at 6 h. The mRNA level of IL-1β in the FLS cells had a similar pattern at this time point. Changes in IL-6 and TNF-α expression were not observed. Simultaneously, intercellular pro-IL-1β was detected at 6 h. Furthermore, MSU crystals also induced NLRP3 mRNA and protein expression at 6 h to 48 h after MSU treatment.
  
  
  CONCLUSIONS
  MSU crystals directly increased IL-1β and intercellular NLRP3 expression in FLS cells. It is suggested that the NLRP3 inflammasome may be associated with IL-1β in FLS treated with MSU. Altogether, MSU could induce production and release of IL-1β through the NLRP3 inflammasome in human synoviocytes.
authors.affiliation: Division of Rheumatology, Huashan Hospital, Fudan University, Shanghai, China.|Institute of Rheumatology, Immunology and Allergy, Fudan University, Shanghai, China.
authors.forename: Shu-Cong
authors.initials: SC
authors.lastname: Zheng
authors.affiliation: Division of Rheumatology, Huashan Hospital, Fudan University, Shanghai, China.|Institute of Rheumatology, Immunology and Allergy, Fudan University, Shanghai, China.
authors.forename: Xiao-Xia
authors.initials: XX
authors.lastname: Zhu
authors.affiliation: Division of Rheumatology, Huashan Hospital, Fudan University, Shanghai, China.|Institute of Rheumatology, Immunology and Allergy, Fudan University, Shanghai, China.
authors.forename: Yu
authors.initials: Y
authors.lastname: Xue
authors.affiliation: Department of Anatomy, Histology and Embryology, Shanghai Medical College of Fudan University, 138 Yixueyuan Road, Shanghai, 200032 PR China.
authors.forename: Li-Hong
authors.initials: LH
authors.lastname: Zhang
authors.affiliation: Division of Rheumatology, Huashan Hospital, Fudan University, Shanghai, China.|Institute of Rheumatology, Immunology and Allergy, Fudan University, Shanghai, China.
authors.forename: He-Jian
authors.initials: HJ
authors.lastname: Zou
authors.affiliation: Institute of Rheumatology, Immunology and Allergy, Fudan University, Shanghai, China.|Division of Emergency Medicine, Boston Children's Hospital, Harvard Medical School, Boston, MA USA.
authors.forename: Jian-Hua
authors.initials: JH
authors.lastname: Qiu
authors.affiliation: Institute of Rheumatology, Immunology and Allergy, Fudan University, Shanghai, China.|Department of Anatomy, Histology and Embryology, Shanghai Medical College of Fudan University, 138 Yixueyuan Road, Shanghai, 200032 PR China.|Key Laboratory of Medical Imaging Computing and Computer Assisted Intervention of Shanghai, 138 Yixueyuan Road, Shanghai, 200032 PR China.
authors.forename: Qiong
authors.initials: Q
authors.lastname: Liu
keywords: IL-1β; Inflammasome; MSU; NLRP3; Synoviocytes