title: CD200Fc reduces TLR4-mediated inflammatory responses in LPS-induced rat primary microglial cells via inhibition of the NF-κB pathway.
abstract: OBJECTIVE
  Based on recent information, CD200Fc, a CD200R1 agonist, could attenuate the inflammatory response of microglial cells in autoimmune diseases and neuro-degeneration. However, the exact molecular mechanisms responsible for the anti-inflammatory activity of CD200Fc in microglial cells have not been elucidated. In the present study, we investigated the anti-inflammatory effects and the molecular mechanisms of CD200Fc in lipopolysaccharide (LPS)-stimulated rat primary microglial cells.
  
  
  METHODS
  The cell viability was measured by MTT assay. The LPS-induced cytokines release (IL-1β, IL-6, TNF-α, iNOS, MCP-1, and COX-2) was monitored by ELISA or real-time PCR, while NF-κB-related signals (MyD88, p-TAK1, TRIF, p-TBK1, p-IRF3, p-IκB, and NF-κB-P65) were assessed by real-time PCR, western blot and/or Immunofluorescent staining.
  
  
  RESULTS
  CD200Fc and/or LPS exerted no significant cytotoxicity on microglial cells. LPS reduced the CD200R1 expression in microglial cells, and this effect was attenuated by CD200Fc. In addition, CD200Fc inhibited LPS-induced expression of TLR4 and its adapter molecules (MyD88 and p-TAK1, TRIF, p-TBK1, and p-IRF3), and abolished its interactions with MyD88, TAK1, and TRIF in microglial cells. CD200Fc also attenuated LPS-induced protein expression of p-IκB and NF-κB-P65 translocation to nucleus in microglial cells. Moreover, CD200Fc suppressed the LPS-induced release of inflammatory mediators in microglial cells, including IL-1β, IL-6, TNF-α, iNOS, MCP-1, and COX-2.
  
  
  CONCLUSIONS
  These results indicated that CD200Fc displayed an anti-inflammatory effect in LPS-induced microglial cells by blocking TLR4-mediated NF-κB activation.
authors.affiliation: Department of Ophthalmology, People's Hospital of Guangxi Zhuang Autonomous Region, No. 6, Taoyuan Road, Nanning, 530021, Guangxi, People's Republic of China.
authors.forename: Li
authors.initials: L
authors.lastname: Jiang
authors.affiliation: Department of Ophthalmology, People's Hospital of Guangxi Zhuang Autonomous Region, No. 6, Taoyuan Road, Nanning, 530021, Guangxi, People's Republic of China.
authors.forename: Fan
authors.initials: F
authors.lastname: Xu
authors.affiliation: Department of Ophthalmology, People's Hospital of Guangxi Zhuang Autonomous Region, No. 6, Taoyuan Road, Nanning, 530021, Guangxi, People's Republic of China.
authors.forename: Wenjing
authors.initials: W
authors.lastname: He
authors.affiliation: Department of Ophthalmology, People's Hospital of Guangxi Zhuang Autonomous Region, No. 6, Taoyuan Road, Nanning, 530021, Guangxi, People's Republic of China.
authors.forename: Lifei
authors.initials: L
authors.lastname: Chen
authors.affiliation: Department of Ophthalmology, People's Hospital of Guangxi Zhuang Autonomous Region, No. 6, Taoyuan Road, Nanning, 530021, Guangxi, People's Republic of China.
authors.forename: Haibin
authors.initials: H
authors.lastname: Zhong
authors.affiliation: Department of Ophthalmology, People's Hospital of Guangxi Zhuang Autonomous Region, No. 6, Taoyuan Road, Nanning, 530021, Guangxi, People's Republic of China.
authors.forename: Yu
authors.initials: Y
authors.lastname: Wu
authors.affiliation: Department of Ophthalmology, People's Hospital of Guangxi Zhuang Autonomous Region, No. 6, Taoyuan Road, Nanning, 530021, Guangxi, People's Republic of China. eyezsm@163.com.
authors.forename: Siming
authors.initials: S
authors.lastname: Zeng
authors.affiliation: Department of Ophthalmology, People's Hospital of Guangxi Zhuang Autonomous Region, No. 6, Taoyuan Road, Nanning, 530021, Guangxi, People's Republic of China.
authors.forename: Li
authors.initials: L
authors.lastname: Li
authors.affiliation: Department of Ophthalmology, People's Hospital of Guangxi Zhuang Autonomous Region, No. 6, Taoyuan Road, Nanning, 530021, Guangxi, People's Republic of China. eyeminli@163.com.
authors.forename: Min
authors.initials: M
authors.lastname: Li
mesh_terms: D033942:Adaptor Proteins, Vesicular Transport / Q000378:metabolism; D000818:Animals; D000893:Anti-Inflammatory Agents / Q000494:pharmacology*; D002470:Cell Survival / Q000187:drug effects; D002478:Cells, Cultured; D016207:Cytokines / Q000378:metabolism; D007074:Immunoglobulin G / Q000494:pharmacology*; D008070:Lipopolysaccharides; D017628:Microglia / Q000187:drug effects* / Q000378:metabolism; D053594:Myeloid Differentiation Factor 88 / Q000378:metabolism; D016328:NF-kappa B / Q000037:antagonists & inhibitors*; D017207:Rats, Sprague-Dawley; D011971:Receptors, Immunologic / Q000378:metabolism; D015398:Signal Transduction; D051197:Toll-Like Receptor 4 / Q000037:antagonists & inhibitors*
chemical_list: D033942:Adaptor Proteins, Vesicular Transport; D000893:Anti-Inflammatory Agents; C529001:CD200-FC, mouse; C495490:Cd200 protein, rat; D016207:Cytokines; D007074:Immunoglobulin G; D008070:Lipopolysaccharides; D053594:Myeloid Differentiation Factor 88; D016328:NF-kappa B; D011971:Receptors, Immunologic; C523075:Ticam1 protein, rat; C495347:Tlr4 protein, rat; D051197:Toll-Like Receptor 4
keywords: CD200Fc; Inflammatory responses; Microglial cells; NF-κB; TLR4