title: miR-146a facilitates replication of dengue virus by dampening interferon induction by targeting TRAF6.
abstract: OBJECTIVE
  To investigate the role of miR-146a in dengue virus (DENV) replication.
  
  
  METHODS
  Expression levels of miR-146a were measured by real-time PCR and Northern blot. Role of miR-146a was tested by overexpression and inhibition assays. Real-time PCR and 50% tissue culture infective dose (TCID50) assays were used to detect RNA levels and extracellular yields of DENV respectively. Interferon (IFN) levels induced by DENV infection were measured by real-time PCR and ELISA respectively. IFN-β neutralization and RNAi were used to test the involvement of IFN-β in the effects of miR-146a. TNFR-associated factor 6 (TRAF6) level was measured by Western-blot.
  
  
  RESULTS
  miR-146a expression was significantly increased in primary human monocytes and THP-1 cells upon DENV infection. Overexpression of miR-146a increased DENV2 replication, while inhibition of miR-146a decreased the viral replication. miR-146a impaired the IFN production and the DENV2 replication suppressed by miR-146a inhibition was partially restored by neutralization of IFN-β or depletion of interferon receptor (IFNAR) 1 or 2. Furthermore, miR-146a targets TRAF6 and overexpression of TRAF6 reversed the effects of miR-146a on IFN-β induction and viral replication.
  
  
  CONCLUSIONS
  DENV infection significantly induced the expression of miR-146a, which facilitated viral replication by targeting TRAF6 and dampening IFN-β production.
authors.affiliation: Department of Immunology, Institute of Human Virology, Zhongshan School of Medicine, Sun Yat-sen University, Guangzhou 510080, China.
authors.forename: Siyu
authors.initials: S
authors.lastname: Wu
authors.forename: Li
authors.initials: L
authors.lastname: He
authors.forename: Yuye
authors.initials: Y
authors.lastname: Li
authors.forename: Tinglong
authors.initials: T
authors.lastname: Wang
authors.forename: Lianqiang
authors.initials: L
authors.lastname: Feng
authors.forename: Lifang
authors.initials: L
authors.lastname: Jiang
authors.forename: Ping
authors.initials: P
authors.lastname: Zhang
authors.forename: Xi
authors.initials: X
authors.lastname: Huang
mesh_terms: D015152:Blotting, Northern; D015153:Blotting, Western; D002478:Cells, Cultured; D003716:Dengue Virus / Q000276:immunology* / Q000502:physiology*; D004797:Enzyme-Linked Immunosorbent Assay; D020869:Gene Expression Profiling; D006801:Humans; D016899:Interferon-beta / Q000096:biosynthesis / Q000276:immunology*; D035683:MicroRNAs / Q000235:genetics / Q000378:metabolism*; D009000:Monocytes / Q000276:immunology / Q000821:virology; D060888:Real-Time Polymerase Chain Reaction; D048029:TNF Receptor-Associated Factor 6 / Q000037:antagonists & inhibitors* / Q000378:metabolism; D014779:Virus Replication
chemical_list: C542542:MIRN146 microRNA, human; D035683:MicroRNAs; D048029:TNF Receptor-Associated Factor 6; D016899:Interferon-beta
keywords: Dengue virus; Interferon; MicroRNA; Replication; TRAF6