title: Adenosine promotes Foxp3 expression in Treg cells in sepsis model by activating JNK/AP-1 pathway.
abstract: OBJECTIVE
  Forkhead/winged helix transcription factor p3 (Foxp3) increases in CD4(+)CD25(+)Treg cells during sepsis; however, related mechanisms are unclear. Our study aimed to explore the possible molecular mechanisms of high expression of Foxp3 in Treg cells during sepsis.
  
  
  METHODS
  Sepsis was induced by cecal ligation and puncture (CLP) method. CD4(+)CD25(+)Treg cells were isolated from peripheral blood and identified by flow cytometry (FCM). Treg cells were cultured with or without adenosine, adenosine agonist, adenosine antagonist, SMAD family member 3 (Smad3) agonist (transforming growth factor (TGF)-β1), or C-Jun N-Terminal Kinase (JNK) inhibitor. Expression levels of Foxp3 and activator protein 1 (AP-1) were determined. The binding of c-Fos or c-Jun to the Foxp3 promoter was then evaluated by the chromatin immunoprecipitation (ChIP) assay and quantified by quantitative real-time PCR (qRT-PCR). The mRNA and protein levels of Foxp3 were determined after transfection with siRNA against c-Fos, Fra-2, c-Jun or JunD.
  
  
  RESULTS
  Pharmacological inhibition of both adenosine and JNK reduced Foxp3 protein levels. JNK/AP-1 activation was involved in increased levels of Foxp3 protein in CD4(+)CD25(+)Treg cells. AP-1 regulated activity of Foxp3 promoter in Treg cells, and the induction of c-Fos or c-Jun activity leads to elevated transcription of Foxp3 gene. Knockdown of c-Fos, Fra-2, c-Jun, or JunD levels also reduced Foxp3 expression.
  
  
  CONCLUSIONS
  We confirm that adenosine plays significant roles in the high expression of Foxp3. Adenosine promotes Foxp3 expression in Treg cells during sepsis via JNK/AP-1 pathway.
authors.affiliation: Department of Anesthesiology and Intensive Care Medicine, Changhai Hospital, Second Military Medical University Shanghai 200433, PR China.
authors.forename: Rui
authors.initials: R
authors.lastname: Bao
authors.affiliation: Department of Anesthesiology and Intensive Care Medicine, Changhai Hospital, Second Military Medical University Shanghai 200433, PR China.
authors.forename: Jiong
authors.initials: J
authors.lastname: Hou
authors.affiliation: Department of Anesthesiology and Intensive Care Medicine, Changhai Hospital, Second Military Medical University Shanghai 200433, PR China.
authors.forename: Yan
authors.initials: Y
authors.lastname: Li
authors.affiliation: Department of Anesthesiology and Intensive Care Medicine, Changhai Hospital, Second Military Medical University Shanghai 200433, PR China.
authors.forename: Jinjun
authors.initials: J
authors.lastname: Bian
authors.affiliation: Department of Anesthesiology and Intensive Care Medicine, Changhai Hospital, Second Military Medical University Shanghai 200433, PR China.
authors.forename: Xiaoming
authors.initials: X
authors.lastname: Deng
authors.affiliation: Department of Physiology, Second Military Medical University Shanghai 200433, PR China.
authors.forename: Xiaoyan
authors.initials: X
authors.lastname: Zhu
authors.affiliation: Department of Anesthesiology and Intensive Care Medicine, Changhai Hospital, Second Military Medical University Shanghai 200433, PR China.
authors.forename: Tao
authors.initials: T
authors.lastname: Yang
keywords: Foxp3; JNK/AP-1 pathway; Sepsis; adenosine; regulatory T cells