title: The receptor S1P1 overrides regulatory T cell-mediated immune suppression through Akt-mTOR.
abstract: Regulatory T cells (T(reg) cells) are critically involved in maintaining immunological tolerance, but this potent suppression must be 'quenched' to allow the generation of adaptive immune responses. Here we report that sphingosine 1-phosphate (S1P) receptor type 1 (S1P1) delivers an intrinsic negative signal to restrain the thymic generation, peripheral maintenance and suppressive activity of T(reg) cells. Combining loss- and gain-of-function genetic approaches, we found that S1P1 blocked the differentiation of thymic T(reg) precursors and function of mature T(reg) cells and affected T(reg) cell-mediated immune tolerance. S1P1 induced selective activation of the Akt-mTOR kinase pathway to impede the development and function of T(reg) cells. Dynamic regulation of S1P1 contributed to lymphocyte priming and immune homeostasis. Thus, by antagonizing T(reg) cell-mediated immune suppression, the lipid-activated S1P1-Akt-mTOR pathway orchestrates adaptive immune responses.
authors.affiliation: Department of Immunology, St. Jude Children's Research Hospital, Memphis, Tennessee, USA.
authors.forename: Guangwei
authors.initials: G
authors.lastname: Liu
authors.forename: Samir
authors.initials: S
authors.lastname: Burns
authors.forename: Gonghua
authors.initials: G
authors.lastname: Huang
authors.forename: Kelli
authors.initials: K
authors.lastname: Boyd
authors.forename: Richard L
authors.initials: RL
authors.lastname: Proia
authors.forename: Richard A
authors.initials: RA
authors.lastname: Flavell
authors.forename: Hongbo
authors.initials: H
authors.lastname: Chi
mesh_terms: D019264:Adoptive Transfer; D000818:Animals; D000831:Animals, Newborn; D015496:CD4-Positive T-Lymphocytes / Q000166:cytology / Q000276:immunology / Q000378:metabolism; D002352:Carrier Proteins / Q000378:metabolism*; D002454:Cell Differentiation / Q000276:immunology; D003106:Colon / Q000276:immunology / Q000378:metabolism / Q000473:pathology; D005260:Female; D005434:Flow Cytometry; D051858:Forkhead Transcription Factors / Q000235:genetics / Q000378:metabolism; D006706:Homeostasis / Q000276:immunology; D007108:Immune Tolerance / Q000276:immunology; D053645:Interleukin-2 Receptor alpha Subunit / Q000276:immunology; D017493:Leukocyte Common Antigens / Q000276:immunology; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL; D018345:Mice, Knockout; D008822:Mice, Transgenic; D017853:Phosphotransferases (Alcohol Group Acceptor) / Q000378:metabolism*; D051057:Proto-Oncogene Proteins c-akt / Q000378:metabolism*; D049349:Receptors, Lysosphingolipid / Q000235:genetics / Q000378:metabolism*; D015398:Signal Transduction / Q000276:immunology; D050378:T-Lymphocytes, Regulatory / Q000276:immunology* / Q000378:metabolism / Q000637:transplantation; D058570:TOR Serine-Threonine Kinases; D013950:Thymus Gland / Q000166:cytology / Q000276:immunology
chemical_list: D002352:Carrier Proteins; D051858:Forkhead Transcription Factors; C498833:Foxp3 protein, mouse; D053645:Interleukin-2 Receptor alpha Subunit; D049349:Receptors, Lysosphingolipid; D017853:Phosphotransferases (Alcohol Group Acceptor); C546843:mTOR protein, mouse; D051057:Proto-Oncogene Proteins c-akt; D058570:TOR Serine-Threonine Kinases; D017493:Leukocyte Common Antigens