title: n-3 polyunsaturated fatty acids suppress CD4(+) T cell proliferation by altering phosphatidylinositol-(4,5)-bisphosphate [PI(4,5)P2] organization.
abstract: The mechanisms by which n-3 polyunsaturated fatty acids (n-3 PUFA), abundant in fish oil, exert their anti-inflammatory effects have not been rigorously defined. We have previously demonstrated that n-3 PUFA decrease the amount of phosphatidylinositol-(4,5)-bisphosphate, [PI(4,5)P2], in CD4(+) T cells, leading to suppressed actin remodeling upon activation. Since discrete pools of PI(4,5)P2 exist in the plasma membrane, we determined whether n-3 PUFA modulate spatial organization of PI(4,5)P2 relative to raft and non-raft domains. We used Förster resonance energy transfer (FRET) to demonstrate that lipid raft mesodomains in the plasma membrane of CD4(+) T cells enriched in n-3 PUFA display increased co-clustering of Lck(N10) and LAT(ΔCP), markers of lipid rafts. CD4(+) T cells enriched in n-3 PUFA also exhibited a depleted plasma membrane non-raft PI(4,5)P2 pool as detected by decreased co-clustering of Src(N15), a non-raft marker, and PH(PLC-δ), a PI(4,5)P2 reporter. Incubation with exogenous PI(4,5)P2 rescued the effects on the non-raft PI(4,5)P2 pool, and reversed the suppression of T cell proliferation in CD4(+) T cells enriched with n-3 PUFA. Furthermore, CD4(+) T cells isolated from mice fed a 4% docosahexaenoic acid (DHA)-enriched diet exhibited a decrease in the non-raft pool of PI(4,5)P2, and exogenous PI(4,5)P2 reversed the suppression of T cell proliferation. Finally, these effects were not due to changes to post-translational lipidation, since n-3 PUFA did not alter the palmitoylation status of signaling proteins. These data demonstrate that n-3 PUFA suppress T cell proliferation by altering plasma membrane topography and the spatial organization of PI(4,5)P2.
authors.affiliation: Department of Biochemistry and Biophysics, Texas A&M University, College Station, TX, USA; Department of Nutrition and Food Science, Texas A&M University, College Station, TX, USA; Program in Integrative Nutrition and Complex Diseases, Texas A&M University, College Station, TX, USA.
authors.forename: Tim Y
authors.initials: TY
authors.lastname: Hou
authors.affiliation: Center for Translational Environmental Health Research, Texas A&M University, College Station, TX, USA; Department of Veterinary Integrative Biosciences, Texas A&M University, College Station, TX, USA.
authors.forename: Rola
authors.initials: R
authors.lastname: Barhoumi
authors.affiliation: Department of Nutrition and Food Science, Texas A&M University, College Station, TX, USA; Program in Integrative Nutrition and Complex Diseases, Texas A&M University, College Station, TX, USA.
authors.forename: Yang-Yi
authors.initials: YY
authors.lastname: Fan
authors.affiliation: Department of Veterinary Pathobiology, Texas A&M University, College Station, TX, USA.
authors.forename: Gonzalo M
authors.initials: GM
authors.lastname: Rivera
authors.affiliation: Department of Early Discovery Biochemistry, Genentech, South San Francisco, CA, USA.
authors.forename: Rami N
authors.initials: RN
authors.lastname: Hannoush
authors.affiliation: Program in Integrative Nutrition and Complex Diseases, Texas A&M University, College Station, TX, USA; Center for Translational Environmental Health Research, Texas A&M University, College Station, TX, USA; Department of Microbial Pathogenesis and Immunology, Texas A&M University Health Science Center, College Station, TX, USA.
authors.forename: David N
authors.initials: DN
authors.lastname: McMurray
authors.affiliation: Department of Biochemistry and Biophysics, Texas A&M University, College Station, TX, USA; Department of Nutrition and Food Science, Texas A&M University, College Station, TX, USA; Program in Integrative Nutrition and Complex Diseases, Texas A&M University, College Station, TX, USA; Center for Translational Environmental Health Research, Texas A&M University, College Station, TX, USA; Department of Microbial Pathogenesis and Immunology, Texas A&M University Health Science Center, College Station, TX, USA. Electronic address: r-chapkin@tamu.edu.
authors.forename: Robert S
authors.initials: RS
authors.lastname: Chapkin
mesh_terms: D048868:Adaptor Proteins, Signal Transducing / Q000235:genetics / Q000378:metabolism; D000818:Animals; D015415:Biomarkers / Q000378:metabolism; D015496:CD4-Positive T-Lymphocytes / Q000737:chemistry / Q000166:cytology / Q000187:drug effects*; D049109:Cell Proliferation / Q000187:drug effects*; D004041:Dietary Fats / Q000494:pharmacology*; D004281:Docosahexaenoic Acids / Q000494:pharmacology*; D015870:Gene Expression; D005822:Genetic Vectors; D016086:Lentivirus / Q000235:genetics; D021962:Membrane Microdomains / Q000737:chemistry / Q000187:drug effects* / Q000378:metabolism; D008565:Membrane Proteins / Q000235:genetics / Q000378:metabolism; D051379:Mice; D008810:Mice, Inbred C57BL; D019269:Phosphatidylinositol 4,5-Diphosphate / Q000737:chemistry* / Q000378:metabolism / Q000494:pharmacology; D054803:Phospholipase C delta / Q000235:genetics / Q000378:metabolism; D010750:Phosphoproteins / Q000235:genetics / Q000378:metabolism; D061251:Primary Cell Culture; D019061:src-Family Kinases / Q000235:genetics / Q000378:metabolism
chemical_list: D048868:Adaptor Proteins, Signal Transducing; D015415:Biomarkers; D004041:Dietary Fats; C491734:Lat protein, mouse; D008565:Membrane Proteins; D019269:Phosphatidylinositol 4,5-Diphosphate; D010750:Phosphoproteins; C402726:Sh2d2a protein, mouse; D004281:Docosahexaenoic Acids; D019061:src-Family Kinases; D054803:Phospholipase C delta
keywords: Fluorescence resonance energy transfer; Membrane; Phosphatidylinositol; Polyunsaturated fatty acids; T cell