n-3 polyunsaturated fatty acids suppress CD4(+) T cell proliferation by altering phosphatidylinositol-(4,5)-bisphosphate [PI(4,5)P2] organization

Biochim Biophys Acta. 2016 Jan;1858(1):85-96. doi: 10.1016/j.bbamem.2015.10.009. Epub 2015 Oct 23.

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.

Keywords: Fluorescence resonance energy transfer; Membrane; Phosphatidylinositol; Polyunsaturated fatty acids; T cell.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, Non-P.H.S.

MeSH terms

  • Adaptor Proteins, Signal Transducing / genetics
  • Adaptor Proteins, Signal Transducing / metabolism
  • Animals
  • Biomarkers / metabolism
  • CD4-Positive T-Lymphocytes / chemistry
  • CD4-Positive T-Lymphocytes / cytology
  • CD4-Positive T-Lymphocytes / drug effects*
  • Cell Proliferation / drug effects*
  • Dietary Fats / pharmacology*
  • Docosahexaenoic Acids / pharmacology*
  • Gene Expression
  • Genetic Vectors
  • Lentivirus / genetics
  • Membrane Microdomains / chemistry
  • Membrane Microdomains / drug effects*
  • Membrane Microdomains / metabolism
  • Membrane Proteins / genetics
  • Membrane Proteins / metabolism
  • Mice
  • Mice, Inbred C57BL
  • Phosphatidylinositol 4,5-Diphosphate / chemistry*
  • Phosphatidylinositol 4,5-Diphosphate / metabolism
  • Phosphatidylinositol 4,5-Diphosphate / pharmacology
  • Phospholipase C delta / genetics
  • Phospholipase C delta / metabolism
  • Phosphoproteins / genetics
  • Phosphoproteins / metabolism
  • Primary Cell Culture
  • src-Family Kinases / genetics
  • src-Family Kinases / metabolism

Substances

  • Adaptor Proteins, Signal Transducing
  • Biomarkers
  • Dietary Fats
  • Lat protein, mouse
  • Membrane Proteins
  • Phosphatidylinositol 4,5-Diphosphate
  • Phosphoproteins
  • Sh2d2a protein, mouse
  • Docosahexaenoic Acids
  • src-Family Kinases
  • Phospholipase C delta