Lymphoid tissue phospholipase A2 group IID resolves contact hypersensitivity by driving antiinflammatory lipid mediators

J Exp Med. 2013 Jun 3;210(6):1217-34. doi: 10.1084/jem.20121887. Epub 2013 May 20.

Abstract

Resolution of inflammation is an active process that is mediated in part by antiinflammatory lipid mediators. Although phospholipase A2 (PLA2) enzymes have been implicated in the promotion of inflammation through mobilizing lipid mediators, the molecular entity of PLA2 subtypes acting upstream of antiinflammatory lipid mediators remains unknown. Herein, we show that secreted PLA2 group IID (PLA2G2D) is preferentially expressed in CD11c(+) dendritic cells (DCs) and macrophages and displays a pro-resolving function. In hapten-induced contact dermatitis, resolution, not propagation, of inflammation was compromised in skin and LNs of PLA2G2D-deficient mice (Pla2g2d(-/-)), in which the immune balance was shifted toward a proinflammatory state over an antiinflammatory state. Bone marrow-derived DCs from Pla2g2d(-/-) mice were hyperactivated and elicited skin inflammation after intravenous transfer into mice. Lipidomics analysis revealed that PLA2G2D in the LNs contributed to mobilization of a pool of polyunsaturated fatty acids that could serve as precursors for antiinflammatory/pro-resolving lipid mediators such as resolvin D1 and 15-deoxy-Δ(12,14)-prostaglandin J2, which reduced Th1 cytokine production and surface MHC class II expression in LN cells or DCs. Altogether, our results highlight PLA2G2D as a "resolving sPLA2" that ameliorates inflammation through mobilizing pro-resolving lipid mediators and points to a potential use of this enzyme for treatment of inflammatory disorders.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Anti-Inflammatory Agents / immunology*
  • Anti-Inflammatory Agents / metabolism
  • Dendritic Cells / enzymology
  • Dendritic Cells / immunology
  • Dendritic Cells / metabolism
  • Dermatitis, Contact / enzymology
  • Dermatitis, Contact / immunology*
  • Dermatitis, Contact / metabolism
  • Fatty Acids, Unsaturated / immunology
  • Fatty Acids, Unsaturated / metabolism
  • Group II Phospholipases A2 / immunology
  • Group II Phospholipases A2 / metabolism*
  • Humans
  • Immunologic Factors / immunology*
  • Immunologic Factors / metabolism
  • Inflammation / enzymology
  • Inflammation / immunology
  • Inflammation / metabolism
  • Lipids / immunology*
  • Lymphoid Tissue / enzymology
  • Lymphoid Tissue / immunology*
  • Lymphoid Tissue / metabolism
  • Macrophages / enzymology
  • Macrophages / immunology
  • Macrophages / metabolism
  • Male
  • Mice
  • Mice, Inbred C57BL
  • Mice, Transgenic
  • Phosphatidylethanolamines / immunology
  • Phosphatidylethanolamines / metabolism
  • Skin / enzymology
  • Skin / immunology
  • Skin / metabolism

Substances

  • Anti-Inflammatory Agents
  • Fatty Acids, Unsaturated
  • Immunologic Factors
  • Lipids
  • Phosphatidylethanolamines
  • phosphatidylethanolamine
  • Group II Phospholipases A2
  • Pla2g2d protein, mouse