TPL-2 Regulates Macrophage Lipid Metabolism and M2 Differentiation to Control TH2-Mediated Immunopathology

PLoS Pathog. 2016 Aug 3;12(8):e1005783. doi: 10.1371/journal.ppat.1005783. eCollection 2016 Aug.

Abstract

Persistent TH2 cytokine responses following chronic helminth infections can often lead to the development of tissue pathology and fibrotic scarring. Despite a good understanding of the cellular mechanisms involved in fibrogenesis, there are very few therapeutic options available, highlighting a significant medical need and gap in our understanding of the molecular mechanisms of TH2-mediated immunopathology. In this study, we found that the Map3 kinase, TPL-2 (Map3k8; Cot) regulated TH2-mediated intestinal, hepatic and pulmonary immunopathology following Schistosoma mansoni infection or S. mansoni egg injection. Elevated inflammation, TH2 cell responses and exacerbated fibrosis in Map3k8-/-mice was observed in mice with myeloid cell-specific (LysM) deletion of Map3k8, but not CD4 cell-specific deletion of Map3k8, indicating that TPL-2 regulated myeloid cell function to limit TH2-mediated immunopathology. Transcriptional and metabolic assays of Map3k8-/-M2 macrophages identified that TPL-2 was required for lipolysis, M2 macrophage activation and the expression of a variety of genes involved in immuno-regulatory and pro-fibrotic pathways. Taken together this study identified that TPL-2 regulated TH2-mediated inflammation by supporting lipolysis and M2 macrophage activation, preventing TH2 cell expansion and downstream immunopathology and fibrosis.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Cell Differentiation / genetics
  • Cell Differentiation / immunology*
  • Fibrosis
  • Inflammation / genetics
  • Inflammation / immunology
  • Inflammation / pathology
  • Lipolysis / genetics
  • Lipolysis / immunology*
  • MAP Kinase Kinase Kinases / genetics
  • MAP Kinase Kinase Kinases / immunology*
  • Macrophages / immunology*
  • Macrophages / pathology
  • Mice
  • Mice, Knockout
  • Proto-Oncogene Proteins / genetics
  • Proto-Oncogene Proteins / immunology*
  • Schistosoma mansoni / immunology*
  • Schistosomiasis mansoni / genetics
  • Schistosomiasis mansoni / immunology*
  • Schistosomiasis mansoni / pathology
  • Th2 Cells / immunology*
  • Th2 Cells / pathology

Substances

  • Proto-Oncogene Proteins
  • MAP Kinase Kinase Kinases
  • Map3k8 protein, mouse