Short ragweed pollen promotes M2 macrophage polarization via TSLP/TSLPR/OX40L signaling in allergic inflammation

Mucosal Immunol. 2019 Sep;12(5):1141-1149. doi: 10.1038/s41385-019-0187-8. Epub 2019 Jul 26.

Abstract

This study was to explore the role and mechanism of macrophages in pollen-triggered allergic inflammation. A murine model of short ragweed (SRW) pollen-induced experimental allergic conjunctivitis (EAC), and bone marrow (BM)-macrophages cultures were used. Typical allergic manifestations and TSLP-stimulated Th2 hyperresponse were observed in ocular surface of EAC model in wild-type (WT) mice induced by SRW. The M2 phenotype markers, Arg1, Ym1 and FIZZ1, were highly expressed by conjunctiva and draining cervical lymph nodes (CLNs) of WT-EAC mice when compared with controls, as evaluated by RT-qPCR and Immunofluorescent double staining with macrophage marker F4/80. The stimulated expression of TSLPR and OX40L by macrophage was detected in conjunctiva and CLNs by RT-qPCR, double staining, and flow cytometry. M2 macrophages were found to produce TARC and MDC. In contrast, EAC model with TSLPR-/- mice did not show allergic signs and any increase of Th2 cytokines (IL-4, IL-5 and IL-13) and M2 markers. In vitro cultures confirmed that SRW extract stimulates expression of TSLPR, OX40L, TARC, MDC, and three M2 markers by BM-macrophages from WT mice, but not from TSLPR-/- mice. These findings demonstrate that SRW pollen primes macrophage polarization toward to M2 phenotype via TSLP/TSLPR/OX40L signaling to amplify allergic inflammation.

Publication types

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

MeSH terms

  • Animals
  • Antigens, Plant / immunology*
  • Biomarkers
  • Cytokines / metabolism
  • Disease Models, Animal
  • Hypersensitivity / immunology*
  • Hypersensitivity / metabolism*
  • Immunoglobulins / metabolism
  • Macrophage Activation / immunology*
  • Macrophages / immunology*
  • Macrophages / metabolism*
  • Mice
  • Mice, Knockout
  • OX40 Ligand / metabolism
  • Phenotype
  • Plant Extracts / immunology*
  • Receptors, Cytokine / metabolism
  • Signal Transduction*
  • Th2 Cells / immunology
  • Th2 Cells / metabolism
  • Thymic Stromal Lymphopoietin

Substances

  • Antigens, Plant
  • Biomarkers
  • Cytokines
  • Immunoglobulins
  • OX40 Ligand
  • Plant Extracts
  • Receptors, Cytokine
  • Tslpr protein, mouse
  • ragweed pollen
  • Thymic Stromal Lymphopoietin
  • TSLP protein, mouse