PAR-1 signaling on macrophages is required for effective in vivo delayed-type hypersensitivity responses
Hannah Wilkinson,
Hugh Leonard,
Daxin Chen,
Toby Lawrence,
Michael Robson,
Pieter. Goossens,
John H. McVey,
Anthony Dorling
Affiliations
Hannah Wilkinson
Department of Inflammation Biology, School of Immunology & Microbial Sciences, King's College London, Guy's Hospital, London SE1 9RT, UK; Corresponding author
Hugh Leonard
Department of Inflammation Biology, School of Immunology & Microbial Sciences, King's College London, Guy's Hospital, London SE1 9RT, UK
Daxin Chen
Department of Inflammation Biology, School of Immunology & Microbial Sciences, King's College London, Guy's Hospital, London SE1 9RT, UK
Toby Lawrence
Centre for Inflammation Biology and Cancer Immunology, School of Immunology & Microbial Sciences, King's College London, London SE1 9RT, UK
Michael Robson
Department of Inflammation Biology, School of Immunology & Microbial Sciences, King's College London, Guy's Hospital, London SE1 9RT, UK
Pieter. Goossens
Department of Pathology, Cardiovascular Research Institute Maastricht (CARIM), Maastricht University, 6229HX Maastricht, the Netherlands
John H. McVey
School of Bioscience & Medicine, Faculty of Health and Medical Sciences, University of Surrey, Guildford GU2 7XH, UK
Anthony Dorling
Department of Inflammation Biology, School of Immunology & Microbial Sciences, King's College London, Guy's Hospital, London SE1 9RT, UK; Corresponding author
Summary: Delayed-type hypersensitivity (DTH) responses underpin chronic inflammation. Using a model of oxazolone-induced dermatitis and a combination of transgenic mice, adoptive cell transfer, and selective agonists/antagonists against protease activated receptors, we show that that PAR-1 signaling on macrophages by thrombin is required for effective granuloma formation. Using BM-derived macrophages (BMMs) in vitro, we show that thrombin signaling induced (a) downregulation of cell membrane reverse cholesterol transporter ABCA1 and (b) increased expression of IFNγ receptor and enhanced co-localization within increased areas of cholesterol-rich membrane microdomains. These two key phenotypic changes combined to make thrombin-primed BMMs sensitive to M1 polarization by 1000-fold less IFNγ, compared to resting BMMs. We confirm that changes in ABCA1 expression were directly responsible for the exquisite sensitivity to IFNγ in vitro and for the impact on granuloma formation in vivo. These data indicate that PAR-1 signaling plays a hitherto unrecognized and critical role in DTH responses.
