title: A novel role of hepatocyte growth factor as an immune regulator through suppressing dendritic cell function.
abstract: Hepatocyte growth factor (HGF) plays an important role in many biological events such as angiogenesis, cell proliferation, anti-fibrosis and antiapoptosis. It is well known that HGF promotes tumor progression and suppresses development of fibrosis after tissue injury. In contrast, its role in immune-mediated disorders has not been fully clarified. In the present study, we examined the role of HGF in Ag-specific immune response using in vitro studies and an experimental model of allergic airway inflammation. We first confirmed that dendritic cells (DCs) expressed the receptor for HGF, c-met, which was not expressed in T cells. Treatment with HGF both in vitro and in vivo potently suppressed DC functions such as Ag-presenting capacity, thus down-regulating Ag-induced Th1- and Th2-type immune responses. Exogenous administration of the HGF expression plasmid into Ag-primed mice markedly suppressed the development of airway eosinophilia and airway hyperresponsiveness, which was induced by Ag inhalation, with suppression of the Ag-presenting capacity of DCs in the lung. HGF exhibited these immunosuppressive effects without up-regulation of IL-10 or TGF-beta. We also found that expression of endogenous HGF in the lung significantly increased following Ag sensitization and inhalation challenges. Finally, neutralization of endogenous HGF in vivo significantly increased airway eosinophilia and airway hyperresponsiveness with up-regulation of the Ag-presenting capacity of DCs in the lung. These results demonstrated a novel, significant, and possibly therapeutic role of HGF as a potent regulator in immune-mediated disorders such as asthma.
authors.affiliation: Pulmonary Division, Department of Allergy and Rheumatology, Graduate School of Medicine, University of Tokyo, Tokyo, Japan.
authors.forename: Katsuhide
authors.initials: K
authors.lastname: Okunishi
authors.forename: Makoto
authors.initials: M
authors.lastname: Dohi
authors.forename: Kazuyuki
authors.initials: K
authors.lastname: Nakagome
authors.forename: Ryoichi
authors.initials: R
authors.lastname: Tanaka
authors.forename: Shinya
authors.initials: S
authors.lastname: Mizuno
authors.forename: Kunio
authors.initials: K
authors.lastname: Matsumoto
authors.forename: Jun-Ichi
authors.initials: J
authors.lastname: Miyazaki
authors.forename: Toshikazu
authors.initials: T
authors.lastname: Nakamura
authors.forename: Kazuhiko
authors.initials: K
authors.lastname: Yamamoto
mesh_terms: D000818:Animals; D017951:Antigen Presentation / Q000502:physiology; D002478:Cells, Cultured; D003713:Dendritic Cells / Q000276:immunology*; D015536:Down-Regulation / Q000276:immunology; D018014:Gene Transfer Techniques; D017228:Hepatocyte Growth Factor / Q000097:blood / Q000235:genetics / Q000502:physiology*; D007166:Immunosuppressive Agents / Q000097:blood / Q000494:pharmacology; D008168:Lung / Q000166:cytology / Q000276:immunology / Q000378:metabolism; D008297:Male; D051379:Mice; D008807:Mice, Inbred BALB C; D010047:Ovalbumin / Q000276:immunology; D012130:Respiratory Hypersensitivity / Q000276:immunology; D013601:T-Lymphocytes / Q000276:immunology; D015854:Up-Regulation / Q000276:immunology
chemical_list: D007166:Immunosuppressive Agents; D017228:Hepatocyte Growth Factor; D010047:Ovalbumin