title: Interplay between CXCR2 and BLT1 facilitates neutrophil infiltration and resultant keratinocyte activation in a murine model of imiquimod-induced psoriasis.
abstract: Psoriasis is an inflammatory skin disease with accelerated epidermal cell turnover. Neutrophil accumulation in the skin is one of the histological characteristics of psoriasis. However, the precise mechanism and role of neutrophil infiltration remain largely unknown. In this article, we show that orchestrated action of CXCR2 and leukotriene B4 receptor BLT1 plays a key role in neutrophil recruitment during the development of imiquimod (IMQ)-induced psoriatic skin lesions in mice. Depletion of neutrophils with anti-Ly-6G Ab ameliorated the disease severity, along with reduced expression of proinflammatory cytokine IL-1β in the skin. Furthermore, CXCR2 and BLT1 coordinately promote neutrophil infiltration into the skin during the early phase of IMQ-induced inflammation. In vitro, CXCR2 ligands augment leukotriene B4 production by murine neutrophils, which, in turn, amplifies chemokine-mediated neutrophil chemotaxis via BLT1 in autocrine and/or paracrine manners. In agreement with the increased IL-19 expression in IMQ-treated mouse skin, IL-1β markedly upregulated expression of acanthosis-inducing cytokine IL-19 in human keratinocytes. We propose that coordination of chemokines, lipids, and cytokines with multiple positive feedback loops might drive the pathogenesis of psoriasis and, possibly, other inflammatory diseases as well. Interference to this positive feedback or its downstream effectors could be targets of novel anti-inflammatory treatment.
authors.affiliation: Department of Biochemistry and Molecular Biology, Faculty of Medicine, The University of Tokyo, Bunkyo-ku, Tokyo 113-0033, Japan;
authors.forename: Hayakazu
authors.initials: H
authors.lastname: Sumida
authors.forename: Keisuke
authors.initials: K
authors.lastname: Yanagida
authors.forename: Yoshihiro
authors.initials: Y
authors.lastname: Kita
authors.forename: Jun
authors.initials: J
authors.lastname: Abe
authors.forename: Kouji
authors.initials: K
authors.lastname: Matsushima
authors.forename: Motonao
authors.initials: M
authors.lastname: Nakamura
authors.forename: Satoshi
authors.initials: S
authors.lastname: Ishii
authors.forename: Shinichi
authors.initials: S
authors.lastname: Sato
authors.forename: Takao
authors.initials: T
authors.lastname: Shimizu
mesh_terms: D000276:Adjuvants, Immunologic / Q000633:toxicity; D000634:Aminoquinolines / Q000633:toxicity; D000818:Animals; D002634:Chemotaxis, Leukocyte; D004195:Disease Models, Animal; D000077271:Imiquimod; D007150:Immunohistochemistry; D015603:Keratinocytes / Q000276:immunology / Q000378:metabolism*; D051379:Mice; D018345:Mice, Knockout; D020556:Neutrophil Infiltration / Q000276:immunology*; D009504:Neutrophils / Q000276:immunology; D011565:Psoriasis / Q000139:chemically induced / Q000276:immunology* / Q000378:metabolism; D060888:Real-Time Polymerase Chain Reaction; D023063:Receptors, Interleukin-8B / Q000276:immunology / Q000378:metabolism*; D018102:Receptors, Leukotriene B4 / Q000276:immunology / Q000378:metabolism*
chemical_list: D000276:Adjuvants, Immunologic; D000634:Aminoquinolines; C503704:Ltb4r1 protein, mouse; D023063:Receptors, Interleukin-8B; D018102:Receptors, Leukotriene B4; D000077271:Imiquimod