Exacerbation and Prolongation of Psoriasiform Inflammation in Diabetic Obese Mice: A Synergistic Role of CXCL5 and Endoplasmic Reticulum Stress  Noriko Shimoura, Hiroshi Nagai, Susumu Fujiwara, Haruki Jimbo, Chikako Nishigori  Journal of Investigative Dermatology  Volume 138, Issue 4, Pages 854-863 (April 2018) DOI: 10.1016/j.jid.2017.10.023 Copyright © 2017 The Authors Terms and Conditions

Figure 1 Imiquimod (IMQ)-induced psoriasis-like dermatitis is exacerbated and prolonged in db/db mice. IMQ cream was applied on the back skin on days 0 and 1. (a) Images of IMQ-induced dermatitis. (b) Erythema and scaling of the affected area were scored. (c) Representative images of hematoxylin and eosin staining of lesional skin tissues. (d) Epidermal thickness. (e) Immune cell infiltration was scored on a scale from 0 to 4 (0: none; 1: minimal; 2: weak; 3: moderate; 4: strong). The cumulative score (dermis plus subcutaneous tissue) is depicted. (f) Munro’s microabscess formation was scored on a scale from 0 to 4 (0: none; 1: precious few; 2: few; 3: many; 4: great many). Data shown represent mean ± standard error of mean and were derived from one of three individual experiments. Journal of Investigative Dermatology 2018 138, 854-863DOI: (10.1016/j.jid.2017.10.023) Copyright © 2017 The Authors Terms and Conditions

Figure 2 Expression of Cxcl5 and Il-1b is remarkably elevated in db/db mice compared to that in C57BL/6 mice and m+/db mice. The mRNA expression levels of Cxcl1, Cxcl5, Il-1b, Ly6g, and Il-17 were determined by real-time quantitative reverse transcriptase PCR and normalized to Gapdh mRNA levels. Relative expression levels (mean ± standard error of mean) are shown; ∗P < 0.05, ∗∗P < 0.01. Journal of Investigative Dermatology 2018 138, 854-863DOI: (10.1016/j.jid.2017.10.023) Copyright © 2017 The Authors Terms and Conditions

Figure 3 Expression of psoriasis-related cytokines and chemokines is significantly elevated in db/db mice compared to C57BL/6 and m+/db mice. The mRNA expression levels of Cxcl1, Cxcl5, Il-1b, Ly6g, Il-17, Tnf, Il-6, Il-12p40, Il-23p19, Il-22, Cxcl10, Ccl2, Adipoq, Lep, and Retn were determined by real-time quantitative reverse transcriptase PCR and normalized to Gapdh mRNA levels. Relative expression levels (mean ± standard error of mean) are shown; ∗P < 0.05, ∗∗P < 0.01. Journal of Investigative Dermatology 2018 138, 854-863DOI: (10.1016/j.jid.2017.10.023) Copyright © 2017 The Authors Terms and Conditions

Figure 4 CXCL5+ Ly6G+ inflammatory cells markedly infiltrate the lesions of IMQ-induced dermatitis in db/db mice but not in m+/db mice. Histopathological findings of day 3 lesions of IMQ-induced dermatitis in db/db (a, c, e, g, and i−n) and m+/db (b, d, f, h) mice. (a, b) Hematoxylin and eosin stain. (c, d) Immunostaining for CXCL5, (e, f) CXCL1, and (g, h) IL-1β. In (c), arrows and arrowheads indicate CXCL5+ inflammatory cells that infiltrate the dermis and subcutaneous tissues, respectively. (i, k) Immunostaining for CXCL5 and (j, l) Ly6G on serial sections (i−j and k−l). (m) Single-color immunostaining for Ly6G (red color) and (n) two-color immunostaining for Ly6G (red color) and CXCL5 (green color) were conducted on serial sections (m, n). Notably, a lot of double-positive cells in (n) were colored dark-purple. Scale bars = 50 μm. Journal of Investigative Dermatology 2018 138, 854-863DOI: (10.1016/j.jid.2017.10.023) Copyright © 2017 The Authors Terms and Conditions

Figure 5 In vivo treatment with anti-Gr1 antibody caused a marked suppression of imiquimod (IMQ)-induced dermatitis in db/db mice, accompanied by decreased infiltration of CXCL5+ cells and IL-1β+ cells. IMQ was applied on days 0 and 1, as described in Materials and Methods. Anti-Gr1 (1,000 μg) or control rat IgG was injected intraperitoneally on days −1, 1, and 2. (a) Images of IMQ-induced dermatitis in db/db mice on day 3. (b) Hematoxylin and eosin staining and immunostaining for (c) IL-1β and (d) CXCL5 on day 3 tissues of IMQ-induced dermatitis in db/db mice. Scale bars = 100 μm. Journal of Investigative Dermatology 2018 138, 854-863DOI: (10.1016/j.jid.2017.10.023) Copyright © 2017 The Authors Terms and Conditions

Figure 6 CXCL5 induces secretion of IL-1β from macrophages and endoplasmic reticulum stress enhances IL-1β secretion. (a) Relative Grp78/Bip mRNA expression levels in skin tissues of m+/db and db/db mice. (b) Immunostaining for F4/80, (c) IL-1β, and (d) GRP78/Bip on serial sections from day 3 tissues of imiquimod-induced dermatitis in db/db mice. Scale bars = 100 μm. Arrowheads in (b) indicate F4/80+ macrophages in subcutaneous tissues. Arrows in (c) and (d) indicate IL-1β+ and GRP78/Bip+ vessels, respectively, in subcutaneous tissues. (e) Levels of the IL-1β protein in the culture supernatants of lipopolysaccharide (100 ng/ml)-primed THP1 macrophages and (f) primary human monocytes/macrophages incubated with CXCL5 with or without palmitic acid (PA) for 24 hours. Values are mean ± standard error of mean; ∗P < 0.05, ∗∗P < 0.01. TUDCA, tauroursodeoxycholic acid. Journal of Investigative Dermatology 2018 138, 854-863DOI: (10.1016/j.jid.2017.10.023) Copyright © 2017 The Authors Terms and Conditions