2015CB910403), and National Natural Science Foundation of China (81570118, 81570112). Data Availability All relevant data are within the paper.. last, PD 151746 HLCL-61 (calpain-1 inhibitor) treatment decreased epidermal thickness in imquimod-induced psoriasis model. Taken together, our results suggest that mature IL-1 induced by hS100A7 is usually via RAGE-p38 MAPK and calpain-1 pathway in keratinocyte and this mechanism may play an important role during psoriasis. Introduction Psoriatic skin lesions major feature increased keratinocyte proliferation and abnormal differentiation. The immunopathogenesis involves a dysregulated conversation between epidermal keratinocytes and infiltrating inflammatory cells. The pro-inflammatory cytokine interleukin-1 is constitutively expressed by keratinocytes and has been shown to be expressed in psoriatic lesional skin. Treatment of wild-type organotypic cultures with interleukin-1 was sufficient to induce hyperkeratosis in an model of lamellar ichthyosis. IL-1 is likely to be an important mediator in the initiation and maintenance of psoriatic plaques and may represent an attractive therapeutic target.[5C7] It has been reported that proteolysis of IL-1 by calpain-1 results in a several-fold increase in bioactivity, which has nearly 50-fold higher affinity for IL-1R than full-length IL-1. Increased HLCL-61 IL-1 activity is a hallmark of many chronic inflammatory conditions, including rheumatoid arthritis, diabetes, atherosclerosis, and psoriasis.[9, 10] hS100A7 (psoriasin) belongs to the S100A family of Ca2+-binding proteins, it has been reported with many functions, such as antimicrobial, chemotactic activity,[12, 13] and associated with some diseases, such as psoriasis, HLCL-61 skin tumors,[15, 16] atopic dermatitis, and chronic rhinosinusitis. These conditions are characterized by an inflammatory reaction, suggesting the role of hS100A7 in the regulation of inflammation. Our study for the first time reveals that hS100A7 induces mature IL-1 expression and other downstream signaling molecules and Reverse Reverse Reverse Reverse Reverse Reverse m18S Forward Reverse IL-17a neutralization 100 g of monoclonal mouse IL-17a antibody (R&D, MAB421) was intradermally injected into mouse back skin 24 hrs before experiment. Then imiquimod was injected, mouse skin was taken for analysis of mS100a7a15 expression 3 days later. Statistical analysis Two-tailed t-test was used to determine significances between two groups. The significances among multiple groups were determined by One-way ANOVA with GraphPad 5 (San Diego, CA). For all those statistical assessments, we considered values 0.05 to be statistically significant. Results hS100A7 induces mature IL-1 expression in normal human epidermal keratinocytes IL-1 processing by multiple immune-related proteases can act as a switch to enhance the proinflammatory properties of this cytokine. In our study, IL-1 and IL-1 mRNA levels were measured by real time CEACAM3 PCR. The results exhibited that hS100A7 treatment in keratinocyte induced IL-1 mRNA expression, but it cant induce IL-1 mRNA expression (Fig 1A). IL-1 (17 kDa), not IL-1 (17 kDa), is usually induced by the treatment of hS100A7 in normal human keratinocytes (Fig 1B and 1C). The concentration of HLCL-61 IL-1 in cell supernatant is also increased after hS100A7 treatment (Fig 1D). We also show that mature IL-1a is usually increased in psoriatic epidermis (Fig 1E). These data demonstrate that hS100A7 induce mature IL-1 (17 kDa) production in keratinocytes. Open in a separate windows Fig 1 hS100A7 induces mature IL-1 expression in normal human epidermal keratinocytes.(A) IL-1 and IL-1 mRNA levels were measured by real time PCR after incubated with indicated concentrations hS100A7 at 6 hours. (B) Immunoblot of IL-1 treated with hS100A7 (50 ng/ml) at 6 hours or recombinant IL-1 protein (30 ng) by western blot in NHEKs. (C) Immunoblot of IL-1 treated with hS100A7 (50 ng/ml) at 6 hours or irradiated with broad-band UVB 4 mW/cm2 by western blot in NHEKs. (D) NHEK cells were incubated with hS100A7 (50 ng/ml) and concentrations of IL-1 in the supernatants were determined by ELISA after 5 hours. (E) Psoriatic epidermis was extracted by RAPI lysis buffer, IL-1 protein level was determined by western blot. All data are representative of three impartial experiments with n = 3 and are means SEM. values were determined by two-tailed t test. *** values were determined by two-tailed t test. *** values were determined by two-tailed t test. HLCL-61 *** values were determined by one-way ANOVA. n.s., no significance. * and and and values were determined by two-tailed t test or one-way ANOVA. * em P /em 0.05, *** em P /em 0.001. Discussion This study exhibited that hS100A7 treatment lead to mature IL-1 production in keratinocytes via RAGE-p38 MAPK-calpain-1 signaling. Several psoriasis-related cytokines, including IL-17a, IL-22  and IL-36, could up-regulate hS100A7 expression in keratinocytes. IL-17a neutralizing.