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.[1] The immunopathogenesis involves a dysregulated conversation between epidermal keratinocytes and infiltrating inflammatory cells.[2] The pro-inflammatory cytokine interleukin-1 is constitutively expressed by keratinocytes and has been shown to be expressed in psoriatic lesional skin.[3] Treatment of wild-type organotypic cultures with interleukin-1 was sufficient to induce hyperkeratosis in an model of lamellar ichthyosis.[4] 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.[8] 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,[11] chemotactic activity,[12, 13] and associated with some diseases, such as psoriasis,[14] HLCL-61 skin tumors,[15, 16] atopic dermatitis,[17] and chronic rhinosinusitis.[18] 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.[21] 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 [34] and IL-36[35], could up-regulate hS100A7 expression in keratinocytes. IL-17a neutralizing.