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Background Atopic dermatitis (AD) patients have a barrier disorder in association with Th2 dominant skin inflammation. Galectin‐7 (Gal‐7), a soluble unglycosylated lectin, is highly expressed in the stratum corneum of AD patients. However, the biological significance of increased Gal‐7 expression in AD skin lesions remains unclear. Objective We aimed to investigate the production mechanism and functional role of Gal‐7 in AD patients and IL‐4/IL‐13–stimulated epidermal keratinocytes. Methods We assessed the Gal‐7 expression levels in skin lesions and sera from AD patients. Gal‐7 levels were also measured in monolayered normal human epidermal keratinocytes (NHEKs) and 3‐dimensional (3D)–reconstructed epidermis in the presence or absence of IL‐4/IL‐13 with or without Stat3, Stat6 or Gal‐7 gene silencing. Results Gal‐7 was highly expressed in the stratum corneum or intercellular space of AD lesional epidermis as assessed by the stratum corneum proteome analysis and immunohistochemistry. A positive correlation was noted between serum Gal‐7 level and transepidermal water loss in patients with AD. These clinical findings were corroborated by our in vitro data, which showed that IL‐4/IL‐13 facilitated the extracellular release of endogenous Gal‐7 in both monolayered NHEKs and 3D‐reconstructed epidermis. This machinery was caused by IL‐4/IL‐13–induced cell damage and inhibited by knockdown of Stat6 but not Stat3 in NHEKs. Moreover, we performed Gal‐7 knockdown experiment on 3D‐reconstructed epidermis and the result suggested that endogenous Gal‐7 serves as a protector from IL‐4/IL‐13–induced disruption of cell‐to‐cell adhesion and/or cell‐to‐extracellular matrix adhesion. Conclusion and Clinical Relevance Our study unveils the characteristic of Gal‐7 and its possible role as an alarmin that reflects the IL‐4/IL‐13–induced skin barrier impairment in AD.

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An epidemiological study found that higher frequencies of carbonylated proteins (CPs) in corneocytes are closely correlated with the loss of skin hydration. On the other hand, a high frequency of CPs in reconstructed human epidermal equivalents (RHEEs) exposed to low humidity at their surface was also observed according to the generation of reactive oxygen species. Although those results elucidated the relationship between skin hydration and protein oxidation in the stratum corneum, it did not identify whether CPs are a trigger in the loss of skin hydration or are end-products of skin dryness. Thus, we conducted the following studies to identify the roles of CPs in skin hydration. In the skin, it has been demonstrated that acrolein initiates protein carbonylation in corneocytes. The transepidermal water loss (TEWL) in porcine skin and in RHEEs treated with acrolein were examined. TEWL values were higher depending on the frequency of protein carbonylation in the stratum corneum. Furthermore, the contact angles of carbonylated skin against water became lower. Those facts indicated that protein carbonylation is one of the triggers in the disruption of barrier function, and skin carbonylated with acrolein showed a hydrophilic property compared with non-treated skin. We hypothesized that the modification of functional groups (e.g. -SH, NH 2 and COOH) in proteins during carbonylation induced structural alterations of those proteins in corneocytes. COOH group levels in corneocytes increased depending on the frequency of protein carbonylation, which suggested that aldehyde groups increased by the carbonylation process are further oxidized to COOH. Summarizing these results, we propose that the change of protein characteristics from hydrophobic to hydrophilic is one possible factor involved in the disruption of protein carbonylation-induced barrier function. 323Natural antioxidant products from peanuts sprouts and citron seed oils exhibit a potent anti-inflammatory activity in the oxazolone-induced contact dermatitis model in vivo (the Republic of) Background: In our previous study, natural products of ethanol extract peanut sprouts (EPS) and citron seed oils (CSO) were found to have potent antioxidant activity in vitro cultured cells of HaCaT. Objective: This study was aimed to evaluate whether the mixture of 5% EPS and CSO (EPS/CSO) ointment had an anti-inflammatory activity through anti-oxidant action in the oxazolone (OX)-induced inflammatory model in vivo. Methods: For valuating skin inflammation in vivo, inflammation degree was measured by scoring erythema and scaling as well as histological studies (H & E and immunohistochemistry), Also, biochemical experiments on biomarkers for type 2 skin inflammation (TSLP, IL-33, and IL-25), neurogenic inflammation (NGF and CGRP) and skin barrier (filaggrin) were performed with skin extracts of OX-treated hairless mice. Results: The scores of erythema and scaling were increased in the OX-treated mice, which were markedly decreased by the application of EPS/CSO ointment for 2 we...

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