Publications by authors named "Koji Sayama"

Background: Interleukin (IL)-23 is involved in the pathogenesis of ulcerative colitis (UC). A genome-wide significant association between IL23R p.G149R (rs76418789) and UC was previously identified in Japan and Korea.

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Background And Aim: Although diet is one of the potential environmental factors affecting ulcerative colitis (UC), evidence is not sufficient to draw definitive conclusions. This Japanese case-control study examined the association between the consumption of coffee, other caffeine-containing beverages and food, and total caffeine and the risk of UC.

Methods: The study involved 384 UC cases and 665 control subjects.

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Nuclear IL-33 levels are high at the epidermal edges of skin wounds and facilitate wound healing. However, IL-33-mediated regulation of keratinocyte (KC) biology during wound healing remains poorly understood. During skin-wound healing, KC migration and re-epithelialization are mediated predominantly by EGFR signaling activation and depend on the function of signal transducer and activator of transcription 3 (STAT3).

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Speckle-type pox virus and zinc finger (POZ) protein (SPOP), a substrate recognition receptor for the cullin-3/RING ubiquitin E3 complex, leads to the ubiquitination of >40 of its target substrates. Since a variety of point mutations in the substrate-binding domain of SPOP have been identified in cancers, including prostate and endometrial cancers, the pathological roles of those cancer-associated SPOP mutants have been extensively elucidated. In this study, we evaluated the cellular functions of wild-type SPOP in non-cancerous human keratinocyte-derived HaCaT cells expressing wild-type SPOP gene.

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Article Synopsis
  • Trehalose, a disaccharide of glucose, enhances the spread of the epidermal layer in living skin equivalents (LSE) without adverse effects when applied to human fibroblasts.
  • RNA-seq analysis showed that trehalose treatment activates the CDKN1A pathway, impacting various factors related to cell behavior and growth.
  • Application of trehalose-treated fibroblasts in wound healing significantly improved closure and capillary formation in experimental mice, with the effects dependent on the CDKN1A pathway, suggesting potential therapeutic benefits for wound repair.
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Article Synopsis
  • Self-healing collodion baby (SHCB) is a rare, mild form of congenital ichthyosis where skin scaling improves significantly in the first year of life, but can be hard to distinguish from other forms during infancy.
  • The study reports two Japanese SHCB patients with specific mutations in the CYP4F22 gene, which plays a crucial role in skin lipid production essential for maintaining skin barrier function.
  • Researchers found that SHCB patients had lower levels of important skin ceramides compared to parents and non-SHCB individuals, and suggest that genetic testing and skin sample analysis could help in the early diagnosis of congenital ichthyoses.
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Background: The interleukin (IL)-23/Th17 pathway plays a critical role in ulcerative colitis (UC). The IL-12p40 subunit, which is shared by IL-23 and IL-12, is encoded by the IL12B gene. The current case-control study investigated the association between IL12B SNP rs6887695 and the UC risk.

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Various epidermal growth factor receptor (EGFR) ligands are highly expressed in the epidermis of psoriasis lesions, and abnormal EGFR activation appears to be involved in the pathogenesis of psoriasis. However, how EGFR signaling contributes to the development of psoriasis is unclear. Interleukin (IL)-17A, a critical effector of the IL-23/IL-17A pathway, increases the expression of psoriasis signature genes in keratinocytes and plays an essential role in the pathogenesis of psoriasis by inducing IκBζ, a critical transcriptional regulator in psoriasis.

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Herein, we discuss a new pyrene-based push-pull dye (PC) and our investigation of its photophysical properties and applicability to biological studies. The newly synthesized dye exhibits highly polarity-sensitive fluorescence over a significantly wide range (, the green to far-red region), accompanied by high fluorescence quantum yields ( > 0.70 in most organic solvents) and superior photostability to that of the commonly used Nile Red (NR) dye, which also fluoresces in the green to red region.

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Atopic dermatitis (AD) is an inflammatory skin disease characterized by skin barrier dysfunction. Although T helper type 2 cytokines downregulate the expression of epidermal barrier proteins, the signaling mechanism underlying these effects remains unclear. IL-33, a chromatin-associated cytokine, is highly expressed in the nuclei of epidermal keratinocytes in AD skin; however, it is unclear whether this expression promotes the development of AD.

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Senescence is a fate-determined state, accompanied by reorganization of heterochromatin. Although lineage-appropriate genes can be temporarily repressed through facultative heterochromatin, stable silencing of lineage-inappropriate genes often involves the constitutive heterochromatic mark, histone H3 lysine 9 trimethylation (H3K9me3). The fate of these heterochromatic genes during senescence is unclear.

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Generalized pustular psoriasis (GPP) is characterized by acute flare-ups induced by various factors, but few reports have described GPP onset or flare-up induced by vaccination. To our knowledge, only three such cases following coronavirus disease 2019 (COVID-19) vaccination have been reported. We herein report a case of GPP flare-up after COVID-19 mRNA vaccination.

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Background And Aim: Although an inverse relationship between current smoking and the development of ulcerative colitis (UC) has been shown in North America and Europe, evidence is limited in Asian countries, where the incidence of UC is rapidly increasing. This Japanese case-control study examined the association between active and passive smoking and risk of UC.

Methods: A self-administered questionnaire was used to obtain information on smoking and potential confounding factors in 384 cases with a diagnosis of UC within the past 4 years and 665 controls.

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Skin regenerative capacity declines with age, but the underlying mechanisms are largely unknown. Here we demonstrate a functional link between epidermal growth factor receptor (EGFR) signaling and type XVII collagen (COL17A1) proteolysis on age-associated alteration of keratinocyte stem cell dynamics in skin regeneration. Live-imaging and computer simulation experiments predicted that human keratinocyte stem cell motility is coupled with self-renewal and epidermal regeneration.

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IL-33, a chromatin-associated multifunctional cytokine, is implicated in the pathogenesis of atopic dermatitis (AD), an inflammatory skin disorder characterized by skin barrier dysfunction. IL-33 accumulates in the nuclei of epidermal keratinocytes (KCs) in AD lesions. However, it is unclear whether nuclear IL-33 directly contributes to the pathogenesis of AD.

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Objectives: Oxidative stress is considered one of the etiologic factors involved in ulcerative colitis (UC), yet there is limited epidemiologic information regarding the relationship between antioxidant intake and the risk of UC. The aim of the present case-control study in Japan was to examine the association between intake of green and yellow vegetables, other vegetables, fruit, vitamin C, vitamin E, retinol, alpha-carotene, beta-carotene, and cryptoxanthin and UC risk.

Methods: A total of 384 cases within 4 y of diagnosis with UC and 665 controls were included in the study.

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Pemphigoid vegetans is a rare variant of bullous pemphigoid characterized by vegetative and purulent lesions of the groin, axillae, thighs, hands, eyelids, and perioral regions. The clinical features and histological findings of pemphigus vegetans and immunohistochemical characteristics of bullous pemphigoid are shown. An 86-year-old woman presented with vegetative lesions in the vulva and groin, and blisters on the head, neck, axillae, and thighs.

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