The aryl hydrocarbon receptor AhR links atopic dermatitis and air pollution via induction of the neurotrophic factor artemin.

Atopic dermatitis is increasing worldwide in correlation with air pollution. Various organic components of pollutants activate the transcription factor AhR (aryl hydrocarbon receptor). Through the use of AhR-CA mice, whose keratinocytes express constitutively active AhR and that develop atopic-dermatitis-like phenotypes, we identified Artn as a keratinocyte-specific AhR target gene whose product (the neurotrophic factor artemin) was responsible for epidermal hyper-innervation that led to hypersensitivity to pruritus. The activation of AhR via air pollutants induced expression of artemin, alloknesis, epidermal hyper-innervation and inflammation. AhR activation and ARTN expression were positively correlated in the epidermis of patients with atopic dermatitis. Thus, AhR in keratinocytes senses environmental stimuli and elicits an atopic-dermatitis pathology. We propose a mechanism of air-pollution-induced atopic dermatitis via activation of AhR.

Prevalence of Psoriatic Arthritis in Nagano Prefecture, Japan, and Efficacy of the Psoriasis Epidemiology Screening Tool: A Real-World Survey.

Pain, stiffness, and swelling are the main joint symptoms of psoriatic arthritis (PsA); however, they are also common symptoms of other joint diseases. Therefore, it is challenging to distinguish PsA from other joint diseases. To evaluate the prevalence of PsA and the frequency of joint symptoms in psoriasis patients, we conducted a prefecture-wide survey using the Psoriasis Epidemiology Screening Tool (PEST), a patient questionnaire for screening PsA to assess joint symptoms. Data were collected from 764 psoriasis patients, all of whom visited hospitals (55.1%) or clinics (44.9%) in Nagano Prefecture, Japan. The proportion of psoriasis patients with PsA was 6.5% (50 of 764); four patients (1.2%) with PsA were treated in clinics, while 46 patients (10.9%) were treated in hospitals. Based on the responses to the PEST, 18.1% of patients with psoriasis had joint symptoms. In contrast, 73.2% of psoriasis patients with joint symptoms did not have PsA. The PEST showed 52% sensitivity and 93.4% specificity for PsA. In addition, fingernail alterations were common in PsA. The proportion of the population with PsA was lower than reported previously in Japan. This may have been due to the enrollment of a large number of patients treated in clinics. Many patients with PsA were treated at hospitals, which likely reflects the tendency of patients with joint symptoms to receive intensive treatment in hospitals. In addition, based on the lower sensitivity of the PEST in this study, further studies are necessary to establish the validity of the PEST.

Transcription Factors Runx1 and Runx3 Suppress Keratin Expression in Undifferentiated Keratinocytes.

The Runt-related transcription factor (Runx) family has been suggested to play roles in stem cell regulation, tissue development, and oncogenesis in various tissues/organs. In this study, we investigated the possible functions of Runx1 and Runx3 in keratinocyte differentiation. Both Runx1 and Runx3 proteins were detected in primary cultures of mouse keratinocytes. Proteins were localized in the nuclei of undifferentiated keratinocytes but translocated to the cytoplasm of differentiated cells. The siRNA-mediated inhibition of Runx1 and Runx3 expression increased expression of keratin 1 and keratin 10, which are early differentiation markers of keratinocytes. In contrast, overexpression of Runx1 and Runx3 suppressed keratin 1 and keratin 10 expression. Endogenous Runx1 and Runx3 proteins were associated with the promoter sequences of keratin 1 and keratin 10 genes in undifferentiated but not differentiated keratinocytes. In mouse skin, the inhibition of Runx1 and Runx3 expression by keratinocyte-specific gene targeting increased the ratios of keratin 1- and keratin 10-positive cells in the basal layer of the epidermis. On the other hand, inhibition of Runx1 and Runx3 expression did not alter the proliferation capacity of cultured or epidermal keratinocytes. These results suggest that Runx1 and Runx3 likely function to directly inhibit differentiation-induced expression of keratin 1 and keratin 10 genes but are not involved in the regulation of keratinocyte proliferation.

Effect of adalimumab on axial manifestations in Japanese patients with psoriatic arthritis: a 24 week prospective, observational study.

OBJECTIVES: PsA is characterized by enthesitis, synovitis and osseous involvement in the peripheral and axial joints. Few studies have examined axial involvement in PsA using imaging techniques. Here we examined axial involvement in PsA patients using MRI. In addition, we determined the efficacy of 24 week adalimumab treatment in improving the MRI findings of spondylitis and sacroiliitis. METHODS: This was a prospective, open-label, single-arm study in patients with PsA. Adalimumab was administered to patients for a total of 24 weeks. MRI examinations were conducted at baseline and at week 24 of adalimumab treatment. RESULTS: Thirty-seven patients with PsA were included in this study. Spondylitis was observed in at least one site of the positive scan in 91% (n = 31) of patients with PsA. The number of arthritic sites in the cervical, thoracic and lumbar regions of the spine was 48, 67 and 53, respectively. All patients had MRI-determined sacroiliitis of grade ≥1 severity while 28 patients (82%) had grade ≥2 sacroiliitis in at least one sacroiliac region. Sacroiliac arthritis was statistically more severe on the right side than on the left side (P < 0.05). In 34 patients with PsA, the thoracic spine was the most common site of spondylitis. In addition, 24 week adalimumab treatment led to an improvement in the mean number of spondylitis sites and the mean grade of sacroiliitis. CONCLUSION: Treatment with adalimumab for 24 weeks resulted in improvement in spondylitis and sacroiliitis.

Role of Innate Immune Cells in Psoriasis.

Psoriasis is a chronic inflammatory skin condition caused by a combination of hereditary and environmental factors. Its development is closely related to the adaptive immune response. T helper 17 cells are major IL-17-producing cells, a function that plays an important role in the pathogenesis of psoriasis. However, recent findings have demonstrated that innate immune cells also contribute to the development of psoriasis. Innate lymphoid cells, γδ T cells, natural killer T cells, and natural killer cells are activated in psoriasis, contributing to disease pathology through IL-17-dependent and -independent mechanisms. The present review provides an overview of recent findings, demonstrating a role for innate immunity in psoriasis.

Efficacy and safety of adalimumab in Japanese patients with psoriatic arthritis and inadequate response to non-steroidal anti-inflammatory drugs (NSAIDs): A prospective, observational study.

Objectives: To evaluate the efficacy and safety of adalimumab in psoriatic arthritis (PsA) patients in Japan.Methods: In this open-label, single-arm study conducted at six sites from October 2014 to June 2016 (UMIN000016543), PsA patients (≥20 years old) with inadequate response to nonsteroidal anti-inflammatory drugs received adalimumab subcutaneously (80 mg initially, then 40 mg every other week; 24 weeks total). Primary endpoint was American College of Rheumatology 20% improvement (ACR20) response rate at week 12.Results: Of 42 enrolled patients, 37 were treated (mean (SD) age, 56.2 (13.0) years; male, 27 (73.0%)). ACR20, ACR50, and ACR70 response rates were 40.5%, 24.3%, and 16.2% at week 12 and increased to 45.9%, 37.8%, and 21.6% at week 24, respectively. Psoriasis Area and Severity Index (PASI) 50 response rates were unchanged at weeks 12 and 24 (73%), but PASI75 and PASI90 increased from 40.5% and 21.6% to 59.5% and 40.5%, respectively. Other indices such as Physician's Global Assessment score, C-reactive protein-based disease activity score in 28 joints, Bath Ankylosing Spondylitis Disease Activity Index, and serum biomarker levels were significantly improved. No unexpected adverse events were reported.Conclusion: Similar to the global population, adalimumab was efficacious and well tolerated in Japanese treatment-experienced PsA patients.

NRAS mutations in primary and metastatic melanomas of Japanese patients.

BACKGROUND: Characterization of the MAPK signaling pathway in melanoma has led to the development of MEK inhibitors for the treatment of NRAS-mutated melanoma. The success of molecular-targeted therapies underscores the need to identify mutations in target genes. Most of the current data on genetic mutations have been obtained from Caucasian melanoma patients, and screenings of Asian populations are limited. OBJECTIVE: The aim of the present study was to examine NRAS mutations in primary and metastatic lesions of Japanese melanoma patients. METHODS: Clinical melanoma specimens were collected from 127 Japanese patients, including primary (n = 67), metastatic (n = 25) and paired primary and metastatic lesions (n = 35). NRAS mutations in exons 1 and 2 were assessed by polymerase chain reaction and Sanger sequencing. RESULTS: The incidence of NRAS mutations was 7.1 %. NRAS (Q61) was the predominant genetic alteration (77.8 %). NRAS mutations were most frequently detected in acral melanomas (9.3 %), followed by melanomas without chronic sun-induced damage (7.0 %) and mucosal melanomas (4.8 %), and were not detected in melanomas with chronic sun-induced damage. In addition, NRAS mutations were more prevalent in the extremities than in other sites. The NRAS sequence in metastatic lesions did not match that of the primary tumor in one case. CONCLUSION: The frequency of NRAS mutations is lower in the Asian population than in Caucasian patients. The observed heterogeneity of melanoma suggests that genotyping of both primary and metastatic lesions is important to identify candidate patients for molecular-targeted therapies.

Toll-like receptor 4 signaling promotes the migration of human melanoma cells.

Immune cell Toll-like receptors (TLRs) recognize conserved microbial components, leading to immune and inflammatory responses. However, TLRs are also expressed in cancer cells, including melanoma cells, which express TLR2-4. TLR4 ligands have received attention as immunotherapies; therefore, we assessed the expression of TLR4 in human melanoma specimens (29 primary lesions and 28 metastatic lesions) representing different types of melanoma. A high percentage (≥ 90%) of melanoma lesions expressed TLR4, as judged by immunohistochemistry. Next, the role of TLR4 in cell proliferation and migration was assessed using the TLR4-positive (TLR4(+)) melanoma cell lines 501mel and 888mel, and TLR4-negative (TLR4(‒)) 928mel melanoma cells. Lipopolysaccharide (LPS), a TLR4 agonist, increased the proliferation of TLR4(+) melanoma cells but not of TLR4(‒) 928mel cells. The proliferation-inducing effect of LPS in 888mel cells was abolished by blockade of TLR4 signaling via treatment with short interfering RNA (siRNA) targeting TLR4 or myeloid differentiation primary response gene 88 (MyD88), a molecule downstream of TLR4. However, knockdown of TLR4 or MyD88 expression did not affect the LPS-induced proliferation of 501mel cells, suggesting that residual TLR4 signaling is sufficient to maintain cell proliferation. By contrast, LPS increased the migration of TLR4(+) melanoma cells, and this effect was substantially inhibited by TLR4 or MyD88 knockdown. Furthermore, TLR4 knockdown decreased cell migration even in the absence of LPS, suggesting the presence of an endogenous TLR4 ligand(s) in melanoma cells. TLR4 signaling may contribute to melanoma progression, and caution should be exercised when using TLR4 ligands as adjuvant therapy for cancer.

A case of hypocomplementaemic urticarial vasculitis with a high serum level of rheumatoid factor.

We report a case of hypocomplementaemic urticarial vasculitis with an elevated serum rheumatoid factor level. Hypocomplementaemic urticarial vasculitis is an immune complex-mediated disease characterised by urticarial eruptions. High levels of rheumatoid factor may be associated with hypocomplementaemia due to the consumption of complement, because the rheumatoid factor can form immune complexes with immunoglobulin. It is necessary to pay attention to the amounts of complement in cases of urticarial eruptions with elevated rheumatoid factor level. The eruptions were relieved with a combination of prednisolone and colchicine.

Relapse of Palmoplantar Pustulosis Following COVID-19 Vaccination.

Palmoplantar pustulosis (PPP) is a rare chronic pustular condition that affects the palms and soles. Smoking and focal infections and dental metal allergies are risk factors for PPP development. Here we report a case of a 60-year-old woman who experienced a relapse of PPP after receiving the COMIRNATY vaccine against COVID-19. The patient relapsed after being in remission for seven years. This article shows the possible implications of COVID-19 vaccination related to the relapse of previous diseases and stresses the importance of careful observation of post-vaccination occurrences of skin eruptions, especially in patients having a history of PPP.

Bach1-dependent and -independent regulation of heme oxygenase-1 in keratinocytes.

Bach1 is a member of the basic leucine zipper transcription factor family, and the Bach1/small Maf heterodimer specifically represses transcriptional activity directed by the Maf recognition element (MARE). Because Bach1 is a repressor of the oxidative stress response, we examined the function(s) of Bach1 in keratinocytes subjected to oxidative stress. Oxidative stress induced by H(2)O(2) led to an increase in MARE activity and expression of heme oxygenase-1 (HO-1), an inducible antioxidant defense enzyme. Bach1 depletion by small interfering RNAs or by deletion of Bach1 enhanced HO-1 expression in the absence of H(2)O(2), indicating that Bach1 is a critical repressor of HO-1 in keratinocytes. Although Bach1-deficient or -reduced keratinocytes expressed higher levels of HO-1 than control cells in response to H(2)O(2), Bach1 down-regulation did not attenuate the production of reactive oxygen species by H(2)O(2). In contrast, Bach1 overexpression abolished HO-1 induction by H(2)O(2), which led to increased reactive oxygen species accumulation. HO-1 was induced during keratinocyte differentiation, but MARE activity did not change during differentiation. Furthermore, Bach1 overexpression did not inhibit differentiation-associated induction of HO-1 expression, suggesting that HO-1 induction in differentiation is independent of Bach1. Thus, in response to oxidative stress, Bach1 regulates the oxidation state through the negative control of HO-1 expression prior to terminal keratinocyte differentiation. However, Bach1-mediated repression is negated during keratinocyte differentiation.

Increased expression of secreted protein acidic and rich in cysteine and tissue inhibitor of metalloproteinase-3 in epidermotropic melanoma metastasis.

Primary cutaneous melanoma generally arises in the epidermis, followed by invasion into the dermis. Although infrequent, invasive melanoma cells can, alternatively, migrate to the intraepidermal area and form epidermotropic melanoma metastasis (EMM). In this study, we focused on this unique manner of metastasis. To identify the key molecules which affect EMM, gene expression in EMM was compared with that in common skin metastasis (CSM). Polymerase chain reaction (PCR) analysis was performed for genes affecting the extracellular matrix, cellular adhesion, and tumor metastasis on three EMM and three CSM samples as an initial screening. For molecules showing altered expression in the EMM, expression levels were further verified using real-time quantitative PCR (qPCR) and immunohistochemistry. Five molecules showed an expression difference in the initial screening. Among these, secreted protein acidic and rich in cysteine (SPARC) was preferentially expressed in EMM (p = 0.01) by real-time qPCR. Another candidate molecule, tissue inhibitor of metalloproteinase-3 (TIMP3), was not statistically significant (p = 0.07), but showed the tendency of higher expression. These results correlated negatively to expression of N-cadherin and ß-catenin. The upregulation of SPARC and TIMP3 may disrupt the continuity of the canonical Wnt pathway. This pathway regulates adhesion activity of melanoma cells to localize within the dermis, which consequently promotes EMM. Our study highlights the potential role of SPARC and TIMP3 as key molecules in EMM, and analysis of EMM may contribute for understanding melanoma invasion between the epidermis and the dermis.

Influences of p53 deficiency on the apoptotic response, DNA damage removal and mutagenesis in UVB-exposed mouse skin.

p53 suppresses the genomic instability provoked by genotoxic agents. Ultraviolet (UV) B induces skin cancers by producing DNA damage and mutations in the skin genome, whereas the skin tissue responds to the UVB insult with cell cycle arrest and apoptosis as well as damage exclusion by DNA repair. To address the p53 contribution to these skin responses in vivo, we analyzed the time course of DNA damage removal, apoptosis induction and hyperplasia in the skin after UVB irradiation in p53-knockout mice. We also examined UVB-induced mutations in the skin. We found that p53 deficiency does not abolish the UVB-induced apoptotic response in the epidermis but delays the process and the following hyperplasia 12-24 h. Regardless of the p53 genotype, 1 kJ/m(2) UVB induced a total replacement of the epidermal layer by destroying the damaged epidermis by apoptosis and rebuilding a new one through hyperplasia. We failed to detect a clear defect in removal of UVB-induced DNA photolesions from the genome of the p53-deficient skin except for a delay in the epidermis, which seemed to result from the delay in the apoptotic response. However, we found that p53 deficiency enhanced UVB-induced mutagenesis. Furthermore, in a genetic study using Xpa-knockout mice, we showed that the enhanced mutagenic response depends on the activity of nucleotide excision repair (NER), which was also supported by the mutation spectrum observed in the UVB-exposed p53-knockout mice. These results indicate that p53 protects the skin genome from the UVB genotoxicity by facilitating NER, whereas its contribution to the UVB-induced apoptosis is limited.

High commitment of embryonic keratinocytes to terminal differentiation through a Notch1-caspase 3 regulatory mechanism.

Embryonic cells are expected to possess high growth/differentiation potential, required for organ morphogenesis and expansion during development. However, little is known about the intrinsic properties of embryonic epithelial cells due to difficulties in their isolation and cultivation. We report here that pure keratinocyte populations from E15.5 mouse embryos commit irreversibly to differentiation much earlier than newborn cells. Notch signaling, which promotes keratinocyte differentiation, is upregulated in embryonic keratinocyte and epidermis, and elevated caspase 3 expression, which we identify as a transcriptional Notch1 target, accounts in part for the high commitment of embryonic keratinocytes to terminal differentiation. In vivo, lack of caspase 3 results in increased proliferation and decreased differentiation of interfollicular embryonic keratinocytes, together with decreased activation of PKC-delta, a caspase 3 substrate which functions as a positive regulator of keratinocyte differentiation. Thus, a Notch1-caspase 3 regulatory mechanism underlies the intrinsically high commitment of embryonic keratinocytes to terminal differentiation.

Pathogenesis of psoriasis and development of treatment.

The pathogenesis of psoriasis can be explained by dysregulation of immunological cell function as well as keratinocyte proliferation/differentiation. Recently, the immunological pathomechanism has been clarified substantially. Whereas T-helper (Th)1 overactivation was thought to induce occurrence of psoriasis, it has been demonstrated that Th17 cells play a key role. Th17 development is maintained by interleukin (IL)-23 mainly produced by dendritic cells. Th17 cells produce various cytokines, including IL-17A, IL-17F and IL-22. IL-17A and IL-22 induce not only keratinocyte proliferation, but also tumor necrosis factor (TNF)-α, chemokine (C-X-C motif) ligand (CXCL)1 and CXCL8 production. TNF-α accelerates the infiltration of inflammatory cells, including lymphocytes, monocytes and neutrophils, from the peripheral blood into skin with dendritic cell activation. In addition, antimicrobial peptides are overexpressed in psoriatic skin lesions, and the antimicrobial peptide, LL-37, activates dendritic cells, which leads to the development of inflammation. Furthermore, activation of nuclear factor-κB signal induces the expression of keratins 6 and 16 in keratinocytes, which are associated with acanthosis and reduced turnover time in the epidermis. The progression of the pathomechanism contributes to the development of new therapies for psoriasis.

In vasculitis of small muscular arteries, activation of vessel-infiltrating CD8 T cells seems to be antigen-independent.

The etiology of polyarteritis nodosa (PAN) and localized PAN is still unknown, although a T cell-mediated immune mechanism has been considered. CD8 T cells participate not only in the antigen-dependent adaptive immune system, but also in the antigen-independent innate immune system. Non-antigen-activated CD8 T cells express a unique phenotype: granzyme B (GrB) positive /CD25 negative /programmed death-1 (PD-1) negative. The aims of this study were to assess the participation of T cells, especially innate CD8 T cells, in the development of vasculitis. Twenty-eight consecutive cases of skin biopsy specimens with cutaneous vasculitis of small muscular arteries (CVSMA) were retrieved. The series comprises of 21 cases of cutaneous arteritis, three cases of PAN, and four cases of rheumatoid vasculitis. Cases of antineutrophil cytoplasmic antibody-associated vasculitis were excluded. The phenotypes of infiltrating lymphocytes in vasculitis lesions were evaluated by immunohistochemistry. In most cases of CVSMA, the number of CD8 T cells infiltrating the intima was higher than that of CD4 T cells, and significant numbers of GrB-positive cells, which represent activated CD8 T cells, were observed. However, GrB/CD25-double-positive cells, which correspond to antigen-activated T cells, were very few in a small number of cases. Cells positive for PD-1, which is also expressed on antigen-activated CD8 T cells, were not detected. We conclude that a T cell-mediated immune mechanism, involving cytotoxic CD8 T cells, may play a role in the development of CVSMA. Low expression of CD25 in activated CD8 T cells suggests that activation was antigen-independent.

Epidemiological survey of patients with psoriasis in Matsumoto city, Nagano Prefecture, Japan.

A local epidemiological survey of psoriasis was conducted from 19 February to 30 June 2016 in Matsumoto city, Nagano Prefecture, Japan. Patients were predominantly male (268 cases, 71.5% males vs 107 cases, 28.5% females). We estimated that the prevalence of psoriasis was 0.097% in the Matsumoto area. The clinical types of psoriasis identified were psoriasis vulgaris (90.7%), psoriatic arthritis (5.9%), pustular psoriasis (2.1%), guttate psoriasis (1.0%) and psoriatic erythroderma (0.3%). The topical therapeutic agents included corticosteroids (84.0%), vitamin D3 analogs (61.5%), and a combination of calcipotriol and betamethasone dipropionate (31.0%). Current systemic treatments included cyclosporin (9.0%), etretinate (7.4%) and methotrexate (1.3%). Biologic treatments included adalimumab (4.0%), ustekinumab (2.7%), infliximab (1.3%) and secukinumab (0.8%). Ultraviolet B therapy (11.3%) was the predominant phototherapy in which narrow band ultraviolet B therapy accounted for the majority, followed by psoralen and ultraviolet A therapy (1.0%). According to the recent evolution of psoriasis treatment, the use of biologics has been increasing. This study demonstrates the changes of treatment trends of psoriasis in a non-metropolitan regional area.

Eye-open at birth phenotype with reduced keratinocyte motility in LGR4 null mice.

We observed a consistent eye-open at birth (EOB) phenotype in mouse pups homozygous for a leucine-rich repeat containing G-protein coupled receptor 4 (Lgr4) allele deleting the whole transmembrane domain coding region. An in vitro wound-healing scratch assay showed notably reduced keratinocyte motility in the null mice. Phalloidin staining of F-actin in the eyelid epidermis was also reduced. We also generated keratinocyte-specific Lgr4 deficient mice, circumventing the embryonic/neonatal lethality and kidney abnormalities. Most of the conditional Lgr4 knockout mice showed the EOB phenotype. Thus, Lgr4 might be a novel gene class regulating cell motility.