Induction of Semaphorin 3A by Resveratrol and Pinostilbene via Activation of the AHR-NRF2 Axis in Human Keratinocytes.

Semaphorin 3A (SEMA3A), a nerve-repellent factor produced by keratinocytes, has an inhibitory effect on nerve extension to the epidermis. Epidermal innervation is involved in pruritus in inflammatory skin diseases such as atopic dermatitis (AD) and dry skin. We previously reported that tapinarof, a stilbene molecule, upregulates SEMA3A in human keratinocytes. We also showed that this mechanism is mediated via the aryl hydrocarbon receptor (AHR), a ligand-activated transcription factor, and the nuclear factor erythroid 2-related factor 2 (NRF2) axis. Since some stilbenes activate AHR and NRF2, we attempted to identify other stilbenes that upregulate SEMA3A. We analyzed normal human epidermal keratinocytes (NHEKs) treated with 11 types of stilbenes and examined SEMA3A expression. We found that resveratrol and pinostilbene, antioxidant polyphenols, upregulated SEMA3A and increased nuclear AHR and NRF2 expression. In addition, AHR knockdown by small interfering RNA (siRNA) transfection abolished the NRF2 nuclear expression. Furthermore, AHR and NRF2 knockdown by siRNA transfection abrogated resveratrol- and pinostilbene-induced SEMA3A upregulation. Finally, we confirmed that resveratrol and pinostilbene increased SEMA3A promoter activity through NRF2 binding using ChIP-qPCR analysis. These results suggest that resveratrol and pinostilbene upregulate SEMA3A via the AHR-NRF2 axis in human keratinocytes.

Human epidermal growth factor receptor 3 serves as a novel therapeutic target for acral melanoma.

Acral melanoma (AM) is a rare, life-threatening skin cancer. Since AM bears unique features, existing therapies for other types of malignant melanomas have limited effects and the establishment of effective treatments for AM is strongly desired. Human epidermal growth factor receptor 3 (HER3) is a receptor tyrosine kinase that is frequently elevated in tumors and contributes to tumor progression, so it is considered a promising therapeutic target for tumors. This study was established to evaluate the potential of HER3-targeted therapy to treat AM by investigating the expression and function of HER3. HER3 expression was immunohistochemically analyzed in AM lesions of 72 patients and in AM cell lines. To investigate function of HER3, effects of HER3 inhibition on cell proliferation, apoptosis/survival, anchorage-independent growth, and underlying signals were assessed. HER3 was expressed in patients' AM tissues with various intensities and HER3 expression was significantly correlated with patient's disease-free survival. In vitro analyses revealed that HER3 is more highly expressed in AM cells than in normal epidermal melanocytes. AM cells were also shown to be sensitive to the cytotoxic part of a HER3-targeted antibody-drug conjugate. Inhibition of HER3 did not affect cell proliferation, whereas it decreased the anchorage-independent growth of AM cells likely through affecting the nuclear translocation of Yes-associated protein. It is implied that HER3 may serve as a novel therapeutic target for AM.

Metalloproteinase 1 downregulation in neurofibromatosis 1: Therapeutic potential of antimalarial hydroxychloroquine and chloroquine.

Neurofibromatosis type 1 is an autosomal dominant genetic disorder caused by mutation in the neurofibromin 1 (NF1) gene. Its hallmarks are cutaneous findings including neurofibromas, benign peripheral nerve sheath tumors. We analyzed the collagen and matrix metalloproteinase 1 (MMP1) expression in Neurofibromatosis 1 cutaneous neurofibroma and found excessive expression of collagen and reduced expression of MMP1. To identify new therapeutic drugs for neurofibroma, we analyzed phosphorylation of components of the Ras pathway, which underlies NF1 regulation, and applied treatments to block this pathway (PD184352, U0126, and rapamycin) and lysosomal processes (chloroquine (CQ), hydroxychloroquine (HCQ), and bafilomycin A (BafA)) in cultured Neurofibromatosis 1 fibroblasts. We found that downregulation of the MMP1 protein was a key abnormal feature in the neurofibromatosis 1 fibroblasts and that the decreased MMP1 was restored by the lysosomal blockers CQ and HCQ, but not by the blockers of the Ras pathway. Moreover, the MMP1-upregulating activity of those lysosomal blockers was dependent on aryl hydrocarbon receptor (AHR) activation and ERK phosphorylation. Our findings suggest that lysosomal blockers are potential candidates for the treatment of Neurofibromatosis 1 neurofibroma.

Aryl Hydrocarbon Receptor and Dioxin-Related Health Hazards-Lessons from Yusho.

Poisoning by high concentrations of dioxin and its related compounds manifests variable toxic symptoms such as general malaise, chloracne, hyperpigmentation, sputum and cough, paresthesia or numbness of the extremities, hypertriglyceridemia, perinatal abnormalities, and elevated risks of cancer-related mortality. Such health hazards are observed in patients with Yusho (oil disease in Japanese) who had consumed rice bran oil highly contaminated with 2,3,4,7,8-pentachlorodibenzofuran, polychlorinated biphenyls, and polychlorinated quaterphenyls in 1968. The blood concentrations of these congeners in patients with Yusho remain extremely elevated 50 years after onset. Dioxins exert their toxicity via aryl hydrocarbon receptor (AHR) through the generation of reactive oxygen species (ROS). In this review article, we discuss the pathogenic implication of AHR in dioxin-induced health hazards. We also mention the potential therapeutic use of herbal drugs targeting AHR and ROS in patients with Yusho.

Cancer- and noncancer-specific cumulative incidence of death after exposure to polychlorinated biphenyls and dioxins: A competing risk analysis among Yusho patients.

BACKGROUND: In competing risks settings, the cause-specific cumulative incidence function is of great interest since it quantifies cumulative risk in the presence of other causes. To date, however, long-term cancer- and noncancer-specific mortality in Yusho patients exposed to polychlorinated biphenyls (PCBs) and dioxin-related compounds has not been estimated. METHODS: We identified vital status and cause of death for Yusho patients between 1968 and 2017. Risk of cancer- and noncancer-specific mortality was estimated using a flexible hazards-based regression model, with accounting for competing events. RESULTS: In total, 1664 Yusho patients with 63,566 person-years of follow-up were included in the analysis. 50-year cumulative incidence of cancer mortality was 12.4% (95% confidence interval [CI], 10.5-14.7) in males and 4.7% (95% CI, 3.5-6.4) in females (difference, 7.7 percentage points [95% CI, 5.2-10.2]; adjusted hazard ratio for males, 2.61 [95% CI, 1.93-3.52]). For noncancer, the 50-year cumulative incidence of mortality was 35.4% (95% CI, 32.8-38.3) in males and 35.6% (95% CI, 33.3-38.1) in females (difference, -0.2 percentage points [95% CI, -3.5 to 3.1]; adjusted hazard ratio for males, 1.51 [95% CI, 1.26-1.82]). CONCLUSIONS: These findings confirm that male Yusho patients have a significantly higher risk of cumulative incidence of cancer-specific mortality than female Yusho patients. Our findings might be useful in providing Yusho patients with more accurate information on cancer prognosis and survivorship and help determine more appropriate disease management.

Mortality in Yusho patients exposed to polychlorinated biphenyls and polychlorinated dibenzofurans: a 50-year retrospective cohort study.

BACKGROUND: In 1968, the Yusho incident resulted in accidental exposure to polychlorinated biphenyls (PCBs), polychlorinated dibenzofurans (PCDFs), and related compounds in Japan. This study updated the risk of mortality in Yusho patients. METHODS: We obtained updated cohort data for all Yusho patients for the period 1968-2017. We calculated standardized mortality ratios (SMRs) for all-cause and cause-specific mortality over a 50-year follow-up period compared with the general population in Japan. RESULTS: A total of 1664 Yusho patients with 63,566 person-years of follow up were included in the analysis. Among males, excess mortality was observed for all cancers (SMR: 1.22, 95% confidence interval [CI]: 1.02 to 1.45) and lung cancer (SMR: 1.59, 95% CI: 1.12 to 2.19). Among females, increased mortality was observed for liver cancer (SMR: 2.05, 95% CI: 1.02 to 3.67). No significant increase was seen in non-cancer-related mortality compared with the general population. CONCLUSIONS: Carcinogenic risk in humans after exposure to PCBs and PCDFs remains higher among Yusho patients. Our findings suggest the importance of care engagement and optimum management to deal with the burden of Yusho disease.

Interleukin-17A and Keratinocytes in Psoriasis.

The excellent clinical efficacy of anti-interleukin 17A (IL-17A) biologics on psoriasis indicates a crucial pathogenic role of IL-17A in this autoinflammatory skin disease. IL-17A accelerates the proliferation of epidermal keratinocytes. Keratinocytes produce a myriad of antimicrobial peptides and chemokines, such as CXCL1, CXCL2, CXCL8, and CCL20. Antimicrobial peptides enhance skin inflammation. IL-17A is capable of upregulating the production of these chemokines and antimicrobial peptides in keratinocytes. CXCL1, CXCL2, and CXCL8 recruit neutrophils and CCL20 chemoattracts IL-17A-producing CCR6+ immune cells, which further contributes to forming an IL-17A-rich milieu. This feed-forward pathogenic process results in characteristic histopathological features, such as epidermal hyperproliferation, intraepidermal neutrophilic microabscess, and dermal CCR6+ cell infiltration. In this review, we focus on IL-17A and keratinocyte interaction regarding psoriasis pathogenesis.

The EGFR-ERK/JNK-CCL20 Pathway in Scratched Keratinocytes May Underpin Koebnerization in Psoriasis Patients.

Epidermal keratinocytes represent a rich source of C-C motif chemokine 20 (CCL20) and recruit CCR6+ interleukin (IL)-17A-producing T cells that are known to be pathogenic for psoriasis. A previous study revealed that scratch injury on keratinocytes upregulates CCL20 production, which is implicated in the Koebner phenomenon characteristically seen in psoriasis patients. However, the molecular mechanisms leading to scratch-induced CCL20 production remain elusive. In this study, we demonstrate that scratch injury upregulates the phosphorylation of epidermal growth factor receptor (EGFR) and that the specific EGFR inhibitor PD153035 attenuates scratch-induced CCL20 upregulation in an extracellular signal-related kinase (ERK)-dependent, and to a lesser extent, a c-Jun N-terminal kinase (JNK)-dependent but p38 mitogen-activated protein kinase (MAPK)-independent manner. Immunoreactive CCL20 was visualized in the keratinocytes that lined the scratched wound. IL-17A also induced the phosphorylation of EGFR and further augmented scratch-induced CCL20 upregulation. The EGFR-ERK/JNK-CCL20 pathway in scratched keratinocytes may explain why Koebnerization is frequently seen in psoriasis patients.

A case of overlapping adult-onset linear scleroderma and Parry-Romberg syndrome presenting with widespread ipsilateral neurogenic involvement.

Linear scleroderma is a variant of localized scleroderma. We report a 43-year-old woman who had developed left arm weakness and linear scleroderma on her back during pregnancy at 25 years of age, followed by left hemifacial atrophy and left leg weakness. She had multiple linear scleroderma lesions on her trunk and left limbs, left eyelid ptosis, impairment of vertical movement and abduction of the left eye, left hemifacial atrophy, and weakness and atrophy of the sternocleidomastoid, trapezius, and proximal limb muscles on the left side. On serology, antibodies to U1-ribonucleoprotein and Jo-1 were positive; anti-scleroderma-70 antibody was negative. Skin biopsy demonstrated increased hypertrophic collagen fibers without inflammatory infiltrates. Needle electromyography of left limb muscles revealed mild neurogenic patterns; left quadriceps muscle biopsy showed chronic neurogenic changes. Brain magnetic resonance imaging revealed mild left hemispheric atrophy. This is a rare case of linear scleroderma and Parry-Romberg syndrome presenting with widespread ipsilateral neurogenic manifestations.

A Case of Atrophic Dermatofibroma Overexpressing Matrix Metalloproteinase-1.

This case report describes the importance of considering this tumor as one of the differential diagnoses when we encounter a flat and/or atrophic and depressible lesion in the upper portion of the trunk.

Serum squamous cell carcinoma antigen (SCCA)-2 correlates with clinical severity of pediatric atopic dermatitis in Ishigaki cohort.

BACKGROUND: We sometimes encounter difficulties in assessing the severity of pediatric atopic dermatitis (AD) using currently available biomarkers such as thymus and activation-regulated chemokine (TARC) due to the higher baseline values in non-AD children. Recent case control studies have indicated the usefulness of squamous cell carcinoma antigens (SCCAs) in pediatric and adult AD. Notably, SCCAs are induced by IL-4 and IL-13, vital Th2 cytokines that play important roles in AD etiology. OBJECTIVES: Relatively low prevalence and mild disease severity of pediatric AD are observed in our Ishigaki cohort presumably due to the moisturising subtropical climate, which could conversely mean possible higher allergic potential of non-AD subjects towards AD. Thus, the purpose of this study was to further investigate the feasibility of using SCCAs together with TARC and periostin as biomarkers for pediatric AD even in the Ishigaki cohort. METHODS: We enrolled 1459 nursery school children and identified 96 as having AD through 2009-2011. As statistical analyses, we performed Student's t-test, correlation analysis, and receiver and operating characteristic (ROC) analysis. RESULTS: Serum SCCA1, SCCA2, periostin and TARC levels were all significantly increased in AD compared with those in non-AD, but only serum SCCA2 showed a significant increase in AD when assessed in each age group or in subgroup analysis. Among the biomarkers tested, serum SCCA2 also showed the best correlations with clinical AD severity and TARC and showed the best diagnosability for AD in ROC analysis. CONCLUSIONS: SCCA2 is a potent biomarker for pediatric AD in the Ishigaki cohort.

Platinum and palladium nanoparticle-containing mixture, PAPLAL, does not induce palladium allergy.

Palladium (Pd) is a common metal found in jewellery and dental appliances, but it has been shown to be likely to cause metal allergy. We previously reported that platinum (nPt) and palladium (nPd) nanoparticle-containing mixture (PAPLAL) has both superoxide dismutase and catalase activities and that the topical application of PAPLAL improved skin atrophy induced by chronic oxidative damage in an ageing mouse model. However, the safety of PAPLAL for preventing Pd allergy remains unclear. In the present study, we investigated whether or not PAPLAL induces Pd allergy. We found that PAPLAL treatment caused no skin inflammation, while nPd administration caused only slight skin inflammation compared to the palladium chloride-induced severe reaction in an experimental metal allergy model. A gene expression analysis revealed that PAPLAL treatment significantly suppressed the expression of Inf-γ, Il-1ß and Tnfα genes. Even in human clinical trials using patches containing metal nanoparticles, nPd and PAPLAL failed to induce significant skin inflammation. These results suggest that mixing with nPt in PAPLAL suppresses the inflammation response of nPd. PAPLAL can be expected to be applied to various skin treatments as a safe topical substance.

Pathogenesis of Atopic Dermatitis: Current Paradigm.

Atopic dermatitis (AD) is characterized by skin inflammation, barrier dysfunction and chronic pruritus. In this review, recent advances in the pathogenesis of AD are summarized. Clinical efficacy of the anti-IL-4 receptor antibody dupilumab implies that type 2 cytokines IL-4 and IL-13 have pivotal roles in atopic inflammation. The expression of IL-4 and IL-13 as well as type 2 chemokines such as CCL17, CCL22 and CCL26 is increased in the lesional skin of AD. In addition, IL-4 and IL-13 down-regulate the expression of filaggrin in keratinocytes and exacerbate epidermal barrier dysfunction. Keratinocytes in barrier-disrupted epidermis produce large amounts of thymic stromal lymphopoietin, IL-25 and IL-33, conducing to type 2 immune deviation via OX40L/OX40 signaling. IL-31, produced by type 2 T cells, is a cardinal pruritogenic cytokine. IL-4 and IL-13 also amplify the IL-31-mediated sensory nerve signal. These molecules are particularly important targets for future drug development for AD.

Cyto/chemokine profile of in vitro scratched keratinocyte model: Implications of significant upregulation of CCL20, CXCL8 and IL36G in Koebner phenomenon.

BACKGROUND: Scratch injury induces Koebner phenomenon in psoriasis. Smoking is also a risk factor for psoriasis. Keratinocytes can produce various psoriasis-related molecules including TNF, IL1 A, IL1B, IL6, IL12B, IL17C, IL23 A, IL36 A, IL36B, IL36 G, CXCL1, CXCL2, CXCL8, CXCL9, CXCL10, CCL20, IFNB, and CAMP. However, the scratch-induced molecular profiling remains elusive. OBJECTIVE: To profile the induction pattern of above-mentioned psoriasis-related and keratinocyte-derived molecules by scratch injury in the presence or absence of anti-psoriatic drugs or benzo[a]pyrene, a major environmental pollutant of tobacco smoke. METHODS: Confluent normal human keratinocytes were scratched and molecules were assayed by qRT-PCR, ELISA and Western blotting with or without drugs and benzo[a]pyrene. RESULTS: Among the 18 molecules, the scratch injury on a confluent keratinocyte sheet significantly and selectively upregulated the mRNA expression of four cyto/chemokines, CXCL8, CCL20, IL36G, and TNF, in a scratch-line-number-dependent manner under either low- or high-calcium condition. However, significant protein secretion was only demonstrated for CXCL8 and CCL20. The IL36 G protein was not secreted, but its intracellular level was significantly upregulated by scratch injury, whereas neither the secretion nor the intracellular level of TNF protein was affected by scratch injury. Dexamethasone, but not maxacalcitol nor the phosphodiesterase 4 inhibitor apremilast, partially inhibited the CXCL8 and CCL20 secretion. Benzo[a]pyrene significantly and synergistically enhanced the scratch-induced CCL20 secretion that may explain why smoking is a risk factor for psoriasis. CONCLUSION: CCL20 and to a less extent CXCL8 may play a key role in triggering the Koebner phenomenon after scratch injury to keratinocytes.

Psoriasis and the TNF/IL23/IL17 axis.

The excellent response of psoriasis to anti-TNF-α(TNF)/IL23/IL17A biologics implies a crucial role for the TNF/IL23/IL17 axis in developing psoriasis. In addition to the TNF/IL23/IL17 axis provided by immune cells, current evidence points to an important contribution of TNF, IL23 and IL17C produced from non-hematopoietic keratinocytes. Therefore, crosstalk between immune cells and keratinocytes forms a multilayered feed-forward loop to accelerate the TNF/IL23/IL17A axis. Many biologics have already been licensed or are under clinical trials. Given that the IL-17 signature is more upregulated in the skin than in synovium in psoriatic arthritis, anti-IL-23/IL-17 agents seem to be superior to anti-TNF-α remedies in the treatment of skin lesions. In this review, we summarize recent topics in psoriasis and the TNF/IL23/IL17 axis.