"Input/output cytokines" in epidermal keratinocytes and the involvement in inflammatory skin diseases.

Considering the role of epidermal keratinocytes, they occupy more than 90% of the epidermis, form a physical barrier, and also function as innate immune barrier. For example, epidermal keratinocytes are capable of recognizing various cytokines and pathogen-associated molecular pattern, and producing a wide variety of inflammatory cytokines, chemokines, and antimicrobial peptides. Previous basic studies have shown that the immune response of epidermal keratinocytes has a significant impact on inflammatory skin diseases. The purpose of this review is to provide foundation of knowledge on the cytokines which are recognized or produced by epidermal keratinocytes. Since a number of biologics for skin diseases have appeared, it is necessary to fully understand the relationship between epidermal keratinocytes and the cytokines. In this review, the cytokines recognized by epidermal keratinocytes are specifically introduced as "input cytokines", and the produced cytokines as "output cytokines". Furthermore, we also refer to the existence of biologics against those input and output cytokines, and the target skin diseases. These use results demonstrate how important targeted cytokines are in real skin diseases, and enhance our understanding of the cytokines.

Co-occurrence of non-alcoholic steatohepatitis exacerbates psoriasis associated with decreased adiponectin expression in a murine model.

Introduction: Clinical studies have suggested a bidirectional association between non-alcoholic steatohepatitis (NASH) and psoriasis, affecting each other's development and severity. Here, we explored bidirectional causal linkages between NASH and psoriasis using a murine model. Methods: NASH was induced in mice by streptozotocin injection at 2 days of age and by high-fat diet feeding (STAM™ model). Psoriasis was induced by topical application of imiquimod (IMQ) on the ear. The severities of liver damage and psoriatic skin changes were determined using histological analysis. Gene expression in the skin tissues was evaluated using quantitative PCR analysis. Serum cytokine levels were determined using enzyme-linked immunosorbent assay. To examine the innate immune responses of normal human epidermal keratinocytes (NHEKs), the cells were treated with interleukin (IL)-17A, tumor necrosis factor (TNF)-α, and AdipoRon, an adiponectin receptor agonist. Results and Discussion: There were no differences in the degree of liver tissue damage (fat deposition, inflammation, and fibrosis) between NASH mice with and those without psoriasis. Conversely, the co-occurrence of NASH significantly augmented psoriatic skin changes, represented by epidermal hyperplasia, in psoriatic mice. Pro-inflammatory cytokines were expressed in the inflamed skin of psoriatic mice, and the expression of genes, especially Il23a, Il1b, Il36g, and Mip2, was significantly upregulated by the co-occurrence of NASH. The expression of keratinocyte activation marker genes Defb4b and Krt16 was also upregulated by the co-occurrence of NASH. The serum TNF-α and IL-17 levels were increased by the co-occurrence of NASH and psoriasis. The serum adiponectin levels decreased in NASH mice compared with that in non-NASH mice. In NHEK culture, TNF-α and IL-17A synergistically upregulated CXCL1, CXCL8, and IL1B expression. The upregulated pro-inflammatory gene expression was suppressed by AdipoRon treatment, reflecting the anti-inflammatory capacity of adiponectin. Conclusion: The co-occurrence of NASH exacerbated psoriatic skin changes associated with increased serum inflammatory cytokine levels and decreased serum adiponectin levels. Combined with in vitro findings, increased inflammatory cytokine levels and decreased adiponectin levels likely promote innate immune responses in epidermal keratinocytes in psoriatic skin lesions. Overall, therapeutic intervention for co-occurring NASH is essential to achieve a favorable prognosis of psoriasis in clinical practice.

Imatinib has minimal effects on inflammatory and osteopenic phenotypes in a murine cherubism model.

OBJECTIVE: Cherubism is a genetic disorder characterised by bilateral jawbone deformation. The associated jawbone lesions regress after puberty, whereas severe cases require surgical treatment. Although several drugs have been tested, fundamental treatment strategies for cherubism have not been established. The effectiveness of imatinib has recently been reported; however, its pharmaceutical mechanism remains unclear. In this study, we tested the effects of imatinib using a cherubism mouse model. METHODS: We used Sh3bp2 P416R cherubism mutant mice, which exhibit systemic organ inflammation and osteopenia. The effects of imatinib were determined using primary bone marrow-derived macrophages. Imatinib was administered intraperitoneally to the mice, and serum tumour necrosis factor-α (TNFα), organ inflammation and bone properties were examined. RESULTS: The cherubism mutant macrophages produced higher levels of TNFα in response to lipopolysaccharide compared to wild-type macrophages, and imatinib did not significantly suppress TNFα production. Although imatinib suppressed osteoclast formation in vitro, administering it in vivo did not suppress organ inflammation and osteopenia. CONCLUSION: The in vivo administration of imatinib had a minimal therapeutic impact in cherubism mutant mice. To establish better pharmaceutical interventions, it is necessary to integrate new findings from murine models with clinical data from patients with a definitive diagnosis of cherubism.

Summary of the current status of clinically diagnosed cases of Schnitzler syndrome in Japan.

BACKGROUND: Schnitzler syndrome is a rare disorder with chronic urticaria, and there is no report summarizing the current status in Japan. METHODS: A nationwide survey of major dermatology departments in Japan was conducted in 2019. We further performed a systematic search of PubMed and Ichushi-Web, using the keywords "Schnitzler syndrome" and "Japan" then contacted the corresponding authors or physicians for further information. RESULTS: Excluding duplicates, a total of 36 clinically diagnosed cases were identified from 1994 through the spring of 2022, with a male to female ratio of 1:1. The median age of onset was 56.5 years. It took 3.3 years from the first symptom, mostly urticaria, to reach the final diagnosis. The current status of 30 cases was ascertained; two patients developed B-cell lymphoma. SchS treatment was generally effective with high doses of corticosteroids, but symptoms sometimes recurred after tapering. Colchicine was administered in 17 cases and was effective in 8, but showed no effect in the others. Tocilizumab, used in six cases, improved laboratory abnormalities and symptoms, but lost its efficacy after several years. Rituximab, used in five cases, was effective in reducing serum IgM levels or lymphoma mass, but not in inflammatory symptoms. Four cases were treated with IL-1 targeting therapy, either anakinra or canakinumab, and achieved complete remission, except one case with diffuse large B-cell lymphoma. CONCLUSIONS: Since Schnitzler syndrome is a rare disease, the continuous collection and long-term follow-up of clinical information is essential for its appropriate treatment and further understanding of its pathophysiology.

TRAPS mutations in Tnfrsf1a decrease the responsiveness to TNFα via reduced cell surface expression of TNFR1.

Tumor necrosis factor (TNF) receptor-associated periodic syndrome (TRAPS) is an autoinflammatory periodic fever syndrome associated with heterozygous mutations in TNFRSF1A, which encodes TNF receptor type I (TNFR1). Although possible proinflammatory mechanisms have been proposed, most previous studies were performed using in vitro overexpression models, which could lead to undesirable inflammatory responses due to artificial overexpression. It is crucial to reproduce heterozygous mutations at physiological expression levels; however, such studies remain limited. In this study, we generated TRAPS mutant mice and analyzed their phenotypes. Three Tnfrsf1a mutant strains were generated by introducing T79M, G87V, or T90I mutation. T79M is a known mutation responsible for TRAPS, whereas G87V is a TRAPS mutation that we have reported, and T90I is a variant of unknown significance. Using these murine models, we investigated whether TRAPS mutations could affect the inflammatory responses in vivo and in vitro. We found that none of the mutant mice exhibited detectable inflammatory phenotypes under standard housing conditions for 1 year. Interestingly, TRAPS mutant (T79M and G87V) mice had reduced mortality rates after the administration of lipopolysaccharide (LPS) and D-galactosamine, which induce TNFα-dependent lethal hepatitis. Moreover, TRAPS mutations strongly suppressed the development of TNFα-mediated arthritis when crossed with human TNFα transgenic mice. In in vitro primary bone marrow-derived macrophage cultures, the T79M and G87V mutations attenuated the inflammatory responses to TNFα compared with the wild-type, whereas these mutations did not alter the responsiveness of these cells to LPS. The T90I mutant macrophages behaved similarly to wild type in response to LPS and TNFα. The TNFR1 levels were increased in whole-cell lysates of TRAPS mutant macrophages, whereas the cell surface expression of TNFR1 was significantly decreased in TRAPS mutant macrophages. Taken together, TRAPS mutations did not augment the inflammatory responses to TNFα and LPS; instead, they suppressed the response to TNFα via decreased cell surface expression of TNFR1. The stimulation of lymphotoxin-α, adenosine triphosphate, and norepinephrine in primary macrophages or various stimuli in murine splenocytes did not induce detectable inflammatory responses. In conclusion, TRAPS mutations suppressed responsiveness to TNFα, and TRAPS-associated inflammation is likely induced by unconfirmed disease-specific proinflammatory factors.

Obesity and Dyslipidemia Synergistically Exacerbate Psoriatic Skin Inflammation.

Patients with psoriasis are frequently complicated with metabolic syndrome; however, it is not fully understood how obesity and dyslipidemia contribute to the pathogenesis of psoriasis. To investigate the mechanisms by which obesity and dyslipidemia exacerbate psoriasis using murine models and neonatal human epidermal keratinocytes (NHEKs), we used wild-type and Apoe-deficient dyslipidemic mice, and administered a high-fat diet for 10 weeks to induce obesity. Imiquimod was applied to the ear for 5 days to induce psoriatic dermatitis. To examine the innate immune responses of NHEKs, we cultured and stimulated NHEKs using IL-17A, TNF-α, palmitic acid, and leptin. We found that obesity and dyslipidemia synergistically aggravated psoriatic dermatitis associated with increased gene expression of pro-inflammatory cytokines and chemokines. Treatment of NHEKs with palmitic acid and leptin amplified pro-inflammatory responses in combination with TNF-α and IL-17A. Additionally, pretreatment with palmitic acid and leptin enhanced IL-17A-mediated c-Jun N-terminal kinase phosphorylation. These results revealed that obesity and dyslipidemia synergistically exacerbate psoriatic skin inflammation, and that metabolic-disorder-associated inflammatory factors, palmitic acid, and leptin augment the activation of epidermal keratinocytes. Our results emphasize that management of concomitant metabolic disorders is essential for preventing disease exacerbation in patients with psoriasis.

IL-17A promotes vascular calcification in an ex vivo murine aorta culture.

BACKGROUND: Vascular calcification is characterized by mineral deposition in the vasculature, which is triggered by chronic systemic inflammation, including psoriasis. Psoriasis is an IL-17A-mediated inflammatory skin disease that is associated with exacerbated vascular calcification and high cardiovascular mortality. Although previous studies have shown that IL-17A induces vascular dysfunction in murine psoriasis models, it has not been clarified whether IL-17A induces vascular calcification. In this study, we investigated the potential vascular calcification-inducing effect of IL-17A in an ex vivo culture system. METHODS: Thoracic and abdominal aortas from mice were cultured in a medium supplemented with inorganic phosphate and were treated with inflammatory cytokines (IL-1ß, TNF-α, IL-6, and IL-17A). Vascular calcification was determined using micro-computed tomography (CT) and histological analyses. RESULTS: IL-1ß, TNF-α, and IL-6 did not significantly promote vascular calcification, whereas IL-17A significantly accelerated vascular calcification of the aorta, as indicated by the increased mineralized volume based on micro-CT analysis. Micro-CT and histological analyses also revealed that the promoting effect of IL-17A on vascular calcification was concentration dependent. CONCLUSIONS: IL-17A significantly promoted vascular calcification in ex vivo cultured aortas, which suggests that this mechanism is involved in the increased risk of cardiovascular events in IL-17A-mediated inflammatory diseases.

The "Ant-farm"-like Appearance of Restricted Lower Limb Vasculitis on Fluorodeoxyglucose-positron Emission Tomography.

Restricted lower limb vasculitis is a type of localized muscle vasculitis limited to the lower limbs. The usefulness of fluorodeoxyglucose-positron emission tomography (FDG-PET) for the diagnosis of this entity has not yet been reported. We herein report three patients with a fever and persistent lower limb pain. FDG-PET revealed linear and patchy FDG uptakes in their lower limbs. Combined with magnetic resonance imaging and histological findings, they were diagnosed with lower limb vasculitis. Linear and patchy FDG uptakes are considered to reflect the presence of muscle vasculitis. The characteristic "ant-farm"-like FDG-PET images can be a diagnostic clue for the currently overlooked vasculitis.

Barium-induced pneumatosis intestinalis in a patient with anti-synthetase syndrome.

Pneumatosis intestinalis is defined as the presence of gas in the bowel wall. The combination of the two risks, pre-existing connective tissue diseases and barium contrast examination, may trigger pneumatosis intestinalis, albeit at a low incidence. Clinicians should be aware of the condition for proper differential diagnosis.

Purple urine bags reflecting an aging society.

The purple urine bag syndrome is an underrecognized but quite common condition, resulting in marked discoloration of the urine bag system due to bacterial metabolism. This syndrome is associated with advanced age and bedridden persons.

SH3BP2 Deficiency Ameliorates Murine Systemic Lupus Erythematosus.

BACKGROUND: The adaptor protein Src homology 3 domain-binding protein 2 (SH3BP2) is widely expressed in immune cells. It controls intracellular signaling pathways. The present study was undertaken to investigate the role of SH3BP2 in a murine systemic lupus erythematosus model. METHODS: For the lupus model, we used Faslpr/lpr mice. Clinical and immunological phenotypes were compared between Faslpr/lpr and SH3BP2-deficient Faslpr/lpr mice. Splenomegaly and renal involvement were assessed. Lymphocyte subsets in the spleen were analyzed by flow cytometry. To examine the role of SH3BP2 in specific cells, B cell-specific SH3BP2-deficient lupus mice were analyzed; T cells and bone marrow-derived dendritic cells and macrophages were analyzed in vitro. RESULTS: SH3BP2 deficiency significantly reduced lupus-like phenotypes, presented as splenomegaly, renal involvement, elevated serum anti-dsDNA antibody, and increased splenic B220+CD4-CD8- T cells. Notably, SH3BP2 deficiency in B cells did not rescue the lupus-like phenotypes. Furthermore, SH3BP2 deficiency did not substantially affect the characteristics of T cells and macrophages in vitro. Interestingly, SH3BP2 deficiency suppressed the differentiation of dendritic cells in vitro and reduced the number of dendritic cells in the spleen of the lupus-prone mice. CONCLUSIONS: SH3BP2 deficiency ameliorated lupus-like manifestations. Modulating SH3BP2 expression could thus provide a novel therapeutic approach to autoimmune diseases.

In vivo analysis of thrombus formation in arthritic mice.

OBJECTIVES: Rheumatoid arthritis (RA) is characterized by inflammation in multiple joints. In addition to causing joint destruction, the persistent systemic inflammation with RA increases the risk of cardiovascular disease. Although there are in vitro studies showing the prothrombotic effect of inflammatory cytokines, especially TNF, in vivo experimental evidence is lacking due to the complexity of in vivo modeling and observation. In this study, we aimed to model in vivo thrombus formation in arthritic mice and to determine whether the arthritic condition would further promote thrombotic formation. METHODS: Human TNF-transgenic mice were used as the arthritis model. Thrombus formation was observed on the testicular arterioles. Thrombus formation was induced by reactive oxygen species generated from hematoporphyrin under laser irradiation. RESULTS: Platelet thrombus formation was observed in real-time using a laser confocal microscopy in both wild-type and arthritic mice. Quantitative analyses revealed that no significant differences were observed in thrombus formation, represented by platelet attachment time and vascular obstruction time, in our experimental setting. CONCLUSION: Although we confirmed the usefulness of this novel technique for in vivo studies, further investigation is required to conclude the possible mechanism of prothrombotic phenotypes under inflammatory conditions.

Tattoo skin reaction as a skin manifestation of systemic sarcoidosis.

A 41-year-old man presented with itching of the skin surrounding his tattoos, blurred vision, fever, general fatigue, and arthralgia. Physical examination revealed skin bulges confined to the tattoo ink lines. Histological analyses of the skin revealed non-caseating granulomas surrounding the tattoo inks. Together with other clinical manifestations including uveitis, lymph nodes swelling, and elevated serum angiotensin-converting enzyme and lysozyme, he was diagnosed with systemic sarcoidosis. The administration of prednisolone alleviated the sarcoidosis-related symptoms, including skin changes. This case illustrates that skin changes on tattoos can be a presenting manifestation of systemic sarcoidosis and that skin biopsy is useful in early diagnosis.

Severe oral stomatitis due to reactivation of herpes simplex virus type 1 in a methotrexate-treated patient with dermatomyositis.

We herein report a case of a 79-year-old Japanese woman who developed severe oral stomatitis during methotrexate (MTX) treatment for dermatomyositis. She had been treated with MTX (12 mg/week) and prednisolone (5 mg/day) for dermatomyositis for 4 years. She developed painful stomatitis, fever, and pancytopenia. Initially, her symptoms were suspected to be caused by mucosal toxicity of MTX. Therefore, the drug was discontinued, and leucovorin was administered. However, oral stomatitis worsened in a few days, resulting in intolerance of oral ingestion due to severe pain. Polymerase chain reaction revealed the presence of herpes simplex virus type 1 (HSV-1) in oral erosive lesions, and blood examination was positive and negative for anti-HSV IgG and anti-HSV IgM, respectively. Therefore, HSV-1 reactivation-induced oral stomatitis was diagnosed, and acyclovir treatment was started, which promptly improved oral stomatitis. HSV-1 reactivation is usually asymptomatic or results in localized vesicular lesions at the mucocutaneous junction of the lips in immunocompetent individuals. Our case illustrates that HSV-1 reactivation induces severe stomatitis in patients treated with low-dose MTX for autoimmune diseases, not just in those with severe immunosuppressive conditions. Of note, HSV-1 reactivation-induced stomatitis is a diagnostic challenge, especially during MTX treatment.

Tsukamurella pulmonis central venous catheter infection mimicking proteinase 3-antineutrophil cytoplasmic antibody (PR3-ANCA)-associated vasculitis.

A 40-year-old Japanese woman, who underwent total thyroidectomy, had suffered from repeated episodes of fever and microscopic hematuria for 3 years, which had started 3 months after central venous port catheter insertion. On admission, she had malaise and low-grade fever, and was found to have microscopic hematuria, urinary red blood cell casts, multiple pulmonary nodules, and positivity of proteinase 3-anti-neutrophil cytoplasmic antibody (PR3-ANCA), which were suggestive to the presence of ANCA-associated small vessel vasculitis. However, her blood culture and subsequent gene analysis revealed the positivity of Tsukamurella pulmonis, and she was diagnosed with Tsukamurella pulmonis bacteremia accompanying PR3-ANCA positivity. Her condition improved after the removal of the catheter and antibiotic treatment. Tsukamurella species are categorized to the order Actinomycetales and can be misidentified as other Actinomycetales without genetic analyses. This case illustrates that chronic Tsukamurella pulmonis infection can cause ANCA production and nephritis, which mimics ANCA-associated vasculitis. Thus, it is critical to diagnose these cases correctly to avoid misdiagnosis and inappropriate treatment, such as immunosuppressive treatment.