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The translatability of research is highly dependent on models that recapitulate human tissues and organs. Here, we describe a procedure for the generation of human epidermis organotypic cultures (HEOCs) from primary keratinocytes isolated from foreskin and adult skin as well as from an immortalized keratinocyte cell line (KerTr). We tested several media conditions to develop a defined HEOC growing and expansion media. We characterized the HEOCs and show that in optimal culture conditions they express the proliferation marker Ki67, the basement membrane protein collagen 17 (col17) and the epidermal differentiation markers keratin 15 (K15), keratin 14 (K14), keratin 5 (K5), keratin 10 (K10), keratin 1 (K1), transglutaminase 1 (TGM1), transglutaminase 3 (TGM3) and filaggrin (FLG). Thus, they recapitulate the human epidermis and are stratified from the basal layer to the stratum corneum. These HEOC can be generated reproducibly on a large scale, making it an invaluable model for screening therapeutic compounds and also for the study of pathologies affecting the epidermis. [ABSTRACT FROM AUTHOR]

Background: Stevens–Johnson syndrome (SJS) and toxic epidermal necrolysis (TEN) are rare but potentially life‐threatening cutaneous adverse reactions. There is still no consensus on adjuvant treatments, and little is known about their effects on systemic inflammation in SJS/TEN. Our aim was to characterize the systemic and cutaneous immune profiles of SJS/TEN patients and to investigate whether/how intravenous immunoglobulins (IVIG), cyclosporine A (CSA), and best supportive care only (BSCO) affected the systemic immune signature and clinical outcome (6 week‐mortality, complications, hospitalization stay). Methods: We included 16 patients with SJS/TEN, treated with high‐dose IVIG (n = 8), CSA (n = 4) or BSCO (n = 4). Serial serum samples were obtained prior‐, 5–7 days, and 21 days after treatment onset. Serum levels of inflammation−/immune response‐associated proteins were measured by high‐throughput proteomics assay (OLINK) and cytotoxic molecules by ELISA. RNA extracted from skin biopsies collected prior treatment was analyzed by Nanostring. Results: Serum inflammatory profiles in SJS/TEN patients were notably characterized by massive upregulation of type 1 immune response and proinflammatory markers. Surprisingly, there was limited overlap between cutaneous and serum immune profiles. Serial serological measurements of immune response markers showed very diverse dynamics between the different treatment groups. IVIG‐treated patients showed completely different dynamics and most significant proteomic changes in an early phase (Day 5–7). In all treatment groups, type 1−/inflammatory response markers were dampened at day 21. Clinically, there were no outcome differences. Conclusion: Our study demonstrates that BSCO, CSA, and IVIG have very diverse biological effects on the systemic inflammatory response in SJS/TEN, which may not correlate with clinical outcome differences. [ABSTRACT FROM AUTHOR]

This article discusses a study on Stevens-Johnson syndrome (SJS) and toxic epidermal necrolysis (TEN), which are rare types of drug hypersensitivity reactions. The study aimed to compare the proteomic profiles of SJS/TEN patients receiving different adjuvant therapies in order to provide a basis for further investigations. The authors acknowledge the limitations of their study, including the small number of patients, differences in baseline characteristics, and the type of sampling used. They also mention the need for future studies to analyze both skin and blood samples. The article concludes by mentioning an ongoing clinical trial that may provide more information on adjuvant treatments for SJS/TEN. [Extracted from the article]

In Sézary syndrome (SS) impaired T-cell function and cytokine profile lead to immune evasion. Immune checkpoints non-redundantly regulate immune responses and targeting them is promising. We evaluated the expression of BTLA, CTLA-4, FCRL3, LAG-3, and TIGIT in tumor and non-tumor SS T-cells.Compared to CD4+ T helper cells from ten healthy individuals, tumor cells of eight SS patients had a significant upregulation of BTLA (1.5-fold; p <.0001), FRCL3 (2.2-fold; p <.0028) and TIGIT (2.2-fold; p <.0003) expression. In contrast, we found a reduced expression of LAG-3+ cells in the blood of tumor patients (0.5-fold; p <.0014). Only weak alternations between tumor, non-tumor cells, and healthy controls were observed regarding CTLA-4 (0.5-fold; p <.2022). Our results show a diverse expression pattern of immune-regulatory molecules in SS patients. As these molecules are essential in the regulation of T-cell mediated tumor surveillance and defense, their specific targeting might be of clinical relevance. [ABSTRACT FROM AUTHOR]

In 2002, intracellular protein complexes known as the inflammasomes were discovered and were shown to have a crucial role in the sensing of intracellular pathogen- and danger-associated molecular patterns (PAMPs and DAMPs). Activation of the inflammasomes results in the processing and subsequent secretion of the pro-inflammatory cytokines IL-1β and IL-18. Several autoinflammatory disorders such as cryopyrin-associated periodic syndromes and Familial Mediterranean Fever have been associated with mutations of genes encoding inflammasome components. Moreover, the importance of IL-1 has been reported for an increasing number of autoinflammatory skin diseases including but not limited to deficiency of IL-1 receptor antagonist, mevalonate kinase deficiency and PAPA syndrome. Recent findings have revealed that excessive IL-1 release induced by harmful stimuli likely contributes to the pathogenesis of common dermatological diseases such as acne vulgaris or seborrheic dermatitis. A key pathogenic feature of these diseases is IL-1β-induced neutrophil recruitment to the skin. IL-1β blockade may therefore represent a promising therapeutic approach. Several case reports and clinical trials have demonstrated the efficacy of IL-1 inhibition in the treatment of these skin disorders. Next to the recombinant IL-1 receptor antagonist (IL-1Ra) Anakinra and the soluble decoy Rilonacept, the anti-IL-1α monoclonal antibody MABp1 and anti-IL-1β Canakinumab but also Gevokizumab, LY2189102 and P2D7KK, offer valid alternatives to target IL-1. Although less thoroughly investigated, an involvement of IL-18 in the development of cutaneous inflammatory disorders is also suspected. The present review describes the role of IL-1 in diseases with skin involvement and gives an overview of the relevant studies discussing the therapeutic potential of modulating the secretion and activity of IL-1 and IL-18 in such diseases. [ABSTRACT FROM AUTHOR]

Sézary syndrome is a primary cutaneous T-cell lymphoma characterized by pruritic erythroderma, peripheral lymphadenopathy and the presence of malignant T cells in the blood. Unequivocal detection of malignant cells in patients with Sézary syndrome is of important diagnostic, prognostic and therapeutic value. However, no single Sézary syndrome specific cell surface marker has been identified. In a cohort of patients with Sézary syndrome, CD164 expression on total CD4+ lymphocytes was significantly upregulated compared with healthy controls. CD164 expression was in most cases limited to CD4+CD26- malignant T lymphocytes, unequivocally identified using flow-cytometry by the expression of a specific Vβ clone for each patient. Increased expression of CD164 may be a promising diagnostic parameter and a potential target for a CD164-linked therapeutic approach in Sézary syndrome. [ABSTRACT FROM AUTHOR]

Sweet's syndrome (SS) is a dermatosis with systemic symptoms characterized by tender, red nodules or papules, occasionally covered with vesicles, pustules or bullae, usually affecting the upper limbs, face and neck. SS is frequently observed in patients with leukemia or connective tissue diseases, while it is rather seldom in patients with inflammatory bowel disease. The exact pathogenesis of SS is only partially understood. We report the case of a 50-year-old patient with indeterminate colitis, presenting with a febrile diffuse papulopustular and necrotizing skin eruption that healed with significant scarring and appeared 14 days after onset of treatment with azathioprine. Histological examination revealed the presence of features typical of SS, gene expression analysis very high levels of interleukin-1β (IL-1β) mRNA in lesional skin, and immunohistochemistry high levels of IL-1β at the protein level. SS associated with azathioprine is being increasingly reported and is reviewed herein. [ABSTRACT FROM AUTHOR]

Sweet's syndrome (SS) is a dermatosis with systemic symptoms characterized by tender, red nodules or papules, occasionally covered with vesicles, pustules or bullae, usually affecting the upper limbs, face and neck. SS is frequently observed in patients with leukemia or connective tissue diseases, while it is rather seldom in patients with inflammatory bowel disease. The exact pathogenesis of SS is only partially understood. We report the case of a 50-year-old patient with indeterminate colitis, presenting with a febrile diffuse papulopustular and necrotizing skin eruption that healed with significant scarring and appeared 14 days after onset of treatment with azathioprine. Histological examination revealed the presence of features typical of SS, gene expression analysis very high levels of interleukin-1β (IL-1β) mRNA in lesional skin, and immunohistochemistry high levels of IL-1β at the protein level. SS associated with azathioprine is being increasingly reported and is reviewed herein. © 2015 S. Karger AG, Basel [ABSTRACT FROM AUTHOR]

Although being a normal part of the skin flora, yeasts of the genus Malassezia are associated with several common dermatologic conditions including pityriasis versicolour, seborrhoeic dermatitis ( SD), folliculitis, atopic eczema/dermatitis ( AE/ AD) and dandruff. While Malassezia spp. are aetiological agents of pityriasis versicolour, a causal role of Malassezia spp. in AE/ AD and SD remains to be established. Previous reports have shown that fungi such as Candida albicans and Aspergillus fumigatus are able to efficiently activate the NLRP3 inflammasome leading to robust secretion of the pro-inflammatory cytokine IL-1 β. To date, innate immune responses to Malassezia spp. are not well characterized. Here, we show that different Malassezia species could induce NLRP3 inflammasome activation and subsequent IL-1 β secretion in human antigen-presenting cells. In contrast, keratinocytes were not able to secrete IL-1 β when exposed to Malassezia spp. Moreover, we demonstrate that IL-1 β secretion in antigen-presenting cells was dependent on Syk-kinase signalling. Our results identify Malassezia spp. as potential strong inducers of pro-inflammatory responses when taken up by antigen-presenting cells and identify C-type lectin receptors and the NLRP3 inflammasome as crucial actors in this process. [ABSTRACT FROM AUTHOR]

Summary The incidence of melanoma has significantly increased, and a better understanding of its pathogenesis and development of new therapeutic strategies are urgently needed. Here, we describe a murine model of metastatic cutaneous melanoma using C57BL/6 mice expressing a mutated human N-Ras gene under the control of a tyrosinase promoter (TyrRas). These mice were topically exposed to 7,12- dimethylbenzanthracene (DMBA) for brief exposure periods. Cutaneous melanoma developed at the site of exposure on average by 19 weeks of age and in 80% of mice. Importantly, as in humans, melanoma development was associated with subsequent metastasis to tumor-draining lymph nodes. Critically, such metastatic behavior is transplantable, as intradermal inoculation of melanoma cells from TyrRas-DMBA mice into non-transgenic mice led to the growth of melanoma and, again, metastasis to skin-draining lymph nodes. This metastatic melanoma model closely mimics human pathology and should be a useful tool for studying melanoma pathogenesis and developing new therapies. [ABSTRACT FROM AUTHOR]

Interleukin-11α (IL-11α) and -β both bind to the same IL-1 receptor (IL-1R) and are potent proinflammatory cytokines. Production of proinflammatory (pro)-IL-11α and pro-IL-1β is induced by Toll-like receptor (TLR)-mediated NF-κ activation. Additional stimulus involving activation of the inflammasome and caspase-1 is required for proteolytic cleavage and secretion of mature IL-1β. The regulation of IL-11α maturation and secretion, however, remains elusive. IL-11α exists as a cell surface-associated form and as a mature secreted form. Here we show that both forms of IL-11α, the surface and secreted form, are differentially regulated. Surface IL-11α requires NF-κ activation only, whereas secretion of mature IL-11α requires additional activation of the inflammasome and caspase-1. Surprisingly, secretion of IL-11α also required the presence of IL-1β, as demonstrated in IL-1β-deficient mice. We further demonstrate that IL-1β directly binds IL-11α, thus identifying IL-1β as a shuttle for another proinflammatory cytokine. These results have direct impact on selective treatment modalities of inflammatory diseases. [ABSTRACT FROM AUTHOR]

Apremilast (Otezla®) is an oral small molecule phosphodiesterase 4 (PDE4) inhibitor approved for the treatment of psoriasis, psoriatic arthritis, and oral ulcers associated with Behçet's disease. While PDE4 inhibition overall is mechanistically understood, the effect of apremilast on the innate immune response, particularly inflammasome activation, remains unknown. Here, we assessed the effect of apremilast in a psoriasis mouse model and primary human cells. Psoriatic lesion development in vivo was studied in K5.Stat3C transgenic mice treated with apremilast for 2 weeks, resulting in a moderate (2 mg/kg/day) to significant (6 mg/kg/day) resolution of inflamed plaques after 2-week treatment. Concomitantly, epidermal thickness dramatically decreased, the cutaneous immune cell infiltrate was reduced, and proinflammatory cytokines were significantly downregulated. Additionally, apremilast significantly inhibited lipopolysaccharide- or anti-CD3-induced expression of proinflammatory cytokines in peripheral mononuclear cells (PBMCs). Notably, inflammasome activation and secretion of IL-1β were not inhibited by apremilast in PBMCs and in human primary keratinocytes. Collectively, apremilast effectively alleviated the psoriatic phenotype of K5.Stat3 transgenic mice, further substantiating PDE4 inhibitor-efficiency in targeting key clinical, histopathological and inflammatory features of psoriasis. Despite lacking direct effect on inflammasome activation, reduced priming of inflammasome components upon apremilast treatment reflected the indirect benefit of PDE4 inhibition in reducing inflammation. [ABSTRACT FROM AUTHOR]

T cell tolerance to self-antigens is believed to be achieved in a two-step process. The first step, called central tolerance, takes place in the thymus. The second step takes place outside the thymus in secondary lymphoid organs. One may ask why two mechanisms are needed to insure T cell tolerance. These two mechanisms share redundant functions and dysfunctions, leading to T cell-mediated autoimmune syndromes. By reviewing the literature on relevant animal models for T cell tolerance and our own recent findings, we are providing evidences that only central tolerance is acting for the skin. [ABSTRACT FROM AUTHOR]