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"This is the pre-peer reviewed version of the following article, which has been published in final form at [https://doi.dx.org/10.1111/j.1600-0846.2010.00461.x]. This article may be used for non-commercial purposes in accordance with Wiley Terms and Conditions for Self-Archiving", Background Filaggrin (FLG) gene mutations, which result in complete or incomplete loss of proFLG/FLG peptides, have been reported as an important predisposing factor for atopic dermatitis (AD) and secondary atopic phenotypes such as atopic asthma. Method The presence of the protein FLG in the skin was evaluated at birth on 12 infants using Raman spectroscopy; these 12 infants were monitored for 1 year to see whether they developed AD. Three different statistical analysis procedures, two of which involved principal component analysis (PCA), were performed on the Raman spectra in order to determine the FLG content. Results The infants who had a lower FLG content, determined using any of the three statistical analysis procedures proposed, were also the ones that clinically developed AD. Conclusion The results suggest that Raman spectroscopy and statistical analysis such as PCA could be used as an early detection procedure for FLG -related AD and as a possible quantitative marker for FLG gene mutations, Consejo Nacional de Ciencia y Tecnología (CONACyT), Fondos Mixtos San Juan Potosí (FOMIX-SLP), Ministerio de Educación y Ciencia de España, Unidad Docente de Biodiversidad, Ecología y Evolución, Fac. de Óptica y Optometría, TRUE, pub

Background There is currently no insight into biomarkers that can predict the onset of pediatric atopic dermatitis (AD). Methods Nested in a prospective birth cohort study that examined the occurrence of physician-diagnosed AD in 300 children, 44 random children with onset of AD in the first year of life were matched on sex and season of birth with 44 children who did not develop AD. Natural moisturizing factor (NMF), corneocyte surface protrusions, cytokines, free sphingoid bases (SBs) of different chain lengths and their ceramides were analyzed from tape strips collected at 2 months of age before onset of AD using liquid chromatography, atomic force microscopy, multiplex immunoassay, and liquid chromatography mass spectrometry, respectively. Results Significant alterations were observed for four lipid markers, with phytosphingosine ([P]) levels being significantly lower in children who developed AD compared with children who did not (median 240 pmol/mg vs. 540 pmol/mg, p < 0.001). The two groups of children differed in the relative amounts of SB of different chain lengths (C17, C18 and C20). Thymus- and activation-regulated chemokine (TARC/CCL17) was slightly higher in children who developed AD, whereas NMF and corneocyte surface texture were similar. AD severity assessed by the eczema area and severity index (EASI) at disease onset was 4.2 (2.0;7.2). [P] had the highest prediction accuracy among the biomarkers (75.6%), whereas the combination of 5 lipid ratios gave an accuracy of 89.4%. Conclusion This study showed that levels and SB chain length were altered in infants who later developed AD, and that TARC/CCL17 levels were higher.

Background There is currently no insight into biomarkers that can predict the onset of pediatric atopic dermatitis (AD). Methods Nested in a prospective birth cohort study that examined the occurrence of physician-diagnosed AD in 300 children, 44 random children with onset of AD in the first year of life were matched on sex and season of birth with 44 children who did not develop AD. Natural moisturizing factor (NMF), corneocyte surface protrusions, cytokines, free sphingoid bases (SBs) of different chain lengths and their ceramides were analyzed from tape strips collected at 2 months of age before onset of AD using liquid chromatography, atomic force microscopy, multiplex immunoassay, and liquid chromatography mass spectrometry, respectively. Results Significant alterations were observed for four lipid markers, with phytosphingosine ([P]) levels being significantly lower in children who developed AD compared with children who did not (median 240 pmol/mg vs. 540 pmol/mg, p < 0.001). The two groups of children differed in the relative amounts of SB of different chain lengths (C17, C18 and C20). Thymus- and activation-regulated chemokine (TARC/CCL17) was slightly higher in children who developed AD, whereas NMF and corneocyte surface texture were similar. AD severity assessed by the eczema area and severity index (EASI) at disease onset was 4.2 (2.0;7.2). [P] had the highest prediction accuracy among the biomarkers (75.6%), whereas the combination of 5 lipid ratios gave an accuracy of 89.4%. Conclusion This study showed that levels and SB chain length were altered in infants who later developed AD, and that TARC/CCL17 levels were higher.

Filaggrin mutations underlie ichthyosis vulgaris and increased risk of atopic dermatitis, conditions typified by disruption of the skin microbiome and cutaneous immune response. Yet, it remains unclear if neonatal skin barrier compromise due to filaggrin deficiency alters the quality of commensal-specific T cells and the functional impact of such responses. To address these questions, we profiled changes in the skin barrier and early cutaneous immune response of neonatal C57BL/6 Flg-/- and WT mice using scRNAseq, flow cytometry and other modalities. Flg-/- neonates showed little alteration in transepidermal water loss or lipid or corneocyte related gene expression. However, they demonstrated increases in barrier disruption genes, epidermal dye penetration and numbers of skin CD4+ T cells. Using an engineered strain of Staphylococcus epidermidis (S. epi-2W) to study the response to neonatal skin colonization, we found that commensal-specific CD4+ T cells were skewed in Flg-/- pups towards effector rather than regulatory T cells. This altered response persisted into adulthood, where it was typified by Th17 cells and associated with increased susceptibility to imiquimod-induced skin inflammation. Thus, subtle but impactful differences in neonatal barrier function in Flg-/- mice are accompanied by a skewed commensal-specific CD4+ response, with enduring consequences for skin immune homeostasis.

BackgroundWhile numerous genetic loci associated with atopic dermatitis (AD) have been discovered, to date, work leveraging the combined burden of AD risk variants across the genome to predict disease risk has been limited.ObjectivesThis study aims to determine whether polygenic risk scores (PRSs) relying on genetic determinants for AD provide useful predictions for disease occurrence and severity. It also explicitly tests the value of including genome-wide association studies of related allergic phenotypes and known FLG loss-of-function (LOF) variants.MethodsAD PRSs were constructed for 1619 European American individuals from the Atopic Dermatitis Research Network using an AD training dataset and an atopic training dataset including AD, childhood onset asthma, and general allergy. Additionally, whole genome sequencing data were used to explore genetic scoring specific to FLG LOF mutations.ResultsGenetic scores derived from the AD-only genome-wide association studies were predictive of AD cases (PRSAD: odds ratio [OR], 1.70; 95% CI, 1.49-1.93). Accuracy was first improved when PRSs were built off the larger atopy genome-wide association studies (PRSAD+: OR, 2.16; 95% CI, 1.89-2.47) and further improved when including FLG LOF mutations (PRSAD++: OR, 3.23; 95% CI, 2.57-4.07). Importantly, while all 3 PRSs correlated with AD severity, the best prediction was from PRSAD++, which distinguished individuals with severe AD from control subjects with OR of 3.86 (95% CI, 2.77-5.36).ConclusionsThis study demonstrates how PRSs for AD that include genetic determinants across atopic phenotypes and FLG LOF variants may be a promising tool for identifying individuals at high risk for developing disease and specifically severe disease.

Although lipids are crucial molecules for cell structure, metabolism, and signaling in most organs, they have additional specific functions in the skin. Lipids are required for the maintenance and regulation of the epidermal barrier, physical properties of the skin, and defense against microbes. Analysis of the lipidomeethe totality of lipidseis of similar complexity to those of proteomics or other omics, with lipid structures ranging from simple, linear, to highly complex structures. In addition, the ordering and chemical modifications of lipids have consequences on their biological function, especially in the skin. Recent advances in analytic capability (usually with mass spectrometry), bioinformatic processing, and integration with other dermatological big data have allowed researchers to increasingly understand the roles of specific lipid species in skin biology. In this paper, we review the techniques used to analyze skin lipidomics and epilipidomics.

Objectives: The skin is the largest sensory organ of the human body and plays a fundamental role in regulating body temperature. However, adaptive alterations in skin functions and morphology have only vaguely been associated with physiological responses to cold stress or sensation of ambient temperatures. We previously found that loss of acyl-CoA-binding protein (ACBP) in keratinocytes upregulates lipolysis in white adipose tissue and alters hepatic lipid metabolism, suggesting a link between epidermal barrier functions and systemic energy metabolism. Methods: To assess the physiological responses to loss of ACBP in keratinocytes in detail, we used full-body ACBP−/− and skin-specific ACBP−/− knockout mice to clarify how loss of ACBP affects 1) energy expenditure by indirect calorimetry, 2) response to high-fat feeding and a high oral glucose load, and 3) expression of brown-selective gene programs by quantitative PCR in inguinal WAT (iWAT). To further elucidate the role of the epidermal barrier in systemic energy metabolism, we included mice with defects in skin structural proteins (ma/ma Flgft/ft) in these studies. Results: We show that the ACBP−/− mice and skin-specific ACBP−/− knockout mice exhibited increased energy expenditure, increased food intake, browning of the iWAT, and resistance to diet-induced obesity. The metabolic phenotype, including browning of the iWAT, was reversed by housing the mice at thermoneutrality (30 °C) or pharmacological β-adrenergic blocking. Interestingly, these findings were phenocopied in flaky tail mice (ma/ma Flgft/ft). Taken together, we demonstrate that a compromised epidermal barrier induces a β-adrenergic response that increases energy expenditure and browning of the white adipose tissue to maintain a normal body temperature. Conclusions: Our findings show that the epidermal barrier plays a key role in maintaining systemic metabolic homeostasis. Thus, regula

Atopic dermatitis is a common inflammatory skin disease with a complex pathogenesis that includes imbalanced immune system signalling, impaired skin barrier and enhanced Staphylococcus aureus skin colonization. The skin bacterial communities are characterized by increasing abundance of S. aureus, leading to reduced diversity compared with the bacterial communities on healthy skin, and increasing disease severity. In contrast, fungal communities are richer and more diverse on the skin of patients with atopic dermatitis, although distribution of the most common species is similar in patients and controls. Filaggrin deficiency in atopic dermatitis skin might be related to the enhanced skin colonization by S. aureus. In addition, S. aureus expressing variant virulence factors have been shown to elicit atopic dermatitis-like phenotypes in mice, indicating that specific S. aureus strains can induce flare-ups. This review aims to provide an overview of the recent literature on the skin microbiome in atopic dermatitis.

Atopic dermatitis is a common inflammatory skin disease with a complex pathogenesis that includes imbalanced immune system signalling, impaired skin barrier and enhanced Staphylococcus aureus skin colonization. The skin bacterial communities are characterized by increasing abundance of S. aureus, leading to reduced diversity compared with the bacterial communities on healthy skin, and increasing disease severity. In contrast, fungal communities are richer and more diverse on the skin of patients with atopic dermatitis, although distribution of the most common species is similar in patients and controls. Filaggrin deficiency in atopic dermatitis skin might be related to the enhanced skin colonization by S. aureus. In addition, S. aureus expressing variant virulence factors have been shown to elicit atopic dermatitis-like phenotypes in mice, indicating that specific S. aureus strains can induce flare-ups. This review aims to provide an overview of the recent literature on the skin microbiome in atopic dermatitis.

Background: Nevus is a hamartoma or malformation of one or more skin components, resulting in aberrant differentiation of the cell lineage(s) mostly during developmental stages. Although multiple lineages may be involved in a nevus, the combination of melanocyte and keratinocyte abnormalities has been rarely discussed. Objectives. To present two cases of congenital nevi with hypomelanosis and superficial fine scales. Materials & Methods: Skin specimens of the patients were analysed by immunohistochemistry and electron microscopy. Results: Morphological and immunohistochemical studies indicated aberrant epidermal differentiation in the lesional skin specimens. Electron microscopy showed defective melanosome maturation in the melanocytes of the nevi samples. Conclusion: These results demonstrate that both epidermal and melanocytic lineages can concomitantly contribute to the formation of a nevus lesion.

Background: Nevus is a hamartoma or malformation of one or more skin components, resulting in aberrant differentiation of the cell lineage(s) mostly during developmental stages. Although multiple lineages may be involved in a nevus, the combination of melanocyte and keratinocyte abnormalities has been rarely discussed. Objectives. To present two cases of congenital nevi with hypomelanosis and superficial fine scales. Materials & Methods: Skin specimens of the patients were analysed by immunohistochemistry and electron microscopy. Results: Morphological and immunohistochemical studies indicated aberrant epidermal differentiation in the lesional skin specimens. Electron microscopy showed defective melanosome maturation in the melanocytes of the nevi samples. Conclusion: These results demonstrate that both epidermal and melanocytic lineages can concomitantly contribute to the formation of a nevus lesion.

Background: Nevus is a hamartoma or malformation of one or more skin components, resulting in aberrant differentiation of the cell lineage(s) mostly during developmental stages. Although multiple lineages may be involved in a nevus, the combination of melanocyte and keratinocyte abnormalities has been rarely discussed. Objectives. To present two cases of congenital nevi with hypomelanosis and superficial fine scales. Materials & Methods: Skin specimens of the patients were analysed by immunohistochemistry and electron microscopy. Results: Morphological and immunohistochemical studies indicated aberrant epidermal differentiation in the lesional skin specimens. Electron microscopy showed defective melanosome maturation in the melanocytes of the nevi samples. Conclusion: These results demonstrate that both epidermal and melanocytic lineages can concomitantly contribute to the formation of a nevus lesion.

Background: Nevus is a hamartoma or malformation of one or more skin components, resulting in aberrant differentiation of the cell lineage(s) mostly during developmental stages. Although multiple lineages may be involved in a nevus, the combination of melanocyte and keratinocyte abnormalities has been rarely discussed. Objectives. To present two cases of congenital nevi with hypomelanosis and superficial fine scales. Materials & Methods: Skin specimens of the patients were analysed by immunohistochemistry and electron microscopy. Results: Morphological and immunohistochemical studies indicated aberrant epidermal differentiation in the lesional skin specimens. Electron microscopy showed defective melanosome maturation in the melanocytes of the nevi samples. Conclusion: These results demonstrate that both epidermal and melanocytic lineages can concomitantly contribute to the formation of a nevus lesion.

Background: Initially after tattooing, the skin barrier function is broken. However, the long-term impact of clinically healed tattoos on this has never been studied. The aim was to investigate the long-term effect on the skin barrier function in normal tattoos and examples of tattoos with chronic inflammatory complication. Methods: Participants were recruited from the “Tattoo clinic” of the Dermatological Department on Bispebjerg Hospital in Denmark, where patients with complicated tattoo reactions are treated. Transepidermal water loss (TEWL), conductance, capacitance, and pH were measured in tattooed skin with regional control measurements in normal non-tattooed skin. Natural moisturizing factor (NMF) was measured in collected tape strips. Results: Twenty six individuals with 28 tattoos were included, that is, 23 normal tattoos without any pathologic reaction and 5 tattoos with chronic inflammatory complications. No significant differences were found in tattooed versus non-tattooed skin with respect to TEWL (median values 6.6 vs 7.2 g/m 2 /h), conductance (76 vs 78 a.u.), pH (5.94 vs 5.79), and NMF (0.58 vs 0.59 mmol/g protein). Capacitance (64 vs 57 a.u.) was higher in tattooed skin compared to non-tattooed skin (P = 0.006). Similar results were found in tattoos with inflammatory reactions. Conclusion: Overall, skin tattoos do not affect the long-term skin barrier function markedly. The skin capacitance was, however, affected in tattooed skin areas compared to non-tattooed skin areas.

This study investigated serum 25-hydroxyvitamin D (25(OH)D) concentrations and circulating regulatory T cells in patients with atopic dermatitis receiving narrow-band ultraviolet B (nbUVB) phototherapy. Thirty adult patients with atopic dermatitis were included. Blood samples were collected at baseline and at weeks 2 and 4 of nbUVB phototherapy. Skin biopsies were taken at baseline and at week 4. Serum 25(OH) D concentrations increased significantly following nbUVB phototherapy (estimate of change from baseline to week 2: 32.00 nmol/l, confidence interval (CI) 20.48–43.52, p < 0.0001, n = 25; and from baseline to week 4: 50.30 nmol/l, CI 37.28–63.33, p < 0.0001, n = 18). This increase was independent of the filaggrin gene loss-of-function mutation status. Flow cytometry showed no significant change in regulatory T cells or cytokine profiles of T cells in blood. Real-time quantitative PCR showed no change in skin cytokine levels. In conclusion, nbUVB phototherapy was associated with increased serum 25(OH)D concentrations, but not changes in circulating regulatory T cells in patients with atopic dermatitis.

This study investigated serum 25-hydroxyvitamin D (25(OH)D) concentrations and circulating regulatory T cells in patients with atopic dermatitis receiving narrow-band ultraviolet B (nbUVB) phototherapy. Thirty adult patients with atopic dermatitis were included. Blood samples were collected at baseline and at weeks 2 and 4 of nbUVB phototherapy. Skin biopsies were taken at baseline and at week 4. Serum 25(OH) D concentrations increased significantly following nbUVB phototherapy (estimate of change from baseline to week 2: 32.00 nmol/l, confidence interval (CI) 20.48–43.52, p < 0.0001, n = 25; and from baseline to week 4: 50.30 nmol/l, CI 37.28–63.33, p < 0.0001, n = 18). This increase was independent of the filaggrin gene loss-of-function mutation status. Flow cytometry showed no significant change in regulatory T cells or cytokine profiles of T cells in blood. Real-time quantitative PCR showed no change in skin cytokine levels. In conclusion, nbUVB phototherapy was associated with increased serum 25(OH)D concentrations, but not changes in circulating regulatory T cells in patients with atopic dermatitis.

The tissue engineering self-assembly approach allows the production of skin substitutes comprising both the dermis and epidermis, using methods promoting the secretion and organization of a dense extracellular matrix by skin cells. In a reconstructed epidermis, all cellular layers of the native tissue are present. An evaluation of the expression and localization of a number of specific protein markers revealed that the self-assembled, tissue-engineered skin substitute shares some common features with normal human skin, such as the expression of Ki-67, keratins 10 and 14, filaggrin, involucrin, transglutaminase, DLK, a3-integrin subunit, laminin-S, and collagens I, II, 1V, and VII. At the ultrastructural level, many differentiation markers can be observed, including desmosomes, as well as an organized basement membrane presenting hemidesmosomes, lamina densa, and lamina lucida. In this chapter, protocols to generate skin substitutes by the self-assembly approach will be presented and the methods including the labeling of the principal skin differentiation markers by immunofluorescence will be examined.

The tissue engineering self-assembly approach allows the production of skin substitutes comprising both the dermis and epidermis, using methods promoting the secretion and organization of a dense extracellular matrix by skin cells. In a reconstructed epidermis, all cellular layers of the native tissue are present. An evaluation of the expression and localization of a number of specific protein markers revealed that the self-assembled, tissue-engineered skin substitute shares some common features with normal human skin, such as the expression of Ki-67, keratins 10 and 14, filaggrin, involucrin, transglutaminase, DLK, a3-integrin subunit, laminin-S, and collagens I, II, 1V, and VII. At the ultrastructural level, many differentiation markers can be observed, including desmosomes, as well as an organized basement membrane presenting hemidesmosomes, lamina densa, and lamina lucida. In this chapter, protocols to generate skin substitutes by the self-assembly approach will be presented and the methods including the labeling of the principal skin differentiation markers by immunofluorescence will be examined., 0

Canine atopic dermatitis (CAD) is an immune-mediated disease characterized by inflammatory and pruritic processes. Recent theories propose that epidermal barrier failures can facilitate the entry of potential allergens, microorganisms and irritants, increasing the interaction with cells of the immune system, causing its excessive stimulation. Therefore, the present review aims to describe the main epidermal changes that contribute to the pathogenesis of CAD, as well as to present therapies used to recover the skin barrier. The most frequent changes in the epidermis of atopic animals involve transepidermal water loss, lipid and protein dysfunctions. Ceramides are lipids with structural functions, but they are also involved in cell signaling. These molecules, although present, have reduced concentrations in the skin of dogs with CAD, which is considered both primary and secondary defects of inflammatory processes. Other epidermal components, such as filaggrin, an essential protein in development and maintenance of skin barrier integrity, and antimicrobial peptides responsible for defense against pathogens and modulation of immune response, have mutations in atopic animals, contributing to the appearance of recurrent infections. These defects in cutaneous barrier may contribute to the pathogenesis of CAD, and such information helps in the treatment of this pathology, improving animal welfare with skin-healing therapies.

The tissue engineering self-assembly approach allows the production of skin substitutes comprising both the dermis and epidermis, using methods promoting the secretion and organization of a dense extracellular matrix by skin cells. In a reconstructed epidermis, all cellular layers of the native tissue are present. An evaluation of the expression and localization of a number of specific protein markers revealed that the self-assembled, tissue-engineered skin substitute shares some common features with normal human skin, such as the expression of Ki-67, keratins 10 and 14, filaggrin, involucrin, transglutaminase, DLK, a3-integrin subunit, laminin-S, and collagens I, II, 1V, and VII. At the ultrastructural level, many differentiation markers can be observed, including desmosomes, as well as an organized basement membrane presenting hemidesmosomes, lamina densa, and lamina lucida. In this chapter, protocols to generate skin substitutes by the self-assembly approach will be presented and the methods including the labeling of the principal skin differentiation markers by immunofluorescence will be examined., 0

Background and Aim: Exposure to phthalates and phosphorus flame retardants (PFRs) is considered to be a risk factor for asthma and allergies. However, little is known about the contribution of loss-of-function mutations in the gene encoding filaggrin (FLG) gene, which are considered to be predisposing factors for eczema and asthma, to these associations. We investigated the associations between exposure to phthalates and PFRs in dust and eczema/wheeze among Japanese children, taking into consideration loss-of-function mutations in FLG. Methods: This study was part of the Hokkaido study on Environment and Children's Health. Seven phthalates and 11 PFRs in household dust were measured by gas chromatography-mass spectrometry. Eczema and wheeze were assessed in children aged 7 years using the International Study of Asthma and Allergies in Childhood questionnaire. Eight FLG mutations previously identified in the Japanese population were extracted from cord blood samples. Children with one or more FLG mutations were considered to be positive for FLG mutations. The study included 296 children who had complete data (birth records, FLG mutations, first trimester and 7 years questionnaires, and phthalate/PFR levels). Odds ratios (ORs) and 95% confidential intervals (CIs) of eczema and wheeze were calculated for log-transformed phthalate/PFR levels by logistic regression. We also performed stratified analyses based on FLG mutations. Results: The prevalence rates of eczema and wheeze were 20.6% and 13.9%, respectively. Among children without any FLG mutations, tris (1, 3-dichloro-2-propyl) phosphate (TDCIPP) increased the OR of wheeze, (OR: 1.22, CI: 1.00-1.48). Significant p values for trends were found between tris (2-butoxyethyl) phosphate (TBOEP) and eczema and di-iso-nonyl phthalate (DiNP) and eczema among children without any FLG mutations, respectively. Conclusions: Despite our limited sample size and cross-sectional study design, the effects of indoor environmental fact

Canine atopic dermatitis (CAD) is an immune-mediated disease characterized by inflammatory and pruritic processes. Recent theories propose that epidermal barrier failures can facilitate the entry of potential allergens, microorganisms and irritants, increasing the interaction with cells of the immune system, causing its excessive stimulation. Therefore, the present review aims to describe the main epidermal changes that contribute to the pathogenesis of CAD, as well as to present therapies used to recover the skin barrier. The most frequent changes in the epidermis of atopic animals involve transepidermal water loss, lipid and protein dysfunctions. Ceramides are lipids with structural functions, but they are also involved in cell signaling. These molecules, although present, have reduced concentrations in the skin of dogs with CAD, which is considered both primary and secondary defects of inflammatory processes. Other epidermal components, such as filaggrin, an essential protein in development and maintenance of skin barrier integrity, and antimicrobial peptides responsible for defense against pathogens and modulation of immune response, have mutations in atopic animals, contributing to the appearance of recurrent infections. These defects in cutaneous barrier may contribute to the pathogenesis of CAD, and such information helps in the treatment of this pathology, improving animal welfare with skin-healing therapies.

Jüngste Forschungsergebnisse unterstreichen den Stellenwert von Lipiden in der Ausbildung der Hautbarriere, welche zum überwiegenden Teil im stratum corneum (SC) der Epidermis lokalisiert ist. Im Gegensatz dazu wurde die Rolle von Lipiden als Signalmoleküle in der Epidermis bis jetzt nicht eingehend untersucht. Ebenso sind die Mechanismen, welche die Expression von Liposensorproteinen - wie z. Bsp. den Peroxisom-Proliferator aktivierten Rezeptoren (PPAR) regulieren, wenig verstanden. Daher war das Ziel dieser Arbeit (i) die Rolle von mehrfach ungesättigten Fettsäuren (PUFA) - insbesondere den Eicosanoiden und ihren Vorläuferprodukten - und ihre Funktion als bioaktive Lipidmediatoren in der Ichthyosis Vulgaris (IV) sowie der Atopischen Dermatitis (AD) mit und ohne Filaggrin (FLG) Mutation zu untersuchen und (ii) die Mechanismen welche die PPAR Expression in Zuständen der akuten Barrierebeeinträchtigung regulieren näher zu entschlüsseln. Im ersten Teil dieser Arbeit verwendeten wir Keratinozyten von Patienten mit AD ohne FLG Mutation [AD (WT/WT)], mit AD mit FLG Mutation [AD (FLG/WT)], mit IV [IV (FLG/FLG)] und von FLG Wildtyp (WT) Kontrollpersonen um humane epidermale Hautäquivalente (HEE) zu generieren. Diese HEEs wurden verwendet um die mögliche autokrine/parakrine Rolle von epidermalen Eicosanoide in FLG-assoziierter vs. FLG-WT AD Pathogenese zu evaluieren. Elektronenmikroskopische Analysen zeigten abnormale SC Lipid Architektur in AD und IV HEEs, unabhängig vom FLG Genotyp. Sowohl AD (FLG/WT) wie auch IV (FLG/FLG) HEEs zeigten beeinträchtigte späte epidermale Differenzierung. Nur AD (FLG/WT) HEEs zeigten signifikant erhöhte Konzentrationen von inflammatorischen Zytokinen. Analysen von Lipid Mediatoren ergaben erhöhte Konzentrationen von Arachidonsäure (AA) und 12-LOX Metaboliten. Während die Behandlung von Kontroll-HEEs mit AA die Expression von inflammatorischen Zytokinen erhöhte, reduzierte 12-HETE die Expression von späten Differenzierungsmarkern. So führen FL, Recent research has attracted appreciable attention to the role of structural lipids in the formation of the permeability barrier that for a large part resides in the stratum corneum (SC). Yet, the role of lipids as signaling molecules in the epidermis remains elusive. Likewise, mechanisms regulating the expression of liposensors i.e. peroxisome-proliferator activated receptors (PPARs) have not yet been fully elucidated. Thus this work was aimed (i) at studying the role of poly unsaturated fatty acids (PUFAs) particularly of eicosanoids and their precursor products as bioactive lipid mediators in ichthyosis vulgaris (IV) and atopic dermatitis (AD) with and without filaggrin (FLG) mutations and (ii) at unraveling mechanisms involved in the regulation of PPAR expression in conditions of acute barrier impairment. In the first part of this thesis, we used epidermal equivalents (HEEs) generated with keratinocytes isolated from non-lesional skin of patients with FLG wild type AD (WT/WT), FLG-mutated AD (FLG/WT), IV (FLG/FLG) or FLG WT control skin to assess the potential autocrine/paracrine role of epidermal-derived eicosanoids in FLG-associated vs. FLG-WT AD pathogenesis. Ultrastructural analyses demonstrated abnormal SC lipid architecture in AD and IV HEEs, independent of FLG genotype. Both AD (FLG/WT) and IV (FLG/FLG) HEEs showed impaired late epidermal differentiation. Only AD (FLG/WT) HEEs exhibited significantly increased levels of inflammatory cytokines. Analyses of lipid mediators revealed increased arachidonic acid (AA) and 12-LOX metabolites. Whereas treatment of control HEEs with AA increased expression of inflammatory cytokines, 12-HETE attenuated expression of late differentiation markers. Thus, FLG mutations lead to alterations in epidermal eicosanoid metabolism that could serve as an autocrine trigger of inflammation and impaired late epidermal differentiation in AD. In the second part, we established models of epidermal barrier impairment using HEEs to stu, presented by Dr. med. univ. Stefan Blunder, Zusammenfassung in deutscher Sprache, Kumulative Dissertation aus einem Artikel, Medizinische Universität Innsbruck, Dissertation, 2017, OeBB, (VLID)2220659

Nearly 85% of radiotherapy patients develop acute radiation dermatitis, which is an inflammatory reaction of the skin at the treatment field and in the surrounding area. The aims of this study were to unravel the mechanisms of radiation-induced inflammatory responses after localized irradiation in a human 3D organotypic skin culture model. This could provide possible inflammatory targets for reduction of skin side effects. 3D organotypic skin cultures were set up and locally irradiated with 225 kVp X-rays, using a combination of full exposure and partial shielding (50%) of the cultures. The secretion of pro-inflammatory cytokines, the phenotype, and the differentiation markers expression of the cultures were assessed up to 10 days postirradiation. The pro-inflammatory transcription factor nuclear factor kappa B (NF-kappa B) and cyclooxygenase-2 (COX-2) pathways have been studied. The results showed fast activation of NF-kappa B, most likely triggered by DNA damage in the irradiated cells, followed by upregulation of p38 MAPK and COX-2 in the irradiated and surrounding, non-irradiated, areas of the 3D cultures. The application of the COX-2 inhibitor sc-236 was effective at reducing the COX-2 mRNA levels 4 h postirradiation. The same inhibitor also suppressed the PGE2 secretion significantly 72 h after the treatment. The expression of a pro-inflammatory phenotype and abnormal differentiation markers of the cultures were also reduced. However, the use of an NF-kappa B inhibitor (Bay 11-7085) did not have the predicted positive effect on the cultures phenotype postirradiation. Radiation-induced pro-inflammatory responses have been observed in the 3D skin model. The activated signaling pathways involved NF-kappa B transcription factor and its downstream target COX-2. Further experiments aiming to suppress the inflammatory response via specific inhibitors showed that COX-2 is a suitable target for reduction of the normal skin inflammatory responses at radiotherapy, while

Background Filaggrin is an epidermal protein that is important for normal skin barrier functions. Up to 10% of Europeans and Asians carry filaggrin gene (FLG) loss-of function mutations that appear to facilitate trans-epidermal penetration of certain chemicals. We previously showed that mutation carriers have higher internal exposure to certain phthalates, compared to controls, and hypothesized that they could have increased trans-epidermal penetration of other chemicals. Objectives We investigated exposure to non-persistent chemicals in young Danish men with and without FLG mutations. Methods Concentrations of eight simple phenols, six parabens and nine UV filters were analysed in urine from 65 FLG loss-of-function mutation carriers and 130 non-carriers (controls). Regression analyses, controlling for urinary dilution and confounders, were performed to estimate associations between FLG mutation status and chemical concentrations in urine. Results FLG mutation carriers had 80% (13–180%) higher urinary concentrations of methyl paraben (MeP) and 91% (13–219%) higher concentrations of n-propyl paraben (n-PrP) than controls. For 13 compounds, levels were higher in FLG mutation carriers, although differences were only statistically significant for MeP and n-PrP. Combined statistical analysis of concentrations of all the 18 compounds that were detectable in > 10% of subjects, suggested that concentrations were generally higher in mutation carriers (p = 0.03). Conclusion FLG loss-of-function mutation carriers have a higher internal exposure to some non-persistent chemicals, independently of atopic dermatitis. This may be due to increased trans-epidermal absorption and/or higher exposure, and mutation carriers may constitute a group susceptible to increased absorption of chemicals and topical medication.

Essentials FLG mutations cause atopic dermatitis, previously found to be associated with ischemic stroke. Association between FLG mutations and ischemic stroke was examined in 97 174 Danish individuals. FLG mutations were associated with increased ischemic stroke risk in the general population. The association was most pronounced in younger individuals, and in current and former smokers. Summary: Background Heritability studies have shown a considerable genetic component to ischemic stroke risk; however, much is unknown as to which genes are responsible. Also, previous studies have found an association between atopic dermatitis and increased ischemic stroke risk. Objective To test the hypothesis that FLG loss-of-function mutations, known to be associated with atopic dermatitis, were also associated with ischemic stroke. Methods A total of 97 174 individuals, with 3597 cases of ischemic stroke, from the Copenhagen General Population Study, the Copenhagen City Heart Study and the Copenhagen Carotid Stroke Study were genotyped for the two most common filaggrin mutations, FLG R501X and FLG 2282del4. Results FLG mutation carriers had an odds ratio for ischemic stroke of 1.15 (95% confidence interval [CI], 1.02–1.30) compared with non-carriers. Risk of ischemic stroke for FLG mutation carriers was higher among individuals aged < 50 years, with an odds ratio of 1.72 (1.11–2.67), compared with non-carriers. When stratified for smoking, ischemic stroke risk was primarily seen in current and former smokers, with an odds ratio of 1.25 (1.08–1.44). FLG mutations were not associated with conventional cardiovascular risk factors except for slightly more pack-years smoked among mutation carriers, but were associated with increased risk of self-reported eczema, with an odds ratio of 1.42 (1.32–1.52). Finally, self-reported eczema was associated with increased ischemic stroke risk, with an age and sex adjusted hazard ratio of 1.24 (1.01–1.52); however, the association was not

Background Atopic dermatitis (AD) is caused by a complex interplay between immune and barrier abnormalities. Murine models of AD are essential for preclinical assessments of new treatments. Although many models have been used to simulate AD, their transcriptomic profiles are not fully understood, and a comparison of these models with the human AD transcriptomic fingerprint is lacking. Objective We sought to evaluate the transcriptomic profiles of 6 common murine models and determine how they relate to human AD skin. Methods Transcriptomic profiling was performed by using microarrays and quantitative RT-PCR on biopsy specimens from NC/Nga, flaky tail, Flg-mutated, ovalbumin-challenged, oxazolone-challenged, and IL-23–injected mice. Gene expression data of patients with AD, psoriasis, and contact dermatitis were obtained from previous patient cohorts. Criteria of a fold change of 2 or greater and a false discovery rate of 0.05 or less were used for gene arrays. Results IL-23–injected, NC/Nga, and oxazolone-challenged mice show the largest homology with our human meta-analysis–derived AD transcriptome (37%, 18%, 17%, respectively). Similar to human AD, robust TH1, TH2, and also TH17 activation are seen in IL-23–injected and NC/Nga mice, with similar but weaker inflammation in ovalbumin-challenged mice. Oxazolone-challenged mice show a TH1-centered reaction, and flaky tail mice demonstrate a strong TH17 polarization. Flg-mutated mice display filaggrin downregulation without significant inflammation. Conclusion No single murine model fully captures all aspects of the AD profile; instead, each model reflects different immune or barrier disease aspects. Overall, among the 6 murine models, IL-23–injected mice best simulate human AD; still, the translational focus of the investigation should determine which model is most applicable.

Epidermal filaggrin level is affected by ultraviolet B irradiation in animal and experimental models. This study examined the effect of ultraviolet B irradiation on epidermal filaggrin and natural moisturizing factors in vivo in healthy adults (n = 22). Participants were irradiated with 2 minimal erythema doses of ultraviolet B on the skin. Biopsies and tape strips were collected from skin irradiated 24 and 72 h earlier and from nonirradiated skin (control). Real-time quantitative PCR on skin biopsies showed significantly reduced profilaggrin mRNA expression 24 h after irradiation (mean relative mRNA expression ± standard deviation: control, 3.86 ± 2.06 vs. 24 h, 1.52 ± 0.640; p = 0.02; n = 8). Immunohistochemistry showed aberrant spatial distribution of filaggrin protein 72 h after irradiation (n = 3). High-pressure liquid chromatography of tape extracts showed no change in mean total natural moisturizing factor levels after irradiation, but mean trans-urocanic acid was significantly reduced, as expected (n = 8). In conclusion, erythemal doses of ultraviolet B exert acute effects on profilaggrin mRNA and filaggrin protein in human skin in vivo.

Background: Atopic dermatitis (AD) is a multifactorial skin disease with waxing and waning inflammatory process. In recent years, genetic mutations namely the null mutations of the filaggrin gene (FLG) has been the focus in AD risk factors investigations. Purpose: To highlight the emerging topic on the role of filaggrin as an important element in the pathogenesis of AD. Reviews: Filaggrin binds to cytoskeleton keratin to bring the physical strength to corneocytes. Filaggrin will be degraded to amino acids that conserve acidic pH and condensation of the skin. Patients with FLG null mutations are more likely to experience early-onset, severe and persistent AD. AD patients with FLG R501X null mutations are reported to be the least responsive to therapy. Conclusion: A filaggrin deficit is the main culprit in AD development that eventually leads to the defective skin barriers, reduction in natural moisturizing factors (NMF), infections and inflammation. FLG mutations associates with the phenotypes and course of AD which could be examined using Raman-determined NMF.

Background: Atopic dermatitis (AD) is a multifactorial skin disease with waxing and waning inflammatory process. In recent years, genetic mutations namely the null mutations of the filaggrin gene (FLG) has been the focus in AD risk factors investigations. Purpose: To highlight the emerging topic on the role of filaggrin as an important element in the pathogenesis of AD. Reviews: Filaggrin binds to cytoskeleton keratin to bring the physical strength to corneocytes. Filaggrin will be degraded to amino acids that conserve acidic pH and condensation of the skin. Patients with FLG null mutations are more likely to experience early-onset, severe and persistent AD. AD patients with FLG R501X null mutations are reported to be the least responsive to therapy. Conclusion: A filaggrin deficit is the main culprit in AD development that eventually leads to the defective skin barriers, reduction in natural moisturizing factors (NMF), infections and inflammation. FLG mutations associates with the phenotypes and course of AD which could be examined using Raman-determined NMF.

Epidermal filaggrin level is affected by ultraviolet B irradiation in animal and experimental models. This study examined the effect of ultraviolet B irradiation on epidermal filaggrin and natural moisturizing factors in vivo in healthy adults (n = 22). Participants were irradiated with 2 minimal erythema doses of ultraviolet B on the skin. Biopsies and tape strips were collected from skin irradiated 24 and 72 h earlier and from nonirradiated skin (control). Real-time quantitative PCR on skin biopsies showed significantly reduced profilaggrin mRNA expression 24 h after irradiation (mean relative mRNA expression ± standard deviation: control, 3.86 ± 2.06 vs. 24 h, 1.52 ± 0.640; p = 0.02; n = 8). Immunohistochemistry showed aberrant spatial distribution of filaggrin protein 72 h after irradiation (n = 3). High-pressure liquid chromatography of tape extracts showed no change in mean total natural moisturizing factor levels after irradiation, but mean trans-urocanic acid was significantly reduced, as expected (n = 8). In conclusion, erythemal doses of ultraviolet B exert acute effects on profilaggrin mRNA and filaggrin protein in human skin in vivo.

Atopic dermatitis (AD) is caused by a complex interplay between immune and barrier abnormalities. Murine models of AD are essential for preclinical assessments of new treatments. While many models have been used to simulate AD, their transcriptomic profiles are not fully understood, and a comparison of these models with the human AD transcriptomic fingerprint is lacking. We sought to evaluate the transcriptomic profiles of six common murine models and determine how they relate to human AD skin. Transcriptomic profiling was performed using microarrays and qRT-PCR on biopsies from NC/Nga, flaky-tail, Flg-mutated, ovalbumin-challenged, oxazolone-challenged, and IL-23-injected mice. Gene expression data of AD, psoriasis, and contact dermatitis were obtained from previous patient cohorts. Criteria of fold-change/FCH≥2 and false discovery rate/FDR≤0.05 were used for gene arrays. IL-23-injected, NC/Nga, and oxazolone-challenged mice show the largest homology with our human meta-analysis derived AD (MADAD) transcriptome (37%, 18%, 17%, respectively). Similar to human AD, robust Th1, Th2, and also Th17 activation are seen in IL-23-injected and NC/Nga mice, with similar, but weaker, inflammation in ovalbumin-challenged mice. Oxazolone-challenged mice show a Th1-centered reaction and flaky-tail mice demonstrate a strong Th17 polarization. Flg-mutated mice display FLG down-regulation without significant inflammation. No single murine model fully captures all aspects of the AD profile; instead, each model reflects different immune or barrier disease aspects. Overall, among the six murine models, IL-23-injected mice best simulate human AD; still, the translational focus of the investigation should determine which model is most applicable. When testing new drugs for atopic dermatitis, murine models might be used to study barrier or immune features, but human trials are needed to determine effects on actual disease profile.

Background: Neutralization of stratum corneum (SC) pH, which is induced by a variety of stimuli, such as scratching, use of soap and inflammation, can stimulate activity of serine protease (SPase). Activation of SPase induces production of thymic stromal lymphopoietin (TSLP) through protease-activated receptor-2. Both reduced expression of natural moisturizing factors, which are required for maintenance of SC pH, and the preferential development of atopic dermatitis (AD)-like dermatitis are found in flaky-tail mice (FTM) with a loss-of-function mutation in filaggrin., Objective: We examined possible correlations between disturbance of responses to an exogenous stimulus of SC neutralization and the preferential emergence of AD-like dermatitis in FTM., Methods: FTM and wild-type mice (C57BL/6) were subjected to an SC-neutralization stimulus via application of 1,1,3,3-tetramethylguanidine (TMG). TMG was applied to young mice at a time when FTM had not yet developed significant dermatitis, and we examined their ability to maintain SC acidity and several parameters associated with AD-like dermatitis., Results: The recovery of SC pH after the application of TMG was delayed in FTM, presumably because of unchanged expression of Na+/H+ antiporter 1, which is involved in maintenance of SC acidity. Cutaneous inflammation with elevated SPase activity and serum levels of TSLP, thymus and activation-regulated chemokine and IgE were induced only in TMG-treated FTM., Conclusion: Our results suggest that defective maintenance of pH of SC is correlated with emergence and exacerbation of AD-like dermatitis in FTM., 博士(医学), 大分大学

The evolution of human skin pigmentation must address both the initial evolution of intense epidermal pigmentation in hominins, and its subsequent dilution in modern humans. While many authorities believe that epidermal pigmentation evolved to protect against either ultraviolet B (UV-B) irradiation-induced mutagenesis or folic acid photolysis, we hypothesize that pigmentation augmented the epidermal barriers by shifting the UV-B dose-response curve from toxic to beneficial. Whereas erythemogenic UV-B doses produce apoptosis and cell death, suberythemogenic doses benefit permeability and antimicrobial function. Heavily melanized melanocytes acidify the outer epidermis and emit paracrine signals that augment barrier competence. Modern humans, residing in the cooler, wetter climes of south-central Europe and Asia, initially retained substantial pigmentation. While their outdoor lifestyles still permitted sufficient cutaneous vitamin D3 (VD3) synthesis, their marginal nutritional status, coupled with cold-induced caloric needs, selected for moderate pigment reductions that diverted limited nutritional resources towards more urgent priorities (=metabolic conservation). The further pigment-dilution that evolved as humans reached north-central Europe (i.e., northern France, Germany), likely facilitated cutaneous VD3 synthesis, while also supporting ongoing, nutritional requirements. But at still higher European latitudes where little UV-B breaches the atmosphere (i.e., present-day UK, Scandinavia, Baltic States), pigment dilution alone could not suffice. There, other nonpigment-related mutations evolved to facilitate VD3 production; for example, in the epidermal protein, filaggrin, resulting in reduced levels of its distal metabolite, trans-urocanic acid, a potent UV-B chromophore. Thus, changes in human pigmentation reflect a complex interplay between latitude, climate, diet, lifestyle, and shifting metabolic priorities.

The crosslinked envelope of the mammalian epidermal corneocyte serves as a scaffold for assembly of the lipid barrier of the epidermis. Thus, deficient envelope crosslinking by keratinocyte transglutaminase (TGM1) is a major cause of the human autosomal recessive congenital ichthyoses characterized by barrier defects. Expectations that loss of some envelope protein components would also confer an ichthyosis phenotype have been difficult to demonstrate. To help rationalize this observation, the protein profile of epidermis from loricrin knockout mice has been compared to that of wild type. Despite the mild phenotype of the knockout, some 40 proteins were incorporated into envelope material to significantly different extents compared to those of wild type. Nearly half were also incorporated to similarly altered extents into the disulfide bonded keratin network of the corneocyte. The results suggest that loss of loricrin alters their incorporation into envelopes as a consequence of protein-protein interactions during cell maturation. Mass spectrometric protein profiling revealed that keratin 1, keratin 10, and loricrin are prominent envelope components and that dozens of other proteins are also components. This finding helps rationalize the potential formation of functional envelopes, despite loss of a single component, due to the availability of many alternative transglutaminase substrates.

Цель: изучить влияние мутаций гена филагрина (FLG) на особенности течения и характеристики кожи (параметры корнеометрии) у детей с атопическим дерматитом (АД).Пациенты и методы. В исследование были включены 30 детей в возрасте от 3 до 11 лет с АД. Наряду с клиническим обследованием проводился молекулярно-генетический анализ для выявления мутаций FLG. Увлажненность кожи измеряли методом корнеометрии.Результаты. Мутации FLG выявлены у 43,29% детей. Доказана прямая корреляционная связь между наличием мутаций FLG и снижением увлажненности кожи. Клинические особенности АД характеризуются ранним дебютом и преимущественно среднетяжелым течением заболевания.Выводы. Доказано влияния выявленных мутаций FLG на клиническое течение АД, особенно на показатели увлажненности кожи, что необходимо учитывать при составлении персонифицированной схемы лечения.Ключевые слова: атопический дерматит, дети, филагрин, корнеометрия., Мета: визначити вплив мутацій гена філагрину (FLG) на особливості перебігу та характеристики шкіри (параметри корнеометрії) у дітей з атопічним дерматитом (АД).Пацієнти і методи. У дослідження було включено 30 дітей віком від 3 до 11 років з АД. Поряд з клінічним обстеженням проводився молекулярно-генетичний аналіз для виявлення мутацій FLG. Зволоження шкіри вимірювали методом корнеометрії.Результати. Мутації FLG виявлено у 43,29% дітей. Доведено прямий кореляційний зв'язок між наявністю мутацій FLG та зниженням зволоженості шкіри. Клінічні особливості АД характеризуються раннім дебютом та переважно середньоважким перебігом захворювання.Висновки. Доведено вплив виявлених мутацій FLG на клінічний перебіг АД, особливо на показники зволоженості шкіри, що необхідно враховувати при складанні персоніфікованої схеми лікування.Ключові слова: атопічний дерматит, діти, філагрин, корнеометрія., Purpose of the study.To study the effect of the filaggrin gene (FLG) mutations on disease characteristics and the skin parameters in children with atopic dermatitis (AD).Materials and methods. 30 children with age from 3 to 11 years with AD were included in the study. Molecular genetic analysis was performed to identify the mutations of FLG together with the children clinical examination. The skin moisture was examined using corneometer method.Results. Mutations in the gene filaggrin were detected in 43.29% of children. Direct correlation was proven between the presence of FLG mutations and reduction of skin moisture. Clinical signs of AD are distinguished by early onset and predominantly moderate severity of the disease.Conclusions. Influence of identified FLG mutations on the dermatitis clinical course was proven, especially the relation to skin moisture indicators. It is necessary to take into account during creation of individual treatment schemes.Key words: atopic dermatitis, children, filaggrin, corneometery.

The evolution of human skin pigmentation must address both the initial evolution of intense epidermal pigmentation in hominins, and its subsequent dilution in modern humans. While many authorities believe that epidermal pigmentation evolved to protect against either ultraviolet B (UV-B) irradiation-induced mutagenesis or folic acid photolysis, we hypothesize that pigmentation augmented the epidermal barriers by shifting the UV-B dose-response curve from toxic to beneficial. Whereas erythemogenic UV-B doses produce apoptosis and cell death, suberythemogenic doses benefit permeability and antimicrobial function. Heavily melanized melanocytes acidify the outer epidermis and emit paracrine signals that augment barrier competence. Modern humans, residing in the cooler, wetter climes of south-central Europe and Asia, initially retained substantial pigmentation. While their outdoor lifestyles still permitted sufficient cutaneous vitamin D3 (VD3) synthesis, their marginal nutritional status, coupled with cold-induced caloric needs, selected for moderate pigment reductions that diverted limited nutritional resources towards more urgent priorities (=metabolic conservation). The further pigment-dilution that evolved as humans reached north-central Europe (i.e., northern France, Germany), likely facilitated cutaneous VD3 synthesis, while also supporting ongoing, nutritional requirements. But at still higher European latitudes where little UV-B breaches the atmosphere (i.e., present-day UK, Scandinavia, Baltic States), pigment dilution alone could not suffice. There, other nonpigment-related mutations evolved to facilitate VD3 production; for example, in the epidermal protein, filaggrin, resulting in reduced levels of its distal metabolite, trans-urocanic acid, a potent UV-B chromophore. Thus, changes in human pigmentation reflect a complex interplay between latitude, climate, diet, lifestyle, and shifting metabolic priorities.

The crosslinked envelope of the mammalian epidermal corneocyte serves as a scaffold for assembly of the lipid barrier of the epidermis. Thus, deficient envelope crosslinking by keratinocyte transglutaminase (TGM1) is a major cause of the human autosomal recessive congenital ichthyoses characterized by barrier defects. Expectations that loss of some envelope protein components would also confer an ichthyosis phenotype have been difficult to demonstrate. To help rationalize this observation, the protein profile of epidermis from loricrin knockout mice has been compared to that of wild type. Despite the mild phenotype of the knockout, some 40 proteins were incorporated into envelope material to significantly different extents compared to those of wild type. Nearly half were also incorporated to similarly altered extents into the disulfide bonded keratin network of the corneocyte. The results suggest that loss of loricrin alters their incorporation into envelopes as a consequence of protein-protein interactions during cell maturation. Mass spectrometric protein profiling revealed that keratin 1, keratin 10, and loricrin are prominent envelope components and that dozens of other proteins are also components. This finding helps rationalize the potential formation of functional envelopes, despite loss of a single component, due to the availability of many alternative transglutaminase substrates.

The skin constitutes the interface between the organism and the environment, and it protects the body from harmful substances in the environment via physical, chemical and immunological barriers. The immunological barrier of the skin comprises both cells from the innate and the adaptive immune system. During the last years, it has become clear that innate lymphoid cells play a role in homeostasis and inflammation of the skin in humans and mice. In this review, we will discuss the role of innate lymphoid cells in healthy and inflamed skin with special focus on their role in atopic dermatitis.

Мета. Метою даного дослідження було визначити зв’язок однонуклеотидного поліморфізму в гені філагрину й експресії мРНК філагрину в букальному епітелії з фенотипом бронхіальної астми з атопічним дерматитом в анамнезі у дітей. Методи. Генотипування філагрину (rs11204981) проводили в групі хворих із бронхіальною астмою і контрольній групі за допомогою ПЛР у реальному часі. Рівень експресії мРНК оцінювався з використанням зворотної транскрипції та наступної ПЛР у реальному часі. Результати. Ми виявили, що 5 % пацієнтів основної групи і 2 % контрольної групи мали мінорну алель (АА), 27 і 36 % відповідно мали гетерозиготну алель, 67 і 61 % відповідно — мажорну алель. Варіанти з генотипом АА з rs11204981 FLG виявилися в 2,4 раза частіше у пацієнтів основної, ніж контрольної групи. Гетерозиготний варіант мав значно вищу експресію філагрину в букальному епітелії. Висновки. Ми вважаємо, що поліморфізм в гені філагрину (rs11204981) може служити як важливий прогностичний маркер для фенотипу бронхіальної астми та атопічного дерматиту і що високий рівень експресії в гетерозиготному стані може свідчити про протекторну роль даного генотипу у розвитку алергії., Цель. Целью данного исследования было определить связь однонуклеотидного полиморфизма в гене филаггрина и экспрессии мРНК филаггрина в буккальном эпителии с фенотипом бронхиальной астмы и атопическим дерматитом в анамнезе у детей. Методы. Генотипирование филаггрина (rs11204981) проводили в группе больных с бронхиальной астмой и контрольной группе с помощью ПЦР в реальном времени. Уровень экспрессии мРНК оценивался с использованием обратной транскрипции и последующей ПЦР в реальном времени. Результаты. Мы обнаружили, что 5 % пациентов основной группы и 2 % контрольной группы имели минорную аллель (AA), 27 и 36 % соответственно имели гетерозиготную аллель, 67 и 61 % соответственно имели мажорную аллель. Варианты с генотипом АА с rs11204981 встречались в 2,4 раза чаще у пациентов основной, чем контрольной группы. Гетерозиготный вариант имел значительно более высокую экспрессию филаггрина в буккальном эпителии. Выводы. Мы считаем, что полиморфизм в гене филаггрина (rs11204981) может служить в качестве важного прогностического маркера для фенотипа бронхиальной астмы и атопического дерматита, и высокий уровень экспрессии в гетерозиготном состоянии может свидетельствовать о протекторной роли данного генотипа в развитии аллергии., Objective. The objective of this study was to determine the correlation between single-nucleotide polymorphism in filaggrin gene and expression of filaggrin mRNA in buccal epithelium and the phenotype of bronchial asthma with atopic dermatitis in medical history of children. Methods. Filaggrin genotyping (rs11204981) was carried out in group of patients with bronchial asthma and control group using real-time polymerase chain reaction (PCR). The level of mRNA expression was assessed by reverse transcription and subsequent real-time PCR. Results. We have found that 5 % of patients in the study group and 2 % in the control group had a minor allele (AA), 27 and 36 %, respectively, — heterozygous allele (GA), 67 and 61 % — major allele (GG). Variants with the AA genotype of the FLG rs11204981 were found 2.4 times more often in patients from the study group than in controls. Heterozygous variant had significantly higher expression in filaggrin in buccal epithelium. Conclusions. We believe that polymorphism in filaggrin gene (rs11204981) can serve as an important prognostic marker for the phenotype of bronchial asthma and atopic dermatitis, and that high levels of expression in the heterozygous state may indicate the protective role of this genotype in the development of allergy.

Skin pigmentation lightened progressively to a variable extent, as modern humans emigrated out of Africa, but extreme lightening occurred only in northern Europeans. Yet, loss of pigmentation alone cannot suffice to sustain cutaneous vitamin D3 (VD3) formation at the high latitudes of northern Europe. We hypothesized that loss-of-function mutations in the epidermal structural protein, filaggrin (FLG), could have evolved to sustain adequate VD3 status. Loss of FLG results in reduced generation of trans-urocanic acid, the principal endogenous ultraviolet-B (UV-B) filter in lightly-pigmented individuals. Accordingly, we identified a higher prevalence of FLG mutations in northern European populations when compared to more southern European, Asian and African populations that correlates significantly with differences in circulating 25-OH-VD3 levels in these same populations. By allowing additional UV-B penetration and intracutaneous VD3 formation, the latitude-dependent gradient in FLG mutations, likely together with other concurrent mutations in VD3 metabolic pathways, provide a non-pigment-based mechanism that sustains higher levels of circulating VD3 in northern Europeans. At the time that FLG mutations evolved, xerosis due to FLG deficiency was a lesser price to pay for enhanced VD3 production. Yet, the increase in FLG mutations has inadvertently contributed to an epidemic of atopic diseases that has emerged in recent decades.

Skin pigmentation lightened progressively to a variable extent, as modern humans emigrated out of Africa, but extreme lightening occurred only in northern Europeans. Yet, loss of pigmentation alone cannot suffice to sustain cutaneous vitamin D3 (VD3) formation at the high latitudes of northern Europe. We hypothesized that loss-of-function mutations in the epidermal structural protein, filaggrin (FLG), could have evolved to sustain adequate VD3 status. Loss of FLG results in reduced generation of trans-urocanic acid, the principal endogenous ultraviolet-B (UV-B) filter in lightly-pigmented individuals. Accordingly, we identified a higher prevalence of FLG mutations in northern European populations when compared to more southern European, Asian and African populations that correlates significantly with differences in circulating 25-OH-VD3 levels in these same populations. By allowing additional UV-B penetration and intracutaneous VD3 formation, the latitude-dependent gradient in FLG mutations, likely together with other concurrent mutations in VD3 metabolic pathways, provide a non-pigment-based mechanism that sustains higher levels of circulating VD3 in northern Europeans. At the time that FLG mutations evolved, xerosis due to FLG deficiency was a lesser price to pay for enhanced VD3 production. Yet, the increase in FLG mutations has inadvertently contributed to an epidemic of atopic diseases that has emerged in recent decades.

Atopic dermatitis (AD) is a chronic, pruritic, inflammatory dermatosis that affects up to 25% of children and 2% to 3% of adults. This guideline addresses important clinical questions that arise in the management and care of AD, providing updated and expanded recommendations based on the available evidence. In this first of 4 sections, methods for the diagnosis and monitoring of disease, outcomes measures for assessment, and common clinical associations that affect patients with AD are discussed. Known risk factors for the development of disease are also reviewed.

Chronic exposure to 2,3,7,8-tetrachlorodibeno-p-dioxin (TCDD) and related polyhalogenated organic pollutants occurs as a consequence of modern life. Exploring the cellular basis for their action is anticipated to help understand the risk they pose and improve the foundation for their regulation. A basis for the striking change in human keratinocyte colony morphology due to TCDD exposure has been investigated by shotgun proteomics. Concentrating on changes in protein levels among three cell strains has revealed significant decreases in the differentiation markers filaggrin, keratin 1, and keratin 10. EGF treatment in concert with TCDD enhanced the changes in these markers and several other proteins while reducing the levels of certain other proteins. The only protein stimulated by TCDD in all three strains and reversed by EGF in them was vimentin, not previously observed to be in the aryl hydrocarbon receptor response domain. Although TCDD is often proposed to enhance keratinocyte differentiation, proteomic analysis reveals it uncouples the differentiation program and suggests that reduced levels of differentiation marker proteins contribute to the observed excessive stratification it induces.

BackgroundAtopic dermatitis (AD) is a major inflammatory condition of the skin caused by inherited skin barrier deficiency, with mutations in the filaggrin gene predisposing to development of AD. Support for barrier deficiency initiating AD came from flaky tail mice, which have a frameshift mutation in Flg and also carry an unknown gene, matted, causing a matted hair phenotype.ObjectiveWe sought to identify the matted mutant gene in mice and further define whether mutations in the human gene were associated with AD.MethodsA mouse genetics approach was used to separate the matted and Flg mutations to produce congenic single-mutant strains for genetic and immunologic analysis. Next-generation sequencing was used to identify the matted gene. Five independently recruited AD case collections were analyzed to define associations between single nucleotide polymorphisms (SNPs) in the human gene and AD.ResultsThe matted phenotype in flaky tail mice is due to a mutation in the Tmem79/Matt gene, with no expression of the encoded protein mattrin in the skin of mutant mice. Matt(ft) mice spontaneously have dermatitis and atopy caused by a defective skin barrier, with mutant mice having systemic sensitization after cutaneous challenge with house dust mite allergens. Meta-analysis of 4,245 AD cases and 10,558 population-matched control subjects showed that a missense SNP, rs6684514, [corrected] in the human MATT gene has a small but significant association with AD.ConclusionIn mice mutations in Matt cause a defective skin barrier and spontaneous dermatitis and atopy. A common SNP in MATT has an association with AD in human subjects.

BackgroundAtopic dermatitis (AD) is a major inflammatory condition of the skin caused by inherited skin barrier deficiency, with mutations in the filaggrin gene predisposing to development of AD. Support for barrier deficiency initiating AD came from flaky tail mice, which have a frameshift mutation in Flg and also carry an unknown gene, matted, causing a matted hair phenotype.ObjectiveWe sought to identify the matted mutant gene in mice and further define whether mutations in the human gene were associated with AD.MethodsA mouse genetics approach was used to separate the matted and Flg mutations to produce congenic single-mutant strains for genetic and immunologic analysis. Next-generation sequencing was used to identify the matted gene. Five independently recruited AD case collections were analyzed to define associations between single nucleotide polymorphisms (SNPs) in the human gene and AD.ResultsThe matted phenotype in flaky tail mice is due to a mutation in the Tmem79/Matt gene, with no expression of the encoded protein mattrin in the skin of mutant mice. Matt(ft) mice spontaneously have dermatitis and atopy caused by a defective skin barrier, with mutant mice having systemic sensitization after cutaneous challenge with house dust mite allergens. Meta-analysis of 4,245 AD cases and 10,558 population-matched control subjects showed that a missense SNP, rs6684514, [corrected] in the human MATT gene has a small but significant association with AD.ConclusionIn mice mutations in Matt cause a defective skin barrier and spontaneous dermatitis and atopy. A common SNP in MATT has an association with AD in human subjects.

Chronic exposure to 2,3,7,8-tetrachlorodibeno-p-dioxin (TCDD) and related polyhalogenated organic pollutants occurs as a consequence of modern life. Exploring the cellular basis for their action is anticipated to help understand the risk they pose and improve the foundation for their regulation. A basis for the striking change in human keratinocyte colony morphology due to TCDD exposure has been investigated by shotgun proteomics. Concentrating on changes in protein levels among three cell strains has revealed significant decreases in the differentiation markers filaggrin, keratin 1, and keratin 10. EGF treatment in concert with TCDD enhanced the changes in these markers and several other proteins while reducing the levels of certain other proteins. The only protein stimulated by TCDD in all three strains and reversed by EGF in them was vimentin, not previously observed to be in the aryl hydrocarbon receptor response domain. Although TCDD is often proposed to enhance keratinocyte differentiation, proteomic analysis reveals it uncouples the differentiation program and suggests that reduced levels of differentiation marker proteins contribute to the observed excessive stratification it induces.