Immune Response In Atopic Dermatitis Research Articles

Topical delivery of baricitinib-impregnated nanoemulgel: a promising platform for inhibition of JAK -STAT pathway for the effective management of atopic dermatitis.

Baricitinib, an inhibitor of Janus kinase 1/2 receptors majorly involved in the dysregulation of immune responses in atopic dermatitis, is currently approved for managing atopic dermatitis in Europe. The delivery of baricitinib through oral route is associated to several adverse effects due to off-target effects. Therefore, the current study is aimed at formulation of baricitinib loaded nanoemulgel for evaluation of topical delivery potential in the treatment of atopic dermatitis. The baricitinib-loaded nanoemulsions (0.05 and 0.1% w/w) revealed an average globule size of 162.86 ± 0.37 and 173.66 ± 4.88nm respectively with narrow PDI. The optimized batch of baricitinib nanoemulsion was converted to nanoemulgel by the addition of the mixture of gel bases SEPINEO™ DERM and SEPINEO™ P 600 along with propylene glycol, resulting in pseudoplastic shear thinning behaviour. The optimized nanoemulgels have shown prominent retention of baricitinib in the skin along with permeation. The skin distribution study of coumarin-6 loaded nanoemulgel demonstrated high fluorescence in the epidermal layer. The western blot analysis revealed significant inhibition of phosphorylated signal transducers and activators of transcriptions 1 (##p < 0.01) and 3 (#p < 0.05) by application of 0.05 and 0.1% baricitinib nanoemulgel. The baricitinib nanoemulgels have shown anti-inflammatory activity by significantly reducing expressions of various inflammatory markers. Histopathological analysis of skin tissues treated with baricitinib nanoemulgel has demonstrated a marked reduction in acanthosis, hyperkeratosis, and intact outer epidermis. These results supported the potential role of baricitinib-loaded nanoemulgel in reducing the inflammation and disease severity associated with atopic dermatitis.

The Association between Gut Microbiota and Serum Biomarkers in Children with Atopic Dermatitis.

Background. Currently, it is known that the gut microbiota plays an important role in the functioning of the immune system, and a rebalancing of the bacterial community can arouse complex immune reactions and lead to immune-mediated responses in an organism, in particular, the development of atopic dermatitis (AD). Cytokines and chemokines are regulators of the innate and adaptive immune response and represent the most important biomarkers of the immune system. It is known that changes in cytokine profiles are a hallmark of many diseases, including atopy. However, it remains unclear how the bacterial imbalance disrupts the function of the immune response in AD. Objectives. We attempted to determine the role of gut bacteria in modulating cytokine pathways and their role in atopic inflammation. Methods. We sequenced the 16S rRNA gene from 50 stool samples of children aged 3-12 years who had confirmed atopic dermatitis, and 50 samples from healthy children to serve as a control group. To evaluate the immune status, we conducted a multiplex immunofluorescence assay and measured the levels of 41 cytokines and chemokines in the serum of all participants. Results. To find out whether changes in the composition of the gut microbiota were significantly associated with changes in the level of inflammatory cytokines, a correlation was calculated between each pair of bacterial family and cytokine. In the AD group, 191 correlations were significant (Spearman's correlation coefficient, p ≤ 0.05), 85 of which were positive and 106 which were negative. Conclusions. It has been demonstrated that intestinal dysbiosis is associated with alterations in cytokine profiles, specifically an increase in proinflammatory cytokine concentrations. This may indicate a systemic impact of these conditions, leading to an imbalance in the immune system's response to the Th2 type. As a result, atopic conditions may develop. Additionally, a correlation between known AD biomarkers (IL-5, IL-8, IL-13, CCL22, IFN-γ, TNF-α) and alterations in the abundance of bacterial families (Pasteurellaceae, Barnesiellaceae, Eubacteriaceae) was observed.

61 Influence of dupilumab on HSV-specific immune response in atopic dermatitis

61 Influence of dupilumab on HSV-specific immune response in atopic dermatitis

Dupilumab strengthens herpes simplex virus type 1–specific immune responses in atopic dermatitis

Impaired virus clearance in a subgroup of atopic dermatitis (AD) patients can lead to severe herpes simplex virus (HSV) infections called eczema herpeticum (EH). We recently identified a type 2 skewed viral immune response in EH patients. Clinical data suggest a reduced incidence of EH in AD patients treated with dupilumab, although immunologic investigations of this phenomenon are still lacking. We examined the impact of dupilumab on the HSV type 1 (HSV-1) specific immune response in AD, focusing on patients with (ADEH+) and without (ADEH-) a history of EH. Sera and peripheral blood mononuclear cells were collected from ADEH+ and ADEH- patients, a subgroup of whom was receiving dupilumab treatment, and healthy controls. Serum samples were tested for IgE against HSV-1 glycoprotein D (n= 85). Peripheral blood mononuclear cells were stimulated with HSV peptides, and activated CD4+ and CD8+ cells were characterized by flow cytometry after magnetic enrichment via CD154 or CD137 (n= 60). Cytokine production of HSV-1-reactive T-cell lines (n= 33) and MHC-I tetramer+ (HSV-1-UL25) CD8+ T cells was investigated by bead assay and intracellular cytokine staining (n= 21). We confirmed that HSV-1-specific IgE is elevated in ADEH+ patients. During dupilumab treatment, the IgE levels were significantly decreased, reaching levels of healthy controls. HSV-1-specific TC1 frequencies were elevated in ADEH- patients treated with dupilumab compared to dupilumab-negative patients. There were no changes in the frequencies of HSV-1-specific TH cells while receiving dupilumab therapy. AD patients receiving dupilumab exhibited elevated IFN-γ and reduced IL-4 production in HSV-1-UL25-epitope-specific T cells compared to dupilumab-negative patients. Dupilumab may improve the HSV-1-specific immune response in AD as a result of an increased type I immune response and a reduction of HSV-1-specific IgE.

1119 Benvitimod alleviates the Type 2 immune responses in atopic dermatitis by restraining group 2 innate lymphoid cells

1119 Benvitimod alleviates the Type 2 immune responses in atopic dermatitis by restraining group 2 innate lymphoid cells

MiRNA expression profiles of the perilesional skin of atopic dermatitis and psoriasis patients are highly similar

Atopic dermatitis (AD) and psoriasis vulgaris (PV) are chronic inflammatory skin diseases with heterogeneous molecular backgrounds. MicroRNAs (miRNAs) contribute to either development or regulation of many immune system related diseases. Only few miRNA profiling studies are available for AD and no comparisons between AD and PV skin miRNA profiles have been performed recently. We conducted a miRNA profiling analysis of skin, as well as serum, from adult AD and PV patients and control individuals. 130 miRNAs were differentially expressed in AD skin, of which 77 were common differentially expressed in AD and PV. No differentially expressed miRNAs were detected in serum. Pathway analyses revealed differentially expressed miRNAs to potentially target immune-system related pathways, including TNF-α, IL-2/STAT4 and IL-6/JAK/STAT3. Additional genetic analysis of published AD GWAS dataset detected association of several target genes of differentially expressed miRNAs in skin. Moreover, miR-28-5p, miR-31-5p, miR-378a-3p and miR-203a were validated as upregulated in the skin of AD and PV patients. All validated miRNAs were reliable predictive markers for AD or PV. In conclusion, miRNA expression pattern in the skin of adult AD patients is highly similar to that of PV with multiple differentially expressed miRNAs potentially involved in the regulation of immune responses in AD and PV.

046 Influence of dupilumab on HSV-specific immune response in atopic dermatitis

Eczema herpeticum (EH) is a disseminated, potentially life-threatening HSV infection in atopic dermatitis (AD) patients. Recently, we showed a type-2 skewed immune response to viruses in EH patients. Dupilumab is a monoclonal antibody targeting the IL-4Ra chain, and therefore acts directly against type-2 inflammation. Molecular investigations examining the impact of dupilumab on the immune defense against viruses are lacking so far. We aimed to analyze the effect of dupilumab on the antiviral response in AD patients with (ADEH+) and without (ADEH-) a history of EH.

371 Dissecting key features of early-stage atopic dermatitis in pre-clinical models

Atopic dermatitis (AD) is a chronic inflammatory skin disease associated with barrier defects and dysbiosis. The development and progression of AD critically depends on the action of type 2 immune cells and mediators, whose identity and chronological appearance in the establishment of AD are still elusive. We aim to disclose the kinetics and cellular contributors of type 2 immune responses in AD, focusing on the dynamics of interleukin (IL)-4 induction during skin inflammation in pre-clinical models.

012 Transcriptomic profiling reveals a pronounced TH22 signature in dupilumab-associated face and neck dermatitis

Dupilumab, a therapeutic antibody that blocks the eczematous type 2 immune response in atopic dermatitis (AD), has shown efficacy in many clinical trials and real-life observational studies. Besides blepharitis and conjunctivitis, the de novo appearance of head-neck dermatitis is recognized as a distinct side effect, occurring in up to 10% of patients at any time after dupilumab initiation. Histopathological features distinct from conventional AD such as psoriasiform hyperplasia or increased numbers of ectatic capillaries suggest a drug effect, but exact underlying mechanisms remain largely unknown.

Single-cell profiles reveal distinctive immune response in atopic dermatitis in contrast to psoriasis.

Understanding the complex orchestrated inflammation in atopic dermatitis (AD), one of the most common chronic inflammatory diseases worldwide, is essential for therapeutic approaches. However, a comparative analysis on the single-cell level of the inflammation signatures correlated with the severity is missing so far. We applied single-cell RNA and T-cell receptor (TCR) sequencing on immune cells enriched from skin biopsies and matched blood samples of AD in comparison with psoriasis (PS) patients. Clonally propagated skin-derived T cells showed disease-specific TCR motifs shared between patients which was more pronounced in PS compared to AD. The disease-specific T-cell clusters were mostly of a Th2/Th22 sub-population in AD and Th17/Tc17 in PS, and their numbers were associated with severity scores in both diseases. Herein, we provide for the first time a list that associates cell type-specific gene expression with the severity of the two most common chronic inflammatory skin diseases. Investigating the cell signatures in the patients´ PBMCs and skin stromal cells, a systemic involvement of type-3 inflammation was clearly detectable in PS circulating cells, while in AD inflammatory signatures were most pronounced in fibroblasts, pericytes, and keratinocytes. Compositional and functional analyses of myeloid cells revealed the activation of antiviral responses in macrophages in association with disease severity in both diseases. Different disease-driving cell types and subtypes which contribute to the hallmarks of type-2 and type-3 inflammatory signatures and are associated with disease activities could be identified by single-cell RNA-seq and TCR-seq in AD and PS.

Assessment of Mucosa-Associated Epithelial Chemokine, Thymus-Expressed Chemokine, Periostin and Zonulin Levels in Infants With Atopic Dermatitis.

Atopic dermatitis (AD) is a chronic inflammatory skin disease. Skin and gut are the organs that first encounter antigens and environmental triggers. The mechanisms behind the relation between skin and gut immune responses in AD have not been identified yet. To investigate mucosa-associated epithelial chemokine (MEC/CCL28), thymus-expressed chemokine (TECK/CCL25), periostin and zonulin levels in infants with AD. Children under one year old participated in the study. We used a propensity matching score. We included 39 infants who had active AD lesions at the time of evaluation. Serum MEC/CCL28, TECK/CCL25, periostin and zonulin levels were measured. We examined age and sex matched 39 infants with AD and 39 healthy infants. Median value of zonulin was lower in infants with AD [49.2 (27.1-71.8) ng/mL] compared to healthy controls [58.5 (27.3-80.8) ng/mL] (P < 0.001). Infants with zonulin levels ≤55.15 ng/mL had 11.64 times more risk of developing AD than the infants with zonulin levels >55.15 ng/mL. Infants whose MEC/CCL28 levels were ≥8.3 ng/mL had 5.83 times more risk of developing AD than the infants with MEC levels <8.3 ng/mL. Duration of AD and SCORAD index score did not show correlation with MEC/CCL28, TECK/CCL25, periostin and zonulin levels. Low zonulin levels and high MEC/CCL28 levels in infants may show an increased association with AD.

017 Unraveling the kinetics and cellular contributions in type 2 immune responses in atopic dermatitis

Atopic dermatitis (AD) is a chronic inflammatory skin disease associated with skin barrier defects and microbial dysbiosis. The development and progression of AD critically depends on the action of type 2 immune cells and mediators. However, the identity of these immune cells as well as their chronological appearance in the establishment of AD are still elusive. This project aims to disclose the kinetics and cellular contributors of type 2 immune responses in AD, focusing on the dynamics of interleukin (IL)-4 induction during skin inflammation in pre-clinical models. To mimic skin barrier impairment, mice were subjected to repeated tape stripping (TS) of their shaved back skin. Medium containing Staphylococcus aureus (S. aureus) was applied to induce microbial dysbiosis. Both conditions were induced either alone or in combination at defined time points. Using IL-4 reporter mice, we found that TS as well as the combination of TS and S. aureus increased the appearance of IL-4-producing cell types such as T helper type 2 cells, basophils and natural killer T cells in the skin, accompanied by increased mRNA expression of IL-13, IL-4, CCL17 and CCL22, 6 days after treatment. Skin-draining lymph nodes mimicked the previously described dynamics of IL-4- producing cell types. Moreover, increased mRNA expression of IL-33, CXCL1 and IL-6 was detected at early time points, accompanied by downregulation of skin barrier-forming proteins within the combined treatment with TS and S. aureus. Analyses of the skin microbiome of WT mice affirm this finding by pointing to a shift within the microbial homeostasis characterized by a predominance of Staphylococci after TS. This shows that skin barrier impairment and microbial dysbiosis act synergistically to induce the increased appearance of specific IL-4-producing cell types, as well as other features of AD. In the long term, this project will clarify the role of different type 2 cytokine- producing cells in the development of AD beyond Th2 cells and develop new treatment strategies.

Mesenchymal stem cells derived from human dental follicle modulate the aberrant immune response in atopic dermatitis.

Background: Atopic dermatitis (AD) is an inflammatory cutaneous disorder. The advancements in the understanding of AD immunological pathogenesis have caused the development of therapies that suppress the dysregulated immune response. We aimed to evaluate the immunomodulatory effect of dental stem cells (dental follicle-mesenchymal stem cells [DF-MSCs]) on AD patients. Materials & methods: We investigated the immunoregulatory potential of DF-MSCs on T cell response in AD and compared them with psoriasis and healthy individuals and the underlying mechanisms. Results: DF-MSCs significantly reduced Fas, FasL and TNFR II frequency in T cells, increased naive T cell population while reducing memory T cell, decreased inflammatory cytokine levels and promoted Tregs frequency in the AD population. Conclusion: These results imply that DF-MSCs are modulating inflammation through decreasing T cell apoptosis, inducing Treg expansion and stabilizing cytokine levels.

Epicutaneous Staphylococcus aureus induces IL-36 to enhance IgE production and ensuing allergic disease.

IgE induced by type 2 immune responses in atopic dermatitis is implicated in the progression of atopic dermatitis to other allergic diseases, including food allergies, allergic rhinitis, and asthma. However, the keratinocyte-derived signals that promote IgE and ensuing allergic diseases remain unclear. Herein, in a mouse model of atopic dermatitis-like skin inflammation induced by epicutaneous Staphylococcus aureus exposure, keratinocyte release of IL‑36α along with IL-4 triggered B cell IgE class-switching, plasma cell differentiation, and increased serum IgE levels-all of which were abrogated in IL-36R-deficient mice or anti-IL‑36R-blocking antibody-treated mice. Moreover, skin allergen sensitization during S. aureus epicutaneous exposure-induced IL-36 responses was required for the development of allergen-specific lung inflammation. In translating these findings, elevated IL‑36 cytokines in human atopic dermatitis skin and in IL‑36 receptor antagonist-deficiency patients coincided with increased serum IgE levels. Collectively, keratinocyte-initiated IL‑36 responses represent a key mechanism and potential therapeutic target against allergic diseases.

Keratinocytes: innate immune cells in atopic dermatitis.

The skin is a unique immune organ that constitutes a complex network of physical, chemical and microbiological barriers against external insults. Keratinocytes are the most abundant cell type in the epidermis. These cells form the physical skin barrier and represent the first line of the host defense system by sensing pathogens via innate immune receptors, initiating anti-microbial responses and producing various cytokines, chemokines and anti-microbial peptides, which are important events in immunity. A damaged epidermal barrier in atopic dermatitis allows the penetration of potential allergens and pathogens to activate keratinocytes. Among the dysregulation of immune responses in atopic dermatitis, activated keratinocytes play a role in several biological processes that contribute to the pathogenesis of atopic dermatitis. In this review, we summarize the current understanding of the innate immune functions of keratinocytes in the pathogenesis of atopic dermatitis, with a special emphasis on skin-derived anti-microbial peptides and atopic dermatitis-related cytokines and chemokines in keratinocytes. An improved understanding of the innate immunity mediated by keratinocytes can provide helpful insight into the pathophysiological processes of atopic dermatitis and support new therapeutic efforts.

Profiling transcriptomic changes and signaling pathways in atopic dermatitis by integrative analyses on multiple databases.

Atopic dermatitis (AD) is a condition driven by T cell-mediated immune response. Targeted therapy of AD is challenging due to its complex pathogenesis. In the current study, by analyzing multiple expression and network datasets, we aimed at: (1) identifying important transcriptomic signatures/profiles for AD to seek potential therapeutic targets and (2) discovering key regulators in the pathogenesis of AD. Our differentially expressed gene (DEG) analysis revealed multiple genes involved in immune response and dermal structural integrity. Functional enrichment analyses suggested that signaling pathways involved in epidermal barrier and inflammation and immunity are overrepresented in lesional AD. Protein-protein interaction (PPI) network and causal interactions analyses highlighted the roles of regulators of epidermal integrity and immune response in the pathogenesis of AD. Prominently, a negative regulator of the B-cell receptor-mediated immune response, PKCβ, has been suggested in the predicted pathogenesis model for AD, implying B cell-mediated immune response may play an equally important role as that of the T cell-mediated immune response in AD. A further search in a perturbagen database has identified small molecular drugs that may alter expression profiles of key regulators in the pathogenesis of AD. In this study, we propose a systemic multi-omics strategy incorporating multiple analyses on various datasets of transcriptomes, diseases, and pharmacology. Such integrative analyses will effectively advance our understanding on the pathogenesis and treatment of AD.

Mast cell–derived IL-13 downregulates IL-12 production by skin dendritic cells to inhibit the TH1 cell response to cutaneous antigen exposure

Atopic dermatitis (AD) is characterized by a skin barrier defect aggravated by mechanical injury inflicted by scratching, a TH2 cell-dominated immune response, and susceptibility to viral skin infections that are normally restrained by a TH1 cell response. The signals leading to a TH2 cell-dominated immune response in AD are not completely understood. Our aim was to determine the role of IL-13 in initiation of the TH cell response to cutaneously encountered antigens. Wild-type, Il13-/-, Il1rl1-/-, and Il4ra-/- mice, as well as mice with selective deficiency of IL-13 in mast cells (MCs) were studied; in addition, dendritic cells (DCs) purified from the draining lymph nodes of tape-stripped and ovalbumin (OVA)-sensitized skin were examined for their ability to polarize naive OVA-TCR transgenic CD4+ T cells. Cytokine expression was examined by reverse-transcriptase quantitative PCR, intracellular flow cytometry, and ELISA. Contact hypersensitivity to dinitrofluorobenzene was examined. Tape stripping caused IL-33-driven upregulation of Il13 expression by skin MCs. MC-derived IL-13 acted on DCs from draining lymph nodes of OVA-sensitized skin to selectively suppress their ability to polarize naive OVA-TCR transgenic CD4+ T cells into IFN-γ-secreting cells. MC-derived IL-13 inhibited the TH1 cell response in contact hypersensitivity to dinitrofluorobenzene. IL-13 suppressed IL-12 production by mouse skin-derived DCs invitro and invivo. Scratching upregulated IL13 expression in human skin, and IL-13 suppressed the capacity of LPS-stimulated human skin DCs to express IL-12 and promote IFN-γ secretion by CD4+ T cells. Release of IL-13 by cutaneous MCs in response to mechanical skin injury inhibits the TH1 cell response to cutaneous antigen exposure in AD.

Abrocitinib: a potential treatment for moderate-to-severe atopic dermatitis

ABSTRACT Introduction Atopic dermatitis (AD) is a common and debilitating dermatosis that often impacts the physical and psychological quality of life in children and adults. A limited number of treatment options are available for AD, and often these treatments result in an insufficient response or may be contraindicated for some patients. This treatment gap creates an increasing demand for alternative AD therapies. The Janus kinase (JAK)-signal transducers and activators of transcription (STAT) pathway is known to play a critical role in the dysregulation of immune responses in AD. Inhibition of the JAK enzymes in the JAK-STAT pathway has shown potential for the treatment of this chronic skin condition. Areas covered We review the evolving efficacy and safety profile of abrocitinib, an oral JAK1 inhibitor, in the treatment of AD based on the data available from phase I, II, and III clinical trials. Expert opinion Evidence supports clinical efficacy, improved pruritus and an acceptable safety profile, making abrocitinib a viable alternative to conventional AD therapies. Pivotal phase III trials included subjects aged 12 years and above, providing a new mechanism of action for future treatment of adolescent and adult AD. Further investigations are required to have a thorough understanding of abrocitinib in the treatment of AD.

What Have We Learned from GWAS for Atopic Dermatitis?

GWASs have revealed multiple loci associated with atopic dermatitis (AD). Some have confirmed pre-existing knowledge, including the role of skin barrier and type 2 inflammation in AD pathogenesis, whereas others have provided newer insights, including evidence of autoimmunity and previously unrecognized genes controlling epidermal differentiation. The majority of risk loci are in intergenic regions for which functional mechanism(s) remain unknown. These loci require detailed molecular studies carried out in cells and tissues of relevance to AD. Genomic findings to date account for ∼30% of AD heritability, therefore, considerable further work is needed to fully understand individual risk.

HY209 ameliorates atopic dermatitis through NF-KB and P38 inhibition

Abstract HY209 has been reported to be a ligand for the membrane G protein–coupled receptor, TGR5. HY209 could inhibit inflammatory responses in sepsis by increasing number of immunosuppressive myeloid-derived suppressor cells (MDSC), suggesting the potent role of HY209 in the treatment of atopic dermatitis (AD). Here HY209 was evaluated whether it controls inflammatory immune responses in AD. We employed mouse AD model using a topical treatment of dinitrochlorobenzene (DNCB) on the dorsal skin of Balb/c mice. HY209-treated mice showed significantly reduction in Th2 immune responses, shown as lower IgE serum, and inhibition of T cells mast cells, eosinophilia and neutrophil recruitment accompanied with reduced in epidermal and dermal thickness in skin of HY209 treated mice. Interestingly, regulatory T cells noticeably increased upon to HY209 treatment along with inhibition of type 2 cytokines production. Proteogenomic analyses of mouse skin demonstrated upregulated expression of molecules responsible for tissue regeneration and downregulated expression of proinflammatory molecules. Consistent with these findings, in vitro data indicated that HY209 decreased production of thymic stromal lymphopoietin (TSLP) and CCL17 (TARC) through inhibition of NF-KB and MAPK (P38) pathway. Taken together, HY209 ameliorates AD in mice by normalizing Th1/Th2 imbalance immune responses and inhibiting various pro-inflammatory responses via TGR5-cAMP-PKA axis, Suggesting HY209 could be a promising therapeutic candidate for AD.