Genome-wide comparative analysis of atopic dermatitis and psoriasis gives insight into opposing genetic mechanisms

A genome-wide association study of hand eczema identifies locus 20q13.33 and reveals genetic overlap with atopic dermatitis

BACKGROUND

Twin studies revealed that genetic effects play a role in hand eczema (HE), but the responsible genetic factors are unknown.

OBJECTIVES

To identify and characterise genetic loci associated with HE and to provide insight into the genetic overlap between HE and atopic dermatitis (AD).

METHODS

We used questionnaire-derived and genotype data from the European population-based Lifelines cohort and biobank. We performed a discovery genome-wide association study (GWAS) of HE (2879 cases and 16 249 controls) and of AD (1706 cases and 17 190 controls). We replicated our findings in an independent Lifelines sample for HE (1188 cases and 6431 controls) and AD (757 cases and 6747 controls). We conducted several post-GWAS analyses and performed genetic correlation analyses between our HE results and independent AD data.

RESULTS

The two-step GWAS of HE, regardless of adjusting for AD, identified one independent locus 20q13.33, likely driven by a number of causal single-nucleotide polymorphisms. For the AD GWAS, we replicated a known stop-gained rs61816761 at locus 1q21.3 (FLG, FLGAS1). We found a strong genetic correlation (p < 0.01) between HE and AD (rg = 0.65), regardless of adjusting for AD (rg = 0.63).

CONCLUSIONS

Locus 20q13.33 is associated with HE, and there is a large genetic overlap between HE and AD.

Tissue gene expression profiles and communication networks inform candidate blood biomarker identification in psoriasis and atopic dermatitis

Overlapping clinical and pathomechanistic features can complicate the diagnosis and treatment of inflammatory skin diseases, including psoriasis and atopic dermatitis (AD). Spatial transcriptomics allows the identification of disease- and cell-specific molecular signatures that may advance biomarker development and future treatments. This study identified transcriptional signatures in keratinocytes and sub-basal CD4+ and CD8+ T lymphocytes from patients with psoriasis and AD. In silico prediction of ligand:receptor interactions delivered key signalling pathways (interferon, effector T cells, stroma cell and matrix biology, neuronal development, etc.). Targeted validation of selected transcripts, including CCL22, RELB, and JUND, in peripheral blood T cells suggests the chosen approach as a promising tool also in other inflammatory diseases. Psoriasis and AD are characterized by transcriptional dysregulation in T cells and keratinocytes that may be targeted therapeutically. Spatial transcriptomics is a valuable tool in the search for molecular signatures that can be used as biomarkers and/or therapeutic targets.

TRPV3-Activated PARP1/AIFM1/MIF Axis through Oxidative Stress Contributes to Atopic Dermatitis

TRPV3 is a temperature-sensitive calcium-permeable channel. In previous studies, we noticed prominent TUNEL-positive keratinocytes in patients with Olmsted syndrome and Trpv3+/G568V mice, both of which carry gain-of-function variants in the TRPV3 gene. However, it remains unclear how the keratinocytes die and whether this process contributes to more skin disorders. In this study, we showed that gain-of-function variant or pharmacological activation of TRPV3 resulted in poly(ADP-ribose) polymerase 1 (PARP1)/AIFM1/macrophage migration inhibitory factor axis-mediated parthanatos, which is an underestimated form of cell death in skin diseases. Chelating calcium, scavenging ROS, or inhibiting nitric oxide synthase effectively rescued the parthanatos, indicating that TRPV3 regulates parthanatos through calcium-mediated oxidative stress. Furthermore, inhibiting PARP1 downregulated TSLP and IL33 induced by TRPV3 activation in HaCaT cells, reduced immune cell infiltration, and ameliorated epidermal thickening in Trpv3+/G568V mice. Marked parthanatos was also detected in the skin of MC903-treated mice and patients with atopic dermatitis, whereas inhibiting PARP1 largely alleviated the MC903-induced dermatitis. In addition, stimulating parthanatos in mouse skin with methylnitronitrosoguanidine recapitulated many features of atopic dermatitis. These data demonstrate that the TRPV3-regulated parthanatos-associated PARP1/AIFM1/macrophage migration inhibitory factor axis is a critical contributor to the pathogenesis of Olmsted syndrome and atopic dermatitis, suggesting that modulating the PARP1/AIFM1/macrophage migration inhibitory factor axis is a promising therapy for these conditions.

Genetic and Immunological Pathogenesis of Atopic Dermatitis

Type 2 immune-mediated diseases give a clear answer to the issue of nature (genetics) versus nurture (environment). Both genetics and environment play vital complementary roles in the development of atopic dermatitis (AD). As a key component of the atopic march, AD demonstrates the interactive nature of genetic and environmental contributions to atopy. From sequence variants in the epithelial barrier gene encoding FLG to the hygiene hypothesis, AD combines a broad array of contributions into a single syndrome. This review will focus on the genetic contribution to AD and where genetics facilitates the elicitation or enhancement of AD pathogenesis.

Application of JAK inhibitors in paradoxical reaction through immune-related dermatoses

Biologics play a positive and effective role in the treatment of immune-related dermatoses. However, many other immune-related diseases have also manifested along with biologics treatment. Paradoxical reaction through immune-related dermatoses refer to the new onset or exacerbation of other immune-mediated dermatoses (mainly psoriasis and atopic dermatitis) after biologics treatment of inflammatory dermatoses (mainly psoriasis and atopic dermatitis), such as new atopic dermatitis (AD) in psoriasis (PsO) treatment and new PsO in AD treatment. A common genetic background and Inflammatory pathway are possible pathogenesis. Faced with paradoxical reactions, the choice of therapy needs to be directed toward therapies effective for both diseases, such as Janus kinase (JAK) inhibitors. The Janus kinase and signal transducer and activator of transcription (JAK-STAT) pathway plays an important role in the inflammatory pathway, and has been widely used in the treatment of AD and PsO in recent years. This article focuses on JAK inhibitors such as tofacitinib, baricitinib, ruxolitinib, Abrocitinib, upadacitinib, and deucravacitinib, to explore the possible application in treatment of paradoxical reactions. Common side effects, baseline risk factors and safety use of JAK inhibitors were discussed.

Cross-Comparison of Inflammatory Skin Disease Transcriptomics Identifies PTEN as a Pathogenic Disease Classifier in Cutaneous Lupus Erythematosus

Tissue transcriptomics is used to uncover molecular dysregulations underlying diseases. However, the majority of transcriptomics studies focus on single diseases with limited relevance for understanding the molecular relationship between diseases or for identifying disease-specific markers. In this study, we used a normalization approach to compare gene expression across nine inflammatory skin diseases. The normalized datasets were found to retain differential expression signals that allowed unsupervised disease clustering and identification of disease-specific gene signatures. Using the NS-Forest algorithm, we identified a minimal set of biomarkers and validated their use as diagnostic disease classifier. Among them, PTEN was identified as being a specific marker for cutaneous lupus erythematosus and found to be strongly expressed by lesional keratinocytes in association with pathogenic type I IFNs. In fact, PTEN facilitated the expression of IFN-β and IFN-κ in keratinocytes by promoting activation and nuclear translocation of IRF3. Thus, cross-comparison of tissue transcriptomics is a valid strategy to establish a molecular disease classification and to identify pathogenic disease biomarkers.

Risk of Paradoxical Eczema in Patients Receiving Biologics for Psoriasis

Importance

Biologics used for plaque psoriasis have been reported to be associated with an atopic dermatitis (AD) phenotype, or paradoxical eczema, in some patients. The risk factors for this are unknown.

Objective

To explore risk of paradoxical eczema by biologic class and identify factors associated with paradoxical eczema.

Design, Setting, and Participants

This prospective cohort study used data from the British Association of Dermatologists Biologics and Immunomodulators Register for adults treated with biologics for plaque psoriasis who were seen at multicenter dermatology clinics in the UK and Ireland. Included participants were registered and had 1 or more follow-up visits between September 2007 and December 2022.

Exposures

Duration of exposure to tumor necrosis factor (TNF) inhibitors, interleukin (IL) 17 inhibitors, IL-12/23 inhibitors, or IL-23 inhibitors until paradoxical eczema onset, treatment discontinuation, last follow-up, or death.

Main Outcomes and Measures

Incidence rates of paradoxical eczema, paradoxical eczema risk by biologic class, and the association of demographic and clinical variables with risk of paradoxical eczema were assessed using propensity score-weighted Cox proportional hazards regression models.

Results

Of 56 553 drug exposures considered, 24 997 from 13 699 participants were included. The 24 997 included exposures (median age, 46 years [IQR, 36-55 years]; 57% male) accrued a total exposure time of 81 441 patient-years. A total of 273 exposures (1%) were associated with paradoxical eczema. The adjusted incidence rates were 1.22 per 100 000 person-years for IL-17 inhibitors, 0.94 per 100 000 person-years for TNF inhibitors, 0.80 per 100 000 person-years for IL-12/23 inhibitors, and 0.56 per 100 000 person-years for IL-23 inhibitors. Compared with TNF inhibitors, IL-23 inhibitors were associated with a lower risk of paradoxical eczema (hazard ratio [HR], 0.39; 95% CI, 0.19-0.81), and there was no association of IL-17 inhibitors (HR, 1.03; 95% CI, 0.74-1.42) or IL-12/23 inhibitors (HR, 0.87; 95% CI, 0.66-1.16) with risk of paradoxical eczema. Increasing age (HR, 1.02 per year; 95% CI, 1.01-1.03) and history of AD (HR, 12.40; 95% CI, 6.97-22.06) or hay fever (HR, 3.78; 95% CI, 1.49-9.53) were associated with higher risk of paradoxical eczema. There was a lower risk in males (HR, 0.60; 95% CI, 0.45-0.78).

Conclusions and Relevance

In this study, in biologic-treated patients with psoriasis, paradoxical eczema risk was lowest in patients receiving IL-23 inhibitors. Increasing age, female sex, and history of AD or hay fever were associated with higher risk of paradoxical eczema. The overall incidence of paradoxical eczema was low. Further study is needed to replicate these findings.

Development of a clinical algorithm to predict phenotypic switches between atopic dermatitis and psoriasis (the "Flip-Flop" phenomenon)

BACKGROUND

Atopic dermatitis (AD) and psoriasis vulgaris (PV) are almost mutually exclusive diseases with different immune polarizations, mechanisms and therapeutic targets. Switches to the other disease ("Flip-Flop" [FF] phenomenon) can occur with or without systemic treatment and are often referred to as paradoxical reactions under biological therapy.

METHODS

The objective was to develop a diagnostic algorithm by combining clinical criteria of AD and PV to identify FF patients. The algorithm was prospectively validated in patients enrolled in the CK-CARE registry in Bonn, Germany. Afterward, algorithm refinements were implemented based on machine learning.

RESULTS

Three hundred adult Caucasian patients were included in the validation study (n = 238 with AD, n = 49 with PV, n = 13 with FF; mean age 41.2 years; n = 161 [53.7%] female). The total FF scores of the PV and AD groups differed significantly from the FF group in the validation data (p < .001). The predictive mean generalized Youden-Index of the initial model was 78.9% [95% confidence interval 72.0%-85.6%] and the accuracy was 89.7%. Disease group-specific sensitivity was 100% (FF), 95.0% (AD), and 61.2% (PV). The specificity was 89.2% (FF), 100% (AD), and 100% (PV), respectively.

CONCLUSION

The FF algorithm represents the first validated tool to identify FF patients.

Integrated proteomics and genomics analysis of paradoxical eczema in psoriasis patients treated with biologics

BACKGROUND

Few studies have explored the immunology and genetic risk of paradoxical eczema occurring as an adverse event of biologic therapy in patients with psoriasis.

OBJECTIVES

We sought to describe the systemic inflammatory signature of paradoxical eczema using proteomics and explore whether this is genetically mediated.

METHODS

This study used the Olink Target 96 Inflammation panel on 256 serum samples from 71 patients with psoriasis and paradoxical eczema, and 75 controls with psoriasis to identify differentially expressed proteins and enriched gene sets. Case samples from 1 or more time points (T1 prebiologic, T2 postbiologic, and T3 postparadoxical eczema) were matched 1:1 with control samples. Genes contributing to enriched gene sets were selected, and functional single nucleotide polymorphisms used to create polygenic risk scores in a genotyped cohort of 88 paradoxical eczema cases and 3124 psoriasis controls.

RESULTS

STAMBP expression was lower in cases at T1 than in controls (log-fold change: -0.44; adjusted P = .022); no other proteins reached statistical significance at equivalent time points. Eleven gene sets including cytokine and chemokine pathways were enriched in cases at T2 and 10 at T3. Of the 39 proteins contributing to enriched gene sets, the majority are associated with the atopic dermatitis serum proteome. A polygenic risk score including 38 functional single nucleotide polymorphisms linked to enriched gene sets was associated with paradoxical eczema (adjusted P = .046).

CONCLUSIONS

The paradoxical eczema systemic inflammatory proteome trends toward atopic dermatitis at a gene-set level and is detectable before onset of the phenotype. This signature could be genetically determined.

Multi-modal skin atlas identifies a multicellular immune-stromal community associated with altered cornification and specific T cell expansion in atopic dermatitis

In healthy skin, a cutaneous immune system maintains the balance between tolerance towards innocuous environmental antigens and immune responses against pathological agents. In atopic dermatitis (AD), barrier and immune dysfunction result in chronic tissue inflammation. Our understanding of the skin tissue ecosystem in AD remains incomplete with regard to the hallmarks of pathological barrier formation, and cellular state and clonal composition of disease-promoting cells. Here, we generated a multi-modal cell census of 310,691 cells spanning 86 cell subsets from whole skin tissue of 19 adult individuals, including non-lesional and lesional skin from 11 AD patients, and integrated it with 396,321 cells from four studies into a comprehensive human skin cell atlas in health and disease. Reconstruction of human keratinocyte differentiation from basal to cornified layers revealed a disrupted cornification trajectory in AD. This disrupted epithelial differentiation was associated with signals from a unique immune and stromal multicellular community comprised of MMP12 + dendritic cells (DCs), mature migratory DCs, cycling ILCs, NK cells, inflammatory CCL19 + IL4I1 + fibroblasts, and clonally expanded IL13 + IL22 + IL26 + T cells with overlapping type 2 and type 17 characteristics. Cell subsets within this immune and stromal multicellular community were connected by multiple inter-cellular positive feedback loops predicted to impact community assembly and maintenance. AD GWAS gene expression was enriched both in disrupted cornified keratinocytes and in cell subsets from the lesional immune and stromal multicellular community including IL13 + IL22 + IL26 + T cells and ILCs, suggesting that epithelial or immune dysfunction in the context of the observed cellular communication network can initiate and then converge towards AD. Our work highlights specific, disease-associated cell subsets and interactions as potential targets in progression and resolution of chronic inflammation.

Immunosuppression causes dynamic changes in expression QTLs in psoriatic skin

Psoriasis is a chronic, systemic inflammatory condition primarily affecting skin. While the role of the immune compartment (e.g., T cells) is well established, the changes in the skin compartment are more poorly understood. Using longitudinal skin biopsies (n = 375) from the "Psoriasis Treatment with Abatacept and Ustekinumab: A Study of Efficacy"(PAUSE) clinical trial (n = 101), we report 953 expression quantitative trait loci (eQTLs). Of those, 116 eQTLs have effect sizes that were modulated by local skin inflammation (eQTL interactions). By examining these eQTL genes (eGenes), we find that most are expressed in the skin tissue compartment, and a subset overlap with the NRF2 pathway. Indeed, the strongest eQTL interaction signal - rs1491377616-LCE3C - links a psoriasis risk locus with a gene specifically expressed in the epidermis. This eQTL study highlights the potential to use biospecimens from clinical trials to discover in vivo eQTL interactions with therapeutically relevant environmental variables.

Atopic Polygenic Risk Score Is Associated with Paradoxical Eczema Developing in Patients with Psoriasis Treated with Biologics

Biologic therapies for psoriasis can cause paradoxical eczema. The role of genetic factors in its pathogenesis is unknown. To identify risk variants, we conducted a GWAS of 3,212 patients with psoriasis, of whom 88 developed paradoxical eczema. Two lead SNPs reached genome-wide significance (P ≤ 5 × 10-8) for association with paradoxical eczema: rs192705221 (near UNC5B, P = 9.52 × 10-10) and rs72925168 (within SLC1A2, P = 1.66 × 10-9). Genome-wide significant SNPs from published GWAS were used to generate polygenic risk scores (PRSs) for atopic eczema, general atopic disease, or a combination, which were tested for association with paradoxical eczema. Improvement over a clinical risk model was assessed by the area under the curve. All three atopy polygenic risk scores were associated with paradoxical eczema (P < 0.05); polygenic risk score for a combination of atopic eczema and general atopic disease had the strongest association (OR = 1.83, 95% CI = 1.17-2.84, P = 0.0078). Including atopic polygenic risk scores in the multivariable model, which included age, sex, atopic background, and psoriatic arthritis history, increased the area under the curve from 0.671 to 0.681-0.686. Atopic genetic burden is associated with paradoxical eczema occurring in biologic-treated patients with psoriasis, indicating shared underlying mechanisms. Incorporating genetic risk may improve treatment outcome prediction models for psoriasis.

Intrinsic Effects of Exposome in Atopic Dermatitis: Genomics, Epigenomics and Regulatory Layers

Atopic dermatitis (AD) or atopic eczema is an increasingly manifested inflammatory skin disorder of complex etiology which is modulated by both extrinsic and intrinsic factors. The exposome includes a person's lifetime exposures and their effects. We recently reviewed the extrinsic exposome's environmental risk factors that contribute to AD. The periods of pregnancy, infancy, and teenage years are recognized as crucial stages in the formation of AD, where the exposome leads to enduring impacts on the immune system. However, research is now focusing on the interactions between intrinsic pathways that are modulated by the extrinsic exposome, including genetic variation, epigenetic modifications, and signals, such as diet, stress, and microbiome interactions. As a result, immune dysregulation, barrier dysfunction, hormonal fluctuations, and skin microbiome dysbiosis are important factors contributing to AD development, and their in-depth understanding is crucial not only for AD treatment but also for similar inflammatory disorders.

Pathogen-specific innate immune response patterns are distinctly affected by genetic diversity

Innate immune responses vary by pathogen and host genetics. We analyze quantitative trait loci (eQTLs) and transcriptomes of monocytes from 215 individuals stimulated by fungal, Gram-negative or Gram-positive bacterial pathogens. We identify conserved monocyte responses to bacterial pathogens and a distinct antifungal response. These include 745 response eQTLs (reQTLs) and corresponding genes with pathogen-specific effects, which we find first in samples of male donors and subsequently confirm for selected reQTLs in females. reQTLs affect predominantly upregulated genes that regulate immune response via e.g., NOD-like, C-type lectin, Toll-like and complement receptor-signaling pathways. Hence, reQTLs provide a functional explanation for individual differences in innate response patterns. Our identified reQTLs are also associated with cancer, autoimmunity, inflammatory and infectious diseases as shown by external genome-wide association studies. Thus, reQTLs help to explain interindividual variation in immune response to infection and provide candidate genes for variants associated with a range of diseases.

Dupilumab-Associated Psoriasis and Psoriasiform Manifestations: A Scoping Review

BACKGROUND

Dupilumab is the first approved IL-4Rα inhibitor for the treatment of atopic dermatitis at present with good efficacy and safety. However, there have been several reports of psoriasis and psoriasiform manifestations occurring after dupilumab therapy in recent years, showing a new paradoxical cutaneous reaction associated with biologics.

SUMMARY

This is a scoping review in order to summarize the demographics and epidemiology, clinical manifestations, diagnosis, potential pathogenesis, and promising management of dupilumab-associated psoriasis and psoriasiform manifestations.

Exploring the relationship between socioeconomic deprivation index and Alzheimer's disease using summary-level data: From genetic correlation to causality

Patients with Alzheimer's disease (AD) are markedly increasing as population aging and no disease-modifying therapies are currently available for AD. Previous studies suggested a broad link between socioeconomic status and a variety of disorders, including mental illness and cognitive abilities. However, the association between socioeconomic deprivation and AD has been unknown. We here employed Townsend deprivation index (TDI) to explore such relation and found a positive genetic correlation (r̂_g=0.211, P = 8.00 × 10^-4) between the two traits with summary statistics data (N = 455,258 for TDI and N = 455,815 for AD). Then, we performed pleiotropy analysis at both variant and gene levels using a powerful method called PLACO and detected 87 distinct pleiotropic genes. Functional analysis demonstrated these genes were significantly enriched in pancreas, liver, heart, blood, brain, and muscle tissues. Using Mendelian randomization methods, we further found that one genetically predicted standard deviation elevation in TDI could lead to approximately 18.5% (95% confidence intervals 1.6- 38.2%, P = 0.031) increase of AD risk, and that the identified causal association was robust against used MR approaches, horizontal pleiotropy, and instrumental selection. Overall, this study provides deep insight into common genetic components underlying TDI and AD, and further reveals causal connection between them. It is also helpful to develop a more suitable plan for ameliorating inequities, hardship, and disadvantage, with the hope of improving health outcomes among economically disadvantaged people.

New insights from genetic studies of eczema

Genome-wide association studies (GWAS) provided fundamental insight into the genetic determinants of complex allergic diseases. For eczema, 58 susceptibility loci were reported. Protein-changing variants were associated with eczema at genome-wide significance at 12 loci. The majority of risk variants were, however, located in non-coding, regulatory regions of the genome. Prioritized target genes were enriched in pathways of the immune response and of epithelial barrier function. Interestingly, a large overlap in the genetic architecture underlying different allergic diseases was identified pointing to common pathomechanisms for eczema, asthma, hay fever, and food allergy. Here, we review the most recent findings from GWAS for eczema including the role of rare variants and genetic heterogeneity in ethnically diverse populations. In addition, we provide an overview of genes underlying Mendelian disorders featuring eczematous skin inflammation.

Genetic correlation and gene-based pleiotropy analysis for four major neurodegenerative diseases with summary statistics

Recent genome-wide association studies suggested shared genetic components between neurodegenerative diseases. However, pleiotropic association patterns among them remain poorly understood. We here analyzed 4 major neurodegenerative diseases including Alzheimer's disease (AD), Parkinson's disease (PD), frontotemporal dementia (FTD) and amyotrophic lateral sclerosis (ALS), and found suggestively positive genetic correlation. We next implemented a gene-centric pleiotropy analysis with a powerful method called PLACO and detected 280 pleiotropic associations (226 unique genes) with these diseases. Functional analyses demonstrated that these genes were enriched in the pancreas, liver, heart, blood, brain, and muscle tissues; and that 42 pleiotropic genes exhibited drug-gene interactions with 341 drugs. Using Mendelian randomization, we discovered that AD and PD can increase the risk of developing ALS, and that AD and ALS can also increase the risk of developing FTD, respectively. Overall, this study provides in-depth insights into shared genetic components and causal relationship among the 4 major neurodegenerative diseases, indicating genetic overlap and causality commonly drive their co-occurrence. It also has important implications on the etiology understanding, drug development and therapeutic targets for neurodegenerative diseases.

Biologics-Induced Immunophenotypic Cross-Switching in Patients with Psoriasis and Atopic Dermatitis

Antibody-based therapies that inhibit pro-inflammatory cytokine signalling are commonly used in dermatology. Paradoxically, these biological agents may induce or exacerbate paradoxical reactions. Recently, it has been reported that the treatment of eczema with dupilumab can lead to the development of psoriasiform eruptions, which we called psoriasiform paradoxical reactions (P-PRs). Conversely, cases of eczematous paradoxical reactions (E-PRs) have also been described in patients with psoriasis treated with biologics. To summarise the case characteristics and disease features of phenotypic transition between psoriasis and eczematoid dermatitis, and to explore the mechanism or connection related to biological agents or patients' genetic characteristics, a systematic review was conducted for P-PRs in atopic dermatitis and E-PRs in patients with psoriasis treated with corresponding biological agents, respectively. We identified a series of P-PRs in 42 atopic dermatitis cases treated with dupilumab. The time to onset of P-PRs typically ranged from weeks to months, with a mean latency period of 22.65 weeks. Almost all patients presented with new-onset P-PRs. Simultaneously, we reviewed 22 articles reporting 51 patients with psoriasis with biological agent-induced E-PRs, which occurred on average at 24.47 weeks, 72.55% of them induced by IL-17A inhibitors. 48.98% (24/49) of cases reported a positive personal history of atopy, which may suggest an increased risk of biological agent-induced paradoxical eruptions. Overall, the improvement or resolution upon discontinuation of the inciting biologics was relatively common, and further studies are needed to estimate the real prevalence and unveil the pathophysiological mechanisms of these paradoxical events.

Multitrait genome-wide analyses identify new susceptibility loci and candidate drugs to primary sclerosing cholangitis

Primary sclerosing cholangitis (PSC) is a rare autoimmune bile duct disease that is strongly associated with immune-mediated disorders. In this study, we implemented multitrait joint analyses to genome-wide association summary statistics of PSC and numerous clinical and epidemiological traits to estimate the genetic contribution of each trait and genetic correlations between traits and to identify new lead PSC risk-associated loci. We identified seven new loci that have not been previously reported and one new independent lead variant in the previously reported locus. Functional annotation and fine-mapping nominated several potential susceptibility genes such as MANBA and IRF5. Network-based in silico drug efficacy screening provided candidate agents for further study of pharmacological effect in PSC.

Prenatal Maternal Risk Factors Contributing to Atopic Dermatitis: A Systematic Review and Meta-Analysis of Cohort Studies

BACKGROUND

The gestational risk factors predispose to the manifestation of early childhood atopic dermatitis (AD).

OBJECTIVE

We evaluated the association between modifiable and non-modifiable gestational and prenatal risk factors that affect the AD prevalence in children.

METHODS

We performed the systematic review and meta-analysis of cohort studies (n=27) in PubMed and EMBASE (2000~2021). A meta-analysis was performed using random-effects models to estimate pooled odds ratios (OR) or hazard ratio (HR). We performed a systematic review according to Preferred Reporting Item for Systematic Review and Meta-Analyses (PRISMA) guidelines and summarized cohort studies investigating gestational and prenatal risk factor those predispose to AD in off spring. Leading modifiable and non-modifiable were identified through ORs. Meta-analysis using the random effect model was also conducted to provide an overall estimate for several significant factors.

RESULTS

Among the non-modifiable risk factors gestational diabetes (7.2, 95% confidence interval [CI]: 1.4~34.5), maternal history of allergy (2.14, 95% CI: 1.54~2.97) and prenatal history of eczema (2.46, 95% CI: 1.0~5.8) were found as major determining risk factors in early manifestation of AD in children. Further, maternal exposure to industrial products (1.89, 95% CI: 1.10~3.16), exposure to antibiotics during pregnancy (3.59, 95% CI: 1.19~10.85) and passive smoking during pregnancy (2.60, 95% CI: 1.11~6.1) are leading causes of early AD manifestation.

CONCLUSION

Conclusively, both genetic and environmental factors play a pivotal role in early manifestation of AD. The better managing the environmental factors during gestational phase to the least can help curtail the prevalence of AD in children.

Advances in Current Drugs and Formulations for the Management of Atopic Dermatitis

Atopic dermatitis (AD) is a chronic, relapsing inflammatory skin disease with a complex pathophysiology. Treatment of AD remains challenging owing to the presence of a wide spectrum of clinical phenotypes and limited response to existing therapies. However, recent genetic, immunological, and pathophysiological insights into the disease mechanism resulted in the invention of novel therapeutic drug candidates. This review provides a comprehensive overview of current therapies and assesses various novel drug delivery strategies currently under clinical investigation. Further, this review majorly emphasizes on various topical treatments including emollient therapies, barrier repair agents, topical corticosteroids (TCS), phosphodiesterase 4 (PDE4) inhibitors, calcineurin inhibitors, and Janus kinase (JAK)-signal transducer and activator of transcription (STAT) pathway inhibitors. It also discusses biological and systemic therapies, upcoming treatments based on ongoing clinical trials. Additionally, this review scrutinized the use of pharmaceutical inactive ingredients in the approved topical dosage forms for AD treatment.

The Impact of Psoriasis and Atopic Dermatitis on Quality of Life: A Literature Research on Biomarkers

Psoriasis (PSO) and Atopic dermatitis (AD) are common inflammatory skin diseases that affect people of all ages globally. They negatively impact the quality of life (QoL) of patients in health-related aspects such as physical, psychological and mental functioning. Here, we conducted a review of studies relating to candidate biomarkers and indicators associated with QoL impairment in PSO and AD. Data research was performed using PUBMED and SCOPUS databases from inception to September 2022. Most of the included studies reported genomic or proteomic biomarkers associated with disease activity and QoL outcomes. Sociodemographic, clinical and therapeutic factors have also been implicated in deterioration of life quality in these patients. The inclusion of clinical characteristics, QoL impairment and co-diagnosis should be considered in drug development programs, since processing biomarkers based on an increased number of features in addition to drug class and disease will intensify the value of the biomarker itself, thereby maximizing the future clinical utility as a stratification tool.

Genetic/Environmental Contributions and Immune Dysregulation in Children with Atopic Dermatitis

Atopic dermatitis (AD) is one of the most common skin conditions in humans. AD affects up to 20% of children worldwide and results in morbidity for both patients and their caregivers. The basis of AD is an interplay between genetics and the environment characterized by immune dysregulation. A myriad of mutations that compromise the skin barrier and/or immune function have been linked to AD. Of these, filaggrin gene (FLG) mutations are the most evidenced. Many other mutations have been implicated in isolated studies that are often unreplicated, creating an archive of genes with potential but unconfirmed relevance to AD. Harnessing big data, polygenic risk scores (PRSs) and genome-wide association studies (GWAS) may provide a more practical strategy for identifying the genetic signatures of AD. Epigenetics may also play a role. Staphylococcus aureus is the most evidenced microbial contributor to AD. Cutaneous dysbiosis may result in over-colonization by pathogenic strains and aberrant skin immunity and inflammation. Aeroallergens, air pollution, and climate are other key environmental contributors to AD. The right climate and/or commensals may improve AD for some patients.

Psoriasis and cardiovascular disease risk in European and East Asian populations: evidence from meta-analysis and Mendelian randomization analysis

BACKGROUND

Psoriasis has been linked to cardiovascular disease (CVD), including coronary artery disease (CAD), myocardial infarction (MI), and heart failure (HF). However, available studies regarding this relationship have shown inconsistent results. Therefore, in this report, we performed a comprehensive review of the literature to assess the effects of psoriasis on risk of these CVDs.

METHODS

A search of literature until 24 December 2021 was done in PubMed, the Cochrane Library, Web of Science, Google Scholar, and Embase. Within European and East Asian populations, meta-analyses of observational studies assessing correlations between psoriasis and various CVD risk factors were conducted. Mendelian randomization (MR) was then employed to assess the causative impact of genetic pre-disposition for psoriasis on these CVD risk factors.

RESULTS

The results of the meta-analyses indicated that, in both the European and East Asian populations, psoriasis was significantly linked to an elevated risk in the incidence of CAD (RR = 1.51, 95% confidence interval (CI): 1.04-2.18, p = 0.028 and RR = 1.91, 95% CI: 1.62-2.25, p < 0.001) and MI (RR = 1.23, 95% CI: 1.04-1.46, p = 0.017 and RR = 2.17, 95% CI: 1.44-3.28, p < 0.001). A positive genetic relationship of psoriasis with CAD was found in European individuals (IVW OR:1.03; 95% CI: 1.01-1.06, p = 0.005) and in East Asian individuals (IVW OR:1.18; 95% CI: 1.03-1.32, p = 0.031). We also established that psoriasis was causally linked with an elevated risk of MI (IVW OR:1.05; 95% CI: 1.01-1.09, p = 0.026) in the European population as determined using an MR approach. Moreover, our MR results were congruent with the null findings from the meta-analysis assessing associations of psoriasis with HF risk.

CONCLUSIONS

This research work provides preliminary evidence that psoriasis and CVD have a common genetic origin and that targeted psoriasis treatment might improve cardiovascular outcomes. These results not only increase our knowledge of the genetic underpinnings linking a comorbidity of psoriasis with CVD but also suggests a novel approach for CVD prevention.

Elevation of IgE in patients with psoriasis: Is it a paradoxical phenomenon?

Immunoglobulin E (IgE) elevation is a hallmark of allergic conditions such as atopic dermatitis (AD). The pathogenesis of AD is typically associated with high levels of IL-4 and IL-13 produced by activated T helper 2 (Th2) cells. Psoriasis, on the other hand, is an inflammatory skin disease mainly driven by Th17 cells and their related cytokines. Although the immunopathologic reactions and clinical manifestations are often easily distinguished in the two skin conditions, patients with psoriasis may sometimes exhibit AD-like manifestations, such as elevated IgE and persistent pruritic lesions. Given the fact that the effective T cells have great plasticity to re-differentiate in response to innate and environmental factors, this unusual skin condition could be a consequence of a cross-reaction between distinct arms of T-cell and humoral immunity. Here we review the literature concerning the roles of IgE in the development of AD and psoriasis, showing that elevated IgE seems to be an important indicator for this non-typical psoriasis.

Pleiotropic modifiers of age-related diabetes and neonatal intestinal obstruction in cystic fibrosis

Individuals with cystic fibrosis (CF) develop complications of the gastrointestinal tract influenced by genetic variants outside of CFTR. Cystic fibrosis-related diabetes (CFRD) is a distinct form of diabetes with a variable age of onset that occurs frequently in individuals with CF, while meconium ileus (MI) is a severe neonatal intestinal obstruction affecting ∼20% of newborns with CF. CFRD and MI are slightly correlated traits with previous evidence of overlap in their genetic architectures. To better understand the genetic commonality between CFRD and MI, we used whole-genome-sequencing data from the CF Genome Project to perform genome-wide association. These analyses revealed variants at 11 loci (6 not previously identified) that associated with MI and at 12 loci (5 not previously identified) that associated with CFRD. Of these, variants at SLC26A9, CEBPB, and PRSS1 associated with both traits; variants at SLC26A9 and CEBPB increased risk for both traits, while variants at PRSS1, the higher-risk alleles for CFRD, conferred lower risk for MI. Furthermore, common and rare variants within the SLC26A9 locus associated with MI only or CFRD only. As expected, different loci modify risk of CFRD and MI; however, a subset exhibit pleiotropic effects indicating etiologic and mechanistic overlap between these two otherwise distinct complications of CF.

T-cell receptor sequencing specifies psoriasis as a systemic and atopic dermatitis as a skin-focused, allergen-driven disease

BACKGROUND

Atopic dermatitis (AD) and psoriasis represent two of the most common inflammatory skin diseases in developed countries. A hallmark of both diseases is T-cell infiltration into the skin. However, it is still not clarified to what extent these infiltrating T cells are antigen-specific skin-homing T cells or unspecific heterogeneous bystander cells.

METHODS

To elucidate this, T cells from lesional skin and from blood of 9 AD and 10 psoriasis patients were compared by receptor (TCR) sequencing. Therefore, peripheral blood mononuclear cells (PBMC) were cell-sorted according to expression of the cutaneous leukocyte antigen (CLA) into skin-homing (CLA⁺ ) and non-skin-homing (CLA^- ) subfractions. Aeroallergen-specific T-cell lines were grown from AD patients' PBMC in parallel.

RESULTS

Intra-individual comparison of TCRB CDR3 regions revealed that clonally expanded T cells in skin lesions of both AD and psoriasis patients corresponded to skin-homing circulating T cells. However, in psoriasis patients, these T-cell clones were also detectable to a larger extent among CLA^- circulating T cells. Up to 28% of infiltrating cells in AD skin were identified as allergen-specific by overlapping TCR sequences.

CONCLUSIONS

Our data show that in line with the systemic nature of psoriasis, T-cell clones that infiltrate psoriatic skin lesions do not exclusively possess skin-homing ability and are therefore most probably specific to antigens that are not exclusively expressed or located in the skin. T cells driving AD skin inflammation appear to home nearly exclusively to the skin and are, to a certain extent, specific to aeroallergens.

IL-13 in dermal type-2 dendritic cell specialization: from function to therapeutic targeting

Skin functions as a barrier protecting the host against physical, thermal, chemical changes and microbial insults. The skin is populated by several immune cell types which are crucial to host defence and to maintain self-tolerance as well as equilibrium with beneficial microbiota. Conventional dendritic cells (cDCs) are antigen-presenting cells that patrol the skin and all other non-lymphoid tissues for self or foreign antigens, then migrate to draining lymph nodes to initiate T cell responses. This review article describes recent developments on skin cDC specialization, focusing on the role of IL-13, a cytokine essential to allergic immune responses that is also secreted at steady state by type-2 innate lymphoid cells in healthy skin and is required for dermal cDC differentiation. Furthermore, we contextualize how different therapeutics that block IL-13 signaling and were recently approved for the treatment of atopic dermatitis might affect cDCs in human skin. This article is protected by copyright. All rights reserved.

Break on through: The role of innate immunity and barrier defence in atopic dermatitis and psoriasis

The human skin can be affected by a multitude of diseases including inflammatory conditions such as atopic dermatitis and psoriasis. Here, we describe how skin barrier integrity and immunity become dysregulated during these two most common inflammatory skin conditions. We summarise recent advances made in the field of the skin innate immune system and its interaction with adaptive immunity. We review gene variants associated with atopic dermatitis and psoriasis that affect innate immune mechanisms and skin barrier integrity. Finally, we discuss how current and future therapies may affect innate immune responses and skin barrier integrity in a generalized or more targeted approach in order to ameliorate disease in patients.

Overlapping Features of Psoriasis and Atopic dermatitis: From Genetics to Immunopathogenesis to Phenotypes

Psoriasis (PSO) and atopic dermatitis (AD) were once considered to be mutually exclusive diseases, but gradually regarded as a spectrum of disease. Shared genetic loci of both diseases were noted in some populations, including Chinese. Shared immunopathogenesis involving Th17, Th1, Th22 cells, or even IL-13 was found in certain stages or phenotypes. This review discusses the overlapping genetic susceptibility, shared cytokines, immune-mediated comorbidities, and clinical presentations. Overlapping conditions could be classified into mainly PSO lesions with AD features or vice versa, concomitant PSO and AD, or disease transformation as a result of biologics treatment.

Exploring the association between birthweight and breast cancer using summary statistics from a perspective of genetic correlation, mediation, and causality

BACKGROUND

Previous studies demonstrated a positive relationship between birthweight and breast cancer; however, inconsistent, sometimes even controversial, observations also emerged, and the nature of such relationship remains unknown.

METHODS

Using summary statistics of birthweight and breast cancer, we assessed the fetal/maternal-specific genetic correlation between them via LDSC and prioritized fetal/maternal-specific pleiotropic genes through MAIUP. Relying on summary statistics we conducted Mendelian randomization (MR) to evaluate the fetal/maternal-specific origin of causal relationship between birthweight, age of menarche, age at menopause and breast cancer.

RESULTS

With summary statistics we identified a positive genetic correlation between fetal-specific birthweight and breast cancer (r_g = 0.123 and P = 0.013) as well as a negative but insignificant correlation between maternal-specific birthweight and breast cancer (r_g = - 0.068, P = 0.206); and detected 84 pleiotropic genes shared by fetal-specific birthweight and breast cancer, 49 shared by maternal-specific birthweight and breast cancer. We also revealed fetal-specific birthweight indirectly influenced breast cancer risk in adulthood via the path of age of menarche or age at menopause in terms of MR-based mediation analysis.

CONCLUSION

This study reveals that shared genetic foundation and causal mediation commonly drive the connection between the two traits, and that fetal/maternal-specific birthweight plays substantially distinct roles in such relationship. However, our work offers little supportive evidence for the fetal origins hypothesis of breast cancer originating in utero.

Keratinocyte EGF signaling dominates in Atopic Dermatitis lesions: a comparative RNAseq analysis

Atopic dermatitis (AD) remains a highly heterogenous disorder with a multifactorial aetiology. Whilst keratinocytes are known to play a fundamental role in AD, their contribution to the overall immune landscape in moderate‐to‐severe AD is still poorly understood. In order to design new therapeutics, further investigation is needed into common disease pathways at the molecular level. We used publicly available whole‐tissue RNAseq data (4 studies) and single‐cell RNAseq keratinocyte data to identify genes/pathways that are involved in keratinocyte responses in AD and after dupilumab treatment. Transcripts present in both keratinocytes (single‐cell) and whole‐tissue, referred to as the keratinocyte‐enriched lesional skin (KELS) genes, were analysed using functional/pathway analysis. Following statistical testing, 2049 genes (16.8%) were differentially expressed in KELS. Enrichment analyses predicted increases in not only type‐1/type‐2 immune signalling and chemoattraction, but also in EGF‐dominated growth factor signalling. We identified complex crosstalk between keratinocytes and immune cells involving a dominant EGF family signature which converges on keratinocytes with potential immunomodulatory and chemotaxis‐promoting consequences. Although keratinocytes express the IL4R, we observed no change in EGF signalling in KELS after three‐month treatment with dupilumab, indicating that this pathway is not modulated by dupilumab immunotherapy. EGF family signalling is significantly dysregulated in AD lesions but is not associated with keratinocyte proliferation. EGF signalling pathways in AD require further study.

Roles Played by Stress-Induced Pathways in Driving Ethnic Heterogeneity for Inflammatory Skin Diseases

Immune-mediated skin conditions (IMSCs) are a diverse group of autoimmune diseases associated with significant disease burden. Atopic dermatitis and psoriasis are among the most common IMSCs in the United States and have disproportionate impact on racial and ethnic minorities. African American patients are more likely to develop atopic dermatitis compared to their European American counterparts; and despite lower prevalence of psoriasis among this group, African American patients can suffer from more extensive disease involvement, significant post-inflammatory changes, and a decreased quality of life. While recent studies have been focused on understanding the heterogeneity underlying disease mechanisms and genetic factors at play, little emphasis has been put on the effect of psychosocial or psychological stress on immune pathways, and how these factors contribute to differences in clinical severity, prevalence, and treatment response across ethnic groups. In this review, we explore the heterogeneity of atopic dermatitis and psoriasis between African American and European American patients by summarizing epidemiological studies, addressing potential molecular and environmental factors, with a focus on the intersection between stress and inflammatory pathways.

Polymorphisms of the filaggrin gene are associated with atopic dermatitis in the Caucasian population of Central Russia

Association of the filaggrin (FLG) gene with atopic dermatitis (AD) in Caucasians from Central Russia was studied in the sample of 700 patients and 612 controls. In total ten SNPs of the gene (rs61816761, rs12130219, rs77199844, rs558269137, rs4363385, rs12144049, rs471144, rs6661961, rs10888499, rs3126085), their haplotypes and interlocus interactions were analyzed using logistic regression. The functional effects of the AD risk candidate loci and their proxies (136 SNPs) were evaluated by in silico analysis. All analyzed SNPs were associated with AD: two SNPs (rs3126085 and rs12144049) manifested the independent association, nine SNPs were associated within 30 haplotypes, and seven SNPs showed interlocus interaction effects within ten most significant epistatic models. Alleles A rs3126085 and C rs12144049 were associated with a higher risk of AD according to the allelic (ORs being 1.75, p_perm = 0.002 and 1.45, p_perm = 0.011 respectively), additive (ORs being 1.69, p_perm = 0.004 and 1.47, p_perm = 0.011 respectively) and dominant (ORs being 1.79, p_perm = 0.004 and 1.63, p_perm = 0.005 respectively) genetic models. Three haplotypes, GT[rs3126085-rs12144049] (OR = 0.60), GGT[rs61816761-rs3126085-rs12144049] (OR = 0.59), and AWGGT[rs12130219-rs558269137-rs61816761-rs3126085-rs12144049] (OR = 0.63) demonstrated the protective effect (p_perm = 0.001). The in silico analysis suggested that the AD risk variants and their proxies apparently produce various effects on 38 genes in various tissue/organs (including 20 genes in the skin). The biological process enrichment analyses suggest that the target AD candidate genes influence the formation of the cornified envelope, keratinization and cornification, and more than twenty other pathways related to skin development, programmed cell death, and regulation of water loss via skin.

Paradoxical eczema in psoriasis patients receiving biologics: a case series

Atopic eczema and psoriasis are chronic, inflammatory dermatoses that can significantly affect the quality of life of those affected. Although both diseases are common, they rarely occur together. Severe psoriasis can be treated with biologic therapies targeting specific cytokine pathways involved in disease pathogenesis. There are reports of paradoxical eczema developing in biologic-treated psoriasis patients, sometimes necessitating treatment discontinuation leading to poor disease control. This retrospective case series identified 36 such events occurring in 23 patients. All currently-available biologic classes were implicated. Eosinophilia (n=19) and elevated serum immunoglobulin-E (n=3) were identified in some cases. Treatment strategies included no treatment, topical corticosteroids, broad-acting systemic agents and discontinuation or switch of biologic therapy. Two patients had persistent eczema and psoriasis despite discontinuation of all biologic therapies.

Thy-1 (CD90), Integrins and Syndecan 4 are Key Regulators of Skin Wound Healing

Acute skin wound healing is a multistage process consisting of a plethora of tightly regulated signaling events in specialized cells. The Thy-1 (CD90) glycoprotein interacts with integrins and the heparan sulfate proteoglycan syndecan 4, generating a trimolecular complex that triggers bi-directional signaling to regulate diverse aspects of the wound healing process. These proteins can act either as ligands or receptors, and they are critical for the successful progression of wound healing. The expression of Thy-1, integrins, and syndecan 4 is controlled during the healing process, and the lack of expression of any of these proteins results in delayed wound healing. Here, we review and discuss the roles and regulatory events along the stages of wound healing that support the relevance of Thy-1, integrins, and syndecan 4 as crucial regulators of skin wound healing.

Sequence complementarity between human noncoding RNAs and SARS-CoV-2 genes: What are the implications for human health?

Objectives

To investigate in silico the presence of nucleotide sequence complementarity between the RNA genome of Severe Acute Respiratory Syndrome CoronaVirus-2 (SARS-CoV-2) and human non-coding (nc)RNA genes.

Methods

The FASTA sequence (NC_045512.2) of each of the 11 SARS-CoV-2 isolate Wuhan-Hu-1 genes was retrieved from NCBI.nlm.nih.gov/gene and the Ensembl.org library interrogated for any base-pair match with human ncRNA genes. SARS-CoV-2 gene-matched human ncRNAs were screened for functional activity using bioinformatic analysis. Finally, associations between identified ncRNAs and human diseases were searched in GWAS databases.

Results

A total of 252 matches were found between the nucleotide sequence of SARS-CoV-2 genes and human ncRNAs. With the exception of two small nuclear RNAs, all of them were long non-coding (lnc)RNAs expressed mainly in testis and central nervous system under physiological conditions. The percentage of alignment ranged from 91.30% to 100% with a mean nucleotide alignment length of 17.5 ± 2.4. Thirty-three (13.09%) of them contained predicted R-loop forming sequences, but none of these intersected the complementary sequences of SARS-CoV-2. However, in 31 cases matches fell on ncRNA regulatory sites, whose adjacent coding genes are mostly involved in cancer, immunological and neurological pathways. Similarly, several polymorphic variants of detected non-coding genes have been associated with neuropsychiatric and proliferative disorders.

Conclusion

This pivotal in silico study shows that SARS-CoV-2 genes have Watson-Crick nucleotide complementarity to human ncRNA sequences, potentially disrupting ncRNA epigenetic control of target genes. It remains to be elucidated whether this could result in the development of human disease in the long term.

Atopic eczema: How genetic studies can contribute to understanding this complex trait

Atopic eczema is an itchy inflammatory skin disease. This complex trait results from multiple genetic and environmental factors, but atopic eczema also shows great complexity in its heterogenous presentation, clinical signs and longitudinal trajectory, with or without co-morbid conditions. The past 50 years have produced substantial improvements in the management of atopic eczema, but many patients still suffer a burden of disease affecting personal, social and family life. Genetic research refocused interest on skin barrier function, but effective targeting of this central pathomechanism remains elusive. This Perspective highlights progress in understanding molecular mechanisms and translational opportunities for the future.

The Epidermis: Redox Governor of Health and Diseases

A functional epithelial barrier necessitates protection against dehydration, and ichthyoses are caused by defects in maintaining the permeability barrier in the stratum corneum (SC), the uppermost protective layer composed of dead cells and secretory materials from the living layer stratum granulosum (SG). We have found that loricrin (LOR) is an essential effector of cornification that occurs in the uppermost layer of SG (SG1). LOR promotes the maturation of corneocytes and extracellular adhesion structure through organizing disulfide cross-linkages, albeit being dispensable for the SC permeability barrier. This review takes psoriasis and AD as the prototype of impaired cornification. Despite exhibiting immunological traits that oppose each other, both conditions share the epidermal differentiation complex as a susceptible locus. We also review recent mechanistic insights on skin diseases, focusing on the Kelch-like erythroid cell-derived protein with the cap "n" collar homology-associated protein 1/NFE2-related factor 2 signaling pathway, as they coordinate the epidermis-intrinsic xenobiotic metabolism. Finally, we refine the theoretical framework of thiol-mediated crosstalk between keratinocytes and leukocytes in the epidermis that was put forward earlier.

Cognitive Process of Psoriasis and Its Comorbidities: From Epidemiology to Genetics

Psoriasis (PsO) is a chronic inflammatory skin disease that affects approximately 2% of the population all over the world. Comorbidities of PsO have increasingly garnered more interest in the past decades. Compared with the normal population, the incidences of comorbidities are higher among patients with PsO. In the last 20 years, researchers have focused on studying the genetic components of PsO, and genetic associations between PsO and its comorbidities were elucidated. This review provides an in-depth understanding and summarization of the connection between PsO and its comorbidities from the perspectives of epidemiology and genetics. Further understanding of PsO and its comorbidities will promote research on the pathogenesis, drug development, novel therapy methods, and personalized and precision treatment of PsO and its comorbidities.

A comprehensive gene-centric pleiotropic association analysis for 14 psychiatric disorders with GWAS summary statistics

BACKGROUND

Recent genome-wide association studies (GWASs) have revealed the polygenic nature of psychiatric disorders and discovered a few of single-nucleotide polymorphisms (SNPs) associated with multiple psychiatric disorders. However, the extent and pattern of pleiotropy among distinct psychiatric disorders remain not completely clear.

METHODS

We analyzed 14 psychiatric disorders using summary statistics available from the largest GWASs by far. We first applied the cross-trait linkage disequilibrium score regression (LDSC) to estimate genetic correlation between disorders. Then, we performed a gene-based pleiotropy analysis by first aggregating a set of SNP-level associations into a single gene-level association signal using MAGMA. From a methodological perspective, we viewed the identification of pleiotropic associations across the entire genome as a high-dimensional problem of composite null hypothesis testing and utilized a novel method called PLACO for pleiotropy mapping. We ultimately implemented functional analysis for identified pleiotropic genes and used Mendelian randomization for detecting causal association between these disorders.

RESULTS

We confirmed extensive genetic correlation among psychiatric disorders, based on which these disorders can be grouped into three diverse categories. We detected a large number of pleiotropic genes including 5884 associations and 2424 unique genes and found that differentially expressed pleiotropic genes were significantly enriched in pancreas, liver, heart, and brain, and that the biological process of these genes was remarkably enriched in regulating neurodevelopment, neurogenesis, and neuron differentiation, offering substantial evidence supporting the validity of identified pleiotropic loci. We further demonstrated that among all the identified pleiotropic genes there were 342 unique ones linked with 6353 drugs with drug-gene interaction which can be classified into distinct types including inhibitor, agonist, blocker, antagonist, and modulator. We also revealed causal associations among psychiatric disorders, indicating that genetic overlap and causality commonly drove the observed co-existence of these disorders.

CONCLUSIONS

Our study is among the first large-scale effort to characterize gene-level pleiotropy among a greatly expanded set of psychiatric disorders and provides important insight into shared genetic etiology underlying these disorders. The findings would inform psychiatric nosology, identify potential neurobiological mechanisms predisposing to specific clinical presentations, and pave the way to effective drug targets for clinical treatment.

Filaggrin gene polymorphisms are associated with atopic dermatitis in women but not in men in the Caucasian population of Central Russia

Background and purpose

This study aimed to analyze the gender-specific association of the filaggrin (FLG) gene polymorphisms with atopic dermatitis (AD) in Caucasians from the central region of Russia.

Methods

The study sample consisted of 906 female (including 474 patients with AD and 432 controls) and 406 male (such as 226 patients with AD and 180 controls) participants. Genotyping of ten polymorphisms of the FLG gene was done. The logistic regression was used to analyze the associations. A total of 125 SNPs (seven AD-associated SNPs and 118 proxy SNPs, r²≥0.8) FLG gene were used for the in silico functional annotation analysis in the females.

Results

Significant associations were identified between seven SNPs of the FLG gene (rs12130219, rs61816761, rs558269137, rs12144049, rs3126085, rs471144, rs6661961) and AD in females: rs12144049 was associated independent individually (for allele C OR = 1.71, 95%Сl 1.19–2.46, р_perm = 0.004 and OR = 1.76, 95%Сl 1.18–2.63, р_perm = 0.006 according to the additive and dominant genetic models, respectively) and seven SNPs of the FLG gene within 14 haplotypes. Haplotype GGT [rs61816761-rs3126085-rs12144049] showed the strongest association (OR = 0.55, р_perm = 0.001). No association between the analyzed SNPs and AD was determined in the male group. The subsequent bioinformatic analysis predicted the SNPs of the FLG gene that possessed epigenetic and non-synonymous effects, were involved in the control of gene expression and alternative splicing of genes that contribute to AD pathophysiology.

Conclusion

Polymorphisms of the FLG gene are associated with AD in females but not in males in the Caucasian population of Central Russia.

Homeostatic IL-13 in healthy skin directs dendritic cell differentiation to promote TH2 and inhibit TH17 cell polarization

The signals driving the adaptation of type 2 dendritic cells (DC2s) to diverse peripheral environments remain mostly undefined. We show that differentiation of CD11blo migratory DC2s-a DC2 population unique to the dermis-required IL-13 signaling dependent on the transcription factors STAT6 and KLF4, whereas DC2s in lung and small intestine were STAT6-independent. Similarly, human DC2s in skin expressed an IL-4 and IL-13 gene signature that was not found in blood, spleen and lung DCs. In mice, IL-13 was secreted homeostatically by dermal innate lymphoid cells and was independent of microbiota, TSLP or IL-33. In the absence of IL-13 signaling, dermal DC2s were stable in number but remained CD11bhi and showed defective activation in response to allergens, with diminished ability to support the development of IL-4+GATA3+ helper T cells (TH), whereas antifungal IL-17+RORγt+ TH cells were increased. Therefore, homeostatic IL-13 fosters a noninflammatory skin environment that supports allergic sensitization.

Convergent Evidence Supports TH2LCRR as a Novel Asthma Susceptibility Gene

Asthma is a common complex disease with apparent genetic predispositions, and previous genome-wide association studies suggest that rs1295686 within the IL13 (interleukin 13) gene is significantly associated with asthma. Analysis of the data provided by the 1000 Genomes Project indicated that there are additional four SNPs in nearly complete linkage disequilibrium with rs1295686 in Caucasians. However, the causal SNPs and the associated mechanism remain unclear. To investigate this issue, functional genomics approaches were utilized to analyze the functions of these SNPs. Dual-luciferase assays indicated that the functional SNP is not rs1295686 but a haplotype consisting of other three SNPs, rs1295685, rs848 and rs847. Through chromosome conformation capture, it was found that the enhancer containing the three functional SNPs interacts with the promoter of TH2LCRR (T helper type 2 locus control region associated RNA), a recently identified long non-coding RNA. RNA-seq data analysis indicated that TH2LCRR expression is significantly increased in asthma patients and is dependent on the genotype at this locus, indicating that TH2LCRR is a novel susceptibility gene for asthma and that these SNPs confer asthma risk by regulating TH2LCRR expression. By chromatin immunoprecipitation, the related transcription factors that bind in the region surrounding these three SNPs were identified, and their interactions were investigated by functional genomics approaches. Our effort identified a novel mechanism through which genetic variations at this locus could influence asthma susceptibility.

Rare variant analysis in eczema identifies exonic variants in DUSP1, NOTCH4 and SLC9A4

Previous genome-wide association studies revealed multiple common variants involved in eczema but the role of rare variants remains to be elucidated. Here, we investigate the role of rare variants in eczema susceptibility. We meta-analyze 21 study populations including 20,016 eczema cases and 380,433 controls. Rare variants are imputed with high accuracy using large population-based reference panels. We identify rare exonic variants in DUSP1, NOTCH4, and SLC9A4 to be associated with eczema. In DUSP1 and NOTCH4 missense variants are predicted to impact conserved functional domains. In addition, five novel common variants at SATB1-AS1/KCNH8, TRIB1/LINC00861, ZBTB1, TBX21/OSBPL7, and CSF2RB are discovered. While genes prioritized based on rare variants are significantly up-regulated in the skin, common variants point to immune cell function. Over 20% of the single nucleotide variant-based heritability is attributable to rare and low-frequency variants. The identified rare/low-frequency variants located in functional protein domains point to promising targets for novel therapeutic approaches to eczema.

Genetic studies of eczema to date have mostly explored common genetic variation. Here, the authors perform a large meta-analysis for common and rare variants and discover 8 loci associated with eczema. Over 20% of the heritability of the condition is attributable to rare variants.

IL-12 regulates type 3 immunity through interfollicular keratinocytes in psoriasiform inflammation

[Figure: see text].

Transcriptomic Profiling of Tape-Strips From Moderate to Severe Atopic Dermatitis Patients Treated With Dupilumab

BACKGROUND

Tape-strips are a minimally invasive approach to characterize skin biomarkers in atopic dermatitis (AD). However, they have not yet been used for tracking gene expression changes with systemic treatment.

OBJECTIVE

The aim of the study was to evaluate gene expression changes and therapeutic response biomarkers in AD patients before and after dupilumab (interleukin 4Rα antibody) treatment using tape-strips to obtain epidermal tissue for analysis.

METHODS

Lesional and nonlesional tape-stripped skin was sampled from 18 AD patients before and after dupilumab treatment and from 17 healthy subjects and analyzed by RNA-seq.

RESULTS

At baseline, we detected 6745 and 4859 differentially expressed genes between lesional and nonlesional skin versus normal, respectively, whereas 841 and 977 genes were differentially expressed after treatment, respectively (fold change >1.5 and false discovery rate <0.05). Tape-strips captured significant modulation with dupilumab in key AD immune (eg, C-C motif chemokine ligand 13 [CCL13], CCL17, CCL18) and barrier (eg, periplakin, FA2H) biomarkers. Changes in biomarkers (CCL20, interleukin 34, FABP7) were also significantly correlated with clinical disease improvements (Eczema Area and Severity Index; R > 0.5 or R < -0.4, P < 0.05).

CONCLUSIONS

This real-life study represents the first comprehensive RNA-seq molecular profiling of tape-strips from moderate to severe AD patients after dupilumab therapy. Analysis of tape strip specimens detected significant gene expression changes in key AD biomarkers with dupilumab treatment, suggesting that this approach may be useful to monitor therapeutic responses in inflammatory skin diseases.

Association of KIR Genes and MHC Class I Ligands with Atopic Dermatitis

Atopic dermatitis (AD) is a chronic illness that is associated with immune dysregulation. NK cell function has previously been associated with AD. NK cells directly interact with polymorphic HLA class I ligand variants using killer cell Ig-like receptors (KIRs). The purpose of this study was to identify potential associations between NK cell function and AD by evaluating variation in the presence of KIR genes as well as KIR gene interactions with the appropriate HLA class I KIR-specific ligands. Human DNA from the genetics of AD case-control study was used to genotype HLA class I KIR-specific ligands and the presence of KIR genes. In the full cohort, an increased risk of AD was noted for KIR2DL5 (1.51 [1.13, 2.01]), KIR2DS5 (1.72 [1.26, 2.34]), and KIR2DS1 (1.41 [1.04, 1.91]). Individuals with KIR2DS5 or KIR2DS1 and the HLA-C*C2 epitope were at an increased risk of AD (1.74 [1.21, 2.51] and 1.48 [1.04, 2.12], respectively). The HLA-B*-21T (TT) leader sequence increased the risk of AD across ethnicity. African Americans with KIR2DL2, KIR2DS1, KIR2DL5, and KIR2DS5 are more likely to have AD, and the risk increased for KIR2DS1 and KIR2DS5 in the presence of appropriate HLA-C C2 epitope. The risk of AD also increased for individuals with the HLA-B*-21T leader sequence. Future studies should focus on KIR gene allelic variation as well as consider cell-based measurements of KIR and the associated HLA class I epitopes.