Large scale meta-analysis characterizes genetic architecture for common psoriasis associated variants

Patients with PSOriasis and Suppurative Hidradenitis (PSO-SH) share genetic risk factors and are at risk of increased morbidity

BACKGROUND

Select patients are diagnosed with both psoriasis (PSO) and hidradenitis suppurativa (HS), leading to a unique disease pattern. Genetic risk factors remain unidentified.

METHODS

The study harnessed an international collection of patients with PSO and HS (PSO-SH). Clinical and genetic data were collected and analyzed.

RESULTS

Eighty-seven PSO-SH patients (70% female) were identified. They had a high number of comorbidities (89%) and worse general physical health compared to PSO-only (OR: 3.09; 95% CI: 1.56-6.12) or HS-only (OR: 2.5; 95% CI: 1.23-5.00) patients. PSO-SH patients were at significantly higher risk of having Crohn's disease (OR: 4.6-11.9; 95% CI). Data revealed the highest overall genetic risk score for PSO-SH patients (PSO-polygenic risk score; 108.22), followed by PSO (101.18), HS (99.84), and healthy controls (98.58). High non-human leukocyte antigen scores were associated with an increased risk for developing both PSO and HS, indicating a distinct biological profile compared to HS-only and PSO-only individuals.

LIMITATIONS

Some clinical information was collected retrospectively.

CONCLUSIONS

This study highlights a shared genetic susceptibility of HS and PSO at non-human leukocyte antigen loci. Recognizing PSO-SH patients as a distinct patient group with high morbidity and increased risk for developing Crohn's disease will help to improve patient management.

Cross-tissue transcriptome-wide association study reveals novel psoriasis susceptibility genes

Background

Psoriasis is a chronic, immune-mediated inflammatory skin disorder with a strong genetic component. Although numerous GWAS have identified risk loci, many associated variants lie in non-coding regions, complicating functional interpretation.

Objective

This study aimed to identify novel psoriasis susceptibility genes by integrating large-scale GWAS and eQTL data using a cross-tissue TWAS approach.

Methods

We integrated psoriasis GWAS summary statistics from the FinnGen database with GTEx V8 eQTL data. A cross-tissue TWAS was performed using UTMOST, followed by validation with single-tissue TWAS via FUSION. Conditional and joint analyses were conducted to delineate independent genetic signals, and gene-based analysis was performed using MAGMA. Causal relationships were evaluated using Mendelian randomization (MR) and Bayesian colocalization analyses. Key SNPs were functionally characterized using CADD, GERP++, and RegulomeDB for pathogenicity prediction and regulatory potential assessment. Finally, functional network analysis was conducted using GeneMANIA.

Results

The cross-tissue TWAS identified 259 genes significantly associated with psoriasis (p < 0.05), with 12 remaining significant after FDR correction. Single-tissue TWAS validation revealed 655 significant genes, with an overlap of three protein-coding candidates: POLI, NFKB1, and ZFYVE28. Cross-validation with MAGMA refined the candidate set to NFKB1 and ZFYVE28. MR and colocalization analyses supported a causal relationship for NFKB1 in Skeletal Muscle, Transverse Colon, and Cultured Fibroblasts, and for ZFYVE28 in Subcutaneous Adipose Tissue and Esophageal Mucosa tissues. Functional annotation identified key SNPs including rs4235405, rs3774960, and rs1598856 for NFKB1, and rs1203786 for ZFYVE28, with varying degrees of pathogenicity and regulatory potential. GeneMANIA network analysis further implicated NFKB1 in NF-κB signaling and ZFYVE28 in vesicle-mediated transport.

Conclusion

Our integrative multi-omics approach identifies NFKB1 and ZFYVE28 as novel psoriasis susceptibility genes, providing potential biomarkers and therapeutic targets for this complex disease.

Differentiating the Role of Inflammation in Hidradenitis Suppurativa from that in Other Inflammatory Skin Diseases

Hidradenitis suppurativa (HS) is a chronic, inflammatory skin disease characterized by nodules, abscesses, and sinus tunnels, primarily in intertriginous areas. Symptoms of HS are associated with reduced psychosocial health and physical function. HS shares some pathogenic, cellular, and molecular features with other inflammatory skin diseases, highlighting its heterogeneity and complexity. This heterogeneity in disease presentation may contribute to the diagnosis delay observed with HS. The primary objective of this review is to highlight the initiating events, inflammatory signature, molecular features, and clinical features that differentiate HS from other inflammatory skin diseases to improve outcomes for patients with HS.

The causal association between psoriasis and 32 types of cancer: a mendelian randomization study

BACKGROUND

Psoriasis is a systemic immune disease associated with the development of various cancers. However, the causal nature of this association remains unclear. This study aims to systematically investigate the potential causal relationship between psoriasis and 32 types of cancer.

METHODS

We utilized data from two large genomic databases, the UK Biobank and FinnGen, to extract GWAS summary statistics for 32 cancer types as outcomes and psoriasis-related data as exposures. Mendelian randomization (MR) analysis was performed to assess the causal effects of psoriasis on cancer risk. Sensitivity analyses, including heterogeneity and horizontal pleiotropy tests, were conducted to ensure robustness. Additionally, meta-analysis and FDR correction were applied to enhance the reliability of the results.

RESULTS

Our findings revealed significant causal relationships between psoriasis and four cancer types: Psoriasis was associated with an increased risk of laryngeal cancer (OR = 1.15, 95% CI: 1.05-1.26). Psoriasis exhibited a protective effect against oral cavity and pharyngeal cancer (OR: 0.91; 95% CI: 0.86-0.97), prostate cancer (OR: 0.97; 95% CI: 0.95-0.99), and malignant non-melanoma cancer (OR: 0.89; 95% CI: 0.82-0.96).

CONCLUSION

Psoriasis may exert bidirectional effects on the development of specific cancers through distinct mechanisms. Specifically, psoriasis may increase the risk of laryngeal cancer while reducing the risk of oral cavity and pharyngeal cancer, prostate cancer, and malignant non-melanoma cancer. These findings provide new insights into the causal relationship between psoriasis and cancer and could inform prevention and treatment strategies for these diseases.

Associations between psoriasis and risk of 33 cancers: a Mendelian randomization study

BACKGROUND

Several observational studies have reported epidemiologic associations between psoriasis and risk of some cancers, but systematic evidence is lacking. Our aim was to comprehensively estimate the association between psoriasis and the risk of 33 common cancers using systematical Mendelian randomization based on genetic data.

METHOD

Forty-nine independent single-nucleotide polymorphisms (SNPs) significantly associated with psoriasis were extracted as instrumental variables from a large-scale meta-analysis study of genome-wide association study (GWAS) for psoriasis. Outcome GWAS data were obtained from the FinnGen consortium (n = 500,348), UK Biobank (n = 420,531), and other large-scale cancer datasets. The inverse-variance weighted (IVW) was used as the primary method to infer the association between psoriasis and risk of cancer, and finally the results from multiple databases were pooled by meta-analysis.

RESULTS

In the UK Biobank, genetically predicted psoriasis had a suggestive association with colon (OR = 1.055, 95%CI: 1.001-1.113, P = 0.046) and uterine corpus cancer (OR = 0.922, 95%CI: 0.852-0.997, P = 0.042). In the FinnGen consortium, psoriasis had a suggestive association with vulvar cancer (OR = 1.182, 95%CI: 1.023-1.366, P = 0.024), uterine corpus cancer (OR = 0.937, 95%CI: 0.883-0.993, P = 0.028), and prostate cancer (OR = 0.973, 95%CI: 0.948-0.999, P = 0.045). In an additional large-scale cancer dataset, psoriasis also showed a suggestive association with prostate cancer (OR = 0.968, 95%CI:0.942-0.995, P = 0.020). The meta-analysis confirmed the suggestive association of psoriasis with uterine corpus (OR = 0.931, 95% CI: 0.889-0.976, P = 0.003) and prostate cancer (OR = 0.976, 95% CI: 0.955-0.997, P = 0.023). Whereas the effect of psoriasis on colon and vulvar cancer was not in the same direction across different populations. Furthermore, no association between genetically predicted psoriasis and other cancers were observed.

CONCLUSIONS

This comprehensive MR study suggests that psoriasis may be a potential protective factor for uterine corpus cancer in women and prostate cancer in men.

Identifying a Genetic Link Between Lung Function and Psoriasis

INTRODUCTION

The common genetic underpinnings of psoriasis and pulmonary comorbidities have yet to be explored.

MATERIAL AND METHODS

In this cross-sectional study, we investigated the single-nucleotide polymorphisms (SNPs) associated with psoriasis and their relationship with pulmonary function using data from the UK Biobank (UKBB) and the Vanderbilt University Medical Center Biobank (BioVU).

RESULTS

Out of the 63 psoriasis-associated SNPs identified in previous genome-wide association studies within the European population, we successfully identified 53 SNPs, including proxy SNPs in UKBB database. Following adjustments using age and sex, 31 SNPs displayed statistically significant associations with psoriasis. Among these, 16 SNPs exhibited significant associations with forced expiratory volume in 1 s (FEV1), 14 with forced vital capacity (FVC), and 5 with the FEV1/FVC ratio in the UKBB. In the validation analysis using the BioVU database, 27 of the 31 psoriasis-associated SNPs were available for examination. Notably, the minor allele of SNP rs8016947 was confirmed to be significant, indicating a reduced risk for psoriasis and improved FEV1. Similarly, the minor alleles of SNPs rs17716942 and rs8016947 were associated with a reduced risk of psoriasis and enhanced FVC. However, none of the 5 SNPs significantly associated with the FEV1/FVC ratio in the UKBB displayed significance in the BioVU dataset.

CONCLUSION

This study has unveiled genetic variants that bridge the realms of psoriasis and lung function. The genes associated with these variants, including IFIH1, Grancalcin gene (GCA), and NFKB inhibitor alpha gene (NFKBIA), regulate innate immune responses, which suggests that immunodysregulation, a central element in psoriasis pathogenesis, may also impact lung function, alluding to a "skin-lung axis."

Cholesterol pathway gene variants and reduced keratinocyte cholesterol support a final common druggable pathway in hyperproliferative inflammatory skin diseases

Hyperproliferative inflammatory skin disease (HISD) is frequently seen in rare monogenic diseases of cholesterol metabolism and responds to topical cholesterol/statin. We hypothesised that aberrant cholesterol metabolism within keratinocytes could be important in HISD more generally, driven by either immunological or lipid pathway genetic variation. Whilst other epidermal lipids have been well characterised in HISDs, cholesterol and its metabolites have not. Using GCxGC 3D mass spectrometry we find here that primary keratinocytes from diverse monogenic HISDs (Inflammatory Linear Verruvous Epidermal Naevus ILVEN n=14, CHILD syndrome n=2), and from plaque psoriasis (n=2), demonstrate significantly reduced mean cholesterol across all patient groups compared to controls. This striking abnormality appears causally implicated, as treatment in vitro with cholesterol and statin rescues the cellular hyperproliferation. Using SNPsea and burden analysis of large international psoriasis cohorts we go on to show that GWAS hits are significantly enriched in proximity to genes encoding lipid metabolic pathways, and that rare variants in lipid metabolic pathway genes are significantly enriched in psoriasis patients. These data identify a final common pathway of aberrant keratinocyte cholesterol metabolism in HISD, which should be drugged topically to avoid first pass metabolism. In parallel we implicate genetic variation in lipid pathway genes in psoriasis susceptibility, potentially explaining the co-morbidity of abnormal serum lipid profile and psoriasis.

Nutrition-induced changes in the microbiota can cause dysbiosis and disease development

Eukaryotic organisms are associated with complex microbial communities. Changes within these communities have been implicated in disease development. Nonetheless, it remains unclear whether these changes are a cause or a consequence of disease. Here, we report a causal link between environment-induced shifts in the microbiota and disease development. Using the model organism Hydra, we observed changes in microbial composition when transferring laboratory-grown Hydra to natural lake environments. These shifts were caused not only by new colonizers, through the process of community coalescence (merging of previously separate microbial communities), but also by lake water nutrients. Moreover, selective manipulation of the nutrient environment induced compound-specific shifts in the microbiota followed by disease development. Finally, L-arginine supplementation alone caused a transition in Pseudomonas from symbiotic to pathogenic, leading to an upregulation of immune response genes, tissue degradation, and host death. These findings challenge the notion that the host-associated microbiota is exclusively controlled by the host, highlighting the dynamic interplay between host epithelial environment, microbial colonizer pool, and nutrient conditions of the surrounding water. Furthermore, our results show that overfeeding of the microbiota allows for uncontrolled microbial growth and versatile interactions with the host. Environmental conditions may thus render symbionts a potential hazard to their hosts, blurring the divide between pathogenic and non-pathogenic microbes.IMPORTANCEThis study highlights the critical need to understand the dynamic interplay between host-associated microbiota and environmental factors to obtain a holistic view on organismal health. Our results demonstrate that ecosystem-wide microbial trafficking (community coalescence) and environmental nutrient conditions reshape microbial communities with profound implications for host health. By exploring nutrient-driven changes in microbial composition, our research finds experimental support for the "overfeeding hypothesis," which states that overfeeding alters the functionality of the host microbiota such that an overabundance in nutrients can facilitate disease development, transforming non-pathogenic microbes into pathogens. These findings emphasize the critical role of metabolic interactions driving microbial pathogenicity. Furthermore, our research provides empirical evidence for the "pathogenic potential" concept, challenging traditional distinctions between pathogenic and non-pathogenic microbes and supporting the idea that any microbe can become pathogenic under certain conditions.

Identification of novel IL17-related genes as prognostic and therapeutic biomarkers of psoriasis using comprehensive bioinformatics analysis and machine learning

Psoriasis is a common chronic skin disorder with a polygenic background. It is widely acknowledged that Th17/IL-17A axis plays a key role in the pathogenesis of psoriasis. However, numerous regulatory genes upstream of the pathway remain undiscovered, creating a knowledge gap in our understanding of the genetic aspects of the Th17/IL-17A axis. In this study, we employed machine learning algorithms to identify three target genes associated with psoriasis: CCR7, IL2RG, and PLEK. The validation of these genes was carried out in specimens from psoriatic patients. In vivo, investigations assessed the relationship between these three genes and IL-17A-related inflammation and their connection to psoriatic phenotypes. To further confirm the significance of the newly discovered gene, PLEK, we performed experiments involving the blockade of its expression. Our bioinformatics analysis revealed three novel genes closely linked to psoriasis: CCR7, IL2RG, and PLEK. These genes exhibited upregulated expression in psoriasis, consistently aligning with the Th17/IL-17A axis. Inhibition of PLEK expression reduced Th17/IL-17A-related inflammation and alleviated psoriatic phenotypes. CCR7, IL2RG, and PLEK show potential as three novel biomarkers for psoriasis, with PLEK being reported for the first time in this context. These genes contribute to pathogenesis by associating with the Th17/IL-17A signaling pathway.

GWAS meta-analysis of psoriasis identifies new susceptibility alleles impacting disease mechanisms and therapeutic targets

Psoriasis is a common, debilitating immune-mediated skin disease. Genetic studies have identified biological mechanisms of psoriasis risk, including those targeted by effective therapies. However, the genetic liability to psoriasis is not fully explained by variation at robustly identified risk loci. To refine the genetic map of psoriasis susceptibility we meta-analysed 18 GWAS comprising 36,466 cases and 458,078 controls and identified 109 distinct psoriasis susceptibility loci, including 46 that have not been previously reported. These include susceptibility variants at loci in which the therapeutic targets IL17RA and AHR are encoded, and deleterious coding variants supporting potential new drug targets (including in STAP2, CPVL and POU2F3). We conducted a transcriptome-wide association study to identify regulatory effects of psoriasis susceptibility variants and cross-referenced these against single cell expression profiles in psoriasis-affected skin, highlighting roles for the transcriptional regulation of haematopoietic cell development and epigenetic modulation of interferon signalling in psoriasis pathobiology.

Joint exposure to multiple air pollutants, genetic risk and incident psoriasis: a large-scale prospective cohort study

BACKGROUND

Air pollution and genetic risk have been found to contribute to the onset and development of psoriasis. However, the extent to which genetic susceptibility modifies the effects of air pollutants on the risk of incident psoriasis remains unknown.

OBJECTIVES

To assess the association between joint exposure to multiple air pollutants and the risk of psoriasis, and its modification, according to genetic susceptibility.

METHODS

This prospective study included 451 064 participants from the UK Biobank who had complete air pollution data and were free of psoriasis at baseline. All participants were enrolled from 2006 to 2010 and followed up to 2022. An air pollution score (APS) was calculated to assess joint exposure to multiple air pollutants, including fine particulate matter (PM) with diameters ≤ 2.5 μm (PM2.5), between 2.5 and 10 μm (PM2.5-10) and ≤ 10 μm (PM10), as well as nitrogen dioxide (NO2) and nitrogen oxides (NOx). To evaluate the genetic risk, a polygenic risk score (PRS) for psoriasis was constructed. Cox proportional hazard models were used to assess the association of air pollution and genetic susceptibility with the risk of psoriasis. Stratified analyses were conducted based on the individual characteristics.

RESULTS

During a median follow-up of 13.79 years (range 0.00-16.81), 4414 cases of psoriasis were recorded. The hazard ratios (HRs) for psoriasis were 1.036 [95% confidence interval (CI) 0.936-1.147], 1.091 (95% CI 0.987-1.206), 1.159 (95% CI 1.048-1.283) and 1.163 (95% CI 1.052-1.286) in the higher APS quintile groups (Q2, Q3, Q4 and Q5, respectively) vs. the lowest APS quintile (Q1; P-value for trend < 0.05). When considering genetic susceptibility, participants with a high PRS and a high APS had the greatest risk of incident psoriasis (HR 1.962, 95% CI 1.630-2.362) vs. those with a low PRS and low APS. The HRs for PM2.5-10, NOx, PM2.5 absorbance, PM2.5, NO2 and PM10 in the group with the highest exposure level and genetic risk were 1.831 (95% CI 1.537-2.181), 1.722 (95% CI 1.431-2.073), 1.698 (95% CI 1.416-2.037), 1.619 (95% CI 1.353-1.938), 1.504 (95% CI 1.252-1.806) and 1.425 (95% CI 1.192-1.704), respectively.

CONCLUSIONS

Long-term exposure to various air pollutants is positively associated with an increased risk of incident psoriasis, particularly in individuals with a high genetic risk of the disease. More comprehensive measures are needed to reduce the air pollution levels for better prevention of psoriasis.

Multi-omics analysis in primary T cells elucidates mechanisms behind disease-associated genetic loci

BACKGROUND

Genome-wide association studies (GWAS) have uncovered the genetic basis behind many diseases and conditions. However, most of these genetic loci affect regulatory regions, making the interpretation challenging. Chromatin conformation has a fundamental role in gene regulation and is frequently used to associate potential target genes to regulatory regions. However, previous studies mostly used small sample sizes and immortalized cell lines instead of primary cells.

RESULTS

Here we present the most extensive dataset of chromatin conformation with matching gene expression and chromatin accessibility from primary CD4+ and CD8+ T cells to date, isolated from psoriatic arthritis patients and healthy controls. We generated 108 Hi-C libraries (49 billion reads), 128 RNA-seq libraries and 126 ATAC-seq libraries. These data enhance our understanding of the mechanisms by which GWAS variants impact gene regulation, revealing how genetic variation alters chromatin accessibility and structure in primary cells at an unprecedented scale. We refine the mapping of GWAS loci to implicated regulatory elements, such as CTCF binding sites and other enhancer elements, aiding gene assignment. We uncover BCL2L11 as the probable causal gene within the rheumatoid arthritis (RA) locus rs13396472, despite the GWAS variants' intronic positioning relative to ACOXL, and we identify mechanisms involving SESN3 dysregulation in the RA locus rs4409785.

CONCLUSIONS

Given these genes' significant role in T cell development and maturation, our work deepens our comprehension of autoimmune disease pathogenesis, suggesting potential treatment targets. In addition, our dataset provides a valuable resource for the investigation of immune-mediated diseases and gene regulatory mechanisms.

Associations between domestic hard water exposure and incident psoriasis in adults: Insights from the UK Biobank cohort study

Although exposure to hard water is associated with various inflammatory skin conditions, the specific relationship between hard water and psoriasis has not been clearly defined. We analyzed data from 486,414 participants in the UK Biobank cohort to explore the association between domestic hard water exposure and the incidence of psoriasis. Domestic water hardness, measured in calcium carbonate concentration, was obtained in 2005 from local water providers in Wales, Scotland, and England. During a median follow-up period of approximately 14 years, a total of 4801 (1.0 %) participants reported psoriasis, and we observed that for every 50 mg/L increase in water hardness (as CaCO₃), there was a 3 % increase in the risk of psoriasis [Hazard Ratio (HR) = 1.03, 95 % Confidence Interval (CI) 1.01-1.06]. Individuals exposed to very hard water (>180 mg/L) exhibited a 20 % increased risk of psoriasis compared to those exposed to soft water (0-60 mg/L) [HR: 1.20, 95 % CI: 1.07-1.34]. A positive linear relationship was observed between water hardness and the risk of psoriasis. Furthermore, the polygenic risk score indicated a synergistic effect between hard water exposure and genetic risk factors in developing psoriasis. Subgroup analysis suggested that the effect of hard water on psoriasis is more pronounced in individuals with a low polygenic risk score, women, the elderly, non-obese individuals, those of high socioeconomic status or without dyslipidemia. Residential water hardness has been identified as a significant risk factor for psoriasis in adults. Sustained efforts to reduce exposure to hard water may alleviate the psoriasis burden.

Multi-ancestry genome-wide meta-analysis with 472,819 individuals identifies 32 novel risk loci for psoriasis

BACKGROUND

Psoriasis is a common chronic, recurrent, immune-mediated disease involved in the skin or joints or both. However, deeper insight into the genetic susceptibility of psoriasis is still unclear.

METHODS

Here we performed the largest multi-ancestry meta-analysis of genome-wide association study including 28,869 psoriasis cases and 443,950 healthy controls.

RESULTS

We identified 74 genome-wide significant loci for psoriasis. Of 74 loci, 32 were novel psoriasis risk loci. Across 74 loci, 801 likely causal genes are indicated and 164 causal genes are prioritized. SNP-based heritability analyses demonstrated that common variants explain 15% of genetic risk for psoriasis. Gene-set analyses and the genetic correlation revealed that psoriasis-related genes have the positive correlations with autoimmune diseases such as ulcerative colitis, inflammatory bowel diseases, and Crohn's disease. Gene-drug interaction analysis suggested that psoriasis-associated genes overlapped with targets of current medications for psoriasis. Finally, we used the multi-ancestry meta-analysis to explore drug repurposing and the potential targets for psoriasis.

CONCLUSIONS

We identified 74 genome-wide significant loci for psoriasis. Based on 74 loci, we provided new biological insights to the etiology of psoriasis. Of clinical interest, we gave some hints for 76 potential targets and drug repurposing for psoriasis.

IL-1 signaling enrichment in inflammatory skin disease loci with higher-risk allele frequencies in African ancestry

Inflammatory skin diseases (ISDs) exhibit varying prevalence across different ancestry background and geographical regions. Genetic research for complex ISDs has predominantly centered on European Ancestry (EurA) populations and genetic effects on immune cell responses but generally failed to consider contributions from other cell types in skin. Here, we utilized 273 genetic signals from seven different ISDs: acne, alopecia areata (AA), atopic dermatitis (AD), psoriasis, systemic lupus erythematosus (SLE), systemic sclerosis (SSc), and vitiligo, to demonstrate enriched IL1 signaling in keratinocytes, particularly in signals with higher risk allele frequencies in the African ancestry. Using a combination of ATAC-seq, Bru-seq, and promoter capture Hi-C, we revealed potential regulatory mechanisms of the acne locus on chromosome 2q13. We further demonstrated differential responses in keratinocytes upon IL1β stimulation, including the pro-inflammatory mediators CCL5, IL36G, and CXCL8. Taken together, our findings highlight IL1 signaling in epidermal keratinocytes as a contributor to ancestry-related differences in ISDs.

Characterising a Novel Therapeutic Target for Psoriasis, TYK2, Using Functional Genomics

Psoriasis (Ps) is a debilitating immune-mediated chronic skin condition. It affects about 1-3% of the world population, with an 8-11% prevalence in Northern European populations. Tyrosine kinase 2 (TYK2) is a newly identified target for Ps. An independent non-coding genetic association with Ps has been identified ~400 kb upstream of TYK2. The variants making up the credible Ps Single-Nucleotide Polymorphism (SNP) set were identified in their genomic context with the potential to influence TYK2 expression by interacting with regulatory elements involved in gene regulation. Previous evidence from our laboratory has suggested that credible SNP sets in intronic regions can be distal regulators of the genes of interest through long-range chromatin interactions. We hypothesise that SNPs at ILF3 are distal regulators of TYK2 expression via long-range chromatin interactions and Ps risk. The dysregulation of the TYK2 pathway in Ps may be mediated by a combination of GWAS risk SNPs at ILF3 and TYK2 and downstream genes. We investigated this by employing functional genomics and molecular biology methods. We developed a CD4 T cell model system with Jurkat-dCAS9-VP64 and Jurkat-dCAS9-KRAB cells using CRISPR activation and CRISPR inhibition of the risk variants rs892086 and rs7248205, selected from the latest Ps GWAS SNP set for their long-range interaction and light Linkage Disequilibrium (R2 > 0.8), respectively. Using CRISPR activation, we demonstrate here that these risk SNPs, although distal to TYK2, do indeed regulate the TYK2 gene. Investigations into annotating the TYK2 pathway using RNA-seq analysis revealed differentially regulated genes, including VEGFA, C1R, ADORA1, GLUD2, NDUFB8, and FCGR2C, which are thought to be implicated in Ps. These genes were observed to be associated with conditions such as psoriatic arthritis, atopic dermatitis, and systemic sclerosis when compared using published databases, which confirms their relevance and importance in inflammatory conditions. With the developed cell model systems using CRISPR technology and differential gene regulation, we demonstrate here that these genes have the potential to define the TYK2/Ps pathway and our understanding of the disease biology.

Unveiling Novel Protein Biomarkers for Psoriasis Through Integrated Analysis of Human Plasma Proteomics and Mendelian Randomization

Background

Current pharmacological treatments for psoriasis are generally non-specific and have significant limitations, particularly in the realm of targeted biologic therapies. There is an urgent need to identify and develop new therapeutic targets to improve treatment options.

Objective

The aim of this study was to explore the proteome associated with psoriasis in large population cohorts to discover novel biomarkers that could guide therapy.

Methods

We analyzed data from 54,306 participants enrolled in the UK Biobank Pharmacological Proteomics Project (UKB-PPP). We investigated the relationship between 2923 serum proteins and the risk of psoriasis using multivariate Cox regression models initially. This was complemented by two-sample Mendelian randomization (TSMR), Summary-data-based Mendelian Randomization (SMR), and coloc colocalization studies to identify genetic correlations with protein targets linked to psoriasis. A protein scoring system was created using the Cox proportional hazards model, and cumulative risk curves were generated to analyze psoriasis incidence variations.

Results

Our study pinpointed 62 proteins significantly linked to the risk of developing psoriasis. Further analysis through TSMR narrowed these down to ten proteins with strong causal relationships to the disease. Additional deep-dive analyses such as SMR, colocalization, and differential expression studies highlighted four critical proteins (MMP12, PCSK9, PRSS8, and SCLY). We calculated a protein score based on the levels of these proteins, with higher scores correlating with increased risk of psoriasis.

Conclusion

This study's integration of proteomic and genetic data from a European adult cohort provides compelling evidence of several proteins as viable predictive biomarkers and potential therapeutic targets for psoriasis, facilitating the advancement of targeted treatment strategies.

Genetic Study of Psoriasis Highlights its Close Link with Socioeconomic Status and Affective Symptoms

Psoriasis is an inflammatory skin disease with an estimated heritability of around 70%. Previous GWASs have detected several risk loci for psoriasis. To further improve the understanding of the genetic risk factors impacting the disease, we conducted a discovery GWAS in FinnGen and a subsequent replication and meta-analysis with data from the Estonian Biobank and the UK Biobank; the study sample included 925,649 individuals (22,659 cases and 902,990 controls), the largest sample for psoriasis yet. In addition, we conducted downstream analyses to find out more about psoriasis' cross-trait genetic correlations and causal relationships. We report 6 risk loci, which, to our knowledge, are previously unreported, most of which harbor genes related to NF-κB signaling pathway and overall immunity. Genetic correlations highlight the relationship between psoriasis and smoking, higher body weight, and lower education level. In addition, we report causal relationships between psoriasis and mood symptoms as well as 2-directioned causal relationship between psoriasis and lower education level. Our results provide further knowledge on psoriasis risk factors, which may be useful in the development of future treatment strategies.

Life's Essential 8, genetic susceptibility and the risk of psoriatic disease: a prospective cohort study

BACKGROUND

Psoriatic disease (PsD) is closely associated with cardiovascular (CV) disease. The Life's Essential 8 (LE8) score is a new metric to assess CV health (CVH), where a higher score indicates better CVH. However, the longitudinal association between LE8 score and the risk of PsD remains uncertain.

OBJECTIVES

To investigate, in a cohort study, the association between LE8 score, genetic susceptibility and the risk of PsD.

METHODS

This cohort study included 261 642 participants in the UK Biobank without PsD at baseline. LE8 comprises eight indicators: diet, physical activity, nicotine exposure, sleep health, body mass index, blood lipids, blood glucose and blood pressure. Cox proportional hazard models were used to examine the association between participants' LE8 scores, genetic risk of PsD and the risk of PsD. Hazard ratios (HRs) and 95% confidence intervals (CIs) were calculated.

RESULTS

During an average follow-up of 12.3 years, 1501 participants developed PsD. Compared with participants with low LE8 scores, the HRs of developing PsD for those with moderate and high LE8 scores were 0.51 (95% CI 0.43-0.59) and 0.34 (95% CI 0.27-0.42) after adjustments, respectively. Dose-response analysis revealed a linear negative association between continuous LE8 score and the risk of developing PsD (P < 0.001), with no evidence of nonlinear association detected. Genetic susceptibility to PsD did not modify this association (P-interaction = 0.63). Subgroup analyses revealed that women had a more pronounced beneficial association between LE8 scores and PsD risk (P-interaction = 0.02).

CONCLUSIONS

Our study suggests that a higher LE8 score, regardless of genetic risk, is associated with a lower risk of PsD, particularly in women. Consequently, maintaining good CVH status is recommended to prevent PsD and assess associated risks.

Genome-wide meta-analysis of myasthenia gravis uncovers new loci and provides insights into polygenic prediction

Myasthenia gravis (MG) is a rare autoantibody-mediated disease affecting the neuromuscular junction. We performed a genome-wide association study of 5708 MG cases and 432,028 controls of European ancestry and a replication study in 3989 cases and 226,643 controls provided by 23andMe Inc. We identified 12 independent genome-wide significant hits (P < 5e-8) across 11 loci. Subgroup analyses revealed two of these were associated with early-onset (at age <50) and four with late-onset MG (at age ≥ 50). Imputation of human leukocyte antigen alleles revealed inverse effect sizes for late- and early-onset, suggesting a potential modulatory influence on the time of disease manifestation. We assessed the performance of polygenic risk scores for MG, which significantly predicted disease status in an independent target cohort, explaining 4.21% of the phenotypic variation (P = 5.12e-9). With this work, we aim to enhance our understanding of the genetic architecture of MG.

Inverse relationship between polygenic risk burden and age of onset of autoimmune vitiligo

Vitiligo is a common autoimmune disease characterized by patches of depigmented skin and overlying hair due to destruction of melanocytes in the involved regions. We investigated the relationship between vitiligo risk and vitiligo age of onset (AOO) using a vitiligo polygenic risk score that incorporated the most significant SNPs from genome-wide association studies. We find that vitiligo genetic risk and AOO are strongly inversely correlated; subjects with higher common-variant polygenic risk tend to develop vitiligo at an earlier age. Nevertheless, the correlation is not simple. In individuals who carry a single high-risk major histocompatibility complex class II haplotype, the effect of additional polygenic risk on vitiligo AOO is reduced. Particularly among those with early-AOO vitiligo (onset ≤12 years of age), genetic risk can reflect contributions from high common-variant burden but also rare variants of high effect and sometimes both. While the heritability of vitiligo is relatively high, and we here show that genetic risk factors predict vitiligo AOO, vitiligo is never congenital, and thus environmental triggers also play an important role in disease onset.

A polygenic risk score model for psoriasis based on the protein interactions of psoriasis susceptibility loci

Introduction

Polygenic Risk Scores (PRS) are an emerging tool for predicting an individual's genetic risk to a complex trait. Several methods have been proposed to construct and calculate these scores. Here, we develop a biologically driven PRS using the UK BioBank cohort through validated protein interactions (PPI) and network construction for psoriasis, incorporating variants mapped to the interacting genes of 14 psoriasis susceptibility (PSORS) loci, as identified from previous genetic linkage studies.

Methods

We constructed the PPI network via the implementation of two major meta-databases of protein interactions, and identified variants mapped to the identified PSORS-interacting genes. We selected only European unrelated participants including individuals with psoriasis and randomly selected healthy controls using an at least 1:4 ratio to maximize statistical power. We next compared our PPI-PRS model to (i) clinical risk models and (ii) conventional PRS calculations through p-value thresholding.

Results

Our PPI-PRS model provides comparable results to both clinical risk models and conventional approaches, despite the incorporation of a limited number of variants which have not necessarily reached genome-wide significance (GWS). Exclusion of variants mapped to the HLA-C locus, an established risk locus for psoriasis resulted in highly similar associations compared to our primary model, indicating the contribution of the genetic variability mapped to non-GWS variants in PRS computations.

Discussion

Our findings support the implementation of biologically driven approaches in PRS calculations in psoriasis, highlighting their potential clinical utility in risk assessment and treatment management.

Targeting TNF/TNFR superfamilies in immune-mediated inflammatory diseases

Dysregulated signaling from TNF and TNFR proteins is implicated in several immune-mediated inflammatory diseases (IMIDs). This review centers around seven IMIDs (rheumatoid arthritis, systemic lupus erythematosus, Crohn's disease, ulcerative colitis, psoriasis, atopic dermatitis, and asthma) with substantial unmet medical needs and sheds light on the signaling mechanisms, disease relevance, and evolving drug development activities for five TNF/TNFR signaling axes that garner substantial drug development interest in these focus conditions. The review also explores the current landscape of therapeutics, emphasizing the limitations of the approved biologics, and the opportunities presented by small-molecule inhibitors and combination antagonists of TNF/TNFR signaling.

Skin-resident T Cells Contribute to the Dynamic Disease Manifestations of Psoriasis

The human skin forms a dynamic barrier to physical injuries and microbial invasion. Constant interactions between stroma and tissue-confined immune cells maintain skin homeostasis. However, the cellular interactions that maintain skin health also contribute to focal immunopathology. Psoriasis is a common disease that manifests with focal pathology induced by environmental triggers in genetically susceptible individuals. Within psoriasis plaques, cross-talk between skin-resident T cells and stroma cells leads to chronic inflammation. Inflammatory cytokines such as TNF-α, IL-17, IL-22, and IL-23 amplify the local chronic inflammation and sustain the well-demarcated thick and scaly plaques that characterize the disease. In resolved lesions, T cells remain poised for IL-17 and IL-22 production, and postinflammatory epigenetic modifications lower the threshold for initiation of local relapse. This review focuses on how tissue-resident memory T cells contribute to the onset, maintenance, resolution, and relapse of psoriasis.

Autoimmune Diseases and Risk of Non-Hodgkin Lymphoma: A Mendelian Randomisation Study

BACKGROUND

Non-Hodgkin lymphoma (NHL) is one of the most common haematologic malignancies in the world. Despite substantial efforts to identify causes and risk factors for NHL, its aetiology is largely unclear. Autoimmune diseases have long been considered potential risk factors for NHL. We carried out Mendelian randomisation (MR) analyses to examine whether genetically predicted susceptibility to ten autoimmune diseases (Behçet's disease, coeliac disease, dermatitis herpetiformis, lupus, psoriasis, rheumatoid arthritis, sarcoidosis, Sjögren's syndrome, systemic sclerosis, and type 1 diabetes) is associated with risk of NHL.

METHODS

Two-sample MR was performed using publicly available summary statistics from cohorts of European ancestry. For NHL and four NHL subtypes, we used data from UK Biobank, Kaiser Permanente cohorts, and FinnGen studies.

RESULTS

Negative associations between type 1 diabetes and sarcoidosis and the risk of NHL were observed (odds ratio [OR] 0.95, 95% confidence interval [CI]: 0.92-0.98, p = 5 × 10-3, and OR 0.92, 95% CI: 0.85-0.99, p = 2.8 × 10-2, respectively). These findings were supported by the sensitivity analyses accounting for potential pleiotropy and weak instrument bias. No significant associations were found between the other eight autoimmune diseases and NHL risk.

CONCLUSION

These findings suggest that genetically predicted susceptibility to type 1 diabetes, and to some extent sarcoidosis, might reduce the risk of NHL. However, future studies with different datasets, approaches, and populations are warranted to further examine the potential associations between these autoimmune diseases and the risk of NHL.

Association between Life's Essential 8 and psoriasis in US adults: a cross-sectional study

Background

Psoriasis is closely associated with cardiovascular disease (CVD). However, the current evidence on the correlation between Life's Essential 8 and Psoriasis is insufficient. Our aim was to investigate the relationship between Life's Essential 8 (LE8), a measure of cardiovascular health (CVH), and psoriasis.

Objective

This study aimed to clarify the impact of Life's Essential 8 on Psoriasis and explore its implications.

Methods

This population-based cross-sectional study included 9,876 US adults aged 20 to 59 years from the National Health and Nutrition Examination Survey (NHANES) 2003-2006 and 2009-2014 cycles. The LE8 score comprises 8 metrics and was categorized into low, moderate, and high CVH. Logistic regression and restricted cubic splines (RCS) were used to assess the association between LE8 score and psoriasis.

Results

Among the 9,876 participants, those with moderate and high CVH had higher risks of psoriasis compared to low CVH. Additionally, every 10-point increase in the LE8 score was associated with a 10% reduced risk of psoriasis. Interaction was observed between gender, age, education level, race/ethnicity, marital status, and PIR.

Conclusion

LE8 and its subscale scores were strongly negatively related to the risk of psoriasis. Encouraging optimal CVH levels may be advantageous in reducing the incidence of psoriasis.

A genome-wide association study identified PTPN2 as a population-specific susceptibility gene locus for primary biliary cholangitis

BACKGROUND AND AIMS

Previous genome-wide association studies (GWAS) have indicated the involvement of shared (population-nonspecific) and nonshared (population-specific) susceptibility genes in the pathogenesis of primary biliary cholangitis (PBC) among European and East-Asian populations. Although a meta-analysis of these distinct populations has recently identified more than 20 novel PBC susceptibility loci, analyses of population-specific genetic architecture are still needed for a more comprehensive search for genetic factors in PBC.

APPROACH AND RESULTS

Protein tyrosine phosphatase nonreceptor type 2 ( PTPN2) was identified as a novel PBC susceptibility gene locus through GWAS and subsequent genome-wide meta-analysis involving 2181 cases and 2699 controls from the Japanese population (GWAS-lead variant: rs8098858, p = 2.6 × 10 -8 ). In silico and in vitro functional analyses indicated that the risk allele of rs2292758, which is a primary functional variant, decreases PTPN2 expression by disrupting Sp1 binding to the PTPN2 promoter in T follicular helper cells and plasmacytoid dendritic cells. Infiltration of PTPN2-positive T-cells and plasmacytoid dendritic cells was confirmed in the portal area of the PBC liver by immunohistochemistry. Furthermore, transcriptomic analysis of PBC-liver samples indicated the presence of a compromised negative feedback loop in vivo between PTPN2 and IFNG in patients carrying the risk allele of rs2292758.

CONCLUSIONS

PTPN2 , a novel susceptibility gene for PBC in the Japanese population, may be involved in the pathogenesis of PBC through an insufficient negative feedback loop caused by the risk allele of rs2292758 in IFN-γ signaling. This suggests that PTPN2 could be a potential molecular target for PBC treatment.

Identifying genetic variants that influence the abundance of cell states in single-cell data

Disease risk alleles influence the composition of cells present in the body, but modeling genetic effects on the cell states revealed by single-cell profiling is difficult because variant-associated states may reflect diverse combinations of the profiled cell features that are challenging to predefine. We introduce Genotype-Neighborhood Associations (GeNA), a statistical tool to identify cell-state abundance quantitative trait loci (csaQTLs) in high-dimensional single-cell datasets. Instead of testing associations to predefined cell states, GeNA flexibly identifies the cell states whose abundance is most associated with genetic variants. In a genome-wide survey of single-cell RNA sequencing peripheral blood profiling from 969 individuals, GeNA identifies five independent loci associated with shifts in the relative abundance of immune cell states. For example, rs3003-T (P = 1.96 × 10-11) associates with increased abundance of natural killer cells expressing tumor necrosis factor response programs. This csaQTL colocalizes with increased risk for psoriasis, an autoimmune disease that responds to anti-tumor necrosis factor treatments. Flexibly characterizing csaQTLs for granular cell states may help illuminate how genetic background alters cellular composition to confer disease risk.

A partitioned polygenic risk score reveals distinct contributions to psoriasis clinical phenotypes across a multi-ethnic cohort

Psoriasis is a chronic, immune-mediated inflammatory skin disease associated with a polygenic mode of inheritance. There are few studies that explore the association of a psoriasis Polygenic Risk Score (PRS) with patient clinical characteristics, and to our knowledge there are no studies examining psoriasis PRS associations across different ethnicities. In this study, we used a multi-racial psoriasis cohort to investigate PRS associations with clinical phenotypes including age of onset, psoriatic arthritis, other comorbidities, psoriasis body location, psoriasis subtype, environmental triggers, and response to therapies. We collected patient data and Affymetrix genome-wide SNP data from a cohort of 607 psoriasis patients and calculated an 88-loci PRS (PRS-ALL), also partitioned between genetic loci within the HLA region (PRS-HLA; 11 SNPS) and loci outside the HLA region (PRS-NoHLA; 77 SNPS). We used t-test and logistic regression to analyze the association of PRS with clinical phenotypes. We found that PRS-HLA and PRS-noHLA had differing effects on psoriasis age of onset, psoriatic arthritis, psoriasis located on the ears, genitals, nails, soles of feet, skin folds, and palms, skin injury as an environmental trigger, cardiovascular comorbidities, and response to phototherapy. In some cases these PRS associations were ethnicity specific. Overall, these results show that the genetic basis for clinical manifestations of psoriasis are driven by distinct HLA and non-HLA effects, and that these PRS associations can be dependent on ethnicity.

A genome-wide meta-analysis of palmoplantar pustulosis implicates TH2 responses and cigarette smoking in disease pathogenesis

BACKGROUND

Palmoplantar pustulosis (PPP) is an inflammatory skin disorder that mostly affects smokers and manifests with painful pustular eruptions on the palms and soles. Although the disease can present with concurrent plaque psoriasis, TNF and IL-17/IL-23 inhibitors show limited efficacy. There is therefore a pressing need to uncover PPP disease drivers and therapeutic targets.

OBJECTIVES

We sought to identify genetic determinants of PPP and investigate whether cigarette smoking contributes to disease pathogenesis.

METHODS

We performed a genome-wide association meta-analysis of 3 North-European cohorts (n = 1,456 PPP cases and 402,050 controls). We then used the scGWAS program to investigate the cell-type specificity of the association signals. We also undertook genetic correlation analyses to examine the similarities between PPP and other immune-mediated diseases. Finally, we applied Mendelian randomization to analyze the causal relationship between cigarette smoking and PPP.

RESULTS

We found that PPP is not associated with the main genetic determinants of plaque psoriasis. Conversely, we identified genome-wide significant associations with the FCGR3A/FCGR3B and CCHCR1 loci. We also observed 13 suggestive (P < 5 × 10-6) susceptibility regions, including the IL4/IL13 interval. Accordingly, we demonstrated a significant genetic correlation between PPP and TH2-mediated diseases such as atopic dermatitis and ulcerative colitis. We also found that genes mapping to PPP-associated intervals were preferentially expressed in dendritic cells and often implicated in T-cell activation pathways. Finally, we undertook a Mendelian randomization analysis, which supported a causal role of cigarette smoking in PPP.

CONCLUSIONS

The first genome-wide association study of PPP points to a pathogenic role for deregulated TH2 responses and cigarette smoking.

IL23R mutations associated with decreased risk of psoriasis lead to the differential expression of genes implicated in the disease

Psoriasis is an incurable immune-mediated skin disease, affecting around 1%-3% of the population. Various lines of evidence implicate IL23 as being pivotal in disease. Genetic variants within the IL23 receptor (IL23R) increase the risk of developing psoriasis, and biologic therapies specifically targeting IL23 demonstrated high efficacy in treating disease. IL23 acts via the IL23R, signalling through the STAT3 pathway, mediating the cascade of events that ultimately results in the clinical presentation of psoriasis. Given the essential role of IL23R in disease, it is important to understand the impact of genetic variants on receptor function with respect to downstream gene regulation. Here we developed model systems in CD4+ (Jurkat) and CD8+ (MyLa) T cells to express either the wild type risk or mutant (R381Q) protective form of IL23R. After confirmation that the model system expressed the genes/proteins and had a differential effect on the phosphorylation of STAT3, we used RNAseq to explore differential gene regulation, in particular for genes implicated with risk to psoriasis, at a single time point for both cell types, and in a time course experiment for Jurkat CD4+ T cells. These experiments discovered differentially regulated genes in the cells expressing wild type and mutant IL23R, including HLA-B, SOCS1, RUNX3, CCR5, CXCR3, CCR9, KLF3, CD28, IRF, SOCS6, TNFAIP and ICAM5, that have been implicated in both the IL23 pathway and psoriasis. These genes have the potential to define a IL23/psoriasis pathway in disease, advancing our understanding of the biology behind the disease.

Spatial distribution of residential environment, genetic susceptibility, and psoriasis: A prospective cohort study

Background

Genetic and environmental factors contribute to psoriasis, but the impact of residential environments on this condition remains uncertain. We aimed to investigate the association of residential environments with psoriasis risk and explore its interaction with genes.

Methods

We retrieved data on the spatial distribution of residential environments at 300 and 1000 m buffer zones from the UK Biobank, including the proportions of natural environments, domestic gardens, green spaces, and blue spaces within these zones. We then used Cox hazard models to estimate the hazard ratios (HRs) and 95% confidence intervals (CIs) for the associations between residential environments and psoriasis risk. Lastly, we constructed polygenic risk scores to determine genetic susceptibility and further analyse the interaction with residential environments.

Results

Overall, 3755 incident cases of psoriasis were documented during a median follow-up of 12.45 years. Compared with the lowest exposure quantile (Q1), Q4 exposure to natural environments (1000 m buffer: HR = 1.16, 95% CI = 1.05-1.29; 300 m buffer: HR = 1.12, 95% CI = 1.02-1.24) and green spaces (1000 m buffer: HR = 1.16, 95% CI = 1.04-1.28; 300m buffer: HR = 1.10, 95% CI = 1.00-1.21) increased the risk of psoriasis, while Q4 exposure to domestic gardens (1000 m buffer: HR = 0.85, 95% CI = 0.77-0.93; 300m buffer: HR = 0.91, 95% CI = 0.83-1.00) and Q3 exposure to blue spaces (1000 m buffer: HR = 0.89, 95% CI = 0.81-0.98) were negatively associated with psoriasis risk. Among participants with a high genetic risk, those exposed to high levels of natural environments (1000 m buffer: HR = 1.49, 95% CI = 1.15-1.93; 300 m buffer: HR = 1.39, 95% CI = 1.10-1.77) and green spaces (300 m buffer: HR = 1.30, 95% CI = 1.04-1.64) had a higher risk of psoriasis, while those exposed to blue spaces (1000 m buffer: HR = 0.78, 95% CI = 0.63-0.98) had a lower risk of psoriasis. We also observed joint effects of genetic risk and residential environments and an antagonistic additive interaction between blue spaces and genetic risk (P = 0.011).

Conclusions

We observed that residing in natural environments and green areas increased the risk of psoriasis in our sample, while proximity to blue spaces and domestic gardens was associated to reduced risks. The association of residential environments with psoriasis risk was modified by genetic susceptibility.

Cell death as an architect of adult skin stem cell niches

Our skin provides a physical and immunological barrier against dehydration and environmental insults ranging from microbial attacks, toxins and UV irradiation to wounding. Proper functioning of the skin barrier largely depends on the interplay between keratinocytes- the epithelial cells of the skin- and immune cells. Two spatially distinct populations of keratinocyte stem cells (SCs) maintain the epidermal barrier function and the hair follicle. These SCs are inherently long-lived, but cell death can occur within their niches and impacts their functionality. The default cell death programme in skin is apoptosis, an orderly and non-inflammatory suicide programme. However, recent findings are shedding light on the significance of various modes of regulated necrotic cell death, which are lytic and can provoke inflammation within the local skin environment. While the presence of dying cells was generally regarded as a mere consequence of inflammation, findings in various human dermatological conditions and experimental mouse models of aberrant cell death control demonstrated that cell death programmes in keratinocytes (KCs) can drive skin inflammation and even tumour initiation. When cells die, they need to be removed by phagocytosis and KCs can function as non-professional phagocytes of apoptotic cells with important implications for their SC capacities. It is becoming apparent that in conditions of heightened SC activity, distinct cell death modalities differentially impact the different skin SC populations in their local niches. Here, we describe how regulated cell death modalities functionally affect epidermal SC niches along with their relevance to injury repair, inflammatory skin disorders and cancer.

Epigenetic and proteomic signatures associate with clonal hematopoiesis expansion rate

Clonal hematopoiesis of indeterminate potential (CHIP), whereby somatic mutations in hematopoietic stem cells confer a selective advantage and drive clonal expansion, not only correlates with age but also confers increased risk of morbidity and mortality. Here, we leverage genetically predicted traits to identify factors that determine CHIP clonal expansion rate. We used the passenger-approximated clonal expansion rate method to quantify the clonal expansion rate for 4,370 individuals in the National Heart, Lung, and Blood Institute (NHLBI) Trans-Omics for Precision Medicine (TOPMed) cohort and calculated polygenic risk scores for DNA methylation aging, inflammation-related measures and circulating protein levels. Clonal expansion rate was significantly associated with both genetically predicted and measured epigenetic clocks. No associations were identified with inflammation-related lab values or diseases and CHIP expansion rate overall. A proteome-wide search identified predicted circulating levels of myeloid zinc finger 1 and anti-Müllerian hormone as associated with an increased CHIP clonal expansion rate and tissue inhibitor of metalloproteinase 1 and glycine N-methyltransferase as associated with decreased CHIP clonal expansion rate. Together, our findings identify epigenetic and proteomic patterns associated with the rate of hematopoietic clonal expansion.

Elevated plasma triglycerides increase the risk of psoriasis: a cohort and Mendelian randomization study

BACKGROUND

It is increasingly clear that triglyceride-rich lipoproteins are proinflammatory and cause low-grade systemic inflammation. However, it is currently unknown whether elevated plasma triglycerides are causally related to the development of psoriasis, a skin disorder driven by chronic inflammation.

OBJECTIVES

To determine if elevated plasma triglycerides are associated with increased risk of psoriasis in observational and Mendelian randomization analysis.

METHODS

Consecutive individuals from the Copenhagen General Population Study were included. We used plasma triglycerides (n = 108 043) and a weighted triglyceride allele score (n = 92 579) on nine known triglyceride-altering genetic variants. Genetic results were replicated in 337 159 individuals from the UK Biobank. Psoriasis was defined using the International Classification of Diseases, version 10 (ICD-10) code for hospital contact in the main analyses, and prescription of topical antipsoriatics for mild psoriasis in the sensitivity analysis.

RESULTS

During a follow-up of median (range) 9.3 (0.1-15.1) years from 2003 to 2015 through 2018, 855 (1%) individuals were diagnosed with psoriasis by ICD-10 in the observational analysis and 772 (1%) in the Mendelian randomization analysis. In the observational analysis, the multivariable adjusted hazard ratio for psoriasis by ICD-10 was 1.26 [95% confidence interval (CI) 1.15-1.39] per doubling in plasma triglycerides with a corresponding causal odds ratio of incident psoriasis of 2.10 (95% CI 1.30-3.38). Causality was confirmed from data from the UK Biobank. Results were similar but slightly attenuated when we used topical antipsoriatic prescriptions for mild psoriasis.

CONCLUSIONS

Elevated plasma triglycerides are associated with an increased risk of psoriasis in observational and Mendelian randomization analysis.

Functional Genomics in Psoriasis

Psoriasis is an autoimmune cutaneous condition that significantly impacts quality of life and represents a burden on society due to its prevalence. Genome-wide association studies (GWASs) have pinpointed several psoriasis-related risk loci, underlining the disease's complexity. Functional genomics is paramount to unveiling the role of such loci in psoriasis and disentangling its complex nature. In this review, we aim to elucidate the main findings in this field and integrate our discussion with gold-standard techniques in molecular biology-i.e., Clustered Regularly Interspaced Short Palindromic Repeats (CRISPR)-and high-throughput technologies. These tools are vital to understanding how disease risk loci affect gene expression in psoriasis, which is crucial in identifying new targets for personalized treatments in advanced precision medicine.

Cross-Phenotype GWAS Supports Shared Genetic Susceptibility to Systemic Sclerosis and Primary Biliary Cholangitis

Objective

An increased risk of primary biliary cholangitis (PBC) has been reported in patients with systemic sclerosis (SSc). Our study aims to investigate the shared genetic susceptibility between the two disorders and to define candidate causal genes using cross-phenotype GWAS meta-analysis.

Methods

We performed cross-phenotype GWAS meta-analysis and colocalization analysis for SSc and PBC. We performed both genome-wide and locus-based analysis, including tissue and pathway enrichment analyses, fine-mapping, colocalization analyses with expression quantitative trait loci (eQTL) and protein quantitative trait loci (pQTL) datasets, and phenome-wide association studies (PheWAS). Finally, we used an integrative approach to prioritize candidate causal genes from the novel loci.

Results

We detected a strong genetic correlation between SSc and PBC (rg = 0.84, p = 1.7 × 10-6). In the cross-phenotype GWAS meta-analysis, we identified 44 non-HLA loci that reached genome-wide significance (p < 5 × 10-8). Evidence of shared causal variants between SSc and PBC was found for nine loci, five of which were novel. Integrating multiple sources of evidence, we prioritized CD40, ERAP1, PLD4, SPPL3, and CCDC113 as novel candidate causal genes. The CD40 risk locus colocalized with trans-pQTLs of multiple plasma proteins involved in B cell function.

Conclusion

Our study supports a strong shared genetic susceptibility between SSc and PBC. Through cross-phenotype analyses, we have prioritized several novel candidate causal genes and pathways for these disorders.

The Role of Genetics on Psoriasis Susceptibility, Comorbidities, and Treatment Response

This review highlights advances made in psoriasis genetics, including findings from genome-wide association studies, exome-sequencing studies, and copy number variant studies. The impact of genetic variants on various comorbidities and therapeutic responses is discussed.

Exposure to Air Pollution, Genetic Susceptibility, and Psoriasis Risk in the UK

IMPORTANCE

Psoriasis is a common autoinflammatory disease influenced by complex interactions between environmental and genetic factors. The influence of long-term air pollution exposure on psoriasis remains underexplored.

OBJECTIVE

To examine the association between long-term exposure to air pollution and psoriasis and the interaction between air pollution and genetic susceptibility for incident psoriasis.

DESIGN, SETTING, AND PARTICIPANTS

This prospective cohort study used data from the UK Biobank. The analysis sample included individuals who were psoriasis free at baseline and had available data on air pollution exposure. Genetic analyses were restricted to White participants. Data were analyzed between November 1 and December 10, 2023.

EXPOSURES

Exposure to nitrogen dioxide (NO2), nitrogen oxides (NOx), fine particulate matter with a diameter less than 2.5 µm (PM2.5), and particulate matter with a diameter less than 10 µm (PM10) and genetic susceptibility for psoriasis.

MAIN OUTCOMES AND MEASURES

To ascertain the association of long-term exposure to NO2, NOx, PM2.5, and PM10 with the risk of psoriasis, a Cox proportional hazards model with time-varying air pollution exposure was used. Cox models were also used to explore the potential interplay between air pollutant exposure and genetic susceptibility for the risk of psoriasis incidence.

RESULTS

A total of 474 055 individuals were included, with a mean (SD) age of 56.54 (8.09) years and 257 686 (54.36%) female participants. There were 9186 participants (1.94%) identified as Asian or Asian British, 7542 (1.59%) as Black or Black British, and 446 637 (94.22%) as White European. During a median (IQR) follow-up of 11.91 (11.21-12.59) years, 4031 incident psoriasis events were recorded. There was a positive association between the risk of psoriasis and air pollutant exposure. For every IQR increase in PM2.5, PM10, NO2, and NOx, the hazard ratios (HRs) were 1.41 (95% CI, 1.35-1.46), 1.47 (95% CI, 1.41-1.52), 1.28 (95% CI, 1.23-1.33), and 1.19 (95% CI, 1.14-1.24), respectively. When comparing individuals in the lowest exposure quartile (Q1) with those in the highest exposure quartile (Q4), the multivariate-adjusted HRs were 2.01 (95% CI, 1.83-2.20) for PM2.5, 2.21 (95% CI, 2.02-2.43) for PM10, 1.64 (95% CI, 1.49-1.80) for NO2, and 1.34 (95% CI, 1.22-1.47) for NOx. Moreover, significant interactions between air pollution and genetic predisposition for incident psoriasis were observed. In the subset of 446 637 White individuals, the findings indicated a substantial risk of psoriasis development in participants exposed to the highest quartile of air pollution levels concomitant with high genetic risk compared with those in the lowest quartile of air pollution levels with low genetic risk (PM2.5: HR, 4.11; 95% CI, 3.46-4.90; PM10: HR, 4.29; 95% CI, 3.61-5.08; NO2: HR, 2.95; 95% CI, 2.49-3.50; NOx: HR, 2.44; 95% CI, 2.08-2.87).

CONCLUSIONS AND RELEVANCE

In this prospective cohort study of the association between air pollution and psoriasis, long-term exposure to air pollution was associated with increased psoriasis risk. There was an interaction between air pollution and genetic susceptibility on psoriasis risk.

Exploring the role of autophagy in psoriasis pathogenesis: Insights into sustained inflammation and dysfunctional keratinocyte differentiation

Psoriasis is a common and prevalent chronic papulosquamous cutaneous disorder characterized by sustained inflammation, uncontrolled keratinocyte proliferation, dysfunctional differentiation, and angiogenesis. Autophagy, an intracellular catabolic process, can be induced in response to nutrient stress. It entails the degradation of cellular constituents through the lysosomal machinery, and its association with psoriasis has been well-documented. Nevertheless, there remains a notable dearth of research concerning the involvement of autophagy in the pathogenesis of psoriasis within human skin. This review provides a comprehensive overview of autophagy in psoriasis pathogenesis, focusing on its involvement in two key pathological manifestations: sustained inflammation and uncontrolled keratinocyte proliferation and differentiation. Additionally, it discusses potential avenues for disease management.

Advance in Multi-omics Research Strategies on Cholesterol Metabolism in Psoriasis

The skin is a complex and dynamic organ where homeostasis is maintained through the intricate interplay between the immune system and metabolism, particularly cholesterol metabolism. Various factors such as cytokines, inflammatory mediators, cholesterol metabolites, and metabolic enzymes play crucial roles in facilitating these interactions. Dysregulation of this delicate balance contributes to the pathogenic pathways of inflammatory skin conditions, notably psoriasis. In this article, we provide an overview of omics biomarkers associated with psoriasis in relation to cholesterol metabolism. We explore multi-omics approaches that reveal the communication between immunometabolism and psoriatic inflammation. Additionally, we summarize the use of multi-omics strategies to uncover the complexities of multifactorial and heterogeneous inflammatory diseases. Finally, we highlight potential future perspectives related to targeted drug therapies and research areas that can advance precise medicine. This review aims to serve as a valuable resource for those investigating the role of cholesterol metabolism in psoriasis.

Transcriptomic meta-analysis characterizes molecular commonalities between psoriasis and obesity

Despite the abundance of epidemiological evidence for the high comorbid rate between psoriasis and obesity, systematic approaches to common inflammatory mechanisms have not been adequately explored. We performed a meta-analysis of publicly available RNA-sequencing datasets to unveil putative mechanisms that are postulated to exacerbate both diseases, utilizing both late-stage, disease-specific meta-analyses and consensus gene co-expression network (cWGCNA). Single-gene meta-analyses reported several common inflammatory mechanisms fostered by the perturbed expression profile of inflammatory cells. Assessment of gene overlaps between both diseases revealed significant overlaps between up- (n = 170, P value = 6.07 × 10-65) and down-regulated (n = 49, P value = 7.1 × 10-7) genes, associated with increased T cell response and activated transcription factors. Our cWGCNA approach disentangled 48 consensus modules, associated with either the differentiation of leukocytes or metabolic pathways with similar correlation signals in both diseases. Notably, all our analyses confirmed the association of the perturbed T helper (Th)17 differentiation pathway in both diseases. Our novel findings through whole transcriptomic analyses characterize the inflammatory commonalities between psoriasis and obesity implying the assessment of several expression profiles that could serve as putative comorbid disease progression biomarkers and therapeutic interventions.

A polygenic score method boosted by non-additive models

Dominance heritability in complex traits has received increasing recognition. However, most polygenic score (PGS) approaches do not incorporate non-additive effects. Here, we present GenoBoost, a flexible PGS modeling framework capable of considering both additive and non-additive effects, specifically focusing on genetic dominance. Building on statistical boosting theory, we derive provably optimal GenoBoost scores and provide its efficient implementation for analyzing large-scale cohorts. We benchmark it against seven commonly used PGS methods and demonstrate its competitive predictive performance. GenoBoost is ranked the best for four traits and second-best for three traits among twelve tested disease outcomes in UK Biobank. We reveal that GenoBoost improves prediction for autoimmune diseases by incorporating non-additive effects localized in the MHC locus and, more broadly, works best in less polygenic traits. We further demonstrate that GenoBoost can infer the mode of genetic inheritance without requiring prior knowledge. For example, GenoBoost finds non-zero genetic dominance effects for 602 of 900 selected genetic variants, resulting in 2.5% improvements in predicting psoriasis cases. Lastly, we show that GenoBoost can prioritize genetic loci with genetic dominance not previously reported in the GWAS catalog. Our results highlight the increased accuracy and biological insights from incorporating non-additive effects in PGS models.

Rare MED12L Variants Are Associated with Susceptibility to Guttate Psoriasis in the Han Chinese Population

INTRODUCTION

According to the common disease/rare variant hypothesis, it is important to study the role of rare variants in complex diseases. The association of rare variants with psoriasis has been demonstrated, but the association between rare variants and specific clinical subtypes of psoriasis has not been investigated.

METHODS

Gene-based and gene-level meta-analyses were performed on data extracted from our previous study data sets (2,483 patients with guttate psoriasis and 8,292 patients with non-guttate psoriasis) for genotyping. Then, haplotype analysis was performed for rare loss-of-function variants located in MED12L, and protein function prediction was performed for MED12L. Gene-based analysis at each stage had a moderate significance threshold (p < 0.05). A χ2 test was then conducted on the three potential genes, and the merged gene-based analysis was used to confirm the results. We also conducted association analysis and meta-analysis for functional variants located on the identified gene.

RESULTS

Through these gene-level analyses, we determined that MED12L is a guttate psoriasis susceptibility gene (p = 9.99 × 10-5), and the single-nucleotide polymorphism with the strongest association was rs199780529 (p_combine = 1 × 10-3, p_meta = 2 × 10-3).

CONCLUSIONS

In our study, a guttate psoriasis-specific subtype-associated susceptibility gene was confirmed in a Chinese Han population. These findings contribute to a better genetic understanding of different subtypes of psoriasis.

Functional Genomics and Insights into the Pathogenesis and Treatment of Psoriasis

Psoriasis is a lifelong, systemic, immune mediated inflammatory skin condition, affecting 1-3% of the world's population, with an impact on quality of life similar to diseases like cancer or diabetes. Genetics are the single largest risk factor in psoriasis, with Genome-Wide Association (GWAS) studies showing that many psoriasis risk genes lie along the IL-23/Th17 axis. Potential psoriasis risk genes determined through GWAS can be annotated and characterised using functional genomics, allowing the identification of novel drug targets and the repurposing of existing drugs. This review is focused on the IL-23/Th17 axis, providing an insight into key cell types, cytokines, and intracellular signaling pathways involved. This includes examination of currently available biological treatments, time to relapse post drug withdrawal, and rates of primary/secondary drug failure, showing the need for greater understanding of the underlying genetic mechanisms of psoriasis and how they can impact treatment. This could allow for patient stratification towards the treatment most likely to reduce the burden of disease for the longest period possible.

Adenosine 5'monophosphate-activated protein kinase activation reduces the risks of psoriasis and its comorbidities: a Mendelian randomization study in the UK Biobank

OBJECTIVE

Whether metformin and its adenosine 5'monophosphate-activated protein kinase (AMPK) activation protect from psoriasis risk is unconcluded. We investigated the effect of AMPK, a pharmacological target of metformin, on the risk of psoriasis and its comorbidities and mortality among participants in the UK Biobank (UKB).

METHODS

To avoid immortal time biases in pharmacoepidemiologic studies, Mendelian randomization was used to infer the AMPK pathway-dependent effects. The cut-off age for distinguishing early-onset/late-onset psoriasis (EOP/LOP) was set at 60 years, based on the incident psoriasis peak in UKB. A genetic instrument comprising 44 single-nucleotide polymorphisms associated with glycated haemoglobin (HbA1c), serving as a proxy for AMPK genetic risk score (negatively associated with AMPK activation), was employed as previously reported in the literature. Log-binomial models were used to estimate the effect size of AMPK regarding relative risk (RR) and 95% CI.

RESULTS

A total of 407 159 participants were analysed, including 9126 EOP and 3324 LOP. The AMPK genetic risk score was associated with a 12.4% increase in the risk of LOP in men (RR = 1.124, 95% CI: 1.022-1.236). This association was not significant for EOP or women. AMPK genetic risk score exhibited an elevated risk of ischemic heart disease (RR = 1.217, 95% CI 1.062-1.395) in male psoriasis patients.

CONCLUSIONS

AMPK activation may protect against LOPs and associated ischemic heart disease in men. A sex-specific, comorbidity-targeted intervention for psoriasis is needed.

Identifying the genetic associations among the psoriasis patients in eastern India

Psoriasis is a multifactorial genetic disorder manifested by hyperproliferation and abnormal differentiation of epidermal keratinocytes, along with the infiltration of inflammatory cells into the skin. Although ~80 genetic susceptibility variants were reported in psoriasis, many loci showed population-specific associations, warranting the need for more population-specific association studies in psoriasis. We determined the association of forty single nucleotide polymorphisms (SNPs) among 2136 psoriasis patients and normal individuals from eastern India. We investigated the expression of corresponding genes and evaluated the protein structure stability for the genes with susceptible coding variants. We found fifteen SNPs significantly associated with psoriasis, while additional three SNPs showed significant association when we classified the patients based on the presence of HLA-Cw6 allele. Epistatic interaction between HLA-Cw6 and other associated loci showed significant association with the SNPs at PSORS1 region, along with other five SNPs outside PSORS1. Three genes showed significant differential expression in psoriatic tissues compared to the adjacent normal skin tissues but were not differential when classified the patients based on their genotypes. SNP rs495337 at SPATA2 (Spermatogenesis Associated 2) showed a 1.2-fold increased risk among the HLA-Cw6 patients compared to combined samples. We found significant downregulation of SPATA2 among the patients with risk genotypes and HLA-Cw6 allele compared to the non-risk genotypes. Protein structure stability analysis showed reduced structural stability for all the mutant residues caused by the associated coding variants. Our study evaluated the genetic associations of psoriasis-susceptible variants in India and evaluated the possible functional significance of these associated variants in psoriasis.