Low TNFAIP3 expression in psoriatic skin promotes disease susceptibility and severity

Unrestrained MyD88 signaling in A20-deficient keratinocytes triggers T cell dependent Psoriatic Arthritis like disease

Polymorphisms in A20 (TNFAIP3), a negative regulator of ubiquitin-mediated immune signaling, are strongly associated with Psoriasis and PsA. The tissue-specific roles of A20 in preventing these diseases are poorly understood. As cutaneous psoriasis typically precedes PsA by several years, skin inflammation may represent a key driver of joint disease. We now find that keratinocyte-specific deletion of A20 in normally developed adult mice spontaneously triggers both psoriasiform skin and joint disease, demonstrating a crucial role for epidermal A20 in restricting PsA-like pathology. Mice with A20-deficient keratinocytes that lack T cells were protected from PsA-like disease, showing a key role for epidermally-triggered lymphocytes in driving joint inflammation. Early gene expression analysis following keratinocyte A20 deletion identified activation of MyD88 and antiviral signaling, reflecting spatial transcriptomic changes of human psoriatic epidermis. Keratinocyte-specific loss of A20 together with MyD88, but not germline disruption of interferon receptors, in vivo protected mice from skin and joint pathology. A20-deficient primary keratinocytes from both mice and Crispr-edited human cells spontaneously produced inflammatory cytokines and chemokines in vitro in a MyD88-dependent manner. A20-deficient murine keratinocytes also directly triggered IL17A-secretion from wildtype T cells. Together, our data demonstrate that keratinocyte A20 is critical for preventing T cell dependent PsA-like disease.

Single-cell RNA sequencing of circulating immune cells supports inhibition of TNFAIP3 and NFKBIA translation as psoriatic arthritis biomarkers

Objective

To identify biomarkers that distinguish psoriatic arthritis (PsA) from cutaneous psoriasis without arthritis (PsC) and healthy controls (HC) using single cell RNA sequencing (scRNA-seq).

Method

Peripheral blood mononuclear cell samples from three patients with PsA fulfilling CASPAR criteria, three patients with PsC and two HC were profiled using scRNA-seq. Differentially expressed genes (DEGs) identified through scRNA-seq were validated on classical monocytes, and CD4+ and CD8+ T cell subsets derived from an independent cohort of patients using the NanoString nCounter® platform. Protein expression was measured in CD4+ and CD8+ T cells by immunoblotting.

Results

A total of 18 immune cell population clusters were identified. Across 18 cell clusters, we identified 234 DEGs. NFKBIA and TNFAIP3 were overexpressed in PsA vs HC and PsC patients. Immunoblotting of the proteins encoded in these genes (IκBα and A20, respectively) showed higher levels in PsA CD4+ T cells compared to HC. Conversely, lower levels were observed in PsA CD8+ T cell lysates compared to HC for both proteins.

Conclusion

These results suggest that translation of TNFAIP3 and NFKBIA may be inhibited in PsA CD8+ T cells. This study provides insight into the cellular heterogeneity of PsA, showing that non-cell type specific expression of genes associated with the disease can be dysregulated through different mechanisms in distinct cell types.

Multi-omics analysis reveals novel causal pathways in psoriasis pathogenesis

BACKGROUND

To elucidate the genetic and molecular mechanisms underlying psoriasis by employing an integrative multi-omics approach, using summary-data-based Mendelian randomization (SMR) to infer causal relationships among DNA methylation, gene expression, and protein levels in relation to psoriasis risk.

METHODS

We conducted SMR analyses integrating genome-wide association study (GWAS) summary statistics with methylation quantitative trait loci (mQTL), expression quantitative trait loci (eQTL), and protein quantitative trait loci (pQTL) data. Publicly available datasets were utilized, including psoriasis GWAS data from the European Molecular Biology Laboratory-European Bioinformatics Institute and the UK Biobank. Heterogeneity in dependent instruments (HEIDI) test and colocalization analyses were performed to identify shared causal variants, and multi-omics integration was employed to construct potential regulatory pathways.

RESULTS

Our analyses identified significant causal associations between DNA methylation, gene expression, protein abundance, and psoriasis risk. We discovered two pathways involving the long non-coding RNA RP11-977G19.11 and apolipoprotein F (APOF). Methylation at sites cg26804944 and cg02705573 was negatively associated with RP11-977G19.11 expression. Reduced expression of RP11-977G19.11 was linked to increased APOF levels, which were positively associated with a higher risk of psoriasis. Methylation at sites cg00172967, cg00294382, and cg24773560 was positively associated with RP11-977G19.11 expression. Elevated expression of RP11-977G19.11 was associated with decreased APOF levels, reducing the risk of psoriasis. Colocalization analysis highlighted APOF as a key protein in psoriasis pathogenesis. Validation using skin tissue, EBV-transformed lymphocytes data and inflammation-related protein panels confirmed the associations of RP11-977G19.11 and APOF with psoriasis.

CONCLUSIONS

Our multi-omics analysis provides preliminary evidence for potential molecular mechanisms in psoriasis pathogenesis. Through the integration of GWAS and molecular QTL data, we identify candidate pathways that may be relevant to disease biology. While these findings require extensive experimental validation, they offer a framework for future investigations into the molecular basis of psoriasis.

Discovery of Novel Biomarkers with Extended Non-Coding RNA Interactor Networks from Genetic and Protein Biomarkers

Curated online interaction databases and gene ontology tools have streamlined the analysis of highly complex gene/protein networks. However, understanding of disease pathogenesis has gradually shifted from a protein-based core to complex interactive networks where non-coding RNA (ncRNA) is thought to play an essential role. As current gene ontology is based predominantly on protein-level information, there is a growing need to analyze networks with ncRNA. In this study, we propose a gene ontology workflow integrating ncRNA using the NPInter V5.0 database. To validate the proposed workflow, we analyzed our previously published curated biomarker datasets for hidden disease susceptibility processes and pharmacogenomics. Our results show a novel involvement of melanogenesis in psoriasis response to biological drugs in general. Hyperpigmentation has been previously observed in psoriasis following treatment with currently indicated biological drugs, thus calling attention to melanogenesis research as a response biomarker in psoriasis. Moreover, our proposed workflow highlights the need to critically evaluate computed ncRNA interactions within databases and a demand for gene ontology analysis of large miRNA blocks.

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.

The Complexity of Being A20: From Biological Functions to Genetic Associations

A20, encoded by TNFAIP3, is a critical negative regulator of immune activation. A20 is a ubiquitin editing enzyme with multiple domains, each of which mediates or stabilizes a key ubiquitin modification. A20 targets diverse proteins that are involved in pleiotropic immunologic pathways. The complexity of A20-mediated immunomodulation is illustrated by the varied effects of A20 deletion in different cell types and disease models. Clinically, the importance of A20 is highlighted by its extensive associations with human disease. A20 germline variants are associated with a wide range of inflammatory diseases, while somatic mutations promote development of B cell lymphomas. More recently, the discovery of A20 haploinsufficiency (HA20) has provided real world evidence for the role of A20 in immune cell function. Originally described as an autosomal dominant form of Behcet's disease, HA20 is now considered a complex inborn error of immunity with a broad spectrum of immunologic and clinical phenotypes.

Association between several immune response-related genes and the effectiveness of biological treatments in patients with moderate-to-severe psoriasis

Biological therapies are safer and more effective against psoriasis than conventional treatments. Even so, 30-50% of psoriatic patients show an inadequate response, which is associated with individual genetic heterogeneity. Pharmacogenetic studies have identified several single nucleotide polymorphisms (SNPs) as possible predictive and prognostic biomarkers for psoriasis treatment response. The objective of this study was to determine the link between several SNPs and the clinical response to biological therapies in patients with moderate-severe psoriasis. A set of 21 SNPs related to psoriasis and/or other immunological diseases were selected and analysed from salivary samples of patients (n = 88). Treatment effectiveness and patient improvement was assessed clinically through Relative Psoriasis Area and Severity Index (PASI), also called 'PASI response', as well as absolute PASI. Associations between SNPs and PASI factors were assessed at 3 and 12 months for every treatment category of IL-17, IL-23, IL-12&23 and TNF-α inhibitors. Multivariate correlation analysis and Fisher's exact test were used to analyse the relationship between SNPs and therapy outcomes. Several SNPs located in the TLR2, TLR5, TIRAP, HLA-C, IL12B, SLC12A8, TNFAIP3 and PGLYRP4 genes demonstrated association with increased short and long-term therapy-effectiveness rates. Most patients achieved values of PASI response ≥75 or absolute PASI<1, regardless of the biological treatment administered. In conclusion, we demonstrate a relationship between different SNPs and both short- and especially long-term effectiveness of biological treatment in terms of PASI. These polymorphisms may be used as predictive markers of treatment response in patients with moderate-to-severe psoriasis, providing personalized treatment.

Diosmin nanocrystal gel alleviates imiquimod-induced psoriasis in rats via modulating TLR7,8/NF-κB/micro RNA-31, AKT/mTOR/P70S6K milieu, and Tregs/Th17 balance

Diosmin is a flavonoid with promising anti-inflammatory and antioxidant properties. However, it has difficult physicochemical characteristics since its solubility demands a pH level of 12, which has an impact on the drug's bioavailability. The aim of this work is the development and characterization of diosmin nanocrystals using anti-solvent precipitation technique to be used for topical treatment of psoriasis. Results revealed that diosmin nanocrystals stabilized with hydroxypropyl methylcellulose (HPMC E15) in ratio (diosmin:polymer; 1:1) reached the desired particle size (276.9 ± 16.49 nm); provided promising colloidal properties and possessed high drug release profile. Additionally, in-vivo assessment was carried out to evaluate and compare the activities of diosmin nanocrystal gel using three different doses and diosmin powder gel in alleviating imiquimod-induced psoriasis in rats and investigating their possible anti-inflammatory mechanisms. Herein, 125 mg of 5% imiquimod cream (IMQ) was applied topically for 5 consecutive days on the shaved backs of rats to induce psoriasis. Diosmin nanocrystal gel especially in the highest dose used offered the best anti-inflammatory effect. This was confirmed by causing the most statistically significant reduction in the psoriasis area severity index (PASI) score and the serum inflammatory cytokines levels. Furthermore, it was capable of maintaining the balance between T helper (Th17) and T regulatory (Treg) cells. Moreover, it tackled TLR7/8/NF-κB, miRNA-31, AKT/mTOR/P70S6K and elevated the TNFAIP3/A20 (a negative regulator of NF-κB) expression in psoriatic skin tissues. This highlights the role of diosmin nanocrystal gel in tackling imiquimod-induced psoriasis in rats, and thus it could be a novel promising therapy for psoriasis.

Chromatin accessibility and transcriptome integrative analysis revealed AP-1-mediated genes potentially modulate histopathology features in psoriasis

Background

Psoriasis is a chronic and hyperproliferative skin disease featured by hyperkeratosis with parakeratosis, Munro micro-abscess, elongation of rete pegs, granulosa thinning, and lymphocyte infiltration. We previously profiled gene expression and chromatin accessibility of psoriatic skins by transcriptome sequencing and ATAC-seq. However, integrating both of these datasets to unravel gene expression regulation is lacking. Here, we integrated transcriptome and ATAC-seq of the same psoriatic and normal skin tissues, trying to leverage the potential role of chromatin accessibility and their function in histopathology features.

Results

By inducing binding and expression target analysis (BETA) algorithms, we explored the target prediction of transcription factors binding in 15 psoriatic and 19 control skins. BETA identified 408 upregulated genes (rank product < 0.01) and 133 downregulated genes linked with chromatin accessibility. We noticed that cumulative fraction of genes in upregulation group was statistically higher than background, while that of genes in downregulation group was not significant. KEGG pathway analysis showed that the upregulated 408 genes were enriched in TNF, NOD, and IL-17 signaling pathways. In addition, the motif module in BETA suggested the 57 upregulated genes are targeted by transcription factor AP-1, indicating that increased chromatin accessibility facilitated the binding of AP-1 to the target regions and further induced expression of relevant genes. Among these genes, SQLE, STRN, EIF4, and MYO1B expression was increased in patients with hyperkeratosis, parakeratosis, and acanthosis thickening.

Conclusions

In summary, with the advantage of BETA, we identified a series of genes that contribute to the disease pathogenesis, especially in modulating histopathology features, providing us with new clues in treating psoriasis.

RNA-seq reveal RNA binding protein GNL3 as a key mediator in the development of psoriasis vulgaris by regulating the IL23/IL17 axis

BACKGROUND

Psoriasis is a systemic chronic inflammatory skin disorder that was prone to recurrence. The RNA binding protein GNL3 has an important function in maintaining the proliferative ability of stem cells, and its overexpression leads to apoptosis. GNL3 is expressed in the epidermis, however, its regulatory mechanism in psoriasis vulgaris is still poorly understood.

OBJECTIVE

To identify the role of GNL3 in the pathogenesis of psoriasis vulgaris.

MATERIALS AND METHODS

RNA-seq was performed to obtain the data of genes' expression and splicing events in Hela cells after shGNL3 and shCtrl was transferred. High quality results of differentially expressed genes (DEGs) and alternative splicing events (ASEs) were further attained by quality control and analysis. Through the functional enrichment analysis of DEGs and ASEs, the regulating effect of GNL3 was discussed, and the hypothesis was further confirmed in HaCat cells and psoriasis lesions.

RESULTS

The mRNA expression of IL23A in Hela cells was upregulated in GNL3 knockdown, and the ratio of ASE occurred in TNFAIP3 was increased. However, in HaCaT cells, the mRNA expression level of IL23A was downregulated in GNL3 knockdown, and the ratio of ASE of TNFAIP3 was decreased. Additionally, the results obtained in HaCaT cells was further validated in the lesional psoriatic skin.

CONCLUSION

GNL3 takes an important part in the development of psoriasis vulgaris by regulating the IL23/IL17 axis, which may serve as the basis of effective targeted treatment in future.

Staphylococcus cohnii is a potentially biotherapeutic skin commensal alleviating skin inflammation

Host-microbe interactions orchestrate skin homeostasis, the dysregulation of which has been implicated in chronic inflammatory conditions such as atopic dermatitis and psoriasis. Here, we show that Staphylococcus cohnii is a skin commensal capable of beneficially inhibiting skin inflammation. We find that Tmem79^-/- mice spontaneously develop interleukin-17 (IL-17)-producing T-cell-driven skin inflammation. Comparative skin microbiome analysis reveals that the disease activity index is negatively associated with S. cohnii. Inoculation with S. cohnii strains isolated from either mouse or human skin microbiota significantly prevents and ameliorates dermatitis in Tmem79^-/- mice without affecting pathobiont burden. S. cohnii colonization is accompanied by activation of host glucocorticoid-related pathways and induction of anti-inflammatory genes in the skin and is therefore effective at suppressing inflammation in diverse pathobiont-independent dermatitis models, including chemically induced, type 17, and type 2 immune-driven models. As such, S. cohnii strains have great potential as effective live biotherapeutics for skin inflammation.

Receptor-interacting protein kinase 1 (RIPK1) as a therapeutic target

Receptor-interacting serine/threonine-protein kinase 1 (RIPK1) is a key mediator of cell death and inflammation. The unique hydrophobic pocket in the allosteric regulatory domain of RIPK1 has enabled the development of highly selective small-molecule inhibitors of its kinase activity, which have demonstrated safety in preclinical models and clinical trials. Potential applications of these RIPK1 inhibitors for the treatment of monogenic and polygenic autoimmune, inflammatory, neurodegenerative, ischaemic and acute conditions, such as sepsis, are emerging. This article reviews RIPK1 biology and disease-associated mutations in RIPK1 signalling pathways, highlighting clinical trials of RIPK1 inhibitors and potential strategies to mitigate development challenges.

Receptor-interacting serine/threonine-protein kinase 1 (RIPK1) — a key mediator of cell death and inflammation — is activated in human diseases. Here, Yuan and colleagues discuss current understanding of RIPK1 biology and its association with diseases including inflammatory and autoimmune disorders, neurodegenerative diseases and sepsis. The clinical development of small-molecule RIPK1 inhibitors and associated challenges are discussed.

Immune Regulation of TNFAIP3 in Psoriasis through Its Association with Th1 and Th17 Cell Differentiation and p38 Activation

Background

Psoriasis is an immune-mediated chronic inflammatory skin disorder in which the dysregulation of immune cells plays an important role in its development. Tumor necrosis factor- (TNF-) α antagonists affect the immune repertoire, while TNF-α-induced protein 3 (TNFAIP3) has a protective role against the deleterious effects of inflammation and participates in immune regulation.

Objective

We investigated the immune regulation of TNFAIP3 in the pathogenesis of psoriasis and determined whether it is involved in the antipsoriatic effect of TNF-α antagonists.

Methods

mRNA levels were evaluated in blood from patients with moderate-to-severe psoriasis. The effects of TNF-α antagonists were examined in a mouse imiquimod- (IMQ-) induced psoriasis-like dermatitis model. In the mouse model, TNFAIP3 mRNA expression was determined using RT-PCR. Serum levels of IL-17A, IL-23, IFN-γ, TNF-α, phosphorylated ERK1/2, p38, and JNK were measured using ELISA. The proportion of Th1 and Th17 cells in mouse spleens was analyzed using flow cytometry.

Results

mRNA expression levels of TNFAIP3 in the blood were significantly lower in patients with moderate and severe psoriasis (mean ± SD = 0.44 ± 0.25) compared with normal subjects (mean ± SD = 1.00 ± 0.82) (P < 0.01). In the mouse model, IMQ downregulated TNFAIP3 expression levels, which were increased after TNF-α antagonist treatment (P < 0.05). Serum levels of Th17 cytokines (IL-17A and IL-23) and Th1 cytokines (IFN-γ and TNF-α) were significantly higher in the IMQ and IMQ/rat IgG1 groups compared with the control group, and the application of TNF-α antagonists significantly decreased the levels of inflammatory cytokines (P < 0.01). Notably, phosphorylated p38 levels were increased in the IMQ and IMQ/rat IgG1 groups compared with the control group but were downregulated by treatment with TNF-α antagonists (P < 0.05). Th1 and Th17 cells were significantly increased in the IMQ group compared with the control group (P < 0.01).

Conclusion

TNFAIP3 downregulation associated with Th1 and Th17 cell differentiation and p38 activation might contribute in part to the mechanism of immune dysfunction in psoriasis. TNF-α antagonists might partly exert their effects on psoriasis via this pathway.

mRNA level of ROCK1, RHOA, and LIMK2 as genes associated with apoptosis in evaluation of effectiveness of adalimumab treatment

BACKGROUND

Psoriasis is a multifactorial autoimmune disease, which underlies the abnormalities of the apoptotic process. In cases of psoriasis and psoriatic arthritis, biological treatment is used. This study aimed to determine any changes in the expression of the genes associated with apoptosis in patients with psoriatic arthritis treated with adalimumab and to assess any phenotypic modifications based on changes in dermatological indexes.

METHODS

The study included 20 patients with psoriatic arthritis treated biologically and 20 healthy volunteers. The research material consisted of peripheral blood mononuclear cells (PBMCs) from which the total RNA was isolated. Changes in the gene expression were determined using oligonucleotide microarrays and RT-qPCR. The clinical condition was assessed based on selected indicators: PASI, BSA [%], DAS28, and DLQI, which were determined every 3 months.

RESULTS

There were changes in the expression of genes associated with apoptosis. Significant differences were found for ROCK1, RhoA, and LIMK2 expression profiles in PBMCs. At the initial stage of treatment, a decrease in the PASI and BSA rates was observed. At the later stages, the values of these indicators increased once again. There were correlations between the changes in these genes' expression and the dermatological markers.

CONCLUSION

Adalimumab influences the expression of genes related to apoptosis and the values of dermatological indicators of patients. Changes in the expression level of genes associated with apoptosis suggest that ROCK1, RhoA, and LIMK2 may be genes that can potentially be indicators of treatment effectiveness and lack of response to biological treatment.