The pathological role of Wnt5a in psoriasis and psoriatic arthritis

Momordin Ic ameliorates psoriasis skin damage in mice via the IL-23/IL-17 axis

Psoriasis, a chronic and easily recurring inflammatory skin disease, causes a great economic burden to the patient's family because the etiology and mechanism are still unclear and the treatment cycle is long. In this study, the function and related mechanisms of Momordin Ic in psoriasis were investigated. The IMQ-induced mouse psoriasis model was constructed. The protective effects of different doses of Momordin Ic on psoriasis skin damage in mice were detected by PASI score, HE staining and Ki-67 staining. A psoriasis-like keratinocyte model was established at the cellular level using M5 (IL-17A, IL-22, oncostatin M, IL-1α, and TNF-α) triggered HaCaT. The effects of Momordin Ic upon HaCaT cell biological behavior were examined using MTT and CCK-8 assays. In terms of mechanism, the expression level of each inflammatory factor was assessed using IHC staining and/or ELISA, qRT-PCR, the expression of oxidative stress-related indicators was detected biochemically, and western blot was performed to detect the levels of key proteins of the Wnt signaling and VEGF. As the results shown,  at the in vivo level, Momordin Ic significantly alleviated skin damage, reduced PASI score and inhibited hyperproliferation of keratinized cells in psoriasis mice. At the cellular level, Momordin Ic also significantly reversed M5-induced hyperproliferation of HaCaT keratinocytes. In terms of mechanism, Momordin Ic significantly inhibited the IL-23/IL-17 axis, dramatically elevated the levels of intracellular antioxidants including SOD, GSH-Px, and CAT, and significantly down-regulated the levels of the indicator of oxidative damage, malondialdehyde (MDA). In addition, Momordin Ic also significantly inhibited the level of β-catenin, a pivotal protein of the Wnt signaling, C-Myc, a target gene of the Wnt signaling, and VEGF, a critical protein of angiogenesis. In conclusion, Momordin Ic can be involved in the skin-protective effects of psoriasis by multiple mechanisms, including inhibition of the Wnt signaling pathway and the IL-23/IL-17 axis, and suppression of oxidative damageand VEGF expression. Momordin Ic has been proven to be an underlying therapeutic drug for the treatment of psoriasis.

Upregulated miR-374a-5p drives psoriasis pathogenesis through WIF1 downregulation and Wnt5a/NF-κB activation

BACKGROUND

Psoriasis is a chronic, inflammatory skin disease. MicroRNAs (miRNAs) are an abundant class of non-coding RNA molecules. Recent studies have shown that multiple miRNAs are abnormally expressed in patients with psoriasis. The upregulation of miR-374a-5p has been associated with psoriasis severity. However, the specific role of miR-374a-5p in the pathogenesis of psoriasis remain unclear.

METHODS

qRT-PCR was employed to validate the expression of miR-374a-5p in psoriatic lesions and in a psoriasis-like cell model constructed using a mixture of M5 (IL-17A, IL-22, OSM, IL-1α, and TNF-α). HaCaT cells were transfected with miR-374a-5p mimic/inhibitor, and assays including EdU, CCK-8, and flow cytometry were conducted to evaluate the effect of miR-374a-5p on cell proliferation. The expression of inflammatory cytokines IL-1β, IL-6, IL-8, and TNF-α was verified by qRT-PCR. Bioinformatics analysis and dual-luciferase reporter gene assay were performed to detect the downstream target genes and upstream transcription factors of miR-374a-5p, followed by validation of their expression through qRT-PCR and Western blotting. A psoriasis-like mouse model was established using imiquimod cream topical application. The psoriasis area and severity index scoring, hematoxylin-eosin histology staining, and Ki67 immunohistochemistry were employed to validate the effect of miR-374a-5p on the psoriatic inflammation phenotype after intradermal injection of miR-374a-5p agomir/NC. Additionally, the expression of pathway-related molecules and inflammatory factors such as IL-1β, IL-17a, and TNF-α was verified by immunohistochemistry.

RESULTS

Upregulation of miR-374a-5p was observed in psoriatic lesions and the psoriasis-like cell model. In vitro experiments demonstrated that miR-374a-5p not only promoted the proliferation of HaCaT cells but also upregulated the expression of inflammatory cytokines, including IL-1β, IL-6, IL-8, and TNF-α. Furthermore, miR-374a-5p promoted skin inflammation and epidermal thickening in the Imiquimod-induced psoriasis-like mouse model. Mechanistic studies revealed that miR-374a-5p led to downregulation of WIF1, thereby activating the Wnt5a/NF-κB signaling pathway. The transcription factor p65 encoded by RELA, as a subunit of NF-κB, further upregulated the expression of miR-374a-5p upon activation. This positive feedback loop promoted keratinocyte proliferation and abnormal inflammation, thereby facilitating the development of psoriasis.

CONCLUSION

Our findings elucidate the role of miR-374a-5p upregulation in the pathogenesis of psoriasis through inhibition of WIF1 and activation of the Wnt5a/NF-κB pathway, providing new potential therapeutic targets for psoriasis.

Single-cell technologies in psoriasis

Psoriasis is a chronic and recurrent inflammatory skin disorder. The primary manifestation of psoriasis arises from disturbances in the cutaneous immune microenvironment, but the specific functions of the cellular components within this microenvironment remain unknown. Recent advancements in single-cell technologies have enabled the detection of multi-omics at the level of individual cells, including single-cell transcriptome, proteome, and metabolome, which have been successfully applied in studying autoimmune diseases, and other pathologies. These techniques allow the identification of heterogeneous cell clusters and their varying contributions to disease development. Considering the immunological traits of psoriasis, an in-depth exploration of immune cells and their interactions with cutaneous parenchymal cells can markedly advance our comprehension of the mechanisms underlying the onset and recurrence of psoriasis. In this comprehensive review, we present an overview of recent applications of single-cell technologies in psoriasis, aiming to improve our understanding of the underlying mechanisms of this disorder.

Targeting dendritic cell-specific TNFR2 improves skin and joint inflammation by inhibiting IL-12/ IFN-γ pathways in a mouse model of psoriatic arthritis

Psoriasis (PsO) and Psoriatic arthritis (PsA) are immune-mediated inflammatory diseases affecting the skin and joints. Approximately, 30% of patients with PsO develop PsA over time with both conditions being associated with elevated tumor necrosis factor-alpha (TNF-α) expression. TNF-α mediates its effect through two membrane receptors, TNFR1 and TNFR2. While current TNF-α-neutralizing agents, targeting both TNFR1 and TNFR2 receptors, constitute the primary treatment for psoriatic diseases, their long-term use is limited due to an increase in opportunistic infections, tuberculosis reactivation and malignancies likely attributed to TNFR1 inactivation. Recent findings suggest a pivotal role of TNFR2 in psoriatic disease, as evidenced by its amelioration in global TNFR2-knockout (TNFR2KO) mice, but not in TNFR1KO mice. The diminished disease phenotype in TNFR2KO mice is accompanied by a decrease in DC populations. However, the specific contribution of TNFR2 in dendritic cells (DCs) remains unclear. Here, utilizing a mannan-oligosaccharide (MOS)-induced PsA model, we demonstrate a significant reduction in PsA-like skin scaling and joint inflammation in dendritic cell-specific TNFR2 knockout mice (DC-TNFR2KO). Notably, MOS treatment in control mice (TNFR2 fl/fl) led to an increase in conventional type 1 dendritic cells (cDC1) population in the spleen, a response inhibited in DC-TNFR2KO mice. Furthermore, DC-TNFR2KO mice exhibited reduced levels of interleukin-12 (IL-12), a Th1 cell activator, as well as diminished Th1 cells, and interferon-gamma (IFN-γ) levels in the serum compared to controls following MOS stimulation. In summary, our study provides compelling evidence supporting the role of TNFR2 in promoting PsA-like inflammation through cDC1/Th1 activation pathways.

Review: A Contemporary, Multifaced Insight into Psoriasis Pathogenesis

Psoriasis is a chronic recurrent inflammatory autoimmune pathology with a significant genetic component and several interferences of immunological cells and their cytokines. The complex orchestration of psoriasis pathogenesis is related to the synergic effect of immune cells, polygenic alterations, autoantigens, and several other external factors. The major act of the IL-23/IL-17 axis, strongly influencing the inflammatory pattern established during the disease activity, is visible as a continuous perpetuation of the pro-inflammatory response and keratinocyte activation and proliferation, leading to the development of psoriatic lesions. Genome-wide association studies (GWASs) offer a better view of psoriasis pathogenic pathways, with approximately one-third of psoriasis's genetic impact on psoriasis development associated with the MHC region, with genetic loci located on chromosome 6. The most eloquent genetic factor of psoriasis, PSORS1, was identified in the MHC I site. Among the several factors involved in its complex etiology, dysbiosis, due to genetic or external stimulus, induces a burst of pro-inflammatory consequences; both the cutaneous and gut microbiome get involved in the psoriasis pathogenic process. Cutting-edge research studies and comprehensive insights into psoriasis pathogenesis, fostering novel genetic, epigenetic, and immunological factors, have generated a spectacular improvement over the past decades, securing the path toward a specific and targeted immunotherapeutic approach and delayed progression to inflammatory arthritis. This review aimed to offer insight into various domains that underline the pathogenesis of psoriasis and how they influence disease development and evolution. The pathogenesis mechanism of psoriasis is multifaceted and involves an interplay of cellular and humoral immunity, which affects susceptible microbiota and the genetic background. An in-depth understanding of the role of pathogenic factors forms the basis for developing novel and individualized therapeutic targets that can improve disease management.

Bony proliferations in rheumatoid arthritis, psoriatic arthritis and osteoarthritis using high-resolution peripheral quantitative computed tomography-A systematic literature review

PURPOSE

Osteoarthritis (OA), rheumatoid arthritis (RA), and psoriatic arthritis (PsA) can all lead to the formation of bony proliferations (BP). This systematic review aimed to examine the characteristics of BPs in patients with RA, PsA, OA, and healthy controls (HC) using high-resolution peripheral quantitative computed tomography (HR-pQCT). Secondarily, we examined any treatment-related effect on BP number and size.

METHODS

A systematic literature search was conducted in PubMed and Embase, and a total of 15 studies were included.

RESULTS

Seven studies demonstrated a disease-specific variation in BP location. One study showed no difference in the number of BPs between patients with PsA and OA. The number of BPs was greater in patients with PsA compared to RA in one study, and to HC in another study, while one study documented no difference in the number of BPs between patients with RA and HC. Five studies showed larger BPs in patients with PsA compared to HC, and one study larger BPs in patients with PsA compared to RA. One study showed no difference in BP size between patients with PsA and OA. Secukinumab may have a potential effect on arresting BP progression. Otherwise, no other treatment was reported to influence BP size and progression. No standard definitions or measurement techniques for BPs using HR-pQCT have been identified.

CONCLUSION

BPs showed disease-specific variations in location, size, and number. Results regarding treatment-related effects are sparse. An agreement on the definition and measurement technique for BPs using HR-pQCT is warranted for diagnostic accuracy, disease comparability, and monitoring potential.

Increased neutrophil-derived IL-17A identified in generalized pustular psoriasis

Generalized pustular psoriasis (GPP) is considered to be a distinct clinical entity from psoriasis vulgaris (PV), with different clinical and histological manifestations. The pathogenesis of GPP has not been thoroughly elucidated, especially in those patients lacking interleukin (IL)36RN. In present study, we performed RNA sequence analysis on skin lesions from 10 GPP patients (4 with and 6 without IL36RN mutation) and 10 PV patients without IL36RN mutation. Compared with PV, significantly overexpressed genes in GPP patients were enriched in IL-17 signalling pathway (MMP1, MMP3, DEFB4A and DEFB4B, etc.) and associated with neutrophil infiltration (MMP1, MMP3, ANXA and SERPINB, etc.). GPP with IL36RN mutations evidenced WNT11 upregulation and IL36RN downregulation in comparison to those GPP without IL36RN mutations. The expression of IL-17A/IL-36 in skin or serum and the origin of IL-17A in skin were also investigated. IL-17A expression in skin was significantly higher in GPP than PV patients, whereas, there were no differences in skin IL-36α/IL-36γ/IL-36RA or serum IL-17A/IL-36α/IL-36γ between GPP than PV. Besides, double immunofluorescence staining of MPO/IL-17A or CD3/IL-17A further confirmed that the majority of IL-17A in GPP skin was derived from neutrophils, but not T cells. These data emphasized the role of neutrophil-derived IL-17A in the pathogenesis of GPP with or without IL36RN mutations. Targeting neutrophil-derived IL-17A might be a promising treatment for GPP.

Identification of potential crucial genes shared in psoriasis and ulcerative colitis by machine learning and integrated bioinformatics

BACKGROUND

Mounting evidence suggest that there are an association between psoriasis and ulcerative colitis (UC), although the common pathogeneses are not fully understood. Our study aimed to find potential crucial genes in psoriasis and UC through machine learning and integrated bioinformatics.

METHODS

The overlapping differentially expressed genes (DEGs) of the datasets GSE13355 and GSE87466 were identified. Then the functional enrichment analysis was performed. The overlapping genes in LASSO, SVM-RFE and key module in WGCNA were considered as potential crucial genes. The receiver operator characteristic (ROC) curve was used to estimate their diagnostic confidence. The CIBERSORT was conducted to evaluate immune cell infiltration. Finally, the datasets GSE30999 and GSE107499 were retrieved to validate.

RESULTS

112 overlapping DEGs were identified in psoriasis and UC and the functional enrichment analysis revealed they were closely related to the inflammatory and immune response. Eight genes, including S100A9, PI3, KYNU, WNT5A, SERPINB3, CHI3L2, ARNTL2, and SLAMF7, were ultimately identified as potential crucial genes. ROC curves showed they all had high confidence in the test and validation datasets. CIBERSORT analysis indicated there was a correlation between infiltrating immune cells and potential crucial genes.

CONCLUSION

In our study, we focused on the comprehensive understanding of pathogeneses in psoriasis and UC. The identification of eight potential crucial genes may contribute to not only understanding the common mechanism, but also identifying occult UC in psoriasis patients, even serving as therapeutic targets in the future.

Single-cell analysis of psoriasis resolution demonstrates an inflammatory fibroblast state targeted by IL-23 blockade

Biologic therapies targeting the IL-23/IL-17 axis have transformed the treatment of psoriasis. However, the early mechanisms of action of these drugs remain poorly understood. Here, we perform longitudinal single-cell RNA-sequencing in affected individuals receiving IL-23 inhibitor therapy. By profiling skin at baseline, day 3 and day 14 of treatment, we demonstrate that IL-23 blockade causes marked gene expression shifts, with fibroblast and myeloid populations displaying the most extensive changes at day 3. We also identify a transient WNT5A+/IL24+ fibroblast state, which is only detectable in lesional skin. In-silico and in-vitro studies indicate that signals stemming from these WNT5A+/IL24+ fibroblasts upregulate multiple inflammatory genes in keratinocytes. Importantly, the abundance of WNT5A+/IL24+ fibroblasts is significantly reduced after treatment. This observation is validated in-silico, by deconvolution of multiple transcriptomic datasets, and experimentally, by RNA in-situ hybridization. These findings demonstrate that the evolution of inflammatory fibroblast states is a key feature of resolving psoriasis skin.

Associations of Wnt5a expression with liver injury in chronic hepatitis B virus infection

BACKGROUND

Aberrant Wnt5a expression contributes to immunity, inflammation and tissue damage. However, it remains unknown whether Wnt5a is associated with liver injury in chronic hepatitis B virus (HBV) infection. We aimed to explore the potential role of Wnt5a expression in liver injury caused by chronic HBV infection.

METHODS

Wnt5a mRNA levels in peripheral blood mononuclear cells (PBMCs) were analyzed in 31 acute-on-chronic hepatitis B liver failure (ACHBLF) patients, 82 chronic hepatitis B (CHB) patients, and 20 healthy controls using quantitative real-time polymerase chain reaction. Intrahepatic Wnt5a protein expression from 32 chronic HBV infection patients and 6 normal controls was evaluated by immunohistochemical staining.

RESULTS

Wnt5a mRNA expression was increased in CHB patients and ACHBLF patients compared to healthy controls and correlated positively with liver injury markers. Additionally, there was a significant correlation between Wnt5a mRNA expression and HBV DNA load in all patients and CHB patients but not in ACHBLF patients. Furthermore, intrahepatic Wnt5a protein expression was elevated in chronic HBV infection patients compared to that in normal controls. Moreover, chronic HBV infection patients with higher hepatic inflammatory grades had increased intrahepatic Wnt5a protein expression compared with lower hepatic inflammatory grades. In addition, the cut-off value of 12.59 for Wnt5a mRNA level was a strong indicator in predicting ACHBLF in CHB patients.

CONCLUSIONS

We found that Wnt5a expression was associated with liver injury in chronic HBV infection patients. Wnt5a might be involved in exacerbation of chronic HBV infection.

Prediction of Psoriatic Arthritis in Patients With Psoriasis Using DNA Methylation Profiles

OBJECTIVE

Psoriatic arthritis (PsA) is an immune-mediated inflammatory arthritis, associated with psoriasis, that significantly increases morbidity and mortality risk. We currently lack the means of predicting which patients with psoriasis will develop PsA, and a large number of patients remain undiagnosed. Regulation of gene expression through DNA methylation can potentially trigger and maintain PsA pathophysiological processes. We aimed to identify DNA methylation markers that can predict which patients with psoriasis will develop PsA prior to the onset of musculoskeletal symptoms.

METHODS

Genome-wide DNA methylation was assessed in blood samples from patients with psoriasis who went on to develop arthritis (converters) and patients with psoriasis who did not (biologic naive, matched for age, sex, psoriasis duration, and duration of follow-up). Methylation differences between converters and nonconverters were identified by a multivariate linear regression model including clinical covariates (age, sex, body mass index, smoking). Predictive performance of methylation markers was assessed by developing support vector machine classification models with and without the addition of clinical variables.

RESULTS

We identified a set of 36 highly relevant methylation markers (false discovery rate: adjusted P < 0.05 and a minimum change in methylation of 0.05) across 15 genes and several intergenic regions. A classification model relying on these markers identified converters and nonconverters with an area under the receiver operating characteristic curve of 0.9644.

CONCLUSION

This study shows that DNA methylation patterns at an early stage of psoriatic disease can distinguish between patients who will develop PsA from those who will not during the same follow-up.

A quantitative systems pharmacology model for certolizumab pegol treatment in moderate-to-severe psoriasis

Background

Psoriasis is a chronic immune-mediated inflammatory systemic disease with skin manifestations characterized by erythematous, scaly, itchy and/or painful plaques resulting from hyperproliferation of keratinocytes. Certolizumab pegol [CZP], a PEGylated antigen binding fragment of a humanized monoclonal antibody against TNF-alpha, is approved for the treatment of moderate-to-severe plaque psoriasis. Patients with psoriasis present clinical and molecular variability, affecting response to treatment. Herein, we utilized an in silico approach to model the effects of CZP in a virtual population (vPop) with moderate-to-severe psoriasis. Our proof-of-concept study aims to assess the performance of our model in generating a vPop and defining CZP response variability based on patient profiles.

Methods

We built a quantitative systems pharmacology (QSP) model of a clinical trial-like vPop with moderate-to-severe psoriasis treated with two dosing schemes of CZP (200 mg and 400 mg, both every two weeks for 16 weeks, starting with a loading dose of CZP 400 mg at weeks 0, 2, and 4). We applied different modelling approaches: (i) an algorithm to generate vPop according to reference population values and comorbidity frequencies in real-world populations; (ii) physiologically based pharmacokinetic (PBPK) models of CZP dosing schemes in each virtual patient; and (iii) systems biology-based models of the mechanism of action (MoA) of the drug.

Results

The combination of our different modelling approaches yielded a vPop distribution and a PBPK model that aligned with existing literature. Our systems biology and QSP models reproduced known biological and clinical activity, presenting outcomes correlating with clinical efficacy measures. We identified distinct clusters of virtual patients based on their psoriasis-related protein predicted activity when treated with CZP, which could help unravel differences in drug efficacy in diverse subpopulations. Moreover, our models revealed clusters of MoA solutions irrespective of the dosing regimen employed.

Conclusion

Our study provided patient specific QSP models that reproduced clinical and molecular efficacy features, supporting the use of computational methods as modelling strategy to explore drug response variability. This might shed light on the differences in drug efficacy in diverse subpopulations, especially useful in complex diseases such as psoriasis, through the generation of mechanistically based hypotheses.

Convergent deployment of ancestral functions during the evolution of mammalian flight membranes

Lateral flight membranes, or patagia, have evolved repeatedly in diverse mammalian lineages. While little is known about patagium development, its recurrent evolution may suggest a shared molecular basis. By combining transcriptomics, developmental experiments, and mouse transgenics, we demonstrate that lateral Wnt5a expression in the marsupial sugar glider (Petaurus breviceps) promotes the differentiation of its patagium primordium. We further show that this function of Wnt5a reprises ancestral roles in skin morphogenesis predating mammalian flight and has been convergently used during patagium evolution in eutherian bats. Moreover, we find that many genes involved in limb development have been redeployed during patagium outgrowth in both the sugar glider and bat. Together, our findings reveal that deeply conserved genetic toolkits contribute to the evolutionary transition to flight in mammals.

Non-Canonical WNT/Wnt5a Pathway Activity in Circulating Monocytes of Untreated Psoriatic Patients: An Exploratory Study of Its Association with Inflammatory Cytokines and Cardiovascular Risk Marker-ADAMTS7

The leading cause of death in psoriasis is cardiovascular disease. The determinants that induce the increase in this risk are not known. The systemic inflammatory process is dependent on lymphocytes and monocytes, as has been proposed. However, adaptation modules such as mTOR have recently been mentioned as having a role. Other factors, such as WNT and its non-canonical WNT5a-inducing pathway, are relevant in inflammation, cell migration, and neoangiogenesis. Thus, we studied circulating monocytes from untreated severe psoriatic patients and characterized inflammatory cytokines, chemokines, mTOR activity, and the cardiovascular risk marker ADAMTS7. Peripheral blood from ten severely psoriatic patients (Psoriasis severity index greater than 10) was extracted and age- and sex-matched with healthy subjects. Surface and intracellular flow cytometry were performed for cytokine, chemokine receptors, and mTOR activity. ADAMTS7 was measured using ELISA. Psoriatic patients had a higher frequency of WNT5a+ cells in monocytes, which also had higher levels of IL-1β, IL-6, CXCR3, CCR2, and phosphorylated S6R protein. We found that M1 monocytes are dominant in the WNT5a+ cell group, and intracellular levels of WNT5a were also augmented. Levels of WNT5a were correlated with ADAMTS7, a blood marker related to the pathogenesis of atheromatosis. WNT5a could be relevant to the cardiovascular risk of psoriatic patients considering its association with higher levels of inflammatory cytokines, chemokine receptors and the pro-atherogenic profile of circulating monocytes.

Single-cell RNA sequencing reveals dysregulated fibroblast subclusters in prurigo nodularis

Prurigo nodularis (PN) is an intensely pruritic, chronic inflammatory skin disease that disproportionately affects black patients. However, the pathogenesis of PN is poorly understood. We performed single-cell transcriptomic profiling, ligand receptor analysis and cell trajectory analysis of 28,695 lesional and non-lesional PN skin cells to uncover disease-identifying cell compositions and genetic characteristics. We uncovered a dysregulated role for fibroblasts (FBs) and myofibroblasts as a key pathogenic element in PN, which were significantly increased in PN lesional skin. We defined seven unique subclusters of FBs in PN skin and observed a shift of PN lesional FBs towards a cancer-associated fibroblast (CAF)-like phenotype, with WNT5A+ CAFs increased in the skin of PN patients and similarly so in squamous cell carcinoma (SCC). A multicenter PN cohort study subsequently revealed an increased risk of SCC as well as additional CAF-associated malignancies in PN patients, including breast and colorectal cancers. Systemic fibroproliferative diseases were also upregulated in PN patients, including renal sclerosis and idiopathic pulmonary fibrosis. Ligand receptor analyses demonstrated increased FB1-derived WNT5A and periostin interactions with neuronal receptors MCAM and ITGAV, suggesting a fibroblast-neuronal axis in PN. Type I IFN responses in immune cells and increased angiogenesis/permeability in endothelial cells were also observed. As compared to atopic dermatitis (AD) and psoriasis (PSO) patients, increased mesenchymal dysregulation is unique to PN with an intermediate Th2/Th17 phenotype between atopic dermatitis and psoriasis. These findings identify a pathogenic role for CAFs in PN, including a novel targetable WNT5A+ fibroblast subpopulation and CAF-associated malignancies in PN patients.

Wnt Signaling Pathways: From Inflammation to Non-Melanoma Skin Cancers

Canonical and non-canonical Wnt signaling pathways are involved in cell differentiation and homeostasis, but also in tumorigenesis. In fact, an exaggerated activation of Wnt signaling may promote tumor growth and invasion. We summarize the most intriguing evidence about the role of Wnt signaling in cutaneous carcinogenesis, in particular in the pathogenesis of non-melanoma skin cancer (NMSC). Wnt signaling is involved in several ways in the development of skin tumors: it may modulate the inflammatory tumor microenvironment, synergize with Sonic Hedgehog pathway in the onset of basal cell carcinoma, and contribute to the progression from precancerous to malignant lesions and promote the epithelial-mesenchymal transition in squamous cell carcinoma. Targeting Wnt pathways may represent an additional efficient approach in the management of patients with NMSC.

Non-canonical WNT signalling in cardiovascular disease: mechanisms and therapeutic implications

WNT signalling comprises a diverse spectrum of receptor-mediated pathways activated by a large family of WNT ligands and influencing fundamental biological processes. WNT signalling includes the β-catenin canonical pathway and the non-canonical pathways, namely the planar cell polarity and the calcium-dependent pathways. Advances over the past decade have linked non-canonical WNT signalling with key mechanisms of atherosclerosis, including oxidative stress, endothelial dysfunction, macrophage activation and vascular smooth muscle cell phenotype regulation. In addition, non-canonical WNT signalling is involved in crucial aspects of myocardial biology, from fibrosis to hypertrophy and oxidative stress. Importantly, non-canonical WNT signalling activation has complex effects in adipose tissue in the context of obesity, thereby potentially linking metabolic and vascular diseases. Tissue-specific targeting of non-canonical WNT signalling might be associated with substantial risks of off-target tumorigenesis, challenging its therapeutic potential. However, novel technologies, such as monoclonal antibodies, recombinant decoy receptors, tissue-specific gene silencing with small interfering RNAs and gene editing with CRISPR-Cas9, might enable more efficient therapeutic targeting of WNT signalling in the cardiovascular system. In this Review, we summarize the components of non-canonical WNT signalling, their links with the main mechanisms of atherosclerosis, heart failure and arrhythmias, and the rationale for targeting individual components of non-canonical WNT signalling for the treatment of cardiovascular disease.

Contribution of the Environment, Epigenetic Mechanisms and Non-Coding RNAs in Psoriasis

Despite the increasing research and clinical interest in the predisposition of psoriasis, a chronic inflammatory skin disease, the multitude of genetic and environmental factors involved in its pathogenesis remain unclear. This complexity is further exacerbated by the several cell types that are implicated in Psoriasis’s progression, including keratinocytes, melanocytes and various immune cell types. The observed interactions between the genetic substrate and the environment lead to epigenetic alterations that directly or indirectly affect gene expression. Changes in DNA methylation and histone modifications that alter DNA-binding site accessibility, as well as non-coding RNAs implicated in the post-transcriptional regulation, are mechanisms of gene transcriptional activity modification and therefore affect the pathways involved in the pathogenesis of Psoriasis. In this review, we summarize the research conducted on the environmental factors contributing to the disease onset, epigenetic modifications and non-coding RNAs exhibiting deregulation in Psoriasis, and we further categorize them based on the under-study cell types. We also assess the recent literature considering therapeutic applications targeting molecules that compromise the epigenome, as a way to suppress the inflammatory cutaneous cascade.

TNF-α Activating Osteoclasts in Patients with Psoriatic Arthritis Enhances the Recruitment of Osteoclast Precursors: A Plausible Role of WNT5A-MCP-1 in Osteoclast Engagement in Psoriatic Arthritis

Psoriatic arthritis (PsA) results from joint destruction by osteoclasts. The promising efficacy of TNF-α blockage indicates its important role in osteoclastogenesis of PsA. WNT ligands actively regulate osteoclastogenesis. We investigated how WNT ligands activate osteoclasts amid the TNF-α milieu in PsA. We first profiled the expression of WNT ligands in CD14⁺ monocyte-derived osteoclasts (MDOC) from five PsA patients and five healthy controls (HC) and then validated the candidate WNT ligands in 32 PsA patients and 16 HC. Through RNA interference against WNT ligands in MDOC, we determined the mechanisms by which TNF-α exerts its effects on osteclastogenesis or chemotaxis. WNT5A was selectively upregulated by TNF-α in MDOC from PsA patients. The number of CD68⁺WNT5A⁺ osteoclasts increased in PsA joints. CXCL1, CXCL16, and MCP-1 was selectively increased in supernatants of MDOC from PsA patients. RNA interference against WNT5A abolished the increased MCP-1 from MDOC and THP-1-cell-derived osteoclasts. The increased migration of osteoclast precursors (OCP) induced by supernatant from PsA MDOC was abolished by the MCP-1 neutralizing antibody. WNT5A and MCP-1 expressions were decreased in MDOC from PsA patients treated by biologics against TNF-α but not IL-17. We conclude that TNF-α recruits OCP by increased MCP-1 production but does not directly activate osteoclastogenesis in PsA.

The Levels of Wnt5a and Its Receptors Frizzled5 and Frizzled2 as Immunohistochemical Biomarkers of Severity of Psoriasis

Purpose

Psoriasis is a systemic, chronic and inflammatory condition. The exact pathogenesis is unclear. The abnormal expression of Wnt5a pathway in psoriasis vulgaris has been confirmed. Whether it is related to the severity of psoriasis is unclear.

Methods

Thirty-eight skin lesions from psoriasis vulgaris patients and 22 healthy adult skin tissues were taken. The semi-quantitative immunohistochemistry score of Wnt5a, Frizzled5 and Frizzled2 was evaluated under a microscope by two independent dermatologists. Psoriasis area and severity index (PASI) score system was used to evaluate the disease severity.

Results

The average PASI score of the patients was 16.25 ± 7.8, and the average duration of disease was 19.6 ± 10.4 months. Wnt5a, Frizzled5 and Frizzled2 were highly expressed in psoriasis lesions. The semi-quantitative immunohistochemistry scores of Wnt5a, Frizzled5 and Frizzled2 were positively correlated with PASI scores (r = 0.71, r = 0.46, r = 0.65, respectively, all P-value < 0.01), but not correlated with duration of disease (r = 0.11, r = 0.17, r = 0.29, respectively, all P-value > 0.05). There were significant positive correlations between Wnt5a and Frizzled5 (r = 0.57, P-value < 0.01), as well as Wnt5a and Frizzled2 (r = 0.59, P-value < 0.01).

Conclusion

Wnt5a and its receptors play an important role in pathogenesis of psoriasis vulgaris and are positively correlated with the severity of psoriasis, and may be one of the immunohistochemical predictors of the severity of the disease.

The hair follicle-psoriasis axis: Shared regulatory mechanisms and therapeutic targets

It has long been known that there is a special affinity of psoriasis for the scalp: Here, it occurs most frequently, lesions terminate sharply in frontal skin beyond the hair line and are difficult to treat. Yet, surprisingly, scalp psoriasis only rarely causes alopecia, even though the pilosebaceous unit clearly is affected. Here, we systematically explore the peculiar, insufficiently investigated connection between psoriasis and growing (anagen) terminal scalp hair follicles (HFs), with emphasis on shared regulatory mechanism and therapeutic targets. Interestingly, several drugs and stressors that can trigger/aggravate psoriasis can inhibit hair growth (e.g. beta-blockers, chloroquine, carbamazepine, interferon-alpha, perceived stress). Instead, several anti-psoriatic agents can stimulate hair growth (e.g. cyclosporine, glucocorticoids, dithranol, UV irradiation), while skin/HF trauma (Köbner phenomenon/depilation) favours the development of psoriatic lesions and induces anagen in "quiescent" (telogen) HFs. On this basis, we propose two interconnected working models: (a) the existence of a bidirectional "hair follicle-psoriasis axis," along which keratinocytes of anagen scalp HFs secrete signals that favour the development and maintenance of psoriatic scalp lesions and respond to signals from these lesions, and (b) that anagen induction and psoriatic lesions share molecular "switch-on" mechanisms, which invite pharmacological targeting, once identified. Therefore, we advocate a novel, cross-fertilizing and integrative approach to psoriasis and hair research that systematically characterizes the "HF-psoriasis axis," focused on identification and therapeutic targeting of selected, shared signalling pathways in the future management of both, psoriasis and hair growth disorders.

miR-145-5p inhibits psoriasis progression by regulating the Wnt/β-catenin pathway

OBJECTIVE

This research aimed to probe into the effect of miR-145-5p in psoriasis by regulating Wnt/β-catenin.

METHODS

A total of 45 psoriasis patients treated in our hospital were enrolled into an observation group (OG), and other 40 healthy individuals in physical examination over the same period were enrolled into a control group (CG). miR-145-5p in both groups was quantified, and its value in diagnosis and recurrence prediction of psoriasis was analyzed. Additionally, miR-145-5p was transfected into HaCat cells to analyze the biological behaviors of transfected cells, and factors for Wnt/β-catenin pathway inhibition were injected into cells to detect its protein expression in the cells, so as to verify the regulation of miR-145-5p on the Wnt/β-catenin pathway.

RESULTS

with low expression in the serum of psoriasis patients (P<0.05), miR-145-5p was of great application value for diagnosis and recurrence prediction. In the inhibition group, miR-145-5p increased (P<0.05), while Wnt/β-catenin pathway-related proteins decreased (P<0.05). Compared with untreated HaCat cells, the protein expression in HaCat cells treated with XAV-939 decreased (P<0.05). There was no notable difference between the miR-145-5p-mimics+XAV-939 group and the empty vector group in cell proliferation, apoptosis rate, and expression of Wnt3a, Wnt5a, and β-catenin proteins (all P>0.05); but compared with both groups, the miR-145-5p-mimics group showed lower proliferation activity, higher apoptosis rate, and higher expression of Wnt3a, Wnt5a, and β-catenin proteins (all P<0.05).

CONCLUSION

Up-regulating miR-145-5p can activate the Wnt β-catenin signal pathway, thus inhibiting psoriasis progression.

The pathological role of Wnt5a in psoriasis and psoriatic arthritis

Psoriasis (PsO) is a chronic inflammatory skin disease with both local and systemic components. PsO‐associated arthritis, known as psoriatic arthritis (PsA), develops in approximately 13%‐25% of PsO patients. Various factors associated with both PsO and PsA indicate that these conditions are part of a single disease. Identification of novel targets for the development of drugs to treat both PsO and PsA is desirable to provide more patient‐friendly treatment regimens. Such targets will likely represent ‘common checkpoints’ of inflammation, for example key components or transduction cascades of the signalling pathways involved. Emerging evidence supports involvement of the non‐canonical Wnt signalling pathways in the development of both PsO and PsA, especially the Wnt5a‐activated signalling cascades. These, together with interlinked factors, are crucial in the interactions among keratinocytes, immune cells and inflammatory factors in PsO, as well as among chondrocytes, osteoblasts and osteoclasts that trigger both subchondral bone remodelling and cartilage catabolism in PsA. This review focuses on the pathological role of Wnt5a signalling and its interaction with other interlinked pathways in both PsO and PsA, and also on the main challenges for future research, particularly with respect to molecules targeting Wnt signalling pathways for the treatment of PsO and PsA.