Crossing the boundaries: IL-23 and its role in linking inflammation of the skin, gut and joints

Intestinal epithelial expression of human TNF is sufficient to induce small bowel inflammation and sacroiliitis, mimicking human spondyloarthritis

OBJECTIVES

Gut and joint disease commonly co-occur in SpA. Up to 50% of patients with SpA show signs of subclinical gut inflammation, of which 10% develops IBD. However, the mechanisms underlying this gut-joint axis are still unclear. Here we investigated the hypothesis that restricted expression of a pro-inflammatory cytokine in the intestine may trigger the onset of combined gut and joint inflammation.

METHODS

Intestinal expression of human TNF (hTNF) was achieved by driving hTNF gene expression using the rat FAPB2 promoter, creating a new animal model, TNFgut mice, that expresses hTNF in the proximal intestinal tract. Intestinal-specific TNFgut mice were examined for pathological changes in the intestine and extra-intestinal tissues by means of histology, reverse transcription PCR (RT-PCR) and flow cytometry, along with 16S sequencing on stools.

RESULTS

Local expression of hTNF in the epithelium of the small intestine induces a pro-inflammatory state of the proximal intestinal tract, with epithelial alterations and induction of members of the S100 family, as well as local upregulation of Th17 and Treg, but no obvious signs of dysbiosis. Curiously, TNFgut mice develop sacroiliitis (P <0.05) in addition to small bowel inflammation (P <0.05). However, no signs of peripheral arthritis or enthesitis could be documented.

CONCLUSION

Intestinal expression of hTNF is sufficient to initiate a pro-inflammatory cascade culminating in small bowel inflammation and sacroiliitis. Thus, gut-derived cytokines are sufficient to induce SpA.

Guselkumab binding to CD64+ IL-23-producing myeloid cells enhances potency for neutralizing IL-23 signaling

IL-23 is implicated in the pathogenesis of immune-mediated inflammatory diseases, and myeloid cells that express Fc gamma receptor 1 (FcγRI or CD64) on their surface have been recently identified as a primary source of IL-23 in inflamed tissue. Our complementary analyses of transcriptomic datasets from psoriasis and IBD showed increased expression of CD64 and IL-23 transcripts in inflamed tissue, and greater abundance of cell types with co-expression of CD64 and IL-23. These findings led us to explore potential implications of CD64 binding on the function of IL-23-targeting monoclonal antibodies (mAbs). Guselkumab and risankizumab are mAbs that target the IL-23p19 subunit. Guselkumab has a native Fc domain while risankizumab contains mutations that diminish binding to FcγRs. In flow cytometry assays, guselkumab, but not risankizumab, showed Fc-mediated binding to CD64 on IFNγ-primed monocytes. Guselkumab bound CD64 on IL-23-producing inflammatory monocytes and simultaneously captured IL-23 secreted from these cells. Guselkumab binding to CD64 did not induce cytokine production. In live-cell confocal imaging of CD64+ macrophages, guselkumab, but not risankizumab, mediated IL-23 internalization to low-pH intracellular compartments. Guselkumab and risankizumab demonstrated similar potency for inhibition of IL-23 signaling in cellular assays with exogenous addition of IL-23. However, in a co-culture of IL-23-producing CD64+ THP-1 cells with an IL-23-responsive reporter cell line, guselkumab demonstrated Fc-dependent enhanced potency compared to risankizumab for inhibiting IL-23 signaling. These in vitro data highlight the potential for guselkumab binding to CD64 in inflamed tissue to contribute to the potent neutralization of IL-23 at its cellular source.

IL-23R is a senescence-linked circulating and tissue biomarker of aging

Cellular senescence is an aging mechanism characterized by cell cycle arrest and a senescence-associated secretory phenotype (SASP). Preclinical studies demonstrate that senolytic drugs, which target survival pathways in senescent cells, can counteract age-associated conditions that span several organs. The comparative efficacy of distinct senolytic drugs for modifying aging and senescence biomarkers in vivo has not been demonstrated. Here, we established aging- and senescence-related plasma proteins and tissue transcripts that changed in old versus young female and male mice. We investigated responsivity to acute treatment with venetoclax, navitoclax, fisetin or luteolin versus transgenic senescent cell clearance in aged p16-InkAttac mice. We discovered that age-dependent changes in plasma proteins, including IL-23R, CCL5 and CA13, were reversed by senotherapeutics, which corresponded to expression differences in tissues, particularly in the kidney. In plasma from humans across the lifespan, IL-23R increased with age. Our results reveal circulating factors as candidate mediators of senescence-associated interorgan signal transduction and translationally impactful biomarkers of systemic senescent cell burden.

Efficacy and retention rate of secukinumab in psoriatic arthritis across different clinical phenotypes: insights from the Italian GISEA Registry

Background

Randomized clinical trials have demonstrated the efficacy of secukinumab (SECU) in reducing disease activity in psoriatic arthritis (PsA), while real-world studies prove a broader perspective on SECU's usefulness in everyday clinical practice.

Objectives

To assess the effectiveness of SECU by evaluating drug survival and identifying potential predictors of clinical response and treatment discontinuation in patients with moderate-to-severe PsA, using real-world data from the Italian Group for the Study of Early Arthritis (GISEA) registry.

Design

This longitudinal retrospective study included PsA patients treated with SECU, spanning from May 2016 to November 2023.

Methods

Data from 1045 PsA patients, including 783 with peripheral-only PsA (perPsA) and 262 with peripheral and axial involvement (mixed PsA) were analyzed. Drug survival was estimated by Kaplan-Meier analysis. Clinical outcomes, including Disease Activity Index for Psoriatic Arthritis (DAPSA), Psoriasis Area Severity Index (PASI), Ankylosing Spondylitis Disease Activity Score (ASDAS, C-Reactive Protein (CRP)-based), and Visual Analogue Scale (VAS) measures, were evaluated at baseline and at 6, 12, and 24 months. Adjusted hazard ratios (aHRs) for discontinuing SECU were determined using multivariate Cox regression models.

Results

SECU survival at 24 months was 63.24%, significantly higher in mixed PsA compared to perPsA (p = 0.036). In the overall PsA population, DAPSA scores decreased significantly at 6 months, and further at 24 months (all p < 0.0001). In mixed PsA, ASDAS-CRP scores were significantly reduced at 6 months and remained stable through 24 months (all p < 0.0001). VAS pain scores also improved already at 6 months and continued to improve at 24 months (all p < 0.0001). Higher age (aHR = 0.98, 95% confidence interval (CI): 0.96-0.99, p = 0.007) and lower baseline DAPSA scores (aHR = 1.02, 95% CI: 1.01-1.03, p = 0.014) were associated with greater persistence of SECU treatment. SECU was well tolerated, with no serious adverse events.

Conclusion

SECU showed sustained clinical improvements in both peripheral and axial involvement of PsA patients over 24 months, with higher persistence observed in mixed PsA patients. Our findings highlight the favorable clinical and safety profile of SECU in real world.

Treatment controversies in spondyloarthritis and psoriatic arthritis: focus on biologics and targeted therapies

INTRODUCTION

There are several treatment controversies that have emerged in spondyloarthritis and psoriatic arthritis. These are related to the nature of the conditions as well as to the use of medications.

AREAS COVERED

This review, which included a search of PubMed database as well as the references within the articles provides an overview of the nature of spondyloarthritis, controversy over the inclusion of psoriatic arthritis (PsA) as a peripheral spondyloarthritis, and a summary of current treatments for both PsA and axial spondyloarthritis (axSpA), with special emphasis on targeted therapy. The review highlights the differences in response to certain medications, particularly biologic therapy and summarizes the randomized controlled trials in psoriatic arthritis and axial spondyloarthritis providing data about the responses in table format.

EXPERT OPINION

There is a need for better outcome measures in axSpA. Currently, the measures are subjective. Imaging may be more appropriate but there is a need for research into the reliability and responsiveness of imaging techniques. In PsA, there may also be better response measures and research into the reliability and responsiveness of available measures is underway. There is also a need for novel therapies as well as biomarkers for response in both diseases.

GSK805 inhibits alpha-smooth muscle expression and modulates liver inflammation without impairing the well-being of mice

Cholestatic liver diseases, such as primary biliary cholangitis (PBC) and primary sclerosing cholangitis (PSC), lead to inflammation and severe hepatic damage with limited therapeutic options. This study assessed the efficacy of the inverse RORγt agonist, GSK805, both in vitro using the hepatic stellate cell-line LX-2 and in vivo using male bile duct-ligated BALB/c mice. In vitro, 0.3 μM GSK805 reduced alpha-smooth muscle actin expression in LX-2 cells. In vivo, GSK805 significantly decreased IL-23R, TNF-α, and IFN-γ expression in cholestatic liver. Despite high concentrations of GSK805 in the liver, no significant reduction in fibrosis was noticed. GSK805 significantly increased aspartate aminotransferase and alanine aminotransferase activity in the blood, while levels of glutamate dehydrogenase, alkaline phosphatase, and bilirubin were not substantially increased. Importantly, GSK805 did neither increase an animal distress score nor substantially reduce body weight, burrowing activity, or nesting behavior. These results suggest that a high liver concentration of GSK805 is achieved by daily oral administration and that this drug modulates inflammation in cholestatic mice without impairing animal well-being.

[Old and New Biologics and Small Molecules in Inflammatory Bowel Disease: Anti-interleukins]

Inflammatory bowel disease (IBD), including Crohn's disease and ulcerative colitis, is a chronic inflammatory disease of the gastrointestinal tract. The introduction of biologics, particularly anti-interleukin (IL) agents, has revolutionized IBD treatment. This review summarizes the role of ILs in IBD pathophysiology and describes the efficacy and positioning of anti-IL therapies. We discuss the functions of key ILs in IBD and their potential as therapeutic targets. The review then discusses anti-IL therapies, focusing primarily on ustekinumab (anti-IL-12/23), risankizumab (anti-IL-23), and mirikizumab (anti-IL-23). Clinical trial data demonstrate their efficacy in inducing and maintaining remission in Crohn's disease and ulcerative colitis. The safety profiles of these agents are generally favorable. However, long-term safety data for newer agents are still limited. The review also briefly discusses emerging therapies such as guselkumab and brazikumab. Network meta-analyses suggest that anti-IL therapies perform well compared to other biological agents. These agents may be considered first- or second-line therapies for many patients, especially those with comorbidities or safety concerns. Anti-IL therapies represent a significant advancement in IBD treatment, offering effective and relatively safe options for patients with moderate to severe disease.

Serum concentrations of 25-OH vitamin D and the pro-inflammatory interleukins IL-17, IL-23, and IL-18 in patients with plaque psoriasis

AIMS

The present study aimed to assess vitamin D status and serum concentrations of pro-inflammatory cytokines IL-17, Il-23, and IL-18 in patients with chronic plaque psoriasis and their association with various demographic and clinical characteristics.

METHODS

The study was conducted during the autumn/winter period on 48 patients with chronic plaque psoriasis and 48 controls. Total serum 25(OH)D level was determined with Roche Elecsys® 2010 Vitamin D total assay. Commercial ELISA kits were used for quantifying the serum levels of IL-17A, IL-18, and IL-23.

RESULTS

Serum 25(OH)D had a median value of 16.95 ng/mL (IQR 10.8-23.50) for patients with psoriasis and 18.80 ng/mL (IQR 15.45-25.85) for the control group (P=0.09). A moderate negative correlation was found between PASI score and 25(OH)D levels (rs=-0.34; P=0.02). The serum levels of IL-17 (P=0.001), IL-23 (P=0.01) and IL-18 (P=0.02) were significantly higher in the patient group compared to controls. IL-17 concentrations were higher in patients with moderate to severe psoriasis compared to patients with mild psoriasis (P=0.003). No significant correlations were detected between the serum concentrations of 25(ОH)D and IL-17, IL-23, and IL-18.

CONCLUSION

It was confirmed that IL-17 serum level is associated with psoriasis severity. Measurement of 25(OH)D serum concentration can be useful in patients with moderate to severe psoriasis with or without comorbidities. A direct association between 25(OH)D serum concentration and the serum concentrations of IL-17, IL-23, or IL-18 was not identified in this study.

Elevated type-17 cytokines are present in axial spondyloarthritis stool

Axial spondyloarthritis (axSpA) is characterized by type-17 immune-driven joint inflammation, and intestinal inflammation is present in around 70% of patients. In this study, we asked whether axSpA stool contained Th17-associated cytokines and whether this related to systemic Th17 activation. We measured stool cytokine and calprotectin levels by ELISA and found that patients with axSpA have increased stool IL-17A, IL-23, GM-CSF, and calprotectin. We further identified increased levels of circulating IL-17A+ and IL-17F+ T-helper cell lymphocytes in patients with axSpA compared to healthy donors. We finally assessed stool metabolites by unbiased nuclear magnetic resonance spectroscopy and found that multiple stool amino acids were negatively correlated with stool IL-23 concentrations. These data provide evidence of type-17 immunity in the intestinal lumen, and suggest its association with microbial metabolism in the intestine.

IL-23 past, present, and future: a roadmap to advancing IL-23 science and therapy

Interleukin (IL)-23, an IL-12 cytokine family member, is a hierarchically dominant regulatory cytokine in a cluster of immune-mediated inflammatory diseases (IMIDs), including psoriasis, psoriatic arthritis, and inflammatory bowel disease. We review IL-23 biology, IL-23 signaling in IMIDs, and the effect of IL-23 inhibition in treating these diseases. We propose studies to advance IL-23 biology and unravel differences in response to anti-IL-23 therapy. Experimental evidence generated from these investigations could establish a novel molecular ontology centered around IL-23-driven diseases, improve upon current approaches to treating IMIDs with IL-23 inhibition, and ultimately facilitate optimal identification of patients and, thereby, outcomes.

A standardized wound infection model for antimicrobial testing of wound dressings in vitro

To investigate the effectiveness of antimicrobial agents against wound infections, experiments using either 2D cultures with planktonic microorganisms or animal infection models are frequently carried out. However, the transferability of the results to human skin is limited by the lack of complexity of the 2D models or by the poor translation of the results from animal models. Hence, there is a need for wound infection models capable of assessing antimicrobial agents. In this study, an easily standardized wound infection model was established. This model consists of a mechanically wounded human skin model on a collagen matrix infected with various clinically relevant bacteria. Infection of the model led to recognition of the pathogens and induction of an inflammatory response. The untreated infection spread over time, causing significant tissue damage. By applying an antimicrobial-releasing wound dressing, the bacterial load could be reduced and the success of the treatment could be further measured by a decrease in the inflammatory reaction. In conclusion, this wound infection model can be used to evaluate new antimicrobial therapeutics as well as to study host-pathogen interactions.

Psoriasis, bone and bowel: a comprehensive review and new insights

Psoriasis is a chronic immune-mediated disorder affecting about 2% of the population worldwide which is associated with significant morbidity. The disease usually presents as raised, well-demarcated erythematous plaques with adherent silvery scales. Psoriasis can appear at any age but it has two peaks occurring at 15–20 and 55–60 years of age. It affects males and females equally. Despite the multitude of investigations about psoriasis and even development of drugs with satisfactory results, its pathogenesis is not fully understood yet and its course is unpredictable. Various environmental triggers, e.g., obesity, stress and drugs may induce disease in genetically susceptible patients. Although psoriasis was considered primarily as a disease of the skin, more investigations have been revealed its systemic nature. Psoriatic arthritis (PsA) may complicate up to one-third of cases of psoriasis vulgaris (PV). Also, the association between psoriasis and a variety of other immune-mediated disorders such as inflammatory bowel disease (IBD) and celiac disease (CD) has been confirmed in various studies. Moreover, a growing body of evidences indicates that psoriasis shares some common histological and phenotypical properties with the spectrum of osteoimmunological diseases such as Paget’s disease of bone (PDB). Thus, exploring the common molecular and genetic mechanisms underlying psoriasis and related disorders is of paramount importance for better elucidating disease pathogenesis and designing more targeted treatments.

Successful treatment of refractory enteritis and arthritis with combination of tumour necrosis factor and interleukin-6 inhibition in patients with ulcerative colitis

An 18 year-old man with autoimmune hepatitis-primary sclerosing cholangitis-overlap syndrome and ulcerative colitis was admitted due to relapsed enteritis and polyarthritis after cessation of infliximab. Colonoscopy and articular ultrasonography revealed large ulcers in the colon with crypt abscess in the specimens and active enthesitis and synovitis, respectively. His intestinitis was improved with golimumab but arthritis was persistent. Golimumab was switched to secukinumab, which was effective for arthritis. However, colitis was flared resulting in total colorectal resection. One month after colectomy, polyarthritis was relapsed. Tocilizumab ameliorated arthritis but enteritis emerged again, and switching tocilizumab to adalimumab improved enteritis but arthritis exacerbated. Finally, we restarted tocilizumab for arthritis with continued adalimumab for enteritis. The dual cytokine blocking strategy, tumour necrosis factor-α and interleukin-6 inhibition, subsided both of his refractory enteritis and arthritis and maintained remission for more than 3 years without any serious adverse event. Our case suggests that enteritis and arthritis in inflammatory bowel disease may be different in pathophysiology and raises the possible usefulness of simultaneous inhibition of two inflammatory cytokines in such cases.

A Narrative Review of Cytokine Networks: Pathophysiological and Therapeutic Implications for Inflammatory Bowel Disease Pathogenesis

Inflammatory bowel disease (IBD) is a lifelong inflammatory immune mediated disorder, encompassing Crohn's disease (CD) and ulcerative colitis (UC); however, the cause and specific pathogenesis of IBD is yet incompletely understood. Multiple cytokines produced by different immune cell types results in complex functional networks that constitute a highly regulated messaging network of signaling pathways. Applying biological mechanisms underlying IBD at the single omic level, technologies and genetic engineering enable the quantification of the pattern of released cytokines and new insights into the cytokine landscape of IBD. We focus on the existing literature dealing with the biology of pro- or anti-inflammatory cytokines and interactions that facilitate cell-based modulation of the immune system for IBD inflammation. We summarize the main roles of substantial cytokines in IBD related to homeostatic tissue functions and the remodeling of cytokine networks in IBD, which may be specifically valuable for successful cytokine-targeted therapies via marketed products. Cytokines and their receptors are validated targets for multiple therapeutic areas, we review the current strategies for therapeutic intervention and developing cytokine-targeted therapies. New biologics have shown efficacy in the last few decades for the management of IBD; unfortunately, many patients are nonresponsive or develop therapy resistance over time, creating a need for novel therapeutics. Thus, the treatment options for IBD beyond the immune-modifying anti-TNF agents or combination therapies are expanding rapidly. Further studies are needed to fully understand the immune response, networks of cytokines, and the direct pathogenetic relevance regarding individually tailored, safe and efficient targeted-biotherapeutics.

RORγt inhibition ameliorates IL-23 driven experimental psoriatic arthritis by predominantly modulating γδ-T cells

OBJECTIVE

Divergent therapeutic outcomes on different disease domains have been noted with IL-23 and IL-17A-blockade in PsA. Therefore, elucidating the role of RORγt, the master regulator of type 17 immune responses, is of potential therapeutic interest. To this end, RORγt inhibition was assessed in combined skin, joint and gut inflammation in vivo, using a PsA model.

METHODS

We tested the efficacy of a RORγt antagonist in B10.RIII mice challenged with systemic overexpression of IL-23 by hydrodynamic injection of IL-23 enhanced episomal vector (IL-23 EEV). Clinical outcomes were evaluated by histopathology. Bone density and surface erosions were examined using micro-computed tomography. Cytokine production was measured in serum and by intracellular flow cytometry. Gene expression in PsA-related tissues was analysed by qPCR.

RESULTS

RORγt-blockade significantly ameliorated psoriasis, peripheral arthritis and colitis development in IL-23 EEV mice (improvement of clinical scores and weight loss respectively by 91.8%, 58.2% and 7.0%, P < 0.001), in line with profound suppression of an enhanced type IL-17 immune signature in PsA-affected tissues. Moreover, inflammation-induced bone loss and bone erosions were reduced (P < 0.05 in calcaneus, P < 0.01 in tibia). Sustained IL-23 overexpression resulted in only mild signs of sacroiliitis. Gamma-delta (γδ)-T cells, the dominant source of T cell-derived IL-17A and IL-22, were expanded during IL-23 overexpression, and together with Th17 cells, clearly countered by RORγt inhibition (P < 0.001).

CONCLUSION

RORγt-blockade shows therapeutic efficacy in a preclinical PsA model with protection towards extra-musculoskeletal manifestations, reflected by a clear attenuation of type 17 cytokine responses by γδ-T cells and Th17 cells.

Inflammatory Cytokines in Psoriatic Arthritis: Understanding Pathogenesis and Implications for Treatment

Psoriatic arthritis (PsA) is a persistent, inflammatory disease that affects individuals with psoriasis, arthritis, and enthesitis. Research has demonstrated that inflammatory cytokines such as tumor necrosis factor-alpha (TNF-α), interleukin-23 (IL-23), and interleukin-17 (IL-17) play a pivotal role in both the onset and progression of PsA. These cytokines are generated by activated immune cells and stimulate the attraction of inflammatory cells to the synovium and joint tissues, resulting in the deterioration of cartilage and bone. The blocking of these cytokines has become a successful treatment strategy for PsA, as biological drugs that inhibit TNF-α, IL-23, and IL-17 have demonstrated notable clinical benefits. The association between PsA and other types of inflammatory cytokines or chemokines, excluding TNF-α, IL-23, and IL-17, has been extensively investigated in numerous studies. These findings may provide a chance for the discovery of novel therapeutic agents targeting other molecules, distinct from the currently approved biologics and targeted synthetic disease-modifying anti-rheumatic drugs. In this review, we discuss the current understanding of the role of inflammatory cytokines in PsA pathogenesis and clinical implications of targeting these cytokines for PsA treatment.

Phenotypic heterogeneity in psoriatic arthritis: towards tissue pathology-based therapy

Psoriatic arthritis (PsA) is a heterogeneous disease involving multiple potential tissue domains. Most outcome measures used so far in randomized clinical trials do not sufficiently reflect this domain heterogeneity. The concept that pathogenetic mechanisms might vary across tissues within a single disease, underpinning such phenotype diversity, could explain tissue-distinct levels of response to different therapies. In this Review, we discuss the tissue, cellular and molecular mechanisms that drive clinical heterogeneity in PsA phenotypes, and detail existing tissue-based research, including data generated using sophisticated interrogative technologies with single-cell precision. Finally, we discuss how these elements support the need for tissue-based therapy in PsA in the context of existing and new therapeutic modes of action, and the implications for future PsA trial outcomes and design.

Emerging story of gut dysbiosis in spondyloarthropathy: From gastrointestinal inflammation to spondyloarthritis

As a set of inflammatory disorders, spondyloarthritis (SpA) exhibits distinct pathophysiological, clinical, radiological, and genetic characteristics. Due to the extra-articular features of this disorder, early recognition is crucial to limiting disability and improving outcomes. Gut dysbiosis has been linked to SpA development as evidence grows. A pathogenic SpA process is likely to occur when a mucosal immune system interacts with abnormal local microbiota, with subsequent joint involvement. It is largely unknown, however, how microbiota alterations predate the onset of SpA within the “gut-joint axis”. New microbiome therapies, such as probiotics, are used as an adjuvant therapy in the treatment of SpA, suggesting that the modulation of intestinal microbiota and/or intestinal barrier function may contribute to the prevention of SpA. In this review, we highlight the mechanisms of SpA by which the gut microbiota impacts gut inflammation and triggers the activation of immune responses. Additionally, we analyze the regulatory role of therapeutic SpA medication in the gut microbiota and the potential application of probiotics as adjunctive therapy for SpA.

Signaling Pathways Associated with Chronic Wound Progression: A Systems Biology Approach

Previously we have shown that several oxidative stress-driven pathways in cutaneous chronic wounds are dysregulated in the first 48 h post-wounding. Here, we performed an RNASeq analysis of tissues collected up to day 20 after wounding, when we have determined full chronicity is established. Weighted Gene Correlation Network Analysis was performed in R segregating the genes into 14 modules. Genes in the modules significantly correlated (p < 0.05) to early and full chronicity were used for pathway analysis using pathfindR. In early chronicity, we observed enrichment of several pathways. Dysregulation of Ephrin/Eph signaling leads to growth cone collapse and impairs neuronal regeneration. Adra2b and Adra2a overexpression in early and full chronicity, respectively, decreased cAMP production and impaired re-epithelialization and granulation tissue formation. Several pathways involving a Smooth-muscle-actin (Acta1) were also enriched with Acta1 overexpression contributing to impaired angiogenesis. During full chronicity, the ‘JAK-STAT’ pathway was suppressed undermining host defenses against infection. Wnt signaling was also suppressed, impairing re-epithelialization and granulation tissue formation. Biomarkers of cancer such as overexpression of SDC1 and constitutive activation of ErbB2/HER2 were also identified. In conclusion, we show that during progression to full chronicity, numerous signaling pathways are dysregulated, including some related to carcinogenesis, suggesting that chronic wounds behave much like cancer. Experimental verification in vivo could identify candidates for treatment of chronic wounds.

Exploring the Diverse Immune and Genetic Landscape of Psoriatic Arthritis

Psoriatic arthritis (PsA) is characterized by delays in diagnosis and modest effect of treatment in terms of joint response. An understanding of molecular pathomechanisms may aid in developing diagnostic and prognostic models. Genetic susceptibility (e.g., HLA class I genes, IL-23-related genes) can be responsible for the pattern of psoriatic manifestations and affinity for tissue involvement. Gene expression analysis indicates an inflammatory profile that is distinct for PsA, but disparate across tissues. This has clinical implications, as for example, dual blockade of IL-17A and IL-17F can lead to superior clinical effects if there is differential expression of IL-17 receptors in tissues. Structural and functional impairment of barrier tissue, including host-microbiome interactions, may be the source of immune activation. Interplay between different cell populations of innate and adaptive immunity is emerging, potentially providing a link between the transition of skin-to-joint disease. Th17 subsets, IL-17A, IL-17F and IL-23 are crucial in PsA pathogenesis, with both clinical and experimental evidence suggesting a differential molecular landscape in cutaneous and articular compartments.