The psoriasis-associated D10N variant of the adaptor Act1 with impaired regulation by the molecular chaperone hsp90

Act1 drives chemoresistance via regulation of antioxidant RNA metabolism and redox homeostasis

The IL-17 receptor adaptor molecule Act1, an RNA-binding protein, plays a critical role in IL-17-mediated cancer progression. Here, we report a novel mechanism of how IL-17/Act1 induces chemoresistance by modulating redox homeostasis through epitranscriptomic regulation of antioxidant RNA metabolism. Transcriptome-wide mapping of direct Act1-RNA interactions revealed that Act1 binds to the 5'UTR of antioxidant mRNAs and Wilms' tumor 1-associating protein (WTAP), a key regulator in m6A methyltransferase complex. Strikingly, Act1's binding sites are located in proximity to m6A modification sites, which allows Act1 to promote the recruitment of elF3G for cap-independent translation. Loss of Act1's RNA binding activity or Wtap knockdown abolished IL-17-induced m6A modification and translation of Wtap and antioxidant mRNAs, indicating a feedforward mechanism of the Act1-WTAP loop. We then developed antisense oligonucleotides (Wtap ASO) that specifically disrupt Act1's binding to Wtap mRNA, abolishing IL-17/Act1-WTAP-mediated antioxidant protein production during chemotherapy. Wtap ASO substantially increased the antitumor efficacy of cisplatin, demonstrating a potential therapeutic strategy for chemoresistance.

Unveiling the role of IL-17: Therapeutic insights and cardiovascular implications

Interleukin-17 (IL-17), a pivotal cytokine in immune regulation, has attracted significant attention in recent years due to its roles in various physiological and pathological processes. This review explores IL-17 in immunological context, emphasizing its structure, production, and signaling pathways. Specifically, we explore its involvement in inflammatory diseases and autoimmune diseases, with a notable focus on its emerging implications in cardiovascular system. Through an array of research insights, IL-17 displays multifaceted functions yet awaiting comprehensive discovery. Highlighting therapeutic avenues, we scrutinize the efficacy and clinical application of four marketed IL-17 mAbs along other targeted therapies, emphasizing their potential in immune-mediated disease management. Additionally, we discussed the novel IL-17D-CD93 axis, elucidating recent breakthroughs in their biological function and clinical implications, inviting prospects for transformative advancements in immunology and beyond.

The Role of Alarmins in the Pathogenesis of Rheumatoid Arthritis, Osteoarthritis, and Psoriasis

Alarmins are immune-activating factors released after cellular injury or death. By secreting alarmins, cells can interact with immune cells and induce a variety of inflammatory responses. The broad family of alarmins involves several members, such as high-mobility group box 1, S100 proteins, interleukin-33, and heat shock proteins, among others. Studies have found that the concentrations and expression profiles of alarmins are altered in immune-mediated diseases. Furthermore, they are involved in the pathogenesis of inflammatory conditions. The aim of this narrative review is to present the current evidence on the role of alarmins in rheumatoid arthritis, osteoarthritis, and psoriasis. We discuss their potential involvement in mechanisms underlying the progression of these diseases and whether they could become therapeutic targets. Moreover, we summarize the impact of pharmacological agents used in the treatment of these diseases on the expression of alarmins.

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.

Damage-Associated Molecular Patterns, a Class of Potential Psoriasis Drug Targets

Psoriasis is a chronic skin disorder that involves both innate and adaptive immune responses in its pathogenesis. Local tissue damage is a hallmark feature of psoriasis and other autoimmune diseases. In psoriasis, damage-associated molecular patterns (DAMPs) released by damaged local tissue act as danger signals and trigger inflammatory responses by recruiting and activating immune cells. They also stimulate the release of pro-inflammatory cytokines and chemokines, which exacerbate the inflammatory response and contribute to disease progression. Recent studies have highlighted the role of DAMPs as key regulators of immune responses involved in the initiation and maintenance of psoriatic inflammation. This review summarizes the current understanding of the immune mechanism of psoriasis, focusing on several important DAMPs and their mechanisms of action. We also discussed the potential of DAMPs as diagnostic and therapeutic targets for psoriasis, offering new insights into the development of more effective treatments for this challenging skin disease.

The IL-17 family in diseases: from bench to bedside

The interleukin-17 (IL-17) family comprises six members (IL-17A-17F), and recently, all of its related receptors have been discovered. IL-17 was first discovered approximately 30 years ago. Members of this family have various biological functions, including driving an inflammatory cascade during infections and autoimmune diseases, as well as boosting protective immunity against various pathogens. IL-17 is a highly versatile proinflammatory cytokine necessary for vital processes including host immune defenses, tissue repair, inflammatory disease pathogenesis, and cancer progression. However, how IL-17 performs these functions remains controversial. The multifunctional properties of IL-17 have attracted research interest, and emerging data have gradually improved our understanding of the IL-17 signaling pathway. However, a comprehensive review is required to understand its role in both host defense functions and pathogenesis in the body. This review can aid researchers in better understanding the mechanisms underlying IL-17's roles in vivo and provide a theoretical basis for future studies aiming to regulate IL-17 expression and function. This review discusses recent progress in understanding the IL-17 signaling pathway and its physiological roles. In addition, we present the mechanism underlying IL-17's role in various pathologies, particularly, in IL-17-induced systemic lupus erythematosus and IL-17-related tumor cell transformation and metastasis. In addition, we have briefly discussed promising developments in the diagnosis and treatment of autoimmune diseases and tumors.

Genome-wide DNA methylation and transcription analysis in psoriatic epidermis

Aim: To identify DNA methylation and transcription biomarkers in the psoriatic epidermis. Materials & methods: Gene transcription and DNA methylation datasets of psoriatic epidermal tissue were obtained from the Gene Expression Omnibus. Machine learning algorithm analysis and weighted gene coexpression network analysis were carried out to screen hub genes. Results: Differentially methylated and expressed genes were identified in the psoriatic epidermis. Six hub genes were selected - GZMB, CRIP1, S100A12, ISG15, CRABP2 and VNN1 - whose transcript levels showed a significant correlation with Psoriasis Area and Severity Index scores and immune infiltration. Conclusion: Psoriatic epidermis is primarily in a hypermethylated status. Epidermis-specific hub differentially methylated and expressed genes are potential biomarkers to help judge the condition of psoriasis.

TRAF3IP2-IL-17 Axis Strengthens the Gingival Defense against Pathogens

Recent genome-wide association studies have suggested novel risk loci associated with periodontitis, which is initiated by dysbiosis in subgingival plaque and leads to destruction of teeth-supporting structures. One such genetic locus was the tumor necrosis factor receptor-associated factor 3 interacting protein 2 (TRAF3IP2), a gene encoding the gate-keeping interleukin (IL)-17 receptor adaptor. In this study, we first determined that carriers of the lead exonic variant rs13190932 within the TRAF3IP2 locus combined with a high plaque microbial burden was associated with more severe periodontitis than noncarriers. We then demonstrated that TRAF3IP2 is essential in the IL-17-mediated CCL2 and IL-8 chemokine production in primary gingival epithelial cells. Further analysis suggested that rs13190932 may serve a surrogate variant for a genuine loss-of-function variant rs33980500 within the same gene. Traf3ip2 null mice (Traf3ip2^-/-) were more susceptible than wild-type (WT) mice to the Porphyromonas gingivalis-induced periodontal alveolar bone loss. Such bone loss was associated with a delayed P. gingivalis clearance and an attenuated neutrophil recruitment in the gingiva of Traf3ip2^-/- mice. Transcriptomic data showed decreased expression of antimicrobial genes, including Lcn2, S100a8, and Defb1, in the Traf3ip2^-/- mouse gingiva in comparison to WT mice prior to or upon P. gingivalis oral challenge. Further 16S ribosomal RNA sequencing analysis identified a distinct microbial community in the Traf3ip2^-/- mouse oral plaque, which was featured by a reduced microbial diversity and an overabundance of Streptococcus genus bacteria. More P. gingivalis was observed in the Traf3ip2^-/- mouse gingiva than WT control animals in a ligature-promoted P. gingivalis invasion model. In agreement, neutrophil depletion resulted in more local gingival tissue invasion by P. gingivalis. Thus, we identified a homeostatic IL-17-TRAF3IP2-neutrophil axis underpinning host defense against a keystone periodontal pathogen.

Lipidomic profiling reveals metabolic signatures in psoriatic skin lesions

Psoriasis is a chronic immune-mediated inflammatory disease. Lipids play an important role in regulating the inflammatory response. However, the alteration of lipids involved in psoriasis particular in skin lesions remain unclear. Here, we performed the lipidomics to investigate lipid profiling in the skin lesions of the imiquimod-induced psoriasis-like dermatitis and psoriasis patients. The findings showed that ceramides phosphate (CerP) and ceramides were enriched in psoriatic lesions compared with controls from both psoriasis patients and psoriasis-like mouse model. Psoriasis patients were classified into two subtypes, the CC1 and CC2, by consensus clustering of these lipid signatures. The CC1 was characterized by the higher levels of CerP, uric acid, and more severe psoriasis, compared with CC2 subtype. Interestingly, ceramide-1-phosphate (C1P), dramatically enriched in CC1 subtype, facilitated imiquimod-induced psoriasis-like inflammatory responses. Mechanistically, C1P induced the expression of inflammatory factors and activated DNA replication and cell cycle signaling pathways in the primary keratinocytes. Inhibiting the production of C1P with ceramide kinase inhibitor effectively alleviated the imiquimod-induced psoriasis-like inflammation. Taken together, we described the landscape of lipids alteration and established lipids classification based on pattern of abundance of lipids in psoriatic skin lesions. Suppression of C1P pathway is a novel potential strategy for psoriasis treatment.

Impact of TRAF3IP2, IL10 and HCP5 Genetic Polymorphisms in the Response to TNF-i Treatment in Patients with Psoriatic Arthritis

Psoriatic arthritis (PsA) is a chronic inflammatory rheumatic disease. The introduction of therapy with biological drugs is promising, even if the efficacy is very variable. Since the response to drugs is a complex trait, identifying genetic factors associated to treatment response could help define new biomarkers for a more effective and personalized therapy. This study aimed to evaluate the potential role of polymorphisms in genes involved in PsA susceptibility as predictors of therapy efficacy. Nine polymorphisms were analyzed in a cohort of 163 PsA patients treated with TNF-i. To evaluate the treatment response, the DAPsA score was estimated for each patient. The possible association between the selected SNPs and mean values of DAPsA differences, at 22 and 54 weeks from the beginning of the treatment, were evaluated by t-test. Patients carrying the variant allele of TRAF3IP2 seemed to respond better to treatment, both at 22 and 54 weeks. This variant allele was also associated with an improvement in joint involvement. In contrast, patients carrying the IL10 variant allele showed an improvement lower than patients with the wild-type genotype at 54 weeks. Our results suggest that polymorphisms in genes associated with PsA susceptibility could also play a role in TNF-i treatment response.

The Expanding Role of Extracellular Traps in Inflammation and Autoimmunity: The New Players in Casting Dark Webs

The first description of a new form of neutrophil cell death distinct from that of apoptosis or necrosis was discovered in 2004 and coined neutrophil extracellular traps "(NETs)" or "NETosis". Different stimuli for NET formation, and pathways that drive neutrophils to commit to NETosis have been elucidated in the years that followed. Critical enzymes required for NET formation have been discovered and targeted therapeutically. NET formation is no longer restricted to neutrophils but has been discovered in other innate cells: macrophages/monocytes, mast Cells, basophils, dendritic cells, and eosinophils. Furthermore, extracellular DNA can also be extruded from both B and T cells. It has become clear that although this mechanism is thought to enhance host defense by ensnaring bacteria within large webs of DNA to increase bactericidal killing capacity, it is also injurious to innocent bystander tissue. Proteases and enzymes released from extracellular traps (ETs), injure epithelial and endothelial cells perpetuating inflammation. In the context of autoimmunity, ETs release over 70 well-known autoantigens. ETs are associated with pathology in multiple diseases: lung diseases, vasculitis, autoimmune kidney diseases, atherosclerosis, rheumatoid arthritis, cancer, and psoriasis. Defining these pathways that drive ET release will provide insight into mechanisms of pathological insult and provide potential therapeutic targets.

The Molecular Mechanisms of Intestinal Inflammation and Fibrosis in Crohn’s Disease

Crohn’s disease (CD) is an inflammatory bowel disease (IBD) with repeated remissions and relapses. As the disease progresses, fibrosis and narrowing of the intestine occur, leading to severe complications such as intestinal obstruction. Endoscopic balloon dilatation, surgical stricture plasty, and bowel resection have been performed to treat intestinal stenosis. The clinical issue is that some patients with CD have a recurrence of intestinal stenosis even after the medical treatments. On the other hand, there exist no established medical therapies to prevent stenosis. With the progressive intestinal inflammation, cytokines and growth factors, including transforming growth factor (TGF-β), stimulate intestinal myofibroblasts, contributing to fibrosis of the intestine, smooth muscle hypertrophy, and mesenteric fat hypertrophy. Therefore, chronically sustained inflammation has long been considered a cause of intestinal fibrosis and stenosis. Still, even after the advent of biologics and tighter control of inflammation, intestinal fibrosis’s surgical rate has not necessarily decreased. It is essential to elucidate the mechanisms involved in intestinal fibrosis in CD from a molecular biological level to overcome clinical issues. Recently, much attention has been paid to several key molecules of intestinal fibrosis: peroxisome proliferator-activating receptor gamma (PPARγ), toll-like receptor 4 (TLR4), adherent-invasive Escherichia coli (AIEC), Th17 immune response, and plasminogen activator inhibitor 1 (PAI-1). As a major problem in the treatment of CD, the pathophysiology of patients with CD is not the same and varies depending on each patient. It is necessary to integrate these key molecules for a better understanding of the mechanism of intestinal inflammation and fibrosis.

Mouse Models of Psoriasis: A Comprehensive Review

The use of preclinical animal models of psoriasis has significantly increased over the last three decades, with each model having unique strengths and limitations. Some models translate better to human disease, and many have provided unique insight into psoriasis disease pathogenesis. In this comprehensive review, we present a comparative description and discussion of genetic mouse models, xenograft approaches, and elicited methods using cytokine injections into and topical imiquimod onto mice. We provide an inclusive list of genetically modified animals that have had imiquimod applied to or cytokines injected into their skin and describe the outcomes of these manipulations. This review will provide a valuable resource for those interested in working with psoriasis animal models.

HSP90 inhibitor RGRN-305 for oral treatment of plaque type psoriasis: efficacy, safety and biomarker results in an open-label proof-of-concept study

BACKGROUND

HSP90 is a downstream regulator of tumor necrosis factor α (TNFα) and interleukin (IL)-17A signaling and may therefore serve as a novel target in the treatment of psoriasis.

OBJECTIVE

This phase 1b proof-of-concept study was undertaken to evaluate the safety and efficacy of a novel HSP90 inhibitor (RGRN-305) in the treatment of plaque psoriasis.

METHODS

An open-label, single-arm, dose-selection, single-center proof-of-concept study. Patients with plaque psoriasis were treated with 250 mg or 500 mg RGRN-305 daily for 12 weeks. Efficacy was evaluated clinically using Psoriasis Area and Severity Index (PASI), body surface area (BSA), and Physician Global Assessment (PGA) scores and by Dermatology Life Quality Index (DLQI). Skin biopsies collected at baseline and at 4, 8, and 12 weeks after treatment start were used for immunohistochemical staining and for gene expression analysis. Safety was monitored via laboratory tests, vital signs, ECG, and physical examinations.

RESULTS

Six of the eleven patients completing the study responded to RGRN-305 with a PASI improvement between 71% and 94%, whereas five patients were considered nonresponders with a PASI response < 50%. No severe adverse events were reported. Four of seven patients treated with 500 mg RGRN-305 daily experienced a mild to moderate exanthematous drug induced eruption due to study treatment. Two patients chose to discontinue the study due to this exanthematous eruption. RGRN-305 treatment resulted in pronounced inhibition of the IL-23, TNFα, and IL-17A signaling pathways and normalization of both histological changes and psoriatic lesion gene expression profiles in patients responding to treatment.

CONCLUSION

Treatment with RGRN-305 showed an acceptable safety, especially in the low-dose group, and was associated with clinically meaningful improvement in a subset of patients with plaque psoriasis, indicating that HSP90 may serve as a novel future target in psoriasis treatment.

Key Signaling Pathways in Psoriasis: Recent Insights from Antipsoriatic Therapeutics

Psoriasis is a common chronic inflammatory skin disease associated with several comorbidities and reduced quality of life. In the past decades, highly effective targeted therapies have led to breakthroughs in the management of psoriasis, providing important insights into the pathogenesis. This article reviews the current concepts of the pathophysiological pathways and the recent progress in antipsoriatic therapeutics, highlighting key targets, signaling pathways and clinical effects in psoriasis.

Identification of a Long Noncoding RNA TRAF3IP2-AS1 as Key Regulator of IL-17 Signaling through the SRSF10-IRF1-Act1 Axis in Autoimmune Diseases

IL-17A plays an essential role in the pathogenesis of many autoimmune diseases, including psoriasis and multiple sclerosis. Act1 is a critical adaptor in the IL-17A signaling pathway. In this study, we report that an anti-sense long noncoding RNA, TRAF3IP2-AS1, regulates Act1 expression and IL-17A signaling by recruiting SRSF10, which downregulates the expression of IRF1, a transcriptional factor of Act1. Interestingly, we found that a psoriasis-susceptible variant of TRAF3IP2-AS1 A4165G (rs13210247) is a gain-of-function mutant. Furthermore, we identified a mouse gene E130307A14-Rik that is homologous to TRAF3IP2-AS1 and has a similar ability to regulate Act1 expression and IL-17A signaling. Importantly, treatment with lentiviruses expressing E130307A14-Rik or SRSF10 yielded therapeutic effects in mouse models of psoriasis and experimental autoimmune encephalomyelitis. These findings suggest that TRAF3IP2-AS1 and/or SRSF10 may represent attractive therapeutic targets in the treatment of IL-17-related autoimmune diseases, such as psoriasis and multiple sclerosis.

Downregulation of Macrophage-Specific Act-1 Intensifies Periodontitis and Alveolar Bone Loss Possibly via TNF/NF-κB Signaling

Periodontitis is a chronic inflammatory oral disease that affects almost half of the adult population. NF-κB activator 1 (Act1) is mainly expressed in immune cells, including macrophages, and modulates immune cells' function to regulate inflammation in inflammatory diseases. Macrophages play a vital role in the pathophysiology of periodontitis. However, the effect of macrophage-specific Act1 on periodontitis has not been investigated yet. This study aims to unravel the role of macrophage-specific Act1 on the pathophysiology of periodontitis. The expression of Act1 in healthy and periodontitis periodontal tissue was confirmed by immunohistochemistry. Macrophage-specific Act1 expression downregulated (anti-Act1) mice were developed by inserting anti-Act1 antisense oligonucleotides after the CD68 promoter of C57BL/6 mice. Ligature-induced periodontitis (LIP) was induced in anti-Act1 mice and wildtype mice. Micro-CT, histology, and TRAP staining analyzed the periodontal tissue status, alveolar bone loss, and osteoclast numbers. Immunohistochemistry, RT-qPCR, and ELISA analyzed the inflammatory cells infiltration, expression of inflammatory cytokines, and M1/M2 macrophage polarization. mRNA sequencing of in vitro bacterial lipopolysaccharide (LPS)-treated peritoneal macrophages analyzed the differentially expressed genes in anti-Act1 mice during inflammation. Anti-Act1 mice showed aggravated periodontitis and alveolar bone loss compared to wildtype. Periodontitis-affected periodontal tissue (PAPT) of anti-Act1 mice showed a higher degree of macrophage infiltration, and M1 macrophage polarization compared to wildtype. Levels of pro-inflammatory cytokines (IL-1β, IL-6, and TNFα), and macrophage activity-related factors (CCL2, CCL3, and CCL4) were robustly high in PAPT of anti-Act1 mice compared to wildtype. mRNA sequencing and KEGG analysis showed activated TNF/NF-κB signaling in LPS-treated macrophages from anti-Act1 mice. In vitro studies on LPS-treated peritoneal macrophages from anti-act1 mice showed a higher degree of cell migration and expression of inflammatory cytokines, macrophage activity-related factors, M1 macrophage-related factors, and TNF/NF-κB signaling related P-p65 protein. In conclusion, downregulation of macrophage-specific Act1 aggravated periodontitis, alveolar bone loss, macrophage infiltration, inflammation, and M1 macrophage polarization. Furthermore, LPS-treated macrophages from anti-Act1 mice activated TNF/NF-κB signaling. These results indicate the distinct role of macrophage-specific Act1 on the pathophysiology of periodontitis possibly via TNF/NF-κB signaling.

The HSP90 inhibitor RGRN-305 exhibits strong immunomodulatory effects in human keratinocytes

Keratinocytes are the key cellular target for IL-17A-mediated effects in psoriasis and HSP90 is important for IL-17A-mediated signalling. RGRN-305 is a novel HSP90 inhibitor reported to reduce psoriatic phenotypes in preclinical animal models. The aim of this study was to investigate the effect of RGRN-305 on a psoriasis-like inflammatory response in human keratinocytes in vitro. Using RT-qPCR, we demonstrated a significantly increased expression of the HSP90 isoforms HSP90AB1, HSP90B1 and TRAP1 in lesional compared with non-lesional psoriatic skin. In a psoriasis-like setting where keratinocytes were stimulated with TNFα and/or IL-17A, we analysed the mRNA expression using the NanoString nCounter technology and demonstrated that the HSP90 inhibitor RGRN-305 significantly reduced the IL-17A- and TNFα-induced gene expression of a number of proinflammatory genes, including the psoriasis-associated genes CCL20, NFKBIZ, IL36G and IL23A. In agreement with the mRNA data, the protein level of CCL20, IκBζ and IL-36γ were inhibited by RGRN-305 as demonstrated by western blotting and ELISA. Interestingly, when keratinocytes were stimulated with a TLR3 agonist, RGRN-305 also demonstrated potent immunomodulatory effects, significantly inhibiting poly(I:C)-induced expression of the proinflammatory genes TNFα, IL1B, IL6 and IL23A. Taken together, our data support a role for HSP90 not only in the pathogenesis of psoriasis, but also in broader immune responses. Therefore, HSP90 provides an attractive target for the treatment of psoriasis and other diseases where the innate immune system plays an important role.

ACT1 Is Required for Murine IL-23-Induced Psoriasiform Inflammation Potentially Independent of E3 Ligase Activity

Psoriasis is a debilitating skin disease characterized by epidermal thickening, abnormal keratinocyte differentiation, and proinflammatory immune cell infiltrate into the affected skin. IL-17A plays a critical role in the etiology of psoriasis. ACT1, an intracellular adaptor protein and a putative ubiquitin E3 ligase, is essential for signal transduction downstream of the IL-17A receptor. Thus, IL-17A signaling in general, and ACT1 specifically, represent attractive targets for the treatment of psoriasis. We generated Act1 knockout and Act1 L286G knockin (ligase domain) mice to investigate the potential therapeutic effects of targeting ACT1 and its U-box domain, respectively. Act1 knockout, but not Act1 L286G knockin, mice were resistant to increases in CXCL1 plasma levels induced by subcutaneous injection of recombinant IL-17A. Moreover, in a mouse model of psoriasiform dermatitis induced by intradermal IL-23 injection, Act1 knockout, but not Act1 L286G knockin, was protective against increases in ear thickness, keratinocyte hyperproliferation, expression of genes for antimicrobial peptides and chemokines, and infiltration of monocytes and macrophages. Our studies highlight the critical contribution of ACT1 to proinflammatory skin changes mediated by the IL-23/IL-17 signaling axis and illustrate the need for further insight into ACT1 E3 ligase activity.

A novel TRAF3IP2 variant causing familial scarring alopecia with mixed features of discoid lupus erythematosus and folliculitis decalvans

Discoid lupus erythematosus (DLE) is an autoimmune disorder with a poorly defined etiology. Despite epidemiologic gender and ethnic biases, a clear genetic basis for DLE remains elusive. In this study, we used exome and RNA sequencing technologies to characterize a consanguineous Lebanese family with four affected individuals who presented with classical scalp DLE and generalized folliculitis. Our results unraveled a novel biallelic variant c.1313C > A leading to a missense substitution p.(Thr438Asn) in TRAF3IP2(NM_147200.3). Expression studies in cultured cells revealed mis-localization of the mutated protein. Functional characterization of the mutated protein showed significant reduction in the physical interaction with the interleukin 17-A receptor (IL17RA), while interaction with TRAF6 was unaffected. By conducting a differential genome-wide transcriptomics analysis between affected and non-affected individuals, we showed that the hair follicle differentiation pathway is drastically suppressed, whereas cytokine and inflammation responses are significantly upregulated. Furthermore, our results were highly concordant with molecular signatures in patients with DLE from a public dataset. In conclusion, this is the first report on a new putative role for TRAF3IP2 in the etiology of DLE. The identified molecular features associated with this gene could pave the way for better DLE-targeted treatment.

Recent genetic advances in innate immunity of psoriatic arthritis

Psoriatic arthritis (PsA) is a heterogeneous disease that affects multiple organ systems including the peripheral and axial joints, entheses and nails. PsA is associated with significant comorbidities including cardiovascular, metabolic, and psychiatric diseases. The pathogenesis of PsA is complex and involves genetic, immunologic and environmental factors. Recent evidence suggests the heritability for PsA to be stronger and distinct from that of PsC. Prominent genes identified via GWAS for PsA include HLA-B/C, HLAB, IL12B, IL23R, TNP1, TRAF3IP3, and REL. We review the genetics of psoriatic arthritis and discuss the role of the innate immune system as important in the pathogenesis of PsA by focusing on key signaling pathways and cellular makeup. Understanding the candidate genes identified in PsA highlights pathways of critical importance to the pathogenesis of psoriatic disease including the key role of the innate immune response, mediated through IL-23/IL-17 axis, RANK and NFκB signaling pathways.

Neonatal-derived IL-17 producing dermal γδ T cells are required to prevent spontaneous atopic dermatitis

Atopic Dermatitis (AD) is a T cell-mediated chronic skin disease and is associated with altered skin barrier integrity. Infants with mutations in genes involved in tissue barrier fitness are predisposed towards inflammatory diseases, but most do not develop or sustain the diseases, suggesting that there exist regulatory immune mechanisms to prevent aberrant inflammation. The absence of one single murine dermal cell type, the innate neonatal-derived IL-17 producing γδ T (Tγδ17) cells, from birth resulted in spontaneous, highly penetrant AD with many of the major hallmarks of human AD. In Tγδ17 cell-deficient mice, basal keratinocyte transcriptome was altered months in advance of AD induction. Tγδ17 cells respond to skin commensal bacteria and the fulminant disease in their absence was driven by skin commensal bacteria dysbiosis. AD in this model was characterized by highly expanded dermal αβ T clonotypes that produce the type three cytokines, IL-17 and IL-22. These results demonstrate that neonatal Tγδ17 cells are innate skin regulatory T cells that are critical for skin homeostasis, and that IL-17 has dual homeostatic and inflammatory function in the skin.

Low Levels of Vitamin D Promote Memory B Cells in Lupus

Background: Vitamin D deficiency is a known risk factor for Systemic Lupus Erythematosus (SLE), yet clinical trials have not demonstrated efficacy and few studies have utilized lupus models to understand the mechanism underlying this relationship. The Act1-/- mouse is a spontaneous model of lupus and Sjögren's syndrome, characterized by increased Th17 cells and peripheral B cell expansion. Vitamin D3 has anti-inflammatory properties, reduces Th17 cells and impairs B cell differentiation/activation. Therefore, we assessed how varying amounts of vitamin D3 affected lupus-like disease in the Act1-/- mouse. Methods: Act1-/- mice were fed either low/restricted (0 IU/kg), normal (2 IU/kg), or high/supplemented (10 IU/kg) vitamin D3 chow for 9 weeks, after which lupus-like features were analyzed. Results: While we found no differences in Th17 cells between vitamin D3 groups, vitamin D3 restriction specifically promoted memory B cell development, accompanied by elevated levels of serum IgM, IgG1, IgG3, and anti-dsDNA IgG. A similar significant negative association between serum vitamin D and memory B cells was confirmed in a cohort of SLE patients. Conclusion: Low levels of vitamin D3 are associated with elevated levels of memory B cells in an animal model of lupus and well-controlled SLE patients.

IL-17 receptor-based signaling and implications for disease

IL-17 is a highly versatile pro-inflammatory cytokine crucial for a variety of processes, including host defense, tissue repair, the pathogenesis of inflammatory disease and the progression of cancer. In contrast to its profound impact in vivo, IL-17 exhibits surprisingly moderate activity in cell-culture models, which presents a major knowledge gap about the molecular mechanisms of IL-17 signaling. Emerging studies are revealing a new dimension of complexity in the IL-17 pathway that may help explain its potent and diverse in vivo functions. Discoveries of new mRNA stabilizers and receptor-directed mRNA metabolism have provided insights into the means by which IL-17 cooperates functionally with other stimuli in driving inflammation, whether beneficial or destructive. The integration of IL-17 with growth-receptor signaling in specific cell types offers new understanding of the mitogenic effect of IL-17 on tissue repair and cancer. This Review summarizes new developments in IL-17 signaling and their pathophysiological implications.

Pathogenic role of palatine tonsils in palmoplantar pustulosis: A review

Palmoplantar pustulosis (PPP) is characterized by symmetrical, erythematous, scaly plaques, with numerous, sterile, non-bacterial, pinpoint pustules, which are restricted to the palms and soles. Because several reports have described the efficacy of tonsillectomy for improvement in PPP skin lesions, we consider that PPP is tonsil-induced autoimmune/inflammatory syndrome (TIAS) while other factors are also involved in the pathogenesis of PPP. Here, the association between PPP pathogenesis and TIAS was examined, with a focus on results of previous studies. PPP patients show a hyperimmune response to indigenous bacteria such as α-streptococci, due to impaired immunological tolerance towards such organisms. Such a novel immune response leads to T-cell activation through the abnormal expression of secondary stimulation molecules, including cytotoxic T-lymphocyte-associated antigen 4, inducible T-cell co-stimulator and Smad7, in the tonsils of PPP patients. Activated tonsillar T cells express cutaneous lymphocyte antigen (CLA), CCR6 and β1-integrin, enter the blood circulation and are recruited to PPP skin lesions. Within lesions, T cells roll onto endothelial cells through the interaction between CLA and E-selectin, migrate into the extravascular area through β1-integrin-vascular cell adhesion molecule 1 binding, and assemble in the skin through CCL20-CCR6 binding. Hyperimmune responses to autoantigens such as keratin and heat shock proteins could also be involved in PPP pathogenesis, through the stimulation of the T-helper 17 reaction.

Interleukin-17: Functional and Structural Features, Application as a Therapeutic Target

Cytokines of the IL-17 family play a key role in the host organism defense against bacterial and fungal infections. At the same time, upregulated synthesis of IL-17 cytokines is associated with immunoinflammatory and autoimmune diseases such as psoriasis, rheumatoid arthritis, systemic lupus erythematosus, and others. The members of this family are important therapeutic targets in the treatment of various human chronic inflammatory disorders. Elucidation of signaling pathways involving IL-17 family proteins and analysis of the structure of cytokine complexes with specific antibodies, inhibitors, and receptors are essential for the development of new drugs for the therapy of immunoinflammatory rheumatic diseases.

Immune Control by TRAF6-Mediated Pathways of Epithelial Cells in the EIME (Epithelial Immune Microenvironment)

In the protective responses of epithelial tissues, not only immune cells but also non-immune cells directly respond to external agents. Epithelial cells can be involved in the organization of immune responses through two phases. First, the exogenous harmful agents trigger the primary responses of the epithelial cells leading to various types of immune cell activation. Second, cytokines produced by the immune cells that are activated directly by the external agents and indirectly by the epithelial cell products elicit the secondary responses giving rise to further propagation of immune responses. TRAF6 is a ubiquitin E3 ligase, which intermediates between various types of receptors for exogenous agents or endogenous mediators and activation of subsequent transcriptional responses via NF-kappaB and MAPK pathways. TRAF6 ubiquitously participates in many protective responses in immune and non-immune cells. Particularly, epithelial TRAF6 has an essential role in the primary and secondary responses via driving type 17 response in psoriatic inflammation of the skin. Consistently, many psoriasis susceptibility genes encode the TRAF6 signaling players, such as ACT1 (TRAF3IP2), A20 (TNFAIP3), ABIN1 (TNIP1), IL-36Ra (IL36RN), IkappaBzeta (NFKBIZ), and CARD14. Herein, we describe the principal functions of TRAF6, especially in terms of positive and regulatory immune controls by interaction between immune cells and epithelial cells. In addition, we discuss how TRAF6 in the epithelial cells can organize the differentiation of immune responses and drive inflammatory loops in the epithelial immune microenvironment, which is termed EIME.

Knockdown of TRAF3IP2 suppresses the expression of VEGFA and the proliferation of keratinocytes and vascular endothelial cells

OBJECTIVE

To investigate the expression level of TRAF3IP2 in psoriasis lesion, and to explore the functional roles of TRAF3IP2 on proliferation, apoptosis, cytokine expression and secretion of both keratinocytes and vascular endothelial cells in vitro.

METHODS

The expression of TRAF3IP2 in skin samples of patients with psoriasis was analyzed by immunohistochemistry and qRT-PCR. To identify the effect of TRAF3IP2 knockdown on HaCaT and HUVEC cells, a plasmid vector expressing siRNA targeting TRAF3IP2 mRNA was designed and transfected into cells with Lipofectamine 2000. The levels of cytokines were identified using the ELISA Kits and qRT-PCR. Furthermore, cell proliferation, cell cycle and apoptosis were examined by using MTT, PI and Annexin V-FITC/7AAD assays, respectively. Furthermore, the expression of apoptosis-related proteins (Cleaved-Caspase 3, Caspase 3 and Bax) were detected by western blotting.

RESULTS

TRAF3IP2 was significantly upregulated in psoriasis lesion. TRAF3IP2 knockdown reduced the expression of vascular endothelial growth factor A (VEGFA) and the release of IL-6, and IL-8, but had no effect on IL-23 in both HaCaT and HUVEC cells. In addition, knockdown of TRAF3IP2 significantly inhibited cell proliferation through blocking the cell cycle in the G2/M phase. Moreover, knockdown of TRAF3IP2 increased the expression of Caspase 3, Cleaved-Caspase 3 and Bax, which was supported by the increased apoptosis of both HaCaT and HUVEC cells.

CONCLUSION

Taken together, these results indicated that TRAF3IP2 might play a contributive role in the pathogenesis of psoriasis and may serve as a new target for the treatment of psoriasis. VEGF related pathways may be involved in the mechanism beneath.

Neutrophil Extracellular Traps Induce Human Th17 Cells: Effect of Psoriasis-Associated TRAF3IP2 Genotype

Psoriasis lesions are rich in IL-17-producing T cells as well as neutrophils, which release webs of DNA-protein complexes known as neutrophil extracellular traps (NETs). Because we and others have observed increased NETosis in psoriatic lesions, we hypothesized that NETs contribute to increased T helper type 17 (Th17) cells in psoriasis. After stimulating peripheral blood mononuclear cells with anti-CD3/CD28 beads for 7 days, we found significantly higher percentages of CD3⁺CD4⁺IL-17⁺ (Th17) cells in the presence versus absence of NETs, as assessed by flow cytometry, IL-17 ELISA, and IL17A/F and RORC mRNAs. Memory, but not naïve, T cells were competent and monocytes were required for CD3/CD28-mediated Th17 induction, with or without NETs. Th17 induction was enhanced by the T allele of rs33980500 (T/C), a psoriasis risk-associated variant in the TRAF3IP2 gene encoding the D10N variant of Act1, a key mediator of IL-17 signal transduction. Global transcriptome analysis of CD3/CD28-stimulated peripheral blood mononuclear cells by RNA sequencing confirmed the stimulatory effects of NETs, demonstrated NET-induced enhancement of cytokine gene expression, and verified that the effect of Act1 D10N was greater in the presence of NETs. Collectively, these results implicate NETs and the Act1 D10N variant in human Th17 induction from peripheral blood mononuclear cells, with ramifications for immunogenetic studies of psoriasis and other autoimmune diseases.

TLR-stimulated IRAKM activates caspase-8 inflammasome in microglia and promotes neuroinflammation

NLRP3 inflammasome plays a critical spatiotemporal role in the pathogenesis of experimental autoimmune encephalomyelitis (EAE). This study reports a mechanistic insight into noncanonical NLRP3 inflammasome activation in microglia for the effector stage of EAE. Microglia-specific deficiency of ASC (apoptosis-associated speck-like protein containing a C-terminal caspase-activation and recruitment [CARD] domain) attenuated T cell expansion and neutrophil recruitment during EAE pathogenesis. Mechanistically, TLR stimulation led to IRAKM-caspase-8-ASC complex formation, resulting in the activation of caspase-8 and IL-1β release in microglia. Noncanonical inflammasome-derived IL-1β produced by microglia in the CNS helped to expand the microglia population in an autocrine manner and amplified the production of inflammatory cytokines/chemokines. Furthermore, active caspase-8 was markedly increased in the microglia in the brain tissue from patients with multiple sclerosis. Taken together, our study suggests that microglia-derived IL-1β via noncanonical caspase-8-dependent inflammasome is necessary for microglia to exert their pathogenic role during CNS inflammation.

Alpinumisoflavone attenuates lipopolysaccharide-induced acute lung injury by regulating the effects of anti-oxidation and anti-inflammation both in vitro and in vivo

Alpinumisoflavone (AIF) is a plant-derived pyranoisoflavone that exhibits a number of pharmacological activities, but the protective effects of AIF against pulmonary inflammation are still unknown. This study aimed to investigate the anti-inflammatory effects and possible molecular mechanisms of AIF in both lipopolysaccharide (LPS)-stimulated macrophages and mice. The results revealed that AIF dramatically suppressed the production of pro-inflammatory mediators [including tumor necrosis factor (TNF)-α, interleukin (IL)-6, IL-1β, IL-17, intercellular adhesion molecule-1 (ICAM-1), and nitric oxide (NO)] and increased the levels of anti-oxidative enzymes [including catalase (CAT), heme oxygenase-1 (HO-1), glutathione peroxidase (GPx), and superoxide dismutase (SOD)] both in vitro and in vivo. Additionally, pre-treatment with AIF could not only significantly prevent histopathological changes and neutrophil infiltration but also decreased the expression levels of nuclear factor-kappa B (NF-κB), mitogen-activated protein kinases (MAPKs), and the nucleotide-binding domain-like receptor protein 3 (NLRP3) inflammasome, as well as IL-17 production in LPS-induced lung tissues. The anti-inflammatory effects of AIF were mediated by up-regulating anti-oxidative enzymes and suppressing the NF-κB, MAPK, NLRP3 inflammasome and IL-17 signaling pathways. This is the first study to reveal that AIF has a protective effect against LPS-induced lung injury in mice.

Act1 is a negative regulator in T and B cells via direct inhibition of STAT3

Although Act1 (adaptor for IL-17 receptors) is necessary for IL-17-mediated inflammatory responses, Act1- (but not Il17ra-, Il17rc-, or Il17rb-) deficient mice develop spontaneous SLE- and Sjögren's-like diseases. Here, we show that Act1 functions as a negative regulator in T and B cells via direct inhibition of STAT3. Mass spectrometry analysis detected an Act1-STAT3 complex, deficiency of Act1 (but not Il17ra-, Il17rc-, or Il17rb) results in hyper IL-23- and IL-21-induced STAT3 activation in T and B cells, respectively. IL-23R deletion or blockade of IL-21 ameliorates SLE- and Sjögren's-like diseases in Act1-/- mice. Act1 deficiency results in hyperactivated follicular Th17 cells with elevated IL-21 expression, which promotes T-B cell interaction for B cell expansion and antibody production. Moreover, anti-IL-21 ameliorates the SLE- and Sjögren's-like diseases in Act1-deficient mice. Thus, IL-21 blocking antibody might be an effective therapy for treating SLE- and Sjögren's-like syndrome in patients containing Act1 mutation.

Interleukin 17 Family Cytokines: Signaling Mechanisms, Biological Activities, and Therapeutic Implications

The cytokines of the interleukin 17 (IL-17) family play a central role in the control of infections, especially extracellular fungi. Conversely, if unrestrained, these inflammatory cytokines contribute to the pathology of numerous autoimmune and chronic inflammatory conditions. Recent advances have led to the approval of IL-17A-blocking biologics for the treatment of moderate to severe plaque psoriasis, but much remains to be understood about the biological functions, regulation, and signaling pathways downstream of these factors. In this review, we outline the current knowledge of signal transduction and known physiological activities of IL-17 family cytokines. We will highlight in particular the current understanding of these cytokines in the context of skin manifestations of disease.

The Act1 D10N missense variant impairs CD40 signaling in human B-cells

The TRAF3IP2 gene resides within one of at least 63 psoriasis susceptibility loci and encodes Act1, an adapter protein involved in IL-17 receptor and CD40 signaling pathways. TRAF3IP2 is distinctive (among <10% of candidate susceptibility genes) in that a strongly disease-associated variant encodes a missense SNP predicted to be functionally relevant (SNP rs33980500 C/T encoding Act1 pD10N). As assessed by flow cytometry, Act1 protein was expressed at the highest levels in monocytes, with lower levels in T-cells and B-cells. However, monocytes, T-cells and B-cells failed to respond to IL-17A stimulation of PBMC, as measured by flow cytometric determination of NF-κB phospho-p65. As an alternative stimulus, we treated PBMCs with trimerized recombinant human CD40L and assessed p65, p38 and Erk phosphorylation in CD19⁺ B-cells as a function of D10N genotype. The increase of phosphorylated p65, p38 and Erk was well-correlated across individuals, and CD40L-induced phosphorylation of p65, p38, and Erk was significantly attenuated in B-cells from Act1 D10N homozygotes, compared to heterozygotes and nullizygotes. Our results indicate that the Act1 D10N variant is a relevant genetic determinant of CD40L responsiveness in human B-cells, with the risk allele being associated with lower B-cell responses in an acute signaling context.

Targeting IL-17 in psoriatic arthritis

Psoriatic arthritis (PsA) is a chronic and progressive inflammatory arthritis intimately associated with psoriasis, and can be an impairing disease that leads to reduced quality of life and significant morbidity. Treatment often requires TNF antagonists, yet many patients with PsA are not responsive to the standard anti-TNF therapies. The interleukin-17 (IL-17)/IL-17 receptor (IL-17R) family has recently been implicated in the pathogenesis of PsA and psoriasis. Much enthusiasm has been generated for the development of biologics that target the IL-17 signaling pathway directly or indirectly, many of which have produced striking results in the setting of psoriasis and PsA. Herein, we review the role of IL-17 and the IL-17 receptor (IL-17R) in the pathogenesis of PsA, as well as the clinical evidence for IL-17 and IL-17R targeted therapeutics.

IL-17 Receptor A Maintains and Protects the Skin Barrier To Prevent Allergic Skin Inflammation

Atopic dermatitis (AD) is a common inflammatory skin disease affecting up to 20% of children and 3% of adults worldwide and is associated with dysregulation of the skin barrier. Although type 2 responses are implicated in AD, emerging evidence indicates a potential role for the IL-17A signaling axis in AD pathogenesis. In this study we show that in the filaggrin mutant mouse model of spontaneous AD, IL-17RA deficiency (Il17ra-/- ) resulted in severe exacerbation of skin inflammation. Interestingly, Il17ra-/- mice without the filaggrin mutation also developed spontaneous progressive skin inflammation with eosinophilia, as well as increased levels of thymic stromal lymphopoietin (TSLP) and IL-5 in the skin. Il17ra-/- mice have a defective skin barrier with altered filaggrin expression. The barrier dysregulation and spontaneous skin inflammation in Il17ra-/- mice was dependent on TSLP, but not the other alarmins IL-25 and IL-33. The associated skin inflammation was mediated by IL-5-expressing pathogenic effector Th2 cells and was independent of TCRγδ T cells and IL-22. An absence of IL-17RA in nonhematopoietic cells, but not in the hematopoietic cells, was required for the development of spontaneous skin inflammation. Skin microbiome dysbiosis developed in the absence of IL-17RA, with antibiotic intervention resulting in significant amelioration of skin inflammation and reductions in skin-infiltrating pathogenic effector Th2 cells and TSLP. This study describes a previously unappreciated protective role for IL-17RA signaling in regulation of the skin barrier and maintenance of skin immune homeostasis.

Dual Role of Act1 in Keratinocyte Differentiation and Host Defense: TRAF3IP2 Silencing Alters Keratinocyte Differentiation and Inhibits IL-17 Responses

TRAF3IP2 is a candidate psoriasis susceptibility gene encoding Act1, an adaptor protein with ubiquitin ligase activity that couples the IL-17 receptor to downstream signaling pathways. We investigated the role of Act1 in keratinocyte responses to IL-17 using a tetracycline inducible short hairpin RNA targeting TRAF3IP2. Tetracycline exposure for 7 days effectively silenced TRAF3IP2 mRNA and Act1 protein, resulting in 761 genes with significant changes in expression (495 down, 266 up; >1.5-fold, P < 0.05). Gene ontology analysis showed that genes affected by TRAF3IP2 silencing are involved in epidermal differentiation, with early differentiation genes (KRT1, KRT10, DSC1, DSG1) being down-regulated and late differentiation genes (SPRR2, SPRR3, LCE3) being up-regulated. AP1 binding sites were enriched upstream of genes up-regulated by TRAF3IP2 silencing. Correspondingly, nuclear expression of FosB and Fra1 was increased in TRAF3IP2-silenced cells. Many genes involved in host defense were induced by IL-17 in a TRAF3IP2-dependent fashion. Inflammatory differentiation conditions (serum addition for 4 days postconfluence) markedly amplified these IL-17 responses and increased basal levels and TRAF3IP2 silencing-dependent up-regulation of multiple late differentiation genes. These findings suggest that TRAF3IP2 may alter both epidermal homeostasis and keratinocyte defense responses to influence psoriasis risk.

IL-17 Signaling: The Yin and the Yang

Interleukin (IL)-17 is the founding member of a novel family of inflammatory cytokines. While the proinflammatory properties of IL-17 are key to its host-protective capacity, unrestrained IL-17 signaling is associated with immunopathology, autoimmune disease, and cancer progression. In this review we discuss both the activators and the inhibitors of IL-17 signal transduction, and also the physiological implications of these events. We highlight the surprisingly diverse means by which these regulators control expression of IL-17-dependent inflammatory genes, as well as the major target cells that respond to IL-17 signaling.

Intestinal commensal bacteria mediate lung mucosal immunity and promote resistance of newborn mice to infection

Immature mucosal defenses contribute to increased susceptibility of newborn infants to pathogens. Sparse knowledge of age-dependent changes in mucosal immunity has hampered improvements in neonatal morbidity because of infections. We report that exposure of neonatal mice to commensal bacteria immediately after birth is required for a robust host defense against bacterial pneumonia, the leading cause of death in newborn infants. This crucial window was characterized by an abrupt influx of interleukin-22 (IL-22)-producing group 3 innate lymphoid cells (IL-22+ILC3) into the lungs of newborn mice. This influx was dependent on sensing of commensal bacteria by intestinal mucosal dendritic cells. Disruption of postnatal commensal colonization or selective depletion of dendritic cells interrupted the migratory program of lung IL-22+ILC3 and made the newborn mice more susceptible to pneumonia, which was reversed by transfer of commensal bacteria after birth. Thus, the resistance of newborn mice to pneumonia relied on commensal bacteria-directed ILC3 influx into the lungs, which mediated IL-22-dependent host resistance to pneumonia during this developmental window. These data establish that postnatal colonization by intestinal commensal bacteria is pivotal in the development of the lung defenses of newborns.

IL-17: overview and role in oral immunity and microbiome

Interleukin-17 (IL-17) is a multifaceted cytokine with diverse roles in both immune protection and also immunopathology. IL-17 has a well-recognized role in immune surveillance at mucosal and barrier surfaces, but also has been increasingly implicated as a driver of immunopathology in settings of autoimmunity and chronic inflammation. The current review introduces basic aspects of IL-17 biology and examines the protective and pathogenic roles of IL-17 with a focus on oral mucosal immunity and inflammation. Specific emphasis is given to the role of the IL-17 response as a catalyst in 'shaping the microbiome at the oral barrier'.

Designing the angiogenic inhibitor for brain tumor via disruption of VEGF and IL17A expression

Glioblastoma multiforme is a highly malignant, heterogenic, and drug resistant tumor. The blood-brain barrier (BBB), systemic cytotoxicity, and limited specificity are the main obstacles in designing brain tumor drugs. In this study a computational approach was used to design brain tumor drugs that could downregulate VEGF and IL17A in glioblastoma multiforme type four. Computational screening tools were used to evaluate potential candidates for antiangiogenic activity, target binding, BBB permeability, and ADME physicochemical properties. Additionally, in vitro cytotoxicity, migration, invasion, tube formation, apoptosis, ROS and ELISA assays were conducted for molecule 6 that was deemed most likely to succeed. The efflux ratio of membrane permeability and calculated docking scores of permeability to glycoproteins (P-gps) were used to determine the BBB permeability of the molecules. The results showed BBB permeation for molecule 6, with the predicted efficiency of 0.55kcal/mol and binding affinity of -37kj/mol corresponding to an experimental efflux ratio of 0.625 and predicted -15kj/mol of binding affinity for P-gps. Molecule 6 significantly affected the angiogenesis pathways by 2-fold downregulation of IL17A and VEGF through inactivation of active sites of HSP90 (predicted binding: -37kj/mol, predicted efficiency: 0.55kcal/mol) and p23 (predicted binding: 12kj/mol, predicted efficiency: 0.17kcal/mol) chaperon proteins. Additionally, molecule 6 activated the 17.38% relative fold of ROS level at 18.3μg/mL and upregulated the caspase which lead the potential synergistic apoptosis through the antiangiogenic activity of molecule 6 and thereby the highly efficacious anticancer upshot. The results indicate that the binding of the molecules to the therapeutic target is not essential to produce a lethal effect on cancer cells of the brain and that antiangiogenic efficiency is much more important.

Intestinal Interleukin-17 Receptor Signaling Mediates Reciprocal Control of the Gut Microbiota and Autoimmune Inflammation

Interleukin-17 (IL-17) and IL-17 receptor (IL-17R) signaling are essential for regulating mucosal host defense against many invading pathogens. Commensal bacteria, especially segmented filamentous bacteria (SFB), are a crucial factor that drives T helper 17 (Th17) cell development in the gastrointestinal tract. In this study, we demonstrate that Th17 cells controlled SFB burden. Disruption of IL-17R signaling in the enteric epithelium resulted in SFB dysbiosis due to reduced expression of α-defensins, Pigr, and Nox1. When subjected to experimental autoimmune encephalomyelitis, IL-17R-signaling-deficient mice demonstrated earlier disease onset and worsened severity that was associated with increased intestinal Csf2 expression and elevated systemic GM-CSF cytokine concentrations. Conditional deletion of IL-17R in the enteric epithelium demonstrated that there was a reciprocal relationship between the gut microbiota and enteric IL-17R signaling that controlled dysbiosis, constrained Th17 cell development, and regulated the susceptibility to autoimmune inflammation.

[Autoimmune reactions in psoriasis : Spotlight]

BACKGROUND

Psoriasis is a human leukocyte antigen (HLA)-associated T‑cell-mediated disorder.

OBJECTIVES

The role of the main psoriasis risk allele HLA-C*06:02 in disease manifestation and the mechanisms which activate the pathogenic T‑cell response in the skin of psoriasis patients remained elusive.

MATERIALS AND METHODS

Key to the immune pathogenesis of psoriasis was the analysis of the specificity of the infiltrating lesional psoriatic CD8(+) T cells

RESULTS AND CONCLUSION

Analyses of the lesional psoriatic T‑cell reactivity demonstrate that psoriasis is an autoimmune disease. It is based on an autoimmune response against melanocytes which is preferentially mediated by HLA-C*06:02 through autoantigen presentation. Here we discuss the mechanisms of this autoimmune response in the context of the polygenic psoriatic predisposition.

The roles and functional mechanisms of interleukin-17 family cytokines in mucosal immunity

The mucosal immune system serves as our front-line defense against pathogens. It also tightly maintains immune tolerance to self-symbiotic bacteria, which are usually called commensals. Sensing both types of microorganisms is modulated by signalling primarily through various pattern-recognition receptors (PRRs) on barrier epithelial cells or immune cells. After sensing, proinflammatory molecules such as cytokines are released by these cells to mediate either defensive or tolerant responses. The interleukin-17 (IL-17) family members belong to a newly characterized cytokine subset that is critical for the maintenance of mucosal homeostasis. In this review, we will summarize recent progress on the diverse functions and signals of this family of cytokines at different mucosal edges.