Interleukin-17C promotes Th17 cell responses and autoimmune disease via interleukin-17 receptor E

Fragile Guts Make Fragile Brains: Intestinal Epithelial Nrf2 Deficiency Exacerbates Neurotoxicity Induced by Polystyrene Nanoplastics

Oral ingestion is the primary route for human exposure to nanoplastics, making the gastrointestinal tract one of the first and most impacted organs. Given the presence of the gut-brain axis, a crucial concern arises regarding the potential impact of intestinal damage on the neurotoxic effects of nanoplastics (NPs). The intricate mechanisms underlying NP-induced neurotoxicity through the microbiome-gut-brain axis necessitate further investigation. To address this, we used mice specifically engineered with nuclear factor erythroid-derived 2-related factor 2 (Nrf2) deficiency in their intestines, a strain whose intestines are particularly susceptible to polystyrene NPs (PS-NPs). We conducted a 28-day repeated-dose oral toxicity study with 2.5 and 250 mg/kg of 50 nm PS-NPs in these mice. Our study delineated how PS-NP exposure caused gut microbiota dysbiosis, characterized by Mycoplasma and Coriobacteriaceae proliferation, resulting in increased levels of interleukin 17C (IL-17C) production in the intestines. The surplus IL-17C permeated the brain via the bloodstream, triggering inflammation and brain damage. Our investigation elucidated a direct correlation between intestinal health and neurological outcomes in the context of PS-NP exposure. Susceptible mice with fragile guts exhibited heightened neurotoxicity induced by PS-NPs. This phenomenon was attributed to the elevated abundance of microbiota associated with IL-17C production in the intestines of these mice, such as Mesorhizobium and Lwoffii, provoked by PS-NPs. Neurotoxicity was alleviated by in vivo treatment with anti-IL-17C-neutralizing antibodies or antibiotics. These findings advanced our comprehension of the regulatory mechanisms governing the gut-brain axis in PS-NP-induced neurotoxicity and underscored the critical importance of maintaining intestinal health to mitigate the neurotoxic effects of PS-NPs.

Endometrial senescence is mediated by interleukin 17 receptor B signaling

BACKGROUND

We previously identified Il17RB, a member of the IL17 superfamily, as a candidate marker gene for endometrial aging. While IL17RB has been linked to inflammation and malignancies in several organ systems, its function in the endometrium has not been investigated and is thus poorly understood. In the present study, we performed a functional analysis of this receptor with the aim of determining the effects of its age-associated overexpression on the uterine environment.

METHODS

We analyzed IL17RB-related signaling pathways and downstream gene expression in an immortalized human endometrial glandular epithelial cell line ("hEM") forced to express the receptor via lentiviral transduction ("IL17RB-hEM"). We also prepared endometrial organoids from human endometrial tissue sourced from hysterectomy patients ("patient-derived EOs") and exposed them to cytokines that are upregulated by IL17RB expression to investigate changes in organoid-forming capacity and senescence markers. We analyzed RNA-seq data (GEO accession number GSE132886) from our previous study to identify the signaling pathways associated with altered IL17RB expression. We also analyzed the effects of the JNK pathway on organoid-forming capacity.

RESULTS

Stimulation with interleukin 17B enhanced the NF-κB pathway in IL17RB-hEM, resulting in significantly elevated expression of the genes encoding the senescence associated secretory phenotype (SASP) factors IL6, IL8, and IL1β. Of these cytokines, IL1β inhibited endometrial organoid growth. Bioinformatics analysis showed that the JNK signaling pathway was associated with age-related variation in IL17RB expression. When IL17RB-positive cells were cultured in the presence of IL17B, their organoid-forming capacity was slightly but non-significantly lower than in unexposed IL17RB-positive cells, but when IL17B was paired with a JNK inhibitor (SP600125), it was restored to control levels. Further, IL1β exposure significantly reduced organoid-forming capacity and increased p21 expression in endometrial organoids relative to non-exposure (control), but when IL1β was paired with SP600125, both indicators were restored to levels comparable to the control condition.

CONCLUSIONS

We have revealed an association between IL17RB, whose expression increases in the endometrial glandular epithelium with advancing age, and cellular senescence. Using human endometrial organoids as in vitro model, we found that IL1β inhibits cell proliferation and leads to endometrial senescence via the JNK pathway.

Multiarray screening identifies plasma proteins associated with Th17 cell differentiation and viral defense in coincident asthma and obesity

BACKGROUND

The immunological mechanisms behind the clinical association between asthma and obesity in adolescence are not fully understood. This study aimed to find new plasma protein biomarkers associated specifically with coincident asthma and obesity in adolescents.

METHODS

This was a cross-sectional study in children and adolescents 10-19 years old (N = 390). Relative plasma concentrations of 113 protein biomarkers related to inflammation and immune response were determined by proximity extension assay (Target 96; Olink, Uppsala, Sweden). Differences in protein concentrations between healthy controls (n = 84), subjects with asthma (n = 138), subjects with obesity (n = 107), and subjects with both asthma and obesity (AO; n = 58) were analyzed by ANCOVA, adjusting for age and sex, and in a separate model adjusting also for the sum of specific IgE antibody concentrations to a mix of food allergens (fx5) and aeroallergens (Phadiatop). Proteins elevated in the AO group but not in the obesity or asthma groups were considered specifically elevated in asthma and obesity.

RESULTS

Five proteins were elevated specifically in the AO group compared to controls (here sorted from largest to smallest effect of asthma and obesity combined): CCL8, IL-33, IL-17C, FGF-23, and CLEC7A. The effects of adjusting also for specific IgE were small but IL-33, IL-17C, and FGF-23 were no longer statistically significant.

CONCLUSION

We identified several new potential plasma biomarkers specifically elevated in coincident asthma and obesity in adolescents. Four of the proteins, CCL8, IL-33, IL-17C, and CLEC7A, have previously been associated with viral mucosal host defense and Th17 cell differentiation.

Interleukin-17 directly stimulates tumor infiltrating Tregs to prevent cancer development

Background

Interleukin-17 (IL-17) family cytokines promote protective inflammation for pathogen resistance, but also facilitate autoimmunity and tumor development. A direct signal of IL-17 to regulatory T cells (Tregs) has not been reported and may help explain these dichotomous responses.

Methods

We generated a conditional knockout of Il17ra in Tregs by crossing Foxp3-YFP-Cre mice to Il17ra-flox mice (Il17ra ΔTreg mice). Subsequently, we adoptively transferred bone marrow cells from Il17ra ΔTreg mice to a mouse model of sporadic colorectal cancer (Cdx2-Cre +/Apc F/+), to selectively ablate IL-17 direct signaling on Tregs in colorectal cancer. Single cell RNA sequencing and bulk RNA sequencing were performed on purified Tregs from mouse colorectal tumors, and compared to those of human tumor infiltrating Treg cells.

Results

IL-17 Receptor A (IL-17RA) is expressed in Tregs that reside in mouse mesenteric lymph nodes and colon tumors. Ablation of IL-17RA, specifically in Tregs, resulted in increased Th17 cells, and exacerbated tumor development. Mechanistically, tumor-infiltrating Tregs exhibit a unique gene signature that is linked to their activation, maturation, and suppression function, and this signature is in part supported by the direct signaling of IL-17 to Tregs. To study pathways of Treg programming, we found that loss of IL-17RA in tumor Tregs resulted in reduced RNA splicing, and downregulation of several RNA binding proteins that are known to regulate alternative splicing and promote Treg function.

Conclusion

IL-17 directly signals to Tregs and promotes their maturation and function. This signaling pathway constitutes a negative feedback loop that controls cancer-promoting inflammation in CRC.

The role of interleukin-36 in health and disease states

The interleukin (IL)-1 superfamily upregulates immune responses and maintains homeostasis between the innate and adaptive immune systems. Within the IL-1 superfamily, IL-36 plays a pivotal role in both innate and adaptive immune responses. Of the four IL-36 isoforms, three have agonist activity (IL-36α, IL-36β, IL-36γ) and the fourth has antagonist activity (IL-36 receptor antagonist [IL-36Ra]). All IL-36 isoforms bind to the IL-36 receptor (IL-36R). Binding of IL-36α/β/γ to the IL-36R recruits the IL-1 receptor accessory protein (IL-1RAcP) and activates downstream signalling pathways mediated by nuclear transcription factor kappa B and mitogen-activated protein kinase signalling pathways. Antagonist binding of IL-36Ra to IL-36R inhibits recruitment of IL-1RAcP, blocking downstream signalling pathways. Changes in the balance within the IL-36 cytokine family can lead to uncontrolled inflammatory responses throughout the body. As such, IL-36 has been implicated in numerous inflammatory diseases, notably a type of pustular psoriasis called generalized pustular psoriasis (GPP), a chronic, rare, potentially life-threatening, multisystemic skin disease characterised by recurrent fever and extensive sterile pustules. In GPP, IL-36 is central to disease pathogenesis, and the prevention of IL-36-mediated signalling can improve clinical outcomes. In this review, we summarize the literature describing the biological functions of the IL-36 pathway. We also consider the evidence for uncontrolled activation of the IL-36 pathway in a wide range of skin (e.g., plaque psoriasis, pustular psoriasis, hidradenitis suppurativa, acne, Netherton syndrome, atopic dermatitis and pyoderma gangrenosum), lung (e.g., idiopathic pulmonary fibrosis), gut (e.g., intestinal fibrosis, inflammatory bowel disease and Hirschsprung's disease), kidney (e.g., renal tubulointerstitial lesions) and infectious diseases caused by a variety of pathogens (e.g., COVID-19; Mycobacterium tuberculosis, Pseudomonas aeruginosa, Streptococcus pneumoniae infections), as well as in cancer. We also consider how targeting the IL-36 signalling pathway could be used in treating inflammatory disease states.

IL-17C is a driver of damaging inflammation during Neisseria gonorrhoeae infection of human Fallopian tube

The human pathogen Neisseria gonorrhoeae ascends into the upper female reproductive tract to cause damaging inflammation within the Fallopian tubes and pelvic inflammatory disease (PID), increasing the risk of infertility and ectopic pregnancy. The loss of ciliated cells from the epithelium is thought to be both a consequence of inflammation and a cause of adverse sequelae. However, the links between infection, inflammation, and ciliated cell extrusion remain unresolved. With the use of ex vivo cultures of human Fallopian tube paired with RNA sequencing we defined the tissue response to gonococcal challenge, identifying cytokine, chemokine, cell adhesion, and apoptosis related transcripts not previously recognized as potentiators of gonococcal PID. Unexpectedly, IL-17C was one of the most highly induced genes. Yet, this cytokine has no previous association with gonococcal infection nor pelvic inflammatory disease and thus it was selected for further characterization. We show that human Fallopian tubes express the IL-17C receptor on the epithelial surface and that treatment with purified IL-17C induces pro-inflammatory cytokine secretion in addition to sloughing of the epithelium and generalized tissue damage. These results demonstrate a previously unrecognized but critical role of IL-17C in the damaging inflammation induced by gonococci in a human explant model of PID.

SCFFBXW11 Complex Targets Interleukin-17 Receptor A for Ubiquitin-Proteasome-Mediated Degradation

Interleukin-17 (IL-17) is a pro-inflammatory cytokine that participates in innate and adaptive immune responses and plays an important role in host defense, autoimmune diseases, tissue regeneration, metabolic regulation, and tumor progression. Post-translational modifications (PTMs) are crucial for protein function, stability, cellular localization, cellular transduction, and cell death. However, PTMs of IL-17 receptor A (IL-17RA) have not been investigated. Here, we show that human IL-17RA was targeted by F-box and WD repeat domain-containing 11 (FBXW11) for ubiquitination, followed by proteasome-mediated degradation. We used bioinformatics tools and biochemical techniques to determine that FBXW11 ubiquitinated IL-17RA through a lysine 27-linked polyubiquitin chain, targeting IL-17RA for proteasomal degradation. Domain 665-804 of IL-17RA was critical for interaction with FBXW11 and subsequent ubiquitination. Our study demonstrates that FBXW11 regulates IL-17 signaling pathways at the IL-17RA level.

Circulatory Inflammatory Proteins as Early Diagnostic Biomarkers for Invasive Aspergillosis in Patients with Hematologic Malignancies-an Exploratory Study

OBJECTIVES

Invasive aspergillosis (IA) is a major cause of mortality in immunocompromised patients and it is difficult to diagnose because of the lack of reliable highly sensitive diagnostics. We aimed to identify circulating immunological markers that could be useful for an early diagnosis of IA.

METHODS

We collected longitudinally serum samples from 33 cases with probable/proven IA and two matched control cohorts without IA (one with microbiological and clinical evidence of bacterial or viral non-fungal pneumonia and one without evidence of infection, all matched for neutropenia, primary underlying disease, and receipt of corticosteroids/other immunosuppressants) at a tertiary university hospital. In addition, samples from an independent cohort (n = 20 cases of proven/probable IA and 20 matched controls without infection) were obtained. A panel of 92 circulating proteins involved in inflammation was measured by proximity extension assay. A random forest model was used to predict the development of IA using biomarkers measured before diagnosis.

RESULTS

While no significant differences were observed between IA cases and infected controls, concentrations of 30 inflammatory biomarkers were different between cases and non-infected controls, of which nine were independently replicated: PD-L1, MMP-10, Interleukin(IL)-10, IL-15RA, IL-18, IL-18R1, CDCP1, CCL19 and IL-17C. From the differential abundance analysis of serum samples collected more than 10 days before diagnosis and at diagnosis, increased IL-17C concentrations in IA patients were replicated in the independent cohort.

CONCLUSIONS

An increased circulating concentration of IL-17C was detected both in the discovery and independent cohort, both at the time of diagnosis and in samples 10 days before the diagnosis of IA, suggesting it should be evaluated further as potential (early) biomarker of infection.

Human Fallopian Tube-Derived Organoids with TP53 and RAD51D Mutations Recapitulate an Early Stage High-Grade Serous Ovarian Cancer Phenotype In Vitro

RAD51D mutations have been implicated in the transformation of normal fallopian tube epithelial (FTE) cells into high-grade serous ovarian cancer (HGSOC), one of the most prevalent and aggressive gynecologic malignancies. Currently, no suitable model exists to elucidate the role of RAD51D in disease initiation and progression. Here, we established organoids from primary human FTE and introduced TP53 as well as RAD51D knockdown to enable the exploration of their mutational impact on FTE lesion generation. We observed that TP53 deletion rescued the adverse effects of RAD51D deletion on the proliferation, stemness, senescence, and apoptosis of FTE organoids. RAD51D deletion impaired the homologous recombination (HR) function and induced G2/M phase arrest, whereas concurrent TP53 deletion mitigated G0/G1 phase arrest and boosted DNA replication when combined with RAD51D mutation. The co-deletion of TP53 and RAD51D downregulated cilia assembly, development, and motility, but upregulated multiple HGSOC-associated pathways, including the IL-17 signaling pathway. IL-17A treatment significantly improved cell viability. TP53 and RAD51D co-deleted organoids exhibited heightened sensitivity to platinum, poly-ADP ribose polymerase inhibitors (PARPi), and cell cycle-related medication. In summary, our research highlighted the use of FTE organoids with RAD51D mutations as an invaluable in vitro platform for the early detection of carcinogenesis, mechanistic exploration, and drug screening.

Anti-gout and Urate-lowering Potentials of Curcumin: A Review from Bench to Beside

BACKGROUND

Gouty arthritis is a complex form of inflammatory arthritis, triggered by the sedimentation of monosodium urate crystals in periarticular tissues, synovial joints, and other sites in the body. Curcumin is a natural polyphenol compound, isolated from the rhizome of the plant Curcuma longa, possessing countless physiological features, including antioxidant, anti-inflammatory, and anti-rheumatic qualities.

OBJECTIVE

This study aimed to discuss the beneficial impacts of curcumin and its mechanism in treating gout disease.

METHODS

Ten English and Persian databases were used to conduct a thorough literature search. Studies examining the anti-gouty arthritis effects of curcumin and meeting the inclusion criteria were included.

RESULTS

According to the studies, curcumin has shown xanthine oxidase and urate transporter- 1 inhibitory properties, uric acid inhibitory characteristics, and antioxidant and anti- inflammatory effects. However, some articles found no prominent reduction in uric acid levels.

CONCLUSION

In this review, we emphasized the potency of curcumin and its compounds against gouty arthritis. Despite the potency, we suggest an additional well-designed evaluation of curcumin, before its therapeutic effectiveness is completely approved as an antigouty arthritis agent.

Physiological roles of human interleukin-17 family

Interleukin-17 s (IL-17s) are well-known proinflammatory cytokines, and their antagonists perform excellently in the treatment of inflammatory skin diseases such as psoriasis. However, their physiological functions have not been given sufficient attention by clinicians. IL-17s can protect the host from extracellular pathogens, maintain epithelial integrity, regulate cognitive processes and modulate adipocyte activity through distinct mechanisms. Here, we present a systematic review concerning the physiological functions of IL-17s. Our goal is not to negate the therapeutic effect of IL-17 antagonists, but to ensure their safe use and reasonably explain the possible adverse events that may occur in their application.

BHLHE40 drives protective polyfunctional CD4 T cell differentiation in the female reproductive tract against Chlamydia

The protein basic helix-loop-helix family member e40 (BHLHE40) is a transcription factor recently emerged as a key regulator of host immunity to infections, autoimmune diseases and cancer. In this study, we investigated the role of Bhlhe40 in protective T cell responses to the intracellular bacterium Chlamydia in the female reproductive tract (FRT). Mice deficient in Bhlhe40 exhibited severe defects in their ability to control Chlamydia muridarum shedding from the FRT. The heightened bacterial burdens in Bhlhe40-/- mice correlated with a marked increase in IL-10-producing T regulatory type 1 (Tr1) cells and decreased polyfunctional CD4 T cells co-producing IFN-γ, IL-17A and GM-CSF. Genetic ablation of IL-10 or functional blockade of IL-10R increased CD4 T cell polyfunctionality and partially rescued the defects in bacterial control in Bhlhe40-/- mice. Using single-cell RNA sequencing coupled with TCR profiling, we detected a significant enrichment of stem-like T cell signatures in Bhlhe40-deficient CD4 T cells, whereas WT CD4 T cells were further down on the differentiation trajectory with distinct effector functions beyond IFN-γ production by Th1 cells. Altogether, we identified Bhlhe40 as a key molecular driver of CD4 T cell differentiation and polyfunctional responses in the FRT against Chlamydia.

Targeting Interleukin-17 as a Novel Treatment Option for Fibrotic Diseases

Fibrosis is the end result of persistent inflammatory responses induced by a variety of stimuli, including chronic infections, autoimmune reactions, and tissue injury. Fibrotic diseases affect all vital organs and are characterized by a high rate of morbidity and mortality in the developed world. Until recently, there were no approved antifibrotic therapies. In recent years, high levels of interleukin-17 (IL-17) have been associated with chronic inflammatory diseases with fibrotic complications that culminate in organ failure. In this review, we provide an update on the role of IL-17 in fibrotic diseases, with particular attention to the most recent lines of research in the therapeutic field represented by the epigenetic mechanisms that control IL-17 levels in fibrosis. A better knowledge of the IL-17 signaling pathway implications in fibrosis could design new strategies for therapeutic benefits.

Predictive factors of atopic-like dermatitis induced by IL-17A inhibitors in patients with psoriasis: A 2-year follow-up study

BACKGROUND

Atopic-like dermatitis (ALD) is a common side effect of interleukin-17A (IL-17A) inhibitors.

OBJECTIVE

To determine the prevalence, risk factors, outcomes and treatment of ALD in a cohort of psoriasis patients treated with IL-17A inhibitors.

METHODS

This retrospective study included 226 psoriasis patients treated with an IL-17A inhibitor in our dermatology department between July 2020 and July 2022. The patients were reviewed over 2 years. A logistic regression model in rare events data (relogit) was used to predict the risk factors for ALD.

RESULTS

Of the 226 patients, 14 had ALD. Data including age, body mass index, IL-17A inhibitor use, personal and family history of atopic disease, pet ownership history, and immunoglobulin E (IgE) levels were analysed using the relogit regression model. It indicated a personal history of atopic disease (odd ratio [OR] 27.830, 95% confidence interval [CI] 3.801-203.770; p = 0.001) and elevated IgE levels (OR 5.867, 95% CI 1.131-30.434; p = 0.035) as independent predictors of incident ALD. In one patient, anti-IL-17A therapy was discontinued, and treatment was switched to tofacitinib. Thirteen patients who continued with IL-17A inhibitor were treated with topical therapy and/or antihistamines, and their ALD was partially or completely resolved.

CONCLUSION

In this study, the incidence rate of ALD was 6.19%. Elevated IgE levels and a personal history of atopic disease were found to be the risk factors for ALD. Our study findings suggest that treatment should be provided based on the severity of psoriasis and incident ALD. Prior to treatment, psoriasis patients who have the risk factors for ALD should be informed of the possible development of ALD, and alternative psoriatic therapeutic options should be considered if severe ALD develops.

BHLHE40 drives protective polyfunctional CD4 T cell differentiation in the female reproductive tract against Chlamydia

The protein basic helix-loop-helix family member e40 (BHLHE40) is a transcription factor recently emerged as a key regulator of host immunity to infections, autoimmune diseases and cancer. In this study, we investigated the role of Bhlhe40 in protective T cell responses to the intracellular bacterium Chlamydia in the female reproductive tract (FRT). Mice deficient in Bhlhe40 exhibited severe defects in their ability to control Chlamydia muridarum shedding from the FRT. The heightened bacterial burdens in Bhlhe40-/- mice correlated with a marked increase in IL-10-producing T regulatory type 1 (Tr1) cells and decreased polyfunctional CD4 T cells co-producing IFN-γ, IL-17A and GM-CSF. Genetic ablation of IL-10 or functional blockade of IL-10R increased CD4 T cell polyfunctionality and partially rescued the defects in bacterial control in Bhlhe40-/- mice. Using single-cell RNA sequencing coupled with TCR profiling, we detected a significant enrichment of stem-like T cell signatures in Bhlhe40-deficient CD4 T cells, whereas WT CD4 T cells were further down on the differentiation trajectory with distinct effector functions beyond IFN-γ production by Th1 cells. Altogether, we identified Bhlhe40 as a key molecular driver of CD4 T cell differentiation and polyfunctional responses in the FRT against Chlamydia.

PepScaf: Harnessing Machine Learning with In Vitro Selection toward De Novo Macrocyclic Peptides against IL-17C/IL-17RE Interaction

The combination of library-based screening and artificial intelligence (AI) has been accelerating the discovery and optimization of hit ligands. However, the potential of AI to assist in de novo macrocyclic peptide ligand discovery has yet to be fully explored. In this study, an integrated AI framework called PepScaf was developed to extract the critical scaffold relative to bioactivity based on a vast dataset from an initial in vitro selection campaign against a model protein target, interleukin-17C (IL-17C). Taking the generated scaffold, a focused macrocyclic peptide library was rationally constructed to target IL-17C, yielding over 20 potent peptides that effectively inhibited IL-17C/IL-17RE interaction. Notably, the top two peptides displayed exceptional potency with IC50 values of 1.4 nM. This approach presents a viable methodology for more efficient macrocyclic peptide discovery, offering potential time and cost savings. Additionally, this is also the first report regarding the discovery of macrocyclic peptides against IL-17C/IL-17RE interaction.

Brodalumab in the Treatment of Plaque Psoriasis Localized in Difficult-to-Treat Areas: A Narrative Review

INTRODUCTION

Psoriasis is a common chronic, immune-mediated, inflammatory skin disease that in certain localization results difficult to treat. Psoriatic lesions in difficult-to-treat areas might be hardly managed as no standardized therapeutic approach and the application of topical treatments might have great limitations. Systemic agents, including biologic therapies, have been proven effective in treating this subgroup of patients. In particular, current evidence has shown beneficial effects with the use of brodalumab, a fully human IgG2 monoclonal antibody antagonizing the IL-17 receptor A subunit (IL-17RA).

OBJECTIVES

The aim of this narrative review was to collect published data about efficacy and safety of brodalumab in the treatment of psoriasis occurring in difficult-to-treat areas.

METHODS

Data on brodalumab effectiveness and safety deriving from both trials and real-world setting that had been published in the last 15 years were collected for this review, together with clinical findings issued during international meetings.

RESULTS

In phase 3 trials, brodalumab demonstrated to be effective in promoting a rapid response in scalp psoriasis as well as in generalized pustular psoriasis and erythrodermic psoriasis. Nail psoriasis demonstrated marked clinical improvement after treatment with brodalumab. Amelioration of palmoplantar psoriasis was also described in brodalumab-treated patients. Various retrospective real-world studies reported a complete clearance of psoriatic lesions in difficult-to-treat areas, including genitalia, through short-term brodalumab treatment.

CONCLUSIONS

Brodalumab, combining rapid and sustained efficacy with a favorable safety profile, may be a valid therapeutic option for severe variants of psoriasis as well as for psoriasis localized in difficult-to-treat areas.

Identification and Validation of Hub Immune-Related Genes in Non-Alcoholic Fatty Liver Disease

Background

Nonalcoholic fatty liver disease (NAFLD) is the most common progressive liver disease worldwide. It can cause liver cancer and possibly death. Abnormal immune infiltration is involved in the progression of NAFLD. The aim of this study was to identify and validate the hub immune-related genes in NAFLD.

Methods

Microarray data were downloaded from Gene Expression Omnibus, and immune-related differentially expressed genes (IRDEGs) were obtained. A protein-protein interaction network was used to further screen. The diagnostic value of the IRDEGs was evaluated by receiver operating characteristic curves. Differences in immune infiltration levels were analyzed using single-sample gene set enrichment analysis. Hub IRDEGs were identified by correlation analysis with immune infiltration levels. Finally, molecular experiments were used to confirm the expression of the hub IRDEGs and explore their roles in NAFLD.

Results

We obtained 18 IRDEGs. Five hub genes were further identified by protein-protein interaction network, receiver operating characteristic curves and correlation analysis: AQP9, BACH2, CD4, IL17RE and S100A9. Based on functional enrichment analysis, the hub genes were enriched primarily in many immune-related pathways. In NAFLD, AQP9, CD4, and IL17RE expression was significantly reduced, whereas BACH2 and S100A9 expression was elevated. PCR, oil red O staining and triglyceride detection revealed that the knock-down of BACH2 and S100A9 reduced lipid accumulation in NAFLD cells.

Conclusion

This study provided insight into the profile of immune infiltration underlying NAFLD and identified AQP9, BACH2, CD4, IL17RE and S100A9 as ancillary diagnostic indicators of NAFLD. And BACH2 and S100A9 might be therapeutic targets for NAFLD.

IL-17C neutralization protects the kidney against acute injury and chronic injury

BACKGROUND

Interleukin-17C (IL-17C), a member of the IL-17 cytokine family, plays a pathogenic role in kidney diseases. Our previous studies have shown that pre-administration of IL-17C neutralizing antibody attenuated acute kidney injury (AKI, a common acute inflammation associated renal disease). In this study, we explored whether post-ischemia reperfusion (IR) of IL-17C blockade has therapeutic effects on AKI and whether IL-17C is involved in the pathogenesis of diabetic nephropathy (DN), a major type of chronic inflammation-associated kidney disease.

METHODS

12-week-old male C57BL/6JGpt mice were treated with IL-17C neutralizing antibody or normal IgG control antibody at 3 h after reperfusion. Renal injury, inflammation, and oxidative stress were assessed. Additionally, we examined renal IL-17C expression in patients with DN and db/db mice and evaluated albuminuria, mesangial matrix accumulation and podocyte loss in db/db mice with IL-17C neutralization. Knockdown of NF-κB p65 using siRNA, and blocking Hypoxia-inducible factor-1α (HIF-1α) using YC-1 in mice and HIF-1α Decoy in HK2 cells were investigated to explore the possible signaling pathway involved in IL-17C regulation.

FINDINGS

We found that delayed IL-17C neutralization had similar reno-protective effects on renal ischemia-reperfusion injury (IRI). Additionally, renal IL-17C expression was increased in patients with DN and db/db mice, while IL-17C blockade significantly attenuated DN, accompanied with blunted albuminuria, mesangial matrix accumulation, and podocyte loss. Moreover, IL-17C neutralization significantly repressed the expression of downstream pro-inflammatory cytokines, inflammatory cell infiltration, and Th17/IL-17A activation both in mice with renal IRI and DN. Mechanistical studies demonstrated that hypoxia or high glucose-induced IL-17C up-regulation was predominantly mediated by NF-κB pathway.

INTERPRETATION

IL-17C participates in the pathogenesis of AKI and DN and inhibition of IL-17C shows potential as a therapeutic strategy for AKI and DN.

FUNDING

The National Natural Science Foundation of China (81770741, 81700601 and 81870504).

Tofacitinib for the Treatment of Psoriasiform Dermatitis Caused by IL-17 Inhibitors: A Case Report

Psoriasis is a recurring systemic disease that can be treated with biologics to some effect. However, precisely targeting inflammatory mediators may disrupt immune system homeostasis and lead to new conditions. Here, we report a case of psoriasiform dermatitis (PsoD) caused by IL-17 inhibitors (IL-17i) namely secukinumab treatment for psoriasis. This case proposes an effective use of Janus kinase inhibitor (JAKi) tofacitinib to confront lesions induced by IL-17i. This is the first case report of PsoD caused by secukinumab treated with tofacitinib.

Exploiting antifungal immunity in the clinical context

The continuous expansion of immunocompromised patient populations at-risk for developing life-threatening opportunistic fungal infections in recent decades has helped develop a deeper understanding of antifungal host defenses, which has provided the foundation for eventually devising immune-based targeted interventions in the clinic. This review outlines how genetic variation in certain immune pathway-related genes may contribute to the observed clinical variability in the risk of acquisition and/or severity of fungal infections and how immunogenetic-based patient stratification may enable the eventual development of personalized strategies for antifungal prophylaxis and/or vaccination. Moreover, this review synthesizes the emerging cytokine-based, cell-based, and other immunotherapeutic strategies that have shown promise as adjunctive therapies for boosting or modulating tissue-specific antifungal immune responses in the context of opportunistic fungal infections.

The Interleukine-17 Cytokine Family: Role in Development and Progression of Spondyloarthritis, Current and Potential Therapeutic Inhibitors

Spondyloarthritis (SpA) encompasses a group of chronic inflammatory rheumatic diseases with a predilection for the spinal and sacroiliac joints, which include axial spondyloarthritis, psoriatic arthritis, reactive arthritis, arthritis associated with chronic inflammatory bowel disease, and undifferentiated spondyloarthritis. The prevalence of SpA in the population varies from 0.5 to 2%, most commonly affecting young people. Spondyloarthritis pathogenesis is related to the hyperproduction of proinflammatory cytokines (TNFα, IL-17A, IL-23, etc.). IL-17A plays a key role in the pathogenesis of spondyloarthritis (inflammation maintenance, syndesmophites formation and radiographic progression, enthesites and anterior uveitis development, etc.). Targeted anti-IL17 therapies have established themselves as the most efficient therapies in SpA treatment. The present review summarizes literature data on the role of the IL-17 family in the pathogenesis of SpA and analyzes existing therapeutic strategies for IL-17 suppression with monoclonal antibodies and Janus kinase inhibitors. We also consider alternative targeted strategies, such as the use of other small-molecule inhibitors, therapeutic nucleic acids, or affibodies. We discuss advantages and pitfalls of these approaches and the future prospects of each method.

IL17RB and IL17REL Expression Are Associated with Improved Prognosis in HPV-Infected Head and Neck Squamous Cell Carcinomas

Changes in the cellular secretome are implicated in virus infection, malignancy, and anti-tumor immunity. We analyzed the association between transcriptional signatures (TS) from 24 different immune and stromal cell types on the prognosis of HPV-infected and HPV-free head and neck squamous carcinoma (HNSCC) patients from The Cancer Genome Atlas (TCGA) cohort. We found that HPV-positive HNSCC patients have tumors with elevated immune cell TS and improved prognosis, which was specifically associated with an increased tumor abundance of memory B and activated natural killer (NK) cell TS, compared to HPV-free HNSCC patients. HPV-infected patients upregulated many transcripts encoding secreted factors, such as growth factors, hormones, chemokines and cytokines, and their cognate receptors. Analysis of secretome transcripts and cognate receptors revealed that tumor expression of IL17RB and IL17REL are associated with a higher viral load and memory B and activated NK cell TS, as well as improved prognosis in HPV-infected HNSCC patients. The transcriptional parameters that we describe may be optimized to improve prognosis and risk stratification in the clinic and provide insights into gene and cellular targets that may potentially enhance anti-tumor immunity mediated by NK cells and memory B cells in HPV-infected HNSCC patients.

Eczematized psoriasis - a frequent but often neglected variant of plaque psoriasis

Psoriasis is a common chronic inflammatory skin disease that causes systemic inflammation and severely impacts the patient's quality of life. Several highly effective therapeutics for psoriasis have been approved in recent years. However, in real life, a high proportion of patients either do not experience the clinical improvement observed in clinical trials or develop a secondary loss of efficacy. This may be a result of unrecognized endotypes of psoriasis that need to be characterized in greater depth to enable selection of an appropriate therapy. Eczematized psoriasis, which occurs in approximately 5-10% of patients with psoriasis, is an often-neglected variant of psoriasis. The term "eczematized psoriasis" refers to patients developing psoriasis with similarities to eczema. These patients typically present with severe itching, and skin biopsies often reveal eosinophil granulocytes, serum crusts, or spongiosis, which are frequently observed in eczema. From an immunological perspective, additional signaling pathways that are responsible for eczema reactions might be activated in eczematized psoriasis compared to classical plaque psoriasis. This review summarizes the key clinical, histological, and immunological features of eczematized psoriasis, proposes diagnostic criteria, and evaluates the therapeutic options for eczematized psoriasis.

Therapeutic potential of targeting IL-17 and its receptor signaling in neuroinflammation

T helper 17 cells are thought to significantly contribute to the neuroinflammation process during neurogenerative diseases via their signature cytokine, interleukin (IL)-17. Recently, an emerging key role of IL-17 and its receptors has been documented in inflammatory and autoimmune diseases. The clinical studies conducted on patients with neurodegenerative disease have also shown an increase in IL-17 levels in serum as well as cerebrospinal fluid samples. Therapeutic targeting of either IL-17 receptors or direct IL-17 neutralizing antibodies has shown a promising preclinical and clinical proof of concept for treating chronic autoimmune neurodegenerative diseases such as multiple sclerosis. Thus, IL-17 and its receptors have a central role in regulation of neuroinflammation and can be considered as one of the major therapeutic targets in chronic neuroinflammatory diseases.

Role of Th17 and IL-17 Cytokines on Inflammatory and Auto-immune Diseases

BACKGROUND

The IL-17 (interleukin 17) family consists of six structurally related pro-inflammatory cytokines, namely IL-17A to IL-17F. These cytokines have garnered significant scientific interest due to their pivotal role in the pathogenesis of various diseases. Notably, a specific subset of T-cells expresses IL-17 family members, highlighting their importance in immune responses against microbial infections.

INTRODUCTION

IL-17 cytokines play a critical role in host defense mechanisms by inducing cytokines and chemokines, recruiting neutrophils, modifying T-cell differentiation, and stimulating the production of antimicrobial proteins. Maintaining an appropriate balance of IL-17 is vital for overall health. However, dysregulated production of IL-17A and other members can lead to the pathogenesis of numerous inflammatory and autoimmune diseases.

METHOD

This review provides a comprehensive overview of the IL-17 family and its involvement in several inflammatory and autoimmune diseases. Relevant literature and research studies were analyzed to compile the data presented in this review.

RESULTS

IL-17 cytokines, particularly IL-17A, have been implicated in the development of various inflammatory and autoimmune disorders, including multiple sclerosis, Hashimoto's thyroiditis, systemic lupus erythematosus, pyoderma gangrenosum, autoimmune hepatic disorders, rheumatoid arthritis, psoriasis, psoriatic arthritis, ankylosing spondylitis, osteoarthritis, and graft-versus-host disease. Understanding the role of IL-17 in these diseases is crucial for developing targeted therapeutic strategies.

CONCLUSION

The significant involvement of IL-17 cytokines in inflammatory and autoimmune diseases underscores their potential as therapeutic targets. Current treatments utilizing antibodies against IL-17 cytokines and IL-17RA receptors have shown promise in managing these conditions. This review consolidates the understanding of IL-17 family members and their roles, providing valuable insights for the development of novel immunomodulators to effectively treat inflammatory and autoimmune diseases.

Apolipoprotein A-IV reduced metabolic inflammation in white adipose tissue by inhibiting IKK and JNK signaling in adipocytes

Apolipoprotein A-IV (ApoA-IV) plays a role in satiation and serum lipid transport. In diet-induced obesity (DIO) C57BL/6J mice, ApoA-IV deficiency induced in ApoA-IV-/-knock-out (KO mice) resulted in increased bodyweight, insulin resistance (IR) and plasma free fatty acid (FFA), which was partially reversed by stable ApoA-IV-green fluorescent protein (KO-A4-GFP) transfection in KO mice. DIO KO mice exhibited increased M1 macrophages in epididymal white adipose tissue (eWAT) as well as in the blood. Based on RNA-sequencing analyses, cytokine-cytokine receptor interactions, T cell and B cell receptors, and especially IL-17 and TNF-α, were up-regulated in eWAT of DIO ApoA-IV KO compared with WT mice. Supplemented ApoA-IV suppressed lipopolysaccharide (LPS)-induced IKK and JNK phosphorylation in Raw264.7 macrophage cell culture assays. When the culture medium was supplemented to 3T3-L1 adipocytes they exhibited an increased sensitivity to insulin. ApoA-IV protects against obesity-associated metabolic inflammation mainly through suppression in M1 macrophages of eWAT, IL17-IKK and IL17-JNK activity.

Pharmacology Mechanism of Polygonum Bistorta in Treating Ulcerative Colitis Based on Network Pharmacology

Aim. Ulcerative colitis (UC) is a refractory gastrointestinal disease. The study aimed to expound the mechanism of Polygonum bistorta (PB) in treating UC by network pharmacology, molecular docking, and experiment verification. Methods. The compositions and targets of PB and UC-associated targets were obtained by searching the websites and the literature. The potential mechanism of PB in the treatment of UC was predicted by protein-protein interaction network construction, Gene Ontology (GO), and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway enrichment analysis. Molecule docking was performed by AutoDock. In vitro experiments explored the mechanism of quercetin (Que), the main active composition of PB, in treating UC. Results. Six compositions, 139 PB targets, and 934 UC-associated targets were obtained. 93 overlapping targets between PB and UC were identified, and 18 of them were the core targets. 467 biological processes, 10 cell components, and 30 molecular functions were obtained by GO analysis. 102 pathways were enriched through KEGG analysis. Among them, the IL-17 signaling pathway had high importance. The core targets FOS, JUN, IL-1β, CCL2, CXCL8, and MMP9 could dock with Que successfully. Act1, TRAF6, FOS, and JUN were identified by KEGG as the key proteins of the IL-17 signaling pathway. The expressions of the abovementioned proteins were increased in Caco-2 cells stimulated by Dextran sulfate sodium and decreased after being treated by Que. Conclusion. PB might treat UC by downregulating the IL-17 signaling pathway. It is worth doing further research on PB treating UC in vivo.

Rat and fish peripheral blood leukocytes respond distinctively to Anisakis pegreffii (Nematoda, Anisakidae) crude extract

Infective third-stage larvae (L3) of the marine nematode Anisakis pegreffii cause inflammation and clinical symptoms in humans, their accidental host, that subside and self-resolve in a couple of weeks after L3 die. To characterise the differences in an early immune response of a marine vs. terrestrial host, we stimulated peripheral blood leukocytes (PBLs) of fish (paratenic host) and rat (accidental, human-model host) with A. pegreffii crude extract and analysed PBL transcriptomes 1 and 12 h post-stimulation. Fish and rat PBLs differentially expressed 712 and 493 transcripts, respectively, between 1 and 12 h post-stimulation (false discovery rate, FDR <0.001, logFC >2). While there was a difference in the highest upregulated transcripts between two time-points, the same Gene Ontologies, biological processes (intracellular signal transduction, DNA-dependent transcription, and DNA-regulated regulation of transcription), and molecular functions (ATP and metal ion binding) were enriched in the two hosts, showing an incrementing dynamic between 1 and 12 h. This suggests that the two distinct hosts employ qualitatively different transcript cascades only to achieve the same effect, at least during an early innate immunity response. Activation of later immunity elements and/or a combination of other host's intrinsic conditions may contribute to the death of L3 in the terrestrial host.

Th17-Derived Cytokines Synergistically Enhance IL-17C Production by the Colonic Epithelium

Tightly regulated communication between the gastrointestinal epithelium and immune cells in the underlying lamina propria is critical for immune homeostasis and inflammation. IL-17C, produced by epithelial cells after exposure to inflammatory stimuli, facilitates cell-to-cell communication by promoting inflammatory responses in Th17 cells. In this study, we demonstrate that Th17-derived cytokines TNF-α, IL-17A, and IL-22 synergistically enhance IL-17C expression in both human-transformed colonic epithelial cell lines and primary non-inflammatory bowel disease colonic epithelial spheroids. This synergistic expression requires activation of the transcription factor NF-κB downstream of the TNF-α stimulus, evidenced by the reduction of IL-17C expression in the presence of an IκBα inhibitor. IL-17A and IL-22 enhance IL-17C expression through the activation of the transcription factor AP-1 in a p38 MAPK-dependent manner. Colonic spheroids derived from uninvolved epithelial of ulcerative colitis patients stimulated with TNF-α, IL-17A, and IL-22 show muted responses compared with non-inflammatory bowel disease spheroids, and inflamed spheroids yielded more IL-17C expression in the presence of TNF-α, and no response to IL-22 stimulation. Altogether, a role for IL-17C in activating Th17 cells combined with our findings of Th17-derived cytokine-driven synergy in the expression of IL-17C identifies a novel inflammatory amplification loop in the gastrointestinal tract between epithelial cells and Th17 cells.

The Role of Interleukin-17 in Juvenile Idiopathic Arthritis: From Pathogenesis to Treatment

Background and Objectives: Interleukin-17 (IL-17) is a cytokine family consisting of six members and five specific receptors. IL-17A was the first member to be identified in 1993. Since then, several studies have elucidated that IL-17 has predominantly pro-inflammatory activity and that its production is involved in both the defense against pathogens and the genesis of autoimmune processes. Materials and Methods: In this review, we provide an overview of the role of interleukin-17 in the pathogenesis of juvenile idiopathic arthritis (JIA) and its relationship with IL-23, the so-called IL-23-IL-17 axis, by reporting updated findings from the scientific literature. Results: Strong evidence supports the role of interleukin-17A in the pathogenesis of JIA after the deregulated production of this interleukin by both T helper 17 (Th17) cells and cells of innate immunity. The blocking of IL-17A was found to improve the course of JIA, leading to the approval of the use of the human anti-IL17A monoclonal antibody secukinumab in the treatment of the JIA subtypes juvenile psoriatic arthritis (JPsA) and enthesitis-related arthritis (ERA). Conclusions: IL-17A plays a central role in the pathogenesis of JIA. Blocking its production with specific biologic drugs enables the effective treatment of this disabling childhood rheumatic disease.

Recombinant multimeric dog allergen prevents airway hyperresponsiveness in a model of asthma marked by vigorous TH 2 and TH 17 cell responses

BACKGROUND

Allergy to dogs affects around 10% of the population in developed countries. Immune therapy of allergic patients with dog allergen extracts has shown limited therapeutic benefit.

METHODS

We established a mouse model of dog allergy by repeatedly administering dog dander and epithelium extracts via the intranasal route. We also assessed the efficacy of a recombinant multimeric protein containing Can f 1, f 2, f 4 and f 6 in preventing inflammatory responses to dog extracts.

RESULTS

Repeated inhalation of dog extracts induced infiltration of the airways by T_H 2 cells, eosinophils and goblet cells, reminiscent of the house dust mite (HDM) model of asthma. Dog extracts also induced robust airway hyperresponsiveness and promoted T_H 17 cell responses, which was associated with a high neutrophilic infiltration of the airways. scRNA-Seq analysis of T helper cells in the airways pinpointed a unique gene signature for T_H 17 cells. Analysis of T-cell receptors depicted a high frequency of clones that were shared between T_H 17, T_H 2 and suppressive Treg cells, indicative of a common differentiation trajectory for these subsets. Importantly, sublingual administration of multimeric Can f 1-2-4-6 protein prior to sensitization reduced airway hyperresponsiveness and type 2-mediated inflammation in this model.

CONCLUSION

Dog allergen extracts induce robust T_H 2 and T_H 17 cell-mediated responses in mice. Recombinant Can f 1-2-4-6 can induce tolerance to complex dog allergen extracts.

Cytokines and chemokines: The vital role they play in herpes simplex virus mucosal immunology

Herpes simplex viruses (HSV) types 1 and 2 are ubiquitous infections in humans. They cause orofacial and genital herpes with occasional severe complications. HSV2 also predisposes individuals to infection with HIV. There is currently no vaccine or immunotherapy for these diseases. Understanding the immunopathogenesis of HSV infections is essential to progress towards these goals. Both HSV viruses result in initial infections in two major sites - in the skin or mucosa, either after initial infection or recurrence, and in the dorsal root or trigeminal ganglia where the viruses establish latency. HSV1 can also cause recurrent infection in the eye. At all of these sites immune cells respond to control infection. T cells and resident dendritic cells (DCs) in the skin/mucosa and around reactivating neurones in the ganglia, as well as keratinocytes in the skin and mucosa, are major sources of cytokines and chemokines. Cytokines such as the Type I and II interferons synergise in their local antiviral effects. Chemokines such as CCL2, 3 and 4 are found in lesion vesicle fluid, but their exact role in determining the interactions between epidermal and dermal DCs and with resident memory and infiltrating CD4 and CD8 T cells in the skin/mucosa is unclear. Even less is known about these mechanisms in the ganglia. Here we review the data on known sources and actions of these cytokines and chemokines at cellular and tissue level and indicate their potential for preventative and therapeutic interventions.

Interleukin-17 Family Cytokines in Metabolic Disorders and Cancer

Interleukin-17 (IL-17) family cytokines are potent drivers of inflammatory responses. Although IL-17 was originally identified as a cytokine that induces protective effects against bacterial and fungal infections, IL-17 can also promote chronic inflammation in a number of autoimmune diseases. Research in the last decade has also elucidated critical roles of IL-17 during cancer development and treatment. Intriguingly, IL-17 seems to play a role in the risk of cancers that are associated with metabolic disorders. In this review, we summarize our current knowledge on the biochemical basis of IL-17 signaling, IL-17′s involvement in cancers and metabolic disorders, and postulate how IL-17 family cytokines may serve as a bridge between these two types of diseases.

Generalized pustular psoriasis is a disease distinct from psoriasis vulgaris: evidence and expert opinion

INTRODUCTION

Generalized pustular psoriasis (GPP) is a rare, severe, clinically heterogeneous disease characterized by flares of widespread, non-infectious, macroscopically visible pustules that occur with or without systemic inflammation, and are associated with significant morbidity and mortality. Historically, GPP has been classified as a variant of psoriasis vulgaris (PV, or plaque psoriasis); however, accumulating evidence indicates that these are distinct conditions, requiring different treatment approaches.

AREAS COVERED

In this perspectives article we review evidence that supports the classification of GPP as distinct from PV.

EXPERT OPINION

The histopathologic and clinical appearance of GPP is distinct from that of PV and fundamental differences exist between the two conditions in terms of genetic causes and expression-related mechanisms of disease development. GPP results from dysregulation of the innate immune system, with disruption of the interleukin (IL)-36 inflammatory pathway, induction of inflammatory keratinocyte responses, and recruitment of neutrophils. PV is driven by the adaptive immune system, with a key role played by IL-17. Considering GPP as a separate disease will enable greater focus on its specific pathogenesis and the needs of patients. Many treatments for PV have insufficient efficacy in GPP and a therapeutic approach developed specifically for GPP might lead to better patient outcomes.

Role of IL-17 family cytokines in the progression of IPF from inflammation to fibrosis

Idiopathic pulmonary fibrosis (IPF) is a fatal chronic interstitial lung disease with no established treatment and is characterized by progressive scarring of the lung tissue and an irreversible decline in lung function. Chronic inflammation has been demonstrated to be the pathological basis of fibrosis. Emerging studies have revealed that most interleukin-17 (IL-17) isoforms are essential for the mediation of acute and chronic inflammation via innate and adaptive immunity. Overexpression or aberrant expression of IL-17 cytokines contributes to various pathological outcomes, including the initiation and exacerbation of IPF. Here, we aim to provide an overview of IL-17 family members in the pathogenesis of IPF.

Eczematous drug eruption in patients with psoriasis under anti-interleukin-17A: does interleukin-22 play a key role?

BACKGROUND

Eczematous drug eruption (EDE) is a spongiotic skin reaction in response to systemic medications. To date, EDE has been described in patients treated with anti-interleukin (IL)-17A monoclonal antibodies with a prevalence of 2.2%-12.1%.

AIM

To describe the clinical and histological features and the skin cytokine milieu in patients with EDE induced by anti-IL-17A biologics.

METHODS

This was a prospective study, enrolling patients with psoriasis who developed EDE during treatment with two anti-IL-17 biologics, ixekizumab and secukinumab, from June 2019 to April 2021. Skin biopsies were taken from all patients: a 5-mm lesional biopsy (LB) and a 3-mm nonlesional biopsy (NLB). The LB sample was split into two parts, one for histological examination and the other for cytokine profile evaluation.

RESULTS

During the study period, treatment with an anti-IL-17A drug was given to 289 patients of whom 8 (2.8%) developed EDE during the treatment. Histopathological evaluation suggested a diagnosis of spongiotic dermatitis in all eight patients. Cytokine gene expression showed a predominance of T helper (Th)2/Th22 cytokines in EDE lesions with a large increase in IL-4, IL-22 and S100A7 levels in both LB and NLB samples compared with healthy skin. IL-4, IL-22 and S100A7 were significantly higher in LB compared with NLB samples. IL-26 levels were also significantly increased in both LB and NLB compared with healthy skin, whereas low levels of IL-23A were found in both LB and NLB.

CONCLUSION

Eczematous drug eruption skin lesions have mainly Th2/Th22 features, with IL-22 playing a major role in their pathogenesis. EDE seems to be the result of an imbalance towards a Th2/Th22 response, secondary to the blockade of IL-17A activity.

IL-17RA blockade by brodalumab decreases inflammatory pathways in hidradenitis suppurativa skin and serum

BACKGROUND

Hidradenitis suppurativa (HS) is an inflammatory skin disease with dysregulation of the IL-17 axis. Recently we reported clinical benefit of brodalumab, a human anti-IL-17 receptor A (IL-17RA) monoclonal antibody, in moderate-to-severe HS.

OBJECTIVES

To characterize the molecular response to brodalumab in HS skin and serum, and to identify biomarkers of treatment response.

METHODS

Ten participants that received 210 mg/1.5mL brodalumab subcutaneously at week 0, 1, 2, 4 and every 2 weeks after were included in this molecular profiling study (NCT03960268). RNA-sequencing and immunohistochemistry of nonlesional, perilesional and lesional HS skin biopsies, and Olink high throughput proteomics of serum at baseline, week 4 and week 12 were assessed.

RESULTS

At week 12, brodalumab led to a decrease of overall inflammation, and improvement of psoriasis-, keratinocyte- and neutrophil-related pathways. Despite perilesional and lesional skin having no differentially expressed genes at baseline, treatment response was best assessed in perilesional skin. In serum, brodalumab treatment decreased pathways involved in neutrophil inflammation. Patients with higher baseline expression of neutrophil-associated Lipocalin-2 (LCN2) in the skin and IL-17A in the serum demonstrated greater decreases of HS-related inflammatory cytokines as measured in skin biopsies at week 12.

CONCLUSIONS

IL-17RA inhibition by brodalumab impacts several pathogenic inflammatory axes in HS. Perilesional skin provides a valid and robust assessment of treatment response. Expression of LCN2 in skin and IL-17A in serum may be used as biomarkers to stratify patients that may have a superior molecular response to brodalumab =.

Orchestrated Cytokines Mediated by Biologics in Psoriasis and Its Mechanisms of Action

Psoriasis is an autoimmune disease mediated by disturbed T cells and other immune cells, and is defined by deep-red, well-demarcated skin lesions. Due to its varied etiologies and indefinite standard pathogenesis, it is challenging to consider the right treatment exclusively for each psoriasis patient; thus, researchers yearn to seek even more precise treatments other than topical treatment and systemic therapy. Using biologics to target specific immune components, such as upregulated cytokines secreted by activated immune cells, is the most advanced therapy for psoriasis to date. By inhibiting the appropriate pro-inflammatory cytokines, cellular signaling can be altered and, thus, can inhibit further downstream inflammatory pathways. Herein, the roles of cytokines with their mechanisms of action in progressing psoriasis and how the usage of biologics alleviates cellular inflammation are discussed. In addition, other potential pro-inflammatory cytokines, with their mechanism of action, are presented herein. The authors hope that this gathered information may benefit future research in expanding the discovery of targeted psoriasis therapy.

Interleukin-17 Receptor E and C-C Motif Chemokine Receptor 10 Identify Heterogeneous T Helper 17 Subsets in a Mouse Dry Eye Disease Model

Dry eye disease (DED) features the inflammatory response of the ocular surface. Pro-inflammatory T helper 17 (Th17) cells are important for the pathogenesis of DED. In the present study a mouse DED model was used to discover two Th17 subsets in draining lymph nodes and conjunctivae based on the expression of IL-17 receptor E (IL-17RE) and CCR10: IL-17RE^lowCCR10^- Th17 and IL-17RE^highCCR10⁺ Th17. IL-17RE^highCCR10⁺ Th17 expressed more retinoic acid-related orphan receptor gamma t but fewer T-box-expressed-in-T-cells than IL-17RE^lowCCR10^- Th17. In addition, the former expressed higher IL-17A, IL-21, and IL-22 but fewer IFN-γ than the latter. Further analysis showed that IL-17RE^highCCR10⁺ Th17 did not express IFN-γ in vivo, whereas IL-17RE^lowCCR10^- Th17 contained IFN-γ-expressing Th17/Th1 cells. Moreover, IL-17RE^highCCR10⁺ Th17 possessed more phosphorylated p38 mitogen-activated protein kinase (MAPK) and Jnk than IL-17RE^lowCCR10^- Th17, suggesting higher activation of MAPK signaling in IL-17RE^highCCR10⁺ Th17. In vitro treatment with IL-17C effectively maintained IL-17A expression in Th17 cells through p38 MAPK rather than Jnk MAPK. Furthermore, the adoptive transfer of the two Th17 subpopulations indicated their equivalent pathogenicity in DED. Interestingly, IL-17RE^highCCR10⁺ Th17 cells were able to phenotypically polarize to IL-17RE^lowCCR10^- Th17 cells in vivo. In conclusion, the current study revealed novel Th17 subsets with differential phenotypes, functions, and signaling status in DED, thus deepening the understanding of Th17 pathogenicity, and exhibited Th17 heterogeneity in DED.

Interleukin 17 receptor E identifies heterogeneous T helper 17 cells in peritoneal fluid of moderate and severe endometriosis patients

Endometriosis is a chronic inflammatory disorder resulting in pelvic pain and infertility. The role of T helper 17 (Th17) cells in endometriosis remains elusive. In this study, through detecting CXCR3, CCR4, CCR10, CCR6, interleukin-17 Receptor E (IL-17RE), and CD27, RORγt-and-IL-17A-expressing Th17 cells were distinguished and sorted from peritoneal fluid (PF) of patients with stage III and IV endometriosis. Furthermore, we found that IL-17RE and CD27 were the labels of heterogeneous PF Th17 subsets, i.e. IL-17RE-CD27- subset, IL-17RE+CD27- subset, and IL-17RE+CD27+ subset. The former two subsets expressed higher IL-17A, GM-CSF, and IL-22 and were more proliferative than the latter subset. RNA-Seq analysis on IL-17RE+ Th17 subset and IL-17RE- Th17 subset revealed up-regulation of genes involved in oxidative phosphorylation and electron transport chain in IL-17RE+ Th17 subset relative to IL-17RE- Th17 subset. Consistently, the IL-17RE+ Th17 subset produced more adenosine triphosphate (ATP) and reactive oxygen species (ROS) than IL-17RE- Th17 subset. In conclusion, this study provides a novel method to detect and isolate live PF Th17 cells from endometriosis patients and unveils the functional and metabolic heterogeneity of PF Th17 subsets. Therefore, it sheds light on the elucidation of molecular mechanisms that modulate the function of pathological Th17 cells in endometriosis.

T cell transgressions: Tales of T cell form and function in diverse disease states

Insights into T cell form, function, and dysfunction are rapidly evolving. T cells have remarkably varied effector functions including protecting the host from infection, activating cells of the innate immune system, releasing cytokines and chemokines, and heavily contributing to immunological memory. Under healthy conditions, T cells orchestrate a finely tuned attack on invading pathogens while minimizing damage to the host. The dark side of T cells is that they also exhibit autoreactivity and inflict harm to host cells, creating autoimmunity. The mechanisms of T cell autoreactivity are complex and dynamic. Emerging research is elucidating the mechanisms leading T cells to become autoreactive and how such responses cause or contribute to diverse disease states, both peripherally and within the central nervous system. This review provides foundational information on T cell development, differentiation, and functions. Key T cell subtypes, cytokines that create their effector roles, and sex differences are highlighted. Pathological T cell contributions to diverse peripheral and central disease states, arising from errors in reactivity, are highlighted, with a focus on multiple sclerosis, rheumatoid arthritis, osteoarthritis, neuropathic pain, and type 1 diabetes.

Identification of heterogeneous subsets of aortic interleukin-17A-expressing CD4+ T cells in atherosclerotic mice

Objectives: T helper 17 (Th17) cells are involved in the inflammatory response of atherosclerosis. However, their heterogeneity in the atherosclerotic aorta remains elusive. This study was designed to identify aortic Th17 subsets. Methods: The surface markers and transcription factors of aortic interleukin-17A (IL-17A)-expressing T cells were determined by flow cytometry in an ApoE-deficient mouse atherosclerotic model. Viable aortic IL-17A-expressing T cell subsets were isolated by flow cytometry on the basis of surface markers, followed by characterizing their transcription factors by either flow cytometry or real-time RT-PCR. The effect of aortic IL-17A-expressing T cell subsets on aortic endothelial cells was determined in vitro. Results: C-X-C Motif Chemokine Receptor 3 (CXCR3), interleukin-17 receptor E (IL-17RE), CD200, and C-C Motif Chemokine Receptor 4 (CCR4) marked three subsets of aortic IL-17A-expressing T cells: CXCR3⁺IL-17RE^lowCD200⁺CCR4^- T cells expressing T-box protein expressed in T cells (T-bet) and interferon-gamma (IFN-γ), CXCR3⁺IL-17RE^lowCD200⁺CCR4⁺ T cells expressing T-bet but fewer IFN-γ, and CXCR3⁻IL-17RE^highCD200⁺CCR4⁺ T cells expressing very low T-bet and no IFN-γ. Based on these markers, viable aortic Th17 cells, Th17.1 cells, and transitional Th17.1 cells were identified. Both Th17.1 cells and transitional Th17.1 cells were more proliferative than Th17 cells. Compared with Th17 cells, Th17.1 cells plus transitional Th17.1 cells induced higher expression of C-X-C motif chemokine ligand 1 (CXCL1), C-C motif chemokine ligand 2 (CCL2), C-X-C motif chemokine 5 (CXCL5), and granulocyte-macrophage colony-stimulating factor (GM-CSF) in aortic endothelial cells. Conclusion: IL-17A-expressing CD4⁺ T cells were heterogeneous in atherosclerotic aortas.

The biological basis of disease recurrence in psoriasis: a historical perspective and current models

A key challenge in psoriasis therapy is the tendency for lesions to recur in previously affected anatomical locations after treatment discontinuation following lesion resolution. Available evidence supports the concept of a localized immunological ‘memory’ that persists in resolved skin after complete disappearance of visible inflammation, as well as the role of a specific subpopulation of T cells characterized by the dermotropic CCR4⁺ phenotype and forming a local memory. Increasing knowledge of the interleukin (IL)‐23/T helper 17 (Th17) cell pathway in psoriasis immunopathology is pointing away from the historical classification of psoriasis as primarily a Th1‐type disease. Research undertaken from the 1990s to the mid‐2000s provided evidence for the existence of a large population of CD8⁺ and CD4⁺ tissue‐resident memory T cells in resolved skin, which can initiate and perpetuate immune responses of psoriasis in the absence of T‐cell recruitment from the blood. Dendritic cells (DCs) are antigen‐presenting cells that contribute to psoriasis pathology via the secretion of IL‐23, the upstream regulator of Th17 cells, while plasmacytoid DCs are involved via IL‐36 signalling and type I interferon activation. Overall, the evidence discussed in this review indicates that IL‐23‐driven/IL‐17‐producing T cells play a critical role in psoriasis pathology and recurrence, making these cytokines logical therapeutic targets. The review also explains the clinical efficacy of IL‐17 and IL‐23 receptor blockers in the treatment of psoriasis.

IL-17 Receptor C Signaling Controls CD4+ TH17 Immune Responses and Tissue Injury in Immune-Mediated Kidney Diseases

BACKGROUND

IL-17A-producing CD4⁺ T helper (T_H17) cells play a critical role in autoimmune and chronic inflammatory diseases, such as crescentic GN. The proinflammatory effects of IL-17 are mediated by the activation of the IL-17RA/IL-17RC complex. Although the expression of these receptors on epithelial and endothelial cells is well characterized, the IL-17 receptor expression pattern and function on hematopoietic cells, e.g., CD4⁺ T cell subsets, remains to be elucidated.

METHODS

Crescentic GN (nephrotoxic nephritis) was induced in IL-17A, IFNγ, and Foxp3 triple-reporter mice for sorting of renal CD4⁺ T cell subsets and subsequent single-cell RNA sequencing. Moreover, we generated T_H17 cell-specific IL-17RA and IL-17RC gene-deficient mice and studied the functional role of IL-17 signaling in T_H17 cells in crescentic GN, imiquimod-induced psoriasis, and in the CD4⁺CD45RB^high T cell transfer colitis model.

RESULTS

We identified a specific expression of the IL-17 receptor A/C complex on CD4⁺ T_H17 cells. Single-cell RNA sequencing of T_H17 cells revealed the activation of the IL-17 receptor signaling pathway in experimental crescentic GN. Disruption of the IL-17RC signaling pathway in CD4⁺ T cells and, most importantly, specifically in CD4⁺ T_H17 cells, potentiates the IL-17 cytokine response and results in an accelerated course of experimental crescentic GN. Comparable results were observed in experimental models of psoriasis and colitis.

CONCLUSIONS

Our findings indicate that IL-17 receptor C signaling has a previously unrecognized function in the regulation of CD4⁺ T_H17 cells and in the control of organ-specific autoimmunity and might provide new insights into the development of more efficient anti-T_H17 treatment strategies.

Interleukin-17 family members in health and disease

The interleukin-17 (IL-17) family consists of six family members (IL-17A-IL-17F) and all the corresponding receptors have been identified recently. This family is mainly involved in the host defense mechanisms against bacteria, fungi and helminth infection by inducing cytokines and chemokines, recruiting neutrophils, inducing anti-microbial proteins and modifying T-helper cell differentiation. IL-17A and some other family cytokines are also involved in the development of psoriasis, psoriatic arthritis and ankylosing spondylitis by inducing inflammatory cytokines and chemokines, and antibodies against IL-17A as well as the receptor IL-17RA are being successfully used for the treatment of these diseases. Involvement in the development of inflammatory bowel disease, multiple sclerosis, rheumatoid arthritis and tumors has also been suggested in animal disease models. In this review, we will briefly review the mechanisms by which IL-17 cytokines are involved in the development of these diseases and discuss possible treatment of inflammatory diseases by targeting IL-17 family members.

RNA-sequencing identifies differentially expressed genes in T helper 17 cells in peritoneal fluid of patients with endometriosis

Innate and adaptive immune factors play significant roles in the pathophysiology of endometriosis. T helper 17 (Th17) cells, a pro-inflammatory T cell subset, were considered to contribute to the progression of endometriosis lesions. However, the regulatory mechanisms of Th17 cells in endometriosis remain unidentified, partially due to the difficulty in recovering live Th17 cells from endometriosis patients. In this study, by flow cytometry analysis of a set of chemokine receptors including CXCR3, CCR4, CCR10, and CCR6, live RORγt-and-IL-17A-expressing Th17 cells were enriched from peritoneal fluid (PF) of patients with different stages of endometriosis for the first time, RNA-sequencing (RNA-Seq) of these PF Th17 cells revealed significantly up-regulated genes and down-regulated genes in stage I-II and stage III-IV endometriosis, compared with their counterparts in normal PF. In conclusion, this study provides a novel method to isolate live Th17 cells from endometriosis patients, unveils an array of differentially expressed genes in endometriosis Th17 cells, and offers valuable gene expression profile information for endometriosis clinical research.