IL-23 promotes maintenance but not commitment to the Th17 lineage

Selection and evaluation of single domain antibody against p19 subunit of IL-23 by phage display for potential use as an autoinflammatory therapeutic

IL-23 is a double-subunit cytokine that plays an important role in shaping the immune response. IL-23 was found to be associated with several autoinflammatory diseases by generating sustained inflammatory loops that lead to tissue damage. Antibody neutralization of IL-23 was proven to be effective in ameliorating associated diseases. However, antibodies as large proteins have limited tissue penetration and tend to elicit anti-drug antibodies. Additionally, anti-IL-23 antibodies target only one subunit of IL-23 leaving the other one unneutralized. Here, we attempted to isolate a recycling single domain antibody by phage display. One of IL-23 subunits, p19, was expressed in E. coli fused to Gamillus protein to stabilize the α-helix-only p19. To remove Gamillus binders, two biopanning methods were investigated, first, preselection with Gamillus and second, challenge with IL-23 then on the subsequent round challenge with p19-Gam. The isolation of calcium-dependent and pH-dependent recycling binders was performed with EDTA and citrate buffers respectively. Both methods of panning failed to isolate high-affinity and specific p19 recycling binders, while from the second panning method, a high affinity and specific p19 standard binder, namely H11, was successfully isolated. H11 significantly inhibited the gene expression of IL-17 and IL-22 in IL-23-challenged PBMCs indicating H11 specificity and neutralizing ability for IL-23. The new binder due to its small size can overcome antibodies limitations, also, it can be further engineered in the future for antigen clearance such as fusing it to cell penetrating peptides, granting H11 the ability to clear excess IL-23 and enhancing its potential therapeutic effect.

Correlation of Professional Antigen-Presenting Tbet+CD11c+ B Cells With Bone Destruction in Untreated Rheumatoid Arthritis

OBJECTIVE

Subsets of CD21-/low memory B cells (MBCs), including double-negative (DN, CD27-IgD-) and Tbet+CD11c+ cells, are expanded in chronic inflammatory diseases. In rheumatoid arthritis (RA), CD21-/low MBCs correlate with joint destruction. However, whether this is due to the Tbet+CD11c+ subset, its function and pathogenic contribution to RA are unknown. This study aims to investigate the association between CD21-/lowTbet+CD11c+ MBCs and joint destruction as well as other clinical parameters and to elucidate their functional properties in patients with untreated RA (uRA).

METHODS

Clinical observations were combined with flow cytometry (n = 36) and single-cell RNA sequencing (scRNA-seq) and V(D)J sequencing (n = 4) of peripheral blood (PB) MBCs from patients with uRA. The transcriptome of circulating Tbet+CD11c+ MBCs was compared with scRNA-seq data of synovial B cells. In vitro coculture of Tbet+CD11c+ B cells with T cells was used to assess costimulatory capacity.

RESULTS

CD21-/lowTbet+CD11c+ MBCs in PB correlated with bone destruction but no other clinical parameters analyzed. The Tbet+CD11c+ MBCs have undergone clonal expansion and express somatically mutated V genes. Gene expression analysis of these cells identified a unique signature of more than 150 up-regulated genes associated with antigen presentation functions, including B cell receptor activation and clathrin-mediated antigen internalization; regulation of actin filaments, endosomes, and lysosomes; antigen processing, loading, presentation, and costimulation; a transcriptome mirrored in their synovial tissue counterparts. In vitro, Tbet+CD11c+ B cells induced retinoic acid receptor-related orphan nuclear receptor γT expression in CD4+ T cells, thereby polarizing to Th17 cells, a T cell subset critical for osteoclastogenesis and associated with bone destruction.

CONCLUSION

This study suggests that Tbet+CD11c+ MBCs contribute to the pathogenesis of RA by promoting bone destruction through antigen presentation, T cell activation, and Th17 polarization.

Single-cell mass cytometry in immunological skin diseases

Immune-related skin diseases represent a collective of dermatological disorders intricately linked to dysfunctional immune system processes. These conditions are primarily characterized by an immoderate activation of the immune system or deviant immune responses, involving diverse immune components including immune cells, antibodies, and inflammatory mediators. However, the precise molecular dysregulation underlying numerous individual cases of these diseases and unique subsets respond under disease conditions remains elusive. Comprehending the mechanisms and determinants governing the homeostasis and functionality of diseases could offer potential therapeutic opportunities for intervention. Mass cytometry enables precise and high-throughput quantitative measurement of proteins within individual cells by utilizing antibodies labeled with rare heavy metal isotopes. Imaging mass cytometry employs mass spectrometry to obtain spatial information on cell-to-cell interactions within tissue sections, simultaneously utilizing more than 40 markers. The application of single-cell mass cytometry presents a unique opportunity to conduct highly multiplexed analysis at the single-cell level, thereby revolutionizing our understanding of cell population heterogeneity and hierarchy, cellular states, multiplexed signaling pathways, proteolysis products, and mRNA transcripts specifically in the context of many autoimmune diseases. This information holds the potential to offer novel approaches for the diagnosis, prognostic assessment, and monitoring responses to treatment, thereby enriching our strategies in managing the respective conditions. This review summarizes the present-day utilization of single-cell mass cytometry in studying immune-related skin diseases, highlighting its advantages and limitations. This technique will become increasingly prevalent in conducting extensive investigations into these disorders, ultimately yielding significant contributions to their accurate diagnosis and efficacious therapeutic interventions.

Safety of tildrakizumab: a disproportionality analysis based on the FDA adverse event reporting system (FAERS) database from 2018-2023

Background: Tildrakizumab, the IL-23 inhibitor, is used to treat plaque psoriasis and psoriatic arthritis. Many studies have reported adverse drug reactions (ADRs) associated with Tildrakizumab. Objective: The aim of this study was to describe ADRs associated with Tildrakizumab monotherapy by mining data from the U.S. Food and Drug Administration Adverse Event Reporting System (FAERS). Methods: The signals of Tildrakizumab-associated ADRs were quantified using disproportionality analyses such as the reporting odds ratio (ROR), the proportional reporting ratio (PRR), the Bayesian confidence propagation neural network (BCPNN), and the multiitem gamma Poisson shrinker (MGPS) algorithms. Results: A total of 10,530,937 reports of ADRs were collected from the FAERS database, of which 1,177 reports were identified with tildrakizumab as the "primary suspect (PS)". Tildrakizumab-induced ADRs occurred against 27 system organ classes (SOCs). A total of 32 significant disproportionality Preferred Terms (PTs) conformed to the algorithms. Unexpected significant ADRs such as coronavirus infection, herpes simplex, diverticulitis, atrial fibrillation and aortic valve incompetence were also possible. The median time to onset of Tildrakizumab-associated ADRs was 194 days (interquartile range [IQR] 84-329 days), with the majority occurring, within the first 1 and 3 months after initiation of Tildrakizumab. Conclusion: This study identified a potential signal for new ADRs with Tildrakizumab, which might provide important support for clinical monitoring and risk prediction.

Altered gene expression of miR-155 in peripheral blood mononuclear cells of Multiple sclerosis patients: Correlation with TH17 frequency, inflammatory cytokine profile and autoimmunity

In the chronic, organ-specific autoimmune disorder known as multiple sclerosis (MS), the myelin sheath is attacked by immune cells, leading to damage to the central nervous system (CNS). It has been discovered that miRNAs are important in the etiology of MS, since deregulation of miRNAs can lead to defects in immune tolerance. In this study, we sought to investigate the involvement of miR-155 in MS disorder through examination of its altered expression in peripheral blood mononuclear cells (PBMCs) of patients with MS in compare with healthy controls. Furthermore, we investigated the frequency of T helper 17 cells (Th17) in MS patients and analyzed not only the expression of inflammatory cytokines including IL-6, IL-17 and IL-21 in patients' PBMCs, but also their secreted levels in serum of patients suffering from MS. Subsequently, we assessed the correlation between miR-155 expression with Th17 frequency and levels of released cytokines in serum. Upregulated expression of miR-155 was detected in PBMCs of MS patients and the positive correlation between its expression with increased frequency of Th17 cells and their related inflammatory cytokine profile augmented secretion in serum were identified. In conclusion, our study revealed the significant association between Th17 frequency, increased level of cytokines related to Th17 differentiation and function with miR-155 augmented expression in PBMCs. So, our findings suggested that miR-155 and especially its expression in immune cells including effector T cells can be the target of future therapeutic strategies for the management and prevention of MS progression, however, further research is requisite before this approach can be utilized in clinical practice.

Differential requirement for IL-2 and IL-23 in the differentiation and effector functions of Th17/ILC3-like cells in a human T cell line

A well-documented Achilles heel of current cancer immunotherapy approaches is T cell exhaustion within solid tumor tissues. The proinflammatory cytokine interleukin (IL)-23 has been utilized to augment chimeric antigen receptor (CAR) T cell survival and tumor immunity. However, in-depth interrogation of molecular events downstream of IL-23/IL-23 receptor signaling is hampered by a paucity of suitable cell models. The current study investigates the differential contribution of IL-2 and IL-23 to the maintenance and differentiation of the IL-23 responsive Kit225 T-cell line. We observed that IL-23 enhanced cellular fitness and survival but was insufficient to drive proliferation. IL-23 rapidly induced phosphorylation of STAT1, STAT3, and STAT4, and messenger RNA expression of IL17A, the archetypal effector cytokine of T helper 17 (Th17) cells, but not their lineage markers RORC and NCR1. These observations suggest that IL-23 endowed Th17/ILC3-like effector function but did not promote their differentiation. In contrast, spontaneous differentiation of Kit225 cells toward a Th17/ILC3-like phenotype was induced by prolonged IL-2 withdrawal. This was marked by strongly elevated basal IL17A and IL17F expression and the secretion of IL-17. Together, our data present Kit225 cells as a valuable model for studying the interplay between cytokines and their contribution to T cell survival, proliferation, and differentiation.

Clinical pharmacokinetics and pharmacodynamics of oral systemic nonbiologic therapies for psoriasis patients

INTRODUCTION

Psoriasis is a chronic inflammatory immune condition. Treatments for psoriasis vary with disease severity, ranging from topicals to systemic biologic agents. The pharmacokinetic (PK) and pharmacodynamic (PD) properties of these therapies establish drug efficacy, toxicity, and optimal dosing to ensure therapeutic drug levels are sustained and adverse effects are minimized.

AREAS COVERED

A literature search was performed on PubMed, Google Scholar, and Ovid MEDLINE for PK and PD, efficacy, and safety data regarding oral systemic nonbiologic therapies utilized for moderate-to-severe plaque psoriasis. The findings were organized into sections for each drug: oral acitretin, methotrexate, cyclosporine, apremilast, tofacitinib, and deucravacitinib.

EXPERT OPINION

Some psoriasis patients may not respond to initial therapy. Ongoing research is evaluating genetic polymorphisms that may predict an improved response to specific medications. However, financial and insurance barriers, as well as limited genetic polymorphisms correlated with treatment response, may restrict the implementation of genetic testing necessary to personalize treatments. How well psoriasis patients adhere to treatment may contribute greatly to variation in response. Therapeutic drug monitoring may help patients adhere to treatment, improve clinical response, and sustain disease control.

Gene polymorphisms of an interleukin-23 receptor associated with susceptibility to rheumatoid arthritis in the Western Chinese Han population

Rheumatoid arthritis (RA) is a chronic inflammatory disease which is closely related to genetic background. Single-nucleotide polymorphisms (SNPs) have been found to play an important role in the development of RA. This study intends to investigate the links between gene polymorphisms in the interleukin-23 receptor (IL23R) and interleukin 17A (IL17A) and susceptibility to RA in the Western Chinese Han population. Four SNPs (rs6693831 T > C, rs1884444 G > T, and rs7517847 T > G in IL23R gene, and rs2275913 G > A in IL17A gene) were genotyped in 246 RA patients and 362 healthy controls by high resolution melting analysis. The comparative analyses among genotype distributions, clinical indicators, and IL-17A and IL-23R levels in RA patients were also performed. The study revealed that the SNP rs6693831 and rs1884444 of IL23R had a significant association with RA susceptibility. The frequencies of rs6693831 genotype CC and allele C were significantly higher in the RA group and associated with higher RA risk compared with genotype TT and allele T (OR = 7.797, 95% confidence interval [CI] = 4.072-14.932 and OR = 5.984, 95%CI = 3.190-11.224, respectively). The TT genotype of rs1884444 appeared to decrease the RA risk compared with the GG genotype (OR = .251, 95%CI = .118-.536). The genotype CC and allele C of rs6693831 and the genotype GG and allele G of rs1884444 may be risk factors for RA. IL23R gene polymorphisms may be involved in the risk of RA susceptibility in the Western Chinese Han population.

ZEB1 shapes AML immunological niches, suppressing CD8 T cell activity while fostering Th17 cell expansion

Acute myeloid leukemia (AML) progression is influenced by immune suppression induced by leukemia cells. ZEB1, a critical transcription factor in epithelial-to-mesenchymal transition, demonstrates immune regulatory functions in AML. Silencing ZEB1 in leukemic cells reduces engraftment and extramedullary disease in immune-competent mice, activating CD8 T lymphocytes and limiting Th17 cell expansion. ZEB1 in AML cells directly promotes Th17 cell development that, in turn, creates a self-sustaining loop and a pro-invasive phenotype, favoring transforming growth factor β (TGF-β), interleukin-23 (IL-23), and SOCS2 gene transcription. In bone marrow biopsies from AML patients, immunohistochemistry shows a direct correlation between ZEB1 and Th17. Also, the analysis of ZEB1 expression in larger datasets identifies two distinct AML groups, ZEB1high and ZEB1low, each with specific immunological and molecular traits. ZEB1high patients exhibit increased IL-17, SOCS2, and TGF-β pathways and a negative association with overall survival. This unveils ZEB1's dual role in AML, entwining pro-tumoral and immune regulatory capacities in AML blasts.

HMGB1 regulates Th17 cell differentiation and function in patients with psoriasis

BACKGROUND

Psoriasis is an immune-mediated chronic inflammatory skin disease, in which T helper 17 (Th17) cells and its effective cytokine interleukin (IL)-17A play a pivotal pathogenic role. High mobility group box 1 (HMGB1) is an important proinflammatory cytokine, which has been confirmed to be highly expressed in the peripheral circulation and epidermis tissues of psoriasis patients. The regulatory effect of HMGB1 on IL-17A expression and function has been reported in some inflammatory and autoimmune diseases by the HMGB1-Toll-like receptor 4 (TLR4)-interleukin (IL)-23-IL-17A pathway. While, in the pathological environment of psoriasis, whether HMGB1 can exert the regulatory effect on IL-17A is not clear.

OBJECTIVE

We aimed to evaluate the role of HMGB1-TLR4-IL-23-IL-17A pathway in the pathogenesis of psoriasis and explore the possible regulatory mechanism of HMGB1 on Th17 cell differentiation.

METHODS

Serum levels of HMGB1, TLR4, IL-23, and IL-17A were quantified in 50 patients with moderate-to-severe plaque psoriasis and 30 healthy controls. Peripheral blood mononuclear cells  were acquired from 10 severe psoriasis patients and administrated by different concentrations of recombinant-HMGB1 (rHMGB1) to detect the Th17 cell percentage, mRNA and protein levels of TLR4, IL-23, IL-17A and retinoid-related orphan receptor γt (RORγt).

RESULTS

The serum levels of HMGB1, TLR4, IL-23, and IL-17A in psoriasis patients were significantly higher than healthy controls, especially in severe patients, and positively correlated with the severity index. There were also positive correlations between every two detected indicators of HMGB1, TLR4, IL-23, and IL-17A. In vitro study, rHMGB1 can promote the elevated expression of Th17 cell percentage as well as TLR4, IL-23, IL-17A, and RORγt in a dose-dependent manner.

CONCLUSION

HMGB1 can contribute to the pathogenesis of psoriasis by regulating Th17 cell differentiation through HMGB1-TLR4-IL-23-RORγt pathway, then promotes IL-17A production and aggravates inflammation process. Targeting HMGB1 may be a possible potential candidate for the immunotherapy of psoriasis.

The IL-17 pathway as a target in giant cell arteritis

The network of IL-17 cytokines is considered a key component of autoimmune and inflammatory processes. Blocking IL-17 showed great success in psoriasis as well as psoriatic arthritis, and in patients with axial spondyloarthritis. Secukinumab is one of the approved IL-17A inhibitors for these diseases and is now routinely used. In giant cell arteritis, a large vessel vasculitis, there is accumulating evidence for a pathogenic role of IL-17 and Th17 cells, which are part of the CD4+ T-cell subset. Giant cell arteritis occurs in individuals over 50 years of age and many have relative contraindications to glucocorticoid therapy, which today still represents the mainstay therapy. Despite the approval of tocilizumab, which targets the IL-6 receptor, a high demand for glucocorticoid-sparing agents remains that combine the effective suppression of the acute inflammation observed in giant cell arteritis with a safety profile that matches the needs of an older patient population. The first results from a phase II proof-of-principle study (TitAIN) support an optimistic outlook on a potential new treatment option with secukinumab in giant cell arteritis.

AIEC-dependent pathogenic Th17 cell transdifferentiation in Crohn's disease is suppressed by rfaP and ybaT deletion

Mucosal enrichment of the Adherent-Invasive E. coli (AIEC) pathotype and the expansion of pathogenic IFNγ-producing Th17 (pTh17) cells have been linked to Crohn's Disease (CD) pathogenesis. However, the molecular pathways underlying the AIEC-dependent pTh17 cell transdifferentiation in CD patients remain elusive. To this aim, we created and functionally screened a transposon AIEC mutant library of 10.058 mutants to identify the virulence determinants directly implicated in triggering IL-23 production and pTh17 cell generation. pTh17 cell transdifferentiation was assessed in functional assays by co-culturing AIEC-infected human dendritic cells (DCs) with autologous conventional Th17 (cTh17) cells isolated from blood of Healthy Donors (HD) or CD patients. AIEC triggered IL-23 hypersecretion and transdifferentiation of cTh17 into pTh17 cells selectively through the interaction with CD-derived DCs. Moreover, the chronic release of IL-23 by AIEC-colonized DCs required a continuous IL-23 neutralization to significantly reduce the AIEC-dependent pTh17 cell differentiation. The multi-step screenings of the AIEC mutant's library revealed that deletion of ybaT or rfaP efficiently hinder the IL-23 hypersecretion and hampered the AIEC-dependent skewing of protective cTh17 into pathogenic IFNγ-producing pTh17 cells. Overall, our findings indicate that ybaT (inner membrane transport protein) and rfaP (LPS-core heptose kinase) represent novel and attractive candidate targets to prevent chronic intestinal inflammation in CD.

T helper cell subsets: diversification of the field

Polarized T helper cell (Th cell) responses are important determinants of host protection. Th cell subsets tailor their functional repertoire of cytokines to their cognate antigens to efficiently contribute to their clearance. In contrast, in settings of immune abrogation, these polarized cytokine patterns of Th cells can mediate tissue damage and pathology resulting in allergy or autoimmunity. Recent technological developments in single-cell genomics and proteomics as well as advances in the high-dimensional bioinformatic analysis of complex datasets have challenged the prevailing Th cell subset classification into Th1, Th2, Th17, and other subsets. Additionally, systems immunology approaches have revealed that instructive input from the peripheral tissue microenvironment can have differential effects on the overall phenotype and molecular wiring of Th cells depending on their spatial distribution. Th cells from the blood or secondary lymphoid organs are therefore expected to follow distinct rules of regulation. In this review, the functional heterogeneity of Th cell subsets will be reviewed in the context of new technological developments and T-cell compartmentalization in tissue niches. This work will especially focus on challenges to the traditional boundaries of Th cell subsets and will discuss the underlying regulatory checkpoints, which could reveal new therapeutic strategies for various immune-mediated diseases.

Therapeutic targeting of vimentin by ALD-R491 impacts multiple pathogenic processes to attenuate acute and chronic colitis in mice

BACKGROUND

Vimentin, an intermediate filament protein, crucially contributes to the pathogenesis of inflammatory bowel disease (IBD) by interacting with genetic risk factors, facilitating pathogen infection, and modulating both innate and adaptive immune responses. This study aimed to demonstrate preclinical proof-of-concept for targeting vimentin therapeutically in IBD across diverse etiologies.

METHODS

The small molecule compound ALD-R491 was assessed for vimentin binding using microscale thermophoresis, off-target effects via Eurofins screening, and therapeutic effects in mice with dextran sulfate sodium (DSS)-induced acute colitis and in IL-10 KO with spontaneous colitis. Parameters measured included body weight, survival, disease activity, colon length, and histology. The study analyzed intestinal proinflammatory cytokines, Th17/Treg cells, and epithelial barrier molecules, along with gut microbiota profiling.

RESULTS

ALD-R491 specifically bound vimentin with a dissociation constant (KD) of 328 ± 12.66 nM and no off-target effects. In the DSS model, orally administered ALD-R491 exhibited dose-dependent therapeutic effects, superior to 5-ASA and Tofacitinib. In the IL-10 KO model, ALD-R491 significantly delayed colitis onset and progression, with near-zero disease activity index scores over a 15-week treatment. ALD-R491 consistently showed in both models a reduced proinflammatory cytokine expression, including TNF-α, IL-1β, IL-6, IL-17, IL-22, a rebalanced Th17/Treg axis by reducing RORγt while enhancing FoxP3 expression, and an improved epithelial barrier integrity by increasing intestinal expressions of Mucin-2, ZO-1 and Claudin5. The intestinal dysbiosis was restored with enriched presence of probiotics.

CONCLUSIONS

Targeting vimentin exhibits significant therapeutic effects on various facets of IBD pathogenesis, representing a compelling approach for the development of highly effective treatments in IBD.

Sending a Message: Use of mRNA Vaccines to Target the Tumor Immune Microenvironment

While cancer immunotherapies have become central to treatment, challenges associated with the ability of tumors to evade the immune system remain significant obstacles. At the heart of this issue is the tumor immune microenvironment, the complex interplay of the tumor microenvironment and the immune response. Recent advances in mRNA cancer vaccines represent major progress towards overcoming some of the challenges posed by deleterious components of the tumor immune microenvironment. Indeed, major breakthroughs in mRNA vaccine technology, such as the use of replacement nucleotides and lipid nanoparticle delivery, led to the vital success of mRNA vaccine technology in fighting COVID-19. This has in turn generated massive additional interest and investment in the platform. In this review, we detail recent research in the nature of the tumor immune microenvironment and in mRNA cancer vaccines and discuss applications by which mRNA cancer vaccines, often in combination with various adjuvants, represent major areas of potential in overcoming tumor immune microenvironment-imposed obstacles. To this end, we also review current mRNA cancer vaccine clinical trials.

Intricacies of TGF-β signaling in Treg and Th17 cell biology

Balanced immunity is pivotal for health and homeostasis. CD4+ helper T (Th) cells are central to the balance between immune tolerance and immune rejection. Th cells adopt distinct functions to maintain tolerance and clear pathogens. Dysregulation of Th cell function often leads to maladies, including autoimmunity, inflammatory disease, cancer, and infection. Regulatory T (Treg) and Th17 cells are critical Th cell types involved in immune tolerance, homeostasis, pathogenicity, and pathogen clearance. It is therefore critical to understand how Treg and Th17 cells are regulated in health and disease. Cytokines are instrumental in directing Treg and Th17 cell function. The evolutionarily conserved TGF-β (transforming growth factor-β) cytokine superfamily is of particular interest because it is central to the biology of both Treg cells that are predominantly immunosuppressive and Th17 cells that can be proinflammatory, pathogenic, and immune regulatory. How TGF-β superfamily members and their intricate signaling pathways regulate Treg and Th17 cell function is a question that has been intensely investigated for two decades. Here, we introduce the fundamental biology of TGF-β superfamily signaling, Treg cells, and Th17 cells and discuss in detail how the TGF-β superfamily contributes to Treg and Th17 cell biology through complex yet ordered and cooperative signaling networks.

Memory Th17 cell-mediated protection against lethal secondary pneumococcal pneumonia following influenza infection

Streptococcus pneumoniae (Sp) frequently causes secondary pneumonia after influenza A virus (IAV) infection, leading to high morbidity and mortality worldwide. Concomitant pneumococcal and influenza vaccination improves protection against coinfection but does not always yield complete protection. Impaired innate and adaptive immune responses have been associated with attenuated bacterial clearance in influenza virus-infected hosts. In this study, we showed that preceding low-dose IAV infection caused persistent Sp infection and suppression of bacteria-specific T-helper type 17 (Th17) responses in mice. Prior Sp infection protected against subsequent IAV/Sp coinfection by improving bacterial clearance and rescuing bacteria-specific Th17 responses in the lungs. Furthermore, blockade of IL-17A by anti-IL-17A antibodies abrogated the protective effect of Sp preinfection. Importantly, memory Th17 responses induced by Sp preinfection overcame viral-driven Th17 inhibition and provided cross-protection against different Sp serotypes following coinfection with IAV. These results indicate that bacteria-specific Th17 memory cells play a key role in providing protection against IAV/Sp coinfection in a serotype-independent manner and suggest that a Th17-based vaccine would have excellent potential to mitigate disease caused by coinfection. IMPORTANCE Streptococcus pneumoniae (Sp) frequently causes secondary bacterial pneumonia after influenza A virus (IAV) infection, leading to increased morbidity and mortality worldwide. Current pneumococcal vaccines induce highly strain-specific antibody responses and provide limited protection against IAV/Sp coinfection. Th17 responses are broadly protective against Sp single infection, but whether the Th17 response, which is dramatically impaired by IAV infection in naïve mice, might be effective in immunization-induced protection against pneumonia caused by coinfection is not known. In this study, we have revealed that Sp-specific memory Th17 cells rescue IAV-driven inhibition and provide cross-protection against subsequent lethal coinfection with IAV and different Sp serotypes. These results indicate that a Th17-based vaccine would have excellent potential to mitigate disease caused by IAV/Sp coinfection.

DNA methylation patterns in CD4+ T-cells separate psoriasis patients from healthy controls, and skin psoriasis from psoriatic arthritis

Background

Psoriasis is an autoimmune/inflammatory disorder primarily affecting the skin. Chronic joint inflammation triggers the diagnosis of psoriatic arthritis (PsA) in approximately one-third of psoriasis patients. Although joint disease typically follows the onset of skin psoriasis, in around 15% of cases it is the initial presentation, which can result in diagnostic delays. The pathophysiological mechanisms underlying psoriasis and PsA are not yet fully understood, but there is evidence pointing towards epigenetic dysregulation involving CD4+ and CD8+ T-cells.

Objectives

The aim of this study was to investigate disease-associated DNA methylation patterns in CD4+ T-cells from psoriasis and PsA patients that may represent potential diagnostic and/or prognostic biomarkers.

Methods

PBMCs were collected from 12 patients with chronic plaque psoriasis and 8 PsA patients, and 8 healthy controls. CD4+ T-cells were separated through FACS sorting, and DNA methylation profiling was performed (Illumina EPIC850K arrays). Bioinformatic analyses, including gene ontology (GO) and KEGG pathway analysis, were performed using R. To identify genes under the control of interferon (IFN), the Interferome database was consulted, and DNA Methylation Scores were calculated.

Results

Numbers and proportions of CD4+ T-cell subsets (naïve, central memory, effector memory, CD45RA re-expressing effector memory cells) did not vary between controls, skin psoriasis and PsA patients. 883 differentially methylated positions (DMPs) affecting 548 genes were identified between controls and "all" psoriasis patients. Principal component and partial least-squares discriminant analysis separated controls from skin psoriasis and PsA patients. GO analysis considering promoter DMPs delivered hypermethylation of genes involved in "regulation of wound healing, spreading of epidermal cells", "negative regulation of cell-substrate junction organization" and "negative regulation of focal adhesion assembly". Comparing controls and "all" psoriasis, a majority of DMPs mapped to IFN-related genes (69.2%). Notably, DNA methylation profiles also distinguished skin psoriasis from PsA patients (2,949 DMPs/1,084 genes) through genes affecting "cAMP-dependent protein kinase inhibitor activity" and "cAMP-dependent protein kinase regulator activity". Treatment with cytokine inhibitors (IL-17/TNF) corrected DNA methylation patterns of IL-17/TNF-associated genes, and methylation scores correlated with skin disease activity scores (PASI).

Conclusion

DNA methylation profiles in CD4+ T-cells discriminate between skin psoriasis and PsA. DNA methylation signatures may be applied for quantification of disease activity and patient stratification towards individualized treatment.

The protective and pathogenic role of Th17 cell plasticity and function in the tumor microenvironment

At the turn of the century, researchers discovered a unique subtype of T helper cells that secretes IL-17 and defined it as Th17. The latest study found that Th17 cells play both positive and negative definitive roles in the regulation of antitumor immune responses. Although the function of Th17 in the tumor microenvironment remains poorly understood, more and more studies have shown that this paradoxical dual role is closely related to the plasticity of Th17 cells in recent decades. Further understanding of the characteristics of Th17 cells in the tumor microenvironment could yield novel and useful therapeutic approaches to treat cancer. In this review, we further present the high plasticity of Th17 cells and the function of Th17-producing IL-17 in tumor immunity.

Markers and makers of NKT17 cells

Invariant natural killer T (iNKT) cells are thymus-generated innate-like αβ T cells that undergo terminal differentiation in the thymus. Such a developmental pathway differs from that of conventional αβ T cells, which are generated in the thymus but complete their functional maturation in peripheral tissues. Multiple subsets of iNKT cells have been described, among which IL-17-producing iNKT cells are commonly referred to as NKT17 cells. IL-17 is considered a proinflammatory cytokine that can play both protective and pathogenic roles and has been implicated as a key regulatory factor in many disease settings. Akin to other iNKT subsets, NKT17 cells acquire their effector function during thymic development. However, the cellular mechanisms that drive NKT17 subset specification, and how iNKT cells in general acquire their effector function prior to antigen encounter, remain largely unknown. Considering that all iNKT cells express the canonical Vα14-Jα18 TCRα chain and all iNKT subsets display the same ligand specificity, i.e., glycolipid antigens in the context of the nonclassical MHC-I molecule CD1d, the conundrum is explaining how thymic NKT17 cell specification is determined. Mapping of the molecular circuitry of NKT17 cell differentiation, combined with the discovery of markers that identify NKT17 cells, has provided new insights into the developmental pathway of NKT17 cells. The current review aims to highlight recent advances in our understanding of thymic NKT17 cell development and to place these findings in the larger context of iNKT subset specification and differentiation.

Arterial wall fibrosis in Takayasu arteritis and its potential for therapeutic modulation

Arterial wall damage in Takayasu arteritis (TAK) can progress despite immunosuppressive therapy. Vascular fibrosis is more prominent in TAK than in giant cell arteritis (GCA). The inflamed arterial wall in TAK is infiltrated by M1 macrophages [which secrete interleukin-6 (IL-6)], which transition to M2 macrophages once the inflammation settles. M2 macrophages secrete transforming growth factor beta (TGF-β) and glycoprotein non-metastatic melanoma protein B (GPNMB), both of which can activate fibroblasts in the arterial wall adventitia. Mast cells in the arterial wall of TAK also activate resting adventitial fibroblasts. Th17 lymphocytes play a role in both TAK and GCA. Sub-populations of Th17 lymphocytes, Th17.1 lymphocytes [which secrete interferon gamma (IFN-γ) in addition to interleukin-17 (IL-17)] and programmed cell death 1 (PD1)-expressing Th17 (which secrete TGF-β), have been described in TAK but not in GCA. IL-6 and IL-17 also drive fibroblast activation in the arterial wall. The Th17 and Th1 lymphocytes in TAK demonstrate an activation of mammalian target organ of rapamycin 1 (mTORC1) driven by Notch-1 upregulation. A recent study reported that the enhanced liver fibrosis score (derived from serum hyaluronic acid, tissue inhibitor of metalloproteinase 1, and pro-collagen III amino-terminal pro-peptide) had a moderate-to-strong correlation with clinically assessed and angiographically assessed vascular damage. In vitro experiments suggest the potential to target arterial wall fibrosis in TAK with leflunomide, tofacitinib, baricitinib, or mTORC1 inhibitors. Since arterial wall inflammation is followed by fibrosis, a strategy of combining immunosuppressive agents with drugs that have an antifibrotic effect merits exploration in future clinical trials of TAK.

Niosomal Curcumin Suppresses IL17/IL23 Immunopathogenic Axis in Skin Lesions of Psoriatic Patients: A Pilot Randomized Controlled Trial

Psoriasis (PS) is characterized by hyperplasia of epidermis and infiltration of immune cells in the dermis. A negligible susceptibility of hypodermic permeation for local anti-inflammatory remedies is one of the major causes of medication failures. Although curcumin (CUR) has indicated effectiveness in treatment of inflammation, its successful permeation through the stratum corneum is yet a challenging issue. Therefore, niosome (NIO) nanoparticles were used as curcumin carriers to enhance its delivery and anti-inflammatory effects. Curcumin-niosome (CUR-NIO) formulations were constructed by the thin-film-hydration (TFH) technique and were added to hyaluronic acid and Marine-collagen gel-based formulation. Five mild-to-moderate PS patients (18-60 years) with PASI scores < 30 with symmetrical and similar lesions were included in the study. The prepared formulation (CUR 15 µM) was topically administered for 4 weeks on the skin lesions, in comparison to the placebo. Clinical skin manifestations were monitored and skin punches were obtained for further gene expression analyses. There was a significant reduction in redness, scaling, and an apparent improvement in CUR-NIO-treated group in comparison to the placebo-treated counterpart. The gene expression analyses resulted in significantly downregulation of IL17, IL23, IL22, and TNFα, S100A7, S100A12, and Ki67 in CUR-NIO-treated lesions. Consequently, CUR-NIO could provide therapeutic approaches for the patients with mild-to-moderate PS by suppressing the IL17/IL23 immunopathogenic axis.

Regulatory factors involved in Th17/Treg cell balance of immune thrombocytopenia

Immune thrombocytopenia is a common heterogeneous autoimmune disease that is characterized by decreasing peripheral blood platelet counts and increasing risk of bleeding. Studies have shown that an imbalance between T helper 17 (Th17) and Regulatory T (Treg) cells differentiated from CD4+T-cells is a key factor influencing the development and pathogenesis of immune thrombocytopenia. Th17 cells promote the development of chronic inflammatory disorders and induce autoimmune diseases, whereas Treg cells regulate immune homeostasis and prevent autoimmune diseases. Several regulators affecting the production and maintenance of these cells are also essential for proper regulation of Th17/Treg balance; these regulatory factors include cell surface proteins, miRNAs, and cytokine signaling. In this review, we focus on the function and role of balance between Th17 and Treg cells in immune thrombocytopenia, the regulatory factors, and therapeutic goals of this balance in immune thrombocytopenia.

Human IL-23 is essential for IFN-γ-dependent immunity to mycobacteria

Patients with autosomal recessive (AR) IL-12p40 or IL-12Rβ1 deficiency display Mendelian susceptibility to mycobacterial disease (MSMD) due to impaired IFN-γ production and, less commonly, chronic mucocutaneous candidiasis (CMC) due to impaired IL-17A/F production. We report six patients from four kindreds with AR IL-23R deficiency. These patients are homozygous for one of four different loss-of-function IL23R variants. All six patients have a history of MSMD, but only two suffered from CMC. We show that IL-23 induces IL-17A only in MAIT cells, possibly contributing to the incomplete penetrance of CMC in patients unresponsive to IL-23. By contrast, IL-23 is required for both baseline and Mycobacterium-inducible IFN-γ immunity in both Vδ2+ γδ T and MAIT cells, probably contributing to the higher penetrance of MSMD in these patients. Human IL-23 appears to contribute to IL-17A/F-dependent immunity to Candida in a single lymphocyte subset but is required for IFN-γ-dependent immunity to Mycobacterium in at least two lymphocyte subsets.

Antigen-specific memory Th17 cells promote cross-protection against nontypeable Haemophilus influenzae after mild influenza A virus infection

Secondary bacterial pneumonia after influenza A virus (IAV) infection is the leading cause of hospitalization and death associated with IAV infection worldwide. Nontypeable Haemophilus influenzae (NTHi) is one of the most common causes of secondary bacterial pneumonia. Current efforts to develop vaccines against NTHi infection focus on inducing antibodies but are hindered by antigenic diversity among NTHi strains. Therefore, we investigated the contribution of the memory T helper type 17 (Th17) response in protective immunity against IAV/NTHi coinfection. We observed that even a mild IAV infection impaired the NTHi-specific Th17 response and increased morbidity and mortality compared with NTHi monoinfected mice. However, pre-existing memory NTHi-specific Th17 cells induced by a previous NTHi infection overcame IAV-driven Th17 inhibition and were cross-protective against different NTHi strains. Last, mice immunized with a NTHi protein that induced a strong Th17 memory response were broadly protected against diverse NTHi strains after challenge with coinfection. These results indicate that vaccination that limits IAV infection to mild disease may be insufficient to eliminate the risk of a lethal secondary bacterial pneumonia. However, NTHi-specific memory Th17 cells provide serotype-independent protection despite an ongoing IAV infection and demonstrate the advantage of developing broadly protective Th17-inducing vaccines against secondary bacterial pneumonia.

Evidence for Biologic Drug Modifying Anti-Rheumatoid Drugs and Association with Cardiovascular Disease Risk Mitigation in Inflammatory Arthritis

Systemic auto-immune inflammatory arthritides are associated with increased cardiovascular (CV) risk compared to those without these conditions, and is a leading cause of morbidity and mortality. Newer biologic drug modifying antirheumatoid drugs (bDMARD) and small molecules have transformed treatment paradigms enabling tighter control of disease activity and in some cases, remission. There is evidence to suggest that the majority of bDMARDs may also reduce cardiovascular risk, although prospective interventional data remain sparse. Additionally, recent results raise concern for treatments targeting specific pathways that may negatively affect cardiovascular risk. This review will cover key biologic pathways targeted in rheumatoid arthritis, psoriatic arthritis, and spondyloarthropathies.

GM-CSF-producing CCR2+ CCR6+ Th17 cells are pathogenic in dextran sodium sulfate-induced colitis model in mice

Although excessive immune responses by Th17 cells, a helper T cell subset, are implicated in the pathogenesis of inflammatory bowel disease (IBD), the mechanism by which its localization in an inflamed colon is regulated remains unclear. Chemokines and their receptors are involved in the pathogenesis of IBD, however, the relative significance of each receptor on Th17 cells remains unknown. We generated C-C motif chemokine receptor 2 (CCR2) knockout (KO) and CCR6 KO mice in the syngeneic background using the CRISPR/Cas9 system and found that the phenotypes of experimental colitis worsened in both mutant mice. Surprisingly, the phenotype of colitis in CCR2/CCR6-double knockout (CCR2/6 DKO) mice was opposite to that of the single-deficient mice, with significantly milder experimental colitis (p < .05). The same was true for the symptoms in CCR6 KO mice, but not in wild type mice treated with a CCR2 inhibitor, propagermanium. Colonic CCR2⁺ CCR6⁺ Th17 cells produced a potentially pathogenic cytokine GM-CSF whose levels in the gut were significantly reduced in CCR2/6 DKO mice (p < .05). These results suggest that GM-CSF-producing CCR2⁺ CCR6⁺ Th17 cells are pathogenic and are attracted to the inflamed colon by either CCR2 or CCR6 gradient, which subsequently exacerbates experimental colitis in mice.

Pellino-1 promotes intrinsic activation of skin-resident IL-17A-producing T cells in psoriasis

BACKGROUND

Psoriasis is a chronically relapsing inflammatory skin disease primarily perpetuated by skin-resident IL-17-producing T (T17) cells. Pellino-1 (Peli1) belongs to a member of E3 ubiquitin ligase mediating immune receptor signaling cascades, including nuclear factor kappa-light-chain enhancer of activated B cells (NF-κB) pathway.

OBJECTIVE

We explored the potential role of Peli1 in psoriatic inflammation in the context of skin-resident T17 cells.

METHODS

We performed single-cell RNA sequencing of relapsing and resolved psoriatic lesions with analysis for validation data set of psoriasis. Mice with systemic and conditional depletion of Peli1 were generated to evaluate the role of Peli1 in imiquimod-induced psoriasiform dermatitis. Pharmacologic inhibition of Peli1 in human CD4⁺ T cells and ex vivo human skin cultures was also examined to evaluate its potential therapeutic implications.

RESULTS

Single-cell RNA sequencing analysis revealed distinct T-cell subsets in relapsing psoriasis exhibiting highly enriched gene signatures for (1) tissue-resident T cells, (2) T17 cells, and (3) NF-κB signaling pathway including PELI1. Peli1-deficient mice were profoundly protected from psoriasiform dermatitis, with reduced IL-17A production and NF-κB activation in γδ T17 cells. Mice with conditional depletion of Peli1 treated with FTY720 revealed that Peli1 was intrinsically required for the skin-resident T17 cell immune responses. Notably, pharmacologic inhibition of Peli1 significantly ameliorated murine psoriasiform dermatitis and IL-17A production from the stimulated human CD4⁺ T cells and ex vivo skin explants modeling psoriasis.

CONCLUSION

Targeting Peli1 would be a promising therapeutic strategy for psoriasis by limiting skin-resident T17 cell immune responses.

Understanding the development of Th2 cell-driven allergic airway disease in early life

Allergic diseases, including atopic dermatitis, allergic rhinitis, asthma, and food allergy, are caused by abnormal responses to relatively harmless foreign proteins called allergens found in pollen, fungal spores, house dust mites (HDM), animal dander, or certain foods. In particular, the activation of allergen-specific helper T cells towards a type 2 (Th2) phenotype during the first encounters with the allergen, also known as the sensitization phase, is the leading cause of the subsequent development of allergic disease. Infants and children are especially prone to developing Th2 cell responses after initial contact with allergens. But in addition, the rates of allergic sensitization and the development of allergic diseases among children are increasing in the industrialized world and have been associated with living in urban settings. Particularly for respiratory allergies, greater susceptibility to developing allergic Th2 cell responses has been shown in children living in urban environments containing low levels of microbial contaminants, principally bacterial endotoxins [lipopolysaccharide (LPS)], in the causative aeroallergens. This review highlights the current understanding of the factors that balance Th2 cell immunity to environmental allergens, with a particular focus on the determinants that program conventional dendritic cells (cDCs) toward or away from a Th2 stimulatory function. In this context, it discusses transcription factor-guided functional specialization of type-2 cDCs (cDC2s) and how the integration of signals derived from the environment drives this process. In addition, it analyzes observational and mechanistic studies supporting an essential role for innate sensing of microbial-derived products contained in aeroallergens in modulating allergic Th2 cell immune responses. Finally, this review examines whether hyporesponsiveness to microbial stimulation, particularly to LPS, is a risk factor for the induction of Th2 cell responses and allergic sensitization during infancy and early childhood and the potential factors that may affect early-age response to LPS and other environmental microbial components.

Deciphering the mechanism of Tinospora cordifolia extract on Th17 cells through in-depth transcriptomic profiling and in silico analysis

Naive CD4⁺ T cells differentiate into effector (Th1, Th2, Th17) cells and immunosuppressive (Treg) cells upon antigenic stimulation in the presence of a specific cytokine milieu. The T cell in vitro culture system provides a very efficient model to study compounds' therapeutic activity and mechanism of action. Tinospora cordifolia (Willd.) Hook.f. & Thomson (Family. Menispermaceae) is one of the widely used drugs in Ayurveda (ancient Indian system of medicine) for various ailments such as inflammatory conditions, autoimmune disorders, and cancer as well as for promoting general health. In vitro and in vivo studies on immune cells comprising dendritic cells, macrophages, and B cells suggest its immune-modulating abilities. However, to date, the effect of T. cordifolia on individual purified and polarized T cell subsets has not been studied. Studying drug effects on T cell subsets is needed to understand their immunomodulatory mechanism and to develop treatments for diseases linked with T cell abnormalities. In this study, we examined the immunomodulatory activity of T. cordifolia on primary CD4⁺ T cells, i.e., Th1, Th17, and iTreg cells. An aqueous extract of T. cordifolia was non-cytotoxic at concentrations below 1500 µg/ml and moderately inhibited the proliferation of naive CD4⁺ T cells stimulated with anti-CD3ε and anti-CD28 for 96 h. T. cordifolia treatment of naive CD4⁺ T cells differentiated under Th17-polarizing conditions exhibited reduced frequency of IL-17 producing cells with inhibition of differentiation and proliferation. For the first time, in-depth genome-wide expression profiling of T. cordifolia treated naive CD4⁺ T cells, polarized to Th17 cells, suggests the broad-spectrum activity of T. cordifolia. It shows inhibition of the cytokine-receptor signaling pathway, majorly via the JAK-STAT signaling pathway, subsequently causing inhibition of Th17 cell differentiation, proliferation, and effector function. Additionally, the molecular docking studies of the 69 metabolites of T. cordifolia further substantiate the inhibitory activity of T. cordifolia via the cytokine-receptor signaling pathway. Furthermore, in vitro polarized Th1 and iTreg cells treated with T. cordifolia extract also showed reduced IFN-γ production and FoxP3 expression, respectively. This study provides insight into the plausible mechanism/s of anti-inflammatory activity of T. cordifolia involving T cells, mainly effective in Th17-associated autoimmune and inflammatory diseases.

The Role of Inflammation in the Pathogenesis of Psoriasis

"Psoriasis is a chronic inflammatory skin condition with genetic determinism characterized by the presence of welldefined, erythematous plaques, covered by white, pearly, stratified scales, located on the extension areas, the skin of the scalp, intertriginous regions. The origin of psoriasis is multifactorial, involving hereditary and environmental pathogenic mechanisms. It is triggered by various risk factors involving a variety of processes, such as inflammation, antigen presentation, cell signaling, and transcriptional regulation. "

Helicobacter pylori Immune Response in Children Versus Adults

H. pylori is perhaps the most prevalent human pathogen worldwide and infects almost half of the world's population. Despite the decreasing prevalence of infection overall, it is significant in developing countries. Most infections are acquired in childhood and persist for a lifetime unless treated. Children are often asymptomatic and often develop a tolerogenic immune response that includes T regulatory cells and their products, immunosuppressive cytokines, such as interleukin (IL)-10, and transforming growth factor-β (TGF-β). This contrasts to the gastric immune response seen in H. pylori-infected adults, where the response is mainly inflammatory, with predominant Th1 and Th17 cells, as well as, inflammatory cytokines, such as TNF-α, IFN-γ, IL-1, IL-6, IL-8, and IL-17. Therefore, compared to adults, infected children generally have limited gastric inflammation and peptic ulcer disease. H. pylori surreptitiously subverts immune defenses to persist in the human gastric mucosa for decades. The chronic infection might result in clinically significant diseases in adults, such as peptic ulcer disease, gastric adenocarcinoma, and mucosa-associated lymphoid tissue lymphoma. This review compares the infection in children and adults and highlights the H. pylori virulence mechanisms responsible for the pathogenesis and immune evasion.

The role of PAF in immunopathology: From immediate hypersensitivity reactions to fungal defense

Platelet-activating factor (PAF, 1-alkyl-2-acetyl-sn-glycero-3-phosphorylcholine) was discovered when the mechanisms involved in the deposition of immune complex in tissues were being scrutinized in the experimental model of rabbit serum sickness. The initial adscription of PAF to IgE-dependent anaphylaxis was soon extended after disclosing its release from phagocytes stimulated by calcium mobilizing agents, formylated peptides, and phagocytosable particles. This explains why ongoing research in the field turned to the analysis of immune cell types and stimuli involved in PAF production with the purpose of establishing its role in pathology. This was spurred by the identification of the chemical structure of PAF and the enzymic mechanisms involved in its biosynthesis and degradation, which showed commonalities with those involved in eicosanoid production and the Lands' cycle of phospholipid fatty acid remodeling. The reassignment of PAF function in immunopathology is explained by the finding that the most robust mechanisms leading to PAF production are associated with opsonic and non-opsonic phagocytosis, depending on the cell type. While polymorphonuclear leukocytes exhibit opsonic phagocytosis, monocyte-derived dendritic cells show a marked preference for non-opsonic phagocytosis associated with C-type lectin receptors. This is particularly relevant to the defense against fungal invasion and explains why PAF exerts an autocrine feed-forwarding mechanism required for the selective expression of some cytokines.

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.

The regulatory mechanism and potential application of IL-23 in autoimmune diseases

IL-23 is a heterodimeric pro-inflammatory cytokine secreted by dendritic cells and macrophages that belongs to the IL-12 family. It has pro-inflammatory effects and is a key cytokine and upstream regulatory cytokine involved in protective immune responses, stimulating the differentiation and proliferation of downstream effectors such as Th17 cells. It is expressed in various autoimmune diseases such as psoriasis, systemic lupus erythematosus (SLE), rheumatoid arthritis (RA). The IL-23/TH17 axis formed by IL-23 and TH17 has been confirmed to participate in autoimmune diseases pathogenesis. IL-23R is the receptor for IL-23 and plays an activating role. Targeting IL-23 is currently the main strategy for the treatment of various autoimmune diseases. In this review we summarized the mechanism of action and clinical application potential of IL-23 in autoimmune diseases by summarizing the latest research results and reviewing the literature, which would help to further understand IL-23 and provide a theoretical basis for future clinical targeting and drug development.

Stat5-/- CD4+ T cells elicit anti-melanoma effect by CD4+ T cell remolding and Notch1 activation

Signal transducers and activators of transcription 5 (Stat5) is known to engage in regulating the differentiation and effector function of various subsets of T helper cells. However, how Stat5 regulates the antitumor activity of tumor-infiltrating CD4⁺ T cells is largely unknown. Here, we showed that mice with specific deletion of Stat5 in CD4⁺ T cells were less susceptible to developing subcutaneous and lung metastatic B16 melanoma with CD4⁺ tumor-infiltrating lymphocytes (TILs) remolding. Especially, we confirmed that Stat5-deficient CD4⁺ naïve T cells were prone to polarization of two subtypes of Th17 cells: IFN-γ⁺ and IFN-γ^- Th17 cells, which exhibited increased anti-melanoma activity through enhanced activation of Notch1 pathway compared with wild type Th17 cells. Our study therefore revealed a novel function of Stat5 in regulating tumor-specific Th17 cell differentiation and function in melanoma. This study also provided a new possibility for targeting Stat5 and other Th17-associated pathways to develop novel immunotherapies for melanoma patients.

Identification and validation of the role of c-Myc in head and neck squamous cell carcinoma

Background

Many studies have shown that c-Myc plays a critical role in tumorigenesis. However, the molecular role of c-Myc in head and neck squamous cell carcinoma (HNSC) remains unclear.

Methods

Several biological databases, including UALCAN, TIMER2.0, TCGAportal, GEPIA, KM plotter, OncoLnc, LinkedOmics, GSCA, and TCIA, were used to analyze the molecular role of c-Myc in HNSC. The expression levels of c-Myc were validated by real-time PCR (RT–PCR) and Western blot in CAL-27 cells.

Results

The expression of c-Myc mRNA were significantly increased in HPV-negative HNSC tissues. The expression of c-Myc gene level was correlated with TP53 mutation status. HNSC also showed hypomethylated c-Myc compared with normal tissues. c-Myc was identified as an ominous prognostic factor for HNSC patients and correlated with immune infiltrating levels. Moreover, high c-Myc expression was associated with decreased expression of a series of immune checkpoints, resulting in a dampened immune response. c-Myc potentially mediated IL-17 signaling pathway and Th1 and Th2 cell differentiation. Inhibition of c-Myc expression increased apoptosis of CAL-27 cells.

Conclusions

These findings suggest a new mechanism of c-Myc in the prognosis of HNSC, implying the potential of c-Myc as a therapeutic target for HNSC patients.

Diyabetik Periferik Polinöropatili Hastalarda İnterlökin-23R Gen Polimofizmleri

Amaç: Diyabetik nöropatinin patogenezinde proinflamatuar ve nörovasküler değişiklikler suçlanmaktadır. Diyabetin vasküler inflamasyonu tetiklediği kabul edilse de inflamasyonun da diyabeti tetikleyebileceği öne sürülmüştür. İnterlökin-23 (IL-23) aktive makrofajlar ve dendritik hücreler tarafından salgılanan proinflamatuar bir sitokindir. Interleukin-23R'nin kronik inflamatuar hastalıklarda kritik bir rolü olduğu bilinmektedir. Bu çalışmanın amacı, IL-23R polimorfizmi ile diyabetik periferik nöropati arasındaki ilişkiyi incelemektir. Yöntem: Nöroloji polikliniğine başvuran 50 diyabetik periferik nöropati hastası ve hasta grubuna yaş ve cinsiyet açısından uyumlu 52 sağlıklı kontrol çalışmaya dahil edildi. Çalışmaya katılmayı kabul eden gönüllülerin tamamına elektromiyografi uygulandı ve EDTA'lı tüplere 2 ml kan örneği alındı. Pyrosequencing yöntemi ile IL-23R gen polimorfizmi analiz edildi. Bulgular: IL-23R gen varyantları rs2201841, rs199542433, rs201052419, rs11209026 diyabetik periferik nöropati (DPN) hastalarında ve kontrol grubunda analiz edildi. IL23R polimorfizmleri sıklıkları açısından hasta ve kontrol grupları arasında anlamlı bir fark saptanmadı. Ancak, odd’s oranlarına bakıldığında, rs2201841'in koruyucu rolü var gibi görünmekte, rs199542433 hem baskın hem de çekinik modellerde ve rs11209026 sadece çekinik modelde, DPN için 10 kata kadar daha yüksek risklerle ilişkili olabileceği görünmektedir. Sonuç: IL-23R gen polimorfizminin birçok otoimmün ve inflamatuar hastalık ile ilişkili olduğu gösterilmiştir. İnflamasyonun diyabet üzerinde önemli bir etkisi olduğu bilinmektedir. Diyabetik periferik nöropatide IL-23R gen polimorfizminin sıklığı anlamlı değildi. Çalışmamız diyabetik periferik nöropatide IL-23R gen polimorfizminin rolünü araştıran tek ve ilk çalışmadır. Etnik köken, genetik çalışmalarda çok önemlidir ve bu çalışmanın başka etnik kökene sahip hastalarda yapılması ve daha geniş çalışma gruplarının alınması, bize ilerisi için daha net bilgiler verecektir.

Immunological effects of anti-IL-17/12/23 therapy in patients with psoriasis complicated by Candida infections

Biologics that block the T-helper-17 pathway are very effective in the treatment of psoriasis and other inflammatory diseases. However, interleukin-17 is also crucial for antifungal host defense, and clinical trial data suggest an increase in the incidence of Candida infections during IL-17 inhibitor (IL-17i) therapy. We investigated the innate and adaptive immune responses of psoriasis patients with a history of skin and/or mucosal candidiasis during IL-17i or IL-12/23i therapy, comparing those responses to healthy controls. Psoriasis patients with IL-17i showed significantly lower CD4+Th1-like (CCR6^-CXCR3⁺CCR4^-) and Th1Th17-like (CD4⁺CCR6⁺CXCR3⁺CCR4^-) cell percentages. Patient cells stimulated with Candida albicans produced significantly lower IL-6 in the IL-12/23i group and IL-1β production in the IL-17i group, while the release of TNF-α and ROS was similar between patients and controls. IFN-γ and IL-10 production in response to several stimuli after 7 days was particularly decreased in patients receiving IL-17i therapy. Finally, after stimulation with the polarizing cytokines IL-1β and IL-23, the Th17 cytokine response was significantly lower in the IL-17i patient group. These innate and adaptive immune response defects can diminish antifungal host immune response and thereby increase susceptibility to candidiasis in patients treated with IL-17i or IL-12/23i.

Guselkumab for the Treatment of Crohn's Disease: Induction Results From the Phase 2 GALAXI-1 Study

BACKGROUND & AIMS

Guselkumab, a selective p19 interleukin-23 antagonist, is approved for the treatment of plaque psoriasis and psoriatic arthritis. This study evaluated the efficacy and safety of guselkumab in patients with moderately to severely active Crohn's disease with inadequate response or intolerance to conventional or biologic therapy.

METHODS

GALAXI-1, a phase 2, double-blind, placebo-controlled study, randomized patients 1:1:1:1:1 to intravenous guselkumab 200 mg, 600 mg, or 1200 mg at weeks 0, 4, and 8; intravenous ustekinumab approximately 6 mg/kg at week 0 and 90 mg subcutaneously at week 8; or placebo. Change from baseline in Crohn's Disease Activity Index score (primary end point), clinical remission, clinical response, Patient Reported Outcomes-2 remission, clinical-biomarker response, endoscopic response (major secondary end points), and safety in guselkumab-treated patients vs placebo were evaluated through week 12. Ustekinumab was a reference arm.

RESULTS

Of 309 patients evaluated, approximately 50% had disease refractory to prior biologic therapy. At week 12, significantly greater reductions in Crohn's Disease Activity Index from baseline (least squares means: 200 mg: -160.4, 600 mg: -138.9, and 1200 mg: -144.9 vs placebo: -36.2; all, P < .05) and significantly greater proportions of patients achieved clinical remission in each guselkumab group vs placebo (Crohn's Disease Activity Index <150; 57.4%, 55.6%, and 45.9% vs 16.4%; all, P < .05). Greater proportions of patients receiving guselkumab achieved clinical response, Patient Reported Outcomes-2 remission, clinical-biomarker response, and endoscopic response at week 12 vs placebo. Efficacy of ustekinumab vs placebo was also demonstrated. Safety event rates were generally similar across treatment groups.

CONCLUSIONS

At week 12, all 3 dose regimens of guselkumab induced greater clinical and endoscopic improvements vs placebo, with a favorable safety profile.

CLINICALTRIALS

gov, Number: NCT03466411.

A Pathogenic Th17/CD38+ Macrophage Feedback Loop Drives Inflammatory Arthritis through TNF-α

The pathobiology of rheumatoid inflammatory diseases, including rheumatoid arthritis (RA) and psoriatic arthritis, involves the interplay between innate and adaptive immune components and resident synoviocytes. Single-cell analyses of patient samples and relevant mouse models have characterized many cellular subsets in RA. However, the impact of interactions between cell types is not fully understood. In this study, we temporally profiled murine arthritic synovial isolates at the single-cell level to identify perturbations similar to those found in human RA. Notably, murine macrophage subtypes like those found in RA patients were expanded in arthritis and linked to promoting the function of Th17 cells in the joint. In vitro experiments identified a capacity for murine macrophages to maintain the functionality and expansion of Th17 cells. Reciprocally, murine Th17 cell-derived TNF-α induced CD38⁺ macrophages that enhanced Th17 functionality. Murine synovial CD38⁺ macrophages were expanded during arthritis, and their depletion or blockade via TNF-α neutralization alleviated disease while reducing IL-17A-producing cells. These findings identify a cellular feedback loop that promotes Th17 cell pathogenicity through TNF-α to drive inflammatory arthritis.

Th17 cells in the liver: balancing autoimmunity and pathogen defense

In addition to carcinogenesis, T helper 17 (Th17) cells (a subtype of CD4 + T lymphocytes) are involved in the acute, chronic, and cirrhotic phases of liver diseases; however, their role in the development and progression of liver diseases remains unclear. It is difficult to elucidate the role of Th17 cells in liver diseases due to their dichotomous nature, i.e., plasticity in terms of pathogenic or host protective function depending on environmental and time phase factors. Moreover, insufficient depletion of Th17 cells by inhibiting the cytokines and transcription factors involved in their production causes difficulties in analyzing their specific role in vitro and in vivo murine models, partially due to complex interaction. This review summarizes the recent progress in understanding the plasticity and function of hepatic Th17 cells and type 3 cytokines.

IL-23 production in human macrophages is regulated negatively by tumor necrosis factor α-induced protein 3 and positively by specificity protein 1 after stimulation of the toll-like receptor 7/8 signaling pathway

The IL-23/IL-17 axis plays an important role in the development of autoimmune diseases, but the mechanism regulating IL-23 production is mainly unknown. We investigated how TNFAIP3 and Sp1 affect IL-23 production by human macrophages after exposure to resiquimod, a TLR7/8 agonist.

IL-23 production was significantly upregulated by resiquimod but only slightly by LPS (a TLR4 agonist). Interestingly, IL-23 levels were significantly attenuated after sequential stimulation with LPS and resiquimod, but IL-12p40 and IL-18 levels were not. TLR4-related factors induced by LPS may regulate IL-23 expression via TLR7/8 signaling. LPS significantly enhanced TNFAIP3 and IRAK-M levels but reduced Sp1 levels. After exposure to resiquimod, RNA interference of TNFAIP3 upregulated IL-23 significantly more than siRNA transfection of IRAK-M did. In contrast, knockdown of Sp1 by RNA interference significantly attenuated IL-23 production. Transfection with siRNA for TNFAIP3 enhanced IL-23 expression significantly. After stimulation with resiquimod, GW7647—an agonist for PPARα (an inducer of NADHP oxidase)—and siRNA for UCP2 (a negative regulator of mitochondrial ROS generation) enhanced TNFAIP3 and reduced IL-23. siRNA for p22phox and gp91phox slightly increased Sp1 levels. However, after exposure to resiquimod siRNA-mediated knockout of DUOX1/2 significantly enhanced Sp1 and IL-23 levels, and decreased TNFα-dependent COX-2 expression. Concomitantly, TNFAIP3 levels was attenuated by DUOX1/2 siRNA. TNFAIP3 and Sp1 levels are reciprocally regulated through ROS generation.

In conclusion, after stimulation of the TLR7/8 signaling pathway IL-23 production in human macrophages is regulated negatively by TNFAIP3.

The Role of Interleukins in the Pathogenesis of Dermatological Immune-Mediated Diseases

Autoimmune inflammatory diseases are primarily characterized by deregulated expression of cytokines, which drive pathogenesis of these diseases. A number of approved and experimental therapies utilize monoclonal antibodies against cytokine proteins. Cytokines can be classified into different families including the interleukins, which are secreted and act on leukocytes, the tumor necrosis factor (TNF) family, as well as chemokine proteins. In this review article, we focus on the interleukin family of cytokines, of which 39 members have been identified to this date. We outline the role of each of these interleukins in the immune system, and various dermatological inflammatory diseases with a focused discussion on the pathogenesis of psoriasis and atopic dermatitis. In addition, we describe the roles of various interleukins in psychiatric, cardiovascular, and gastrointestinal comorbidities. Finally, we review clinical efficacy and safety data from emerging late-phase anti-interleukin therapies under development for psoriasis and atopic dermatitis. Collectively, additional fundamental and clinical research remains necessary to fully elucidate the roles of various interleukin proteins in the pathogenesis of inflammatory dermatologic diseases, and treatment outcomes in patients.

The Tyrosine Kinase Tec Regulates Effector Th17 Differentiation, Pathogenicity, and Plasticity in T-Cell-Driven Intestinal Inflammation

T helper (Th) 17 cells are not only key in controlling infections mediated by extracellular bacteria and fungi but are also triggering autoimmune responses. Th17 cells comprise heterogeneous subsets, some with pathogenic functions. They can cease to secrete their hallmark cytokine IL-17A and even convert to other T helper lineages, a process known as transdifferentiation relying on plasticity. Both pathogenicity and plasticity are tightly linked to IL-23 signaling. Here, we show that the protein tyrosine kinase Tec is highly induced in Th17 cells. Th17 differentiation was enhanced at low interleukin-6 (IL-6) concentrations in absence of Tec, which correlates with increased STAT3 phosphorylation and higher Il23r expression. Therefore, we uncovered a function for Tec in the IL-6 sensing via STAT3 by CD4⁺ T cells, defining Tec as a fine-tuning negative regulator of Th17 differentiation. Subsequently, by using the IL-17A fate mapping mouse combined with in vivo adoptive transfer models, we demonstrated that Tec not only restrained effector Th17 differentiation but also pathogenicity and plasticity in a T-cell intrinsic manner. Our data further suggest that Tec regulates inflammatory Th17-driven immune responses directly impacting disease severity in a T-cell-driven colitis model. Notably, consistent with the in vitro findings, elevated levels of the IL-23 receptor (IL-23R) were observed on intestinal pre- and postconversion Th17 cells isolated from diseased Tec^-/- mice subjected to adoptive transfer colitis, highlighting a fundamental role of Tec in restraining IL-23R expression, likely via the IL-6-STAT3 signaling axis. Taken together, these findings identify Tec as a negative regulator of Th17 differentiation, pathogenicity, and plasticity, contributing to the mechanisms which help T cells to orchestrate optimal immune protection and to restrain immunopathology.

IL-23 orchestrating immune cell activation in arthritis

IL-23 is a cytokine member of the IL-12 superfamily. These heterodimeric cytokines offer broad immune regulatory activity with potential effector function in inflammatory arthritis. IL-23 is a pro-inflammatory cytokine secreted by dendritic cells and macrophages. It plays a key role in both innate and adaptive immunity. By promoting and maintaining T cell differentiation into Th17 T cells, IL-23 is a key player in the pathogenesis of rheumatic diseases. Data from pre-clinical IL-23 knockout models show the major importance of IL-23 in development of arthritis. The induction and maintenance of type 17 cells, which secrete IL-17A and other pro-inflammatory cytokines, contributes to local synovial inflammation and skin inflammation in PsA, and perhaps in RA. Commensurate with this, therapeutic strategies targeting IL-23 have proven efficient in PsA in several studies, albeit not yet in RA.

Advancing the use of genome-wide association studies for drug repurposing

Genome-wide association studies (GWAS) have revealed important biological insights into complex diseases, which are broadly expected to lead to the identification of new drug targets and opportunities for treatment. Drug development, however, remains hampered by the time taken and costs expended to achieve regulatory approval, leading many clinicians and researchers to consider alternative paths to more immediate clinical outcomes. In this Review, we explore approaches that leverage common variant genetics to identify opportunities for repurposing existing drugs, also known as drug repositioning. These approaches include the identification of compounds by linking individual loci to genes and pathways that can be pharmacologically modulated, transcriptome-wide association studies, gene-set association, causal inference by Mendelian randomization, and polygenic scoring.

RORγt agonist synergizes with CTLA-4 antibody to inhibit tumor growth through inhibition of Treg cells via TGF-β signaling in cancer

To date, the overall response rate to checkpoint blockade remains unsatisfactory, partially due to the limited understanding of the tumor immune microenvironment. The retinoic acid-related orphan receptor γt (RORγt) is the key transcription factor of T helper cell 17 (Th17) cells and plays an essential role in tumor immunity. In this study, we used JG-1, a potent and selective small-molecule RORγt agonist to evaluate the therapeutic potential and mechanism of action of targeting RORγt in tumor immunity. JG-1 promotes Th17 cells differentiation and inhibition of regulatory T (Treg) cells differentiation. JG-1 demonstrates robust tumor growth inhibition in multiple syngeneic models and shows a synergic effect with the Cytotoxic T-Lymphocyte Antigen 4 (CTLA-4) antibody. In tumors, JG-1 not only promotes Th17 cells differentiation and increases C-C Motif Chemokine Receptor 6 (CCR6)- Chemokine (C-C motif) ligand 20 (CCL20) expression, but also inhibits both the expression of transforming growth factor-β1 (TGF-β1) and the differentiation and infiltration of Treg cells. In summary, JG-1 is a lead compound showing a potent activity in vitro and robust tumor growth inhibition in vivo with synergetic effects with anti-CTLA-4.

Bacterial Translocation as Inflammatory Driver in Crohn's Disease

Crohn’s disease (CD) is a chronic inflammatory disorder of the gastrointestinal tract responsible for intestinal lesions. The multifactorial etiology attributed to CD includes a combination of environmental and host susceptibility factors, which result in an impaired host–microbe gut interaction. Bacterial overgrowth and dysbiosis, increased intestinal barrier permeability, and altered inflammatory responses in patients with CD have been described in the past. Those events explain the pathogenesis of luminal translocation of bacteria or its products into the blood, a frequent event in CD, which, in turn, favors a sustained inflammatory response in these patients. In this review, we navigate through the interaction between bacterial antigen translocation, permeability of the intestinal barrier, immunologic response of the host, and genetic predisposition as a combined effect on the inflammatory response observed in CD. Several lines of evidence support that translocation of bacterial products leads to uncontrolled inflammation in CD patients, and as a matter of fact, the presence of gut bacterial genomic fragments at a systemic level constitutes a marker for increased risk of relapse among CD patients. Also, the significant percentage of CD patients who lose response to biologic therapies may be influenced by the translocation of bacterial products, which are well-known drivers of proinflammatory cytokine production by host immune cells. Further mechanistic studies evaluating cellular and humoral immune responses, gut microbiota alterations, and genetic predisposition will help clinicians to better control and personalize the management of CD patients in the future.