Distinctive CD39+CD9+ lung interstitial macrophages suppress IL-23/Th17-mediated neutrophilic asthma by inhibiting NETosis.

The IL-23-Th17 axis is responsible for neutrophilic inflammation in various inflammatory diseases. Here, we discover a potential pathway to inhibit neutrophilic asthma. In our neutrophil-dominant asthma (NDA) model, single-cell RNA-seq analysis identifies a subpopulation of CD39+CD9+ interstitial macrophages (IMs) suppressed by IL-23 in NDA conditions but increased by an IL-23 inhibitor αIL-23p19. Adoptively transferred CD39+CD9+ IMs suppress neutrophil extracellular trap formation (NETosis), a representative phenotype of NDA, and also Th17 cell activation and neutrophilic inflammation. CD39+CD9+ IMs first attach to neutrophils in a CD9-dependent manner, and then remove ATP near neutrophils that contribute to NETosis in a CD39-dependent manner. Transcriptomic data from asthmatic patients finally show decreased CD39+CD9+ IMs in severe asthma than mild/moderate asthma. Our results suggest that CD39+CD9+ IMs function as a potent negative regulator of neutrophilic inflammation by suppressing NETosis in the IL-23-Th17 axis and can thus serve as a potential therapeutic target for IL-23-Th17-mediated neutrophilic asthma.

The mode of action of IL-23 in experimental inflammatory arthritic pain and disease.

OBJECTIVES: We have previously reported using gene-deficient mice that the interleukin (IL)-23p19 subunit is required for the development of innate immune-driven arthritic pain and disease. We aimed to explore here, using a number of in vivo approaches, how the IL-23p19 subunit can mechanistically control arthritic pain and disease in a T- and B- lymphocyte-independent manner. METHODS: We used the zymosan-induced arthritis (ZIA) model in wild-type and Il23p19-/- mice, by a radiation chimera approach, and by single cell RNAseq and qPCR analyses, to identify the IL23p19-expressing and IL-23-responding cell type(s) in the inflamed joints. This model was also utilized to investigate the efficacy of IL-23p19 subunit blockade with a neutralizing monoclonal antibody (mAb). A novel IL-23-driven arthritis model was established, allowing the identification of putative downstream mediators of IL-23 in the control of pain and disease. Pain and arthritis were assessed by relative static weight distribution and histology, respectively. RESULTS: We present evidence that (i) IL-23p19+ non-bone marrow-derived macrophages are required for the development of ZIA pain and disease, (ii) prophylactic and therapeutic blockade of the IL-23p19 subunit ameliorate ZIA pain and disease and (iii) systemically administered IL-23 can induce arthritic pain and disease in a manner dependent on TNF, GM-CSF, CCL17 and cyclooxygenase activity, but independently of lymphocytes, CGRP, NGF and substance P. CONCLUSIONS: The data presented should aid IL-23 targeting both in the choice of inflammatory disease to be treated and the design of clinical trials.

An IL-23-STAT4 pathway is required for the proinflammatory function of classical dendritic cells during CNS inflammation.

Although many cytokine pathways are important for dendritic cell (DC) development, it is less clear what cytokine signals promote the function of mature dendritic cells. The signal transducer and activator of transcription 4 (STAT4) promotes protective immunity and autoimmunity downstream of proinflammatory cytokines including IL-12 and IL-23. In experimental autoimmune encephalomyelitis (EAE), an animal model of multiple sclerosis (MS), Stat4-/- mice are resistant to the development of inflammation and paralysis. To define whether STAT4 is required for intrinsic signaling in mature DC function, we used conditional mutant mice in the EAE model. Deficiency of STAT4 in CD11c-expressing cells resulted in decreased T cell priming and inflammation in the central nervous system. EAE susceptibility was recovered following adoptive transfer of wild-type bone marrow-derived DCs to mice with STAT4-deficient DCs, but not adoptive transfer of STAT4- or IL-23R-deficient DCs. Single-cell RNA-sequencing (RNA-seq) identified STAT4-dependent genes in DC subsets that paralleled a signature in MS patient DCs. Together, these data define an IL-23-STAT4 pathway in DCs that is key to DC function during inflammatory disease.

Anti-IL23/12 agents and JAK inhibitors for inflammatory bowel disease.

IBD (inflammatory bowel disease) is a chronic inflammatory disease of the gastrointestinal tract with increasing incidence worldwide. Multiple factors, such as genetic background, environmental and luminal factors, and mucosal immune dysregulation, have been implicated in the cause of IBD, although the cause of the disease remains unknown. IL-12 and IL-23 and their downstream signaling pathways participate in the pathogenesis of inflammatory bowel disease. Early and aggressive treatment with biologic therapies or novel small molecules is needed to decrease complications and the need for hospitalization and surgery. The landscape of inflammatory bowel disease (IBD) treatment has tremendously improved with the development of biologics and small molecule drugs. Several novel biologics and small molecule drugs targeting IL-12 and IL-23 and their downstream targets have shown positive efficacy and safety data in clinical trials, and several drugs have been approved for the treatment of IBD. In the future, numerous potential emerging therapeutic options for IBD treatment are believed to come to the fore, achieving disease cure.

Risk of neutropenia in psoriasis patients prescribed anti-IL-23 antibody in comparison with anti-IL-17 antibody or adalimumab based on real-world data from the MID-NET® in Japan.

BACKGROUND: To evaluate the risk of neutropenia during treatment with anti-IL-23 antibodies in patients with psoriasis. METHOD: We conducted an observational study with cohort design using MID-NET® in Japan. We identified patients with psoriasis who were newly prescribed anti-IL-23 antibodies, anti-IL-17-antibodies, adalimumab, or apremilast between January 1, 2009, and March 31, 2021. We estimated the adjusted hazard ratio (aHR) of anti-IL-23 antibodies compared to that of anti-IL-17 antibodies, adalimumab, or apremilast, for the risk of grade 2 (neutrophil count < 1,500/µL) or grade 3 (neutrophil count < 1,000/µL) neutropenia. RESULTS: Overall, 287 patients on anti-IL-23 antibodies, 189 patients on anti-IL-17 antibodies, 293 patients on adalimumab, and 540 patients on apremilast were included. Compared with anti-IL-17 antibodies, the aHR (95% confidence interval (CI)) of anti-IL-23 antibodies was 0.83 (0.27-2.51) for grade 2 and 0.40 (0.02-7.60) for grade 3 neutropenia; that when compared with adalimumab was 0.76 (0.28-2.06) for grade 2 but was not calculated for grade 3 as no cases were found; and that compared with apremilast was 3.88 (0.62-24.48) for grade 2 and 0.43 (0.02-11.63) for grade 3 neutropenia. CONCLUSION: No clear increase in the risk of neutropenia with anti-IL-23 antibodies was observed.

Sequencing of Targeted Therapy in Psoriasis: Does it Matter?

With the continued development of biologics for the treatment of psoriasis, some patients have achieved optimal control, but a recommended biologic sequence if a biologic fails to initially improve the skin, termed primary nonresponse, or loses efficacy after initial improvement, termed secondary nonresponse, is still lacking. Primary and secondary nonresponse can occur with any class of biologics, and the type of nonresponse can drive the choice of whether to switch within a biologic class or to a different biologic class. The choice of biologic can also be challenging when managing psoriasis and concomitant psoriatic arthritis, as treatment differs on the basis of the severity of both diseases and further classification of axial and peripheral joint involvement. When choosing a biologic, each patient's comorbidities and preferences are also taken into account to provide the optimal therapy. With this lack of an established biologic sequence after biologic failure, the objective of our review is to define a therapy sequence for the tumor necrosis factor (TNF), interleukin-17 (IL-17), and interleukin-23 (IL-23) inhibitor classes in the treatment of psoriasis and psoriatic arthritis. Our proposed biologic sequence was derived through an analysis of the efficacy of each biologic class, primary and secondary nonresponse rates from clinical trials, and clinical experience with expert opinion.

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.

Prevalence of antiphospholipid autoantibodies associated with biologics treatment for psoriasis.

Psoriasis is a chronic inflammatory disease that sometimes necessitates therapeutic intervention with biologics. Autoantibody production during treatment with tumor necrosis factor (TNF) inhibitors is a recognized phenomenon, however, the production of autoantibodies associated with antiphospholipid syndrome (APS) has not been comprehensively evaluated in patients with psoriasis. This study was conducted to assess the prevalence of APS-associated autoantibodies in patients with psoriasis treated with different biologics and to investigate the potential associations between autoantibody production and clinical or serological parameters. Patients with psoriasis undergoing biologics treatments were enrolled in this study, and were categorized based on the type of biologics administered, TNF, interleukin (IL)-17, or IL-23 inhibitors. Clinical and serological data were collected and analyzed in conjunction with data on APS autoantibodies. TNF inhibitors were associated with a higher frequency of APS autoantibodies compared to IL-17 and IL-23 inhibitors. Notably, the presence of APS autoantibodies correlated with concurrent arthritis and higher disease severity at treatment initiation in patients treated with TNF inhibitors. Elevated Psoriasis Area and Severity Index scores and anti-nuclear antibody titers higher than × 320 were predictors of APS autoantibody production. Despite the higher autoantibody rates, clinical symptoms of APS were absent in these patients. This study provides the first comprehensive evidence of an increased frequency of APS autoantibodies associated with TNF inhibitor treatment in patients with psoriasis. The observed association between APS autoantibody positivity and TNF inhibitor treatment or clinical parameters suggests a potential immunomodulatory interplay between autoimmunity and inflammation in the pathogenesis of psoriasis.

Targeting cytokines in psoriatic arthritis.

Psoriatic arthritis (PsA) is part of the psoriatic disease spectrum and is characterized by a chronic inflammatory process that affects entheses, tendons and joints. Cytokines produced by immune and non-immune cells play a central role in the pathogenesis of PsA by orchestrating key aspects of the inflammatory response. Pro-inflammatory cytokines such as TNF, IL-23 and IL-17 have been shown to regulate the initiation and progression of PsA, ultimately leading to the destruction of the architecture of the local tissues such as soft tissue, cartilage and bone. The important role of cytokines in PsA has been underscored by the clinical success of antibodies that neutralize their function. In addition to biologic agents targeting individual pro-inflammatory cytokines, signaling inhibitors that block multiple cytokines simultaneously such as JAK inhibitors have been approved for PsA therapy. In this review, we will focus on our current understanding of the role of cytokines in the disease process of PsA and discuss potential new treatment options based on modulation of cytokine function.

Renal IL-23-Dependent Type 3 Innate Lymphoid Cells Link Crystal-induced Intrarenal Inflammasome Activation with Kidney Fibrosis.

Chronic inflammasome activation in mononuclear phagocytes (MNPs) promotes fibrosis in various tissues, including the kidney. The cellular and molecular links between the inflammasome and fibrosis are unclear. To address this question, we fed mice lacking various immunological mediators an adenine-enriched diet, which causes crystal precipitation in renal tubules, crystal-induced inflammasome activation, and renal fibrosis. We found that kidney fibrosis depended on an intrarenal inflammasome-dependent type 3 immune response driven by its signature transcription factor Rorc (retinoic acid receptor-related orphan receptor C gene), which was partially carried out by type 3 innate lymphoid cells (ILC3s). The role of ILCs in the kidney is less well known than in other organs, especially that of ILC3. In this article, we describe that depletion of ILCs or genetic deficiency for Rorc attenuated kidney inflammation and fibrosis. Among the inflammasome-derived cytokines, only IL-1ß expanded ILC3 and promoted fibrosis, whereas IL-18 caused differentiation of NKp46+ ILC3. Deficiency of the type 3 maintenance cytokine, IL-23, was more protective than IL-1ß inhibition, which may be explained by the downregulation of the IL-1R, but not of the IL-23R, by ILC3 early in the disease, allowing persistent sensing of IL-23. Mechanistically, ILC3s colocalized with renal MNPs in vivo as shown by multiepitope-ligand cartography. Cell culture experiments indicated that renal ILC3s caused renal MNPs to increase TGF-ß production that stimulated fibroblasts to produce collagen. We conclude that ILC3s link inflammasome activation with kidney inflammation and fibrosis and are regulated by IL-1ß and IL-23.

Illuminating the impact of γδ T cells in man and mice in spondylarthritides.

Spondylarthritides (SpA) are a group of autoinflammatory diseases affecting the spine, peripheral joints, and entheses, including axial spondyloarthritis (axSpA) and psoriatic arthritis. AxSpA has a multifactorial etiology that involves genetic predispositions, such as HLA-B27 and IL-23R. Although HLA-B27 is strongly associated with axSpA, its role remains unclear. GWAS studies have demonstrated that genetic polymorphisms related to the IL-23 pathway occur throughout the spectrum of SpA, including but not limited to axSpA and PsA. IL-23 promotes the production of IL-17, which drives inflammation and tissue damage. This pathway contributes not only to peripheral enthesitis but also to spinal inflammation. γδ T cells in axSpA express IL-23R and RORγt, crucial for their activation, although specific pathogenic cells and factors remain elusive. Despite drug efficacy in PsA, IL-23R inhibition is ineffective in axSpA. Murine models provide valuable insights into the intricate cellular and molecular interactions that contribute to the development and progression of SpA. Those models are useful tools to elucidate the dynamics of γδ T cell involvement, offering insights into disease mechanisms and potential therapeutic targets. This review aims to illuminate the complex interplay between IL-23 and γδ T cells in SpA pathogenesis, emphasizing their roles in chronic inflammation, tissue damage, and disease heterogeneity.

CTLA-4-expressing ILC3s restrain interleukin-23-mediated inflammation.

Interleukin (IL-)23 is a major mediator and therapeutic target in chronic inflammatory diseases that also elicits tissue protection in the intestine at homeostasis or following acute infection1-4. However, the mechanisms that shape these beneficial versus pathological outcomes remain poorly understood. To address this gap in knowledge, we performed single-cell RNA sequencing on all IL-23 receptor-expressing cells in the intestine and their acute response to IL-23, revealing a dominance of T cells and group 3 innate lymphoid cells (ILC3s). Unexpectedly, we identified potent upregulation of the immunoregulatory checkpoint molecule cytotoxic T-lymphocyte-associated antigen-4 (CTLA-4) on ILC3s. This pathway was activated by gut microbes and IL-23 in a FOXO1- and STAT3-dependent manner. Mice lacking CTLA-4 on ILC3s exhibited reduced regulatory T cells, elevated inflammatory T cells and more-severe intestinal inflammation. IL-23 induction of CTLA-4+ ILC3s was necessary and sufficient to reduce co-stimulatory molecules and increase PD-L1 bioavailability on intestinal myeloid cells. Finally, human ILC3s upregulated CTLA-4 in response to IL-23 or gut inflammation and correlated with immunoregulation in inflammatory bowel disease. These results reveal ILC3-intrinsic CTLA-4 as an essential checkpoint that restrains the pathological outcomes of IL-23, suggesting that disruption of these lymphocytes, which occurs in inflammatory bowel disease5-7, contributes to chronic inflammation.

Differential detection of chicken heterodimeric cytokines, interleukin 12 and 23 using their subunit-specific mouse monoclonal antibodies.

Interleukin-23 (IL-23) is a recently identified member of the IL-12 family of heterodimeric cytokines that play a critical role in regulating T helper cell function. IL-12 and IL-23 share a common p40 subunit, but differ in their p35 and p19 subunits, respectively. This difference in subunit composition results in distinct signaling pathways and biological functions for IL-12 and IL-23. Here, we report the functional characterization and immunomodulatory properties of chicken IL-12 and IL-23 using the panels of newly developed mouse anti-IL-12p40, IL-12p35-α and IL-23p19 monoclonal antibodies (mAbs). Western blot and indirect ELISA analysis demonstrated that the anti-chicken IL-12p40 mAbs (chIL-12p40; #10G10F4 and #10D8G2) bound to both recombinant proteins (IL-12 and IL-23), the anti-chicken IL-12p35 mAb (chIL-12p35; #2F1) specifically recognized recombinant IL-12, and the anti-chicken IL-23p19 mAb (chIL-23p19; #15A3) exhibited specificity for recombinant IL-23, without any cross-reactivity. Two ELISAs detecting specific chicken IL-12 (#10G10F4 and #2F1) or IL-23 (#10D8G2 and #15A3) were developed using newly developed mAb combinations, #10G10F4/ #2F1 and #10D8G2/#15A3 for IL-12 and IL-23, respectively, identified through a pairing assay. The levels of IL-12 and IL-23 in Resiquimod-848 stimulated-HD11 chicken macrophage cells were monitored over time using antigen-capture sandwich ELISA developed in this study. Furthermore, the levels of chicken IL-12 and IL-23 in the circulation of Eimeria maxima (E. maxima) and Eimeria tenella (E. tenella)-infected chickens were determined. Notably, the anti-chIL-12p40 mAbs (#10G10F4 and #10D8G2) neutralized the function of both chIL-12 and chIL-23 proteins, which share the p40 subunit, while the anti-chIL-23p19 mAb (#15A3) specifically neutralized chIL-23 protein in HD11 cells in vitro. The anti-chIL-12p35 mAb (#2F1), which is specific to the p35 subunit of IL-12, showed a partial neutralizing effect on chIL-12 protein. Collectively, our study validates the specificity and significance of 2 newly developed antigen-capture immunoassays for chIL-12 and chIL-23 which will expand our understanding of the functional characteristics of IL-12 and IL-23 and their association in normal and diseased chickens. These mAbs for each subunit, anti-chIL-12p35, anti-chIL-12p40 and anti-chIL-23p19, will serve as valuable immune reagents to elucidate host immune responses against disease pathogenesis in both fundamental and applied studies of avian species.

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.

Myelin-reactive B cells exacerbate CD4+ T cell-driven CNS autoimmunity in an IL-23-dependent manner.

B cells and T cells collaborate in multiple sclerosis (MS) pathogenesis. IgH[MOG] mice possess a B cell repertoire skewed to recognize myelin oligodendrocyte glycoprotein (MOG). Here, we show that upon immunization with the T cell-obligate autoantigen, MOG[35-55], IgH[MOG] mice develop rapid and exacerbated experimental autoimmune encephalomyelitis (EAE) relative to wildtype (WT) counterparts, characterized by aggregation of T and B cells in the IgH[MOG] meninges and by CD4+ T helper 17 (Th17) cells in the CNS. Production of the Th17 maintenance factor IL-23 is observed from IgH[MOG] CNS-infiltrating and meningeal B cells, and in vivo blockade of IL-23p19 attenuates disease severity in IgH[MOG] mice. In the CNS parenchyma and dura mater of IgH[MOG] mice, we observe an increased frequency of CD4+PD-1+CXCR5- T cells that share numerous characteristics with the recently described T peripheral helper (Tph) cell subset. Further, CNS-infiltrating B and Tph cells from IgH[MOG] mice show increased reactive oxygen species (ROS) production. Meningeal inflammation, Tph-like cell accumulation in the CNS and B/Tph cell production of ROS were all reduced upon p19 blockade. Altogether, MOG-specific B cells promote autoimmune inflammation of the CNS parenchyma and meninges in an IL-23-dependent manner.