This study represents the first description of the cloning of chicken IL-23p19 (ChIL-23α) and the function of the IL-23 complex in birds. Multiple alignment of ChIL-23α with other known IL-23α amino acid sequences revealed regions of amino acid conservation. The homologies of ChIL-23α, IL-12p35, and similar mammalian subunits ranged between 26% and 42%. ChIL-23α consisted of four exons and three introns; similar to those in humans and mice, and limited conservation of synteny between the human and chicken genomes was observed. Using bioinformatics tools, we identified the NF-κB, C/EBPα-β, c-Jun, c-Rel, AP-1, GATA-1, and ER promoter sites in ChIL-23α. Moreover, IL-23α mRNA was more highly expressed than IL-12p40 and IL-12p35 mRNA in several organs of chickens infected with Salmonella. In addition, ChIL-23 complex are associated with IL-23R, IL-12Rβ1 receptors; activate the JAK2/TYK2, STAT1/3, SOCS1 genes, and induced proinflammatory cytokines in immune cells. Collectively, these results indicate that ChIL-23 is a member of the IL-12 family, has proinflammatory properties related to IL-23R and IL-12Rβ1 receptor expression, and activates the JAK/STAT signaling pathway that results in the interaction of ChIL-23α with ChIL-12p40 to form the novel ChIL-23 complex. Our results provide novel insights into the regulation of immunity, inflammation, and immunopathology.

Previous analyses of pooled DISCOVER-1 and DISCOVER-2 data through Week 24 showed significantly higher rates of dactylitis resolution in patients treated with guselkumab compared with placebo. Here, we investigate associations between dactylitis resolution and other outcomes through 1 year.

To assess long-term efficacy and safety of guselkumab, an interleukin-23 p19 subunit (IL-23p19) inhibitor, in patients with active psoriatic arthritis (PsA) from the phase III DISCOVER-2 trial.

This paper reports the cloning and sequencing of interleukin (IL)-23 p19 subunit for the first time within a non-mammalian species, the zebrafish (Danio rerio), which was discovered using a synteny approach. In addition, amino acid sequences were for IL-23 p19 subunits were also predicted from the stickleback, Fugu and Tetraodon genomes and included in this investigation. The zebrafish IL-23 p19 cDNA consisted of a 66bp 5' UTR, a 249bp 3' UTR and a single open reading frame of 567bp giving a predicted 188 aa IL-23 p19 molecule. Multiple alignment of zebrafish IL-23 p19, with other known IL-23 p19 and IL-12 p35 amino acid sequences revealed areas of amino acid conservation, such as the presence of four predicted α-helixes, cysteines important for disulphide bond formation and the conservation of a tryptophan known to interact with the receptor. Amino acid homologies and phylogenetic analysis confirmed the relationship of the fish IL-23 p19 subunits with their mammalian homologues. All the teleost fish IL-23 p19 subunits were found to have 4 exons and 3 introns similar to that of human and mouse IL-23 p19 and a limited degree of synteny was found between the organisms for the regions containing the IL-23 p19 genes with only PAB-dependent poly(A)-specific ribonuclease subunit 2 (PAN2) and IL-23 p19 found in the same order on human chromosome 12 and all the fish genomes looked at. Lastly using real-time PCR, constitutive expression of IL-12 p40 and IL-23 p19 was observed in the kidney, liver, gut and muscle with IL-12 p40 expression higher than IL-23 p19. As soon as an hour after stimulation with LPS, there was an increase of IL-23 p19 in zebrafish leukocytes and an increase of IL-1β, IL-12 p40 and IL-23 p19 expression was found after infection of zebrafish for 1 or 6 days with Mycobaterium marinum strain E11.

Th17 cells have been reported to produce proinflammatory cytokines like Interleukin-17, IL-22, and regarded as important players in various inflammatory diseases. One of the IL-12 cytokine family cytokines, IL-23, composed of p19 and p40 subunit, is known for its potential to promote Th17 development and IL-17 producing, and the IL-23/IL-17 pathway is considered to be potential therapeutic target for autoimmune inflammation responses. Knockout mice deficient in either IL-23 or IL-17 related genes can suppress the allergic responses. Several IL-23 or IL-17 neutralizing agents are being evaluated in vitro or in vivo to disrupt the IL-23/IL-17 axis. Herein, we report that prokaryotically expressed soluble IL-23 receptor cytokine-binding homology region as an endogenous extracellular receptor analogue could be a natural antagonist against IL-23/IL-17 axis. We provide evidence that IL23R-CHR can bind to IL-23 in a dose-dependent manner in vitro, and block IL-23 signal by IL23R-CHR reducing the RORγt expression, which in turn lowers the expression of IL-17/IL-22, thus protecting naive CD4+ T cells against Th17 development. Together, this study indicates the importance of IL-23 pathway in Th17 development and the negative regulation of Th17 development by IL23R-CHR, and highlights the important roles of the soluble receptor extracellular region in the therapeutic strategy of neutralizing IL-23.

The heterodimeric cytokine interleukin (IL) 23 comprises the IL12-shared p40 subunit and an IL23-specific subunit, p19. Together with IL12 and IL27, IL23 sits at the apex of the regulatory mechanisms shaping adaptive immune responses. IL23, together with IL17, plays an important role in the development of chronic inflammation and autoimmune inflammatory diseases. In this context, we generated monovalent antihuman IL23 variable heavy chain domain of llama heavy chain antibody (VHH) domains (Nanobodies®) with low nanomolar affinity for human interleukin (hIL) 23. The crystal structure of a quaternary complex assembling hIL23 and several nanobodies against p19 and p40 subunits allowed identification of distinct epitopes and enabled rational design of a multivalent IL23-specific blocking nanobody. Taking advantage of the ease of nanobody formatting, multivalent IL23 nanobodies were assembled with properly designed linkers flanking an antihuman serum albumin nanobody, with improved hIL23 neutralization capacity in vitro and in vivo, as compared to the monovalent nanobodies. These constructs with long exposure time are excellent candidates for further developments targeting Crohn's disease, rheumatoid arthritis, and psoriasis.

Engineered combinatorial libraries derived from small protein scaffolds represent a powerful tool for generating novel binders with high affinity, required specificity and designed inhibitory function. This work was aimed to generate a collection of recombinant binders of human interleukin-23 receptor (IL-23R), which is a key element of proinflammatory IL-23-mediated signaling. A library of variants derived from the three-helix bundle scaffold of the albumin-binding domain (ABD) of streptococcal protein G and ribosome display were used to select for high-affinity binders of recombinant extracellular IL-23R. A collection of 34 IL-23R-binding proteins (called REX binders), corresponding to 18 different sequence variants, was used to identify a group of ligands that inhibited binding of the recombinant p19 subunit of IL-23, or the biologically active human IL-23 cytokine, to the recombinant IL-23R or soluble IL-23R-IgG chimera. The strongest competitors for IL-23R binding in ELISA were confirmed to recognize human IL-23R-IgG in surface plasmon resonance experiments, estimating the binding affinity in the sub- to nanomolar range. We further demonstrated that several REX variants bind to human leukemic cell lines K-562, THP-1 and Jurkat, and this binding correlated with IL-23R cell-surface expression. The REX125, REX009 and REX128 variants competed with the p19 protein for binding to THP-1 cells. Moreover, the presence of REX125, REX009 and REX115 variants significantly inhibited the IL-23-driven expansion of IL-17-producing primary human CD4(+) T-cells. Thus, we conclude that unique IL-23R antagonists derived from the ABD scaffold were generated that might be useful in designing novel anti-inflammatory biologicals.

Interleukin-23 (IL-23) is a heterodimeric cytokine that consists of p19, a novel subunit, and p40, which is shared by IL-12. IL-23 has been demonstrated to play an important role in autoimmunity and tumor growth. However, the role of IL-23 in ocular neovascularization (NV) diseases remains unclear. In this study, we explored the role of IL-23 in the processing of retinal and choroidal neovascularization (RNV and CNV). We found a significantly higher expression of IL-23 in the retinas with oxygen-induced retinopathy (OIR), and after neutralizing IL-23, the mRNA and protein levels of the angiogenic factors vascular endothelial growth factor receptor (VEGFR)1/FLT-1, VEGFR2/FLK-1, placental growth factor (PIGF), endothelial-specific receptor tyrosine kinase (Tie2), inducible nitric-oxide synthase (iNOS), matrix metalloproteinase (MMP) 2 and MMP9 were significantly down regulated, while the opposite trend was found for the anti-angiogenic molecules chemokine (C-X-C motif) ligand (CXCL) 9 and CXCL10. IL-23 blockade caused less NV in both the RNV and CNV mouse models. In addition, our in vitro assay showed that IL-23 alone is able to increase the ability of endothelial cells to form tubes. Our findings suggest that targeting IL-23 could be a potential therapy for RNV and CNV diseases.

Asthma is a heterogeneous chronic inflammatory disorder of the airways with a complex etiology, which involves a variety of cells and cellular components. Therefore, the aim of the study was to investigate the effects and mechanisms of antagonistic peptides that specifically bind to the first and second extracellular loops of CCR5 (GH and HY peptides, respectively) and anti-interleukin-23 subunit p19 (anti-IL-23p19) in the airway and thereby mediate inflammation and the IL-23/T helper 17 (Th17) cell pathway in asthmatic mice. An experimental asthma model using BALB/c mice was induced by ovalbumin (OVA) and treated with peptides that are antagonistic to CCR5 or with anti-IL-23p19. The extents of the asthmatic inflammation and mucus production were assessed. In addition, bronchoalveolar lavage fluid (BALF) was collected, the cells were counted, and the IL-4 level was detected by ELISA. The IL-23/Th17 pathway-related protein and mRNA levels in the lung tissues were measured, and the positive production rates of Th17 cells in the thymus, spleen, and peripheral blood were detected. The groups treated with one of the two peptides and/or anti-IL-23p19 showed significant reductions in allergic inflammation and mucus secretion; decreased expression levels of IL-23p19, IL-23R, IL-17A and lactoferrin (LTF); and reduced proportions of Th17 cells in the thymus, spleen, and peripheral blood. Specifically, among the four treatment groups, the anti-IL-23p19 with HY peptide group exhibited the lowest positive production rate of Th17 cells. Our data also showed a significant and positive correlation between CCR5 and IL-23p19 protein expression. These findings suggest that the administration of peptides antagonistic to CCR5 and/or anti-IL-23p19 can reduce airway inflammation in asthmatic mice, most likely through inhibition of the IL-23/Th17 signaling pathway, and the HY peptide can alleviate inflammation not only through the IL-23/Th17 pathway but also through other mechanisms that result in the regulation of inflammation.

Tildrakizumab is a humanized monoclonal antibody that binds selectively the p19 subunit of interleukin-23. It is approved for treatment of moderate-severe chronic plaque psoriasis.

Mirikizumab, a monoclonal antibody targeting the interleukin-23 p19 subunit, was effective in a Phase 2 study (NCT02589665) of moderately-to-severely active ulcerative colitis (UC). We studied mirikizumab's impact on health-related quality of life (HRQoL).

Mirikizumab, a monoclonal antibody targeting the p19 subunit of interleukin (IL)-23, demonstrated efficacy and was well-tolerated in a phase 2 randomized clinical trial in patients with moderate-to-severe ulcerative colitis (UC) (NCT02589665). We explored gene expression changes in colonic tissue from study patients and their association with clinical outcomes.

Psoriasis is a chronic inflammatory skin condition that impacts quality of life and requires long-term treatment and effective symptom management. Interleukin-23 (IL-23) has emerged as a key player in the pathogenesis of psoriasis and tildrakizumab and guselkumab are both immunomodulatory agents that inhibit the p19 subunit of IL-23. In its pivotal Phase III trial, tildrakizumab demonstrated greater efficacy than etanercept in moderate-to-severe psoriasis. However, there are no head-to-head trials comparing tildrakizumab with guselkumab.

A newly described heterodimeric cytokine, interleukin-23 (IL-23) is emerging as a key player in both the innate and the adaptive T helper (Th)17 driven immune response as well as an initiator of several autoimmune diseases. The rate-limiting element of IL-23 production is believed to be driven by expression of the unique p19 subunit encoded by IL23A. We set out to perform comprehensive DNA sequencing of this previously under-studied gene in 96 individuals from two evolutionary distinct human population groups, Southern African Bantu and European. We observed a total of 33 different DNA variants within these two groups, 22 (67%) of which are currently not reported in any available database. We further demonstrate both inter-population and intra-species sequence conservation within the coding and known regulatory regions of IL23A, supporting a critical physiological role for IL-23. We conclude that IL23A may have undergone positive selection pressure directed towards conservation, suggesting that functional genetic variants within IL23A will have a significant impact on the host immune response.

Risankizumab, a humanized monoclonal antibody that targets interleukin-23 p19 subunit, was developed for the treatment of psoriasis. This work characterizes risankizumab pharmacokinetics in Japanese and Chinese healthy subjects compared with white healthy subjects and in Japanese patients with moderate to severe plaque psoriasis, generalized pustular psoriasis, or erythrodermic psoriasis. A phase 1, single-dose study evaluated risankizumab pharmacokinetics and safety/tolerability in healthy white (18 and 300 mg subcutaneous [SC]), Japanese (18, 90, and 300 mg SC and 200, 600, and 1200 mg intravenous [IV]), and Chinese (18, 90, and 300 mg SC) subjects; pharmacokinetic data were analyzed using noncompartmental methods. Risankizumab pharmacokinetic data from phase 2/3 studies in Japanese patients with plaque psoriasis, generalized pustular psoriasis, or erythrodermic psoriasis following multiple SC doses of 75 mg or 150 mg were analyzed using a population pharmacokinetic approach along with data from the phase 1 and global phase 1 to 3 studies. Risankizumab plasma exposures (peak plasma concentration and area under the concentration-time curve) were approximately dose-proportional across 18- to 300-mg SC or 200- to 1200-mg IV doses. Risankizumab terminal elimination half-life (harmonic mean 27-34 days) was comparable across doses and ethnicities. Risankizumab exposures were approximately 20% to 30% higher in Japanese and Chinese healthy subjects compared with white healthy subjects or in Japanese patients compared with non-Japanese patients. After accounting for body-weight differences, risankizumab exposures were comparable across ethnicities. Overall, there was no ethnic impact on risankizumab pharmacokinetics, and the small difference in exposure due to body weight has no clinical relevance.

CD137, a potent costimulatory receptor for CD8+ T cells, is expressed in various non-T cells, but little is known about its regulatory functions in these cells. In this study, we show that CD137 signaling, specifically in intestinal CD11b-CD103+ dendritic cells (DCs), restricts acute colitis progression. Mechanistically, CD137 engagement activates TAK1 and subsequently stimulates the AMPK-PGC-1α axis to enhance expression of the Aldh1a2 gene encoding the retinoic acid (RA) metabolizing enzyme RALDH2. RA can act on CD11b+CD103- DCs and induce SOCS3 expression, which, in turn, suppresses p38MAPK activation and interleukin-23 (IL-23) production. Administration of RA in DC-specific CD137-/- mice represses IL-23-producing CD11b+CD103- DCs and TH17 cells, indicating that RA is a major inhibitory effector molecule against intestinal CD11b+CD103- DCs. Additionally, the therapeutic effect of the anti-CD137 antibody is abrogated in DC-specific CD137-/- mice. Taken together, our results define a mechanism of paracrine immunoregulation operating between adjacent DC subsets in the intestine.