The role of IL-23 receptor signaling in inflammation-mediated erosive autoimmune arthritis and bone remodeling

Weighted Gene Co-expression Network Analysis of the Inflammatory Wnt Signaling Reveals Biomarkers Related to Bone Formation

Background and aim Osteocytes regulate bone metabolism and balance through various mechanisms, including the Wnt (Wingless-related integration site signal transduction) signaling pathway. Weighted gene co-expression network analysis (WGCNA) is a computational method to identify functionally related genes based on expression patterns, especially in the Wnt-beta-catenin and osteo-regenerative pathways. This study aims to analyze gene modules of the Wnt signaling pathway from WGCNA analysis. Methods The study used a microarray dataset from the GEO (GSE228306) to analyze differential gene expression in human primary monocytes. The study standardized datasets using Robust Multi-Array Average (RMA) expression measure and Integrated Differential Expression and Pathway (IDEP) analysis tool, building a co-expression network for group-specific component (GC) genes. Results The study uses WGCNA to identify co-expression modules with dysregulated mRNAs, revealing enrichment in Wnt-associated pathways and top hub-enriched genes like colony-stimulating factor 3 (CSF3), interleukin-6 (IL-6), IL-23 subunit alpha (IL23A), suppressor of cytokine signaling 1 (SOCS1), and C-C motif chemokine ligand 19 (CCL19). Conclusion WGCNA analysis of the Wnt signaling pathway will involve functional annotation, network visualization, validation, integration with other omics data, and addressing method limitations for better understanding.

Osteoarthritis versus psoriasis arthritis: Physiopathology, cellular signaling, and therapeutic strategies

Osteoarthritis and psoriasis arthritis are two degenerative forms of arthritis that share similar yet also different manifestations at the histological, cellular, and clinical levels. Rheumatologists have marked them as two entirely distinct arthropathies. Given recent discoveries in disease initiation and progression, potential mechanisms, cellular signaling pathways, and ongoing clinical therapeutics, there are now more opportunities for discovering osteoarthritis drugs. This review summarized the osteoarthritis and psoriasis arthritis signaling pathways, crosstalk between BMP, WNT, TGF-β, VEGF, TLR, and FGF signaling pathways, biomarkers, and anatomical pathologies. Through bench research, we demonstrated that regenerative medicine is a promising alternative for treating osteoarthritis by highlighting significant scientific discoveries on entheses, multiple signaling blockers, and novel molecules such as immunoglobulin new antigen receptors targeted for potential drug evaluation. Furthermore, we offered valuable therapeutic approaches with a multidisciplinary strategy to treat patients with osteoarthritis or psoriasis arthritis in the coming future in the clinic.

Biology and therapeutic potential of mesenchymal stem cell extracellular vesicles in axial spondyloarthritis

Axial spondyloarthritis (AxSpA) is a chronic, inflammatory, autoimmune disease that predominantly affects the joints of the spine, causes chronic pain, and, in advanced stages, may result in spinal fusion. Recent developments in understanding the immunomodulatory and tissue-differentiating properties of mesenchymal stem cell (MSC) therapy have raised the possibility of applying such treatment to AxSpA. The therapeutic effectiveness of MSCs has been shown in numerous studies spanning a range of diseases. Several studies have been conducted examining acellular therapy based on MSC secretome. Extracellular vesicles (EVs) generated by MSCs have been proven to reproduce the impact of MSCs on target cells. These EVs are associated with immunological regulation, tissue remodeling, and cellular homeostasis. EVs' biological effects rely on their cargo, with microRNAs (miRNAs) integrated into EVs playing a particularly important role in gene expression regulation. In this article, we will discuss the impact of MSCs and EVs generated by MSCs on target cells and how these may be used as unique treatment strategies for AxSpA.

Low rates of radiographic progression associated with clinical efficacy following up to 2 years of treatment with guselkumab: results from a phase 3, randomised, double-blind, placebo-controlled study of biologic-naïve patients with active psoriatic arthritis

OBJECTIVE

Evaluate relationship between radiographic progression and clinical outcomes in post hoc analyses of patients with psoriatic arthritis (PsA) receiving up to 2 years of guselkumab therapy in the phase 3, placebo-controlled, randomised trial, DISCOVER-2.

METHODS

Biologic-naïve adults with active PsA (≥5 swollen joints /≥5 tender joints ; C reactive protein ≥0.6 mg/dL) were randomised to guselkumab 100 mg every 4 weeks (Q4W); guselkumab 100 mg at week 0, week 4, then every 8 weeks (Q8W); or placebo→guselkumab 100 mg Q4W (week 24). Radiographs (hands/feet) at week 0, week 24, week 52 and week 100 were scored via PsA-modified van der Heijde-Sharp (vdH-S) methodology. In these post hoc analyses, mean changes in vdH-S scores were summarised according to achievement of American College of Rheumatology 20/50/70 response; low disease activity (LDA) defined by Disease Activity in Psoriatic Arthritis (DAPSA) ≤14 or Psoriatic ArthritiS Disease Activity Score (PASDAS) ≤3.2, or minimal/very low disease activity (MDA/VLDA); and normalised physical function (Health Assessment Questionnaire-Disability Index (HAQ-DI) ≤0.5). Response rates for achieving MDA/VLDA and each component were determined among patients with and without radiographic progression (change in total vdH-S score >0.5). No formal hypothesis testing was performed.

RESULTS

664 of 739 treated patients in DISCOVER-2 continued study treatment at week 52 and were included in these analyses. Mean changes in vdH-S scores from weeks 0 to 100 among all patients in the Q4W and Q8W groups were 1.7 and 1.5, respectively. Among all guselkumab-randomised patients, those who achieved ACR20/50/70, DAPSA LDA, PASDAS LDA, MDA, VLDA and HAQ-DI ≤0.5 (normalised physical function) had smaller mean changes in vdH-S scores than did non-responders at week 52 (0.2-1.2 vs 1.7-4.1) and week 100 (0.3-1.2 vs 2.0-4.6). Relative to patients with radiographic progression, those without progression were more likely to achieve the MDA criteria related to swollen and tender joint counts, patient-reported pain and global assessment, and normalised physical function through week 100.

CONCLUSION

In these post hoc analyses, the achievement of low levels of disease activity, including MDA, was associated with diminished rates of radiographic progression observed in patients receiving up to 2 years of guselkumab. Radiographic non-progressors were more likely to achieve patient-reported MDA criteria of minimal pain and normalised physical function compared with radiographic non-responders.

TRIAL REGISTRATION NUMBER

NCT03158285.

Identifying hub genes and miRNAs in Crohn’s disease by bioinformatics analysis

Introduction: Crohn’s disease (CD) is a disease that manifests mainly as chronic inflammation of the gastrointestinal tract, which is still not well understood in terms of its pathogenesis. The aim of this study was to use bioinformatics analysis to identify differentially expressed genes (DEGs) and miRNAs with diagnostic and therapeutic potential in CD.

Materials and methods: Three CD datasets (GSE179285, GSE102133, GSE75214) were downloaded from the Gene Expression Omnibus (GEO) database. DEGs between normal and CD tissues were identified using the GEO2R online tool. The Gene Ontology (GO) term and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway enrichment analyses of the DEGs were conducted using the clusterProfiler function in the R package. Protein-protein interaction network (PPI) analysis and visualization were performed with STRING and Cytoscape. Ten hub genes were identified using cytoHubba’s MCC algorithm and validated with datasets GSE6731 and GSE52746. Finally, the miRNA gene regulatory network was constructed by Cytoscape and NetworkAnalyst to predict potential microRNAs (miRNAs) associated with DEGs.

Results: A total of 97 DEGs were identified, consisting of 88 downregulated genes and 9 upregulated genes. The enriched functions and pathways of the DEGs include immune system process, response to stress, response to cytokine and extracellular region. KEGG pathway analysis indicates that the genes were significantly enriched in Cytokine-cytokine receptor interaction, IL-17 signaling pathway, Rheumatoid arthritis and TNF signaling pathway. In combination with the results of the protein-protein interaction (PPI) network and CytoHubba, 10 hub genes including IL1B, CXCL8, CXCL10, CXCL1, CXCL2, CXCL5, ICAM1, IL1RN, TIMP1 and MMP3 were selected. Based on the DEG-miRNAs network construction, 5 miRNAs including hsa-mir-21-5p, hsa-mir-93-5p, hsa-mir-98-5p, hsa-mir-1-3p and hsa-mir-335-5p were identified as potential critical miRNAs.

Conclusion: In conclusion, a total of 97 DEGs, 10 hub genes and 5 miRNAs that may be involved in the progression or occurrence of CD were identified in this study, which could be regarded as biomarkers of CD.

Clinical Overview of Arthritis with a Focus on Management Options and Preventive Lifestyle Measures for Its Control

ABSTRACT:

Arthritis is the spectrum of conditions that cause swelling and tenderness of one or more body joints with key symptoms of joint pain and stiffness. Its progression is closely tied to age. Although there are a number of arthritis types, such as, ankylosing, gout, joint infections, juvenile idiopathic, reactive and septic; the two most common types are osteoarthritis and rheumatoid arthritis. Osteoarthritis causes the articulating smooth cartilage that covers the ends of bones, where they form a joint, to breakdown. Rheumatoid arthritis is a disease in which the immune system attacks joints, beginning with the cartilaginous lining of the joints. The latter is considered a systemic disease, i.e. affecting many parts of the body, but the respiratory system is involved in 10 to 20 % of all mortality. Osteoarthritis is one of the leading causes of disability globally. Several preventive measures to control arthritis have been suggested, such as the use of analgesics, non-steroid anti-inflammatory drugs, moderate to vigorous physical activity and exercise, reducing sedentary hours, getting adequate sleep and maintaining a healthy body weight. Foods including, a Mediterranean diet rich in fruits and vegetables, fish oil, medicinal plants and microbiota are vital protective methods. The intake of vitamins such as A and C, minerals e.g., selenium and zinc; poly unsaturated and n-3 fatty acids is also a significant preventive measures.

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.

Complexity of enthesitis and new bone formation in ankylosing spondylitis: current understanding of the immunopathology and therapeutic approaches

Despite increasing availability of treatments for spondyloarthritis (SpA) including tumour necrosis factor (TNF) and interleukin-17 (IL-17) inhibitors, there is no established treatment that abates new bone formation (NBF) in ankylosing spondylitis (AS), a subset of SpA. Recent research on TNF has revealed the increased level of transmembrane TNF in the joint tissue of SpA patients compared to that of rheumatoid arthritis patients, which appears to facilitate TNF-driven osteo-proliferative changes in AS. In addition, there is considerable interest in the central role of IL-23/IL-17 axis in type 3 immunity and the therapeutic potential of blocking this axis to ameliorate enthesitis and NBF in AS. AS immunopathology involves a variety of immune cells, including both innate and adoptive immune cells, to orchestrate the immune response driving type 3 immunity. In response to external stimuli of inflammatory cytokines, local osteo-chondral progenitor cells activate intra-cellular anabolic molecules and signals involving hedgehog, bone morphogenetic proteins, receptor activator of nuclear factor kappa-B ligand, and Wnt pathways to promote NBF in AS. Here, we provide an overview of the current immunopathology and future directions for the treatment of enthesitis and NBF associated with AS.

IL-23 receptor deficiency results in lower bone mass via indirect regulation of bone formation

The IL-23 receptor (IL-23R) signaling pathway has pleiotropic effects on the differentiation of osteoclasts and osteoblasts, since it can inhibit or stimulate these processes via different pathways. However, the potential role of this pathway in the regulation of bone homeostasis remains elusive. Therefore, we studied the role of IL-23R signaling in physiological bone remodeling using IL-23R deficient mice. Using µCT, we demonstrate that 7-week-old IL-23R^−/− mice have similar bone mass as age matched littermate control mice. In contrast, 12-week-old IL-23R^−/− mice have significantly lower trabecular and cortical bone mass, shorter femurs and more fragile bones. At the age of 26 weeks, there were no differences in trabecular bone mass and femur length, but most of cortical bone mass parameters remain significantly lower in IL-23R^−/− mice. In vitro osteoclast differentiation and resorption capacity of 7- and 12-week-old IL-23R^−/− mice are similar to WT. However, serum levels of the bone formation marker, PINP, are significantly lower in 12-week-old IL-23R^−/− mice, but similar to WT at 7 and 26 weeks. Interestingly, Il23r gene expression was not detected in in vitro cultured osteoblasts, suggesting an indirect effect of IL-23R. In conclusion, IL-23R deficiency results in temporal and long-term changes in bone growth via regulation of bone formation.

Tissue Homeostasis and Inflammation

There is a growing interest in understanding tissue organization, homeostasis, and inflammation. However, despite an abundance of data, the organizing principles of tissue biology remain poorly defined. Here, we present a perspective on tissue organization based on the relationships between cell types and the functions that they perform. We provide a formal definition of tissue homeostasis as a collection of circuits that regulate specific variables within the tissue environment, and we describe how the functional organization of tissues allows for the maintenance of both tissue and systemic homeostasis. This leads to a natural definition of inflammation as a response to deviations from homeostasis that cannot be reversed by homeostatic mechanisms alone. We describe how inflammatory signals act on the same cellular functions involved in normal tissue organization and homeostasis in order to coordinate emergency responses to perturbations and ultimately return the system to a homeostatic state. Finally, we consider the hierarchy of homeostatic and inflammatory circuits and the implications for the development of inflammatory diseases.

Role of the IL23/IL17 Pathway in Crohn's Disease

Crohn's disease (CD) is a chronic relapsing disorder of the gastrointestinal tract and represents one of the main entities of inflammatory bowel disease (IBD). CD affects genetically susceptible patients that are influenced by environmental factors and the intestinal microbiome, which results in excessive activation of the mucosal immune system and aberrant cytokine responses. Various studies have implicated the pro-inflammatory cytokines IL17 and IL23 in the pathogenesis of CD. IL23 is a member of the IL12 family of cytokines and is able to enhance and affect the expansion of pathogenic T helper type 17 (Th17) cells through various mechanisms, including maintenance of Th17 signature genes, upregulation of effector genes or suppression of repressive factors. Moreover, IL17 and IL23 signaling is able to induce a cascade of pro-inflammatory molecules like TNF, IFNγ, IL22, lymphotoxin, IL1β and lipopolysaccharide (LPS). Here, IL17A and TNF are known to mediate signaling synergistically to drive expression of inflammatory genes. Recent advances in understanding the immunopathogenetic mechanisms underlying CD have led to the development of new biological therapies that selectively intervene and inhibit inflammatory processes caused by pro-inflammatory mediators like IL17 and IL23. Recently published data demonstrate that treatment with selective IL23 inhibitors lead to markedly high response rates in the cohort of CD patients that failed previous anti-TNF therapy. Macrophages are considered as a main source of IL23 in the intestine and are supposed to play a key role in the molecular crosstalk with T cell subsets and innate lymphoid cells in the gut. The following review focuses on mechanisms, pathways and specific therapies in Crohn's disease underlying the IL23/IL17 pathway.

Expression Profile of Osteoclasts Following the Stimulation With Interleukin-23 in Mice

Objectives

This study aims to analyze the expression profile of osteoclasts (OCs) following the stimulation with interleukin 23 (IL-23) in mice, which would imply the underlying effects of IL-23 on the function of OCs in inflammatory arthritis.

Materials and methods

Mature OCs were induced from bone marrow mononuclear cells of 5 male mice (age 6 weeks; weighing 18-20 g) in the presence of macrophage-colony stimulating factor (50 ng/mL) and receptor activator of nuclear factor kappa B ligand (30 ng/mL) in vitro. The Agilent SurePrint G3 Mouse GE V2.0 Microarray was used to analyze the gene expression profile of OCs stimulated with IL-23 (30 ng/mL) or vehicle. The four major IL-23-modulated genes were validated by quantitative real-time polymerase chain reaction (qPCR) analysis.

Results

The expression levels of 23 genes were up-regulated and 32 genes were down-regulated by IL-23 stimulation (fold change ≥1.5 and p value <0.05). Among them, there were 37 genes with assigned gene symbols. Gene ontology analysis showed that the IL-23-regulated messenger ribonucleic acids (mRNAs) were related to positive regulation of leukocyte chemotaxis, chemokine-mediated signaling pathway and C-X-C chemokine receptors binding. The pathway analysis showed that the IL-23-regulated mRNAs were related to chemokine signaling pathway and cytokine-cytokine receptor interaction. The significant up-regulation of chemokine (C-X-C motif) ligand 1 and chemokine (C-X-C motif) ligand 2 induced by IL-23 was confirmed by qPCR. In addition, there were 18 long non-coding RNAs that were regulated by IL-23, while their function needs to be confirmed in the future.

Conclusion

Expression levels of genes related to chemotaxis in OCs were up-regulated by IL-23 in mice, which imply that IL-23 may facilitate chemotaxis of OCs in inflammatory arthritis.

Identification of new susceptibility loci associated with rheumatoid arthritis

OBJECTIVES

The present study aimed to discover novel susceptibility loci associated with risk of rheumatoid arthritis (RA).

METHODS

We performed a new genome-wide association study (GWAS) in Chinese subjects (1027 RA cases and 2879 controls) and further conducted an expanded meta-analysis with previous GWAS summary data and replication studies. The functional roles of the associated loci were interrogated using publicly available databases. Dual-luciferase reporter and cytokine assay were also used for exploring variant function.

RESULTS

We identified five new susceptibility loci (IL12RB2, BOLL-PLCL1, CCR2, TCF7 and IQGAP1; p_meta <5.00E-08) with same effect direction in each study cohort. The sensitivity analyses showed that the genetic association of at least three loci was reliable and robust. All these lead variants are expression quantitative trait loci and overlapped with epigenetic marks in immune cells. Furthermore, genes within the five loci are genetically associated with risk of other autoimmune diseases, and genes within four loci are known functional players in autoimmunity, which supports the validity of our findings. The reporter assay showed that the risk allele of rs8030390 in IQGAP1 have significantly increased reporter activity in HEK293T cells. In addition, the cytokine assay found that the risk allele of rs244672 in TCF7 was most significantly associated with increased plasma IL-17A levels in healthy controls. Finally, identified likely causal genes in these loci significantly interacted with RA drug targets.

CONCLUSION

This study identified novel RA risk loci and highlighted that comprehensive genetic study can provide important information for RA pathogenesis and drug therapy.

IL-23 induces the expression of pro-osteogenic factors in osteoclasts

Background The mechanism for the new bone formation in ankylosing spondylitis (AS) is still unclear. Although it has been demonstrated that IL-23 plays a pivotal role in the pathophysiology of AS, IL-23 has no direct effects on osteoblasts but modulates the function of osteoclasts.

Aims To explore whether IL-23 indirectly facilitates new bone formation through osteoclasts in AS, here we analyzed whether IL-23 enhances the expression levels of pro-osteogenic factors by osteoclasts.

Methods Mononuclear cells were harvested from mouse bone marrow and cultured in the presence of M-CSF (50 ng/ml) and RANKL (30 ng/ml) to trigger the production of osteoclasts. Protein and mRNA expression levels of Semaphorin 4D, Ephrin B2, BMP2, BMP6, SPHK1, HtrA1 and Wnt10b were measured using Western blot and qRT-PCR.

Results Primary mononuclear cells were transformed into osteoclasts with RANKL and M-CSF. The increased expression of NFATc1 and TRAP together with TRAP staining of>3 nuclei were used to identify mature osteoclasts. The mRNA expression levels of BMP2, Ephrin B2 and SPHK1 were enhanced by 1.46, 2.1 and 2.46 folds after exposure to IL-23. Confirmation of increased levels of Ephrin B2 and SPHK1 in IL-23-stimulated osteoclasts was provided by Western blot analysis. IL-23 had no effects on the expression of BMP6 or Wnt10b, or on the anti-osteogenic factors Semaphorin 4D or HtrA1.

Conclusions IL-23 induces osteoclasts to express pro-osteogenic factors rather than anti-osteogenic factors, suggesting IL-23 might indirectly promote the differentiation of osteoblasts through activated osteoclasts in ankylosing spondylitis.

CD4+ CCR6+ T cells, but not γδ T cells, are important for the IL-23R-dependent progression of antigen-induced inflammatory arthritis in mice

IL‐23 plays an important role in the development of arthritis and the IL‐23 receptor (IL‐23R) is expressed on different types of T cells. However, it is not fully clear which IL‐23R⁺ T cells are critical in driving T cell‐mediated synovitis. We demonstrate, using knock‐in IL‐23R‐GFP reporter (IL‐23R^GFP/+) mice, that CD4⁺CCR6⁺ T cells and γδ T cells, but not CD8⁺ T cells, express the IL‐23R(GFP). During early arthritis, IL‐23R(GFP)⁺CD4⁺CCR6⁺ T cells, but not IL‐23R(GFP)⁺ γδ T cells, were present in the inflamed joints. IL‐23R^GFP/+ mice were bred as homozygotes to obtain IL‐23R^GFP/GFP (IL‐23R deficient/IL‐23R^−/−) mice, which express GFP under the IL‐23R promotor. Arthritis progression and joint damage were significantly milder in IL‐23R^−/− mice, which revealed less IL‐17A⁺ cells in their lymphoid tissues. Surprisingly, IL‐23R^−/− mice had increased numbers of IL‐23R(GFP)⁺CD4⁺CCR6⁺ and CCR7⁺CD4⁺CCR6⁺ T cells in their spleen compared to WT, and IL‐23 suppressed CCR7 expression in vitro. However, IL‐23R(GFP)⁺CD4⁺CCR6⁺ T cells were present in the synovium of IL‐23R^−/− mice at day 4. Finally, adoptive transfer experiments revealed that CD4⁺CCR6⁺ T cells and not γδ T cells drive arthritis progression. These data suggest that IL‐23R‐dependent T cell‐mediated synovitis is dependent on CD4⁺CCR6⁺ T cells and not on γδ T cells.

Responses to Cytokine Inhibitors Associated with Cellular Composition in Models of Immune-Mediated Inflammatory Arthritis

Objective

Immune‐mediated inflammatory arthritis (IMIA) is a heterogeneous group of diseases including rheumatoid arthritis (RA), psoriatic arthritis (PsA), and spondyloarthritis (SpA). Disease‐modifying antirheumatic drugs (DMARDs) target very different cellular components of the disease processes. Characterization of the pathobiological subtypes of IMIA could provide more specific treatment approaches for each disease. For example, RA has been proposed to consist of at least three synovial pathotypes (lymphoid, myeloid, and fibroid), and only a subgroup of RA patients have erosive disease. The objective of this study was to evaluate the effects of various DMARDs on different synovial cell subsets using human ex vivo models of IMIA.

Methods

Synovial fluid and blood samples were obtained from a study population consisting of patients with RA, PsA, or peripheral SpA with at least one swollen joint (n = 18). The DMARDs used in this study were methotrexate, adalimumab, etanercept, tocilizumab, anakinra, ustekinumab, secukinumab, tofacitinib, and baricitinib. Paired synovial fluid mononuclear cells (SFMCs), peripheral blood mononuclear cells (PBMCs), and fibroblast‐like synovial cells (FLSs) were used in three different previously optimized ex vivo models.

Results

In SFMCs cultured for 48 hours, all DMARDs except anakinra decreased the production of monocyte chemoattractant protein (MCP)‐1. In SFMCs cultured for 21 days, only the two tumor necrosis factor alpha (TNFα) inhibitors adalimumab and etanercept decreased the secretion of tartrate‐resistant acid phosphatase (P < 0.01, P < 0.001). In the FLS and PBMC 48‐hour co‐cultures, only tocilizumab (P < 0.001) and the two Janus kinase inhibitors tofacitinib and baricitinib (both P < 0.05) decreased the production of MCP‐1 by around 50%.

Conclusion

TNFα inhibition was effective in preventing inflammatory osteoclastogenesis, whereas tocilizumab, tofacitinib, and baricitinib had superior efficacy in cultures dominated by FLSs. Taken together, this study reveals that responses to cytokine inhibitors associate with cellular composition in models of IMIA. In particular, this study provides new evidence on the differential effect of DMARDs on leukocytes compared with stromal cells.

Impact of IL12B Polymorphisms on Genetic Susceptibility and IL-12p40 and IL-23 Serum Levels in Rheumatoid Arthritis

The aim of this study was to evaluate the possible association of IL12B gene polymorphisms with serum levels of IL-12p40, IL-23 and genetic susceptibility to rheumatoid arthritis (RA) in the Bulgarian population. Genotyping for IL12Bpro (rs17860508) and IL12B A/C - 3' UTR (rs3212227) polymorphisms was performed by polymerase chain reaction (PCR)-based methods in 125 RA patients and 239 healthy controls. The IL-23 and IL-12p40 serum levels were measured by enzyme-linked immunosorbent assay (ELISA). An association was established between the rs17860508 polymorphism and RA susceptibility in Bulgarian population with an increased frequency of rs17860508 minor allele-2 and homozygous genotype-22 in RA patients. The rs17860508 risk RA genotype-22 was also significantly correlated to elevated serum IL-23 in RA patients. Although, there was no association between the rs3212227 and genetic predisposition to RA, significantly increased serum levels of both Il-12p40 and IL-23 were observed in RA patients with the rs3212227 AA genotype. Furthermore, the distribution of haplotypes and genotype combination in our cohort indicated increased RA risk in individuals carrying the rs17860508/rs3212227 2/A haplotype or 2.2/AC+CC combination, while 1/A haplotype or 1.1/AA combination may be protective for RA. In conclusion, our study demonstrates a functional effect of IL12B polymorphisms on IL-12p40 and IL-23 cytokine levels in RA patients and suggests a leading role for IL12B rs17860508 in the genetic predisposition to RA, while IL12B rs3212227 significantly modify the RA risk in Bulgarian population.

p19-Targeting ILP Protein Blockers of IL-23/Th-17 Pro-Inflammatory Axis Displayed on Engineered Bacteria of Food Origin

IL-23-mediated Th-17 cell activation and stimulation of IL-17-driven pro-inflammatory axis has been associated with autoimmunity disorders such as Inflammatory Bowel Disease (IBD) or Crohn’s Disease (CD). Recently we developed a unique class of IL-23-specific protein blockers, called ILP binding proteins that inhibit binding of IL-23 to its cognate cell-surface receptor (IL-23R) and exhibit immunosuppressive effect on human primary blood leukocytes ex vivo. In this study, we aimed to generate a recombinant Lactococcus lactis strain which could serve as in vivo producer/secretor of IL-23 protein blockers into the gut. To achieve this goal, we introduced ILP030, ILP317 and ILP323 cDNA sequences into expression plasmid vector containing USP45 secretion signal, FLAG sequence consensus and LysM-containing cA surface anchor (AcmA) ensuring cell-surface peptidoglycan anchoring. We demonstrate that all ILP variants are expressed in L. lactis cells, efficiently transported and secreted from the cell and displayed on the bacterial surface. The binding function of AcmA-immobilized ILP proteins is documented by interaction with a recombinant p19 protein, alpha subunit of human IL-23, which was assembled in the form of a fusion with Thioredoxin A. ILP317 variant exhibits the best binding to the human IL-23 cytokine, as demonstrated for particular L.lactis-ILP recombinant variants by Enzyme-Linked ImmunoSorbent Assay (ELISA). We conclude that novel recombinant ILP-secreting L. lactis strains were developed that might be useful for further in vivo studies of IL-23-mediated inflammation on animal model of experimentally-induced colitis.