Gene expression analysis of rheumatoid arthritis synovial lining regions by cDNA microarray combined with laser microdissection: up-regulation of inflammation-associated STAT1, IRF1, CXCL9, CXCL10, and CCL5

STATs, promising targets for the treatment of autoimmune and inflammatory diseases

Cytokines play a crucial role in the pathophysiology of autoimmune and inflammatory diseases, with over 50 cytokines undergoing signal transduction through the Signal Transducers and Activators of Transcription (STAT) signaling pathway. Recent studies have solidly confirmed the pivotal role of STATs in autoimmune and inflammatory diseases. Therefore, this review provides a detailed summary of the immunological functions of STATs, focusing on exploring their mechanisms in various autoimmune and inflammatory diseases. Additionally, with the rapid advancement of structural biology in the field of drug discovery, many STAT inhibitors have been identified using structure-based drug design strategies. In this review, we also examine the structures of STAT proteins and compile the latest research on STAT inhibitors currently being tested in animal models and clinical trials for the treatment of immunological diseases, which emphasizes the feasibility of STATs as promising therapeutic targets and provides insights into the design of the next generation of STAT inhibitors.

The role of HDAC3 in inflammation: mechanisms and therapeutic implications

Histone deacetylases (HDACs) are critical regulators of inflammatory gene expression, and the efficacy of pan-HDAC inhibitors has been implicated in various disease conditions. However, it remains largely unclear how HDACs precisely regulate inflammation. To this end, evaluating the isoform-specific function of HDACs is critical, and the isoform-specific targeting could also circumvent the off-target effects of pan-HDAC inhibitors. This review provides an overview of the roles of HDAC3, a class I HDAC isoform, in modulating inflammatory responses and discusses the molecular mechanisms by which HDAC3 regulates inflammation associated with brain pathology, arthritis, cardiovascular diseases, lung pathology, allergic conditions, and kidney disorders. The articles also identify knowledge gaps in the field for future studies. Despite some conflicting reports, the selective inhibition of HDAC3 has been demonstrated to play a beneficial role in various inflammatory pathologies. Exploring the potential of HDAC3 inhibition to improve disease prognosis is a promising avenue requiring further investigation.

The Role of Mesenchymal Stromal Cells in the Treatment of Rheumatoid Arthritis

Rheumatoid arthritis (RA) is a chronic inflammatory joint disease characterised by the formation of a hyperplastic pannus, as well as cartilage and bone damage. The pathogenesis of RA is complex and involves broad interactions between various cells present in the inflamed synovium, including fibroblast-like synoviocytes (FLSs), macrophages, and T cells, among others. Under inflammatory conditions, these cells are activated, further enhancing inflammatory responses and angiogenesis and promoting bone and cartilage degradation. Novel treatment methods for RA are greatly needed, and mesenchymal stromal cells (MSCs) have been suggested as a promising new regenerative and immunomodulatory treatment. In this paper, we present the interactions between MSCs and RA-FLSs, and macrophages and T cells, and summarise studies examining the use of MSCs in preclinical and clinical RA studies.

Gene Expression Profiling to Unfolded Proteins Response as a Risk Modulator of Patients with Rheumatoid Arthritis

Rheumatoid arthritis (RA) is a chronic inflammatory disease. Despite new methods of diagnostics and treatment as well as extensive biological and immunosuppressive treatment, the etiology of RA is not fully understood. Moreover, the problem of diagnosis and treatment of RA patients is still current and affects a large group of patients. It is suggested that endoplasmic reticulum (ER)-related features may impair adaptation to chronic stress, inferring the risk of rheumatoid arthritis. The main goal in this study was evaluation of changes in mRNA translation to determine chronic ER stress conditions in rheumatoid arthritis patients. The study group consist of 86 individuals including a total of 56 rheumatoid arthritis patients and 30 healthy controls. The expression level of mRNA form blood samples of RA patients as well as controls of the unfolded protein response (UPR)-associated genes (p-eIF2, BCL-2, PERK, ATF4, and BAX) were investigated using real-time qPCR. GAPDH expression was used as a standard control. Considering the median, the expression levels of PERK, BCL-2, p-eIF2, ATF4, and BAX were found to be significantly increased in the blood of RA patients compared with the control group. The p-value for the PERK gene was 0.0000000036, the p-value for the BCL-2 gene was 0.000000014, the p-value for the p-eIF2 gene was 0.006948, the p-value for the ATF4 gene was 0.0000056, and the p-value for the BAX gene was 0.00019, respectively. Thus, it can be concluded that the targeting of the components of the PERK-dependent UPR signaling pathway via small-molecule PERK inhibitors may contribute to the development of novel, innovative treatment strategies against rheumatoid arthritis.

Plasma Circular-RNA 0005567 as a Potential Marker of Disease Activity in Rheumatoid Arthritis

Circular RNAs (circRNAs) are noncoding molecules and are generated through back splicing, during which the 5' and 3' ends are covalently joined. Consequently, the lack of free ends makes them stable and resistant to exonucleases, and they become more suitable biomarkers than other noncoding RNAs. The aim of the study was to find an association between selected circRNAs and disease activity in patients with RA. A total of 71 subjects, 45 patients with RA and 26 healthy controls (HCs), were enrolled. In the RA group, 24 patients had high disease activity (DAS-28-ESR > 5.1) and 21 individuals were in remission (DAS-28-ESR ≤ 2.6). The cell line SW982 was used to evaluate the biological function of circ_0005567. The concentration of circ_0005567 in RA patients was elevated compared to HCs (median, 177.5 [lower-upper quartile, 83.13-234.6] vs. 97.83 [42.03-145.4], p = 0.017). Patients with high disease activity had a higher concentration of circ_0005567 than the control group (185.4 [112.72-249.25] vs. 97.83 [42.03-145.4], p = 0.015). In the cell line model, we found an association between circ_0005567 and miR-194-5p concentration and increased expression of mRNAs that may be related to cell proliferation. The plasma concentration of circ_0005567 may be a new potential biomarker associated with disease activity in patients with RA.

Artificial intelligence in rheumatoid arthritis: potential applications and future implications

The widespread adoption of digital health records, coupled with the rise of advanced diagnostic testing, has resulted in an explosion of patient data, comparable in scope to genomic datasets. This vast information repository offers significant potential for improving patient outcomes and decision-making, provided one can extract meaningful insights from it. This is where artificial intelligence (AI) tools like machine learning (ML) and deep learning come into play, helping us leverage these enormous datasets to predict outcomes and make informed decisions. AI models can be trained to analyze and interpret patient data, including physician notes, laboratory testing, and imaging, to aid in the management of patients with rheumatic diseases. As one of the most common autoimmune diseases, rheumatoid arthritis (RA) has attracted considerable attention, particularly concerning the evolution of diagnostic techniques and therapeutic interventions. Our aim is to underscore those areas where AI, according to recent research, demonstrates promising potential to enhance the management of patients with RA.

Bone Marrow Mesenchymal Stem Cells Release miR-378a-5p-Carried Extracellular Vesicles to Alleviate Rheumatoid Arthritis

This study investigates whether bone marrow mesenchymal stem cell (BMSC)-derived extracellular vesicles (EVs) can affect rheumatoid arthritis (RA) by delivering microRNA (miR)-378a-5p to regulate the interferon regulatory factor 1/signal transducer and transcription 1 (IRF1/STAT1) axis. We identified RA-associated miRNAs using the GEO microarray dataset GSE121894. We found the most important miRNAs in RA synovial tissues using RT-qPCR. BMSC-derived EVs were ultracentrifuged and cocultured with human synovial microvascular endothelial cells (HSMECs) in vitro. Dual-luciferase and RNA immunoprecipitation studies examined miR-378a-5p's specific binding to IRF1. We also measured angiogenesis, migration, and proliferation using CCK-8, Transwell, and tube formation assays. Collagen-induced arthritis (CIA) mice models were created by inducing arthritis and scoring it. RA synovial tissues had low miR-378a-5p expression, whereas BMSC-derived EVs had high levels. The transfer of miR-378a-5p by BMSC-derived EVs to HSMECs boosted proliferation, migration, and angiogenesis. miR-378a-5p inhibited IRF1. MiR-378a-5p-containing BMSC-derived EVs decreased STAT1 phosphorylation and HSMEC IRF1 expression. EVs with miR-378a-5p mimic promoted HSMEC proliferation, migration, and angiogenesis, whereas dexmedetomidine inhibited STAT1 phosphorylation. In CIA mice, BMSC-derived EVs containing miR-378a-5p enhanced synovial vascular remodeling and histopathology. Thus, miR-378a-5p from BMSC-derived EVs promotes HSMEC proliferation, migration, and angiogenesis, inactivating the IRF1/STAT1 axis and preventing RA.

A review of the pleiotropic actions of the IFN-inducible CXC chemokine receptor 3 ligands in the synovial microenvironment

Chemokines are pivotal players in instigation and perpetuation of synovitis through leukocytes egress from the blood circulation into the inflamed articulation. Multitudinous literature addressing the involvement of the dual-function interferon (IFN)-inducible chemokines CXCL9, CXCL10 and CXCL11 in diseases characterized by chronic inflammatory arthritis emphasizes the need for detangling their etiopathological relevance. Through interaction with their mutual receptor CXC chemokine receptor 3 (CXCR3), the chemokines CXCL9, CXCL10 and CXCL11 exert their hallmark function of coordinating directional trafficking of CD4+ TH1 cells, CD8+ T cells, NK cells and NKT cells towards inflammatory niches. Among other (patho)physiological processes including infection, cancer, and angiostasis, IFN-inducible CXCR3 ligands have been implicated in autoinflammatory and autoimmune diseases. This review presents a comprehensive overview of the abundant presence of IFN-induced CXCR3 ligands in bodily fluids of patients with inflammatory arthritis, the outcomes of their selective depletion in rodent models, and the attempts at developing candidate drugs targeting the CXCR3 chemokine system. We further propose that the involvement of the CXCR3 binding chemokines in synovitis and joint remodeling encompasses more than solely the directional ingress of CXCR3-expressing leukocytes. The pleotropic actions of the IFN-inducible CXCR3 ligands in the synovial niche reiteratively illustrate the extensive complexity of the CXCR3 chemokine network, which is based on the intercommunion of IFN-inducible CXCR3 ligands with distinct CXCR3 isoforms, enzymes, cytokines, and infiltrated and resident cells present in the inflamed joints.

Identification of key candidate genes and pathways in rheumatoid arthritis and osteoarthritis by integrated bioinformatical analysis

Rheumatoid arthritis (RA) and osteoarthritis (OA) are the most common joint disorders. Although they have shown analogous clinical manifestations, the pathogenesis of RA and OA are different. In this study, we used the online Gene Expression Omnibus (GEO) microarray expression profiling dataset GSE153015 to identify gene signatures between RA and OA joints. The relevant data on 8 subjects obtained from large joints of RA patients (RA-LJ), 8 subjects obtained from small joints of RA patients (RA-SJ), and 4 subjects with OA were investigated. Differentially expressed genes (DEGs) were screened. Functional enrichment analysis of DEGs including the Gene Ontology terms and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathways were identified, which were mainly associated with T cell activation or chemokine activity. Besides, protein-protein interaction (PPI) network analysis was performed, and key modules were identified. Hub genes of RA-LJ and OA groups were screened, they were CD8A, GZMB, CCL5, CD2, and CXCL9, whereas CD8A, CD2, IL7R, CD27, and GZMB were hub genes of RA-SJ and OA group. The novel DEGs and functional pathways between RA and OA identified in this study may provide new insight into the underlying molecular mechanisms and therapeutic strategies of RA and OA.

Regulation of type I interferon signature by VGLL3 in the fibroblast-like synoviocytes of rheumatoid arthritis patients via targeting the Hippo pathway

Background

The upregulation of interferon (IFN)-stimulated genes induced by type I IFNs (namely type I IFN signature) in rheumatoid arthritis (RA) patients had implications in early diagnosis and prediction of therapy responses. However, factors that modulate the type I IFN signature in RA are largely unknown. In this study, we aim to explore the involvement of VGLL3, a homologue of the vestigial-like gene in Drosophila and a putative regulator of the Hippo pathway, in the modulation of type I IFN signature in the fibroblast-like synoviocytes (FLS) of RA patients.

Methods

FLS were isolated from RA and osteoarthritis (OA) patients. Expression of VGLL3 in the synovial tissues and FLS was analyzed by immunohistochemistry and PCR. RNA sequencing was performed in RA-FLS upon VGLL3 overexpression. The expression of IFN-stimulated genes was examined by PCR and Western blotting.

Results

VGLL3 was upregulated in the RA synovium and RA-FLS compared to OA. Overexpression of VGLL3 promoted the expression of IFN-stimulated genes in RA-FLS. The expression of STAT1 and MX1 was also upregulated in RA synovium compared to OA and was associated with the expression of VGLL3 in RA and OA patients. VGLL3 promoted the IRF3 activation and IFN-β1 expression in RA-FLS. Increased IFN-β1 induced the expression of IFN-stimulated genes in RA-FLS in an autocrine manner. VGLL3 also modulated the expression of the Hippo pathway molecules WWTR1 and AMOTL2, which mediated the regulation of IRF3 activation and IFN-β1 production by VGLL3 in RA-FLS.

Conclusions

VGLL3 drives the IRF3-induced IFN-β1 expression in RA-FLS by inhibiting WWTR1 expression and subsequently promotes the type I IFN signature expression in RA-FLS through autocrine IFN-β1 signaling.

Bioinformatics-Led Discovery of Osteoarthritis Biomarkers and Inflammatory Infiltrates

The molecular mechanisms of osteoarthritis, the most common chronic disease, remain unexplained. This study aimed to use bioinformatic methods to identify the key biomarkers and immune infiltration in osteoarthritis. Gene expression profiles (GSE55235, GSE55457, GSE77298, and GSE82107) were selected from the Gene Expression Omnibus database. A protein-protein interaction network was created, and functional enrichment analysis and genomic enrichment analysis were performed using the Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genome (KEGG) databases. Immune cell infiltration between osteoarthritic tissues and control tissues was analyzed using the CIBERSORT method. Identify immune patterns using the ConsensusClusterPlus package in R software using a consistent clustering approach. Molecular biological investigations were performed to discover the important genes in cartilage cells. A total of 105 differentially expressed genes were identified. Differentially expressed genes were enriched in immunological response, chemokine-mediated signaling pathway, and inflammatory response revealed by the analysis of GO and KEGG databases. Two distinct immune patterns (ClusterA and ClusterB) were identified using the ConsensusClusterPlus. Cluster A patients had significantly lower resting dendritic cells, M2 macrophages, resting mast cells, activated natural killer cells and regulatory T cells than Cluster B patients. The expression levels of TCA1, TLR7, MMP9, CXCL10, CXCL13, HLA-DRA, and ADIPOQSPP1 were significantly higher in the IL-1β-induced group than in the osteoarthritis group in an in vitro qPCR experiment. Explaining the differences in immune infiltration between osteoarthritic tissues and normal tissues will contribute to the understanding of the development of osteoarthritis.

General Caspase Inhibition in Primary Chondrogenic Cultures Impacts Their Transcription Profile Including Osteoarthritis-Related Factors

OBJECTIVE

The knowledge about functions of caspases, usually associated with cell death and inflammation, keeps expanding also regarding cartilage. Active caspases are present in the growth plate, and caspase inhibition in limb-derived chondroblasts altered the expression of osteogenesis-related genes. Caspase inhibitors were reported to reduce the severity of cartilage lesions in osteoarthritis (OA), and caspase-3 might represent a promising biomarker for OA prognosis. The objective of this investigation was to decipher the transcriptomic regulation of caspase inhibition in chondrogenic cells.

DESIGN

Limb-derived chondroblasts were cultured in the presence of 2 different inhibitors: Z-VAD-FMK (FMK) and Q-VD-OPH (OPH). A whole transcriptome RNA sequencing was performed as the key analysis.

RESULTS

The analysis revealed a statistically significant increase in the expression of 252 genes in the FMK samples and 163 genes in the OPH samples compared with controls. Conversely, there was a significant decrease in the expression of 290 genes in the FMK group and 188 in the OPH group. Among the top up- and downregulated genes (more than 10 times changed), almost half of them were associated with OA. Both inhibitors displayed the highest upregulation of the inflammatory chemokine Ccl5, the most downregulated gene was the one for mannose receptors Mrc1.

CONCLUSIONS

The obtained datasets pointed to a significant impact of caspase inhibition on the expression of several chondro-/osteogenesis-related markers in an in vitro model of endochondral ossification. Notably, the list of these genes included some encoding for factors associated with cartilage/bone pathologies such as OA.

Elevated Levels of IL-27 Are Associated with Disease Activity in Patients with Crohn's Disease

Immune disorders play an important role in the pathogenesis of Crohn's disease (CD). Notably, the increased immune response of Th1 cells and related cytokines is associated with the onset of CD. IL-27 is a newly discovered IL-12-related cytokine, but its expression and clinical significance in CD patients are still controversial. This study is aimed at evaluating the serum levels of IL-27 in CD patients and analyzing their clinical significance. The results indicated that serum levels of IL-27 in CD patients were significantly higher than those in control subjects (median (interquartile range (IQR)): 110.0 (95.0, 145.0) vs. 85.0 (80.0, 95.0) pg/ml, P < 0.001). Furthermore, the IL-27 levels significantly increased in CD patients at the active stage compared with CD patients in remission (CDR) (127.5 (100.0, 150.0) vs. 90 (80.0, 110.0) pg/ml, P < 0.001). However, there was no difference in IL-27 levels between CDR and control subjects. The levels of IL-27 were positively correlated with Crohn's disease activity index (CDAI), C-reactive protein (CRP), erythrocyte sedimentation rate (ESR), fecal calprotectin (FC), and Simple Endoscopic Score for Crohn's Disease (SES-CD) and negatively correlated with hemoglobin (Hb) and serum albumin (ALB). IL-27 combined with CRP favored the prediction of CD activity (area under the curve (AUC): 0.88). Additionally, the proportions of Th17 and Th1 cells in peripheral blood were higher in CD patients than in control subjects. Active CD patients exhibited significantly higher proportions of Th17 and Th1 cells than those in remission. Moreover, correlation analysis indicated that the serum levels of IL-27 were positively associated with the frequency of Th17 cells in CD patients (r = 0.519, P = 0.013) but not associated with the frequency of Th1 cells in CD patients. IL-27 is positively associated with multiple inflammation indicators and may exert a proinflammatory profile by regulating Th17 cell differentiation in the development of Crohn's disease. In the future, IL-27 combined with CRP is expected to become an important biological marker of CD activity.

Identifying the hub genes and immune cell infiltration in synovial tissue between osteoarthritic and rheumatoid arthritic patients by bioinformatic approach

BACKGROUND

Osteoarthritis (OA) and rheumatoid arthritis (RA) are two common diseases that result in limb disability and a decrease in quality of life. The major symptoms of OA and RA are pain, swelling, stiffness, and malformation of joints, and each disease also has unique characteristics.

OBJECTIVE

To compare the pathological mechanisms of OA and RA via weighted correlation network analysis (WGCNA) and immune infiltration analysis and find potential diagnostic and pharmaceutical targets for the treatment of OA and RA.

METHODS

The gene expression profiles of ten OA and ten RA synovial tissue samples were downloaded from the Gene Expression Omnibus (GEO) database (GSE55235). After obtaining differentially expressed genes (DEGs) via GEO2R, WGCNA was conducted using an R package, and modules and genes that were highly correlated with OA and RA were identified. Gene Ontology (GO), Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment, and protein-protein interaction (PPI) network analyses were also conducted. Hub genes were identified using the Search Tool for the Retrieval of Interacting Genes (STRING) and Cytoscape software. Immune infiltration analysis was conducted using the Perl program and CIBERSORT software.

RESULTS

Two hundred ninety-nine DEGs, 24 modules, 16 GO enrichment terms, 6 KEGG pathway enrichment terms, 10 hub genes (CXCL9, CXCL10, CXCR4, CD27, CD69, CD3D, IL7R, STAT1, RGS1, and ISG20), and 8 kinds of different infiltrating immune cells (plasma cells, CD8 T cells, activated memory CD4 T cells, T helper follicular cells, M1 macrophages, Tregs, resting mast cells, and neutrophils) were found to be involved in the different pathological mechanisms of OA and RA.

CONCLUSION

Inflammation-associated genes were the top differentially expressed hub genes between OA and RA, and their expression was downregulated in OA. Genes associated with lipid metabolism may have upregulated expression in OA. In addition, immune cells that participate in the adaptive immune response play an important role in RA. OA mainly involves immune cells that are associated with the innate immune response.

Comparison of the Effects of Chemokine Receptors CXCR2 and CXCR3 Pharmacological Modulation in Neuropathic Pain Model-In Vivo and In Vitro Study

Recent findings have highlighted the roles of CXC chemokine family in the mechanisms of neuropathic pain. Our studies provide evidence that single/repeated intrathecal administration of CXCR2 (NVP-CXCR2-20) and CXCR3 ((±)-NBI-74330) antagonists explicitly attenuated mechanical/thermal hypersensitivity in rats after chronic constriction injury of the sciatic nerve. After repeated administration, both antagonists showed strong analgesic activity toward thermal hypersensitivity; however, (±)-NBI-74330 was more effective at reducing mechanical hypersensitivity. Interestingly, repeated intrathecal administration of both antagonists decreased the mRNA and/or protein levels of pronociceptive interleukins (i.e., IL-1beta, IL-6, IL-18) in the spinal cord, but only (±)-NBI-74330 decreased their levels in the dorsal root ganglia after nerve injury. Furthermore, only the CXCR3 antagonist influenced the spinal mRNA levels of antinociceptive factors (i.e., IL-1RA, IL-10). Additionally, antagonists effectively reduced the mRNA levels of pronociceptive chemokines; NVP-CXCR2-20 decreased the levels of CCL2, CCL6, CCL7, and CXCL4, while (±)-NBI-74330 reduced the levels of CCL3, CCL6, CXCL4, and CXCL9. Importantly, the results obtained from the primary microglial and astroglial cell cultures clearly suggest that both antagonists can directly affect the release of these ligands, mainly in microglia. Interestingly, NVP-CXCR2-20 induced analgesic effects after intraperitoneal administration. Our research revealed important roles for CXCR2 and CXCR3 in nociceptive transmission, especially in neuropathic pain.

Decreased Levels of STAT1 and Interferon-γ-Induced STAT1 Phosphorylation in Rheumatoid Arthritis CD4 and CD8 T Cells

Objective

We investigated whether a previously reported association of IFNGR expression with rheumatoid arthritis (RA) and its radiographic severity reflects differences in proximal interferon‐γ (IFN‐γ) signaling in T cells from patients with RA compared with healthy controls (HC).

Methods

Using phosphoflow cytometry, we compared IFN‐γ–stimulated signal transducer and activator of transcription 1 (STAT1) activation in CD4⁺ and CD8⁺ T‐cell populations from patients with RA and HC.

Results

Compared with controls, patients with RA had a higher proportion of CD4⁺ T cells, associated with expansion of the CD4⁺ effector memory subset. Several CD4⁺ T‐cell types exhibited reduced IFN‐γ–induced phosphoSTAT1^Y701 (pSTAT1^Y701) in patients with RA compared with HC. Engaging the T‐cell receptor (TCR) complex on CD4⁺ T cells during IFN‐γ stimulation abrogated the reduction in STAT1 activation in patients with RA but had no effect in HC. The phosphorylation of STAT1^S727 was similar in CD4⁺ T cells from patients with RA and HC. In contrast to CD4⁺ T cells, IFN‐γ–induced pSTAT1^Y701 levels in CD8⁺ T cells were equivalent or higher in patients with RA compared with HC. Total STAT1 levels (phosphorylated + unphosphorylated) were lower in CD4⁺ and CD8⁺ T cells from patients with RA compared with HC.

Conclusion

We report diminished IFN‐γ–induced pSTAT1^Y701 levels in CD4⁺ T cells in patients with RA, which were restored by TCR engagement. There were lower levels of total STAT1 in patients with RA compared with HC, but this likely does not explain diminished IFN‐γ–induced pSTAT1^Y701 levels in CD4⁺ T cells because activation in CD8⁺ T cells was higher or equivalent to that seen in HC. The enhanced IFNGR expression in patients with RA reported previously may reflect a compensatory mechanism to overcome deficiency in IFN‐γ responsiveness.

MiR-467b alleviates lipopolysaccharide-induced inflammation through targeting STAT1 in chondrogenic ATDC5 cells

Osteoarthritis (OA) is one of the most common degenerative joint diseases worldwide. Chondrocytes are activated in OA patients, accompanied by excessive chondrogenic proliferation and production of inflammatory cytokines. MiR-467b is implicated in the regulation of artherosclerosis and pro-inflammatory cytokine secretion. However, the precise role of miR-467b in OA remains unclear. In the present study, we induced inflammation in chondrogenic ATDC5 cells using lipopolysaccharide (LPS). LPS treatment significantly elevated the production of interleukin-6 (IL-6), IL-1β and tumour necrosis factor-α (TNF-α) in ATDC5 cells, accompanied by decreased miR-467 level. Then, we over-expressed miR-467b using its specific mimics in ATDC5 cells, and LPS-induced inflammation was significantly inhibited as evidenced by decreased IL-6, IL-1β and TNF-α levels. MiR-467b agomir also alleviated inflammation in rat knee osteoarthritis (KOA) model. In addition, we validated that signal transducer and activator of transcription 1 (STAT1) was a downstream target of miR-467b. LPS treatment significantly increased the STAT1 expression while miR-467b mimic transfection partially reversed this effect. Moreover, STAT1 knockout reversed the increased contents of IL-6, IL-1β and TNF-α. Furthermore, miR-467b over-expression significantly decreased the production of IL-6, IL-1β and TNF-α induced by LPS treatment, which was partially reversed by further STAT1 over-expression. In summary, our findings demonstrated that miR-467b alleviated LPS-induced inflammation through targeting STAT1, and this miR-467b/STAT1 regulation axis may provide a new therapeutic target for OA clinical management.

Working and safety profiles of JAK/STAT signaling inhibitors. Are these small molecules also smart?

The Janus kinase (JAK)/signal transducers and activators of transcription (STAT) pathway is an important intracellular route through which many different extracellular soluble molecules, by reaching membrane receptors, can signal the nucleus. The spectrum of soluble molecules that use the JAK/STAT pathway through their corresponding receptors is quite large (almost 50 different molecules), and includes some cytokines involved in the pathogenesis of many immune-mediated diseases. Such diseases, when left untreated, present an evident hyperactivation of JAK/STAT signaling. Therefore, given the pathogenetic role of JAK/STAT, drugs known as JAK inhibitors (JAKi), that target one or more JAKs, have been developed to counteract JAK/STAT signal hyperactivation. As some hematological malignancies present an intrinsic JAK/STAT hyperactivation due to a JAK mutation, some JAKi have also been successfully used in this context. Regulatory agencies for drug administration in different countries have already approved a few JAKi in the setting of either immune-mediated diseases or hematological malignancies. Aim of this review is to describe the physiology of intracellular JAK/STAT pathway signaling and the pathological conditions associated to its dysregulation. Then, the rationale for targeting JAK in rheumatic autoimmune diseases is discussed, along with clinical data from registration studies showing the efficacy of these drugs. Finally, the excellent safety profile of JAKi is discussed in the context of the apparent poor specificity of JAK/STAT pathway signal.

IL-21 gene rs6822844 polymorphism and rheumatoid arthritis susceptibility

Interleukin-21 (IL-21) is a cytokine that plays a crucial role in pathogenesis and activity of the rheumatoid arthritis (RA). Meanwhile, genetic polymorphisms in the IL-21 gene may alter its expression. Previous studies have reported conflicting results assessing the association between the IL-21 rs6822844 G/T polymorphism and RA risk. Thus, it's necessary to perform a meta-analysis to definite above relationship. PubMed database was searched for all papers published until October 20, 2019. Nine case-control studies with 9998 cases and 10742 controls were retrieved based on the search criteria at last. Odds ratio (95% confidence interval) was used to calculate the strength of this association. Publication bias was detected using both Begg's and Egger's tests. Overall, the IL-21 rs6822844 G/T polymorphism was found to be significantly associated with decreased RA risk (e.g. T-allele versus G-allele: OR = 0.81, 95% CI = 0.72-0.91, P < 0.001). In addition, decreased RA risk was also detected both in Asians (eg: TT+TG versus GG: OR = 0.42, 95% CI = 0.31-0.56, P < 0.001) and Caucasians (eg: TT+TG versus GG: OR = 0.85, 95% CI = 0.80-0.91, P < 0.001). A similar trend in association was found in the source of the control and genotype method subgroups. Furthermore, subgroup analysis of rheumatoid factor status revealed a protective relationship between the IL-21 rs6822844 G/T polymorphism and RF+/RF- RA risk. A similar relationship was noted in the anti-citrullinated protein antibody status subgroup. The results of the present study suggest that the IL-21 rs6822844 G/T polymorphism was significantly associated with decreased RA susceptibility.

Hesperidin methyl chalcone interacts with NFκB Ser276 and inhibits zymosan-induced joint pain and inflammation, and RAW 264.7 macrophage activation

Arthritis can be defined as a painful musculoskeletal disorder that affects the joints. Hesperidin methyl chalcone (HMC) is a flavonoid with analgesic, anti-inflammatory, and antioxidant effects. However, its effects on a specific cell type and in the zymosan-induced inflammation are unknown. We aimed at evaluating the effects of HMC in a zymosan-induced arthritis model. A dose-response curve of HMC (10, 30, or 100 mg/kg) was performed to determine the most effective analgesic dose after intra-articular zymosan stimuli. Knee joint oedema was determined using a calliper. Leukocyte recruitment was performed by cell counting on knee joint wash as well as histopathological analysis. Oxidative stress was measured by colorimetric assays (GSH, FRAP, ABTS and NBT) and RT-qPCR (gp91^phox and HO-1 mRNA expression) performed. In vitro, oxidative stress was assessed by DCFDA assay using RAW 264.7 macrophages. Cytokine production was evaluated in vivo and in vitro by ELISA. In vitro NF-κB activation was analysed by immunofluorescence. We observed HMC reduced mechanical hypersensitivity and knee joint oedema, leukocyte recruitment, and pro-inflammatory cytokine levels. We also observed a reduction in zymosan-induced oxidative stress as per increase in total antioxidant capacity and reduction in gp91^phox and increase in HO-1 mRNA expression. Accordingly, total ROS production and macrophage NFκB activation were diminished. HMC interaction with NFκB p65 at Ser276 was revealed using molecular docking analysis. Thus, data presented in this work suggest the usefulness of HMC as an analgesic and anti-inflammatory in a zymosan-induced arthritis model, possibly by targeting NFκB activation in macrophages.

New Developments in Transcriptomic Analysis of Synovial Tissue

Transcriptomic technologies are constantly changing and improving, resulting in an ever increasing understanding of gene expression in health and disease. These technologies have been used to investigate the pathological changes occurring in the joints of rheumatoid arthritis patients, leading to discoveries of disease mechanisms, and novel potential therapeutic targets. Microarrays were initially used on both whole tissue and cell subsets to investigate research questions, with bulk RNA sequencing allowing for further elaboration of these findings. A key example is the classification of pathotypes in rheumatoid arthritis using RNA sequencing that had previously been discovered using microarray and histology. Single-cell sequencing has now delivered a step change in understanding of the diversity and function of subpopulations of cells, in particular synovial fibroblasts. Future technologies, such as high resolution spatial transcriptomics, will enable step changes integrating single cell transcriptomic and geographic data to provide an integrated understanding of synovial pathology.

Analysis of gene expression in rheumatoid arthritis and related conditions offers insights into sex-bias, gene biotypes and co-expression patterns

The era of next-generation sequencing has mounted the foundation of many gene expression studies. In rheumatoid arthritis research, this has led to the discovery of important candidate genes which offered novel insights into mechanisms and their possible roles in the cure of the disease. In the last years, data generation has outstripped data analysis and while many studies focused on specific aspects of the disease, a global picture of the disease is not yet accomplished. Here, we analyzed and compared a collection of gene expression information from healthy individuals and from patients suffering under different arthritis conditions from published studies containing the following clinical conditions: early and established rheumatoid arthritis, osteoarthritis and arthralgia. We show comprehensive overviews of this data collection and give new insights specifically on gene expression in the early stage, into sex-dependent gene expression, and we describe general differences in expression of different biotypes of genes. Many genes that are related to cytoskeleton changes (actin filament related genes) are differently expressed in early rheumatoid arthritis in comparison to healthy subjects; interestingly, eight of these genes reverse their expression ratio significantly between men and women compared early rheumatoid arthritis and healthy subjects. There are some slighter changes between men and woman between the conditions early and established rheumatoid arthritis. Another aspect are miRNAs and other gene biotypes which are not only promising candidates for diagnoses but also change their expression grossly in average at rheumatoid arthritis and arthralgia compared to the healthy condition. With a selection of intersecting genes, we were able to generate simple classification models to distinguish between healthy and rheumatoid arthritis as well as between early rheumatoid arthritis to other arthritides based on gene expression.

IRF1 is critical for the TNF-driven interferon response in rheumatoid fibroblast-like synoviocytes : JAKinibs suppress the interferon response in RA-FLSs

Rheumatoid arthritis (RA) is an autoimmune disease characterized by persistent synovial inflammation. The major drivers of synovial inflammation are cytokines and chemokines. Among these molecules, TNF activates fibroblast-like synoviocytes (FLSs), which leads to the production of inflammatory mediators. Here, we show that TNF regulates the expression of the transcription factor interferon regulatory factor 1 (IRF1) in human FLSs as well as in a TNF transgenic arthritis mouse model. Transcriptomic analyses of IRF1-deficient, TNF-stimulated FLSs define the interferon (IFN) pathway as a major target of IRF1. IRF1 expression is associated with the expression of IFNβ, which leads to the activation of the JAK-STAT pathway. Blocking the JAK-STAT pathway with the Janus kinase inhibitor (JAKinib) baricitinib or tofacitinib reduces the expression of IFN-regulated genes (IRGs) in TNF-activated FLSs. Therefore, we conclude that TNF induces a distinct inflammatory cascade, in which IRGs are key elements, in FLSs. The IFN-signature might be a promising biomarker for the efficient and personalized use of new treatment strategies for RA, such as JAKinibs.

Overexpression of miR-101 May Target DUSP1 to Promote the Cartilage Degradation in Rheumatoid Arthritis

This study aimed to explore crucial genes that contribute to the development of rheumatoid arthritis (RA). Three GSE77298, GSE55457, and GSE55235 data sets were used to analyze the differentially expressed genes (DEGs) between RA synovial membrane tissue samples and normal synovial membrane tissue samples. Then, the functional enrichment analysis and protein-protein interactions (PPIs) construction were performed for DEGs. Subsequently, submodule analysis and regulatory network that contained transcription factors (TFs), microRNAs, and their targets were conducted. Finally, small-molecule drugs related to the DEGs were predicted. A total of 173 upregulated and 54 downregulated DEGs identified in at least 2 of 3 data sets. TYROBP, CTSS, MMP9, CXCR4, and CXCL10 were both highlighted in the PPI and submodule networks. In addition, miR-101, IRF1 TF, DUSP1, and CXCR4 had high degree in the regulatory network, and regulation pairs of miR-101-DUSP1 and IRF1 TF-CXCR4 were obtained. Drugs such as alemtuzumab and marimastat were negatively related to expression of the DEGs and might be useful drugs for RA treatment. In addition, most DEGs were involved in innate immune response (e.g., TYROBP, CCL5, CXCL10, FCGR1A, and FCGR3B) and phagosome pathway (e.g., CTSS). We suggested that miR-101 that regulated DUSP1, IRF1 TF that regulated CXCR4, as well as DEGs as TYROBP and CTSS might contribute to the RA pathogenesis. In addition, anti-inflammatory agent alemtuzumab and matrix metalloproteinase inhibitor marimastat might be useful drugs for RA treatment through functioning on their target genes.

FOXO3 is involved in the tumor necrosis factor-driven inflammatory response in fibroblast-like synoviocytes

Fibroblast-like synoviocytes (FLS) are major contributors to joint inflammation in rheumatoid arthritis (RA). Forkhead box O 3 (FOXO3) perturbations in immune cells are increasingly linked to RA pathogenesis. Here, we show that FOXO3 is distinctly inactivated/phosphorylated in the FLS of rheumatoid synovitis. In vitro, stimulation of FLS with tumor necrosis factor-alpha α (TNFα) induced a rapid and sustained inactivation of FOXO3. mRNA profiling revealed that the inactivation of FOXO3 is important for the sustained pro-inflammatory interferon response to TNFα (CXCL9, CXCL10, CXCL11, and TNFSF18). Mechanistically, our studies demonstrate that the inactivation of FOXO3 results from TNF-induced downregulation of phosphoinositide-3-kinase-interacting protein 1 (PIK3IP1). Thus, we identified FOXO3 and its modulator PIK3IP1 as a critical regulatory circuit for the inflammatory response of the resident mesenchymal cells to TNFα and contribute insight into how the synovial tissue brings about chronic inflammation that is driven by TNFα.

CCL5 and related genes might be the potential diagnostic biomarkers for the therapeutic strategies of rheumatoid arthritis

OBJECTIVE

Rheumatoid arthritis (RA) is a common disease of rheumatic diseases. The aim of this study was to identify gene signatures in RA and uncover their potential mechanisms.

METHOD

Gene expression profiles of GSE1919, GSE55235, GSE55457, and GSE77928 were downloaded from GEO database. The above four series contained 76 samples, including 44 RA patients and 32 normal controls. The gene ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway enrichment analyses were performed, and protein-protein interaction (PPI) network of the differentially expressed genes (DEGs) was constructed by Cytoscape software.

RESULTS

Up-regulated DEGs were significantly enriched in biological processes, including immune response, positive regulation of immune system process and regulation of immune system process, while down-regulated DEGs were significantly enriched in biological processes, including response to oxygen-containing compound, cellular lipid metabolic process, and lipid metabolic process. KEGG pathway analysis showed the up-regulated DEGs were enriched in cytokine-cytokine receptor interaction, chemokine signaling pathway, and primary immunodeficiency. The 104 hub genes, which were significantly differently expressed between patients and normal controls in at least two datasets, were identified from the PPI network, and subnetworks revealed that these genes were involved in significant pathways, including cytokine-cytokine receptor interaction, chemokine signaling pathway, and primary immunodeficiency.

CONCLUSION

The present study indicated that the identified DEGs and hub genes promote our understanding of molecular mechanisms underlying the development of RA, such as C-C motif chemokine 5 (CCL5), might have a negative impact in the development of RA. CCL5 and its related genes might be the potential diagnostic biomarkers for the therapeutic strategies of RA.

Synovial Tissue Heterogeneity in Rheumatoid Arthritis and Changes With Biologic and Targeted Synthetic Therapies to Inform Stratified Therapy

The treatment of rheumatoid arthritis (RA) has been transformed with the introduction of biologic disease modifying anti-rheumatic drugs (bDMARD) and more recently, targeted synthetic DMARD (tsDMARD) therapies in the form of janus-kinase inhibitors. Nevertheless, response to these agents varies such that a trial and error approach is adopted; leading to poor patient quality of life, and long-term outcomes. There is thus an urgent need to identify effective biomarkers to guide treatment selection. A wealth of research has been invested in this field but with minimal progress. Increasingly recognized is the importance of evaluating synovial tissue, the primary site of RA, as opposed to peripheral blood-based investigation. In this mini-review, we summarize the literature supporting synovial tissue heterogeneity, the conceptual basis for stratified therapy. This includes recognition of distinct synovial pathobiological subtypes and associated molecular pathways. We also review synovial tissue studies that have been conducted to evaluate the effect of individual bDMARD and tsDMARD on the cellular and molecular characteristics, with a view to identifying tissue predictors of response. Initial observations are being brought into the clinical trial landscape with stratified biopsy trials to validate toward implementation. Furthermore, development of tissue based omics technology holds still more promise in advancing our understanding of disease processes and guiding future drug selection.

Compendium of synovial signatures identifies pathologic characteristics for predicting treatment response in rheumatoid arthritis patients

Rheumatoid arthritis (RA) is therapeutically challenging due to patient heterogeneity and variability. Herein we describe a novel integration of RA synovial genome-scale transcriptomic profiling of different patient cohorts that can be used to provide predictive insights on drug responses. A normalized compendium consisting of 256 RA synovial samples that cover an intersection of 11,769 genes from 11 datasets was build and compared with similar datasets derived from OA patients and healthy controls. Differentially expression genes (DEGs) that were identified in three independent methods were fed into functional network analysis, with subsequent grouping of the samples based on a non-negative matrix factorization method. RA-relevant pathway activation scores and four machine learning classification techniques supported the generation of a predictive model of patient treatment response. We identified 876 up-regulated DEGs including 24 known genetic risk factors and 8 drug targets. DEG-based subgrouping revealed 3 distinct RA patient clusters with distinct activity signatures for RA-relevant pathways. In the case of infliximab, we constructed a classifier of drug response that was highly accurate with an AUC/AUPR of 0.92/0.86. The most informative pathways in achieving this performance were the NFκB-, FcεRI- TCR-, and TNF signaling pathways. Similarly, the expression of the HMMR, PRPF4B, EVI2A, RAB27A, MALT1, SNX6, and IFIH1 genes contributed in predicting the patient outcome. Construction and analysis of normalized synovial transcriptomic compendia can provide useful insights for understanding RA-related pathway involvement and drug responses for individual patients.

The immunologic constant of rejection classification refines the prognostic value of conventional prognostic signatures in breast cancer

Background

The immunologic constant of rejection (ICR) is a broad phenomenon of Th-1 immunity-mediated, tissue-specific destruction.

Methods

We tested the prognostic value of a 20-gene ICR expression signature in 8766 early breast cancers.

Results

Thirty-three percent of tumours were ICR1, 29% ICR2, 23% ICR3, and 15% ICR4. In univariate analysis, ICR4 was associated with a 36% reduction in risk of metastatic relapse when compared with ICR1-3 (p = 2.30E–03). In multivariate analysis including notably the three major prognostic signatures (Recurrence score, 70-gene signature, ROR-P), ICR was the strongest predictive variable (p = 9.80E–04). ICR showed no prognostic value in the HR+/HER2− subtype, but prognostic value in the HER2+ and TN subtypes. Furthermore, in each molecular subtype and among the tumours defined as high risk by the three prognostic signatures, ICR4 patients had a 41–75% reduction in risk of relapse as compared with ICR1-3 patients. ICR added significant prognostic information to that provided by the clinico-genomic models in the overall population and in each molecular subtype. ICR4 was independently associated with achievement of pathological complete response to neoadjuvant chemotherapy (p = 2.97E–04).

Conclusion

ICR signature adds prognostic information to that of current proliferation-based signatures, with which it could be integrated to improve patients’ stratification and guide adjuvant treatment.

The importance of chemokines in neuropathic pain development and opioid analgesic potency

The treatment of neuropathic pain resulting from nervous system malfunction remains a challenging problem for doctors and scientists. The lower effectiveness of conventionally used analgesics in neuropathic pain is associated with complex and not fully understood mechanisms of its development. Undoubtedly, interactions between immune and nervous system are crucial for maintenance of painful neuropathy. Nerve injury induces glial cell activation and thus enhances the production of numerous pronociceptive factors by these cells, including interleukins and chemokines. Increased release of those factors reduces the analgesic efficacy of opioids, which is significantly lower in neuropathic pain than in other painful conditions. This review discusses the role of chemokines from all four subfamilies as essential mediators of neuron-glia interactions occurring under neuropathic pain conditions. Based on available data, we analyse the influence of chemokines on opioid properties. Finally, we identify new direct and indirect pharmacological targets whose modulation may result in effective therapy of neuropathic pain, possibly in combination with opioids.

Biomarkers identification for acute myocardial infarction detection via weighted gene co-expression network analysis

The study aimed to seek potential biomarkers for acute myocardial infarction (AMI) detection and treatment.The dataset GSE48060 was used, consisting of 52 peripheral blood samples (31 AMI samples and 21 normal controls). By limma package, differentially expressed genes (DEGs) between 2 kinds of samples were identified, followed by enrichment analysis, subpathway analysis, protein-protein interaction (PPI) network analysis, and transcription factor network (TFN) analysis. Weighted gene co-expression network analysis was used to further extract key modules relating to AMI, followed by enrichment and TFN analyses. Expression validation was performed via meta-analysis of 2 datasets, GSE22229 and GSE29111.A set of 428 DEGs in AMI were screened out, and the upregulated toll-like receptor (TLR) family genes (TLR1, TLR2, and TLR10) were enriched in wound response, immune response and inflammatory response functions, and downregulated genes (GBP5, CXCL5, GZMA, CCL5, and CCL4) were correlated with immune response. CCL5, GZMA, GZMB, TLR2, and formyl peptide receptor 1 (FPR1) were predicted as crucial nodes in the PPI network. Signal transducer and activator of transcription 1 (STAT1) was the key transcription factor (TF) with multiple targets. The grey module was highly related to AMI. Genes in this module were closely related to regulation of macrophage activation, and spermatogenic leucine zipper 1 (SPZ1) was identified as a TF. Expressions of TLR2 and FPR1 were confirmed via the integrated matrix.Several potential biomarkers for AMI detection were identified, such as GZMB, GBP5, FPR1, TLR2, STAT1, and SPZ1. They might exert their functions via regulation of immune and inflammation responses. Genes in grey module play significant roles in AMI via regulation of macrophage activation.

Longitudinal IP-10 Serum Levels Are Associated with the Course of Disease Activity and Remission in Patients with Rheumatoid Arthritis

Although rheumatoid arthritis (RA) is a chronic, persistent autoimmune disease, 10 to 15% of RA patients achieve sustained disease-modifying antirheumatic drug (DMARD)-free remission over time. The biological mechanisms underlying the resolution of persistent inflammation in RA are still unidentified, and there is a lack of prognostic markers. It is well established that increased serum levels of gamma interferon-induced protein 10 (IP-10) are associated with (acute) increased inflammatory responses (e.g., in leprosy). In order to assess the potential of IP-10 as a diagnostic tool for inflammatory episodes of RA, we performed a retrospective study and assessed IP-10 levels in longitudinally banked serum samples obtained from patients upon first diagnosis of RA. The selection consisted of 15 persistent RA patients and 19 patients who achieved DMARD-free sustained remission. IP-10 levels, measured by use of a user-friendly quantitative lateral flow assay (LFA), showed up to 170-fold variation interindividually, and baseline IP-10 levels could not be differentiated between the two patient groups. However, a difference in the change in IP-10 levels between the first and last visits (ΔIP-10) was observed (P = 0.003) between DMARD-free (median ΔIP-10, -662 pg/ml [decrease]) and persistent (median ΔIP-10, 468 pg/ml [increase]) RA patients. Moreover, intraindividual changes in IP-10 levels during the course of disease corresponded to the disease activity score (DAS) (P = 0.05). These data indicate that IP-10 is associated with disease activity and perseverance of RA. The association of IP-10 with DAS indicates that this tool may be a practical diagnostic aid to help in monitoring disease progression in RA patients and may also find applications in other chronic diseases with exacerbated inflammatory episodes.

Identification of genetic determinants of breast cancer immune phenotypes by integrative genome-scale analysis

Cancer immunotherapy is revolutionizing the clinical management of several tumors, but has demonstrated limited activity in breast cancer. The development of more effective treatments is hindered by incomplete knowledge of the genetic determinant of immune responsiveness. To fill this gap, we mined copy number alteration, somatic mutation, and expression data from The Cancer Genome Atlas (TCGA). By using RNA-sequencing data from 1,004 breast cancers, we defined distinct immune phenotypes characterized by progressive expression of transcripts previously associated with immune-mediated rejection. The T helper 1 (Th-1) phenotype (ICR4), which also displays upregulation of immune-regulatory transcripts such as PDL1, PD1, FOXP3, IDO1, and CTLA4, was associated with prolonged patients' survival. We validated these findings in an independent meta-cohort of 1,954 breast cancer gene expression data. Chromosome segment 4q21, which includes genes encoding for the Th-1 chemokines CXCL9-11, was significantly amplified only in the immune favorable phenotype (ICR4). The mutation and neoantigen load progressively decreased from ICR4 to ICR1 but could not fully explain immune phenotypic differences. Mutations of TP53 were enriched in the immune favorable phenotype (ICR4). Conversely, the presence of MAP3K1 and MAP2K4 mutations were tightly associated with an immune-unfavorable phenotype (ICR1). Using both the TCGA and the validation dataset, the degree of MAPK deregulation segregates breast tumors according to their immune disposition. These findings suggest that mutation-driven perturbations of MAPK pathways are linked to the negative regulation of intratumoral immune response in breast cancer. Modulations of MAPK pathways could be experimentally tested to enhance breast cancer immune sensitivity.

Circulating IL-27 Is Elevated in Rheumatoid Arthritis Patients

Cytokines are key immunoregulatory molecules that regulate T lymphocyte-mediated immune responses and inflammatory reactions. We determined whether there is aberrant expression of interleukin-27 (IL-27) in rheumatoid arthritis (RA) patients and investigated the clinical significance of these changes. IL-27 is a key cellular factor that regulates the differentiation of CD4+ T cells, which can secrete interleukin-10 (IL-10) and interleukin-17 (IL-17) in vivo. Concentrations of serum IL-27 in 67 RA patients, and 36 sex- and age-matched control subjects were measured by enzyme-linked immunosorbent assay (ELISA). Results showed that concentrations of serum IL-27 in all RA patients were significantly higher than in healthy control subjects, and there was a significant and positive correlation between serum IL-27 levels and disease activity in all RA patients. Levels of serum IL-27 in RA patients were significantly correlated with disease activity score in 28 joints (DAS28). Moreover, immunosuppressive treatment with leflunomide downregulated the levels of IL-27 in active RA patients. Therefore, the elevated production of circulating T cell inflammatory factors contributes to the pathogenesis of RA, and serum IL-27 could potentially serve as a new biomarker of RA disease activity.

Increased chemotaxis and activity of circulatory myeloid progenitor cells may contribute to enhanced osteoclastogenesis and bone loss in the C57BL/6 mouse model of collagen-induced arthritis

Our study aimed to determine the functional activity of different osteoclast progenitor (OCP) subpopulations and signals important for their migration to bone lesions, causing local and systemic bone resorption during the course of collagen-induced arthritis in C57BL/6 mice. Arthritis was induced with chicken type II collagen (CII), and assessed by clinical scoring and detection of anti-CII antibodies. We observed decreased trabecular bone volume of axial and appendicular skeleton by histomorphometry and micro-computed tomography as well as decreased bone formation and increased bone resorption rate in arthritic mice in vivo. In the affected joints, bone loss was accompanied with severe osteitis and bone marrow hypercellularity, coinciding with the areas of active osteoclasts and bone erosions. Flow cytometry analysis showed increased frequency of putative OCP cells (CD3^- B220^- NK1.1^- CD11b^-/lo CD117⁺ CD115⁺ for bone marrow and CD3^- B220^- NK1.1^- CD11b⁺ CD115⁺ Gr-1⁺ for peripheral haematopoietic tissues), which exhibited enhanced differentiation potential in vitro. Moreover, the total CD11b⁺ population was expanded in arthritic mice as well as CD11b⁺ F4/80⁺ macrophage, CD11b⁺ NK1.1⁺ natural killer cell and CD11b⁺ CD11c⁺ myeloid dendritic cell populations in both bone marrow and peripheral blood. In addition, arthritic mice had increased expression of tumour necrosis factor-α, interleukin-6, CC chemokine ligand-2 (Ccl2) and Ccl5, with increased migration and differentiation of circulatory OCPs in response to CCL2 and, particularly, CCL5 signals. Our study characterized the frequency and functional properties of OCPs under inflammatory conditions associated with arthritis, which may help to clarify crucial molecular signals provided by immune cells to mediate systemically enhanced osteoresorption.

LncRNAs expression in adjuvant-induced arthritis rats reveals the potential role of LncRNAs contributing to rheumatoid arthritis pathogenesis

BACKGROUND

Long non-coding RNAs (LncRNAs) are an important class of widespread molecules involved in diverse biological functions, which are exceptionally expressed in numerous types of diseases. Currently, limited study on LncRNA in rheumatoid arthritis (RA) is available. In this study, we aimed to identify the specifically expressed LncRNA that are relevant to adjuvant-induced arthritis (AA) in rats, and to explore the possible molecular mechanisms of RA pathogenesis.

METHODS

To identify LncRNAs specifically expressed in rheumatoid arthritis, the expression of LncRNAs in synoviums of rats from the model group (n=3) was compared with that in the control group (n=3) using Arraystar Rat LncRNA/mRNA microarray and real-time polymerase chain reaction (RT-PCR).

RESULTS

Up to 260 LncRNAs were found to be differentially expressed (≥1.5-fold-change) in the synoviums between AA model and the normal rats (170 up-regulated and 90 down-regulated LncRNAs in AA rats compared with normal rats). Coding-non-coding gene co-expression networks (CNC network) were drawn based on the correlation analysis between the differentially expressed LncRNAs and mRNAs. Six LncRNAs, XR_008357, U75927, MRAK046251, XR_006457, DQ266363 and MRAK003448, were selected to analyze the relationship between LncRNAs and RA via the CNC network and GO analysis. Real-time PCR result confirmed that the six LncRNAs were specifically expressed in the AA rats.

CONCLUSIONS

These results revealed that clusters of LncRNAs were uniquely expressed in AA rats compared with controls, which manifests that these differentially expressed LncRNAs in AA rats might play a vital role in RA development. Up-regulation or down-regulation of the six LncRNAs might contribute to the molecular mechanism underlying RA. To sum up, our study provides potential targets for treatment of RA and novel profound understanding of the pathogenesis of RA.

Metal Ion Levels Are Not Correlated With Histopathology of Adverse Local Tissue Reactions in Taper Corrosion of Total Hip Arthroplasty

BACKGROUND

The underlying biological mechanism in the formation of adverse local tissue reaction in taper corrosion of total hip arthroplasty (THA) remains unknown. This study evaluated whether there was a dose-dependent relationship between metal ion levels, intraoperative tissue damage and ALVAL (aseptic lymphocyte-dominated vasculitis-associated lesion) scores in dual taper THA patients who underwent revisions for taper corrosion.

METHODS

We performed a retrospective review of 31 dual taper THA patients who underwent revision surgery from May 2013 to October 2013. Preoperative serum metal ion levels, intraoperative tissue damage grading, and ALVAL scores were reviewed. Multivariate analysis was performed to determine if an association existed between metal ion levels, intraoperative tissue damage, and ALVAL scores.

RESULTS

Findings consistent with adverse local tissue reaction were found in all cases. We noted 10 patients with low, 8 with moderate, and 13 with high ALVAL scores, respectively. For intraoperative tissue damage, we recorded 2 (grade 1), 22 (grade 2) and 7 (grade 3) cases. Preoperatively, there was preferential elevation of serum cobalt (3.8 ng/mL, 2.3-17.0) compared to serum chromium (1.0 ng/mL, 0.2-5.8). There was no correlation between preoperative metal ion levels and intraoperative tissue damage (R = -0.06, P = .74) or ALVAL scores (R = -0.04, P = .481). There was also no correlation between intraoperative tissue damage and ALVAL score (R = -0.06, P = .73).

CONCLUSION

There was no significant correlation between ALVAL scores and prerevision surgery metal ion levels or intraoperative tissue damage, suggesting that the biological mechanism of histologic morphology cannot be solely attributed to elevated metal ion levels and is likely multifactorial, reflecting a complex interplay between implant and patient factors.

Screening of gene signatures for rheumatoid arthritis and osteoarthritis based on bioinformatics analysis

The current study aimed to identify gene signatures during rheumatoid arthritis (RA) and osteoarthritis (OA), and used these to elucidate the underlying modular mechanisms. Using the Gene Expression Omnibus database, the present study obtained the GSE7669 mRNA expression microarray data from RA and OA synovial fibroblasts (n=6 each). The differentially expressed genes (DEGs) in RA synovial samples compared with OA samples were identified using the Linear Models for Microarray Analysis package. The Gene Ontology and Kyoto Encyclopedia of Genes and Genomes pathway enrichment analyses were performed using the Database for Annotation Visualization and Integrated Discovery. A protein‑protein interaction network was constructed and the modules were further analyzed using the Molecular Complex Detection plugin of Cytoscape. A total of 181 DEGs were identified by comparing RA and OA synovial samples (96 up‑ and 85 downregulated genes). The significant DEGs in module 1, including collagen, type I, α 1 (COL1A1), COL3A1, COL4A1 and COL11A1, were predominantly enriched in the extracellular matrix (ECM)‑receptor interaction and focal adhesion pathways. Additionally, significant DEGs in module 2, including radical S‑adenosyl methionine domain containing 2 (RSAD2), 2'‑5'‑oligoadenylate synthetase 2 (OAS2), myxovirus (influenza virus) resistance 1 (MX1) and ISG15 ubiquitin‑like modifier (ISG15), were predominantly associated with immune function pathways. In conclusion, the present study indicated that RSAD2, OAS2, MX1 and ISG15 may be notable gene signatures in RA development via regulation of the immune response. COL3A1, COL4A1, COL1A1 and COL11A1 may be important gene signatures in OA development via involvement in the pathways of ECM-receptor interactions and focal adhesions.

Histone deacetylase 3 regulates the inflammatory gene expression programme of rheumatoid arthritis fibroblast-like synoviocytes

Objectives

Non-selective histone deacetylase (HDAC) inhibitors (HDACi) have demonstrated anti-inflammatory properties in both in vitro and in vivo models of rheumatoid arthritis (RA). Here, we investigated the potential contribution of specific class I and class IIb HDACs to inflammatory gene expression in RA fibroblast-like synoviocytes (FLS).

Methods

RA FLS were incubated with pan-HDACi (ITF2357, givinostat) or selective HDAC1/2i, HDAC3/6i, HDAC6i and HDAC8i. Alternatively, FLS were transfected with HDAC3, HDAC6 or interferon (IFN)-α/β receptor alpha chain (IFNAR1) siRNA. mRNA expression of interleukin (IL)-1β-inducible genes was measured by quantitative PCR (qPCR) array and signalling pathway activation by immunoblotting and DNA-binding assays.

Results

HDAC3/6i, but not HDAC1/2i and HDAC8i, significantly suppressed the majority of IL-1β-inducible genes targeted by pan-HDACi in RA FLS. Silencing of HDAC3 expression reproduced the effects of HDAC3/6i on gene regulation, contrary to HDAC6-specific inhibition and HDAC6 silencing. Screening of the candidate signal transducers and activators of transcription (STAT)1 transcription factor revealed that HDAC3/6i abrogated STAT1 Tyr701 phosphorylation and DNA binding, but did not affect STAT1 acetylation. HDAC3 activity was required for type I IFN production and subsequent STAT1 activation in FLS. Suppression of type I IFN release by HDAC3/6i resulted in reduced expression of a subset of IFN-dependent genes, including the chemokines CXCL9 and CXCL11.

Conclusions

Inhibition of HDAC3 in RA FLS largely recapitulates the effects of pan-HDACi in suppressing inflammatory gene expression, including type I IFN production in RA FLS. Our results identify HDAC3 as a potential therapeutic target in the treatment of RA and type I IFN-driven autoimmune diseases.

Identification of miR-15b as a transformation-related factor in mantle cell lymphoma

Mantle cell lymphoma (MCL) is an aggressive B cell lymphoma with a poor prognosis. It is characterized by the t(11;14)(q13;q32) translocation, resulting in overexpression of CCND1. Morphologically, MCL is categorised into two types: classical MCL (cMCL) and aggressive MCL (aMCL), with a proportion of cMCL progressing to develop into aMCL. miRNAs are currently considered to be important regulators for cell behavior and are deregulated in many malignancies. Although several genetic alterations have been implicated in the transformation of cMCL to aMCL, the involvement of miRNAs in transformation is not known. In an effort to identify the miRNAs related to the transformation of MCL, miRNA microarray analyses were used for cMCL and aMCL cases. These analyses demonstrated significant differences in the expression of seven microRNAs based on a t-test (p-value <0.05); miR-15b was greatly upregulated in aMCL. Locked nucleic acid in situ hybridization showed increased staining of miR-15b in formalin-fixed paraffin-embedded sections of aMCL. These results correlated well with the microRNA microarray analysis. Although the molecular functions of miR-15b are largely unknown, it has been found to be associated with the cell cycle and apoptosis. However, the physiological significance of increased miR-15b in MCL is still unknown. Our present findings suggest that the upregulated expression of miR-15b is likely to play an important role in the transformation of cMCL to aMCL.

Peptide motif analysis predicts alphaviruses as triggers for rheumatoid arthritis

Rheumatoid arthritis (RA) develops in response to both genetic and environmental factors. The strongest genetic determinant is HLA-DR, where polymorphisms within the P4 and P6 binding pockets confer elevated risk. However, low disease concordance across monozygotic twin pairs underscores the importance of an environmental factor, probably infectious. The goal of this investigation was to predict the microorganism most likely to interact with HLA-DR to trigger RA under the molecular mimicry hypothesis. A set of 185 structural proteins from viruses or intracellular bacteria was scanned for regions of sequence homology with a collagen peptide that binds preferentially to DR4; candidates were then evaluated against a motif required for T cell cross-reactivity. The plausibility of the predicted agent was evaluated by comparison of microbial prevalence patterns to epidemiological characteristics of RA. Peptides from alphavirus capsid proteins provided the closest fit. Variations in the P6 position suggest that the HLA binding preference may vary by species, with Ross River virus, Chikungunya virus, and Mayaro virus peptides binding preferentially to DR4, and peptides from Sindbis/Ockelbo virus showing stronger affinity to DR1. The predicted HLA preference is supported by epidemiological studies of post-infection chronic arthralgia. Parallels between the cytokine profiles of RA and chronic alphavirus infection are discussed.

Adverse local tissue reaction (ALTR) associated with corrosion products in metal-on-metal and dual modular neck total hip replacements is associated with upregulation of interferon gamma-mediated chemokine signaling

Adverse local tissue reactions (ALTR) associated with tribocorrosion following total hip arthroplasty (THA) have become a significant clinical concern in recent years. In particular, implants featuring metal-on-metal bearing surfaces and modular femoral stems have been reported to result in elevated rates of ALTR. These tribocorrosion-related tissue reactions are characterized by marked necrosis and lymphocytic infiltration, which contrasts sharply with the macrophagic and foreign body giant cell inflammation associated with polyethylene wear particle induced peri-implant osteolysis. In this study, we characterize tribocorrosion-associated ALTR at a molecular level. Gene expression profiling of peri-implant tissue around failing implants identifies upregulation of numerous inflammatory mediators in ALTR, including several interferon gamma inducible factors, most notably the chemokines MIG/CXCL9 and IP-10/CXCL10. This expression profile is distinct from that associated with polyethylene wear induced osteolysis, which is characterized by induction of markers of alternative macrophage activation, such as chitotriosidase (CHIT-1). Importantly, MIG/CXCL9 and IP-10/CXCL10 are also elevated at the protein level in the synovial fluid and, albeit more moderately, the serum, of ALTR patients, raising the possibility that these factors may serve as circulating biomarkers for the early detection of ALTR in at-risk patients.

A distinct pre-existing inflammatory tumour microenvironment is associated with chemotherapy resistance in high-grade serous epithelial ovarian cancer

Background:

Chemotherapy resistance is a major determinant of poor overall survival rates in high-grade serous ovarian cancer (HGSC). We have previously shown that gene expression alterations affecting the NF-κB pathway characterise chemotherapy resistance in HGSC, suggesting that the regulation of an immune response may be associated with this phenotype.

Methods:

Given that intrinsic drug resistance pre-exists and is governed by both tumour and host factors, the current study was performed to examine the cross-talk between tumour inflammatory microenvironment and cancer cells, and their roles in mediating differential chemotherapy response in HGSC patients. Expression profiling of a panel of 184 inflammation-related genes was performed in 15 chemoresistant and 19 chemosensitive HGSC tumours using the NanoString nCounter platform.

Results:

A total of 11 significantly differentially expressed genes were found to distinguish the two groups. As STAT1 was the most significantly differentially expressed gene (P=0.003), we validated the expression of STAT1 protein by immunohistochemistry using an independent cohort of 183 (52 resistant and 131 sensitive) HGSC cases on a primary tumour tissue microarray. Relative expression levels were subjected to Kaplan–Meier survival analysis and Cox proportional hazard regression models.

Conclusions:

This study confirms that higher STAT1 expression is significantly associated with increased progression-free survival and that this protein together with other mediators of tumour–host microenvironment can be applied as a novel response predictive biomarker in HGSC. Furthermore, an overall underactive immune microenvironment suggests that the pre-existing state of the tumour immune microenvironment could determine response to chemotherapy in HGSC.

CXCL9 and CXCL10 gene polymorphisms in patients with rheumatoid arthritis

Chemokines (CXCL) and their receptors play important roles in the pathogenesis of rheumatoid arthritis (RA). The aim of this study was to examine the associations between polymorphisms in the CXCL9 (rs3733236 G>A) and CXCL10 (rs8878 A>G) genes and RA. We examined 422 RA patients and 338 subjects as a control group. Single nucleotide polymorphisms (SNPs) in the CXCL9 (rs3733236 G>A) and CXCL10 (rs8878 A>G) genes were genotyped using TaqMan genotyping assays from Life Technologies Genomic. There were no significant differences in distribution of CXCL9 genotypes and alleles between RA patients and control group. Among RA patients, the increased frequency of CXCL10 (rs8878) G allele carriers was detected AG+GG vs AA (p = 0.034; OR 1.49, 95 % CI 1.03-2.13). There were no significant associations of CXCL9 genotypes with age of disease diagnosis rheumatoid factor, erosive disease, and extra-articular manifestations. In case of CXCL10 genotypes, there was the increased frequency of extra-articular manifestations in GG genotype carriers GG vs AA+AG (p = 0.027; OR 1.82, 95 % CI 1.09-3.03). In the multivariate regression analysis, the CXCL10 GG genotype was the independent factor associated with increased probability of extra-articular manifestations development (p = 0.034; OR 1.75, 95 % CI 1.04-3.03). The results of this study suggest the association between CXCL10 gene polymorphism and rheumatoid arthritis.

Orphan nuclear receptor NR4A2 induces transcription of the immunomodulatory peptide hormone prolactin

Background

Nuclear receptor 4A2 (NR4A2) is an orphan nuclear receptor and constitutively active transcription factor expressed at elevated levels in inflamed joint tissues from patients with arthritis. Inflammatory mediators rapidly and potently induce NR4A2 expression in resident joint cells and infiltrating immune cells. This receptor promotes synovial hyperplasia by increasing proliferation of synoviocytes and inducing transcription of matrix degrading enzymes and pro-inflammatory mediators. In order to further elucidate the molecular mechanisms of NR4A2, we conducted a gene expression screen to identify novel transcriptional targets of NR4A2 that may contribute to arthritis progression.

Methods

NR4A2 was over-expressed in human synoviocytes by lentiviral transduction and gene expression changes were measured using qPCR arrays specific for inflammation, proliferation, adhesion, and migration pathways. Subsequent analysis focused on the most potently induced gene prolactin (PRL). Messenger RNA levels of PRL and PRL receptor (PRL-R) were measured by RT-qPCR and protein levels were measured by ELISA. PRL promoter studies were conducted in synoviocytes transiently transfected with NR4A2 and PRL reporter constructs. Molecular responses to PRL in synoviocytes were addressed using qPCR arrays specific for JAK/STAT signaling pathways.

Results

PRL was the most potently induced gene on the qPCR arrays, exhibiting a 68-fold increase in response to ectopic NR4A2. This gene encodes an immunomodulatory peptide hormone with roles in autoimmune diseases and inflammation. Induction of PRL mRNA and secreted protein by NR4A2 was confirmed in subsequent experiments, with increases of 300-fold and 18-fold respectively. Depletion of endogenous NR4A receptors with shRNA reduced basal and PGE₂-induced PRL levels by 95%. At the transcriptional level, NR4A2 requires a functional DNA binding domain to transactivate the distal PRL promoter. Deletional analysis indicates that NR4A2 targets a region of the distal PRL promoter spanning −270 to -32 bp. In synoviocytes, recombinant PRL regulates several genes involved in inflammation, proliferation, and cell survival, suggesting that NR4A2 induced PRL may also impact these pathways and contribute to arthritis progression.

Conclusions

These results provide the first evidence for transcriptional regulation of the immunomodulatory peptide hormone PRL by NR4A2 in synoviocytes, and highlight a novel molecular pathway in inflammatory arthritis.

Electronic supplementary material

The online version of this article (doi:10.1186/s12950-015-0059-2) contains supplementary material, which is available to authorized users.