Rheumatoid Tissue Research Articles

Bioinformatics analysis of rheumatoid arthritis tissues identifies genes and potential drugs that are expressed specifically

Studies have implicated necroptosis mechanisms in orthopaedic-related diseases, since necroptosis is a unique regulatory cell death pattern. However, the role of Necroptosis-related genes in rheumatoid arthritis (RA) has not been well described. We downloaded RA-related data information and Necroptosis-related genes from the Gene Expression Omnibus (GEO), Kyoto Gene and Genome Encyclopedia (KEGG) database, and Genome Enrichment Analysis (GSEA), respectively. We identified 113 genes associated with RA-related necroptosis, which was closely associated with the cytokine-mediated signaling pathway, necroptosis and programmed necrosis. Subsequently, FAS, MAPK8 and TNFSF10 were identified as key genes among 48 Necroptosis-associated differential genes by three machine learning algorithms (LASSO, RF and SVM-RFE), and the key genes had good diagnostic power in distinguishing RA patients from healthy controls. According to functional enrichment analysis, these genes may regulate multiple pathways, such as B-cell receptor signaling, T-cell receptor signaling pathways, chemokine signaling pathways and cytokine-cytokine receptor interactions, and play corresponding roles in RA. Furthermore, we predicted 48 targeted drugs against key genes and 31 chemical structural formulae based on targeted drug prediction. Moreover, key genes were associated with complex regulatory relationships in the ceRNA network. According to CIBERSORT analysis, FAS, MAPK8 and TNFSF10 may be associated with changes in the immune microenvironment of RA patients. Our study developed a diagnostic validity and provided insight to the mechanisms of RA. Further studies will be required to test its diagnostic value for RA before it can be implemented in clinical practice.

A novel IRAK4/PIM1 inhibitor ameliorates rheumatoid arthritis and lymphoid malignancy by blocking the TLR/MYD88-mediated NF-κB pathway.

Interleukin-1 receptor-associated kinase 4 (IRAK4) is a pivotal enzyme in the Toll-like receptor (TLR)/MYD88 dependent signaling pathway, which is highly activated in rheumatoid arthritis tissues and activated B cell-like diffuse large B-cell lymphoma (ABC-DLBCL). Inflammatory responses followed by IRAK4 activation promote B-cell proliferation and aggressiveness of lymphoma. Moreover, proviral integration site for Moloney murine leukemia virus 1 (PIM1) functions as an anti-apoptotic kinase in propagation of ABC-DLBCL with ibrutinib resistance. We developed a dual IRAK4/PIM1 inhibitor KIC-0101 that potently suppresses the NF-κB pathway and proinflammatory cytokine induction invitro and invivo. In rheumatoid arthritis mouse models, treatment with KIC-0101 significantly ameliorated cartilage damage and inflammation. KIC-0101 inhibited the nuclear translocation of NF-κB and activation of JAK/STAT pathway in ABC-DLBCLs. In addition, KIC-0101 exhibited an anti-tumor effect on ibrutinib-resistant cells by synergistic dual suppression of TLR/MYD88-mediated NF-κB pathway and PIM1 kinase. Our results suggest that KIC-0101 is a promising drug candidate for autoimmune diseases and ibrutinib-resistant B-cell lymphomas.

Amphiphilic Myopathy Induced by Hydroxychloroquine Presenting with Dysarthria

Chloroquine and hydroxychloroquine (HCQ) are commonly used antimalarial agents as the treatment for a wide range of autoimmune disorders including dermatological, rheumatoid, and connective tissue diseases. These amphiphilic drugs can cause toxic myopathy in in patients which are commonly characterized as reversible proximal muscle weakness, dysphagia and dyspnea. Herein, we report a case of a patient on HCQ, who suffered from toxic myopathy presenting as proximal muscle weakness and dysarthria, which was fully recovered after the cessation.

Mitochondrial aspartate regulates TNF biogenesis and autoimmune tissue inflammation.

Misdirected immunity gives rise to the autoimmune tissue inflammation of rheumatoid arthritis, in which excess production of the cytokine tumor necrosis factor (TNF) is a central pathogenic event. Mechanisms underlying the breakdown of self-tolerance are unclear, but T cells in the arthritic joint have a distinctive metabolic signature of ATPlo acetyl-CoAhi proinflammatory effector cells. Here we show that a deficiency in the production of mitochondrial aspartate is an important abnormality in these autoimmune T cells. Shortage of mitochondrial aspartate disrupted the regeneration of the metabolic cofactor nicotinamide adenine dinucleotide, causing ADP deribosylation of the endoplasmic reticulum (ER) sensor GRP78/BiP. As a result, ribosome-rich ER membranes expanded, promoting co-translational translocation and enhanced biogenesis of transmembrane TNF. ERrich T cells were the predominant TNF producers in the arthritic joint. Transfer of intact mitochondria into T cells, as well as supplementation of exogenous aspartate, rescued the mitochondria-instructed expansion of ER membranes and suppressed TNF release and rheumatoid tissue inflammation.

Arthritis flares mediated by tissue-resident memory Tcells in the joint.

Rheumatoid arthritis is a systemic autoimmune disease, but disease flares typically affect only a subset of joints, distributed in a distinctive pattern for each patient. Pursuing this intriguing pattern, we show that arthritis recurrence is mediated by long-lived synovial resident memory Tcells (TRM). In three murine models, CD8+ cells bearing TRM markers remain in previously inflamed joints during remission. These cells are bona fide TRM, exhibiting a failure to migrate between joints, preferential uptake of fatty acids, and long-term residency. Disease flares result from TRM activation by antigen, leading to CCL5-mediated recruitment of circulating effector cells. Correspondingly, TRM depletion ameliorates recurrence in a site-specific manner. Human rheumatoid arthritis joint tissues contain a comparable CD8+-predominant TRM population, which is most evident in late-stage leukocyte-poor synovium, exhibiting limited Tcell receptor diversity and a pro-inflammatory transcriptomic signature. Together, these findings establish synovial TRM as a targetable mediator of disease chronicity in autoimmune arthritis.

Pulmonary rehabilitation in patients with interstitial lung disease associated with rheumatoid arthritis or connective tissue disease: From mechanisms to practice

Interstitial lung diseases are a large group of lung conditions characterized by inflammation and fibrosis. Interstitial lung disease in connective tissue diseases and rheumatoid arthritis is a severe complication of these pathologies. Apart from the pharmacological treatment, exercise training could help reduce breathing difficulties and increase physical strength, lower the burden of disease, help improving self-esteem and fight against depression and anxiety. Exercise training can be done either alone, or enhanced by auxiliary methods like oxygen administration, neuromuscular electrical stimulation or improving the strength of respiratory muscles. Possible associated lung diseases should be always taken into account. Even if exercise training is generally considered safe for this category of patients, there are also risks like exercise-induced hypoxemia, arrhythmia or pulmonary hypertension. Exercise training in this setting should be performed by dedicated physiotherapists after specialist prescription and under surveillance in a safe environment.

Circulating and Synovial Pentraxin-3 (PTX3) Expression Levels Correlate With Rheumatoid Arthritis Severity and Tissue Infiltration Independently of Conventional Treatments Response.

AimsTo determine the relationship between PTX3 systemic and synovial levels and the clinical features of rheumatoid arthritis (RA) in a cohort of early, treatment naïve patients and to explore the relevance of PTX3 expression in predicting response to conventional-synthetic (cs) Disease-Modifying-Anti-Rheumatic-Drugs (DMARDs) treatment.MethodsPTX3 expression was analyzed in 119 baseline serum samples from early naïve RA patients, 95 paired samples obtained 6-months following the initiation of cs-DMARDs treatment and 43 healthy donors. RNA-sequencing analysis and immunohistochemistry for PTX3 were performed on a subpopulation of 79 and 58 synovial samples, respectively, to assess PTX3 gene and protein expression. Immunofluorescence staining was performed to characterize PTX3 expressing cells within the synovium.ResultsCirculating levels of PTX3 were significantly higher in early RA compared to healthy donors and correlated with disease activity at baseline and with the degree of structural damages at 12-months. Six-months after commencing cs-DMARDs, a high level of PTX3, proportional to the baseline value, was still detectable in the serum of patients, regardless of their response status. RNA-seq analysis confirmed that synovial transcript levels of PTX3 correlated with disease activity and the presence of mediators of inflammation, tissue remodeling and bone destruction at baseline. PTX3 expression in the synovium was strongly linked to the degree of immune cell infiltration, the presence of ectopic lymphoid structures and seropositivity for autoantibodies. Accordingly, PTX3 was found to be expressed by numerous synovial cell types such as plasma cells, fibroblasts, vascular and lymphatic endothelial cells, macrophages, and neutrophils. The percentage of PTX3-positive synovial cells, although significantly reduced at 6-months post-treatment as a result of global decreased cellularity, was similar in cs-DMARDs responders and non-responders.ConclusionThis study demonstrates that, early in the disease and prior to treatment modification, the level of circulating PTX3 is a reliable marker of RA activity and predicts a high degree of structural damages at 12-months. In the joint, PTX3 associates with immune cell infiltration and the presence of ectopic lymphoid structures. High synovial and peripheral blood levels of PTX3 are associated with chronic inflammation characteristic of RA. Additional studies to determine the mechanistic link are required.

Value of serum collagen triple helix repeat containing-1(CTHRC1) and 14-3-3η protein compared to anti-CCP antibodies and anti-MCV antibodies in the diagnosis of rheumatoid arthritis

ABSTRACT Introduction Serological markers are important in the diagnosis of rheumatoid arthritis (RA) and other connective tissues diseases This study explored the clinical value of collagen triple helix repeat containing-1 (CTHRC1) and 14-3-3η protein, compared to routine markers, in the diagnosis of RA. Methods We recruited 103 RA patients, 105 non-RA patients (osteoarthritis, ankylosing spondylitis, systemic lupus erythematosus) and 59 healthy controls. CTHRC1, 14-3-3η, anti-cyclic citrullinated peptide antibody (anti-CCP), anti-mutated citrullinated vimentin antibody (anti-MCV), rheumatoid factor and erythrocyte sedimentation rate (ESR) levels were measured, and their diagnostic value for RA evaluated and compared. Results All laboratory indices were elevated in RA (P < 0.05). Of these, anti-MCV had the highest sensitivity (86.4%) and anti-CCP the highest specificity (94.5%). The areas under the curve (AUC) of CTHRC1, 14-3-3η, anti-CCP, anti-MCV, rheumatoid factor and ESR were 0.84, 0.81, 0.89, 0.91, 0.85 and 0.77 respectively (all P < 0.01). Anti-CCP and anti-MCV were the most valuable in the diagnosis of RA. The combination of anti-CCP and anti-MCV had the maximum Youden index, followed by the combination of anti-CCP and 14-3-3η. Binary logistic regression analysis showed that 14-3-3η had the largest odds ratio value (95% CI) at 5.1 (2.1–12.5) for RA. Conclusion CTHRC1 and 14-3-3η are promising serological indicators of RA, and when combined with anti-CCP, anti-MCV and ESR, can improve the diagnosis of this disease.

RB137 recognizes LL37 in neutrophil-extracellular trap-like (NET) structures in systemic lupus erythematosus and rheumatoid arthritis inflamed tissues by immunofluorescence in histological sections

Besides being a natural antibiotic, the human cathelicidin LL37, produced by epithelial cells and neutrophils, is an important immune-modulator. LL37 alone, or in complex with DNA, can activate inflammatory pathways in psoriasis, Systemic Lupus Erythematosus (SLE) and Rheumatoid Arthritis (RA). In this work, we describe the capacity of the recombinant monoclonal antibody RB137, previously shown to specifically recognize LL37 in its native form by ELISA, to detect LL37 by immunofluorescence in human tissues derived from SLE and RA patients. In these tissues, LL37 decorates DNA filaments resembling neutrophil-extracellular-trap (NET) structures. This antibody represents a valuable tool to detect the presence, the native state and the exact localization of LL37 in human tissues in health and disease.

Inhibition of miR-5571-3p Attenuates Proliferation and Invasion in Rheumatoid Arthritis Fibroblast-like Synoviocytes by Upregulating OAZ3

The aim of the present study was to explore the role and potential mechanism of miR-5571-3p in rheumatoid arthritis. In this study, miR-5571-3p level in rheumatoid arthritis tissues and fibroblast-like synoviocytes was detected using qRT-PCR analysis. Cell Counting Kit-8 assay was performed to determine proliferation of fibroblast-like synoviocyte. Transwell assay was conducted to examine the invasion of fibroblast-like synoviocytes, and western blot analysis was used to examine the ornithine decarboxylase antizyme 3 protein expression. Results showed that miR-5571-3p expression was elevated in vivo and in vitro in rheumatoid arthritis. Inhibition of miR-5571-3p suppressed rheumatoid arthritis fibroblastlike synoviocyte proliferation and invasion. ornithine decarboxylase antizyme 3 siRNA could partially abolish the suppressor effect of miR-5571-3p inhibitor in cell proliferation and invasion in fibroblastlike synoviocytes. In conclusion, miR-5571-3p and ornithine decarboxylase antizyme 3 played important regulatory roles in proliferation and invasion of rheumatoid arthritis fibroblast-like synoviocytes, miR5571-3p/ornithine decarboxylase antizyme 3 axis could serve as a new target for therapy of rheumatoid arthritis.

Senescent synovial fibroblasts accumulate prematurely in rheumatoid arthritis tissues and display an enhanced inflammatory phenotype

BackgroundAccumulation of senescent cells has been associated with pro-inflammatory effects with deleterious consequences in different human diseases. The purpose of this study was to analyze cell senescence in human synovial tissues (ST), and its impact on the pro-inflammatory function of synovial fibroblasts (SF).ResultsThe expression of the senescence marker p16INK4a (p16) was analyzed by immunohistochemistry in rheumatoid arthritis (RA), osteoarthritis (OA), and normal ST from variably aged donors. The proportion of p16(+) senescent cells in normal ST from older donors was higher than from younger ones. Although older RA and OA ST showed proportions of senescent cells similar to older normal ST, senescence was increased in younger RA ST compared to age-matched normal ST. The percentage of senescent SA-β-gal(+) SF after 14 days in culture positively correlated with donor’s age. Initial exposure to H2O2 or TNFα enhanced SF senescence and increased mRNA expression of IL6, CXCL8, CCL2 and MMP3 and proteins secretion. Senescent SF show a heightened IL6, CXCL8 and MMP3 mRNA and IL-6 and IL-8 protein expression response upon further challenge with TNFα. Treatment of senescent SF with the senolytic drug fenofibrate normalized IL6, CXCL8 and CCL2 mRNA expression.ConclusionsAccumulation of senescent cells in ST increases in normal aging and prematurely in RA patients. Senescence of cultured SF is accelerated upon exposure to TNFα or oxidative stress and may contribute to the pathogenesis of synovitis by increasing the production of pro-inflammatory mediators.

Imatinib inhibits CSF1R that stimulates proliferation of rheumatoid arthritis fibroblast-like synoviocytes.

In this study, we aimed to explore the effects of imatinib on the proliferation of rheumatoid arthritis synovial cell (RA-FLS) and inflammatory responses by regulating CSF1R. Differential genes were screened via microarray analysis, followed by being analysed through the weighted co-expression network (WGCNA) network, that included module and cluster analysis. The relationship between imatinib and genes was visualized using the Search Tool for the Retrieval of Interacting Genes (STITCH) database. Expressions of mRNA and protein were determined by reverse transcription-polymerase chain reaction (RT-PCR) and Western blot, respectively. Cell viability was examined via clone formation assay, while cell cycle and apoptosis were analysed through flow cytometry analysis. The hub gene CSF1R was ultimately determined by microarray analysis and WGCNA analysis. Colony-stimulating-factor receptor-1 (SF1R) was highly expressed in rheumatoid arthritis tissues and cells, and CSF1R over-expression could promote inflammatory responses. Moreover, CSF1R could promote RA-FLS proliferation, inhibit apoptosis and accelerate the cell cycle. The targeting relationship between imatinib and CSF1R was also validated in this study. Imatinib attenuated RA-FLS inflammation in a concentration-dependent manner. Meanwhile, imatinib could inhibit RA-FLS proliferation and promote apoptosis, ultimately reducing the damage of RA-FLS. Over-expression of CSF1R accelerated the cell cycle and proliferation of RA-FLS, while inhibiting cell apoptosis. Conversely, imatinib could significantly restrain the cell cycle and viability of RA-FLS and accelerated apoptosis via suppression of CSF1R expression. Further, histological and serological assay investigated and proved the proinflammatory effects of CSF1R in RA rabbits.

Differences in clinical Pneumocystis pneumonia in rheumatoid arthritis and other connective tissue diseases suggesting a rheumatoid-specific interstitial lung injury spectrum.

To compare Pneumocystis pneumonia (PCP) in patients with rheumatoid arthritis (RA) with PCP in patients with non-RA connective tissue diseases (CTDs) in order to clarify the characteristics of the former. We extracted consecutive patients satisfying the following criteria for "clinical PCP": (1) positive plasma β-D-glucan, (2) PCP-compatible computed tomography findings of the lung, and (3) successful treatment with antipneumocystic antibiotics. Patients who underwent methylprednisolone "pulse" therapy or sufficient antibiotics to cure bacterial pneumonia were excluded. We used the t test, U test, or Fischer's exact probability test to compare the two groups and Jonckheere-Terpstra's test and Ryan's procedure for the trend test. Thirty-five cases were extracted. The underlying rheumatic diseases were RA in 25 and non-RA CTDs in ten. At the onset of clinical PCP, the lymphocyte counts were 884 vs 357/mm3 (p < 0.001), PC-PCR positivity 64% vs 100% (p = 0.029), glucocorticoid dose 4.0 vs 17.5mg PSL/day (p < 0.001), and methotrexate dose 8 vs 0mg/week (p = 0.003). The PC-PCR-negative patients, observed only in the RA group, were all receiving methotrexate (MTX) therapy except one patient who was receiving high-dose prednisolone alone. All PC-PCR-positive patients were receiving glucocorticoid, TNF inhibitor, or a non-MTX immunosuppressant. No patient with MTX alone had positive PC-PCR results. Clinical PCP in RA patients differed from that in non-RA CTD patients and may be understood as only a part of the rheumatoid-specific interstitial lung injury spectrum influenced by multiple, synergistic factors including MTX, Pneumocystis, and RA itself.

Novel Anti-Inflammatory Peptides Based on Chemokine-Glycosaminoglycan Interactions Reduce Leukocyte Migration and Disease Severity in a Model of Rheumatoid Arthritis.

Inflammation is characterized by the infiltration of leukocytes from the circulation and into the inflamed area. Leukocytes are guided throughout this process by chemokines. These are basic proteins that interact with leukocytes to initiate their activation and extravasation via chemokine receptors. This is enabled through chemokine immobilization by glycosaminoglycans (GAGs) at the luminal endothelial surface of blood vessels. A specific stretch of basic amino acids on the chemokine, often at the C terminus, interacts with the negatively charged GAGs, which is considered an essential interaction for the chemokine function. Short-chain peptides based on this GAG-binding region of the chemokines CCL5, CXCL8, and CXCL12γ were synthesized using standard Fmoc chemistry. These peptides were found to bind to GAGs with high affinity, which translated into a reduction of leukocyte migration across a cultured human endothelial monolayer in response to chemokines. The leukocyte migration was inhibited upon removal of heparan sulfate from the endothelial surface and was found to reduce the ability of the chemokine and peptide to bind to endothelial cells in binding assays and to human rheumatoid arthritis tissue. The data suggest that the peptide competes with the wild-type chemokine for binding to GAGs such as HS and thereby reduces chemokine presentation and subsequent leukocyte migration. Furthermore, the lead peptide based on CXCL8 could reduce the disease severity and serum levels of the proinflammatory cytokine TNF-α in a murine Ag-induced arthritis model. Taken together, evidence is provided for interfering with the chemokine-GAG interaction as a relevant therapeutic approach.

Articular and subcutaneous adipose tissues of rheumatoid arthritis patients represent equal sources of immunoregulatory mesenchymal stem cells

Adipose-derived mesenchymal stem cells (ASCs) have immunoregulatory properties, but their activity is dependent on signals provided by the local microenvironment. It is likely that highly inflammatory milieu of rheumatoid joint affects ASCs activity. To test this hypothesis, the function of rheumatoid ASCs derived from articular adipose tissue (AT-ASCs) and ASCs derived from subcutaneous adipose tissue (Sc-ASCs) has been analysed. Articular adipose tissue (infrapatellar fat pad) and subcutaneous adipose tissue (from the site of skin closure with sutures) were obtained from rheumatoid arthritis (RA) patients undergoing total knee joint replacement surgery. ASCs were isolated accordingly to the routinely applied procedure, expanded and treated or not with IFNγ and TNF (10 ng/ml). To evaluate immunomodulatory properties of AT- and Sc-ASCs, co-cultures with peripheral blood mononuclear cells (PBMCs) from healthy donors have been set. Proliferation of activated PBMCs (3H-thymidine incorporation method), secretion of IL-10 and IL-17A in co-culture supernatants (specific ELISA tests) and T regulatory FoxP3+ cells (Tregs) percentage have been evaluated (flow cytometry). Performed experiments demonstrated that ASCs from both sources have comparable properties. They suppress proliferation of activated PBMCs to the similar extent, induce IL-10 secretion by resting PBMCs and moderately induce generation of FoxP3+ Treg cells. Interestingly, both AT-ASCs and Sc-ASCs cause increase of IL-17A secretion by activated PBMCs as well as induce up-regulation of IL-6 concentration in co-culture supernatants. We demonstrated that AT-ASCs and Sc-ASCs obtained from RA patients possess similar immunomodulatory properties despite different localization and distinct cytokine milieu of tissue of origin. Our results indicate that ASCs derived from rheumatoid adipose tissues are not strongly immunosuppressive in vitro and that they may contribute to the pathogenesis of RA due to IL-17A secretion enhancement.

MiR-338-5p Promotes Inflammatory Response of Fibroblast-Like Synoviocytes in Rheumatoid Arthritis via Targeting SPRY1.

Our purpose is to study the roles of microRNA-338-5p (miR-338-5p) on the proliferation, invasion, and inflammatory response of fibroblast-like synoviocytes (SFs) in rheumatoid arthritis patients by regulating SPRY1. The target relationship between miR-338-5p and SPRY1 was validated through luciferase reporter system. The expression of miR-338-5p and SPRY1 in synovial tissues and synovial cells were detected using RT-PCR and western blot. The mimics and inhibitors of miR-338-5p were transfected into SFs. MTT, Transwell, and ELISA assays were used to analyze cell proliferation, invasiveness, and the secreted extracellular pro-inflammatory cytokines (such as IL-1a, IL-6, COX2) levels of SFs. MiR-338-5p was highly expressed in rheumatoid arthritis tissues and cells, and directly down-regulated the expression of SPRY1 in the SFs of rheumatoid arthritis patients. Cell proliferation, invasiveness and the expression level of pro-inflammatory cytokines in synovial cells increased after the transfection of miR-338-5p mimics, while the proliferation, invasion and expression level of pro-inflammatory cytokines decreased after the transfection of miR-338-5p inhibitors. In conclusion,miR-338-5p promoted the proliferation, invasion and inflammatory reaction in SFs of rheumatoid arthritis by directly down-regulating SPRY1 expression. J. Cell. Biochem. 118: 2295-2301, 2017. © 2017 Wiley Periodicals, Inc.

ANALYSIS OF THE INCIDENCE OF RHEUMATIC DISEASES IN THE ARKHANGELSK REGION: TRENDS IN THE 2010–2015 STATISTICAL CHARACTERISTICS

Objective : to investigate the incidence of acute rheumatic fever (ARF), chronic rheumatic heart disease (CRHD), musculoskeletal diseases (MSD), and connective tissue diseases in the pediatric and adult populations of the Arkhangelsk Region (AR) in comparison with the data on Russia and the North-Western Federal District (NWFD) in 2010–2015. Subjects and methods. The total and primary incidence rates of ARF, CRHD, and MSD were analyzed in the pediatric and adult populations of these regions in 2010–2015. Results and discussion. Among the adult population of AR, the total incidence of ARF was low (7 cases in 2010 and none in 2015), which is comparable with the data in the whole of Russia. No recurrences of ARF were registered in the AR. Among the adult population of AR, the total incidence of CRHD fell by 28% in 2010 to 2015. The similar trend was also observed in the whole of Russia. Patients newly diagnosed with CRHD decreased by 65% in the AR. There was a 14% increase in the total incidence of MSD among the adult population of AR and an 11% decrease in its primary incidence. Since 2010, the total incidence of rheumatoid arthritis (RA), osteoarthritis, spondylopathies (SP), osteoporosis (OP), and systemic connective tissue diseases rose in the AR. There were 22 and 140% increases in the incidence of RA and SP, respectively; the number of reactive arthritis cases decreased by 17.2% in the adults and increased by 7% in the children. This trend in the adults is seen of the whole of Russia (an 8% decrease), although the latter in the AR is not comparable to the All-Russian measures. In the AR, the incidence of OP remains low (50 and 73 per 100,000 population in 2010 and 2015, respectively); this is noted to increase by 46% in the past 5 years; the similar trend was observed in both the whole of Russia and NWFD (7.8 and 8.3%, respectively).

Increased autophagy in fibroblast-like synoviocytes leads to immune enhancement potential in rheumatoid arthritis.

The incidence of rheumatoid arthritis (RA) has been reported to be correlated with a disorder of immunregulation. Rheumatoid arthritis fibroblast-like synoviocytes (RA-FLSs) play an important role in regulating the local immune microenvironment. However, the potential mechanism of RA-FLS in regulating the immnue response is not clearly understood. In this study, we demonstrated that the expression of HIF-1α was significantly up-regulated in rheumatoid arthritis tissue which indicated that the hypoxia condition in the microenvironment. We also observed that RA-FLSs demonstrated the potential to up-regulate immune activation. Meanwhile, the level of autophagy increased in RA-FLSs compared with control group. Besides that, the expression of IL-6 was up-regulated not only in RA-FLSs but also in the fibroblasts that treated with hypoxia condition. Accordingly, we found that autophagy inhibitiors could effectively inhibit the immune activation function of RA-FLSs medicated by IL-6. Taken together, the results we demonstrated above indicated that the hypoxia microenvironment could effectively induce the incidence of autophagy and then lead to the immune activation function of RA-FLSs medicated by IL-6.

Rheumatoid arthritis antigens homocitrulline and citrulline are generated by local myeloperoxidase and peptidyl arginine deiminases 2, 3 and 4 in rheumatoid nodule and synovial tissue.

BackgroundSeropositive rheumatoid arthritis (RA) is characterized by autoantibodies binding to citrullinated and homocitrullinated proteins. We wanted to study the expression patterns of these disease-associated protein forms and if the rheumatoid nodule and synovial tissue itself contain biologically active levels of citrullinating peptidyl arginine deiminases 2, 3 and 4 and homocitrullination-facilitating neutrophil enzyme myeloperoxidase.MethodTotal of 195 synovial samples from metatarsal joints from five ACPA/RF-positive RA patients (n = 77), synovial samples from knees of eight seropositive RA (n = 60), seven seronegative RA (n = 33) and five osteoarthritis (n = 25) patients were analyzed for citrulline and homocitrulline contents using HPLC. The location of citrulline- and homocitrulline-containing proteins, PAD 2, 3, 4 and myeloperoxidase were shown by immunostaining. Myeloperoxidase and citrulline- or homocitrulline-containing proteins were stained on Western blot.ResultsOverall, necrosis was frequent in metatarsals of seropositive RA and absent in seronegative RA and osteoarthritis patients. In histological analysis, there was a significant local patterning and variation in the citrulline and homocitrulline content and it was highest in metatarsal synovial tissues of seropositive RA patients. We found peptidyl arginine deiminase 2, 3 and 4 in the lining and sublining layers of intact synovial tissue. Myeloperoxidase was found locally around necrotic areas. The tissues with necrosis contained the highest levels of citrulline and homocitrulline.ConclusionsRheumatoid nodules and synovia contain significant amount of PAD2, 3 and 4 and myeloperoxidase enzymes. These enzymes could explain the levels of citrulline and homocitrulline in seropositive RA synovial and rheumatoid nodule tissues especially around necrotic tissue.

Pharmaceutical potential of tacrolimus-loaded albumin nanoparticles having targetability to rheumatoid arthritis tissues

Albumin is considered an attractive dug carrier for hydrophobic drugs to target inflamed joints of rheumatoid arthritis. This study focused on the pharmaceutical potential of albumin-based nanoparticles (NPs) on delivery of tacrolimus (TAC) to enhance targetability and anti-arthritic efficacy. TAC-loaded human serum albumin (HSA) nanoparticles (TAC HSA-NPs) were prepared using the nab™ technology. The resulting NPs were 185.8±6.8nm in diameter and had a zeta potential value of −30.5±1.1mV, as determined by dynamic light scattering. Particles were uniformly spherical in shape as determined by transmission electron microscopy. The encapsulation efficacy of TAC was 79.3±3.7% and the water solubility was over 46 times greater than that of free TAC. TAC was gradually released from NPs over 24h, which is sufficient time for targeting and treatment of the NPs in inflamed arthritis via intravenous injection. In vitro study using splenocytes excised from spleens of mice following induction of arthritis using collagen clearly demonstrated the anti-proliferative activity of TAC HSA-NPs on activated T cells compared with non-activated T cells. Furthermore, TAC HSA-NPs displayed significantly more anti-arthritic activity than TAC formulations including intravenously administered TAC solution or oral TAC suspension, as reflected by the incidence of arthritis and clinical score (1.6 vs. 3.2 and 5.0, respectively). These improvements were due to the targetability of HSA that facilitated the accumulation of TAC HSA-NPs at inflamed arthritis sites. TAC HSA-NPs are a promising drug delivery system to enhance water solubility and increase accumulation in joints for treatment of rheumatoid arthritis.