Challenges in the treatment of Rheumatoid Arthritis

MiR-130a/Ndrg2 Axis Inhibits the Proliferation of Fibroblast-Like Synoviocytes in Rheumatoid Arthritis

Studies have found that N-myc downstream-regulated gene 2 (Ndrg2) is involved in the progression of rheumatoid arthritis (RA); however, the specific mechanism still remains unclear. Gene expression profiles in the tibial joints of the collagen-induced rheumatoid arthritis model were obtained using Gene Expression Omnibus database. Western blot and real-time PCR were respectively performed to determine the expression of Ndrg2 and gene messenger RNA. Cell viability was measured by Cell Counting Kit-8 (CCK-8) method, and cell cycle was detected by flow cytometry. Cell scratch assays were carried out to detect migration. The binding ability of miR-130a to Ndrg2-3'-UTR was predicted by TargetScan website and confirmed by dual luciferase assay. A collagen-induced arthritis rat model was constructed to observe the effects of miR-130a on arthritis index, hind limb swelling, volume of rat hind paw, and inflammation. Ndrg2 was found downregulated in RA tissues, and knockdown of Ndrg2 promoted fibroblast-like synoviocytes (FLS) proliferation and inflammation, while overexpressed Ndrg2 produced opposite results. Ndrg2 was predicted as a target gene for miR-130a, and miR-130a mimic promoted FLS proliferation, while miR-130a inhibitor suppressed FLS proliferation. Moreover, we found that miR-130a antagomir could significantly reduce the arthritis index, swelling degree, foot volume, and inflammatory factor levels; inhibit the expression of miR-130a; and promote the expression of Ndrg2. The miR-130a/Ndrg2 axis signaling pathway is involved in the progression of RA. Our findings provide a theoretical basis for the clinical treatment of RA.

Virtual Screening Technique Used to Estimate the Mechanism of Adhatoda vasica Nees for the Treatment of Rheumatoid Arthritis Based on Network Pharmacology and Molecular Docking

Adhatoda vasica Nees (AVN) is commonly used to treat joint diseases such as rheumatoid arthritis (RA) in ethnic minority areas of China, especially in Tibetan and Dai areas, and its molecular mechanisms on RA still remain unclear. Network pharmacology, a novel strategy, utilizes bioinformatics to predict and evaluate drug targets and interactions in disease. Here, network pharmacology was used to investigate the mechanism by which AVN acts in RA. The chemical compositions and functional targets of AVN were retrieved using the systematic pharmacological analysis platform PharmMapper. The targets of RA were queried through the DrugBank database. The protein-protein interaction network (PPI), Gene Ontology (GO), and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway enrichment analyses of key targets were constructed in the STRING database, and the network visualization analysis was performed in Cytoscape. Maestro 11.1, a type of professional software, was used for verifying prediction and analysis based on network pharmacology. By comparing the predicted target information with the targets of RA-related drugs, 25 potential targets may be related to the treatment of RA, among which MAPK1, TNF, DHODH, IL2, PTGS2, and JAK2 may be the main potential targets for the treatment of RA. Finally, the chemical components and potential target proteins were scored by molecular docking, and compared with the ligands of the protein, the prediction results of network pharmacology were preliminarily verified. The active ingredients and mechanism of AVN against RA were firstly investigated using network pharmacology. Additionally, this research provided a solid foundation for further experimental studies.

Screen the Effective Components of Lycopodii herba on Rheumatoid Arthritis with the Aid of Spectrum-Effect Relationship and Uncover its Potential Mechanism

Lycopodii herba (SJC), a traditional Chinese medicine, has the effect of dispelling wind and eliminating dampness (a therapeutic principle and method of traditional Chinese medicine for rheumatoid arthritis), relaxing tendon and activating collaterals. However, the major effective components and its therapeutic mechanism were unclear. In this study, different SJC samples with slightly different compositions were prepared by extracting with different concentrations of ethanol. Then, the therapeutic effects on rheumatoid arthritis (RA) of different SJC samples were evaluated. Finally, the spectrum-effect relationship between UPLC-Q-TOF/MS fingerprints and the effect of RA was explored to screen the effective components. Western blotting was used to study the potential mechanism. The volume of hind paw and the level of RF, TNF-α, and IL-1β were lower after administrating with different SJC samples, compared with the model group. Histopathological findings also confirmed that SJC could relieve the symptoms of RA. Combined with identification of the components in plasm from SJC, lycojaponicumin C, des-N-methyl-α-obscurine, 8β-acetoxy-12β-hydroxy-lycopodine or 8β-acetoxy-11α-hydroxy-lycopodine or 8β-hydroxy-11α-acetoxylycopodine were considered to be the major effective components. The mechanism may be related to AChE/NF-κB signaling pathway. This work provides a general method to screen the potential effective components of herb medicines and would be benefit to understand the mechanism of SJC for the treatment of RA.

Sigesbeckia glabrescens Makino extract attenuated the collagen-induced arthritis through inhibiting the synovial hyperplasia and inflammation

Background

Sigesbeckia glabrescens Makino (SG) has been traditionally used for rheumatism and joint protection. However, the anti-arthritic effects and underling mechanisms of SG have not been demonstrated. In this study, we investigated the anti-arthritic effects and mechanisms of SG extract (SGE) on collagen-induced arthritic rats and interleukin (IL)-1β-stimulated human synovial SW982 cells.

Methods

Rats were induced to arthritis by collagen for 15 days and then received SGE treatment for 35 days. The body weight and arthritis severity score of the rats were monitored weekly. At the end of the experiment, the radiographic and histological changes of rats’ hind paw were obtained; the serum C-reactive protein was detected by enzyme-linked immunosorbent assay (ELISA); the expression levels of interleukin (IL)- 1β, IL6 and IL-10 in the joint muscles were determined by ELISA and immunohistochemical staining; and the level of regulatory T cells (Tregs) in the spleen was detected using flow cytometry. In addition, 3-(4,5-Dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay and scratch wound healing assay were used to evaluate the proliferation of SW982 synovial cells. ELISA, western blot and immunofluorescence staining were used to investigate the anti-inflammatory mechanisms of SGE on IL-1β-induced SW982 cells and joint muscles of CIA rats.

Results

SGE attenuated the collagen-induced hind paw swelling, cartilage damage and bone erosion. SGE inhibited the synovial hyperplasia to the articular cavity in the toe joint and ankle. Moreover, SGE decreased the production of C-reactive protein in serum and the expression of IL-6, IL-1β, cyclooxygenase-2 (COX-2) and phosphorylation of NF-κB p65 in the joint muscles. SGE also recovered the decreased Tregs. Results from the in vitro experiments showed that SGE not only inhibited the proliferation and migration of human synovial cell but also inhibited the IL-1β-induced expression of IL-6 and IL-8. Similarly, SGE inhibited the activation of NF-κB and the expression of COX-2.

Conclusions

SGE attenuated the collagen-induced arthritis through inhibiting the synovial hyperplasia and inflammation.

Potential mechanisms of action of celastrol against rheumatoid arthritis: Transcriptomic and proteomic analysis

The clinical efficacy for treating of celastrol rheumatoid arthritis (RA) has been well-documented, but its mechanism of action remains unclear. Here we explored through what proteins and processes celastrol may act in activated fibroblast-like synoviocytes (FLS) from RA patients. Differential expression of genes and proteins after celastrol treatment of FLS was examined using RNA sequencing, label-free relatively quantitative proteomics and molecular docking. In this paper, expression of 26,565 genes and 3,372 proteins was analyzed. Celastrol was associated with significant changes in genes that respond to oxidative stress and oxygen levels, as well as genes that stabilize or synthesize components of the extracellular matrix. These results identify several potential mechanisms through which celastrol may inhibit inflammation in RA.

Nanoparticle-siRNA: A potential strategy for rheumatoid arthritis therapy?

Rheumatoid arthritis (RA) is a common clinical inflammatory disease of the autoimmune system manifested by persistent synovitis, cartilage damage and even deformities. Despite significant progress in the clinical treatment of RA, long-term administration of anti-rheumatic drugs can cause a series of problems, including infections, gastrointestinal reactions, and abnormal liver and kidney functions. The emergence of RNA interference (RNAi) drugs has brought new hope for the treatment of RA. Designing a reasonable vector for RNAi drugs will greatly expand the application prospects of RNAi. Nanoparticles as a promising drug carrier provide reliable support for RNAi drugs. The review summarizes the pathogenesis of RA as a possible target for small interference RNA (siRNA) design. At the same time, the review also analyzes the nanoparticles used in siRNA carriers in recent years, laying the foundation and prospect for the next step in the development of intelligent nanocarriers.

Adoptive Treg cell-based immunotherapy: Frontier therapeutic aspects in rheumatoid arthritis

The major current focus on treating rheumatoid arthritis is to put an end to long-term treatments and instead, specifically block widespread immunosuppression by developing antigen-specific tolerance, while also permitting an intact immune response toward other antigens to occur. There have been promising preclinical findings regarding adoptive Treg cells immunotherapy with a critically responsible function in the prevention of autoimmunity, tissue repair and regeneration, which make them an attractive candidate to develop effective therapeutic approaches to achieve this interesting concept in many human immune-mediated diseases, such as rheumatoid arthritis. Ex vivo or invivo manipulation protocols are not only utilized to correct Treg cells defect, but also to benefit from their specific immunosuppressive properties by identifying specific antigens that are expressed in the inflamedjoint. The methods able to address these deficiencies can be considered as a target for immunity interventions to restore appropriate immune function.

Trigger-responsive engineered-nanocarriers and image-guided theranostics for rheumatoid arthritis

Rheumatoid Arthritis (RA), one of the leading causes of disability due to progressive autoimmune destruction of synovial joints, affects ∼1% of the global population. Standard therapy helps in reducing inflammation and delaying the progression of RA but is limited by non-responsiveness on long-term use and several side-effects. The conventional nanocarriers (CNCs), to some extent, minimize toxicity associated with free drug administration while improving the therapeutic efficacy. However, the uncontrolled release of the encapsulated drug even at off-targeted organs limits the application of CNCs. To overcome these challenges, trigger-responsive engineered nanocarriers (ENCs) have been recently explored for RA treatment. Unlike CNCs, ENCs enable precise control over on-demand drug release due to endogenous triggers in arthritic paws like pH, enzyme level, oxidative stress, or exogenously applied triggers like near-infrared light, magnetic field, ultrasonic waves, etc. As the trigger is selectively applied to the inflamed joint, it potentially reduces toxicity at off-target locations. Moreover, ENCs have been strategically coupled with imaging probe(s) for simultaneous monitoring of ENCs inside the body and facilitate an 'image-guided-co-trigger' for site-specific action in arthritic paws. In this review, the progress made in recently emerging 'trigger-responsive' and 'image-guided theranostics' ENCs for RA treatment has been explored with emphasis on the design strategies, mechanism, current status, challenges, and translational perspectives.

Deficiency of STING Promotes Collagen-Specific Antibody Production and B Cell Survival in Collagen-Induced Arthritis

The levels of interferon-alpha are high in the serum and synovial fluid of rheumatoid arthritis (RA) patients. Activation of the stimulator of type I interferon genes (STING) mediates the productions of type I interferon and promotes chronic inflammation. STING plays a significant role in autoimmune lupus mice. However, the function of STING in collagen-induced arthritis (CIA) model has never been described. This study aimed to test the function of STING in CIA. The Sting-deficient mice developed arthritis comparable to WT mice. The levels of anti-collagen antibody from Sting-deficient mice were significantly higher than the WT mice. The B cells derived from Sting-deficient mice showed better survival than WT mice in response to the B cell receptor (BCR) stimulation. Activation of STING also induced B cell death, especially in activated B cells. This study demonstrated that the inhibition of STING promotes anti-collagen antibodies and B cell survival, which suggested that STING acts as a negative regulator of B cell function in the CIA model.

Vitamin D receptor (VDR) gene polymorphism and risk of rheumatoid arthritis (RA): systematic review and meta-analysis

Vitamin D is involved in immune system modulation as well as in calcium and bone homeostasis, hence plays a role in rheumatoid arthritis (RA) etiopathogenesis. A bulk of studies in different populations have assessed the association between the vitamin D receptor (VDR) gene polymorphisms and the risk of RA, reporting conflicting results. Therefore, we designed a meta-analysis to comprehensively evaluate the association of VDR gene polymorphisms and RA risk. All potential studies reporting the association between VDR gene polymorphisms and susceptibility to RA published till February 2020 were retrieved through systematic search of database, including Scopus and MEDLINE. Strength of pooled association was determined through calculating the pooled odds ratios (ORs) and 95% confidence intervals (CIs). Subgroup analysis was performed by stratifying the studies by population type. This meta-analysis included 23 eligible studies (21 articles) overall. We noticed that FokI SNP had a significant protective association with susceptibility to RA in the overall analysis as well as in Europeans and Asians. TaqI SNP decreased the RA risk in Africans and Arabs, but not in the overall analysis. Likewise, BsmI SNP and RA risk in the overall population analysis was not significant. Interestingly, BsmI polymorphism increased RA risk in Africans. This meta-analysis offers a significant association between VDR gene polymorphism and susceptibility to RA in both overall and ethnic-specific analysis. However, different polymorphisms acted inversely in increasing or decreasing RA risk in different populations.

Tanshinone IIA Suppresses Proliferation and Inflammatory Cytokine Production of Synovial Fibroblasts from Rheumatoid Arthritis Patients Induced by TNF-α and Attenuates the Inflammatory Response in AIA Mice

Rheumatoid arthritis (RA) is a chronic and progressive autoimmune disease in which activated RA fibroblast-1ike synoviocytes (RA-FLSs) are one of the main factors responsible for inducing morbidity. Previous reports have shown that RA-FLSs have proliferative features similar to cancer cells, in addition to causing cartilage erosion that eventually causes joint damage. Thus, new therapeutic strategies and drugs that can effectively contain the abnormal hyperplasia of RA-FLSs and restrain RA development are necessary for the treatment of RA. Tanshinone IIA (Tan IIA), one of the main phytochemicals isolated from Salvia miltiorrhiza Bunge, is capable of promoting RA-FLS apoptosis and inhibiting arthritis in an AIA mouse model. In addition, RA patients treated at our clinic with Tan IIA showed significant improvements in their clinical symptoms. However, the details of the molecular mechanism by which Tan IIA effects RA are unknown. To clarify this mechanism, we evaluated the antiproliferative and inhibitory effects of proinflammatory factor production caused by Tan IIA to RA-FLSs. We demonstrated that Tan IIA can restrict the proliferation, migration, and invasion of RA-FLSs in a time- and dose-dependent manner. Moreover, Tan IIA effectively suppressed the increase in mRNA expression of some matrix metalloproteinases and proinflammatory factors induced by TNF-α in RA-FLSs, resulting in inflammatory reactivity inhibition and blocking the destruction of the knee joint. Through the integration of network pharmacology analyses with the experimental data obtained, it is revealed that the effects of Tan IIA on RA can be attributed to its influence on different signaling pathways, including MAPK, AKT/mTOR, HIF-1, and NF-kB. Taken together, these data suggest that the compound Tan IIA has great therapeutic potential for RA treatment.

COVID-19 infection and rheumatoid arthritis: Faraway, so close!

The outbreak of the new coronavirus infections COVID-19 in December 2019 in China has quickly become a global health emergency. Given the lack of specific anti-viral therapies, the current management of severe acute respiratory syndrome coronaviruses (SARS-CoV-2) is mainly supportive, even though several compounds are now under investigation for the treatment of this life-threatening disease. COVID-19 pandemic is certainly conditioning the treatment strategy of a complex disorder as rheumatoid arthritis (RA), whose infectious risk is increased compared to the general population because of an overall impairment of immune system typical of autoimmune diseases combined with the iatrogenic effect generated by corticosteroids and immunosuppressive drugs. However, the increasing knowledge about the pathophysiology of SARS-CoV-2 infection is leading to consider some anti-rheumatic drugs as potential treatment options for the management of COVID-19. In this review we will critically analyse the evidences on either positive or negative effect of drugs commonly used to treat RA in this particular scenario, in order to optimize the current approach to RA patients.

Ginsenoside Rg3 Alleviates Complete Freund's Adjuvant-Induced Rheumatoid Arthritis in Mice by Regulating CD4+CD25+Foxp3+Treg Cells

Ginsenoside Rg3 (GRg3) is one of the major bioactive ingredients of ginseng, which is not only used as a herbal medicine but also used as a functional food to support body functions. In this study, the beneficial effects of GRg3 on rheumatoid arthritis (RA) mice was evaluated from anti-inflammatory and immunosuppressive aspects. The footpad swelling rate, pathological changes of the ankle joint, and levels of tumor necrosis factor α, interleukin 6, interleukin 10, and tumor necrosis factor β were used to assess the anti-inflammatory effect of GRg3 on RA mice. Flow cytometric analysis of CD4⁺CD25⁺Foxp3⁺Treg cell percentage and metabolomic analysis based on gas chromatography-tandem mass spectrometry were used to assess the immunosuppressive effect and underlying mechanisms. GRg3 exhibited anti-inflammatory and immunosuppressive effects on RA mice. The potential mechanisms were related to regulate the pathways of oxidative phosphorylation and enhance the function of CD4⁺CD25⁺Foxp3⁺Treg cells to maintain peripheral immune tolerance of RA mice. These findings can provide a preliminary experimental basis to exploit GRg3 as a functional food or an effective complementary for the adjuvant therapy of RA.

Targeting Granulocyte-Monocyte Colony-Stimulating Factor Signaling in Rheumatoid Arthritis: Future Prospects

Rheumatoid arthritis (RA) is a systemic, autoimmune disease that affects joints and extra-articular structures. In the last decade, the management of this chronic disease has dramatically changed with the introduction of several targeted mechanisms of action, such as tumor necrosis factor-α inhibition, T-cell costimulation inhibition, B-cell depletion, interleukin-6 blockade, and Janus kinase inhibition. Beyond its well-known hematopoietic role on the proliferation and differentiation of myeloid cells, granulocyte-monocyte colony-stimulating factor (GM-CSF) is a proinflammatory mediator acting as a cytokine, with a proven pathogenetic role in autoimmune disorders such as RA. In vitro studies clearly demonstrated the effect of GM-CSF in the communication between resident tissue cells and activated macrophages at chronic inflammation sites, and confirmed the elevation of GM-CSF levels in inflamed synovial tissue of RA subjects compared with healthy controls. Moreover, a pivotal role of GM-CSF in the perception of pain has been clearly confirmed. Therefore, blockade of the GM-CSF pathway by monoclonal antibodies directed against the cytokine itself or its receptor has been investigated in refractory RA patients. Overall, the safety profile of GM-CSF inhibitors seems to be very favorable, with a particularly low incidence of infectious complications. The efficacy of this new mechanism of action is comparable with main competitors, even though the response rates reported in phase II randomized controlled trials (RCTs) appear to be numerically lower than the response rates observed with other biological disease-modifying antirheumatic drugs already licensed for RA. Mainly because of this reason, nowadays the development program of most GM-CSF blockers for RA has been discontinued, with the exception of otilimab, which is under evaluation in two phase III RCTs with a head-to head non-inferiority design against tofacitinib. These studies will likely be useful for better defining the potential role of GM-CSF inhibition in the therapeutic algorithm of RA. On the other hand, the potential role of GM-CSF blockade in the treatment of other rheumatic diseases is now under investigation. Phase II trials are ongoing with the aim of evaluating mavrilimumab for the treatment of giant cell arteritis, and namilumab for the treatment of spondyloarthritis. Moreover, GM-CSF inhibitors have been tested in osteoarthritis and diffuse subtype of systemic sclerosis. This review aims to describe in detail the available evidence on the GM-CSF blocking pathway in RA management, paving the way to a possible alternative treatment for RA patients. Novel insights regarding the potential use of GM-CSF blockers for alternative indications will be also addressed.

Discovery of diaminopyrimidine-carboxamide derivatives as JAK3 inhibitors

Selective inhibition of janus kinase (JAK) has been identified as an important strategy for the treatment of autoimmune disorders. Optimization at the C2 and C4-positions of pyrimidine ring of Cerdulatinib led to the discovery of a potent and orally bioavailable 2,4-diaminopyrimidine-5-carboxamide based JAK3 selective inhibitor (11i). A cellular selectivity study further confirmed that 11i preferentially inhibits JAK3 over JAK1, in JAK/STAT signaling pathway. Compound 11i showed good anti-arthritic activity, which could be correlated with its improved oral bioavailability. In the repeat dose acute toxicity study, 11i showed no adverse changes related to gross pathology and clinical signs, indicating that the new class JAK3 selective inhibitor could be viable therapeutic option for the treatment of rheumatoid arthritis.

Detection and Comparative Analysis of Methylomic Biomarkers of Rheumatoid Arthritis

Rheumatoid arthritis (RA) is a common autoimmune disorder influenced by both genetic and environmental factors. To investigate possible contributions of DNA methylation to the etiology of RA with minimum confounding genetic heterogeneity, we investigated genome-wide DNA methylation in disease-discordant monozygotic twin pairs. This study hypothesized that methylomic biomarkers might facilitate accurate RA detection. A comprehensive series of biomarker detection algorithms were utilized to find the best methylomic biomarkers for detecting RA patients using the methylomic data of the peripheral blood samples. The best model achieved 100.00% in accuracy (Acc) with 81 methylomic biomarkers and a 10-fold cross-validation (10FCV) strategy. Some of the methylomic biomarkers were experimentally confirmed to be associated with the onset or development of RA. It is also interesting to observe that many of the detected biomarkers were from chromosome Y, supporting the knowledge that RA has a significant gender discrepancy.

Therapeutic targets of thunder god vine (Tripterygium wilfordii hook) in rheumatoid arthritis (Review)

Celastrol and triptolide, chemical compounds isolated from Tripterygium wilfordii hook (also known as thunder god vine), are effective against rheumatoid arthritis (RA). Celastrol targets numerous signaling pathways involving NF‑κB, endoplasmic reticulum Ca2+‑ATPase, myeloid differentiation factor 2, toll‑like receptor 4, pro‑inflammatory chemokines, DNA damage, cell cycle arrest and apoptosis. Triptolide, inhibits NF‑κB, the receptor activator of NF‑κB (RANK)/RANK ligand/osteoprotegerin signaling pathway, cyclooxygenase‑2, matrix metalloproteases and cytokines. The present review examined the chemistry and bioavailability of celastrol and triptolide, and their molecular targets in treating RA. Clinical studies have demonstrated that T. wilfordii has several promising bioactivities, but its multi‑target toxicity has restricted its application. Thus, dosage control and structural modification of T. wilfordii are required to reduce the toxicity. In this review, future directions for research into these promising natural products are discussed.

Autoimmune thyroid disorders and rheumatoid arthritis: A bidirectional interplay

Rheumatoid arthritis (RA) and autoimmune thyroid disease (AITD) can occur in the same patient in the autoimmune polyglandular syndrome 2. The association of the two conditions has been recognized long-time ago and the prevalence of AITD in patients with RA and vice versa is well assessed. Geographical variation of AITD and related autoantibodies in RA patients is partly due to ethnic and environmental differences of the studied populations. The impacts of thyroid disorders on RA outcome and vice versa are still controversy. In both AITD and RA genetic susceptibility and environmental factors play a synergic role in the development of the diseases. In this review we aimed at investigating the association of AITD and thyroid autoantibodies with RA, the common pathogenic pathways, the correlation with RA disease activity, and influence of the treatment.

MTHFR gene polymorphisms and susceptibility to rheumatoid arthritis: a meta-analysis based on 16 studies

Rheumatoid arthritis (RA) is the most common autoimmune rheumatic disease, in which an epigenetic implication in the disease etiopathogenesis has been noted. Here in this meta-analysis, we attempted to investigate the pooled association of methylenetetrahydrofolate reductase (MTHFR) gene C677T and A1298C polymorphisms and susceptibility to RA risk. A systematic search was performed in the main databases, including MEDLINE and Scopus to search for studies assessing the association between MTHFR gene C677T and A1298C polymorphisms and the risk of RA prior to December 2019. In this meta-analysis, 15 studies with 2165 patients and 1751 healthy controls for C677T SNP and 14 studies containing 2021 patients and 1760 healthy controls for A1298C SNP were included. A significant positive association between C677T SNP and RA risk was recognized in the dominant, recessive, and allelic model, but not TT and CT genotypes. The results indicated that the risk of RA in African population was increased under all genotype models while these results were repeated in Asian population just for recessive model, allelic model, and TT genotype. Moreover, the analysis of A1298C SNP demonstrated a significant association in overall population according to only the recessive model and CC genotype. Subgroup analysis according to the genotyping method indicated that RFLP-PCR method could impress the results of association between MTHFR gene A1298C and C677T SNPs and RA risk. The outcome of this meta-analysis indicated that MTHFR gene C677T SNP was much possibly be associated with RA risk.

MiR-145-5p mitigates dysregulated Wnt1/β-catenin signaling pathway in rheumatoid arthritis

Fibroblast-like synoviocytes (FLS) lining the arthritic synovial joint region have been implicated to be a key player in bone remodeling. The uncontrolled proliferation of this cell subtype is strictly regulated by various molecular elements including microRNAs (miRNAs). The Wnt1/β-catenin signaling pathway plays a crucial role in the survival of FLS cells. This study explores the underlying mechanism of miR-145-5p towards the Wnt1/β-catenin pathway. MiR-145-5p depicted a strong binding affinity towards frizzled class receptor 4 (FZD4) 3' UTR, a key receptor complex essential for recognizing circulating Wnt1 molecules. Adjuvant induced arthritic fibroblast-like synoviocytes (AA-FLS) isolated from rats stimulated with Wnt1 (10 ng/ml) elicited active Wnt1/β-catenin signaling. Transfection of miR-145-5p mimic (50 pmol) to AA-FLS stimulated with Wnt1 elicited reduced expression levels of various factors of Wnt1/β-catenin signaling including low-density lipoprotein receptor-related protein 5 (LRP5), dishevelled segment polarity protein 1 (Dvl1) and β-catenin transcription factor. Moreover, pro-inflammatory cytokines (TNFα, IL-1β, IL-6 and IL-23) were regulated compared to the diseased groups. Furthermore, miR-145-5p counterbalanced the levels of receptor activator of nuclear factor kappa B ligand (RANKL) and osteoprotegerin (OPG) at the cellular level, essential for bone remodeling. Hence, we suggest that miR-145-5p regulates the survival/proliferation of FLS cells in RA disease condition through attenuation of Wnt1/β-catenin signaling.

Berberine encapsulated PEG-coated liposomes attenuate Wnt1/β-catenin signaling in rheumatoid arthritis via miR-23a activation

Bone erosion is a debilitating pathological process of osteopathic disorder like rheumatoid arthritis (RA). Current treatment strategies render low disease activity but with disease recurrence. To find an alternative, we designed this study with an aim to explore the underlying therapeutic effect of PEGylated liposomal BBR (PEG-BBR) against Wnt1/β-catenin mediated bone erosion in adjuvant-induced arthritic (AA) rat model and fibroblast-like synoviocytes (FLS) with reference to microRNA-23a (miR-23a) activity. Our initial studies using confocal microscopy and Near-Infrared Imaging (NIR) showed successful internalization of PEG-BBR and PEG-miR-23a in vitro and in vivo respectively and was retained till 48 h. The preferential internalization of PEG-BBR into the inflamed joint region significantly reduced the gene and protein level expression of major Wnt1 signaling mediators and reduced bone erosion in rats. Moreover, PEG-BBR treatment in FLS cells attenuated the gene and protein expression levels of FZD4, LRP5, β-catenin, and Dvl-1 through the induction of CYLD. Furthermore, inhibition of these factors resulted in reduced bone loss and increased calcium retainability by altering the RANKL/OPG axis. PEG-BBR treatment markedly inhibited the expression of LRP5 protein on par with the DKK-1 (LRP5/Wnt signaling inhibitor) and suppressed the transcriptional activation of β-catenin inside the cells. We further witnessed that miR-23a altered the expression levels of LRP5 through RNA interference. Overall, our findings endorsed that miR-23a possesses a multifaceted therapeutic efficiency like berberine in RA pathogenesis and can be considered as a potential candidate for therapeutic targeting of Wnt1/β-catenin signaling in RA disease condition.

Prediction of triptolide targets in rheumatoid arthritis using network pharmacology and molecular docking

Network pharmacology is a novel approach that uses bioinformatics to predict and identify multiple drug targets and interactions in disease. Here, we used network pharmacology to investigate the mechanism by which triptolide acts in rheumatoid arthritis (RA). We first searched public databases for genes and proteins known to be associated with RA, as well as those predicted to be targets of triptolide, and then used Ingenuity Pathway Analysis (IPA) to identify enriched gene pathways and networks. Networks and pathways that overlapped between RA-associated proteins and triptolide target proteins were then used to predict candidate protein targets of triptolide in RA. The following proteins were found to occur in both RA-associated networks and triptolide target networks: CD274, RELA, MCL1, MAPK8, CXCL8, STAT1, STAT3, c-JUN, JNK, c-Fos, NF-κB, and TNF-α. Docking studies suggested that triptolide can fit in the binding pocket of the six top candidate triptolide target proteins (CD274, RELA, MCL1, MAPK8, CXCL8 and STAT1). The overlapping pathways were activation of Th1 and Th2 cells, macrophages, fibroblasts and endothelial cells in RA, while the overlapping networks were involved in cellular movement, hematological system development and function, immune cell trafficking, cell-to-cell signaling and interaction, inflammatory response, cellular function and maintenance, and cell death and survival. These results show that network pharmacology can be used to generate hypotheses about how triptolide exerts therapeutic effects in RA. Network pharmacology may be a useful method for characterizing multi-target drugs in complex diseases.

Interaction between food antigens and the immune system: Association with autoimmune disorders

It has been shown that environmental factors such as infections, chemicals, and diet play a major role in autoimmune diseases; however, relatively little attention has been given to food components as the most prevalent modifiers of these afflictions. This review summarizes the current body of knowledge related to different mechanisms and associations between food proteins/peptides and autoimmune disorders. The primary factor controlling food-related immune reactions is the oral tolerance mechanism. The failure of oral tolerance triggers immune reactivity against dietary antigens, which may initiate or exacerbate autoimmune disease when the food antigen shares homology with human tissue antigens. Because the conformational fit between food antigens and a host's self-determinants has been determined for only a few food proteins, we examined evidence related to the reaction of affinity-purified disease-specific antibody with different food antigens. We also studied the reaction of monoclonal or polyclonal tissue-specific antibodies with various food antigens and the reaction of food-specific antibodies with human tissue antigens. Examining the assembled information, we postulated that chemical modification of food proteins by different toxicants in food may result in immune reaction against modified food proteins that cross-react with tissue antigens, resulting in autoimmune reactivity. Because we are what our microbiome eats, food can change the gut commensals, and toxins can breach the gut barrier, penetrating into different organs where they can initiate autoimmune response. Conversely, there are also foods and supplements that help maintain oral tolerance and microbiome homeostasis. Understanding the potential link between specific food consumption and autoimmunity in humans may lay the foundation for further research about the proper diet in the prevention of autoimmune diseases.

Molecular characterization of three intestinal protozoans in hospitalized children with different disease backgrounds in Zhengzhou, central China

Background

Cryptosporidium spp. and Giardia duodenalis are major intestinal pathogens that can cause diarrheal diseases in humans, especially children. Enterocytozoon bieneusi is another parasite which can cause gastrointestinal tract disorders, with diarrhea being the main clinical symptom. However, few genetic studies of these parasites in pediatric inpatients in China have been published.

Methods

To assess the genetic characteristics and epidemiological status of these parasites, a total of 2284 fecal samples were collected from children in the pediatric departments of three hospitals in Zhengzhou, central China, and screened for these protozoans with PCR, based on the small subunit ribosomal RNA (SSU rRNA) genes of Cryptosporidium spp. and G. duodenalis and the internal transcribed spacer (ITS) of E. bieneusi.

Results

Six (0.26%), 14 (0.61%), and 27 (1.18%) of the samples were positive for Cryptosporidium spp., G. duodenalis and E. bieneusi, respectively. Of the 12 successfully sequenced G. duodenalis isolates, four were identified as assemblage A and eight as assemblage B. In subtype and multilocus genotype (MLG) analyses, C. parvum IIdA19G1 (n = 4) and two novel G. duodenalis MLGs belonging to subassemblage AII (n = 3) and BIV (n = 5) were successfully identified. The E. bieneusi isolates included genotypes D (n = 17), J (n = 2), PigEBITS7 (n = 1), BEB6 (n = 1), and CM8 (n = 1). This is the first report of C. parvum subtype IIdA19G1 in HIV-negative children and E. bieneusi genotype CM8 in humans.

Conclusions

The dominance of zoonotic C. parvum subtype IIdA19G1 indicates that this parasite is turning into zoonotic origin from human-to-human transmission. The phylogenetic analysis also revealed the zoonotic origins and anthroponotic transmission potential of G. duodenalis and E. bieneusi, suggesting more efforts must be made to minimize the threat these pathogens pose to public health.

The Giants (biologicals) against the Pigmies (small molecules), pros and cons of two different approaches to the disease modifying treatment in rheumatoid arthritis

Rheumatoid arthritis (RA) is a chronic autoimmune inflammatory disease that, if untreated, can lead to disability and reduce the life expectancy of affected patients. Over the last two decades the improvement of knowledge of the pathogenetic mechanisms leading to the development of the disease has profoundly changed the treatment strategies of RA through the development of biotechnological drugs (bDMARDs) directed towards specific pro-inflammatory targets involved in the RA network. To date, the therapeutic armamentarium for RA includes ten bDMARDs able to produce the depletion B-cells, the blockade of three different pro-inflammatory cytokines (tumour necrosis factor alpha, interleukin-6 and interleukin-1), or the inhibition of T-cell co-stimulation. The introduction of these new compounds has dramatically improved outcomes in the short and long term, although still a significant proportion of patients are unable to reach or maintain the treatment target over time. The identification of the fundamental role of Janus kinases in the process of transduction of the inflammatory signal within the immune cells has recently provided the opportunity to use the new pharmacological class of small molecules for the therapy of RA, further increasing the number of treatment options. In this review the PROS and CONS of these two drug classes will be discussed, trying to provide the evidence currently available to make the right choice based on the analysis of the efficacy and safety profile of the different drugs on the market and close to marketing.

The therapeutic effects of edaravone on collagen-induced arthritis in rats

Current research suggests that synovial phagocytic cells remove excessive amounts of free oxygen radicals (reactive oxygen species [ROS]), thereby preventing damage to synovial tissues. Moreover, ROS may affect the expression of growth arrest and DNA damage inducible α (GADD45A), thus further promoting the activation of synovial fibroblasts. Male adult rats were assessed for progression of collagen-induced arthritis (CIA) using a macroscopic arthritis scoring system of the hind paws and by measuring the changes in the rat's body weight, and activity level before and after diagnosis of CIA. Rats were intraperitoneally injected twice daily with edaravone at doses of 3, 6, and 9 mL/kg. Samples were taken at 2, 4, and 6 weeks, respectively. Edaravone was found to significantly reduce macroscopic arthritis and microscopic pathology scores in CIA rats. The concentration of endothelial nitric oxide synthase-6, glutathione, and heme oxygenase-1 in the serum of rats decreased, as was the production of ROS around the synovium and inflammatory factors. Moreover, ROS-1 increased the expression of the nuclear factor-κB (NF-κB) p65 protein by altering the expression level of GADD45A, causing aggravation of tissue damage. Edaravone also significantly improved the physiological condition of CIA rats, including appetite, weight changes, and loss of fur, as well as limb mobility. We believe that edaravone acts to reduce the expression of NF-ĸB p65 by clearing ROS, which causes reduced expression of GADD45A, and subsequently reduces the level of apoptosis and inflammatory response proteins, thereby reducing the symptoms of CIA. We, therefore, propose that edaravone is an effective option for clinical treatment of rheumatic arthritis.

Diagnostic accuracy of digital X-ray radiogrammetry on hand bone loss for patients with rheumatoid arthritis

BACKGROUND

This study will aim to evaluate the diagnostic accuracy of digital X-ray radiogrammetry (DXR) on hand bone loss (HBL) for rheumatoid arthritis (RA).

METHODS

In this study, we will search the literature from PubMed, EMBASE, Cochrane Library, PsycINFO, Web of Science, Google Scholar, Cumulative Index to Nursing and Allied Health Literature, Allied and Complementary Medicine Database, Chinese Biomedical Literature Database, China National Knowledge Infrastructure, and WANFANG from the inception to June 1, 2019 without language restrictions. All case-controlled studies on assessing diagnostic accuracy of DXR on HBL for diagnosis of RA will be included. Quality Assessment of Diagnostic Accuracy Studies tool will be used for eligible studies. We will apply RevMan V.5.3 software and Stata V.12.0 software for statistical analysis.

RESULTS

We will evaluate diagnostic accuracy of DXR on HBL in patients with RA by assessing the sensitivity, specificity, positive likelihood ratio, negative likelihood ratio, and diagnostic odds ratio.

CONCLUSION

This study will detect the diagnostic accuracy of DXR evaluation on HBL in patients with RA.

SYSTEMATIC REVIEW REGISTRATION

PROSPERO CRD42019139489.