Induction Of Rheumatoid Arthritis Research Articles

Apical periodontitis as an aggravating factor for the severity of rheumatoid arthritis: An animal study.

The present study investigated the influence of apical periodontitis (AP) on the severity of rheumatoid arthritis (RA) using a Wistar rat model. Forty male Wistar rats were distributed across four groups (n = 10) based on the induction of RA and AP: Control, RA, AP, and RA + AP. RA was induced through two immunisations with type II collagen emulsified in incomplete Freund's adjuvant, followed by one immunisation with complete Freund's adjuvant. After 21 days of RA induction, AP was induced by exposing the pulp of four molars. Animals were euthanized after 28 days of pulp exposure. Through the experiment, visual and behavioural assessments tracked RA development and the knees and hind paw joints were measured. Micro-computed tomography scans of knees and hind paws, as well as mandibles and maxillae, were conducted to evaluate RA severity and the presence of AP, respectively. Serum samples were collected to analyse proinflammatory cytokines (IL-1β, IL-2, IL-17, and TNF-α). Non-parametric data were analysed using the Kruskal-Wallis test followed by Student-Newman-Keuls test, while one-way anova followed by Tukey's test was performed for parametric data. A significance level of 5% was employed. All molars submitted to access cavity developed AP. All joints subjected to arthritis induction developed the disease, with AP + RA demonstrating a higher arthritis severity when compared to the RA group (p < .05). RA + AP group displayed a significantly larger hind paw and knee circumference compared to the RA group (p < .05). Micro-CT images of RA and RA + AP groups revealed joints with erosions and bone deformities, with a significantly lower bone surface density, lower trabecular number and higher trabecular separation in the hind paw and a significantly lower percent bone volume and higher trabecular separation in the knees of RA + AP group compared to RA group (p < .05). RA + AP group exhibited a significantly higher level of TNF-α and a lower level of IL-2 compared to all other groups (p < .05). Both RA and RA + AP groups had significantly higher IL-17 levels (p < .05), while there was no significant difference in IL-1β levels among the groups (p > .05). The findings from this study underscore a possible relationship between apical periodontitis and the exacerbation of rheumatoid arthritis.

Huangqin Qingre Chubi Capsule inhibits rheumatoid arthritis by regulating intestinal flora and improving intestinal barrier.

Changes in intestinal flora and intestinal barrier in patients with preclinical and diagnosed rheumatoid arthritis (RA) suggest that intestinal flora and intestinal barrier play an important role in the induction and persistence of RA. Huangqin Qingre Chubi Capsule (HQC) is a clinically effective herbal formula for the treatment of RA, but its therapeutic mechanism has not been fully clarified. In this study, real-time qPCR (RT-qPCR), 16SrRNA sequencing, Western blot (WB), immunofluorescence and other methods were used to investigate whether HQC inhibited RA. Based on research in collages-induced arthritis (CIA) model in mice, human colon cancer cell line (Caco-2), and fibroblast-like synoviocytes (FLS) from RA patients, we found that intestinal flora was disturbed in CIA model group, intestinal barrier was damaged, and lipolyaccharide (LPS) level was increased, and HQC could regulate intestinal flora and intestinal barrier and reduce LPS translocation into blood. Antibiotic depletion weakened the anti-RA effect of HQC, and HQC fecal microbiota transplantation alleviated RA pathology. In addition, LPS increased the expression of RA pathologic factors MMP3, Fibronectin and inflammatory factors IL-6, TNF-α, IL-1β and IL-8, indicating that elevated peripheral blood level of LPS was related to RA pathology. The dysregulation of intestinal flora and the disruption of intestinal barrier are significant factors in the development of RA. HQC improves RA by regulating intestinal flora, intestinal barrier and inhibiting LPS translocation into blood. The study unveiles RA's new pathogenesis and laid a scientific groundwork for advancing HQC therapy for RA.

MicroRNA-150 Deletion Reduces the Occurrence and Severity of Rheumatoid Arthritis by Inhibiting IL-17.

Understanding the effects of epigenetic factors on the pathogenesis of rheumatoid arthritis (RA) is important for the early diagnosis and therapeutic intervention of this disease. MicroRNA-150 (miR-150) exerts an important influence on the development and function of lymphocytes. However, the role of miR-150 in the pathogenesis of RA remains unclear. To explore the role of miR-150 in the pathogenesis of RA and the related immune mechanism. In this study, we used miR-150 knock-out (miR-150KO) and created animal models of RA. Flow cytometry, immunohistochemistry, and real-time RT-PCR were employed to assess the frequency of T cell subsets and cytokines expression. Compared to wild-type (WT) mice, the onset of RA was postponed and the incidence of RA was reduced in miR-150KO mice. The expression of IL-4 and IFN-γ significantly increased while the expression of IL-17 decreased significantly in NKT and CD4+ T cells of KO mice compared to that of WT mice after RA induction. In addition, the expression of IL-4 and IFN-γ increased while the expression of IL-17 decreased significantly in the joint tissues of KO mice compared to that of WT mice. Furthermore, the mRNA expression of TNF-α and IL-17 decreased significantly in the synovial fluid cells of KO mice compared to that of the WT mice after RA induction. MiR-150 deficiency decreases the expression of IL-17 in T cells and joint tissues, and alleviates the occurrence and progression of RA in mice.

Assessment of Formaldehyde-Induced Arthritis (FIA) using Modified Rheumatoid Arthritis Disease Activity Index (RADAI) on Adult Male Wistar Rats

Rheumatoid Arthritis (RA) is an autoimmune inflammatory and degenerative disease affecting the joints and joint cartilage, with extra-articular manifestations. The chronicity of RA causes irreversible damage to the skeletal system and with a poorly understood pathogenesis, current management modalities are grossly limited. Pre-clinical studies on RA in Africa are plagued with scarcity and inaccessibility of research grants and funding, and this has negatively impacted interest in research. Also, inducting agents that mimic the true pathogenesis of diseases such as RA are limited. Therefore, there is a need to find readily available alternatives to promote research studies on RA in our environment. This study aimed to evaluate the rheumatoid arthritis disease activity index (RADAI) of formaldehyde induction (FIA) in comparison to collagen induction (CIA) of arthritis using twenty adult male Wistar rats which were grouped into 5 (A-E) (n=4). Group A, the control group had feed and water only. Groups B, C, and D had two doses of 0.1% formaldehyde (50µl, 100µl, and 200µl, respectively). Group E had 200µl of bovine CII-CFA emulsion (0.2mg/ml). Booster dosage was performed 9 days later by injecting 100µl of bovine CII-CFA emulsion (0.1mg/ml). Body weights, ankle measurements, and blood samples were taken on days 1, 16, and 48, before sacrificing the animals by cervical dislocation. Both ankles were rapidly dissected and processed for histological assessment using Modified Mankin System. We recorded a 100% mortality rate on high-dose formaldehyde administration (Group D), but no mortalities were seen in other groups. In low and moderate dosages of formaldehyde, RA induction was achieved and when compared to Collagen Induced Arthritis (CIA), there was no significant difference noted. We postulate that Formaldehyde Induced Arthritis (FIA) models can serve as a substitute for CIA mimicking the true pathogenesis seen in rheumatoid arthritis.

A Rat Model of Rheumatoid Arthritis: TDZD-8 is Associated with the Protection Against the Induction of the Synovium Knee Joint IL-17A/GSK3&amp;#946;/ROS/&amp;#945;-SMA Axis of Fibrosis

Rheumatoid arthritis (RA) that affects the synovial knee joint causes swelling of the synovial membrane and tissue damage. Interleukin-17A (IL-17A) and the enzyme glycogen synthase kinase-3β (GSK3β) are involved in the pathogenesis of RA. The link between IL-17A, GSK3β, the oxidative stress, and the profibrogenic marker alpha-smooth muscle actin (α-SMA) with and without TDZD-8, GSK3β inhibitor has not been studied before. Consequently, active immunization of rats was performed to induce RA after three weeks using collagen type II (COII) injections. The treated group received daily injection of 1 mg/kg TDZD-8 for 21 days following the immunization protocol (COII+TDZD-8). Blood and synovium tissue samples were harvested at the end of the experiment. RA development was confirmed as corroborated by a substantial increase in blood levels of the highly specific autoantibody for RA, anti-citrullinated protein antibody as well as augmentation of reactive oxidative species (ROS) levels measured as lipid peroxidation. RA induction also increased synovium tissue levels of IL-17A and the profibrogenic marker, α-SMA. All these parameters seemed to be significantly (p<0.0001) ameliorated by TDZD-8. Additionally, a significant correlation between IL-17A, ROS, and α-SMA and biomarkers of RA was observed. Thus, knee joint synovium RA induction augmented IL-17A/GSK3β/ROS/α-SMA axis mediated arthritis in a rat model of RA, which was inhibited by TDZD-8.

Ameliorating Effects of Coriander on Gastrocnemius Muscles Undergoing Precachexia in a Rat Model of Rheumatoid Arthritis: A Proteomics Analysis.

Coriander is a commonly used vegetable, spice, and folk medicine, possessing both nutritional and medicinal properties. Up to two-thirds of patients with rheumatoid arthritis (RA) exhibit loss of body mass, predominately skeletal muscle mass, a process called rheumatoid cachexia, and this has major effects of the quality of life of patients. Owing to a lack of effective treatments, the initial stage of cachexia has been proposed as an important period for prevention and decreasing pathogenesis. In the current study, we found that cachexia-like molecular disorders and muscle weight loss were in progress in gastrocnemius muscle after only 5 days of RA induction in rats, although rheumatoid cachexia symptoms have been reported occurring approximately 45 days after RA induction. Oral administration of coriander slightly restored muscle loss. Moreover, iTRAQ-based quantitative proteomics revealed that coriander treatment could partially restore the molecular derangements induced by RA, including impaired carbon metabolism, deteriorated mitochondrial function (tricarboxylic acid cycle and oxidative phosphorylation), and myofiber-type alterations. Therefore, coriander could be a promising functional food and/or complementary therapy for patients with RA against cachexia.

Could omega-3 fatty acids preserve endothelial function in a rat model of rheumatoid arthritis?

Could omega-3 fatty acids preserve endothelial function in a rat model of rheumatoid arthritis? Background: Endothelial dysfunction is claimed to be the cause of increased risk for cardiovascular diseases in rheumatoid arthritis (RA) patients. Omega-3 fatty acids is a promising drug in this field; however, its exact effects on endothelial functions are not fully understood. Aim of the work: This study aimed to evaluate the effect of omega-3 fatty acids on endothelial reactivity and some markers of endothelial dysfunction [Vascular cell adhesion molecule-1 (VCAM-1), tumour necrosis factor alpha (TNF-α), Malondialdehyde (MDA) and NOS activity] in a rat model of rheumatoid arthritis. Material & methods: Thirty male rats were divided into 3 groups (control, untreated RA, and RA group with omega-3 supplementation). RA induction was done by intradermal injection of heat-killed Mycobacterium butyricum and was confirmed by clinical signs of arthritis on day 11. In the treated group, omega-3 was given daily via gastric gavage starting from day 11 until the end of the study. The study duration was 30 days for all groups starting from the day of induction. At the end of the study, rats were sacrificed, blood samples were collected for VACM-1, TNF-α, MDA and nitrite measurement and thoracic aortae were taken to test vascular reactivity. Results: All markers increased while vascular reactivity decreased significantly after RA induction. Omega-3 treatment significantly decreased all biochemical markers and restored normal vascular reactivity in the treated group.

Adverse effect of rheumatoid arthritis on male Wistar rat’s fertility: protective role of Costus extract

Rheumatoid arthritis (RA) is a systemic autoimmune complaint. Advanced treatments resort to the traditional herbal therapy. The aim of this study is to assess the protective effect of Costus extract on the fertility of male rats with Freund's adjuvant-induced rheumatoid arthritis. Thirty male adult Wistar rats (190-200 g) were divided into six groups. They were subdivided into three groups; group I was the control group that received distilled water, and groups II and III received two various doses of Costus extract (200 and 400 mg/kg, respectively) for 60 days. Another three groups were subjected to RA induction via Freund's adjuvant. Rats were injected a dose of 0.1 ml of Freund's complete adjuvant (FCA) in the planter area of the left hind paw and then subdivided into 3 groups. Group I of RA-induced rats were given distilled water. The other two groups were given orally (200 and 400 mg/kg dosage of extract, respectively) from the 2nd day of RA induction for 60 days. Sex organ relative weight, sperm concentration assay, testicular histopathology and immunohistochemistry of androgen receptors, TNF α, and BAX protein were determined. The results showed that RA caused a significant decrease in the relative weight of sex organs and sperm count, which were relatively improved by doses of Costus (200, 400 mg/kg). RA induction caused testicular degeneration which markedly enhanced with Costus treatment as shown in histopathological sections. RA caused a reduction in %IHC of androgen receptors and increased expression level of both TNF α and BAX protein. Using IHC, it was revealed that RA caused a reduction in the expression level of androgen receptors and an increase in the expression of both TNF α and BAX protein. We can conclude that Costus speciosus had a potentially valuable role in improving fertility disorders caused by RA.

Anti-inflammatory and Hepatoprotective Effects of Quercetin in an Experimental Model of Rheumatoid Arthritis.

Rheumatoid arthritis (RA) is an autoimmune disease characterized by inflammation in the joints. Although methotrexate (MX) is the first-line treatment, side effects are common. This study aimed to investigate the effects of quercetin (QT) and/or MX on inflammation and systemic toxicity in a rat model of RA. Male Wistar rats were divided into control (C), RA, QT, MX, and QT + MX groups (n=6). The RA induction consisted of three intra-articular injections of methylated bovine serum albumin (1×/week) in the temporomandibular joint (TMJ). QT (25 mg/kg) and/or MX (0.75 mg) administration occurred by oral gavage daily. We performed mechanical hyperalgesia in TMJ, leukocyte recruitment in synovial fluid, histopathology, and immunohistochemistry (TNF-α, IL-17, and IL-10) in synovial membrane and toxicity parameters. The RA showed a reduction in the nociceptive threshold (p<0.001), increase in leukocyte recruitment in synovial fluid (p<0.001), intense inflammatory infiltrate (p<0.001), and intense immunoexpression of TNF-α, IL-17, and IL-10 in the synovial membrane (p<0.001) compared to C (p<0.001). QT and/or MX therapy reduced inflammatory parameters (p<0.001). However, downregulation of IL-10 was observed only in the groups that received MX (p<0.001). Leukocytosis was seen in RA (p<0.05), but QT and/or MX reversed it (p<0.05). MX was associated with pathological changes in the liver and higher levels of transaminases when compared to the other groups (p<0.05). QT co-administered with MX reversed this hepatotoxicity (p<0.05). There were no alterations in the kidney between the groups (p>0.05). QT has potential to support MX therapy, showing anti-inflammatory and hepatoprotective effects in this model.

Comparative evaluation of the protective effects of oral administration of auraptene and umbelliprenin against CFA-induced chronic inflammation with polyarthritis in rats

This study aimed to evaluate the anti-inflammatory effect of Auraptene (AUR) and Umbelliprenin (UMB) in a rat model of rheumatoid arthritis (RA) induced by using complete Freund's adjuvant (CFA).Paw swelling of adjuvant arthritis rats measured at various times after CFA injection. Over 15 days of RA induction, mediator/cytokine-mediated processes involved in managing the regulation and resolving RA's inflammation were also quantified with ELISA. Histopathological changes were also assessed under a microscope 15 days after the CFA injection.AUR at all doses and UMB administration only at a 16 mM /kg administration dose significantly reduced CFA-induced paw edema level compared to the control group. UMB (64 and 32 mM) and AUR (64, 32, and 16 mM) could reduce the PGE2 (p < .0001–.01) and NO (p < .0001–.05) levels in the treatment groups compared to the negative control group. However, these compounds showed no significant effect on the TNF-α, IFN-γ, TGF-β, IL-4, and IL-10 levels than the control group (p > .05). Unlike indomethacin and prednisolone, treatment of rats with AUR (16, 32, and 64 mM/kg) and UMB (16 and 32 mM/kg) reduced the level of IL-2 (p < .0001). In all treatment groups, the serum level of IL-17 was significantly reduced compared to the CFA group (p < .001–0.05).We suggested AUR and UMB could diminish inflammation by reducing the serum level of IL-17 and could be considered a proper alternative in the treatment of IL-17 related inflammatory diseases such as rheumatoid arthritis. Given that AUR and UMB apply their anti-inflammatory effects by changing distinct cytokine release/inhibition patterns, their potential application in diverse inflammatory diseases seems different.

Roles of Serum Amyloid A 1 Protein Isoforms in Rheumatoid Arthritis

Abstract Secondary amyloid A amyloidosis, a lethal complication, is induced when acute or chronic infection coexists with over-secretion of the serum amyloid A 1 (SAA1) protein and deposition in key internal organs. Previously, using the whole-exome sequencing method, we identified a novel deleterious mutation SAA1.2 in rheumatoid arthritis (RA) patients. However, the role of SAA1 in RA pathogenesis and its complications remains unknown. The purpose of this study was to determine the pathogenetic roles of SAA1 protein isoforms in RA progression. We modified an experimental adenovirus infection protocol to introduce SAA1.2 gene alleles into the knee joints of mice and used SAA1.3 and SAA1.5 as controls. Micro-computed tomography analysis was applied to determine changes in bone morphology and density. Immunohistochemical (IHC) analysis, flow cytometry, enzyme-linked immunosorbent assay (ELISA), and real-time polymerase chain reaction (RT-PCR) were used to investigate disease progression and cytokine alterations in the course of adenoviral SAA-induced knee joint inflammation and bone destruction. We found that the arthritis-inducing effect of SAA1.2 transcription in the knee joints and mutant SAA1 protein secretion in blood resulted in the stimulation of immune responses, leading to CD8+ T cell and pro-inflammatory cytokine elevation, such as interleukin (IL)-6, IL-22, matrix metalloproteinase (MMP)-3, MMP-9, with subsequent synovial inflammation and bone destruction. These findings indicate that SAA1 protein isoforms, particularly SAA1.2, play a significant role in the induction and progression of RA and may have potential value in the early diagnosis and severity prediction of RA.

Electroacupuncture Reduces Inflammation but Not Bone Loss on Periodontitis in Arthritic Rats.

Periodontitis and rheumatoid arthritis (RA) are inflammatory diseases characterized by chronic inflammation and bone erosion. Electroacupuncture (EA) shows anti-inflammatory and anti-resorptive effects in experimental periodontitis (EP) and in RA. It is important to investigate whether EA shows these effects in periodontal tissues in the presence of these two inflammatory diseases or not. For this, Wistar rats were divided into six groups: control (C); experimental rheumatoid arthritis (RA; bovine type II collagen-induced (CII)); experimental periodontitis (EP); RA/EP (RA + EP); EP/EA (EP treated with EA); RA/EP/EA (RA + EP treated with EA). EP was induced 21days after RA induction and EA was performed previously and during the EP induction period, every 3days until the 36th experimental day. The rats were euthanized on day 39. RA was evaluated by edema and the withdrawal threshold of hind paws. The maxillae were removed, and alveolar bone loss (ABL) and bone radiographic density (BRD) were evaluated. Immunohistochemical analyses for interleukins (IL)-6 and -17 and nuclear factor (NF)-κB were performed. Our results showed that EA reduced only the pain intensity in arthritic rats. Histomorphometric, macroscopic, and radiographic analyses did not show differences between the control and EP/EA groups. EA caused a reduction in ABL and BRD only in the presence of EP. EA caused a reduction in IL-6 and -17 in all groups, but NF-κB was only reduced in the arthritic rats with EP. In conclusion, EA reduced the inflammation related to periodontitis in arthritic rats but did not prevent ABL.

Ortho-vanillin nanoparticle-doped glucan microspheresexacerbate the anti-arthritic effects of methotrexate in adjuvant-inducedarthritisin rats.

Methotrexate (MTX) commonly used in rheumatoidarthritis (RA)has severe adverse effects. Ortho-vanillin, an inhibitor of Toll-like receptors (TLR), can prevent inflammation. Glucan is a cereal fiber recognized by dectin-1 or β-glucan receptors of phagocytic macrophages. The purpose of the current project was to study the effect of co-administration of MTX and vanillin by targeted delivery to macrophages using β-glucan microspheres to reduce inflammation of RA. MTX and vanillin nanoparticles in bovine serum albumin (BSA) or gelatin were doped in glucan particles (GPs) and characterized for their physical properties. Twenty-four hours after induction of RA in paw of rats, they received normal saline (1mg/kg, ip), MTX (2mg/kg/week, ip), β-glucan (1mg/kg/week, ip), GPs-MTX (2mg/kg/week, ip), GPs-vanillin (200mg/kg/day, po), and GPs-MTX (2mg/kg/week, ip) plus GPs-vanillin (200mg/kg/day, po). The last group received free MTX ip and vanillin po for 14days. Then, joint diameters, TNF-α and IL-6, were evaluated in rats. The particle size of the GPs was 5.3µm. MTX loading efficiency in glucan microspheres was 64.5% and vanillin 44.2%. The microspheres released 88.7% of MTX and 95.1% of vanillin over 24h. The results of in vivo studies showed a significant reduction in paw volume, TNF-α and IL-6 (p < 0.05) in animals treated with combination of MTX and vanillin-doped glucan microspheres compared to the mixture of the two drugs in free form or each drug alone. Co-administration of MTX and vanillin-doped GPs may be more effective than MTX alone in RA.

Evolving concepts of the pathogenesis of rheumatoid arthritis with focus on the early and late stages.

To provide an overview of recently published work covering key mechanisms involved in the pathogenesis of rheumatoid arthritis (RA), with focus on the early and late stages. Present understanding of RA pathogenesis has been mainly focused on the inflammatory process at the established phase of the disease, but recent work has shed light on important molecular and cellular mechanisms involved both at the early and late/refractory stages. In early RA, the involvement of anticitrullinated protein antibodies in RA induction has been identified with a critical role of the IL-23/Th17 axis in the control of their pathogenicity. At the late stage, RA may be viewed as a cell-autonomous genetic and epigenetic disease, characterized by altered cell death pathways in synoviocytes after long-term exposure to inflammation. An improved knowledge of these cell-intrinsic altered pathways is the basis for the targeting of pathogenic synoviocytes, as a new therapeutic alternative against resistance to current treatment targeting the immune system. We summarize these pathological pathways, and their understanding will facilitate the design of new diagnostic tools and therapeutic strategies combining the targeting of pathogenic synoviocytes with current immune-targeted therapies.

Preclinical Evaluation of a Single Intravenous Infusion of hUC-MSC (BX-U001) in Rheumatoid Arthritis

Rheumatoid arthritis (RA) is an inflammatory disease of the joints, which causes severe pain and excessive systemic circulation of harmful inflammatory cytokines. Current treatments are limited, with some patients not responding well, and some experiencing severe and detrimental side effects. Mesenchymal stem cells (MSC) are cell-based therapeutics being evaluated as potent immunomodulators in RA and may provide relief to patients not responding well to drug-based treatments. We evaluated the safety and efficacy of BX-U001 human umbilical cord tissue–derived mesenchymal stem cells (hUC-MSC) to treat RA, in support of a successful investigational new drug application. A collagen-induced arthritis (CIA) mouse model of RA was established in DBA/1 J mice. Mice from the treatment assessment group were given a tail vein infusion of hUC-MSC 24 days after primary RA induction, while control assessment (CA) group mice were given cell-free carrier solution. All animals were evaluated daily for RA symptoms via clinical scoring, blood was taken periodically for cytokine analysis, and mice were dissected at end point for histological analysis. A linear mixed model was used to compare the rate of change among groups. The clinical scores of TA group were significantly reduced compared with CA group (P < 0.01), indicating therapeutic effects. The histological scores of the joints in TA group were significantly lower than those in the CA group (P < 0.05), but had no significant difference compared with Healthy groups (P > 0.05). The concentration of (interleukin) IL-6 in TA group was significantly reduced by 80.0% (P < 0.0001) 2 days after treatment and by 93.4% at the experimental endpoint compared with levels prior to hUC-MSC injection. A single intravenous infusion of hUC-MSC (2 × 106 cells/mouse), to CIA-induced DBA/1 J mice, resulted in significant alleviation of RA symptoms and may provide significant therapeutic benefits in humans.

CDC1 are required for the initiation of collagen-induced arthritis

Rheumatoid arthritis (RA) is chronic autoimmune disease which etiology remains unknown. Several cell types have been described to potentiate/aggravate the arthritic process however the initiating event in synovial inflammation is still elusive. Dendritic cells (DCs) are essential for the initiation of primary immune responses and thus we hypothesized that these cells might be crucial for RA induction. DCs are a heterogeneous population of cells comprising different subsets with distinct phenotype and function. Here we investigated which DC subset(s) is/are crucial for the initiation of the arthritic process.We have previously demonstrated that Flt3−/− mice, with reduced DCs, were protected from collagen induced arthritis (CIA). Here we have shown that GM-CSF derived DCs in Flt3L−/− mice are functional but not sufficient to induce arthritis. Batf3−/− mice lacking both CD103+ and CD8α+ cDC1 were resistant to collagen induced arthritis (CIA), demonstrating that this DC subset is crucial for arthritis development. CEP-701 (a Flt3L inhibitor) treatment prevented CIA induction, and reduced dramatically the numbers CD103+ cDC1s present in the lymph nodes and synovium. Hence this study identified cDC1 as the main subset orchestrating the initiation of cell-mediated immunity in arthritis.

SAA1 Protein Isoforms Induce Rheumatoid Arthritis

Background: Secondary amyloid A amyloidosis, a lethal complication, is induced when acute or chronic infection coexisted with over-secretion of the SAA1 protein and deposition of SAA1 in key internal organs. Previously, using the whole-exome sequencing method, we identified the novel deleterious mutation SAA1.2 in rheumatoid arthritis (RA) patients. However, the role of SAA1 in RA pathogenesis and its complications remains unknown, making early diagnosis and risk prevention difficult. Methods: We modified an experimental adenovirus infection protocol in order to successfully introduce SAA1.2, SAA1.3, SAA1.5 gene alleles into the rear knee joints of C57BL/6 mice. micro-CT analysis was applied to determine changes in bone morphology and density. IHC, flow cytometry, ELISA and real-time PCR were used to investigate disease progression and cytokine alterations in the course of adenoviral SAA-induced knee joint inflammation and bone destruction. Findings: The pathogenetic functions of SAA1.2, SAA1.3 and SAA1.5 protein isoforms in promoting the initiation and progression of RA were determined. We established that SAA1.2 was the most aggressive factor in RA induction and progression. Mechanistically, we found that the arthritis-inducing effect of SAA1.2 transcription in the knee joints and mutant SAA1 protein secretion in blood results in stimulation of immune responses, leading to CD8 + T cell and pro-inflammatory cytokine elevation, with subsequent synovial inflammation and bone destruction. Interpretation: These findings indicate that SAA1 protein isoforms, particularly SAA1.2, play a significant role in the induction and progression of RA and may have potential value in the early diagnosis and severity prediction for RA. Funding Statement: This work was funded by The Science and Technology Development Fund, Macau SAR (file no. FDCT-FDCT-17-002-SKL). Declaration of Interests: The authors declare no competing interests. Ethics Approval Statement: The study protocol was approved by the institutional committee for animal welfare.

Anti-arthritic potential of ethanol and aqueous extracts of stem bark of Cleistopholis patens on complete Freund's adjuvant-induced rheumatoid arthritis in rats

BackgroundTraditional medicine intervention has been used in rheumatoid arthritis (RA) treatment due to limitations of conventional drugs. ObjectiveThis study aimed at evaluating the anti-arthritic potentials of ethanol and aqueous extracts of stem bark of Cleistopholis patens (SBCP) in complete Freund's adjuvant (CFA) induced rheumatoid arthritis in rats. Materials and methodsRheumatoid arthritis was induced in groups 2 to 9 by intradermal injection of 0.1 mlkg−1 chicken type II collagen in CFA into the left hind paw of the rats. Group 1 served as normal control. Group 2 (negative control) received 5 mlkg−1 body weight normal saline while group 3 (positive control) received 10 mg/kg body weight standard drug (indomethacin). Groups 4 to 9 received varied doses of the extracts. After 10 days of RA induction, rats were treated with ethanol and aqueous extracts of SBCP orally at a dose of 400, 600 and 800 mgkg−1 for 21 days. The paw size, body weight changes, inflammatory parameters, lipid peroxidation maker and malondialdehyde (MDA) were assessed. ResultsRheumatoid arthritis induction caused marked (p < 0.05) increase in paw size, inflammatory makers and MDA while significant (p < 0.05) reduction was observed in body weight relative to normal control. Treatment with extracts analogous to indomethacin markedly (p < 0.05) decreased the paw size and caused weight gain while the altered inflammatory parameters and MDA were reversed relative to negative control. ConclusionThe findings suggest that the extracts of SBCP have good antiarthritic potentials comparable to indomethacin and hence could be used in rheumatoid arthritis management.

Myeloid Krüppel-Like Factor 2 Critically Regulates K/BxN Serum-Induced Arthritis.

Rheumatoid arthritis (RA) is an immune-mediated inflammatory disease, and Krüppel-like factor 2 (KLF2) regulates immune cell activation and function. Herein, we show that in our experiments 50% global deficiency of KLF2 significantly elevated arthritic inflammation and pathogenesis, osteoclastic differentiation, matrix metalloproteinases (MMPs), and inflammatory cytokines in K/BxN serum-induced mice. The severities of RA pathogenesis, as well as the causative and resultant cellular and molecular factors, were further confirmed in monocyte-specific KLF2 deficient mice. In addition, induction of RA resulted in a decreased level of KLF2 in monocytes isolated from both mice and humans along with higher migration of activated monocytes to the RA sites in humans. Mechanistically, overexpression of KLF2 decreased the level of MMP9; conversely, knockdown of KLF2 increased MMP9 in monocytes along with enrichment of active histone marks and histone acetyltransferases on the MMP9 promoter region. These findings define the critical regulatory role of myeloid KLF2 in RA pathogenesis.

Herbo-mineral formulation \u2018Ashwashila\u2019 attenuates rheumatoid arthritis symptoms in collagen-antibody-induced arthritis (CAIA) mice model

Rheumatoid arthritis (RA) is a chronic inflammatory autoimmune disorder that affects joints of hands and feet and introduces injury in secondary organs such as cardiac tissue. In the present study, we induced RA in male Balb/c mice (CAIA) using collagen-antibody cocktail (C-Ab) and lipopolysaccharide intraperitoneal injections. Induction of RA in the animals was detected through the loss of body weight, food, and water consumption, pedal edema, increased arthritis score of the paw and ankle, increase in radiological and histological lesion score of ankle and knee joints and enhanced pain perception in the C-Ab induced RA animals. Ashwashila is a herbo-mineral medicine from Indian Ayurvedic system. Human equivalent doses of Ashwashila (ASHW) and standard of care, Methotrexate were given to the CAIA animals for two weeks. ASHW treatment significantly reversed the effect of C-Ab with reduced pedal edema, arthritis score, radiological and histological lesion scores in ankle-joint, knee-joint and articular cartilage, reduced pain perception. These effects were comparable with the Methotrexate treatment. In human monocytic (THP-1) cells, ASHW was found to be biocompatible at in-vitro test doses. The anti-arthritis mechanism of action for ASHW was established through the suppression of pro-inflammatory cytokines such as IL-1β, IL-6, TNF-α; and upstream regulator, NF-κB. Taken together, we show the pre-clinical efficacy of ASHW in reducing RA associated symptoms by controlling inflammation and suggest it as a potential therapeutic candidate for rheumatoid arthritis.