Molecular and Cellular Pathways Contributing to Joint Damage in Rheumatoid Arthritis

Chinese medicine Di-long (Pheretima vulgaris) and its active fraction exhibit anti-rheumatoid arthritis effects by inhibiting CXCL10/CXCR3 chemotaxis in synovium

ETHNOPHARMACOLOGICAL RELEVANCE

Di-Long (Pheretima vulgaris) is a classic animal sourced traditional Chinese medicine. It has been used for the treatment of joint inflammation and arthralgia for over two thousand years due to its effects of Tong-Luo-Zhi-Tong (dredging collaterals and alleviating pain). Our previous study showed that Chinese medicine Di-Long has significant anti-rheumatoid arthritis (RA) effects.

AIM OF THE STUDY

Considering Di-Long as a potential source of active compounds with specific anti-RA therapeutic effects, this research was to obtain the anti-RA target-specific active fraction from Di-Long extracts (DL), and to further explore the chemical basis and verify the anti-RA mechanism of this active fraction.

MATERIALS AND METHODS

Transcriptomic was applied to obtain the main anti-RA targets of DL on human RA fibroblast-like synoviocytes (FLS) and validated by qPCR. The target-corresponding active fraction was isolated from DL by ethanol precipitation and gel chromatography, and analyzed by nanoliter chromatography-mass spectrometry. Anti-RA effects of this active fraction was investigated by collagen-induced arthritis (CIA) in mice, and anti-RA mechanisms were verified in cocultured model of rat FLS and peripheral blood lymphocytes.

RESULTS

We confirmed that CXCL10/CXCR3 was the main anti-RA target of DL. The active fraction - A (2182 - 890 Da) was isolated from DL based on its CXCL10 inhibiting effects in RA-FLS. Fraction A contains 195 peptides (192 were newly discovered), 26 of which might be bioactive and were considered to be the chemical basis of its anti-RA effects. Fraction A significantly ameliorated the joint destruction and overall inflammation in CIA mice, and downregulated CXCR3 expression in mice joint. Fraction A inhibited the chemotaxis of Th-cells in rat peripheral blood lymphocytes towards the TNF-α-induced rat FLS through CXCL10/CXCR3 pathway.

CONCLUSIONS

Our work indicated that active fraction from DL containing small peptides exhibits promising therapeutic effects for RA through inhibiting CXCL10/CXCR3 chemotaxis.

N6‑methyladenosine methyltransferase METTL14 is associated with macrophage polarization in rheumatoid arthritis

Rheumatoid arthritis (RA) is largely caused by the inflammatory response triggered by macrophage polarization. Through epigenetic reprogramming, the inflammatory state of macrophages can be modified. Macrophage polarization is associated with the RNA epigenetic alteration N6-methyladenosine (m6A) RNA methylation. However, the specific function and underlying mechanisms of m6A methylation in the role of macrophage polarization in RA remain to be elucidated. The mRNA expression levels of m6A methylase genes and signaling pathway components associated with RA macrophages were determined in the present study using reverse-transcription quantitative PCR. Methyltransferase 14 (METTL14) protein expression levels were determined using western blot analysis, and the levels of specific cellular secretion factors were determined using ELISA and flow cytometry. The results of the present study demonstrated that elevated METTL14 expression was associated with joint tenderness, and METTL14 expression was positively correlated with both C-reactive protein and rheumatoid factor expression levels. Moreover, METTL14 exhibited potential in the prediction of visual analogue scale. Pro-inflammatory cytokines (TNF-α) and M1 macrophage markers (CD68+CD86+) were also positively associated with METTL14 expression. The results of the Kyoto Encyclopedia of Genes and Genomes analysis revealed that METTL14 was strongly associated with the MAPK signaling pathway. Notably, JNK and ERK2 exhibited a positive correlation with the M1 macrophage marker, CD68+CD86+, which was positively associated with the pro-inflammatory factor, TNF-α. JNK and ERK2 expression levels were markedly increased in the METTL14 high-expression group, compared with in the low-expression group; however, p38 and ERK1 expression levels were not significantly different between these groups. Collectively, the results of the present study demonstrated that METTL14 expression was significantly increased in the peripheral blood and synovial tissue of patients with RA, highlighting the potential association with both immunoinflammatory markers and clinical symptoms. In addition, it was suggested that METTL14 may exacerbate the downstream inflammatory response, through mediating macrophage polarization via the MAPK pathway.

Association between matrix metalloprotease-3 levels and radiographic progression in patients with rheumatoid arthritis: A post hoc analysis from a Japanese Phase 3 clinical trial of peficitinib (RAJ4)

OBJECTIVES

The current study assesses the utility of matrix metalloprotease-3 (MMP-3) as a biomarker for joint damage in patients with rheumatoid arthritis receiving peficitinib.

METHODS

Rheumatoid arthritis patients with inadequate response to methotrexate were randomised to peficitinib 100 mg, peficitinib 150 mg, or placebo, combined with methotrexate, for 52 weeks; patients receiving placebo switched to peficitinib 100/150 mg at Week (W)12/28. This post hoc analysis investigated association between MMP-3 above/below upper limit of normal (ULN) at W12/28 and radiographic progression [modified total Sharp score (mTSS), joint space narrowing score, or erosion score >0.5] at W52 or swollen joint count 66 at W28, stratified by baseline glucocorticoid use and renal function.

RESULTS

MMP-3 levels decreased in both peficitinib-treated groups but more slowly in patients with baseline glucocorticoids and those with radiographic progression at W52. There was no clear correlation between MMP-3 change from baseline (CFB) at W12, CFB in mTSS, joint space narrowing score, or erosion score at W52, or CFB in swollen joint count 66 at W28. More patients with MMP-3 ≤ULN versus >ULN at W12 had radiographic non-progression at W52. MMP-3 normalisation at W12 was significantly associated with mTSS non-progression at W52.

CONCLUSIONS

Normalisation of MMP-3 at W12 may be a predictor for subsequent non-progression of joint damage at W52.

Emerging Landscape of In Vitro Models for Assessing Rheumatoid Arthritis Management

Rheumatoid arthritis (RA) is a complex condition that is influenced by various causes, including immunological, genetic, and environmental factors. Several studies using animal models have documented immune system dysfunction and described the clinical characteristics of the disease. These studies have provided valuable insights into the pathogenesis of inflammatory arthritis and the identification of new targets for treatment. Nevertheless, none of these animal models successfully replicated all the characteristics of RA. Additionally, numerous experimental medications, which were developed based on our enhanced comprehension of the immune system's function in RA, have shown potential in animal research but ultimately proved ineffective during different stages of clinical trials. There have been several novel therapy alternatives, which do not achieve a consistently outstanding therapeutic outcome in all patients. This underscores the importance of employing the progress in in vitro models, particularly 3D models like tissue explants, and diverse multicomponent approaches such as coculture strategies, synovial membrane, articular cartilage, and subchondral bone models that accurately replicate the structural characteristics of RA pathophysiology. These methods are crucial for the advancement of potential therapeutic strategies. This review discusses the latest advancements in in vitro models and their potential to greatly impact research on managing RA.

Anti-rheumatic property and physiological safety of KMU-11342 in in vitro and in vivo models

Rheumatoid arthritis (RA) is a chronic, systemic inflammatory disorder characterized by joint destruction due to synovial hypertrophy and the infiltration of inflammatory cells. Despite substantial progress in RA treatment, challenges persist, including suboptimal treatment responses and adverse effects associated with current therapies. This study investigates the anti-rheumatic capabilities of the newly identified multi-protein kinase inhibitor, KMU-11342, aiming to develop innovative agents targeting RA. In this study, we synthesized the novel multi-protein kinase inhibitor KMU-11342, based on indolin-2-one. We assessed its cardiac electrophysiological safety using the Langendorff system in rat hearts and evaluated its toxicity in zebrafish in vivo. Additionally, we examined the anti-rheumatic effects of KMU-11342 on human rheumatoid arthritis fibroblast-like synoviocytes (RA-FLS), THP-1 cells, and osteoclastogenesis in RAW264.7 cells. KMU-11342 demonstrated the ability to inhibit LPS-induced chemokine inhibition and the upregulation of pro-inflammatory cytokines, cyclooxygenase-2, inducible nitric oxide synthase, p-IKKα/β, p-NF-κB p65, and the nuclear translocation of NF-κB p65 in RA-FLS. It effectively suppressed the upregulation of NLR family pyrin domain containing 3 (NLRP3) and caspase-1 cleavage. Furthermore, KMU-11342 hindered the activation of osteoclast differentiation factors such as RANKL-induced TRAP, cathepsin K, NFATc-1, and c-Fos in RAW264.7 cells. KMU-11342 mitigates LPS-mediated inflammatory responses in THP-1 cells by inhibiting the activation of NLRP3 inflammasome. Notably, KMU-11342 exhibited minimal cytotoxicity in vivo and electrophysiological cardiotoxicity ex vivo. Consequently, KMU-11342 holds promise for development as a therapeutic agent in RA treatment.

Luobitong Potentiates MTX's Anti-Rheumatoid Arthritis Activity via Targeting Multiple Inflammatory Pathways

Background

The LuoBiTong (LBT) capsule, a novel traditional Chinese medicine formulation, is currently in Phase III clinical trials. Preliminary preclinical and Phase II clinical studies suggest its efficacy and safety in treating rheumatoid arthritis (RA). However, the underlying mechanisms of its action remain to be elucidated.This research aims to explore the effects and mechanisms of LBT in conjunction with a maintenance dose of methotrexate (M-MTX) on RA.

Methods

A Collagen-Induced Arthritis (CIA) mouse model was used to evaluate the anti-RA effects of LBT combined with M-MTX. Assessments included foot swelling, arthritis scoring, serum inflammatory factor analysis, and histopathological examination of the foot. These effects were compared with those of high-dose MTX (H-MTX). Network pharmacology was employed to construct a compound-target network for RA, based on drug composition, to predict its potential mechanism of action. Flow cytometry, Western Blot, and immunohistochemical analyses in animal models identified multiple inflammatory pathways targeted by LBT to augment the anti-RA effects of MTX.

Results

The study revealed that LBT combined with M-MTX significantly alleviated CIA-induced arthritis without adverse effects. The combination of LBT and M-MTX showed similar or superior efficacy in regulating macrophage polarization, NF-κB, MAPK signaling pathways, and in the suppression of TH-17 expression in proinflammatory cells. These findings suggest that LBT may exert a multi-pathway therapeutic effect in RA treatment. The predicted pharmacological targets and mechanisms align well with this hypothesis.

Conclusion

LBT, when combined with MTX, enhances the anti-RA effect by targeting multiple inflammatory pathways, demonstrating significant therapeutic potential.

Oroxylin A suppresses breast cancer-induced osteoclastogenesis and osteolysis as a natural RON inhibitor

BACKGROUND

Malignant breast cancer cells trigger the over-activation of osteoclast precursor cells, leading to bone loss and severe pain. Targeted inhibition of osteoclast differentiation has emerged as an important strategy for treating bone syndromes induced by breast cancer.

PURPOSE

The objective is to discover natural osteoclast inhibitor to treat osteoclastogenesis and bone destruction induced by breast cancer, and clarify the specific mechanisms.

METHODS

Recepteur d'origine Nantais (RON) protein was employed to search the natural osteoclast inhibitor for breast cancer-induced osteoclastogenesis by molecular docking, molecular dynamics simulation and cellular thermal shift assay (CETSA). In the in vitro experiment, breast cancer MDA-MB-231 cell-conditioned medium (MDA-MB-231 CM) was used to induce osteoclastogenesis in murine bone marrow-derived macrophages (BMMs), aiming to elucidate the effects and mechanisms of the natural osteoclast inhibitor. In the in vivo model, MDA-MB-231 cells was injected into the mouse tibia to evaluate the therapeutic effect of drug on breast cancer-induced bone destruction.

RESULTS

We discovered a significant increase in the expression of RON during MDA-MB-231 CM-induced osteoclast differentiation in vitro. Molecular docking analysis found that oroxylin A (OA), a flavonoid derived from the Chinese medicine Scutellaria baicalensis Georgi, showed binding ability with RON, while its impact and mechanism on breast cancer-induced osteoclastogenesis and osteolysis remains unclear. Molecular dynamics simulation and CETSA further revealed that OA bound directly to the RON protein, and it also decreased RON expression in breast cancer CM-induced osteoclastogenesis. Correspondingly, OA suppressed the MDA-MB-231 CM-induced osteoclastogenesis and bone resorption in vitro. The downstream signals of RON including Src and NFATc1, as well as the osteoclast-specific genes, were downregulated by OA. Of interesting, the suppressive effect of OA on osteoclastogenesis induced by MDA-MB-231 CM was abolished after RON was knocked down by the specific RON-siRNA, this further confirmed that OA showed inhibitory effects on osteoclasts through targeting RON. In addition, we found that OA attenuated MDA-MB-231 cell-induced osteolysis and reduced the number of osteoclasts in vivo.

CONCLUSION

Our results indicate that OA acts as a natural RON inhibitor to suppress breast cancer-induced osteoclastogenesis and osteolysis. This provides new strategy for treating breast cancer-induced bone destruction and related syndromes.

A Review of Advances in Molecular Imaging of Rheumatoid Arthritis: From In Vitro to Clinic Applications Using Radiolabeled Targeting Vectors with Technetium-99m

Rheumatoid arthritis (RA) is a systemic autoimmune disorder caused by inflammation of cartilaginous diarthrodial joints that destroys joints and cartilage, resulting in synovitis and pannus formation. Timely detection and effective management of RA are pivotal for mitigating inflammatory arthritis consequences, potentially influencing disease progression. Nuclear medicine using radiolabeled targeted vectors presents a promising avenue for RA diagnosis and response to treatment assessment. Radiopharmaceutical such as technetium-99m (99mTc), combined with single photon emission computed tomography (SPECT) combined with CT (SPECT/CT), introduces a more refined diagnostic approach, enhancing accuracy through precise anatomical localization, representing a notable advancement in hybrid molecular imaging for RA evaluation. This comprehensive review discusses existing research, encompassing in vitro, in vivo, and clinical studies to explore the application of 99mTc radiolabeled targeting vectors with SPECT imaging for RA diagnosis. The purpose of this review is to highlight the potential of this strategy to enhance patient outcomes by improving the early detection and management of RA.

Mechanistic insights into anti-inflammatory and immunosuppressive effects of plant secondary metabolites and their therapeutic potential for rheumatoid arthritis

The anti-inflammatory and immunosuppressive activities of plant secondary metabolites are due to their diverse mechanisms of action against multifarious molecular targets such as modulation of the complex immune system associated with rheumatoid arthritis (RA). This review discussed and critically analyzed the potent anti-inflammatory and immunosuppressive effects of several phytochemicals and their underlying mechanisms in association with RA in experimental studies, including preliminary clinical studies of some of them. A wide range of phytochemicals including phenols, flavonoids, chalcones, xanthones, terpenoids, alkaloids, and glycosides have shown significant immunosuppressive and anti-inflammatory activities in experimental RA models and a few have undergone clinical trials for their efficacy and safety in reducing RA symptoms and improve patient outcomes. These phytochemicals have potential as safer alternatives to the existing drugs in the management of RA, which possess a wide range of serious side effects. Sufficient preclinical studies on safety and efficacy of these phytochemicals must be performed prior to proper clinical studies. Further studies are needed to address the barriers that have so far limited their human use before the therapeutic potential of these plant-based chemicals as anti-arthritic agents in the treatment of RA is fully realized.

Phlorizin Regulates Synovial Hyperplasia and Inflammation in Rats With Rheumatoid Arthritis by Regulating the mTOR Pathway

BACKGROUND/AIM

Rheumatoid arthritis (RA) is an inflammatory autoimmune disease, and management of it is still a challenge. The present investigation assessed the potential preventive effect of phlorizin on rats with RA.

MATERIALS AND METHODS

A total of 40 healthy Wistar rats were used for this study. Bovine type II collagen and Freund's incomplete adjuvant (1:1 and 1 mg/ml) were administered on days 1 and 8 of the protocol to induce RA in rats; treatment with phlorizin at 60 or 120 mg/kg was started after the 4th week of the protocol, and its effect on inflammation, level of inflammatory cytokines, and expression of proteins were estimated in RA rats. Moreover, an in vitro study was performed on fibroblast-like synoviocytes (FLSs), and the effects of phlorizin on proliferation, apoptosis, and expression of the mechanistic target of rapamycin kinase pathway protein after stimulating these cells with tumor necrosis factor α (TNF-α) were estimated.

RESULTS

The data obtained from the study indicate that phlorizin has the potential to mitigate inflammation and enhance weight management in rats with RA induced by bovine type II collagen (CII). The level of inflammatory cytokines in the serum and the expression of protein kinase B (AKT), phosphatidylinositol-4,5-bisphosphate 3-kinase (PI3K), and mechanistic target of rapamycin kinase (mTOR) proteins in the joint tissue were reduced in phlorizin-treated rats with RA. In this investigation, phlorizin was shown to reverse the histological abnormalities in the joint tissue of rats with RA. The in-vitro study showed that phlorizin reduced proliferation and had no apoptotic effect on TNF-α-stimulated FLSs. Expression of AKT, PI3K, and mTOR proteins was also down-regulated in phlorizin-treated TNF-α-stimulated FLSs.

CONCLUSION

Phlorizin protects against inflammation and reduces injury to synovial tissues in RA by modulating the AKT/PI3K/mTOR pathway.

Subchondral osteoclasts and osteoarthritis: new insights and potential therapeutic avenues

Osteoarthritis (OA) is the most common joint disease, and good therapeutic results are often difficult to obtain due to its complex pathogenesis and diverse causative factors. After decades of research and exploration of OA, it has been progressively found that subchondral bone is essential for its pathogenesis, and pathological changes in subchondral bone can be observed even before cartilage lesions develop. Osteoclasts, the main cells regulating bone resorption, play a crucial role in the pathogenesis of subchondral bone. Subchondral osteoclasts regulate the homeostasis of subchondral bone through the secretion of degradative enzymes, immunomodulation, and cell signaling pathways. In OA, osteoclasts are overactivated by autophagy, ncRNAs, and Rankl/Rank/OPG signaling pathways. Excessive bone resorption disrupts the balance of bone remodeling, leading to increased subchondral bone loss, decreased bone mineral density and consequent structural damage to articular cartilage and joint pain. With increased understanding of bone biology and targeted therapies, researchers have found that the activity and function of subchondral osteoclasts are affected by multiple pathways. In this review, we summarize the roles and mechanisms of subchondral osteoclasts in OA, enumerate the latest advances in subchondral osteoclast-targeted therapy for OA, and look forward to the future trends of subchondral osteoclast-targeted therapies in clinical applications to fill the gaps in the current knowledge of OA treatment and to develop new therapeutic strategies.

Isorhamnetin Downregulates MMP2 and MMP9 to Inhibit Development of Rheumatoid Arthritis through SRC/ERK/CREB Pathway

OBJECTIVE

To investigate the effect of isorhamnetin on the pathology of rheumatoid arthritis (RA).

METHODS

Tumor necrosis factor (TNF)- α -induced fibroblast-like synoviocytes (FLS) was exposed to additional isorhamnetin (10, 20 and 40 µ mol/L). Overexpression vectors for matrix metalloproteinase-2 (MMP2) or MMP9 or SRC were transfected to explore their roles in isorhamnetin-mediated RA-FLS function. RA-FLS viability, migration, and invasion were evaluated. Moreover, a collagen-induced arthritis (CIA) rat model was established. Rats were randomly divided to sham, CIA, low-, medium-, and high-dosage groups using a random number table (n=5 in each group) and administed with normal saline or additional isorhamnetin [2, 10, and 20 mg/(kg·day)] for 4 weeks, respectively. Arthritis index was calculated and synovial tissue inflammation was determined in CIA rats. The levels of MMP2, MMP9, TNF-α, interleukin-6 (IL-6), and IL-1 β, as well as the phosphorylation levels of SRC, extracellular regulated kinase (ERK), and cyclic adenosine monophosphate response element-binding (CREB), were detected in RA-FLS and synovial tissue. Molecular docking was also used to analyze the binding of isorhamnetin to SRC.

RESULTS

In in vitro studies, isorhamnetin inhibited RA-FLS viability, migration and invasion (P<0.05). Isorhamnetin downregulated the levels of MMP2, MMP9, TNF-α, IL-6, and IL-1 β in RA-FLS (P<0.05). The overexpression of either MMP2 or MMP9 reversed isorhamnetin-inhibited RA-FLS migration and invasion, as well as the levels of TNF-α, IL-6, and IL-1 β (P<0.05). Furthermore, isorhamnetin bound to SRC and reduced the phosphorylation of SRC, ERK, and CREB (P<0.05). SRC overexpression reversed the inhibitory effect of isorhamnetin on RA-FLS viability, migration and invasion, as well as the negative regulation of MMP2 and MMP9 (P<0.05). In in vivo studies, isorhamnetin decreased arthritis index scores (P<0.05) and alleviated synovial inflammation. Isorhamnetin reduced the levels of MMP2, MMP9, TNF-α, IL-6, and IL-1 β, as well as the phosphorylation of SRC, ERK, and CREB in synovial tissue (P<0.05). Notably, the inhibitory effect of isorhamnetin was more pronounced at higher concentrations (P<0.05).

CONCLUSION

Isorhamnetin exhibited anti-RA effects through modulating SRC/ERK/CREB and MMP2/MMP9 signaling pathways, suggesting that isorhamnetin may be a potential therapeutic agent for RA.

Xuetongsu attenuates bone destruction in collagen-induced arthritis mice by inhibiting osteoclast differentiation and promoting osteoclast apoptosis

Tujia ethnomedicine Xuetong (the stems of Kadsura heteroclita) have been widely used in folk for rheumatoid arthritis (RA), which can alleviate rheumatic pain through liquor soaking in folk. In this study, we aimed to evaluate the pharmacological effects and underlying mechanism of Xuetongsu (a key chemical component of Xuetong) on bone destruction. In our previous study, it was found that Xuetong extract can reduce adjuvant arthritic rats paw swelling and inhibit inflammatory factors in serum. Furthermore, Xuetongsu has been demonstrated to inhibit the proliferation of fibroblast-like synoviocytes, but its potential to inhibit bone destruction has not been explored. To address this, we employed the STRING database to predict protein interactions and utilized Autodock software to simulate the binding of Xuetongsu to target proteins. In this study, administration of Xuetongsu significantly alleviated paw swelling and bone destruction in C57BL/6 mice with collagen-induced arthritis (CIA). Mechanistic studies have indicated that Xuetongsu promotes apoptosis of mature osteoclasts in joint tissues by activating Caspase-3 and Bax, while inhibiting Bcl-2. Additionally, Xuetongsu inhibits osteoclast differentiation by suppressing RANKL, RANK, P-NF-κB, and NFATc1, and reduces bone resorption activity by inhibiting MMP-9, CTSK, and TRAP. Importantly, Xuetongsu exhibits good biocompatibility in major organs of mice. In summary, Xuetongsu has the potential to treat bone destruction by promoting apoptosis of mature osteoclasts, inhibiting osteoclast differentiation, and reducing bone resorption. This study reveals the pharmacological effects of Xuetongsu and its mechanism of action, which may contribute to the development of novel approaches for treating RA.

Distinct cross talk of IL-17 & TGF-β with the immature CD11c+ TRAF6(-/-) -null myeloid dendritic cell-derived osteoclast precursor (mDDOCp) may engage signaling toward an alternative pathway of osteoclastogenesis for arthritic bone loss in vivo

BACKGROUND

Dendritic cells (DCs), though borne heterogeneous, are the most potent antigen-presenting cells, whose critical functions include triggering antigen-specific naïve T-cell responses and fine-tuning the innate versus adaptive immunity at the osteo-immune and/or mucosal mesenchyme interface. We previously reported that immature myeloid-CD11c+ DCs/mDCs may act like osteoclast (OC) precursors (OCp/mDDOCp) capable of developing into functional OCs via an alternative pathway of inflammation-induced osteoclastogenesis; however, what are their contribution and signaling interactions with key osteotropic cytokines (i.e., interleukin-17 [IL-17] and transforming growth factor-β [TGF-β]) to bearing such inflammatory bone loss in vivo remain unclear to date.

METHODS

Herein, we employed mature adult bone marrow-reconstituted C57BL/6 TRAF6(-/-) -null chimeras without the classical monocyte/macrophage (Mo/Mϕ)-derived OCs to address their potential contribution to OCp/mDDOCp-mediated osteoclastogenesis in the chicken type-II-collagen (CC-II)-induced joint inflammation versus arthritic bone loss and parallel associations with the double-positive CD11c+ TRAP+ TRAF6-null(-/-)  DC-like OCs detected in vivo via the quantitative dual-immunohistochemistry and digital histomorphometry for analyses.

RESULTS

The resulting findings revealed the unrecognized novel insight that (i) immature myeloid-CD11c+ TRAF6(-/-) TRAP+ DC-like OCs were involved, co-localized, and strongly associated with joint inflammation and bone loss, independent of the Mo/Mϕ-derived classical OCs, in CC-II-immunized TRAF6(-/-) -null chimeras, and (ii) the osteotropic IL-17 may engage distinct crosstalk with CD11c+ mDCs/mDDOCp before developing the CD11c+ TRAP+ TRAF6(-/-) OCs via a TGF-β-dependent interaction toward inflammation-induced arthritic bone loss in vivo.

CONCLUSION

These results confirm and substantiate the validity of TRAF6(-/-) -null chimeras to address the significance of immature mCD11c+ TRAP+ DC-like OCs/mDDOCp subset for an alternative pathway of arthritic bone loss in vivo. Such CD11c+ mDCs/mDDOCp-associated osteoclastogenesis through the step-wise twist-in-turns osteo-immune cross talks are thereby theme highlighted to depict a summative re-visitation proposed.

Research Progress on Immunomodulatory Effects of Poly (Lactic-co- Glycolic Acid) Nanoparticles Loaded with Traditional Chinese Medicine Monomers

Immunomodulatory mechanisms are indispensable and key factors in maintaining the balance of the environment in humans. When the immune function of the immune system is impaired, autoimmune diseases occur. Excessive body fatigue, natural aging of the human body, malnutrition, genetic factors and other reasons cause low immune function, due to which the body is prone to being infected by bacteria or cancer. Clinically, the existing therapeutic drugs still have problems such as high toxicity, long treatment cycle, drug resistance and high price, so we still need to explore and develop a high efficiency and low toxicity drug. Poly(lactic-co-glycolic acid) (PLGA) refers to a nontoxic polymer compound that exhibits excellent biocompatibility. Traditional Chinese medicine (TCM) monomers come from natural plants, and have the characteristics of high efficiency and low toxicity. Applying PLGA to TCM monomers can make up for the defects of traditional dosage forms, improve bioavailability, reduce the frequency and dosage of drug use, and reduce toxicity and side effects, thus having the characteristics of sustained release and targeting. Accordingly, PLGA nanoparticles loaded with TCM monomers have been the focus of development. The previous research on drug loading advantages, preparation methods, and immune regulation of TCM PLGA nanoparticles is summarized in the following sections.

A Review of Proposed Mechanisms in Rheumatoid Arthritis and Therapeutic Strategies for the Disease

Rheumatoid arthritis (RA) is characterized by synovial edema, inflammation, bone and cartilage loss, and joint degradation. Patients experience swelling, stiffness, pain, limited joint movement, and decreased mobility as the condition worsens. RA treatment regimens often come with various side effects, including an increased risk of developing cancer and organ failure, potentially leading to mortality. However, researchers have proposed mechanistic hypotheses to explain the underlying causes of synovitis and joint damage in RA patients. This review article focuses on the role of synoviocytes and synoviocytes resembling fibroblasts in the RA synovium. Additionally, it explores the involvement of epigenetic regulatory systems, such as microRNA pathways, silent information regulator 1 (SIRT1), Peroxisome proliferatoractivated receptor-gamma coactivator (PGC1-α), and protein phosphatase 1A (PPM1A)/high mobility group box 1 (HMGB1) regulators. These mechanisms are believed to modulate the function of receptors, cytokines, and growth factors associated with RA. The review article includes data from preclinical and clinical trials that provide insights into potential treatment options for RA.

Ondansetron or beta-sitosterol antagonizes inflammatory responses in liver, kidney, lung and heart tissues of irradiated arthritic rats model

BACKGROUND

Rheumatoid arthritis (RA) is a chronic inflammatory autoimmune disorder mainly affecting joints, yet the systemic inflammation can influence other organs and tissues. The objective of this study was to unravel the ameliorative capability of Ondansetron (O) or β-sitosterol (BS) against inflammatory reactions and oxidative stress that complicates Extra-articular manifestations (EAM) in liver, kidney, lung, and heart of arthritic and arthritic irradiated rats.

METHODS

This was accomplished by exposing adjuvant-induced arthritis (AIA) rats to successive weekly fractions of total body γ-irradiation (2 Gray (Gy)/fraction once per week for four weeks, up to a total dose of 8 Gy). Arthritic and/or arthritic irradiated rats were either treated with BS (40 mg/kg b.wt. /day, orally) or O (2 mg/kg) was given ip) or were kept untreated as model groups.

RESULTS

Body weight changes, paw circumference, oxidative stress indices, inflammatory response biomarkers, expression of Janus kinase-2 (JAK-2), Signal transducer and activator of transcription 3 (STAT3), high mobility group box1 (HMGB1), and nuclear factor kappa-light-chain-enhancer of activated B cells (NF-κB), as well as pro- and anti-inflammatory mediators in the target organs, besides histopathological examination of ankle joints and extra-articular tissues. Treatment of arthritic and/or arthritic irradiated rats with BS or O powerfully alleviated changes in body weight gain, paw swelling, oxidative stress, inflammatory reactions, and histopathological degenerative alterations in articular and non-articular tissues.

CONCLUSION

The obtained data imply that BS or O improved the articular and EAM by regulating oxidative and inflammatory indices in arthritic and arthritic irradiated rats.

Time- and Concentration-Dependent Stimulation of Oxidative Stress in Chondrocytes by Intracellular Soluble Urate

BACKGROUND

Gout could result in irreversible bone erosion, and chondrocyte might be involved in the process. Increased soluble urate is the early stage of gout and is strongly oxidative.

OBJECTIVE

To explore the effect of intracellular urate on the oxidative status of chondrocytes.

METHODS

A chondrocyte model was used. Serial concentrations of exogenous urate were incubated with chondrocytes for increasing amounts of time. Reactive oxygen species (ROS), oxidant, and anti-oxidant molecules were measured with biochemical assays, rt-PCR, and western blot. A urate transport inhibitor and oxidative inhibitors were used to confirm the effect of exogenous urate.

RESULTS

All concentrations of exogenous urate stimulated the production of ROS in a time- and concentration-dependent manner, as well as oxidant molecules, including hydrogen peroxide (H2O2), nicotinamide adenine dinucleotide phosphate (NADPH) oxidase, nitric oxide (NO) inducible nitric oxide synthase (iNOS), and these effects, could be inhibited by oxidant inhibitors. However, anti-oxidant molecules, including acidic leucine-rich nuclear phosphoprotein-32A (ANP32A), ataxia-telangiectasia mutated (ATM), heme oxygenase-1 (HO-1), and the transcription factor nuclear factor erythroid 2 (NF-E2)-related (Nrf2), was decreased by high concentrations of exogenous urate after prolonged incubation, but not by low to medium concentrations of exogenous urate. By inhibiting soluble urate trafficking, benzbromarone significantly suppressed the effect of urate stimulus on the oxidant and anti-oxidant molecules.

CONCLUSION

Intracellular soluble urate could regulate chondrocyte redox balance in a time and concentration-dependent manner, and would be a target for regulating and protecting chondrocyte function in the early gout stage.

The study of serum muscarinic acetylcholine receptor subtype 3 (m3AChR)-Specific autoantibodies level in rheumatoid arthritis patients with secondary sjogren syndrome

BACKGROUND

Dry eyes and mouth are symptoms of Sjogren syndrome, which can occur on its own and be referred to as primary Sjogren syndrome or in conjunction with other rheumatic diseases like rheumatoid arthritis and be referred to as secondary Sjogren syndrome. Anti-muscarinic type 3 receptors have been linked to neurological issues as well as secretory dysfunction in Sjogren patients. Consequently, the purpose of this study is to determine the serum level of muscarinic acetylcholine receptor subtype 3 (m3AChR)-specific autoantibodies in rheumatoid arthritis (RA) patients and evaluate its relationship to disease activity, functional disability, and to study its role in the development of secondary Sjogren syndrome manifestations in those patients.

METHODS

In this cross-sectional study, 30 RA patients with secondary Sjogren syndrome signs and 30 RA patients without secondary Sjogren syndrome manifestations were included, along with 30 healthy volunteers who were aged, and sex matched as controls. All participants underwent thorough clinical examination, evaluation of disease activity using the DAS28 score, assessment of functional status using the modified health assessment questionnaire (MHAQ), and evaluation of the serum level of (m3AChR) by (ELISA).

RESULTS

When compared to RA patients without secondary Sjogren syndrome and healthy controls (20.09 ± 4.24, 18.36 ± 3.59 ng/ml respectively), the serum level of m3AChR antibodies among 30 RA patients with secondary Sjogren syndrome considerably increased (mean 25.98 ± 4.81 ng/ml).Analysis of the m3AChR's (ROC)-curve revealed that the three groups under study differed significantly (P < 0.001), with the AUC (0.806), cutoff (> 22.63ng/ml), sensitivity (73.33%), and specificity (86.67%) all exceeding the threshold. Additionally, there was a significant positive connection between the serum level of m3AChR and the following variables (P < 0.05): DAS scores, MHAQ score, number of tender & swollen joints, and acute phase reactants.

CONCLUSION

Autoantibodies against m3AChR may be one of the serum components involved in the pathophysiology of secondary Sjogren syndrome in RA patients, and because of their high sensitivity and specificity, they can be utilized as a diagnostic marker in these individuals.

The universal presence of poor prognostic factors based on EULAR recommendations: A real-world study in 1164 Chinese RA patients

INTRODUCTION

Poor prognostic factors (PPFs) have been used in assisting therapeutic decision-making in rheumatoid arthritis (RA). There are no standard lists of PPFs for RA, and whether PPFs can guide RA treatment remains controversial.

OBJECTIVES

To analyze the profile of PPF based on EULAR recommendations in RA patients and explore the necessity of considering these PPFs in adjusting therapy.

METHODS

Prognostic factors including erythrocyte sedimentation rate (ESR) and C-reactive protein (CRP), rheumatoid factor (RF), anti-citrullinated protein antibody (ACPA), swollen joint count (SJC), early erosions, and response to first conventional synthetic disease-modifying anti-rheumatic drugs (csDMARD) therapy in 1164 RA patients were collected. The profile of PPFs was graphically displayed. The correlation between different PPFs was analyzed.

RESULTS

Elevated ESR/CRP was presented in 746 (64%) patients, and positive RF/ACPA in 1021 (88%) patients. Two hundred and sixty-eight (23%) patients had≥4 swollen joints. Three hundred (26%) patients had moderate or high disease activity (MDA/HDA) despite csDMARD therapy. Failure of≥2 csDMARDs was found in 30% (224/740) of patients. One hundred and fifty-three out of 459 (33%) patients had early bone erosions, usually coexisted with other PPFs. Ninety-seven percent of RA patients had≥1 PPF. Being MDA/HDA≥3 months was significantly correlated with elevated ESR/CRP or high SJC, however uncorrelated with RF/ACPA positivity or early erosions.

CONCLUSIONS

PPFs are universally present in RA patients. The reasonability of guiding treatment strategies just based on the presence or absence of PPFs requires further investigation. The categories of PPFs can be simplified and the role of different PPFs combinations in guiding treatment needs to be explored.

GCSB-5 regulates inflammatory arthritis and pain by modulating the mitogen-activated protein kinase signaling pathway in a murine model of rheumatoid arthritis

Objectives

This study aimed to determine whether GCSB-5 has anti-inflammatory and antinociceptive effects in mice with collagen-induced arthritis (CIA), an animal model of rheumatoid arthritis (RA), and investigate the influence of GCSB-5 on the mitogen-activated protein kinase (MAPK) pathway.

Materials and methods

The experimental animal study was designed to include five groups: CIA mice treated with GCSB-5 (300 mg/kg), GCSB-5 (600 mg/kg), celecoxib (60 mg/kg), or saline for four weeks, and nontreated control mice. The clinical severity of arthritis was scored. Nociceptive thresholds were measured by using a von Frey dynamic plantar analgesimeter. The MAPK pathway was evaluated in mouse synovium. The expression of channels associated with pain signaling was assessed by western blot and immunohistochemical staining.

Results

GCSB-5 treatment diminished the severity of clinical arthritis and increased the nociceptive threshold in mice with CIA. Celecoxib, a positive control drug, also showed comparable changes. Clinical arthritis scores were inversely related to mechanical thresholds. GCSB-5 administration decreased the levels of anti-type II collagen antibody and inflammatory cytokines in the sera of mice with CIA. Furthermore, ERK, p38 MAPK, and JNK phosphorylation were downregulated and TRPV1 and ASIC3 expression were decreased in the synovium of GCSB-5-treated mice compared to salinetreated mice. Interleukin-6-induced TRPV1 and ASIC3 upregulation were also inhibited by GCSB-5 in human RA fibroblast-like synoviocytes in vitro.

Conclusion

GCSB-5 decreased inflammatory arthritis and pain in a murine model of RA. The results present evidence that GCSB-5 may be beneficial for relieving pain as well as decreasing inflammation in autoimmune arthritis, such as RA.

Pharmacological mechanisms of sinomenine in anti-inflammatory immunity and osteoprotection in rheumatoid arthritis: A systematic review

BACKGROUND

Sinomenine (SIN) is the main pharmacologically active component of Sinomenii Caulis and protects against rheumatoid arthritis (RA). In recent years, many studies have been conducted to elucidate the pharmacological mechanisms of SIN in the treatment of RA. However, the molecular mechanism of SIN in RA has not been fully elucidated.

PURPOSE

To summarize the pharmacological effects and molecular mechanisms of SIN in RA and clarify the most valuable regulatory mechanisms of SIN to provide clues and a basis for basic research and clinical applications.

METHODS

We systematically searched SciFinder, Web of Science, PubMed, China National Knowledge Internet (CNKI), the Wanfang Databases, and the Chinese Scientific Journal Database (VIP). We organized our work based on the PRISMA statement and selected studies for review based on predefined selection criteria.

OUTCOME

After screening, we identified 201 relevant studies, including 88 clinical trials and 113 in vivo and in vitro studies on molecular mechanisms. Among these studies, we selected key results for reporting and analysis.

CONCLUSIONS

We found that most of the known pharmacological mechanisms of SIN are indirect effects on certain signaling pathways or proteins. SIN was manifested to reduce the release of inflammatory cytokines such as Tumor necrosis factor-α (TNF-α), Interleukin-6 (IL-6), and IL-1β, thereby reducing the inflammatory response, and apparently blocking the destruction of bone and cartilage. The regulatory effects on inflammation and bone destruction make SIN a promising drug to treat RA. More notably, we believe that the modulation of α7nAChR and the regulation of methylation levels at specific GCG sites in the mPGES-1 promoter by SIN, and its mechanism of directly targeting GBP5, certainly enriches the possibilities and the underlying rationale for SIN in the treatment of inflammatory immune-related diseases.

Correlation analysis and clinical significance of Musculoskeletal Ultrasound semi-quantitative grading with bone salt metabolism, Rheumatoid factor and Erythrocyte Sedimentation rate in patients with Rheumatoid Arthritis

Objective

To determine the correlation and clinical significance of musculoskeletal ultrasound semi-quantitative grading with bone salt metabolism, rheumatoid factor and erythrocyte sedimentation rate (ESR) in patients with rheumatoid arthritis.

Methods

This is a clinical comparative study. A total of 240 patients with rheumatoid arthritis admitted to Baoding NO.1 Central Hospital were selected according to the DAS28 score of rheumatoid arthritis, and were divided into four groups, with 60 cases in each group from May 2020 to May 2022. The differences and correlation of musculoskeletal ultrasound semi-quantitative grading, bone metabolism indicators, erythrocyte sedimentation rate and rheumatoid factor among the four groups were statistically analyzed.

Results

The scores of bone erosion, synovial hyperplasia, joint effusion and intrasynovial blood flow in Group-H were significantly higher than those in Group-R, L and M, with statistically significant differences(p=0.00). The procollagen Type-1 N-terminal propeptide(P1NP), bone-specific alkaline phosphatase(BALP) and osteoprotegerin(OPG) in Group-H were significantly lower than those in Group-R, L and M, with statistically significant differences(p=0.00); The tartrate-resistant acid phosphatase(TRAC) in Group-H was significantly higher than that in Group-R, L and M, with a statistically significant difference(p=0.00). The levels of RF and ESR in Group-H were significantly higher than those in Group-R, L and M, with statistically significant differences(p=0.00).

Conclusion

Musculoskeletal ultrasound semi-quantitative grading is correlated with the level of bone salt metabolism, rheumatoid factor and ESR in patients with rheumatoid arthritis. It can be combined with laboratory examination to objectively judge the severity of the course of rheumatoid arthritis.

Aberrant Activation of Immune and Non-Immune Cells Contributes to Joint Inflammation and Bone Degradation in Rheumatoid Arthritis

Abnormal activation of multiple immune and non-immune cells and proinflammatory factors mediate the development of joint inflammation in genetically susceptible individuals. Although specific environmental factors like smoking and infections are associated with disease pathogenesis, until now, we did not know the autoantigens and arthritogenic factors that trigger the initiation of the clinical disease. Autoantibodies recognizing specific post-translationally modified and unmodified antigens are generated and in circulation before the onset of the joint disease, and could serve as diagnostic and prognostic markers. The characteristic features of autoantibodies change regarding sub-class, affinity, glycosylation pattern, and epitope spreading before the disease onset. Some of these antibodies were proven to be pathogenic using animal and cell-culture models. However, not all of them can induce disease in animals. This review discusses the aberrant activation of major immune and non-immune cells contributing to joint inflammation. Recent studies explored the protective effects of extracellular vesicles from mesenchymal stem cells and bacteria on joints by targeting specific cells and pathways. Current therapeutics in clinics target cells and inflammatory pathways to attenuate joint inflammation and protect the cartilage and bones from degradation, but none cure the disease. Hence, more basic research is needed to investigate the triggers and mechanisms involved in initiating the disease and relapses to prevent chronic inflammation from damaging joint architecture.

Cartilage and bone loss in premenopausal women with rheumatoid arthritis: Radiological and laboratory assessments

INTRODUCTION

To investigate the radiological and laboratory features of bone and cartilage losses in premenopausal women with rheumatoid arthritis (RA).

METHODS

This case-control study is the continuation of a study that was conducted on 48 women with RA and 48 matched healthy volunteers. All RA patients were previously subjected to clinical examination, disease activity assessment using the 28-joint Disease Activity Score (DAS28) and Clinical Disease Activity Index (CDAI), serological tests, dual-energy X-ray absorptiometry measuring bone mineral density (BMD), and plain X-ray of both hands. Added to these, matrix metalloproteinase 3 (MMP-3) and cartilage oligomeric matrix protein (COMP) were measured by enzyme-linked immunosorbent assay.

RESULTS

There were statistically significant differences between patients and controls regarding COMP and MMP-3, being higher in patients (p < .001). COMP and MMP-3 have significant positive correlation with serum levels of anti-cyclic citrullinated peptide (anti-CCP) and anti-carbamylated protein (anti-CarP). The original Sharp erosion score was positively correlated with the serum level of the studied antibodies and disease duration, but no significant correlation was found with either COMP, MMP-3, or DAS-28. Spine BMD and Z score were negatively correlated with disease activity and anti-CarP. There were significant positive relationhsips between indices of local cartilage and bone loss and the indices of systemic bone loss. MMP-3 had no correlation with indices of local cartilage and bone loss and disease activity scores.

CONCLUSIONS

The pathogenic mechanism of hand joint damage involved the three studied autoantibodies namely, rheumatoid factor, anti-CCP and anti-CarP antibodies. Anti-CarP antibody was involved in the reduction of BMD of the spine. The association between systemic osteoporosis and hand joint damage pointed to a common pathogenic mechanism.

In vitro inhibitory effect of zingerone on TNFα-stimulated fibroblast-like synoviocytes

Targeting Fibroblast-like synoviocytes (FLSs) is an attractive complementary approach for RA therapy. This study aimed to investigate the inhibitory effects of zingerone on TNFα-induced arthritic FLSs. MTS, EdU, wound healing, DHE staining and real-time PCR were used to determine the effects of zingerone on the destructive behaviors of arthritic FLSs induced by TNFα. Western blot analysis was used to analyze cell signaling pathways. Zingerone treatment significantly inhibited TNFα-induced proliferation, migration, ROS formation and pro-inflammatory cytokines expression of FLSs. Molecular mechanism studies revealed that zingerone could suppress TNFα-induced activations of MAPKs (ERK, JNK and p38) in arthritic FLSs. Zingerone attenuated pathological features of FLSs via MAPKs pathways, indicating its potential as a complementary or alternative drug for RA therapy.

Anti-Arthritic and Immunomodulatory Potential of Methanolic, n-Hexane, and Ethyl Acetate Fractions of Bark of Acacia modesta on Complete Freund's Adjuvant-Induced Arthritis in Rats

Rheumatoid arthritis is an autoimmune disorder and topic of interest for researchers due to its increasing frequency and limited treatment. Acacia modesta Wall is known to treat rheumatic disorders in the traditional system of medicinal plants. Traditional medicines are still required for the treatment of this disease due to the large number of side-effects caused by commercial medicines. In the current study, the antiarthritic potential of methanolic extract (AM-metha), n-hexane (AM-hexa) fraction, and ethyl acetate (AM-etha) fraction of the bark of A. modesta against a complete Freund's adjuvant rat model was evaluated. Evaluation using a digital plethysmometer, macroscopic evaluation, and histopathological evaluation were conducted to determine the paw volume and arthritic scoring. ELISA was performed to assess the PGE2 levels. RT-PCR was used to evaluate the expression levels of MMP2, MMP3, MMP9, NF-κB, IL6, IL1β, TNFα, and VEGF. Biochemical and hematological analyses were also conducted. GC/MS was also carried out to analyze the presence of medicinal compounds. The data revealed a marked reduction in the paw volume, arthritic scoring, and histopathological parameters, indicating the anti-arthritic potential of the plant. Treatment with plant extracts and fractions markedly down-regulated MMP2, MMP3, MMP9, NF-κB, IL6, IL1β, TNFα, and VEGF levels. Similarly, PGE2 levels were also found to be ameliorated in the treatment groups, indicating the immunomodulatory property of plant bark. Plant treatment nearly normalized hematological parameters such as counts of WBCs, RBCs, and platelets, along with Hb content, thereby validating the anti-arthritic activity. GC/MS analysis disclosed the presence of strong anti-inflammatory compounds such as lupeol, oleic acid, and squalene. The study showed that A. modesta possesses anti-arthritic and immunomodulatory potential linked to significant down-regulation of pro-inflammatory and inflammatory biomarkers.

Therapeutic potential of Coptis chinensis for arthritis with underlying mechanisms

Arthritis is a common degenerative disease of joints, which has become a public health problem affecting human health, but its pathogenesis is complex and cannot be eradicated. Coptis chinensis (CC) has a variety of active ingredients, is a natural antibacterial and anti-inflammatory drug. In which, berberine is its main effective ingredient, and has good therapeutic effects on rheumatoid arthritis (RA), osteoarthritis (OA), gouty arthritis (GA). RA, OA and GA are the three most common types of arthritis, but the relevant pathogenesis is not clear. Therefore, molecular mechanism and prevention and treatment of arthritis are the key issues to be paid attention to in clinical practice. In general, berberine, palmatine, coptisine, jatrorrhizine, magnoflorine and jatrorrhizine hydrochloride in CC play the role in treating arthritis by regulating Wnt1/β-catenin and PI3K/AKT/mTOR signaling pathways. In this review, active ingredients, targets and mechanism of CC in the treatment of arthritis were expounded, and we have further explained the potential role of AHR, CAV1, CRP, CXCL2, IRF1, SPP1, and IL-17 signaling pathway in the treatment of arthritis, and to provide a new idea for the clinical treatment of arthritis by CC.

Effects of Etanercept and Adalimumab on Serum Levels of Cartilage Remodeling Markers in Women with Rheumatoid Arthritis

Tumor necrosis factor α inhibitor (TNFαI) therapy is associated with a significant inhibition of radiographic progression, resulting in improved physical function and quality of life among patients with rheumatoid arthritis (RA). The mechanism by which TNFαI prevent joint destruction is still unknown. In this study, the effect of 15-month anti-TNF-α therapy in combination with methotrexate on circulating levels of biochemical markers of cartilage turnover in female RA patients was assessed. Serum levels of collagen type II C-terminal cleavage neoepitope (C2C), C-terminal propeptide of type II collagen (PIICP), cartilage oligomeric matrix protein (COMP), and matrix metalloproteinase-3 (MMP-3) were evaluated using immunoassays at baseline and 15 months after the start of TNFαI treatment. Baseline COMP, C2C, and MMP-3 levels and C2C/PIICP ratios were significantly higher in women with RA compared with those observed in the healthy subjects. No differences in PIICP levels between the controls and the women with RA were observed. After 15 months of TNFαI treatment, serum levels of C2C, COMP, and MMP-3 decreased, whereas the levels of PIICP increased but were still not different from those of the controls. These changes were accompanied by significantly reduced C2C/PIICP ratios. Before the start of TNFαI therapy, serum levels of COMP significantly correlated with the patients' ages (p < 0.05) and their 28-joint disease activity score values based on their erythrocyte sedimentation rates (DAS28-ESR; p < 0.05). Moreover, multiple linear regression analysis showed that baseline COMP levels retained a significant association with DAS28-ESR value (β = 287.74, p = 0.022, R2 model = 0.25) after model adjustments. The largest area under the ROC curve was obtained for C2C/PIICP ratios (AUC: 0.830, 95% CI: 0.727-0.932, p < 0.001). Our results suggest that long-term anti-TNF-α therapy combined with MTX has a beneficial effect on cartilage remodeling that is associated with clinical improvement among RA patients. Serum C2C/PIICP ratios may help to monitor the effectiveness of anti-TNF-α treatment among RA patients.

Multifunctional Janus Nanoplatform for Efficiently Synergistic Theranostics of Rheumatoid Arthritis

Progress has been made in the application of nanomedicine in rheumatoid arthritis (RA) treatment. However, the whole process of monitoring and treatment of RA remains a formidable challenge due to the complexity of the chronic autoimmune disease. In this study, we develop a Janus nanoplatform (denoted as Janus-CPS) composed of CeO₂-Pt nanozyme subunit on one side and periodic mesoporous organosilica (PMO) subunit on another side for simultaneous early diagnosis and synergistic therapy of RA. The Janus nanostructure, which enables more active sites to be exposed, enhances the reactive oxygen species scavenging capability of CeO₂-Pt nanozyme subunit as compared to their core-shell counterpart. Furthermore, micheliolide (MCL), an extracted compound from natural plants with anti-osteoclastogenesis effects, is loaded into the mesopores of PMO subunit to synergize with the anti-inflammation effect of nanozymes for efficient RA treatment, which has been demonstrated by in vitro cellular experiments and in vivo collagen-induced arthritis (CIA) model. In addition, by taking advantage of the second near-infrared window (NIR-II) fluorescent imaging, indocyanine green (ICG)-loaded Janus-CPS exhibits desirable effectiveness in detecting RA lesions at a very early stage. It is anticipated that such a Janus nanoplatform may offer an alternative strategy of functional integration for versatile theranostics.

Pathogenesis of rheumatoid arthritis and its treatment with anti-inflammatory natural products

Introduction Rheumatoid arthritis (RA) is a common autoimmune disease across the globe that is chronic and systemic as well. The disease is linked with autoantibodies and is inflammatory, eventually targeting several molecules along with certain modified self-epitopes. The disease majorly affects the joints of an individual. Rheumatoid arthritis is manifested clinically by polyarthritis linked with the dysfunction of the joints. This chiefly affects the synovial joint lining and is linked with progressive dysfunction, premature death, along with socioeconomic implications. The macrophage activation, along with the activation of certain defense cells, results in a response to self-epitopes that helps in providing a better understanding of the disease pathogenesis.  Material and methodology For this review article, papers have been retrieved and reviewed from database including PubMed, Scopus and Web of science. Relevant papers were taken fulfilling the criteria for writing this review article. Results This has resulted in the establishment of several new therapeutic techniques that serve as potential inhibitors of such cells. Researchers have gained an interest in understanding this disease to provide strategies for treatment in the last two decades. This also includes recognition followed by the treatment of the disease at its early stages. Various allopathic treatment approaches often have chronic and toxic teratogenic effects. However, to avoid this issue of toxicity followed by side effects, certain medicinal plants have been used in treating RA.  Conclusion Medicinal plants possess active phytoconstituents that entail antioxidants as well as anti-inflammatory properties, making them a helpful alternative to allopathic drugs that are often linked with highly toxic effects. This review paper entails a thorough discussion of the epidemiology, pathophysiology, diagnosis, and management of RA. The paper will also focus on the use of herbal plants in the treatment of the disease to avoid the side effects that generally occur in allopathic treatment.

Resveratrol-induced SIRT1 activation inhibits glycolysis-fueled angiogenesis under rheumatoid arthritis conditions independent of HIF-1α

OBJECTIVE

This study investigated the impacts of SIRT1 activation on rheumatoid arthritis (RA)-related angiogenesis.

METHODS

HUVECs were cultured by different human serum. Intracellular metabolites were quantified by UPLC-MS. Next, HUVECs and rat vascular epithelial cells under different inflammatory conditions were treated by a SIRT1 agonist resveratrol (RSV). Cytokines and biochemical indicators were detected by corresponding kits. Protein and mRNA expression levels were assessed by immunoblotting and PCR methods, respectively. Angiogenesis capabilities were evaluated by migration, wound-healing and tube-formation experiments. To down-regulate certain signals, gene-specific siRNA were applied.

RESULTS

Metabolomics study revealed the accelerated glycolysis in RA serum-treated HUVECs. It led to ATP accumulation, but did not affect GTP levels. RSV inhibited pro-angiogenesis cytokines production and glycolysis in both the cells, and impaired the angiogenesis potentials. These effects were mimicked by an energy metabolism interrupter bikini in lipopolysaccharide (LPS)-primed HUVECs, largely independent of HIF-1α. Both RSV and bikinin can inhibit the activation of the GTP-dependent pathway Rho/ROCK and reduce VEGF production. Abrogation of RhoA signaling reinforced HIF-1α silencing-brought changes in LPS-stimulated HUVECs, and overshadowed the anti-angiogenesis potentials of RSV.

CONCLUSION

Glycolysis provides additional energy to sustain Rho/ROCK activation in RA subjects, which promotes VEGF-driven angiogenesis and can be inhibited by SIRT1 activation.

Blocking prokineticin receptors attenuates synovitis and joint destruction in collagen-induced arthritis

Rheumatoid arthritis (RA) is a chronic inflammatory disease mediated by an interdependent network of proinflammatory molecules such as chemokines. Prokineticin 2 (PK2) is a chemokine-like peptide that modulates nociceptive threshold and immuno-inflammatory processes via two G-protein-linked receptors, prokineticin receptor 1 and 2 (PKR1 and PKR2). In the present study, we investigated the effects of the prokineticin receptor antagonist PC1 on arthritic pain and the inflammatory response in type II collagen-induced arthritis (CIA) in mice. We demonstrated that PC1, administered subcutaneously from day 25 to day 35 after CIA, improved clinical signs of arthritis such as paw edema, pain, and impaired locomotor activity. In CIA mice, PC1 was also able to lower plasma malondialdehyde (MDA) levels, suggesting a role in reducing oxidative damage, as well as joint expression levels of PK2, PKRs, TNFα, IL-1β, CD4, CD8, and NF-kB. These results suggest that blocking PKRs may be a successful strategy to control arthritic pain and pathology development. KEY MESSAGES: PK2/PKRs expression levels strongly increase in the synovium of RA mice. PC1 treatment shows anti-arthritic activity and reduces arthritis-induced pain. PC1 treatment significantly lowers synovial PK2/PKRs levels. PC1 treatment lowers plasma MDA levels and synovial levels of TNFα and IL -1β PC1 treatment is a viable therapeutic option for RA.

The mechanism of action of paeoniae radix rubra–angelicae sinensis radix drug pair in the treatment of rheumatoid arthritis through PI3K/AKT/NF-κB signaling pathway

Objective: To investigate the effects and mechanisms of Paeoniae radix rubra–Angelicae sinensis radix (P-A) drug pair in the treatment of rheumatoid arthritis (RA).

Methods: Mass spectrometry was employed to accurately characterize the main components of the P-A drug pair. Network pharmacology was used to analyze the main components and pathways of the P-A drug pair in the treatment of RA, and Discovery Studio software was used to molecularly dock the key proteins on the pathway with their corresponding compounds. The levels of serum TNF-a, IL-1β, and IL-6 were measured by enzyme linked immunosorbent assay (ELISA). The histopathology of the ankle joint was observed by hematoxylin-eosin (HE) staining, and the positive expression of p-PI3K, p-IKK, p-NF-κB, and p-AKT in the synovial tissue of the ankle joint was detected by immunohistochemical analysis. Finally, the expression of PI3K, IKK, and AKT and their phosphorylation levels were determined by western blot in each group of rats.

Results: Network pharmacology combined with molecular docking analysis revealed that the pharmacodynamic mechanism of the P-A drug pair for the treatment of RA may be related to the contents of caffeic acid, quercetin, paeoniflorin, and baicalein in the regulation of the expression of the PI3K/AKT/NF-κB signaling pathway and the targets of PIK3CA, PIK3R1, AKT1, HSP90AA1 and IKBKB in the pathway. Compared with the model group, the P-A drug pair significantly improved the pathological changes of the synovial tissue and reduced feet swelling in RA model rats. Moreover, it regulated the levels of TNF-α, IL-1β, and IL-6 in serum (p &lt; 0.05). The results of the immunohistochemical analysis and western blot showed that the expression of PI3K, IKK, NF-κB, and AKT decreased after phosphorylation in the synovial tissue (p &lt; 0.05).

Conclusion: The P-A drug pair exhibited an inhibitory effect on the hyperactivation of the PI3K/AKT/NF-κB signaling pathway in the synovial membrane of RA rats. The mechanism may be related to the downregulation of the phosphorylation levels PI3K, IKK, NF-κB, and AKT, which in turn decreased inflammatory cell infiltration and synovial membrane proliferation.

2-Styrylchromones Prevent IL-1β-Induced Pro-Inflammatory Activation of Fibroblast-like Synoviocytes while Increasing COX-2 Expression

Rheumatoid arthritis (RA) is characterized by systemic immune and chronic inflammatory features, leading to the destruction of the joints. Presently, there are no effective drugs able to control synovitis and catabolism in the process of RA. 2-Styrylchromones (2-SC) are a small group of compounds characterized by the attachment of a styryl group to the chromone core that have already been associated to a wide range of biological activities, including antioxidant and anti-inflammatory activities. The present study investigated the effect of a set of six 2-SC on the interleukin-1β (IL-1β)-induced increase of nitric oxide (•NO), inducible form of nitric oxide synthase (iNOS), cyclooxygenase-2 (COX-2), and matrix metalloproteinase-3 (MMP-3) expression levels in human fibroblast-like synoviocytes (HFLS), pointing to the role of nuclear factor kappa-light-chain-enhancer of activated B cells (NF-κB) activation in the process. From a set of six 2-SC, presenting hydroxy and methoxy substituents, the one presenting two methoxy substituents at C-5 and C-7 of A ring and a catechol group on B ring, significantly reduced •NO production and the expression of its inducible synthase (iNOS). It also significantly reduced the catabolic MMP-3 protein expression. This 2-SC inhibited the NF-κB pathway by reversing the IL-1β - induced levels of cytoplasmatic NF-kB inhibitor alpha (IκBα), and decreasing the p65 nuclear levels, suggesting the involvement of these pathways in the observed effects. The same 2-SC significantly increased the COX-2 expression, which may indicate a negative feedback loop mechanism of action. The properties of 2-SC may be of great value in the development of new therapies with improved efficacy and selectivity towards RA, and thus deserve further exploitation and evaluation to disclose the full potential of 2-SC.

BML-111 inhibits osteoclast differentiation by suppressing the MAPK and NF-κB pathways, alleviating deterioration of the knee joints in a CIA rat model

Irreversible destruction of joints is the hallmark of rheumatoid arthritis (RA). Osteoclasts are the only bone-resorbing cells and play an important role in joint rebuilding. BML-111 (5(S),6(R),7-trihydroxyheptanoic acid methyl ester, C₈ H₁₆ O₅ ) is a synthetic lipoxin A4 agonist with antioxidant and anti-inflammatory properties. The present study aimed to investigate the effect of BML-111 on osteoclasts in vivo and in vitro, to investigate its therapeutic effect on joint destruction in RA. Cell Counting Kit-8 assay and flow cytometry were used to exclude cytotoxic effects of BML-111 to bone marrow-derived macrophages (BMMs). Then, osteoclasts were differentiated in vitro from BMMs by used macrophage colony-stimulating factor and receptor activator of nuclear factor-κB ligand, and osteoclasts were observed following tartrate-resistant acid phosphatase staining with or without BML-111 treatment. Meanwhile, absorption pit assay and immunofluorescence staining of the fibrous actin ring were used to observe osteoclast function. Moreover, we examined mitogen-activated protein kinase (MAPK) and nuclear factor-κB (NF-κB) activation. We established collagen-induced arthritis in a rat model and, after treatment with BML-111, joint swelling was measured and the knee joints were processed for histology. We also examined serum and tissue for osteoclastogenesis-related markers. BML-111 inhibited osteoclast formation and differentiation in a time- and concentration-dependent manner, and downregulated the expression levels of MAPK and NF-κB in vitro. Meanwhile, BML-111 effectively alleviated joint structural damage and inhibited osteoclast formation in vivo. BML-111 inhibited osteoclast formation and differentiation in vitro and in vivo, and delayed the progression of joint destruction.

Orthorexia Nervosa Practices in Rheumatoid Arthritis: The DORA Study

Medical nutrition therapy (MNT) is an indisputable component of the multidisciplinary therapeutic approach in rheumatoid arthritis (RA). Previous research has suggested that in chronic disease where nutrition is an important effector of prognosis, healthy dietary choices might take an unhealthy turn, with patients developing disordered eating in the form of orthorexia nervosa (ON). ON is characterized by a pathological preoccupation with "healthy", "pure" eating, associated with restrictive dietary patterns, nutrient deficiencies and worsening disease outcomes. The aim of the present cross-sectional study was to evaluate ON tendencies in a sample of adult patients with RA. A total of 133 patients with RA were recruited, and completed the ORTO-15 questionnaire for the assessment of ON tendencies. Most of the patients were overweight/obese (53.4%). The results revealed ON tendencies in the sample, with the median ORTO-15 score reaching 36 (IQR: 33-39). Greater ON tendencies were associated with the female gender, and lowered ON tendencies with increasing age and body mass index. The present findings highlight the need for health professional awareness regarding the problem of ON in patients with RA and the importance of screening patients.

Mediterranean Diet and Physical Activity Nudges versus Usual Care in Women with Rheumatoid Arthritis: Results from the MADEIRA Randomized Controlled Trial

In rheumatoid arthritis (RA), diet quality and nutritional status have been shown to impact the disease activity and adherence to the Mediterranean diet (MD) has been suggested as an anti-inflammatory regime to improve disease status and reduce cardiovascular risk. The Mediterranean DiEt In Rheumatoid Arthritis (MADEIRA) was a single-blind (statistician), two-arm randomized clinical trial, investigating the effects of a 12-week lifestyle intervention, including a personalized isocaloric MD plan with the promotion of physical activity (PA), supported through a clinical decision support systems (CDSS) platform, versus usual care in women with RA. Forty adult women with RA on remission were randomly allocated (1:1 ratio) to either the intervention or the control arm. The intervention group received personalized MD plans and lifestyle consultation on improving PA levels, whereas the controls were given generic dietary and PA advice, based on the National Dietary Guidelines. The primary outcome was that the difference in the MD adherence and secondary outcomes included change in disease activity (DAS28), anthropometric indices (BodPod), dietary intake, PA, vitamin D concentrations, and blood lipid profiles after 12 weeks from the initiation of the trial. At 3 months post-baseline, participants in the MD arm exhibited greater adherence to the MD compared with the controls (p < 0.001), lower DAS28 (p < 0.001), favorable improvements in dietary intake (p = 0.001), PA (p = 0.002), body weight and body composition (p < 0.001), blood glucose (p = 0.005), and serum 1,25(OH)₂D concentrations (p < 0.001). The delivery of the MD and PA promotion through CDSS nudges in women with RA in an intensive manner improves the MD adherence and is associated with beneficial results regarding disease activity and cardiometabolic-related outcomes, compared with the usual care.

Screening and identification of potential hub genes and immune cell infiltration in the synovial tissue of rheumatoid arthritis by bioinformatic approach

Background

Rheumatoid arthritis (RA) is an autoimmune disease that affects individuals of all ages. The basic pathological manifestations are synovial inflammation, pannus formation, and erosion of articular cartilage, bone destruction will eventually lead to joint deformities and loss of function. However, the specific molecular mechanisms of synovitis tissue in RA are still unclear. Therefore, this study aimed to screen and explore the potential hub genes and immune cell infiltration in RA.

Methods

Three microarray datasets (GSE12021, GSE55457, and GSE55235), from the Gene Expression Omnibus (GEO) database, have been analyzed to explore the potential hub genes and immune cell infiltration in RA. First, the LIMMA package was used to screen the differentially expression genes (DEGs) after removing the batch effect. Then the clusterProfiler package was used to perform functional enrichment analyses. Second, through weighted coexpression network analysis (WGCNA), the key module was identified in the coexpression network of the gene set. Third, the protein-protein interaction (PPI) network was constructed through STRING website and the module analysis was performed using Cytoscape software. Fourth, the CIBERSORT and ssGSEA algorithm were used to analyze the immune status of RA and healthy synovial tissue, and the associations between immune cell infiltration and RA-related diagnostic biomarkers were evaluated. Fifth, we used the quantitative reverse transcription-polymerase chain reaction (qRT-PCR) to validate the expression levels of the hub genes, and ROC curve analysis of hub genes for discriminating between RA and healthy tissue. Finally, the gene-drug interaction network was constructed using DrugCentral database, and identification of drug molecules based on hub genes using the Drug Signature Database (DSigDB) by Enrichr.

Results

A total of 679 DEGs were identified, containing 270 downregulated genes and 409 upregulated genes. DEGs were primarily enriched in immune response and chemokine signaling pathways, according to functional enrichment analysis of DEGs. WGCNA explored the co-expression network of the gene set and identified key modules, the blue module was selected as the key module associated with RA. Seven hub genes are identified when PPI network and WGCNA core modules are intersected. Immune infiltration analysis using CIBERSORT and ssGSEA algorithms revealed that multiple types of immune infiltration were found to be upregulated in RA tissue compared to normal tissue. Furthermore, the levels of 7 hub genes were closely related to the relative proportions of multiple immune cells in RA. The results of the qRT-PCR demonstrated that the relative expression levels of 6 hub genes (CD27, LCK, CD2, GZMB, IL7R, and IL2RG) were up-regulated in RA synovial tissue, compared with normal tissue. Simultaneously, ROC curves indicated that the above 6 hub genes had strong biomarker potential for RA (AUC >0.8).

Conclusions

Through bioinformatics analysis and qRT-PCR experiment, our study ultimately discovered 6 hub genes (CD27, LCK, CD2, GZMB, IL7R, and IL2RG) that closely related to RA. These findings may provide valuable direction for future RA clinical diagnosis, treatment, and associated research.

Phosphatidyl Inositol 3-Kinase (PI3K)-Inhibitor CDZ173 protects against LPS-induced osteolysis

A major complication of a joint replacement is prosthesis loosening caused by inflammatory osteolysis, leading to the revision of the operation. This is due to the abnormal activation of osteoclast differentiation and function caused by periprosthetic infection. Therefore, targeting abnormally activated osteoclasts is still effective for treating osteolytic inflammatory diseases. CDZ173 is a selective PI3K inhibitor widely used in autoimmune-related diseases and inflammatory diseases and is currently under clinical development. However, the role and mechanism of CDZ173 in osteoclast-related bone metabolism remain unclear. The possibility for treating aseptic prosthesis loosening brought on by inflammatory osteolysis illness can be assessed using an LPS-induced mouse cranial calcium osteolysis model. In this study, we report for the first time that CDZ173 has a protective effect on LPS-induced osteolysis. The data show that this protective effect is due to CDZ173 inhibiting the activation of osteoclasts in vivo. Meanwhile, our result demonstrated that CDZ173 had a significant inhibitory effect on RANKL-induced osteoclasts. Furthermore, using the hydroxyapatite resorption pit assay and podosol actin belt staining, respectively, the inhibitory impact of CDZ173 on bone resorption and osteoclast fusion of pre-OC was determined. In addition, staining with alkaline phosphatase (ALP) and alizarin red (AR) revealed that CDZ173 had no effect on osteoblast development in vitro. Lastly, CDZ173 inhibited the differentiation and function of osteoclasts by weakening the signal axis of PI3K-AKT/MAPK-NFATc1 in osteoclasts. In conclusion, our results highlight the potential pharmacological role of CDZ173 in preventing osteoclast-mediated inflammatory osteolysis and its potential clinical application.

Pulsed Electromagnetic Field (PEMF) Treatment Ameliorates Murine Model of Collagen-Induced Arthritis

Rheumatoid arthritis (RA) is an autoimmune disease of the joint synovial membranes. RA is difficult to prevent or treat; however, blocking proinflammatory cytokines is a general therapeutic strategy. Pulsed electromagnetic field (PEMF) is reported to alleviate RA's inflammatory response and is being studied as a non-invasive physical therapy. In this current study, PEMF decreased paw inflammation in a collagen-induced arthritis (CIA) murine model. PEMF treatment at 10 Hz was more effective in ameliorating arthritis than at 75 Hz. In the PEMF-treated CIA group, the gross inflammation score and cartilage destruction were lower than in the untreated CIA group. The CIA group treated with PEMF also showed lower serum levels of IL-1β but not IL-6, IL-17, or TNF-α. Serum levels of total anti-type II collagen IgG and IgG subclasses (IgG1, IgG2a, and IgG2b) remained unchanged. In contrast, tissue protein levels of IL-1β, IL-6, TNF-α, receptor activator of nuclear factor kappa-Β (RANK), RANK ligand (RANKL), IL-6 receptor (IL-6R), and TNF-α receptor1 (TNFR1) were all lower in the ankle joints of the PEMF-treated CIA group compared with the CIA group. The results of this study suggest that PEMF treatment can preserve joint morphology cartilage and delay the occurrence of CIA. PEMF has potential as an effective adjuvant therapy that can suppress the progression of RA.

Nesfatin-1 Stimulates CCL2-dependent Monocyte Migration And M1 Macrophage Polarization: Implications For Rheumatoid Arthritis Therapy

Rheumatoid arthritis (RA) is a prototypic inflammatory disease, characterized by the infiltration of proinflammatory cytokines into the joint synovium and the migration of mononuclear cells into inflammatory sites. The adipokine nesfatin-1 is linked to inflammatory events in various diseases, although its role in RA pathology is uncertain. Analysis of the Gene Expression Omnibus GSE55235 dataset revealed high levels of expression of the adipokine nesfatin-1 in human RA synovial tissue. Similarly, our human synovial tissue samples exhibited increasing levels of nesfatin-1 expression and Ccl2 mRNA expression. Nesfatin-1-induced stimulation of CCL2 expression and monocyte migration involved the MEK/ERK, p38, and NF-κB signaling pathways. Notably, nesfatin-1-induced increases in CCL2 expression favored M1 macrophage polarization, which increased the expression of proinflammatory cytokines IL-1β, IL-6, and TNF-α. Finally, nesfatin-1 shRNA ameliorated the severity of inflammatory disease and reduced levels of M1 macrophage expression in CIA mice. Our studies confirm that nesfatin-1 appears to be worth targeting in RA treatment.

Systemic complications of rheumatoid arthritis: Focus on pathogenesis and treatment

As a systemic autoimmune disease, rheumatoid arthritis (RA) usually causes damage not only to joints, but also to other tissues and organs including the heart, kidneys, lungs, digestive system, eyes, skin, and nervous system. Excessive complications are closely related to the prognosis of RA patients and even lead to increased mortality. This article summarizes the serious complications of RA, focusing on its incidence, pathogenesis, clinical features, and treatment methods, aiming to provide a reference for clinicians to better manage the complications of RA.

Chemically modified small interfering RNA targeting Hedgehog signaling pathway for rheumatoid arthritis therapy

Rheumatoid arthritis (RA) is an inflammatory disease that leads to disability; however, existing therapies are still unsatisfactory. Activated fibroblast-like synoviocytes (FLSs) play an essential role in synovitis formation and joint destruction in RA. The Hedgehog signaling pathway is aberrantly activated and contributes to the aggressive phenotype of RA-FLSs. However, it remains uncertain whether inhibiting Smoothened (SMO), a critical component of the Hedgehog signaling pathway, is an effective treatment for RA. Here, we design a series of small interfering RNAs (siRNAs) that specifically target the SMO gene. With precise chemical modifications, siRNAs' efficacy and stability are significantly improved, and the off-target effects are minimized. The optimized chemically modified siRNA (si-S1A3-Chol) decreases RA-FLS proliferation and invasiveness without the transfection reagent. Furthermore, si-S1A3-Chol injected intra-articularly effectively alleviates joint destruction and improves motor function in collagen-induced arthritis mouse models. Consequently, our results demonstrate that chemically modified siRNA targeting the Hedgehog signaling pathway may be a potential therapy for RA.

Emerging insights of peptide-based nanotherapeutics for effective management of rheumatoid arthritis

Rheumatoid arthritis (RA) is a chronic, prevalent, immune-mediated, inflammatory, joint disorder affecting millions of people worldwide. Despite current treatment options, many patients remain unable to achieve remission and suffer from comorbidities. Because of several comorbidities as well as its chronic nature, it diminishes the quality of patients' life and intensifies socioeconomic cargo. Consolidating peptides with immensely effective drug delivery systems has the ability to alleviate adverse effects associated with conventional treatments. Peptides are widely used as targeting moieties for the delivery of nanotherapeutics. The use of novel peptide-based nanotherapeutics may open up new avenues for improving efficacy by promoting drug accumulation in inflamed joints and reducing off-target cytotoxicity. Peptide therapeutics have grabbed significant attention due to their advantages over small drug molecules as well as complex targeting moieties. In light of this, the market for peptide-based medications is growing exponentially. Peptides can provide the versatility required for the successful delivery of drugs due to their structural diversity and their capability to lead drugs at the site of inflammation while maintaining optimum therapeutic efficacy. This comprehensive review aims to provide an enhanced understanding of recent advancements in the arena of peptide-based nanotherapeutics to strengthen targeted delivery for the effective management of rheumatoid arthritis. Additionally, various peptides having therapeutic roles in rheumatoid arthritis are summarized along with regulatory considerations for peptides.

NLRC4-mediated activation of CD1c+ DC contributes to perpetuation of synovitis in rheumatoid arthritis

The individual contribution of specific myeloid subsets such as CD1c+ conventional DC (cDC) to perpetuation of rheumatoid arthritis (RA) pathology remains unclear. In addition, the specific innate sensors driving pathogenic activation of CD1c+ cDC in patients with RA and their functional implications have not been characterized. Here, we assessed phenotypical, transcriptional, and functional characteristics of CD1c+ and CD141+ cDC and monocytes from the blood and synovial fluid of patients with RA. Increased levels of CCR2 and the IgG receptor CD64 on circulating CD1c+ cDC was associated with the presence of this DC subset in the synovial membrane in patients with RA. Moreover, synovial CD1c+ cDC are characterized by increased expression of proinflammatory cytokines and high abilities to induce pathogenic IFN-γ+IL-17+CD4+ T cells in vitro. Finally, we identified the crosstalk between Fcγ receptors and NLRC4 as a potential molecular mechanism mediating pathogenic activation, CD64 upregulation, and functional specialization of CD1c+ cDC in response to dsDNA-IgG in patients with RA.

Epimedii Herba: An ancient Chinese herbal medicine in the prevention and treatment of rheumatoid arthritis

Rheumatoid arthritis (RA) is a chronic, progressive inflammatory and systemic autoimmune disease resulting in severe joint destruction, lifelong suffering and considerable disability. Diverse prescriptions of traditional Chinese medicine (TCM) containing Epimedii Herba (EH) achieve greatly curative effects against RA. The present review aims to systemically summarize the therapeutic effect, pharmacological mechanism, bioavailability and safety assessment of EH to provide a novel insight for subsequent studies. The search terms included were "Epimedii Herba", "yinyanghuo", "arthritis, rheumatoid" and "Rheumatoid Arthritis", and relevant literatures were collected on the database such as Google Scholar, Pubmed, Web of Science and CNKI. In this review, 15 compounds from EH for the treatment of RA were summarized from the aspects of anti-inflammatory, immunoregulatory, cartilage and bone protective, antiangiogenic and antioxidant activities. Although EH has been frequently used to treat RA in clinical practice, studies on mechanisms of these activities are still scarce. Various compounds of EH have the multifunctional traits in the treatment of RA, so EH may be a great complementary medicine option and it is necessary to pay more attention to further research and development.

The inhibitory effect of tocilizumab on systemic bone loss and tendon inflammation in a juvenile Collagen-Induced arthritis rat model

PURPOSE OF THE STUDY

Reduced Bone Mineral Density (BMD) is a prevalent comorbidity in Juvenile Idiopathic Arthritis (JIA). Enthesitis and other tendon abnormalities, such as tenosynovitis, tendinitis and tendon ruptures are, also, common extra-articular manifestations of the disease. The aim of the present study was to investigate the effect of tocilizumab, an antibody that binds the Interleukin-6 (IL-6) Receptor, on inflammation-related bone loss and tendon inflammation in an animal model of JIA.

MATERIALS AND METHODS

The Collagen-Induced Arthritis (CIA) model was induced in male rats followed by intraperitoneal administration of tocilizumab for 8 weeks. Methotrexate, the most widely used Disease-Modifying Antirheumatic Drug in the management of JIA, was, also, administered, either as a monotherapy or as an add-on therapy to tocilizumab. BMD was evaluated with Micro-Computed Tomography (Micro-CT) and histopathological examination. Tendon damage was, also, assessed histologically. Finally, two pro-inflammatory cytokines, Tumor Necrosis Factor-alpha (TNF-a) and Interleukin-23 (IL-23) were quantified in tendon tissues by ELISA analysis.

RESULTS

Tocilizumab-treated animals exhibited a significantly improved trabecular microarchitecture on micro-CT analysis and histological examination. Tendon morphology was also improved. Anti-IL-6 treatment led to a significant decrease in TNF-a and IL-23 expression in tendon tissue.

CONCLUSIONS

The results of the present study provide evidence that tocilizumab reduces inflammation-related bone loss and suppresses tendon inflammation in a juvenile CIA rat model. These findings offer perspectives for the management of osteoporosis and enthesitis in JIA.

The bone-protective mechanisms of active components from TCM drugs in rheumatoid arthritis treatment

Rheumatoid arthritis (RA) is an autoimmune disease whose hallmarks are synovial inflammation and irreversible bone destruction. Bone resorption resulting from osteoclasts involves the whole immune and bone systems. Breakdown of bone remodeling is attributed to overactive immune cells that produce large quantities of cytokines, upregulated differentiation of osteoclasts with enhanced resorptive activities, suppressed differentiation of osteoblasts, invading fibroblasts and microbiota dysbiosis. Despite the mitigation of inflammation, the existing treatment in Western medicine fails to prevent bone loss during disease progression. Traditional Chinese medicine (TCM) has been used for thousands of years in RA treatment, showing great efficacy in bone preservation. The complex components from the decoctions and prescriptions exhibit various pharmacological activities. This review summarizes the research progress that has been made in terms of the bone-protective effect of some representative compounds from TCM drugs and proposes the substantial mechanisms involved in bone metabolism to provide some clues for future studies. These active components systemically suppress bone destruction via inhibiting joint inflammation, osteoclast differentiation, and fibroblast proliferation. Neutrophil, gut microenvironment and microRNA has been proposed as future focus.

Synovial Macrophages Expression of OX40L Is Required for Follicular Helper T Cells Differentiation in the Joint Microenvironment

Signaling via the OX40/OX40L axis plays a key role in CD4⁺ T cell development, and OX40L expression is primarily restricted to antigen-presenting cells (APCs). This study was designed to assess the role of APC-mediated OX40L expression in the context of the development of rheumatoid arthritis (RA)-associated CD4⁺ T cell subsets. For these analyses, clinical samples were harvested from patients with osteoarthritis and RA, with additional analyses performed using OX40^−/− mice and mice harboring monocyte/macrophage-specific deletions of OX40L. Together, these analyses revealed tissue-specific roles for OX40/OX40L signaling in RA. Specifically, higher levels of synovial macrophage OX40L expression were associated with the enhanced development of T follicular helper cells in the joint microenvironment, thereby contributing to the pathogenesis of RA. This Tfh differentiation was found to be OX40/OX40L-dependent in this synovial setting. Overall, these results indicate that the expression of OX40L by synovia macrophages is necessary to support Tfh differentiation in the joint tissues, thus offering new insight regarding the etiological basis for RA progression.