Lessons From the Success and Failure of Targeted Drugs for Rheumatoid Arthritis: Perspectives for Effective Basic and Translational Research

Developing an in vitro osteochondral micro-physiological system for modeling cartilage-bone crosstalk in arthritis

Introduction

Arthritis, a disease affecting over 50 million adults in the United States, encompasses many different conditions involving joints and surrounding tissues. Disease development, progression, and subsequent treatment is dependent on many different factors, including the relationship between adjacent tissues and the immunological signals involved. A major contributor to disease regulation is the crosstalk between the cartilage and the bone in joints, as well as their reaction to immune factors such as cytokine signaling and macrophage mediation. Studying cartilage-bone crosstalk in arthritis development can be difficult, as controlling immunological factors in vivo is challenging, but in vitro models often lack multi-tissue relevancy.

Methods

To fix this, we developed an in vitro micro-physiological system using a biphasic bioreactor that supports modeling of multiple tissues. We generated cartilage and vascularized-bone analogs and combined them in the bioreactor to allow diffusion and signaling between them. Using this system, we directly induced inflammation in the cartilage region and studied how crosstalk between the two adjacent tissues contributed to disease progression.

Results

We showed that conditioned media from pro-inflammatory macrophages generated a different inflammatory profile than a simple inflammatory cytokine cocktail. We also showed that the vascularized-bone region became inflamed in response to the cartilage inflammation, verifying crosstalk in the system and successfully modeling the relationship between cartilage and bone in an arthritic environment.

Discussion

This model can be used to further probe the crosstalk between bone and cartilage in arthritis, allowing researchers to tease out the effect of specific inflammatory agents or therapeutics in vitro.

Development of ROS-Sensitive Sulfasalazine-Loaded Ferrocene Nanoparticles and Evaluation of Their Antirheumatic Effects in a 3D Synovial Hyperplasia Model

Rheumatoid arthritis (RA) is a chronic inflammatory autoimmune disease characterized by joint inflammation, synovial hyperplasia, and bone and cartilage destruction, which significantly impairs physical function and quality of life. Disease-modifying antirheumatic drugs, such as sulfasalazine (SSZ), are crucial for altering the course and progression of RA; however, their clinical use is hampered by poor water solubility and lack of specificity for the reactive oxygen species (ROS)-rich environment typical of RA. To overcome these challenges, ROS-sensitive SSZ-loaded ferrocene nanoparticles are developed. The nanoparticles facilitate enhanced solubility and stability of SSZ and particularly enable precision targeting through the distinctive redox properties of ferrocene. Using a 3D synovial hyperplasia model with fibroblast-like synoviocytes derive from RA patients and validate at both the protein and gene levels, these nanoparticles significantly reduce lactate dehydrogenase, ROS, and inflammatory cytokine levels. Further validation using a collagen-induced arthritis model demonstrates therapeutic efficacy and cytokine modulation in vivo. These findings highlight the potential of ferrocene nanoparticles as a novel and effective therapeutic strategy for RA, offering improved drug delivery and reduced systemic toxicity.

Blood molecular subtypes to guide precision treatment strategies in systemic juvenile idiopathic arthritis

BACKGROUND

Systemic juvenile idiopathic arthritis (sJIA) is the most severe subtype of JIA, with a combination of diverse clinical manifestations and a variable clinical course. A comprehensive understanding of molecular signatures at the systems level and the discovery of molecular subtypes are the initial steps toward personalized medicine in sJIA.

METHODS

A blood transcriptomic dataset was collected from patients with systemic JIA (sJIA) (n = 168), polyarticular JIA (n = 254), oligoarticular JIA (n = 96), enthesitis-related arthritis (n = 40), and healthy controls (n = 220). Gene expression profiles were filtered for differentially expressed genes and unsupervised clustering, gene set enrichment, and network-based centrality analyses. The molecular signatures of three novel sJIA subgroups (designated as C1, C2, and C3) were investigated, focusing on their distinct features and treatment responses.

RESULTS

Neutrophil degranulation and the IL-1 signaling pathway were the shared key processes for the three subgroups. Proinflammatory signals, including TNF, IL-6, TLR, and G-CSF signaling pathways, were identified with variation across the subgroups. C1 was the most inflammatory subset with a high-risk profile for macrophage activation syndrome. The C2 subset had the most activated IL-1 and IL-18 signaling pathways. C2 and C3 have higher levels of interferon-stimulated signatures. In a canakinumab-treated dataset, treatment response was correlated with IL1B expression and NF-κB signaling pathway, and neutrophil activation-associated processes were effectively suppressed in a good responder group. GSK3B and p38 MAPK inhibitors showed a significant counteracting effect on the perturbed gene expression of sJIA.

CONCLUSIONS

Neutrophil activation was the key feature in active sJIA. The three molecular subtype scheme enables the formulation of precision medicine strategies in sJIA.

The HRAS-binding C2 domain of PLCη2 suppresses tumor-like synoviocytes and experimental arthritis in rheumatoid arthritis

Fibroblast-like synoviocytes (FLSs), which are stromal cells that play key roles in rheumatoid arthritis (RA) pathophysiology, are characterized by a tumor-like phenotype and immunostimulatory actions. C2 domains in various proteins play roles in intracellular signaling and altering cellular characteristics, and some C2 domain-containing proteins exacerbate or alleviate certain malignant or inflammatory diseases. However, the roles of C2 domains in regulating the functions of RA FLSs remain unclear. Here we performed functional C2 domainomics with 144 C2 domain-containing viral vectors and identified the C2 domain of PLCη2 as a key regulator of RA FLSs. In mice, overexpressing PLCη2 or only its C2 domain PLCη2 (PLCη2_C2) diminished the proliferation, migration, invasion and inflammatory responses of RA FLSs, mitigating RA pathology; the absence of PLCη2 amplified these proinflammatory and destructive processes in RA FLSs in vivo. Mechanistically, PLCη2 and PLCη2_C2 participate in the pathological signaling of RA FLSs in a calcium-independent manner through protein-protein interactions. Specifically, PLCη2_C2 disrupted HRAS-RAF1 interactions, suppressing downstream signaling pathways, including the NF-κB, JAK-STAT and MAPK pathways. Collectively, these findings establish PLCη2 and PLCη2_C2 as novel inhibitory regulators in RA, suggesting promising therapeutic avenues for addressing FLS-driven disease mechanisms.

Suberosin attenuates rheumatoid arthritis by repolarizing macrophages and inhibiting synovitis via the JAK/STAT signaling pathway

BACKGROUND

Rheumatoid arthritis (RA) is a systemic disease that primarily manifests as chronic synovitis of the symmetric small joints. Despite the availability of various targeted drugs for RA, these treatments are limited by adverse reactions, warranting new treatment approaches. Suberosin (SBR), isolated from Plumbago zeylanica-a medicinal plant traditionally used to treat RA in Asia-possesses notable biological activities. This study aimed to investigate the effects and potential underlying pathways of SBR on RA.

METHODS

Tumor necrosis factor-alpha (TNF-α) induced inflammation in RA-derived fibroblast-like synoviocytes (RA-FLS), and the expression of proinflammatory mediators was assessed using q-RT PCR and ELISA after treatment with various SBR concentrations. Bone marrow-derived macrophages (BMDMs) were induced to differentiate into M1 and M2 macrophages, followed by treatment with various SBR concentrations and macrophage polarization assessment. Low-dose (0.5 mg/kg/d) and high-dose (2 mg/kg/d) SBR regimens were administered to a collagen-induced arthritis (CIA) mouse model for 21 days, and the anti-arthritic effects of SBR were evaluated. Network pharmacology and molecular docking analyses were used to predict the anti-arthritic targets of SBR. The effect of SBR on the Janus kinase/signal transducer and activator of transcription (JAK/STAT) pathway was evaluated.

RESULTS

SBR suppressed macrophage polarization toward the M1 phenotype while enhancing their polarization toward the M2 phenotype. SBR reduced the levels of proinflammatory mediators in TNF-α-induced RA-FLS. Mechanistically, SBR inhibited the phosphorylation of the JAK1/STAT3 signaling pathway in RA-FLS and M1 macrophages and promoted the phosphorylation of the JAK1/STAT6 pathway in M2 macrophages, enhancing M2 polarization. In vivo, prophylactic treatment of low-dose SBR reduced M1 macrophage infiltration into synovial tissue, increased the proportion of M2 macrophages, and decreased the expression of inflammatory mediators in the serum and synovial tissue, alleviating synovial inflammation. SBR significantly alleviated arthritis in CIA mice through macrophage repolarization and inhibition of inflammation.

CONCLUSION

SBR significantly reduced clinical symptoms, joint pathological damage, and expression inflammatory cytokine expression in CIA mice. SBR exhibited anti-arthritic effects via the JAK1/STAT3 and JAK1/STAT6 signaling pathways, inhibiting synovial tissue inflammation and M1 macrophage polarization while promoting M2 macrophage polarization. Therefore, SBR may be an effective candidate for RA treatment.

Sea Hare Hydrolysate Reduces PD-L1 Levels in Cancer Cells and Mitigates Rheumatoid Arthritis Ina Collagen-Induced Arthritis Mouse Model

Our previous study highlighted the anticancer potential of sea hare hydrolysate (SHH), particularly its role in regulating macrophage polarization and inducing pyroptotic death in lung cancer cells through the inhibition of signal transducer and activator of transcription 3 (STAT3). These findings prompted us to investigate additional features of immune-oncology (I-O) agents or adjuvants, such as programmed cell death protein 1 (PD-1)/programmed death ligand 1 (PD-L1) inhibition and their association with rheumatoid arthritis (RA) risk, to explore the potential of SHH as an I-O agent or adjuvant. In this study, we investigated the effects of SHH on PD-L1 levels in various cancer cell types and assessed its effectiveness in treating RA, a common side effect of I-O agents. Our results showed a marked reduction in PD-L1 levels in multiple cancer cell lines and decreased PD-1 and PD-L1 levels in tumor-associated macrophages. In a mouse model with collagen-induced arthritis (CIA), SHH exhibited anti-inflammatory effects comparable to methotrexate (MTX), a first-line treatment for RA. Both the SHH and MTX groups had significantly lower arthritis scores and paw thickness compared to the CIA group. Additionally, SHH or MTX treatment effectively reduced elevated levels of anticollagen type II (CII) antibodies and proinflammatory cytokines (IL-1β, IL-6, and TNF-α). Histopathological analysis revealed that SHH and MTX treatments notably mitigated arthritic inflammation, synovial hyperplasia, and loss of articular cartilage and bone. Micro-CT scans showed reduced articular destruction in the SHH and MTX groups. These findings indicate that SHH treatment decreases PD-L1 levels in cancer cells and reduces the severity of CIA by exerting anti-inflammatory effects. Therefore, SHH holds promise as an I-O agent without side effects such as exacerbation of RA.

Propionibacterium freudenreichii MJ2-derived extracellular vesicles inhibit RANKL-induced osteoclastogenesis and improve collagen-induced rheumatoid arthritis

Rheumatoid arthritis causes excessive bone loss by stimulating osteoclast differentiation. Extracellular vesicles are valuable disease markers, conveyors of distant cell-to-cell communication, and carriers for drug delivery. The aim of this study was to investigate the anti-osteoclastogenic effects of extracellular vesicles derived from dairy Propionibacterium freudenreichii MJ2 (PFEVs) and the improvement effect of PFEVs on collagen-induced arthritis (CIA) animal model. PFEVs were observed by scanning electron microscopy, transmission electron microscopy, nanoparticle tracking analysis, and LC-MS/MS. The inhibitory activity of PFEVs against receptor activator of nuclear factor kappa-B ligand (RANKL)-induced osteoclast differentiation was investigated in RAW 264.7 cells. PFEVs significantly decreased the expression levels of genes and proteins related to osteoclast differentiation. PFEVs decreased RANK-RANKL binding. In a CIA mouse model, PFEVs treatment significantly reduced arthritis scores and collagen-specific immunoglobulins. PFEVs treatment also reduced pro-inflammatory cytokines and increased anti-inflammatory cytokines. The anti-inflammatory effects were confirmed by H&E staining, and PFEVs treatment inhibited osteoclastogenesis in the CIA mouse model. In conclusion, PFEVs inhibited osteoclast differentiation by inhibiting RANK-RANKL signaling, thereby decreasing the expression of osteoclast differentiation-related genes. PFEVs also improved collagen-induced arthritis by inhibiting inflammation and osteoclastogenesis.

Unlocking the Future: New Biologic Therapies for Rheumatoid Arthritis

Rheumatoid arthritis (RA) is a chronic autoimmune disorder that leads to joint destruction and functional disability. Traditional treatments, including disease-modifying antirheumatic drugs (DMARDs), often fail, leaving many patients without remission. The advent of biologic therapies that target specific immune system components (e.g., cytokines, T cells) has transformed RA treatment by offering new management options. These biologics (e.g., TNF inhibitors, interleukin blockers) are highly effective in controlling disease activity and preventing joint destruction. However, their use comes with safety concerns, particularly regarding immunosuppression and infection risks. Although still experimental, studies predict that future research will focus on enhancing the clinical response and safety of these agents through personalized approaches or novel mechanisms of action.

Role of Interleukin-17 in Predicting Activity of Rheumatoid Arthritis and Systemic Lupus Erythematosus

Background

Although high serum levels of interleukin (IL)-17 and its producing cells have been found in rheumatoid arthritis (RA) and systemic lupus erythematosus (SLE) in earlier research, it is still unclear how these findings relate to disease activity.

Objectives

This study examines the link between serum levels of IL-17 and the activity of both RA and SLE.

Design

This pilot case-control study included 100 patients with RA, 100 with SLE, and 100 healthy controls.

Methods

The Disease Activity Score-28 (DAS28) scores assessed the activity of RA, whereas the Systemic Lupus Erythematosus Disease Activity Index 2000 (SLEDAI-2K) scores assessed SLE activity. All participants' data were compared and correlated.

Results

Serum levels of IL-17 were significantly higher in RA and SLE patients compared with the controls (P < .001) and showed significantly positive correlations (P < .001) with rheumatoid factor titer, anti-cyclic citrullinated peptide (anti-CCP) and DAS28 score among the RA patients. Although among SLE patients, they were significantly positively correlated (P < .001) with anti-double-stranded DNA (anti-ds DNA) levels and the SLEDAI-2K scores, the best cut-off value of IL-17 for predicting moderate and high disease activity was > 175 pg/mL among RA patients and > 95 pg/mL among SLE patients.

Conclusions

There is a significant correlation between RA and SLE activity and serum levels of IL-17. This discovery emphasizes IL-17 as a potential therapeutic target.

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.

Different modalities to manage rheumatoid arthritis: an A to Z story

Aim: To investigate different approaches to RA treatment that might lead to greater efficacy and better safety profiles. Methods: The Search strategy was based on medical subject headings, and screening and selection were based on inclusion/exclusion criteria. Results & discussion: Early therapy is critical for disease control and loss of bodily function. The most promising outcomes came from the development of disease-modifying anti-rheumatic drugs. Different foods have anti-inflammatory and antioxidant qualities that protect against the development of rheumatoid arthritis (RA). Some dietary patterns and supplements have been shown to have potential protective benefits against RA. Conclusion: Improvement in the quality of life of RA patients requires a tailored management approach based on the current patient medical data.

The Biologic IRL201805 Alters Immune Tolerance Leading to Prolonged Pharmacodynamics and Efficacy in Rheumatoid Arthritis Patients

A homologue of binding immunoglobulin protein/BiP-IRL201805 alters the function of immune cells in pre-clinical in vivo and in vitro studies. The aim of the study was to select biomarkers that clearly delineate between RA patients who respond to IRL201805 and placebo patients and reveal the immunological mode of action of IRL201805 driving the extended pharmacodynamics observed in responding patients. Biomarkers that distinguished between responding patients and placebo patients included downregulation of serum interferon-γ and IL-1β; upregulation of anti-inflammatory mediators, serum soluble CTLA-4, and intracellular monocyte expression of IDO; and sustained increased CD39 expression on CD3+CD4+CD25hi CD127lo regulatory T cells. In the responding patients, selected biomarkers verified that the therapeutic effect could be continuous for at least 12 weeks post-infusion. In secondary co-culture, pre-infusion PBMCs cultured 1:1 with autologous PBMCs, isolated at later time-points during the trial, showed significantly inhibited IL-6 and IL-1β production upon anti-CD3/CD28 stimulation demonstrating IRL201805 alters the function of immune cells leading to prolonged pharmacodynamics confirmed by biomarker differences. IRL201805 may be the first of a new class of biologic drug providing long-term drug-free therapy in RA.

Naturopathic Interventions for Reduction of Perceived Pain in Patients Suffering from Arthritis: A Systematic Review and Meta-Analysis

Arthritis affects millions of lives with its pervasive effects on physical health and quality of life. Addressing the complexities of managing symptoms such as swelling, inflammation, and pain requires prolonged treatment. Naturopathy is a treatment method that enhances the body's innate ability to restore optimal health through a holistic approach including natural products and lifestyle modifications. This systematic review addresses the intersection of naturopathy and arthritis treatment to provide current evidence about its potential benefits. Four databases (PubMed, AYUSH Research Portal, Web of Science, and Google Scholar) were searched with the keywords "Naturopathy" AND "Arthritis". Randomized, non-randomized, and cross-over studies in English were included. Studies reporting perceived pain using a visual analogue scale (VAS) were selected for meta-analysis. A total of 15 studies were included in the systematic review. The studies were from Denmark, Egypt, France, Hungary, Israel, Italy, Spain, and Turkey, and the study periods ranged from 1992 to 2017. They suggested that naturopathic treatment modalities like exercise, mud compress, sand bath, or hydrotherapy may be used in addition to conventional modes of treatment for added benefit. There was a diversity of naturopathic treatment modalities and outcome evaluation methods. Most studies used mud compress or mud baths with reported improvement of symptoms. The meta-analysis of 10 studies (11 sets of data) showed a significant improvement in pain measured by VAS. The studies included in the review have a high level of heterogenicity. There is a need for more studies and uniform assessment methods with standardization of interventions for robust evidence. More clinical trials from countries where naturopathy is approved treatment modalities are needed.

Interleukin-18 Binding Protein (IL-18BP): A Long Journey From Discovery to Clinical Application

IL-18 binding protein (IL-18BP) was originally discovered in 1999 while attempting to identify an IL-18 receptor ligand binding chain (also known as IL-18Rα) by subjecting concentrated human urine to an IL-18 ligand affinity column. The IL-18 ligand chromatography purified molecule was analyzed by protein microsequencing. The result revealed a novel 40 amino acid polypeptide. To isolate the complete open reading frame (ORF), various human and mouse cDNA libraries were screened using cDNA probe derived from the novel IL-18 affinity column bound molecule. The identified entire ORF gene was thought to be an IL-18Rα gene. However, IL-18BP has been proven to be a unique soluble antagonist that shares homology with a variety of viral proteins that are distinct from the IL-18Rα and IL-18Rβ chains. The IL-18BP cDNA was used to generate recombinant IL-18BP (rIL-18BP), which was indispensable for characterizing the role of IL-18BP in vitro and in vivo. Mammalian cell lines were used to produce rIL-18BP due to its glycosylation-dependent activity of IL-18BP (approximately 20 kDa). Various forms of rIL-18BP, intact, C-terminal his-tag, and Fc fusion proteins were produced for in vitro and in vivo experiments. Data showed potent neutralization of IL-18 activity, which seems promising for clinical application in immune diseases involving IL-18. However, it was a long journey from discovery to clinical use although there have been various clinical trials since IL-18BP was discovered in 1999. This review primarily covers the discovery of IL-18BP along with how basic research influences the clinical development of IL-18BP.

Cytokines, Vascular Endothelial Growth Factors, and PlGF in Autoimmunity: Insights From Rheumatoid Arthritis to Multiple Sclerosis

In this review, we will explore the intricate roles of cytokines and vascular endothelial growth factors in autoimmune diseases (ADs), with a particular focus on rheumatoid arthritis (RA) and multiple sclerosis (MS). AD is characterized by self-destructive immune responses due to auto-reactive T lymphocytes and Abs. Among various types of ADs, RA and MS possess inflammation as a central role but in different sites of the patients. Other common aspects among these two ADs are their chronicity and relapsing-remitting symptoms requiring continuous management. First factor inducing these ADs are cytokines, such as IL-6, TNF-α, and IL-17, which play significant roles in the pathogenesis by contributing to inflammation, immune cell activation, and tissue damage. Secondly, vascular endothelial growth factors, including VEGF and angiopoietins, are crucial in promoting angiogenesis and inflammation in these two ADs. Finally, placental growth factor (PlGF), an emerging factor with bi-directional roles in angiogenesis and T cell differentiation, as we introduce as an "angio-lymphokine" is another key factor in ADs. Thus, while angiogenesis recruits more inflammatory cells into the peripheral sites, cytokines secreted by effector cells play critical roles in the pathogenesis of ADs. Various therapeutic interventions targeting these soluble molecules have shown promise in managing autoimmune pathogenic conditions. However, delicate interplay between cytokines, angiogenic factors, and PlGF has more to be studied when considering their complementary role in actual pathogenic conditions. Understanding the complex interactions among these factors provides valuable insights for the development of innovative therapies for RA and MS, offering hope for improved patient outcomes.

Current and future developments in the pharmacology of asthma and COPD: ERS seminar, Naples 2022

Pharmacological management of airway obstructive diseases is a fast-evolving field. Several advances in unravelling disease mechanisms as well as intracellular and molecular pathways of drug action have been accomplished. While the clinical translation and implementation of in vitro results to the bedside remains challenging, advances in comprehending the mechanisms of respiratory medication are expected to assist clinicians and scientists in identifying meaningful read-outs and designing clinical studies. This European Respiratory Society Research Seminar, held in Naples, Italy, 5-6 May 2022, focused on current and future developments of the drugs used to treat asthma and COPD; on mechanisms of drug action, steroid resistance, comorbidities and drug interactions; on prognostic and therapeutic biomarkers; on developing novel drug targets based on tissue remodelling and regeneration; and on pharmacogenomics and emerging biosimilars. Related European Medicines Agency regulations are also discussed, as well as the seminar's position on the above aspects.

Inhibition Ras/MEK/ERK pathway: An important mechanism of Baihu Jia Guizhi Decoction ameliorated rheumatoid arthritis

ETHNOPHARMACOLOGICAL RELEVANCE

Alleviating rheumatism by inhibiting synovitis is a routine treatment for rheumatoid arthritis (RA). Baihu Jia Guizhi Decoction (BHJGZ) is a classic prescription and has a long history of application for treating RA with a good anti-inflammatory action. However, the underlying molecular mechanisms have not been fully elucidated.

AIM OF THE STUDY

This work aimed to decipher the potential mechanism of BHJGZ against RA focusing on Ras/MEK/ERK pathway.

MATERIALS AND METHODS

Based on the prediction of network pharmacology, the inhibition action of BHJGZ on Ras/MEK/ERK pathway was firstly validated in vivo and in vitro. Moreover, the affinity with the ingredients of BHJGZ in serum and the targets of Ras/MEK/ERK pathway were evaluated. Finally, the efficacy of BHJGZ for relieving RA was assessed in AA rats.

RESULTS

The Ras/MEK/ERK pathway was predicted by network pharmacology as one of important mechanisms of BHJGZ to treat RA. The high expression of Ras protein in synovitis of AA rats was significantly reduced by the treatment with BHJGZ, and the activation of Ras/MEK/ERK pathway in vivo and in vitro was also markedly inhibited (p < 0.05 or p < 0.01). Moreover, the level of p-ERK/ERK, IL-6 and TNF-α in vitro were further suppressed after Ras or MEK was inhibited by mirdametinib or lonafarnib respectively (p < 0.01). Furthermore, the results of molecular docking showed a good affinity and stable binding with the ingredients of BHJGZ in serum and multiple key proteins of the Ras/MEK/ERK pathway. Finally, paw swelling, paw circumference and pathological changes of joint synovitis were significantly reduced by BHJGZ in AA rats (p < 0.05).

CONCLUSION

The inhibition of Ras/MEK/ERK pathway is one of crucial mechanisms of BHJGZ for ameliorating synovitis of RA.

Composing On-Program Triggers and On-Demand Stimuli into Biosensor Drug Carriers in Drug Delivery Systems for Programmable Arthritis Therapy

Medication in arthritis therapies is complex because the inflammatory progression of rheumatoid arthritis (RA) and osteoarthritis (OA) is intertwined and influenced by one another. To address this problem, drug delivery systems (DDS) are composed of four independent exogenous triggers and four dependent endogenous stimuli that are controlled on program and induced on demand, respectively. However, the relationships between the mechanisms of endogenous stimuli and exogenous triggers with pathological alterations remain unclear, which results in a major obstacle in terms of clinical translation. Thus, the rationale for designing a guidance system for these mechanisms via their key irritant biosensors is in high demand. Many approaches have been applied, although successful clinical translations are still rare. Through this review, the status quo in historical development is highlighted in order to discuss the unsolved clinical difficulties such as infiltration, efficacy, drug clearance, and target localisation. Herein, we summarise and discuss the rational compositions of exogenous triggers and endogenous stimuli for programmable therapy. This advanced active pharmaceutical ingredient (API) implanted dose allows for several releases by remote controls for endogenous stimuli during lesion infections. This solves the multiple implantation and local toxic accumulation problems by using these flexible desired releases at the specified sites for arthritis therapies.

Natural medicines of targeted rheumatoid arthritis and its action mechanism

Rheumatoid arthritis (RA) is an autoimmune disease involving joints, with clinical manifestations of joint inflammation, bone damage and cartilage destruction, joint dysfunction and deformity, and extra-articular organ damage. As an important source of new drug molecules, natural medicines have many advantages, such as a wide range of biological effects and small toxic and side effects. They have become a hot spot for the vast number of researchers to study various diseases and develop therapeutic drugs. In recent years, the research of natural medicines in the treatment of RA has made remarkable achievements. These natural medicines mainly include flavonoids, polyphenols, alkaloids, glycosides and terpenes. Among them, resveratrol, icariin, epigallocatechin-3-gallate, ginsenoside, sinomenine, paeoniflorin, triptolide and paeoniflorin are star natural medicines for the treatment of RA. Its mechanism of treating RA mainly involves these aspects: anti-inflammation, anti-oxidation, immune regulation, pro-apoptosis, inhibition of angiogenesis, inhibition of osteoclastogenesis, inhibition of fibroblast-like synovial cell proliferation, migration and invasion. This review summarizes natural medicines with potential therapeutic effects on RA and briefly discusses their mechanisms of action against RA.