NF-kappa B in rheumatoid arthritis: a pivotal regulator of inflammation, hyperplasia, and tissue destruction

A synergistic effect of triptolide and curcumin on rheumatoid arthritis by improving cell proliferation and inducing cell apoptosis via inhibition of the IL-17/NF-κB signaling pathway

Rheumatoid arthritis (RA) is a chronic, progressive, systemic autoimmune disease. While triptolide (TPL) and curcumin (CUR) are known to have multiple beneficial effects on RA, the combined effect of TPL and CUR remains unexplored. This study aimed to investigate their synergistic effect on cell proliferation and apoptosis via the IL-17/NF-κB signaling pathway. The collagen-induced arthritis (CIA) rat model was established, showing severe joint and synovial damage compared to normal rats. Treatment with TPL and CUR reduced the severity of RA in the CIA rat model and alleviated serum inflammatory cytokines, such as rheumatoid factor, IL-17, TNF-α, IL-1β, and IL-6. The elevated levels of IL-17 and NF-κB in CIA rats were also inhibited, and the resistant apoptosis was aggravated by TPL and CUR. In vitro, the improvement of cell proliferation and induction of apoptosis were observed in LPS-stimulated MH7A cells treated with TPL and CUR, associated with the inhibition of the IL-17/NF-κB signaling pathway. Taken together, a synergistic effect of TPL and CUR on RA may involve relieving symptoms, improving excessive proliferation, inducing apoptosis resistance, and inhibiting the IL-17/NF-κB signaling pathway.

Clo-miR-14: a medicinally valued spice-derived miRNA with therapeutic implications in rheumatoid arthritis

Plant microRNAs (miRNA) are regularly consumed orally along with diet, gaining attention for their RNA-based drug potential because of their ability to regulate mammalian gene expression specifically at the post-transcriptional level. Medicinally valued plants are well known for their anti-inflammatory property; however, the contribution of their miRNA in managing inflammation has been less studied. We investigated miRNA from four medicinally valued regularly consumed spices, and validated one of the most potential miRNA 'Clo-miR-14' for its thermal stability, and absorption in the plasma samples of RA patient's by RT-PCR. In vitro and in vivo studies were performed to investigate the effect of Clo-miR-14 in ameliorating rheumatoid arthritis (RA) like symptoms. Our results suggest that 'Clo-miR-14,' an exogenous miRNA present in Curcuma longa, absorbed through regular diet, has robust thermal stability at 100°C in humans. It significantly reduced pro-inflammatory cytokines (TNF, IL-1β, IL-6) and RA-like symptoms, suggesting that plant-based miRNA could be a promising candidate as an RNA-based drug for RA pathogenesis.

Withaferin A alleviates inflammation in animal models of arthritis by inhibiting the NF-κB pathway and cytokine release

Withaferin A, a steroid lactone from Withania somnifera, exhibits anti-inflammatory, immunomodulatory, and antioxidant properties. This study investigated the effects of withaferin A on collagen-induced arthritis (CIA) rats, focusing on NF-κB p65 regulation and cytokine release. Withaferin A (50 mg/kg b.wt., orally) or methotrexate (0.25 mg/kg b.wt., i.p., as a reference drug) was given to CIA rats daily for 20 days postarthritis induction. Joints were removed from nonarthritic and arthritic rats to assess the levels of NO, MPO, interleukin (IL)-1β, IL-6, IL-10, TNF-α, COX-2, and NF-κB via ELISA. Furthermore, the mRNA expression of IL-1β, IL-10, TNF-α, COX-2, iNOS, and NF-κB was also assessed through qPCR. Treatment with withaferin A significantly inhibited the levels of inflammatory cytokines and the transcription factor NF-κB; suppressed the expression of IL-1β, IL-10, TNF-α, COX-2, iNOS, and NF-κB in the joint tissue of CIA rats; and reduced cartilage and bone destruction, as shown by H&E staining. To confirm the results obtained from biochemical and molecular studies and to determine the molecular target of withaferin A, we performed a molecular simulation of the potential targets of withaferin A, which identified the NF-κB pathway as its target. These results suggested that withaferin A effectively attenuated rheumatoid arthritis progression by inhibiting the activation of the NF-κB pathway and the downstream secretion of inflammatory cytokines.

Effects of oral contraceptives and menopausal hormone therapy on the risk of rheumatoid arthritis: a prospective cohort study

OBJECTIVES

Oral contraceptives (OC) and menopausal hormone therapy (MHT) contain exogenous sex hormones and are used by millions of women around the world. However, their effect on the development of rheumatoid arthritis (RA) is still debated and the current literature suggests that they may exert opposite effects on the risk of RA. The present study aimed to estimate the effects of exogenous hormones on the development of RA, both during the reproductive lifespan and later in life.

METHODS

The association between OC and RA, as well as between MHT and late-onset RA (LORA), was investigated using time-dependent Cox regression modelling in white British women from the UK Biobank (n = 236 602 and n = 102 466, respectively) and replicated in women from all ethnic groups.

RESULTS

OC use was associated with a decreased risk of RA in ever-users [hazard ratio (HR) = 0.89; 95% CI = 0.82-0.96], as well as in current (HR = 0.81; 0.73-0.91) and former users (HR = 0.92; 0.84 -1.00), compared with never-users. In contrast, MHT use was associated with an increased risk of LORA in ever-users (HR = 1.16; 1.06-1.26) as well as in former users (HR = 1.13; 1.03-1.24) compared with never-users.

CONCLUSION

OC use appears to protect against RA, while MHT may increase the risk of LORA. This study provides new insights into the possible inverse effect of exposure to different exogenous sex hormones on the risk of RA.

A chlorogenic acid-conjugated nanomicelle attenuates disease severity in experimental arthritis

Rheumatoid arthritis (RA) is a systemic immune disorder marked by synovitis, bone damage, and cartilage erosion, leading to increased socio-economic burdens and reduced quality of life. Despite its unknown cause, advancements in understanding its pathophysiology have facilitated novel therapeutic approaches. Current treatments, including disease-modifying anti-rheumatic drugs (DMARDs) and biologics, often result in low efficacy and unnecessary side effects. To address the limitations of these drugs, carrier-based drug delivery systems, such as nanomicelles, have emerged as a promising solution. In this study, nanomicelles were synthesised utilizing PLGA (poly(lactic-co-glycolic acid)) as a backbone; this backbone is conjugated with chlorogenic acid (CGA), which is known for suppressing inflammation, and incorporates methotrexate (MTX), a model drug that is established for RA treatment. The nanomicelles were extensively characterized in terms of size, charge, drug loading, and drug-release behaviour. The in vivo assessment of MTX-PLGA-b-CGA nanomicelles in a collagen-induced arthritis model demonstrated a remarkable reduction in joint swelling, cartilage erosion, and disease severity. Furthermore, histological findings confirmed cartilage integrity and reduced expression of key pro-inflammatory markers, including receptor activator of nuclear factor kappa beta ligand (RANKL) and tumor necrosis factor (TNF-α). The approach based on the MTX-PLGA-b-CGA nanomicelles presents a biocompatible and potentially effective therapeutic strategy for management of the severity and progression of RA, providing a hopeful alternative for RA treatment.

A bioactive and biodegradable vitamin C stearate-based injectable hydrogel alleviates experimental inflammatory arthritis

Rheumatoid arthritis (RA) is a chronic autoimmune inflammatory joint disorder affecting nearly 1% of the global population. In RA, synovial joints are infiltrated by inflammatory mediators and enzymes, leading to articular cartilage deterioration, joint damage, and bone erosion. Herein, the 9-aminoacridine-6-O-stearoyl-L-ascorbic acid hydrogel (9AA-SAA hydrogel) was formulated by the heat-cool method and further characterized for surface charge, surface morphology, rheology, and cytocompatibility. Furthermore, we evaluated the therapeutic efficacy of the 9AA-SAA hydrogel, an enzyme-responsive drug delivery system with on-and-off switching capabilities based on disease severity against collagen-induced experimental arthritis in Wistar rats. The anti-inflammatory action of the US FDA-approved drug 9-aminoacridine (9AA) was revealed which acted through nuclear receptor subfamily 4 group A member 1 (NR4A1), an anti-inflammatory orphan nuclear receptor that inhibits nuclear factor kappa-light-chain-enhancer of activated B cells (NF-kB). Furthermore, we have explored the role of ascorbic acid, an active moiety of 6-O-stearoyl-L-ascorbic acid (SAA), in promoting the production of collagen production through ten-eleven translocation-2 (TET2) upregulation. Targeting through NR4A1 and TET2 could be the probable mechanism for the treatment of experimental arthritis. The combination of 9AA and ascorbic acid demonstrated enhanced therapeutic efficacy in the 9AA-SAA hydrogel, significantly reducing the severity of experimental arthritis. This approach, in contrast to existing treatments with limited effectiveness, presents a promising and more effective strategy for RA treatment by mitigating inflammation in experimental arthritis.

CLK2 mediates IκBα-independent early termination of NF-κB activation by inducing cytoplasmic redistribution and degradation

Activation of the NF-κB pathway is strictly regulated to prevent excessive inflammatory and immune responses. In a well-known negative feedback model, IκBα-dependent NF-κB termination is a delayed response pattern in the later stage of activation, and the mechanisms mediating the rapid termination of active NF-κB remain unclear. Here, we showed IκBα-independent rapid termination of nuclear NF-κB mediated by CLK2, which negatively regulated active NF-κB by phosphorylating the RelA/p65 subunit of NF-κB at Ser180 in the nucleus to limit its transcriptional activation through degradation and nuclear export. Depletion of CLK2 increased the production of inflammatory cytokines, reduced viral replication and increased the survival of the mice. Mechanistically, CLK2 phosphorylated RelA/p65 at Ser180 in the nucleus, leading to ubiquitin‒proteasome-mediated degradation and cytoplasmic redistribution. Importantly, a CLK2 inhibitor promoted cytokine production, reduced viral replication, and accelerated murine psoriasis. This study revealed an IκBα-independent mechanism of early-stage termination of NF-κB in which phosphorylated Ser180 RelA/p65 turned off posttranslational modifications associated with transcriptional activation, ultimately resulting in the degradation and nuclear export of RelA/p65 to inhibit excessive inflammatory activation. Our findings showed that the phosphorylation of RelA/p65 at Ser180 in the nucleus inhibits early-stage NF-κB activation, thereby mediating the negative regulation of NF-κB.

Exploring the therapeutic potential of regulatory T cell in rheumatoid arthritis: Insights into subsets, markers, and signaling pathways

Rheumatoid arthritis (RA) is a complex autoimmune inflammatory rheumatic disease characterized by an imbalance between immunological reactivity and immune tolerance. Regulatory T cells (Tregs), which play a crucial role in controlling ongoing autoimmunity and maintaining peripheral tolerance, have shown great potential for the treatment of autoimmune inflammatory rheumatic diseases such as RA. This review aims to provide an updated summary of the latest insights into Treg-targeting techniques in RA. We focus on current therapeutic strategies for targeting Tregs based on discussing their subsets, surface markers, suppressive function, and signaling pathways in RA.

Medical treatment of osteoarthritis: botanical pharmacologic aspect

Osteoarthritis (OA) is the most common form of arthritis, and its prevalence is expected to further increase as our society ages. Despite many approaches to cure OA, no drugs are currently proven to modulate the progression of OA. Nowadays, new OA treatment options are holistically developed and one of the approaches of treatment option is botanical drugs. Some botanical drugs for OA have shown both therapeutic effect comparable to refined drugs in small studies and fewer side effects. Hence, there are various health functional foods which are known to relieve symptoms of OA. However, since there are many botanical products, clinicians are not familiar to the efficacy of each botanical product, making it challenging to use them appropriately in clinical practice. Here, we summarize the botanical products available for treating OA, including prescription botanical drugs and health functional foods available in Korea. Further studies and the purification of effective molecules from botanical products will be necessary in future.

Flavipin from fungi as a potential inhibitor of rheumatoid arthritis signaling molecules

Flavipin, a fungal lower molecular weight biomolecule (MW 196.16 g/mol), has not been yet extensively studied for beneficial preclinical and clinical applications. In recent years, various preclinical mouse models including adjuvant-induced arthritis (AIA) were employed to understand mechanisms associated with Rheumatoid arthritis (RA) and to develop new therapeutic drugs. In the current study, we studied the inhibitory effect of Flavipin on major signaling molecules involved in the inflammatory response during RA using both in-silico virtual interaction and in vivo mouse model of AIA. Our in-silico results clarified that Flavipin interacts with the tumor necrosis factor alpha (TNF-α) through conventional hydrogen binding (H-H) at one of TNF-α critical amino acids tyrosine residues, Tyr119, with binding energy (b.e.) -5.9. In addition, Flavipin binds to ATP-binging sites of the Jesus kinases, JAK1, JAK2 and JAK3, through H-H (b. e. between -5.8 and -6.1) and then it may inhibit JAKs, regulators of RA signaling molecules. Moreover, our molecular dynamics stimulation for the docked TNF-α/Flavipin complex confirmed the specificity and the stability of the interaction. In vitro, Flavipin is not toxic to normal cells at doses below 50 µM (its IC50 in normal fibroblast cell line was above 100 µM). However, in vivo, the arthritis score and hind paw oedema parameters were modulated in Flavipin treated mice. Consistent with the in-silico results the levels of the TNF-α, the nuclear transcription factor kappaB (NF-κB) and the signal transduction and activator of transcription (STAT3, downstream of JAKs) were modulated at joint tissues of the hind-paw of Flavipin/AIA treated mice. Our data suggest Flavipin as a potential therapeutic agent for arthritis can inhibit RA major signaling molecules.

An Overview of Therapeutic Targeting of Nrf2 Signaling Pathway in Rheumatoid Arthritis

Rheumatoid arthritis (RA), an autoimmune condition that has a significant inflammatory component and is exacerbated by dysregulated redox-dependent signaling pathways. In RA, the corelationship between oxidative stress and inflammation appears to be regulated by the nuclear factor erythroid 2-related factor 2 (Nrf2) signaling pathway. Furthermore, it has been shown that transcriptional pathways involving Nrf2 and NFκB significantly interact under conditions of oxidative stress and inflammation. Because pathologic cells in RA have a higher chance of surviving, Nrf2's influence on concomitant pathologic mechanisms in the disease is explained by its interaction with key redox-sensitive inflammatory pathways. The current review not only updates knowledge about Nrf2's function in RA but also highlights the complex interactions between Nrf2 and other redox-sensitive transcription factors, which are essential to the self-sustaining inflammatory processes that define RA. This paper also reviews the candidates for treating RA through Nrf2 activation. Finally, future directions for pharmacologic Nrf2 activation in RA are suggested.

NF-κB in biology and targeted therapy: new insights and translational implications

NF-κB signaling has been discovered for nearly 40 years. Initially, NF-κB signaling was identified as a pivotal pathway in mediating inflammatory responses. However, with extensive and in-depth investigations, researchers have discovered that its role can be expanded to a variety of signaling mechanisms, biological processes, human diseases, and treatment options. In this review, we first scrutinize the research process of NF-κB signaling, and summarize the composition, activation, and regulatory mechanism of NF-κB signaling. We investigate the interaction of NF-κB signaling with other important pathways, including PI3K/AKT, MAPK, JAK-STAT, TGF-β, Wnt, Notch, Hedgehog, and TLR signaling. The physiological and pathological states of NF-κB signaling, as well as its intricate involvement in inflammation, immune regulation, and tumor microenvironment, are also explicated. Additionally, we illustrate how NF-κB signaling is involved in a variety of human diseases, including cancers, inflammatory and autoimmune diseases, cardiovascular diseases, metabolic diseases, neurological diseases, and COVID-19. Further, we discuss the therapeutic approaches targeting NF-κB signaling, including IKK inhibitors, monoclonal antibodies, proteasome inhibitors, nuclear translocation inhibitors, DNA binding inhibitors, TKIs, non-coding RNAs, immunotherapy, and CAR-T. Finally, we provide an outlook for research in the field of NF-κB signaling. We hope to present a stereoscopic, comprehensive NF-κB signaling that will inform future research and clinical practice.

Rheumatoid arthritis molecular targets and their importance to flavonoid-based therapy

Rheumatoid arthritis (RA) is a progressive, chronic, autoimmune, inflammatory, and systemic condition that primarily affects the synovial joints and adjacent tissues, including bone, muscle, and tendons. The World Health Organization recognizes RA as one of the most prevalent chronic inflammatory diseases. In the last decade, there was an expansion on the available RA therapeutic options which aimed to improve patient's quality of life. Despite the extensive research and the emergence of new therapeutic approaches and drugs, there are still significant unwanted side effects associated to these drugs and still a vast number of patients that do not respond positively to the existing therapeutic strategies. Over the years, several references to the use of flavonoids in the quest for new treatments for RA have emerged. This review aimed to summarize the existing literature about the flavonoids' effects on the major pathogenic/molecular targets of RA and their potential use as lead compounds for the development of new effective molecules for RA treatment. It is demonstrated that flavonoids can modulate various players in synovial inflammation, regulate immune cell function, decrease synoviocytes proliferation and balance the apoptotic process, decrease angiogenesis, and stop/prevent bone and cartilage degradation, which are all dominant features of RA. Although further investigation is necessary to determine the effectiveness of flavonoids in humans, the available data from in vitro and in vivo models suggest their potential as new disease-modifying anti-rheumatic drugs. This review highlights the use of flavonoids as a promising avenue for future research in the treatment of RA.

Protective effect of olopatadine hydrochloride against LPS-induced acute lung injury: via targeting NF-κB signaling pathway

BACKGROUND

Morbidity and mortality rates associated with acute lung injury/acute respiratory distress syndrome (ALI/ARDS) are high (30-40%). Nuclear factor-kappa B (NF-κB) is a transcription factor, associated with transcription of numerous cytokines leading to cytokine storm, and thereby, plays a major role in ALI/ARDS and in advanced COVID-19 syndrome.

METHODS

Considering the role of NF-κB in ALI, cost-effective in silico approaches were utilized in the study to identify potential NF-κB inhibitor based on the docking and pharmacokinetic results. The identified compound was then pharmacologically validated in lipopolysaccharide (LPS) rodent model of acute lung injury. LPS induces ALI by altering alveolar membrane permeability, recruiting activated neutrophils and macrophages to the lungs, and compromising the alveolar membrane integrity and ultimately impairs the gaseous exchange. Furthermore, LPS exposure is associated with exaggerated production of various proinflammatory cytokines in lungs.

RESULTS

Based on in silico studies Olopatadine Hydrochloride (Olo), an FDA-approved drug was found as a potential NF-κB inhibitor which has been reported for the first time, and considered further for the pharmacological validation. Intraperitoneal LPS administration resulted in ALI/ARDS by fulfilling 3 out of the 4 criteria described by ATS committee (2011) published workshop report. However, treatment with Olo attenuated LPS-induced elevation of proinflammatory markers (IL-6 and NF-κB), oxidative stress, neutrophil infiltration, edema, and damage in lungs. Histopathological studies also revealed that Olo treatment significantly ameliorated LPS-induced lung injury, thus conferring improvement in survival. Especially, the effects produced by Olo medium dose (1 mg/kg) were comparable to dexamethasone standard.

CONCLUSION

In nutshell, inhibition of NF-κB pathway by Olo resulted in protection and reduced mortality in LPS- induced ALI and thus has potential to be used clinically to arrest disease progression in ALI/ARDS, since the drug is already in the market. However, the findings warrant further extensive studies, and also future studies can be planned to elucidate its role in COVID-19-associated ARDS or cytokine storm.

Dietary oleacein, a secoiridoid from extra virgin olive oil, prevents collagen-induced arthritis in mice

Olacein (OLA), one of the main secoiridoids derived from extra virgin olive oil (EVOO), has been shown to modulate oxidative and inflammatory responses in various pathological conditions; however, its potential benefit in joint disorders such as rheumatoid arthritis (RA) is unknown. Therefore, this study was designed to evaluate the preventive role of the effects of an OLA-supplemented diet in the murine model of collagen-induced arthritis (CIA), delving into the possible mechanisms and signaling pathways involved. Animals were fed an OLA-enriched preventive diet for 6 weeks prior to CIA induction and until the end of the experimental time course. On day 43 after the first immunization, mice were sacrificed: blood was collected, and paws were histologically and biochemically processed. Dietary OLA prevented collagen-induced rheumatic bone, joint and cartilage conditions. Circulating matrix metalloproteinase (MMP)-3 and proinflammatory cytokine (IL-6, IL-1β, TNF-α, IL-17) levels were significantly decreased in the joint, as well as MMP-9 and cathepsin-K (CatK) expression in secoiridoid-fed animals. In addition, dietary OLA was able to decrease COX-2, mPGES-1 and iNOS protein expressions and, also, PGE2 levels. The mechanisms possibly involved in these protective effects could be related to the activation of the Nrf-2/HO-1 axis and the inhibition of proinflammatory signaling pathways, including JAK-STAT, MAPKs and NF-κB, involved in the production of inflammatory and oxidative mediators. These results support the interest of OLA, as a nutraceutical intervention, in the management of RA.

Analysis of anti-rheumatic activity of Nyctanthes arbor-tristis via in vivo and pharmacovigilance approaches

Introduction: Rheumatoid arthritis (RA) is an immune-mediated disease associated with chronic inflammation of numerous joints. Nyctanthes arbor-tristis (NAT) is a traditional remedy for RA, a chronic inflammatory disorder. Aim: The current project aims to demonstrate the role of the NAT extracts in sub-acute toxicity, pharmacovigilance, and anti-rheumatic biomarkers. Method: Hydroethanolic extract (1:1) of plant leaves was prepared by using the reflux method. The safety of the dose was evaluated in Sprague-Dawley rats, and the anti-inflammatory effects of NAT on RA symptoms, including paw volumes, body weight, arthritic index, withdrawal latency, hematology and serological test, radiology, and histopathology, were evaluated in Freund's complete adjuvant (FCA)-induced arthritis Sprague-Dawley rat models. The inflammatory (TNF-α and COX-2) and anti-inflammatory markers (IL-10) were analyzed in control and experimental groups. Result: The study showed that 500 mg/kg BW NAT leaf extract was found to be least toxic without showing any subacute toxicity symptoms. The pharmacovigilance study highlighted the potential side effects of NAT, such as drowsiness, sedation, and lethargy, at high dosages. Treatment with the plant extract mitigated paw edema, restored the immune organ and body weights, and ameliorated the level of blood parameters such as hemoglobin, red blood cells, platelets, white blood cells, aspartate aminotransferase (AST), alanine transaminase (ALT), C-reactive proteins, and rheumatoid factor. Treatment with the plant extracts also reduced the level of cyclooxygenase 2 and TNF-α and increased the level of IL-10 in the serum of arthritic rats dose-dependently. Radiographic analysis of the ankle joint showed an improvement in the hind legs. Histological examination of the ankle joints revealed that the plant extract treatment decreased pannus formation, inflammation, and synovial hyperplasia in arthritic animals. Conclusion: NAT 500 mg/kg could serve as a promising therapeutic option for the treatment of inflammatory arthritis.

Time and dose-dependent effect of systemic glucocorticoids on major adverse cardiovascular event in patients with rheumatoid arthritis: a population-based study

OBJECTIVES

Cardiovascular event (CVE) risk in rheumatoid arthritis (RA) was increased by glucocorticoids (GC) use. Whether there is a threshold dose and duration of GC use beyond which will increase CVE rate remains controversial. We studied the time-varying effect of GC and its dose on the risk of incident major adverse cardiovascular events (MACE) in patients with RA.

METHODS

Patients with RA without MACE at baseline were recruited from a Hong Kong citywide database from 2006 to 2015 and followed till 2018. The primary outcome was the first occurrence of an MACE. Cox regression and inverse probability treatment weighting analyses with time-varying covariates were used to evaluate the association of GC and MACE, adjusting for demographics, traditional CV risk factors, inflammatory markers and the usage of antirheumatic drugs.

RESULTS

Among 12 233 RA patients with 105 826 patient-years of follow-up and a mean follow-up duration of 8.7 years, 860 (7.0%) developed MACE. In the time-varying analyses after controlling for confounding factors, a daily prednisolone dose of ≥5 mg significantly increased the risk of MACE (erythrocyte sedimentation rate model: HR 2.02, 95% CI 1.72 to 2.37; C reactive protein model: HR 1.87, 95% CI 1.60 to 2.18), while a daily dose below 5 mg was not associated with MACE risk, compared with no GC use. In patients receiving daily prednisolone ≥5 mg, the risk of incident MACE was increased by 7% per month.

CONCLUSIONS

GC was associated with a duration and dose-dependent increased risk of MACE in patients with RA. Very low dose prednisolone (<5 mg daily) did not appear to confer excessive CV risk.

Geraniol Suppresses Oxidative Stress, Inflammation, and Interstitial Collagenase to Protect against Inflammatory Arthritis

Geraniol (GER) is a plant-derived acyclic isoprenoid monoterpene that has displayed anti-inflammatory effects in numerous in vivo and in vitro models. This study was therefore designed to evaluate the antiarthritic potential of GER in complete Freund's adjuvant (CFA)-induced inflammatory arthritis (IA) model in rats. IA was induced by intraplantar injection of CFA (0.1 mL), and a week after CFA administration, rats were treated with various doses of methotrexate (MTX; 1 mg/kg) or GER (25, 50, and 100 mg/kg). Treatments were given on every alternate day, and animals were sacrificed on the 35th day. Paw volume, histopathological, hematological, radiographic, and qPCR analyses were performed to analyze the severity of the disease. GER significantly reduced paw edema after 35 days of treatment, and these results were comparable to the MTX-treated group. GER-treated animals displayed a perfect joint structure with minimal inflammation and no signs of cartilage or bone damage. Moreover, GER restored red blood cell and hemoglobin levels, normalized erythrocyte sedimentation rate, platelet, and c-reactive protein values, and also attenuated the levels of rheumatoid factor. RT-qPCR analysis demonstrated that GER decreased mRNA expression of pro-inflammatory cytokines like tumor necrosis factor-alpha (TNF-α) and interleukin-1 beta. GER also down-regulated the transcript levels of cyclooxygenase-2 (COX-2), microsomal prostaglandin E synthase-1, prostaglandin D2 synthase, and interstitial collagenase (MMP-1). Molecular docking of GER with COX-2, TNF-α, and MMP-1 also revealed that the antiarthritic effects of GER could be due to its direct interactions with these mediators. Based on our findings, it is conceivable that the antiarthritic effects of GER could be attributed to downregulation of pro-inflammatory mediators and protease like MMP-1.

Nanocomposite Hydrogels and Extracellular Matrix-Advantages and Associated Risks

Hydrogels can be considered as mimics of the extracellular matrix (ECM). Through integrins, the cytoskeleton is connected to the ECM, and cytoskeleton tension depends on ECM stiffness. A number of age-related diseases depend on cellular processes related to cytoskeleton function. Some examples of cancer initiation and progression and heart disease in relation to ECM stiffness have been analyzed. The incorporation of rigid particles into the ECM can increase ECM stiffness and promote the formation of internal residual stresses. Water migration, changes in water binding energy to biomactomolecules, and changes in the state of water from tightly bound water to free and loosely bound water lead to changes in the stiffness of the ECM. Cardiac tissue engineering, ECM stiffness and cancer, the equivalence of ECM stiffness, oxidative stress, inflammation, multi-layer polyelectrolyte complex hydrogels and bioprinting, residual internal stresses, viscoelastic hydrogels, hydrogel nanocomposites, and the effect of water have been reported. Special attention has been paid to the role of bound water and internal stresses in ECM stiffness. The risks related to rigid particle incorporation into the ECM have been discussed. The potential effect of polyphenols, chitosan, and chitosan oligosaccharide on ECM stiffness and the potential for anti-TNF-α and anti-NF-κB therapies have been discussed.

Global scientific trends update on macrophage polarization in rheumatoid arthritis: A bibliometric and visualized analysis from 2000 to 2022

The goal of this work was to use bibliometric analysis to help guide future research on macrophage polarization in RA. We looked for studies on macrophage polarization in RA published between January 1, 2000, and December 31, 2022, in the WoSCC database. Research trends and hotspots were shown and assessed using VOSviewer and CiteSpace. A total of 181 articles were gathered. Belgium was among the early adopters of the field. Chinese institutes have produced the most research. Researchers such as Angel Luis Corb, Amaya Puig-Kröger, and Lizbeth Estrada-Capetillo have made major contributions to the field. Frontiers in Immunology has published the most study findings. According to VOSviewer, the most investigated immune cells, biomarkers, and signaling pathways in the previous three years have been "T cells", "gm-csf", and "nf-κb" in that order. We discovered that the most often used terms in the previous three years were "pathway", "oxidative stress", "extracellular capsule" and "nlrp3 inflammasome" using Citespace. We emphasize these concepts in our findings, presenting the exact mechanisms of pathophysiology related to macrophage polarization in RA, as well as current breakthroughs in therapy strategies.

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.

Phytochemical mediated modulation of COX-3 and NFκB for the management and treatment of arthritis

In this study, we investigated whether zerumbone (ZBN), ellagic acid (ELA) and quercetin (QCT), the plant-derived components, can modulate the role of COX-3 or cytokines liable in arthritic disorder. Initially, the effect of ZBN, ELA, and QCT on inflammatory process was investigated using in-vitro models. In-silico docking and molecular dynamics study of these molecules with respective targets also corroborate with in-vitro studies. Further, the in-vivo anti-arthritic potential of these molecules in Complete Freund's adjuvant (CFA)-induced arthritic rats was confirmed. CFA increases in TNF-α and IL-1β levels in the arthritic control animals were significantly (***p < 0.001) attenuated in the ZBN- and ELA-treated animals. CFA-induced attenuation in IL-10 levels recovered under treatment. Moreover, ELA attenuated CFA-induced upregulation of COX-3 and ZBN downregulated CFA-triggered NFκB expression in arthritic animals. The bonding patterns of zerumbone in the catalytic sites of targets provide a useful hint in designing and developing suitable derivatives that can be used as a potential drug. To our best knowledge, the first time we are reporting the role of COX-3 in the treatment of arthritic disorders which could provide a novel therapeutic approach for the treatment of inflammatory disorders.

Targeting NF-κB pathway for the anti-inflammatory potential of Bhadradarvadi kashayam on stimulated RAW 264.7 macrophages

Macrophage-arbitrated inflammation is associated with the regulation of rheumatoid arthritis (RA). Low risk and better efficiency are steered herbal drugs more credible than conventional medicines in RA management. Bhadradarvadi (BDK) concoction has been traditionally used for rheumatism in Ayurveda. However, the mechanisms at the molecular level are still elusive. This study was designed to inspect the process of immunomodulation and anti-inflammatory properties of BDK in lipopolysaccharide (LPS)-stimulated RAW 264.7 macrophages for the first time. BDK concoction was prepared and evaluated with the stimulated murine macrophage-like RAW 264.7 cell lines. TNF-α, IL6, and PGE2 were quantified by ELISA. The normalization of the fold change in the expression of the target gene mRNA was done by comparing the values of the β-actin housekeeping gene using the 2-ΔΔCt comparative cycle threshold. The expression of TNF-α, IL6, iNOS, and COX-2 in the RAW 264.7 macrophage cells was analyzed using flow cytometry. Our results showed that BDK (150-350 μl/ml) treatment significantly decreased the inflammatory cytokines (TNF-α, and IL-6) and inflammatory mediators (PGE2) in LPS-stimulated RAW 264.7 macrophage cells. The pro-inflammatory cytokines (TNF-α, IL-1β, and IL-6) expression, inflammatory enzymes (iNOS and COX-2), and NF-κBp65 were significantly downregulated at transcriptome level in LPS-stimulated RAW 264.7 macrophage cells. The flow cytometry analysis revealed that BDK treatment diminished the TNF-α, IL-6, iNOS, and COX-2 expression at the proteome level, as well as obstruction of NF-κB-p65 nuclear translocation was observed by immunofluorescence analysis in LPS-stimulated RAW 264.7 macrophage cells. Collectively, BDK can intensely augment the anti-inflammatory activities via inhibiting the NF-κB signaling pathway trigger for treating autoimmune disorders including RA.

Targeting transcription factors for therapeutic benefit in rheumatoid arthritis

Rheumatoid arthritis (RA) is a destructive inflammatory autoimmune disease that causes pain and disability. Many of the currently available drugs for treating RA patients are aimed at halting the progression of the disease and alleviating inflammation. Further, some of these treatment options have drawbacks, including disease recurrence and adverse effects due to long-term use. These inefficiencies have created a need for a different approach to treating RA. Recently, the focus has shifted to direct targeting of transcription factors (TFs), as they play a vital role in the pathogenesis of RA, activating key cytokines, chemokines, adhesion molecules, and enzymes. In light of this, synthetic drugs and natural compounds are being explored to target key TFs or their signaling pathways in RA. This review discusses the role of four key TFs in inflammation, namely NF-κB, STATs, AP-1 and IRFs, and their potential for being targeted to treat RA.

Leocarpinolide B Attenuates Collagen Type II-Induced Arthritis by Inhibiting DNA Binding Activity of NF-κB

Rheumatoid arthritis (RA) is a chronic autoimmune disease triggered by a cascading inflammatory response. Sigesbeckia Herba (SH) has long been utilized as a traditional remedy to alleviate symptoms associated with rheumatism. Our previous study found that leocarpinolide B (LB), a sesquiterpene lactone isolated from the whole plant of SH, possesses potent a anti-inflammatory effect on macrophages. This study was designed to evaluate the therapeutic effects of LB on RA, and further investigate the underlying mechanisms. In collagen type II-induced arthritic mice, LB was demonstrated to decrease the production of autoimmune antibodies in serum and inflammatory cytokines in the joint muscles and recover the decreased regulatory T lymphocytes in spleen. Moreover, LB significantly suppressed the inflammatory infiltration, formation of pannus and bone erosion in the paw joints. In vitro testing showed that LB inhibited the proliferation, migration, invasion, and secretion of inflammatory cytokines in IL-1β-induced human synovial SW982 cells. Network pharmacology and molecular docking suggested NF-κB p65 could be the potential target of LB on RA treatment, subsequent experimental investigation confirmed that LB directly interacted with NF-κB p65 and reduced the DNA binding activity of NF-κB in synovial cells. In conclusion, LB significantly attenuated the collagen type II-induced arthritis, which was at least involved in the inhibition of DNA binding activity of NF-κB through a direct binding to NF-κB p65. These findings suggest that LB could be a valuable lead compound for developing anti-RA drugs.

Inhibition of BET Proteins Regulates Fcγ Receptor Function and Reduces Inflammation in Rheumatoid Arthritis

Overactivation of immune responses is a hallmark of autoimmune disease pathogenesis. This includes the heightened production of inflammatory cytokines such as Tumor Necrosis Factor α (TNFα), and the secretion of autoantibodies such as isotypes of rheumatoid factor (RF) and anticitrullinated protein antibody (ACPA). Fcγ receptors (FcγR) expressed on the surface of myeloid cells bind Immunoglobulin G (IgG) immune complexes. Recognition of autoantigen-antibody complexes by FcγR induces an inflammatory phenotype that results in tissue damage and further escalation of the inflammatory response. Bromodomain and extra-terminal protein (BET) inhibition is associated with reduced immune responses, making the BET family a potential therapeutic target for autoimmune diseases such as rheumatoid arthritis (RA). In this paper, we examined the BET inhibitor PLX51107 and its effect on regulating FcγR expression and function in RA. PLX51107 significantly downregulated expression of FcγRIIa, FcγRIIb, FcγRIIIa, and the common γ-chain, FcϵR1-γ, in both healthy donor and RA patient monocytes. Consistent with this, PLX51107 treatment attenuated signaling events downstream of FcγR activation. This was accompanied by a significant decrease in phagocytosis and TNFα production. Finally, in a collagen-induced arthritis model, PLX51107-treatment reduced FcγR expression in vivo accompanied by a significant reduction in footpad swelling. These results suggest that BET inhibition is a novel therapeutic approach that requires further exploration as a treatment for patients with RA.

NF-κB activation enhances STING signaling by altering microtubule-mediated STING trafficking

It is widely known that stimulator of interferon genes (STING) can trigger nuclear factor κB (NF-κB) signaling. However, whether and how the NF-κB pathway affects STING signaling remains largely unclear. Here, we report that Toll-like receptor (TLR)-, interleukin-1 receptor (IL-1R)-, tumor necrosis factor receptor (TNFR)-, growth factor receptor (GF-R)-, and protein kinase C (PKC)-mediated NF-κB signaling activation dramatically enhances STING-mediated immune responses. Mechanistically, we find that STING interacts with microtubules, which plays a crucial role in STING intracellular trafficking. We further uncover that activation of the canonical NF-κB pathway induces microtubule depolymerization, which inhibits STING trafficking to lysosomes for degradation. This leads to increased levels of activated STING that persist for a longer period of time. The synergy between NF-κB and STING triggers a cascade-amplified interferon response and robust host antiviral defense. In addition, we observe that several gain-of-function mutations of STING abolish the microtubule-STING interaction and cause abnormal STING trafficking and ligand-independent STING autoactivation. Collectively, our data demonstrate that NF-κB activation enhances STING signaling by regulating microtubule-mediated STING trafficking.

Fluorinated polyamidoamine dendrimer-mediated miR-23b delivery for the treatment of experimental rheumatoid arthritis in rats

In rheumatoid arthritis (RA), insufficient apoptosis of macrophages and excessive generation of pro-inflammatory cytokines are intimately connected, accelerating the development of disease. Here, a fluorinated polyamidoamine dendrimer (FP) is used to deliver miR-23b to reduce inflammation by triggering the apoptosis of as well as inhibiting the inflammatory response in macrophages. Following the intravenous injection of FP/miR-23b nanoparticles in experimental RA models, the nanoparticles show therapeutic efficacy with inhibition of inflammatory response, reduced bone and cartilage erosion, suppression of synoviocyte infiltration and the recovery of mobility. Moreover, the nanoparticles accumulate in the inflamed joint and are non-specifically captured by synoviocytes, leading to the restoration of miR-23b expression in the synovium. The miR-23b nanoparticles target Tab2, Tab3 and Ikka to regulate the activation of NF-κB pathway in the hyperplastic synovium, thereby promoting anti-inflammatory and anti-proliferative responses. Additionally, the intravenous administration of FP/miR-23b nanoparticles do not induce obvious systemic toxicity. Overall, our work demonstrates that the combination of apoptosis induction and inflammatory inhibition could be a promising approach in the treatment of RA and possibly other autoimmune diseases.

Investigating the correlation of the NF-κB and FoxP3 gene expression with the plasma levels of pro- and anti-inflammatory cytokines in rheumatoid arthritis patients

INTRODUCTION

Rheumatoid arthritis (RA) is a chronic inflammatory systemic autoimmune disease. Cytokines regulate a wide range of inflammatory processes involved in RA pathogenesis. Anti-inflammatory cytokines (i.e., TGF-β and lL-10) and pro-inflammatory cytokines, like IL-6, were found to be potentially implicated in RA pathogenesis. Besides, NF-κB and FoxP3 are critical transcription factors regulating the inflammatory events occurring in RA patients. This study intends to assess the plasma levels of IL-6, IL-10, and TGF-β1 cytokines, as well as the expression of NF-κB and FoxP3 genes in RA patients, compared to the healthy controls.

METHODS

Peripheral blood was collected from 50 RA patients (25 new case and 25 under-treatment) and 25 age- and gender-matched healthy subjects. The disease activity was determined using the DAS-28 and ESR criteria. Also, plasma levels of TGF-β1, lL-10, and IL-6 were measured by enzyme-linked immunosorbent assay (ELISA) technique, and the gene expression of NF-κB and FoxP3 was evaluated using the real-time PCR method.

RESULTS

Our results showed a significant up-regulation of Rel-A and NF-κB1, and also a down-regulation of FoxP3 gene expression in under-treatment RA patients compared to the controls (P=0.031, P=0.014, and P=0.011, respectively). Moreover, there was a significant reduction of Rel-A and FoxP3 in the under-treatment RA patients compared to new case RA patients (P=0.005 and P=0.015, respectively). Also, plasma levels of TGF-β1 were significantly increased in both the new case and under-treatment RA patients relative to controls (P<0.001).

CONCLUSION

In conclusion, classical NF-κB (P65/P50) and FoxP3 may have significant pro- and anti-inflammatory roles in RA pathogenesis, respectively. Key Point • NF-κB (P65/P50) has a contribution to the early phase of RA.

Anti-inflammatory effects of PRIMA-1MET (mutant p53 reactivator) induced by inhibition of nuclear factor-κB on rheumatoid arthritis fibroblast-like synoviocytes

Fibroblast-like synoviocytes (FLSs), the main pathological cells in rheumatoid arthritis (RA), display tumor-like phenotype, including hyper-proliferation, apoptosis resistance, and aggressive phenotype. Excessive proliferation and insufficient apoptosis of RA-FLSs can lead to hyperplastic synovial pannus tissue, excess production of inflammatory mediators, and destruction of joints. In this article, we investigate the effect of PRIMA-1^MET on the apoptosis induction and inhibition of pro-inflammatory cytokines in RA-FLSs. Synovial tissue samples were obtained from 10 patients with RA. The FLSs were treated with different concentrations of PRIMA-1^MET. The rate of apoptosis and cell survival was assessed by flow cytometry and MTT assay and Real-time quantitative PCR was performed to evaluate the transcription of p53, IL-6, IL-1β, TNF-α, Noxa, p21, PUMA, Bax, Survivin, and XIAP in treated RA-FLSs. The protein level of p53, IκBα, and phospho-IκBα were measured using Western blotting. The results showed that PRIMA-1^MET induced apoptosis in RA-FLSs and increased significantly the expression of Noxa, and decreased significantly IL-6, IL-1β, p53, and phospho-IκBα expression. PRIMA-1^MET can induce apoptosis in RA-FLSs through induction of Noxa expression while p53 was downregulated. Furthermore, PRIMA-1^MET treatment results in the suppression of pro-inflammatory cytokine production and NF-κB inhibition. Given the role of p53 and NF-κB in RA-FLSs, PRIMA-1^MET can be considered as a new therapeutic strategy for rheumatoid arthritis.

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

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

Caffeic Acid Modified Nanomicelles Inhibit Articular Cartilage Deterioration and Reduce Disease Severity in Experimental Inflammatory Arthritis

Inflammation plays an important role in the development of rheumatoid arthritis (RA). NR4A1 is an anti-inflammatory orphan nuclear receptor involved in protection from inflammatory stimuli in RA. In this study we have explored the anti-inflammatory potential of the FDA-approved drug 9-aminoacridine (9AA) and the natural compound caffeic acid (CA) conjugated to nanomicelles for the treatment of RA. We have synthesized methoxy polyethylene glycol polycaprolactone block copolymer (mPEG-b-PCL) by ring opening polymerization of ε-caprolactone. Then, we conjugated the hydrophilic caffeic acid (CA) with mPEG-b-PCL micelles via Steglich esterification and incorporated the 9AA drug. These nanomicelles were formulated by the solvent evaporation method with a size distribution around 190 nm and showed maximum drug loading capacity along with sustained drug release behavior. Furthermore, we tested the therapeutic potential of the formulated 9AA-encapsulated CA-conjugated nanomicelles (9AA-NMs) against an experimental RA model. We observed promising results which showed alleviation of arthritic symptoms by reducing inflammation, joint damage, bone erosion, and swelling. Further, collagen destruction was significantly reduced in articular cartilage, as shown by safranin-O and toluidine blue staining. The protective mechanism might be due to the simultaneous inhibition of NF-κB by 9AA and CA, whereas the activation of NR4A1 by 9AA leads to the suppression of HIF-1α. This combined therapeutic effect of 9AA and CA has enhanced the therapeutic efficacy of 9AA-NM and markedly reduced the severity of inflammatory arthritis. Unlike existing drugs for pain management and with limited efficacy, 9AA-NM exerted a disease-relevant activation/blockade that alleviated inflammation and exhibited marked therapeutic efficacy against RA.

The dichotomous outcomes of TNFα signaling in CD4+ T cells

TNFa blocking agents were the first-in-class biologic drugs used for the treatment of autoimmune disease. Paradoxically, however, exacerbation of autoimmunity was observed in some patients. TNFa is a pleiotropic cytokine that has both proinflammatory and regulatory effects on CD4+ T cells and can influence the adaptive immune response against autoantigens. Here, we critically appraise the literature and discuss the intricacies of TNFa signaling that may explain the controversial findings of previous studies. The pleiotropism of TNFa is based in part on the existence of two biologically active forms of TNFa, soluble and membrane-bound, with different affinities for two distinct TNF receptors, TNFR1 and TNFR2, leading to activation of diverse downstream molecular pathways involved in cell fate decisions and immune function. Distinct membrane expression patterns of TNF receptors by CD4+ T cell subsets and their preferential binding of distinct forms of TNFα produced by a diverse pool of cellular sources during different stages of an immune response are important determinants of the differential outcomes of TNFa-TNF receptor signaling. Targeted manipulation of TNFa-TNF receptor signaling on select CD4+ T cell subsets may offer specific therapeutic interventions to dampen inflammation while fortifying immune regulation for the treatment of autoimmune diseases.

Pros and cons of NRF2 activation as adjunctive therapy in rheumatoid arthritis

Rheumatoid arthritis (RA) is an autoimmune disease with an important inflammatory component accompanied by deregulated redox-dependent signaling pathways that are feeding back into inflammation. In this context, we bring into focus the transcription factor NRF2, a master redox regulator that exerts exquisite antioxidant and anti-inflammatory effects. The review does not intend to be exhaustive, but to point out arguments sustaining the rationale for applying an NRF2-directed co-treatment in RA as well as its potential limitations. The involvement of NRF2 in RA is emphasized through an analysis of publicly available transcriptomic data on NRF2 target genes and the findings from NRF2-knockout mice. The impact of NRF2 on concurrent pathologic mechanisms in RA is explained by its crosstalk with major redox-sensitive inflammatory and cell death-related pathways, in the context of the increased survival of pathologic cells in RA. The proposed adjunctive therapy targeted to NRF2 is further sustained by the existence of promising NRF2 activators that are in various stages of drug development. The interference of NRF2 with conventional anti-rheumatic therapies is discussed, including the cytoprotective effects of NRF2 for alleviating drug toxicity. From another perspective, the review presents how NRF2 activation would be decreasing the efficacy of synthetic anti-rheumatic drugs by increasing drug efflux. Future perspectives regarding pharmacologic NRF2 activation in RA are finally proposed.

Inhibiting peripheral and central MAO-B ameliorates joint inflammation and cognitive impairment in rheumatoid arthritis

Rheumatoid arthritis (RA) is an autoimmune disorder characterized by chronic inflammation and the destruction of joints and systemic organs. RA is commonly accompanied by neuropsychiatric complications, such as cognitive impairment and depression. However, the role of monoamine oxidase (MAO) and its inhibitors in controlling neurotransmitters associated with these complications in RA have not been clearly identified. Here, we report that peripheral and central MAO-B are highly associated with joint inflammation and cognitive impairment in RA, respectively. Ribonucleic acid (RNA) sequencing and protein expression quantification were used to show that MAO-B and related molecules, such as gamma aminobutyric acid (GABA), were elevated in the inflamed synovium of RA patients. In primary cultured fibroblast-like synoviocytes in the RA synovium, MAO-B expression was significantly increased by tumor necrosis factor (TNF)-α-induced autophagy, which produces putrescine, the polyamine substrate for GABA synthesis. We also observed that MAO-B-mediated aberrant astrocytic production of GABA was augmented by interleukin (IL)-1β and inhibited CA1-hippocampal pyramidal neurons, which are responsible for memory storage, in an animal model of RA. Moreover, a newly developed reversible inhibitor of MAO-B ameliorated joint inflammation by inhibiting cyclooxygenase (Cox)-2. Therefore, MAO-B can be an effective therapeutic target for joint inflammation and cognitive impairment in patients with RA.

Inhibiting an enzyme that is upregulated during joint inflammation may prove a valuable therapy for rheumatoid arthritis (RA). As well as causing considerable pain and discomfort in the joints, RA can also trigger neuropsychiatric problems including depression and memory impairment. The monoamine oxidase (MAO) enzyme family is involved in the control of neurotransmitters, and there is evidence that links MAO-B levels with systemic inflammation. C. Justin Lee at Center for Cognition and Sociality, Institute for Basic Science,, Daejeon, South Korea, and co-workers examined the role of MAO-B in RA using patient tissue samples and mouse models. MAO-B and related molecules were upregulated in patients’ inflamed joint tissues. In mice, elevated MAO-B triggered the inhibition of nerve cell activity related to memory storage. A novel drug that inhibits MAO-B reduced RA-related inflammation and cognitive impairment in mice, suggesting a promising approach to treatment.

Trivalent chromium supplementation ameliorates adjuvant induced rheumatoid arthritis through up-regulation of FOXP3 and decrease in synovial Cathepsin G expression

BACKGROUND

Rheumatoid arthritis (RA) is a known debilitating autoimmune disease. Immune-suppressants that are used for disease treatment have serious side effects, therefore, trivalent chromium (Cr (III)); which has shown evidence of its influences on some inflammatory pathways and cytokines; was used in this study for the first time to be assessed for its therapeutic effect in RA rat model and was compared to prednisolone in a trial to find a treatment with lesser side effects.

METHODS

Adult male albino rats were randomly divided into four groups: normal, untreated RA, prednisolone treated RA (1.25 mg/kg/day) and Cr (III) treated RA groups (80 μg/kg/day), induction of RA was done by subcutaneous complete Freund adjuvant injection. Study duration was 4 weeks throughout which arthritis scoring and weight measurement were pursued. Histopathological examination and immunohistochemical FOXP3 assessment were done for joint biopsies. Serum inflammatory markers (interleukin 17, interleukin 10, CRP) and synovial erosive arthritis marker (Cathepsin G) were measured. HDL and non-HDL cholesterol were estimated as well.

RESULTS

Cr (III) treatment showed marked clinical and histopathological improvement, also astonishing anti-inflammatory effects (increase in FOXP3 expression and interleukin 10, with decrease in interleukin 17, CRP and synovial Cathepsin G) to the extent that Cr (III) effects on inflammation abolishment were comparable to that of prednisolone and even better at some aspects. Moreover, Cr (III) was protective from side effects, i.e., weight gain and dyslipidemia that were seen with prednisolone treatment.

CONCLUSIONS

Cr (III) is promising in treating RA and it lacks some side effects of accustomed immune-modulatory agents including prednisolone. Further experimental studies and clinical trials should be held to see the efficacy of Cr (III) in different doses and to assess its long term side effects when used for rheumatoid arthritis and other autoimmune diseases treatment.

Inhibitory Effects of Cold Atmospheric Plasma on Inflammation and Tumor-Like Feature of Fibroblast-Like Synoviocytes from Patients with Rheumatoid Arthritis

Rheumatoid arthritis (RA) is a chronic, debilitating systemic disease characterized by chronic inflammation and progressive joint destruction. Fibroblast-like synoviocytes (FLSs) are one of the most important players in the pathophysiology of RA, acting like tumor cells and secreting inflammatory cytokines. Previous research has shown that cold atmospheric plasma (CAP) inhibits cancer cells and may have anti-inflammatory properties. This study examined the effects of argon plasma jet-produced CAP on the suppression of invasion and inflammation caused by cultured RA-FLS. The findings revealed that CAP reduced cell viability and elevated the percentage of apoptotic RA-FLS by producing reactive oxygen species. Carboxyfluorescein diacetate succinimidyl ester (CFSE) staining confirmed that CAP could decrease the proliferation of RA-FLS. Furthermore, CAP effectively reduced the production of inflammatory factors (e.g., NF-κB and IL-6) as well as destructive factors like receptor activator of nuclear factor kappa-B ligand (RANKL) and matrix metalloproteinases-3 (MMP-3). These data suggest that CAP could be a promising treatment for slowing the progression of RA by reducing tumor-like features and inflammation in RA-FLS.

Utility of Baseline Transcriptomic Analysis of Rheumatoid Arthritis Synovium as an Indicator for Long-Term Clinical Outcomes

Objective:

Rheumatoid arthritis is a chronic inflammatory autoimmune disease that can lead to synovial damage, persistent joint pain, and functional disability. Our objective was to evaluate baseline synovial transcriptome from early inflammatory arthritis patients (EIA) and identify pretreatment biomarkers that could potentially provide insights into long-term functional outcomes of rheumatoid arthritis (RA).

Methods

Synovial biopsies from clinically inflamed knee joints were procured from either 17 EIA patients before initiation of disease modifying anti-rheumatic drug (DMARD) therapy (DMARD-naïve EIA) using the minimally invasive closed needle biopsy technique or advanced RA patients undergoing arthroplasty. Affymetrix Human Genome U133 Plus 2 microarray platform was used to profile the synovial transcriptome. The cohort was followed clinically for a median of 12.3 years, and patient data was collected at each visit. Short-term and long-term clinical outcomes were determined by assessing RA-associated clinical parameters Statistical adjustments were made to account for asynchronous clinical visits and duration of follow up.

Results

Based on the transcriptomic analysis, we identified 5 differentially expressed genes (DEGs), including matrix metalloproteinase (MMP)-1 (fibroblast collagenase) and MMP-3 (stromelysin-1) in DMARD-naïve EIA patients, relative to advanced RA patients (q < 0.05). Dichotomous expression of MMP-1 and MMP-3 mRNA and protein was confirmed by qPCR and immunohistochemistry respectively, based on which DMARD-naïve EIA subjects were classified as MMP-high or MMP-low. Hierarchical clustering of transcriptomic data identified 947 DEGs between MMP-high and MMP-low cohorts. Co-expression and IPA analysis of DEGs in the MMP-high cohort showed an enrichment of genes that participated in metabolic or biochemical functions and intracellular immune signaling were regulated through NF-κB and β-catenin complexes and correlated with markers of systemic inflammation. Analysis of short-term clinical outcomes in MMP-high cohort showed a significant reduction in the DAS-CRP scores relative to baseline (P <0.001), whereas area under the curve analyses of modified HAQ (mHAQ) scores correlated negatively with baseline MMP-1 (R = −0.59, P = 0.03). Further, longitudinal mHAQ scores, number of swollen joints, number of DMARDs and median follow-up duration appeared to be higher in MMP-low cohort.

Conclusion

Overall, our results indicate that the gene expression profiling of synovial biopsies obtained at the DMARD-naive stage in patients with EIA categorizes them into subsets with varying degrees of inflammation and can predict the future of long-term clinical outcome.

SOX4 and RELA Function as Transcriptional Partners to Regulate the Expression of TNF- Responsive Genes in Fibroblast-Like Synoviocytes

SOX4 belongs to the group C of the SOX transcription factor family. It is a critical mediator of tumor necrosis factor alpha (TNF)-induced transformation of fibroblast-like s-ynoviocytes (FLS) in arthritis. In this study we investigated the genome wide association between the DNA binding and transcriptional activities of SOX4 and the NF-kappaB signaling transcription factor RELA/p65 downstream of TNF signaling. We used ChIP-seq assays in mouse FLS to compare the global DNA binding profiles of SOX4 and RELA. RNA-seq of TNF-induced wildtype and SoxC-knockout FLS was used to identify the SOX4-dependent and independent aspects of the TNF-regulated transcriptome. We found that SOX4 and RELA physically interact with each other on the chromatin. Interestingly, ChIP-seq assays revealed that 70.4% of SOX4 peak summits were within 50bp of the RELA peak summits suggesting that both proteins bind in close-proximity on regulatory sequences, enabling them to co-operatively regulate gene expression. By integrating the ChIP-seq results with RNA-seq from SoxC-knockout FLS we identified a set of TNF-responsive genes that are targets of the RELA-SOX4 transcriptional complex. These TNF-responsive and RELA-SOX4-depenedent genes included inflammation mediators, histone remodeling enzymes and components of the AP-1 signaling pathway. We also identified an autoregulatory mode of SoxC gene expression that involves a TNF-mediated switch from RELA binding to SOX4 binding in the 3' UTR of Sox4 and Sox11 genes. In conclusion, our results show that SOX4 and RELA together orchestrate a multimodal regulation of gene expression downstream of TNF signaling. Their interdependent activities play a pivotal role in the transformation of FLS in arthritis and in the inflammatory pathology of diverse tissues where RELA and SOX4 are co-expressed.

The Effects of Crocin on Bone and Cartilage Diseases

Crocin, the main biologically active carotenoid of saffron, generally is derived from the dried trifid stigma of Crocus sativus L. Many studies have demonstrated that crocin has several therapeutic effects on biological systems through its anti-oxidant and anti-inflammatory properties. The wide range of crocin activities is believed to be because of its ability to anchor to many proteins, triggering some cellular pathways responsible for cell proliferation and differentiation. It also has therapeutic potentials in arthritis, osteoarthritis, rheumatoid arthritis, and articular pain probably due to its anti-inflammatory properties. Anti-apoptotic effects, as well as osteoclast inhibition effects of crocin, have suggested it as a natural substance to treat osteoporosis and degenerative disease of bone and cartilage. Different mechanisms underlying crocin effects on bone and cartilage repair have been investigated, but remain to be fully elucidated. The present review aims to undertake current knowledge on the effects of crocin on bone and cartilage degenerative diseases with an emphasis on its proliferative and differentiative properties in mesenchymal stem cells.

MOSES: A New Approach to Integrate Interactome Topology and Functional Features for Disease Gene Prediction

Disease gene prediction is to date one of the main computational challenges of precision medicine. It is still uncertain if disease genes have unique functional properties that distinguish them from other non-disease genes or, from a network perspective, if they are located randomly in the interactome or show specific patterns in the network topology. In this study, we propose a new method for disease gene prediction based on the use of biological knowledge-bases (gene-disease associations, genes functional annotations, etc.) and interactome network topology. The proposed algorithm called MOSES is based on the definition of two somewhat opposing sets of genes both disease-specific from different perspectives: warm seeds (i.e., disease genes obtained from databases) and cold seeds (genes far from the disease genes on the interactome and not involved in their biological functions). The application of MOSES to a set of 40 diseases showed that the suggested putative disease genes are significantly enriched in their reference disease. Reassuringly, known and predicted disease genes together, tend to form a connected network module on the human interactome, mitigating the scattered distribution of disease genes which is probably due to both the paucity of disease-gene associations and the incompleteness of the interactome.

Association of the Adipokines Chemerin, Apelin, Vaspin and Omentin and Their Functional Genetic Variants with Rheumatoid Arthritis

Adipokines were shown to exert crucial roles in rheumatic diseases. This study aimed to assess the role of chemerin, apelin, vaspin, and omentin adipokines and their genetic variants rs17173608, rs2235306, rs2236242, and rs2274907, respectively, in rheumatoid arthritis (RA) pathogenesis in Egyptian patients. A total of 150 RA patients and 150 healthy individuals were recruited. Blood samples were collected and used for genotyping. Serum was separated and used for expression analysis by quantitative PCR, and various biochemical markers determination by ELISA. Serum protein levels of chemerin and vaspin, as well as their gene expression levels were higher, while those of apelin and omentin were lower in RA patients and were associated with most of RA clinical and laboratory characteristics. G allele of chemerin rs17173608, T allele of vaspin rs2236242, and T allele of omentin rs2274907 were more frequent in RA patients. Serum levels and gene expression levels of chemerin in GG genotype carriers and vaspin in TT genotype group were significantly higher, while those of omentin in TT genotype carriers were significantly lower than RA patients with other genotypes. There was no association between apelin rs2235306 and RA. Chemerin rs17173608, vaspin rs2236242, and omentin rs2274907 polymorphisms were associated with increased susceptibility to RA.

Kinase activity profiling reveals contribution of G-protein signaling modulator 2 deficiency to impaired regulatory T cell migration in rheumatoid arthritis

The ability of regulatory T (T_reg) cells to migrate into inflammatory sites is reduced in autoimmune diseases, including rheumatoid arthritis (RA). The reasons for impaired T_reg cell migration remain largely unknown. We performed multiplex human kinase activity arrays to explore possible differences in the post-translational phosphorylation status of kinase related proteins that could account for altered T_reg cell migration in RA. Results were verified by migration assays and Western blot analysis of CD4⁺ T cells from RA patients and from mice with collagen type II induced arthritis. Kinome profiling of CD4⁺ T cells from RA patients revealed significantly altered post-translational phosphorylation of kinase related proteins, including G-protein-signaling modulator 2 (GPSM2), protein tyrosine kinase 6 (PTK6) and vitronectin precursor (VTNC). These proteins have not been associated with RA until now. We found that GPSM2 expression is reduced in CD4⁺ T cells from RA patients and is significantly downregulated in experimental autoimmune arthritis following immunization of mice with collagen type II. Interestingly, GPSM2 acts as a promoter of T_reg cell migration in healthy individuals. Treatment of RA patients with interleukin-6 receptor (IL-6R) blocking antibodies restores GPSM2 expression, thereby improving T_reg cell migration. Our study highlights the potential of multiplex kinase activity arrays as a tool for the identification of RA-related proteins which could serve as targets for novel treatments.

Tomatidine Suppresses the Destructive Behaviors of Fibroblast-Like Synoviocytes and Ameliorates Type II Collagen-Induced Arthritis in Rats

Fibroblast-like synoviocytes (FLSs) are the prominent non-immune cells in synovium and play a pivotal role in rheumatoid arthritis (RA) pathogenesis. Searching for natural compounds that may suppress the pathological phenotypes of FLSs is important for the development of RA treatment. Tomatidine (Td), a steroidal alkaloid derived from the solanaceae family, has been reported to have anti-inflammatory, anti-tumor and immunomodulatory effects. However, its effect on RA remains unknown. Here, we examined the inhibitory effect of Td on TNFα-induced arthritic FLSs, and subsequently investigated its therapeutic effect on collagen-induced arthritis (CIA) rats. Our results revealed that Td significantly inhibited TNFα-induced proliferation and migration of arthritic FLSs. In addition, we found that Td treatment could efficaciously ameliorate synovial inflammation and joint destruction of rats with CIA. Both in vitro and in vivo studies showed that Td significantly suppressed the production of pro-inflammatory cytokines including IL-1β, IL-6 and TNFα, and downregulated the expression of MMP-9 and RANKL. Further molecular mechanism studies revealed that the inhibitory effect of Td on RA might attribute to the decreased activations of MAPKs (ERK and JNK) and NF-κB. These findings provide evidence that Td has the potential to be developed into a complementary or alternative agent for RA therapy.

Motif-Raptor: a cell type-specific and transcription factor centric approach for post-GWAS prioritization of causal regulators

MOTIVATION

Genome-wide association studies (GWASs) have identified thousands of common trait-associated genetic variants but interpretation of their function remains challenging. These genetic variants can overlap the binding sites of transcription factors (TFs) and therefore could alter gene expression. However, we currently lack a systematic understanding on how this mechanism contributes to phenotype.

RESULTS

We present Motif-Raptor, a TF-centric computational tool that integrates sequence-based predictive models, chromatin accessibility, gene expression datasets and GWAS summary statistics to systematically investigate how TF function is affected by genetic variants. Given trait-associated non-coding variants, Motif-Raptor can recover relevant cell types and critical TFs to drive hypotheses regarding their mechanism of action. We tested Motif-Raptor on complex traits such as rheumatoid arthritis and red blood cell count and demonstrated its ability to prioritize relevant cell types, potential regulatory TFs and non-coding SNPs which have been previously characterized and validated.

AVAILABILITY AND IMPLEMENTATION

Motif-Raptor is freely available as a Python package at: https://github.com/pinellolab/MotifRaptor.

SUPPLEMENTARY INFORMATION

Supplementary data are available at Bioinformatics online.

CS-semi5 Inhibits NF-κB Activation to Block Synovial Inflammation, Cartilage Loss and Bone Erosion Associated With Collagen-Induced Arthritis

Rheumatoid arthritis (RA) is a chronic, systemic autoimmune disease that affects 1% of the population. CS-semi5 is a semisynthetic chondroitin sulfate. In this study, CS-semi5 was shown to have positive effects on a model of collagen-induced arthritis (CIA). CS-semi5 treatment had obvious effects on weight loss and paw swelling in CIA mice. Post-treatment analysis revealed that CS-semi5 alleviated three main pathologies (i.e., synovial inflammation, cartilage erosion and bone loss) in a dose-dependent manner. Further study showed that CS-semi5 could effectively reduce TNF-α and IL-1β production in activated macrophages via the NF-κB pathway. CS-semi5 also blocked RANKL-trigged osteoclast differentiation from macrophages. Therefore, CS-semi5 may effectively ameliorate synovial inflammation, cartilage erosion and bone loss in RA through NF-κB deactivation.

Sclerostin-Mediated Impaired Osteogenesis by Fibroblast-Like Synoviocytes in the Particle-Induced Osteolysis Model

Engineered biomaterials are envisioned to replace, augment, or interact with living tissues for improving the functional deformities associated with end-stage joint pathologies. Unfortunately, wear debris from implant interfaces is the major factor leading to periprosthetic osteolysis. Fibroblast-like synoviocytes (FLSs) populate the intimal lining of the synovium and are in direct contact with wear debris. This study aimed to elucidate the effect of Ti particles as wear debris on human FLSs and the mechanism by which they might participate in the bone remodeling process during periprosthetic osteolysis. FLSs were isolated from synovial tissue from patients, and the condition medium (CM) was collected after treating FLSs with sterilized Ti particles. The effect of CM was analyzed for the induction of osteoclastogenesis or any effect on osteogenesis and signaling pathways. The results demonstrated that Ti particles could induce activation of the NFκB signaling pathway and induction of COX-2 and inflammatory cytokines in FLSs. The amount of Rankl in the conditioned medium collected from Ti particle–stimulated FLSs (Ti CM) showed the ability to stimulate osteoclast formation. The Ti CM also suppressed the osteogenic initial and terminal differentiation markers for osteoprogenitors, such as alkaline phosphate activity, matrix mineralization, collagen synthesis, and expression levels of Osterix, Runx2, collagen 1α, and bone sialoprotein. Inhibition of the WNT and BMP signaling pathways was observed in osteoprogenitors after the treatment with the Ti CM. In the presence of the Ti CM, exogenous stimulation by WNT and BMP signaling pathways failed to stimulate osteogenic activity in osteoprogenitors. Induced expression of sclerostin (SOST: an antagonist of WNT and BMP signaling) in Ti particle–treated FLSs and secretion of SOST in the Ti CM were detected. Neutralization of SOST in the Ti CM partially restored the suppressed WNT and BMP signaling activity as well as the osteogenic activity in osteoprogenitors. Our results reveal that wear debris–stimulated FLSs might affect bone loss by not only stimulating osteoclastogenesis but also suppressing the bone-forming ability of osteoprogenitors. In the clinical setting, targeting FLSs for the secretion of antagonists like SOST might be a novel therapeutic approach for preventing bone loss during inflammatory osteolysis.

Quinone-rich fraction of Ardisia crispa (Thunb.) A. DC roots alters angiogenic cascade in collagen-induced arthritis

Rheumatoid arthritis (RA) is a chronic joint disorder, of which, excessive angiogenesis is the well-established factor contributing to synovitis and joint destruction. Ardisia crispa (Primulaceae) is a medicinal herb with evidenced anti-angiogenic properties, attributed to 2-methoxy-6-undecyl-1,4-benzoquinone (BQ) found in its roots. However, it is still unclear how BQ is able to inhibit angiogenesis in RA. Hence, we investigated the anti-arthritic potential of quinone-rich fraction (QRF) separated from Ardisia crispa roots hexane extract (ACRH) by targeting angiogenesis on collagen-induced arthritis (CIA) in rats. The QRF was priorly identified by quantifying the BQ content in the fraction using GC-MS. Male Sprague-Dawley rats (n = 6) were initially immunised with type II collagen (150 µg) subcutaneously at the base of the tail on day 0. QRF (3, 10, and 30 mg/kg/day) and celecoxib (5 mg/kg/day) were orally administered for 13 consecutive days starting from day 14 post-induction, except for the vehicle and arthritic controls. QRF at all dosages moderately ameliorated the arthritic scores, ankle swelling, and hind paw oedema with no significant (p > 0.05) modulation on the bodyweights and organ weights (i.e., liver, kidney, and spleen). Treatment with QRF at 3, 10, and 30 mg/kg, significantly (p < 0.05) attenuated VEGF-A, PI3K, AKT, NF-κB, p38, STAT3, and STAT5 proteins and markedly restored the increased synovial microvessel densities (MVD) to the normal level in arthritic rats in a dose-independent manner. In conclusion, QRF conferred the anti-arthritic effect via angiogenesis inhibition in vivo, credited to the BQ content and synergism, at least in part, by other phytoconstituents.