Monocytes in rheumatoid arthritis: Circulating precursors of macrophages and osteoclasts and, their heterogeneity and plasticity role in RA pathogenesis

New insights on the protection of endangered aquatic species: Embryotoxicity effects of 2,2',4,4'-tetrabromodiphenyl ether (BDE-47) via integrin-mediated oxidative stress and inflammatory pathways in Siberian sturgeon, Acipenser baerii

Polybrominated diphenyl ethers (PBDEs), are emerging pollutants ubiquitous in the environment, posing a threat to aquatic ecosystems. This study investigates the toxicological effects of PBDEs on sturgeon embryos, focusing on BDE-47, a representative PBDEs homologues. Siberian sturgeon embryos were exposed to BDE-47, revealing significant reductions in hatching and survival rates and the occurrence of developmental abnormalities. Oxidative stress induction by BDE-47 was evidenced by increased antioxidant enzyme activities and the presence of oxidative damage biomarker MDA. Besides, transcriptome analysis unveiled the activation of integrin signaling pathways, with molecular docking indicating strong binding to integrin receptors (specifically ITG-α5, ITG-α8, and ITG-α11). Moreover, qPCR and correlation analysis showed that BDE-47 significantly upregulated inflammatory cytokines and keap1/nrf2 signaling through ITGs. Furthermore, cultivation of head kidney macrophages showed that ITGs antagonist Cilengitide significantly reversed the upregulation of the above factors induced by BDE-47, including nf-κb, il-6, tnf-α, gpx, and nrf2. These findings indicate that BDE-47 induced embryotoxicity in Siberian sturgeon, which was potentially via ITGs-mediated oxidative stress and inflammatory pathways. This study providing novel insights into the protein binding of BDE-47 in animals, contributes to understanding emerging pollutant toxicity in fish embryos and offering a new perspective for the improvement of hatchability and survival rate of cultured sturgeon embryos to guarantee the sustainable development of the sturgeon aquaculture industry, as well as providing evidence for wild sturgeon populations conservation and habitat restoration.

A novel inhibitory pathway of synovial inflammation exerted by glucocorticoids and tumour necrosis factor inhibitors via lymphocyte activation gene-3 up-regulation: an ex vivo study

OBJECTIVE

To investigate the impact of glucocorticoids (GCs) and anti-rheumatic drugs on lymphocyte activation gene-3 (LAG-3) and on programmed cell death-1 (PD-1) expression by synovial and peripheral cells ex vivo.

METHODS

Synovial fluid mononuclear cells (SFMCs) from psoriatic arthritis (PsA, n = 26) and rheumatoid arthritis (RA, n = 13) patients, synovial fluid cells (SFCs) from osteoarthritis (OA, n = 5) patients and peripheral blood mononuclear cells (PBMCs) of healthy donors (n = 14) were co-cultured with GCs, glucocorticoid receptor antagonist RU486, methotrexate (MTX) and biologics. LAG-3 and PD-1 expression on immune subsets were analysed by flow cytometry.

RESULTS

GCs in PsA inhibited SFMC growth vs medium [2.3 (0.4) × 105vs 5.3 (0.7) × 105, respectively, P < 0.01] and markedly up-regulated CD14+LAG-3+ cells [11.7 (2.4)% vs 0.8 (0.3)%, P < 0.0001, respectively], but not CD3+LAG-3+ and CD14+PD-1+ cells. MTX had no effect on CD14+LAG-3+ cells [0.7 (0.3)%]. The TNF inhibitors infliximab (IFX) and etanercept, but not IL-12/23 inhibitor, up-regulated CD14+LAG-3+ cells vs medium [2.0 (0.6)% and 1.6 (0.4)% vs 0.5 (0.1)%, P < 0.03, respectively]. SFMC growth inhibition by GC in both PsA and RA correlated with CD14+LAG-3+ cell up-regulation (r = 0.53, P = 0.03). RU486 inhibited GC-induced CD14+LAG-3+ cells up-regulation in a dose-dependent manner compared with GC alone [5 µM 5.3 (1.2)% and 50 µM 1.3 (0.5)% vs 7.0 (1.4)%, P < 0.003], but had no significant effect on CD14+LAG-3+ cells co-cultured with IFX. GCs in healthy donors' PBMCs up-regulated the immune subsets CD3+LAG-3+, CD14+LAG-3+ and CD14+PD-1+ cells.

CONCLUSION

This study proposes a novel regulatory mechanism of GCs and of TNF inhibitors mediated by LAG-3 up-regulation in synovial cells and PBMCs. LAG-3 modulation may be a promising target for development of novel therapies for inflammatory arthritis.

AI-Assisted Plasmonic Diagnostics Platform for Osteoarthritis and Rheumatoid Arthritis With Biomarker Quantification Using Mathematical Models

Osteoarthritis (OA) and rheumatoid arthritis (RA) are major causes of functional impairment, disability, and chronic pain, leading to a substantial rise in healthcare costs. Despite differences in pathophysiology, these diseases share overlapping features that complicate diagnosis, necessitating early, more accurate, and cost-effective diagnostic tools. This study introduces an innovative plasmonic diagnostics platform for rapid and accurate label-free diagnosis of OA and RA. The sensing platform utilizes a highly dense urchin-like gold nanoarchitecture (UGN), which enhances the surface plasmonic area to significantly amplify the Raman signal. The feasibility of the developed platform for arthritis diagnosis is demonstrated by analyzing the synovial fluid (SVF) of patients. Assisted by a machine learning model, Raman signals of OA and RA groups are successfully classified with high clinical sensitivity and specificity. Metabolic biomarkers are further investigated using mathematical models of combined Pearson correlation coefficient (PCC) and non-negative matrix factorization (NMF), suggesting valuable insights for arthritis biomarker quantification. In addition, RA severity is studied using the sensing platform by classifying results from the hematology test, achieving successful stage discrimination. This platform offers a versatile, affordable, and scalable in-clinic arthritis diagnostic solution with potential applications in diagnosing and monitoring other diseases through biofluid analysis.

Supplementation with N-Acetyl-L-cysteine during in vitro maturation improves goat oocyte developmental competence by regulating oxidative stress

Oocyte quality can affect mammal fertilization rate, early embryonic development, pregnancy maintenance, and fetal development. Oxidative stress induced by reactive oxygen species (ROS) is one of the most important causes of poor oocyte maturation in vitro. To reduce the degree of cellular damage caused by ROS, supplementation with the antioxidant N-Acetyl-L-cysteine (NAC) serves as an effective pathway to alleviate glutathione (GSH) depletion during oxidative stress. This study investigated the effects of NAC supplementation during in vitro maturation of goat oocytes and explored the molecular mechanisms of maturation by transcriptome sequencing of MⅡ oocytes. The results showed that 1.5 mM NAC significantly increased the rates of oocyte maturation and cumulus cell expansion and improved the subsequent development of embryos. During the subsequent culture of parthenogenetically activated embryos, 1.5 mM NAC significantly increased the division rate of oocytes and blastocyst rate. It also reduced the accumulation of ROS, increased the level of GSH, alleviated oxidative stress, and enhanced the antioxidant capacity and cell metabolic activity. Transcriptome sequencing results revealed that NAC treatment significantly increased the expression of SIRT1, GGCT, and MITF genes related to the cellular antioxidant system, as well as the IDH3G gene related to energy metabolism, and decreased the expression of CASP8, FOS, and MMP1 genes related to apoptosis and cell invasion, as well as the CCL2. and CXCL8 genes related to the inflammatory response. In conclusion, the findings suggest that NAC supplementation significantly reduces oxidative stress, improves antioxidant capacity and metabolic activity, promotes oocyte maturation, and improves oocyte quality.

FCGR1A(CD64) expression on monocyte subsets and FIL1Z(IL-37) serum level as biomarkers of rheumatoid arthritis activity: A case controlled study and in silico analysis

Rheumatoid arthritis (RA) is one of the most common chronic autoimmune diseases. Chronic joint inflammation and bone destruction were shown to be caused by expanded monocytes in RA affected individuals. Interleukin-37 which known as FIL1Z(IL-37) is a well-known anti-inflammatory cytokine that plays a negative regulatory role of inflammation in RA. A total of 48 RA patients were divided equally into active RA group and stable RA group using the Disease Activity score (DAS)-28 score. Twenty-four age-and sex-matched healthy subjects were enrolled as controls. The expression level of Fc gamma receptor IA (FCGR1A(CD64)) on monocytes and their subsets in peripheral blood were assessed by flow cytometry (FC) and serum levels of FIL1Z(IL-37) were measured by ELISA. The mean fluorescence intensity (MFI) of FCGR1A(CD64) expressing classical and intermediate monocyte subsets and serum levels of FIL1Z(IL-37) were significantly elevated in RA patients compared to the control and positively correlated with erythrocyte sedimentation rate (ESR), C-reactive protein (CRP), rheumatoid factor (RF), anti-cyclic citrullinated peptide (anti-CCP) and DAS-28 scores. The MFI of FCGR1A(CD64) expressing classical monocyte and serum levels of FIL1Z(IL-37) were significantly elevated in the active RA group compared to the stable RA group. The serum concentration of FIL1Z(IL-37) revealed very high specificity but limited sensitivity in discriminating between active and stable RA patients. Our results demonstrate a strong correlation between serum levels of FIL1Z(IL-37) and FCGR1A(CD64) expression on activated monocytes and their subsets in peripheral blood of RA patients. The results also depict that activated monocytes and their subsets may contribute to the elevated levels of FIL1Z(IL-37) during an active disease status to counter-act the inflammatory process.

The Impacts of Lactobacillus delbrueckii and Lactobacillus rhamnosus to Promote In Vitro Anti-Inflammatory Profile of RA-Macrophages

Rheumatoid arthritis (RA) is a prevalent and debilitating autoimmune disease. Numerous studies have demonstrated promising results regarding the use of probiotics as a therapeutic approach to alleviate RA symptoms. This study isolated monocytes from the PBMCs of RA patients and healthy donors. These monocytes were then differentiated into macrophages and divided into five groups: untreated, LPS-treated, L. delbrueckii (Del)-treated, L. rhamnosus (Ram)-treated, and a mixed treatment group. Three macrophage subpopulations-M0, M1, and M2-were identified in all treatment groups, with variations observed in the population percentages of each subpopulation and the expression levels of CD14, CD80, and HLA-DR. Flow cytometry results indicated that, compared to the untreated and LPS-treated groups, treatment with probiotic bacteria (Del, Ram, and Mix) stimulated the polarization of macrophages toward the M2 phenotype while suppressing the percentage of the M1 population. Additionally, the expression of CD14, a Pathogen-Associated Molecular Pattern (PAMP) and phagocytosis-inducing receptor, was significantly reduced in the probiotic-treated groups. Probiotic treatment also profoundly influenced antigen presentation by suppressing CD80, a ligand for the CD28 co-stimulatory marker on T cells, and HLA-DR, which presents antigens to the T cell receptors of Th4 cells. Interestingly, quantitative real-time PCR results indicated that probiotic treatment of macrophages significantly increased the expression of IL-10 and TGF-β, both anti-inflammatory cytokines, while significantly decreasing the expression of inflammatory cytokines, including IL-12, IL-1β, and TNF-α, in both healthy controls and RA patients. It seems that these probiotics may have a regulatory effect on macrophages, affecting their polarization, antigen presentation patterns, phagocytosis, and cytokine secretion profiles. This suggests that these probiotics may have therapeutic and prophylactic effects on RA.

Targeting BRD4 to attenuate RANKL-induced osteoclast activation and bone erosion in rheumatoid arthritis

Rheumatoid arthritis (RA) is a chronic autoimmune disease that can cause destruction of cartilage and bone's extracellular matrix. Bromodomain 4 (BRD4), as a transcriptional and epigenetic regulator, plays a key role in cancer and inflammatory diseases. While, the role of BRD4 in bone destruction in RA has not been extensively reported. Our study aimed to investigate the effect of BRD4 on the bone destruction in RA and, further, its mechanism in the pathogenesis of the disease. In this study, receiving approval from the Ethical Committee of the Affiliated Hospital of Qingdao University, we evaluated synovial tissues from patients with RA and OA for BRD4 expression through advanced techniques such as immunohistochemistry, quantitative real-time PCR (qRT-PCR), and Western blotting. We employed a collagen-induced arthritis (CIA) mouse model to assess the therapeutic efficacy of the BRD4 inhibitor JQ1 on disease progression and bone destruction, supported by detailed clinical scoring and histological examinations. Further, in vitro osteoclastogenesis assays using RAW264.7 macrophages, facilitated by TRAP staining and resorption pit assays, provided insights into the mechanistic effects of JQ1 on osteoclast function. Statistical analysis was rigorously conducted using SPSS, applying Kruskal-Wallis, one-way ANOVA, and Student's t-tests to validate the data. In our study, we found that BRD4 expression significantly increased in the synovial tissues of RA patients and the ankle joints of CIA mice, with JQ1, a BRD4 inhibitor, effectively reducing inflammation, arthritis severity (p < 0.05), and bone erosion. Treatment with JQ1 not only improved bone mass and structural integrity in CIA mice but also downregulated osteoclast-related gene expression and the RANKL/RANK signaling pathway, indicating a suppression of osteolysis. Furthermore, in vitro assays demonstrated that JQ1 markedly inhibited osteoclast differentiation and function, underscoring the pivotal role of BRD4 in osteoclastogenesis and its potential as a target for therapeutic intervention in RA-induced bone destruction. Our study concludes that targeting BRD4 with the inhibitor JQ1 significantly mitigates inflammation and bone destruction in rheumatoid arthritis, suggesting that inhibition of BRD4 may be a potential therapeutic strategy for the treatment of bone destruction in RA.

Monocyte-related markers as predictors of immune checkpoint inhibitor efficacy and immune-related adverse events: a systematic review and meta-analysis

The efficacy and off-target effects of immune checkpoint inhibitors (ICI) in cancer treatment vary among patients. Monocytes likely contribute to this heterogeneous response due to their crucial role in immune homeostasis. We conducted a systematic review and meta-analysis to evaluate the impact of monocytes on ICI efficacy and immune-related adverse events (irAEs) in patients with cancer. We systematically searched PubMed, Web of Science, and Embase for clinical studies from January 2000 to December 2023. Articles were included if they mentioned cancer, ICI, monocytes, or any monocyte-related terminology. Animal studies and studies where ICIs were combined with other biologics were excluded, except for studies where two ICIs were used. This systematic review was registered with PROSPERO (CRD42023396297) prior to data extraction and analysis. Monocyte-related markers, such as absolute monocyte count (AMC), monocyte/lymphocyte ratio (MLR), specific monocyte subpopulations, and m-MDSCs were assessed in relation to ICI efficacy and safety. Bayesian meta-analysis was conducted for AMC and MLR. The risk of bias assessment was done using the Cochrane-ROBINS-I tool. Out of 5787 studies identified in our search, 155 eligible studies report peripheral blood monocyte-related markers as predictors of response to ICI, and 32 of these studies describe irAEs. Overall, based on 63 studies, a high MLR was a prognostic biomarker for short progression-free survival (PFS) and overall survival (OS) hazard ratio (HR): 1.5 (95% CI: 1.21-1.88) and 1.52 (95% CI:1.13-2.08), respectively. The increased percentage of classical monocytes was an unfavorable predictor of survival, while low baseline rates of monocytic myeloid-derived suppressor cells (m-MDSCs) were favorable. Elevated intermediate monocyte frequencies were associated but not significantly correlated with the development of irAEs. Baseline monocyte phenotyping may serve as a composite biomarker of response to ICI; however, more data is needed regarding irAEs. Monocyte-related variables may aid in risk assessment and treatment decision strategies for patients receiving ICI in terms of both efficacy and safety.

Exploring the Role of Macrophages and Their Associated Structures in Rheumatoid Arthritis

BACKGROUND

Rheumatoid arthritis (RA) is a chronic, invasive autoimmune disease characterized by symmetrical polyarthritis involving synovial inflammation. Epidemiological studies indicate that the incidence of RA continues to rise, yet the pathogenesis of this disease remains not fully understood. A significant infiltration of macrophages is observed in the synovium of RA patients. It can be inferred that macrophages likely play a crucial role in the onset and progression of RA.

SUMMARY

This review aims to summarize the research progress on the mechanisms by which macrophages and their associated structures contribute to RA, as well as potential therapeutic approaches, aiming to provide new insights into the study of RA pathogenesis and its clinical treatment.

KEY MESSAGES

During the course of RA, besides the inherent roles of macrophages, these cells respond to microenvironmental changes such as pathogen invasion or tissue damage by undergoing polarization, pyroptosis, or forming macrophage extracellular traps (METs), all of which influence inflammatory responses and immune homeostasis, thereby mediating the occurrence and development of RA. Additionally, macrophages secrete exosomes, which participate in intercellular communication and signal transduction processes, thus contributing to the progression of RA. Therefore, it is critical to elucidate how macrophages and their related structures function in RA.

BACKGROUND

Rheumatoid arthritis (RA) is a chronic, invasive autoimmune disease characterized by symmetrical polyarthritis involving synovial inflammation. Epidemiological studies indicate that the incidence of RA continues to rise, yet the pathogenesis of this disease remains not fully understood. A significant infiltration of macrophages is observed in the synovium of RA patients. It can be inferred that macrophages likely play a crucial role in the onset and progression of RA.

SUMMARY

This review aims to summarize the research progress on the mechanisms by which macrophages and their associated structures contribute to RA, as well as potential therapeutic approaches, aiming to provide new insights into the study of RA pathogenesis and its clinical treatment.

KEY MESSAGES

During the course of RA, besides the inherent roles of macrophages, these cells respond to microenvironmental changes such as pathogen invasion or tissue damage by undergoing polarization, pyroptosis, or forming macrophage extracellular traps (METs), all of which influence inflammatory responses and immune homeostasis, thereby mediating the occurrence and development of RA. Additionally, macrophages secrete exosomes, which participate in intercellular communication and signal transduction processes, thus contributing to the progression of RA. Therefore, it is critical to elucidate how macrophages and their related structures function in RA.

Bidirectional Mendelian randomization reveals causal immune cell phenotypes in rheumatoid arthritis

Rheumatoid arthritis (RA) is a chronic autoimmune disease characterized by persistent inflammation in synovial joints and influenced by genetic and environmental factors. The immune system, comprising various cells that either exacerbate or reduce inflammation, plays a central role in RA pathogenesis. Despite extensive research, the causal relationships between immune cell phenotypes and RA remain unclear. We employed a two-sample Mendelian randomization (MR) approach to investigate the causal associations between 731 immune cell phenotypes and RA. Genetic variants, carefully selected based on rigorous criteria, served as instrumental variables to ensure analytical validity. Data on RA were derived from the FinnGen database, whereas immune cell phenotype data were obtained from the genome-wide association studies catalog. We employed 5 MR methods, including inverse variance weighted and MR Egger, to ensure robust causal inference. We assessed for pleiotropy and heterogeneity and adjusted findings using the False Discovery Rate. After False Discovery Rate adjustment (threshold < 0.05), inverse variance weighted analysis revealed potential causal relationships between 4 immune cell types and RA: CD62L- dendritic cells %dendritic cells (P = 3.88E-05; 95% confidence interval [CI] = 1.056), CD19 on IgD+ CD38- naive cells (P = 1.75E-04; 95% CI = 0.969), CD45RA on TD CD8br (P = 5.59E-04; 95% CI = 0.919), and HLA DR on CD33- HLA DR+ (P = 8.13E-05; 95% CI = 1.422). In reverse Mendelian studies, specific immune cell phenotypes were found to be associated with RA risk and progression: the percentage of memory B cells among lymphocytes (P = 2.74E-04; 95% CI = 0.861), IgD+ CD24+ cells among lymphocytes (P = 6.93E-04; 95% CI = 0.867), CD4+ CD8dim cells among lymphocytes (P = 2.92E-04; 95% CI = 0.802), CD4+ CD8dim cells among leukocytes (P = 4.37E-04; 95% CI = 0.814), and CD24 expression on IgD+CD24+ cells (P = 1.05E-04; 95% CI = 0.857). These results identify immune cell phenotypes closely linked to RA susceptibility and progression. The findings suggest that specific immune cell phenotypes are not only influenced by RA but may also contribute to its development and progression. These results offer new insights into the immunological underpinnings of RA and highlight potential targets for therapeutic intervention. Future research should focus on validating these causal relationships in diverse populations and exploring the molecular mechanisms involved.

Transcriptome signature in the blood of neuromyelitis optica spectrum disorder under steroid tapering

Background

The advent of biologics has significantly transformed treatment strategies for neuromyelitis optica spectrum disorder (NMOSD). However, there are no biomarkers that predict relapses associated with steroid tapering; therefore, it is critical to identify potential indicators of disease activity. In this study, we collected peripheral blood mononuclear cells (PBMCs) from NMOSD patients during steroid tapering and performed bulk RNA sequencing to analyze changes in immune dynamics caused by steroid reduction.

Methods

PBMCs were collected at 3-5 timepoints from 10 NMOSD patients at our hospital (including one relapse case), and bulk RNA sequencing was performed. All patients were positive for anti-AQP4 antibodies and had no history of biologic use.

Results

In one relapsed patient, gene groups with decreased expression at relapse were observed predominantly in monocytes, with upregulation in anti-inflammatory pathways such as IL-10, while the upregulated genes were related to interferon signaling. Moreover, after steroid tapering, in non-relapsed patients, genes with increased expression were enriched in inflammatory pathways, represented by interferon signaling, while genes with decreased expression were enriched in pathways related to IL-10 and glucocorticoid receptors. Weighted gene co-expression network analysis identified modules that correlated with steroid dosage, and the modules inversely correlated with steroid dosage were enriched in monocytes, with marked immune signature of interferon pathway.

Conclusion

This study identified peripheral blood transcriptome signatures that could lead to the identification of clinically relevant NMOSD disease activity biomarkers, and further highlights the pivotal role of interferon and IL-10 signaling in NMOSD.

NADPH oxidase expression profile and PBMC immunophenotypic changes in anti-TNF-treated rheumatoid arthritis patients

The aim of this research was to prospectively evaluate the impact of NOX2 gene expression profile (including NCF1, NCF2 and NCF4 genes) in peripheral blood mononuclear cells (PBMCs) on immune signatures, clinical characteristics and responsiveness to anti-TNF treatment in RA patients. Blood specimens were collected from 31 rheumatoid arthritis (RA) patients and 25 healthy controls, and 16 RA patients were followed at two timepoints during anti-TNF treatment. mRNA expression levels of selected genes and immunoregulatory cytokines concentrations were determined. We observed the significant upregulation of NCF4 and CD14 expression in RA group. The mRNA levels of NCF1 and CD14 positively correlated both in groups of RA patients and healthy controls. NOX2 gene expression profile was not associated with anti-TNF responsiveness, nor with RA clinical features. TNFα inhibition has not influenced NOX2 expression either. Notably, this study indicate the novel links between expression levels of NCF1 and monocyte differentiation antigen CD14.

Celastrol Regulates the Hsp90-NLRP3 Interaction to Alleviate Rheumatoid Arthritis

Previous studies have verified that celastrol (Cel) protects against rheumatoid arthritis (RA) by inhibiting the NLRP3 inflammasome signaling pathway, but the molecular mechanism by which Cel regulates NLRP3 has not been clarified. This study explored the specific mechanisms of Cel in vitro and in vivo. A type II collagen-induced arthritis (CIA) mouse model was used to study the antiarthritic activity of Cel; analysis of paw swelling, determination of the arthritis score, and pathological examinations were performed. The antiproliferative and antimigratory effects of Cel on TNF-α induced fibroblast-like synoviocytes (FLSs) were tested. Proinflammatory factors were evaluated using enzyme-linked immunosorbent assay (ELISA). The expression of NF-κB/NLRP3 pathway components was determined by western blotting and immunofluorescence staining in vitro and in vivo. The putative binding sites between Cel and Hsp90 were predicted through molecular docking, and the binding interactions were determined using the Octet RED96 system and coimmunoprecipitation. Cel decreased arthritis severity and reduced TNF-α-induced FLSs migration and proliferation. Additionally, Cel inhibited NF-κB/NLRP3 signaling pathway activation, reactive oxygen species (ROS) production, and proinflammatory cytokine secretion. Furthermore, Cel interacted directly with Hsp90 and blocked the interaction between Hsp90 and NLRP3 in FLSs. Our findings revealed that Cel regulates NLRP3 inflammasome signaling pathways both in vivo and in vitro. These effects are induced through FLSs inhibition of the proliferation and migration by blocking the interaction between Hsp90 and NLRP3.

Deep-insights: Nanoengineered gel-based localized drug delivery for arthritis management

Arthritis is an inflammatory joint disorder that progressively impairs function and diminishes quality of life. Conventional therapies often prove ineffective, as oral administration lacks specificity, resulting in off-target side effects like hepatotoxicity and GIT-related issues. Intravenous administration causes systemic side effects. The characteristic joint-localized symptoms such as pain, stiffness, and inflammation make the localized drug delivery suitable for managing arthritis. Topical/transdermal/intra-articular routes have become viable options for drug delivery in treating arthritis. However, challenges with those localized drug delivery routes include skin barrier and cartilage impermeability. Additionally, conventional intra-articular drug delivery also leads to rapid clearance of drugs from the synovial joint tissue. To circumvent these limitations, researchers have developed nanocarriers that enhance drug permeability through skin and cartilage, influencing localized action. Gel-based nanoengineered therapy employs a gel matrix to incorporate the drug-encapsulated nanocarriers. This approach combines the benefits of gels and nanocarriers to enhance therapeutic effects and improve patient compliance. This review emphasizes deep insights into drug delivery using diverse gel-based novel nanocarriers, exploring their various applications embedded in hyaluronic acid (biopolymer)-based gels, carbopol-based gels, and others. Furthermore, this review discusses the influence of nanocarrier pharmacokinetics on the localization and therapeutic manipulation of macrophages mediated by nanocarriers. The ELVIS (extravasation through leaky vasculature and inflammatory cell-mediated sequestration) effect associated with arthritis is advantageous in drug delivery. Simply put, the ELVIS effect refers to the extravasation of nanocarriers through leaky vasculatures, which finally results in the accumulation of nanocarriers in the joint cavity.

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.

Immune pathogenic response landscape of acute posterior multifocal placoid pigment epitheliopathy revealed by scRNA sequencing

Acute posterior multifocal placoid pigment epitheliopathy (APMPPE) is an exceptionally rare inflammatory disorder affecting choroid and retinal pigment epithelial (RPE) cells. Although recent studies suggest an immune-driven nature, the underlying etiology of APMPPE remains elusive. In this study, we conducted a comprehensive investigation on the peripheral blood mononuclear cells (PBMCs) profile of an APMPPE patient using single-cell RNA sequencing. Our analysis revealed striking transcriptional alterations in monocytes within the PBMCs, identifying five distinct subpopulations: S100A12, CD16, pro-inflammatory, megakaryocyte-like, and NK-like monocyte subsets. Employing pseudotime inference, we observed a shift in APMPPE monocytes towards differentiation into inflammation-associated pro-inflammatory monocytes and a CD16 monocyte trajectory. Furthermore, we identified IFITM3 as a key player in the immune response driving the pathogenesis of APMPPE. Notably, two disease-relevant subgroups of monocytes, pro-inflammatory and CD16 monocytes, were implicated in APMPPE. CD16 monocytes, in particular, were involved in melanogenesis, suggesting that the abnormal expression of melanin in monocytes might result from autoimmune responses against pigment-enriched RPE cells. This study provided a comprehensive view of immune landscape in APMPPE, shedding light on the previously unrecognized contributions of pro-inflammatory and CD16 monocytes to this autoimmune condition.

Circulating Baseline CXCR3+Th2 and Th17 Cell Proportions Correlate With Trabecular Bone Loss After 48 Weeks of Biological Treatment in Early Rheumatoid Arthritis

OBJECTIVE

The high prevalence of osteoporosis in rheumatoid arthritis (RA) is due to inflammation that stimulates differentiation of osteoclasts, a process involving circulating monocytes and T cell-derived factors. The aim of this study was to evaluate relations between circulating monocytes, T cell subsets, and changes in bone characteristics before and after treatment with biological disease-modifying antirheumatic drugs (bDMARDs) in RA.

METHODS

Thirty patients with untreated early RA who met the American College of Rheumatology/EULAR 2010 criteria were included. Data were collected before and 48 weeks after treatment with methotrexate (MTX) together with one of three bDMARDs (abatacept, tocilizumab, or certolizumab pegol). Disease activity was measured using the Clinical Disease Activity Index, swollen or tender joint counts, C-reactive protein levels, and erythrocyte sedimentation rates. Proportions of monocyte and CD4+ T cell subsets in blood samples were analyzed by flow cytometry. Bone densitometry was performed using high-resolution peripheral quantitative computed tomography (HR-pQCT).

RESULTS

HR-pQCT revealed an overall decrease in cortical (P = 0.009) and trabecular (P = 0.034) bone mineral density, although a subset of patients showed no bone loss after 48 weeks of treatment. The overall bone loss was not associated with age, body mass index, sex, intraarticular glucocorticoid injections, or baseline disease activity. Loss of trabecular bone volume fraction correlated with high proportions of circulating CXCR3+Th2 cells (r = -0.38, P = 0.04) and CXCR3+Th17 cells (r = -0.36, P = 0.05) at baseline. Similarly, no loss of trabecular bone volume fraction correlated with high proportions of regulatory T cells (r = 0.4, P = 0.03) at baseline. However, the associations were not significant when corrected for confounders and multiple testing.

CONCLUSION

MTX together with bDMARDs efficiently reduce disease activity but only prevent bone loss in a subset of patients with RA after 48 weeks of treatment. The correlations of circulating baseline T helper cell and regulatory T cell populations with trabecular bone changes suggest a potential novel role for these cells in systemic bone homeostasis during early RA.

Proteomics analysis of body fluid exosomes of rheumatoid arthritis patients underwent oxhorn cupping therapy

OBJECTIVE

The present study was undertaken to understand the multitarget mechanisms of oxhorn cupping therapy (OHCT) in treating rheumatoid arthritis by proteomic analysis.

METHODS

Thirty rheumatoid arthritis patients underwent OHCT and liquid (body fluid) accumulated in the cupping vessels was collected. Exosomes from the body fluid were isolated and characterized by transmission electron microscope (TEM). Particle size analysis, fluorescent labeling, and flow cytometry detection were also performed. Label-free quantitative proteomics analysis was used to detect differentially expressed proteins (DEPs). The Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway enrichment, gene ontology (GO) enrichment, clusters of orthologous groups (COG), and protein-protein interaction (PPI) network were used to perform bioinformatics analysis of DEPs. Enzyme-linked immunosorbent assay (ELISA) was used to detect the key targets regulated by OHCT.

RESULTS

According to TEM images, the average size of exosomes in body fluid of RA patients underwent OHCT was 76.13 nm (5.27E+10 /mL). The positive rates of CD9, CD63, and CD8 were detected on the surface of body fluid exosomes. A total of 300 DEPs (58 up-regulated and 242 down-regulated) were identified between the pre-treatment and post-treatment stages. DEPs were related mostly to protein binding, focal adhesion, extracellular region, post-translational modification and signal transduction. KEGG pathway analysis showed a significant enrichment of DEPs in PI3K-Akt pathway and focal adhesion. Ten DEGs (ITGA5, ITGA4, ENG, MMP14, SERPINH1, THY1, TAGLN, ITGA1, IGF1, and ITGB5) were considered target genes according to PPI network analysis. ELISA showed a slight decrease in the serum levels of CDK1, ITGA5, ITGB5, and CD44 during and after treatment.

CONCLUSIONS

Body fluid samples from RA patients treated with oxhorn cupping contain exosomes. OHCT might exert therapeutic effects in RA through multiple signaling pathways and multiple protein targets.

Role of Circulating Monocytes and Periodontopathic Bacteria in Pathophysiology of Rheumatoid Arthritis

Rheumatoid arthritis (RA) is characterized by chronic inflammation in the synovial membrane, leading to matrix destruction of cartilage and bone. While various types of immune cell are found in inflamed synovium in RA, macrophages and osteoclasts also play important roles in joint destruction. Peripheral blood monocytes migrate to synovial tissue and differentiate into macrophages and osteoclasts in RA. Synovial macrophages are classified into two subsets: M1 (proinflammatory macrophages) or M2 (anti-proinflammatory macrophages). Human circulating monocytes have also been divided into three subsets according expression level of CD14 and CD16: CD14+CD16- (classical); CD14brightCD16+ (intermediate); or CD14dimCD16+ (non-classical). Many recent studies have investigated the involvement of each subset of synovial macrophages and circulating monocytes in the pathophysiology of RA. On the other hand, several distinct human cell populations originating in circulating monocytes have the capacity to differentiate into non-phagocytic cells, including endothelial cells and adipocytes. This review summarizes the role of circulating monocytes in the pathophysiology of RA as precursor cells of not only phagocytes, such as macrophages and osteoclasts, but also non-phagocytes, such as endothelial cells and adipocytes. Furthermore, there is a growing body of evidence showing a significantly positive association between periodontopathic bacterial infection and the pathophysiology of RA. Therefore, the role of periodontopathic bacteria in the development of RA is also discussed.

Emerging influence of RNA post-transcriptional modifications in the synovial homeostasis of rheumatoid arthritis

Rheumatoid arthritis (RA) is an important autoimmune disease that affects synovial tissues, accompanied by redness, pain, and swelling as main symptoms, which will limit the quality of daily life and even cause disability. Multiple coupling effects among the various cells in the synovial micro-environment modulate the poor progression and development of diseases. Respectively, synovium is the primary target tissue of inflammatory articular pathologies; synovial hyperplasia, and excessive accumulation of immune cells lead to joint remodelling and destroyed function. In general, epigenetic modification is an effective strategy to regulate dynamic balance of synovial homeostasis. Several typical post-transcriptional changes in cellular RNA can control the post-transcriptional modification of RNA structure. It can inhibit important processes, including degradation of RNA and nuclear translocation. Recent studies have found that RNA modification regulates the homeostasis of the synovial micro-environment and forms an intricate network in the "bone-cartilage-synovium" feedback loop. Aberrant regulation of RNA methylation triggers the pathological development of RA. Collectively, this review summarises recent advanced research about RNA modification in modulating synovial homeostasis by making close interaction among resident synovial macrophages, fibroblasts, T cells, and B cells, which could display the dramatic role of RNA modifications in RA pathophysiological process and perform the promising therapeutic target for treating RA.

The role of macrophage polarization in rheumatoid arthritis and osteoarthritis: Pathogenesis and therapeutic strategies

Rheumatoid arthritis (RA) and osteoarthritis (OA) are common and debilitating joint disorders affecting millions of individuals worldwide. Despite their distinct pathological features, both conditions share a crucial role of macrophages in disease progression. Macrophages exhibit remarkable plasticity, polarizing into pro-inflammatory M1 or anti-inflammatory M2 phenotypes in response to environmental cues. An imbalance in macrophage polarization, particularly a shift towards the M1 phenotype, contributes to chronic inflammation and joint damage in RA and OA. This review explores the complex interplay between macrophages and various cell types, including T cells, B cells, synovial fibroblasts, osteoclasts, chondrocytes, and adipocytes, in the pathogenesis of these diseases. We discuss the current understanding of macrophage polarization in RA and OA, highlighting the molecular mechanisms involved. Furthermore, we provide an overview of potential therapeutic strategies targeting macrophage polarization, such as disease-modifying anti-rheumatic drugs, traditional Chinese medicine, nanomedicines, proteins, chemical compounds, and physical therapies. By elucidating the precise mechanisms governing macrophage polarization and its interactions with other cells in the joint microenvironment, researchers can identify novel therapeutic targets and develop targeted interventions to alleviate disease progression and improve patient outcomes in RA and OA.

Proteomic Profile Regulated by the Immunomodulatory Jusvinza Drug in Neutrophils Isolated from Rheumatoid Arthritis Patients

Jusvinza is an immunomodulatory drug composed of an altered peptide ligand (APL) designed from a novel CD4+ T cell epitope of human heat shock protein 60 (HSP60), an autoantigen involved in the pathogenesis of rheumatoid arthritis (RA). The peptide induces regulatory T cells and decreases levels of TNF-α and IL-17; pre-clinical and phase I clinical studies support its use for the treatment of RA. This peptide was repositioned for the treatment of COVID-19 patients with signs of hyperinflammation. Neutrophils play a pathogenic role in both RA and severe forms of COVID-19. To add novel evidence about the mechanism of action of Jusvinza, the proteomic profile regulated by this peptide of neutrophils isolated from four RA patients was investigated using LC-MS/MS and bioinformatics analysis. A total of 149 proteins were found to be differentially modulated in neutrophils treated with Jusvinza. The proteomic profile regulated by Jusvinza is characterized by the presence of proteins related to RNA splicing, phagocytosis, endocytosis, and immune functions. In response to Jusvinza treatment, several proteins that regulate the NF-κB signaling pathway were differentially modulated, supporting the peptide's anti-inflammatory effect. Proteins related to metabolic pathways that supply ATP for cellular functions or lipid metabolites with immunoregulatory properties were also identified. Additionally, several structural components of neutrophil extracellular traps (NETs) were decreased in Jusvinza-treated cells, supporting its impairment of this biological process. Of note, these findings were validated by in vitro experiments which confirmed that Jusvinza decreased NET formation. Such results provide evidence of the molecular mechanism of action and support the therapeutic potentialities of Jusvinza to treat other diseases characterized by hyperinflammation besides RA and COVID-19.

Ganlu formula ethyl acetate extract (GLEE) blocked the development of experimental arthritis by inhibiting NLRP3 activation and reducing M1 type macrophage polarization

ETHNOPHARMACOLOGICAL RELEVANCE

The Tibetan medicine Ganlu Formula, as a classic prescription, is widely used across the Qinghai-Tibet Plateau area of China, which has a significant effect on relieving the course of rheumatoid arthritis (RA). However, the active compounds and underlying mechanisms of Ganlu Formula in RA treatment remain largely unexplored.

AIM OF THE STUDY

This study aimed to elucidate the active substances and potential mechanisms of the ethyl acetate extract of Ganlu Formula ethyl acetate extract (GLEE) in the treatment of RA.

MATERIALS AND METHODS

Ultra-performance liquid chromatography coupled with quadrupole time-of-flight mass spectrometry (UPLC-Q-TOF-MS) was utilized to analyze and identify the chemical constituents within GLEE. Discovery Studio molecular virtual docking technology was utilized to dock the interaction of GLEE with inflammation-related pathway proteins. The GLEE gene library was obtained by transcriptome sequencing. Collagen-induced arthritic（CIA) rats were utilized to assess the antiarthritic efficacy of GLEE. Micro-CT imaging was employed to visualize the rat paw, and ultrasound imaging revealed knee joint effusion. Evaluation of synovial tissue pathological changes was conducted through hematoxylin-eosin staining and saffranine solid green staining, while immunohistochemical staining was employed to assess NLRP3 expression along with inflammatory markers. Immunofluorescence staining was utilized to identify M1 macrophages.

RESULTS

Metabolomic analysis via UPLC-Q-TOF-MS identified 28 potentially bioactive compounds in GLEE, which interacted with the active sites of key proteins such as NLRP3, NF-κB, and STAT3 through hydrogen bonds, C-H bonds, and electrostatic attractions. In vitro analyses demonstrated that GLEE significantly attenuated NLRP3 inflammasome activation and inhibited the polarization of bone marrow-derived macrophages (BMDMs) towards the M1 phenotype. In vivo, GLEE not only prevented bone mineral density (BMD) loss but also reduced ankle swelling in CIA rats. Furthermore, it decreased the expression of the NLRP3 inflammasome and curtailed the release of inflammatory mediators within the knee joint.

CONCLUSION

GLEE effectively mitigated inflammatory responses in both blood and knee synovial membranes of CIA rats, potentially through the down-regulation of the NLRP3/Caspase-1/IL-1β signaling pathway and reduction in M1 macrophage polarization.

Identification of the ferroptosis-related gene signature and the associated regulation axis in lung cancer and rheumatoid arthritis

Patients with Rheumatoid arthritis (RA) have an elevated risk of lung cancer compared to the healthy population. However, there are few studies on the relationship between RA and lung adenocarcinoma (LUAD), especially the mechanisms at the genetic level. In this study, we investigated the link between RA and LUAD regarding Ferroptosis-Related Genes. The RNA-seq data of RA (GSE77298 and GSE 82107) and LUAD(GSE75037) in the Gene Expression Omnibus (GEO) database were obtained. 259 ferroptosis-related genes were obtained from the website ( http://www.zhounan.org/ferrdb/ ).The differential genes obtained from the RA and LUAD datasets were intersected with ferroptosis-related genes to obtain the ferroptosis-related differentially expressed genes (FRDEGs). Next, the mRNA-miRNA network was constructed, then Gene Set Enrichment Analysis (GSEA) for target genes were performed. The CIBERSORT algorithm was used to analyze the immune infiltration. Finally, the results were validated using external datasets (GSE89408 and GSE48780) and The Cancer Genome Atlas (TCGA) dataset. We obtained FRDEGs common to LUAD and RA: FANCD2, HELLS, RRM2, G6PD, VLDLR. These five genes play important roles in the progression of RA and LUAD. They also hold great diagnostic value for both diseases. Also, we found that LUAD and RA share common signaling pathways and similar immune mechanisms.

Dietary omega-3 fatty acids modulate the production of platelet-derived microvesicles in an in vivo inflammatory arthritis model

PURPOSE

The aim of this study was to investigate the effects of different ω-3 polyunsaturated fatty acid (PUFA) enriched diets, including a novel renewable plant source of ω-3 fatty acids (Buglossoides arvensis), on the development and progression of rheumatoid arthritis (RA).

METHODS

RA was induced in mice consuming experimental diets using the K/BxN model. The experimental diets consisted of either a western control diet (control), diets containing B. arvensis oil or fish oil. The effects of the diets on platelets, platelet microvesicles (PMVs), and inflammatory markers such as clinical index, ankle thickness and cytokine/chemokine release were measured.

RESULTS

While ω-3 PUFA-enriched diets did not prevent the development of arthritis in the K/BxN model, a significant decrease in ankle swelling was observed compared to the control group. Platelets isolated from mice consuming either low content of B. arvensis oil or fish oil diets exhibited significantly decreased PMVs production compared to mice consuming the control diet.

CONCLUSION

Our study provides insight into the contribution of ω-3 PUFA supplementation in modulating the pro-inflammatory phenotype of platelets in RA pathology. Furthermore, our study suggests that low concentrations of dietary B. arvensis oil may have similar anti-inflammatory potential seen with dietary fish oil supplementation.

The role of macrophages in fibrosis of chronic kidney disease

Macrophages are widely distributed throughout various tissues of the body, and mounting evidence suggests their involvement in regulating the tissue microenvironment, thereby influencing disease onset and progression through direct or indirect actions. In chronic kidney disease (CKD), disturbances in renal functional homeostasis lead to inflammatory cell infiltration, tubular expansion, glomerular atrophy, and subsequent renal fibrosis. Macrophages play a pivotal role in this pathological process. Therefore, understanding their role is imperative for investigating CKD progression, mitigating its advancement, and offering novel research perspectives for fibrosis treatment from an immunological standpoint. This review primarily delves into the intrinsic characteristics of macrophages, their origins, diverse subtypes, and their associations with renal fibrosis. Particular emphasis is placed on the transition between M1 and M2 phenotypes. In late-stage CKD, there is a shift from the M1 to the M2 phenotype, accompanied by an increased prevalence of M2 macrophages. This transition is governed by the activation of the TGF-β1/SMAD3 and JAK/STAT pathways, which facilitate macrophage-to-myofibroblast transition (MMT). The tyrosine kinase Src is involved in both signaling cascades. By thoroughly elucidating macrophage functions and comprehending the modes and molecular mechanisms of macrophage-fibroblast interaction in the kidney, novel, tailored therapeutic strategies for preventing or attenuating the progression of CKD can be developed.

High dimensional proteomic mapping of bone marrow immune characteristics in immune thrombocytopenia

To investigate the role of co-stimulatory and co-inhibitory molecules on immune tolerance in immune thrombocytopenia (ITP), this study mapped the immune cell heterogeneity in the bone marrow of ITP at the single-cell level using Cytometry by Time of Flight (CyTOF). Thirty-six patients with ITP and nine healthy volunteers were enrolled in the study. As soluble immunomodulatory molecules, more sCD25 and sGalectin-9 were detected in ITP patients. On the cell surface, co-stimulatory molecules like ICOS and HVEM were observed to be upregulated in mainly central memory and effector T cells. In contrast, co-inhibitory molecules such as CTLA-4 were significantly reduced in Th1 and Th17 cell subsets. Taking a platelet count of 30×109 L-1 as the cutoff value, ITP patients with high and low platelet counts showed different T cell immune profiles. Antigen-presenting cells such as monocytes and B cells may regulate the activation of T cells through CTLA-4/CD86 and HVEM/BTLA interactions, respectively, and participate in the pathogenesis of ITP. In conclusion, the proteomic and soluble molecular profiles brought insight into the interaction and modulation of immune cells in the bone marrow of ITP. They may offer novel targets to develop personalized immunotherapies.

Attenuation of adjuvant-induced arthritis with carnosic acid by inhibiting mPGES-1, COX-2, and bone loss in male SD rats

OBJECTIVE

Rheumatoid arthritis (RA), a chronic inflammatory disease, is characterized by joint swelling, cartilage erosion, and bone destruction. This study investigated the therapeutic efficacy of Carnosic acid (CA), a natural compound with anti-inflammatory and antioxidant properties, in an adjuvant-induced arthritis model.

METHODS

Paw swelling and arthritis index were measured. Oxidative stress markers, including lipid peroxidation and antioxidant enzyme levels, were assessed. Synovial tissue was analyzed for pro-inflammatory markers using real-time Q-PCR and Western blotting. The expression of mPGES-1 was determined by Western blotting. Peripheral neuropathic pain was assessed using cold and mechanical allodynia tests. Bone loss was quantitatively assessed through microcomputed tomography (μCT) scanning of femurs and X-ray radiography. Indomethacin-induced gastric ulcers were evaluated. Molecular docking studies were conducted to analyze the binding affinity of CA to mPGES-1.

RESULTS

The CA treatment not only demonstrated a significant reduction in joint inflammation and paw swelling but also mitigated oxidative stress and improved the antioxidant defence system. CA inhibited microsomal prostaglandin E synthase-1 (mPGES-1) expression and the expression of pro-inflammatory molecules such as inducible nitric oxide synthase (iNOS) and cyclooxygenases-2 (COX-2), thus attenuating the arthritis symptoms without severe gastrointestinal side effects. Additionally, it inhibited the expression of pro-inflammatory molecules such as iNOS and COX-2, contributing to the reduction of arthritis symptoms. Notably, CA treatment prevented the common side effects of traditional RA treatments like corticosteroids and non-steroidal anti-inflammatory drugs (NSAIDs), including weight loss, bone degradation, and gastric ulcers.

CONCLUSIONS

These findings suggest that CA, through specific enzyme inhibition, offers a compelling alternative therapeutic approach for RA. Further research is warranted to explore the potential of CA in other arthritis models and its suitability for human RA treatment.

CD14+ Dendritic-Shaped Cells Functioning as Dendritic Cells in Rheumatoid Arthritis Synovial Tissues

OBJECTIVE

We previously reported that CD14+ dendritic-shaped cells exhibit a dendritic morphology, engage in pseudo-emperipolesis with lymphocytes, and express CD90 in the perivascular areas of rheumatoid arthritis (RA) synovial tissues. However, it remains unclear whether these CD14highCD90intermediate(int) cells function as dendritic cells. In this study, we investigated the dendritic cell-differentiation potential of CD14highCD90int cells.

METHODS

The localization and number of CD14highCD90int cells in RA synovial tissues and peripheral blood were examined. The dendritic cell-differentiation potential of CD14highCD90int cells was examined by measuring interleukin-6 and tumor necrosis factor-α levels in the supernatant and CD83 and human leukocyte antigen (HLA)-DR expression in the cells after induction of dendritic cell differentiation. Synovial cells were co-cultured with lymphocytes, and the activation of these cells was examined.

RESULTS

CD14highCD90int cells were abundant in RA synovial tissues, including the sublining layer and the pannus areas. Patients with untreated and active RA had significantly higher percentages of CD14highCD90int cells in the peripheral blood and synovial tissues. In RA synovial cells, inflammatory cytokine levels increased with dendritic cell-differentiation culture, but CD83 and HLA-DR expression were significantly increased in the CD14highCD90int cell group. When co-cultured with lymphocytes, cell numbers and inflammatory cytokine levels significantly increased in both groups of synovial cells after dendritic cell induction.

CONCLUSION

CD14+ cells migrate and spread from the circulating blood to RA synovial tissues while expressing CD90, and CD14highCD90int cells in contact with lymphocytes differentiate into HLA-DR+ dendritic cells, which contribute to chronic inflammation in RA.

Fufang Duzheng tablet attenuates adjuvant rheumatoid arthritis by inhibiting arthritis inflammation and gut microbiota disturbance in rats

Objective

To explore the treatment effect and potential mechanism on gut microbiota, nutrition, and metabolism of Fufang Duzheng Tablet (DZGP) on rheumatoid arthritis (RA).

Methods

Collagen-induced arthritis rats' models were established and divided into three groups: model control group (FK), DZGP group (FZ, 0.45 g/kg/d), and methotrexate group (FM, 1.35 mg/kg), which were treated by gavage for 28 days. The physiopathologic changes of joints and body weight in each group were recorded; the morphology of synovial and ankle tissues was observed by hematoxylin-eosin staining, and the level of serum TNF-α and IL-1β was tested by ELISA. UPLC/MS-MS and network pharmacological analysis were used to identify the serum components, and 16S rDNA sequencing analysis was applied to the intestinal contents of rats.

Results

DZGP treatment significantly alleviated arthritis symptoms, pathological manifestations, toe thickness, and TNF-α and IL-1β levels in RA rats. We identified 105 metabolites and 18 components in the serum of DZGP-group rats. The main therapeutic targets of DZGP for anti-RA were TP53, epidermal growth factor receptor, and AKT1. Molecular docking showed that there was good binding efficiency between core components and main targets. 16S rDNA sequencing showed that DZGP treatment regulated the structure of the gut microbiota.

Conclusion

DZGP showed a good anti-inflammatory effect on RA and played an important role in improving the structure of the gut microbiota in RA rats.

Systemic inflammatory biomarkers are novel predictors of all-cause and cardiovascular mortality in individuals with osteoarthritis: a prospective cohort study using data from the NHANES

BACKGROUND

Chronic inflammation may contribute to increased mortality risk in individuals with osteoarthritis (OA), but research on the prognostic value of inflammatory biomarkers is limited. We aimed to evaluate the associations of the systemic immune-inflammation index (SII) and systemic inflammation response index (SIRI) with all-cause and cardiovascular mortality among US adults with OA.

METHODS

This cohort study included 3545 adults with OA aged ≥ 20 years from the National Health and Nutrition Examination Survey 1999-2020. The SII and SIRI were calculated using complete blood cell count data. Participants were categorized as having a higher or lower SII and SIRI using cutoff points derived by the maximally selected rank statistics method. Cox proportional hazards models, Fine-Gray competing risk regression models and time-dependent receiver operating characteristic (ROC) analysis were used to evaluate the associations between the SII/SIRI and mortality in OA patients.

RESULTS

Over a median follow-up of 5.08 (3.42-9.92) years, 636 (17.94%) deaths occurred, including 149 (4.20%) cardiovascular deaths. According to multivariable-adjusted models involving demographic, socioeconomic, and health factors, OA patients with a higher SII had a twofold greater risk of all-cause mortality than patients with a lower SII (HR 2.01; 95% CI: 1.50-2.68). Similarly, a higher SIRI was associated with an 86% increased risk of all-cause mortality relative to a lower SIRI (HR 1.86; 95% CI: 1.46-2.38). Similar to the trend found with all-cause mortality, patients with an elevated SII and SIRI had a 88% and 67% increased risk of cardiovascular mortality, respectively, compared to patients with a lower SII (HR 1.88; 95% CI: 1.16-3.03) and SIRI (HR 1.67; 95% CI: 1.14-2.44). Time-dependent ROC curves showed that both the SII and SIRI have moderate and valid performance in predicting short- and long-term mortality in patients with OA.

CONCLUSIONS

Higher SII and SIRI values were associated with greater all-cause and cardiovascular mortality among US adults with OA.

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

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

Disease activity drives divergent epigenetic and transcriptomic reprogramming of monocyte subpopulations in systemic lupus erythematosus

OBJECTIVES

Systemic lupus erythematosus (SLE) is characterised by systemic inflammation involving various immune cell types. Monocytes, pivotal in promoting and regulating inflammation in SLE, differentiate from classic monocytes into intermediate and non-classic monocytes, assuming diverse roles and changing their proportions in inflammation. In this study, we investigated the epigenetic and transcriptomic profiles of these and novel monocyte subsets in SLE in relation to activity and progression.

METHODS

We obtained the DNA methylomes and transcriptomes of classic, intermediate, non-classic monocytes in patients with SLE (at first and follow-up visits) and healthy donors. We integrated these data with single-cell transcriptomics of SLE and healthy donors and interrogated their relationships with activity and progression.

RESULTS

In addition to shared DNA methylation and transcriptomic alterations associated with a strong interferon signature, we identified monocyte subset-specific alterations, especially in DNA methylation, which reflect an impact of SLE on monocyte differentiation. SLE classic monocytes exhibited a proinflammatory profile and were primed for macrophage differentiation. SLE non-classic monocytes displayed a T cell differentiation-related phenotype, with Th17-regulating features. Changes in monocyte proportions, DNA methylation and expression occurred in relation to disease activity and involved the STAT pathway. Integration of bulk with single-cell RNA sequencing datasets revealed disease activity-dependent expansion of SLE-specific monocyte subsets, further supported the interferon signature for classic monocytes, and associated intermediate and non-classic populations with exacerbated complement activation.

CONCLUSIONS

Disease activity in SLE drives a subversion of the epigenome and transcriptome programme in monocyte differentiation, impacting the function of different subsets and allowing to generate predictive methods for activity and progression.

A Less-is-More Strategy for Mitochondria-Targeted Photodynamic Therapy of Rheumatoid Arthritis

Conventional photodynamic therapy (PDT) of rheumatoid arthritis (RA) faces a dilemma: low-power is insufficient to kill pro-inflammatory cells while high-power exacerbates inflammation. Herein, mitochondrial targeting is introduced in PDT of RA to implement a "less-is-more" strategy, where higher apoptosis in pro-inflammatory cells are achieved with lower laser power. In arthritic rats, chlorine 6-loaded and mitochondria-targeting liposomes (Ce6@M-Lip) passively accumulated in inflamed joints, entered pro-inflammatory macrophages, and actively localized to mitochondria, leading to enhanced mitochondrial dysfunction under laser irradiation. By effectively disrupting mitochondria, pro-inflammatory macrophages are more susceptible to PDT, resulting in increased apoptosis initiation. Additionally, it identifies that high-power irradiation caused cell rupture and release of endogenous danger signals that recruited and activated additional macrophages. In contrast, under low-power irradiation, mitochondria-targeting Ce6@M-Lip not only prevented inflammation but also reduced pro-inflammatory macrophage infiltration and pro-inflammatory cytokine secretion. Overall, targeting mitochondria reconciled therapeutic efficacy and inflammation, thus enabling efficacious yet inflammation-sparing PDT for RA. This highlights the promise of mitochondrial targeting to resolve the dilemma between anti-inflammatory efficacy and inflammatory exacerbation in PDT by implementing a "less-is-more" strategy.

A systematic review: Sinomenine

Sinomenine (SIN), an alkaloid derived from the traditional Chinese medicine, Caulis Sinomenii, has been used as an anti-inflammatory drug in China for over 30 years. With the continuous increase in research on the pharmacological mechanism of SIN, it has been found that, in addition to the typical rheumatoid arthritis (RA) treatment, SIN can be used as a potentially effective therapeutic drug for anti-tumour, anti-renal, and anti-nervous system diseases. By reviewing a large amount of literature and conducting a summary analysis of the literature pertaining to the pharmacological mechanism of SIN, we completed a review that focused on SIN, found that the current research is insufficient, and offered an outlook for future SIN development. We hope that this review will increase the public understanding of the pharmacological mechanisms of SIN, discover SIN research trial shortcomings, and promote the effective treatment of immune diseases, inflammation, and other related diseases.

Glycolysis, a driving force of rheumatoid arthritis

Resident synoviocytes and synovial microvasculature, together with immune cells from circulation, contribute to pannus formation, the main pathological feature of rheumatoid arthritis (RA), leading to destruction of adjacent cartilage and bone. Seeds, fibroblast-like synoviocytes (FLSs), macrophages, dendritic cells (DCs), B cells, T cells and endothelial cells (ECs) seeds with high metabolic demands undergo metabolic reprogramming from oxidative phosphorylation to glycolysis in response to poor soil of RA synovium with hypoxia, nutrient deficiency and inflammatory stimuli. Glycolysis provides rapid energy supply and biosynthetic precursors to support pathogenic growth of these seeds. The metabolite lactate accumulated during this process in turn condition the soil microenvironment and affect seeds growth by modulating signalling pathways and directing lactylation modifications. This review explores in depth the survival mechanism of seeds with high metabolic demands in the poor soil of RA synovium, providing useful support for elucidating the etiology of RA. In addition, we discuss the role and major post-translational modifications of proteins and enzymes linked to glycolysis to inspire the discovery of novel anti-rheumatic targets.

Anti-inflammatory effects of infliximab and methotrexate on peripheral blood and synovial fluid mononuclear cells: ex vivo study

OBJECTIVE

To investigate the effects of methotrexate (MTX) and the tumour necrosis factor inhibitor infliximab (IFX) on immune cells derived from peripheral blood mononuclear cells (PBMCs) and synovial fluid mononuclear cells (SFMCs) of inflammatory arthritis patients.

METHOD

Phytohaemagglutinin (PHA)-induced proliferation of healthy donors' PBMCs and synovial intermediate monocytes (CD14+CD16+ cells) in SFMCs derived from psoriatic arthritis (PsA) and rheumatoid arthritis (RA) patients was determined by flow cytometry following co-culture with IFX and MTX. PHA-induced interferon-γ (IFN-γ) production in PBMCs was measured by enzyme-linked immunosorbent assay. The drugs' effect on mRNA expression in SFMCs was determined by quantitative polymerase chain reaction.

RESULTS

The combination of IFX 10 μg/mL + MTX 0.1 μg/mL had the strongest inhibitory effect on PBMC proliferation (91%), followed by MTX 0.1 μg/mL (86%) and IFX 10 μg/mL (49%). In PHA-stimulated PBMCs, IFN-γ production was reduced by IFX 10 μg/mL, MTX 0.1 μg/mL, and IFX 10 μg/mL + MTX 0.1 μg/mL by 68%, 90%, and 85%, respectively. In SFMCs, IFX 10 µg/mL significantly reduced CD14+CD16+ cells compared to medium (PsA 54%, p < 0.01; RA 46%, p < 0.05), while MTX had no effect on this population. IFX + MTX led to a similar suppression of CD14+CD16+ cells as achieved by IFX alone. The drugs had different impacts on SFMC gene expression.

CONCLUSION

Both IFX and MTX effectively inhibited PBMC proliferation and IFN-γ production, but only IFX reduced synovial monocytes and pro-inflammatory gene expression in SFMCs, suggesting a differential impact of IFX and MTX on critical inflammatory cell populations ex vivo.

Prune Consumption Attenuates Proinflammatory Cytokine Secretion and Alters Monocyte Activation in Postmenopausal Women: Secondary Outcome Analysis of a 12-Mo Randomized Controlled Trial: The Prune Study

BACKGROUND

Proinflammatory cytokines are implicated in the pathophysiology of postmenopausal bone loss. Clinical studies demonstrate that prunes prevent bone mineral density loss; however, the mechanism underlying this effect is unknown.

OBJECTIVE

We investigated the effect of prune supplementation on immune, inflammatory, and oxidative stress markers.

METHODS

A secondary analysis was conducted in the Prune Study, a single-center, parallel-arm, 12-mo randomized controlled trial of postmenopausal women (55-75 y old; n = 235 recruited; n = 183 completed) who were assigned to 1 of 3 groups: "no-prune" control, 50 g prune/d and 100 g prune/d groups. At baseline and after 12 mo of intervention, blood samples were collected to measure serum high-sensitivity C-reactive protein (hs-CRP), serum total antioxidant capacity (TAC), plasma 8-isoprostane, proinflammatory cytokines [interleukin (IL)-1β, IL-6, IL-8, monocyte chemoattractant protein-1, and tumor necrosis factor (TNF)-α] concentrations in plasma and lipopolysaccharide (LPS)-stimulated peripheral blood mononuclear cells (PBMCs) culture supernatants, and the percentage and activation of circulating monocytes, as secondary outcomes.

RESULTS

Prune supplementation did not alter hs-CRP, TAC, 8-isoprostane, and plasma cytokine concentrations. However, percent change from baseline in circulating activated monocytes was lower in the 100 g prune/d group compared with the control group (mean ± SD, -1.8% ± 4.0% in 100 g prune/d compared with 0.1% ± 2.9% in control; P < 0.01). Furthermore, in LPS-stimulated PBMC supernatants, the percent change from baseline in TNF-α secretion was lower in the 50 g prune/d group compared with the control group (-4.4% ± 43.0% in 50 g prune/d compared with 24.3% ± 70.7% in control; P < 0.01), and the percent change from baseline in IL-1β, IL-6, and IL-8 secretion was lower in the 100 g prune/d group compared with the control group (-8.9% ± 61.6%, -4.3% ± 75.3%, -14.3% ± 60.8% in 100 g prune/d compared with 46.9% ± 107.4%, 16.9% ± 70.6%, 39.8% ± 90.8% in control for IL-1β, IL-6, and IL-8, respectively; all P < 0.05).

CONCLUSIONS

Dietary supplementation with 50-100 g prunes for 12 mo reduced proinflammatory cytokine secretion from PBMCs and suppressed the circulating levels of activated monocytes in postmenopausal women. This trial was registered at clinicaltrials.gov as NCT02822378.

The monocyte cell surface is a unique site of autoantigen generation in rheumatoid arthritis

Although anti-citrullinated protein autoantibodies (ACPAs) are a hallmark serological feature of rheumatoid arthritis (RA), the mechanisms and cellular sources behind the generation of the RA citrullinome remain incompletely defined. Peptidylarginine deiminase IV (PAD4), one of the key enzymatic drivers of citrullination in the RA joint, is expressed by granulocytes and monocytes; however, the subcellular localization and contribution of monocyte-derived PAD4 to the generation of citrullinated autoantigens remain underexplored. In this study, we demonstrate that PAD4 displays a widespread cellular distribution in monocytes, including expression on the cell surface. Surface PAD4 was enzymatically active and capable of citrullinating extracellular fibrinogen and endogenous surface proteins in a calcium dose-dependent manner. Fibrinogen citrullinated by monocyte-surface PAD4 could be specifically recognized over native fibrinogen by a panel of eight human monoclonal ACPAs. Several unique PAD4 substrates were identified on the monocyte surface via mass spectrometry, with citrullination of the CD11b and CD18 components of the Mac-1 integrin complex being the most abundant. Citrullinated Mac-1 was found to be a target of ACPAs in 25% of RA patients, and Mac-1 ACPAs were significantly associated with HLA-DRB1 shared epitope alleles, higher C-reactive protein and IL-6 levels, and more erosive joint damage. Our findings implicate the monocyte cell surface as a unique and consequential site of extracellular and cell surface autoantigen generation in RA.

Bortezomib-loaded immunoliposomes against CD44 expressing macrophages: an interplay for inflammation resolution

Macrophage-driven inflammation is the central player in a range of pathological conditions, comprising autoimmune disorders, various cancers, as well as chronic inflammatory states like rheumatoid arthritis. Therapeutic strategies tailored to specifically target macrophage behavior have acquired substantial interest for their potential to alleviate chronic inflammation effectively. In this study, we introduce a pioneering therapeutic approach utilizing specialized CD44-targeted immunoliposomes carrying bortezomib to address inflammation at the cellular level and the significance of this strategy lies in its precision nature. Bortezomib's inhibition of the proteasome interferes with the finely-tuned mechanism that controls NFκB activation, ultimately leading to a downregulation of the inflammatory response. After performing computational docking demonstrating its strong binding affinity to the proteasome molecule, the resulting nano-construct displayed a hydrodynamic size of 144.26 ± 74.4 nm and a quasi-spherical morphology. Moreover, the nano-construct ensured a minimum shelf-life of 30 days, aiming for targeted delivery with practical longevity. Upon internalization of immunoliposomes, the interaction with CD44 receptors exhibited downstream signaling events. This included the activation of Jun amino-terminal kinases 1/2 (JNK1/2) and the extracellular-signal-regulated kinases (ERK) pathway. JNK1/2 activation may lead to the release of mitochondrial pro-apoptotic factors, triggering the intrinsic apoptotic pathway and activation of caspases, which was confirmed from the level of apoptotic gene and protein expression. The precise targeting and anti-inflammatory action of this therapy against macrophages hold promise for therapeutic interventions in a wide range of inflammatory conditions, offering a novel avenue for precision medicine in the battle against excessive inflammation.

Interaction between immuno-stem dual lineages in jaw bone formation and injury repair

The jawbone, a unique structure in the human body, undergoes faster remodeling than other bones due to the presence of stem cells and its distinct immune microenvironment. Long-term exposure of jawbones to an oral environment rich in microbes results in a complex immune balance, as shown by the higher proportion of activated macrophage in the jaw. Stem cells derived from the jawbone have a higher propensity to differentiate into osteoblasts than those derived from other bones. The unique immune microenvironment of the jaw also promotes osteogenic differentiation of jaw stem cells. Here, we summarize the various types of stem cells and immune cells involved in jawbone reconstruction. We describe the mechanism relationship between immune cells and stem cells, including through the production of inflammatory bodies, secretion of cytokines, activation of signaling pathways, etc. In addition, we also comb out cellular interaction of immune cells and stem cells within the jaw under jaw development, homeostasis maintenance and pathological conditions. This review aims to eclucidate the uniqueness of jawbone in the context of stem cell within immune microenvironment, hopefully advancing clinical regeneration of the jawbone.

Macrophage membrane-camouflaged biomimetic nanovesicles for targeted treatment of arthritis

Arthritis has become the most common joint disease globally. Current attention has shifted towards preventing the disease and exploring pharmaceutical and surgical treatments for early-stage arthritis. M2 macrophages are known for their anti-inflammatory properties and their ability to support cartilage repair, offering relief from arthritis. Whereas, it remains a great challenge to promote the beneficial secretion of M2 macrophages to prevent the progression of arthritis. Therefore, it is warranted to investigate new strategies that could use the functions of M2 macrophages and enhance its therapeutic effects. This review aims to explore the macrophage cell membrane-coated biomimetic nanovesicles for targeted treatment of arthritis such as osteoarthritis (OA), rheumatoid arthritis (RA), and gouty arthritis (GA). Cell membrane-camouflaged biomimetic nanovesicle has attracted increasing attention, which successfully combine the advantages and properties of both cell membrane and delivered drug. We discuss the roles of macrophages in the pathophysiology and therapeutic targets of arthritis. Then, the common preparation strategies of macrophage membrane-coated nanovesicles are concluded. Moreover, we investigate the applications of macrophage cell membrane-camouflaged nanovesicles for arthritis, such as OA, RA, and GA. Taken together, macrophage cell membrane-camouflaged nanovesicles hold the tremendous prospect for biomedical applications in the targeted treatment of arthritis.

Osteoimmunology: The Crosstalk between T Cells, B Cells, and Osteoclasts in Rheumatoid Arthritis

Rheumatoid arthritis (RA) is an ongoing inflammatory condition that affects the joints and can lead to severe damage to cartilage and bones, resulting in significant disability. This condition occurs when the immune system becomes overactive, causing osteoclasts, cells responsible for breaking down bone, to become more active than necessary, leading to bone breakdown. RA disrupts the equilibrium between osteoclasts and osteoblasts, resulting in serious complications such as localized bone erosion, weakened bones surrounding the joints, and even widespread osteoporosis. Antibodies against the receptor activator of nuclear factor-κB ligand (RANKL), a crucial stimulator of osteoclast differentiation, have shown great effectiveness both in laboratory settings and actual patient cases. Researchers are increasingly focusing on osteoclasts as significant contributors to bone erosion in RA. Given that RA involves an overactive immune system, T cells and B cells play a pivotal role by intensifying the immune response. The imbalance between Th17 cells and Treg cells, premature aging of T cells, and excessive production of antibodies by B cells not only exacerbate inflammation but also accelerate bone destruction. Understanding the connection between the immune system and osteoclasts is crucial for comprehending the impact of RA on bone health. By delving into the immune mechanisms that lead to joint damage, exploring the interactions between the immune system and osteoclasts, and investigating new biomarkers for RA, we can significantly improve early diagnosis, treatment, and prognosis of this condition.

The role of the CX3CL1/CX3CR1 axis as potential inflammatory biomarkers in subjects with periodontitis and rheumatoid arthritis: A systematic review

OBJECTIVE

This systematic review aimed to investigate the role of the C-X3-C motif ligand 1/chemokine receptor 1 C-X3-C motif (CX3CL1/CX3CR1) axis in the pathogenesis of periodontitis. Furthermore, as a secondary objective, we determine whether the CX3CL1/CX3CR1 axis could be considered complementary to clinical parameters to distinguish between periodontitis and rheumatoid arthritis (RA) and/or systemically healthy subjects.

METHODS

The protocol used for this review was registered in OSF (10.17605/OSF.IO/KU8FJ). This study was designed following Preferred Reporting Items for Systematic Review and Meta-Analysis guidelines. Records were identified using different search engines (PubMed/MEDLINE, Scopus, Science Direct, and Web of Science) from August 10, 2006, to September 15, 2023. The observational studies on human subjects diagnosed with periodontitis and RA and/or systemically healthy were selected to analyze CX3CL1 and CX3CR1 biomarkers. The methodological validity of the selected articles was assessed using NIH.

RESULTS

Six articles were included. Biological samples (gingival crevicular fluid [GCF], saliva, gingival tissue biopsies, serum) from 379 subjects (n = 275 exposure group and n = 104 control group) were analyzed. Higher CX3CL1 and CX3CR1 chemokine levels were found in subjects with periodontitis and RA compared with periodontal and systemically healthy subjects.

CONCLUSION

Very few studies highlight the role of the CX3CL1/CX3CR1 axis in the pathogenesis of periodontitis; however, increased levels of these chemokines are observed in different biological samples (GCF, gingival tissue, saliva, and serum) from subjects with periodontitis and RA compared with their healthy controls. Future studies should focus on long-term follow-up of subjects and monitoring changes in cytokine levels before and after periodontal therapy to deduce an appropriate interval in health and disease conditions.

New Insights into the Pro-Inflammatory and Osteoclastogenic Profile of Circulating Monocytes in Osteoarthritis Patients

Osteoarthritis (OA) is a degenerative condition of the articular cartilage with chronic low-grade inflammation. Monocytes have a fundamental role in the progression of OA, given their implication in inflammatory responses and their capacity to differentiate into bone-resorbing osteoclasts (OCLs). This observational-experimental study attempted to better understand the molecular pathogenesis of OA through the examination of osteoclast progenitor (OCP) cells from both OA patients and healthy individuals (25 OA patients and healthy samples). The expression of osteoclastogenic and inflammatory genes was analyzed using RT-PCR. The OA monocytes expressed significantly higher levels of CD16, CD115, TLR2, Mincle, Dentin-1, and CCR2 mRNAs. Moreover, a flow cytometry analysis showed a significantly higher surface expression of the CD16 and CD115 receptors in OA vs. healthy monocytes, as well as a difference in the distribution of monocyte subsets. Additionally, the OA monocytes showed a greater osteoclast differentiation capacity and an enhanced response to an inflammatory stimulus. The results of this study demonstrate the existence of significant differences between the OCPs of OA patients and those of healthy subjects. These differences could contribute to a greater understanding of the molecular pathogenesis of OA and to the identification of new biomarkers and potential drug targets for OA.

Research progress of targeted therapy regulating Th17/Treg balance in bone immune diseases

Rheumatoid arthritis (RA) and postmenopausal osteoporosis (PMOP) are common bone-immune diseases. The imbalance between helper (Th17) and regulatory T cells (Tregs) produced during differentiation of CD4+ T cells plays a key regulatory role in bone remodelling disorders in RA and PMOP. However, the specific regulatory mechanism of this imbalance in bone remodelling in RA and PMOP has not been clarified. Identifying the regulatory mechanism underlying the Th17/Treg imbalance in RA and PMOP during bone remodelling represents a key factor in the research and development of new drugs for bone immune diseases. In this review, the potential roles of Th17, Treg, and Th17/Treg imbalance in regulating bone remodelling in RA and PMOP have been summarised, and the potential mechanisms by which probiotics, traditional Chinese medicine compounds, and monomers maintain bone remodelling by regulating the Th17/Treg balance are expounded. The maintenance of Th17/Treg balance could be considered as an therapeutic alternative for the treatment of RA and PMOP. This study also summarizes the advantages and disadvantages of conventional treatments and the quality of life and rehabilitation of patients with RA and PMOP. The findings presented her will provide a better understanding of the close relationship between bone immunity and bone remodelling in chronic bone diseases and new ideas for future research, prevention, and treatment of bone immune diseases.

Peptoniphilus gorbachii alleviates collagen-induced arthritis in mice by improving intestinal homeostasis and immune regulation

Introduction

The intricate connection between gut microbiota and rheumatoid arthritis (RA) pathogenesis has gained prominence, although the specific microbial species contributing to RA development remain largely unknown. Recent studies have sought to comprehensively explore alterations in the human microbiome, focusing on identifying disease-related microbial species through blood analysis. Consequently, this study aimed to identify RA-associated microbial species using a serum microbial array system and to investigate the efficacy and underlying mechanisms of potential microbial species for RA treatment.

Methods

Serum immunoglobulin M levels against 384 intestinal microbial species were assessed using a microbial microarray in patients with RA and healthy individuals. We investigated the therapeutic potential of the identified microbial candidate regarding arthritis development, immune responses, gut barrier function, and gut microbiome using a collagen-induced arthritis (CIA) mouse model.

Results

Our findings revealed significant alterations in antibody levels against 36 microbial species in patients with RA compared to healthy individuals. Notably, the antibody levels against Peptoniphilus gorbachii (PG) were decreased in patients with RA and exhibited an inverse correlation with RA disease activity. In vitro experiments demonstrated that PG produced acetate and butyrate, while exhibiting anti-inflammatory properties. In CIA mice, PG administration suppressed arthritis symptoms, reduced the accumulation of inflammatory monocytes in the mesenteric lymph nodes, and downregulated gene expression of pro-inflammatory cytokines in the ileum. Additionally, PG supplementation restored intestinal barrier integrity and partially resolved gut microbial dysbiosis in CIA mice. The fecal microbiota in PG-treated mice corresponded to improved intestinal barrier integrity and reduced inflammatory responses.

Conclusion

This study highlights the potential of serum-based detection of anti-microbial antibodies to identify microbial targets at the species level for RA treatment. Moreover, our findings suggest that PG, identified through the microbial microarray analysis, holds therapeutic potential for RA by restoring intestinal barrier integrity and suppressing the immunologic response associated with RA.

Liposomal AntagomiR-155-5p Restores Anti-Inflammatory Macrophages and Improves Arthritis in Preclinical Models of Rheumatoid Arthritis

OBJECTIVE

We previously reported an increased expression of microRNA-155 (miR-155) in the blood monocytes of patients with rheumatoid arthritis (RA) that could be responsible for impaired monocyte polarization to anti-inflammatory M2-like macrophages. In this study, we employed two preclinical models of RA, collagen-induced arthritis and K/BxN serum transfer arthritis, to examine the therapeutic potential of antagomiR-155-5p entrapped within PEGylated (polyethylene glycol [PEG]) liposomes in resolution of arthritis and repolarization of monocytes towards the anti-inflammatory M2 phenotype.

METHODS

AntagomiR-155-5p or antagomiR-control were encapsulated in PEG liposomes of 100 nm in size and -10 mV in zeta potential with high antagomiR loading efficiency (above 80%). Mice were injected intravenously with 1.5 nmol/100 μL PEG liposomes containing antagomiR-155-5p or control after the induction of arthritis.

RESULTS

We demonstrated the biodistribution of fluorescently tagged PEG liposomes to inflamed joints one hour after the injection of fluorescently tagged PEG liposomes, as well as the liver's subsequent accumulation after 48 hours, indicative of hepatic clearance, in mice with arthritis. The injection of PEG liposomes containing antagomiR-155-5p decreased arthritis score and paw swelling compared with PEG liposomes containing antagomiR-control or the systemic delivery of free antagomiR-155-5p. Moreover, treatment with PEG liposomes containing antagomiR-155-5p led to the restoration of bone marrow monocyte defects in anti-inflammatory macrophage differentiation without any significant functional change in other immune cells, including splenic B and T cells.

CONCLUSION

The injection of antagomiR-155-5p encapsulated in PEG liposomes allows the delivery of small RNA to monocytes and macrophages and reduces joint inflammation in murine models of RA, providing a promising strategy in human disease.

Monocyte-related cytokines/chemokines in cerebral ischemic stroke

AIMS

Ischemic stroke is one of the leading causes of death worldwide and the most common cause of disability in Western countries. Multiple mechanisms contribute to the development and progression of ischemic stroke, and inflammation is one of the most important mechanisms.

DISCUSSION

Ischemia induces the release of adenosine triphosphate/reactive oxygen species, which activates immune cells to produce many proinflammatory cytokines that activate downstream inflammatory cascades to induce fatal immune responses. Research has confirmed that peripheral blood immune cells play a vital role in the immunological cascade after ischemic stroke. The role of monocytes has received much attention among numerous peripheral blood immune cells. Monocytes induce their effects by secreting cytokines or chemokines, including CCL2/CCR2, CCR4, CCR5, CD36, CX3CL1/CX3CR1, CXCL12(SDF-1), LFA-1/ICAM-1, Ly6C, MMP-2/9, NR4A1, P2X4R, P-selectin, CD40L, TLR2/4, and VCAM-1/VLA-4. Those factors play important roles in the process of monocyte recruitment, migration, and differentiation.

CONCLUSION

This review focuses on the function and mechanism of the cytokines secreted by monocytes in the process of ischemic stroke and provides novel targets for treating cerebral ischemic stroke.

Role of soluble epoxide hydrolase in the abnormal activation of fibroblast-like synoviocytes from patients with rheumatoid arthritis

Rheumatoid arthritis (RA) is an autoimmune disease characterized by enigmatic pathogenesis. Polyunsaturated fatty acids (PUFAs) are implicated in RA's development and progression, yet their exact mechanisms of influence are not fully understood. Soluble epoxide hydrolase (sEH) is an enzyme that metabolizes anti-inflammatory epoxy fatty acids (EpFAs), derivatives of PUFAs. In this study, we report elevated sEH expression in the joints of CIA (collagen-induced arthritis) rats, concomitant with diminished levels of two significant EpFAs. Additionally, increased sEH expression was detected in both the synovium of CIA rats and in the synovium and fibroblast-like synoviocytes (FLS) of RA patients. The sEH inhibitor TPPU attenuated the migration and invasion capabilities of FLS derived from RA patients and to reduce the secretion of inflammatory factors by these cells. Our findings indicate a pivotal role for sEH in RA pathogenesis and suggest that sEH inhibitors offer a promising new therapeutic strategy for managing RA.