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

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.

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.

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.

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.

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.

Phototherapy techniques for the management of musculoskeletal disorders: strategies and recent advances

Musculoskeletal disorders (MSDs), which include a range of pathologies affecting bones, cartilage, muscles, tendons, and ligaments, account for a significant portion of the global burden of disease. While pharmaceutical and surgical interventions represent conventional approaches for treating MSDs, their efficacy is constrained and frequently accompanied by adverse reactions. Considering the rising incidence of MSDs, there is an urgent demand for effective treatment modalities to alter the current landscape. Phototherapy, as a controllable and non-invasive technique, has been shown to directly regulate bone, cartilage, and muscle regeneration by modulating cellular behavior. Moreover, phototherapy presents controlled ablation of tumor cells, bacteria, and aberrantly activated inflammatory cells, demonstrating therapeutic potential in conditions such as bone tumors, bone infection, and arthritis. By constructing light-responsive nanosystems, controlled drug delivery can be achieved to enable precise treatment of MSDs. Notably, various phototherapy nanoplatforms with integrated imaging capabilities have been utilized for early diagnosis, guided therapy, and prognostic assessment of MSDs, further improving the management of these disorders. This review provides a comprehensive overview of the strategies and recent advances in the application of phototherapy for the treatment of MSDs, discusses the challenges and prospects of phototherapy, and aims to promote further research and application of phototherapy techniques.

An unbiased proteomic analysis of PAD4 in human monocytes: novel substrates, binding partners and subcellular localizations

Peptidylarginine deiminase IV (PAD4) post-translationally converts arginine residues in proteins to citrullines and is implicated in playing a central role in the pathogenesis of several diseases. Although PAD4 was historically thought to be a nuclear enzyme, recent evidence has revealed a more complex localization of PAD4 with evidence of additional cytosolic and cell surface localization and activity. However, the mechanisms by which PAD4, which lacks conventional secretory signal sequences, traffics to extranuclear localizations are unknown. In this study, we show that PAD4 was enriched in the organelle fraction of monocytes with evidence of citrullination of organelle proteins. We also demonstrated that PAD4 can bind to several cytosolic, nuclear and organelle proteins that may serve as binding partners for PAD4 to traffic intracellularly. Additionally, cell surface expression of PAD4 increased with monocyte differentiation into monocyte-derived dendritic cells and co-localized with several endocytic/autophagic and conventional secretory pathway markers, implicating the use of these pathways by PAD4 to traffic within the cell. Our results suggest that PAD4 is expressed in multiple subcellular localizations and may play previously unappreciated roles in physiological and pathological conditions. This article is part of the Theo Murphy meeting issue 'The virtues and vices of protein citrullination'.

C-C Motif Chemokine Ligand 2 Enhances Macrophage Chemotaxis, Osteogenesis, and Angiogenesis during the Inflammatory Phase of Bone Regeneration

Local cell therapy has recently gained attention for the treatment of joint diseases and fractures. Mesenchymal stem cells (MSCs) are not only involved in osteogenesis and angiogenesis, but they also have immunomodulatory functions, such as inducing macrophage migration during bone regeneration via macrophage crosstalk. C-C motif chemokine ligand 2 (CCL2), a known inflammatory mediator, is associated with the migration of macrophages during inflammation. This study examined the utility of CCL2 as a therapeutic target for local cell therapy. Using lentiviral vectors for rabbit MSCs, genetically modified CCL2 overexpressing MSCs were generated. Osteogenic differentiation assays were performed using MSCs with or without macrophages in co-culture, and cell migration assays were also performed. Additionally, co-cultures were performed with endothelial cells (ECs), and angiogenesis was evaluated using a tube formation assay. Overexpression of CCL2 did not affect bone formation under monoculture conditions but promoted chemotaxis and osteogenesis when co-cultured with macrophages. Furthermore, CCL2-overexpression promoted tube formation in co-culture with ECs. These results suggest that CCL2 induces macrophage chemotaxis and osteogenesis by promoting crosstalk between MSCs and macrophages; CCL2 also stimulates ECs to induce angiogenesis. These findings indicate that CCL2 may be a useful therapeutic target for local cell therapy in areas of bone loss.

Xuelian injection ameliorates complete Freund's adjuvant-induced acute arthritis in rats via inhibiting TLR4 signaling

Background

Xuelian injection (XI), a classic preparation extracted from Saussureae Involucratae Herba, has been clinically used to manage rheumatoid arthritis (RA) for nearly twenty years in China. However, the underlying anti-RA mechanism of XI remains unclear. In this study, complete Freund's adjuvant (CFA)-induced acute arthritic model was used to examine the anti-RA effects of XI in vivo. The molecular mechanisms of this action were further investigated using lipopolysaccharide (LPS)-stimulated RAW 264.7 macrophages.

Methods

XI and XI freeze dried powder were characterized by UPLC analysis. CD68 and TLR4 expression in the ankle joints was measured by immunohistochemistry. The secretion of inflammatory mediators was detected by ELISA. The expression levels of TLR4 involved components were measured by Western blotting. The localization of transcription factors was measured by immunofluorescence assay.

Results

XI treatment ameliorated arthritic symptoms induced by CFA in the ankle joints of rats. The serum levels of inflammatory mediators, including TNF-α, MCP-1, and Rantes were decreased by XI treatment. The elevation of CD68 and TLR4 levels in ankle joints caused by CFA was suppressed by XI treatment. Moreover, XI treatment inhibited the secretion of nitric oxide and prostaglandin E2 in LPS-treated RAW264.7 macrophages. The expression of their enzymes iNOS and COX-2 was also decreased after XI treatment. The production of inflammatory mediators, including TNF-α, IL-6, IL-1β, MCP-1, MIP-1α, and Rantes was reduced by XI treatment in LPS-stimulated RAW264.7 cells. The phosphorylation of p38, JNK, ERK, TBK1, IKKα/β, IκB, p65, c-Jun, and IRF3 was reduced after XI treatment. Additionally, the expression levels of nuclear proteins of p65, c-Jun, and IRF3 were inhibited by XI treatment.

Conclusions

Taken together, XI possesses potential anti-RA effect and the underlying mechanism may be closely associated with the inhibition of TLR4 signaling. Our findings provide further pharmacological justifications for the clinical use of XI in RA treatment.

Inflammation is responsible for systemic bone loss in patients with seropositive rheumatoid arthritis treated with rituximab

BACKGROUND/AIMS

We investigated the effect of rituximab on systemic bone metabolism in patients with seropositive rheumatoid arthritis (RA).

METHODS

Twenty seropositive patients with RA were enrolled and administered one cycle of rituximab. If RA became active for > 6 months after the first rituximab cycle, a second cycle was initiated; otherwise, no additional treatment was administered. Patients were divided into two groups according to the number of rituximab treatment cycles.

RESULTS

In patients treated with a second cycle, the total hip bone mineral density (BMD) was clinically low, whereas the serum levels of receptor activator of nuclear factor kappa-B ligand (RANKL) were increased at 12 months. BMD in patients treated with one cycle did not change at 12 months, whereas serum RANKL levels decreased at all time points. DAS28 activity improved in both groups from baseline to 4 months; however, from 4 to 12 months, DAS28 activity worsened in the develgroup with the second cycle but remained stable in the group with one cycle.

CONCLUSION

Systemic inflammation, reflected by increased disease activity, may be responsible for the increase in RANKL levels, which causes systemic bone loss in rituximab-treated patients with RA. Although rituximab affects inflammation, it does not seem to alter systemic bone metabolism in RA.

Transport by circulating myeloid cells drives liposomal accumulation in inflamed synovium

The therapeutic potential of liposomes to deliver drugs into inflamed tissue is well documented. Liposomes are believed to largely transport drugs into inflamed joints by selective extravasation through endothelial gaps at the inflammatory sites, known as the enhanced permeation and retention effect. However, the potential of blood-circulating myeloid cells for the uptake and delivery of liposomes has been largely overlooked. Here we show that myeloid cells can transport liposomes to inflammatory sites in a collagen-induced arthritis model. It is shown that the selective depletion of the circulating myeloid cells reduces the accumulation of liposomes up to 50-60%, suggesting that myeloid-cell-mediated transport accounts for more than half of liposomal accumulation in inflamed regions. Although it is widely believed that PEGylation inhibits premature liposome clearance by the mononuclear phagocytic system, our data show that the long blood circulation times of PEGylated liposomes rather favours uptake by myeloid cells. This challenges the prevailing theory that synovial liposomal accumulation is primarily due to the enhanced permeation and retention effect and highlights the potential for other pathways of delivery in inflammatory diseases.

Adipocytes in the Uterine Wall during Experimental Healing and in Cesarean Scars during Pregnancy

We have suggested that adipocytes in uterine scars may affect the development of the placenta accrete spectrum (PAS). In the experimental part, we explored adipocytes in the uterine wall by the twelfth sexual cycle after surgery. In the clinical part, we investigated adipocyte clusters in the cesarean scar of pregnant women with and without PAS. The uterine wall was evaluated in gross and histological sections using morphometry, histochemistry (hematoxylin and eosin stain, Mallory stain), and immunohistochemistry for FABP4 (adipocyte markers), CD68, CD163, CD206 (macrophages), CD 34 (endothelium), cytokeratin 8 (epithelium), aSMA (smooth muscle cells). The design included an experimental study on Sprague-Dawley rats (n = 18) after a full-thickness surgical incision on the seventh (n = 6), 30th (n = 6), and 60th day (n = 6). The clinical groups include pregnant women without uterine scars (n = 10), pregnant women with a uterine scar after previous cesarean sections (n = 10), and women with PAS (n = 11). Statistical processing was carried out using nonparametric methods. Comparisons were conducted using the Mann-Whitney U-test and Kruskal-Wallis test. Statistical significance was considered at p < 0.05. On the seventh day, the rat uterine horn was enveloped by adipose tissue, which contained crown-like structures with FABP4+, CD68+, CD206+, and CD163+ cells. FABP4+ cells in the uterine wall were absent by the 30th day. The number of CD206+ and CD163+ cells in the adipose tissue decreased by the 30th day. On the 60th day, the attachment of fat tissue was revealed in the form of single strands. The serous layer around the damaged area totally recovered on the 60th day. FABP4+ cells were not detected in the uterine wall samples from pregnant women without a previous cesarean section. Adipocytes were found in the scar during non-complicated pregnancy and with PAS. Reducing the number of CD68+ cells in adipocyte clusters, there were in myometrium with PAS. Increased CD206+ and CD163+ cells were revealed in uterine adipocyte clusters of the group. According to the experimental finding, adipocytes should be absent in the uterine wall by the 12th sexual cycle after a full-thickness surgical incision. The presence of adipocyte clusters in cesarean scar indicated the disturbance of cell interaction. Differences in the numbers of CD206 and CD163 cells in adipocyte clusters between groups with and without PAS may be indirect evidence that uterine adipocytes affect the development of PAS.

Methyl Canthin-6-one-2-carboxylate Restrains the Migration/Invasion Properties of Fibroblast-like Synoviocytes by Suppressing the Hippo/YAP Signaling Pathway

Rheumatoid arthritis (RA) is an inflammatory condition that causes severe cartilage degradation and synovial damage in the joints with multiple systemic implications. Previous studies have revealed that fibroblast-like synoviocytes (FLSs) play a pivotal role in the pathogenesis of RA. The appropriate regulation of FLS function is an efficient approach for the treatment of this disease. In the present study, we explored the effects of methyl canthin-6-one-2-carboxylate (Cant), a novel canthin-6-one alkaloid, on the function of FLSs. Our data showed that exposure to Cant significantly suppressed RA-FLS migration and invasion properties in a dose-dependent manner. Meanwhile, pre-treatment with Cant also had an inhibitory effect on the release of several pro-inflammatory cytokines, including IL-6 and IL-1β, as well as the production of MMP1 and MMP3, which are important mediators of FLS invasion. In further mechanistic studies, we found that Cant had an inhibitory effect on the Hippo/YAP signaling pathway. Treatment with Cant suppressed YAP expression and phosphorylation on serine 127 and serine 397 while enhancing LATS1 and MST1 levels, both being important upstream regulators of YAP. Moreover, YAP-specific siRNA or YAP inhibition significantly inhibited wound healing as well as the migration and invasion rate of FLS cells, an impact similar to Cant treatment. Meanwhile, the over-expression of YAP significantly reversed the Cant-induced decline in RA-FLS cell migration and invasion, indicating that YAP was required in the inhibitory effect of Cant on the migration and invasion of RA-FLS cells. Additionally, supplementation of MMP1, but not MMP3, in culture supernatants significantly reversed the inhibitory effect of Cant on RA-FLS cell invasion. Our data collectively demonstrated that Cant may suppress RA-FLS migration and invasion by inhibiting the production of MMP1 via inhibiting the YAP signaling pathway, suggesting a potential of Cant for the further development of anti-RA drugs.

Transcriptomic characterization of classical monocytes highlights the involvement of immuno-inflammation in bone erosion in Rheumatoid Arthritis

Introduction

Evidence-based data suggest that under inflammatory conditions, classical monocytes are the main source of osteoclasts and might be involved in bone erosion pathophysiology. Here, we analyze the transcriptomic profile of classical monocytes in erosive and non-erosive rheumatoid arthritis patients in order to better understand their contribution to bone erosion.

Methods

Thirty-nine premenopausal RA patients were consecutively enrolled and divided into two groups based on the presence of bone erosions on hand joints. Classical monocytes were isolated from peripheral blood through negative selection, and RNA-seq was performed using a poly-A enrichment kit and Illumina® platform. Classical monocytes transcriptome from healthy age-matched women were also included to identify differentially expressed genes (DEGs). Therefore, gene sets analysis was performed to identify the enriched biological pathways.

Results

RNA-seq analysis resulted in the identification of 1,140 DEGs of which 89 were up-regulated and 1,051 down-regulated in RA patients with bone erosion compared to those without bone erosions. Among up-regulated genes, there was a highlighted expression of IL18RAP and KLF14 related to the production of pro-inflammatory cytokines, innate and adaptive immune response. Genes related to collagen metabolism (LARP6) and bone formation process (PAPPA) were down-regulated in RA patients with erosions. Enriched pathways in patients with erosions were associated with greater activation of immune activation, and inflammation. Interestingly, pathways associated with osteoblast differentiation and regulation of Wnt signaling were less activated in RA patients with erosions.

Conclusion

These findings suggest that alterations in expression of monocyte genes related to the inflammatory process and impairment of bone formation might have an important role in the pathophysiology of bone erosions in RA patients.

pH/NIR-responsive and self-healing coatings with bacteria killing, osteogenesis, and angiogenesis performances on magnesium alloy

Although biodegradable polymer coatings can impede corrosion of magnesium (Mg)-based orthopedic implants, they are prone to excessive degradation and accidental scratching in practice. Bone implant-related infection and limited osteointegration are other factors that adversely impact clinical application of Mg-based biomedical implants. Herein, a self-healing polymeric coating is constructed on the Mg alloy together with incorporation of a stimuli-responsive drug delivery nanoplatform by a spin-spray layer-by-layer (SSLbL) assembly technique. The nanocontainers are based on simvastatin (SIM)-encapsulated hollow mesoporous silica nanoparticles (S@HMSs) modified with polydopamine (PDA) and polycaprolactone diacrylate (PCL-DA) bilayer. Owing to the dynamic reversible reactions, the hybrid coating shows a fast, stable, and cyclical water-enabled self-healing capacity. The antibacterial assay indicates good bacteria-killing properties under near infrared (NIR) irradiation due to synergistic effects of hyperthermia, reactive oxygens species (ROS), and SIM leaching. In vitro results demonstrate that NIR laser irradiation promotes the cytocompatibility, osteogenesis, and angiogenesis. The coating facilitates alkaline phosphatase activity and expedites extracellular matrix mineralization as well as expression of osteogenesis-related genes. This study reveals a useful strategy to develop multifunctional coatings on bioabsorbable Mg alloys for orthopedic implants.

The effect of the Litcubanine A on the treatment of murine experimental periodontitis by inhibiting monocyte-macrophage chemotaxis and osteoclast differentiation

BACKGROUND

Periodontal disease is an inflammatory disease of periodontal tissues that is closely connected with systemic diseases. During periodontitis, the inappropriate recruitment and activation of monocytes-macrophages causes an increase in osteoclast activity and disrupts bone homeostasis. Therefore, it is a promising therapeutic strategy to treat periodontitis by regulating the functions of monocytes-macrophages. Litcubanine A (LA) is an isoquinoline alkaloid extracted from the traditional Chinese medicine Litsea cubeba, which was proven to have reproducible anti-inflammatory effects, but its regulatory role on bone homeostasis in periodontitis is still not clear.

METHODS

In this study, zebrafish experiments and a mouse ligature-induced periodontitis model were performed, and histological analysis was used to investigate the effect of LA on macrophage chemotaxis under the inflammatory environment. Real-time PCR was used to detect the regulatory effect of LA (100 nM ~ 100 μM) on the chemotaxis function of macrophages induced by LPS. Apoptosis assay and flow cytometry were used to elucidate the influence of LA on macrophage apoptosis and proliferation. To further clarify the regulatory role of LA on macrophage osteoclast differentiation, real-time PCR, histological analysis, western blot, and micro-computed tomography (micro-CT) were performed in vivo and in vitro to verify the impact of LA on bone homeostasis.

RESULTS

Compared with the control group, the chemotaxis function of macrophage was significantly attenuated by LA in vivo. LA could significantly inhibit the expression of genes encoding the chemokine receptors Ccr1 and Cxcr4, and its ligand chemokine Cxcl12 in macrophages, and suppresses the differentiation of osteoclastic precursors to osteoclasts through the MAPK signaling pathway. There were significantly lower osteoclast differentiation and bone loss in the LA group compared with the control in the ligature-induced periodontitis model.

CONCLUSION

LA is a promising candidate for the treatment of periodontitis through its reproducible functions of inhibiting monocyte-macrophage chemotaxis and osteoclast differentiation.

Human CXCR1 knock-in mice infer functional expression of a murine ortholog

Targeting CXCR1 and CXCR2 chemokine receptors to block neutrophil migration to sites of inflammation is a promising therapeutic approach for various inflammatory and autoimmune diseases. However, assessing the translational potential of such therapies using mouse models is challenging due to the unclear expression of CXCR1 at the protein level. Although CXCR2 has been well characterized in both mice and humans, the protein-level expression of CXCR1 in mice (mCXCR1) remains controversial. To address this issue, we generated a novel human CXCR1 knock-in (hCXCR1 KI) mouse model in which the transgene is under the control of the native mouse promoter and regulatory elements. Using an anti-human CXCR1 monoclonal antibody (anti-hCXCR1 monoclonal antibody), we found that hCXCR1 was highly expressed on neutrophils in the hCXCR1 KI mice, comparable to levels observed in human neutrophils. This successful expression of hCXCR1 in this mouse model suggests that functional mCXCR1 likely exists. To investigate the functional role of CXCR1, we investigated how antagonizing this receptor using anti-hCXCR1 monoclonal antibody in the arthritis model would affect disease outcomes. Antibody treatment significantly alleviated all signs of joint inflammation. In summary, our newly generated hCXCR1 KI transgenic mice provide a valuable tool to investigate the therapeutic efficacy of small molecules or monoclonal antibodies that antagonize this receptor in neutrophil-mediated pathologies.

Hyaluronic acid-based M1 macrophage targeting and environmental responsive drug releasing nanoparticle for enhanced treatment of rheumatoid arthritis

Herein, hyaluronic acid (HA) and β-cyclodextrin (β-CD) is used to form targeted drug delivery platform HCPC/DEX NPs with previously prepared carbon dots (CDs) as cross-linker, dexamethasone (DEX) is loaded for rheumatoid arthritis (RA) treatment. The drug loading capacity of β-CD and M1 macrophage targeting of HA were utilized for efficient delivery of DEX to the inflammatory joints. Because of the environmental responsive degradation of HA, DEX can be released in 24 h and inhibit the inflammatory response in M1 macrophages. The drug loading of NPs is 4.79 %. Cellular uptake evaluation confirmed that NPs can specifically target to M1 macrophages via HA ligands, the uptake of M1 macrophages is 3.7 times that of normal macrophages. In vivo experiments revealed that NPs can accumulate in RA joints to alleviate inflammation and accelerate cartilage healing, the accumulation can be observed in 24 h. The cartilage thickness increased to 0.45 mm after HCPC/DEX NPs treatment, indicating its good RA therapeutic effect. Importantly, this study was the first to utilize the potential acid and reactive oxygen species responsiveness of HA to release drug and prepare M1 macrophage targeting nanodrug for RA treatment, which provides a safe and effective RA therapeutic strategy.

3,3-dimethyl-1-butanol and its metabolite 3,3-dimethylbutyrate ameliorate collagen-induced arthritis independent of choline trimethylamine lyase activity

Previous studies have identified significant alterations in intestinal carnitine metabolism in mice with collagen-induced arthritis (CIA), potentially linking bacterial dysbiosis with autoimmunity. Bacterial trimethylamine (TMA) lyases metabolize dietary carnitine to TMA, which is oxidized in the liver to trimethylamine-N-oxide (TMAO). TMAO is associated with inflammatory diseases, such as atherosclerosis, whose immunologic processes mirror that of rheumatoid arthritis (RA). Therefore, we investigated the possibility of ameliorating CIA by inhibiting TMA lyase activity using 3,3-dimethyl-1-butanol (DMB) or fluoromethylcholine (FMC). During CIA, mice were treated with 1% vol/vol DMB, 100mg/kg FMC, or vehicle. DMB-treated mice demonstrated significant (>50%) reduction in arthritis severity compared to FMC and vehicle-treated mice. However, in contrast to FMC, DMB treatment did not reduce cecal TMA nor circulating TMAO concentrations. Using gas chromatography, we confirmed the effect of DMB is independent of TMA lyase inhibition. Further, we identified a novel host-derived metabolite of DMB, 3,3-dimethyl-1-butyric acid (DMBut), which also significantly reduced disease and proinflammatory cytokines in CIA mice. Altogether, our study suggests that DMB the immunomodulatory activity of DMB and/or its metabolites are protective in CIA. Elucidating its target and mechanism of action may provide new directions for RA therapeutic development.

Parameters of TNF receptor co-expression in allergic and autoimmune processes: Differences and diagnostic significance

The authors used a method quantitative estimation density of TNFR1/TNFR2 on cells by flow cytometry with calibration particles, which allowed them to estimate the absolute number of receptors on cells regardless of the type of flow cytometer. The TNF receptor expression parameters were used to determine their association with the fact of disease and to build diagnostic models. The proposed methodological approach using a combination of flow cytometry and mathematical modeling techniques represents a promising direction for testing the diagnostic and prognostic significance of the studied biomarkers. The multifactorial regression analysis constructed on the basis of this approach made it possible to refine and supplement diagnostic schemes for determining the probability of rheumatoid arthritis and bronchial asthma in patients.