Elevated expression of TAM receptor tyrosine kinase in synovial fluid and synovial tissue of rheumatoid arthritis

To investigate the expression and roles of TAM (Tyro3/Axl/Mer) receptor tyrosine kinases (TK) in synovial fluid and synovial tissue of patients with rheumatoid arthritis (RA). The expression of TAM TKs in the synovial fluid and synovial tissues of RA and osteoarthritis (OA) patients was measured by ELISA and immunohistochemistry. The relationships between soluble TAM TKs (sTAM TKs) levels and the clinical features, laboratory parameters and disease activity were analyzed in RA. The concentrations of sTAM TK in the synovial fluids of RA patients were increased in comparison to those of OA patients. Compared with OA patients, the expression of membrane Tyro3 TK (mTyro3 TK) and mMer TK in RA patient synovial tissue were significantly increased, which may partly explain the possible mechanism of elevated levels of sTAM TK in RA patient synovial fluid. sAxl TK levels were decreased in RA patients under sulfasalazine treatment and elevated in patients under Iguratimod treatment. Furthermore, sTyro3 TK levels were positively correlated with erythrocyte sedimentation rate (ESR) and negatively correlated with white blood cells (WBCs), red blood cells (RBCs), and hemoglobin (HB) in RA patients. The levels of sMer TK were positively associated with disease duration and rheumatoid factor (RF) and negatively correlated with HB, complement 3 (C3), and C4. Taken together, TAM TKs might be involved in RA synovial tissue inflammation.

OS10.7.A Activation of the CCR8-ACP5 axis by human microglia/macrophage derived CCL18 promotes glioma growth

Background

Glioblastoma multiforme is a highly malignant primary brain tumor with an average survival of 14 months and very limited therapeutic options. Glioma associated microglia and macrophages (GAMs) foster tumor growth by releasing several cytokines, which have only partly been identified. Here, we studied the chemokine (C-C motif) ligand 18 (CCL18), a chemokine which is only expressed in human, but not rodent GAMs, in a novel ex-vivo brain slice model including transplantation of human induced pluripotent stem cells (iPSC) derived human microglia (iMGL) and human glioma cells in to murine brain slices, which had been depleted of intrinsic murine microglia before.

Material and Methods

After establishing the humanized ex-vivo brain slice model, we performed immunohistochemical analysis (IHC) of growth and invasiveness, qrtPCR on glioma cells isolated by magnetic-activated cell sorting (MACS), functional assays measuring invasiveness, proliferation, migration and colony formation of glioma cells in vitro and in slice experiments. Corresponding studies on tumor growth and invasiveness were performed after treatment with a CCL18 neutralizing antibody, a CCR8 neutralizing antibodies and knockdown of CCR8, ACP5 (Acid Phosphatase 5) and PITPNM3 with small interfering RNA (siRNA) and short hairpin RNA (shRNA). QrtPCR, IHC and Westernblot analysis were performed on primary glioma specimens. We also conducted bioinformatic analyses, based on the TCGA GBM, GLIOVIS and GEPIA databases.

Results

We observed that CCL18 was highly expressed in GAMs, whereas CCR8 was only expressed in glioma cells. We identified the chemokine (C-C motif) receptor 8 (CCR8) as a functional receptor for CCL18 and ACP5 as an important down-stream signaling component in glioma cells. Activation of the CCL18/CCR8/ACP5 signaling pathway in human glioblastoma was associated with enhanced tumor growth and invasiveness.

Conclusion

GAMs derived CCL18 promoted glioma growth by activation of the CCR8/ACP5 axis in human glioma cells and therefore is a potential therapeutic target.

AB0058 SERUM ANTIGENOME PROFILING REVEALS DIAGNOSTIC MODELS FOR RHEUMATOID ARTHRITIS

Background

Rheumatoid arthritis (RA) is a chronic autoimmune disease that leads to joint damage, systemic inflammation and early mortality. Though the precise molecular mechanism in the triggering immune response are not fully understood, the emergence of antibodies against self-antigens can serve as diagnostic biomarker. Multiple antigens have been confirmed. However, the profiling of serum antigen, antigenome, remains poorly known.

Objectives

The study aimed to investigate the serum antigenomic profiling and determine potential diagnostic biomarkers using label-free proteomic technology implemented with machine-learning algorithm.

Methods

We captured serum antigens from a cohort consisting of 60 RA patients (45 ACPA-positive RA patients and 15 ACPA-negative RA patients), sex- and age-matched 30 osteoarthritis patients and 30 healthy controls. Liquid chromatography-tandem mass spectrometry (LC-MS/MS) was performed. We then trained a machine learning model to classify RA, ACPA-positive RA and ACPA-negative RA based on proteomic data and validated in the cohort.

Results

We identified 62, 71 and 49 differentially expressed proteins (DEPs) in RA, ACPA-positive RA and ACPA-negative RA respectively, compared to OA and healthy controls. Among these DEPs, the pathway enrichment analysis and protein-protein interactions networks were conducted. Three panels were constructed to classify RA, ACPA-positive RA and ACPA-negative RA using random forest models algorithm based on the molecular signature of DEPs, whose area under curve (AUC) were calculated as 0.9949 (95% CI = 0.9792-1), 0.9913 (95%CI = 0.9653-1) and 1.0 (95% CI = 1-1).

Conclusion

This study presented serum antigen profiling of RA. Among them, three panels of antigens were identified to classify RA, ACPA-positive and ACPA-negative RA patients as diagnostic biomarkers.

References

[1]Smolen JS, Aletaha D, McInnes IB. Rheumatoid arthritis. Lancet (London, England). (2016) 388: 2023-38. doi: 10.1016/S0140-6736(16)30173-8

[2]De Rycke L, Peene I, Hoffman IE, Kruithof E, Union A, Meheus L, et al. Rheumatoid factor and anticitrullinated protein antibodies in rheumatoid arthritis: diagnostic value, associations with radiological progression rate, and extra-articular manifestations. Ann Rheum Dis. (2004) 63: 1587-93. doi: 10.1136/ard.2003.017574

[3]Kampstra ASB, Dekkers JS, Volkov M, Dorjée AL, Hafkenscheid L, Kempers AC, et al. Different classes of anti-modified protein antibodies are induced on exposure to antigens expressing only one type of modification. Ann Rheum Dis. (2019) 78: 908-16. doi: 10.1136/annrheumdis-2018-214950

[4]Liao W, Li Z, Li T, Zhang Q, Zhang H, Wang X. Proteomic analysis of synovial fluid in osteoarthritis using swath‑mass spectrometry. Mol Med Rep. (2018) 17: 2827-36. doi: 10.3892/mmr.2017.8250

[5]Peffers MJ, Smagul A, Anderson JR. Proteomic analysis of synovial fluid: current and potential uses to improve clinical outcomes. Expert Rev Proteomic. (2019) 16: 287-302. doi:10.1080/14789450.2019.1578214

[6]Swan AL, Mobasheri A, Allaway D, Liddell S, Bacardit J. Application of machine learning to proteomics data: classification and biomarker identification in postgenomics biology. Omics: a journal of integrative biology. (2013) 17: 595-610. doi: 10.1089/omi.2013.0017

[7]Mahler M, Martinez-Prat L, Sparks JA, Deane KD. Precision medicine in the care of rheumatoid arthritis: focus on prediction and prevention of future clinically-apparent disease. Autoimmun Rev. (2020) 19: 102506. doi: 10.1016/j.autrev.2020.102506

[8]Mun S, Lee J, Park A, Kim HJ, Lee YJ, Son H, et al. Proteomics approach for the discovery of rheumatoid arthritis biomarkers using mass spectrometry. Int J Mol Sci. (2019) 20. doi: 10.3390/ijms20184368

[9]Li K, Mo W, Wu L, Wu X, Luo C, Xiao X, et al. Novel autoantibodies identified in acpa-negative rheumatoid arthritis. Ann Rheum Dis. (2021). doi: 10.1136/annrheumdis-2020-218460

Figure 1.

Study overview and antigenome characterization

Disclosure of Interests

None declared

Scavenger receptor A in immunity and autoimmune diseases: Compelling evidence for targeted therapy

INTRODUCTION

Scavenger receptor A (SR-A) is reported to be involved in innate and adaptive immunity and in recent years, the soluble form of SR-A has also been identified. Intriguingly, SR-A displays double-edged sword features in different diseases. Moreover, targeted therapy on SR-A, including genetic modulation, small molecule inhibitor, inhibitory peptides, fucoidan, and blocking antibodies, provides potential strategies for treatment. Currently, therapeutics targeting SR-A are in preclinical studies and clinical trials, revealing great perspectives in future immunotherapy.

AREAS COVERED

Through searching PubMed (January 1979-March 2022) and clinicaltrials.gov, we review most of the research and clinical trials involving SR-A. This review briefly summarizes recent study advances on SR-A, with particular concern on its role in immunity and autoimmune diseases.

EXPERT OPINION

Given the emerging evidence of SR-A in immunity, its targeted therapy has been studied in various diseases, especially autoimmune diseases. However, many challenges still remain to be overcome, such as the double-sworded effects and the specific isoform targeting. For further clinical success of SR-A targeted therapy, the crystal structure illustration and the dual function discrimination of SR-A should be further investigated. Nevertheless, although challenging, targeting SR-A would be a potential effective strategy in the treatment of autoimmune diseases and other immune-related diseases.

Adherence to antihypertensive medication and cardiovascular disease events in hypertensive patients: a dose-response meta-analysis of 2 769 700 participants in cohort study

BACKGROUND

Recently, many studies have investigated the association between adherence to antihypertensive medication (AHM) and risk of cardiovascular disease (CVD) events for hypertensive patients; however, the results varied by different studies.

AIMS

The purpose of our meta-analysis was to explore the comprehensively summarized association between AHM adherence and risk of CVD events in hypertensive patients from cohort studies.

DESIGN

A dose-response meta-analysis.

METHODS AND RESULTS

We conducted a systematic search in two databases (PubMed and Embase) from 1974 to 15 December 2019 to identify English-language reports that assessed the association of AHM adherence with risk of CVD events in cohort studies. Pooled relative risks (RRs) and 95% confidence intervals (CIs) were estimated by using a fixed- or random-effects model. Restricted cubic splines were used to evaluate the possible linear or non-linear association.

RESULTS

We included 16 cohort studies with 2 769 700 participants in the present meta-analysis. The pooled RR of CVD events was 0.66 (95% CI, 0.56-0.78, I2 = 98.6%) for the highest versus lowest AHM adherence categories. We found a linear dose-response association of AHM adherence and CVD events (Pnonlinearity = 0.887), each 20% increase in AHM adherence was associated with a 13% reduced risk of CVD events (RR 0.87, 95% CI 0.83-0.92, I2 = 98.2%) in hypertensive patients.

CONCLUSION

High AHM adherence has a protective effect on CVD events for hypertensive patients, and improving medication adherence may provide long-term CVD benefits.

Association between Sedentary Time and 6-Year All-Cause Mortality in Adults: The Rural Chinese Cohort Study

OBJECTIVES

This study aims to prospectively explore the association between sedentary time and the risk of all-cause mortality in adults based on a cohort from rural areas of China.

METHODS

The study population included 20,194 adults at baseline (2007-2008) who participated in the Rural Chinese Cohort Study. Cox's proportional hazard regression model was used to analyze the hazard ratios (HRs) and 95% confidence intervals (CIs) of sedentary time and all-cause mortality, and a restricted cubic spline was used to model the dose-response relation. We also carried out a series of sensitivity analyses to verify the robustness of our main results.

RESULTS

The median follow-up duration was 6 years, with a total of 17,265 participants (response rate 85.5%) followed up, and 1,106 deaths observed. Data for 17,048 participants were analyzed, with the mean age of participants being 52.00. Compared with sedentary time <4 h/day group, the risk of all-cause mortality was significantly increased in the 8-11 h/day (HR=1.27, 95%CI:1.03-1.56) and ≥11 h/day groups (HR=1.48, 95%CI:1.20-1.84). With increases in sedentary time, the risk of all-cause mortality increased gradually (Ptrend <0.001). For each 1 h/day increase in sedentary time, the risk of all-cause mortality increased by 3% (HR=1.03, 95%CI: 1.01-1.05). Sensitivity analyses showed our main results were consistent.

CONCLUSIONS

Prolonged sedentary time increases the risk of all-cause mortality in the adult rural Chinese population. Reducing sedentary time may have important implications for reducing mortality risk.

Serum Antigenome Profiling Reveals Diagnostic Models for Rheumatoid Arthritis

Objective

The study aimed to investigate the serum antigenomic profiling in rheumatoid arthritis (RA) and determine potential diagnostic biomarkers using label-free proteomic technology implemented with machine-learning algorithm.

Method

Serum antigens were captured from a cohort consisting of 60 RA patients (45 ACPA-positive RA patients and 15 ACPA-negative RA patients), together with sex- and age-matched 30 osteoarthritis (OA) patients and 30 healthy controls. Liquid chromatography-tandem mass spectrometry (LC-MS/MS) was then performed. The significantly upregulated and downregulated proteins with fold change > 1.5 (p < 0.05) were selected. Based on these differentially expressed proteins (DEPs), a machine learning model was trained and validated to classify RA, ACPA-positive RA, and ACPA-negative RA.

Results

We identified 62, 71, and 49 DEPs in RA, ACPA-positive RA, and ACPA-negative RA, respectively, as compared to OA and healthy controls. Typical pathway enrichment and protein-protein interaction networks were shown among these DEPs. Three panels were constructed to classify RA, ACPA-positive RA, and ACPA-negative RA using random forest models algorithm based on the molecular signature of DEPs, whose area under curve (AUC) were calculated as 0.9949 (95% CI = 0.9792-1), 0.9913 (95% CI = 0.9653-1), and 1.0 (95% CI = 1-1).

Conclusion

This study illustrated the serum auto-antigen profiling of RA. Among them, three panels of antigens were identified as diagnostic biomarkers to classify RA, ACPA-positive, and ACPA-negative RA patients.

Intestinal butyrate-metabolizing species contribute to autoantibody production and bone erosion in rheumatoid arthritis

The imbalance between pathogenic and beneficial species of the intestinal microbiome and metabolism in rheumatoid arthritis (RA) remains unclarified. Here, using shotgun-based metagenome sequencing for a treatment-naïve patient cohort and a "quasi-paired cohort" method, we observed a deficiency of butyrate-producing species and an overwhelming number of butyrate consumers in RA patients. These outcomes mainly occurred in patients with positive ACPA, with a mean AUC of 0.94. This panel was also validated in established RA with an AUC of 0.986 in those with joint deformity. In addition, we showed that butyrate promoted Tregs, while suppressing Tconvs and osteoclasts, due to potentiation of the reduction in HDAC expression and down-regulation of proinflammatory cytokine genes. Dietary butyrate supplementation conferred anti-inflammatory benefits in a mouse model by rebalancing TFH cells and Tregs, as well as reducing antibody production. These findings reveal the critical role of butyrate-metabolizing species and suggest the potential of butyrate-based therapies for RA patients.

SR-A neutralizing antibody: potential drug candidate for ameliorating osteoclastogenesis in rheumatoid arthritis

Rheumatoid arthritis (RA) is an autoimmune disease characterized by proliferative synovitis with deterioration of cartilage and bone. Osteoclasts (OCs) are the active participants in the bone destruction of RA. Although with great advances, most current therapeutic strategies for RA have limited effects on bone destruction. Macrophage scavenger receptor A (SR-A) is a class of pattern recognition receptors (PRRs) involved in bone metabolism and OC differentiation. More recently, our study revealed the critical role of SR-A in RA diagnosis and pathogenesis. Here, we further demonstrated that serum SR-A levels were positively correlated with bone destruction in patients with RA. Anti-SR-A neutralizing antibodies significantly inhibited OC differentiation and bone absorption in vitro in patients with RA, but not in healthy individuals, dampening the expression of OC-specific genes such as tartrate-resistant acid phosphatase (TRAP), cathepsin K (CTSK), and matrix metalloproteinase-9 (MMP-9). Similar results were also seen in collagen-induced arthritis (CIA) mice in vitro. Moreover, the anti-SR-A neutralizing antibody could further ameliorate osteoclastogenesis in vivo and ex vivo in CIA mice, accompanied by decreased serum levels of C-terminal telopeptide and IL-6, exhibiting potential protective effects. These results suggest that blockade of SR-A using anti-SR-A neutralizing antibodies might provide a promising therapeutic strategy for bone destruction in the RA.

Decreased perforin-producing B cells correlate with systemic lupus erythematosus

OBJECTIVES

It has been proved that B cells play indispensable roles in immunity via producing cytokines and secreting antibodies. Aberrant B cells are considered as the major participants in the pathogenesis of systemic lupus erythematosus (SLE). Recently, perforin (PFP)-producing B cell has been identified, serving as a new type of potential anti-tumour effector cells. However, the roles and characteristics of the PFP-producing B cells in SLE remain unclear.

METHODS

The frequencies of PFP-producing B cells in peripheral blood of heathy controls (HC) and SLE patients were detected by flow cytometry, and their correlation with the patient clinical and immunological features were analysed. The capacities of these cells in producing PFP were also compared between HC and SLE by RT-qPCR and ELISpot analyses.

RESULTS

In this study, we demonstrated that B cells could produce PFP and was further enhanced upon anti-BCR and IL-21 stimulation. In patients with SLE, the frequencies of these PFP-producing B cells were decreased and negatively correlated with the clinical characteristics. Further analysis revealed that SLE patients with vasculitis and pleurisy showed even lower frequencies of PFP-producing B cells.

CONCLUSIONS

These findings revealed that B cells could produce PFP, and a decrease in these cells was associated with SLE pathogenesis.

Integrating genome-wide association and transcriptome prediction model identifies novel target genes for osteoporosis

In this study, we integrated large-scale GWAS summary data and used the predicted transcriptome-wide association study method to discover novel genes associated with osteoporosis. We identified 204 candidate genes, which provide novel clues for understanding the genetic mechanism of osteoporosis and indicate potential therapeutic targets.

INTRODUCTION

Osteoporosis is a highly polygenetic disease characterized by low bone mass and deterioration of the bone microarchitecture. Our objective was to discover novel candidate genes associated with osteoporosis.

METHODS

To identify potential causal genes of the associated loci, we investigated trait-gene expression associations using the transcriptome-wide association study (TWAS) method. This method directly imputes gene expression effects from genome-wide association study (GWAS) data using a statistical prediction model trained on GTEx reference transcriptome data. We then performed a colocalization analysis to evaluate the posterior probability of biological patterns: associations characterized by a single causal variant or multiple distinct causal variants. Finally, a functional enrichment analysis of gene sets was performed using the VarElect and CluePedia tools, which assess the causal relationships between genes and a disease and search for potential gene's functional pathways. The osteoporosis-associated genes were further confirmed based on the differentially expressed genes profiled from mRNA expression data of bone tissue.

RESULTS

Our analysis identified 204 candidate genes, including 154 genes that have been previously associated with osteoporosis, 50 genes that have not been previously discovered. A biological function analysis found that 20 of the candidate genes were directly associated with osteoporosis. Further analysis of multiple gene expression profiles showed that 15 genes were differentially expressed in patients with osteoporosis. Among these, SLC11A2, MAP2K5, NFATC4, and HSP90B1 were enriched in four pathways, namely, mineral absorption pathway, MAPK signaling pathway, Wnt signaling pathway, and PI3K-Akt signaling pathway, which indicates a causal relationship with the occurrence of osteoporosis.

CONCLUSIONS

We demonstrated that transcriptome fine-mapping identifies more osteoporosis-related genes and provides key insight into the development of novel targeted therapeutics for the treatment of osteoporosis.

Casein Kinase II exacerbates rheumatoid arthritis via promoting Th1 and Th17 cell inflammatory responses

OBJECTIVES

Studies have demonstrated that CK2 is engaged in CD4⁺ T cell proliferation and activation. We investigated the potential involvement of CK2 in the pathogenesis of rheumatoid arthritis (RA).

METHODS

Peripheral blood and synovial fluid mononuclear cells (PBMC and SFMC) of RA patients, as well as splenocytes of collagen-induced arthritis (CIA) mice were treated with different doses of CK2 inhibitor CX4945 in vitro. Then, the Th1, Th2, Th17, and Treg cell responses were analyzed. In addition, CIA mice were administrated with CX4945 via oral gavage. Accordingly, the arthritis scores, bone destruction, tissue damage, and the CD4⁺ T cell subsets were assessed.

RESULTS

The expression of CK2 was upregulated in CD4⁺ T cells under RA circumstance. In vitro CX4945 treatment significantly inhibited the Th1 and Th17 cell responses, while promoted the Th2 cell responses in RA patient PBMC, SFMC and CIA mouse splenocytes, dampening IFN-γ and IL-17A production. Moreover, administration of CX4945 ameliorated the severity of arthritis in CIA mice, along with decreased Th1 and Th17 cells. However, CX4945 seemed to have minimal effect on RA Treg cells.

CONCLUSION

CK2 serves as an important regulator of the Th1 and Th17 cell axes in RA, thus contributing to the disease aggravation.

Impaired granzyme B-producing regulatory B cells in systemic lupus erythematosus

Granzyme B (GrB)-producing B cells are proposed to be a kind of regulatory B cells (Bregs) and have been revealed to be implicated in the pathogenesis of autoimmune diseases. Nevertheless, their role in SLE remains elusive. In this study, the frequencies of GrB-producing Bregs in peripheral blood of heathy control (HC) and systemic lupus erythematosus (SLE) were evaluated by flow cytometry, and their correlation with SLE patient clinical and immunological features were analyzed. The expression of GrB in HC and SLE B cells were also further detected by RT-qPCR analysis and ELISpot. The function of GrB-producing Bregs in HC and SLE patients was further investigated by in vitro CD4⁺ effector T cells-B cells co-culture assays with GrB blockade. We found that GrB-producing Bregs were significantly decreased in SLE patients and correlated with the clinical and immunological features. Moreover, these cells were functionally impaired under SLE circumstance. The negative correlation between GrB-producing Bregs and CD4⁺ T cells observed in healthy individuals disappeared in SLE patients. In vitro cell co-culture assay further showed that GrB-producing Bregs from SLE patients failed to suppress the Th1, Th2 and Th17 cell inflammatory responses, partially due to the dampened capacity of down-regulating TCR zeta and inducing T cell apoptosis. Taken together, these results revealed the disturbance of GrB-producing Bregs in SLE that might contribute to the disease initiation and progression.

P16.05 Implementation of a novel ex-vivo brain slice model to study human glioblastoma and glioma-associated microglia

BACKGROUND

Glioblastoma multiforme is a highly malignant brain tumor with a devastating prognosis. Resection followed by radio-chemotherapy leads to an overall survival of only 15 months. Up to 40% of the tumor mass consist of tumor-associated microglia and macrophages (TAMs). These cells were shown to promote tumor growth and invasiveness in many murine glioma models. The interaction between TAMs and tumor cells is crucial for tumor progression and includes several known pathways. Still, murine glioma models only partially mirror the human tumor microenvironment. Several known genes, which are highly upregulated in human glioma and TAMs are only expressed in human tissue and not in mice. To further investigate some of these genes, we aimed at establishing a humanized ex-vivo brain slice model, in which human TAMs and human glioma cells can be studied in a standardized manner.

MATERIAL AND METHODS

We used 250 micrometer thick murine brain slices, which were depleted of intrinsic microglia by applying clodoronated liposomes. Next, we inoculated human glioma cells (originating from the cell lines mCherryU87, mCherryU251MG, mCherryLN229 and several patient derived cells lines) with or without human microglia derived from induced pluripotent stem cells (iPSCs). Slices were cultivated for 7 to 14 days. Next, we performed a detailed analysis of microglia morphology (sphericity, cell body volume, process length and branching pattern) and tumor volume.

RESULTS

Clodronation efficacy was high, depending on duration of treatment and length of cultivation. iPSCs and tumor cells integrated into the slice very well. The presence of tumor cells led to an increased sphericity of iPSC-dervied microglia and to an increased cell body volume. Branching pattern and process length did not differ between both conditions. Tumor volume was significantly larger when iPSC-derived microglia were present. This was found in various glioma cells lines and also in patient derived cells.

CONCLUSION

The newly established humanized ex-vivo brain slice system was shown to be feasible. The method successfully allows to study the interaction between human TAMs and tumor cells. Microglia foster tumor growth not only in murine glioma models, but also in a human paradigm. The humanized ex-vivo brain slice model therefore is the optimal basis to study the role human-specific genes in TAM-glioma interaction.

Adherence to antihypertensive medications for secondary prevention of cardiovascular disease events: a dose-response meta-analysis

OBJECTIVES

The aim of the study was to explore the association between adherence to antihypertensive medications (AHMs) and the risk of recurrence of cardiovascular disease (CVD) events in patients with a history of CVD events from cohort studies.

STUDY DESIGN

This is a dose-response meta-analysis.

METHODS

PubMed and Embase databases were searched up to March 4, 2021, to identify English-language reports of cohort studies that assessed the association of AHM adherence with risk of recurrence of CVD events. Pooled relative risks (RRs) and 95% confidence intervals (CIs) were estimated by using a fixed- or random-effects model. Restricted cubic splines were used to evaluate the possible linear or non-linear association.

RESULTS

We included nine cohort studies (54,349 patients) in the present meta-analysis. The pooled RR of CVD events was 0.66 (95% CI, 0.54-0.78) for the highest versus lowest AHM adherence category. We did not find any evidence of non-linearity association between AHM adherence and risk of CVD events (P_{non-linearity} = 0.534); for patients with a history of CVD events, the risk of CVD events was reduced by 9% for each 20% increase in AHM adherence (RR, 0.91; 95% CI, 0.85-0.97). The results of sensitivity analysis and subgroup analysis were virtually unchanged.

CONCLUSIONS

The high level of adherence to AHM is an effective strategy for preventing recurrence of CVD events. Patients with a history of CVD events should adhere to AHM.

Double-negative (DN) B cells: an under-recognized effector memory B cell subset in autoimmunity

Human B cells could be divided into four classical subsets based on CD27 and immunoglobulin (Ig)D expression. Distinct from the other three well-studied subsets, CD27^- IgD^- B cells, also termed as double-negative (DN) B cells, have long been neglected. However, in recent years emerging evidence shows that DN B cells are unique memory B cells with important functions. They are expanded in a variety of diseases, especially in autoimmune diseases, contributing to the disease pathogenesis. Here, we briefly review the studies on DN B cells, including their origins, characteristics, subsets and roles in diseases, to try to bring new insights into this under-recognized B cell subset.

AB0046 THE EXPRESSION AND CLINICAL SIGNIFICANCE OF TAM RECEPTOR TYROSINE KINASE ON MONOCYTE SUBSETS IN RHEUMATOID ARTHRITIS

Background:

The TAM receptor tyrosine kinases (Tyro3/Axl/Mer TK) are a subfamily of receptor tyrosine kinases, the role of which in autoimmune diseases such as systemic lupus erythematosus has been well explored, while their functions in rheumatoid arthritis (RA) remain largely unknown [1].

Objectives:

The study aimed to investigate the expression and clinical significance of Tyro3, Axl and MerTK on monocyte subsets in rheumatoid arthritis (RA).

Methods:

The expression of Tyro3, Axl and MerTK on CD14+ monocytes, nonclassical monocytes (NCM, CD14+CD16++), intermediate monocytes (IM, CD14++CD16+), and classical monocytes (CM, CD14++CD16-) were evaluated in peripheral blood of RA by flow cytometry and qPCR. And the correlation between the expression of Tyro3TK and MerTK on NCM, IM, and CM with RA patient clinical feature were further analyzed.

Results:

The results revealed that the expression of Tyro3TK on CD14+ monocytes was significantly upregulated in RA patients (F = 9.18, P < 0.0001), while there was no significant difference of the expression MerTK on HC, OA, and RA, and the expression of AxlTK was minimal (Fig 1). The expression of Tyro3TK on CM was significantly upregulated in RA patients as compared with HC and osteoarthritis (OA) patients (P < 0.05, Fig 2-3), and positively correlated with the disease manifestations, such as swollen joint count (SJC), tender joint count (TJC) and the disease activity score (Fig 4).

Figure 1.

The expression of Tyro3, Axl and MerTK on CD14+ monocytes is increased in RA. (a) Gating strategy for flow cytometry of Tyro3, Axl and MerTK on CD14+ monocytes. (b) The expression of Tyro3, Axl and MerTK on CD14+ monocytes were compared between HC (n = 40), OA (n = 27), and RA patients (n = 40). *P < 0.05, **P < 0.01, ns, not significant.

Figure 2.

The expression of Tyro3TK on IM and CM were increased in RA. (a) Gating strategy for flow cytometry of TAMTK on monocyte subsets. The expression of (b) Tyro3TK and (c) MerTK on NCM, IM, and CM were compared between HC (n = 40), OA (n = 27), and RA patients (n = 40). *P < 0.05, **P < 0.01, ***P < 0.001, ns, not significant.

Figure 3.

The mRNA expression of Tyro3TK on CM is increased in RA. (a) The mRNA expression of Tyro3TK on NCM, IM, and CM in HC (n = 3) and RA (n = 3) patients. (b) The mRNA expression of MerTK on NCM, IM, and CM in HC (n = 3) and RA (n = 3) patients. **P < 0.01.

Conclusion:

These findings indicate that Tyro3TK on CM was elevated in RA patients and correlated positively with disease activity, which may serves as an important participant in RA pathogenesis.

References:

[1]Rothlin CV, Lemke G, TAM receptor signaling and autoimmune disease. Curr Opin Immunol, 2010. 22(6): p. 740-6.

Footnotes:

The study was supported by grants from the National Natural Science Foundation of China (81671609 and 81871290 to Dr. Y. Su, 82001718 to Dr. L. Xu), the Beijing Science and Technology Planning Project (Z191100006619111 to Dr. Y. Su), the Beijing Municipal Natural Science Foundation (7194329 to Dr. L. Xu).

Figure 4.

Correlation analysis of Tyro3TK on IM and CM with RA patient clinical manifestations. The associations of Tyro3TK on IM (r = 0.492, *P = 0.001) (a) and CM (r = 0.577, *P = 0.0001) (b) with RA patient swollen joint counts (SJC) were analyzed, respectively. The expression of Tyro3TK on IM and CM were also compared between different RA patient groups: (c) RA with high disease activity (DAS28-ESR > 3.2) and non-high disease activity (DAS28-ESR ≤ 3.2), (d) RA with and without swollen joints, (e) tender joints. *P < 0.05, **P < 0.01.

Disclosure of Interests:

None declared

Abstract 034: A Healthy Lifestyle Score Including Sleep Duration And Risk Of Cardiovascular Disease

Objectives: The aim of this study was to evaluate the relationship between a lifestyle score including sleep duration and CVD risk, and to estimate whether adding sleep duration into a traditional lifestyle score improved CVD risk prediction.

Methods: A prospective analysis was conducted among 67250 women in the Nurses’ Health Study and 29279 men in the Health Professionals Follow-up Study who were followed from 1986 to 2016. The traditional lifestyle score was defined as not smoking, normal BMI(18.5-24.9 kg/m 2 ), ≥30 min/d of moderate physical activity, higher diet quality (top 40% of AHEI), moderate alcohol intake (women:5-15g/day; men:5-30g/day). Low-risk sleep duration, defined as sleeping ≥6 to <8 hours/day, was included as an additional component. Cox proportion hazards regression models were used to estimate hazard ratios (HRs) and 95% confidence intervals (CIs) of CVD, CHD, and stroke. We used the likelihood ratio test and C-statistics to compare the predictive value of the two scores.

Results: A total of 11826 incident CVD cases were documented. In multivariable-adjusted models, each low-risk factor was independently and significantly associated with lower risk of CVD, CHD, and stroke. The multivariable-adjusted HRs (95% CIs) comparing six with zero low-risk factors in the healthy lifestyle score were 0.17(0.12, 0.23) for CVD, 0.15(0.10, 0.22) for CHD, and 0.19(0.12, 0.33) for stroke. Approximately 67% of CVD and CHD cases, and 62% stroke cases were attributable to poor adherence to a healthy lifestyle. P- value for likelihood ratio test comparing nested models including the traditional lifestyle score vs traditional lifestyle score plus sleep duration was <0.001. Adding sleep duration to the traditional score prediction model increased the C-statistics from 0.63 (95% CI: 0.62, 0.63) to 0.64 (95% CI: 0.63, 0.65)( P <0.001).

Conclusions: Incorporating sleep duration into traditional lifestyle scores improves prediction of CVD risk and warrants consideration for inclusion in lifestyle recommendations.

Role of IL-24 in NK cell activation and its clinical implication in systemic lupus erythematosus

OBJECTIVES

Interleukin (IL)-24 has been considered as an inflammatory cytokine in autoimmune diseases. However, conflicting data exist and its biological function remains controversial. Additionally, little is known about its functional impact on natural killer (NK) cells. The aim of this study was to investigate the role of IL-24 in NK cell activation and its clinical implication in systemic lupus erythematosus (SLE).

METHODS

Serum cohort consisting of 299 SLE patients, 214 RA patients, and 159 healthy controls (HCs) and plasma cohort consisting of 70 SLE patients, 82 RA patients, and 123 HCs were included in evaluating IL-24 concentrations. Impact of IL-24 on NK cell activation was assessed in two NK cell subsets, i.e., CD56^dimCD16⁺ and CD56^brightCD16^- NK cells. Human NK-92 cell line was applied to evaluate functional potential of IL-24 on NK cell migration and invasion.

RESULTS

Serum and plasma levels of IL-24 were comparable between patients with SLE or RA and HCs. While recombinant human (rh) IL-2 consistently induced an increased expression of CD69 on both CD56^dimCD16⁺ and CD56^brightCD16^- cells derived from both healthy subjects and patients with SLE, IL-24 alone was insufficient to activate the CD56^dim and CD56^bright NK cells. Similarly, while the migratory NK-92 cell numbers were significantly increased with rhIL-2 stimulation, IL-24 alone was unable to enhance NK-92 cell migratory and invasive capacity.

CONCLUSION

Our data indicate that there were no significant differences in serum and plasma concentrations of IL-24 between SLE patients and healthy controls. Recombinant IL-24 has no effect on NK cell activation and migration. Key points • This is the first study to investigate functional potential of IL-24 on NK cell activation. • Recombinant IL-24 lacks functional capacity on NK cell activation in either CD56^dimCD16⁺ or CD56^brightCD16^- NK cell subsets derived from both healthy subjects and patients with SLE. • No significant differences in serum and plasma levels of IL-24 between SLE patients and healthy controls.

Associations of Body Mass Index, Visceral Fat Area, Waist Circumference, and Waist-to-Hip Ratio with Cognitive Function in Western China: Results from WCHAT Study

OBJECTIVES

This study examined the relationship between cognitive performance and obesity parameters, such as body mass index (BMI), visceral fat area (VFA), waist circumference (WC), and waist-to-hip ratio (WHR) in western China.

STUDY DESIGN

A cross-sectional study.

METHODS

3914 participants, aged ≥50 years, were recruited in this study. Anthropometrics measurements, life-style factors, chronic disease comorbidities, and sleep qualities were recorded for each participant. Among the anthropometrics, BMI, WC, and WHR were assessed using standard procedures, while VFA was calculated using bioelectrical impedance analysis. Cognitive performance was estimated using the Short Portable Mental Status Questionnaire (SPMSQ). Finally, relationships between cognitive abilities and BMI, VFA, WC, and WHR were evaluated using univariate and multivariate regression analyses.

RESULTS

Cognitive decline (CD) occurred at a rate of 13.29% among the 3914 participants. A strong correlation was observed between cognitive abilities and BMI of male patients aged 50-59 yrs (OR 1.116,95% CI1.002-1.242), in the adjusted model. Alternately, WHR was shown to be significantly related to CD in females aged ≥70 years (OR 0.041, 95% CI0.002-0.671). WC was shown to have a strong association with CD in males (OR 1.023,95% CI1.003-1.024). Lastly, WHR was closely connected to CD in participants with BMI < 25 kg/m2 (OR 0.022,95% CI0.002-0.209).

CONCLUSIONS

Our findings suggest that a higher middle age BMI is associated with CD, whereas, in the elderly population, a higher WHR is related to improved cognitive performance. Further investigation is warranted to elucidate a relationship between VFA and CD.

Inactivation of TMEM106A promotes lipopolysaccharide-induced inflammation via the MAPK and NF-κB signaling pathways in macrophages

Pattern recognition receptors, such as Toll-like receptors (TLRs), play an important role in the host defense against invading microbial pathogens. Their activation must be precisely regulated, as inappropriate activation or overactivation of TLR signaling pathways may result in inflammatory disorders, such as septic shock or autoimmune diseases. TMEM106A is a type II transmembrane protein constitutively expressed in macrophages. Our current study demonstrated that TMEM106A levels were increased in macrophages upon lipopolysaccharide (LPS) stimulation, as well as in the peripheral monocytes of patients with sepsis. Tmem106a knockout mice were more sensitive to lipopolysaccharide (LPS)-induced septic shock than wild-type mice. Further experiments indicated that Tmem106a ablation enhanced the expression of CD80, CD86 and major histocompatibility complex (MHC)-II in mouse macrophages upon LPS stimulation, accompanied with up-regulation of tumor necrosis factor (TNF)-α, interleukin (IL)-6, interferon (IFN)-β and inducible nitric oxide synthase (iNOS), indicating the activation of macrophages and polarization towards the M1 inflammatory phenotype. Moreover, elevated mitogen-activated protein kinase (MAPK) and nuclear factor kappa B (NF-κB) signaling were found to be involved in the LPS-induced inflammatory response in Tmem106a^-/- macrophages. However, this effect was largely abrogated by macrophage deletion in Tmem106a^-/- mice. Therefore, deficiency of Tmem106a in macrophages may enhance the M1 polarization in mice, resulting in inflammation. This suggests that TMEM106A plays an important regulatory role in maintaining macrophage homeostasis.