Elevated expression of hsa_circ_0000479 in neutrophils correlates with features of systemic lupus erythematosus

OBJECTIVE

Accumulating evidence suggests that differentially expressed circular RNAs (circRNAs) play critical roles in immune cells of systemic lupus erythematosus (SLE) patients. Hsa_circ_0000479 has been studied in the field of cancer and infection, whereas seldom studied in autoimmune diseases. The aim of this study was to investigate the role and clinical value of neutrophil hsa_circ_0000479 in SLE.

METHODS

The expression levels of hsa_circ_0000479 in both healthy individuals and SLE patients' neutrophils were detected by qPCR and compared with those in peripheral blood mononuclear cells (PBMCs) . In addition, the correlation of hsa_circ_0000479 levels in neutrophils with the clinical and immunological features of SLE patients was also analysed.

RESULTS

The expression levels of hsa_circ_0000479 in the patients with SLE were significantly higher in neutrophils than that of PBMCs, and also significantly higher than that in healthy controls (HCs). Moreover, the expression levels of hsa_circ_0000479 in neutrophils were negatively associated with absolute neutrophil count and complement 3 (C3), whereas positively correlated with anti-dsDNA and anti-nucleosome antibodies in SLE. In addition, SLE patients with higher levels of hsa_circ_0000479 demonstrated more several clinical manifestations, including Raynaud's phenomenon, alopecia and leucopenia.

CONCLUSIONS

Hsa_circ_0000479 is up-regulated in neutrophils of SLE patients, and is also associated with several important laboratory indicators and clinical manifestations, suggesting that hsa_circ_0000479 in neutrophils was one of probable factors involved in the pathogenesis of SLE with potential clinical value.

Immunological role of Gas6/TAM signaling in hemostasis and thrombosis

The immune system is an emerging regulator of hemostasis and thrombosis. The concept of immunothrombosis redefines the relationship between coagulation and immunomodulation, and the Gas6/Tyro3-Axl-MerTK (TAM) signaling pathway builds the bridge across them. During coagulation, Gas6/TAM signaling pathway not only activates platelets, but also promotes thrombosis through endothelial cells and vascular smooth muscle cells involved in inflammatory responses. Thrombosis appears to be a common result of a Gas6/TAM signaling pathway-mediated immune dysregulation. TAM TK and its ligands have been found to be involved in coagulation through the PI3K/AKT or JAK/STAT pathway in various systemic diseases, providing new perspectives in the understanding of immunothrombosis. Gas6/TAM signaling pathway serves as a breakthrough target for novel therapeutic strategies to improve disease management. Many preclinical and clinical studies of TAM receptor inhibitors are in process, confirming the pivotal role of Gas6/TAM signaling pathway in immunothrombosis. Therapeutics targeting the TAM receptor show potential both in anticoagulation management and immunotherapy. Here, we review the immunological functions of the Gas6/TAM signaling pathway in coagulation and its multiple mechanisms in diseases identified to date, and discuss the new clinical strategies that may generated by these roles.

The complexity of glucose time series is associated with short- and long-term mortality in critically ill adults: a multi-center, prospective, observational study

BACKGROUND

The wealth of data taken from continuous glucose monitoring (CGM) remains to be fully used. We aimed to evaluate the relationship between a promising new CGM metric, complexity of glucose time series index (CGI), and mortality in critically ill patients.

METHODS

A total of 293 patients admitted to mixed medical/surgical intensive care units from 5 medical centers in Shanghai were prospectively included between May 2020 and November 2021. CGI was assessed using intermittently scanned CGM, with a median monitoring period of 12.0 days. Outcome measures included short- and long-term mortality.

RESULTS

During a median follow-up period of 1.7 years, a total of 139 (47.4%) deaths were identified, of which 73 (24.9%) occurred within the first 30 days after ICU admission, and 103 (35.2%) within 90 days. The multivariable-adjusted HRs for 30-day mortality across ascending tertiles of CGI were 1.00 (reference), 0.68 (95% CI 0.38-1.22) and 0.36 (95% CI 0.19-0.70), respectively. For per 1-SD increase in CGI, the risk of 30-day mortality was decreased by 51% (HR 0.49, 95% CI 0.35-0.69). Further adjustment for HbA1c, mean glucose during hospitalization and glucose variability partially attenuated these associations, although the link between CGI and 30-day mortality remained significant (per 1-SD increase: HR 0.57, 95% CI 0.40-0.83). Similar results were observed when 90-day mortality was considered as the outcome. Furthermore, CGI was also significantly and independently associated with long-term mortality (per 1-SD increase: HR 0.77, 95% CI 0.61-0.97).

CONCLUSIONS

In critically ill patients, CGI is significantly associated with short- and long-term mortality.

Proinflammatory phenotype of B10 and B10pro cells elicited by TNF-α in rheumatoid arthritis

OBJECTIVES

B10 and B10pro cells suppress immune responses via secreting interleukin (IL)-10. However, their regulators and underlying mechanisms, especially in human autoimmune diseases, are elusive. This study aimed to address these questions in rheumatoid arthritis (RA), one of the most common highly disabling autoimmune diseases.

METHODS

The frequencies and functions of B10 and B10pro cells in healthy individuals and patients with RA were first analysed. The effects of proinflammatory cytokines, particularly tumour necrosis factor (TNF)-α on the quantity, stability and pathogenic phenotype of these cells, were then assessed in patients with RA before and after anti-TNF therapy. The underlying mechanisms were further investigated by scRNA-seq database reanalysis, transcriptome sequencing, TNF-α-/- and B cell-specific SHIP-1-/- mouse disease model studies.

RESULTS

TNF-α was a key determinant for B10 cells. TNF-α elicited the proinflammatory feature of B10 and B10pro cells by downregulating IL-10, and upregulating interferon-γ and IL-17A. In patients with RA, B10 and B10pro cells were impaired with exacerbated proinflammatory phenotype, while anti-TNF therapy potently restored their frequencies and immunosuppressive functions, consistent with the increased B10 cells in TNF-α-/- mice. Mechanistically, TNF-α diminished B10 and B10pro cells by inhibiting their glycolysis and proliferation. TNF-α also regulated the phosphatidylinositol phosphate signalling of B10 and B10pro cells and dampened the expression of SHIP-1, a dominant phosphatidylinositol phosphatase regulator of these cells.

CONCLUSIONS

TNF-α provoked the proinflammatory phenotype of B10 and B10pro cells by disturbing SHIP-1 in RA, contributing to the disease development. Reinstating the immunosuppressive property of B10 and B10pro cells might represent novel therapeutic approaches for RA.

Leukocyte Ig-like receptor A3 facilitates inflammation, migration and invasion of synovial tissue-derived fibroblasts via ERK/JNK activation

OBJECTIVE

Leukocyte Ig-like receptor A3 (LILRA3) is a soluble receptor belongs to the immunoglobulin superfamily. Our previous studies demonstrated that LILRA3 is a common genetic risk for multiple autoimmune diseases, including RA. Functional LILRA3 conferred increased risk of joint destruction in patients with early RA. We undertook this study to further investigate the pathological role of LILRA3 in joint inflammation of RA.

METHODS

Soluble LILRA3 was measured by ELISA. LILRA3 plasmids were transfected into human fibroblast-like synoviocytes (FLSs) using electroporation. Activation of extracellular signal-regulated kinase (ERK) and c-Jun N-terminal kinase (JNK) was determined by western blots. Cytokine transcripts were quantified by real-time PCR. Migratory and invasive capacities of FLSs were evaluated using transwell migration and Matrigel invasion assays. FLS apoptosis was analysed using flow cytometry. Colocalization of LILRA3, LILRB1 and HLA-G in RA-FLSs was visualized by immunofluorescence staining.

RESULTS

Soluble LILRA3 was specifically expressed in synovial fluid and serum LILRA3 was significantly increased and positively correlated with disease activity/severity in RA patients. LILRA3 induced an increased expression of IL-6, IL-8 and MMP3 in RA-FLSs. In vitro LILRA3 stimulation or overexpression promoted RA-FLS migration and invasion, and enhanced phosphorylation of ERK/JNK. Inhibition of ERK/JNK resulted in suppression of IL-6/IL-8 expression in LILRA3-stimulated RA-FLSs. LILRA3 was co-localized with its homologue LILRB1 and shared ligand HLA-G in RA-FLSs.

CONCLUSION

The present study provides the first evidence that soluble LILRA3 is a novel proinflammatory mediator involved in synovial inflammation by promoting RA-FLS activation, migration and invasion, probably through the ERK/JNK signalling pathways.

Diminished LAG3+ B cells correlate with exacerbated rheumatoid arthritis

BACKGROUND

Lymphocyte activation gene-3 (LAG3) positive B cells have been identified as a novel regulatory B cell subset, while the role of LAG3+ B cells in the pathogenesis of rheumatoid arthritis (RA) remains elusive.

MATERIALS AND METHODS

Peripheral blood mononuclear cells (PBMCs) from RA, osteoarthritis (OA) patients and healthy volunteers were collected for flow cytometry staining of LAG3+ B cells. Their correlation with RA patient clinical and immunological features were analyzed. Moreover, the frequencies of LAG3+ B cells in collagen-induced arthritis (CIA) mice and naive mice were also detected.

RESULTS

A significant decrease of LAG3+ B cells was observed in RA patients as compared with healthy individuals and OA patients. Notably, the frequencies of LAG3+ B cells were negatively correlated with tender joint count (r = -0.4301, p = .0157) and DAS28-ESR (r = -0.4018, p = .025) in RA patients. In CIA mice, LAG3+ B cell frequencies were also decreased and negatively correlated with the CIA arthritis score.

CONCLUSIONS

Impairment of LAG3+ B cells potentially contributes to RA development. Reconstituting LAG3+ B cells might provide novel therapeutic strategies for the persistent disease.Key messagesLAG3+ B cells have been identified as a novel regulatory B cell subset. However, its role in the pathogenesis of RA remains unknown.This study revealed the decreased frequency of LAG3+ B cells in RA patients. Notably, LAG3+ B cells were negatively correlated with RA disease activity including the tender joint count and DAS28-ESR.In CIA mice, LAG3+ B cell frequencies were also decreased and negatively correlated with the CIA arthritis score.Reconstitution of LAG3+ B cells might provide novel therapeutic strategies for disease perpetuation.

[Association between different treatment timings and adverse neonatal outcomes in pregnant women with syphilis during pregnancy]

Objective: To analyze the association between different treatment timings and adverse neonatal outcomes (premature birth, death, congenital syphilis) in syphilis-infected pregnant women. Methods: The National Management Information System for Prevention of HIV, Syphilis and HBV Mother-to-Child Transmission was used to collect information on the detection and treatment of syphilis-infected pregnant women and their newborns in Guangdong Province from October 2011 to December 2021. According to the gestational weeks of syphilis-infected pregnant women receiving penicillin treatment for the first time, they were divided into four groups: treatment in the first trimester, treatment in the second trimester, treatment in the third trimester, and no treatment during pregnancy. Multivariate logistic regression was used to analyze the association between different treatment timings and adverse neonatal outcomes in syphilis-infected pregnant women. Results: A total of 22 483 syphilis-infected pregnant women were included. The number of pregnant women who started treatment in the first trimester, second trimester, and third trimester and did not receive treatment during pregnancy were 4 549 (20.23%), 8 719 (38.78%), 2 235 (9.94%) and 6 980 (31.05%), respectively. Compared with pregnant women who started treatment in the first trimester, pregnant women who did not receive anti-syphilis treatment during pregnancy had increased risks of neonatal preterm birth (OR=1.42, 95%CI: 1.24-1.62), death (OR=4.27, 95%CI: 1.64-14.69) and congenital syphilis (OR=12.26, 95%CI: 6.35-27.45). At the same time, the risk of congenital syphilis in the newborns of pregnant women who started anti-syphilis treatment in the second trimester (OR=2.68, 95%CI: 1.34-6.16) and third trimester (OR=6.27, 95%CI: 2.99-14.80) also increased. Conclusion: Early initiation of anti-syphilis treatment during pregnancy in patients with syphilis can improve neonatal outcomes.

Impact of shift work on dementia: a systematic review and dose-response meta-analysis

OBJECTIVES

Although shift work has been reported as having a link to dementia, evidence remains inconsistent, and a comprehensive dose-response meta-analysis of the association is still lacking. We therefore conducted this meta-analysis to explore the association between shift work and the risk of dementia.

STUDY DESIGN

Systematic review and dose-response meta-analysis.

METHODS

PubMed, Embase, and Web of Science databases were systematically searched. Fixed or random-effects models were used to estimate the summary relative risks (RRs) and 95% confidence intervals (95% CIs). Generalized least squares regression was used to estimate dose-response associations, and restricted cubic splines were used to examine possible linear or non-linear associations.

RESULTS

Five articles (10 studies) with 72,999 participants and 23,067 cases were eventually included in the meta-analysis. The summary RRs and 95% CIs of dementia risk with shift work and night shift work versus daytime work were 1.13 (95% CI: 1.05-1.21, I2 = 46.70%) and 1.13 (95% CI: 1.03-1.24, I2 = 9.20%), respectively. The risk of dementia increased by 1% (RR = 1.01, 95% CI: 1.01-1.02, I2 = 41.3%) with each 1-year increase in the duration of shift work. We found a non-linear dose-response association between the duration of shift work and the risk of dementia (Pnon-linearity = 0.006). Though the shape of the curve was steeper with the duration of shift work <7 years, the increase was more gradual after 7 years.

CONCLUSION

Our findings suggest that shift work may be a risk factor for future dementia and that controlling the length of shift work is a feasible measure that may contribute to prevent dementia.

Impaired regulatory function of granzyme B-producing B cells against T cell inflammatory responses in lupus mice

OBJECTIVE

Recently, a new subtype of granzyme B (GrB)-producing Breg cells has been identified, which was proven to be involved in autoimmune disease. Our recent report demonstrated that GrB-producing Breg cells were correlated with clinical and immunological features of SLE. However, the effect of GrB-producing Breg cells in lupus mice is unclear.

METHODS

GrB expression in naïve and lupus mouse B cells was analysed using flow cytometry, PCR, ELISA and ELISpot assays. To study the role of GrB-producing B cells in a lupus model, GrB knockout (KO) and wild-type (WT) mice were intraperitoneally injected with monoclonal cells from the mutant mouse strain B6.C-H-2bm12 (bm12) for 2 weeks. In addition, the function of GrB-producing Breg cells in naïve and lupus mice was further explored using in vitro B cells-CD4⁺CD25^- T cell co-culture assays with GrB blockade/KO of B cells.

RESULTS

B cells from the spleens of WT C57BL/6 (B6) mice could express and secret GrB (p<0.001). GrB-producing Breg cells from WT mice showed their regulatory functions on CD4⁺CD25^- T cell. While the frequency of GrB-producing Breg cells was significantly decreased (p=0.001) in lupus mice (p<0.001). Moreover, GrB-producing Breg cells in lupus mice failed to suppress T cell-mediated proinflammatory responses, partially due to the impaired capacity of downregulating the T cell receptor-zeta chain and inducing CD4⁺CD25^- T cell apoptosis.

CONCLUSION

This study further revealed the function and mechanism of GrB-producing Breg cells in regulating T cell homeostasis in lupus mice and highlighted GrB-producing Breg cells as a therapeutic target in SLE.

B cell subsets in adult-onset Still's disease: potential candidates for disease pathogenesis and immunophenotyping

BACKGROUND

Adult-onset Still's disease (AOSD) is a systemic autoinflammatory disorder of unknown etiology. B cells are critical participants in different rheumatic diseases, and their roles in AOSD are rarely investigated. This study aimed to unveil the B cell subset features in AOSD and provide evidence for B cell-based diagnosis and targeted therapies of AOSD.

METHODS

B cell subsets in the peripheral blood of AOSD patients and healthy controls (HCs) were detected by flow cytometry. Firstly, the frequencies of B cell subsets were compared. Then, the correlation analysis was performed to explore the correlation between B cell subsets and clinical manifestations in AOSD. Finally, unbiased hierarchical clustering was performed to divide AOSD patients into three groups with different B cell subset features, and the clinical characteristics of the three groups were compared.

RESULTS

The frequencies of B cell subsets were altered in AOSD patients. Disease-promoting subsets (such as naïve B cells, double negative B cells (DN B cells), and plasmablasts) increased, and potential regulatory subsets (such as unswitched memory B cells (UM B cells) and CD24hiCD27+ B cells (B10 cells)) decreased in the peripheral blood of AOSD patients. In addition, the altered B cell subsets in AOSD correlated with the clinical and immunological features, such as immune cells, coagulation features, and liver enzymes. Intriguingly, AOSD patients could be divided into three groups with distinct B cell immunophenotyping: group 1 (naïve B cells-dominant), group 2 (CD27+ memory B cells-dominant), and group 3 (precursors of autoantibody-producing plasma cells-dominant). Moreover, these three group patients demonstrated differential manifestations, including immune cells, liver or myocardial enzymes, coagulation features, and systemic score.

CONCLUSIONS

B cell subsets are significantly altered in AOSD patients, potentially contributing to the disease pathogenesis. These findings would inspire B cell-based diagnosis and targeted therapies for this refractory disease.

Raman spectroscopy as a promising diagnostic method for rheumatoid arthritis

Background: Diagnosis of rheumatoid arthritis (RA) basically relies on clinical symptoms and autoantibodies, especially anti-citrullinated protein antibodies (ACPAs) and rheumatoid factor (RF). However, the lack of autoantibodies is still a dilemma clinically in seronegative RA, especially in the early stage of the disease. This study aimed to provide a unique disease fingerprint with high diagnostic value to discriminate RA based on Raman spectroscopy. Methods: Raman spectroscopy provides a repertoire of biomolecules in serum from RA. Multivariate dimension-reducing methods and machine-learning algorithms were exploited to reveal the intrinsic differences and the potential discrimination power. The underlying differential biomolecules were retrieved by the assignment of Raman peaks. Moreover, the correlations between the spectral differences and RA patient's clinical and immunological manifestations were also analyzed. Results: RA patients exhibited unique Raman spectra characterized by biomolecular alterations during the disease progression. The discrimination power yielded 97.3% sensitivity and 94.8% specificity for RA diagnosis. In the recognition of ACPA-negative RA, the sensitivity and specificity also reached 95.6% and 92.8%, respectively. In particular, the differential Raman spectrum peaks of RA patients mainly represented lipids, amino acids, glycogen, and fatty acids. Further analysis showed that the different serum Raman spectra correlated with the clinical features of RA, including disease duration, RF, anticyclic citrullinated peptide antibodies (anti-CCPs), IgA, IgM, IgG, tender joint count, and swollen joint count (|rs| = 0.15-0.52, p < 0.05). Conclusions: Raman spectroscopy was revealed to be a promising diagnostic method for RA, especially for ACPA-negative patients.

Decreased natural killer T-like cells correlated to disease activity in systemic lupus erythematosus

OBJECTIVES

To evaluate the absolute numbers and frequencies of natural killer T-like (NKT-like) cells in systemic lupus erythematosus (SLE) and to characterize the possible role of the cells.

METHODS

Seventy-nine patients with SLE together with 30 age- and sex-matched healthy controls were enrolled. Flow cytometric determination of peripheral NKT-like cells was carried out for all participants by detecting the absolute counts (Abs) and percentage (%) of CD3 + CD16 + CD56 + cells. Disease activity index, laboratory parameters, and clinical manifestations were collected. The correlation between the cells and these parameters was analyzed.

RESULTS

SLE patients had, with respect to controls, considerably decreased values of NKT-like cells (P < 0.001 in both absolute number and percentage). The absolute number of NKT-like cells was found to have positive correlations with WBC, RBC, PLT, C3, C4, IgM and negative correlations with the disease duration, SLEDAI-2 K, anti-dsDNA, anti-nucleosome, anti-ribosomal protein, CRP, ESR. Meanwhile, it was found that the percentage values of NKT-like cells decreased in SLE patients with nephritis which was correlated with anti-ribosomal protein and CRP in comparison to SLE patients without nephritis. Moreover, an increase in the NKT-like cell counts was also observed in the patients with a clinical response to the treatment.

CONCLUSIONS

The absolute counts and frequencies of NKT-like cells decreased in SLE patients significantly, which correlated to disease activities and could recover to normal after the treatment. The NKT-like cells may play an important role in the pathogenesis of SLE and could be a useful marker in the disease assessment. Key Points • The absolute counts and frequencies of NKT-like cells decreased in SLE patients significantly. • NKT-like cells were related to the disease activities and could restore after the treatment. • NKT-like cells may be a useful marker in the disease assessment.

Soluble CD24 is an inflammatory biomarker in early and seronegative rheumatoid arthritis

Introduction: Rheumatoid arthritis (RA) is a chronic, systemic autoimmune disease characterized by autoantibody production, joint inflammation and bone destruction. Nearly 1/3 of RA patients with the active disease also exhibit a normal range of ESR and CRP. Here we assessed the performance and clinical significance of soluble CD24 (sCD24) as a biomarker of disease activity in RA.Methods: A total of 269 RA patients, 59 primary Sjogren's syndrome (SS) patients, 81 systematic lupus erythematosus (SLE) patients, 76 osteoarthritis (OA) patients and 97 healthy individuals (HC) were included in this study. Soluble CD24 in sera were detected by ELISA. Therefore, the concentration of sCD24 was analyzed in RA patients with different disease activity statuses.Results: The sCD24 was significantly increased in RA (2970 pg/mL), compared to other rheumatic diseases (380-520 pg/mL) and healthy individuals (320 pg/mL). Moreover, sCD24 was elevated in 66.67% of early RA and 61.11% of seronegative RA patients. In addition, sCD24 was significantly correlated with the disease duration and inflammatory indicators.Conclusion: The sCD24 could be an inflammatory biomarker in RA patients, especially in early and seronegative patients.

Efficacy and Safety of Low-Dose Interleukin 2 for Primary Sjögren Syndrome: A Randomized Clinical Trial

IMPORTANCE

Primary Sjögren syndrome (pSS) is a systemic autoimmune disease associated with dysregulated immune cells, with no efficient therapy. There is a need to study potential therapeutic approaches.

OBJECTIVE

To investigate the efficacy, safety, and immune response of low-dose interleukin 2 (LD-IL-2) in the treatment of pSS.

DESIGN, SETTING, AND PARTICIPANTS

A double-blind, placebo-controlled randomized clinical trial was conducted with a 2-group superiority design from June 2015 to August 2017. Sixty patients, aged 18 to 70 years, were recruited from Peking University People's Hospital. Efficacy analyses were based on the intention-to-treat (ITT) principle. Data were analyzed from December 2018 to March 2020.

INTERVENTIONS

Patients with pSS were treated with LD-IL-2 or placebo for 12 weeks and accompanied by 12 weeks of follow-up.

MAIN OUTCOMES AND MEASURES

The primary end point was defined as a 3-point or greater improvement on the European League Against Rheumatism Sjögren's Syndrome Disease Activity Index (ESSDAI) by week 24. The secondary end points included other clinical responses, safety, and changes of immune cell subsets at week 12 and 24.

RESULTS

Sixty patients with pSS were recruited, with 30 in the LD-IL-2 group (mean [SD] age, 47.6 [12.8] years; 30 [100%] women) and 30 in the placebo group (mean [SD] age, 51.0 [11.9] years; 30 [100%] women), and 57 completed the trial. More patients in the LD-IL-2 group (20 [66.7%]) achieved ESSDAI score reduction of at least 3 points than in the placebo group (8 [26.7%]) at week 24 (P = .004). There were greater resolutions of dryness, pain, and fatigue in the LD-IL-2 group than placebo group at week 12 (dryness: difference, -18.33 points; 95% CI, -28.46 to -8.21 points; P = .001; pain: difference, -10.33 points; 95% CI, -19.38 to -1.29 points; P = .03; fatigue: difference, -11.67 points; 95% CI, -20.65 to -2.68 points; P = .01). No severe adverse events were observed in either group. In addition, the LD-IL-2 group showed a significant decrease in infection compared with the placebo group (1 [3.3%] vs 9 [30.0%]; P = .006). Immunological analysis revealed that LD-IL-2 promoted an expansion of regulatory T cells and regulatory CD24highCD27+ B cells.

CONCLUSIONS AND RELEVANCE

In this randomized clinical trial, LD-IL-2 was effective and well tolerated in patients with pSS, and it restored immune balance, with enhanced regulatory T cells and CD24highCD27+ B cells.

TRIAL REGISTRATION

ClinicalTrials.gov Identifier: NCT02464319.

Andrographolide restored production performances and serum biochemical indexes and attenuated organs damage in Mycoplasma gallisepticum-infected broilers

1. This study aimed to study the preventive and therapeutic effects of andrographolide (Andro) during Mycoplasma gallisepticum HS strain (MG) infection in ArborAcres (AA) broilers.2. The minimum inhibitory concentration (MIC) of Andro against MG was measured. Broiler body weight, feed efficiency, morbidity, cure rate and mortality were recorded during the experiment. Air sac lesion scores and immune organ index were calculated. Expression of pMGA1.2 in lung tissue and serum biochemical indices were examined. Histopathological examinations of immune organs, liver, trachea and lung tissue were conducted by Haematoxylin and Eosin stain.3. MIC was 3.75 μg/mL and Andro significantly inhibited the expression of pMGA1.2 (P ≤ 0.05). Compared with control MG-infected group, Andro low-dose and high-dose prevention reduced the morbidity of chronic respiratory disease in 40.00% and 50.00%, respectively. Mortality of C, D and E group was 16.67%, 10.00% and 6.67%, respectively. Cure rate of E, F, G and H group was 92.00%, 92.86%, 93.33% and 100.0%, respectively. Compared with control MG-infected group, Andro treatment significantly increased average weight gain (AWG), relative weight gain rate (RWG) and feed conversion rate (FCR) at 18 to 24 days (P ≤ 0.05). Compared with control group, Andro alone treatment significantly increased AWG in broilers (P ≤ 0.05).4. Compared with control MG-infected group, Andro significantly attenuated MG-induced air sac lesion, immune organs, liver, trachea and lung damage in broilers. Andro alone treatment did not induce abnormal morphological changes in these organs in healthy broilers. Serum biochemical analysis results showed, comparing with control MG-infected group, Andro significantly decreased the content of total protein, albumin, globulin, alanine aminotransferase, aspartate aminotransferase, total bilirubin, urea, creatinine, uric acid, total cholesterol, and increased the albumin/globulin ratio and content of alkaline phosphatase, apolipoprotein B and apolipoprotein A-I in a dose-dependent manner (P ≤ 0.05).5. Andro could act as a potential agent against MG infection in broilers.

Tonsillar Microbiome-Derived Lantibiotics Induce Structural Changes of IL-6 and IL-21 Receptors and Modulate Host Immunity

Emerging evidence emphasizes the functional impacts of host microbiome on the etiopathogenesis of autoimmune diseases, including rheumatoid arthritis (RA). However, there are limited mechanistic insights into the contribution of microbial biomolecules especially microbial peptides toward modulating immune homeostasis. Here, by mining the metagenomics data of tonsillar microbiome, a deficiency of the encoding genes of lantibiotic peptides salivaricins in RA patients is identified, which shows strong correlation with circulating immune cells. Evidence is provided that the salivaricins exert immunomodulatory effects in inhibiting T follicular helper (Tfh) cell differentiation and interleukin-21 (IL-21) production. Mechanically, salivaricins directly bind to and induce conformational changes of IL-6 and IL-21 receptors, thereby inhibiting the bindings of IL-6 and IL-21 to their receptors and suppressing the downstream signaling pathway. Finally, salivaricin administration exerts both prophylactic and therapeutic effects against experimental arthritis in a murine model of RA. Together, these results provide a mechanism link of microbial peptides-mediated immunomodulation.

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.

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.

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.

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.

CD14+CD16- monocytes are the main precursors of osteoclasts in rheumatoid arthritis via expressing Tyro3TK

Background

Monocytes as precursors of osteoclasts in rheumatoid arthritis (RA) are well demonstrated, while monocyte subsets in osteoclast formation are still controversial. Tyro3 tyrosine kinase (Tyro3TK) is a member of the receptor tyrosine kinase family involved in immune homeostasis, the role of which in osteoclast differentiation was reported recently. This study aimed to compare the osteoclastic capacity of CD14⁺CD16⁺ and CD14⁺CD16⁻ monocytes in RA and determine the potential involvement of Tyro3TK in their osteoclastogenesis.

Methods

Osteoclasts were induced from CD14⁺CD16⁺ and CD14⁺CD16⁻ monocyte subsets isolated from healthy control (HC) and RA patients in vitro and evaluated by tartrate-resistant acid phosphatase (TRAP) staining. Then, the expression of Tyro3TK on CD14⁺CD16⁺ and CD14⁺CD16⁻ monocyte subsets in the peripheral blood of RA, osteoarthritis (OA) patients, and HC were evaluated by flow cytometry and qPCR, and their correlation with RA patient clinical and immunological features was analyzed. The role of Tyro3TK in CD14⁺CD16⁻ monocyte-mediated osteoclastogenesis was further investigated by osteoclast differentiation assay with Tyro3TK blockade.

Results

The results revealed that CD14⁺CD16⁻ monocytes were the primary source of osteoclasts. Compared with HC and OA patients, the expression of Tyro3TK on CD14⁺CD16⁻ monocytes in RA patients was significantly upregulated and positively correlated with the disease manifestations, such as IgM level, tender joint count, and the disease activity score. Moreover, anti-Tyro3TK antibody could inhibit Gas6-mediated osteoclast differentiation from CD14⁺CD16⁻ monocytes in a dose-dependent manner.

Conclusions

These findings indicate that elevated Tyro3TK on CD14⁺CD16⁻ monocytes serves as a critical signal for osteoclast differentiation in RA.

Self-Assembling Glycopeptide Conjugate as a Versatile Platform for Mimicking Complex Polysaccharides

Polysaccharides are a class of carbohydrates that play pivotal roles in living systems such as being chemical messengers in many vital biological pathways. However, the complexity and heterogeneity of these natural structures have posed daunting challenges on their production, characterization, evaluation, and applications. While there have been various types of synthetic skeletons that could mimic some biological aspects of polysaccharides, a safer and more easily accessed system is still desired to avoid the unnatural components and difficulties in modifying the structures. In this work, conveniently accessible self-assembling glycopeptide conjugates are developed, where the natural O-glycosidic linkages and phosphoryl modifications assist the self-assembly and concurrently reduce the risk of toxicity. The generated nanoparticles in aqueous solution offer a multivalent display of structurally controllable carbohydrates as mimics of polysaccharides, among which a mannosylated version exhibits immunostimulatory effects in both cellular assays and vaccination of mice. The obtained results demonstrate the potential of this glycopeptide conjugate-derived platform in exploiting the intriguing properties of carbohydrates in a more structurally maneuverable fashion.

Fine structure of the human retina defined by confocal microscopic immunohistochemistry

INTRODUCTION

Research in to the pathophysiology of the complex layers of retinal and sub-retinal cells is hampered by inadequate recognition of particular cells and tissues. A comprehensive panel of antibodies recognising retinal tissues is lacking. Our purpose was to determine the value of a panel of antibodies labelling various cells in the human retina.

METHOD

Five groups of antibodies labelled frozen sections of retinas: (1) protein kinase C-α, Glutamine Synthetase (GS) and ionized calcium-binding adapter molecule 1 (Iba1); (2) Parvalbumin, Calretinin and glial fibrillary acidic protein (GFAP); (3) Thy1, GS and Iba1; (4) Rhodopsin, GS and Iba1; and (5) Brn3a, Rhodopsin and protein kinase C-α. The distribution of these antigens were determined by confocal microscopy and calculated grey value of each antibody in each layer of the retina by Image J.

RESULTS

Different antibodies determined certain retinal layers. Thy 1 is a good determinant of the ganglion cell layer, whilst GS is present in all layers except the photoreceptor layer. Brn3a is specific for the ganglion cell layer whilst parvalbumin marks the ganglion cell layer and the outer plexiform layer. Rhodopsin strongly marks the photoreceptor layer, but this is also marked weakly by GFAP.

CONCLUSION

The multiple labelling of human retinal cells brings further understanding of the biological characteristics and functions of these cells, and provides a theoretical basis for their possible role in diseases. In the growing field of human retina research, our data may provide a point of reference for future studies of the human retina.

LAG3 (CD223) and autoimmunity: Emerging evidence

Immune checkpoint molecules play pivotal roles in maintaining the immune homeostasis. Targeting these molecules, such as the classical Cytotoxic T-Lymphocyte Antigen 4 (CTLA4) and Programmed Cell Death Protein 1 (PD1), achieves great success in treating cancers. However, not all the patients respond well. This urges the immunologists to identify novel immune checkpoint molecules. Lymphocyte activation gene-3 (LAG3; CD223) is a newly identified inhibitory receptor. It is expressed on a variety of immune cells, including CD4⁺ T cells, CD8⁺ T cells, Tregs, B cells, and NK cells. Its unique intracellular domains, signaling patterns as well as the striking synergy observed in its targeted therapy with anti-PD1 indicate the important role of LAG3 in maintaining immune tolerance. Currently, a variety of agents targeting LAG3 are in clinical trials, revealing great perspectives in the future immunotherapy. In this review, we briefly summarize the studies on LAG3, including its structure, isoforms, ligands, signaling, function, roles in multiple diseases, as well as the latest targeted therapeutic advances, with particular concern on the potential association of LAG3 with autoimmune diseases.

Seroprevalence of Toxoplasma gondii infection in people in southeast Hubei province, China

Toxoplasma gondii is a world-widely spread zoonotic parasite. However, scarce knowledge is known about the prevalence of T. gondii infection in people in Hubei province, China. This study herein was to perform epidemiological investigation of T. gondii infection in people in this region. A total 12527 blood samples were obtained during 2015-2018, and were assayed for T. gondii antibodies of IgG and IgM, respectively by employing an indirect hemagglutination test (IHA). The results discovered that the prevalence of T. gondii in people was 2.44% and 6.1%, respectively based on antibodies of IgG and IgM, respectively. The prevalence was ranged from 0.3% to 5.4% during 2015-2018 based on IgM antibodies. For genders, the prevalence was 0.7% and 2.6% in males and females, respectively based on IgM antibodies. In different years, the prevalence was ranged from 4.9% to 14.0% based on IgG antibodies. The prevalence of T. gondii was 4.9% and 6.6% in males and femalesy based on IgG antibodies. The current results may be helpful for the implementation of preventive measures against Toxoplasma infection among people living in this region.

Scavenger receptor-A is a biomarker and effector of rheumatoid arthritis: A large-scale multicenter study

Early diagnosis is critical to improve outcomes in rheumatoid arthritis (RA), but current diagnostic tools have limited sensitivity. Here we report a large-scale multicenter study involving training and validation cohorts of 3,262 participants. We show that serum levels of soluble scavenger receptor-A (sSR-A) are increased in patients with RA and correlate positively with clinical and immunological features of the disease. This discriminatory capacity of sSR-A is clinically valuable and complements the diagnosis for early stage and seronegative RA. sSR-A also has 15.97% prevalence in undifferentiated arthritis patients. Furthermore, administration of SR-A accelerates the onset of experimental arthritis in mice, whereas inhibition of SR-A ameliorates the disease pathogenesis. Together, these data identify sSR-A as a potential biomarker in diagnosis of RA, and targeting SR-A might be a therapeutic strategy.