Vulnerability of atherosclerotic plaques is associated with type I interferon in a murine model of lupus and atherosclerosis

Expression and Significance of Programmed Death-1 and Its Ligands in the Accelerated Formation of Atherosclerosis in an Induced Murine Lupus Model

Atherosclerosis (AS) is a chronic inflammatory disease that occurs in artery walls, which seriously affects the survival and prognosis of patients with systemic lupus erythematosus (SLE). Immune and inflammatory responses have notable effects on all stages of AS. In this study, we modeled SLE combined with AS in vivo via intraperitoneal injection of pristane (2,6,10,14-tetramethylpentadecane) into apolipoprotein E-knockout (ApoE−/−) mice that had accelerated atherosclerotic lesions compared with wild-type (WT) ApoE−/− mice. In pristane-induced ApoE−/− mice, expression of programmed death-1 (PD-1) and programmed death-ligand 1 (PD-L1) in peripheral blood and on the surfaces of atherosclerotic lesions significantly increased, and levels of proinflammatory cytokines, namely, interferon-gamma (IFN-γ) and tumor necrosis factor alpha (TNF-α) in peripheral blood were elevated. We did not detect expression of programmed death-ligand 2 (PD-L2) in the arterial plaques of either pristane-induced or WT ApoE−/− mice, nor did we observe any significant difference in PD-L2 expression in peripheral blood between the two groups. Taken together, these results suggested that PD-1/PD-L1 signaling pathway might play an important regulatory role in the progression of AS in an induced murine lupus model which implies a potential target for treatment of AS in SLE.

circ_0086296 induced atherosclerotic lesions via the IFIT1/STAT1 feedback loop by sponging miR-576-3p

Extensive inflammation of endothelial cells (ECs) facilitates atherosclerotic lesion formation. Circular RNA (circRNA) participates in atherosclerosis (AS)-related inflammation responses; however, whether and how circ_0086296 regulates atherosclerotic inflammation and lesions have not been investigated. Microarray analysis, quantitative real-time polymerase chain reaction, and fluorescence in situ hybridization assay were performed to detect the expression and location of hsa_circ_0086296 in human carotid artery plaques, aorta of atherosclerotic mice, and human umbilical vein endothelial cells (HUVECs). Sanger sequencing was used to verify the loop structure of circ_0086296. The relationship among circ_0086296, miR-576-3p, IFIT1, STAT1, and EIF4A3 was validated using bioinformatics, luciferase assay, RNA pull-down assay, and RNA immunoprecipitation. The atherosclerosis mouse model was used to evaluate the function of circ_0086296 in vivo. circ_0086296 expression was significantly upregulated in human carotid artery plaques, oxidized low-density lipoprotein (ox-LDL)-treated HUVECs, and the aorta of atherosclerotic mice. Functional analysis indicated that circ_0086296 promotes ECs injury in vitro and atherosclerosis progression in vivo. The mechanism analysis indicated that circ_0086296 sponged miR-576-3p to promote IFIT1–STAT1 expression. Moreover, STAT1 upregulated circ_0086296 expression, forming the circ_0086296/miR-576-3p/IFIT1/STAT1 feedback loop. Notably, inhibition of the circ_0086296/miR-576-3p/IFIT1 axis could block atherosclerotic lesion formation both in vivo and in vitro. Finally, circ_0086296 was overexpressed in exosomes of patients with atherosclerosis and exosomes of ox-LDL-treated ECs. Therefore, the circ_0086296/miR-576-3p/IFIT1/STAT1 feedback loop participates in atherosclerosis progression and contributes to the high circ_0086296 expression observed in the exosomes of serum of patients with atherosclerosis. This study sought to provide a deep understanding of the mechanisms underlying the aberrant EC phenotype in AS.

A pro-inflammatory and fibrous cap thinning transcriptome profile accompanies carotid plaque rupture leading to stroke

Atherosclerotic plaque rupture is the etiology of ischemic stroke and myocardial infarction. The molecular mechanisms responsible for rupture remain unclear, in part, due to the lack of data from plaques at the time of rupture. Ribosome-depleted total RNA was sequenced from carotid plaques obtained from patients undergoing carotid endarterectomy with high-grade stenosis and either (1) a carotid-related ischemic cerebrovascular event within the previous 5 days ('recently ruptured,' n = 6) or (2) an absence of a cerebrovascular event ('asymptomatic,' n = 5). Principal component analysis confirmed plaque rupture was responsible for the greatest percentage of the variability between samples (23.2%), and recently ruptured plaques were enriched for transcripts associated with inflammation and extracellular matrix degradation. Hierarchical clustering achieved differentiation of the asymptomatic from the recently ruptured plaques. This analysis also found co-expression of transcripts for immunoglobulins and B lymphocyte function, matrix metalloproteinases, and interferon response genes. Examination of the differentially expressed genes supported the importance of inflammation and inhibition of proliferation and migration coupled with an increase in apoptosis. Thus, the transcriptome of recently ruptured plaques is enriched with transcripts associated with inflammation and fibrous cap thinning and support further examination of the role of B lymphocytes and interferons in atherosclerotic plaque rupture.

Mesenchymal stem cell transplantation alleviated atherosclerosis in systemic lupus erythematosus through reducing MDSCs

Objective

The mechanism by which mesenchymal stem cell (MSC) transplantation alleviates atherosclerosis in systemic lupus erythematosus (SLE) remains elusive. In this study, we aim to explore the efficacy and mechanism of MSC in ameliorating atherosclerosis in SLE.

Methods

ApoE^−/− and Fas^−/− mice on the B6 background were cross-bred to generate SLE mice with atherosclerosis. Myeloid-derived suppressor cells (MDSCs) were sorted and quantified. The apoE^−/−Fas^−/− mice were either treated with anti-Gr antibody or injected with MDSCs. The lupus-like autoimmunity and atherosclerotic lesions were evaluated. Furthermore, the apoE^−/−Fas^−/− mice were transplanted with MSCs and lupus-like autoimmunity and atherosclerotic lesions were assessed.

Results

MDSCs in peripheral blood, spleen, draining lymph nodes increased in apoE^−/−Fas^−/− mice compared with B6 mice. Moreover, the adoptive transfer of MDSCs aggravated both atherosclerosis and SLE pathologies, whereas depleting MDSCs ameliorated those pathologies in apoE^−/−Fas^−/− mice. MSC transplantation in apoE^−/−Fas^−/− mice decreased the percentage of MDSCs, alleviated the typical atherosclerotic lesions, including atherosclerotic lesions in aortae and liver, and reduced serum cholesterol, triglyceride and low-density lipoprotein levels. MSC transplantation also reduced SLE pathologies, including splenomegaly, glomerular lesions, anti-dsDNA antibody in serum, urine protein and serum creatinine. Moreover, MSC transplantation regulated the generation and function of MDSCs through secreting prostaglandin E 2 (PGE2).

Conclusion

Taken together, these results indicated that the increased MDSCs contributed to atherosclerosis in SLE. MSC transplantation ameliorated the atherosclerosis and SLE through reducing MDSCs by secreting PGE2.

Graphical Abstract

Supplementary Information

The online version contains supplementary material available at 10.1186/s13287-022-03002-y.

Endothelial Dysfunction in Systemic Lupus Erythematosus and Systemic Sclerosis: A Common Trigger for Different Microvascular Diseases

This review describes the complex interplay between inflammation, vasculopathy and fibrosis that involve the heart and peripheral small vessels, leading to endothelial stiffness, vascular damage, and early aging in patients with systemic lupus erythematosus and systemic sclerosis, which represents two different models of vascular dysfunction among systemic autoimmune diseases. In fact, despite the fact that diagnostic methods and therapies have been significantly improved in the last years, affected patients show an excess of cardiovascular mortality if compared with the general population. In addition, we provide a complete overview on the new techniques which are used for the evaluation of endothelial dysfunction in a preclinical phase, which could represent a new approach in the assessment of cardiovascular risk in these patients.

Assessment and management of the heightened risk for atherosclerotic cardiovascular events in patients with lupus erythematosus or dermatomyositis

For patients with lupus erythematosus (LE) or dermatomyositis (DM), there is an urgent need to address a heightened risk of clinical events, chiefly heart attacks and strokes, caused by atherosclerotic cardiovascular disease (ASCVD). Patients with LE or DM frequently exhibit high levels of conventional risk factors for ASCVD events, particularly dyslipoproteinemia and hypertension; an amplified burden of atherosclerotic plaques; and increased age- and sex-adjusted rates of ASCVD events compared with the general population. The rate of ASCVD events exceeds what would be expected from conventional risk factors, suggesting that disease-specific autoimmune processes exacerbate specific, known pathogenic steps in atherosclerosis. Importantly, despite their heightened risk, patients with LE or DM are often undertreated for known causative agents and exacerbators of ASCVD. Herein, we propose an approach to assess and manage the heightened risk of ASCVD events in patients with LE or DM. Our approach is modeled in large part on established approaches to patients with diabetes mellitus or stage 3 or 4 chronic kidney disease, which are well-studied conditions that also show heightened risk for ASCVD events and have been explicitly incorporated into standard clinical guidelines for ASCVD. Based on the available evidence, we conclude that patients with LE or DM require earlier and more aggressive screening and management of ASCVD. We suggest that physicians consider implementing multipliers of conventional risk calculators to trigger earlier initiation of lifestyle modifications and medical therapies in primary prevention of ASCVD events, employ vascular imaging to quantify the burden of subclinical plaques, and treat to lower lipid targets using statins and newer therapies, such as PCSK9 inhibitors, that decrease ASCVD events in nonautoimmune cohorts. More clinical vigilance is needed regarding surveillance, prevention, risk modification, and treatment of dyslipidemias, hypertension, and smoking in patients with LE or DM. All of these goals are achievable.

Endothelial cell senescence: A machine learning-based meta-analysis of transcriptomic studies

Numerous systemic vascular dysfunction that leads to age-related diseases is highly associated with endothelial cell (EC) senescence; thus, identifying consensus features of EC senescence is crucial in understanding the mechanisms and identifying potential therapeutic targets. Here, by utilizing a total of 8 screened studies from different origins of ECs, we have successfully obtained common features in both gene and pathway level via sophisticated machine learning algorithms. A total of 400 differentially expressed genes (DEGs) were newly discovered with meta-analysis when compared to the usage of individual studies. The generated parsimonious model established 36 genes and 57 pathways features with non-zero coefficient, suggesting remarkable association of phosphoglycerate dehydrogenase and serine biosynthesis pathway with endothelial cellular senescence. For the cross-validation process to measure model performance of 36 deduced features, leave-one-study-out cross-validation (LOSOCV) was employed, resulting in an overall area under the receiver operating characteristic (AUROC) of 0.983 (95 % CI, 0.952, 1.000) showing excellent discriminative performance. Moreover, pathway-level analysis was performed by Pathifier algorithm, obtaining a total of 698 pathway deregulation scores from the 10,416 merged genes. In this process, high dimensional data was eventually narrowed down to 57 core pathways with AUROC value of 0.982 (95 % CI, 0.945, 1.000). The robust model with high performance underscores the merit of utilizing sophisticated meta-analysis in finding consensus features of endothelial cell senescence, which may lead to the development of therapeutic targets and advanced understanding of vascular dysfunction pathogenesis with further elucidation.

IFN-I Mediates Dysfunction of Endothelial Progenitor Cells in Atherosclerosis of Systemic Lupus Erythematosus

Systemic lupus erythematosus (SLE) is a multi-system autoimmune disease including the cardiovascular system. Atherosclerosis is the most common cardiovascular complication of SLE and a significant risk factor for morbidity and mortality. Vascular damage/protection mechanism in SLE patients is out of balance, caused by the cascade reaction among oxidative stress, proinflammatory cytokines, Neutrophil Extracellular Traps, activation of B cells and autoantibodies and abnormal T cells. As a precursor cell repairing vascular endothelium, endothelial progenitor cells (EPCs) belong to the protective mechanism and show the reduced number and impaired function in SLE. However, the pathological mechanism of EPCs dysfunction in SLE remains ill-defined. This paper reviews the latest SLE epidemiology and pathogenesis, discusses the changes in the number and function of EPCs in SLE, expounds the role of EPCs in SLE atherosclerosis, and provides new guidance and theoretical basis for exploring novel targets for SLE treatment.

Systemic lupus erythematosus aggravates atherosclerosis by promoting IgG deposition and inflammatory cell imbalance

Background

Systemic lupus erythematosus (SLE) patients experience a premature and more severe presentation of coronary artery disease. The underlying mechanisms of accelerated coronary artery disease in SLE patients remain to be elucidated.

Methods

By using atherosclerosis combining a SLE murine model, we proved that the onset of SLE aggravates atherosclerosis. Although the onset of SLE reduced blood lipids slightly, immune deviation contributed to aggravated atherosclerosis in lupus mice. Lupus atheroma were characterized by inflammatory cell infiltration, such as gathered dendritic cells, macrophages, and IgG deposition.

Results

Decreased lymphocytes and magnified dendritic cells in the spleen were also observed in lupus mice. Hydroxychloroquine prevented atherosclerosis progression mainly by reversing immune status abnormality caused by SLE. Serum interferon alfa levels were not changed in lupus mice.

Conclusion

These findings strongly suggested that anti-inflammatory therapies and hydroxychloroquine provide a new possible strategy for treating SLE patients with atherosclerosis.

Interferon-stimulated gene 15 expression in systemic lupus erythematosus : Diagnostic value and association with lymphocytopenia

BACKGROUND

The aim of this study was to (a) assess the relationship between interferon-stimulated gene 15 (ISG15) expression and clinical manifestations of systemic lupus erythematosus (SLE) and (b) investigate the diagnostic value of ISG15 in SLE.

PATIENTS AND METHODS

The study comprised 28 patients newly diagnosed with SLE, 10 patients with undifferentiated connective tissue disease, and 22 healthy volunteers. Of the SLE patients, 14 were chosen randomly to be followed up for 4 weeks. ISG15 expression in whole blood cells was determined by quantitative polymerase chain reaction. Clinical and laboratory parameters were recorded at baseline and after treatment.

RESULTS

The ISG15 mRNA level was higher in whole blood cell counts of SLE patients when compared with the disease control and healthy control groups. Moreover, it was correlated with SLE disease activity as assessed via the SLE disease activity index, serositis, and anemia at baseline. ISG15 expression correlated with lymphocytopenia in active SLE patients before treatment. On receiver operating characteristic curve analysis, the area under the curve for ISG15 expression was 0.826 (p = 0.000015).

CONCLUSION

ISG15 expression is relatively high in SLE patients and correlates with disease activity before treatment. ISG15 expression is higher in SLE patients with lymphocytopenia before treatment.

Endothelial cell injury is involved in atherosclerosis and lupus symptoms in gld.apoE- / - mice

AIM

Cardiovascular complications related to atherosclerosis are major causes of morbidity and mortality in patients with systemic lupus erythematosus (SLE). However, the underlying mechanisms are not fully understood. Endothelial dysfunction has been identified as having involvement in pathogenesis of cardiovascular diseases and SLE. This study aims to evaluate endothelial cell injury in mice with the combination of lupus and atherosclerosis.

METHODS

The mouse model of accelerated atherosclerosis in lupus (gld.apoE^{- / -} mouse) was generated from apolipoprotein E-deficient (apoE^{- / -} ) and Fasl^gld C57BL/6 mice. The lupus-like autoimmunity and atherosclerotic lesions were evaluated. The endothelial cell injury was determined.

RESULTS

The results showed that the double-mutant gld.apoE^{- / -} mice were generated. Spleens from 5-month-old gld.apoE^{- / -} mice were significantly enlarged compared with wild-type mice (WT mice). The gld.apoE^{- / -} mice produced high levels of total immunoglobulin G (IgG) and IgM and showed marked increase of IgG and C3 deposits in the glomeruli. The gld.apoE^{- / -} mice displayed a pattern of glomerulonephritis typically found in SLE. The gld.apoE^{- / -} mice have high levels of serum creatinine. The total cholesterol, low-density lipoprotein cholesterol and triglycerides were significantly increased, while high-density lipoprotein cholesterol decreased in the double-mutant mice. The circulating endothelial progenitor cells were significantly decreased. The serum levels of thrombomodulin and vascular cell adhesion molecule-1 were significantly elevated in gld.apoE^{- / -} mice. The gld.apoE^{- / -} mice simultaneously exhibited SLE and atherosclerosis characteristics.

CONCLUSION

Our findings indicated that endothelial cell injury might be a biomarker for evaluating risks of cardiovascular disease in SLE and targeting endothelial cell dysfunction might prevent and treat atherosclerosis in SLE.

Systemic Inflammatory Response and Atherosclerosis: The Paradigm of Chronic Inflammatory Rheumatic Diseases

Patients with Chronic Inflammatory Rheumatic diseases (CIRD) are at increased risk of cardiovascular disease (CVD), ascribed not only to classical risk factors, but also to the presence of chronic systemic inflammatory response. Αtherosclerosis, the cornerstone of CVD, is known to be accelerated in CIRD; rheumatoid arthritis promotes atheromatosis and associates with preclinical atherosclerosis equivalent to Diabetes Mellitus, which also seems to apply for systemic lupus erythematosus. Data on ankylosing spondylitis and psoriatic arthritis, albeit more limited, also support an increased CV risk in these patients. The association between inflammation and atherosclerosis, has been thoroughly investigated in the last three decades and the role of inflammation in the pathogenesis and progression of atherogenesis has been well established. Endothelial dysfunction, oxidative stress in vascular endothelial cells and macrophage accumulation, toll-like receptor signaling, NLPR-3 formation and subsequent pro-inflammatory cytokine production, such as TNFa, IL-1β, IL-6, and TNF-like cytokine 1A, are few of the mechanisms implicated in the atherogenic process. Moreover, there is evidence that anti-inflammatory biologic drugs, such as anti-TNF and anti-IL1β agents, can decelerate the atherogenic process, thus setting new therapeutic targets for early and effective disease control and suppression of inflammation, in addition to aggressive management of classical CV risk factors.