Imbalanced gp130 signalling in ApoE-deficient mice protects against atherosclerosis

The role of interleukin-6 trans-signalling on cardiovascular dysfunction in inflammatory arthritis

Objectives

Cardiovascular (CV) mortality in RA patients is 50% higher than in the general population. There is increasing recognition that systemic inflammation is a major driver of this. IL-6 is implicated in cardiovascular disease (CVD) in the general population but its role in CVD in RA is undefined. Of the two modes of IL-6 signalling, trans-signalling is pro-inflammatory whereas classical signalling is linked with inflammation resolution. This study examines the role of IL-6 trans-signalling in CVD in a mouse model and patients with RA.

Methods

Myography determined the effect of IL-6 trans-signalling blockade, using sgp130Fc, on aortic constriction in murine collagen-induced arthritis. Serum CCL2 and sVCAM-1 as soluble biomarkers of sIL-6R trans-signalling were investigated in a human cross-sectional study. An observational longitudinal study investigated the association between these biomarkers and progression of subclinical atherosclerosis in early RA by measuring carotid intima-media thickness (CIMT).

Results

sgp130Fc reduced arthritis severity, serum CCL2 and sVCAM-1 and restored vascular function in collagen-induced arthritis (CIA). In established RA, sVCAM-1 correlated with the 28-joint DAS (DAS28) and CV risk. In early RA, baseline DAS28 was associated with CIMT change at 6 months. CIMT ‘rapid progressors’ at 12 months had higher baseline sVCAM-1, haemoglobin A1c, cholesterol:high-density lipoprotein cholesterol ratio and LDL cholesterol.

Conclusions

IL-6 trans-signalling plays a pivotal role in vascular dysfunction in CIA. In early RA, sVCAM-1 was associated with progression of subclinical atherosclerosis. Inflammation from RA onset in CVD-susceptible individuals may accelerate atherosclerosis. IL-6 trans-signalling blockade may be beneficial to RA patients and perhaps for atherosclerosis in the general population.

Protective effects of phenethyl isothiocyanate on foam cell formation by combined treatment of oxidized low-density lipoprotein and lipopolysaccharide in THP-1 macrophage

Accumulation of cholesterol-laden macrophage foam cells characteristic of early stage atherosclerotic lesions. Phenethyl isothiocyanate (PEITC) is a naturally occurring isothiocyanate found in cruciferous vegetables that has reported a variety of activities including antioxidant and anti-inflammatory properties. However, the protective effect of PEITC on foam cell formation and its precise mechanism is not yet clear. Therefore, we investigated whether PEITC suppresses foam cell formation and regulates the expression of genes related to lipid accumulation, cholesterol efflux, and inflammation in THP-1 derived-macrophages. We exposed THP-1 derived-macrophages to oxidized low-density lipoprotein (ox-LDL) (20 μg/mL) and lipopolysaccharide (LPS) (500 ng/ml) to mimic foam cell formation. Here, PEITC downregulated the expression of lectin-like oxidized low-density lipoprotein receptor-1 (LOX-1), cluster of differentiation 36 (CD36), scavenger receptor A1 (SR-A1), and nuclear factor-κB (NF-κB), while upregulated ATP binding cassette subfamily A member 1 (ABCA1)/liver-X-receptor α (LXR-α)/peroxisome proliferator-activated receptor gamma (PPARγ) and sirtuin 1 (SIRT1) expression compared to co-treated with ox-LDL and LPS. Taken together, PEITC, at least in part, inhibits foam cell formation and reduces lipid accumulation in foam cells. Therefore, we suggest that PEITC may be a potential candidate for the treatment and prevention of vascular inflammation and atherosclerosis.

Integrating systematic biological and proteomics strategies to explore the pharmacological mechanism of danshen yin modified on atherosclerosis

This research utilized the systematic biological and proteomics strategies to explore the regulatory mechanism of Danshen Yin Modified (DSYM) on atherosclerosis (AS) biological network. The traditional Chinese medicine database and HPLC was used to find the active compounds of DSYM, Pharmmapper database was used to predict potential targets, and OMIM database and GeneCards database were used to collect AS targets. String database was utilized to obtain the other protein of proteomics proteins and the protein-protein interaction (PPI) data of DSYM targets, AS genes, proteomics proteins and other proteins. The Cytoscape 3.7.1 software was utilized to construct and analyse the network. The DAVID database is used to discover the biological processes and signalling pathways that these proteins aggregate. Finally, animal experiments and proteomics analysis were used to further verify the prediction results. The results showed that 140 active compounds, 405 DSYM targets and 590 AS genes were obtained, and 51 differentially expressed proteins were identified in the DSYM-treated ApoE-/- mouse AS model. A total of 4 major networks and a number of their derivative networks were constructed and analysed. The prediction results showed that DSYM can regulate AS-related biological processes and signalling pathways. Animal experiments have also shown that DSYM has a therapeutic effect on ApoE-/-mouse AS model (P < .05). Therefore, this study proposed a new method based on systems biology, proteomics, and experimental pharmacology, and analysed the pharmacological mechanism of DSYM. DSYM may achieve therapeutic effects by regulating AS-related signalling pathways and biological processes found in this research.

Raloxifene inhibits IL-6/STAT3 signaling pathway and protects against high-fat-induced atherosclerosis in ApoE-/- mice

AIMS

The signal transducer and activator of transcription 3 (STAT3) pathway plays an important role in inflammatory cascade process. Our previous studies found that Raloxifene targeted against IL-6/GP130 protein-protein interface and inhibited STAT3 phosphorylation induced by IL-6 in cancer cells. However, whether Raloxifene could suppress IL-6/STAT3 signaling pathway and attenuate atherosclerosis in high-fat diet (HFD)-induced mice remains unknown. The objective of this study was to explore the potential effect of Raloxifene on the prevention of atherosclerosis.

MAIN METHODS

HFD-induced atherosclerosis was established in apoliprotein E-deficient (ApoE ^-/-) mice. Mice by daily intragastric gavage with Raloxifene or vehicle as controls were provided. The human umbilical vein endothelial cells (HUVEC), Rat VSMC and RAW264.7 cell lines were used to evaluate the effect of Raloxifene in vitro.

KEY FINDINGS

We demonstrated that Raloxifene was effective in ameliorating HFD- induced atherosclerosis plaque burden and size. Histological analysis showed that the expression of IL-6, P-STAT3, ICAM-1, VCAM-1, CD68 and α-SMA were significantly decreased in the Raloxifene intervention group compared to HFD group. Moreover, we observed that IL-6 increased migration and cell viability of VSMCs and RAW264.7 cells, while Raloxifene treatment decreased migration and reduced cell viability of VSMCs and RAW264.7 cells stimulated by IL-6. Furthermore, this effect was related to blocking IL-6/STAT3 pathway.

SIGNIFICANCE

Raloxifene has effects on inhibiting atherosclerosis development, the underlying mechanisms might involve in inhibiting inflammation-related IL-6/STAT3 signaling pathway.

Curcumin inhibits the formation of atherosclerosis in ApoE-/- mice by suppressing cytomegalovirus activity in endothelial cells

BACKGROUND

Curcumin (Cur) is a hydrophobic polyphenol compound derived from the rhizome of the herb Curcuma longa. Cur has a wide spectrum of biological and pharmacological activities. It has been shown that human cytomegalovirus (HCMV) infection was an important risk factor for atherosclerosis (AS) and Cur exhibited an outstanding anti-HCMV effect. However, anti-AS effects of Cur remain unclear when HCMV infected endothelial cells.

AIMS

This study will investigate the anti-AS activities and mechanism of Cur,when HCMV infected in vivo and in vitro.

MATERIALS AND METHODS

Cur (0.5, 1, and 2 μM) was used to explore the anti-AS activities and mechanism after HCMV infected endothelial cells in vitro. ApoE^-/- mice were fed a high fat and cholesterol diet (HD) and given 4000,000 copies/mouse MCMV infection by intraperitoneal and treated with ganciclovir (5 mg/kg/d), Cur (25, 15 mg/kg/d) for 10 weeks in vivo.

KEY FINDINGS

As our results showed that Cur inhibited CMV replication and proliferation, reduced the intracellular ROS overproduction, decreased the release of inflammatory cytokines, down-regulated the level of HMGB1-TLRS-NF-κB signaling pathway-related proteins in vitro experiments. Cur reduced the serum levels of LDL-C, TC and TG, significantly decreased the formation of atherosclerotic plaque in the aorta, reduced the lipid deposition in liver and inflammatory damage in heart, lung and kidney in vivo experiments.

SIGNIFICANCE

This study showed that Cur prevent AS progression by inhibiting CMV activity and CMV-induced HMGB1-TLRS-NF-κB signaling pathway.

Long non-coding RNA CDKN2B-AS1 contributes to atherosclerotic plaque formation by forming RNA-DNA triplex in the CDKN2B promoter

BACKGROUND

Atherosclerosis involves a slow process of plaque formation on the walls of arteries, and comprises a leading cause of cardiovascular disease. Long non-coding RNAs (lncRNAs) have been implicated in the pathogenesis of atherosclerosis. In this study, we aim to explore the possible involvement of lncRNA 'cyclin-dependent kinase inhibitor 2B antisense noncoding RNA' (CDKN2B-AS1) and CDKN2B in the progression of atherosclerosis.

METHODS

Initially, we quantified the expression of CDKN2B-AS1 in atherosclerotic plaque tissues and, in THP-1 macrophage-derived, and human primary macrophage (HPM)-derived foam cells. Next, we established a mouse model of atherosclerosis using apolipoprotein E knockout (ApoE-/-) mice, where lipid uptake, lipid accumulation, and macrophage reverse cholesterol transport (mRCT) were assessed, in order to explore the contributory role of CDKN2B-AS1 to the progression of atherosclerosis. RIP and ChIP assays were used to identify interactions between CDKN2B-AS1, CCCTC-binding factor (CTCF), enhancer of zeste homologue 2 (EZH2), and CDKN2B. Triplex formation was determined by RNA-DNA pull-down and capture assay as well as EMSA experiment.

FINDINGS

CDKN2B-AS1 showed high expression levels in atherosclerosis, whereas CDKN2B showed low expression levels. CDKN2B-AS1 accelerated lipid uptake and intracellular lipid accumulation whilst attenuating mRCT in THP-1 macrophage-derived foam cells, HPM-derived foam cells, and in the mouse model. EZH2 and CTCF were found to bind to the CDKN2B promoter region. An RNA-DNA triplex formed by CDKN2B-AS1 and CDKN2B promoter was found to recruit EZH2 and CTCF in the CDKN2B promoter region and consequently inhibit CDKN2B transcription by accelerating histone methylation.

INTERPRETATION

The results demonstrated that CDKN2B-AS1 promotes atherosclerotic plaque formation and inhibits mRCT in atherosclerosis by regulating CDKN2B promoter, and thereby could be a potential therapeutic target for atherosclerosis.

Cytomegalovirus infection and atherosclerosis risk: A meta-analysis

Human cytomegalovirus (HCMV) infection is an important risk factor for atherosclerosis (AS). Numerous studies have been conducted to analyze the association between HCMV infection and risk of AS, but no clear consensus has been reached. So the objective of this paper was aimed to demonstrate the relationship between HCMV and AS by doing a meta-analysis. Relative literature was searched through the electronic databases PubMed, Embase, and CNKI. Data were accurately assessed and analyzed independently by two investigators. Ultimately, the 30 studies, involving 3328 cases and 2090 controls were included in our meta-analysis. The positive ratio of HCMV IgG, IgM, DNA and pp65 were, respectively, 63.26% (923/1459), 25.46% (69/271), 33.69% (381/1131), and 50.32% (158/314) in case patients. Meanwhile the positive ratio of HCMV IgG, IgM, DNA, and pp65 were, respectively, 52.12% (541/1038), 1.55% (3/194), 13.72% (79/576), and 12.26% (28/229) in control subjects. The positive ratio of HCMV infection was higher in atherosclerosis group than that in non-atherosclerosis group. Especially in Asian group, calculated odds ratios for the presence of HCMV infection in IgG-based HCMV tests, IgM-based tests, PCR-based tests, and pp65-based tests, expressed as OR (95% confidence intervals, 95%CI), were 3.07(95%CI 2.09-4.51), 8.92(95%CI 3.17-25.11), 6.75 (95%CI 3.50-13.02), and 5.72(95%CI 1.51-21.58), respectively. The meta-analysis results showed that HCMV infection is significant connected with an increased risk for AS.

Transgenic and gene knockout mice in gastric cancer research

Mouse models are useful tool for carcinogenic study. They will greatly enrich the understanding of pathogenesis and molecular mechanisms for gastric cancer. However, only few of mice could develop gastric cancer spontaneously. With the development and improvement of gene transfer technology, investigators created a variety of transgenic and knockout/knockin mouse models of gastric cancer, such as INS-GAS mice and gastrin knockout mice. Combined with helicobacter infection and carcinogens treatment, these transgenic/knockout/knockin mice developed precancerous or cancerous lesions, which are proper for gene function study or experimental therapy. Here we review the progression of genetically engineered mouse models on gastric cancer research, and emphasize the effects of chemical carcinogens or infectious factors on carcinogenesis of genetically modified mouse. We also emphasize the histological examination on mouse stomach. We expect to provide researchers with some inspirations on this field.

Adaptive immunity against gut microbiota enhances apoE-mediated immune regulation and reduces atherosclerosis and western-diet-related inflammation

Common features of immune-metabolic and inflammatory diseases such as metabolic syndrome, diabetes, obesity and cardiovascular diseases are an altered gut microbiota composition and a systemic pro-inflammatory state. We demonstrate that active immunization against the outer membrane protein of bacteria present in the gut enhances local and systemic immune control via apoE-mediated immune-modulation. Reduction of western-diet-associated inflammation was obtained for more than eighteen weeks after immunization. Immunized mice had reduced serum cytokine levels, reduced insulin and fasting glucose concentrations; and gene expression in both liver and visceral adipose tissue confirmed a reduced inflammatory steady-state after immunization. Moreover, both gut and atherosclerotic plaques of immunized mice showed reduced inflammatory cells and an increased M2 macrophage fraction. These results suggest that adaptive responses directed against microbes present in our microbiota have systemic beneficial consequences and demonstrate the key role of apoE in this mechanism that could be exploited to treat immune-metabolic diseases.

Immune-mediated mechanisms of atherosclerosis and implications for the clinic

INTRODUCTION

A large body of evidence supports the inflammatory hypothesis of atherosclerosis, and both innate and adaptive immune responses play important roles in all disease stages. Areas covered: Here, we review our understanding of the role of the immune response in atherosclerosis, focusing on the pathways currently amenable to therapeutic modulation. We also discuss the advantages or undesirable effects that may be foreseen from targeting the immune response in patients at high cardiovascular risk, suggesting new avenues for research. Expert commentary: There is an extraordinary opportunity to directly test the inflammatory hypothesis of atherosclerosis in the clinic using currently available therapeutics. However, a more balanced interpretation of the experimental and translational data is needed, which may help address and identify in more detail the appropriate settings where an immune pathway can be targeted with minimal risk.

Preclinical models of atherosclerosis. The future of Hybrid PET/MR technology for the early detection of vulnerable plaque

Cardiovascular diseases are the leading cause of death in developed countries. The aetiology is currently multifactorial, thus making them very difficult to prevent. Preclinical models of atherothrombotic diseases, including vulnerable plaque-associated complications, are now providing significant insights into pathologies like atherosclerosis, and in combination with the most recent advances in new non-invasive imaging technologies, they have become essential tools to evaluate new therapeutic strategies, with which can forecast and prevent plaque rupture. Positron emission tomography (PET)/computed tomography imaging is currently used for plaque visualisation in clinical and pre-clinical cardiovascular research, albeit with significant limitations. However, the combination of PET and magnetic resonance imaging (MRI) technologies is still the best option available today, as combined PET/MRI scans provide simultaneous data acquisition together with high quality anatomical information, sensitivity and lower radiation exposure for the patient. The coming years may represent a new era for the implementation of PET/MRI in clinical practice, but first, clinically efficient attenuation correction algorithms and research towards multimodal reagents and safety issues should be validated at the preclinical level.