Progression Of Atherosclerosis In ApoE Research Articles

PSRC1 overexpression attenuates atherosclerosis progression in apoE−/− mice by modulating cholesterol transportation and inflammation

AimsHuman genome-wide association studies (GWAS) have found that proline/serine-rich coiled-coil 1 (PSRC1) encodes a protein that is associated with serum lipid levels and coronary artery disease. In addition, our previous study showed that the cholesterol efflux capacity is decreased in macrophages following a treatment silencing Psrc1, indicating that PSRC1 has anti-atherosclerotic effects. However, the role of PSRC1 in the development of atherosclerosis is unknown. This study aims to explore the effect of PSRC1 on atherosclerosis and its underlying mechanisms. Method and resultsA recombinant adenovirus expressing Psrc1 (Ad-PSRC1) was constructed and transfected in RAW264.7 cells as well as injected intravenously into apoE−/− mice. The in vitro study showed that PSRC1 overexpression reduced the cellular cholesterol content, increased the cholesterol efflux capacity and inhibited foam cell formation by upregulating the expression of peroxisome proliferator-activated receptor γ (PPAR-γ) and liver X receptor α (LXR-α), which are key cholesterol transportation-related proteins. Infecting apoE−/− mice with Ad-PSRC1 inhibited the development of atherosclerotic lesions and enhanced atherosclerotic plaque stability. Consistent with these results, PSRC1 overexpression in apoE−/− mice decreased the plasma levels of TC, TG, LDL-C, TNF-α, IL-1β and IL-6, increased the plasma HDL-C levels and improved HDL function. Similarly, the PPAR-γ and LXR-α expression levels were upregulated in the liver and in peritoneal macrophages of PSRC1-overexpressing apoE−/− mice. Finally, the liver and peritoneal macrophages of apoE−/− mice displayed elevated expression of β-catenin, which is a direct downstream gene of PSRC1 and an upstream gene of PPAR-γ and LXR-α, but decreased activity of nuclear transcription factor (NF-κB), which acts as a key gene in the regulation of inflammation. ConclusionsPSRC1 protects against the development of atherosclerosis and enhances the stability of plaques by modulating cholesterol transportation and inflammation in macrophages and the liver of apoE−/− mice.

Quercetin protects against atherosclerosis by inhibiting dendritic cell activation.

Quercetin is a typical flavonol with atheroprotective effects, but the effect of quercetin on dendritic cell (DC) maturation in relation to atherosclerosis has not yet been clearly defined. Thus, we investigated whether quercetin can inhibit DC maturation and evaluated its potential value in atherosclerosis progression in ApoE-/- mice. Quercetin consumption inhibited DC activation, inflammatory response and suppressed the progression of atherosclerosis in ApoE-/- mice. Subsequently, quercetin treatment inhibited the phenotypic and functional maturation of DCs, as evidenced not only by downregulation of CD80, CD86, MHC-II, IL-6 and IL-12 but also by a reduction in the ability to stimulate T cell allogeneic proliferation. Finally, an in vitro study demonstrated that quercetin inhibited DC maturation via upregulation of Dabs, which then downregulated the Src/PI3K/Akt-NF-κB-inflammatory pathways. Our data indicate that quercetin attenuates atherosclerosis progression by regulating DC activation via Dab2 protein expression.

Sinigrin attenuates the progression of atherosclerosis in ApoE−/− mice fed a high-cholesterol diet potentially by inhibiting VCAM-1 expression

Atherosclerosis is a complex inflammatory disease associated with elevated levels of atherogenic molecules for leukocyte recruitment. Sinigrin (2-propenylglucosinolate) is found mainly in broccoli, brussels sprouts, and black mustard seeds. Recently, sinigrin has received attention for its role in disease prevention and health promotion. In this study, we examined the effect of sinigrin on development of atherosclerosis in ApoE−/− mice and the expression of adhesion molecules in vascular smooth muscle cells (VSMCs). The serum concentrations of lactate dehydrogenase (LDH), triglyceride (TG), total cholesterol (TC), low density lipoprotein (LDL), calcium (Ca2+), and pro-inflammatory cytokines were reduced by sinigrin treatment in ApoE−/− mice. In addition, oral administration of sinigrin attenuated the mRNA expression of vascular cell adhesion molecule-1 (VCAM-1), intercellular adhesion molecule-1 (ICAM-1), C-C motif chemokine ligand 2 (CCL2), and CCL5 on aorta tissues and 3-hydroxy-3-methylglutaryl-coenzyme A reductase (HMGR), liver X receptor (LXR), sterol regulatory element-binding protein-2 (SREBP-2), and low density lipoprotein receptor (LDLR) on liver tissues in ApoE−/− mice. To provide a potential mechanism underlying the action of sinigrin, we evaluated the in vitro effect of sinigrin on the expression of the VCAM-1 in TNF-α-induced VSMCs. The increased expression of VCAM-1 by TNF-α stimulation was significantly suppressed by the treatment of sinigrin (1–100 μg/ml) and sinigrin inhibited the nuclear translocation of NF-κB and the phosphorylation of p38 MAPK and JNK pathways, suggesting that sinigrin decreases the TNF-α-stimulated VCAM-1 expression through the suppression of NF-κB and MAP kinases signaling pathways. Overall, sinigrin has the potential to be used in reducing the risks of atherosclerosis.

Tetramethylpyrazine suppresses lipid accumulation in macrophages via upregulation of the ATP-binding cassette transporters and downregulation of scavenger receptors.

Tetramethylpyrazine (TMP), a biologically active ingredient first extracted from the Chinese medicinal plant Ligusticum wallichii Franchat., has athero-protective activity, yet the particular mechanisms have not been completely explored. The present study was designed to investigate the effect of TMP and its possible mechanisms in RAW264.7 macrophages and apolipoprotein E-deficient (ApoE-/-) mice. TMP treatment markedly increased the cholesterol efflux and inhibited oxidized low-density lipoprotein (ox-LDL) uptake, thus, ameliorating lipid accumulation in macrophages. In addition, TMP significantly increased the protein and mRNA expression of ATP-binding cassette transportersA1 (ABCA1) andG1 (ABCG1), while suppressing the protein and mRNA expression of classA scavenger receptor (SR-A) and the cluster of differentiation36 (CD36). Moreover, the effects of TMP on the upregulation of the expression of ABCA1 and ABCG1, the downregulation of the expression of CD36 and SR-A, the increase of cholesterol efflux and the decrease of lipid accumulation as well as the uptake of ox-LDL were mediated by the inactivation of PI3K/Akt and p38 MAPK. Furthermore, TMP upregulated the protein stability of ABCA1 without affecting ABCG1. Accordingly, TMP regulated the expression of SR-A, CD36, ABCA1 and ABCG1 in aortas of ApoE-/- mice, which resembled the findings observed in macrophages. TMP was also capable of delaying the progression of atherosclerosis in ApoE-/- mice. These findings revealed that TMP downregulates scavenger receptors and upregulates ATP-binding cassette transporters via PI3K/Akt and p38 MAPK signaling, thus suppressing lipid accumulation in macrophages.

Inflammation and Vascular Effects after Repeated Intratracheal Instillations of Carbon Black and Lipopolysaccharide.

Inflammation and oxidative stress are considered the main drivers of vasomotor dysfunction and progression of atherosclerosis after inhalation of particulate matter. In addition, new studies have shown that particle exposure can induce the level of bioactive mediators in serum, driving vascular- and systemic toxicity. We aimed to investigate if pulmonary inflammation would accelerate nanoparticle-induced atherosclerotic plaque progression in Apolipoprotein E knockout (ApoE-/-) mice. ApoE -/- mice were exposed to vehicle, 8.53 or 25.6 μg nanosized carbon black (CB) alone or spiked with LPS (0.2 μg/mouse/exposure; once a week for 10 weeks). Inflammation was determined by counting cells in bronchoalveolar lavage fluid. Serum Amyloid A3 (Saa3) expression and glutathione status were determined in lung tissue. Plaque progression was assessed in the aorta and the brachiocephalic artery. The effect of vasoactive mediators in plasma of exposed ApoE-/- mice was assessed in aorta rings isolated from naïve C57BL/6 mice. Pulmonary exposure to CB and/or LPS resulted in pulmonary inflammation with a robust influx of neutrophils. The CB exposure did not promote plaque progression in aorta or BCA. Incubation with 0.5% plasma extracted from CB-exposed ApoE-/- mice caused vasoconstriction in aorta rings isolated from naïve mice; this effect was abolished by the treatment with the serotonin receptor antagonist Ketanserin. In conclusion, repeated pulmonary exposure to nanosized CB and LPS caused lung inflammation without progression of atherosclerosis in ApoE-/- mice. Nevertheless, plasma extracted from mice exposed to nanosized CB induced vasoconstriction in aortas of naïve wild-type mice, an effect possibly related to increased plasma serotonin.

VNN1 promotes atherosclerosis progression in apoE−/− mice fed a high-fat/high-cholesterol diet

Accumulated evidence shows that vanin-1 (VNN1) plays a key part in glucose metabolism. We explored the effect of VNN1 on cholesterol metabolism, inflammation, apoptosis in vitro, and progression of atherosclerotic plaques in apoE−/− mice. Oxidized LDL (Ox-LDL) significantly induced VNN1 expression through an ERK1/2/cyclooxygenase-2/PPARα signaling pathway. VNN1 significantly increased cellular cholesterol content and decreased apoAI and HDL-cholesterol (HDL-C)-mediated efflux by 25.16% and 23.13%, respectively, in THP-1 macrophage-derived foam cells (P < 0.05). In addition, VNN1 attenuated Ox-LDL-induced apoptosis through upregulation of expression of p53 by 59.15% and downregulation of expression of B-cell lymphoma-2 127.13% in THP-1 macrophage (P < 0.05). In vivo, apoE−/− mice were divided randomly into two groups and transduced with lentivirus (LV)-Mock or LV-VNN1 for 12 weeks. VNN1-treated mice showed increased liver lipid content and plasma levels of TG (124.48%), LDL-cholesterol (119.64%), TNF-α (148.74%), interleukin (IL)-1β (131.81%), and IL-6 (156.51%), whereas plasma levels of HDL-C (25.75%) were decreased significantly (P < 0.05). Consistent with these data, development of atherosclerotic lesions was increased significantly upon infection of apoE−/− mice with LV-VNN1. These observations suggest that VNN1 may be a promising therapeutic candidate against atherosclerosis.

Abstract 654: Loss of SPRR3 In ApoE -/- Mice Leads to Increased Atheroma Vulnerability and Evidence of Plaque Rupture and Cardiac Infarcts

Atheroma rupture is the leading cause of myocardial infarction. While studies have examined inflammatory cell-mediated effects on plaque vulnerability, less is known about the role of vascular smooth muscle cells (VSMCs) or specific molecular players in the maintenance of atheroma stability. We reported that loss of small proline-rich repeat protein 3 (SPRR3), enriched in atheroma VSMCs, leads to increased VSMC death and significantly accelerates atherosclerosis progression in ApoE -/- mice. Here, we show that loss of SPRR3 promotes features in plaques of brachiocephalic arteries common to unstable lesions, such as increased necrotic core size, reduced cap collagen content, and reduced VSMC content. Moreover, ApoE -/- mice lacking SPRR3 develop coronary artery lesions with advanced features, including intraplaque hemorrhage. In addition, Sprr3 -/- ApoE -/- mice fed a high-fat diet for 6 months develop spontaneous myocardial infarction. In vitro , SPRR3 deficient VSMCs show reduced expression of procollagen type I, an event associated with Akt activation. SPRR3-deficient VSMCs also show increased expression of MMP2 transcripts, and aortic root lesions of Sprr3 -/- ApoE -/- mice have increased gelatinase activity consistent with MMP2 activation. Our data demonstrate that SPRR3 loss in ApoE -/- mice decreases VSMC survival and collagen I synthesis while increasing MMP2 synthesis and activity, resulting in atheroma instability with evidence of downstream myocardial infarction. Taken together the results present the Sprr3 -/- ApoE -/- mouse as an experimental model of plaque rupture. This model will be used for additional experimental studies including in vivo genetic modulation of the Akt pathway as well as in vitro studies to determine phenotypic outcome, i.e. coronary arterial lesions, myocardial infarction, VSMC survival and collagen synthesis. We hope to establish a mechanistic link between altered Akt signaling and matrix integrity in the context of atheroma rupture, as well as potentially use SPRR3 as a molecular marker which could lead to detection of plaque instability as well as therapeutic intervention methodologies.

ATRQβ-001 vaccine prevents atherosclerosis in apolipoprotein E-null mice.

Angiotensin II (AngII) type 1 receptor (AT1R) blockers have been proved to reduce atherosclerosis. Previously, we have invented ATRQβ-001 vaccine which showed a desirable blocking effect for AT1R. The purpose of this study was to investigate whether ATRQβ-001 vaccine would prevent atherosclerosis in apolipoprotein E-null (ApoE-/-) mice. Male ApoE-/- mice were administered with ATRQβ-001 vaccine, Qβ virus-like particles, valsartan or vehicle over a period of 24 weeks. In vitro, human coronary artery endothelial cells preincubated with the anti-ATR-001 antibody, the neutralization antibody or valsartan for 2 h, were treated with AngII for 24 h. Histological stain and molecule biology methods were used to assess the atheroprotective effect of the vaccine. ATRQβ-001 vaccine significantly reduced the lesion area and promoted the stability of atherosclerotic plaque. Meanwhile, macrophage infiltration as well as the expressions of adhesion molecules and monocyte chemoattractant protein-1 was obviously decreased in the ATRQβ-001 vaccine group. Additionally, the vaccine markedly reduced the apoptosis in the lesions of the ApoE-/- mice. In vitro, the anti-ATR-001 antibody inhibited endothelial apoptosis induced by AngII. Furthermore, ATRQβ-001 vaccine exhibited a dramatical attenuation in the expressions of lectin-like oxidized low-density lipoprotein receptor-1 and AT1R in the aortic. More importantly, compared with the valsartan group, no obvious feedback of the plasma renin-angiotensin system was elicited in the vaccine group. The results demonstrated that ATRQβ-001 vaccine reduced the progression of atherosclerosis in ApoE-/- mice without obvious feedback of renin-angiotensin system.

Transient Receptor Potential Ankyrin 1 Channel Involved in Atherosclerosis and Macrophage-Foam Cell Formation.

Transient receptor potential ankyrin 1 channel (TRPA1) plays an important role in the pathogenesis of inflammatory diseases, yet its role and the underlying mechanism in atherosclerosis remain unclear. We aimed to investigate the role of TRPA1 in atherosclerosis and foam-cell formation in vivo in mice and in vitro in mouse macrophages. Histopathology was examined by hematoxylin and eosin staining, levels of cytokines and lipid profile were evaluated by assay kits, and protein expression was determined by western blot analysis. TRPA1 expression was increased in macrophage foam cells in atherosclerotic aortas of apolipoprotein E-deficient (apoE-/-) mice. Atherosclerotic lesions, hyperlipidemia and systemic inflammation were worsened with chronic administration of the TRPA1 channel antagonist HC030031 or genetic ablation of TRPA1 (TRPA1-/-) in apoE-/- mice. Treatment with allyl isothiocyanate (AITC, a TRPA1 agonist) retarded the progression of atherosclerosis in apoE-/- mice but not apoE-/-TRPA1-/- mice. Mouse macrophages showed oxidized low-density lipoprotein (oxLDL) activated TRPA1 channels. OxLDL-induced lipid accumulation of macrophages was exacerbated by HC030031 or loss of function of TRPA1. Inhibition of TRPA1 activity did not alter oxLDL internalization but impaired cholesterol efflux by downregulating the ATP-binding cassette transporters. Furthermore, tumor necrosis factor-α-induced inflammatory response was attenuated in AITC-activated macrophages. TRPA1 may be a pivotal regulator in the pathogenesis of atherosclerosis and cholesterol metabolism of macrophage foam cells.

Distinct gene signatures in aortic tissue from ApoE-/- mice exposed to pathogens or Western diet.

BackgroundAtherosclerosis is a progressive disease characterized by inflammation and accumulation of lipids in vascular tissue. Porphyromonas gingivalis (Pg) and Chlamydia pneumoniae (Cp) are associated with inflammatory atherosclerosis in humans. Similar to endogenous mediators arising from excessive dietary lipids, these Gram-negative pathogens are pro-atherogenic in animal models, although the specific inflammatory/atherogenic pathways induced by these stimuli are not well defined. In this study, we identified gene expression profiles that characterize P. gingivalis, C. pneumoniae, and Western diet (WD) at acute and chronic time points in aortas of Apolipoprotein E (ApoE-/-) mice.ResultsAt the chronic time point, we observed that P. gingivalis was associated with a high number of unique differentially expressed genes compared to C. pneumoniae or WD. For the top 500 differentially expressed genes unique to each group, we observed a high percentage (76%) that exhibited decreased expression in P. gingivalis-treated mice in contrast to a high percentage (96%) that exhibited increased expression in WD mice. C. pneumoniae treatment resulted in approximately equal numbers of genes that exhibited increased and decreased expression. Gene Set Enrichment Analysis (GSEA) revealed distinct stimuli-associated phenotypes, including decreased expression of mitochondrion, glucose metabolism, and PPAR pathways in response to P. gingivalis but increased expression of mitochondrion, lipid metabolism, carbohydrate and amino acid metabolism, and PPAR pathways in response to C. pneumoniae; WD was associated with increased expression of immune and inflammatory pathways. DAVID analysis of gene clusters identified by two-way ANOVA at acute and chronic time points revealed a set of core genes that exhibited altered expression during the natural progression of atherosclerosis in ApoE-/- mice; these changes were enhanced in P. gingivalis-treated mice but attenuated in C. pneumoniae-treated mice. Notable differences in the expression of genes associated with unstable plaques were also observed among the three pro-atherogenic stimuli.ConclusionsDespite the common outcome of P. gingivalis, C. pneumoniae, and WD on the induction of vascular inflammation and atherosclerosis, distinct gene signatures and pathways unique to each pro-atherogenic stimulus were identified. Our results suggest that pathogen exposure results in dysregulated cellular responses that may impact plaque progression and regression pathways.Electronic supplementary materialThe online version of this article (doi:10.1186/1471-2164-15-1176) contains supplementary material, which is available to authorized users.

Docosahexaenoic acid supplementation modifies fatty acid incorporation in tissues and prevents hypoxia induced-atherosclerosis progression in apolipoprotein-E deficient mice

The n-3 polyunsaturated fatty acid, docosahexaenoic acid (DHA), displays anti-inflammatory properties that may prevent atherosclerosis progression. Exposure of apolipoprotein-E deficient (ApoE−/−) mice to chronic intermittent hypoxia (CIH) accelerates atherosclerosis progression. Our aim was to assess DHA-supplementation influence on fatty acid incorporation in different tissues/organs and on atherosclerosis progression in ApoE−/− mice exposed to CIH.ApoE−/− mice were exposed to CIH or normoxia (N) and randomized to four groups (N control, CIH control, N+DHA, and CIH+DHA). DHA-supplementation enhanced DHA and reduced arachidonic acid (AA) contents in tissues/organs. CIH control mice exhibited increased atherosclerosis lesion sizes compared to N control mice. DHA prevented CIH induced atherosclerosis but did not improve atherosclerosis burden in N mice. Aortic matrix metalloproteinase-2 (MMP-2) expression was decreased in CIH+DHA mice (p=0.007).DHA-supplementation prevented CIH-induced atherosclerosis acceleration. This was associated with a decrease of AA incorporation and of aortic MMP-2 gene expression.

Serum metabonomic analysis of apoE(-/-) mice reveals progression axes for atherosclerosis based on NMR spectroscopy.

Atherosclerosis is a multifactorial and progressive disease commonly correlated with a high fat diet. The aim of this study was to identify potential biomarkers for the early diagnosis and monitoring of the progression of atherogenesis in apoE(-/-) mice using (1)H NMR-based metabonomics. The apoE(-/-) mice were split into four groups according to the duration of high fat feeding (0 w, 2 w, 4 w and 8 w), and each group possessed different pathological characteristics. Serum (1)H NMR-based metabonomics selectively captured the metabotypes that correlated with the degree of atherosclerosis, showing a time-dependent progression from the physiological to pathophysiological status. It was noted that changes in HDL, choline, taurine, glycine and glucose may be regarded as specific biomarkers of the early stage of atherosclerosis. With the progression of atherosclerosis, disorders in the metabolism of amino acids such as valine, alanine and methionine appeared when large atherosclerotic plaques existed. Multiple biochemical disorders involving lipid metabolism, energy and fatty acid metabolism were observed in the progression of atherosclerosis in apoE(-/-) mice. This study demonstrated that (1)H NMR-based metabonomics can provide biochemical information about the progression of atherogenesis and offer a non-invasive means to discover potential biomarkers for the onset and development of atherosclerosis.

An agomir of miR-144-3p accelerates plaque formation through impairing reverse cholesterol transport and promoting pro-inflammatory cytokine production.

AimsATP-binding cassette transporter A1 (ABCA1) mediates the efflux of cholesterol and phospholipids to lipid-poor apolipoproteins, which then form nascent HDL, a key step in the mechanism of reverse cholesterol transport (RCT). While a series of microRNAs (miRNAs) have been identified as potent post-transcriptional regulators of lipid metabolism, their effects on ABCA1 function and associated mechanisms remain unclear.Methods and ResultsABCA1 was identified as a potential target of miR-144-3p, based on the results of bioinformatic analysis and the luciferase reporter assay, and downregulated after transfection of cells with miR-144-3p mimics, as observed with real-time PCR and western blot. Moreover, miR-144-3p mimics (agomir) enhanced the expression of inflammatory factors, including IL-1β, IL-6 and TNF-α, in vivo and in vitro, inhibited cholesterol efflux in THP-1 macrophage-derived foam cells, decreased HDL-C circulation and impaired RCT in vivo, resulting in accelerated pathological progression of atherosclerosis in apoE−/− mice. Clinical studies additionally revealed a positive correlation of circulating miR-144-3p with serum CK, CK-MB, LDH and AST in subjects with AMI.ConclusionsOur findings clearly indicate that miR-144-3p is essential for the regulation of cholesterol homeostasis and inflammatory reactions, supporting its utility as a potential therapeutic target of atherosclerosis and a promising diagnostic biomarker of AMI.

Rate of Atherosclerosis Progression in ApoE−/− Mice Long After Discontinuation of Cola Beverage Drinking

This study was conducted in order to evaluate the effect of cola beverages drinking on atherosclerosisand test the hypothesis whether cola beverages consumption at early life stages might affect the development and progression of atherosclerosis later in life.ApoE−/− C57BL/6J mice (8 week-old) were randomized in 3 groups (n = 20 each) according to free accessto water (W), sucrose sweetened carbonated cola drink(C) or aspartame-acesulfame K sweetened carbonated ‘light’ cola drink (L)for the next 8 weeks. Drinking treatment was ended by switching C and L groups to drinking water. Four mice per group and time were sequentially euthanized: before treatment (8weeks-old), at the end of treatment (16 weeks-old) and after treatment discontinuation (20 weeks-old, 24 weeks-old, 30 week-old mice). Aortic roots and livers were harvested, processed for histology and serial cross-sections were stained. Aortic plaque area was analyzed and plaque/media-ratio was calculated.Early consumption of cola drinks accelerated atherosclerotic plaque progression favoring the interaction between macrophages and myofibroblasts, without the participation of either T lymphocytes or proliferative activity. Plaque/media-ratio varied according to drink treatment (F2,54 = 3.433, p<0.04) and mice age (F4,54 = 5.009, p<0.03) and was higher in C and L groups compared with age-matched W group (p<0.05 at 16 weeks and 20 weeks, p<0.01 at 24 weeks and 30 weeks). Natural evolution of atherosclerosis in ApoE−/− mice (W group) evidenced atherosclerosis acceleration in parallel with a rapid increase in liver inflammation around the 20 weeks of age.Cola drinking within the 8–16 weeks of age accelerated atherosclerosis progression in ApoE−/− mice favoring aortic plaque enlargement (inward remodeling) over media thinning all over the study time. Data suggest that cola drinking at early life stages may predispose to atherosclerosis progression later in life in ApoE−/− mice.

Tannerella forsythia BspA increases the risk factors for atherosclerosis in ApoE−/− mice

The aim of this study was to evaluate the effects of Tannerella forsythia and its major surface virulence factor, BspA, on the progression of atherosclerosis in ApoE(-/-) mice and the expression of lipid metabolism-related genes. PMA-differentiated THP-1 cells were treated with BspA to detect foam cell formation. The proximal aortas of ApoE(-/-) mice injected with T.forsythia or BspA were stained with oil red O to examine lipid deposition. The serum levels of CRP, HDL, and LDL were detected by ELISA. The liver tissue of T.forsythia- or BspA-injected ApoE(-/-) mice was examined for mRNA expression of lipid metabolism-related genes, such as liver X receptors (LXRα and LXRβ) and ATP-binding cassette transporter A1 (ABCA1). Tannerella forsythia and BspA induced foam cell formation in THP-1 cells and accelerated the progression of atherosclerotic lesions in ApoE(-/-) mice. Mouse serum levels of CRP and LDL were increased, and HDL was decreased by T.forsythia and BspA. The expression levels of LXRα and LXRβ, and ABCA1 in liver tissue were decreased by T.forsythia and BspA. Tannerella forsythia and BspA augmented atherosclerotic lesion progression in ApoE(-/-) mice. This process may be associated with downregulation of lipid metabolism-related gene expression.

Testing the Iron Hypothesis in a Mouse Model of Atherosclerosis

Hepcidin, the iron-regulatory hormone and acute phase reactant, is proposed to contribute to the pathogenesis of atherosclerosis by promoting iron accumulation in plaque macrophages, leading to increased oxidative stress and inflammation in the plaque (the "iron hypothesis"). Hepcidin and iron may thus represent modifiable risk factors in atherosclerosis. We measured hepcidin expression in Apoe(-/-) mice with varying diets and ages. To assess the role of macrophage iron in atherosclerosis, we generated Apoe(-/-) mice with macrophage-specific iron accumulation by introducing the ferroportin ffe mutation. Macrophage iron loading was also enhanced by intravenous iron injection. Contrary to the iron hypothesis, we found that hepatic hepcidin expression was not increased at any stage of the atherosclerosis progression in Apoe(-/-) or Apoe/ffe mice and that the atherosclerotic plaque size was not increased in mice with elevated macrophage iron. Our results strongly argue against any significant role of macrophage iron in atherosclerosis progression in mice.

β3-Adrenoceptor activation attenuates atherosclerotic plaque formation in ApoE−/− mice through lowering blood lipids and glucose

To examine the effects of β3-adrenoceptor (β3-AR) activation on atherosclerotic plaque development in ApoE(-/-) mice. Thirty six week-old male ApoE(-/-) mice on a high-fat diet were treated with atorvastatin (10 mg·kg(-1)·d(-1), po), BRL37344 (β3-AR agonist, 1.65 or 3.30 μg/kg, ip, twice a week) or SR52390A (β3-AR antagonist, 50 μg/kg, ip, twice a week) for 12 weeks. Wild-type C57BL/6J mice receiving a normal diet were taken as healthy controls. At the end of the treatments, serum levels of triglycerides (TG), total cholesterol (TC), high-density lipoprotein cholesterol (HDL-C), non-high density lipoprotein cholesterol (nHDL-C), glucose and insulin were measured. The thoracic aortas were dissected out, the area of atherosclerotic plaques and extent of fibrosis in the plaques were examined using HE and Masson's trichome staining, respectively. Compared to wild-type mice, ApoE(-/-) mice fed on a high-fat diet exhibited prominent hyperlipidemia and insulin resistance, associated with large area of atherosclerotic plaques and great extent of fibrosis in aortas. Atorvastatin significantly decreased the serum levels of TC and nHDL-C, and reduced the plaque area and collagen content in aortas. BRL37344 significantly decreased the serum levels of TG, TC, nHDL-C, glucose and insulin, and increased HDL-C and the insulin sensitivity, and dose-dependently reduced the plaque area and collagen content in aortas. SR52390A treatment did not affect any parameters studied. The β3-AR agonist impedes the progression of atherosclerosis in ApoE(-/-) mice, through improvement of the lipid and glucose profiles.

ASSA13-03-17 b3-Adrenoceptor Activation Improves the Formation of Atherosclerosis Plaque in Aged ApoE-Deficient Mice

Objective To study the effects of β 3 -adrenoceptor (β 3 -AR) activation on atherosclerotic plaque development in aged apolipoprotein E-deficient (ApoE -/- ) mice. Methods Male ApoE -/- mice were fed with a high-fat diet, starting on 10 weeks of age. Starting from 36 weeks of age, mice were randomly treated with atorvastatin (10 mg · kg -1 ·d -1 , by gavage), the β 3 -AR agonist BRL37344 (1.65 or 3.30 μg·kg -1 , twice a week, by intraperitoneal injection), the β3-AR antagonist SR52390A (50 μg·kg -1 , twice a week, by intraperitoneal injection), or saline vehicle (twice a week, by intraperitoneal injection) for 12 weeks (n = 10 per group). A group of wild-type C57BL/6J mice receiving normal diet was included as a healthy control. At the end of the 12-week treatment period, serum concentration of lipids were measured. Atherosclerotic plaque in the thoracic aorta was examined using Hematoxy-eosin staining. The extent of fibrosis in the plaque was examined using Masson staining. Western blot was uesed to determine the ApoA-I and SR-BI protein expression. Real-time quantitative PCR was used to determine β 3 -AR mRNA in the white adipose tissue and the ApoA-I, ApoA-II and SR-BI mRNA expression in liver tissue. Results High-fat diet in ApoE -/- mice led to hyperlipidemia and the area of and the extent of fibrosis in atherosclerotic plaque (P 3 -AR mRNA and SR-BI mRNA were lower, ApoA-I and ApoA-II mRNA were higher in ApoE -/- mice (P -/- mice receiving vehicle). Treatment with the β 3 -AR agonist BRL37344 decreased serum concentration of triglyceride, total cholesterol and non-high density lipoprotein cholesterol. The treatment increased high density lipoprotein cholesterol, downregulated of ApoA-I, ApoA-II and SR-BI expression and upregulated the β 3 -AR mRNA expression (P -/- mice receiving vehicle). Similar to atorvastatin, BRL37344 treatment dose-dependently reduced the plaque area and collagen content (P -/- mice receiving vehicle at a dose of 3.30 but not 1.65 μg·kg -1 ). Treatment with the β 3 -AR antagonist SR52390A did not affect any parameters (P > 0.05 for all measures vs. ApoE -/- mice receiving vehicle). Conclusions β 3 -AR agonist impeded the progression of atherosclerosis in ApoE -/- mice, possibly through improvement of lipid profile, ApoA-I, ApoA-II and SR-BI mRNA.

Contrast ultrasound imaging of the aorta does not affect progression of atherosclerosis in ApoE−/− mice

Ultrasound Contrast Agents (UCAs) are used clinically to enhance ultrasound imaging of the cardiovascular system. Adverse biological effects have been noted after administration of UCAs, and more research is needed for an understanding of the biological effects of UCAs. Male ApoE−/− mice (8 weeks old, n=38) were intravenously infused with the Definity® UCA (2×1010 UCA/hr) and either exposed to 2.8‐MHz 10‐Hz PRF 1.4‐μs PD 2‐min ED 1.4‐MPa PRPA ultrasound or sham exposed, and then consumed either a chow or Western diet for either 4 or 8 weeks after ultrasound exposure (n=4–5 per group). Plasma total cholesterol was greater in the Western diet group than the chow group for all timepoints after baseline (p&lt;0.0001). Plasma von Willebrand Factor (vWF), a biomarker of endothelial function, was elevated in Western diet animals compared to chow animals (p&lt;0.05). Atheroma thickness was greater in animals consuming the Western diet than in chow‐fed animals (p&lt;0.001), and in animals euthanized after 8 weeks than after 4 weeks (p&lt;0.005). Ultrasound did not affect plasma total cholesterol levels, plasma vWF or atheroma thickness. [Supported by NIH R37EB002641]

18F-FDG PET Imaging of Murine Atherosclerosis: Association with Gene Expression of Key Molecular Markers

AimTo study whether 18F-FDG can be used for in vivo imaging of atherogenesis by examining the correlation between 18F-FDG uptake and gene expression of key molecular markers of atherosclerosis in apoE−/− mice.MethodsNine groups of apoE−/− mice were given normal chow or high-fat diet. At different time-points, 18F-FDG PET/contrast-enhanced CT scans were performed on dedicated animal scanners. After scans, animals were euthanized, aortas removed, gamma counted, RNA extracted from the tissue, and gene expression of chemo (C-X-C motif) ligand 1 (CXCL-1), monocyte chemoattractant protein (MCP)-1, vascular cell adhesion molecule (VCAM)-1, cluster of differentiation molecule (CD)-68, osteopontin (OPN), lectin-like oxidized LDL-receptor (LOX)-1, hypoxia-inducible factor (HIF)-1α, HIF-2α, vascular endothelial growth factor A (VEGF), and tissue factor (TF) was measured by means of qPCR.ResultsThe uptake of 18F-FDG increased over time in the groups of mice receiving high-fat diet measured by PET and ex vivo gamma counting. The gene expression of all examined markers of atherosclerosis correlated significantly with 18F-FDG uptake. The strongest correlation was seen with TF and CD68 (p<0.001). A multivariate analysis showed CD68, OPN, TF, and VCAM-1 to be the most important contributors to the uptake of 18F-FDG. Together they could explain 60% of the 18F-FDG uptake.ConclusionWe have demonstrated that 18F-FDG can be used to follow the progression of atherosclerosis in apoE−/− mice. The gene expression of ten molecular markers representing different molecular processes important for atherosclerosis was shown to correlate with the uptake of 18F-FDG. Especially, the gene expressions of CD68, OPN, TF, and VCAM-1 were strong predictors for the uptake.