Abstract 273: Shear Stress--Induced Atherosclerotic Plaque Regression Explained by Increased Macrophage Efferocytosis and Migration

2014 ◽  
Vol 34 (suppl_1) ◽  
Author(s):  
Stefania Simeone ◽  
Talin Ebrahimian ◽  
Veronique Michaud ◽  
Stephanie Lehoux
Keyword(s):  
Shear Stress ◽  
High Fat Diet ◽  
Cell Movement ◽  
Atherosclerotic Plaques ◽  
High Shear ◽  
High Fat ◽  
Mmp Inhibitor ◽  
Plaque Regression ◽  
Static Conditions

Atherosclerotic plaques form in regions of low blood flow, whereas vessels exposed to high shear stress remain lesion-free. Using a model of arteriovenous fistula (AVF) in mice, we have previously shown that exposing established atherosclerotic plaques to elevated shear stress leads to lesion regression and increased matrix metalloproteinase (MMP) activity. MMP inhibition abolished shear stress-induced plaque regression and macrophage migration, suggesting that facilitating inflammatory cell movement within the plaque contributes to regression. We hypothesized that increased shear stress also leads to more efficient efferocytosis, another important hallmark of regression. LDLR-/- mice were placed on a high-fat diet. Sham and AVF surgery was performed at week 12 and mice were kept on a high-fat diet for a further 4 weeks (wk16). Control mice were sacrificed at wk12. The AVF procedure increases the shear stress in the brachiocephalic artery (BCA) but does not alter serum lipid levels. Using 3D echocardiography between wk12 and wk16, we observed that plaques progressed in the BCA of sham mice, whereas the AVF plaques regressed. Furthermore, the size of the necrotic core was significantly smaller in the AVF plaques than sham and control (P<0.05). This could be due to increased efferocytosis in the AVF, as verified using an in vitro model of the plaque environment. Endothelial cells (EC) were co-cultured with macrophages in a system wherein ECs are exposed to high or no shear stress and macrophages are exposed to the EC effluent. Uptake of apoptotic cells by macrophages was 50% higher in the high shear vs. static conditions (P<0.01). The MMP inhibitor, GM6001, had no effect on efferocytosis. However, a cytokine array on the co-culture effluent revealed interesting candidates. CCL3 and GMCSF, both of which have been associated with enhanced efferocytosis, were more highly expressed in high shear conditions vs. static. Our findings suggest that shear stress increases efferocytosis, leading to smaller necrotic cores through a mechanism that probably involves altered cytokine production. The combination of more efficient cell migration and efferocytosis in the presence of increased shear stress likely leads to plaque regression.

Abstract 476: Shear Stress-induced Atherosclerotic Plaque Regression is Reversed by Regulation of Macrophage Mobility via Matrix Metalloproteinase Inhibition

2013 ◽  
Vol 33 (suppl_1) ◽  
Author(s):  
Stefania Simeone ◽  
Talin Ebrahimian ◽  
Veronique Michaud ◽  
Stephanie Lehoux
Keyword(s):  
Shear Stress ◽  
High Fat Diet ◽  
Fold Increase ◽  
Atherosclerotic Plaques ◽  
High Shear ◽  
High Fat ◽  
Gelatinase Activity ◽  
Mmp Inhibitor ◽  
Post Surgery ◽  
Plaque Regression

Atherosclerotic plaques form in regions of low blood flow, whereas vessels exposed to high shear stress remain lesion-free. We hypothesized that exposing established atherosclerotic plaques to elevated shear stress leads to lesion regression by facilitating inflammatory cell movement within the plaque. We developed a model of arteriovenous fistula (AVF) in mice, where the right carotid artery is anastomosed into the jugular vein. LDLR-/- mice were placed on a high-fat diet. Control mice were sacrificed at week 12, which coincided with sham and AVF surgery. Sham and AVF mice were kept on a high-fat diet for a further 4 weeks. This procedure increases the shear stress in the brachiocephalic artery (BCA) and leads to a 51% plaque regression in AVF. All groups had comparable lipid levels. However, BCA plaque macrophage, smooth muscle cell and collagen content was halved in AVF. We observed greater gelatinase activity in plaques of AVF mice, suggesting a role for matrix metalloproteinases (MMPs) in plaque regression. MMP-9 and MMP-3 expression was increased in AVF plaques whereas MMP-2 and MMP-14 expression was decreased (p<0.05). A separate group of mice was therefore treated post-surgery with an MMP inhibitor, doxycycline, or with a TIMP-1 over-expressing plasmid. Both prevented the reduction in plaque size in the AVF group. To better define the mechanism of plaque regression in the AVF, we devised an endothelial cell (EC)-macrophage co-culture system where the ECs were exposed to high, low or no shear stress, and macrophages exposed to the EC effluent. There was a 2.5 fold increase in the migration of macrophages exposed to high shear effluent vs. low shear (p<0.05). This coincided with a 3-fold increase in the number of macrophages expressing activated β1 integrin in the high shear conditions. Uptake of apoptotic cells by macrophages was also 25% higher in the high shear vs. static (p<0.05). When repeated using the MMP inhibitor, GM6001, the high shear increase in migration was blocked in the presence of MMP inhibition; however, it had no effect on cell phagocytosis. Our findings suggest that shear stress acting on ECs may influence the cells within the plaque by increasing MMP activity allowing for better macrophage motility, an important feature of regressing plaques.

Known players, new interplay in atherogenesis: Chronic shear stress and carbamylated-LDL induce and modulate expression of atherogenic LR11 in human coronary artery endothelium

2014 ◽  
Vol 111 (02) ◽  
pp. 323-332 ◽  
Author(s):  
Eva-Theres Gensberger ◽  
Susanna Scharrer ◽  
Heinz Regele ◽  
Klaus Aumayr ◽  
Chantal Kopecky ◽  
...  
Keyword(s):  
Shear Stress ◽  
Coronary Artery ◽  
Ldl Receptor ◽  
Low Density ◽  
High Shear ◽  
High Shear Stress ◽  
Human Coronary Artery ◽  
Static Conditions

SummaryIn this study we examined whether low-density lipoprotein (LDL) receptor family members represent a link between blood flow characteristics and modified low-density lipoproteins involved in endothelial injury, a pivotal factor in atherogenesis. We demonstrated the expression of pro-atherogenic LDL receptor relative (LR11) for the first time in human coronary artery endothelial cells (HCAEC) in vitro and in vivo. Next, LR11 expression and regulation were explored in HCAEC cultured conventionally or on the inner surface of hollow fiber capillaries under exposure to shear stress for 10 days in the presence or absence of LDL. There was no LR11 expression under static conditions. When exposed to chronic low shear stress (2.5 dynes/cm2) transmembrane and soluble endothelial-LR11 were detected in high levels irrespective of the type of LDL added (carbamylated or native). In contrast, chronic high shear stress (25 dynes/cm2) inhibited the LR11-inducing effect of LDL such that transmembrane and soluble LR11 expression became non-detectable with native LDL. Carbamylated LDL significantly counteracted this atheroprotective effect of high shear stress as shown by lower, yet sustained expression of soluble and transmembrane LR11. Oxidised LDL showed similar effects compared to carbamylated LDL but caused significantly lower LR11 expression under chronic high shear stress. Medium from HCAEC under LR11-inducing conditions enhanced vascular smooth muscle cell migration, which was abrogated by the anti-LR11 antibody. Expression of LR11 depended entirely on p38MAPK phosphorylation. We conclude that coronary endothelial LR11 expression modulated by LDL and chronic shear stress contributes to atherogenesis. LR11 and p38MAPK are potential targets for prevention of atherosclerosis.

Astragaloside Attenuates Atherosclerosis Coupled Inflammation Through miR-101/Mitogen-Activated Protein Kinase Phosphatase-1 (MKP-1)/p38 Signaling in Mice

2021 ◽  
Vol 13 (9) ◽  
pp. 1666-1673
Author(s):  
Zhidong Chen ◽  
Kankai Tang ◽  
Wei Xu ◽  
Fengqi Liu ◽  
Bingnan Zhu ◽  
...  
Keyword(s):  
Protein Kinase ◽  
High Fat Diet ◽  
Mitogen Activated Protein Kinase ◽  
Inflammatory Factors ◽  
Atherosclerotic Plaques ◽  
High Fat ◽  
Mitogen Activated Protein ◽  
Stable Plaque ◽  
Hepatocyte Steatosis

This study aimed at elucidating the effect of astragaloside on atherosclerosis coupled inflammation and potential mechanism in mice. C57BL/6J mice were maintained in high-fat diet (HFD) for 12 weeks to induce atherosclerosis, with or without treatment with astragaloside (50 mg/kg). In turn, serum biochemical parameters in mice were also evaluated. Multiple tissue stain assay, including HE, were employed to assess the pathological alterations in arteries, and blood inflammation mediators were examined using ELISA. Expressions of microRNA101 (miR-101), p-p38 and mitogen-activated protein kinase phosphatase-1 (MKP-1) in the arteries were evaluated by qPCR and Western blot. Finally, AML-193 cells were transfected by miR-101 mimics and inhibitors. Expression of miR-101, MKP-1 and downstream inflammation cytokines were then analyzed. High-fat diet (HFD) mice with astragaloside treatment exhibited reduced atherosclerotic plaques size evaluated by oil red o, improved hepatocyte steatosis, and increased collagen fibers in atherosclerotic plaques for more stable plaque. Further, astragaloside treatment suppressed miR-101 transcription and enhanced MKP-1 expression, thus restraining the secretion of inflammation factors in vitro. Moreover, the inhibited impact of astragaloside in inflammatory factors production was ineffective in the presence of miR-101 mimics in AML-193 cells stimulated by LPS. Astragaloside exerted an anti-inflammatory role through miR-101/MKP-1/p38 signaling, for reducing atherosclerotic plaques and alleviate inflammation damage in mice and AML-193 cell.

scholarly journals High-Fat Diet Leads to Reduced Protein O-GlcNAcylation and Mitochondrial Defects Promoting the Development of Alzheimer’s Disease Signatures

2021 ◽  
Vol 22 (7) ◽  
pp. 3746
Author(s):  
Ilaria Zuliani ◽  
Chiara Lanzillotta ◽  
Antonella Tramutola ◽  
Eugenio Barone ◽  
Marzia Perluigi ◽  
...  
Keyword(s):  
Alzheimer’S Disease ◽  
Insulin Resistance ◽  
Alzheimer's Disease ◽  
High Fat Diet ◽  
Mitochondrial Activity ◽  
High Fat ◽  
Hexosamine Biosynthetic Pathway ◽  
Neurodegenerative Process ◽  
The Brain

The disturbance of protein O-GlcNAcylation is emerging as a possible link between altered brain metabolism and the progression of neurodegeneration. As observed in brains with Alzheimer’s disease (AD), flaws of the cerebral glucose uptake translate into reduced protein O-GlcNAcylation, which promote the formation of pathological hallmarks. A high-fat diet (HFD) is known to foster metabolic dysregulation and insulin resistance in the brain and such effects have been associated with the reduction of cognitive performances. Remarkably, a significant role in HFD-related cognitive decline might be played by aberrant protein O-GlcNAcylation by triggering the development of AD signature and mitochondrial impairment. Our data support the impairment of total protein O-GlcNAcylation profile both in the brain of mice subjected to a 6-week high-fat-diet (HFD) and in our in vitro transposition on SH-SY5Y cells. The reduction of protein O-GlcNAcylation was associated with the development of insulin resistance, induced by overfeeding (i.e., defective insulin signaling and reduced mitochondrial activity), which promoted the dysregulation of the hexosamine biosynthetic pathway (HBP) flux, through the AMPK-driven reduction of GFAT1 activation. Further, we observed that a HFD induced the selective impairment of O-GlcNAcylated-tau and of O-GlcNAcylated-Complex I subunit NDUFB8, thus resulting in tau toxicity and reduced respiratory chain functionality respectively, highlighting the involvement of this posttranslational modification in the neurodegenerative process.

scholarly journals Differential organ-specific inflammatory response to progranulin in high-fat diet-fed mice

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Maki Murakoshi ◽  
Tomohito Gohda ◽  
Eri Adachi ◽  
Saki Ichikawa ◽  
Shinji Hagiwara ◽  
...  
Keyword(s):  
Adipose Tissue ◽  
High Fat Diet ◽  
Kidney Injury ◽  
Proximal Tubules ◽  
Tubular Damage ◽  
Standard Diet ◽  
Mrna Levels ◽  
High Fat ◽  
Organ Specific

AbstractProgranulin (PGRN) has been reported to bind tumor necrosis factor (TNF) receptor and to inhibit TNFα signaling. We evaluated the effect of augmentation of TNFα signaling by PGRN deficiency on the progression of kidney injury. Eight-week-old PGRN knockout (KO) and wild-type (WT) mice were fed a standard diet or high-fat diet (HFD) for 12 weeks. Albuminuria, markers of tubular damage, and renal mRNA levels of inflammatory cytokines were higher in HFD-fed KO (KO-HFD) mice than in HFD-fed WT (WT-HFD) mice. Body weight, vacuolization in proximal tubules, and systemic and adipose tissue inflammatory markers were lower in the KO-HFD mice than in the WT-HFD mice. The renal megalin expression was lower in the KO mice than in the WT mice regardless of the diet type. The megalin expression was also reduced in mouse proximal tubule epithelial cells stimulated with TNFα and in those with PGRN knockdown by small interfering RNA in vitro. PGRN deficiency was associated with both exacerbated renal inflammation and decreased systemic inflammation, including that in the adipose tissue of mice with HFD-induced obesity. Improved tubular vacuolization in the KO-HFD mice might partially be explained by the decreased expression of megalin in proximal tubules.

Sequoyitol ameliorates diabetic nephropathy in diabetic rats induced with a high-fat diet and a low dose of streptozotocin

2014 ◽  
Vol 92 (5) ◽  
pp. 405-417 ◽  
Author(s):  
Xian-Wei Li ◽  
Yan Liu ◽  
Wei Hao ◽  
Jie-Ren Yang
Keyword(s):  
Diabetic Nephropathy ◽  
Blood Glucose ◽  
High Fat Diet ◽  
Low Dose ◽  
Serum Insulin ◽  
Fasting Blood Glucose ◽  
Diabetic Rats ◽  
High Fat

Sequoyitol decreases blood glucose, improves glucose intolerance, and enhances insulin signaling in ob/ob mice. The aim of this study was to investigate the effects of sequoyitol on diabetic nephropathy in rats with type 2 diabetes mellitus and the mechanism of action. Diabetic rats, induced with a high-fat diet and a low dose of streptozotocin, and were administered sequoyitol (12.5, 25.0, and 50.0 mg·(kg body mass)−1·d−1) for 6 weeks. The levels of fasting blood glucose (FBG), serum insulin, blood urea nitrogen (BUN), and serum creatinine (SCr) were measured. The expression levels of p22phox, p47phox, NF-κB, and TGF-β1 were measured using immunohistochemisty, real-time PCR, and (or) Western blot. The total antioxidative capacity (T-AOC), as well as the levels of malondialdehyde (MDA) and reactive oxygen species (ROS) were also determined. The results showed that sequoyitol significantly decreased FBG, BUN, and SCr levels, and increased the insulin levels in diabetic rats. The level of T-AOC was significantly increased, while ROS and MDA levels and the expression of p22phox, p47phox, NF-κB, and TGF-β1 were decreased with sequoyitol treatment both in vivo and in vitro. These results suggested that sequoyitol ameliorates the progression of diabetic nephropathy in rats, as induced by a high-fat diet and a low dose of streptozotocin, through its glucose-lowering effects, antioxidant activity, and regulation of TGF-β1 expression.

scholarly journals Aloe-Emodin Relieves High-Fat Diet Induced QT Prolongation via MiR-1 Inhibition and IK1 Up-Regulation in Rats

2017 ◽  
Vol 43 (5) ◽  
pp. 1961-1973 ◽  
Author(s):  
Yan Bai ◽  
Zhenli Su ◽  
Hanqi Sun ◽  
Wei Zhao ◽  
Xue Chen ◽  
...  
Keyword(s):  
Action Potential ◽  
Protein Expression ◽  
High Fat Diet ◽  
Qt Prolongation ◽  
Electrical Remodeling ◽  
High Fat ◽  
Treatment Groups ◽  
Aloe Emodin

Background/Aims: High-fat diet (HFD) causes cardiac electrical remodeling and increases the risk of ventricular arrhythmias. Aloe-emodin (AE) is an anthraquinone component isolated from rhubarb and has a similar chemical structure with emodin. The protective effect of emodin against cardiac diseases has been reported in the literature. However, the cardioprotective property of AE is still unknown. The present study investigated the effect of AE on HFD-induced QT prolongation in rats. Methods: Adult male Wistar rats were randomly divided into three groups: control, HFD, and AE-treatment groups. Normal diet was given to rats in the control group, high-fat diet was given to rats in HFD and AE-treatment groups for a total of 10 weeks. First, HFD rats and AE-treatment rats were fed with high-fat diet for 4 weeks to establish the HFD model. Serum total cholesterol and triglyceride levels were measured to validate the HFD model. Afterward, AE-treatment rats were intragastrically administered with 100 mg/kg AE each day for 6 weeks. Electrocardiogram monitoring and whole-cell patch-clamp technique were applied to examine cardiac electrical activity, action potential and inward rectifier K+ current (IK1), respectively. Neonatal rat ventricular myocytes (NRVMs) were subjected to cholesterol and/or AE. Protein expression of Kir2.1 was detected by Western blot and miR-1 level was examined by real-time PCR in vivo and in vitro, respectively. Results: In vivo, AE significantly shortened the QT interval, action potential duration at 90% repolarization (APD90) and resting membrane potential (RMP), which were markedly elongated by HFD. AE increased IK1 current and Kir2.1 protein expression which were reduced in HFD rats. Furthermore, AE significantly inhibited pro-arrhythmic miR-1 in the hearts of HFD rats. In vitro, AE decreased miR-1 expression levels resulting in an increase of Kir2.1 protein levels in cholesterol-enriched NRVMs. Conclusions: AE prevents HFD-induced QT prolongation by repressing miR-1 and upregulating its target Kir2.1. These findings suggest a novel pharmacological role of AE in HFD-induced cardiac electrical remodeling.

scholarly journals 7-Hydroxymatairesinol improves body weight, fat and sugar metabolism in C57BJ/6 mice on a high-fat diet

2018 ◽  
Vol 120 (7) ◽  
pp. 751-762 ◽  
Author(s):  
Giorgio Biasiotto ◽  
Isabella Zanella ◽  
Federica Predolini ◽  
Ivonne Archetti ◽  
Moris Cadei ◽  
...  
Keyword(s):  
Metabolic Syndrome ◽  
Body Weight ◽  
High Fat Diet ◽  
Sugar Metabolism ◽  
Lipid Uptake ◽  
High Fat ◽  
Total Extract ◽  
The Metabolic Syndrome ◽  
Metabolic Genes

Abstract7-Hydroxymatairesinol (7-HMR) is a plant lignan abundant in various concentrations in plant foods. The objective of this study was to test HMRLignan™, a purified form of 7-HMR, and the correspondingPicea abiesextract (total extractP. abies; TEP) as dietary supplements on a background of a high-fat diet (HFD)-induced metabolic syndrome in mice and in the 3T3-L1 adipogenesis model. Mice, 3 weeks old, were fed a HFD for 60 d. Subgroups were treated with 3 mg/kg body weight 7-HMR (HMRLignan™) or 10 mg/kg body weight TEP by oral administration. 7-HMR and TEP limited the increase in body weight (−11 and −13 %) and fat mass (−11 and −18 %) in the HFD-fed mice. Epididymal adipocytes were 19 and −12 % smaller and the liver was less steatotic (−62 and −65 %). Serum lipids decreased in TEP-treated mice (−11 % cholesterol, −23 % LDL and −15 % TAG) and sugar metabolism was ameliorated by both lignan preparations, as shown by a more than 70 % decrease in insulin secretion and insulin resistance. The expression of several metabolic genes was modulated by the HFD with an effect that was reversed by lignan. In 3T3-L1 cells, the 7-HMR metabolites enterolactone (ENL) and enterodiol (END) showed a 40 % inhibition of cell differentiation accompanied by the inhibited expression of the adipogenic genesPPARγ,C/EBPαandaP2. Furthermore, END and ENL caused a 10 % reduction in TAG uptake in HEPA 1–6 hepatoma cells. In conclusion, 7-HMR and TEP reduce metabolic imbalances typical of the metabolic syndrome and obesity in male mice, whereas their metabolites inhibit adipogenesis and lipid uptakein vitro.

Cholate inhibits high-fat diet-induced hyperglycemia and obesity with acyl-CoA synthetase mRNA decrease

1997 ◽  
Vol 273 (1) ◽  
pp. E37-E45 ◽  
Author(s):  
S. Ikemoto ◽  
M. Takahashi ◽  
N. Tsunoda ◽  
K. Maruyama ◽  
H. Itakura ◽  
...  
Keyword(s):  
High Fat Diet ◽  
Skeletal Muscles ◽  
Unsaturation Index ◽  
Sodium Cholate ◽  
Fat Absorption ◽  
High Fat ◽  
Cholesterol Accumulation ◽  
Triglyceride Accumulation ◽  
Responsive Element

The effects of sodium cholate on high-fat diet-induced hyperglycemia and obesity were investigated. Insulin resistance was estimated by measuring 2-deoxyglucose uptake in epitrochlearis muscles incubated in vitro. Addition of 0.5% cholate to high-safflower oil diet completely prevented high fat-induced hyperglycemia and obesity in C57BL/6J mice with a slight decrease of energy intake but with no inhibition of fat absorption. Furthermore, the addition of cholate decreased blood insulin levels and prevented high-fat diet-induced decrease of glucose uptake in epitrochlearis. However, there was no change in the unsaturation index of fatty acids in skeletal muscles and in GLUT-4 levels by cholate. In liver, cholate addition resulted in cholesterol accumulation and completely prevented high-fat diet-induced triglyceride accumulation. The changes of triglyceride level in the liver were paralleled to the changes of acyl-CoA synthetase (ACS) mRNA. ACS catalyzes the formation of acyl-CoA from fatty acid, and acyl-CoA is utilized for triglyceride formation in liver. ACS has a sterol-responsive element 1 in its promoter region. These data indicate that the favorable effects of cholate could be partly the result of downregulation of ACS mRNA.

scholarly journals Hepatic Lipid Accumulation Induced by a High-fat Diet Is Regulated by Nrf2 Through Multiple Pathways

2021 ◽  
Author(s):  
sheng Qiu ◽  
Zerong Liang ◽  
Qinan Wu ◽  
Miao Wang ◽  
Mengliu Yang ◽  
...  
Keyword(s):  
Lipid Metabolism ◽  
Lipid Accumulation ◽  
High Fat Diet ◽  
Underlying Mechanism ◽  
Luciferase Assay ◽  
High Fat ◽  
Hepatic Lipid ◽  
Hepatic Lipid Accumulation

Abstract BackgroundNuclear factor erythroid 2-related factor 2 (Nrf2) is reportedly involved in hepatic lipid metabolism, but the results are contradictory and the underlying mechanism thus remains unclear. Herein we focused on elucidating the effects of Nrf2 on hepatic adipogenesis and on determining the possible underlying mechanism. We established a metabolic associated fatty liver disease (MAFLD) model in high fat diet (HFD) fed Nrf2 knockout (Nrf2 KO) mice; further, a cell model of lipid accumulation was established using mouse primary hepatocytes (MPHs) treated with free fatty acids (FAs). Using these models, we investigated the relationship between Nrf2 and autophagy and its role in the development of MAFLD.ResultsWe observed that Nrf2 expression levels were up-regulated in patients with MAFLD and diet-induced obese mice. Nrf2 deficiency led to hepatic lipid accumulation in vivo and in vitro, in addition to, promoting lipogenesis mainly by increasing SREBP-1 activity. Moreover, Nrf2 deficiency attenuated autophagic flux and inhibited the fusion of autophagosomes and lysosomes in vivo and in vitro. Weakened autophagy caused reduced lipolysis in the liver. Importantly, Chromatin immunoprecipitation-qPCR (ChIP-qPCR) and dual-luciferase assay results proved that Nrf2 bound to LAMP1 promoter and regulated its transcriptional activity. We accordingly report that Nrf2-LAMP1 interaction has an indispensable role in Nrf2-regulated hepatosteatosis. ConclusionsThese data collectively confirm that Nrf2 deficiency promotes hepatosteatosis by enhancing SREBP-1 activity and attenuating autophagy. To conclude, our data reveal a novel multi-pathway effect of Nrf2 on lipid metabolism in the liver, and we believe that multi-target intervention of Nrf2 signaling is a promising new strategy for the prevention and treatment of MAFLD.

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