Hesperetin inhibits foam cell formation in macrophages via activating LXRα signal in an AMPK dependent manner

AbstractCholesterol efflux from macrophages is the first step of cholesterol reverse transport (RCT), whose increase inhibits cholesterol accumulation and foam cell formation to suppress atherogenesis. Liver X receptor alpha (LXRα) and adenosine monophosphate activated protein kinases (AMPK) both have the pivotal role in cholesterol homeostasis. However the association between these two molecules in cell model of atherosclerosis is poorly understood. Hesperetin has been reported to possess several protective effects for cardiovascular diseases, while little is known about the role of hesperetin and its underlying mechanism on macrophage foam cell formation. In this study, we sought to investigate the potential effects of hesperetin in cholesterol efflux by using human macrophage derived foam cells, focusing on liver X receptor alpha (LXRα) and adenosine monophosphate activated protein kinases (AMPK) implication. Hesperetin treatment concentration-dependently reduced foam cell formation, intracellular cholesterol level and cholesterol esterification rate, and enhanced cholesterol efflux in THP-1 macrophages. Hesperetin upregulated the protein levels of LXRα and its targets including ABCA1, ABCG1 as well as SR-BI, and phosphorylated-AMPK. Meanwhile, hesperetin-induced upregulation of LXRα expression was enhanced by AMPK agonist and inhibited by AMPK inhibitor. Furthermore, hesperetin increased mRNA level of LXRα and its target genes, all which were depressed by AMPKα1/α2 small interfering RNA (siRNA) transfection. In conclusion, we founded for the first time that hesperetin could active AMPK. And this activation upregulated LXRα and its targets including ABCA1, ABCG1 and SR-BI, which significantly inhibited foam cell formation and promoted cholesterol efflux in THP-1 macrophages. Our results highlight the therapeutic potential of hespretin for the possible reduction in foam cell formation. This new mechanism could contribute the anti-atherogenic effects of hesperetin.

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Retinoic acid induces macrophage cholesterol efflux and inhibits atherosclerotic plaque formation in apoE-deficient mice

British Journal Of Nutrition ◽

10.1017/s0007114515002159 ◽

2015 ◽

Vol 114 (4) ◽

pp. 509-518 ◽

Cited By ~ 20

Author(s):

Wenjing Zhou ◽

Jiacheng Lin ◽

Hongen Chen ◽

Jingjing Wang ◽

Yan Liu ◽

...

Keyword(s):

Retinoic Acid ◽

Protein Expression ◽

Cholesterol Efflux ◽

Foam Cell ◽

Cell Formation ◽

Peritoneal Macrophages ◽

Foam Cell Formation ◽

Control Group ◽

Dependent Manner ◽

Dose Dependent

It has been suggested that retinoic acid (RA) has a potential role in the prevention of atherosclerotic CVD. In the present study, we used J774A.1 cell lines and primary peritoneal macrophages to investigate the protective effects of RA on foam cell formation and atherogenesis in apoE-deficient (apoE− / −) mice. A total of twenty male apoE− / − mice (n 10 animals per group), aged 8 weeks, were fed on a high-fat diet (HFD) and treated with vehicle or 9-cis-RA for 8 weeks. The atherosclerotic plaque area in the aortic sinus of mice in the 9-cis-RA group was 40·7 % less than that of mice in the control group (P< 0·01). Mouse peritoneal macrophages from the 9-cis-RA group had higher protein expression levels of ATP-binding cassette transporter A1 (ABCA1) and G1 (ABCG1) than those from the control group. Serum total and LDL-cholesterol concentrations were lower in the 9-cis-RA group than in the control group (P< 0·05). In vitro studies showed that incubation of cholesterol-loaded J774A.1 macrophages with 9-cis-RA (0·1, 1 and 10 μmol/l) induced cholesterol efflux in a dose-dependent manner. The 9-cis-RA treatment markedly attenuated lipid accumulation in macrophages exposed to oxidised LDL. Moreover, treatment with 9-cis-RA significantly increased the protein expression levels of ABCA1 and ABCG1 in J774A.1 macrophages in a dose-dependent manner. Furthermore, 9-cis-RA dose-dependently enhanced the protein expression level of liver X receptor-α (LXRα), the upstream regulator of ABCA1 and ABCG1. Taken together, the present results show that 9-cis-RA suppresses foam cell formation and prevents HFD-induced atherogenesis via the LXRα-dependent up-regulation of ABCA1 and ABCG1.

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RIP140 triggers foam-cell formation by repressing ABCA1/G1 expression and cholesterol efflux via liver X receptor

FEBS Letters ◽

10.1016/j.febslet.2015.01.001 ◽

2015 ◽

Vol 589 (4) ◽

pp. 455-460 ◽

Cited By ~ 5

Author(s):

Yanhong He ◽

Luankun Zhang ◽

Zhuoming Li ◽

Hui Gao ◽

Zhongbao Yue ◽

...

Keyword(s):

Cholesterol Efflux ◽

Foam Cell ◽

Cell Formation ◽

Liver X Receptor ◽

Foam Cell Formation

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Hesperetin inhibits foam cell formation and promotes cholesterol efflux in THP-1-derived macrophages by activating LXRα signal in an AMPK-dependent manner

Journal of Physiology and Biochemistry ◽

10.1007/s13105-020-00783-9 ◽

2021 ◽

Author(s):

Xuanjing Chen ◽

Dezhi Zou ◽

Xiaoling Chen ◽

Huanlin Wu ◽

Danping Xu

Keyword(s):

Cholesterol Efflux ◽

Target Genes ◽

Therapeutic Potential ◽

Foam Cell ◽

Cell Formation ◽

Underlying Mechanism ◽

Foam Cell Formation ◽

Dependent Manner ◽

Protective Effects ◽

Macrophage Foam Cell

AbstractCholesterol efflux from macrophages is the first step of reverse cholesterol transport (RCT), whose increase inhibits cholesterol accumulation and foam cell formation to suppress atherogenesis. Hesperetin has been reported to exert several protective effects on cardiovascular diseases, while little is known about the role of hesperetin and its underlying mechanism in macrophage foam cell formation. In this study, we sought to investigate the potential effects of hesperetin on foam cell formation and cholesterol efflux by using human macrophages, focusing on liver X receptor alpha (LXRα) and AMPK. We found that hesperetin treatment reduced foam cell formation, intracellular cholesterol levels and the cholesterol esterification rate, and increased cholesterol efflux in THP-1 macrophages. Hesperetin increased the levels of LXRα protein and its targets, including ABCA1, ABCG1, SR-BI, and phosphorylated-AMPK. Meanwhile, the hesperetin-induced increase in LXRα expression was further increased by the AMPK agonist and inhibited by an AMPK inhibitor. Meanwhile, hesperetin increased the levels of LXRα mRNA and its target genes, all of which were decreased in cells transfected with the AMPKα1/α2 small interfering RNA (siRNA). Furthermore, the hesperetin-induced inhibition of foam cell formation and promotion of cholesterol efflux were decreased by transfection of AMPKα1/α2 siRNA. In conclusions, We are the first to report that hesperetin activate AMPK in THP-1-derived macrophages. This activation upregulats LXRα and its targets, including ABCA1, ABCG1 and SR-BI, which significantly inhibits foam cell formation and promotes cholesterol efflux. Our results highlight the therapeutic potential of hesperetin to possibly reduce foam cell formation. This new mechanism might contribute the anti-atherogenic effects of hesperetin.

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The Anti-Atherogenic Properties of Sesamin are Mediated via Improved Macrophage Cholesterol Efflux Through PPARγ1-LXRα and MAPK Signaling

International Journal for Vitamin and Nutrition Research ◽

10.1024/0300-9831/a000195 ◽

2014 ◽

Vol 84 (1-2) ◽

pp. 79-91 ◽

Cited By ~ 7

Author(s):

Amin F. Majdalawieh ◽

Hyo-Sung Ro

Keyword(s):

Cholesterol Efflux ◽

Transcriptional Activity ◽

Molecular Mechanisms ◽

Foam Cell ◽

Mapk Signaling ◽

Luciferase Reporter ◽

Foam Cell Formation ◽

Dependent Manner ◽

Concentration Dependent Manner ◽

Macrophage Cholesterol Efflux

Background: Foam cell formation resulting from disrupted macrophage cholesterol efflux, which is triggered by PPARγ1 and LXRα, is a hallmark of atherosclerosis. Sesamin and sesame oil exert anti-atherogenic effects in vivo. However, the exact molecular mechanisms underlying such effects are not fully understood. Aim: This study examines the potential effects of sesamin (0, 25, 50, 75, 100 μM) on PPARγ1 and LXRα expression and transcriptional activity as well as macrophage cholesterol efflux. Methods: PPARγ1 and LXRα expression and transcriptional activity are assessed by luciferase reporter assays. Macrophage cholesterol efflux is evaluated by ApoAI-specific cholesterol efflux assays. Results: The 50 μM, 75 μM, and 100 μM concentrations of sesamin up-regulated the expression of PPARγ1 (p< 0.001, p < 0.001, p < 0.001, respectively) and LXRα (p = 0.002, p < 0.001, p < 0.001, respectively) in a concentration-dependent manner. Moreover, 75 μM and 100 μM concentrations of sesamin led to 5.2-fold (p < 0.001) and 6.0-fold (p<0.001) increases in PPAR transcriptional activity and 3.9-fold (p< 0.001) and 4.2-fold (p < 0.001) increases in LXR transcriptional activity, respectively, in a concentration- and time-dependent manner via MAPK signaling. Consistently, 50 μM, 75 μM, and 100 μM concentrations of sesamin improved macrophage cholesterol efflux by 2.7-fold (p < 0.001), 4.2-fold (p < 0.001), and 4.2-fold (p < 0.001), respectively, via MAPK signaling. Conclusion: Our findings shed light on the molecular mechanism(s) underlying sesamins anti-atherogenic effects, which seem to be due, at least in part, to its ability to up-regulate PPARγ1 and LXRα expression and transcriptional activity, improving macrophage cholesterol efflux. We anticipate that sesamin may be used as a therapeutic agent for treating atherosclerosis.

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Abstract 43: Cholesterol Efflux Pathways Suppress Inflammasome Activation in Mice and Humans

Arteriosclerosis Thrombosis and Vascular Biology ◽

10.1161/atvb.37.suppl_1.43 ◽

2017 ◽

Vol 37 (suppl_1) ◽

Author(s):

Marit Westerterp ◽

Panagiotis Fotakis ◽

Mireille Ouimet ◽

Andrea E Bochem ◽

Hanrui Zhang ◽

...

Keyword(s):

Plasma Levels ◽

Cholesterol Efflux ◽

Foam Cell ◽

Cell Formation ◽

Density Lipoprotein ◽

Foam Cell Formation ◽

Inflammasome Activation ◽

Loss Of Function ◽

Caspase 1 ◽

Macrophage Cholesterol Efflux

Plasma high-density-lipoprotein (HDL) has several anti-atherogenic properties, including its key role in functioning as acceptor for ATP-binding cassette A1 and G1 (ABCA1 and ABCG1) mediated cholesterol efflux. We have shown previously that macrophage Abca1/g1 deficiency accelerates atherosclerosis, by enhancing foam cell formation and inflammatory cytokine expression in atherosclerotic plaques. Macrophage cholesterol accumulation activates the inflammasome, leading to caspase-1 cleavage, required for IL-1β and IL-18 secretion. Several studies have suggested that inflammasome activation accelerates atherogenesis. We hypothesized that macrophage Abca1/g1 deficiency activates the inflammasome. In Ldlr -/- mice fed a Western type diet (WTD), macrophage Abca1/g1 deficiency increased IL-1β and IL-18 plasma levels (2-fold; P <0.001), and induced caspase-1 cleavage. Deficiency of the inflammasome components Nlrp3 or caspase-1 in macrophage Abca1/g1 knockouts reversed the increase in plasma IL-18 levels ( P <0.001), indicating these changes were inflammasome dependent. We found that macrophage Abca1/g1 deficiency induced caspase-1 cleavage in splenic CD115 + monocytes and CD11b + macrophages. While mitochondrial ROS production or lysosomal function were not affected, macrophage Abca1/g1 deficiency led to an increased splenic population of monocytes (2.5-fold; P <0.01). Monocytes secrete ATP, and as a result, ATP secretion from total splenic cells was increased (2.5-fold; P <0.01), likely contributing to inflammasome activation. Caspase-1 deficiency decreased atherosclerosis in macrophage Abca1/g1 deficient Ldlr -/- mice fed WTD for 8 weeks (225822 vs 138606 μm 2 ; P <0.05). Of therapeutic interest, one injection of reconstituted HDL (100 mg/kg) in macrophage Abca1/g1 knockouts decreased plasma IL-18 levels ( P <0.05). Tangier disease patients, with a homozygous loss-of-function for ABCA1, showed increased IL-1β and IL-18 plasma levels (3-fold; P <0.001), suggesting that cholesterol efflux pathways also suppress inflammasome activation in humans. These findings suggest that macrophage cholesterol efflux pathways suppress inflammasome activation, possibly contributing to the anti-atherogenic effects of HDL treatment.

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Niacin‐induced enhancement of lysosomal cholesterol efflux in macrophages through CD38 ‐ NAADP signaling pathway: implication in reduced foam cell formation (671.6)

The FASEB Journal ◽

10.1096/fasebj.28.1_supplement.671.6 ◽

2014 ◽

Vol 28 (S1) ◽

Author(s):

Fan Zhang ◽

Qiufang Zhang ◽

Ningjun Li ◽

Pin‐Lan Li

Keyword(s):

Signaling Pathway ◽

Cholesterol Efflux ◽

Foam Cell ◽

Cell Formation ◽

Foam Cell Formation

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Abstract 57: The Epigenetic Enzyme Kdm6b Controls the Pro-Fibrotic Transcriptome Signature of Foam Cells

Arteriosclerosis Thrombosis and Vascular Biology ◽

10.1161/atvb.37.suppl_1.57 ◽

2017 ◽

Vol 37 (suppl_1) ◽

Author(s):

Annette E Neele ◽

Koen H Prange ◽

Marten A Hoeksema ◽

Saskia van der Velden ◽

Tina Lucas ◽

...

Keyword(s):

Foam Cell ◽

Smooth Muscle Actin ◽

Cell Formation ◽

Atherosclerotic Lesion ◽

Foam Cells ◽

Foam Cell Formation ◽

Cell Phenotype ◽

Sequencing Analysis ◽

Dependent Manner ◽

Alpha Smooth Muscle Actin

Aim: Foam cells are a key hallmark of atherosclerotic lesion formation. Within the atherosclerotic lesion macrophages scavenge modified lipoproteins and thereby acquire their foam cell characteristics. Besides their foam cell phenotype, macrophages can have specific inflammation regulatory functions in atherosclerotic lesions. Epigenetic pathways are crucial for monocyte to macrophage differentiation and activation. The H3K27 demethylase Kdm6b (also known as Jmjd3) is regulated in response to various triggers and regulates several modes of macrophage activation. Given the crucial role of macrophage foam cells in atherosclerosis, we here studied Kdm6b in peritoneal foam cells in order to identify regulated pathways. Material and Methods: A myeloid deficient Kdm6b mice (LysMCre-Kdm6b fl/fl ) was generated and bone marrow of Kdm6b wt or Kdm6b del mice was transplanted to irradiated Ldlr -/- mice which were fed a high fat diet for 9 weeks to induce foam cell formation. Peritoneal foam cells from Kdm6b del or Kdm6b wt mice were isolated and used for RNA-sequencing analysis. Results: Among the list of downregulated genes many genes involving fibrosis were affected in Kdm6b deficient foam cells including Collagen genes ( Col1a1 , Col1a2 ), Alpha smooth muscle actin ( Acta2 ) and Fibronectin-1 ( Fn1 ). Pathway analysis on downregulated genes ( P -value < 0.05) indicated that pathways involved in epithelial to mesenchymaltransition (EMT) ( q- value=10 -13 ) and extracellular matrix organization ( q- value=10 -4 ) were significantly downregulated. Pro-fibrotic pathways were thus strongly suppressed in Kdm6b deleted foam cells. Analysis of published datasets of foam cells showed that foam cell formation induces these pro-fibrotic characteristics. Overlay of both data sets indicated that fibrotic genes which are induced upon foam cell formation, are reduced in the absence of Kdm6b. These data suggest that foam cell formation induces a pro-fibrotic gene signature in a Kdm6b-dependent manner. Conclusion: We identified Kdm6b as a novel regulator of the pro-fibrotic signature of peritoneal foam cells.

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