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Sample records for macrophage cholesterol accumulation

  1. LDL Receptor-Related Protein-1 (LRP1 Regulates Cholesterol Accumulation in Macrophages.

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    Anna P Lillis

    Full Text Available Within the circulation, cholesterol is transported by lipoprotein particles and is taken up by cells when these particles associate with cellular receptors. In macrophages, excessive lipoprotein particle uptake leads to foam cell formation, which is an early event in the development of atherosclerosis. Currently, mechanisms responsible for foam cell formation are incompletely understood. To date, several macrophage receptors have been identified that contribute to the uptake of modified forms of lipoproteins leading to foam cell formation, but the in vivo contribution of the LDL receptor-related protein 1 (LRP1 to this process is not known [corrected]. To investigate the role of LRP1 in cholesterol accumulation in macrophages, we generated mice with a selective deletion of LRP1 in macrophages on an LDL receptor (LDLR-deficient background (macLRP1-/-. After feeding mice a high fat diet for 11 weeks, peritoneal macrophages isolated from Lrp+/+ mice contained significantly higher levels of total cholesterol than those from macLRP1-/- mice. Further analysis revealed that this was due to increased levels of cholesterol esters. Interestingly, macLRP1-/- mice displayed elevated plasma cholesterol and triglyceride levels resulting from accumulation of large, triglyceride-rich lipoprotein particles in the circulation. This increase did not result from an increase in hepatic VLDL biosynthesis, but rather results from a defect in catabolism of triglyceride-rich lipoprotein particles in macLRP1-/- mice. These studies reveal an important in vivo contribution of macrophage LRP1 to cholesterol homeostasis.

  2. Overexpressed PLTP in macrophage may promote cholesterol accumulation by prolonged endoplasmic reticulum stress.

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    Yang, Xinquan; Yu, Yang; Wang, Daxin; Qin, Shucun

    2017-01-01

    It is well known that phospholipid transfer protein (PLTP) is involved in the lipid metabolism and development of atherosclerosis (AS). Abundant PLTP is considered to be expressed on the foam cells derived from monocyte/macrophages in atherosclerotic plaques, suggesting that high level of active PLTP may promote the formation of foam cells. However, the exact role of PLTP on the process of macrophage derived foam cell formation remains unclear. The accumulation of free cholesterol (FC) in the cytoplasm may lead to the prolonged endoplasmic reticulum stress (ERs) and the imbalance of intracellular cholesterol homeostasis. Different PLTP level definitely alternates the phospholipids (PL) and cholesterol level in plasma, strongly suggesting that active PLTP may change the level of FC and PL intracellularly, which subsequently induced the ERs in macrophage. Thus, we hypothesize that high level of PLTP may promote the accumulation of cholesterol in macrophage via the alteration ratio of FC to PL. Therefore, validating this hypothesis may clarify the role of PLTP in macrophage ERs in AS and also raise a novel strategy in the regression of AS plaques via restoring intracellular membrane lipid homeostasis and attenuating ERs. Copyright © 2016 Elsevier Ltd. All rights reserved.

  3. Paraoxsonase2 (PON2) and oxidative stress involvement in pomegranate juice protection against cigarette smoke-induced macrophage cholesterol accumulation.

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    Rom, Oren; Aviram, Michael

    2016-11-25

    Exposure to cigarette smoke (CS) promotes various stages of atherosclerosis development. Macrophages are the predominant cells in early atherogenesis, and the polyphenolic-rich pomegranate juice (PJ) is known for its protective role against macrophage atherogenicity. The aim of the current study was to examine the atherogenic effects of CS on macrophages, and to evaluate the protective effects of PJ against CS-induced macrophage atherogenicity. Murine J774A.1 macrophages were treated with CS-exposed medium in the absence or presence of PJ. Parameters of lipid peroxidation in CS-exposed medium were measured by the lipid peroxides and thiobarbituric acid reactive substances (TBARS) assays. Atherogenicity of macrophages incubated with increasing concentrations of CS-exposed medium was assessed by cytotoxicity, oxidative stress determined by generation of reactive oxygen species (ROS) using DCFH-DA, activity of the cellular anti-oxidant paraoxonase2 (PON2), macrophage accumulation of cholesterol and triglycerides, as well as through high density lipoprotein (HDL)-mediated cholesterol efflux from the cells. CS exposure resulted in significant and dose-dependent increases in lipid peroxides and TBARS medium levels (up to 3 and 8-fold, respectively). Incubation of macrophages with CS-exposed medium resulted in dose-dependent increases in macrophage damage/injury (up to 6-fold), intracellular ROS levels (up to 31%), PON2 activity (up to 2-fold), and macrophage cholesterol content (up to 24%). The latter might be explained by reduced HDL-mediated cholesterol efflux from CS-exposed macrophages (by 21%). PJ protected macrophages from CS-induced increases in intracellular ROS levels and cholesterol accumulation, as well as the attenuated efflux of cholesterol. These data indicate that CS stimulates macrophage oxidation and activates PON2 as a possible compensatory response to the oxidative burden. CS impairs HDL-mediated cholesterol efflux from macrophages leading to cellular

  4. Uptake of dexamethasone incorporated into liposomes by macrophages and foam cells and its inhibitory effect on cellular cholesterol ester accumulation.

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    Chono, Sumio; Morimoto, Kazuhiro

    2006-09-01

    To confirm the efficacy of dexamethasone incorporated into liposomes in the treatment of atherosclerosis, the uptake of dexamethasone-liposomes by macrophages and foam cells and its inhibitory effect on cellular cholesterol ester accumulation in these cells were investigated in-vitro. Dexamethasone-liposomes were prepared with egg yolk phosphatidylcholine, cholesterol and dicetylphosphate in a lipid molar ratio of 7/2/1 by the hydration method. This was adjusted to three different particle sizes to clarify the influence of particle size on the uptake by the macrophages and foam cells, and the inhibitory effect on cellular cholesterol ester accumulation. The distribution of particle sizes of dexamethasone-liposomes were 518.7+/-49.5 nm (L500), 202.2+/-23.1 nm (L200), and 68.6+/-6.5 nm (L70), respectively. For each size, dexamethasone concentration and dexamethasone/lipid molar ratio in dexamethasone-liposome suspension were 1 mg dexamethasone mL-1 and 0.134 mol dexamethasone mol-1 total lipids, respectively. The zeta potential was approximately -70 mV for all sizes. Dexamethasone-liposomes or free dexamethasone were added to the macrophages in the presence of oxidized low density lipoprotein (oxLDL) and foam cells, and then incubated at 37 degrees C. The uptake amount of dexamethasone by the macrophages and foam cells after a 24-h incubation was L500>L200>free dexamethasone>L70. The macrophages in the presence of oxLDL and foam cells were incubated with dexamethasone-liposomes or free dexamethasone for 24 h at 37 degrees C to evaluate the inhibitory effect on the cellular cholesterol ester accumulation. The cellular cholesterol ester level in the macrophages treated with oxLDL was significantly increased compared with that in macrophages without additives. L500, L200 and free dexamethasone significantly inhibited this cholesterol ester accumulation. L500, L200 and free dexamethasone also significantly reduced cellular cholesterol ester accumulation in foam cells. In

  5. Cholesterol-induced inflammation and macrophage accumulation in adipose tissue is reduced by a low carbohydrate diet in guinea pigs.

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    Aguilar, David; deOgburn, Ryan C; Volek, Jeff S; Fernandez, Maria Luz

    2014-12-01

    The main objective of this study was to evaluate the effects of a high cholesterol (HC) dietary challenge on cholesterol tissue accumulation, inflammation, adipocyte differentiation, and macrophage infiltration in guinea pigs. A second objective was to assess whether macronutrient manipulation would reverse these metabolic alterations. Male Hartley guinea pigs (10/group) were assigned to either low cholesterol (LC) (0.04g/100g) or high cholesterol (HC) (0.25g/100g) diets for six weeks. For the second experiment, 20 guinea pigs were fed the HC diet for six weeks and then assigned to either a low carbohydrate (CHO) diet (L-CHO) (10% energy from CHO) or a high CHO diet (H-CHO) (54% CHO) for an additional six weeks. Higher concentrations of total (P adipose tissue and aortas of guinea pigs fed the HC compared to those in the LC group. In addition, higher concentrations of pro-inflammatory cytokines in the adipose tissue (P adipocytes in the HC group were smaller in size (P adipose and aortas as well as lower concentrations of inflammatory cytokines in adipose tissue were observed in the L-CHO group (P adipose cells and lower macrophage infiltration compared to the H-CHO group. The results of this study strongly suggest that HC induces metabolic dysregulation associated with inflammation in adipose tissue and that L-CHO is more effective than H-CHO in attenuating these detrimental effects.

  6. Mycobacterium leprae intracellular survival relies on cholesterol accumulation in infected macrophages: a potential target for new drugs for leprosy treatment

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    Mattos, Katherine A; Oliveira, Viviane C G; Berrêdo-Pinho, Marcia; Amaral, Julio J; Antunes, Luis Caetano M; Melo, Rossana C N; Acosta, Chyntia C D; Moura, Danielle F; Olmo, Roberta; Han, Jun; Rosa, Patricia S; Almeida, Patrícia E; Finlay, B Brett; Borchers, Christoph H; Sarno, Euzenir N; Bozza, Patricia T; Atella, Georgia C; Pessolani, Maria Cristina V

    2014-01-01

    We recently showed that Mycobacterium leprae (ML) is able to induce lipid droplet formation in infected macrophages. We herein confirm that cholesterol (Cho) is one of the host lipid molecules that accumulate in ML-infected macrophages and investigate the effects of ML on cellular Cho metabolism responsible for its accumulation. The expression levels of LDL receptors (LDL-R, CD36, SRA-1, SR-B1, and LRP-1) and enzymes involved in Cho biosynthesis were investigated by qRT-PCR and/or Western blot and shown to be higher in lepromatous leprosy (LL) tissues when compared to borderline tuberculoid (BT) lesions. Moreover, higher levels of the active form of the sterol regulatory element-binding protein (SREBP) transcriptional factors, key regulators of the biosynthesis and uptake of cellular Cho, were found in LL skin biopsies. Functional in vitro assays confirmed the higher capacity of ML-infected macrophages to synthesize Cho and sequester exogenous LDL-Cho. Notably, Cho colocalized to ML-containing phagosomes, and Cho metabolism impairment, through either de novo synthesis inhibition by statins or depletion of exogenous Cho, decreased intracellular bacterial survival. These findings highlight the importance of metabolic integration between the host and bacteria to leprosy pathophysiology, opening new avenues for novel therapeutic strategies to leprosy. PMID:24552180

  7. ACAT1 deficiency increases cholesterol synthesis in mouse peritoneal macrophages.

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    Dove, Dwayne E; Su, Yan Ru; Swift, Larry L; Linton, MacRae F; Fazio, Sergio

    2006-06-01

    Acyl-coenzyme A:cholesterol acyltransferase (ACAT) esterifies free cholesterol and stores cholesteryl esters in lipid droplets. Macrophage ACAT1 deficiency results in increased atherosclerotic lesion area in hyperlipidemic mice via disrupted cholesterol efflux, increased lipoprotein uptake, accumulation of intracellular vesicles, and accelerated apoptosis. The objective of this study was to determine whether lipid synthesis is affected by ACAT1. The synthesis, esterification, and efflux of new cholesterol were measured in peritoneal macrophages from ACAT1(-/-) mice. Cholesterol synthesis was increased by 134% (p=0.001) in ACAT1(-/-) macrophages compared to wildtype macrophages. Increased synthesis resulted in a proportional increase in the efflux of newly synthesized cholesterol. Although the esterification of new cholesterol was reduced by 93% (pSREBP1a mRNA was increased 6-fold in ACAT1(-/-) macrophages compared to wildtype macrophages, suggesting an up-regulation of cholesterol and fatty acid synthesis in ACAT1(-/-) macrophages. Increased cholesterol synthesis and up-regulation of SREBP in ACAT1(-/-) macrophages suggests that ACAT1 affects the regulation of lipid metabolism in macrophages. This change in cholesterol homeostasis may contribute to the atherogenic potential of ACAT1(-/-) macrophages.

  8. Inhibitory effect of Piper betel leaf extracts on copper-mediated LDL oxidation and oxLDL-induced lipid accumulation via inducing reverse cholesterol transport in macrophages.

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    Ma, Gwo-Chin; Wu, Pei-Fang; Tseng, Hsien-Chun; Chyau, Charng-Cherng; Lu, Hsiu-Chin; Chou, Fen-Pi

    2013-12-15

    Piper betel leaf (PBL) has the biological capabilities of detoxification and can work as an anti-inflammatory agent and an anti-oxidant. In this study, we evaluated the anti-oxidative activity of the extract of Piper betel leaves (PBLs) on the basis of Cu(2+)-mediated oxidation, and its ability to prevent foam cell formation in a model for oxidised low density lipoprotein (oxLDL)-induced lipid accumulation in macrophages. Our data demonstrated that PBLs were able to inhibit LDL oxidation in vitro and are able to reduce the lipid accumulation in macrophages. We showed the underlying mechanisms to be the following: PBLs up-regulated the protein levels of the class A and class B scavenger receptors, the membrane lipid transporter ABCA1, and its upstream regulator Liver X receptor (LXR) in the macrophages exposed to oxLDL. The results suggested that PBLs activated the reverse cholesterol transport mechanism to enhance the metabolism of the oxLDL that could prevent both lipid accumulation and foam cell formation and further minimise the possible damage of vessels caused by the oxLDL.

  9. Sesamin Enhances Cholesterol Efflux in RAW264.7 Macrophages

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    Nan Liu; Chongming Wu; Lizhong Sun; Jun Zheng; Peng Guo

    2014-01-01

    Foam cells formation as a result of the uncontrolled cytophagy of modified cholesterol by macrophages plays a key role in the occurrence and development of atherosclerosis. Sesamin is an active constituent of Sesamum indicum which has been shown to possess multiple pharmacological activities. In this work, we investigated the effects of sesamin on foam cell formation and cholesterol efflux in RAW264.7 macrophages. Sesamin dose-dependently inhibited the enhanced cholesterol accumulation elicit...

  10. Activation of GPR55 Receptors Exacerbates oxLDL-Induced Lipid Accumulation and Inflammatory Responses, while Reducing Cholesterol Efflux from Human Macrophages.

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    Mirko Lanuti

    Full Text Available The G protein-coupled receptor GPR55 has been proposed as a new cannabinoid receptor associated with bone remodelling, nervous system excitability, vascular homeostasis as well as in several pathophysiological conditions including obesity and cancer. However, its physiological role and underlying mechanism remain unclear. In the present work, we demonstrate for the first time its presence in human macrophages and its increased expression in ox-LDL-induced foam cells. In addition, pharmacological activation of GPR55 by its selective agonist O-1602 increased CD36- and SRB-I-mediated lipid accumulation and blocked cholesterol efflux by downregulating ATP-binding cassette (ABC transporters ABCA1 and ABCG1, as well as enhanced cytokine- and pro-metalloprotease-9 (pro-MMP-9-induced proinflammatory responses in foam cells. Treatment with cannabidiol, a selective antagonist of GPR55, counteracted these pro-atherogenic and proinflammatory O-1602-mediated effects. Our data suggest that GPR55 could play deleterious role in ox-LDL-induced foam cells and could be a novel pharmacological target to manage atherosclerosis and other related cardiovascular diseases.

  11. Activation of GPR55 Receptors Exacerbates oxLDL-Induced Lipid Accumulation and Inflammatory Responses, while Reducing Cholesterol Efflux from Human Macrophages.

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    Lanuti, Mirko; Talamonti, Emanuela; Maccarrone, Mauro; Chiurchiù, Valerio

    2015-01-01

    The G protein-coupled receptor GPR55 has been proposed as a new cannabinoid receptor associated with bone remodelling, nervous system excitability, vascular homeostasis as well as in several pathophysiological conditions including obesity and cancer. However, its physiological role and underlying mechanism remain unclear. In the present work, we demonstrate for the first time its presence in human macrophages and its increased expression in ox-LDL-induced foam cells. In addition, pharmacological activation of GPR55 by its selective agonist O-1602 increased CD36- and SRB-I-mediated lipid accumulation and blocked cholesterol efflux by downregulating ATP-binding cassette (ABC) transporters ABCA1 and ABCG1, as well as enhanced cytokine- and pro-metalloprotease-9 (pro-MMP-9)-induced proinflammatory responses in foam cells. Treatment with cannabidiol, a selective antagonist of GPR55, counteracted these pro-atherogenic and proinflammatory O-1602-mediated effects. Our data suggest that GPR55 could play deleterious role in ox-LDL-induced foam cells and could be a novel pharmacological target to manage atherosclerosis and other related cardiovascular diseases.

  12. Melanocortin 1 Receptor Signaling Regulates Cholesterol Transport in Macrophages.

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    Rinne, Petteri; Rami, Martina; Nuutinen, Salla; Santovito, Donato; van der Vorst, Emiel P C; Guillamat-Prats, Raquel; Lyytikäinen, Leo-Pekka; Raitoharju, Emma; Oksala, Niku; Ring, Larisa; Cai, Minying; Hruby, Victor J; Lehtimäki, Terho; Weber, Christian; Steffens, Sabine

    2017-07-04

    The melanocortin 1 receptor (MC1-R) is expressed by monocytes and macrophages, where it exerts anti-inflammatory actions on stimulation with its natural ligand α-melanocyte-stimulating hormone. The present study was designed to investigate the specific role of MC1-R in the context of atherosclerosis and possible regulatory pathways of MC1-R beyond anti-inflammation. Human and mouse atherosclerotic samples and primary mouse macrophages were used to study the regulatory functions of MC1-R. The impact of pharmacological MC1-R activation on atherosclerosis was assessed in apolipoprotein E-deficient mice. Characterization of human and mouse atherosclerotic plaques revealed that MC1-R expression localizes in lesional macrophages and is significantly associated with the ATP-binding cassette transporters ABCA1 and ABCG1, which are responsible for initiating reverse cholesterol transport. Using bone marrow-derived macrophages, we observed that α-melanocyte-stimulating hormone and selective MC1-R agonists similarly promoted cholesterol efflux, which is a counterregulatory mechanism against foam cell formation. Mechanistically, MC1-R activation upregulated the levels of ABCA1 and ABCG1. These effects were accompanied by a reduction in cell surface CD36 expression and in cholesterol uptake, further protecting macrophages from excessive lipid accumulation. Conversely, macrophages deficient in functional MC1-R displayed a phenotype with impaired efflux and enhanced uptake of cholesterol. Pharmacological targeting of MC1-R in atherosclerotic apolipoprotein E-deficient mice reduced plasma cholesterol levels and aortic CD36 expression and increased plaque ABCG1 expression and signs of plaque stability. Our findings identify a novel role for MC1-R in macrophage cholesterol transport. Activation of MC1-R confers protection against macrophage foam cell formation through a dual mechanism: It prevents cholesterol uptake while concomitantly promoting ABCA1- and ABCG1-mediated reverse

  13. PENGHAMBATAN OKSIDASI LDL DAN AKUMULASI KOLESTEROL PADA MAKROFAG OLEH EKSTRAK TEMULAWAK (Curcuma xanthorriza Roxb [The Inhibition of Low Density Lipoprotein Oxidation and Cholesterol Accumulation on the Macrophage by Temulawak Extract

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    Aisyah Tri Septiana1

    2006-12-01

    Full Text Available Coronary heart disease is caused among others by atherosclerosis, which is the result of oxidized low density lipoprotein (LDL and cholesterol accumulation on macrophage, and which is inhibited by temulawak (Curcuma xanthorriza Roxb extract. The objective of this study was to find out the kinds and consentration of temulawak extract which could inhibit LDL oxidation, and to find out the effect of temulawak extract on the accumulation of cholesterol on macrophage. Temulawak was extracted by water, ethanol, aceton and dichlorometane. Inhibition of LDL oxidation was found out by measuring the level of malonaldehyde content of oxidized LDL-CuSO4 which was supplemented with water extract, ethanol extract, aceton extract and dichlorometane extract. of temulawak at concentrations of 43 g, 430 g, and 4300 g per ml of LDL. The percentage of malonaldehyde reduction due to supplementation with water extract, ethanol extract, acetone extract and dichloromethane extract was 44.27; 47.68; 51.83 and 61.2 respectively. The inhibition of LDL oxidation by temulawak extract depends on its concentration. The percentage of malonaldehyde reduction due to supplementation with temulawak extract of 43 µg, 430 µg, and 4300 µg per ml of LDL was 43.63; 56.72; and 53.89.. Concentration of temulawak extract resulting in the highest inhibition of LDL oxidation was 430 µg/ml LDL. Temulawak extract tends to inhibit cholesterol accumulation on macrophage. There is a relationship between the inhibition of cholesterol accumulation on the macrophage and the inhibition of LDL oxidation by temulawak extract

  14. Human immunodeficiency virus impairs reverse cholesterol transport from macrophages.

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    Zahedi Mujawar

    2006-10-01

    Full Text Available Several steps of HIV-1 replication critically depend on cholesterol. HIV infection is associated with profound changes in lipid and lipoprotein metabolism and an increased risk of coronary artery disease. Whereas numerous studies have investigated the role of anti-HIV drugs in lipodystrophy and dyslipidemia, the effects of HIV infection on cellular cholesterol metabolism remain uncharacterized. Here, we demonstrate that HIV-1 impairs ATP-binding cassette transporter A1 (ABCA1-dependent cholesterol efflux from human macrophages, a condition previously shown to be highly atherogenic. In HIV-1-infected cells, this effect was mediated by Nef. Transfection of murine macrophages with Nef impaired cholesterol efflux from these cells. At least two mechanisms were found to be responsible for this phenomenon: first, HIV infection and transfection with Nef induced post-transcriptional down-regulation of ABCA1; and second, Nef caused redistribution of ABCA1 to the plasma membrane and inhibited internalization of apolipoprotein A-I. Binding of Nef to ABCA1 was required for down-regulation and redistribution of ABCA1. HIV-infected and Nef-transfected macrophages accumulated substantial amounts of lipids, thus resembling foam cells. The contribution of HIV-infected macrophages to the pathogenesis of atherosclerosis was supported by the presence of HIV-positive foam cells in atherosclerotic plaques of HIV-infected patients. Stimulation of cholesterol efflux from macrophages significantly reduced infectivity of the virions produced by these cells, and this effect correlated with a decreased amount of virion-associated cholesterol, suggesting that impairment of cholesterol efflux is essential to ensure proper cholesterol content in nascent HIV particles. These results reveal a previously unrecognized dysregulation of intracellular lipid metabolism in HIV-infected macrophages and identify Nef and ABCA1 as the key players responsible for this effect. Our findings

  15. Sesamin Enhances Cholesterol Efflux in RAW264.7 Macrophages

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    Nan Liu

    2014-06-01

    Full Text Available Foam cells formation as a result of the uncontrolled cytophagy of modified cholesterol by macrophages plays a key role in the occurrence and development of atherosclerosis. Sesamin is an active constituent of Sesamum indicum which has been shown to possess multiple pharmacological activities. In this work, we investigated the effects of sesamin on foam cell formation and cholesterol efflux in RAW264.7 macrophages. Sesamin dose-dependently inhibited the enhanced cholesterol accumulation elicited by oxidized low-density lipoprotein cholesterol (oxLDL in RAW264.7 cells. Treatment with sesamin (10 μM significantly enhanced cholesterol efflux mediated by high-density lipoprotein (HDL. Realtime quantitative PCR and luciferase assays showed that sesamin significantly increased the mRNA levels of PPARγ, LXRα, and ABCG1, and increased the transcriptional activity of PPARγ. The stimulating effect of sesamin on cholesterol efflux was substantially inhibited by the co-treatment with GW9662, a potent inhibitor of PPARγ. These results suggest that sesamin is a new inhibitor of foam cell formation that may stimulate cholesterol efflux through upregulation of the PPARγ-LXRα-ABCG1 pathway.

  16. Sesamin enhances cholesterol efflux in RAW264.7 macrophages.

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    Liu, Nan; Wu, Chongming; Sun, Lizhong; Zheng, Jun; Guo, Peng

    2014-06-06

    Foam cells formation as a result of the uncontrolled cytophagy of modified cholesterol by macrophages plays a key role in the occurrence and development of atherosclerosis. Sesamin is an active constituent of Sesamum indicum which has been shown to possess multiple pharmacological activities. In this work, we investigated the effects of sesamin on foam cell formation and cholesterol efflux in RAW264.7 macrophages. Sesamin dose-dependently inhibited the enhanced cholesterol accumulation elicited by oxidized low-density lipoprotein cholesterol (oxLDL) in RAW264.7 cells. Treatment with sesamin (10 μM) significantly enhanced cholesterol efflux mediated by high-density lipoprotein (HDL). Realtime quantitative PCR and luciferase assays showed that sesamin significantly increased the mRNA levels of PPARγ, LXRα, and ABCG1, and increased the transcriptional activity of PPARγ. The stimulating effect of sesamin on cholesterol efflux was substantially inhibited by the co-treatment with GW9662, a potent inhibitor of PPARγ. These results suggest that sesamin is a new inhibitor of foam cell formation that may stimulate cholesterol efflux through upregulation of the PPARγ-LXRα-ABCG1 pathway.

  17. Concentration-Dependent Diversifcation Effects of Free Cholesterol Loading on Macrophage Viability and Polarization

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    Xiaoyang Xu

    2015-08-01

    Full Text Available Background/Aims: The accumulation of free cholesterol in atherosclerotic lesions has been well documented in both animals and humans. In studying the relevance of free cholesterol buildup in atherosclerosis, contradictory results have been generated, indicating that free cholesterol produces both pro- and anti-atherosclerosis effects in macrophages. This inconsistency might stem from the examination of only select concentrations of free cholesterol. In the present study, we sought to investigate the implication of excess free cholesterol loading in the pathophysiology of atherosclerosis across a broad concentration range from (in µg/ml 0 to 60. Methods: Macrophage viability was determined by measuring formazan formation and flow cytometry viable cell counting. The polarization of M1 and M2 macrophages was differentiated by FACS (Fluorescence-Activated Cell Sorting assay. The secretion of IL-1β in macrophage culture medium was measured by ELISA kit. Macrophage apoptosis was detected by flow cytometry using a TUNEL kit. Results: Macrophage viability was increased at the treatment of lower concentrations of free cholesterol from (in µg/ml 0 to 20, but gradually decreased at higher concentrations from 20 to 60. Lower free cholesterol loading induced anti-inflammatory M2 macrophage polarization. The activation of the PPARγ (Peroxisome Proliferator-Activated Receptor gamma nuclear factor underscored the stimulation of this M2 phenotype. Nevertheless, higher levels of free cholesterol resulted in pro-inflammatory M1 activation. Moreover, with the application of higher free cholesterol concentrations, macrophage apoptosis and secretion of the inflammatory cytokine IL-1β increased significantly. Conclusion: These results for the first time demonstrate that free cholesterol could render concentration-dependent diversification effects on macrophage viability, polarization, apoptosis and inflammatory cytokine secretions, thereby reconciling the pros

  18. 9-cis β-Carotene Increased Cholesterol Efflux to HDL in Macrophages

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    Sapir Bechor

    2016-07-01

    Full Text Available Cholesterol efflux from macrophages is a key process in reverse cholesterol transport and, therefore, might inhibit atherogenesis. 9-cis-β-carotene (9-cis-βc is a precursor for 9-cis-retinoic-acid (9-cis-RA, which regulates macrophage cholesterol efflux. Our objective was to assess whether 9-cis-βc increases macrophage cholesterol efflux and induces the expression of cholesterol transporters. Enrichment of a mouse diet with βc from the alga Dunaliella led to βc accumulation in peritoneal macrophages. 9-cis-βc increased the mRNA levels of CYP26B1, an enzyme that regulates RA cellular levels, indicating the formation of RA from βc in RAW264.7 macrophages. Furthermore, 9-cis-βc, as well as all-trans-βc, significantly increased cholesterol efflux to high-density lipoprotein (HDL by 50% in RAW264.7 macrophages. Likewise, food fortification with 9-cis-βc augmented cholesterol efflux from macrophages ex vivo. 9-cis-βc increased both the mRNA and protein levels of ABCA1 and apolipoprotein E (APOE and the mRNA level of ABCG1. Our study shows, for the first time, that 9-cis-βc from the diet accumulates in peritoneal macrophages and increases cholesterol efflux to HDL. These effects might be ascribed to transcriptional induction of ABCA1, ABCG1, and APOE. These results highlight the beneficial effect of βc in inhibition of atherosclerosis by improving cholesterol efflux from macrophages.

  19. Transfer of cholesterol from macrophages to lymphocytes in culture.

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    de Bittencourt Júnior, P I; Curi, R

    1998-02-01

    A major feature of macrophage metabolism is its capacity to produce and export cholesterol. Several reports have shown that the manipulation of lymphocyte cholesterol content elicits important changes in lymphocyte proliferation. These findings lead to an inquiry as to whether macrophage-derived cholesterol released into the lymphocyte surroundings may be transferred to the latter thus affecting lymphocyte function. In this study, cholesterol transfer from macrophages to lymphocytes was examined in vitro using rat cells in culture. The findings indicate that there may be a significant transfer of cholesterol from [4-14C]cholesterol labeled resident peritoneal macrophages to mesenteric lymph node resting lymphocytes (up to 173.9 +/- 2.7 pmol/10(7) lymphocytes/10(7) macrophages when co-cultivated for 48 h), in a lipoprotein-dependent manner. This represents the mass transfer of ca. 17 nmoles of cholesterol molecules per 10(7) lymphocytes from 10(7) macrophages (calculated on the basis of specific radioactivity incorporated into macrophages after the pre-labelling period), which suggests that macrophages are capable of replacing the whole lymphocyte cholesterol pool every 21 h. Moreover, an 111%-increase in the total cholesterol content of lymphocytes was found after co-cultivation with macrophages for 48 h. When compared to peritoneal cells, monocytes/macrophages obtained from circulating blood leukocytes presented a much higher cholesterol transfer capacity to lymphocytes (3.06 +/- 0.10 nmol/10(7) lymphocytes/10(7) macrophages co-cultivated for 24 h). Interestingly, inflammatory macrophages dramatically reduced their cholesterol transfer ability (by up to 91%, as compared to resident macrophages). Cholesterol transfer may involve a humoral influence, since it is not only observed when cells are co-cultivated in a single-well chamber system (cells in direct contact), but also in a two-compartment system (where cells can communicate but not by direct contact). Co

  20. Activation of GPR55 Receptors Exacerbates oxLDL-Induced Lipid Accumulation and Inflammatory Responses, while Reducing Cholesterol Efflux from Human Macrophages

    OpenAIRE

    2015-01-01

    The G protein-coupled receptor GPR55 has been proposed as a new cannabinoid receptor associated with bone remodelling, nervous system excitability, vascular homeostasis as well as in several pathophysiological conditions including obesity and cancer. However, its physiological role and underlying mechanism remain unclear. In the present work, we demonstrate for the first time its presence in human macrophages and its increased expression in ox-LDL-induced foam cells. In addition, pharmacologi...

  1. Inhibition of Cholesterol Esterification Influences Cytokine Exspression in Lypopolisaccharide-activated P388D1 Macrophages

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    Rosa Rita Bonatesta

    2007-01-01

    Full Text Available Several in vivo and in vitro studies have demonstrated the involvement of infectious agents in the development of atherosclerosis. However, the mechanisms by which micro-organisms induce and/or aggravate atherosclerosis, are so far unclear. Accumulation of cholesterol esters and lipid laden cell formation are hallmark of the atherogenesis, however, the possible relationship between cholesterol esterification and the signal-transducing component of LPS recognition complex inducing cytokine secretion has not been yet investigated. In the present study, we investigated the effect of mevinolin, the ACAT inhibitor, Sandoz 58035, and plasma from statin-treated hypercholesterolemic patients on cholesterol metabolism and cytokine expression in LPS activated P388D1 macrophages. In P388D1 macrophages cholesterol synthesis and uptake, as well as cholesterol ester synthesis, were unchanged following LPS-activation. When cells were grown in presence of serum from patients under statin therapy, cholesterol esterification was lower compared to cells grown with plasma from healthy subjects, independently from the type of statin used. This effect was accompanied by inhibition of IL-1β expression in LPS activated cells. The ACAT inhibitor, Sandoz 58035, which completely blocked cholesterol esterification in normal and LPS-activated macrophages, prevented IL-1β and IL-6 over-expression in LPS activated cells. Although preliminary, these data point to a possible relationship between cholesterol esterification and cytokine production in macrophages, prospecting new possible mechanisms by which microbial or inflammatory agents may induce and/or accelerate the atherosclerotic process.

  2. Bis(Monoacylglycero)Phosphate, oxysterols and ORP11 : a threesome regulating intracellular cholesterol traffic in macrophages

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    Arnal, Maud

    2015-01-01

    Atherosclerosis is a major cardiovascular complication in increased oxidative stress-related diseases such as type 2 diabetes and metabolic syndrome. In these situations, the low density lipoproteins (LDL) undergo oxidation and their high uptake induces cholesterol accumulation in subendothelial macrophages. On the other hand, oxidized LDL are enriched in cholesterol oxidation products called oxysterols, some of them are involved in the ability of oxidized LDL to induce cellular oxidative str...

  3. Dual Use of Amphiphilic Macromolecules As Cholesterol Efflux Triggers and Inhibitors of Macrophage Athero-inflammation

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    Iverson, Nicole; Plourde, Nicole M.; Sparks, Sarah M.; Wang, Jinzhong; Patel, Ekta; Shah, Pratik; Lewis, Daniel R.; Zablocki, Kyle; Nackman, Gary B.; Uhrich, Kathryn E.; Moghe, Prabhas V.

    2011-01-01

    Activated vascular wall macrophages can rapidly internalize modified lipoproteins and escalate the growth of atherosclerotic plaques. This article proposes a biomaterials-based therapeutic intervention for depletion of non-regulated cholesterol accumulation and inhibition of inflammation of macrophages. Macromolecules with high scavenger receptor (SR)-binding activity were investigated for SR-mediated delivery of agonists to cholesterol-trafficking nuclear liver-X receptors. From a diverse feature space of a family of amphiphilic macromolecules of linear and aromatic mucic acid backbones modified with varied aliphatic chains and conjugated with differentially branched poly(ethylene glycol), a key molecule (carboxyl-terminated, C12-derivatized, linear mucic acid backbone) was selected for its ability to preferentially bind scavenger receptor A (SR-A) as the key target. At a basal level, this macromolecule suppressed the pro-inflammatory signaling of activated THP-1 macrophages while competitively lowering oxLDL uptake in vitro through scavenger receptor SRA-1 targeting. To further deplete intracellular cholesterol, the core macromolecule structure was exploited to solubilize a hydrophobic small molecule agonist for nuclear Liver-X Receptors, which regulate the efflux of intracellular cholesterol. The macromolecule-encapsulated agonist system was found to reduce oxLDL accumulation by 88% in vitro in comparison to controls. In vivo studies were designed to release the macromolecules (with or without encapsulated agonist) to injured carotid arteries within Sprague Dawley rats fed a high fat diet, conditions that yield enhanced cholesterol accumulation and macrophage recruitment. The macromolecules lowered intimal levels of accumulated cholesterol (50% for macromolecule alone; 70% for macromolecule-encapsulated agonist) and inhibited macrophage retention (92% for macromolecule; 96% for macromolecule-encapsulated agonist; 4 days) relative to non-treated controls. Thus

  4. Transintestinal and Biliary Cholesterol Secretion Both Contribute to Macrophage Reverse Cholesterol Transport in Rats

    NARCIS (Netherlands)

    de Boer, Jan Freark; Schonewille, Marleen; Dikkers, Arne; Koehorst, Martijn; Havinga, Rick; Kuipers, Folkert; Tietge, Uwe J F; Groen, Albert K

    2017-01-01

    OBJECTIVE: Reverse cholesterol transport comprises efflux of cholesterol from macrophages and its subsequent removal from the body with the feces and thereby protects against formation of atherosclerotic plaques. Because of lack of suitable animal models that allow for evaluation of the respective c

  5. Minimally oxidized LDL offsets the apoptotic effects of extensively oxidized LDL and free cholesterol in macrophages.

    Science.gov (United States)

    Boullier, Agnès; Li, Yankun; Quehenberger, Oswald; Palinski, Wulf; Tabas, Ira; Witztum, Joseph L; Miller, Yury I

    2006-05-01

    Lipid-loaded macrophage-derived foam cells populate atherosclerotic lesions and produce many pro-inflammatory and plaque-destabilizing factors. An excessive accumulation of extensively oxidized low-density lipoprotein (OxLDL) or free cholesterol (FC), both of which are believed to be major lipid components of macrophages in advanced lesions, rapidly induces apoptosis in macrophages. Indeed, there is evidence of macrophage death in lesions, but how the surviving macrophages avoid death induced by OxLDL, FC, and other factors is not known. Minimally oxidized LDL (mmLDL), which is an early product of progressive LDL oxidation in atherosclerotic lesions, countered OxLDL-induced or FC-induced apoptosis and stimulated macrophage survival both in cell culture and in vivo. DNA fragmentation and caspase-3 activity in OxLDL-treated peritoneal macrophages were significantly reduced by coincubation with mmLDL. In a separate set of experiments, mmLDL significantly reduced annexin V binding to macrophages in which apoptosis was induced by FC loading. In both cellular models, mmLDL activated a pro-survival PI3K/Akt signaling pathway, and PI3K inhibitors, wortmannin and LY294002, eliminated the pro-survival effect of mmLDL. Immunohistochemical examination demonstrated phospho-Akt in murine atherosclerotic lesions. Minimally oxidized LDL, an early form of oxidized LDL in atherosclerotic lesions, may contribute to prolonged survival of macrophage foam cells in lesions via a PI3K/Akt-dependent mechanism.

  6. Differential regulation of gene expression by LXRs in response to macrophage cholesterol loading.

    Science.gov (United States)

    Ignatova, Irena D; Angdisen, Jerry; Moran, Erin; Schulman, Ira G

    2013-07-01

    The ability of cells to precisely control gene expression in response to intracellular and extracellular signals plays an important role in both normal physiology and in pathological settings. For instance, the accumulation of excess cholesterol by macrophages initiates a genetic response mediated by the liver X receptors (LXRs)-α (NR1H3) and LXRβ (NR1H2), which facilitates the transport of cholesterol out of cells to high-density lipoprotein particles. Studies using synthetic LXR agonists have also demonstrated that macrophage LXR activation simultaneously induces a second network of genes that promotes fatty acid and triglyceride synthesis that may support the detoxification of excess free cholesterol by storage in the ester form. We now show that treatment of human THP-1 macrophages with endogenous or synthetic LXR ligands stimulates both transcriptional and posttranscriptional pathways that result in the selective recruitment of the LXRα subtype to LXR-regulated promoters. Interestingly, when human or mouse macrophages are loaded with cholesterol under conditions that mimic the development of atherogenic macrophage foam cells, a selective LXR response is generated that induces genes mediating cholesterol transport but does not coordinately regulate genes involved in fatty acid synthesis. The gene-selective response to cholesterol loading occurs, even in the presence of LXRα binding to the promoter of the gene encoding the sterol regulatory element-binding protein-1c, the master transcriptional regulator of fatty acid synthesis. The ability of promoter bound LXRα to recruit RNA polymerase to the sterol regulatory element-binding protein-1c promoter, however, appears to be ligand selective.

  7. Lysosomal cholesterol accumulation: driver on the road to inflammation during atherosclerosis and non-alcoholic steatohepatitis.

    Science.gov (United States)

    Hendrikx, T; Walenbergh, S M A; Hofker, M H; Shiri-Sverdlov, R

    2014-05-01

    Many studies show an association between the accumulation of cholesterol inside lysosomes and the progression towards inflammatory disease states that are closely related to obesity. While in the past, the knowledge regarding lysosomal cholesterol accumulation was limited to its association with plaque severity during atherosclerosis, recently, a growing body of evidence indicates a causal link between lysosomal cholesterol accumulation and inflammation. These findings make lysosomal cholesterol accumulation an important target for intervention in metabolic diseases that are characterized by the presence of an inflammatory response. In this review, we aim to show the importance of cholesterol trapping inside lysosomes to the development of inflammation by focusing upon cardiovascular disease and non-alcoholic steatohepatitis (NASH) in particular. We summarize current data supporting the hypothesis that lysosomal cholesterol accumulation plays a key role in the development of inflammation during atherosclerosis and NASH. In addition, potential mechanisms by which disturbed lysosomal function can trigger the inflammatory response, the challenges in improving cholesterol trafficking in macrophages and recent successful research directions will be discussed.

  8. Silicon dioxide nanoparticles increase macrophage atherogenicity: Stimulation of cellular cytotoxicity, oxidative stress, and triglycerides accumulation.

    Science.gov (United States)

    Petrick, Lauren; Rosenblat, Mira; Paland, Nicole; Aviram, Michael

    2016-06-01

    Nanoparticle research has focused on their toxicity in general, while increasing evidence points to additional specific adverse effects on atherosclerosis development. Arterial macrophage cholesterol and triglyceride (TG) accumulation and foam cell formation are the hallmark of early atherogenesis, leading to cardiovascular events. To investigate the in vitro atherogenic effects of silicon dioxide (SiO2 ), J774.1 cultured macrophages (murine cell line) were incubated with SiO2 nanoparticle (SP, d = 12 nm, 0-20 µg/mL), followed by cellular cytotoxicity, oxidative stress, TG and cholesterol metabolism analyses. A significant dose-dependent increase in oxidative stress (up to 164%), in cytotoxicity (up to 390% measured by lactate dehydrogenase (LDH) release), and in TG content (up to 63%) was observed in SiO2 exposed macrophages compared with control cells. A smaller increase in macrophage cholesterol mass (up to 22%) was noted. TG accumulation in macrophages was not due to a decrease in TG cell secretion or to an increased TG biosynthesis rate, but was the result of attenuated TG hydrolysis secondary to decreased lipase activity and both adipose triglyceride lipase (ATGL) and hormone-sensitive lipase (HSL) protein expression (by 42 and 25%, respectively). Overall, SPs showed pro-atherogenic effects on macrophages as observed by cytotoxicity, increased oxidative stress and TG accumulation. © 2014 Wiley Periodicals, Inc. Environ Toxicol 31: 713-723, 2016.

  9. Alginic acid cell entrapment: a novel method for measuring in vivo macrophage cholesterol homeostasis

    Science.gov (United States)

    Sontag, Timothy J.; Chellan, Bijoy; Bhanvadia, Clarissa V.; Getz, Godfrey S.; Reardon, Catherine A.

    2015-01-01

    Macrophage conversion to atherosclerotic foam cells is partly due to the balance of uptake and efflux of cholesterol. Cholesterol efflux from cells by HDL and its apoproteins for subsequent hepatic elimination is known as reverse cholesterol transport. Numerous methods have been developed to measure in vivo macrophage cholesterol efflux. Most methods do not allow for macrophage recovery for analysis of changes in cellular cholesterol status. We describe a novel method for measuring cellular cholesterol balance using the in vivo entrapment of macrophages in alginate, which retains incorporated cells while being permeable to lipoproteins. Recipient mice were injected subcutaneously with CaCl2 forming a bubble into which a macrophage/alginate suspension was injected, entrapping the macrophages. Cells were recovered after 24 h. Cellular free and esterified cholesterol mass were determined enzymatically and normalized to cellular protein. Both normal and cholesterol loaded macrophages undergo measureable changes in cell cholesterol when injected into WT and apoA-I-, LDL-receptor-, or apoE-deficient mice. Cellular cholesterol balance is dependent on initial cellular cholesterol status, macrophage cholesterol transporter expression, and apolipoprotein deficiency. Alginate entrapment allows for the in vivo measurement of macrophage cholesterol homeostasis and is a novel platform for investigating the role of genetics and therapeutic interventions in atherogenesis. PMID:25465389

  10. Pectin penta-oligogalacturonide reduces cholesterol accumulation by promoting bile acid biosynthesis and excretion in high-cholesterol-fed mice.

    Science.gov (United States)

    Zhu, Ru-Gang; Sun, Yan-Di; Hou, Yu-Ting; Fan, Jun-Gang; Chen, Gang; Li, Tuo-Ping

    2017-06-25

    Haw pectin penta-oligogalacturonide (HPPS) has important role in improving cholesterol metabolism and promoting the conversion of cholesterol to bile acids (BA) in mice fed high-cholesterol diet (HCD). However, the mechanism is not clear. This study aims to investigate the effects of HPPS on cholesterol accumulation and the regulation of hepatic BA synthesis and transport in HCD-fed mice. Results showed that HPPS significantly decreased plasma and hepatic TC levels but increased plasma high-density lipoprotein cholesterol (HDL-C) and apolipoprotein A-I (apoA-I) levels, compared to HCD. BA analysis showed that HPPS markedly decreased hepatic and small intestine BA levels but increased the gallbladder BA levels, and finally decreased the total BA pool size, compared to HCD. Studies of molecular mechanism revealed that HPPS promoted hepatic ATP-binding cassette transporter A1 (ABCA1), ATP-binding cassette transporter G1 (ABCG1), and scavenger receptor BI (SR-BI) expression but did not affect ATB binding cassette transporter G5/G8 (ABCG5/8) expression. HPPS inactivated hepatic farnesoid X receptor (FXR) and target genes expression, which resulted in significant increase of cholesterol 7α-hydroxylase 1 (CYP7A1) and sterol 12α-hydroxylase (CYP8B1) expression, with up-regulations of 204.2% and 33.5% for mRNA levels, respectively, compared with HCD. In addition, HPPS markedly enhanced bile salt export pump (BSEP) expression but didn't affect the sodium/taurocholate co-transporting polypeptide (NTCP) expression. In conclusion, the study revealed that HPPS reduced cholesterol accumulation by promoting BA synthesis in the liver and excretion in the feces, and might promote macrophage-to-liver reverse cholesterol transport (RCT) but did not liver-to-fecal RCT. Copyright © 2017 Elsevier B.V. All rights reserved.

  11. Degradation of cholesterol crystals in macrophages: the role of phospholipids

    Science.gov (United States)

    Koren, Eugen; Koscec, Mirna; Fugate, Robert D.

    1991-05-01

    Previous studies from this laboratory demonstrated degradation of cholesterol crystals ingested by macrophages in a cell culture system. Those studies also indicated that intracellular phospholipids could play an important role in mobilization of crystalline cholesterol. The purpose of this study was to further explore the role of each of the three major intracellular phospholipid species in degradation of crystals. Fluorescently labeled cholesterol crystals were incubated with phospholipids over a period of 5 days. Morphological changes in crystals were monitored by the use of digital imaging fluorescence microscopy, fluorescence redistribution after photobleaching, confocal microscopy, as well as epifluorescent and phase contrast microscopy. Results clearly demonstrated that all three phospholipids were able to mobilize crystalline cholesterol; however, mechanisms by which they exerted mobilization were different. Sphingomyelin and phosphatidylcholine were found to cause gradual and uniform dissolution of crystals, more or less preserving their original shape. Phosphatidylethanolamine appeared to penetrate into the crystal, causing its fragmentation and solubilization. In the mixture of all three phospholipids representing the composition found in macrophages, both of the described mechanisms were working simultaneously.

  12. Immunolocalization of acyl-coenzyme A:cholesterol O-acyltransferase in macrophages.

    Science.gov (United States)

    Khelef, N; Buton, X; Beatini, N; Wang, H; Meiner, V; Chang, T Y; Farese, R V; Maxfield, F R; Tabas, I

    1998-05-01

    Macrophages in atherosclerotic lesions accumulate large amounts of cholesteryl-fatty acyl esters ("foam cell" formation) through the intracellular esterification of cholesterol by acyl-coenzyme A:cholesterol O-acyltransferase (ACAT). In this study, we sought to determine the subcellular localization of ACAT in macrophages. Using mouse peritoneal macrophages and immunofluorescence microscopy, we found that a major portion of ACAT was in a dense reticular cytoplasmic network and in the nuclear membrane that colocalized with the luminal endoplasmic reticulum marker protein-disulfide isomerase (PDI) and that was in a similar distribution as the membrane-bound endoplasmic reticulum marker ribophorin. Remarkably, another portion of the macrophage ACAT pattern did not overlap with PDI or ribophorin, but was found in as yet unidentified cytoplasmic structures that were juxtaposed to the nucleus. Compartments containing labeled beta-very low density lipoprotein, an atherogenic lipoprotein, did not overlap with the ACAT label, but rather were embedded in the dense reticular network of ACAT. Furthermore, cell-surface biotinylation experiments revealed that freshly harvested, non-attached macrophages, but not those attached to tissue culture dishes, contained approximately 10-15% of ACAT on the cell surface. In summary, ACAT was found in several sites in macrophages: a cytoplasmic reticular/nuclear membrane site that overlaps with PDI and ribophorin and has the characteristics of the endoplasmic reticulum, a perinuclear cytoplasmic site that does not overlap with PDI or ribophorin and may be another cytoplasmic structure or possibly a unique subcompartment of the endoplasmic reticulum, and a cell-surface site in non-attached macrophages. Understanding possible physiological differences of ACAT in these locations may reveal an important component of ACAT regulation and macrophage foam cell formation.

  13. Dietary interesterified fat enriched with palmitic acid induces atherosclerosis by impairing macrophage cholesterol efflux and eliciting inflammation.

    Science.gov (United States)

    Afonso, Milessa Silva; Lavrador, Maria Silvia Ferrari; Koike, Marcia Kiyomi; Cintra, Dennys Esper; Ferreira, Fabiana Dias; Nunes, Valeria Sutti; Castilho, Gabriela; Gioielli, Luiz Antonio; Paula Bombo, Renata; Catanozi, Sergio; Caldini, Elia Garcia; Damaceno-Rodrigues, Nilsa Regina; Passarelli, Marisa; Nakandakare, Edna Regina; Lottenberg, Ana Maria

    2016-06-01

    Interesterified fats are currently being used to replace trans fatty acids. However, their impact on biological pathways involved in the atherosclerosis development was not investigated. Weaning male LDLr-KO mice were fed for 16weeks on a high-fat diet (40% energy as fat) containing polyunsaturated (PUFA), TRANS, palmitic (PALM), palmitic interesterified (PALM INTER), stearic (STEAR) or stearic interesterified (STEAR INTER). Plasma lipids, lipoprotein profile, arterial lesion area, macrophage infiltration, collagen content and inflammatory response modulation were determined. Macrophage cholesterol efflux and the arterial expression of cholesterol uptake and efflux receptors were also performed. The interesterification process did not alter plasma lipid concentrations. Although PALM INTER did not increase plasma cholesterol concentration as much as TRANS, the cholesterol enrichment in the LDL particle was similar in both groups. Moreover, PALM INTER induced the highest IL-1β, MCP-1 and IL-6 secretion from peritoneal macrophages as compared to others. This inflammatory response elicited by PALM INTER was confirmed in arterial wall, as compared to PALM. These deleterious effects of PALM INTER culminate in higher atherosclerotic lesion, macrophage infiltration and collagen content than PALM, STEAR, STEAR INTER and PUFA. These events can partially be attributed to a macrophage cholesterol accumulation, promoted by apoAI and HDL2-mediated cholesterol efflux impairment and increased Olr-1 and decreased Abca1 and Nr1h3 expressions in the arterial wall. Interesterified fats containing palmitic acid induce atherosclerosis development by promoting cholesterol accumulation in LDL particles and macrophagic cells, activating the inflammatory process in LDLr-KO mice.

  14. Role of ACAT1-positive late endosomes in macrophages: cholesterol metabolism and therapeutic applications for Niemann-Pick disease type C.

    Science.gov (United States)

    Sakashita, Naomi; Lei, XiaoFeng; Kamikawa, Masashi; Nishitsuji, Kazuchika

    2014-01-01

    Macrophages in hyperlipidemic conditions accumulate cholesterol esters and develop into foamy transformed macrophages. During this transformation, macrophages demonstrate endoplasmic reticulum fragmentation and consequently produce acyl coenzyme A: cholesterol acyltransferase 1 (ACAT1)-positive late endosomes (ACAT1-LE). ACAT1-LE-positive macrophages effectively esterify modified or native low-density lipoprotein-derived free cholesterol, which results in efficient cholesterol esterification as well as atherosclerotic plaque formation. These macrophages show significant cholesterol ester formation even when free cholesterol egress from late endosomes is impaired, which indicates that free cholesterol is esterified at ACAT1-LE. Genetic blockade of cholesterol egress from late endosomes causes Niemann-Pick disease type C (NPC), an inherited lysosomal storage disease with progressive neurodegeneration. Induction of ACAT1-LE in macrophages with the NPC phenotype led to significant recovery of cholesterol esterification. In addition, in vivo ACAT1-LE induction significantly extended the lifespan of mice with the NPC phenotype. Thus, ACAT1-LE not only regulates intracellular cholesterol metabolism but also ameliorates NPC pathophysiology.

  15. Transintestinal and Biliary Cholesterol Secretion Both Contribute to Macrophage Reverse Cholesterol Transport in Rats-Brief Report.

    Science.gov (United States)

    de Boer, Jan Freark; Schonewille, Marleen; Dikkers, Arne; Koehorst, Martijn; Havinga, Rick; Kuipers, Folkert; Tietge, Uwe J F; Groen, Albert K

    2017-04-01

    Reverse cholesterol transport comprises efflux of cholesterol from macrophages and its subsequent removal from the body with the feces and thereby protects against formation of atherosclerotic plaques. Because of lack of suitable animal models that allow for evaluation of the respective contributions of biliary cholesterol secretion and transintestinal cholesterol excretion (TICE) to macrophage reverse cholesterol transport under physiological conditions, the relative importance of both pathways in this process has remained controversial. To separate cholesterol traffic via the biliary route from TICE, bile flow was mutually diverted between rats, continuously, for 3 days. Groups of 2 weight-matched rats were designated as a pair, and both rats were equipped with cannulas in the bile duct and duodenum. Bile from rat 1 was diverted to the duodenum of rat 2, whereas bile from rat 2 was rerouted to the duodenum of rat 1. Next, rat 1 was injected with [(3)H]cholesterol-loaded macrophages. [(3)H]Cholesterol secreted via the biliary route was consequently diverted to rat 2 and could thus be quantified from the feces of that rat. On the other hand, [(3)H]cholesterol tracer in the feces of rat 1 reflected macrophage-derived cholesterol excreted via TICE. Using this setup, we found that 63% of the label secreted with the fecal neutral sterols had travelled via the biliary route, whereas 37% was excreted via TICE. TICE and biliary cholesterol secretion contribute to macrophage reverse cholesterol transport in rats. The majority of macrophage-derived cholesterol is however excreted via the hepatobiliary route. © 2017 American Heart Association, Inc.

  16. Polyoxygenated Cholesterol Ester Hydroperoxide Activates TLR4 and SYK Dependent Signaling in Macrophages

    Science.gov (United States)

    Choi, Soo-Ho; Yin, Huiyong; Ravandi, Amir; Armando, Aaron; Dumlao, Darren; Kim, Jungsu; Almazan, Felicidad; Taylor, Angela M.; McNamara, Coleen A.; Tsimikas, Sotirios; Dennis, Edward A.; Witztum, Joseph L.; Miller, Yury I.

    2013-01-01

    Oxidation of low-density lipoprotein (LDL) is one of the major causative mechanisms in the development of atherosclerosis. In previous studies, we showed that minimally oxidized LDL (mmLDL) induced inflammatory responses in macrophages, macropinocytosis and intracellular lipid accumulation and that oxidized cholesterol esters (OxCEs) were biologically active components of mmLDL. Here we identified a specific OxCE molecule responsible for the biological activity of mmLDL and characterized signaling pathways in macrophages in response to this OxCE. Using liquid chromatography – tandem mass spectrometry and biological assays, we identified an oxidized cholesteryl arachidonate with bicyclic endoperoxide and hydroperoxide groups (BEP-CE) as a specific OxCE that activates macrophages in a TLR4/MD-2-dependent manner. BEP-CE induced TLR4/MD-2 binding and TLR4 dimerization, phosphorylation of SYK, ERK1/2, JNK and c-Jun, cell spreading and uptake of dextran and native LDL by macrophages. The enhanced macropinocytosis resulted in intracellular lipid accumulation and macrophage foam cell formation. Bone marrow-derived macrophages isolated from TLR4 and SYK knockout mice did not respond to BEP-CE. The presence of BEP-CE was demonstrated in human plasma and in the human plaque material captured in distal protection devices during percutaneous intervention. Our results suggest that BEP-CE is an endogenous ligand that activates the TLR4/SYK signaling pathway. Because BEP-CE is present in human plasma and human atherosclerotic lesions, BEP-CE-induced and TLR4/SYK-mediated macrophage responses may contribute to chronic inflammation in human atherosclerosis. PMID:24376657

  17. Polyoxygenated cholesterol ester hydroperoxide activates TLR4 and SYK dependent signaling in macrophages.

    Directory of Open Access Journals (Sweden)

    Soo-Ho Choi

    Full Text Available Oxidation of low-density lipoprotein (LDL is one of the major causative mechanisms in the development of atherosclerosis. In previous studies, we showed that minimally oxidized LDL (mmLDL induced inflammatory responses in macrophages, macropinocytosis and intracellular lipid accumulation and that oxidized cholesterol esters (OxCEs were biologically active components of mmLDL. Here we identified a specific OxCE molecule responsible for the biological activity of mmLDL and characterized signaling pathways in macrophages in response to this OxCE. Using liquid chromatography - tandem mass spectrometry and biological assays, we identified an oxidized cholesteryl arachidonate with bicyclic endoperoxide and hydroperoxide groups (BEP-CE as a specific OxCE that activates macrophages in a TLR4/MD-2-dependent manner. BEP-CE induced TLR4/MD-2 binding and TLR4 dimerization, phosphorylation of SYK, ERK1/2, JNK and c-Jun, cell spreading and uptake of dextran and native LDL by macrophages. The enhanced macropinocytosis resulted in intracellular lipid accumulation and macrophage foam cell formation. Bone marrow-derived macrophages isolated from TLR4 and SYK knockout mice did not respond to BEP-CE. The presence of BEP-CE was demonstrated in human plasma and in the human plaque material captured in distal protection devices during percutaneous intervention. Our results suggest that BEP-CE is an endogenous ligand that activates the TLR4/SYK signaling pathway. Because BEP-CE is present in human plasma and human atherosclerotic lesions, BEP-CE-induced and TLR4/SYK-mediated macrophage responses may contribute to chronic inflammation in human atherosclerosis.

  18. Quercetin increases macrophage cholesterol efflux to inhibit foam cell formation through activating PPARγ-ABCA1 pathway

    Science.gov (United States)

    Sun, Liqiang; Li, En; Wang, Feng; Wang, Tao; Qin, Zhiping; Niu, Shaohui; Qiu, Chunguang

    2015-01-01

    The accumulation of cholesterol in macrophages could induce the formation of foam cells and increase the risk of developing atherosclerosis. We wonder if quercetin, one of flavonoids with anti-inflammation functions in different cell types, could elevate the development of foam cells formation in atherosclerosis. We treated foam cells derived from oxLDL induced THP-1 cells with quercetin, and evaluated the foam cells formation, cholesterol content and apoptosis of the cells. We found that quercetin induced the expression of ABCA1 in differentiated THP-1 cells, and increased the cholesterol efflux from THP-1 cell derived foam cells. Eventually, cholesterol level and the formation of foam cell derived from THP-1 cells decreased after quercetin treatment. In addition, quercetin activated PPARγ-LXRα pathway to upregulate ABCA1 expression through increasing protein level of PPARγ and its transcriptional activity. Inhibition of PPARγ activity by siRNA knockdown or the addition of chemical inhibitor, GW9662, abolished quercetin induced ABCA1 expression and cholesterol efflux in THP-1 derived macrophages. Our data demonstrated that quercetin increased cholesterol efflux from macrophages through upregulating the expressions of PPARγ and ABCA1. Taken together, increasing uptake of quercetin or quercetin-rich foods would be an effective way to lower the risk of atherosclerosis. PMID:26617799

  19. Transintestinal and Biliary Cholesterol Secretion Both Contribute to Macrophage Reverse Cholesterol Transport in RatsBrief Report

    NARCIS (Netherlands)

    Boer, de Jan Freark; Schonewille, Marleen; Dikkers, Arne; Koehorst, Martijn; Havinga, Rick; Kuipers, Folkert; Tietge, Uwe J F; Groen, Albert K

    Objective-Reverse cholesterol transport comprises efflux of cholesterol from macrophages and its subsequent removal from the body with the feces and thereby protects against formation of atherosclerotic plaques. Because of lack of suitable animal models that allow for evaluation of the respective

  20. Mycolates of Mycobacterium tuberculosis modulate the flow of cholesterol for bacillary proliferation in murine macrophages.

    Science.gov (United States)

    Vermeulen, Ilke; Baird, Mark; Al-Dulayymi, Juma; Smet, Muriel; Verschoor, Jan; Grooten, Johan

    2017-04-01

    The differentiation of macrophages into lipid-filled foam cells is a hallmark of the lung granuloma that forms in patients with active tuberculosis (TB). Mycolic acids (MAs), the abundant lipid virulence factors in the cell wall of Mycobacterium tuberculosis (Mtb), can induce this foam phenotype possibly as a way to perturb host cell lipid homeostasis to support the infection. It is not exactly clear how MAs allow differentiation of foam cells during Mtb infection. Here we investigated how chemically synthetic MAs, each with a defined stereochemistry similar to natural Mtb-associated mycolates, influence cell foamy phenotype and mycobacterial proliferation in murine host macrophages. Using light and laser-scanning-confocal microscopy, we assessed the influence of MA structure first on the induction of granuloma cell types, second on intracellular cholesterol accumulation, and finally on mycobacterial growth. While methoxy-MAs (mMAs) effected multi-vacuolar giant cell formation, keto-MAs (kMAs) induced abundant intracellular lipid droplets that were packed with esterified cholesterol. Macrophages from mice treated with kMA were permissive to mycobacterial growth, whereas cells from mMA treatment were not. This suggests a separate yet key involvement of oxygenated MAs in manipulating host cell lipid homeostasis to establish the state of TB. Copyright © 2017 by the American Society for Biochemistry and Molecular Biology, Inc.

  1. Effect of high glucose on the expression of CD36 and lipid accumulation in THP-1 macrophages

    Institute of Scientific and Technical Information of China (English)

    谭玉林

    2014-01-01

    Objective To investigate the effect of high glucose on regulating the expression of CD36 and lipid accumulation in THP-1 macrophages.Methods THP-1 macrophages were incubated with different concentrations of D-glucose(5.6,11,20,30 and 35 mmol/L),50 mg/L oxidized low density lipoprotein(ox-LDL),50 mg/L oxLDL+20 mmol/L D-glucose for 24 h.Total cholesterol content in THP-1 macrophages was determined by high performance liquid chromatography,the lipid accumulation was detected by oil red O stain.CD36 mRNA and

  2. Cholesterol crystals activate the NLRP3 inflammasome in human macrophages: a novel link between cholesterol metabolism and inflammation.

    Directory of Open Access Journals (Sweden)

    Kristiina Rajamäki

    Full Text Available BACKGROUND: Chronic inflammation of the arterial wall is a key element in the pathogenesis of atherosclerosis, yet the factors that trigger and sustain the inflammation remain elusive. Inflammasomes are cytoplasmic caspase-1-activating protein complexes that promote maturation and secretion of the proinflammatory cytokines interleukin(IL-1beta and IL-18. The most intensively studied inflammasome, NLRP3 inflammasome, is activated by diverse substances, including crystalline and particulate materials. As cholesterol crystals are abundant in atherosclerotic lesions, and IL-1beta has been linked to atherogenesis, we explored the possibility that cholesterol crystals promote inflammation by activating the inflammasome pathway. PRINCIPAL FINDINGS: Here we show that human macrophages avidly phagocytose cholesterol crystals and store the ingested cholesterol as cholesteryl esters. Importantly, cholesterol crystals induced dose-dependent secretion of mature IL-1beta from human monocytes and macrophages. The cholesterol crystal-induced secretion of IL-1beta was caspase-1-dependent, suggesting the involvement of an inflammasome-mediated pathway. Silencing of the NLRP3 receptor, the crucial component in NLRP3 inflammasome, completely abolished crystal-induced IL-1beta secretion, thus identifying NLRP3 inflammasome as the cholesterol crystal-responsive element in macrophages. The crystals were shown to induce leakage of the lysosomal protease cathepsin B into the cytoplasm and inhibition of this enzyme reduced cholesterol crystal-induced IL-1beta secretion, suggesting that NLRP3 inflammasome activation occurred via lysosomal destabilization. CONCLUSIONS: The cholesterol crystal-induced inflammasome activation in macrophages may represent an important link between cholesterol metabolism and inflammation in atherosclerotic lesions.

  3. Macrophage cholesterol homeostasis and metabolic diseases: critical role of cholesteryl ester mobilization.

    Science.gov (United States)

    Ghosh, Shobha

    2011-03-01

    Atherogenic dyslipidemia, including low HDL levels, is the major contributor of residual risk of cardiovascular disease that remains even after aggressive statin therapy to reduce LDL-cholesterol. Currently, distinction is not made between HDL-cholesterol and HDL, which is a lipoprotein consisting of several proteins and a core containing cholesteryl esters (CEs). The importance of assessing HDL functionality, specifically its role in facilitating cholesterol efflux from foam cells, is relevant to atherogenesis. Since HDLs can only remove unesterified cholesterol from macrophages while cholesterol is stored as CEs within foam cells, intracellular CE hydrolysis by CE hydrolase is vital. Reduction in macrophage lipid burden not only attenuates atherosclerosis but also reduces inflammation and linked pathologies such as Type 2 diabetes and chronic kidney disease. Targeting reduction in macrophage CE levels and focusing on enhancing cholesterol flux from peripheral tissues to liver for final elimination is proposed.

  4. Increased Proinflammatory Cytokine Production and Decreased Cholesterol Efflux Due to Downregulation of ABCG1 in Macrophages Exposed to Indoxyl Sulfate

    Directory of Open Access Journals (Sweden)

    Koji Matsuo

    2015-08-01

    Full Text Available One of the possible causes of enhanced atherosclerosis in patients with chronic kidney disease (CKD is the accumulation of uremic toxins. Since macrophage foam cell formation is a hallmark of atherosclerosis, we examined the direct effect of indoxyl sulfate (IS, a representative uremic toxin, on macrophage function. Macrophages differentiated from THP-1 cells were exposed to IS in vitro. IS decreased the cell viability of THP-1 derived macrophages but promoted the production of inflammatory cytokines (IL-1β, IS 1.0 mM: 101.8 ± 21.8 pg/mL vs. 0 mM: 7.0 ± 0.3 pg/mL, TNF-α, IS 1.0 mM: 96.6 ± 11.0 pg/mL vs. 0 mM: 15.1 ± 3.1 pg/mL and reactive oxygen species. IS reduced macrophage cholesterol efflux (IS 0.5 mM: 30.3% ± 7.3% vs. 0 mM: 43.5% ± 1.6% and decreased ATP-binding cassette transporter G1 expression. However, lipid uptake into cells was not enhanced. A liver X receptor (LXR agonist, T0901317, improved IS-induced production of inflammatory cytokines as well as reduced cholesterol efflux. In conclusion, IS induced inflammatory reactions and reduced cholesterol efflux in macrophages. Both effects of IS were improved with activation of LXR. Direct interactions of uremic toxins with macrophages may be a major cause of atherosclerosis acceleration in patients with CKD.

  5. Macrophage specific caspase-1/11 deficiency protects against cholesterol crystallization and hepatic inflammation in hyperlipidemic mice.

    Directory of Open Access Journals (Sweden)

    Tim Hendrikx

    Full Text Available While non-alcoholic steatohepatitis (NASH is characterized by hepatic steatosis combined with inflammation, the mechanisms triggering hepatic inflammation are unknown. In Ldlr(-/- mice, we have previously shown that lysosomal cholesterol accumulation in Kupffer cells (KCs correlates with hepatic inflammation and cholesterol crystallization. Previously, cholesterol crystals have been shown to induce the activation of inflammasomes. Inflammasomes are protein complexes that induce the processing and release of pro-inflammatory cytokines IL-1b and IL-18 via caspase-1 activation. Whereas caspase-1 activation is independent of caspase-11 in the canonical pathway of inflammasome activation, caspase-11 was found to trigger caspase-1-dependent IL-1b and IL-18 in response to non-canonical inflammasome activators. So far, it has not been investigated whether inflammasome activation stimulates the formation of cholesterol crystals. We hypothesized that inflammasome activation in KCs stimulates cholesterol crystallization, thereby leading to hepatic inflammation.Ldlr (-/- mice were transplanted (tp with wild-type (Wt or caspase-1/11(-/- (dKO bone marrow and fed either regular chow or a high-fat, high-cholesterol (HFC diet for 12 weeks. In vitro, bone marrow derived macrophages (BMDM from wt or caspase-1/11(-/- mice were incubated with oxLDL for 24h and autophagy was assessed.In line with our hypothesis, caspase-1/11(-/--tp mice had less severe hepatic inflammation than Wt-tp animals, as evident from liver histology and gene expression analysis in isolated KCs. Mechanistically, KCs from caspase-1/11(-/--tp mice showed less cholesterol crystals, enhanced cholesterol efflux and increased autophagy. In wt BMDM, oxLDL incubation led to disturbed autophagy activity whereas BMDM from caspase-1/11(-/- mice had normal autophagy activity.Altogether, these data suggest a vicious cycle whereby disturbed autophagy and decreased cholesterol efflux leads to newly formed

  6. Advanced Glycation in macrophages induces intracellular accumulation of 7-ketocholesterol and total sterols by decreasing the expression of ABCA-1 and ABCG-1

    Science.gov (United States)

    2011-01-01

    Background Advanced glycation end products (AGE) alter lipid metabolism and reduce the macrophage expression of ABCA-1 and ABCG-1 which impairs the reverse cholesterol transport, a system that drives cholesterol from arterial wall macrophages to the liver, allowing its excretion into the bile and feces. Oxysterols favors lipid homeostasis in macrophages and drive the reverse cholesterol transport, although the accumulation of 7-ketocholesterol, 7alpha- hydroxycholesterol and 7beta- hydroxycholesterol is related to atherogenesis and cell death. We evaluated the effect of glycolaldehyde treatment (GAD; oxoaldehyde that induces a fast formation of intracellular AGE) in macrophages overloaded with oxidized LDL and incubated with HDL alone or HDL plus LXR agonist (T0901317) in: 1) the intracellular content of oxysterols and total sterols and 2) the contents of ABCA-1 and ABCG-1. Methods Total cholesterol and oxysterol subspecies were determined by gas chromatography/mass spectrometry and HDL receptors content by immunoblot. Results In control macrophages (C), incubation with HDL or HDL + T0901317 reduced the intracellular content of total sterols (total cholesterol + oxysterols), cholesterol and 7-ketocholesterol, which was not observed in GAD macrophages. In all experimental conditions no changes were found in the intracellular content of other oxysterol subspecies comparing C and GAD macrophages. GAD macrophages presented a 45% reduction in ABCA-1 protein level as compared to C cells, even after the addition of HDL or HDL + T0901317. The content of ABCG-1 was 36.6% reduced in GAD macrophages in the presence of HDL as compared to C macrophages. Conclusion In macrophages overloaded with oxidized LDL, glycolaldehyde treatment reduces the HDL-mediated cholesterol and 7-ketocholesterol efflux which is ascribed to the reduction in ABCA-1 and ABCG-1 protein level. This may contribute to atherosclerosis in diabetes mellitus. PMID:21957962

  7. Cholesterol enrichment of human monocyte/macrophages induces surface exposure of phosphatidylserine and the release of biologically-active tissue factor-positive microvesicles.

    Science.gov (United States)

    Liu, Ming-Lin; Reilly, Michael P; Casasanto, Peter; McKenzie, Steven E; Williams, Kevin Jon

    2007-02-01

    Biologically significant amounts of two procoagulant molecules, phosphatidylserine (PS) and tissue factor (TF), are transported by monocyte/macrophage-derived microvesicles (MVs). Because cellular cholesterol accumulation is an important feature of atherosclerotic vascular disease, we now examined effects of cholesterol enrichment on MV release from human monocytes and macrophages. Cholesterol enrichment of human THP-1 monocytes, alone or in combination with lipopolysaccharide (LPS), tripled their total MV generation, as quantified by flow cytometry based on particle size and PS exposure. The subset of these MVs that were also TF-positive was likewise increased by cellular cholesterol enrichment, and these TF-positive MVs exhibited a striking 10-fold increase in procoagulant activity. Moreover, cholesterol enrichment of primary human monocyte-derived macrophages also increased their total as well as TF-positive MV release, and these TF-positive MVs exhibited a similar 10-fold increase in procoagulant activity. To explore the mechanisms of enhanced MV release, we found that cholesterol enrichment of monocytes caused PS exposure on the cell surface by as early as 2 hours and genomic DNA fragmentation in a minority of cells by 20 hours. Addition of a caspase inhibitor at the beginning of these incubations blunted both cholesterol-induced apoptosis and MV release. Cholesterol enrichment of human monocyte/macrophages induces the generation of highly biologically active, PS-positive MVs, at least in part through induction of apoptosis. Cholesterol-induced monocyte/macrophage MVs, both TF-positive and TF-negative, may be novel contributors to atherothrombosis.

  8. Free cholesterol-induced cytotoxicity a possible contributing factor to macrophage foam cell necrosis in advanced atherosclerotic lesions.

    Science.gov (United States)

    Tabas, I

    1997-10-01

    A major characteristic of advanced atherosclerotic lesions is the necrotic, or lipid, core, which likely plays an important role in the clinical progression of these lesions. Recent data suggest that the necrotic core forms primarily as a consequence of macrophage foam cell necrosis. Lesional macrophages initially accumulate mostly cholesteryl esters, but macrophages in advanced lesions contain large amounts of unesterified, or free, cholesterol (FC). Although there are many theories as to why macrophage foam cells die in advanced lesions, the fact that a high FC:phospholipid (PL) ratio in cellular membranes can be toxic to cells suggests that FC-induced cytotoxicity may contribute to foam cell necrosis. The mechanism of FC cytotoxicity can be explained by disturbances in membrane protein function as a result of "stiffening" of the bilayer and by formation of intracellular FC crystals that can cause physical damage to cellular organelles. Macrophages appear to respond to FC loading by a fascinating adaptive response, namely the induction of PL biosynthesis, which initially keeps the cellular FC:PL ratio below toxic levels. Studies with cultured macrophages have demonstrated that a failure of this adaptive response leads to FC-induced foam cell cytotoxicity and necrosis, and thus a similar series of events in advanced atherosclerotic lesions could provide an explanation for the development of the necrotic core. (Trends Cardiovasc Med 1997;7: 256-263). © 1997, Elsevier Science Inc.

  9. Curcumin retunes cholesterol transport homeostasis and inflammation response in M1 macrophage to prevent atherosclerosis.

    Science.gov (United States)

    Chen, Fang-Yuan; Zhou, Juan; Guo, Ning; Ma, Wang-Ge; Huang, Xin; Wang, Huan; Yuan, Zu-Yi

    2015-11-27

    Lipoprotein cholesterol metabolism dysfunction in the arterial wall is a major contributor to atherosclerosis, and excessive lipid intake and failed cholesterol homeostasis may accelerate the atherogenic process. Curcumin exerts multiple effects by alleviating inflammation, hyperlipidemia, and atherosclerosis; however, its role in cholesterol transport homeostasis and its underlying impact on inflammatory M1 macrophages are poorly understood. This work aimed to investigate the effect of curcumin on cholesterol transport, the inflammatory response and cell apoptosis in M1 macrophages. RAW264.7 macrophages (M0) were induced with LPS plus IFN-γ for 12 h to develop a M1 subtype and were then incubated with curcumin at different concentrations (6.25 and 12.5 μmol/L) in the presence or absence of oxLDL. Then, cholesterol influx/efflux and foam cell formation as well as inflammation and apoptosis were evaluated. It was found that curcumin increased cholesterol uptake measured by the Dil-oxLDL binding assay, and simultaneously increased cholesterol efflux carried out by Apo-A1 and HDL in M1 cells. Curcumin further reinforced ox-LDL-induced cholesterol esterification and foam cell formation as determined by Oil Red O and BODIPY staining. Moreover, curcumin dramatically reduced ox-LDL-induced cytokine production such as IL-1β, IL-6 as well as TNF-α and M1 cell apoptosis. We also found that curcumin upregulated CD36 and ABCA1 in M1 macrophages. Curcumin increased PPARγ expression, which in turn promoted CD36 and ABCA1 expression. In conclusion, curcumin may increase the ability of M1 macrophages to handle harmful lipids, thus promoting lipid processing, disposal and removal, which may support cholesterol homeostasis and exert an anti-atherosclerotic effect.

  10. Quercetin improves macrophage reverse cholesterol transport in apolipoprotein E-deficient mice fed a high-fat diet.

    Science.gov (United States)

    Cui, Yingjie; Hou, Pengbo; Li, Fahui; Liu, Qinghua; Qin, Shucun; Zhou, Guanghai; Xu, Xuelian; Si, Yanhong; Guo, Shoudong

    2017-01-14

    Quercetin, one of the most widely distributed flavonoids in plants, has been demonstrated to reduce hyperlipidaemia and atherosclerotic lesion formation. Reverse cholesterol transport (RCT) plays a crucial role in exporting cholesterol from peripheral cells, which is one mechanism utilized in the prevention and treatment of atherosclerosis. The aim of this study is to investigate whether quercetin reduces lipid accumulation by improving RCT in vivo. Apolipoprotein E-deficient mice fed a high-fat diet were used to investigate the effect of quercetin on RCT by an isotope tracing method, and the underlying mechanisms were clarified by molecular techniques. These novel results demonstrated that quercetin significantly improved [(3)H]-cholesterol transfer from [(3)H]-cholesterol-loaded macrophages to the plasma (approximately 34% increase), liver (30% increase), and bile (50% increase) and finally to the feces (approximately 40% increase) for excretion in apolipoprotein E-deficient mice fed a high-fat diet. Furthermore, quercetin markedly increased the cholesterol accepting ability of plasma and high-density lipoprotein (HDL) and dramatically decreased the content of malondialdehyde in plasma and oxidized phosphocholine carried by HDL. Therefore, the underlying mechanisms of quercetin in improving RCT may be partially due to the elevated cholesterol accepting ability of HDL, the increased expression levels of proteins related to RCT, such as ATP-binding cassettes (ABC) A1 and G1, and the improved antioxidant activity of HDL. Quercetin accelerates RCT in an atherosclerosis model, which is helpful in clarifying the lipid-lowering effect of quercetin.

  11. Omega 3 fatty acids promote macrophage reverse cholesterol transport in hamster fed high fat diet.

    Directory of Open Access Journals (Sweden)

    Fatima Kasbi Chadli

    Full Text Available The aim of this study was to investigate macrophage reverse cholesterol transport (RCT in hamster, a CETP-expressing species, fed omega 3 fatty acids (ω3PUFA supplemented high fat diet (HFD. Three groups of hamsters (n = 6/group were studied for 20 weeks: 1 control diet: Control, 2 HFD group: HF and 3 HFD group supplemented with ω3PUFA (EPA and DHA: HFω3. In vivo macrophage-to-feces RCT was assessed after an intraperitoneal injection of (3H-cholesterol-labelled hamster primary macrophages. Compared to Control, HF presented significant (p<0.05 increase in body weight, plasma TG (p<0.01 and cholesterol (p<0.001 with an increase in VLDL TG and in VLDL and LDL cholesterol (p<0.001. Compared to HF, HFω3 presented significant decrease in body weight. HFω3 showed less plasma TG (p<0.001 and cholesterol (p<0.001 related to a decrease in VLDL TG and HDL cholesterol respectively and higher LCAT activity (p<0.05 compared to HF. HFω3 showed a higher fecal bile acid excretion (p<0.05 compared to Control and HF groups and higher fecal cholesterol excretion (p<0.05 compared to HF. This increase was related to higher gene expression of ABCG5, ABCA1 and SR-B1 in HFω3 compared to Control and HF groups (<0.05 and in ABCG1 and CYP7A1 compared to HF group (p<0.05. A higher plasma efflux capacity was also measured in HFω3 using (3H- cholesterol labeled Fu5AH cells. In conclusion, EPA and DHA supplementation improved macrophage to feces reverse cholesterol transport in hamster fed HFD. This change was related to the higher cholesterol and fecal bile acids excretion and to the activation of major genes involved in RCT.

  12. Macrophage cholesterol efflux correlates with lipoprotein subclass distribution and risk of obstructive coronary artery disease in patients undergoing coronary angiography

    Directory of Open Access Journals (Sweden)

    Kremer Werner

    2009-04-01

    Full Text Available Abstract Background Studies in patients with low HDL have suggested that impaired cellular cholesterol efflux is a heritable phenotype increasing atherosclerosis risk. Less is known about the association of macrophage cholesterol efflux with lipid profiles and CAD risk in normolipidemic subjects. We have therefore measured macrophage cholesterol efflux in142 normolipidemic subjects undergoing coronary angiography. Methods Monocytes isolated from blood samples of patients scheduled for cardiac catheterization were differentiated into macrophages over seven days. Isotopic cholesterol efflux to exogenously added apolipoprotein A-I and HDL2 was measured. Quantitative cholesterol efflux from macrophages was correlated with lipoprotein subclass distribution in plasma from the same individuals measured by NMR-spectroscopy of lipids and with the extent of coronary artery disease seen on coronary angiography. Results Macrophage cholesterol efflux was positively correlated with particle concentration of smaller HDL and LDL particles but not with total plasma concentrations of HDL or LDL-cholesterol. We observed an inverse relationship between macrophage cholesterol efflux and the concntration of larger and triglyceride rich particles (VLDL, chylomicrons. Subjects with significant stenosis on coronary angiography had lower cholesterol efflux from macrophages compared to individuals without significant stenosis (adjusted p = 0.02. Conclusion Macrophage cholesterol efflux is inversely correlated with lipoprotein particle size and risk of CAD.

  13. β3-Adrenoceptor activation upregulates apolipoprotein A-I expression in HepG2 cells, which might further promote cholesterol efflux from macrophage foam cells.

    Science.gov (United States)

    Gao, Xia-Qing; Li, Yan-Fang; Jiang, Zhi-Li

    2017-01-01

    The aim of this study was to explore the effects of β3-adrenoceptor (β3-AR) activation on HepG2 cells and its influence on cholesterol efflux from macrophage foam cells. HepG2 cells were cultured and treated with the β3-AR agonist, BRL37344, and antagonist, SR52390A, and the expression of apolipoprotein (Apo) A-I, ApoA-II, ApoB, and β3-AR in the supernatants and cells was determined. The expression of peroxisome proliferator-activated receptor (PPAR) γ and PPARα in the HepG2 cells was also assessed. Next, using the RAW264.7 macrophage foam cell model, we also assessed the influence of the HepG2 cell supernatants on lipid efflux. The cholesterol content of the foam cells was also measured, and the cholesterol efflux from the macrophages was examined by determining (3)H-labeled cholesterol levels. Expression of ATP-binding cassette transporter (ABC) A1 and ABCG1 of the macrophage foam cells was also assessed. β3-AR activation increased ApoA-I expression in both the HepG2 cells and the supernatants; PPARγ expression was upregulated, but PPARα expression was not. Treatment with GW9662 abolished the increased expression of ApoA-I induced by the β3-AR agonist. The HepG2 cell supernatants decreased the lipid accumulation and increased the cholesterol efflux from the macrophage foam cells. ABCA1 expression, but not ABCG1 expression, increased in the macrophage foam cells treated with BRL37344-treated HepG2 cell supernatants. Activation of β3-AR in HepG2 cells upregulates ApoA-I expression, which might further promote cholesterol efflux from macrophage foam cells. PPARγ might be required for the induction of ApoA-I expression.

  14. Induction of DKK1 by ox-LDL negatively regulates intracellular lipid accumulation in macrophages.

    Science.gov (United States)

    Zhang, Yu; Ge, Cheng; Wang, Lin; Liu, Xinxin; Chen, Yifei; Li, Mengmeng; Zhang, Mei

    2015-01-01

    Dickkopf1 (DKK1), a canonical Wnt/β-catenin pathway antagonist, is closely associated with cardiovascular disease and adipogenesis. We performed an in vitro study to determine whether oxidized low-density lipoprotein (ox-LDL) increased the expression of DKK1 in macrophages and whether β-catenin and liver X receptor α (LXRα) were involved in this regulation. Induction of DKK1 expression by ox-LDL decreased the level of lectin-like oxidized low-density lipoprotein receptor-1 (LOX-1) via a Wnt/β-catenin pathway and increased ATP-binding cassette transporter A/G1 (ABCA/G1) levels via a signal transducer and activator of transcription 3 (STAT3) pathway. Lower LOX-1 and higher ABCA/G1 levels inhibited cholesterol loading in macrophages. In conclusion, ox-LDL may induce DKK1 expression in macrophages to inhibit the accumulation of lipids through a mechanism that involves downregulation of LOX-1-mediated lipid uptake and upregulation of ABCA/G1-dependent cholesterol efflux.

  15. A dual enzymatic-biosensor for simultaneous determination of glucose and cholesterol in serum and peritoneal macrophages of diabetic mice: Evaluation of the diabetes-accelerated atherosclerosis risk

    Energy Technology Data Exchange (ETDEWEB)

    Huang Qilin; An Yarui; Tang Linlin; Jiang Xiaoli; Chen Hua; Bi Wenji [Department of Chemistry, East China Normal University, Shanghai 200062 (China); Wang Zhongchuan [Department of Anorectal Surgery, Xinhua Hospital, Affiliated to School of Medicine of Shanghai Jiaotong University, Shanghai 200092 (China); Zhang Wen, E-mail: wzhang@chem.ecnu.edu.cn [Department of Chemistry, East China Normal University, Shanghai 200062 (China)

    2011-11-30

    Graphical abstract: In this paper, we reported a novel dual enzymatic-biosensor for simultaneous determination of glucose and cholesterol in serum and peritoneal macrophages (PMs) of diabetic mice to evaluate the diabetes-accelerated atherosclerosis risk. The biosensor was firstly modified with a poly-thionine (PTH) film as electron transfer mediator (ETM), then the gold nanoparticles (GNPs) were covered on the surface of PTH to act as tiny conduction centers for facilitating the electron transfer between enzymes and electrode. The schematic of the dual biosensor is shown in figure. The developed dual biosensor had good electrocatalytic activity toward the oxidations of glucose and cholesterol, exhibited a linear range from 0.008 mM to 6.0 mM for glucose with a detection limit of 2.0 {mu}M, and a linear range from 0.002 mM to 1.0 mM for cholesterol with a detection limit of 0.6 {mu}M. The results of the diabetic mice demonstrated that the cholesterol level was not changed obviously with the increase of glucose level in serum, while the cholesterol level was enhanced together with the increase of the glucose level in PMs. Previous studies have shown that the large accumulation of cholesterol in macrophage could lead to macrophage foam cell formation, the hallmark of early atherosclerosis. These findings indicated the possibility that high glucose induced by diabetes might increase the macrophage cholesterol level to further accelerate atherosclerosis development. Highlights: Black-Right-Pointing-Pointer A novel biosensor was developed to determine glucose and cholesterol simultaneously. Black-Right-Pointing-Pointer The dual enzymatic-biosensor has good selectivity and high sensitivity. Black-Right-Pointing-Pointer We determined glucose and cholesterol in the real samples of diabetic mice. Black-Right-Pointing-Pointer The results showed that high glucose might increase the macrophage cholesterol level. Black-Right-Pointing-Pointer It provided useful experimental

  16. Late Endosomal Cholesterol Accumulation Leads to Impaired Intra-Endosomal Trafficking

    OpenAIRE

    Komla Sobo; Isabelle Le Blanc; Pierre-Philippe Luyet; Marc Fivaz; Charles Ferguson; Parton, Robert G.; Jean Gruenberg; Gisou Van Der Goot, F.

    2007-01-01

    BACKGROUND: Pathological accumulation of cholesterol in late endosomes is observed in lysosomal storage diseases such as Niemann-Pick type C. We here analyzed the effects of cholesterol accumulation in NPC cells, or as phenocopied by the drug U18666A, on late endosomes membrane organization and dynamics. METHODOLOGY/PRINCIPAL FINDINGS: Cholesterol accumulation did not lead to an increase in the raft to non-raft membrane ratio as anticipated. Strikingly, we observed a 2-3 fold increase in the ...

  17. Cholesterol accumulation in prostate cancer: a classic observation from a modern perspective.

    Science.gov (United States)

    Krycer, James Robert; Brown, Andrew John

    2013-04-01

    Prostate cancer (PCa) is the most common cancer in men in developed countries. Epidemiological studies have associated high blood-cholesterol levels with an increased risk of PCa, whilst cholesterol-lowering drugs (statins) reduce the risk of advanced PCa. Furthermore, normal prostate epithelial cells have an abnormally high cholesterol content, with cholesterol levels increasing further during progression to PCa. In this review, we explore why and how this occurs. Concurrent to this observation, intense efforts have been expended in cardiovascular research to better understand the regulators of cholesterol homeostasis. Here, we apply this knowledge to elucidate the molecular mechanisms driving the accumulation of cholesterol in PCa. For instance, recent evidence from our group and others shows that major signalling players in prostate growth and differentiation, such as androgens and Akt, modulate the key transcriptional regulators of cholesterol homeostasis to enhance cholesterol levels. This includes adjusting central carbon metabolism to sustain greater lipid synthesis. Perturbations in cholesterol homeostasis appear to be maintained even when PCa approaches the advanced, 'castration-resistant' state. Overall, this provides a link between cholesterol accumulation and PCa cell growth. Given there is currently no cure for castration-resistant PCa, could cholesterol metabolism be a novel target for PCa therapy? Overall, this review presents a picture that cholesterol metabolism is important for PCa development: growth-promoting factors stimulate cholesterol accumulation, which in turn presents a possible target for chemotherapy. Consequently, we recommend future investigations, both to better elucidate the mechanisms driving this accumulation and applying it in novel chemotherapeutic strategies.

  18. The dynamin chemical inhibitor dynasore impairs cholesterol trafficking and sterol-sensitive genes transcription in human HeLa cells and macrophages.

    Directory of Open Access Journals (Sweden)

    Emmanuelle Girard

    Full Text Available Intracellular transport of cholesterol contributes to the regulation of cellular cholesterol homeostasis by mechanisms that are yet poorly defined. In this study, we characterized the impact of dynasore, a recently described drug that specifically inhibits the enzymatic activity of dynamin, a GTPase regulating receptor endocytosis and cholesterol trafficking. Dynasore strongly inhibited the uptake of low-density lipoprotein (LDL in HeLa cells, and to a lower extent in human macrophages. In both cell types, dynasore treatment led to the abnormal accumulation of LDL and free cholesterol (FC within the endolysosomal network. The measure of cholesterol esters (CE further showed that the delivery of regulatory cholesterol to the endoplasmic reticulum (ER was deficient. This resulted in the inhibition of the transcriptional control of the three major sterol-sensitive genes, sterol-regulatory element binding protein 2 (SREBP-2, 3-hydroxy-3-methyl-coenzymeA reductase (HMGCoAR, and low-density lipoprotein receptor (LDLR. The sequestration of cholesterol in the endolysosomal compartment impaired both the active and passive cholesterol efflux in HMDM. Our data further illustrate the importance of membrane trafficking in cholesterol homeostasis and validate dynasore as a new pharmacological tool to study the intracellular transport of cholesterol.

  19. Arctigenin promotes cholesterol efflux from THP-1 macrophages through PPAR-γ/LXR-α signaling pathway

    Energy Technology Data Exchange (ETDEWEB)

    Xu, Xiaolin [Department of Cardiothoracic Surgery, Huashan Hospital, Fudan University, Shanghai 200032 (China); Li, Qian [Department of Integrative Medicine and Neurobiology, School of Basic Medical Sciences, Shanghai Medical College, Fudan University, Shanghai (China); Pang, Liewen; Huang, Guoqian; Huang, Jiechun; Shi, Meng; Sun, Xiaotian [Department of Cardiothoracic Surgery, Huashan Hospital, Fudan University, Shanghai 200032 (China); Wang, Yiqing, E-mail: yiqingwangbiopaper@163.com [Department of Cardiothoracic Surgery, Huashan Hospital, Fudan University, Shanghai 200032 (China)

    2013-11-15

    Highlights: •Arctigenin enhanced cholesterol efflux in oxLDL-loaded THP-1 macrophages. •The expression of ABCA1, ABCG1 and apoE was upregulated in arctigenin-treated cells. •Arctigenin promoted the expression of PPAR-γ and LXR-α. •Inhibition of PPAR-γ or LXR-α reversed arctigenin-mediated biological effects. •Arctigenin promotes cholesterol efflux via activation of PPAR-γ/LXR-α/ABCA1 pathway. -- Abstract: Cholesterol efflux from macrophages is a critical mechanism to prevent the development of atherosclerosis. Here, we sought to investigate the effects of arctigenin, a bioactive component of Arctium lappa, on the cholesterol efflux in oxidized low-density lipoprotein (oxLDL)-loaded THP-1 macrophages. Our data showed that arctigenin significantly accelerated apolipoprotein A-I- and high-density lipoprotein-induced cholesterol efflux in both dose- and time-dependent manners. Moreover, arctigenin treatment enhanced the expression of ATP binding cassette transporter A1 (ABCA1), ABCG1, and apoE, all of which are key molecules in the initial step of cholesterol efflux, at both mRNA and protein levels. Arctigenin also caused a concentration-dependent elevation in the expression of peroxisome proliferator-activated receptor-gamma (PPAR-γ) and liver X receptor-alpha (LXR-α). The arctigenin-mediated induction of ABCA1, ABCG1, and apoE was abolished by specific inhibition of PPAR-γ or LXR-α using small interfering RNA technology. Our results collectively indicate that arctigenin promotes cholesterol efflux in oxLDL-loaded THP-1 macrophages through upregulation of ABCA1, ABCG1 and apoE, which is dependent on the enhanced expression of PPAR-γ and LXR-α.

  20. The macrophage and its related cholesterol efflux as a HDL function index in atherosclerosis.

    Science.gov (United States)

    Yamamoto, Suguru; Narita, Ichiei; Kotani, Kazuhiko

    2016-06-01

    The macrophage and its related cholesterol efflux are considered to be a key player in atherosclerotic formation in relation to the function of high-density lipoprotein (HDL). The HDL function can be evaluated by the reaction between lipid-loaded macrophages and lipid-acceptors in the HDL fraction from the plasma, apolipoprotein B-depleted serum, and/or whole serum/plasma. Recent studies have reported that an impaired cholesterol efflux of HDL is observed in patients with cardiometabolic diseases, such as dyslipidemia, diabetes mellitus, and chronic kidney disease. A population-based cohort study has reported an inverse association between the cholesterol efflux capacity of HDL and the incidence of atherosclerotic disease, regardless of the serum HDL-cholesterol level. Moreover, in this paper, when we summarized several clinical interventional studies of statin treatment that examined cholesterol efflux, a potential increase in the efflux in patients treated with statins was implied. However, the effect was not fully defined in the current situation because of the small sample sizes, lack of a unified protocol for measuring the efflux, and short-term intervention periods without cardiovascular outcomes in available studies. Further investigation is necessary to determine the effect of drugs on cholesterol efflux. With additional advanced studies, cholesterol efflux is a promising laboratory index to understand the HDL function.

  1. Chlorogenic acid protects against atherosclerosis in ApoE-/- mice and promotes cholesterol efflux from RAW264.7 macrophages.

    Science.gov (United States)

    Wu, Chongming; Luan, Hong; Zhang, Xue; Wang, Shuai; Zhang, Xiaopo; Sun, Xiaobo; Guo, Peng

    2014-01-01

    Chlorogenic acid (CGA) is one of the most abundant polyphenols in the human diet and is suggested to be a potential antiatherosclerotic agent due to its proposed hypolipidemic, anti-inflammatory and antioxidative properties. The aim of this study was to evaluate the effect of CGA on atherosclerosis development in ApoE(-/-) mice and its potential mechanism. ApoE(-/-) mice were fed a cholesterol-rich diet without (control) or with CGA (200 and 400 mg/kg) or atorvastatin (4 mg/kg) for 12 weeks. During the study plasma lipid and inflammatory parameters were determined. Treatment with CGA (400 mg/kg) reduced atherosclerotic lesion area and vascular dilatation in the aortic root, comparable to atorvastatin. CGA (400 mg/kg) also significantly decreased plasma levels of total cholesterol, triglycerides and low-density lipoprotein-cholesterol as well as inflammatory markers. Supplementation with CGA or CGA metabolites-containing serum suppressed oxidized low-density lipoprotein (oxLDL)-induced lipid accumulation and stimulated cholesterol efflux from RAW264.7 cells. CGA significantly increased the mRNA levels of PPARγ, LXRα, ABCA1 and ABCG1 as well as the transcriptional activity of PPARγ. Cholesterol efflux assay showed that three major metabolites, caffeic, ferulic and gallic acids, significantly stimulated cholesterol efflux from RAW264.7 cells. These results suggest that CGA potently reduces atherosclerosis development in ApoE(-/-) mice and promotes cholesterol efflux from RAW264.7 macrophages. Caffeic, ferulic and gallic acids may be the potential active compounds accounting for the in vivo effect of CGA.

  2. Chlorogenic acid protects against atherosclerosis in ApoE-/- mice and promotes cholesterol efflux from RAW264.7 macrophages.

    Directory of Open Access Journals (Sweden)

    Chongming Wu

    Full Text Available Chlorogenic acid (CGA is one of the most abundant polyphenols in the human diet and is suggested to be a potential antiatherosclerotic agent due to its proposed hypolipidemic, anti-inflammatory and antioxidative properties. The aim of this study was to evaluate the effect of CGA on atherosclerosis development in ApoE(-/- mice and its potential mechanism. ApoE(-/- mice were fed a cholesterol-rich diet without (control or with CGA (200 and 400 mg/kg or atorvastatin (4 mg/kg for 12 weeks. During the study plasma lipid and inflammatory parameters were determined. Treatment with CGA (400 mg/kg reduced atherosclerotic lesion area and vascular dilatation in the aortic root, comparable to atorvastatin. CGA (400 mg/kg also significantly decreased plasma levels of total cholesterol, triglycerides and low-density lipoprotein-cholesterol as well as inflammatory markers. Supplementation with CGA or CGA metabolites-containing serum suppressed oxidized low-density lipoprotein (oxLDL-induced lipid accumulation and stimulated cholesterol efflux from RAW264.7 cells. CGA significantly increased the mRNA levels of PPARγ, LXRα, ABCA1 and ABCG1 as well as the transcriptional activity of PPARγ. Cholesterol efflux assay showed that three major metabolites, caffeic, ferulic and gallic acids, significantly stimulated cholesterol efflux from RAW264.7 cells. These results suggest that CGA potently reduces atherosclerosis development in ApoE(-/- mice and promotes cholesterol efflux from RAW264.7 macrophages. Caffeic, ferulic and gallic acids may be the potential active compounds accounting for the in vivo effect of CGA.

  3. ABC-transporters and lipid transfer proteins : important players in macrophage cholesterol homeostasis and atherosclerosis

    NARCIS (Netherlands)

    Ye, Dan

    2008-01-01

    Local modulation of macrophage cholesterol metabolism in the arterial wall and systemic regulation of lipoprotein metabolism (LDL-lowering and/or HDL-raising) are both attractive targets for future drug design for the prevention of atherosclerosis. As described in this thesis, bone marrow transplant

  4. 17 beta-estradiol but not the phytoestrogen naringenin attenuates aortic cholesterol accumulation in WHHL rabbits

    DEFF Research Database (Denmark)

    Mortensen, Alicja; Breinholt, V.; Dalsgaard, T.;

    2001-01-01

    .20% naringenin, for 16 weeks. The uterine weight was increased (P cholesterol and triglycerides were not different from those in the controls, In lipoproteins, HDL...... cholesterol was increased (P cholesterol accumulation was decreased (P ... but the ratio of intima to media and area of intima in ascending, thoracic, and abdominal aorta were not significantly different. In the naringenin group the only differences, compared with the control group, were increased LDL cholesterol (P

  5. Arctigenin promotes cholesterol efflux from THP-1 macrophages through PPAR-γ/LXR-α signaling pathway.

    Science.gov (United States)

    Xu, Xiaolin; Li, Qian; Pang, Liewen; Huang, Guoqian; Huang, Jiechun; Shi, Meng; Sun, Xiaotian; Wang, Yiqing

    2013-11-15

    Cholesterol efflux from macrophages is a critical mechanism to prevent the development of atherosclerosis. Here, we sought to investigate the effects of arctigenin, a bioactive component of Arctium lappa, on the cholesterol efflux in oxidized low-density lipoprotein (oxLDL)-loaded THP-1 macrophages. Our data showed that arctigenin significantly accelerated apolipoprotein A-I- and high-density lipoprotein-induced cholesterol efflux in both dose- and time-dependent manners. Moreover, arctigenin treatment enhanced the expression of ATP binding cassette transporter A1 (ABCA1), ABCG1, and apoE, all of which are key molecules in the initial step of cholesterol efflux, at both mRNA and protein levels. Arctigenin also caused a concentration-dependent elevation in the expression of peroxisome proliferator-activated receptor-gamma (PPAR-γ) and liver X receptor-alpha (LXR-α). The arctigenin-mediated induction of ABCA1, ABCG1, and apoE was abolished by specific inhibition of PPAR-γ or LXR-α using small interfering RNA technology. Our results collectively indicate that arctigenin promotes cholesterol efflux in oxLDL-loaded THP-1 macrophages through upregulation of ABCA1, ABCG1 and apoE, which is dependent on the enhanced expression of PPAR-γ and LXR-α.

  6. Lysosomal cholesterol accumulation : driver on the road to inflammation during atherosclerosis and non-alcoholic steatohepatitis

    NARCIS (Netherlands)

    Hendrikx, T.; Walenbergh, S. M. A.; Hofker, M. H.; Shiri-Sverdlov, R.

    2014-01-01

    Many studies show an association between the accumulation of cholesterol inside lysosomes and the progression towards inflammatory disease states that are closely related to obesity. While in the past, the knowledge regarding lysosomal cholesterol accumulation was limited to its association with pla

  7. β Common Receptor Mediates Erythropoietin-Conferred Protection on OxLDL-Induced Lipid Accumulation and Inflammation in Macrophages

    Directory of Open Access Journals (Sweden)

    Tzong-Shyuan Lee

    2015-01-01

    Full Text Available Erythropoietin (EPO, the key factor for erythropoiesis, also protects macrophage foam cells from lipid accumulation, yet the definitive mechanisms are not fully understood. β common receptor (βCR plays a crucial role in the nonhematopoietic effects of EPO. In the current study, we investigated the role of βCR in EPO-mediated protection in macrophages against oxidized low-density lipoprotein- (oxLDL- induced deregulation of lipid metabolism and inflammation. Here, we show that βCR expression was mainly in foamy macrophages of atherosclerotic aortas from apolipoprotein E-deficient mice. Results of confocal microscopy and immunoprecipitation analyses revealed that βCR was colocalized and interacted with EPO receptor (EPOR in macrophages. Inhibition of βCR activation by neutralizing antibody or small interfering RNA (siRNA abolished the EPO-conferred protection in oxLDL-induced lipid accumulation. Furthermore, EPO-promoted cholesterol efflux and upregulation of ATP-binding cassette (ABC transporters ABCA1 and ABCG1 were prevented by pretreatment with βCR neutralizing antibody or βCR siRNA. Additionally, blockage of βCR abrogated the EPO-conferred anti-inflammatory action on oxLDL-induced production of macrophage inflammatory protein-2. Collectively, our findings suggest that βCR may play an important role in the beneficial effects of EPO against oxLDL-elicited dysfunction of macrophage foam cells.

  8. Cholesterol Oxidase Binds TLR2 and Modulates Functional Responses of Human Macrophages

    Directory of Open Access Journals (Sweden)

    Katarzyna Bednarska

    2014-01-01

    Full Text Available Cholesterol oxidase (ChoD is considered to be an important virulence factor for Mycobacterium tuberculosis (Mtb, but its influence on macrophage activity is unknown. Here we used Nocardia erythropolis ChoD, which is very similar to the Mtb enzyme (70% identity at the amino-acid level, to evaluate the impact of bacterial ChoD on the activity of THP-1-derived macrophages in vitro. We found that ChoD decreased the surface expression of Toll-like receptor type 2 (TLR2 and complement receptor 3 (CR3 on these macrophages. Flow cytometry and confocal microscopy showed that ChoD competed with lipoteichoic acid for ligand binding sites on TLR2 but not on CR3, suggesting that ChoD signaling is mediated via TLR2. Binding of ChoD to the membrane of macrophages had diverse effects on the activity of macrophages, activating p38 mitogen activated kinase and stimulating production of a large amount of interleukin-10. Moreover, ChoD primed macrophages to enhance the production of reactive oxygen species in response to the phorbol myristate acetate, which was reduced by “switching off” TLR-derived signaling through interleukin-1 receptor-associated kinases 1 and 4 inhibition. Our study revealed that ChoD interacts directly with macrophages via TLR2 and influences the biological activity of macrophages during the development of the initial response to infection.

  9. Cholesterol efflux pathways regulate myelopoiesis: A potential link to altered macrophage function in atherosclerosis

    Directory of Open Access Journals (Sweden)

    Andrew James Murphy

    2014-10-01

    Full Text Available Atherosclerotic cardiovascular disease (CVD is a chronic inflammatory disease of the blood vessels that can lead to myocardial infarction or stroke. The major cell in the atherosclerotic lesion, the macrophage is thought to be an important contributor to the production of inflammatory mediators that exacerbate this disease. Macrophages are generally derived from circulating monocytes, which are in turn produced by hematopoietic stem and multipotential progenitor cells (HSPCs in the bone marrow and other medullary organs. Recent studies suggest that disruption in cholesterol homeostasis or prolonged exposure to a hypercholesterolemic environment can influence HSPCs to over-produce monocytes, resulting in monocytosis. These monocytes may carry a pre-programed ability to become M1-like macrophages once they enter the atherosclerotic lesion. Future studies may help to differentiate the role of such pre-programming versus responses to local environmental cues in determining M1, M2 or other macrophage phenotypes in atherosclerotic lesions.

  10. Cholesterol glucosylation by Helicobacter pylori delays internalization and arrests phagosome maturation in macrophages.

    Science.gov (United States)

    Du, Shin-Yi; Wang, Hung-Jung; Cheng, Hsin-Hung; Chen, Sheng-De; Wang, Lily Hui-Ching; Wang, Wen-Ching

    2016-10-01

    Helicobacter pylori colonizes the human stomach and contributes to chronic inflammation of the gastric mucosa. H. pylori persistence occurs because of insufficient eradication by phagocytic cells. A key factor of H. pylori, cholesterol-α-glucosyltransferase encoded by capJ that extracts host cholesterol and converts it to cholesteryl glucosides, is important to evade host immunity. Here, we examined whether phagocytic trafficking in macrophages was perturbed by capJ-carrying H. pylori. J774A.1 cells were infected with H. pylori at a multiplicity of infection of 50. Live-cell imaging and confocal microscopic analysis were applied to monitor the phagocytic trafficking events. The viability of H. pylori inside macrophages was determined by using gentamicin colony-forming unit assay. The phagocytic routes were characterized by using trafficking-intervention compounds. Wild type (WT) H. pylori exhibited more delayed entry into macrophages and also arrested phagosome maturation more than did capJ knockout mutant. Pretreatment of genistein and LY294002 prior to H. pylori infection reduced the internalization of WT but not capJ-knockout H. pylori in macrophages. Cholesterol glucosylation by H. pylori interferes with phagosome trafficking via a lipid-raft and PI3K-dependent manner, which retards engulfment of bacteria for prolonged intracellular survival of H. pylori. Copyright © 2014. Published by Elsevier B.V.

  11. Voluntary exercise increases cholesterol efflux but not macrophage reverse cholesterol transport in vivo in mice

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    Kuipers Folkert

    2010-07-01

    Full Text Available Abstract Physical exercise beneficially impacts on the plasma lipoprotein profile as well as on the incidence of cardiovascular events and is therefore recommended in primary and secondary prevention strategies against atherosclerotic cardiovascular disease. However, the underlying mechanisms of the protective effect of exercise remain largely unknown. Therefore, the present study tested the hypothesis that voluntary exercise in mice impacts on cholesterol efflux and in vivo reverse cholesterol transport (RCT. After two weeks of voluntary wheel running (average 10.1 ± 1.4 km/day plasma triglycerides were lower (p

  12. Cholesterol efflux from THP-1 macrophages is impaired by the fatty acid component from lipoprotein hydrolysis by lipoprotein lipase

    Energy Technology Data Exchange (ETDEWEB)

    Yang, Yanbo; Thyagarajan, Narmadaa; Coady, Breanne M.; Brown, Robert J., E-mail: rbrown@mun.ca

    2014-09-05

    Highlights: • Lipoprotein hydrolysis products were produced by lipoprotein lipase. • Hydrolysis products lowers expression of macrophage cholesterol transporters. • Hydrolysis products reduces expression of select nuclear receptors. • Fatty acid products lowers cholesterol transporters and select nuclear receptors. • Fatty acid products reduces cholesterol efflux from macrophages. - Abstract: Lipoprotein lipase (LPL) is an extracellular lipase that primarily hydrolyzes triglycerides within circulating lipoproteins. Macrophage LPL contributes to atherogenesis, but the mechanisms behind it are poorly understood. We hypothesized that the products of lipoprotein hydrolysis generated by LPL promote atherogenesis by inhibiting the cholesterol efflux ability by macrophages. To test this hypothesis, we treated human THP-1 macrophages with total lipoproteins that were hydrolyzed by LPL and we found significantly reduced transcript levels for the cholesterol transporters ATP binding cassette transporter A1 (ABCA1), ABCG1, and scavenger receptor BI. These decreases were likely due to significant reductions for the nuclear receptors liver-X-receptor-α, peroxisome proliferator activated receptor (PPAR)-α, and PPAR-γ. We prepared a mixture of free fatty acids (FFA) that represented the ratios of FFA species within lipoprotein hydrolysis products, and we found that the FFA mixture also significantly reduced cholesterol transporters and nuclear receptors. Finally, we tested the efflux of cholesterol from THP-1 macrophages to apolipoprotein A-I, and we found that the treatment of THP-1 macrophages with the FFA mixture significantly attenuated cholesterol efflux. Overall, these data show that the FFA component of lipoprotein hydrolysis products generated by LPL may promote atherogenesis by inhibiting cholesterol efflux, which partially explains the pro-atherogenic role of macrophage LPL.

  13. Data related to inflammation and cholesterol deposition triggered by macrophages exposition to modified LDL

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    Juan Toledo

    2016-09-01

    Full Text Available This article supports experimental evidence on the time-dependent effect on gene expression related to inflammation and cholesterol deposition in lipid-loaded cells. The cells employed were human monocytes THP1 line transformed into macrophages by treatment with phorbol esters. Macrophages were treated at different times with oxidized low density lipoprotein (Ox-LDL and then gene expression was measured. We also include data about the different types of oxidized lipoprotein obtained (low, media or high oxidation for differential exposure with Cu ions. These data include characterization to lipid and protein peroxidative damage and also quantification of cell viability by exposure to native and modified LDL. The present article complements data published in “Decreased OxLDL uptake and cholesterol efflux in THP1 cells elicited by cortisol and by cortisone through 11β-hydroxysteroid dehydrogenase type 1” Ledda et al. (in press [1].

  14. Data related to inflammation and cholesterol deposition triggered by macrophages exposition to modified LDL.

    Science.gov (United States)

    Toledo, Juan; Esteve, Montserrat; Grasa, Mar; Ledda, Angelo; Garda, Horacio; Gulfo, José; Ludovico, Ivo Díaz; Ramella, Nahuel; Gonzalez, Marina

    2016-09-01

    This article supports experimental evidence on the time-dependent effect on gene expression related to inflammation and cholesterol deposition in lipid-loaded cells. The cells employed were human monocytes THP1 line transformed into macrophages by treatment with phorbol esters. Macrophages were treated at different times with oxidized low density lipoprotein (Ox-LDL) and then gene expression was measured. We also include data about the different types of oxidized lipoprotein obtained (low, media or high oxidation) for differential exposure with Cu ions. These data include characterization to lipid and protein peroxidative damage and also quantification of cell viability by exposure to native and modified LDL. The present article complements data published in "Decreased OxLDL uptake and cholesterol efflux in THP1 cells elicited by cortisol and by cortisone through 11β-hydroxysteroid dehydrogenase type 1" Ledda et al. (in press) [1].

  15. Late endosomal cholesterol accumulation leads to impaired intra-endosomal trafficking.

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    Komla Sobo

    Full Text Available BACKGROUND: Pathological accumulation of cholesterol in late endosomes is observed in lysosomal storage diseases such as Niemann-Pick type C. We here analyzed the effects of cholesterol accumulation in NPC cells, or as phenocopied by the drug U18666A, on late endosomes membrane organization and dynamics. METHODOLOGY/PRINCIPAL FINDINGS: Cholesterol accumulation did not lead to an increase in the raft to non-raft membrane ratio as anticipated. Strikingly, we observed a 2-3 fold increase in the size of the compartment. Most importantly, properties and dynamics of late endosomal intralumenal vesicles were altered as revealed by reduced late endosomal vacuolation induced by the mutant pore-forming toxin ASSP, reduced intoxication by the anthrax lethal toxin and inhibition of infection by the Vesicular Stomatitis Virus. CONCLUSIONS/SIGNIFICANCE: These results suggest that back fusion of intralumenal vesicles with the limiting membrane of late endosomes is dramatically perturbed upon cholesterol accumulation.

  16. Piperine inhibits ABCA1 degradation and promotes cholesterol efflux from THP-1-derived macrophages

    Science.gov (United States)

    Wang, Limei; Palme, Veronika; Rotter, Susanne; Schilcher, Nicole; Cukaj, Malsor; Wang, Dongdong; Ladurner, Angela; Heiss, Elke H.; Stangl, Herbert; Dirsch, Verena M.; Atanasov, Atanas G.

    2017-01-01

    Scope Increased macrophage cholesterol efflux (ChE) is considered to have anti-atherosclerotic effect counteracting cardiovascular disease. The principle pungent ingredient of the fruits of Piper nigrum, piperine, is identified in this study as a ChE inducer in THP-1-derived macrophages, and mechanisms underlying this effect are explored. Methods and results Without affecting cell viability, piperine concentration-dependently enhances ChE in THP-1-derived macrophages from 25 to 100 μM. The expression level of the key cholesterol transporter protein ATP-binding cassette transporter A1 (ABCA1) is significantly upregulated by piperine, as revealed by western blot analyses. However, two other ChE-mediating transporter proteins, ATP-binding cassette transporter G1 (ABCG1) and scavenger receptor class B member 1 (SR-B1), remain unaffected. Piperine exerts no influence on ABCA1 mRNA levels, but significantly inhibits the degradation of ABCA1, as evident by an increased half-life of the protein in the presence of cycloheximide. Furthermore, it is found that piperine likely interferes with the calpain-mediated ABCA1 degradation pathway and exhibits significant inhibition of calpain activity. Conclusion Our findings suggest that piperine promotes ChE in THP-1-derived macrophages by upregulation of ABCA1, which might be mediated by inhibition of calpain activity. This novel bioactivity makes the dietary constituent piperine a good candidate to be further explored for therapeutic or preventive applications in the context of atherosclerosis. PMID:27862930

  17. Cholesterol efflux from THP-1 macrophages is impaired by the fatty acid component from lipoprotein hydrolysis by lipoprotein lipase.

    Science.gov (United States)

    Yang, Yanbo; Thyagarajan, Narmadaa; Coady, Breanne M; Brown, Robert J

    2014-09-05

    Lipoprotein lipase (LPL) is an extracellular lipase that primarily hydrolyzes triglycerides within circulating lipoproteins. Macrophage LPL contributes to atherogenesis, but the mechanisms behind it are poorly understood. We hypothesized that the products of lipoprotein hydrolysis generated by LPL promote atherogenesis by inhibiting the cholesterol efflux ability by macrophages. To test this hypothesis, we treated human THP-1 macrophages with total lipoproteins that were hydrolyzed by LPL and we found significantly reduced transcript levels for the cholesterol transporters ATP binding cassette transporter A1 (ABCA1), ABCG1, and scavenger receptor BI. These decreases were likely due to significant reductions for the nuclear receptors liver-X-receptor-α, peroxisome proliferator activated receptor (PPAR)-α, and PPAR-γ. We prepared a mixture of free fatty acids (FFA) that represented the ratios of FFA species within lipoprotein hydrolysis products, and we found that the FFA mixture also significantly reduced cholesterol transporters and nuclear receptors. Finally, we tested the efflux of cholesterol from THP-1 macrophages to apolipoprotein A-I, and we found that the treatment of THP-1 macrophages with the FFA mixture significantly attenuated cholesterol efflux. Overall, these data show that the FFA component of lipoprotein hydrolysis products generated by LPL may promote atherogenesis by inhibiting cholesterol efflux, which partially explains the pro-atherogenic role of macrophage LPL.

  18. Lactobacillus acidophilus K301 Inhibits Atherogenesis via Induction of 24 (S), 25-Epoxycholesterol-Mediated ABCA1 and ABCG1 Production and Cholesterol Efflux in Macrophages.

    Science.gov (United States)

    Hong, Yi-Fan; Kim, Hangeun; Kim, Hye Sun; Park, Woo Jung; Kim, Joo-Yun; Chung, Dae Kyun

    2016-01-01

    Lactobacillus acidophilus species are well-known probiotics with the beneficial activity of regulating cholesterol levels. In this study, we showed that L. acidophilus K301 reduced the level of cholesterol through reverse transport in macrophages. L. acidophilus K301 upregulated the mRNA and protein levels of genes such as ATP-binding cassette A1 (ABCA1) and ATP-binding cassette G1 (ABCG1) under the control of liver X receptor (LXR), resulting in increased apoA-I-dependent cholesterol efflux in phorbol 12-myristate 13-acetate (PMA)-differentiated THP-1 cells. L. acidophilus K301 induced both ABCA1 and ABCG1 through the endogenous LXR agonist 24(S), 25-epoxcycholesterol, which is synthesized by intracellular cholesterol synthetic pathways. In vivo studies using L. acidophilus K301-treated ApoE-/- mice showed reduced accumulation of lipoproteins in the arterial lumen. The inhibitory effects of L. acidophilus K301 on accumulation of lipoprotein in atherosclerotic plaques were mediated by the induction of squalene reductase (SQLE) and oxidosqualene cyclase (OSC) and resulted in ABCA1-mediated cholesterol efflux. Taken together, our findings revealed that Lactobacillus acidophilus K301 regulates the expression of genes related to cholesterol reverse transport via the induction of endogenous LXR agonist, suggesting the therapeutic potential of Lactobacillus acidophilus K301 as an anti-atherosclerotic agent.

  19. Vascular lipid accumulation, lipoprotein oxidation and macrophage lipid uptake in hypercholesterolemic zebrafish

    Science.gov (United States)

    Stoletov, Konstantin; Fang, Longhou; Choi, Soo-Ho; Hartvigsen, Karsten; Hansen, Lotte F.; Hall, Chris; Pattison, Jennifer; Juliano, Joseph; Miller, Elizabeth R.; Almazan, Felicidad; Crosier, Phil; Witztum, Joseph L.; Klemke, Richard L.; Miller, Yury I.

    2010-01-01

    Lipid accumulation in arteries induces vascular inflammation and atherosclerosis, the major cause of heart attack and stroke in humans. Extreme hyperlipidemia induced in mice and rabbits enables modeling many aspects of human atherosclerosis, but microscopic examination of plaques is possible only postmortem. Here we report that feeding adult zebrafish (Danio rerio) a high-cholesterol diet (HCD) resulted in hypercholesterolemia, remarkable lipoprotein oxidation and fatty streak formation in the arteries. Feeding an HCD supplemented with a fluorescent cholesteryl ester to optically transparent fli1:EGFP zebrafish larvae in which endothelial cells (EC) express GFP, and using confocal microscopy enabled monitoring vascular lipid accumulation and the EC layer disorganization and thickening in a live animal. The HCD feeding also increased leakage of a fluorescent dextran from the blood vessels. Administering ezetimibe significantly diminished the HCD-induced EC layer thickening and improved its barrier function. Feeding HCD to lyz:DsRed2 larvae in which macrophages and granulocytes express DsRed, resulted in the accumulation of fluorescent myeloid cells in the vascular wall. Using a fluorogenic substrate for phospholipase A2 (PLA2), we observed an increased vascular PLA2 activity in live HCD-fed larvae compared to control larvae. Furthermore, by transplanting genetically modified murine cells into HCD-fed larvae, we demonstrated that toll-like receptor-4 (TLR4) was required for efficient in vivo lipid uptake by macrophages. These results suggest that the novel zebrafish model is suitable for studying temporal characteristics of certain inflammatory processes of early atherogenesis and the in vivo function of vascular cells. PMID:19265037

  20. Free-cholesterol loading does not trigger phase separation of the fluorescent sterol dehydroergosterol in the plasma membrane of macrophages

    DEFF Research Database (Denmark)

    Wüstner, Daniel

    2008-01-01

    membrane distribution of the fluorescent cholesterol-mimicking sterol dehydroergosterol (DHE) was investigated in FC-loaded J774 macrophages. Wide field fluorescence and deconvolution microscopy were combined with quantitative assessment of sterol distribution in straightened plasma membrane image segments...... with increased membrane cholesterol content, sterols do not form a separate phase in the plasma membrane....

  1. Macrophage ABCA5 deficiency influences cellular cholesterol efflux and increases susceptibility to atherosclerosis in female LDLr knockout mice

    Energy Technology Data Exchange (ETDEWEB)

    Ye, Dan, E-mail: y.dan@lacdr.leidenuniv.nl [Division of Biopharmaceutics, LACDR, Leiden University (Netherlands); Meurs, Illiana [Division of Biopharmaceutics, LACDR, Leiden University (Netherlands); Ohigashi, Megumi [Department of Cell Membrane Biology, Institute of Scientific and Industrial Research, Osaka University (Japan); Calpe-Berdiel, Laura; Habets, Kim L.L.; Zhao, Ying [Division of Biopharmaceutics, LACDR, Leiden University (Netherlands); Kubo, Yoshiyuki [Division of Pharmaceutical Sciences, Graduate School of Natural Science and Technology, Kanazawa University (Japan); Yamaguchi, Akihito [Department of Cell Membrane Biology, Institute of Scientific and Industrial Research, Osaka University (Japan); Van Berkel, Theo J.C. [Division of Biopharmaceutics, LACDR, Leiden University (Netherlands); Nishi, Tsuyoshi [Department of Cell Membrane Biology, Institute of Scientific and Industrial Research, Osaka University (Japan); Van Eck, Miranda [Division of Biopharmaceutics, LACDR, Leiden University (Netherlands)

    2010-05-07

    Objectives: To determine the role of macrophage ATP-binding cassette transporter A5 (ABCA5) in cellular cholesterol homeostasis and atherosclerotic lesion development. Methods and results: Chimeras with dysfunctional macrophage ABCA5 (ABCA5{sup -M/-M}) were generated by transplantation of bone marrow from ABCA5 knockout (ABCA5{sup -/-}) mice into irradiated LDLr{sup -/-} mice. In vitro, bone marrow-derived macrophages from ABCA5{sup -M/-M} chimeras exhibited a 29% (P < 0.001) decrease in cholesterol efflux to HDL, whereas a 21% (P = 0.07) increase in cholesterol efflux to apoA-I was observed. Interestingly, expression of ABCA1, but not ABCG1, was up-regulated in absence of functional ABCA5 in macrophages. To induce atherosclerosis, the transplanted LDLr{sup -/-} mice were fed a high-cholesterol Western-type diet (WTD) for 6, 10, or 18 weeks, allowing analysis of effects on initial as well as advanced lesion development. Atherosclerosis development was not affected in male ABCA5{sup -M/-M} chimeras after 6, 10, and 18 weeks WTD feeding. However, female ABCA5{sup -M/-M} chimeras did develop significantly (P < 0.05) larger aortic root lesions as compared with female controls after 6 and 10 weeks WTD feeding. Conclusions: ABCA5 influences macrophage cholesterol efflux, and selective disruption of ABCA5 in macrophages leads to increased atherosclerotic lesion development in female LDLr{sup -/-} mice.

  2. Pitavastatin Differentially Modulates MicroRNA-Associated Cholesterol Transport Proteins in Macrophages.

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    Haijun Zhang

    Full Text Available There is emerging evidence identifying microRNAs (miRNAs as mediators of statin-induced cholesterol efflux, notably through the ATP-binding cassette transporter A1 (ABCA1 in macrophages. The objective of this study was to assess the impact of an HMG-CoA reductase inhibitor, pitavastatin, on macrophage miRNAs in the presence and absence of oxidized-LDL, a hallmark of a pro-atherogenic milieu. Treatment of human THP-1 cells with pitavastatin prevented the oxLDL-mediated suppression of miR-33a, -33b and -758 mRNA in these cells, an effect which was not uniquely attributable to induction of SREBP2. Induction of ABCA1 mRNA and protein by oxLDL was inhibited (30% by pitavastatin, while oxLDL or pitavastatin alone significantly induced and repressed ABCA1 expression, respectively. These findings are consistent with previous reports in macrophages. miRNA profiling was also performed using a miRNA array. We identified specific miRNAs which were up-regulated (122 and down-regulated (107 in THP-1 cells treated with oxLDL plus pitavastatin versus oxLDL alone, indicating distinct regulatory networks in these cells. Moreover, several of the differentially expressed miRNAs identified are functionally associated with cholesterol trafficking (six miRNAs in cells treated with oxLDL versus oxLDL plus pitavastatin. Our findings indicate that pitavastatin can differentially modulate miRNA in the presence of oxLDL; and, our results provide evidence that the net effect on cholesterol homeostasis is mediated by a network of miRNAs.

  3. Leishmania donovani infection enhances lateral mobility of macrophage membrane protein which is reversed by liposomal cholesterol.

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    Moumita Ghosh

    2014-12-01

    Full Text Available The protozoan parasite Leishmania donovani (LD reduces cellular cholesterol of the host possibly for its own benefit. Cholesterol is mostly present in the specialized compartment of the plasma membrane. The relation between mobility of membrane proteins and cholesterol depletion from membrane continues to be an important issue. The notion that leishmania infection alters the mobility of membrane proteins stems from our previous study where we showed that the distance between subunits of IFNγ receptor (R1 and R2 on the cell surface of LD infected cell is increased, but is restored to normal by liposomal cholesterol treatment.We determined the lateral mobility of a membrane protein in normal, LD infected and liposome treated LD infected cells using GFP-tagged PLCδ1 as a probe. The mobility of PLCδ1 was computationally analyzed from the time lapse experiment using boundary distance plot and radial profile movement. Our results showed that the lateral mobility of the membrane protein, which is increased in infection, is restored to normal upon liposomal cholesterol treatment. The results of FRAP experiment lent further credence to the above notion. The membrane proteins are intimately linked with cellular actin and alteration of cellular actin may influence lateral mobility. We found that F-actin is decreased in infection but is restored to normal upon liposomal cholesterol treatment as evident from phalloidin staining and also from biochemical analysis by immunoblotting.To our knowledge this is the first direct demonstration that LD parasites during their intracellular life cycle increases lateral mobility of membrane proteins and decreases F-actin level in infected macrophages. Such defects may contribute to ineffective intracellular signaling and other cellular functions.

  4. Leishmania donovani activates SREBP2 to modulate macrophage membrane cholesterol and mitochondrial oxidants for establishment of infection.

    Science.gov (United States)

    Mukherjee, Madhuchhanda; Basu Ball, Writoban; Das, Pijush K

    2014-10-01

    Establishment of infection by an intracellular pathogen depends on successful internalization with a concomitant neutralization of host defense machinery. Leishmania donovani, an intramacrophage pathogen, targets host SREBP2, a critical transcription factor, to regulate macrophage plasma membrane cholesterol and mitochondrial reactive oxygen species generation, favoring parasite invasion and persistence. Leishmania infection triggered membrane-raft reorientation-dependent Lyn-PI3K/Akt pathway activation which in turn deactivated GSK3β to stabilize nuclear SREBP2. Moreover, cells perceiving less available intracellular cholesterol due to its sequestration at the plasma membrane resulted in the deregulation of the ER-residing SCAP-SREBP2-Insig circuit thereby assisting increased nuclear translocation of SREBP2. Both increased nuclear transport and stabilization of SREBP2 caused HMGCR-catalyzed cholesterol biosynthesis-mediated plasma membrane cholesterol enrichment leading to decreased membrane-fluidity and plausibly assisting delay in phagosomal acidification. Parasite survival ensuing entry was further ensured by SREBP2-dependent transcriptional up-regulation of UCP2, which suppressed mitochondrial ROS generation, one of the primary microbicidal molecules in macrophages recognized for its efficacy against Leishmania. Functional knock-down of SREBP2 both in vitro and in vivo was associated with reduction in macrophage plasma membrane cholesterol, increased ROS production and lower parasite survival. To our knowledge, this study, for the first time, reveals that Leishmania exploits macrophage cholesterol-dependent SREBP2 circuit to facilitate its entry and survival within the host.

  5. Loss of CD73 prevents accumulation of alternatively activated macrophages and the formation of prefibrotic macrophage clusters in irradiated lungs.

    Science.gov (United States)

    de Leve, Simone; Wirsdörfer, Florian; Cappuccini, Federica; Schütze, Alexandra; Meyer, Alina V; Röck, Katharina; Thompson, Linda F; Fischer, Jens W; Stuschke, Martin; Jendrossek, Verena

    2017-07-01

    While radiotherapy is a mainstay for cancer therapy, pneumonitis and fibrosis constitute dose-limiting side effects of thorax and whole body irradiation. So far, the contribution of immune cells to disease progression is largely unknown. Here we studied the role of ecto-5'-nucelotidase (CD73)/adenosine-induced changes in the myeloid compartment in radiation-induced lung fibrosis. C57BL/6 wild-type or CD73(-/-) mice received a single dose of whole thorax irradiation (WTI, 15 Gy). Myeloid cells were characterized in flow cytometric, histologic, and immunohistochemical analyses as well as RNA analyses. WTI induced a pronounced reduction of alveolar macrophages in both strains that recovered within 6 wk. Fibrosis development in wild-type mice was associated with a time-dependent deposition of hyaluronic acid (HA) and increased expression of markers for alternative activation on alveolar macrophages. These include the antiinflammatory macrophage mannose receptor and arginase-1. Further, macrophages accumulated in organized clusters and expressed profibrotic mediators at ≥25 wk after irradiation (fibrotic phase). Irradiated CD73(-/-) mice showed an altered regulation of components of the HA system and no clusters of alternatively activated macrophages. We speculate that accumulation of alternatively activated macrophages in organized clusters represents the origins of fibrotic foci after WTI and is promoted by a cross-talk between HA, CD73/adenosine signaling, and other profibrotic mediators.-De Leve, S., Wirsdörfer, F., Cappuccini, F., Schütze, A., Meyer, A. V., Röck, K., Thompson, L. F., Fischer, J. W., Stuschke, M., Jendrossek, V. Loss of CD73 prevents accumulation of alternatively activated macrophages and the formation of prefibrotic macrophage clusters in irradiated lungs. © FASEB.

  6. Necroptosis-like Neuronal Cell Death Caused by Cellular Cholesterol Accumulation.

    Science.gov (United States)

    Funakoshi, Takeshi; Aki, Toshihiko; Tajiri, Masateru; Unuma, Kana; Uemura, Koichi

    2016-11-25

    Aberrant cellular accumulation of cholesterol is associated with neuronal lysosomal storage disorders such as Niemann-Pick disease Type C (NPC). We have shown previously that l-norephedrine (l-Nor), a sympathomimetic amine, induces necrotic cell death associated with massive cytoplasmic vacuolation in SH-SY5Y human neuroblastoma cells. To reveal the molecular mechanism underling necrotic neuronal cell death caused by l-Nor, we examined alterations in the gene expression profile of cells during l-Nor exposure. DNA microarray analysis revealed that the gene levels for cholesterol transport (LDL receptor and NPC2) as well as cholesterol biosynthesis (mevalonate pathway enzymes) are increased after exposure to 3 mm l-Nor for ∼6 h. Concomitant with this observation, the master transcriptional regulator of cholesterol homeostasis, SREBP-2, is activated by l-Nor. The increase in cholesterol uptake as well as biosynthesis is not accompanied by an increase in cholesterol in the plasma membrane, but rather by aberrant accumulation in cytoplasmic compartments. We also found that cell death by l-Nor can be suppressed by nec-1s, an inhibitor of a regulated form of necrosis, necroptosis. Abrogation of SREBP-2 activation by the small molecule inhibitor betulin or by overexpression of dominant-negative SREBP-2 efficiently reduces cell death by l-Nor. The mobilization of cellular cholesterol in the presence of cyclodextrin also suppresses cell death. These results were also observed in primary culture of striatum neurons. Taken together, our results indicate that the excessive uptake as well as synthesis of cholesterol should underlie neuronal cell death by l-Nor exposure, and suggest a possible link between lysosomal cholesterol storage disorders and the regulated form of necrosis in neuronal cells. © 2016 by The American Society for Biochemistry and Molecular Biology, Inc.

  7. Hypoxanthine induces cholesterol accumulation and incites atherosclerosis in apolipoprotein E-deficient mice and cells.

    Science.gov (United States)

    Ryu, Hye-Myung; Kim, You-Jin; Oh, Eun-Joo; Oh, Se-Hyun; Choi, Ji-Young; Cho, Jang-Hee; Kim, Chan-Duck; Park, Sun-Hee; Kim, Yong-Lim

    2016-11-01

    Reactive oxygen species (ROS) generation during purine metabolism is associated with xanthine oxidase and uric acid. However, the direct effect of hypoxanthine on ROS generation and atherosclerosis has not been evaluated. Smoking and heavy drinking are associated with elevated levels of hypoxanthine. In this study, we investigated the role of hypoxanthine on cholesterol synthesis and atherosclerosis development, particularly in apolipoprotein E (APOE)-deficient mice. The effect of hypoxanthine on the regulation of cholesterol synthesis and atherosclerosis were evaluated in Apoe knockout (KO) mice and cultured HepG2 cells. Hypoxanthine markedly increased serum cholesterol levels and the atherosclerotic plaque area in Apoe KO mice. In HepG2 cells, hypoxanthine increased intracellular ROS production. Hypoxanthine increased cholesterol accumulation and decreased APOE and ATP-binding cassette transporter A1 (ABCA1) mRNA and protein expression in HepG2 cells. Furthermore, H2 O2 also increased cholesterol accumulation and decreased APOE and ABCA1 expression. This effect was partially reversible by treatment with the antioxidant N-acetyl cysteine and allopurinol. Hypoxanthine and APOE knockdown using APOE-siRNA synergistically induced cholesterol accumulation and reduced APOE and ABCA1 expression. Hypoxanthine induces cholesterol accumulation in hepatic cells through alterations in enzymes that control lipid transport and induces atherosclerosis in APOE-deficient cells and mice. These effects are partially mediated through ROS produced in response to hypoxanthine. © 2016 The Authors. Journal of Cellular and Molecular Medicine published by John Wiley & Sons Ltd and Foundation for Cellular and Molecular Medicine.

  8. Free cholesterol accumulation in liver sinusoidal endothelial cells exacerbates acetaminophen hepatotoxicity via TLR9 signaling.

    Science.gov (United States)

    Teratani, Toshiaki; Tomita, Kengo; Suzuki, Takahiro; Furuhashi, Hirotaka; Irie, Rie; Hida, Shigeaki; Okada, Yoshikiyo; Kurihara, Chie; Ebinuma, Hirotoshi; Nakamoto, Nobuhiro; Saito, Hidetsugu; Hibi, Toshifumi; Miura, Soichiro; Hokari, Ryota; Kanai, Takanori

    2017-05-26

    Although obesity is a risk factor for acute liver failure, the pathogenic mechanisms are not yet fully understood. High cholesterol (HC) intake, which often underlies obesity, is suggested to play a role in the mechanism. We aimed to elucidate the effect of a HC diet on acetaminophen-induced acute liver injury, the most frequent cause of acute liver failure in the USA. C57BL/6 Toll-like receptor 9 (TLR9) knockout (Tlr9(-/-)) mice and their Tlr9(+/+) littermates were fed an HC diet for fourweeks and then treated with acetaminophen. Liver sinusoidal endothelial cells (LSECs) were isolated from the mice for in vivo and in vitro analyses. The HC diet exacerbated acetaminophen-induced acute liver injury in a TLR9/inflammasome pathway-dependent manner. LSECs played a major role in the cholesterol loading-induced exacerbation. The accumulation of free cholesterol in the endolysosomes in LSECs enhanced TLR9-mediated signaling, thereby exacerbating the pathology of acetaminophen-induced liver injury through the activation of the TLR9/inflammasome pathway. The accumulation of free cholesterol in LSEC endolysosomes induced a dysfunction of the Rab7 membrane trafficking recycling mechanism, thus disrupting the transport of TLR9 from late endosomes to the lysosomes. Consequently, the level of active TLR9 in the late endosomes increased, thereby enhancing TLR9 signaling in LSECs. HC intake exaggerated acetaminophen-induced acute liver injury via free cholesterol accumulation in LSECs, demonstrating a novel role of free cholesterol as a metabolic factor in TLR9 signal regulation and pathologies of acetaminophen-induced liver injury. Therapeutic approaches may target this pathway. Lay summary: High cholesterol intake exacerbated acetaminophen-induced acute liver injury via the accumulation of free cholesterol in the endolysosomes of liver sinusoidal endothelial cells. This accumulation enhanced Toll-like receptor 9 signaling via impairment of its membrane trafficking mechanism

  9. 27-Oxygenated cholesterol induces expression of CXCL8 in macrophages via NF-κB and CD88

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    Kim, Sun-Mi, E-mail: lala1647@hanmail.net [Department of Pharmacology, Pusan National University, School of Medicine, Yangsan, Gyeongnam 626-870 (Korea, Republic of); Lee, Chung Won, E-mail: vasculardoctorlee@gmail.com [Department of Thoracic and Cardiovascular Surgery, Pusan National University Hospital, Pusan 602-739 (Korea, Republic of); Kim, Bo-Young, E-mail: kimboyoung@pusan.ac.kr [Department of Pharmacology, Pusan National University, School of Medicine, Yangsan, Gyeongnam 626-870 (Korea, Republic of); Jung, Young-Suk, E-mail: youngjung@pusan.ac.kr [College of Pharmacy, Pusan National University, Busan 609-735 (Korea, Republic of); Eo, Seong-Kug, E-mail: vetvirus@chonbuk.ac.kr [College of Veterinary Medicine and Bio-Safety Research Institute, Chonbuk National University, Iksan, Jeonbuk 570-752 (Korea, Republic of); Park, Young Chul, E-mail: ycpark@pusan.ac.kr [Department of Microbiology & Immunology, Pusan National University, School of Medicine, Yangsan, Gyeongnam 626-870 (Korea, Republic of); Kim, Koanhoi, E-mail: koanhoi@pusan.ac.kr [Department of Pharmacology, Pusan National University, School of Medicine, Yangsan, Gyeongnam 626-870 (Korea, Republic of)

    2015-08-07

    We attempted to determine the effects of a milieu rich in cholesterol molecules on expression of chemokine CXCL8. A high-cholesterol diet led to an increased transcription of the IL-8 gene in the arteries and elevated levels of CXCL8 in sera of ApoE{sup −/−} mice, compared with those of wild-type C57BL/6 mice. Treatment of THP-1 monocyte/macrophage cells with 27-hydroxycholesterol (27OHChol) resulted in transcription of the IL-8 gene and increased secretion of its corresponding gene product whereas cholesterol did not induce expression of CXCL8 in THP-1 cells. 27OHChol-induced transcription of the IL-8 gene was blocked by cycloheximide, but not by polymyxin B. Treatment of THP-1 cells with 27OHChol caused translocation of p65 NF-κB subunit into the nucleus and up-regulation of CD88. Inhibition of NF-κB and CD88 using SN50 and W-54011, respectively, resulted in reduced transcription of the IL-8 gene and attenuated secretion of CXCL8 induced by 27OHChol. We propose that oxidatively modified cholesterol like 27OHChol, rather than cholesterol, is responsible for sustained expression of CXCL8 in monocytes/macrophages in atherosclerotic arteries. - Highlights: • Consumption of a high-cholesterol diet leads to increased CXCL8 expression in ApoE{sup −/−} mice. • 27OHChol, but not cholesterol, up-regulates expression of CXCL8 in macrophages. • 27OHChol enhances nuclear translocation of NF-κB and expression of CD88 in macrophages. • Inhibition of NF-κB or CD88 results in decreased CXCL8 expression induced by 27OHChol. • 27OHChol up-regulates CXCL8 expression via NF-κB and CD88 in macrophages.

  10. The Measurement of High-Density Lipoprotein Mediated Cholesterol Efflux from Macrophage Cells by Liquid Chromatography Tandem Mass Spectrometry

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    Mo Wang

    2014-11-01

    Full Text Available Background: Studies have shown a negative association between macrophage cholesterol efflux and atherosclerotic cardiovascular diseases (CVD. However, the current methods for measuring cholesterol efflux require a radioactive tracer and involve a variety of cell treatments, making the measurement of macrophage cholesterol efflux impractical for use in clinical laboratories. In this study, we developed a non-radioactive and precise LC/MS/MS method for the measurement of high-density lipoprotein (HDL mediated cholesterol efflux from J774 macrophages. Methods: J774 cells were seeded on 12-well plates at a density of 1.5×105 cells/ml in H-DMEM medium, and when the cells were approximately 80% confluent, they were incubated with H-DMEM medium containing 2% FBS, 0.5 μg/ml ACAT inhibitor Sandoz 58-035, and 20 μg/ml [3,4-13C]cholesterol for 6 h. After washing and equilibrating the cells, HDL samples were added at a final concentration of 7% and incubated for 8 h. The cells were lysed, and [3,4-13C]cholesterol and cholesterol were measured by LC/MS/MS. Cholesterol efflux was expressed as the percent decrease of cell [3,4-13C]cholesterol mass during the incubation. Results: When incubated with [3,4-13C]cholesterol enriched J774 cells, HDL mediated higher cell cholesterol efflux than influx compared to serum and isolated LDL; therefore, HDL was used as the extracellular acceptor. The results from healthy volunteers showed that the rate of cholesterol efflux was negatively correlated with weight, BMI, blood pressure, and FERHDL and positively correlated with HDL-C, HDL2-C, and apoAI levels. Conclusions: A LC/MS/MS method for the measurement of HDL mediated cholesterol efflux from macrophage cells has been established. This method is non-radioactive, precise and reliable and is potentially useful for the assessment of HDL function and cardiovascular disease risks.

  11. Convergent Signaling Pathways Controlled by LRP1 (Receptor-related Protein 1) Cytoplasmic and Extracellular Domains Limit Cellular Cholesterol Accumulation.

    Science.gov (United States)

    El Asmar, Zeina; Terrand, Jérome; Jenty, Marion; Host, Lionel; Mlih, Mohamed; Zerr, Aurélie; Justiniano, Hélène; Matz, Rachel L; Boudier, Christian; Scholler, Estelle; Garnier, Jean-Marie; Bertaccini, Diego; Thiersé, Danièle; Schaeffer, Christine; Van Dorsselaer, Alain; Herz, Joachim; Bruban, Véronique; Boucher, Philippe

    2016-03-04

    The low density lipoprotein receptor-related protein 1 (LRP1) is a ubiquitously expressed cell surface receptor that protects from intracellular cholesterol accumulation. However, the underlying mechanisms are unknown. Here we show that the extracellular (α) chain of LRP1 mediates TGFβ-induced enhancement of Wnt5a, which limits intracellular cholesterol accumulation by inhibiting cholesterol biosynthesis and by promoting cholesterol export. Moreover, we demonstrate that the cytoplasmic (β) chain of LRP1 suffices to limit cholesterol accumulation in LRP1(-/-) cells. Through binding of Erk2 to the second of its carboxyl-terminal NPXY motifs, LRP1 β-chain positively regulates the expression of ATP binding cassette transporter A1 (ABCA1) and of neutral cholesterol ester hydrolase (NCEH1). These results highlight the unexpected functions of LRP1 and the canonical Wnt5a pathway and new therapeutic potential in cholesterol-associated disorders including cardiovascular diseases.

  12. THP-1 macrophage lipid accumulation unaffected by fatty acid double bond geometric or positional configuration

    Science.gov (United States)

    Dietary fatty acid type alters atherosclerotic lesion progression and macrophage lipid accumulation. Incompletely elucidated are the mechanisms by which fatty acids differing in double-bond geometric or positional configuration alter arterial lipid accumulation. The objective of this study was to ev...

  13. Oncocytic pleomorphic adenoma of palatal salivary gland with macrophages and giant cells associated with cholesterol crystals

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    Gargi S. Sarode

    2016-10-01

    Full Text Available Pleomorphic adenoma (PA is the most common salivary gland tumor characterized by histo-morphological diversity in the form of myxoid, hyalinized, chondroid, osseous, and squamous areas. In this paper, we report a rare case of predominantly oncocytic variant of PA in a 45-year-old male patient on the posterior palatal region. Microscopic examination showed homogenous eosinophilic cellular mass composed of epithelial components arranged in the form of tubular and solid patterns. The polygonal and oval cells showed abundant dark eosinophilic granular cytoplasm. The cell borders were distinct with a central nucleus showing prominent nucleoli. Interestingly at few places, cholesterol clefts were seen surrounded by macrophages and giant cells. The tumor was surgically excised with no evidence of recurrence after 2 years.

  14. The Bacillus anthracis cholesterol-dependent cytolysin, Anthrolysin O, kills human neutrophils, monocytes and macrophages

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    Rest Richard F

    2006-06-01

    Full Text Available Abstract Background Bacillus anthracis is an animal and human pathogen whose virulence is characterized by lethal and edema toxin, as well as a poly-glutamic acid capsule. In addition to these well characterized toxins, B. anthracis secretes several proteases and phospholipases, and a newly described toxin of the cholesterol-dependent cytolysin (CDC family, Anthrolysin O (ALO. Results In the present studies we show that recombinant ALO (rALO or native ALO, secreted by viable B. anthracis, is lethal to human primary polymorphonuclear leukocytes (PMNs, monocytes, monocyte-derived macrophages (MDMs, lymphocytes, THP-1 monocytic human cell line and ME-180, Detroit 562, and A549 epithelial cells by trypan blue exclusion or lactate dehydrogenase (LDH release viability assays. ALO cytotoxicity is dose and time dependent and susceptibility to ALO-mediated lysis differs between cell types. In addition, the viability of monocytes and hMDMs was assayed in the presence of vegetative Sterne strains 7702 (ALO+, UT231 (ALO-, and a complemented strain expressing ALO, UT231 (pUTE544, and was dependent upon the expression of ALO. Cytotoxicity of rALO is seen as low as 0.070 nM in the absence of serum. All direct cytotoxic activity is inhibited by the addition of cholesterol or serum concentration as low as 10%. Conclusion The lethality of rALO and native ALO on human monocytes, neutrophils, macrophages and lymphocytes supports the idea that ALO may represent a previously unidentified virulence factor of B. anthracis. The study of other factors produced by B. anthracis, along with the major anthrax toxins, will lead to a better understanding of this bacterium's pathogenesis, as well as provide information for the development of antitoxin vaccines for treating and preventing anthrax.

  15. miRNA-133a attenuates lipid accumulation via TR4-CD36 pathway in macrophages.

    Science.gov (United States)

    Peng, Xiao-Ping; Huang, Lei; Liu, Zhi-Hong

    2016-08-01

    lipid metabolism is the major causes of atherosclerosis. There is increasing evidence that miR-133a plays an important role in atherosclerosis. However, the regulatory mechanism of miR-133a in macrophages is still unclear. Several lines of evidence indicate that loss of TR4 leads to reduce lipid accumulation in liver and adipose tissues, etc, and lesional macrophages-derived TR4 can greatly increase the foam cell formation through increasing the CD36-mediated the uptake of ox-LDL. Interestingly, computational analysis suggests that TR4 may be a target gene of miR-133a. Here, we examined whether miR-133a regulates TR4 expression in ox-LDL-induced mouse RAW 264.7 macrophages, thereby affecting lipid accumulation. Using ox-LDL-treatment RAW 264.7 macrophages transfected with miR-133a mimics or inhibitors, we have showed that miR-133a can directly regulate the expression of TR4 in RAW 264.7 cells, thereby attenuates CD36-medide lipid accumulation. Furthermore, our studies suggest an additional explanation for the regulatory mechanism of miR-133a regulation to its functional target, TR4 in RAW 264.7 macrophages. Thus, our findings suggest that miR-133a may regulate lipid accumulation in ox-LDL-stimulated RAW 264.7 macrophages via TR4-CD36 pathway.

  16. Effects of Porphyromonas gingivalis lipopolysaccharide on the expression of key genes involved in cholesterol metabolism in macrophages

    Science.gov (United States)

    Liu, Fen; Wang, Yi; Xu, Jing; Liu, Fangqiang

    2016-01-01

    Introduction Cardiovascular diseases are positively correlated with periodontal disease. However, the molecular mechanisms linking atherosclerosis and periodontal infection are not clear. This study aimed to determine whether Porphyromonas gingivalis lipopolysaccharide (Pg-LPS) altered the expression of genes regulating cholesterol metabolism in macrophages in the presence of low-density lipoprotein (LDL). Material and methods THP-1-derived macrophages were exposed to different concentrations (0.1, 1, 10 µg/ml) of LPS in the presence of 50 µg/ml native LDL. Macrophages were also incubated with 1 µg/ml LPS for varying times (0, 24, 48, or 72 h) in the presence of native LDL. Foam cell formation was determined by oil red O staining and cholesterol content quantification. CD36, lectin-like oxidized LDL receptor-1 (LOX-1), ATP-binding cassette G1 (ABCG1), and acetyl CoA acyltransferase 1 (ACAT1) expression levels were measured by western blot and qRT-PCR. Results Foam cell formation was induced in a time- and concentration-dependent manner as assessed by both morphological and biochemical criteria. Pg-LPS caused downregulation of CD36 and ABCG1 but upregulation of ACAT1, while LOX-1 expression was not affected (p = 0.137). Conclusions Pg-LPS appears to be an important link in the development of atherosclerosis by mechanisms targeting cholesterol homeostasis, namely, excess cholesterol ester formation via ACAT1 and reduced cellular cholesterol efflux via ABCG1. PMID:27695485

  17. Macrophage Specific Caspase-1/11 Deficiency Protects against Cholesterol Crystallization and Hepatic Inflammation in Hyperlipidemic Mice

    NARCIS (Netherlands)

    Hendrikx, T.; Bieghs, V.; Walenbergh, S.M.; Gorp, P.J.J.; Verheyen, F.; Jeurissen, M.L.; Steinbusch, M.M.; Vaes, N.; Binder, C.J.; Koek, G.H.; Stienstra, R.; Netea, M.G.; Hofker, M.H.; Shiri-Sverdlov, R.

    2013-01-01

    BACKGROUND & AIMS: While non-alcoholic steatohepatitis (NASH) is characterized by hepatic steatosis combined with inflammation, the mechanisms triggering hepatic inflammation are unknown. In Ldlr(-/-) mice, we have previously shown that lysosomal cholesterol accumulation in Kupffer cells (KCs) corre

  18. Macrophage Specific Caspase-1/11 Deficiency Protects against Cholesterol Crystallization and Hepatic Inflammation in Hyperlipidemic Mice

    NARCIS (Netherlands)

    Hendrikx, T.; Bieghs, V.; Walenbergh, S.M.A.; Gorp, van P.J.; Verheyen, F.; Jeurissen, M.L.J.; Steinbusch, M.M.F.; Vaes, N.; Binder, C.J.; Koek, G.H.; Stienstra, R.; Netea, M.G.; Hofker, M.H.; Shiri-Sverdlov, R.

    2013-01-01

    Background & Aims: While non-alcoholic steatohepatitis (NASH) is characterized by hepatic steatosis combined with inflammation, the mechanisms triggering hepatic inflammation are unknown. In Ldlr(-/-) mice, we have previously shown that lysosomal cholesterol accumulation in Kupffer cells (KCs) c

  19. Macrophage Specific Caspase-1/11 Deficiency Protects against Cholesterol Crystallization and Hepatic Inflammation in Hyperlipidemic Mice

    NARCIS (Netherlands)

    Hendrikx, Tim; Bieghs, Veerle; Walenbergh, Sofie M. A.; van Gorp, Patrick J.; Verheyen, Fons; Jeurissen, Mike L. J.; Steinbusch, Mandy M. F.; Vaes, Nathalie; Binder, Christoph J.; Koek, Ger H.; Stienstra, Rinke; Netea, Mihai G.; Hofker, Marten H.; Shiri-Sverdlov, Ronit

    2013-01-01

    Background & Aims: While non-alcoholic steatohepatitis (NASH) is characterized by hepatic steatosis combined with inflammation, the mechanisms triggering hepatic inflammation are unknown. In Ldlr(-/-) mice, we have previously shown that lysosomal cholesterol accumulation in Kupffer cells (KCs) corre

  20. Hepatic accumulation of intestinal cholesterol is decreased and fecal cholesterol excretion is increased in mice fed a high-fat diet supplemented with milk phospholipids

    Directory of Open Access Journals (Sweden)

    Weir Jacquelyn M

    2010-12-01

    Full Text Available Abstract Background Milk phospholipids (PLs reduce liver lipid levels when given as a dietary supplement to mice fed a high-fat diet. We have speculated that this might be due to reduced intestinal cholesterol uptake. Methods Mice were given a high-fat diet for 3 or 5 weeks that had no added PL or that were supplemented with 1.2% by wt PL from cow's milk. Two milk PL preparations were investigated: a a PL-rich dairy milk extract (PLRDME, and b a commercially-available milk PL concentrate (PC-700. Intestinal cholesterol uptake was assessed by measuring fecal and hepatic radioactivity after intragastric administration of [14C]cholesterol and [3H]sitostanol. Fecal and hepatic lipids were measured enzymatically and by ESI-MS/MS. Results Both PL preparations led to significant decreases in total liver cholesterol and triglyceride (-20% to -60%, P 14C]cholesterol was significantly less (-30% to -60%, P 14C]cholesterol and unlabeled cholesterol was significantly higher in PL-supplemented mice (+15% to +30%, P 14C]cholesterol (P 14C]cholesterol (P P P Conclusion These results indicate that milk PL extracts reduce hepatic accumulation of intestinal cholesterol and increase fecal cholesterol excretion when given to mice fed a high-fat diet.

  1. EEPD1 Is a Novel LXR Target Gene in Macrophages Which Regulates ABCA1 Abundance and Cholesterol Efflux

    Science.gov (United States)

    Nelson, Jessica Kristine; Koenis, Duco Steven; Scheij, Saskia; Cook, Emma Clare Laura; Moeton, Martina; Santos, Ana; Lobaccaro, Jean-Marc Adolphe; Baron, Silvere

    2017-01-01

    Objective— The sterol-responsive nuclear receptors, liver X receptors α (LXRα, NR1H3) and β (LXRβ, NR1H2), are key determinants of cellular cholesterol homeostasis. LXRs are activated under conditions of high cellular sterol load and induce expression of the cholesterol efflux transporters ABCA1 and ABCG1 to promote efflux of excess cellular cholesterol. However, the full set of genes that contribute to LXR-stimulated cholesterol efflux is unknown, and their identification is the objective of this study. Approach and Results— We systematically compared the global transcriptional response of macrophages to distinct classes of LXR ligands. This allowed us to identify both common and ligand-specific transcriptional responses in macrophages. Among these, we identified endonuclease–exonuclease–phosphatase family domain containing 1 (EEPD1/KIAA1706) as a direct transcriptional target of LXRs in human and murine macrophages. EEPD1 specifically localizes to the plasma membrane owing to the presence of a myristoylation site in its N terminus. Accordingly, the first 10 amino acids of EEPD1 are sufficient to confer plasma membrane localization in the context of a chimeric protein with GFP. Functionally, we report that silencing expression of EEPD1 blunts maximal LXR-stimulated Apo AI-dependent efflux and demonstrate that this is the result of reduced abundance of ABCA1 protein in human and murine macrophages. Conclusions— In this study, we identify EEPD1 as a novel LXR-regulated gene in macrophages and propose that it promotes cellular cholesterol efflux by controlling cellular levels and activity of ABCA1. PMID:28082258

  2. EEPD1 Is a Novel LXR Target Gene in Macrophages Which Regulates ABCA1 Abundance and Cholesterol Efflux.

    Science.gov (United States)

    Nelson, Jessica Kristine; Koenis, Duco Steven; Scheij, Saskia; Cook, Emma Clare Laura; Moeton, Martina; Santos, Ana; Lobaccaro, Jean-Marc Adolphe; Baron, Silvere; Zelcer, Noam

    2017-03-01

    The sterol-responsive nuclear receptors, liver X receptors α (LXRα, NR1H3) and β (LXRβ, NR1H2), are key determinants of cellular cholesterol homeostasis. LXRs are activated under conditions of high cellular sterol load and induce expression of the cholesterol efflux transporters ABCA1 and ABCG1 to promote efflux of excess cellular cholesterol. However, the full set of genes that contribute to LXR-stimulated cholesterol efflux is unknown, and their identification is the objective of this study. We systematically compared the global transcriptional response of macrophages to distinct classes of LXR ligands. This allowed us to identify both common and ligand-specific transcriptional responses in macrophages. Among these, we identified endonuclease-exonuclease-phosphatase family domain containing 1 (EEPD1/KIAA1706) as a direct transcriptional target of LXRs in human and murine macrophages. EEPD1 specifically localizes to the plasma membrane owing to the presence of a myristoylation site in its N terminus. Accordingly, the first 10 amino acids of EEPD1 are sufficient to confer plasma membrane localization in the context of a chimeric protein with GFP. Functionally, we report that silencing expression of EEPD1 blunts maximal LXR-stimulated Apo AI-dependent efflux and demonstrate that this is the result of reduced abundance of ABCA1 protein in human and murine macrophages. In this study, we identify EEPD1 as a novel LXR-regulated gene in macrophages and propose that it promotes cellular cholesterol efflux by controlling cellular levels and activity of ABCA1. © 2017 The Authors.

  3. Skeletal muscle insulin resistance associated with cholesterol-induced activation of macrophages is prevented by high density lipoprotein.

    Directory of Open Access Journals (Sweden)

    Andrew L Carey

    Full Text Available BACKGROUND: Emerging evidence suggests that high density lipoprotein (HDL may modulate glucose metabolism through multiple mechanisms including pancreatic insulin secretion as well as insulin-independent glucose uptake into muscle. We hypothesized that HDL may also increase skeletal muscle insulin sensitivity via cholesterol removal and anti-inflammatory actions in macrophages associated with excess adiposity and ectopic lipid deposition. METHODS: Human primary and THP-1 macrophages were treated with vehicle (PBS or acetylated low density lipoprotein (acLDL with or without HDL for 18 hours. Treatments were then removed, and macrophages were incubated with fresh media for 4 hours. This conditioned media was then applied to primary human skeletal myotubes derived from vastus lateralis biopsies taken from patients with type 2 diabetes to examine insulin-stimulated glucose uptake. RESULTS: Conditioned media from acLDL-treated primary and THP-1 macrophages reduced insulin-stimulated glucose uptake in primary human skeletal myotubes compared with vehicle (primary macrophages, 168±21% of basal uptake to 104±19%; THP-1 macrophages, 142±8% of basal uptake to 108±6%; P<0.05. This was restored by co-treatment of macrophages with HDL. While acLDL increased total intracellular cholesterol content, phosphorylation of c-jun N-terminal kinase and secretion of pro- and anti-inflammatory cytokines from macrophages, none were altered by co-incubation with HDL. Insulin-stimulated Akt phosphorylation in human skeletal myotubes exposed to conditioned media was unaltered by either treatment condition. CONCLUSION: Inhibition of insulin-stimulated glucose uptake in primary human skeletal myotubes by conditioned media from macrophages pre-incubated with acLDL was restored by co-treatment with HDL. However, these actions were not linked to modulation of common pro- or anti-inflammatory mediators or insulin signaling via Akt.

  4. Distinctive role of activated tumor-associated macrophages in photosensitizer accumulation

    Science.gov (United States)

    Korbelik, Mladen; Krosl, Gorazd

    1995-05-01

    Cells dissociated from tumors (carcinomas and sarcomas) growing subcutaneously in mice that have been administered Photofrin or other photosensitizers were analyzed by flow cytometry. Monoclonal antibodies were used for identification of major cellular populations contained in these tumors. The results demonstrate that a subpopulation of tumor-associated macrophages (TAMs) is unique among tumor cell populations in that it excels in the accumulation of very high levels of photosensitizers. These macrophages showed an increased expression of interleukin 2 receptor, which is indicative of their activated state. since macrophages were reported to concentrate in the periphery of human neoplasms, it is suggested that activates TAMs are the determinants of tumor-localized photosensitizer fluorescence.

  5. Mitochondrial cholesterol accumulation in alcoholic liver disease: Role of ASMase and endoplasmic reticulum stress.

    Science.gov (United States)

    Marí, Montserrat; Morales, Albert; Colell, Anna; García-Ruiz, Carmen; Fernández-Checa, Jose C

    2014-01-01

    Alcoholic liver disease (ALD) is a major cause of chronic liver disease and a growing health concern in theworld. While the pathogenesis of ALD is poorly characterized key players identified in experimental models and patients, such as perturbations in mitochondrial structure and function, selective loss of antioxidant defense and susceptibility to inflammatory cytokines, contribute to ALD progression. Both oxidative stress and mitochondrial dysfunction compromise essential cellular functions and energy generation and hence are important pathogenic mechanisms of ALD. An important process mediating the mitochondrial disruption induced by alcohol intake is the trafficking of cholesterol to mitochondria, mediated by acid sphingomyelinase-induced endoplasmic reticulum stress, which contributes to increased cholesterol synthesis and StARD1upregulation. Mitochondrial cholesterol accumulation not only sensitizes to oxidative stress but it can contribute to the metabolic reprogramming in ALD, manifested by activation of the hypoxia inducible transcription factor 1 and stimulation of glycolysis and lactate secretion. Thus, a better understanding of the mechanisms underlying alcohol-mediated mitochondrial impairment and oxidative stress may lead to the identification of novel treatments for ALD. The present review briefly summarizes current knowledge on the cellular and molecular mechanisms contributing to alcohol-induced mitochondrial dysfunction and cholesterol accumulation and provides insights for potential therapeutic targets in ALD.

  6. African swine fever virus infects macrophages, the natural host cells, via clathrin- and cholesterol-dependent endocytosis.

    Science.gov (United States)

    Galindo, Inmaculada; Cuesta-Geijo, Miguel Angel; Hlavova, Karolina; Muñoz-Moreno, Raquel; Barrado-Gil, Lucía; Dominguez, Javier; Alonso, Covadonga

    2015-03-16

    The main cellular target for African swine fever virus (ASFV) is the porcine macrophage. However, existing data about the early phases of infection were previously characterized in non-leukocyte cells such as Vero cells. Here, we report that ASFV enters the natural host cell using dynamin-dependent and clathrin-mediated endocytosis. This pathway is strongly pH-dependent during the first steps of infection in porcine macrophages. We investigated the effect of drugs inhibiting several endocytic pathways in macrophages and compared ASFV with vaccinia virus (VV), which apparently involves different entry pathways. The presence of cholesterol in cellular membranes was found to be essential for a productive ASFV infection while actin-dependent endocytosis and the participation of phosphoinositide-3-kinase (PI3K) activity were other cellular factors required in the process of viral entry. These findings improved our understanding of the ASFV interactions with macrophages that allow for successful viral replication.

  7. Arachidonic acid accumulates in the stromal macrophages during thymus involution in diabetes.

    Science.gov (United States)

    Gruia, Alexandra T; Barbu-Tudoran, Lucian; Mic, Ani A; Ordodi, Valentin L; Paunescu, Virgil; Mic, Felix A

    2011-07-01

    Diabetes is a debilitating disease with chronic evolution that affects many tissues and organs over its course. Thymus is an organ that is affected early after the onset of diabetes, gradually involuting until it loses most of its thymocyte populations. We show evidence of accumulating free fatty acids with generation of eicosanoids in the diabetic thymus and we present a possible mechanism for the involution of the organ during the disease. Young rats were injected with streptozotocin and their thymuses examined for cell death by flow cytometry and TUNEL reaction. Accumulation of lipids in the diabetic thymus was investigated by histology and electron microscopy. The identity and quantitation of accumulating lipids was done with gas chromatography-mass spectrometry and liquid chromatography. The expression and dynamics of the enzymes were monitored via immunohistochemistry. Diabetes causes thymus involution by elevating the thymocyte apoptosis. Exposure of thymocytes to elevated concentration of glucose causes apoptosis. After the onset of diabetes, there is a gradual accumulation of free fatty acids in the stromal macrophages including arachidonic acid, the substrate for eicosanoids. The eicosanoids do not cause thymocyte apoptosis but administration of a cyclooxygenase inhibitor reduces the staining for ED1, a macrophage marker whose intensity correlates with phagocytic activity. Diabetes causes thymus involution that is accompanied by accumulation of free fatty acids in the thymic macrophages. Excess glucose is able to induce thymocyte apoptosis but eicosanoids are involved in the chemoattraction of macrophage to remove the dead thymocytes.

  8. Myeloid Acyl-CoA:Cholesterol Acyltransferase 1 Deficiency Reduces Lesion Macrophage Content and Suppresses Atherosclerosis Progression.

    Science.gov (United States)

    Huang, Li-Hao; Melton, Elaina M; Li, Haibo; Sohn, Paul; Rogers, Maximillian A; Mulligan-Kehoe, Mary Jo; Fiering, Steven N; Hickey, William F; Chang, Catherine C Y; Chang, Ta-Yuan

    2016-03-18

    Acyl-CoA:cholesterol acyltransferase 1 (Acat1) converts cellular cholesterol to cholesteryl esters and is considered a drug target for treating atherosclerosis. However, in mouse models for atherosclerosis, global Acat1 knockout (Acat1(-/-)) did not prevent lesion development. Acat1(-/-) increased apoptosis within lesions and led to several additional undesirable phenotypes, including hair loss, dry eye, leukocytosis, xanthomatosis, and a reduced life span. To determine the roles of Acat1 in monocytes/macrophages in atherosclerosis, we produced a myeloid-specific Acat1 knockout (Acat1(-M/-M)) mouse and showed that, in the Apoe knockout (Apoe(-/-)) mouse model for atherosclerosis, Acat1(-M/-M) decreased the plaque area and reduced lesion size without causing leukocytosis, dry eye, hair loss, or a reduced life span. Acat1(-M/-M) enhanced xanthomatosis in apoe(-/-) mice, a skin disease that is not associated with diet-induced atherosclerosis in humans. Analyses of atherosclerotic lesions showed that Acat1(-M/-M) reduced macrophage numbers and diminished the cholesterol and cholesteryl ester load without causing detectable apoptotic cell death. Leukocyte migration analysis in vivo showed that Acat1(-M/-M) caused much fewer leukocytes to appear at the activated endothelium. Studies in inflammatory (Ly6C(hi)-positive) monocytes and in cultured macrophages showed that inhibiting ACAT1 by gene knockout or by pharmacological inhibition caused a significant decrease in integrin β 1 (CD29) expression in activated monocytes/macrophages. The sparse presence of lesion macrophages without Acat1 can therefore, in part, be attributed to decreased interaction between inflammatory monocytes/macrophages lacking Acat1 and the activated endothelium. We conclude that targeting ACAT1 in a myeloid cell lineage suppresses atherosclerosis progression while avoiding many of the undesirable side effects caused by global Acat1 inhibition.

  9. Myeloid Acyl-CoA:Cholesterol Acyltransferase 1 Deficiency Reduces Lesion Macrophage Content and Suppresses Atherosclerosis Progression*

    Science.gov (United States)

    Huang, Li-Hao; Melton, Elaina M.; Li, Haibo; Sohn, Paul; Rogers, Maximillian A.; Mulligan-Kehoe, Mary Jo; Fiering, Steven N.; Hickey, William F.; Chang, Catherine C. Y.; Chang, Ta-Yuan

    2016-01-01

    Acyl-CoA:cholesterol acyltransferase 1 (Acat1) converts cellular cholesterol to cholesteryl esters and is considered a drug target for treating atherosclerosis. However, in mouse models for atherosclerosis, global Acat1 knockout (Acat1−/−) did not prevent lesion development. Acat1−/− increased apoptosis within lesions and led to several additional undesirable phenotypes, including hair loss, dry eye, leukocytosis, xanthomatosis, and a reduced life span. To determine the roles of Acat1 in monocytes/macrophages in atherosclerosis, we produced a myeloid-specific Acat1 knockout (Acat1−M/−M) mouse and showed that, in the Apoe knockout (Apoe−/−) mouse model for atherosclerosis, Acat1−M/−M decreased the plaque area and reduced lesion size without causing leukocytosis, dry eye, hair loss, or a reduced life span. Acat1−M/−M enhanced xanthomatosis in apoe−/− mice, a skin disease that is not associated with diet-induced atherosclerosis in humans. Analyses of atherosclerotic lesions showed that Acat1−M/−M reduced macrophage numbers and diminished the cholesterol and cholesteryl ester load without causing detectable apoptotic cell death. Leukocyte migration analysis in vivo showed that Acat1−M/−M caused much fewer leukocytes to appear at the activated endothelium. Studies in inflammatory (Ly6Chi-positive) monocytes and in cultured macrophages showed that inhibiting ACAT1 by gene knockout or by pharmacological inhibition caused a significant decrease in integrin β 1 (CD29) expression in activated monocytes/macrophages. The sparse presence of lesion macrophages without Acat1 can therefore, in part, be attributed to decreased interaction between inflammatory monocytes/macrophages lacking Acat1 and the activated endothelium. We conclude that targeting ACAT1 in a myeloid cell lineage suppresses atherosclerosis progression while avoiding many of the undesirable side effects caused by global Acat1 inhibition. PMID:26801614

  10. Ethanolic extracts of Brazilian red propolis increase ABCA1 expression and promote cholesterol efflux from THP-1 macrophages.

    Science.gov (United States)

    Iio, Akio; Ohguchi, Kenji; Maruyama, Hiroe; Tazawa, Shigemi; Araki, Yoko; Ichihara, Kenji; Nozawa, Yoshinori; Ito, Masafumi

    2012-03-15

    The ATP-binding cassette transporter A1 (ABCA1) is a membrane transporter that directly contributes to high-density lipoprotein (HDL) biogenesis by regulating the cellular efflux of cholesterol. Since ABCA1 plays a pivotal role in cholesterol homeostasis and HDL metabolism, identification of a novel substance that is capable of increasing its expression would be beneficial for the prevention and therapy of atherosclerosis. In the present study, we studied the effects of ethanolic extracts of Brazilian red propolis (EERP) on ABCA1 expression and cholesterol efflux in THP-1 macrophages. EERP enhanced PPARγ and liver X receptor (LXR) transcriptional activity at 5-15μg/ml, which was associated with upregulation of PPARγ and LXRα expression. It was also found that EERP increase the activity of the ABCA1 promoter, which is positively regulated by LXR. Consistent with these findings, treatment with EERP increased both mRNA and protein expression of ABCA1. Finally, EERP upregulated ApoA-I-mediated cholesterol efflux. Our results showed that EERP promote ApoA-I-mediated cholesterol efflux from macrophages by increasing ABCA1 expression via induction of PPARγ/LXR. Copyright © 2011 Elsevier GmbH. All rights reserved.

  11. Impaired phagocytosis of apoptotic cells causes accumulation of bone marrow-derived macrophages in aged mice

    Science.gov (United States)

    Kim, Ok-Hee; Kim, Hyojung; Kang, Jinku; Yang, Dongki; Kang, Yu-Hoi; Lee, Dae Ho; Cheon, Gi Jeong; Park, Sang Chul; Oh, Byung-Chul

    2017-01-01

    Accumulation of tissue macrophages is a significant characteristic of disease-associated chronic inflammation, and facilitates the progression of disease pathology. However, the functional roles of these bone marrow-derived macrophages (BMDMs) in aging are unclear. Here, we identified age-dependent macrophage accumulation in the bone marrow, showing that aging significantly increases the number of M1 macrophages and impairs polarization of BMDMs. We found that age-related dysregulation of BMDMs is associated with abnormal overexpression of the anti-inflammatory interleukin-10. BMDM dysregulation in aging impairs the expression levels of pro-inflammatory cytokines and genes involved in B-cell maturation and activation. Phagocytosis of apoptotic Jurkat cells by BMDMs was reduced because of low expression of phagocytic receptor CD14, indicating that increased apoptotic cells may result from defective phagocytosis of apoptotic cells in the BM of aged mice. Therefore, CD14 may represent a promising target for preventing BMDM dysregulation, and macrophage accumulation may provide diagnostic and therapeutic clues. PMID:27866511

  12. Alpha-linolenic acid increases cholesterol efflux in macrophage-derived foam cells by decreasing stearoyl CoA desaturase 1 expression: evidence for a farnesoid-X-receptor mechanism of action.

    Science.gov (United States)

    Zhang, Jun; Kris-Etherton, Penny M; Thompson, Jerry T; Hannon, Daniel B; Gillies, Peter J; Heuvel, John P Vanden

    2012-04-01

    Increased cholesterol efflux from macrophage-derived foam cells (MDFCs) is an important protective mechanism to decrease lipid load in the atherosclerotic plaque. Dietary alpha-linolenic acid (ALA), an omega-3 polyunsaturated fatty acid (PUFA), decreases circulating cholesterol, but its role in cholesterol efflux has not been extensively studied. Stearoyl CoA desaturase 1 (SCD1) is the rate-limiting enzyme in the synthesis of monounsaturated fatty acids (MUFAs). Endogenous MUFAs are preferentially incorporated into triglycerides, phospholipids and cholesteryl ester, which are abundant in atherosclerotic plaque. This study investigated the mechanisms by which ALA regulated SCD1 and subsequent effect on cholesterol storage and transport in MDFCs. Small interfering RNA (siRNA) also was applied to modify SCD1 expression in foam cells. Alpha-linolenic acid treatment and SCD1 siRNA significantly decreased SCD1 expression in MDFCs. The reduction of SCD1 was accompanied with increased cholesterol efflux and decreased intracellular cholesterol storage within these cells. Alpha-linolenic acid activated the nuclear receptor farnesoid-X-receptor, which in turn increased its target gene small heterodimer partner (SHP) expression, and decreased liver-X-receptor dependent sterol regulatory element binding protein 1c transcription, ultimately resulting in repressed SCD1 expression. In conclusion, repression of SCD1 by ALA favorably increased cholesterol efflux and decreased cholesterol accumulation in foam cells. This may be one mechanism by which dietary omega-3 PUFAs promote atherosclerosis regression. Copyright © 2012 Elsevier Inc. All rights reserved.

  13. Sesamol and sesame (Sesamum indicum) oil enhance macrophage cholesterol efflux via up-regulation of PPARγ1 and LXRα transcriptional activity in a MAPK-dependent manner.

    Science.gov (United States)

    Majdalawieh, Amin F; Ro, Hyo-Sung

    2015-08-01

    Cholesterol clearance by macrophages is a vital process to eliminate excess cholesterol from the body. Internalization of modified cholesterol by macrophages triggers overexpression of peroxisome proliferator-activated receptor γ1 (PPARγ1) and liver X receptor α (LXRα), two transcription factors that are critically involved in macrophage cholesterol efflux. Recent studies demonstrate that oral administration of sesamol derivative (INV-403) and sesame oil leads to a significant attenuation of atherosclerosis in Watanabe heritable hyperlipidemic rabbits and LDLR(-/-) mice, respectively. However, the exact molecular mechanisms underlying such anti-atherogenic effects remain largely unrevealed. Luciferase reporter assays were performed to assess the effects of sesamol and sesame oil on PPARγ1 and LXRα gene expression. The potential of sesamol and sesame oil to modulate cholesterol efflux was evaluated using (3)H-cholesterol efflux assays. Sesamol and sesame oil treatments lead to a significant up-regulation of PPARγ1 and LXRα expression and transcriptional activity in a MAPK-dependent manner. Importantly, primary macrophages display a significantly enhanced cholesterol efflux potential upon treatment with sesamol and sesame oil, and this stimulatory effect is mediated by MAPK signaling. Our findings suggest that the previously reported anti-atherogenic effects of sesamol and sesame oil could be attributed, at least in part, to enhanced PPARγ1 and LXRα expression and transcriptional activity leading to improved macrophage cholesterol efflux. Our study is novel in elucidating the molecular and cellular mechanisms underlying the protective effects of sesamol and sesame oil against atherosclerosis.

  14. Cholesterol Corrects Altered Conformation of MHC-II Protein in Leishmania donovani Infected Macrophages: Implication in Therapy.

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    Koushik Roy

    2016-05-01

    Full Text Available Previously we reported that Kala-azar patients show progressive decrease in serum cholesterol as a function of splenic parasite burden. Splenic macrophages (MΦ of Leishmania donovani (LD infected mice show decrease in membrane cholesterol, while LD infected macrophages (I-MΦ show defective T cell stimulating ability that could be corrected by liposomal delivery of cholesterol. T helper cells recognize peptide antigen in the context of class II MHC molecule. It is known that the conformation of a large number of membrane proteins is dependent on membrane cholesterol. In this investigation we tried to understand the influence of decreased membrane cholesterol in I-MΦ on the conformation of MHC-II protein and peptide-MHC-II stability, and its bearing on the antigen specific T-cell activation.MΦ of CBA/j mice were infected with Leishmania donovani (I-MΦ. Two different anti-Aκ mAbs were used to monitor the status of MHC-II protein under parasitized condition. One of them (11.5-2 was conformation specific, whereas the other one (10.2.16 was not. Under parasitized condition, the binding of 11.5-2 decreased significantly with respect to the normal counterpart, whereas that of 10.2.16 remained unaltered. The binding of 11.5-2 was restored to normal upon liposomal delivery of cholesterol in I-MΦ. By molecular dynamics (MD simulation studies we found that there was considerable conformational fluctuation in the transmembrane domain of the MHC-II protein in the presence of membrane cholesterol than in its absence, which possibly influenced the distal peptide binding groove. This was evident from the faster dissociation of the cognate peptide from peptide-MHC complex under parasitized condition, which could be corrected by liposomal delivery of cholesterol in I-MΦ.The decrease in membrane cholesterol in I-MΦ may lead to altered conformation of MHC II, and this may contribute to a faster dissociation of the peptide. Furthermore, liposomal delivery of

  15. Mitochondrial function is involved in regulation of cholesterol efflux to apolipoprotein (apoA-I from murine RAW 264.7 macrophages

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    Allen Anne Marie

    2012-12-01

    Full Text Available Abstract Background Mitochondrial DNA damage, increased production of reactive oxygen species and progressive respiratory chain dysfunction, together with increased deposition of cholesterol and cholesteryl esters, are hallmarks of atherosclerosis. This study investigated the role of mitochondrial function in regulation of macrophage cholesterol efflux to apolipoprotein A-I, by the addition of established pharmacological modulators of mitochondrial function. Methods Murine RAW 264.7 macrophages were treated with a range of concentrations of resveratrol, antimycin, dinitrophenol, nigericin and oligomycin, and changes in viability, cytotoxicity, membrane potential and ATP, compared with efflux of [3H]cholesterol to apolipoprotein (apo A-I. The effect of oligomycin treatment on expression of genes implicated in macrophage cholesterol homeostasis were determined by quantitative polymerase chain reaction, and immunoblotting, relative to the housekeeping enzyme, Gapdh, and combined with studies of this molecule on cholesterol esterification, de novo lipid biosynthesis, and induction of apoptosis. Significant differences were determined using analysis of variance, and Dunnett’s or Bonferroni post t-tests, as appropriate. Results The positive control, resveratrol (24 h, significantly enhanced cholesterol efflux to apoA-I at concentrations ≥30 μM. By contrast, cholesterol efflux to apoA-I was significantly inhibited by nigericin (45%; ppAbca1 mRNA. Oligomycin treatment did not affect cholesterol biosynthesis, but significantly inhibited cholesterol esterification following exposure to acetylated LDL, and induced apoptosis at ≥30 μM. Finally, oligomycin induced the expression of genes implicated in both cholesterol efflux (Abca1, Abcg4, Stard1 and cholesterol biosynthesis (Hmgr, Mvk, Scap, Srebf2, indicating profound dysregulation of cholesterol homeostasis. Conclusions Acute loss of mitochondrial function, and in particular Δψm, reduces

  16. Interleukin-10 increases reverse cholesterol transport in macrophages through its bidirectional interaction with liver X receptor α

    Energy Technology Data Exchange (ETDEWEB)

    Halvorsen, Bente, E-mail: Bente.Halvorsen@rr-research.no [Research Institute of Internal Medicine, Oslo University Hospital Rikshospitalet, Oslo (Norway); Institute of Clinical Medicine, University of Oslo, Oslo (Norway); K.G. Jebsen Inflammation Research Center, University of Oslo, Oslo (Norway); Holm, Sverre [Research Institute of Internal Medicine, Oslo University Hospital Rikshospitalet, Oslo (Norway); Yndestad, Arne [Research Institute of Internal Medicine, Oslo University Hospital Rikshospitalet, Oslo (Norway); Institute of Clinical Medicine, University of Oslo, Oslo (Norway); K.G. Jebsen Inflammation Research Center, University of Oslo, Oslo (Norway); Scholz, Hanne [Section for Transplantation, Institute for Surgical Research, Oslo University Hospital Rikshospitalet, Oslo (Norway); Sagen, Ellen Lund [Research Institute of Internal Medicine, Oslo University Hospital Rikshospitalet, Oslo (Norway); Nebb, Hilde [Department of Nutrition, Institute for Basic Medical Sciences, University of Oslo, Oslo (Norway); Institute of Clinical Medicine, University of Oslo, Oslo (Norway); Holven, Kirsten B. [Department of Nutrition, Institute for Basic Medical Sciences, University of Oslo, Oslo (Norway); Dahl, Tuva B. [Research Institute of Internal Medicine, Oslo University Hospital Rikshospitalet, Oslo (Norway); Institute of Clinical Medicine, University of Oslo, Oslo (Norway); Aukrust, Pål [Research Institute of Internal Medicine, Oslo University Hospital Rikshospitalet, Oslo (Norway); Section of Clinical Immunology and Infectious Diseases, Oslo University Hospital Rikshospitalet, Oslo (Norway); Institute of Clinical Medicine, University of Oslo, Oslo (Norway); K.G. Jebsen Inflammation Research Center, University of Oslo, Oslo (Norway)

    2014-08-08

    Highlights: • IL-10 promotes reverse cholesterol efflux from lipid loaded macrophages. • IL-10 increases the expression of ABCA-1 and ABCG-1. • IL-10 exhibits cross-talk with the nuclear receptor LXRα. - Abstract: Interleukin (IL)-10 is a prototypical anti-inflammatory cytokine that has been shown to attenuate atherosclerosis development. In addition to its anti-inflammatory properties, the anti-atherogenic effect of IL-10 has recently also been suggested to reflect a complex effect of IL-10 on lipid metabolism in macrophages. In the present study we examined the effects of IL-10 on cholesterol efflux mechanism in lipid-loaded THP-1 macrophages. Our main findings were: (i) IL-10 significantly enhanced cholesterol efflux induced by fetal-calf serum, high-density lipoprotein (HDL){sub 2} and apolipoprotein A-1. (ii) The IL-10-mediated effects on cholesterol efflux were accompanied by an increased IL-10-mediated expression of the ATP-binding cassette transporters ABCA1 and ABCG1, that was further enhanced when the cells were co-activated with the liver X receptor (LXR)α agonist (22R)-hydroxycholesterol. (iii) The effect of LXRα activation on the IL-10-mediated effects on the ATP-binding cassette transporters seems to include enhancing effects on the IL-10 receptor 1 (IL10R1) expression and interaction with STAT-3 signaling. (iv) These enhancing effects on ABCA1 and ABCG1 was not seen when the cells were stimulated with the IL-10 family members IL-22 and IL-24. This study suggests that the anti-atherogenic properties of IL-10 may include enhancing effects on cholesterol efflux mechanism that involves cross-talk with LXRα activation.

  17. Cholesterol secoaldehyde induces apoptosis in J774 macrophages via mitochondrial pathway but not involving reactive oxygen species as mediators.

    Science.gov (United States)

    Gao, Xueli; Raghavamenon, Achuthan C; D'Auvergne, Oswald; Uppu, Rao M

    2009-11-13

    Cholesterol secoaldehyde (3beta-hydroxy-5-oxo-5,6-secocholestan-6-al or ChSeco) is an oxysterol known to be formed in reactions of ozone with cholesterol and also when cholesterol-5alpha-hydroperoxide undergoes Hock cleavage. In view of its widespread occurrence and atherogenic potential, we examined the effects of ChSeco on mouse J774 macrophage viability and events associated with apoptosis. A dose-dependent decrease in cell viability, disruptions in mitochondrial transmembrane potential (64+/-5.5%; mean+/-SD, n=3), increased levels of cytosolic cytochrome c (8.8+/-0.84 ng/ml; mean+/-SD, n=3), activation of caspase-3 (ca. 3.6-fold) and caspase-9 (ca.1.8-fold), and increased DNA fragmentation (ca. 5-fold), all indicative of apoptosis, were observed in response to exposure to ChSeco. The apoptotic nature of cell death in macrophages was confirmed by dual staining with acridine orange and ethidium bromide. However, unlike the case with cardiomyoblasts and neuronal cells, the apoptotic process in these immune cells was not mediated by increased levels of reactive oxygen species as indicated by a minimal or no increase in 2',7'-dichlorofluorescein fluorescence. It is suggested that the apoptotic process is mediated via the mitochondrial pathway and that ChSeco formed in biological environments contributes to the initiation, progression, and culmination of atherosclerotic plaque formation, as these processes are critically dependent on macrophage apoptosis.

  18. GABA and Topiramate Inhibit the Formation of Human Macrophage-Derived Foam Cells by Modulating Cholesterol-Metabolism-Associated Molecules

    Directory of Open Access Journals (Sweden)

    Ying Yang

    2014-04-01

    Full Text Available Aims: γ-aminobutyric acid (GABA, the principal inhibitory neurotransmitter, acts on GABA receptors to play an important role in the modulation of macrophage functions. The present study examined the effects of GABA and a GABA receptor agonist on modulating cholesterol-metabolism-associated molecules in human monocyte-derived macrophages (HMDMs. Methods: ORO stain, HPLC, qRT-PCR, Western blot and EMSA were carried out using HMDMs exposed to ox-LDL with or without GABAergic agents as the experimental model. Results: GABA and topiramate reduced the percentage of cholesterol ester in lipid-laden HMDMs by down-regulating SR-A, CD36 and LOX-1 expression and up-regulating ABCA1, ABCG1 and SR-BI expression in lipid-laden HMDMs. The production of TNF-a was decreased in GABA-and topiramate-treated lipid-laden HMDMs, and levels of interleukin (IL-6 did not change. The activation of two signaling pathways, p38MAPK and NF-γB, was repressed by GABA and topiramate in lipid-laden HMDMs. Conclusion: GABA and topiramate inhibit the formation of human macrophage-derived foam cells and may be a possibility for macrophage targeted therapy of atherosclerotic lesions.

  19. Marrubium vulgare extract inhibits human-LDL oxidation and enhances HDL-mediated cholesterol efflux in THP-1 macrophage.

    Science.gov (United States)

    Berrougui, Hicham; Isabelle, Maxim; Cherki, Mounia; Khalil, Abdelouahed

    2006-12-14

    The objective of the present study was to elucidate the beneficial properties of aqueous extracts of Marrubium vulgare (AEM) towards cardiovascular disease by protecting human-LDL against lipid peroxidation and promoting HDL-mediated cholesterol efflux. Human-LDL were oxidised by incubation with CuSO(4) in the presence of increased concentrations of AEM (0-100 microg/ml). LDL lipid peroxidation was evaluated by conjugated diene formation, vitamin E disappearance as well as LDL-electrophoretic mobility. HDL-mediated cholesterol efflux assay was carried out in human THP-1 macrophages. Incubation of LDL with AEM significantly prolonged the lag phase (P=0.014), lowered the progression rate of lipid peroxidation (P=0.004), reduced the disappearance of vitamin E and the electrophoretic mobility in a dose-dependent manner. Also, incubation of HDL with AEM significantly increased HDL-mediated cholesterol efflux from THP-1 macrophages implicating an independent ATP binding cassette A1 (ABCA1) pathways. Our findings suggest that M. vulgare provides a source of natural antioxidants, which inhibit LDL oxidation and enhance reverse cholesterol transport and thus can prevent cardiovascular diseases development. These antioxidant properties increase the anti-atherogenic potential of HDL.

  20. A matrix of cholesterol crystals, but not cholesterol alone, primes human monocytes/macrophages for excessive endotoxin-induced production of tumor necrosis factor-alpha. Role in atherosclerotic inflammation?

    DEFF Research Database (Denmark)

    Bendtzen, Klaus; Christensen, Ole; Nielsen, Claus Henrik

    2014-01-01

    When exposed to small amounts of bacterial endotoxin, matrices of cholesterol crystals, but not cholesterol itself, primed human monocytes/macrophages to a highly augmented (>10-fold) production of inflammatory tumor necrosis factor-α. Priming also sensitized the cells, as 10- to 100-fold lower...... suggest that cholesterol matrix formation may play a pathogenic role in atherosclerotic inflammation, and they indicate a mechanism by which bacteria and/or bacterial products may play a role in processes leading to arteriosclerosis....

  1. Correlation between the decrease of cholesterol efflux from macrophages in patients with type II diabetes mellitus and down-regulated CYP7A1 expression.

    Science.gov (United States)

    Bao, L D; Li, C Q; Peng, R; Ren, X H; Ma, R L; Wang, Y; Lv, H J

    2015-07-31

    The purpose of this study was to examine the changes of cellular cholesterol efflux from macrophages in patients with type II diabetes mellitus (DM), and to determine the expression of CYP7A1, ABCG5, and LXRβ therein. We recruited 30 patients with type II DM (including 15 patients complicated with coronary heart disease and 15 patients with DM only) and 15 normal controls for this study. Peripheral blood monocytes were isolated for macrophage culture. The mRNA and protein expression levels of CYP7A1, ABCG5, and LXRβ were determined using real-time polymerase chain reaction and western blot. The macrophage cholesterol efflux rate was determined with 10% autoserum and standard serum as receptors. We determined that the expression levels of macrophage CYP7A1 mRNA and protein in the type II DM group were significantly lower than those in the control group, but no differences were found in the ABCG5 and LXRβ expression levels between the groups. The macrophage cholesterol efflux rate in the patients with type II DM was also significantly decreased compared with that of the normal control subjects (P CYP7A1 mRNA expression and macrophage cholesterol efflux rate were significantly positively correlated. In summary, this study demonstrated that the macrophage cholesterol efflux in patients with type II DM was significantly reduced, and that this reduction was associated with the down-regulation of CYP7A1 expression.

  2. Understanding the accumulation of P-glycoprotein substrates within cells: The effect of cholesterol on membrane partitioning.

    Science.gov (United States)

    Subramanian, Nandhitha; Schumann-Gillett, Alexandra; Mark, Alan E; O'Mara, Megan L

    2016-04-01

    The apparent activity of the multidrug transporter P-glycoprotein (P-gp) is enhanced by the presence of cholesterol. Whether this is due to the direct effect of cholesterol on the activity of P-gp, its effect on the local concentration of substrate in the membrane, or its effect on the rate of entry of the drug into the cell, is unknown. In this study, molecular dynamics simulation techniques coupled with potential of mean force calculations have been used to investigate the role of cholesterol in the movement of four P-gp substrates across a POPC bilayer in the presence or absence of 10% cholesterol. The simulations suggest that the presence of cholesterol lowers the free energy associated with entering the middle of the bilayer in a substrate-specific manner. These findings suggest that P-gp substrates may preferentially accumulate in cholesterol-rich regions of the membrane, which may explain its enhanced transport activity.

  3. Role of macrophages in age-related oxidative stress and lipofuscin accumulation in mice.

    Science.gov (United States)

    Vida, Carmen; de Toda, Irene Martínez; Cruces, Julia; Garrido, Antonio; Gonzalez-Sanchez, Mónica; De la Fuente, Mónica

    2017-08-01

    The age-related changes in the immune functions (immunosenescence) may be mediated by an increase of oxidative stress and damage affecting leukocytes. Although the "oxidation-inflammation" theory of aging proposes that phagocytes are the main immune cells contributing to "oxi-inflamm-aging", this idea has not been corroborated. The aim of this work was to characterize the age-related changes in several parameters of oxidative stress and immune function, as well as in lipofuscin accumulation ("a hallmark of aging"), in both total peritoneal leukocyte population and isolated peritoneal macrophages. Adult, mature, old and long-lived mice (7, 13, 18 and 30 months of age, respectively) were used. The xanthine oxidase (XO) activity-expression, basal levels of superoxide anion and ROS, catalase activity, oxidized (GSSG) and reduced (GSH) glutathione content and lipofuscin levels, as well as both phagocytosis and digestion capacity were evaluated. The results showed an age-related increase of oxidative stress and lipofuscin accumulation in murine peritoneal leukocytes, but especially in macrophages. Macrophages from old mice showed lower antioxidant defenses (catalase activity and GSH levels), higher oxidizing compounds (XO activity/expression and superoxide, ROS and GSSG levels) and lipofuscin levels, together with an impaired macrophage functions, in comparison to adults. In contrast, long-lived mice showed in their peritoneal leukocytes, and especially in macrophages, a well-preserved redox state and maintenance of their immune functions, all which could account for their high longevity. Interestingly, macrophages showed higher XO activity and lipofuscin accumulation than lymphocytes in all the ages analyzed. Our results support that macrophages play a central role in the chronic oxidative stress associated with aging, and the fact that phagocytes are key cells contributing to immunosenescence and "oxi-inflamm-aging". Moreover, the determination of oxidative stress and

  4. Cholesterol Accumulation in CD11c(+) Immune Cells Is a Causal and Targetable Factor in Autoimmune Disease.

    Science.gov (United States)

    Ito, Ayaka; Hong, Cynthia; Oka, Kazuhiro; Salazar, Jon V; Diehl, Cody; Witztum, Joseph L; Diaz, Mercedes; Castrillo, Antonio; Bensinger, Steven J; Chan, Lawrence; Tontonoz, Peter

    2016-12-20

    Liver X receptors (LXRs) are regulators of cholesterol metabolism that also modulate immune responses. Inactivation of LXR α and β in mice leads to autoimmunity; however, how the regulation of cholesterol metabolism contributes to autoimmunity is unclear. Here we found that cholesterol loading of CD11c(+) cells triggered the development of autoimmunity, whereas preventing excess lipid accumulation by promoting cholesterol efflux was therapeutic. LXRβ-deficient mice crossed to the hyperlipidemic ApoE-deficient background or challenged with a high-cholesterol diet developed autoantibodies. Cholesterol accumulation in lymphoid organs promoted T cell priming and stimulated the production of the B cell growth factors Baff and April. Conversely, B cell expansion and the development of autoantibodies in ApoE/LXR-β-deficient mice was reversed by ApoA-I expression. These findings implicate cholesterol imbalance as a contributor to immune dysfunction and suggest that stimulating HDL-dependent reverse cholesterol transport could be beneficial in the setting of autoimmune disease. Copyright © 2016 Elsevier Inc. All rights reserved.

  5. The Dietary Constituent Falcarindiol Promotes Cholesterol Efflux from THP-1 Macrophages by Increasing ABCA1 Gene Transcription and Protein Stability

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    Limei Wang

    2017-09-01

    Full Text Available We report increased cholesterol efflux from macrophages in the presence of falcarindiol, an important dietary constituent present in commonly used vegetables and medicinal plants. Falcarindiol (3–20 μM increased cholesterol efflux from THP-1-derived macrophages. Western blot analysis showed an increased protein level of ABCA1 upon falcarindiol exposure. Quantitative real-time PCR revealed that also ABCA1 mRNA level rise with falcarindiol (10 μM treatment. The effect of falcarindiol on ABCA1 protein as well as mRNA level were counteracted by co-treatment with BADGE, an antagonist of PPARγ. Furthermore, falcarindiol significantly inhibited ABCA1 protein degradation in the presence of cycloheximide. This post-translational regulation of ABCA1 by falcarindiol occurs most likely by inhibition of lysosomal cathepsins, resulting in decreased proteolysis and extended protein half-life of ABCA1. Taken together, falcarindiol increases ABCA1 protein level by two complementary mechanisms, i.e., promoting ABCA1 gene expression and inhibiting ABCA1 protein degradation, which lead to enhanced cholesterol efflux.

  6. Accumulation of low density lipoprotein associated cholesterol in calcifying vesicle fractions correlates with intimal thickening in thoracic aortas of juvenile rabbits fed a supplemental cholesterol diet

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    Culley Nathan C

    2006-10-01

    Full Text Available Abstract Background It has been shown that calcifying vesicles play an important role in aortic calcification and that cholesterol content in the isolated vesicle fraction is increased when rabbits are fed supplemental cholesterol diets. Whether lipoprotein-associated cholesterols and other lipids are also increased in the vesicle fraction and whether the increase correlates with atherosclerosis remain unknown. Results Fourteen juvenile male rabbits fed an atherogenic diet containing 0.5% cholesterol and 2% peanut oil for 3 months developed varying degrees of hypercholesterolemia and intimal thickening in the ascending thoracic aorta. The correlation between these two parameters was insignificant, and likely attributable to the use of small numbers of rabbits in this study. Despite this lack of correlation, we demonstrate that the accumulation of cholesterol in calcifying vesicle fractions obtained from the collagenase-digested aorta fragments correlates well with intimal thickening (r2 = 0.98, p Conclusion When limited numbers of rabbits are used, LDL-C accumulation in calcifying vesicle fractions is a better biomarker for atherosclerosis than LDL-C levels in the serum. The close association of LDL-C with calcifying vesicles may play an important role in atherosclerosis and calcification.

  7. N370S-GBA1 mutation causes lysosomal cholesterol accumulation in Parkinson's disease.

    Science.gov (United States)

    García-Sanz, Patricia; Orgaz, Lorena; Bueno-Gil, Guillermo; Espadas, Isabel; Rodríguez-Traver, Eva; Kulisevsky, Jaime; Gutierrez, Antonia; Dávila, José C; González-Polo, Rosa A; Fuentes, José M; Mir, Pablo; Vicario, Carlos; Moratalla, Rosario

    2017-08-05

    Heterozygous mutations in the GBA1 gene, which encodes the lysosomal enzyme β-glucocerebrosidase-1, increase the risk of developing Parkinson's disease, although the underlying mechanisms remain unclear. The aim of this study was to explore the impact of the N370S-GBA1 mutation on cellular homeostasis and vulnerability in a patient-specific cellular model of PD. We isolated fibroblasts from 4 PD patients carrying the N370S/wild type GBA1 mutation and 6 controls to study the autophagy-lysosome pathway, endoplasmic reticulum stress, and Golgi apparatus structure by Western blot, immunofluorescence, LysoTracker and Filipin stainings, mRNA analysis, and electron microscopy. We evaluated cell vulnerability by apoptosis, reactive oxygen species and mitochondrial membrane potential with flow cytometry. The N370S mutation produced a significant reduction in β-glucocerebrosidase-1 protein and enzyme activity and β-glucocerebrosidase-1 retention within the endoplasmic reticulum, which interrupted its traffic to the lysosome. This led to endoplasmic reticulum stress activation and triggered unfolded protein response and Golgi apparatus fragmentation. Furthermore, these alterations resulted in autophagosome and p62/SQSTM1 accumulation. This impaired autophagy was a result of dysfunctional lysosomes, indicated by multilamellar body accumulation probably caused by increased cholesterol, enlarged lysosomal mass, and reduced enzyme activity. This phenotype impaired the removal of damaged mitochondria and reactive oxygen species production and enhanced cell death. Our results support a connection between the loss of β-glucocerebrosidase-1 function, cholesterol accumulation, and the disruption of cellular homeostasis in GBA1-PD. Our work reveals new insights into the cellular pathways underlying PD pathogenesis, providing evidence that GBA1-PD shares common features with lipid-storage diseases. © 2017 International Parkinson and Movement Disorder Society. © 2017 International

  8. Antibiotic-induced imbalances in gut microbiota aggravates cholesterol accumulation and liver injuries in rats fed a high-cholesterol diet.

    Science.gov (United States)

    Hu, Xu; Wang, Tao; Liang, Shan; Li, Wei; Wu, Xiaoli; Jin, Feng

    2015-11-01

    Increasing evidence suggests that maintenance of homeostasis between gut microbiota and host plays an important role in human health. Many diseases, such as those affecting the liver, have been linked to imbalances in gut microbial communities. However, it is not clear whether an imbalance in gut microbiota promotes the onset of liver injury or if the imbalance results from the pathological state. In the current study, antibiotics were used to disturb the gut microbiota of both rats fed a high-cholesterol diet and rats fed a normal diet (controls). The prevalence of Bacteroidetes and Firmicutes were reduced, and Proteobacteria was greatly increased in the guts of rats after antibiotic treatment. The antibiotic-induced perturbation of gut microbiota aggravated cholesterol accumulation and liver injury in rats fed a high-cholesterol diet. This may have been due to an increase in intestinal permeability and plasma lipopolysaccharide (LPS), which lead to an increase in LPS absorption and activation of TLR4 signaling, resulting in the synthesis of pro-inflammatory cytokines and chemokines in liver tissues. This study suggests that imbalances in gut microbiota may be a predisposing factor for the onset of metabolic diseases and liver injuries related to cholesterol and high-cholesterol diets. Modulation of gut microbiota could be a novel target for preventing cholesterol-related metabolic disorders.

  9. Aerobic Exercise Training Selectively Changes Oxysterol Levels and Metabolism Reducing Cholesterol Accumulation in the Aorta of Dyslipidemic Mice

    Directory of Open Access Journals (Sweden)

    Guilherme Silva Ferreira

    2017-09-01

    Full Text Available Background: Oxysterols are bioactive lipids that control cellular cholesterol synthesis, uptake, and exportation besides mediating inflammation and cytotoxicity that modulate the development of atherosclerosis. Aerobic exercise training (AET prevents and regresses atherosclerosis by the improvement of lipid metabolism, reverse cholesterol transport (RCT and antioxidant defenses in the arterial wall. We investigated in dyslipidemic mice the role of a 6-week AET program in the content of plasma and aortic arch cholesterol and oxysterols, the expression of genes related to cholesterol flux and the effect of the exercise-mimetic AICAR, an AMPK activator, in macrophage oxysterols concentration.Methods: Sixteen-week old male apo E KO mice fed a chow diet were included in the protocol. Animals were trained in a treadmill running, 15 m/min, 5 days/week, for 60 min (T; n = 29. A control group was kept sedentary (S; n = 32. Plasma lipids and glucose were determined by enzymatic techniques and glucometer, respectively. Cholesterol and oxysterols in aortic arch and macrophages were measured by gas chromatography/mass spectrometry. The expression of genes involved in lipid metabolism was determined by RT-qPCR. The effect of AMPK in oxysterols metabolism was determined in J774 macrophages treated with 0.25 mM AICAR.Results: Body weight and plasma TC, TG, HDL-c, glucose, and oxysterols were similar between groups. As compared to S group, AET enhanced 7β-hydroxycholesterol (70% and reduced cholesterol (32% in aorta. In addition, exercise increased Cyp27a1 (54%, Cd36 (75%, Cat (70%, Prkaa1 (40%, and Prkaa2 (51% mRNA. In macrophages, the activation of AMPK followed by incubation with HDL2 increased Abca1 (52% and Cd36 (220% and decrease Prkaa1 (19%, Cyp27a1 (47% and 7α-hydroxycholesterol level.Conclusion: AET increases 7β-hydroxycholesterol in the aortic arch of dyslipidemic mice, which is related to the enhanced expression of Cd36. In addition, the increase

  10. Simvastatin promotes NPC1-mediated free cholesterol efflux from lysosomes through CYP7A1/LXRα signalling pathway in oxLDL-loaded macrophages.

    Science.gov (United States)

    Xu, Xiaoyang; Zhang, Aolin; Halquist, Matthew S; Yuan, Xinxu; Henderson, Scott C; Dewey, William L; Li, Pin-Lan; Li, Ningjun; Zhang, Fan

    2017-02-01

    Statins, 3-hydroxyl-3-methylglutaryl coenzyme A reductase inhibitors, are the first-line medications prescribed for the prevention and treatment of coronary artery diseases. The efficacy of statins has been attributed not only to their systemic cholesterol-lowering actions but also to their pleiotropic effects that are unrelated to cholesterol reduction. These pleiotropic effects have been increasingly recognized as essential in statins therapy. This study was designed to investigate the pleiotropic actions of simvastatin, one of the most commonly prescribed statins, on macrophage cholesterol homeostasis with a focus on lysosomal free cholesterol egression. With simultaneous nile red and filipin staining, analysis of confocal/multi-photon imaging demonstrated that simvastatin markedly attenuated unesterified (free) cholesterol buildup in macrophages loaded with oxidized low-density lipoprotein but had little effect in reducing the sizes of cholesteryl ester-containing lipid droplets; the reduction in free cholesterol was mainly attributed to decreases in lysosome-compartmentalized cholesterol. Functionally, the egression of free cholesterol from lysosomes attenuated pro-inflammatory cytokine secretion. It was determined that the reduction of lysosomal free cholesterol buildup by simvastatin was due to the up-regulation of Niemann-Pick C1 (NPC1), a lysosomal residing cholesterol transporter. Moreover, the enhanced enzymatic production of 7-hydroxycholesterol by cytochrome P450 7A1 and the subsequent activation of liver X receptor α underscored the up-regulation of NPC1. These findings reveal a novel pleiotropic effect of simvastatin in affecting lysosomal cholesterol efflux in macrophages and the associated significance in the treatment of atherosclerosis. © 2016 The Authors. Journal of Cellular and Molecular Medicine published by John Wiley & Sons Ltd and Foundation for Cellular and Molecular Medicine.

  11. Cholesterol accumulation in Niemann Pick type C (NPC) model cells causes a shift in APP localization to lipid rafts

    Energy Technology Data Exchange (ETDEWEB)

    Kosicek, Marko, E-mail: marko.kosicek@irb.hr [Division of Molecular Medicine, Ruder Boskovic Institute, Bijenicka 54, 10000 Zagreb (Croatia); Malnar, Martina, E-mail: martina.malnar@irb.hr [Division of Molecular Medicine, Ruder Boskovic Institute, Bijenicka 54, 10000 Zagreb (Croatia); Goate, Alison, E-mail: goate@icarus.wustl.edu [Department of Psychiatry, Washington University School of Medicine, 660 S. Euclid Ave., St. Louis, MO 63110 (United States); Hecimovic, Silva, E-mail: silva.hecimovic@irb.hr [Division of Molecular Medicine, Ruder Boskovic Institute, Bijenicka 54, 10000 Zagreb (Croatia)

    2010-03-12

    It has been suggested that cholesterol may modulate amyloid-{beta} (A{beta}) formation, a causative factor of Alzheimer's disease (AD), by regulating distribution of the three key proteins in the pathogenesis of AD ({beta}-amyloid precursor protein (APP), {beta}-secretase (BACE1) and/or presenilin 1 (PS1)) within lipid rafts. In this work we tested whether cholesterol accumulation upon NPC1 dysfunction, which causes Niemann Pick type C disease (NPC), causes increased partitioning of APP into lipid rafts leading to increased CTF/A{beta} formation in these cholesterol-rich membrane microdomains. To test this we used CHO NPC1{sup -/-} cells (NPC cells) and parental CHOwt cells. By sucrose density gradient centrifugation we observed a shift in fl-APP/CTF compartmentalization into lipid raft fractions upon cholesterol accumulation in NPC vs. wt cells. Furthermore, {gamma}-secretase inhibitor treatment significantly increased fl-APP/CTF distribution in raft fractions in NPC vs. wt cells, suggesting that upon cholesterol accumulation in NPC1-null cells increased formation of APP-CTF and its increased processing towards A{beta} occurs in lipid rafts. Our results support that cholesterol overload, such as in NPC disease, leads to increased partitioning of APP/CTF into lipid rafts resulting in increased amyloidogenic processing of APP in these cholesterol-rich membranes. This work adds to the mechanism of the cholesterol-effect on APP processing and the pathogenesis of Alzheimer's disease and supports the role of lipid rafts in these processes.

  12. Adipocyte progenitor cells initiate monocyte chemoattractant protein-1-mediated macrophage accumulation in visceral adipose tissue

    Directory of Open Access Journals (Sweden)

    Jennifer L. Kaplan

    2015-11-01

    Conclusions: This study provides the first in vivo evidence, to our knowledge, that committed AdPCs in VAT are the initial source of obesity-induced MCP-1 and identifies the helix-loop-helix transcription factor Id3 as a critical regulator of p21Cip1 expression, AdPC proliferation, MCP-1 expression and M1 macrophage accumulation in VAT. Inhibition of Id3 and AdPC expansion, as well as CD44 expression in human AdPCs, may serve as unique therapeutic targets for the regulation of adipose tissue inflammation.

  13. Niemann-Pick Type C2 Protein Mediates Hepatic Stellate Cells Activation by Regulating Free Cholesterol Accumulation

    Directory of Open Access Journals (Sweden)

    Yuh-Ching Twu

    2016-07-01

    Full Text Available In chronic liver diseases, regardless of their etiology, the development of fibrosis is the first step toward the progression to cirrhosis, portal hypertension, and hepatocellular carcinoma. Hepatic stellate cells (HSCs are the main profibrogenic cells that promote the pathogenesis of liver fibrosis, and so it is important to identify the molecules that regulate HSCs activation and liver fibrosis. Niemann-Pick type C2 (NPC2 protein plays an important role in the regulation of intracellular cholesterol homeostasis by directly binding with free cholesterol. However, the roles of NPC2 in HSCs activation and liver fibrosis have not been explored in detail. Since a high-cholesterol diet exacerbates liver fibrosis progression in both rodents and humans, we propose that the expression of NPC2 affects free cholesterol metabolism and regulates HSCs activation. In this study, we found that NPC2 is decreased in both thioacetamide- and carbon tetrachloride-induced liver fibrosis tissues. In addition, NPC2 is expressed in quiescent HSCs, but its activation status is down-regulated. Knockdown of NPC2 in HSC-T6 cells resulted in marked increases in transforming growth factor-β1 (TGF-β1-induced collagen type 1 α1 (Col1a1, α-smooth muscle actin (α-SMA expression, and Smad2 phosphorylation. In contrast, NPC2 overexpression decreased TGF-β1-induced HSCs activation. We further demonstrated that NPC2 deficiency significantly increased the accumulation of free cholesterol in HSCs, increasing Col1a1 and α-SMA expression and activating Smad2, and leading to sensitization of HSCs to TGF-β1 activation. In contrast, overexpression of NPC2 decreased U18666A-induced free cholesterol accumulation and inhibited the subsequent HSCs activation. In conclusion, our study has demonstrated that NPC2 plays an important role in HSCs activation by regulating the accumulation of free cholesterol. NPC2 overexpression may thus represent a new treatment strategy for liver fibrosis.

  14. Niemann-Pick Type C2 Protein Mediates Hepatic Stellate Cells Activation by Regulating Free Cholesterol Accumulation.

    Science.gov (United States)

    Twu, Yuh-Ching; Lee, Tzong-Shyuan; Lin, Yun-Lian; Hsu, Shih-Ming; Wang, Yuan-Hsi; Liao, Chia-Yu; Wang, Chung-Kwe; Liang, Yu-Chih; Liao, Yi-Jen

    2016-07-13

    In chronic liver diseases, regardless of their etiology, the development of fibrosis is the first step toward the progression to cirrhosis, portal hypertension, and hepatocellular carcinoma. Hepatic stellate cells (HSCs) are the main profibrogenic cells that promote the pathogenesis of liver fibrosis, and so it is important to identify the molecules that regulate HSCs activation and liver fibrosis. Niemann-Pick type C2 (NPC2) protein plays an important role in the regulation of intracellular cholesterol homeostasis by directly binding with free cholesterol. However, the roles of NPC2 in HSCs activation and liver fibrosis have not been explored in detail. Since a high-cholesterol diet exacerbates liver fibrosis progression in both rodents and humans, we propose that the expression of NPC2 affects free cholesterol metabolism and regulates HSCs activation. In this study, we found that NPC2 is decreased in both thioacetamide- and carbon tetrachloride-induced liver fibrosis tissues. In addition, NPC2 is expressed in quiescent HSCs, but its activation status is down-regulated. Knockdown of NPC2 in HSC-T6 cells resulted in marked increases in transforming growth factor-β1 (TGF-β1)-induced collagen type 1 α1 (Col1a1), α-smooth muscle actin (α-SMA) expression, and Smad2 phosphorylation. In contrast, NPC2 overexpression decreased TGF-β1-induced HSCs activation. We further demonstrated that NPC2 deficiency significantly increased the accumulation of free cholesterol in HSCs, increasing Col1a1 and α-SMA expression and activating Smad2, and leading to sensitization of HSCs to TGF-β1 activation. In contrast, overexpression of NPC2 decreased U18666A-induced free cholesterol accumulation and inhibited the subsequent HSCs activation. In conclusion, our study has demonstrated that NPC2 plays an important role in HSCs activation by regulating the accumulation of free cholesterol. NPC2 overexpression may thus represent a new treatment strategy for liver fibrosis.

  15. Curcumin enhanced cholesterol efflux by upregulating ABCA1 expression through AMPK-SIRT1-LXRα signaling in THP-1 macrophage-derived foam cells.

    Science.gov (United States)

    Lin, Xiao-long; Liu, Mi-Hua; Hu, Hui-Jun; Feng, Hong-ru; Fan, Xiao-Juan; Zou, Wei-wen; Pan, Yong-quan; Hu, Xue-mei; Wang, Zuo

    2015-09-01

    Curcumin, a traditional Chinese derivative from the rhizomes of Curcuma longa, is beneficial to health by modulating lipid metabolism and suppressing atherogenesis. A key part of atherosclerosis is the failure of macrophages to restore their cellular cholesterol homeostasis and the formation of foam cells. In this study, results showed that curcumin dramatically increased the expression of ATP-binding cassette transporter 1 (ABCA1), promoted cholesterol efflux from THP-1 macrophage-derived foam cells, and reduced cellular cholesterol levels. Curcumin activated AMP-activated protein kinase (AMPK) and SIRT1, and then activated LXRα in THP-1 macrophage-derived foam cells. Inhibiting AMPK/SIRT1 activity by its specific inhibitor or by small interfering RNA could inhibit LXRα activation and abolish curcumin-induced ABCA1 expression and cholesterol efflux. Thus, curcumin enhanced cholesterol efflux by upregulating ABCA1 expression through activating AMPK-SIRT1-LXRα signaling in THP-1 macrophage-derived foam cells. This study describes a possible mechanism for understanding the antiatherogenic effects of curcumin on attenuating the progression of atherosclerosis.

  16. Hexadecylphosphocholine disrupts cholesterol homeostasis and induces the accumulation of free cholesterol in HepG2 tumour cells.

    Science.gov (United States)

    Jiménez-López, José M; Carrasco, María P; Marco, Carmen; Segovia, Josefa L

    2006-04-14

    Hexadecylphosphocholine (HePC) is a synthetic lipid belonging to the alkylphosphocholines (APC), a new group of antiproliferative agents that are proving to be promising candidates in anticancer therapy. We reported in a previous study that HePC interferes with phosphatidylcholine (PC) synthesis in HepG2 cells via both CDP-choline and phosphatidylethanolamine (PE) methylation. We have subsequently extended our studies to show that HePC interferes with sphingolipid metabolism by hindering the formation of sphingomyelin (SM), an effect accompanied by a substantial increase in the incorporation of the exogenous lipogenic precursors into ceramides. Interestingly, we demonstrate for the first time that HePC strongly inhibits the esterification of free cholesterol (FC) by acting at the level of acyl CoA:cholesterol acyltransferase (ACAT) (EC 2.3.1.26) activity. This effect is accompanied by a considerable increase in the synthesis of cholesterol, which leads to a rise in the levels of FC in cells. We are left in no doubt that the imbalance in the metabolism of membrane-lipid components vital to cell survival may well be responsible for the observed DNA fragmentation and activation of caspase-3, an enzyme involved in the cell apoptosis found in this study.

  17. Evaluation of the effects of chemically different linkers on hepatic accumulations, cell tropism and gene silencing ability of cholesterol-conjugated antisense oligonucleotides.

    Science.gov (United States)

    Wada, Shunsuke; Yasuhara, Hidenori; Wada, Fumito; Sawamura, Motoki; Waki, Reiko; Yamamoto, Tsuyoshi; Harada-Shiba, Mariko; Obika, Satoshi

    2016-03-28

    Cholesterol conjugation of oligonucleotides is an attractive way to deliver the oligonucleotides specifically to the liver. However cholesterol-conjugated antisense oligonucleotides (ASOs) mainly accumulate in non-parenchymal cells (NPCs) such as Kupffer cells. In this study, to increase the hepatic accumulation of cholesterol-conjugated ASOs, we prepared a variety of linkers for cholesterol conjugation to anti-Pcsk9 ASOs and examined their effects on pharmacological parameters. Hepatic accumulation of ASO was dramatically increased with cholesterol conjugation. The increase in hepatic accumulation depended largely on the linker chemistry of each cholesterol-conjugated ASO. In addition to hepatic accumulation, the cell tropism of each cholesterol-conjugated ASO tended to depend on their linker. Although a linker bearing a disulfide bond accumulated mainly in NPCs, hexamethylene succinimide linker accumulated mainly in hepatocytes. To estimate the benefits of releasing ASO from the conjugated cholesterol in hepatocyte, we designed another linker based on hexamethylene succinimide, which has a phosphodiester bond between the linker and the ASO. The cholesterol-conjugated ASO bearing such a phosphodiester bond showed a significantly improved Pcsk9 mRNA inhibitory effect compared to its counterpart, cholesterol-conjugated ASO with a phosphorothioate bond, while the hepatic accumulation of both cholesterol-conjugated ASOs was comparable, indicating the effectiveness of removing the conjugated cholesterol for ASO activity. In toxicity analysis, some of the linkers induced lethal toxicities when they were injected at high concentrations (>600μM). These toxicities were attributed to decreased platelet levels in the blood, suggesting an interaction between cholesterol-conjugated ASO and platelets. Our findings may provide a guideline for the design of molecule-conjugated ASOs. Copyright © 2016 Elsevier B.V. All rights reserved.

  18. Visceral fat accumulation is an indicator of adipose tissue macrophage infiltration in women.

    Science.gov (United States)

    Michaud, Andréanne; Drolet, Renée; Noël, Suzanne; Paris, Gaëtan; Tchernof, André

    2012-05-01

    We tested the hypothesis that visceral obesity is the best correlate of abdominal adipose tissue macrophage infiltration in women. Omental and subcutaneous fat samples were surgically obtained from 40 women (age, 47.0 ± 4.0 years; body mass index, 28.4 ± 5.8 kg/m(2)). CD68+ cells were identified using fluorescence immunohistochemistry. Expression of macrophage markers was measured by real-time reverse transcriptase polymerase chain reaction. Body composition and fat distribution were measured by dual-energy x-ray absorptiometry and computed tomography, respectively. Mean CD68+ cell percentage tended to be higher in subcutaneous (18.3%) compared with omental adipose tissue (15.5%, P = .07). Positive correlations were observed between CD68+ cell percentage as well as CD68 messenger RNA expression in a given depot vs the other (P ≤ .01). Visceral adipose tissue area and omental adipocyte diameter were positively related to CD68+ cell percentage in omental fat (r = 0.52 and r = 0.35, P ≤ .05). Total and visceral adipose tissue areas as well as subcutaneous adipocyte diameter were significantly correlated with CD68+ cell percentage in subcutaneous adipose tissue (0.32 ≤ r ≤ 0.40, P ≤ .05). Adipose tissue areas and subcutaneous adipocyte diameter were also significantly associated with expression of commonly used macrophage markers including CD68 in the subcutaneous fat compartment (0.32 ≤ r ≤ 0.57, P ≤ .05). Visceral adipose tissue area was the best correlate of CD68+ cell percentage in both omental and subcutaneous fat tissues, explaining, respectively, 20% and 12% of the variance in models also including subcutaneous adipose tissue area, adipocyte sizes, and total body fat mass. Visceral adipose tissue accumulation is the best correlate of macrophage infiltration in both the subcutaneous and omental fat compartments of lean to obese women.

  19. Metformin reduces lipid accumulation in macrophages by inhibiting FOXO1-mediated transcription of fatty acid-binding protein 4

    Energy Technology Data Exchange (ETDEWEB)

    Song, Jun [Qilu Hospital, Shandong University, Jinan, Shandong (China); Division of Cardiothoracic Surgery, Michael E. DeBakey Department of Surgery, Baylor College of Medicine, Houston, TX (United States); Texas Heart Institute at St. Luke' s Episcopal Hospital, Houston, TX (United States); Ren, Pingping; Zhang, Lin [Division of Cardiothoracic Surgery, Michael E. DeBakey Department of Surgery, Baylor College of Medicine, Houston, TX (United States); Texas Heart Institute at St. Luke' s Episcopal Hospital, Houston, TX (United States); Wang, Xing Li [Qilu Hospital, Shandong University, Jinan, Shandong (China); Division of Cardiothoracic Surgery, Michael E. DeBakey Department of Surgery, Baylor College of Medicine, Houston, TX (United States); Texas Heart Institute at St. Luke' s Episcopal Hospital, Houston, TX (United States); Chen, Li [Qilu Hospital, Shandong University, Jinan, Shandong (China); Shen, Ying H., E-mail: hyshen@bcm.edu [Division of Cardiothoracic Surgery, Michael E. DeBakey Department of Surgery, Baylor College of Medicine, Houston, TX (United States); Texas Heart Institute at St. Luke' s Episcopal Hospital, Houston, TX (United States)

    2010-02-26

    Objective: The accumulation of lipids in macrophages contributes to the development of atherosclerosis. Strategies to reduce lipid accumulation in macrophages may have therapeutic potential for preventing and treating atherosclerosis and cardiovascular complications. The antidiabetic drug metformin has been reported to reduce lipid accumulation in adipocytes. In this study, we examined the effects of metformin on lipid accumulation in macrophages and investigated the mechanisms involved. Methods and results: We observed that metformin significantly reduced palmitic acid (PA)-induced intracellular lipid accumulation in macrophages. Metformin promoted the expression of carnitine palmitoyltransferase I (CPT-1), while reduced the expression of fatty acid-binding protein 4 (FABP4) which was involved in PA-induced lipid accumulation. Quantitative real-time PCR showed that metformin regulates FABP4 expression at the transcriptional level. We identified forkhead transcription factor FOXO1 as a positive regulator of FABP4 expression. Inhibiting FOXO1 expression with FOXO1 siRNA significantly reduced basal and PA-induced FABP4 expression. Overexpression of wild-type FOXO1 and constitutively active FOXO1 significantly increased FABP4 expression, whereas dominant negative FOXO1 dramatically decreased FABP4 expression. Metformin reduced FABP4 expression by promoting FOXO1 nuclear exclusion and subsequently inhibiting its activity. Conclusions: Taken together, these results suggest that metformin reduces lipid accumulation in macrophages by repressing FOXO1-mediated FABP4 transcription. Thus, metformin may have a protective effect against lipid accumulation in macrophages and may serve as a therapeutic agent for preventing and treating atherosclerosis in metabolic syndrome.

  20. Effect of Apolipoprotein A-I on ATP Binding Cassette Transporter A1 Degradation and Cholesterol Efflux in THP-1 Macrophage-derived Foam Cells

    Institute of Scientific and Technical Information of China (English)

    Chao-Ke TANG; Chang-Geng RUAN; Yong-Zong YANG; Guo-Hua TANG; Guang-Hui IY; Zuo WANG; Lu-Shan LIU; Shuang WAN; Zhong-Hua YUAN; Xiu-Sheng HE; Jun-Hao YANG

    2004-01-01

    Cholesterol-loaded macrophage foam cells are a central componentof atherosclerotic lesions ATP binding cassette transporter A1(ABCA1),the defective molecule in Tangier disease,mediates the efflux ofphospholipid and cholesterol from cells to apolipoprotein A-I(apoA-I),reversing foam cell formation.This study investigated the effect of apoA-I on ABCA1 degradation and cholesterol efflux in THP-1 macrophagederived foam cells.After exposure of the cultured THP-1 macrophage-derived foam cells to apoA-I for different time,cholesterol efflux,ABCA1 mRNA and protein levels were determined by FJ-2107P type liquid scintillator,RT-PCR and Western blot,respectively.The mean ABCA1 fluorescence intensity on THP-1macrophage-derived foam cells was detected by flow cytometry.Results showed that apoA-I markedly increased ABCAl-mediated cholesterol efflux from THP-1 macrophage-derived foam cells.This was accompanied by an increase in the content of ABCA1.ApoA-I did not alter ABCA 1 mRNA abundance.Significantly,thiol protease inhibitors increased the level ofABCA1 protein and slowed its decay in THP-1macrophage-derived foam cells,whereas none of the proteosome-specific inhibitor lactacystin,other protease inhibitors,or the lysosomal inhibitor NH4Cl showed such effects.The apoA-I-mediated cellular cholesterol efflux was enhanced by thiol protease inhibitors.Our results suggested that thiol protease inhibitors mightprovide an alternative way to upregulate ABCA1 protein.This strategy is especially appealing since it may mimic the stabilizing effect of the natural ligands apoA-I.

  1. Restoring Mitochondrial Function: A Small Molecule-mediated Approach to Enhance Glucose Stimulated Insulin Secretion in Cholesterol Accumulated Pancreatic beta cells

    Science.gov (United States)

    Asalla, Suman; Girada, Shravan Babu; Kuna, Ramya S.; Chowdhury, Debabrata; Kandagatla, Bhaskar; Oruganti, Srinivas; Bhadra, Utpal; Bhadra, Manika Pal; Kalivendi, Shasi Vardhan; Rao, Swetha Pavani; Row, Anupama; Ibrahim, A.; Ghosh, Partha Pratim; Mitra, Prasenjit

    2016-06-01

    Dyslipidemia, particularly the elevated serum cholesterol levels, aggravate the pathophysiology of type 2 diabetes. In the present study we explored the relationship between fasting blood sugar and serum lipid parameters in human volunteers which revealed a significant linear effect of serum cholesterol on fasting blood glucose. Short term feeding of cholesterol enriched diet to rodent model resulted in elevated serum cholesterol levels, cholesterol accumulation in pancreatic islets and hyperinsulinemia with modest increase in plasma glucose level. To explore the mechanism, we treated cultured BRIN-BD11 pancreatic beta cells with soluble cholesterol. Our data shows that cholesterol treatment of cultured pancreatic beta cells enhances total cellular cholesterol. While one hour cholesterol exposure enhances insulin exocytosis, overnight cholesterol accumulation in cultured pancreatic beta cells affects cellular respiration, and inhibits Glucose stimulated insulin secretion. We further report that (E)-4-Chloro-2-(1-(2-(2,4,6-trichlorophenyl) hydrazono) ethyl) phenol (small molecule M1) prevents the cholesterol mediated blunting of cellular respiration and potentiates Glucose stimulated insulin secretion which was abolished in pancreatic beta cells on cholesterol accumulation.

  2. Rotator cuff tear reduces muscle fiber specific force production and induces macrophage accumulation and autophagy.

    Science.gov (United States)

    Gumucio, Jonathan P; Davis, Max E; Bradley, Joshua R; Stafford, Patrick L; Schiffman, Corey J; Lynch, Evan B; Claflin, Dennis R; Bedi, Asheesh; Mendias, Christopher L

    2012-12-01

    Full-thickness tears to the rotator cuff can cause severe pain and disability. Untreated tears progress in size and are associated with muscle atrophy and an infiltration of fat to the area, a condition known as "fatty degeneration." To improve the treatment of rotator cuff tears, a greater understanding of the changes in the contractile properties of muscle fibers and the molecular regulation of fatty degeneration is essential. Using a rat model of rotator cuff injury, we measured the force generating capacity of individual muscle fibers and determined changes in muscle fiber type distribution that develop after a full thickness rotator cuff tear. We also measured the expression of mRNA and miRNA transcripts involved in muscle atrophy, lipid accumulation, and matrix synthesis. We hypothesized that a decrease in specific force of rotator cuff muscle fibers, an accumulation of type IIb fibers, and an upregulation in fibrogenic, adipogenic, and inflammatory gene expression occur in torn rotator cuff muscles. Thirty days following rotator cuff tear, we observed a reduction in muscle fiber force production, an induction of fibrogenic, adipogenic, and autophagocytic mRNA and miRNA molecules, and a dramatic accumulation of macrophages in areas of fat accumulation. Copyright © 2012 Orthopaedic Research Society.

  3. Diversity of glycosphingolipid GM2 and cholesterol accumulation in NPC1 patient-specific iPSC-derived neurons.

    Science.gov (United States)

    Trilck, Michaela; Peter, Franziska; Zheng, Chaonan; Frank, Marcus; Dobrenis, Kostantin; Mascher, Hermann; Rolfs, Arndt; Frech, Moritz J

    2017-02-15

    Niemann-Pick disease Type C1 (NPC1) is a rare progressive neurodegenerative disorder caused by mutations in the NPC1 gene. On the cellular level NPC1 mutations lead to an accumulation of cholesterol and gangliosides. As a thorough analysis of the severely affected neuronal cells is unfeasible in NPC1 patients, we recently described the cellular phenotype of neuronal cells derived from NPC1 patient iPSCs carrying the compound heterozygous mutation c.1836A>C/c.1628delC. Here we expanded the analysis to cell lines carrying the prevalent mutation c.3182T>C and the novel mutation c.1180T>C, as well as to the determination of GM2 and GM3 gangliosides in NPC1 patient-specific iPSC-derived neurons and glia cells. Immunocytochemical detection of GM2 revealed punctated staining pattern predominantly localized in neurons. Detection of cholesterol by filipin staining showed a comparable staining pattern, colocalized with GM2, indicating a deposit of GM2 and cholesterol in the same cellular compartments. Accumulations were not only restricted to cell bodies, but were also found in the neuronal extensions. A quantification of the GM2 amount by HPLC-MS/MS confirmed significantly higher amounts in neurons carrying a mutation. Additionally, these cells displayed a lowered activity of the catabolic enzyme Hex A, but not B4GALNT1. Molecular docking simulations indicated binding of cholesterol to Hex A, suggesting cholesterol influences the GM2 degradation pathway and, subsequently, leading to the accumulation of GM2. Taken together, this is the first study showing an accumulation of GM2 in neuronal derivatives of patient-specific iPSCs and thus proving further disease-specific hallmarks in this human in vitro model of NPC1. Copyright © 2016 Elsevier B.V. All rights reserved.

  4. Inhibition of P-glycoprotein by HIV protease inhibitors increases intracellular accumulation of berberine in murine and human macrophages.

    Directory of Open Access Journals (Sweden)

    Weibin Zha

    Full Text Available BACKGROUND: HIV protease inhibitor (PI-induced inflammatory response in macrophages is a major risk factor for cardiovascular diseases. We have previously reported that berberine (BBR, a traditional herbal medicine, prevents HIV PI-induced inflammatory response through inhibiting endoplasmic reticulum (ER stress in macrophages. We also found that HIV PIs significantly increased the intracellular concentrations of BBR in macrophages. However, the underlying mechanisms of HIV PI-induced BBR accumulation are unknown. This study examined the role of P-glycoprotein (P-gp in HIV PI-mediated accumulation of BBR in macrophages. METHODOLOGY AND PRINCIPAL FINDINGS: Cultured mouse RAW264.7 macrophages, human THP-1-derived macrophages, Wild type MDCK (MDCK/WT and human P-gp transfected (MDCK/P-gp cells were used in this study. The intracellular concentration of BBR was determined by HPLC. The activity of P-gp was assessed by measuring digoxin and rhodamine 123 (Rh123 efflux. The interaction between P-gp and BBR or HIV PIs was predicated by Glide docking using Schrodinger program. The results indicate that P-gp contributed to the efflux of BBR in macrophages. HIV PIs significantly increased BBR concentrations in macrophages; however, BBR did not alter cellular HIV PI concentrations. Although HIV PIs did not affect P-gp expression, P-gp transport activities were significantly inhibited in HIV PI-treated macrophages. Furthermore, the molecular docking study suggests that both HIV PIs and BBR fit the binding pocket of P-gp, and HIV PIs may compete with BBR to bind P-gp. CONCLUSION AND SIGNIFICANCE: HIV PIs increase the concentration of BBR by modulating the transport activity of P-gp in macrophages. Understanding the cellular mechanisms of potential drug-drug interactions is critical prior to applying successful combinational therapy in the clinic.

  5. Regulation of ATP-binding cassette transporters and cholesterol efflux by glucose in primary human monocytes and murine bone marrow-derived macrophages

    Science.gov (United States)

    Individuals with type 2 diabetes mellitus are at increased risk of developing atherosclerosis. This may be partially attributable to suppression of macrophage ATP-binding cassette (ABC) transporter mediated cholesterol efflux by sustained elevated blood glucose concentrations. Two models were used...

  6. The Effects of Phellinus linteus Polysaccharide Extracts on Cholesterol Efflux in Oxidized Low-Density Lipoprotein-Loaded THP-1 Macrophages.

    Science.gov (United States)

    Li, Xiao-hui; Li, Yan; Cheng, Zhao-yun; Cai, Xi-guo; Wang, Hong-min

    2015-06-01

    The removal of excess cellular cholesterol is critical for maintaining cellular cholesterol homeostasis. Phellinus linteus polysaccharide extracts (PLPEs) is an immunomudulatory agent with a molecular weight of 153 kd. Here, we analyzed the effects of PLPEs on cholesterol efflux in oxidized low-density lipoprotein (ox-LDL)-loaded THP-1 (human acute monocytic leukemia cell line) macrophages. Various concentrations of PLPEs (5, 10, 20, and 100 μg/mL) were used to treat cells. Cholesterol efflux analysis was performed to analyze the cholesterol efflux ratio in PLPE-treated cells. Semiquantitative reverse transcription-polymerase chain reaction and Western blot analysis were conducted to assess the expression of target genes. Low dose of PLPEs (5-20 μg/mL) dose dependently enhanced cholesterol efflux to apolipoprotein A-I (ApoA-I), evidenced by promoting the expression of adenosine 5'-triphosphate (ATP)-binding cassette A1, ATP-binding cassette G1, and peroxisome proliferation-activated receptor γ, key regulators for cholesterol efflux. Moreover, GW9662, a potent antagonist of peroxisome proliferation-activated receptor γ, inhibited PLPE (20 μg/mL)-promoted cholesterol efflux to ApoA-I in a dose-dependent fashion. However, high dose of PLPEs (100 μg/mL) inhibited cholesterol efflux to ApoA-I from ox-LDL-loaded THP-1 macrophages, enhanced the production of superoxide anion, decreased mitochondrial membrane potential and ATP levels, and raised nicotinamide adenine dinucleotide/nicotinamide adenine dinucleotide phosphate oxidase subunits. Thus, these results indicate that low and high doses of PLPEs exhibit opposite effects on cholesterol efflux from ox-LDL-loaded THP-1 cells.

  7. Rice bran oil and oryzanol reduce plasma lipid and lipoprotein cholesterol concentrations and aortic cholesterol ester accumulation to a greater extent than ferulic acid in hypercholesterolemic hamsters.

    Science.gov (United States)

    Wilson, Thomas A; Nicolosi, Robert J; Woolfrey, Benjamin; Kritchevsky, David

    2007-02-01

    plasma triglyceride concentrations compared to the control (-53% and -65%, respectively) and ferulic acid (-47% and -60%, respectively) diets. Hamsters fed the control and ferulic acid diets had significantly higher plasma vitamin E concentrations compared to the RBO (201% and 161%, respectively) and oryzanol (548% and 462%, respectively) diets; the ferulic acid and oryzanol diets had significantly lower plasma lipid hydroperoxide levels than the control (-57% and -46%, respectively) diet. The oryzanol-fed hamsters excreted significantly more coprostenol and cholesterol in their feces than the ferulic acid (127% and 120%, respectively) diet. The control diet had significantly greater aortic TC and FC accumulation compared to the RBO (115% and 89%, respectively), ferulic acid (48% and 58%, respectively) and the oryzanol (74% and 70%, respectively) diets. However, only the RBO and oryzanol diets had significantly lower aortic cholesterol ester accumulation compared to the control (-73% and -46%, respectively) diet. The present study suggests that at equal dietary levels, oryzanol has a greater effect on lowering plasma non-HDL-C levels and raising plasma HDL-C than ferulic acid, possibly through a greater extent to increase fecal excretion of cholesterol and its metabolites. However, ferulic acid may have a greater antioxidant capacity via its ability to maintain serum vitamin E levels compared to RBO and oryzanol. Thus, both oryzanol and ferulic acid may exert similar antiatherogenic properties, but through different mechanisms.

  8. SIRT6 reduces macrophage foam cell formation by inducing autophagy and cholesterol efflux under ox-LDL condition.

    Science.gov (United States)

    He, Jiangping; Zhang, Guangya; Pang, Qi; Yu, Cong; Xiong, Jie; Zhu, Jing; Chen, Fengling

    2017-03-09

    SIRT6 is a pivotal regulator of lipid metabolism. It is also closely connected to cardiovascular diseases, which are the main cause of death in diabetic patients. We observed a decrease in the expression of SIRT6 and key autophagy effectors (ATG5, LC3B, and LAMP1) in ox-LDL-induced foam cells, a special form of lipid-laden macrophages. In these cells, SIRT6 WT but not SIRT6 H133Y overexpression markedly reduced foam cell formation, as shown by Oil Red O staining, while inducing autophagy flux, as determined by both mRFP-GFP-LC3 labeling and transmission electron microscopy. Silencing the key autophagy initiation gene ATG5, reversed the autophagy-promoting effect of SIRT6 in ox-LDL-treated THP1 cells, as evidenced by an increase in foam cells. Cholesterol efflux assays indicated that SIRT6 overexpression in foam cells promoted cholesterol efflux, increased the levels of ABCA1 and ABCG1, and reduced miR-33 levels. By transfecting miR-33 into cells overexpressing SIRT6, we observed that reduced foam cell formation and autophagy flux induction were largely reversed. These data imply that SIRT6 plays an essential role in protecting against atherosclerosis by reducing foam cell formation through an autophagy-dependent pathway. This article is protected by copyright. All rights reserved.

  9. Accumulation of Cholesterol Esters in ex vivo Lymphocytes from Scrapie-susceptible Sheep and in Scrapie-infected Mouse Neuroblastoma Cell Lines

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    Alessandra Pani

    2007-01-01

    Full Text Available Our studies on the role of cholesterol homeostasis in the pathogenesis of scrapie in sheep, revealed abnormal accumulation of cholesterol esters in brains and in ex vivo skin fibroblasts from genetically scrapie-susceptible, as compared to sheep with resistant genotype. We now report that PBMCs isolated from scrapie-susceptible sheep, as well as mouse neuroblastoma cell lines persistently infected with two different mouse-adapted strains of scrapie, showed similar alterations with up to 3-fold higher cholesterol ester levels than their resistant or uninfected counterparts. Treatments with drugs that interfere with intracellular cholesterol metabolism strongly reduced accumulation of cholesterol esters in scrapie-infected cell lines, whereas had significantly lower, or no effect, in uninfected cell line. These data add support to our hypothesis that accumulation of cholesterol esters may represent a biological marker of susceptibility to prion infection and a potential molecular target for prion inhibitors.

  10. 13-hydroxy linoleic acid increases expression of the cholesterol transporters ABCA1, ABCG1 and SR-BI and stimulates apoA-I-dependent cholesterol efflux in RAW264.7 macrophages

    Directory of Open Access Journals (Sweden)

    Kämmerer Ines

    2011-11-01

    Full Text Available Abstract Background Synthetic activators of peroxisome proliferator-activated receptors (PPARs stimulate cholesterol removal from macrophages through PPAR-dependent up-regulation of liver × receptor α (LXRα and subsequent induction of cholesterol exporters such as ATP-binding cassette transporter A1 (ABCA1 and scavenger receptor class B type 1 (SR-BI. The present study aimed to test the hypothesis that the hydroxylated derivative of linoleic acid (LA, 13-HODE, which is a natural PPAR agonist, has similar effects in RAW264.7 macrophages. Methods RAW264.7 macrophages were treated without (control or with LA or 13-HODE in the presence and absence of PPARα or PPARγ antagonists and determined protein levels of LXRα, ABCA1, ABCG1, SR-BI, PPARα and PPARγ and apolipoprotein A-I mediated lipid efflux. Results Treatment of RAW264.7 cells with 13-HODE increased PPAR-transactivation activity and protein concentrations of LXRα, ABCA1, ABCG1 and SR-BI when compared to control treatment (P Conclusion 13-HODE induces cholesterol efflux from macrophages via the PPAR-LXRα-ABCA1/SR-BI-pathway.

  11. Hair Growth Defects in Insig-Deficient Mice Caused by Cholesterol Precursor Accumulation and Reversed by Simvastatin

    Science.gov (United States)

    Evers, Bret M.; Farooqi, Midhat S.; Shelton, John M.; Richardson, James A.; Goldstein, Joseph L.; Brown, Michael S.; Liang, Guosheng

    2010-01-01

    Insig-1 and Insig-2, two closely related proteins, are essential for feedback inhibition of cholesterol biosynthesis. Here, we characterized a line of epidermal-specific, Insig-double knockout (Epi-Insig-DKO) mice lacking both Insigs in epidermis. At birth, Epi-Insig-DKO mice were indistinguishable from control littermates, but thereafter they failed to thrive and died before 6 weeks of age. By 14 days of age, 100% of Epi-Insig-DKO mice exhibited defects in hair growth along with other skin abnormalities, including hyperkeratosis. Hair follicles in Epi-Insig-DKO mice developed normally through postnatal day 7, but they failed to progress to later stages and thus exhibited defects in postnatal hair cycling. Insig deficiency caused a marked buildup of cholesterol precursors in skin associated with a marked increase in 3-hydroxy-3-methylglutaryl coenzyme A reductase protein. Topical treatment of Epi-Insig-DKO mice with simvastatin, an inhibitor of reductase, reduced sterol precursors in skin and corrected the hair and skin defects. We conclude that Insig deficiency in skin causes accumulation of cholesterol precursors, and this impairs normal hair development. These findings have implications for several human genetic diseases in which mutations in cholesterol biosynthetic enzymes lead to accumulation of sterol precursors and multiple cutaneous abnormalities. PMID:20090767

  12. Lipoprotein accumulation in macrophages via TLR4-dependent fluid phase uptake

    Science.gov (United States)

    Choi, Soo-Ho; Harkewicz, Richard; Lee, Jee Hyun; Boullier, Agnès; Almazan, Felicidad; Li, Andrew C.; Witztum, Joseph L.; Bae, Yun Soo; Miller, Yury I.

    2009-01-01

    Toll-like receptor-4 (TLR4) recognizes microbial pathogens, such as lipopolysaccharide (LPS), and mediates LPS-induced proinflammatory cytokine secretion, as well as microbial uptake by macrophages. In addition to exogenous pathogens, TLR4 recognizes modified self, such as minimally oxidized low-density lipoprotein (mmLDL). Here we report that mmLDL and its active components, cholesteryl ester (CE) hydroperoxides, induce TLR4-dependent fluid phase uptake typical of macropinocytosis. We show that mmLDL induced recruitment of spleen tyrosine kinase (Syk) to a TLR4 signaling complex, TLR4 phosphorylation, activation of a Vav1-Ras-Raf-MEK-ERK1/2 signaling cascade, phosphorylation of paxillin, and activation of Rac, Cdc42 and Rho. These mmLDL-induced and TLR4- and Syk-dependent signaling events and cytoskeletal rearrangements lead to enhanced uptake of small molecules, dextran and, most importantly, of both native and oxidized LDL, resulting in intracellular lipid accumulation. An intravenous injection of fluorescently labeled mmLDL in wild type mice resulted in its rapid accumulation in circulating monocytes, which was significantly attenuated in TLR4-deficient mice. These data describe a novel mechanism leading to enhanced lipoprotein uptake in macrophages that would contribute to foam cell formation and atherosclerosis. These data also suggest that CE hydroperoxides are an endogenous ligand for TLR4. As TLR4 is highly expressed on the surface of circulating monocytes in patients with chronic inflammatory conditions, and CE hydroperoxides are present in plasma, lipid uptake by monocytes in circulation may contribute to monocytes' pathological roles in chronic inflammatory diseases. PMID:19461045

  13. Differential impact of diabetes mellitus type II and arterial hypertension on collateral artery growth and concomitant macrophage accumulation.

    Science.gov (United States)

    Ito, Wulf D; Lund, Natalie; Sager, Hendrik; Becker, Wiebke; Wenzel, Ulrich

    2015-01-01

    Diabetes mellitus type II and arterial hypertension are major risk factors for peripheral arterial disease and have been considered to reduce collateral growth (arteriogenesis). Collateral growth proceeds through different stages. Vascular proliferation and macrophage accumulation are hallmarks of early collateral growth. We here compare the impact of arterial hypertension and diabetes mellitus type II on collateral proliferation (Brdu incorporation) and macrophage accumulation (ED 2 staining) as well as collateral vessel function (collateral conductance) in a rat model of peripheral vascular disease (femoral artery occlusion), diabetes mellitus type II (Zucker fatty diabetic rats and Zucker lean rat controls) and arterial hypertension (induced via clip placement around the right renal arteriy). We furthermore tested the impact of monocyte chemoattractant protein-1 (MCP‑1) on collateral proliferation and macrophage accumulation in these models Diabetic animals showed reduced vascular proliferation and macrophage accumulation, which however did not translate into a change of collateral conductance. Hypertensive animals on the contrary had reduced collateral conductances without altered macrophage accumulation and only a marginal reduction in collateral proliferation. Infusion of MCP‑1 only enhanced vascular proliferation in diabetic animals. These findings illustrate that impaired monocyte/macrophage recruitment is responsible for reduced collateral growth under diabetic conditions but not in arterial hypertension suggesting that diabetes mellitus in particular affects early stages of collateral growth whereas hypertension has its impact on later remodeling stages. Successful pro-arteriogenic treatment strategies in a patient population that presents with diabetes mellitus and arterial hypertension need to address different stages of collateral growth and thus different molecular and cellular targets simultaneously.

  14. A matrix of cholesterol crystals, but not cholesterol alone, primes human monocytes/macrophages for excessive endotoxin-induced production of tumor necrosis factor-alpha. Role in atherosclerotic inflammation?

    DEFF Research Database (Denmark)

    Bendtzen, Klaus; Christensen, Ole; Nielsen, Claus Henrik

    2014-01-01

    When exposed to small amounts of bacterial endotoxin, matrices of cholesterol crystals, but not cholesterol itself, primed human monocytes/macrophages to a highly augmented (>10-fold) production of inflammatory tumor necrosis factor-α. Priming also sensitized the cells, as 10- to 100-fold lower...... levels of endotoxin were needed for TNF-α production equivalent to that of unprimed cells. The pro-inflammatory effect was selective as endotoxin-induced production of other pro-inflammatory cytokines was unaffected while production of anti-inflammatory interleukin-10 was diminished. These findings...

  15. Temporal patterns of blood flow and nitric oxide synthase expression affect macrophage accumulation and proliferation during collateral growth

    Directory of Open Access Journals (Sweden)

    Sager Hendrik B

    2010-09-01

    Full Text Available Abstract Background The involvement of collateral blood flow/fluid shear stress, nitric oxide (NO, and macrophages during collateral growth (arteriogenesis is established, but their interplay remains paradoxical. Methods In order to further elucidate the "fluid shear stress/NO/macrophage" paradox, we investigated the time course of collateral blood flow (using a Doppler flow probe and NOS expression (immunohistochemistry, Western blot in growing rat collateral vessels after femoral artery occlusion and their impact on macrophage recruitment and collateral proliferation (immunohistochemistry, angiographies. Results (values are given as mean ± standard error of mean Early after occlusion, collateral blood flow was significantly reduced (pre- 90.0 ± 4.5 vs. post-occlusion 62.5 ± 5.9 μl/min; p p p p Conclusions We propose the following resolution of the "fluid shear stress/NO/macrophage" paradox: Collateral blood flow and NOS expression are initially reduced during arteriogenesis allowing macrophages to accumulate and therewith enhancing collateral proliferation. After homing of macrophages (24 h after occlusion, collateral blood flow and NOS expression recover in order to join the effects of macrophages for restoring blood flow.

  16. Angiopoietin Like Protein 2 (ANGPTL2) Promotes Adipose Tissue Macrophage and T lymphocyte Accumulation and Leads to Insulin Resistance

    Science.gov (United States)

    Sasaki, Yusuke; Ohta, Masayuki; Desai, Dhruv; Figueiredo, Jose-Luiz; Whelan, Mary C.; Sugano, Tomohiro; Yamabi, Masaki; Yano, Wataru; Faits, Tyler; Yabusaki, Katsumi; Zhang, Hengmin; Mlynarchik, Andrew K.; Inoue, Keisuke; Mizuno, Ken; Aikawa, Masanori

    2015-01-01

    Objectives Angiopoietin-like protein 2 (ANGPTL2), a recently identified pro-inflammatory cytokine, is mainly secreted from the adipose tissue. This study aimed to explore the role of ANGPTL2 in adipose tissue inflammation and macrophage activation in a mouse model of diabetes. Methodology/Principal Findings Adenovirus mediated lacZ (Ad-LacZ) or human ANGPTL2 (Ad-ANGPTL2) was delivered via tail vein in diabetic db/db mice. Ad-ANGPTL2 treatment for 2 weeks impaired both glucose tolerance and insulin sensitivity as compared to Ad-LacZ treatment. Ad-ANGPTL2 treatment significantly induced pro-inflammatory gene expression in white adipose tissue. We also isolated stromal vascular fraction from epididymal fat pad and analyzed adipose tissue macrophage and T lymphocyte populations by flow cytometry. Ad-ANGPTL2 treated mice had more adipose tissue macrophages (F4/80+CD11b+) and a larger M1 macrophage subpopulation (F4/80+CD11b+CD11c+). Moreover, Ad-ANGPTL2 treatment increased a CD8-positive T cell population in adipose tissue, which preceded increased macrophage accumulation. Consistent with our in vivo results, recombinant human ANGPTL2 protein treatment increased mRNA levels of pro-inflammatory gene products and production of TNF-α protein in the human macrophage-like cell line THP-1. Furthermore, Ad-ANGPTL2 treatment induced lipid accumulation and increased fatty acid synthesis, lipid metabolism related gene expression in mouse liver. Conclusion ANGPTL2 treatment promotes macrophage accumulation and activation. These results suggest potential mechanisms for insulin resistance. PMID:26132105

  17. Epidermal growth factor treatment of the adult brain subventricular zone leads to focal microglia/macrophage accumulation and angiogenesis.

    Science.gov (United States)

    Lindberg, Olle R; Brederlau, Anke; Kuhn, H Georg

    2014-04-01

    One of the major components of the subventricular zone (SVZ) neurogenic niche is the specialized vasculature. The SVZ vasculature is thought to be important in regulating progenitor cell proliferation and migration. Epidermal growth factor (EGF) is a mitogen with a wide range of effects. When stem and progenitor cells in the rat SVZ are treated with EGF, using intracerebroventricular infusion, dysplastic polyps are formed. Upon extended infusion, blood vessels are recruited into the polyps. In the current study we demonstrate how polyps develop through distinct stages leading up to angiogenesis. As polyps progress, microglia/macrophages accumulate in the polyp core concurrent with increasing cell death. Both microglia/macrophage accumulation and cell death peak during angiogenesis and subsequently decline following polyp vascularization. This model of inducible angiogenesis in the SVZ neurogenic niche suggests involvement of microglia/macrophages in acquired angiogenesis and can be used in detail to study angiogenesis in the adult brain.

  18. Activation of PPARγ does not contribute to macrophage ABCA1 expression and ABCA1-mediated cholesterol efflux to apoAI.

    Science.gov (United States)

    Jiang, Meixiu; Li, Xiaoju

    2017-01-22

    Activation of macrophage ABCA1/G1 expression and cholesterol efflux is believed one of the mechanisms by which PPARγ inhibits atherosclerosis. PPARγ can also activate CD36 expression, a receptor for oxLDL, which may supply LXR ligands to activate LXR-ABCA1/G1 pathways. However, the controversial effects of PPARγ on ABCA1 expression have been reported. In this study, we used peritoneal macrophages isolated from wild type and CD36 deficient (CD36(-/-)) mice to clarify if PPARγ ligands can influence ABCA1 expression by CD36 function. We found that CD36 deficiency had no effect on cholesterol efflux and ABCA1/ABCG1 expression at basal levels. In both cell types, PPARγ ligands (15d-PGJ2, troglitazone and pioglitazone) reduced ABCA1 expression and ABCA1-mediated cholesterol efflux to apoAI, with most by troglitazone. LXR ligand-induced ABCA1 expression and cholesterol efflux was attenuated by PPARγ ligands. Associated with decreased ABCA1 protein levels, ABCA1 mRNA and promoter activity were reduced by PPARγ ligands. Furthermore, high expressing PPARγ reduced ABCA1 expression and LXR-activated ABCA1 promoter in a CD36-independent manner. In contrast, ABCG1 expression was induced by PPARγ ligands while inhibited by PPARγ inactivation. Taken together, our study suggests that enhancement of macrophage cholesterol metabolism by PPARγ is not contributed by activating ABCA1 expression and ABCA1-mediated cholesterol efflux to apoAI, which is not involved by CD36 expression either. Copyright © 2016 Elsevier Inc. All rights reserved.

  19. Cilostazol inhibits accumulation of triglyceride in aorta and platelet aggregation in cholesterol-fed rabbits.

    Directory of Open Access Journals (Sweden)

    Hideki Ito

    Full Text Available Cilostazol is clinically used for the treatment of ischemic symptoms in patients with chronic peripheral arterial obstruction and for the secondary prevention of brain infarction. Recently, it has been reported that cilostazol has preventive effects on atherogenesis and decreased serum triglyceride in rodent models. There are, however, few reports on the evaluation of cilostazol using atherosclerotic rabbits, which have similar lipid metabolism to humans, and are used for investigating the lipid content in aorta and platelet aggregation under conditions of hyperlipidemia. Therefore, we evaluated the effect of cilostazol on the atherosclerosis and platelet aggregation in rabbits fed a normal diet or a cholesterol-containing diet supplemented with or without cilostazol. We evaluated the effects of cilostazol on the atherogenesis by measuring serum and aortic lipid content, and the lesion area after a 10-week treatment and the effect on platelet aggregation after 1- and 10-week treatment. From the lipid analyses, cilostazol significantly reduced the total cholesterol, triglyceride and phospholipids in serum, and moreover, the triglyceride content in the atherosclerotic aorta. Cilostazol significantly reduced the intimal atherosclerotic area. Platelet aggregation was enhanced in cholesterol-fed rabbits. Cilostazol significantly inhibited the platelet aggregation in rabbits fed both a normal diet and a high cholesterol diet. Cilostazol showed anti-atherosclerotic and anti-platelet effects in cholesterol-fed rabbits possibly due to the improvement of lipid metabolism and the attenuation of platelet activation. The results suggest that cilostazol is useful for prevention and treatment of atherothrombotic diseases with the lipid abnormalities.

  20. Curcumin inhibits cellular cholesterol accumulation by regulating SREBP-1/caveolin-1 signaling pathway in vascular smooth muscle cells

    Institute of Scientific and Technical Information of China (English)

    Hao-yu YUAN; Shuang-yu KUANG; Xing ZHENG; Hong-yan LING; Yun-bo YANG; Peng-ke YAN; Kai LI; Duan-fang LIAO

    2008-01-01

    Aim: To investigate the protective effect and the possible mechanism of curcumin on anti-atherosclerosis. Methods: Morphological changes of atherosclerotic le-sions taken from apoE knockout (apoE-/-) mice were determined by hematoxylin-eosin staining. Intracellular lipid droplets and lipid levels were assayed by oil red O staining and HPLC. The protein expression of caveolin-1 was quantified by West-ern blotting. Translocation and the expression of sterol response element-bind-ing protein-1 (SREBP-1) were indirectly detected by an immunofluorescence analysis. Results: The administration of 20 mg.kg-1.d-1 curcumin to apoE-/1 mice for 4 months induced a 50% reduction of atherosclerotic lesions and yielded a 5-fold increase in the caveolin-1 expression level as compared to the model group. Rat vascular smooth muscle cells (VSMC) pretreated with 50 mg.L-1 ox-lipid den-sity lipoprotein(ox-LDL) for 48 h increased cellular lipid contents, and stimulated SREBP-1 translocation, but decreased the caveolin-1 expression level. Lipid-loaded cells exposed to curcumin at various concentrations (12.5, 25, and 50 μmol.L-1) for different durations (0, 6, 12, 24, and 48 h) significantly diminished the number and area of cellular lipid droplets, total cholesterol, cholesterol ester, and free choles-terol accompanying the elevation of the caveolin-1 expression level (approximately 3-fold); the translocation of SREBP-1 from the cytoplasm to the nucleus was inhibited compared with the models. Lipid-loaded VSMC exposed to N-acetyl-Leu-Leu-norleucinal, a SREBP-1 protease inhibitor, showed increased nuclear trans-location of SREBP-1, reduced caveolin-1 expression level, and upregulated cellu-lar lipid levels. Conclusion: Curcumin inhibits ox-LDL-induced cholesterol accu-mulation in cultured VSMC through increasing the caveolin-1 expression via the inhibition of nuclear translocation of SREBP-1.

  1. Restoration of IFNγR subunit assembly, IFNγ signaling and parasite clearance in Leishmania donovani infected macrophages: role of membrane cholesterol.

    Directory of Open Access Journals (Sweden)

    Subha Sen

    2011-09-01

    Full Text Available Despite the presence of significant levels of systemic Interferon gamma (IFNγ, the host protective cytokine, Kala-azar patients display high parasite load with downregulated IFNγ signaling in Leishmania donovani (LD infected macrophages (LD-MØs; the cause of such aberrant phenomenon is unknown. Here we reveal for the first time the mechanistic basis of impaired IFNγ signaling in parasitized murine macrophages. Our study clearly shows that in LD-MØs IFNγ receptor (IFNγR expression and their ligand-affinity remained unaltered. The intracellular parasites did not pose any generalized defect in LD-MØs as IL-10 mediated signal transducer and activator of transcription 3 (STAT3 phosphorylation remained unaltered with respect to normal. Previously, we showed that LD-MØs are more fluid than normal MØs due to quenching of membrane cholesterol. The decreased rigidity in LD-MØs was not due to parasite derived lipophosphoglycan (LPG because purified LPG failed to alter fluidity in normal MØs. IFNγR subunit 1 (IFNγR1 and subunit 2 (IFNγR2 colocalize in raft upon IFNγ stimulation of normal MØs, but this was absent in LD-MØs. Oddly enough, such association of IFNγR1 and IFNγR2 could be restored upon liposomal delivery of cholesterol as evident from the fluorescence resonance energy transfer (FRET experiment and co-immunoprecipitation studies. Furthermore, liposomal cholesterol treatment together with IFNγ allowed reassociation of signaling assembly (phospho-JAK1, JAK2 and STAT1 in LD-MØs, appropriate signaling, and subsequent parasite killing. This effect was cholesterol specific because cholesterol analogue 4-cholestene-3-one failed to restore the response. The presence of cholesterol binding motifs [(L/V-X(1-5-Y-X(1-5-(R/K] in the transmembrane domain of IFNγR1 was also noted. The interaction of peptides representing this motif of IFNγR1 was studied with cholesterol-liposome and analogue-liposome with difference of two orders of

  2. Enhanced fatty acid oxidation in adipocytes and macrophages reduces lipid-induced triglyceride accumulation and inflammation.

    Science.gov (United States)

    Malandrino, Maria Ida; Fucho, Raquel; Weber, Minéia; Calderon-Dominguez, María; Mir, Joan Francesc; Valcarcel, Lorea; Escoté, Xavier; Gómez-Serrano, María; Peral, Belén; Salvadó, Laia; Fernández-Veledo, Sonia; Casals, Núria; Vázquez-Carrera, Manuel; Villarroya, Francesc; Vendrell, Joan J; Serra, Dolors; Herrero, Laura

    2015-05-01

    Lipid overload in obesity and type 2 diabetes is associated with adipocyte dysfunction, inflammation, macrophage infiltration, and decreased fatty acid oxidation (FAO). Here, we report that the expression of carnitine palmitoyltransferase 1A (CPT1A), the rate-limiting enzyme in mitochondrial FAO, is higher in human adipose tissue macrophages than in adipocytes and that it is differentially expressed in visceral vs. subcutaneous adipose tissue in both an obese and a type 2 diabetes cohort. These observations led us to further investigate the potential role of CPT1A in adipocytes and macrophages. We expressed CPT1AM, a permanently active mutant form of CPT1A, in 3T3-L1 CARΔ1 adipocytes and RAW 264.7 macrophages through adenoviral infection. Enhanced FAO in palmitate-incubated adipocytes and macrophages reduced triglyceride content and inflammation, improved insulin sensitivity in adipocytes, and reduced endoplasmic reticulum stress and ROS damage in macrophages. We conclude that increasing FAO in adipocytes and macrophages improves palmitate-induced derangements. This indicates that enhancing FAO in metabolically relevant cells such as adipocytes and macrophages may be a promising strategy for the treatment of chronic inflammatory pathologies such as obesity and type 2 diabetes.

  3. Kaempferol suppresses lipid accumulation in macrophages through the downregulation of cluster of differentiation 36 and the upregulation of scavenger receptor class B type I and ATP-binding cassette transporters A1 and G1.

    Science.gov (United States)

    Li, Xiu-Ying; Kong, Ling-Xi; Li, Juan; He, Hai-Xia; Zhou, Yuan-Da

    2013-02-01

    The accumulation of foam cells in atherosclerotic lesions is a hallmark of early-stage atherosclerosis. Kaempferol has been shown to inhibit oxidized low-density lipoprotein (oxLDL) uptake by macrophages; however, the underlying molecular mechanisms are not yet fully investigated. In this study, we shown that treatment with kaempferol markedly suppresses oxLDL-induced macrophage foam cell formation, which occurs due to a decrease in lipid accumulation and an increase in cholesterol efflux from THP-1-derived macrophages. Additionally, the kaempferol treatment of macrophages led to the downregulation of cluster of differentiation 36 (CD36) protein levels, the upregulation of ATP-binding cassette (ABC) transporter A1 (ABCA1), scavenger receptor class B type I (SR-BI) and ABCG1 protein levels, while no effects on scavenger receptor A (SR-A) expression were observed. Kaempferol had similar effects on the mRNA and protein expression of ABCA1, SR-BI, SR-A, CD36 and ABCG1. The reduced CD36 expression following kaempferol treatment involved the inhibition of c-Jun-activator protein-1 (AP-1) nuclear translocation. The inhibition of AP-1 using the inhibitor, SP600125, confirmed this involvement, as the AP-1 inhibition significantly augmented the kaempferol-induced reduction in CD36 expression. Accordingly, the kaempferol-mediated suppression of lipid accumulation in macrophages was also augmented by SP600125. The increased expression of ABCA1, SR-BI and ABCG1 following kaempferol treatment was accompanied by the enhanced protein expression of heme oxygenase-1 (HO-1). This increase was reversed following the knockdown of the HO-1 gene using small hairpin RNA (shRNA). Moreover, the kaempferol-mediated attenuation of lipid accumulation and the promotion of cholesterol efflux was also inhibited by HO-1 shRNA. In conclusion, the c-Jun-AP‑1-dependent downregulation of CD36 and the HO-1-dependent upregulation of ABCG1, SR-BI and ABCA1 may mediate the beneficial effects of

  4. Epidermal Growth Factor Treatment of the Adult Brain Subventricular Zone Leads to Focal Microglia/Macrophage Accumulation and Angiogenesis

    Directory of Open Access Journals (Sweden)

    Olle R. Lindberg

    2014-04-01

    Full Text Available One of the major components of the subventricular zone (SVZ neurogenic niche is the specialized vasculature. The SVZ vasculature is thought to be important in regulating progenitor cell proliferation and migration. Epidermal growth factor (EGF is a mitogen with a wide range of effects. When stem and progenitor cells in the rat SVZ are treated with EGF, using intracerebroventricular infusion, dysplastic polyps are formed. Upon extended infusion, blood vessels are recruited into the polyps. In the current study we demonstrate how polyps develop through distinct stages leading up to angiogenesis. As polyps progress, microglia/macrophages accumulate in the polyp core concurrent with increasing cell death. Both microglia/macrophage accumulation and cell death peak during angiogenesis and subsequently decline following polyp vascularization. This model of inducible angiogenesis in the SVZ neurogenic niche suggests involvement of microglia/macrophages in acquired angiogenesis and can be used in detail to study angiogenesis in the adult brain.

  5. The role of mitogen-activated protein kinases and sterol receptor coactivator-1 in TGF-β-regulated expression of genes implicated in macrophage cholesterol uptake

    Science.gov (United States)

    Salter, Rebecca C.; Foka, Pelagia; Davies, Thomas S.; Gallagher, Hayley; Michael, Daryn R.; Ashlin, Tim G.; Ramji, Dipak P.

    2016-01-01

    The anti-atherogenic cytokine TGF-β inhibits macrophage foam cell formation by suppressing the expression of key genes implicated in the uptake of modified lipoproteins. We have previously shown a critical role for p38 MAPK and JNK in the TGF-β-mediated regulation of apolipoprotein E expression in human monocytes. However, the roles of these two MAPK pathways in the control of expression of key genes involved in the uptake of modified lipoproteins in human macrophages is poorly understood and formed the focus of this study. TGF-β activated both p38 MAPK and JNK, and knockdown of p38 MAPK or c-Jun, a key downstream target of JNK action, demonstrated their requirement in the TGF-β-inhibited expression of several key genes implicated in macrophage lipoprotein uptake. The potential role of c-Jun and specific co-activators in the action of TGF-β was investigated further by studies on the lipoprotein lipase gene. c-Jun did not directly interact with the minimal promoter region containing the TGF-β response elements and a combination of transient transfection and knock down assays revealed an important role for SRC-1. These studies provide novel insights into the mechanisms underlying the TGF-β-mediated inhibition of macrophage gene expression associated with the control of cholesterol homeostasis. PMID:27687241

  6. The role of mitogen-activated protein kinases and sterol receptor coactivator-1 in TGF-β-regulated expression of genes implicated in macrophage cholesterol uptake.

    Science.gov (United States)

    Salter, Rebecca C; Foka, Pelagia; Davies, Thomas S; Gallagher, Hayley; Michael, Daryn R; Ashlin, Tim G; Ramji, Dipak P

    2016-09-30

    The anti-atherogenic cytokine TGF-β inhibits macrophage foam cell formation by suppressing the expression of key genes implicated in the uptake of modified lipoproteins. We have previously shown a critical role for p38 MAPK and JNK in the TGF-β-mediated regulation of apolipoprotein E expression in human monocytes. However, the roles of these two MAPK pathways in the control of expression of key genes involved in the uptake of modified lipoproteins in human macrophages is poorly understood and formed the focus of this study. TGF-β activated both p38 MAPK and JNK, and knockdown of p38 MAPK or c-Jun, a key downstream target of JNK action, demonstrated their requirement in the TGF-β-inhibited expression of several key genes implicated in macrophage lipoprotein uptake. The potential role of c-Jun and specific co-activators in the action of TGF-β was investigated further by studies on the lipoprotein lipase gene. c-Jun did not directly interact with the minimal promoter region containing the TGF-β response elements and a combination of transient transfection and knock down assays revealed an important role for SRC-1. These studies provide novel insights into the mechanisms underlying the TGF-β-mediated inhibition of macrophage gene expression associated with the control of cholesterol homeostasis.

  7. Rosiglitazone inhibits expression of acyl-coenzyme A:cholesterol acyltransferase-1 in THP-1 macrophages induced by advanced glycation end-products

    Institute of Scientific and Technical Information of China (English)

    Yang Qihong; Xu Qiang; Zhang Hong; Si Liangyi

    2008-01-01

    Objective: To investigate the effects of rosiglitazone, a synthetic ligand of peroxisome proliferators-activated receptor gamma (PPARγ), on the expression of acyl-coenzyme A: cholesterol acyltransferase-1 (ACAT-1) in phorbol myristate acetate (PMA)-pretreated THP-1 cells after the inducement of advanced glycation end products (AGEs). Methods: After THP-1 cells were cultured in the presence of 0.1 umol/L PMA for 72 h to induce phagocytic differentiation, the obtained THP-1 macrophages were treated with rosiglitazone for 4 h at different concentrations (1,5 or 10 μmol/L) and then exposed to AGEs-modified bovine serum albumin (AGEs-BSA) for 24 h at a concentration of 200 mg/L. Reverse transcription polymerase chain reaction (RT-PCR) and Western blot analysis were performed to detect the mRNA and protein expressions of ACAT-1 respectively. Results: Administration of AGEs-BSA (200 mg/L) into the THP-1 macrophages resulted in up-regulation of ACAT-1 at mRNA and protein levels when compared with the expressions in macrophages incubated with serum-free RPM11640. Pretreatment of rosiglitazone inhibited significantly the increased expression of ACAT-1 induced by AGEs-BSA in a concentration-dependent manner. Conclusion: PPARγ activation by rosiglitazone down-regulates ACAT-1 expression induced by AGEs in THP-1 macrophages, which might provide a new way for treating atherogenesis in diabetic patients.

  8. Curcumin Supplementation Decreases Intestinal Adiposity Accumulation, Serum Cholesterol Alterations, and Oxidative Stress in Ovariectomized Rats

    Directory of Open Access Journals (Sweden)

    Maurilio da Silva Morrone

    2016-01-01

    Full Text Available The aim of this study was to investigate the potential of curcumin oral supplementation (50 and 100 mg/Kg/day, for 30 days in circumventing menopause-associated oxidative stress and lipid profile dysfunctions in a rat ovariectomy (OVX model. Female Wistar rats were operated and randomly divided into either sham-operated or OVX groups. Sham-operated group (n=8 and one OVX group (n=11 were treated with vehicle (refined olive oil, and the other two OVX groups received curcumin at 50 or 100 mg/Kg/day doses (n=8/group. OVX vehicle-treated animals presented a higher deposition of intestinal adipose tissue as well as increased serum levels of IL-6, LDL, and total cholesterol when compared to sham-operated rats. In addition, several oxidative stress markers in serum, blood, and liver (such as TBARS, carbonyl, reduced-sulphydryl, and nonenzymatic antioxidant defenses were altered toward a prooxidant status by OVX. Interestingly, curcumin supplementation attenuated most of these parameters to sham comparable values. Thus, the herein presented results show that curcumin may be useful to ameliorate lipid metabolism alterations and oxidative damage associated with hormone deprivation in menopause.

  9. Curcumin Supplementation Decreases Intestinal Adiposity Accumulation, Serum Cholesterol Alterations, and Oxidative Stress in Ovariectomized Rats.

    Science.gov (United States)

    Morrone, Maurilio da Silva; Schnorr, Carlos Eduardo; Behr, Guilherme Antônio; Gasparotto, Juciano; Bortolin, Rafael Calixto; da Boit Martinello, Katia; Saldanha Henkin, Bernardo; Rabello, Thallita Kelly; Zanotto-Filho, Alfeu; Gelain, Daniel Pens; Moreira, José Cláudio Fonseca

    2016-01-01

    The aim of this study was to investigate the potential of curcumin oral supplementation (50 and 100 mg/Kg/day, for 30 days) in circumventing menopause-associated oxidative stress and lipid profile dysfunctions in a rat ovariectomy (OVX) model. Female Wistar rats were operated and randomly divided into either sham-operated or OVX groups. Sham-operated group (n = 8) and one OVX group (n = 11) were treated with vehicle (refined olive oil), and the other two OVX groups received curcumin at 50 or 100 mg/Kg/day doses (n = 8/group). OVX vehicle-treated animals presented a higher deposition of intestinal adipose tissue as well as increased serum levels of IL-6, LDL, and total cholesterol when compared to sham-operated rats. In addition, several oxidative stress markers in serum, blood, and liver (such as TBARS, carbonyl, reduced-sulphydryl, and nonenzymatic antioxidant defenses) were altered toward a prooxidant status by OVX. Interestingly, curcumin supplementation attenuated most of these parameters to sham comparable values. Thus, the herein presented results show that curcumin may be useful to ameliorate lipid metabolism alterations and oxidative damage associated with hormone deprivation in menopause.

  10. NO-1886 suppresses diet-induced insulin resistance and cholesterol accumulation through STAT5-dependent upregulation of IGF1 and CYP7A1.

    Science.gov (United States)

    Li, Qinkai; Yin, Weidong; Cai, Manbo; Liu, Yi; Hou, Hongjie; Shen, Qingyun; Zhang, Chi; Xiao, Junxia; Hu, Xiaobo; Wu, Qishisan; Funaki, Makoto; Nakaya, Yutaka

    2010-01-01

    Insulin resistance and dyslipidemia are both considered to be risk factors for metabolic syndrome. Low levels of IGF1 are associated with insulin resistance. Elevation of low-density lipoprotein cholesterol (LDL-C) concomitant with depression of high-density lipoprotein cholesterol (HDL-C) increase the risk of obesity and type 2 diabetes mellitus (T2DM). Liver secretes IGF1 and catabolizes cholesterol regulated by the rate-limiting enzyme of bile acid synthesis from cholesterol 7alpha-hydroxylase (CYP7A1). NO-1886, a chemically synthesized lipoprotein lipase activator, suppresses diet-induced insulin resistance with the improvement of HDL-C. The goal of the present study is to evaluate whether NO-1886 upregulates IGF1 and CYP7A1 to benefit glucose and cholesterol metabolism. By using human hepatoma cell lines (HepG2 cells) as an in vitro model, we found that NO-1886 promoted IGF1 secretion and CYP7A1 expression through the activation of signal transducer and activator of transcription 5 (STAT5). Pretreatment of cells with AG 490, the inhibitor of STAT pathway, completely abolished NO-1886-induced IGF1 secretion and CYP7A1 expression. Studies performed in Chinese Bama minipigs pointed out an augmentation of plasma IGF1 elicited by a single dose administration of NO-1886. Long-term supplementation with NO-1886 recovered hyperinsulinemia and low plasma levels of IGF1 suppressed LDL-C and facilitated reverse cholesterol transport by decreasing hepatic cholesterol accumulation through increasing CYP7A1 expression in high-fat/high-sucrose/high-cholesterol diet minipigs. These findings indicate that NO-1886 upregulates IGF1 secretion and CYP7A1 expression to improve insulin resistance and hepatic cholesterol accumulation, which may represent an alternative therapeutic avenue of NO-1886 for T2DM and metabolic syndrome.

  11. Suppression of nitric oxide production in mouse macrophages by soybean flavonoids accumulated in response to nitroprusside and fungal elicitation

    Directory of Open Access Journals (Sweden)

    Tamashiro Wirla MSC

    2004-04-01

    Full Text Available Abstract Background The anti-inflammatory properties of some flavonoids have been attributed to their ability to inhibit the production of NO by activated macrophages. Soybean cotyledons accumulate certain flavonoids following elicitation with an extract of the fungal pathogen Diaporthe phaseolorum f. sp. meridionalis (Dpm. Sodium nitroprusside (SNP, a nitric oxide donor, can substitute for Dpm in inducing flavonoid production. In this study, we investigated the effect of flavonoid-containing diffusates obtained from Dpm- and SNP-elicited soybean cotyledons on NO production by lipopolysaccharide (LPS- and LPS plus interferon-γ (IFNγ-activated murine macrophages. Results Significant inhibition of NO production, measured as nitrite formation, was observed when macrophages were activated in the presence of soybean diffusates from Dpm- or SNP-elicited cotyledons. This inhibition was dependent on the duration of exposure to the elicitor. Daidzein, genistein, luteolin and apigenin, the main flavonoids present in diffusates of elicited cotyledons, suppressed the NO production by LPS + IFNγ activated macrophages in a concentration-dependent manner, with IC50 values of 81.4 μM, 34.5 μM, 38.6 μM and 10.4 μM respectively. For macrophages activated with LPS alone, the IC50 values were 40.0 μM, 16.6 μM, 10.4 μM and 2.8 μM, respectively. Western blot analysis showed that iNOS expression was not affected by daidzein, was reduced by genistein, and was abolished by apigenin, luteolin and Dpm- and SNP-soybean diffusates at concentrations that significantly inhibited NO production by activated macrophages. Conclusions These results suggest that the suppressive effect of flavonoids on iNOS expression could account for the potent inhibitory effect of Dpm- and SNP-diffusates on NO production by activated macrophages. Since the physiological concentration of flavonoids in plants is normally low, the treatment of soybean tissues with SNP may provide a simple

  12. Mycobacterium tuberculosis uses host triacylglycerol to accumulate lipid droplets and acquires a dormancy-like phenotype in lipid-loaded macrophages.

    Science.gov (United States)

    Daniel, Jaiyanth; Maamar, Hédia; Deb, Chirajyoti; Sirakova, Tatiana D; Kolattukudy, Pappachan E

    2011-06-01

    Two billion people are latently infected with Mycobacterium tuberculosis (Mtb). Mtb-infected macrophages are likely to be sequestered inside the hypoxic environments of the granuloma and differentiate into lipid-loaded macrophages that contain triacylglycerol (TAG)-filled lipid droplets which may provide a fatty acid-rich host environment for Mtb. We report here that human peripheral blood monocyte-derived macrophages and THP-1 derived macrophages incubated under hypoxia accumulate Oil Red O-staining lipid droplets containing TAG. Inside such hypoxic, lipid-loaded macrophages, nearly half the Mtb population developed phenotypic tolerance to isoniazid, lost acid-fast staining and accumulated intracellular lipid droplets. Dual-isotope labeling of macrophage TAG revealed that Mtb inside the lipid-loaded macrophages imports fatty acids derived from host TAG and incorporates them intact into Mtb TAG. The fatty acid composition of host and Mtb TAG were nearly identical suggesting that Mtb utilizes host TAG to accumulate intracellular TAG. Utilization of host TAG by Mtb for lipid droplet synthesis was confirmed when fluorescent fatty acid-labeled host TAG was utilized to accumulate fluorescent lipid droplets inside the pathogen. Deletion of the Mtb triacylglycerol synthase 1 (tgs1) gene resulted in a drastic decrease but not a complete loss in both radiolabeled and fluorescent TAG accumulation by Mtb suggesting that the TAG that accumulates within Mtb is generated mainly by the incorporation of fatty acids released from host TAG. We show direct evidence for the utilization of the fatty acids from host TAG for lipid metabolism inside Mtb. Taqman real-time PCR measurements revealed that the mycobacterial genes dosR, hspX, icl1, tgs1 and lipY were up-regulated in Mtb within hypoxic lipid loaded macrophages along with other Mtb genes known to be associated with dormancy and lipid metabolism.

  13. Hazelnut Oil Administration Reduces Aortic Cholesterol Accumulation and Lipid Peroxides in the Plasma, Liver, and Aorta of Rabbits Fed a High-cholesterol Diet

    National Research Council Canada - National Science Library

    HATIPOGLU, Aydan; KANBAGLI, Öznur; BALKAN, Jale; KÜÇÜK, Mutlu; ÇEVIKBAS, Ugur; AYKAÇ-TOKER, Gülçin; BERKKAN, Hakan; UYSAL, Müjdat

    2004-01-01

    Hazelnut oil (HO) is rich in monounsaturated fatty acids and antioxidants. We wanted to investigate the effect of HO on lipid levels and prooxidant-antioxidant status in rabbits fed a high-cholesterol (HC) diet...

  14. Linoleic acid suppresses cholesterol efflux and ATP-binding cassette transporters in murine bone marrow-derived macrophages

    Science.gov (United States)

    Individuals with type 2 diabetes mellitus (T2DM) are at increased risk of developing cardiovascular disease (CVD), possibly associated with elevated plasma free fatty acid concentrations. Paradoxically, evidence suggests that unsaturated, compared to saturated fatty acids, suppress macrophage chole...

  15. Pranlukast reduces neutrophil but not macrophage/microglial accumulation in brain after focal cerebral ischemia in mice

    Institute of Scientific and Technical Information of China (English)

    Li-sheng CHU; Er-qing WEI; Guo-liang YU; San-hua FANG; Yu ZHOU; Meng-ling WANG; Wei-ping ZHANG

    2006-01-01

    Aim:To determine whether pranlukast.a cysteinyl leukotriene receptor-1 antagonist,exerts an anti-inflammatory effect on focal cerebral ischemia in mice.Methods:Focal cerebral ischemia in mice was induced by permanent middle cerebral artery occlusion(MCAO).In addition to neurological deficits,infarct volume,degenerated neurons and endogenous IgG exudation,we detected accumulation of neutrophils and macrophage/microglia in the ischemic brain tissue 72 h after MCAO.Pranlukast was iP injected 30 min before and after MCAO.Results:Pranlukast significantly attenuated neurological deficits,infarct volume,neuron degeneration and IgG exudation.Importantly,pranlukast(0.01 and 0.1 mg/kg) inhibited myeloperoxidase-positive neutrophil,but not CDllb-positive macrophage/microglial accumulation in the ischemic cortical tissue.Conclusion:Pranlukast exerts an anti-inflammatory effect on focal cerebral ischemia in the subacute phase that is limited to neutrophil recruitment through the disrupted blood-brain barrier.

  16. Ly6Chi monocyte recruitment is responsible for Th2 associated host-protective macrophage accumulation in liver inflammation due to schistosomiasis.

    Directory of Open Access Journals (Sweden)

    Marcia Nascimento

    2014-08-01

    Full Text Available Accumulation of M2 macrophages in the liver, within the context of a strong Th2 response, is a hallmark of infection with the parasitic helminth, Schistosoma mansoni, but the origin of these cells is unclear. To explore this, we examined the relatedness of macrophages to monocytes in this setting. Our data show that both monocyte-derived and resident macrophages are engaged in the response to infection. Infection caused CCR2-dependent increases in numbers of Ly6Chi monocytes in blood and liver and of CX3CR1+ macrophages in diseased liver. Ly6Chi monocytes recovered from liver had the potential to differentiate into macrophages when cultured with M-CSF. Using pulse chase BrdU labeling, we found that most hepatic macrophages in infected mice arose from monocytes. Consistent with this, deletion of monocytes led to the loss of a subpopulation of hepatic CD11chi macrophages that was present in infected but not naïve mice. This was accompanied by a reduction in the size of egg-associated granulomas and significantly exacerbated disease. In addition to the involvement of monocytes and monocyte-derived macrophages in hepatic inflammation due to infection, we observed increased incorporation of BrdU and expression of Ki67 and MHC II in resident macrophages, indicating that these cells are participating in the response. Expression of both M2 and M1 marker genes was increased in liver from infected vs. naive mice. The M2 fingerprint in the liver was not accounted for by a single cell type, but rather reflected expression of M2 genes by various cells including macrophages, neutrophils, eosinophils and monocytes. Our data point to monocyte recruitment as the dominant process for increasing macrophage cell numbers in the liver during schistosomiasis.

  17. Cholesteryl ester hydrolase activity is abolished in HSL-/- macrophages but unchanged in macrophages lacking KIAA1363.

    Science.gov (United States)

    Buchebner, Marlene; Pfeifer, Thomas; Rathke, Nora; Chandak, Prakash G; Lass, Achim; Schreiber, Renate; Kratzer, Adelheid; Zimmermann, Robert; Sattler, Wolfgang; Koefeler, Harald; Fröhlich, Eleonore; Kostner, Gerhard M; Birner-Gruenberger, Ruth; Chiang, Kyle P; Haemmerle, Guenter; Zechner, Rudolf; Levak-Frank, Sanja; Cravatt, Benjamin; Kratky, Dagmar

    2010-10-01

    Cholesteryl ester (CE) accumulation in macrophages represents a crucial event during foam cell formation, a hallmark of atherogenesis. Here we investigated the role of two previously described CE hydrolases, hormone-sensitive lipase (HSL) and KIAA1363, in macrophage CE hydrolysis. HSL and KIAA1363 exhibited marked differences in their abilities to hydrolyze CE, triacylglycerol (TG), diacylglycerol (DG), and 2-acetyl monoalkylglycerol ether (AcMAGE), a precursor for biosynthesis of platelet-activating factor (PAF). HSL efficiently cleaved all four substrates, whereas KIAA1363 hydrolyzed only AcMAGE. This contradicts previous studies suggesting that KIAA1363 is a neutral CE hydrolase. Macrophages of KIAA1363(-/-) and wild-type mice exhibited identical neutral CE hydrolase activity, which was almost abolished in tissues and macrophages of HSL(-/-) mice. Conversely, AcMAGE hydrolase activity was diminished in macrophages and some tissues of KIAA1363(-/-) but unchanged in HSL(-/-) mice. CE turnover was unaffected in macrophages lacking KIAA1363 and HSL, whereas cAMP-dependent cholesterol efflux was influenced by HSL but not by KIAA1363. Despite decreased CE hydrolase activities, HSL(-/-) macrophages exhibited CE accumulation similar to wild-type (WT) macrophages. We conclude that additional enzymes must exist that cooperate with HSL to regulate CE levels in macrophages. KIAA1363 affects AcMAGE hydrolase activity but is of minor importance as a direct CE hydrolase in macrophages.

  18. Attenuated Pik3r1 Expression Prevents Insulin Resistance and Adipose Tissue Macrophage Accumulation in Diet-Induced Obese Mice

    Science.gov (United States)

    McCurdy, Carrie E.; Schenk, Simon; Holliday, Michael J.; Philp, Andrew; Houck, Julie A.; Patsouris, David; MacLean, Paul S.; Majka, Susan M.; Klemm, Dwight J.; Friedman, Jacob E.

    2012-01-01

    Obese white adipose tissue (AT) is characterized by large-scale infiltration of proinflammatory macrophages, in parallel with systemic insulin resistance; however, the cellular stimulus that initiates this signaling cascade and chemokine release is still unknown. The objective of this study was to determine the role of the phosphoinositide 3-kinase (PI3K) regulatory subunits on AT macrophage (ATM) infiltration in obesity. Here, we find that the Pik3r1 regulatory subunits (i.e., p85α/p55α/p50α) are highly induced in AT from high-fat diet–fed obese mice, concurrent with insulin resistance. Global heterozygous deletion of the Pik3r1 regulatory subunits (αHZ), but not knockout of Pik3r2 (p85β), preserves whole-body, AT, and skeletal muscle insulin sensitivity, despite severe obesity. Moreover, ATM accumulation, proinflammatory gene expression, and ex vivo chemokine secretion in obese αHZ mice are markedly reduced despite endoplasmic reticulum (ER) stress, hypoxia, adipocyte hypertrophy, and Jun NH2-terminal kinase activation. Furthermore, bone marrow transplant studies reveal that these improvements in obese αHZ mice are independent of reduced Pik3r1 expression in the hematopoietic compartment. Taken together, these studies demonstrate that Pik3r1 expression plays a critical role in mediating AT insulin sensitivity and, more so, suggest that reduced PI3K activity is a key step in the initiation and propagation of the inflammatory response in obese AT. PMID:22698915

  19. Effect of macrophage-derived mouse ApoE, human ApoE3-Leiden, and human ApoE2 (Arg158→Cys) on cholesterol levels and atherosclerosis in ApoE- deficient mice

    NARCIS (Netherlands)

    Eck, M. van; Herijgers, N.; Dijk, K.W. van; Havekes, L.M.; Hofker, M.H.; Groot, P.H.E.; Berkel, T.J.C. van

    2000-01-01

    The effect of monocyte/macrophage-derived wild-type mouse apolipoprotein E (apoE), human apoE3-Leiden, and human apoE2 on serum cholesterol levels and the development of atherosclerosis in apoE-deficient (apoe-/-) mice was investigated by using bone marrow transplantation (BMT). At 4 weeks after

  20. Genetic deletion of low density lipoprotein receptor impairs sterol-induced mouse macrophage ABCA1 expression. A new SREBP1-dependent mechanism.

    Science.gov (United States)

    Zhou, Xiaoye; He, Wei; Huang, Zhiping; Gotto, Antonio M; Hajjar, David P; Han, Jihong

    2008-01-25

    Low density lipoprotein receptor (LDLR) mutations cause familial hypercholesterolemia and early atherosclerosis. ABCA1 facilitates free cholesterol efflux from peripheral tissues. We investigated the effects of LDLR deletion (LDLR(-/-)) on ABCA1 expression. LDLR(-/-) macrophages had reduced basal levels of ABCA1, ABCG1, and cholesterol efflux. A high fat diet increased cholesterol in LDLR(-/-) macrophages but not wild type cells. A liver X receptor (LXR) agonist induced expression of ABCA1, ABCG1, and cholesterol efflux in both LDLR(-/-) and wild type macrophages, whereas expression of LXRalpha or LXRbeta was similar. Interestingly, oxidized LDL induced more ABCA1 in wild type macrophages than LDLR(-/-) cells. LDL induced ABCA1 expression in wild type cells but inhibited it in LDLR(-/-) macrophages in a concentration-dependent manner. However, lipoproteins regulated ABCG1 expression similarly in LDLR(-/-) and wild type macrophages. Cholesterol or oxysterols induced ABCA1 expression in wild type macrophages but had little or inhibitory effects on ABCA1 expression in LDLR(-/-) macrophages. Active sterol regulatory element-binding protein 1a (SREBP1a) inhibited ABCA1 promoter activity in an LXRE-dependent manner and decreased both macrophage ABCA1 expression and cholesterol efflux. Expression of ABCA1 in animal tissues was inversely correlated to active SREBP1. Oxysterols inactivated SREBP1 in wild type macrophages but not in LDLR(-/-) cells. Oxysterol synergized with nonsteroid LXR ligand induced ABCA1 expression in wild type macrophages but blocked induction in LDLR(-/-) cells. Taken together, our studies suggest that LDLR is critical in the regulation of cholesterol efflux and ABCA1 expression in macrophage. Lack of the LDLR impairs sterol-induced macrophage ABCA1 expression by a sterol regulatory element-binding protein 1-dependent mechanism that can result in reduced cholesterol efflux and lipid accumulation in macrophages under hypercholesterolemic conditions.

  1. Static pressure accelerates ox-LDL-induced cholesterol accumulation via SREBP-1-mediated caveolin-1 downregulation in cultured vascular smooth muscle cells

    Energy Technology Data Exchange (ETDEWEB)

    Luo, Di-xian, E-mail: luodixian_2@163.com [Department of Pharmacology, School of Pharmaceutics, Central South University, Changsha 410083, Hunan (China); Institute of Pharmacy and Pharmacology, College of Science and Technology, University of South China, Hengyang 421001, Hunan (China); First People' s Hospital of Chenzhou City, Chenzhou 423000, Hunan (China); Xia, Cheng-lai [Institute of Pharmacy and Pharmacology, College of Science and Technology, University of South China, Hengyang 421001, Hunan (China); Department of Pharmacy, Third Affiliated Hospital Medical College of Guangzhou, Guangzhou 510150, Guangdong (China); Li, Jun-mu [Institute of Pharmacy and Pharmacology, College of Science and Technology, University of South China, Hengyang 421001, Hunan (China); Xiong, Yan [Department of Pharmacology, School of Pharmaceutics, Central South University, Changsha 410083, Hunan (China); Yuan, Hao-yu [Institute of Pharmacy and Pharmacology, College of Science and Technology, University of South China, Hengyang 421001, Hunan (China); Lusong Center for Disease Control and Prevention, Zhuzhou 412000, Hunan (China); TANG, Zhen-Wang; Zeng, Yixin [Institute of Pharmacy and Pharmacology, College of Science and Technology, University of South China, Hengyang 421001, Hunan (China); Liao, Duan-fang, E-mail: dfliao66@yahoo.com.cn [Institute of Pharmacy and Pharmacology, College of Science and Technology, University of South China, Hengyang 421001, Hunan (China); Department of Traditional Chinese Diagnostics, School of Pharmacy, Hunan University of Chinese Medicine, Changsha 420108, Hunan (China)

    2010-12-03

    Research highlights: {yields} Vertical static pressure accelerates ox-LDL-induced cholesterol accumulation in cultured vascular smooth muscle cells. {yields} Static pressure induces SREBP-1 activation. {yields} Static pressure downregulates the expressions of caveolin-1 by activating SREBP-1. {yields} Static pressure also downregulates the transcription of ABCA1 by activating SREBP-1. {yields} Static pressure increases ox-LDL-induced cholesterol accumulation by SREBP-1-mediated caveolin-1 downregulation in vascular smooth muscle cells cultured in vitro. -- Abstract: Objective: To investigate the effect of static pressure on cholesterol accumulation in vascular smooth muscle cells (VSMCs) and its mechanism. Methods: Rat-derived VSMC cell line A10 treated with 50 mg/L ox-LDL and different static pressures (0, 60, 90, 120, 150, 180 mm Hg) in a custom-made pressure incubator for 48 h. Intracellular lipid droplets and lipid levels were assayed by oil red O staining and HPLC; The mRNA levels of caveolin-1 and ABCA1, the protein levels of caveolin-1 SREBP-1 and mature SREBP-1 were respectively detected by RT-PCR or western blot. ALLN, an inhibitor of SREBP metabolism, was used to elevate SREBP-1 protein level in VSMCs treated with static pressure. Results: Static pressures significantly not only increase intracellular lipid droplets in VSMCs, but also elevate cellular lipid content in a pressure-dependent manner. Intracellular free cholesterol (FC), cholesterol ester (CE), total cholesterol (TC) were respectively increased from 60.5 {+-} 2.8 mg/g, 31.8 {+-} 0.7 mg/g, 92.3 {+-} 2.1 mg/g at atmosphere pressure (ATM, 0 mm Hg) to 150.8 {+-} 9.4 mg/g, 235.9 {+-} 3.0 mg/g, 386.7 {+-} 6.4 mg/g at 180 mm Hg. At the same time, static pressures decrease the mRNA and protein levels of caveolin-1, and induce the activation and nuclear translocation of SREBP-1. ALLN increases the protein level of mature SREBP-1 and decreases caveolin-1 expression, so that cellular lipid levels were

  2. Steroid balance and tissue cholesterol accumulation in germfree and conventional rats fed diets containing saturated and polyunsaturated fats.

    Science.gov (United States)

    Kellogg, T F

    1974-11-01

    Steroid balance studies were conducted on 24 conventional and 12 germfree male rats, 90-120 days old, fed diets containing either 20% safflower or 20% coconut oil. Both germfree and conventional rats fed the safflower oil diets had significantly lower serum cholesterol levels and significantly higher liver cholesterol levels than did the rats fed coconut oil. No significant differences in total fecal neutral sterols, coprostanol, Delta(7)-cholestenol, or total fecal bile acid excretion were seen between dietary groups of rats of either status. There was no evidence of qualitative differences in fecal bile acid excretion as a function of diet. The increased liver cholesterol was in the ester form, with cholesteryl linoleate the largest single component. There was no significant difference in the cholesterol content of the skin, muscle, adipose tissue, or gastrointestinal tract. The significance of a large increase in liver cholesteryl ester, lowered serum cholesterol, and no change in steroid excretion is discussed.

  3. High-density lipoproteincholesterol, reverse cholesterol transport, and cardiovascular risk: a tale of genetics?

    Directory of Open Access Journals (Sweden)

    Giovanni Cimmino

    2013-10-01

    Full Text Available Cholesterol deposition plays a central role in atherogenesis. The accumulation of lipid material is the result of an imbalance between the influx and efflux of cholesterol within the arterial wall. High levels of plasma low-density lipoprotein-cholesterol are considered the major mechanism responsible for the influx and accumulation of cholesterol in the arterial wall, while high-density lipoprotein (HDL- cholesterol seems responsible for its efflux. The mechanism by which cholesterol is removed from extra-hepatic organs and delivered to the liver for its catabolism and excretion is called reverse cholesterol transport (RCT. Epidemiological evidence has associated high levels of HDL-cholesterol/ApoA-I with protection against atherosclerotic disease, but the ultimate mechanism(s responsible for the beneficial effect is not well established. HDLs are synthesized by the liver and small intestine and released to the circulation as a lipid-poor HDL (nascent HDL, mostly formed by ApoA-I and phospholipids. Through their metabolic maturation, HDLs interact with the ABCA1 receptor in the macrophage surface increasing their lipid content by taking phospholipids and cholesterol from macrophages becoming mature HDL. The cholesterol of the HDLs is transported to the liver, via the scavenger receptor class B, type I, for further metabolization and excretion to the intestines in the form of bile acids and cholesterol, completing the process of RCT. It is clear that an inherited mutation or acquired abnormality in any of the key players in RCT mat affect the atherosclerotic process.

  4. Anthocyanins and phenolic acids from a wild blueberry (Vaccinium angustifolium) powder counteract lipid accumulation in THP-1-derived macrophages

    DEFF Research Database (Denmark)

    Del Bo', Cristian; Cao, Yi; Roursgaard, Martin

    2016-01-01

    PURPOSE: Blueberries are a rich source of anthocyanins (ACNs) and phenolic acids (PA), which are hypothesized to protect against development of atherosclerosis. The present study examined the effect of an ACN- and PA-rich fractions, obtained from a wild blueberry powder, on the capacity...... to counteract lipid accumulation in macrophages derived from monocytic THP-1 cells. In addition, we tested the capacity of pure ACNs and their metabolites to alter lipid accumulation. METHODS: THP-1-derived macrophages were incubated with fatty acids (500 μM oleic/palmitic acid, 2:1 ratio) and different...... concentrations (from 0.05 to 10 μg mL(-1)) of ACN- and PA-rich fractions, pure ACN standards (malvidin, delphinidin and cyanidin 3-glucoside), and metabolites (syringic, gallic and protocatechuic acids). Lipid accumulation was quantified with the fluorescent dye Nile red. RESULTS: Lipid accumulation was reduced...

  5. Reverse cholesterol transport: From classical view to new insights

    Institute of Scientific and Technical Information of China (English)

    Astrid; E; van; der; Velde

    2010-01-01

    Cholesterol is of vital importance for the human body. It is a constituent for most biological membranes, it is needed for the formation of bile salts, and it is the pre- cursor for steroid hormones and vitamin D. However, the presence of excess cholesterol in cells, and in particular in macrophages in the arterial vessel wall, might be harmful. The accumulation of cholesterol in arteries can lead to atherosclerosis, and in turn, to other cardiovascular diseases. The route that is primarily thought to be re...

  6. Carbon black nanoparticles promote endothelial activation and lipid accumulation in macrophages independently of intracellular ROS production

    DEFF Research Database (Denmark)

    Cao, Yi; Roursgaard, Martin; Danielsen, Pernille Høgh;

    2014-01-01

    Exposure to nanoparticles (NPs) may cause vascular effects including endothelial dysfunction and foam cell formation, with oxidative stress and inflammation as supposed central mechanisms. We investigated oxidative stress, endothelial dysfunction and lipid accumulation caused by nano-sized carbon...... and WST-1 assays, especially in THP-1 and THP-1a cells. The CB exposure decreased the glutathione (GSH) content in THP-1 and THP-1a cells, whereas GSH was increased in HUVECs. The reactive oxygen species (ROS) production was increased in all cell types after CB exposure. A reduction of the intracellular...

  7. A Helicobacter pylori Homolog of Eukaryotic Flotillin Is Involved in Cholesterol Accumulation, Epithelial Cell Responses and Host Colonization

    Directory of Open Access Journals (Sweden)

    Melanie L. Hutton

    2017-06-01

    Full Text Available The human pathogen Helicobacter pylori acquires cholesterol from membrane raft domains in eukaryotic cells, commonly known as “lipid rafts.” Incorporation of this cholesterol into the H. pylori cell membrane allows the bacterium to avoid clearance by the host immune system and to resist the effects of antibiotics and antimicrobial peptides. The presence of cholesterol in H. pylori bacteria suggested that this pathogen may have cholesterol-enriched domains within its membrane. Consistent with this suggestion, we identified a hypothetical H. pylori protein (HP0248 with homology to the flotillin proteins normally found in the cholesterol-enriched domains of eukaryotic cells. As shown for eukaryotic flotillin proteins, HP0248 was detected in detergent-resistant membrane fractions of H. pylori. Importantly, H. pylori HP0248 mutants contained lower levels of cholesterol than wild-type bacteria (P < 0.01. HP0248 mutant bacteria also exhibited defects in type IV secretion functions, as indicated by reduced IL-8 responses and CagA translocation in epithelial cells (P < 0.05, and were less able to establish a chronic infection in mice than wild-type bacteria (P < 0.05. Thus, we have identified an H. pylori flotillin protein and shown its importance for bacterial virulence. Taken together, the data demonstrate important roles for H. pylori flotillin in host-pathogen interactions. We propose that H. pylori flotillin may be required for the organization of virulence proteins into membrane raft-like structures in this pathogen.

  8. A Helicobacter pylori Homolog of Eukaryotic Flotillin Is Involved in Cholesterol Accumulation, Epithelial Cell Responses and Host Colonization.

    Science.gov (United States)

    Hutton, Melanie L; D'Costa, Kimberley; Rossiter, Amanda E; Wang, Lin; Turner, Lorinda; Steer, David L; Masters, Seth L; Croker, Ben A; Kaparakis-Liaskos, Maria; Ferrero, Richard L

    2017-01-01

    The human pathogen Helicobacter pylori acquires cholesterol from membrane raft domains in eukaryotic cells, commonly known as "lipid rafts." Incorporation of this cholesterol into the H. pylori cell membrane allows the bacterium to avoid clearance by the host immune system and to resist the effects of antibiotics and antimicrobial peptides. The presence of cholesterol in H. pylori bacteria suggested that this pathogen may have cholesterol-enriched domains within its membrane. Consistent with this suggestion, we identified a hypothetical H. pylori protein (HP0248) with homology to the flotillin proteins normally found in the cholesterol-enriched domains of eukaryotic cells. As shown for eukaryotic flotillin proteins, HP0248 was detected in detergent-resistant membrane fractions of H. pylori. Importantly, H. pylori HP0248 mutants contained lower levels of cholesterol than wild-type bacteria (P pylori flotillin protein and shown its importance for bacterial virulence. Taken together, the data demonstrate important roles for H. pylori flotillin in host-pathogen interactions. We propose that H. pylori flotillin may be required for the organization of virulence proteins into membrane raft-like structures in this pathogen.

  9. ER stress is associated with reduced ABCA-1 protein levels in macrophages treated with advanced glycated albumin - reversal by a chemical chaperone.

    Science.gov (United States)

    Castilho, Gabriela; Okuda, Ligia S; Pinto, Raphael S; Iborra, Rodgiro T; Nakandakare, Edna R; Santos, Celio X; Laurindo, Francisco R; Passarelli, Marisa

    2012-07-01

    ATP-binding cassette transporter A1 mediates the export of excess cholesterol from macrophages, contributing to the prevention of atherosclerosis. Advanced glycated albumin (AGE-alb) is prevalent in diabetes mellitus and is associated with the development of atherosclerosis. Independently of changes in ABCA-1 mRNA levels, AGE-alb induces oxidative stress and reduces ABCA-1 protein levels, which leads to macrophage lipid accumulation. These metabolic conditions are known to elicit endoplasmic reticulum (ER) stress. We sought to determine if AGE-alb induces ER stress and unfolded protein response (UPR) in macrophages and how disturbances to the ER could affect ABCA-1 content and cholesterol efflux in macrophages. AGE-alb induced a time-dependent increase in ER stress and UPR markers. ABCA-1 content and cellular cholesterol efflux were reduced by 33% and 47%, respectively, in macrophages treated with AGE-alb, and both were restored by treatment with 4-phenyl butyric acid (a chemical chaperone that alleviates ER stress), but not MG132 (a proteasome inhibitor). Tunicamycin, a classical ER stress inductor, also impaired ABCA-1 expression and cholesterol efflux (showing a decrease of 61% and 82%, respectively), confirming the deleterious effect of ER stress in macrophage cholesterol accumulation. Glycoxidation induces macrophage ER stress, which relates to the reduction in ABCA-1 and in reverse cholesterol transport, endorsing the adverse effect of macrophage ER stress in atherosclerosis. Thus, chemical chaperones that alleviate ER stress may represent a useful tool for the prevention and treatment of atherosclerosis in diabetes.

  10. Angiotensin II-Induced Endothelial Dysfunction is Temporally Linked with Increases in Intereukin-6 and Vascular Macrophage Accumulation

    Directory of Open Access Journals (Sweden)

    Sean P Didion

    2014-10-01

    Full Text Available Angiotensin II (Ang II is associated with vascular hypertrophy, endothelial dysfunction and activation of a number of inflammatory molecules, however the linear events involved in the development of hypertension and endothelial dysfunction produced in response to Ang II are not well defined. The goal of this study was to examine the dose- and temporal-dependent development of endothelial dysfunction in response to Ang II. Blood pressure and responses of carotid arteries were examined in control (C57Bl/6 mice and in mice infused with 50, 100, 200, 400, or 1000 ng/kg/min Ang II for either 14 or 28 Days. Infusion of Ang II was associated with graded and marked increases in systolic blood pressure and plasma Ang II concentrations. While low doses of Ang II (ie, 50 and 100 ng/kg/min had little to no effect on blood pressure or endothelial function, high doses of Ang II (e.g., 1000 ng/kg/min were associated with large increases in arterial pressure and marked impairment of endothelial function. In contrast, intermediate doses of Ang II (200 and 400 ng/kg/min while initially having no effect on systolic blood pressure were associated with significant increases in pressure over time. Despite increasing blood pressure, 200 ng/kg/min had no effect on endothelial function, whereas 400 ng/kg/min produced modest impairment on Day 14 and marked impairment of endothelial function on Day 28. The degree of endothelial dysfunction produced by 400 and 1000 ng/kg/min Ang II was reflective of parallel increases in plasma IL-6 levels and vascular macrophage content, suggesting that increases in arterial blood pressure precede the development of endothelial dysfunction. These findings are important as they demonstrate that along with increases in arterial pressure that increases in IL-6 and vascular macrophage accumulation correlate with the impairment of endothelial function produced by Ang II.

  11. Selected cholesterol biosynthesis inhibitors produce accumulation of the intermediate FF-MAS that targets nucleus and activates LXRα in HepG2 cells.

    Science.gov (United States)

    Gatticchi, Leonardo; Cerra, Bruno; Scarpelli, Paolo; Macchioni, Lara; Sebastiani, Bartolomeo; Gioiello, Antimo; Roberti, Rita

    2017-09-01

    Sterol intermediates of the cholesterol biosynthetic pathway have drawn attention for novel biological activities. Follicular fluid meiosis activating sterol (FF-MAS) is a LXRα ligand and a potential modulator of physiologic processes regulated by nuclear receptors, such as lipid homeostasis and cell proliferation. In this work, we established a model to selectively accumulate FF-MAS in HepG2 cells, by using a combination of the inhibitors AY9944 and 17-hydroxyprogesterone to block C14-sterol reductases and the downstream C4-demethylase complex. We investigated the effects produced by altered levels of cholesterol biosynthesis intermediates, in order to dissect their influence on LXRα signaling. In particular, endogenously accumulated FF-MAS was able to modulate the expression of key genes in cholesterol metabolism, to activate LXRα nuclear signaling resulting in increased lipogenesis, and to inhibit HepG2 cells proliferation. Moreover, a fluorescent ester derivative of FF-MAS localized in nuclear lipid droplets, suggesting a role for these organelles in the storage of signaling lipids interacting with nuclear partners. Copyright © 2017 Elsevier B.V. All rights reserved.

  12. Viewing ageing eyes: diverse sites of amyloid Beta accumulation in the ageing mouse retina and the up-regulation of macrophages.

    Directory of Open Access Journals (Sweden)

    Jaimie Hoh Kam

    Full Text Available BACKGROUND: Amyloid beta (Aβ accumulates in the ageing central nervous system and is associated with a number of age-related diseases, including age-related macular degeneration (AMD in the eye. AMD is characterised by accumulation of extracellular deposits called drusen in which Aβ is a key constituent. Aβ activates the complement cascade and its deposition is associated with activated macrophages. So far, little is known about the quantitative measurements of Aβ accumulation and definitions of its relative sites of ocular deposition in the normal ageing mouse. METHODOLOGY/PRINCIPAL FINDINGS: We have traced Aβ accumulation quantitatively in the ageing mouse retina using immunohistochemistry and Western blot analysis. We reveal that it is not only deposited at Bruch's membrane and along blood vessels, but unexpectedly, it also coats photoreceptor outer segments. While Aβ is present at all sites of deposition from 3 months of age, it increases markedly from 6 months onward. Progressive accumulation of deposits on outer segments was confirmed with scanning electron microscopy, revealing age-related changes in their morphology. Such progress of accumulation of Aβ on photoreceptor outer segments with age was also confirmed in human retinae using immunohistochemistry. We also chart the macrophage response to increases in Aβ showing up-regulation in their numbers using both confocal laser imaging of the eye in vivo followed by in vitro immunostaining. With age macrophages become bloated with cellular debris including Aβ, however, their increasing numbers fail to stop Aβ accumulation. CONCLUSIONS: Increasing Aβ deposition in blood vessels and Bruch's membrane will impact upon retinal perfusion and clearance of cellular waste products from the outer retina, a region of very high metabolic activity. This accumulation of Aβ may contribute to the 30% reduction of photoreceptors found throughout life and the shortening of those that remain. The

  13. HDL functionality in reverse cholesterol transport--Challenges in translating data emerging from mouse models to human disease.

    Science.gov (United States)

    Lee-Rueckert, Miriam; Escola-Gil, Joan Carles; Kovanen, Petri T

    2016-07-01

    Whereas LDL-derived cholesterol accumulates in atherosclerotic lesions, HDL particles are thought to facilitate removal of cholesterol from the lesions back to the liver thereby promoting its fecal excretion from the body. Because generation of cholesterol-loaded macrophages is inherent to atherogenesis, studies on the mechanisms stimulating the release of cholesterol from these cells and its ultimate excretion into feces are crucial to learn how to prevent lesion development or even induce lesion regression. Modulation of this key anti-atherogenic pathway, known as the macrophage-specific reverse cholesterol transport, has been extensively studied in several mouse models with the ultimate aim of applying the emerging knowledge to humans. The present review provides a detailed comparison and critical analysis of the various steps of reverse cholesterol transport in mouse and man. We attempt to translate this in vivo complex scenario into practical concepts, which could serve as valuable tools when developing novel HDL-targeted therapies.

  14. The cholesterol-binding protein NPC2 restrains recruitment of stromal macrophage-lineage cells to early-stage lung tumours.

    Science.gov (United States)

    Kamata, Tamihiro; Jin, Hong; Giblett, Susan; Patel, Bipin; Patel, Falguni; Foster, Charles; Pritchard, Catrin

    2015-07-16

    The tumour microenvironment is known to play an integral role in facilitating cancer progression at advanced stages, but its function in some pre-cancerous lesions remains elusive. We have used the (V600) (E)BRAF-driven mouse lung model that develop premalignant lesions to understand stroma-tumour interactions during pre-cancerous development. In this model, we have found that immature macrophage-lineage cells (IMCs) producing PDGFA, TGFβ and CC chemokines are recruited to the stroma of premalignant lung adenomas through CC chemokine receptor 1 (CCR1)-dependent mechanisms. Stromal IMCs promote proliferation and transcriptional alterations suggestive of epithelial-mesenchymal transition in isolated premalignant lung tumour cells ex vivo, and are required for the maintenance of early-stage lung tumours in vivo. Furthermore, we have found that IMC recruitment to the microenvironment is restrained by the cholesterol-binding protein, Niemann-Pick type C2 (NPC2). Studies on isolated cells ex vivo confirm that NPC2 is secreted from tumour cells and is taken up by IMCs wherein it suppresses secretion of the CCR1 ligand CC chemokine 6 (CCL6), at least in part by facilitating its lysosomal degradation. Together, these findings show that NPC2 secreted by premalignant lung tumours suppresses IMC recruitment to the microenvironment in a paracrine manner, thus identifying a novel target for the development of chemopreventive strategies in lung cancer.

  15. Environmental impact of multi-wall carbon nanotubes in a novel model of exposure: systemic distribution, macrophage accumulation, and amyloid deposition.

    Science.gov (United States)

    Albini, Adriana; Pagani, Arianna; Pulze, Laura; Bruno, Antonino; Principi, Elisa; Congiu, Terenzio; Gini, Elisabetta; Grimaldi, Annalisa; Bassani, Barbara; De Flora, Silvio; de Eguileor, Magda; Noonan, Douglas M

    2015-01-01

    Carbon nanotubes (CNTs) have been extensively investigated and employed for industrial use because of their peculiar physical properties, which make them ideal for many industrial applications. However, rapid growth of CNT employment raises concerns about the potential risks and toxicities for public health, environment, and workers associated with the manufacture and use of these new materials. Here we investigate the main routes of entry following environmental exposure to multi-wall CNTs (MWCNTs; currently the most widely used in industry). We developed a novel murine model that could represent a surrogate of a workplace exposure to MWCNTs. We traced the localization of MWCNTs and their possible role in inducing an innate immune response, inflammation, macrophage recruitment, and inflammatory conditions. Following environmental exposure of CD1 mice, we observed that MWCNTs rapidly enter and disseminate in the organism, initially accumulating in lungs and brain and later reaching the liver and kidney via the bloodstream. Since recent experimental studies show that CNTs are associated with the aggregation process of proteins associated with neurodegenerative diseases, we investigated whether MWCNTs are able to induce amyloid fibril production and accumulation. Amyloid deposits in spatial association with macrophages and MWCNT aggregates were found in the brain, liver, lungs, and kidneys of exposed animals. Our data suggest that accumulation of MWCNTs in different organs is associated with inflammation and amyloid accumulation. In the brain, where we observed rapid accumulation and amyloid fibril deposition, exposure to MWCNTs might enhance progression of neurodegenerative and other amyloid-related diseases. Our data highlight the conclusion that, in a novel rodent model of exposure, MWCNTs may induce macrophage recruitment, activation, and amyloid deposition, causing potential damage to several organs.

  16. {sup 18}F-FDG PET and intravascular ultrasonography (IVUS) images compared with histology of atherosclerotic plaques: {sup 18}F-FDG accumulates in foamy macrophages

    Energy Technology Data Exchange (ETDEWEB)

    Ishino, Seigo [Takeda Pharmaceutical Company Limited, Pharmaceutical Research Division, Fujisawa (Japan); Takeda Pharmaceutical Company Limited, Biomolecular Research Laboratories, Pharmaceutical Research Division, Fujisawa, Kanagawa (Japan); Ogawa, Mikako; Magata, Yasuhiro [Hamamatsu University School of Medicine, Medical Photonics Research Center, Hamamatsu (Japan); Mori, Ikuo; Nishimura, Satoshi; Ikeda, Shota; Sugita, Taku; Oikawa, Tatsuo; Horiguchi, Takashi [Takeda Pharmaceutical Company Limited, Pharmaceutical Research Division, Fujisawa (Japan)

    2014-04-15

    Intravascular ultrasonography (IVUS) and {sup 18}F-FDG PET have been used to evaluate the efficacy of antiatherosclerosis drugs. These two modalities image different characteristics of atherosclerotic plaques, and a comparison of IVUS and PET images with histology has not been performed. The aim of this study was to align IVUS and PET images using anatomic landmarks in Watanabe heritable hyperlipidaemic (WHHL) rabbits, enabling comparison of their depiction of aortic atherosclerosis. Cellular {sup 18}F-FDG localization was evaluated by {sup 3}H-FDG microautoradiography (micro-ARG). A total of 19 WHHL rabbits (7 months of age) were divided into three groups: baseline (n = 6), 3 months (n = 4), and 6 months (n = 9). PET, IVUS and histological images of the same aortic segments were analysed. Infiltration by foamy macrophages was scored from 0 to IV using haematoxylin and eosin (H and E) and antimacrophage immunohistochemical staining, and compared with {sup 3}H-FDG micro-ARG findings in two additional WHHL rabbits. IVUS images did not identify foamy macrophage deposition but revealed the area of intimal lesions (r = 0.87). {sup 18}F-FDG PET revealed foamy macrophage distribution in the plaques. The intensity of {sup 18}F-FDG uptake was correlated positively with the degree of foamy macrophage infiltration. Micro-ARG showed identical {sup 3}H-FDG accumulation in the foamy macrophages surrounding the lipid core of the plaques. F-FDG PET localized and quantified the degree of infiltration of foamy macrophages in atherosclerotic lesions. IVUS defined the size of lesions. {sup 18}F-FDG PET is a promising imaging technique for evaluating atherosclerosis and for monitoring changes in the composition of atherosclerotic plaques affecting their stability. (orig.)

  17. Macrophages expressing arginase 1 and nitric oxide synthase 2 accumulate in the small intestine during Giardia lamblia infection.

    Science.gov (United States)

    Maloney, Jenny; Keselman, Aleksander; Li, Erqiu; Singer, Steven M

    2015-06-01

    Nitric oxide (NO) has been shown to inhibit Giardia lamblia in vitro and in vivo. This study sought to determine if Giardia infection induces arginase 1 (ARG1) expression in host macrophages to reduce NO production. Stimulations of RAW 264.7 macrophage-like cells with Giardia extract induced arginase activity. Real-time PCR and immunohistochemistry showed increased ARG1 and nitric oxide synthase 2 (NOS2) expression in mouse intestine following infection. Flow cytometry demonstrated increased numbers of macrophages positive for both ARG1 and NOS2 in lamina propria following infection, but there was no evidence of increased expression of ARG1 in these cells.

  18. microRNA-150 inhibits the formation of macrophage foam cells through targeting adiponectin receptor 2

    Energy Technology Data Exchange (ETDEWEB)

    Li, Jing [Department of Geratory, Linzi District People’s Hospital of Zibo City, Zibo, Shandong (China); Zhang, Suhua, E-mail: drsuhuangzhang@qq.com [Department of HealthCare, Qilu Hospital of Shandong University (Qingdao), Qingdao City, Qingdao (China)

    2016-08-05

    Transformation of macrophages into foam cells plays a critical role in the pathogenesis of atherosclerosis. The aim of this study was to determine the expression and biological roles of microRNA (miR)-150 in the formation of macrophage foam cells and to identify its functional target(s). Exposure to 50 μg/ml oxidized low-density lipoprotein (oxLDL) led to a significant upregulation of miR-150 in THP-1 macrophages. Overexpression of miR-150 inhibited oxLDL-induced lipid accumulation in THP-1 macrophages, while knockdown of miR-150 enhanced lipid accumulation. apoA-I- and HDL-mediated cholesterol efflux was increased by 66% and 43%, respectively, in miR-150-overexpressing macrophages relative to control cells. In contrast, downregulation of miR-150 significantly reduced cholesterol efflux from oxLDL-laden macrophages. Bioinformatic analysis and luciferase reporter assay revealed adiponectin receptor 2 (AdipoR2) as a direct target of miR-150. Small interfering RNA-mediated downregulation of AdipoR2 phenocopied the effects of miR-150 overexpression, reducing lipid accumulation and facilitating cholesterol efflux in oxLDL-treated THP-1 macrophages. Knockdown of AdipoR2 induced the expression of proliferator-activated receptor gamma (PPARγ), liver X receptor alpha (LXRα), ABCA1, and ABCG1. Moreover, pharmacological inhibition of PPARγ or LXRα impaired AdipoR2 silencing-induced upregulation of ABCA1 and ABCG1. Taken together, our results indicate that miR-150 can attenuate oxLDL-induced lipid accumulation in macrophages via promotion of cholesterol efflux. The suppressive effects of miR-150 on macrophage foam cell formation are mediated through targeting of AdipoR2. Delivery of miR-150 may represent a potential approach to prevent macrophage foam cell formation in atherosclerosis. -- Highlights: •miR-150 inhibits macrophage foam cell formation. •miR-150 accelerates cholesterol efflux from oxLDL-laden macrophages. •miR-150 suppresses macrophage foam cell

  19. Dermatan sulfate reduces monocyte chemoattractant protein 1 and TGF-β production, as well as macrophage recruitment and myofibroblast accumulation in mice with unilateral ureteral obstruction

    Directory of Open Access Journals (Sweden)

    C.L.R. Belmiro

    2011-07-01

    Full Text Available Selectins play an essential role in most inflammatory reactions, mediating the initial leukocyte-rolling event on activated endothelium. Heparin and dermatan sulfate (DS bind and block P- and L-selectin function in vitro. Recently, we reported that subcutaneous administration of DS inhibits colon inflammation in rats by reducing macrophage and T-cell recruitment and macrophage activation. In the present study, we examined the effect of porcine intestinal mucosa DS on renal inflammation and fibrosis in mice after unilateral ureteral obstruction (UUO. Twenty-four adult male Swiss mice weighing 20-25 g were divided into 4 groups: group C (N = 6 was not subjected to any surgical manipulation; group SH (N = 6 was subjected to surgical manipulation but without ureter ligation; group UUO (N = 6 was subjected to unilateral ureteral obstruction and received no treatment; group UUO plus DS (N = 6 was subjected to UUO and received DS (4 mg/kg subcutaneously daily for 14 days. An immunoblot study was also performed for TGF-β. Collagen (stained area ~3700 µm², MCP-1 (stained area ~1700 µm², TGF-β (stained area ~13% of total area, macrophage (number of cells ~40, and myofibroblast (stained area ~1900 µm² levels were significantly (P < 0.05 higher in the UUO group compared to control. DS treatment significantly (P < 0.05 reduced the content of collagen (stained area ~700 µm², MCP-1 (stained area ~160 µm² and TGF-β (stained area ~5% of total area, in addition to myofibroblast (stained area ~190 µm² and macrophage (number of cells ~32 accumulation in the obstructed kidney. Overall, these results indicate that DS attenuates kidney inflammation by reducing macrophage recruitment, myofibroblast population and fibrosis in mice submitted to UUO.

  20. L-FABP T94A decreased fatty acid uptake and altered hepatic triglyceride and cholesterol accumulation in Chang liver cells stably transfected with L-FABP.

    Science.gov (United States)

    Gao, Na; Qu, Xia; Yan, Jin; Huang, Qi; Yuan, Hao-Yong; Ouyang, Dong-Sheng

    2010-12-01

    Liver fatty acid-binding protein (L-FABP, FABP1) is a highly conserved key factor in lipid metabolism. This study was undertaken to verify whether the T94A mutation in the L-FABP gene affects fatty acid uptake and intracellular esterification into specific lipid pools. Candidate SNPs were recreated using site-directed mutagenesis and tested for physical function in stably transfected Chang liver cell lines. We found that the T94A mutant of L-FABP lowered FFA uptake but had no effect on FFA efflux. L-FABP T94A-expressing cells showed decreased triglyceride content and increased cholesterol accumulation compared to the wild-type control for cells incubated with an FFA mixture (oleate: palmitate, 2:1 ratio). In conclusion, our study provided additional indications of the functional relevance of the L-FABP T94A SNP in hepatic fatty acid and lipid metabolism in humans.

  1. Attenuated Pik3r1 Expression Prevents Insulin Resistance and Adipose Tissue Macrophage Accumulation in Diet-Induced Obese Mice

    OpenAIRE

    McCurdy, Carrie E.; Schenk, Simon; Holliday, Michael J.; Philp, Andrew; Houck, Julie A.; Patsouris, David; MacLean, Paul S.; Majka, Susan M.; Klemm, Dwight J.; Friedman, Jacob E. (Jed)

    2012-01-01

    Obese white adipose tissue (AT) is characterized by large-scale infiltration of proinflammatory macrophages, in parallel with systemic insulin resistance; however, the cellular stimulus that initiates this signaling cascade and chemokine release is still unknown. The objective of this study was to determine the role of the phosphoinositide 3-kinase (PI3K) regulatory subunits on AT macrophage (ATM) infiltration in obesity. Here, we find that the Pik3r1 regulatory subunits (i.e., p85α/p55α/p50α...

  2. The Distribution of Macrophages and the Mechanism of Macrophages Accumulation in Atheroscle-rotic Plaques%动脉粥样硬化斑块中巨噬细胞的分布与蓄积机制

    Institute of Scientific and Technical Information of China (English)

    王林青; 李全忠; 钱宗杰

    2016-01-01

    动脉粥样硬化斑块破裂可导致严重的临床事件(如心肌梗死和脑卒中)。巨噬细胞是动脉粥样硬化斑块内最主要的炎性细胞,它可根据不同的微环境分化成不同表型的巨噬细胞。其中, M1型巨噬细胞主要位于斑块不稳定区,M2型巨噬细胞主要位于斑块的稳定区。随着动脉粥样硬化斑块的进展,斑块内积聚的巨噬细胞逐渐增多,而斑块内不断蓄积的巨噬细胞主要依赖于局部巨噬细胞的增殖,而不是血中单核细胞的分化。%The rupture of atherosclerotic plaque can lead to severe consequences, such as myocardial infraction and stroke.Macrophages are the predominant inflammatory cells within the plaques,which are very versatile and can polarize different phenotypes depending on the local microenvironment .M1 macrophages are exclusively found in unstable plaques and M2 macrophages being higher in stable plaques.The incremental accumulation of macrophages corresponded with plaque progression,are mainly derived from local prolifera-tion rather than from the influx of blood-borne monocytes.

  3. Arteriogenesis depends on circulating monocytes and macrophage accumulation and is severely depressed in op/op mice

    NARCIS (Netherlands)

    C.E. Bergmann; I.E. Hoefer; B. Meder; H. Roth; N. van Royen; S.M. Breit; M.M. Jost; S. Aharinejad; S. Hartmann; I.R. Buschmann

    2006-01-01

    It has been suggested that monocytes/macrophages represent the pivotal cell type during early adaptive growth of pre-existent arterial anastomoses toward functional collateral arteries (arteriogenesis) upon arterial occlusion. This hypothesis was supported by previous studies providing evidence that

  4. Tracking Monocyte Recruitment and Macrophage Accumulation in Atherosclerotic Plaque Progression Using a Novel hCD68GFP/ApoE−/− Reporter Mouse—Brief Report

    Science.gov (United States)

    Iqbal, Asif J.; Jones, Daniel; Patel, Jyoti; Coutinho, Patricia; Taylor, Lewis; Greaves, David R.; Channon, Keith M.

    2017-01-01

    Objective— To create a model of atherosclerosis using green fluorescent protein (GFP)–targeted monocytes/macrophages, allowing analysis of both endogenous GFP+ and adoptively transferred GFP+ myeloid cells in arterial inflammation. Approach and Results— hCD68GFP reporter mice were crossed with ApoE−/− mice. Expression of GFP was localized to macrophages in atherosclerotic plaques and in angiotensin II–induced aortic aneurysms and correlated with galectin 3 and mCD68 expression. Flow cytometry confirmed GFP+ expression in CD11b+/CD64+, CD11c+/MHC-IIHI, and CD11b+/F4/80+ myeloid cells. Adoptive transfer of GFP+ monocytes demonstrated monocyte recruitment to both adventitia and atherosclerotic plaque, throughout the aortic root, within 72 hours. We demonstrated the biological utility of hCD68GFP monocytes by comparing the recruitment of wild-type and CCR2−/− monocytes to sites of inflammation. Conclusions— hCD68GFP/ApoE−/− mice provide a new approach to study macrophage accumulation in atherosclerotic plaque progression and to identify cells recruited from adoptively transferred monocytes. PMID:27908893

  5. Cholesterol Test

    Science.gov (United States)

    ... AACC products and services. Advertising & Sponsorship: Policy | Opportunities Cholesterol Share this page: Was this page helpful? Also known as: Blood Cholesterol Formal name: Total Cholesterol Related tests: HDL Cholesterol , ...

  6. What's Cholesterol?

    Science.gov (United States)

    ... los dientes Video: Getting an X-ray What's Cholesterol? KidsHealth > For Kids > What's Cholesterol? Print A A ... thing for food to be low in it? Cholesterol and Your Body Cholesterol (say: kuh-LES-tuh- ...

  7. What's Cholesterol?

    Science.gov (United States)

    ... Room? What Happens in the Operating Room? What's Cholesterol? KidsHealth > For Kids > What's Cholesterol? A A A ... thing for food to be low in it? Cholesterol and Your Body Cholesterol (say: kuh-LES-tuh- ...

  8. The role of high cholesterol-high fructose diet on coronary arteriosclerosis.

    Science.gov (United States)

    Swier, Vicki J; Tang, Lin; Radwan, Mohamed M; Hunter, William J; Agrawal, Devendra K

    2016-02-01

    The effect of fructose in conjunction with high cholesterol diet in the development of atherosclerotic lesions in coronary arteries is not well established. Microswine were fed high cholesterol (HC) or a high cholesterol-high fructose (HCHF) diet containing 18-20% calories from fructose. All swine had high levels of serum cholesterol and non-HDL, thickened intima and accumulation of collagen in the coronaries. Swine fed with HC diet had less stenosis in coronary arteries, lower serum levels of non-HDL, triglycerides, cholesterol, and blood glucose than HCHF group. Coronary lesions in the HC swine were not as progressed as in HCHF and showed low LDL-expressed lipid-laden foam cells. The M1/M2 macrophage phenotype in the HCHF swine differed with the progression of atherosclerosis, with higher density of M1-phenotype in HCHF swine. There was high expression of CCR7 (M1-phenotype) in more advanced lesions in the fibrous cap-like areas, whereas M2-macrophages were abundant in the foam-cell cores. These findings suggest that the addition of a fructose to high cholesterol diet accelerates atherosclerotic lesions in coronary arteries with an increase in M1-macrophages and the propensity to develop features of metabolic syndrome.

  9. 三磷酸腺苷结合盒转运体A1在巨噬细胞胆固醇流出中的作用%Effects of ATP binding cassette transporter A1 on cholesterol efflux in macrophages

    Institute of Scientific and Technical Information of China (English)

    唐朝克; 严鹏科; 杨永宗

    2003-01-01

    Tangier disease is caused by mutations in ATP binding cassette transporter AI( ABCA1).ABCA1 interacts with lipid-free apolipoproteins, promoting phospholipid and cholesterol ettlux fzom cells and giving rise to HDL particles. ABCA1 may act as a phospholipid translocase facilitating phospholipid binding to apoA-Ⅰ. ABCA1 gene expression is upregulated in cholesterol-loaded cells as a result of activation of IXR/RXR- mediated gene transcription. LXR and RXR coordinately induce a battery of genes mediating cellular cholesterol efllux, centripetal cholesterol tramport, and cholesterol excretion in bile. Small- molecule activators of LXR/RXR or other stimulators of macrophage or intestinal cholesterol efl]ux hold great promise as future treat-ments for atherosclerosis.

  10. Biliary cholesterol secretion: More than a simple ABC

    Institute of Scientific and Technical Information of China (English)

    Arne; Dikkers; Uwe; JF; Tietge

    2010-01-01

    Biliary cholesterol secretion is a process important for 2 major disease complexes, atherosclerotic cardiovascular disease and cholesterol gallstone disease. With respect to cardiovascular disease, biliary cholesterol secretion is regarded as the f inal step for the elimination of cholesterol originating from cholesterol-laden macrophage foam cells in the vessel wall in a pathway named reverse cholesterol transport. On the other hand, cholesterol hypersecretion into the bile is considered the main pathophys...

  11. Biliary cholesterol secretion: More than a simple ABC

    OpenAIRE

    Dikkers, Arne; Tietge, Uwe JF

    2010-01-01

    Biliary cholesterol secretion is a process important for 2 major disease complexes, atherosclerotic cardiovascular disease and cholesterol gallstone disease. With respect to cardiovascular disease, biliary cholesterol secretion is regarded as the final step for the elimination of cholesterol originating from cholesterol-laden macrophage foam cells in the vessel wall in a pathway named reverse cholesterol transport. On the other hand, cholesterol hypersecretion into the bile is considered the ...

  12. Insulin resistance is associated with MCP1-mediated macrophage accumulation in skeletal muscle in mice and humans.

    Directory of Open Access Journals (Sweden)

    David Patsouris

    Full Text Available Inflammation is now recognized as a major factor contributing to type 2 diabetes (T2D. However, while the mechanisms and consequences associated with white adipose tissue inflammation are well described, very little is known concerning the situation in skeletal muscle. The aim of this study was to investigate, in vitro and in vivo, how skeletal muscle inflammation develops and how in turn it modulates local and systemic insulin sensitivity in different mice models of T2D and in humans, focusing on the role of the chemokine MCP1. Here, we found that skeletal muscle inflammation and macrophage markers are increased and associated with insulin resistance in mice models and humans. In addition, we demonstrated that intra-muscular TNFα expression is exclusively restricted to the population of intramuscular leukocytes and that the chemokine MCP1 was associated with skeletal muscle inflammatory markers in these models. Furthermore, we demonstrated that exposure of C2C12 myotubes to palmitate elevated the production of the chemokine MCP1 and that the muscle-specific overexpression of MCP1 in transgenic mice induced the local recruitment of macrophages and altered local insulin sensitivity. Overall our study demonstrates that skeletal muscle inflammation is clearly increased in the context of T2D in each one of the models we investigated, which is likely consecutive to the lipotoxic environment generated by peripheral insulin resistance, further increasing MCP1 expression in muscle. Consequently, our results suggest that MCP1-mediated skeletal muscle macrophages recruitment plays a role in the etiology of T2D.

  13. Downregulation of miR-150 Expression by DNA Hypermethylation Is Associated with High 2-Hydroxy-(4-methylthio)butanoic Acid-Induced Hepatic Cholesterol Accumulation in Nursery Piglets.

    Science.gov (United States)

    Jia, Yimin; Ling, Mingfa; Zhang, Luchu; Jiang, Shuxia; Sha, Yusheng; Zhao, Ruqian

    2016-10-12

    Excess 2-hydroxy-(4-methylthio)butanoic acid (HMB) supplementation induces hyperhomocysteinemia, which contributes to hepatic cholesterol accumulation. However, it is unclear whether and how high levels of HMB break hepatic cholesterol homeostasis in nursery piglets. In this study, HMB oversupplementation suppressed food intake and decreased body weight in nursery piglets. Hyperhomocysteinemia and higher hepatic cholesterol accumulation were observed in HMB groups. Accordingly, HMB significantly increased the protein content of 3-hydroxy-3-methylglutaryl coenzyme A reductase (HMGCR) and glycine N-methyltransferase (GNMT) but decreased that of acyl-coenzyme A:cholesterol acyltransferase-1 (ACAT1). Significant downregulation of miR-150, miR-181d-5p, and miR-296-3p targeting the 3'-untranslated regions (UTRs) of GNMT and HMGCR was detected in the liver of HMB-treated piglets, and their functional validation was confirmed by dual-luciferase reporter assay. Furthermore, hypermethylation of miR-150 promoter was detected in association with suppressed miR-150 expression in the livers of HMB-treated piglets. This study indicated a new mechanism of hepatic cholesterol unhomeostasis by dietary methyl donor supplementation.

  14. Effects of dietary palmitoleic acid on plasma lipoprotein profile and aortic cholesterol accumulation are similar to those of other unsaturated fatty acids in the F1B golden Syrian hamster.

    Science.gov (United States)

    Matthan, Nirupa R; Dillard, Alice; Lecker, Jaime L; Ip, Blanche; Lichtenstein, Alice H

    2009-02-01

    The lower susceptibility of palmitoleic acid (16:1) to oxidation compared to PUFA may confer functional advantages with respect to finding acceptable alternatives to partially hydrogenated fats, but limited data are available on its effect on cardiovascular risk factors. This study investigated the effect of diets (10% fat, 0.1% cholesterol, wt:wt) enriched with macadamia [monounsaturated fatty acid (MUFA)16:1], palm (SFA,16:0), canola (MUFA,18:1), or safflower (PUFA,18:2) oils on lipoprotein profiles and aortic cholesterol accumulation in F1B Golden Syrian hamsters (n = 16/group). After 12 wk, 8 hamsters in each group were killed (phase 1). The remaining hamsters fed palm oil were changed to a diet containing coconut oil, while hamsters in the other diet groups continued on their original diets for an additional 6 wk (phase 2). With minor exceptions, the time course and dietary SFA source did not alter the study outcomes. Macadamia oil-fed hamsters had lower non-HDL cholesterol and triglyceride concentrations compared with the palm and coconut oil-fed hamsters and higher HDL-cholesterol compared with the coconut, canola, and safflower oil-fed hamsters. The aortic cholesterol concentration was not affected by dietary fat type. The hepatic cholesterol concentration was higher in the unsaturated compared with the saturated oil-fed hamsters. RBC membrane and aortic cholesteryl ester, triglyceride, and phospholipid fatty acid profiles reflected that of the dietary oil. These data suggest that an oil relatively high in palmitoleic acid does not adversely affect plasma lipoprotein profiles or aortic cholesterol accumulation and was similar to other unsaturated fatty acid-rich oils.

  15. Chronic endocannabinoid system stimulation induces muscle macrophage and lipid accumulation in type 2 diabetic mice independently of metabolic endotoxaemia.

    Directory of Open Access Journals (Sweden)

    Lucie Geurts

    Full Text Available AIMS: Obesity and type 2 diabetes are characterised by low-grade inflammation, metabolic endotoxaemia (i.e., increased plasma lipopolysaccharides [LPS] levels and altered endocannabinoid (eCB-system tone. The aim of this study was to decipher the specific role of eCB-system stimulation or metabolic endotoxaemia in the onset of glucose intolerance, metabolic inflammation and altered lipid metabolism. METHODS: Mice were treated with either a cannabinoid (CB receptor agonist (HU210 or low-dose LPS using subcutaneous mini-pumps for 6 weeks. After 3 weeks of the treatment under control (CT diet, one-half of each group of mice were challenged with a high fat (HF diet for the following 3-week period. RESULTS: Under basal conditions (control diet, chronic CB receptor agonist treatment (i.e., 6 weeks induced glucose intolerance, stimulated metabolic endotoxaemia, and increased macrophage infiltration (CD11c and F4/80 expression in the muscles; this phenomenon was associated with an altered lipid metabolism (increased PGC-1α expression and decreased CPT-1b expression in this tissue. Chronic LPS treatment tended to increase the body weight and fat mass, with minor effects on the other metabolic parameters. Challenging mice with an HF diet following pre-treatment with the CB agonist exacerbated the HF diet-induced glucose intolerance, the muscle macrophage infiltration and the muscle's lipid content without affecting the body weight or the fat mass. CONCLUSION: Chronic CB receptor stimulation under basal conditions induces glucose intolerance, stimulates metabolic inflammation and alters lipid metabolism in the muscles. These effects worsen following the concomitant ingestion of an HF diet. Here, we highlight the central roles played by the eCB system and LPS in the pathophysiology of several hallmarks of obesity and type 2 diabetes.

  16. About Cholesterol

    Science.gov (United States)

    ... Artery Disease Venous Thromboembolism Aortic Aneurysm More About Cholesterol Updated:Apr 3,2017 It may surprise you ... our bodies to keep us healthy. What is cholesterol and where does it come from? Cholesterol is ...

  17. Cholesterol Levels

    Science.gov (United States)

    ... this page: https://medlineplus.gov/labtests/cholesterollevels.html Cholesterol Levels To use the sharing features on this page, please enable JavaScript. What is a Cholesterol Test? Cholesterol is a waxy, fat-like substance ...

  18. Cytokines, macrophage lipid metabolism and foam cells: implications for cardiovascular disease therapy.

    Science.gov (United States)

    McLaren, James E; Michael, Daryn R; Ashlin, Tim G; Ramji, Dipak P

    2011-10-01

    Cardiovascular disease is the biggest killer globally and the principal contributing factor to the pathology is atherosclerosis; a chronic, inflammatory disorder characterized by lipid and cholesterol accumulation and the development of fibrotic plaques within the walls of large and medium arteries. Macrophages are fundamental to the immune response directed to the site of inflammation and their normal, protective function is harnessed, detrimentally, in atherosclerosis. Macrophages contribute to plaque development by internalizing native and modified lipoproteins to convert them into cholesterol-rich foam cells. Foam cells not only help to bridge the innate and adaptive immune response to atherosclerosis but also accumulate to create fatty streaks, which help shape the architecture of advanced plaques. Foam cell formation involves the disruption of normal macrophage cholesterol metabolism, which is governed by a homeostatic mechanism that controls the uptake, intracellular metabolism, and efflux of cholesterol. It has emerged over the last 20 years that an array of cytokines, including interferon-γ, transforming growth factor-β1, interleukin-1β, and interleukin-10, are able to manipulate these processes. Foam cell targeting, anti-inflammatory therapies, such as agonists of nuclear receptors and statins, are known to regulate the actions of pro- and anti-atherogenic cytokines indirectly of their primary pharmacological function. A clear understanding of macrophage foam cell biology will hopefully enable novel foam cell targeting therapies to be developed for use in the clinical intervention of atherosclerosis.

  19. Multiple mechanisms limit the accumulation of unesterified cholesterol in the small intestine of mice deficient in both ACAT2 and ABCA1.

    Science.gov (United States)

    Turley, Stephen D; Valasek, Mark A; Repa, Joyce J; Dietschy, John M

    2010-11-01

    Cholesterol homeostasis in the enterocyte is regulated by the interplay of multiple genes that ultimately determines the net amount of cholesterol reaching the circulation from the small intestine. The effect of deleting these genes, particularly acyl CoA:cholesterol acyl transferase 2 (ACAT2), on cholesterol absorption and fecal sterol excretion is well documented. We also know that the intestinal mRNA level for adenosine triphosphate-binding cassette transporter A1 (ABCA1) increases in Acat2(-/-) mice. However, none of these studies has specifically addressed how ACAT2 deficiency impacts the relative proportions of esterified and unesterified cholesterol (UC) in the enterocyte and whether the concurrent loss of ABCA1 might result in a marked buildup of UC. Therefore, the present studies measured the expression of numerous genes and related metabolic parameters in the intestine and liver of ACAT2-deficient mice fed diets containing either added cholesterol or ezetimibe, a selective sterol absorption inhibitor. Cholesterol feeding raised the concentration of UC in the small intestine, and this was accompanied by a significant reduction in the relative mRNA level for Niemann-Pick C1-like 1 (NPC1L1) and an increase in the mRNA level for both ABCA1 and ABCG5/8. All these changes were reversed by ezetimibe. When mice deficient in both ACAT2 and ABCA1 were fed a high-cholesterol diet, the increase in intestinal UC levels was no greater than it was in mice lacking only ACAT2. This resulted from a combination of compensatory mechanisms including diminished NPC1L1-mediated cholesterol uptake, increased cholesterol efflux via ABCG5/8, and possibly rapid cell turnover.

  20. Effect of Niacin on Cholesterol Efflux in Macrophage Raw264.7 Cells%烟酸对巨噬细胞 raw264.7胆固醇流出的影响

    Institute of Scientific and Technical Information of China (English)

    董静; 施文剑; 赵水平

    2013-01-01

    [Objective]To observe the effect of niacin on cholesterol efflux in macrophages,and to explore the possible mechanism.[Methods]Macrophage 264.7 cells were incubated in the medium containing various concentration of niacin (0~5.0mM)for 24h.Reverse transcription polymerase chain reaction(RT-PCR)was used to determine the expression of adenosine triphosphate-binding cassette transporter G1(ABCG1),liver X-receptor a(LXRa)and peroxisome proliferator-activated receptor-γ(PPARγ),and Western blot was used to detect the protein expression of ABCG1 and LXRa in macrophages.Liquid scintillation counter was used to de-tect cholesterol efflux.[Results]Niacin dose-dependently increased the mRNA and protein expression of AB-CG1 and promoted ABCG1-mediated cholesterol efflux in Raw264.7 cells.The expression of LXRa and PPARγin Raw264.7 cells was high.Compared with control group,the expression of LXRa and PPARγinter-vened by niacin 5.0mM increased obviously.[Conclusion]Niacin can promote cholesterol efflux pathway me-diated by ABCG1,which may be associated with the up-regulation of LXRa and PPARγ expression.It can provide the clue to explain the mechanisms of high density lipoprotein cholesterol raised by niacin.%[目的]观察烟酸对巨噬细胞胆固醇流出的影响并探讨其机制。[方法]对巨噬细胞(raw 264.7细胞株)给予不同浓度的烟酸(0~5.0 mM)干预24 h 后,收集细胞,反转录聚合酶链反应测定巨噬细胞三磷酸腺苷结合盒转运体 G1(ABCG1),肝 X 受体 a(LXRa)和过氧化物酶增殖物激活受体γ(PPARγ)mRNA 表达及 Western blot 印迹检测 ABCG1和 LXRa 蛋白表达,采用液体闪烁计数器检测细胞内胆固醇流出。[结果]烟酸呈剂量依赖性增加巨噬细胞 ABCG1 mRNA 及蛋白的表达,并促进其介导的胆固醇流出。LXRa 和PPARγ在巨噬细胞有较高水平的表达,与空白组比较,LXRa,PPARγ表达在5.0 mM 浓度的烟酸干预时明显升高。[

  1. Incremental replacement of saturated fats by n-3 fatty acids in high-fat, high-cholesterol diets reduces elevated plasma lipid levels and arterial lipoprotein lipase, macrophages and atherosclerosis in LDLR-/- mice.

    Science.gov (United States)

    Chang, Chuchun L; Torrejon, Claudia; Jung, Un Ju; Graf, Kristin; Deckelbaum, Richard J

    2014-06-01

    Effects of progressive substitution of dietary n-3 fatty acids (FA) for saturated FA (SAT) on modulating risk factors for atherosclerosis have not been fully defined. Our previous reports demonstrate that SAT increased, but n-3 FA decreased, arterial lipoprotein lipase (LpL) levels and arterial LDL-cholesterol deposition early in atherogenesis. We now questioned whether incremental increases in dietary n-3 FA can counteract SAT-induced pro-atherogenic effects in atherosclerosis-prone LDL-receptor knockout (LDLR-/-) mice and have identified contributing mechanisms. Mice were fed chow or high-fat diets enriched in SAT, n-3, or a combination of both SAT and n-3 in ratios of 3:1 (S:n-3 3:1) or 1:1 (S:n-3 1:1). Each diet resulted in the expected changes in fatty acid composition in blood and aorta for each feeding group. SAT-fed mice became hyperlipidemic. By contrast, n-3 inclusion decreased plasma lipid levels, especially cholesterol. Arterial LpL and macrophage levels were increased over 2-fold in SAT-fed mice but these were decreased with incremental replacement with n-3 FA. n-3 FA partial inclusion markedly decreased expression of pro-inflammatory markers (CD68, IL-6, and VCAM-1) in aorta. SAT diets accelerated advanced atherosclerotic lesion development, whereas all n-3 FA-containing diets markedly slowed atherosclerotic progression. Mechanisms whereby dietary n-3 FA may improve adverse cardiovascular effects of high-SAT, high-fat diets include improving plasma lipid profiles, increasing amounts of n-3 FA in plasma and the arterial wall. Even low levels of replacement of SAT by n-3 FA effectively reduce arterial lipid deposition by decreasing aortic LpL, macrophages and pro-inflammatory markers. Copyright © 2014 Elsevier Ireland Ltd. All rights reserved.

  2. Transcriptional profiling uncovers a network of cholesterol-responsive atherosclerosis target genes.

    Directory of Open Access Journals (Sweden)

    Josefin Skogsberg

    2008-03-01

    Full Text Available Despite the well-documented effects of plasma lipid lowering regimes halting atherosclerosis lesion development and reducing morbidity and mortality of coronary artery disease and stroke, the transcriptional response in the atherosclerotic lesion mediating these beneficial effects has not yet been carefully investigated. We performed transcriptional profiling at 10-week intervals in atherosclerosis-prone mice with human-like hypercholesterolemia and a genetic switch to lower plasma lipoproteins (Ldlr(-/-Apo(100/100Mttp(flox/flox Mx1-Cre. Atherosclerotic lesions progressed slowly at first, then expanded rapidly, and plateaued after advanced lesions formed. Analysis of lesion expression profiles indicated that accumulation of lipid-poor macrophages reached a point that led to the rapid expansion phase with accelerated foam-cell formation and inflammation, an interpretation supported by lesion histology. Genetic lowering of plasma cholesterol (e.g., lipoproteins at this point all together prevented the formation of advanced plaques and parallel transcriptional profiling of the atherosclerotic arterial wall identified 37 cholesterol-responsive genes mediating this effect. Validation by siRNA-inhibition in macrophages incubated with acetylated-LDL revealed a network of eight cholesterol-responsive atherosclerosis genes regulating cholesterol-ester accumulation. Taken together, we have identified a network of atherosclerosis genes that in response to plasma cholesterol-lowering prevents the formation of advanced plaques. This network should be of interest for the development of novel atherosclerosis therapies.

  3. Transcriptional profiling uncovers a network of cholesterol-responsive atherosclerosis target genes.

    Directory of Open Access Journals (Sweden)

    Josefin Skogsberg

    2008-03-01

    Full Text Available Despite the well-documented effects of plasma lipid lowering regimes halting atherosclerosis lesion development and reducing morbidity and mortality of coronary artery disease and stroke, the transcriptional response in the atherosclerotic lesion mediating these beneficial effects has not yet been carefully investigated. We performed transcriptional profiling at 10-week intervals in atherosclerosis-prone mice with human-like hypercholesterolemia and a genetic switch to lower plasma lipoproteins (Ldlr(-/-Apo(100/100Mttp(flox/flox Mx1-Cre. Atherosclerotic lesions progressed slowly at first, then expanded rapidly, and plateaued after advanced lesions formed. Analysis of lesion expression profiles indicated that accumulation of lipid-poor macrophages reached a point that led to the rapid expansion phase with accelerated foam-cell formation and inflammation, an interpretation supported by lesion histology. Genetic lowering of plasma cholesterol (e.g., lipoproteins at this point all together prevented the formation of advanced plaques and parallel transcriptional profiling of the atherosclerotic arterial wall identified 37 cholesterol-responsive genes mediating this effect. Validation by siRNA-inhibition in macrophages incubated with acetylated-LDL revealed a network of eight cholesterol-responsive atherosclerosis genes regulating cholesterol-ester accumulation. Taken together, we have identified a network of atherosclerosis genes that in response to plasma cholesterol-lowering prevents the formation of advanced plaques. This network should be of interest for the development of novel atherosclerosis therapies.

  4. Effects of pomegranate peel polyphenols on lipid accumulation and cholesterol metabolic transformation in L-02 human hepatic cells via the PPARγ-ABCA1/CYP7A1 pathway.

    Science.gov (United States)

    Lv, Ou; Wang, Lifang; Li, Jianke; Ma, Qianqian; Zhao, Wei

    2016-12-07

    To study the effect of pomegranate peel polyphenols on lipid accumulation and cholesterol metabolic transformation in human hepatic cells, purified pomegranate peel polyphenols (PPPs), their main component, punicalagin (PC), and the metabolite of PC, pomegranate ellagic acid (PEA), were chosen as the polyphenols to be tested. At the same time the human hepatocyte cell line L-02 was selected as the experimental cell and a model of steatotic L-02 hepatocytes in vitro was constructed in this paper. The results showed that PPPs, PC and PEA in different concentrations could decrease the total cholesterol (TC) content and increase the total bile acid (TBA) content, and so possess a lipid-lowering effect. The order of the lipid-lowering effect from strong to weak is PEA > PPPs > PC. The relative mRNA expression of peroxisome proliferator-activated receptor γ (PPARγ), ATP-binding cassette transporter A1 (ABCA1) and cholesterol 7α hydroxylase (CYP7A1) was up-regulated by PPPs, PC and PEA in a dose-dependent manner. The effect on the relative mRNA expression can be listed in descending order as: PEA > PPPs > PC. Similar results were found in a western blot analysis. The PPARγ protein, ABCA1 protein and CYP7A1 protein were up-regulated in L-02 cells treated with the three tested polyphenols. All the results indicated that PPPs, PC and PEA could regulate upstream the expression of PPARγ, ABCA1 and CYP7A1, both at transcript and protein levels, to activate the PPARγ-ABCA1/CYP7A1 cell signaling pathway and enhance cholesterol metabolism in L-02 cells. Therefore, PPPs, as a kind of natural material, may be paid more attention in the prevention and treatment of diseases related to excessive cholesterol accumulation.

  5. Oxysterol mixture and, in particular, 27-hydroxycholesterol drive M2 polarization of human macrophages.

    Science.gov (United States)

    Marengo, Barbara; Bellora, Francesca; Ricciarelli, Roberta; De Ciucis, Chiara; Furfaro, AnnaLisa; Leardi, Riccardo; Colla, Renata; Pacini, Davide; Traverso, Nicola; Moretta, Alessandro; Pronzato, Maria Adelaide; Bottino, Cristina; Domenicotti, Cinzia

    2016-01-01

    Macrophages play a crucial role in atherosclerosis progression. Classically activated M1 macrophages have been found in rupture-prone atherosclerotic plaques whereas alternatively activated macrophages, M2, localize in stable plaque. Macrophage accumulation of cholesterol and of its oxidized derivatives (oxysterols) leads to the formation of foam cells, a hallmark of atherosclerotic lesions. In this study, the effects of oxysterols in determining the functional polarization of human macrophages were investigated. Monocytes, purified from peripheral blood mononuclear cells of healthy donors, were differentiated into macrophages (M0) and treated with an oxysterol mixture, cholesterol, or ethanol, every 4 H for a total of 4, 8, and 12 H. The administration of the compounds was repeated in order to maintain the levels of oxysterols constant throughout the treatment. Compared with ethanol treatment, the oxysterol mixture decreased the surface expression of CD36 and CD204 scavenger receptors and reduced the amount of reactive oxygen species whereas it did not affect either cell viability or matrix metalloprotease-9 activity. Moreover, the oxysterol mixture increased the expression of both liver X receptor α and ATP-binding cassette transporter 1. An enhanced secretion of the immunoregulatory cytokine IL-10 accompanied these events. The results supported the hypothesis that the constant levels of oxysterols and, in particular, of 27-hydroxycholesterol stimulate macrophage polarization toward the M2 immunomodulatory functional phenotype, contributing to the stabilization of atherosclerotic plaques.

  6. MD-2 binds cholesterol.

    Science.gov (United States)

    Choi, Soo-Ho; Kim, Jungsu; Gonen, Ayelet; Viriyakosol, Suganya; Miller, Yury I

    2016-02-19

    Cholesterol is a structural component of cellular membranes, which is transported from liver to peripheral cells in the form of cholesterol esters (CE), residing in the hydrophobic core of low-density lipoprotein. Oxidized CE (OxCE) is often found in plasma and in atherosclerotic lesions of subjects with cardiovascular disease. Our earlier studies have demonstrated that OxCE activates inflammatory responses in macrophages via toll-like receptor-4 (TLR4). Here we demonstrate that cholesterol binds to myeloid differentiation-2 (MD-2), a TLR4 ancillary molecule, which is a binding receptor for bacterial lipopolysaccharide (LPS) and is indispensable for LPS-induced TLR4 dimerization and signaling. Cholesterol binding to MD-2 was competed by LPS and by OxCE-modified BSA. Furthermore, soluble MD-2 in human plasma and MD-2 in mouse atherosclerotic lesions carried cholesterol, the finding supporting the biological significance of MD-2 cholesterol binding. These results help understand the molecular basis of TLR4 activation by OxCE and mechanisms of chronic inflammation in atherosclerosis.

  7. Phenolic-extract from argan oil (Argania spinosa L.) inhibits human low-density lipoprotein (LDL) oxidation and enhances cholesterol efflux from human THP-1 macrophages.

    Science.gov (United States)

    Berrougui, Hicham; Cloutier, Martin; Isabelle, Maxim; Khalil, Abdelouahed

    2006-02-01

    Argan oil is rich in unsaturated fatty acids, tocopherol and phenolic compounds. These protective molecules make further study of its cardiovascular diseases (CVDs) action interesting. Furthermore, no previous study has explored the antioxidant activity of argan oil in comparison with olive oil. The present study was conducted to evaluate the beneficial properties of Virgin argan oil phenolic extracts (VAO-PE) towards CVD by: (A) protecting human (low-density lipoprotein, LDL) against lipid peroxidation and (B) promoting high-density lipoprotein (HDL)-mediated cholesterol efflux. Human LDLs were oxidized by incubation with CuSO(4) in the presence of different concentrations of VAO-PE (0-320mug/ml). LDL lipid peroxidation was evaluated by conjugated diene and MDA formation as well as Vitamin E disappearance. Incubation of LDL with VAO-PE significantly prolonged the lag-phase and lowered the progression rate of lipid peroxidation (Pargan oil provides a source of dietary phenolic antioxidants, which prevent cardiovascular diseases by inhibiting LDL-oxidation and enhancing reverse cholesterol transport. These properties increase the anti-atherogenic potential of HDL.

  8. Decreased inducibility of TNF expression in lipid-loaded macrophages

    Directory of Open Access Journals (Sweden)

    Kallin Bengt

    2002-10-01

    Full Text Available Abstract Background Inflammation and immune responses are considered to be very important in the pathogenesis of atherosclerosis. Lipid accumulation in macrophages of the arterial intima is a characteristic feature of atherosclerosis which can influence the inflammatory potential of macrophages. We studied the effects of lipid loading on the regulation of TNF expression in human monocyte-derived macrophages. Results In macrophages incubated with acetylated low density lipoprotein (ac-LDL for 2 days, mRNA expression of TNF in cells stimulated with TNF decreased by 75%. In cell cultures stimulated over night with IL-1β, lipid loading decreased secretion of TNF into culture medium by 48%. These results suggest that lipid accumulation in macrophages makes them less responsive to inflammatory stimuli. Decreased basal activity and inducibility of transcription factor AP-1 was observed in lipid-loaded cells, suggesting a mechanism for the suppression of cytokine expression. NF-κB binding activity and inducibility were only marginally affected by ac-LDL. LDL and ac-LDL did not activate PPARγ. In contrast, oxidized LDL stimulated AP-1 and PPARγ but inhibited NF-κB, indicating that the effects of lipid loading with ac-LDL were not due to oxidation of lipids. Conclusions Accumulation of lipid, mainly cholesterol, results in down-regulation of TNF expression in macrophages. Since monocytes are known to be activated by cell adhesion, these results suggest that foam cells in atherosclerotic plaques may contribute less potently to an inflammatory reaction than newly arrived monocytes/macrophages.

  9. Cholesterol (image)

    Science.gov (United States)

    Cholesterol is a soft, waxy substance that is present in all parts of the body including the ... and obtained from animal products in the diet. Cholesterol is manufactured in the liver and is needed ...

  10. Acrolein impairs the cholesterol transport functions of high density lipoproteins.

    Science.gov (United States)

    Chadwick, Alexandra C; Holme, Rebecca L; Chen, Yiliang; Thomas, Michael J; Sorci-Thomas, Mary G; Silverstein, Roy L; Pritchard, Kirkwood A; Sahoo, Daisy

    2015-01-01

    High density lipoproteins (HDL) are considered athero-protective, primarily due to their role in reverse cholesterol transport, where they transport cholesterol from peripheral tissues to the liver for excretion. The current study was designed to determine the impact of HDL modification by acrolein, a highly reactive aldehyde found in high abundance in cigarette smoke, on the cholesterol transport functions of HDL. HDL was chemically-modified with acrolein and immunoblot and mass spectrometry analyses confirmed apolipoprotein crosslinking, as well as acrolein adducts on apolipoproteins A-I and A-II. The ability of acrolein-modified HDL (acro-HDL) to serve as an acceptor of free cholesterol (FC) from COS-7 cells transiently expressing SR-BI was significantly decreased. Further, in contrast to native HDL, acro-HDL promotes higher neutral lipid accumulation in murine macrophages as judged by Oil Red O staining. The ability of acro-HDL to mediate efficient selective uptake of HDL-cholesteryl esters (CE) into SR-BI-expressing cells was reduced compared to native HDL. Together, the findings from our studies suggest that acrolein modification of HDL produces a dysfunctional particle that may ultimately promote atherogenesis by impairing functions that are critical in the reverse cholesterol transport pathway.

  11. Phospholipase A2-modified low-density lipoprotein activates macrophage peroxisome proliferator-activated receptors.

    Science.gov (United States)

    Namgaladze, Dmitry; Morbitzer, Daniel; von Knethen, Andreas; Brüne, Bernhard

    2010-02-01

    Peroxisome proliferator-activated receptors (PPARs) are ligand-activated transcription factors modulating metabolic and inflammatory responses of phagocytes to stimuli such as fatty acids and their metabolites. We studied the role of PPARs in macrophages exposed to low-density lipoprotein (LDL) modified by secretory phospholipase A(2) (PLA). By analyzing PPAR ligand-binding domain luciferase reporter activation, we observed that PLA-LDL transactivates PPARalpha and PPARdelta, but not PPARgamma. We confirmed that PLA-LDL induced PPAR response element reporter activation by endogenous PPARalpha and PPARdelta in human THP-1 macrophages. By using THP-1 cells with a stable knockdown of PPARalpha and PPARdelta, we showed that PLA-LDL-activated PPARdelta altered macrophage gene expression related to lipid metabolism and lipid droplet formation. Although PPARalpha/delta silencing did not affect cholesterol and triglyceride accumulation in PLA-LDL-treated macrophages, PPARdelta activation by PLA-LDL attenuated macrophage inflammatory gene expression induced by interferon gamma and lipopolysaccharide. PPARdelta activation by PLA-LDL does not influence lipid accumulation in PLA-LDL-treated macrophages. However, it attenuates macrophage inflammatory responses, thus contributing to an anti-inflammatory cell phenotype.

  12. Early extracellular and cellular lipid deposits in aorta of cholesterol-fed rabbits.

    Science.gov (United States)

    Guyton, J. R.; Klemp, K. F.

    1992-01-01

    Subendothelial accumulation of extracellular liposomes rich in unesterified cholesterol has been described as an early feature of atherosclerosis induced by cholesterol feeding in rabbits. Beta-very-low-density lipoproteins, however, the presumed source of atherogenic lipid in this animal model, contain mostly esterified cholesterol. The purpose of this study was to test for the presence of extracellular neutral lipid deposits consistent with esterified cholesterol, by employing new electron microscopic techniques. Rabbits were fed 0.5% cholesterol, 5% butter for 0, 1, 2, and 4 weeks. The lipid-preserving ultrastructural techniques showed, in control and atherosclerotic rabbit arteries, neutral lipid droplets adherent to the endothelial luminal surface. After 1 to 2 weeks, subendothelial extracellular deposits of mostly membranous lipid appeared; these deposits contained variable amounts of neutral lipid. At the same time, cytoplasmic neutral lipid droplets appeared in smooth muscle cells and in a small number of subendothelial macrophagelike cells. After 4 weeks, monocytic infiltration and macrophage foam cell development were prominent, but abundant extracellular lipid deposits also were found. Therefore, in arteries of cholesterol-fed rabbits, deposition of membranous and neutral lipid in the extracellular space and neutral lipid accumulation in resident arterial cells are early and probably independent events, both occurring before monocytic infiltration of the arterial intima. Images Figure 2 Figure 3 Figure 4 Figure 5 Figure 6 Figure 7 Figure 8 Figure 9 Figure 10 Figure 11 PMID:1415485

  13. Experimental Models of Foamy Macrophages and Approaches for Dissecting the Mechanisms of Lipid Accumulation and Consumption during Dormancy and Reactivation of Tuberculosis

    Science.gov (United States)

    Santucci, Pierre; Bouzid, Feriel; Smichi, Nabil; Poncin, Isabelle; Kremer, Laurent; De Chastellier, Chantal; Drancourt, Michel; Canaan, Stéphane

    2016-01-01

    Despite a slight decline since 2014, tuberculosis (TB) remains the major deadly infectious disease worldwide with about 1.5 million deaths each year and with about one-third of the population being latently infected with Mycobacterium tuberculosis, the etiologic agent of TB. During primo-infection, the recruitment of immune cells leads to the formation of highly organized granulomas. Among the different cells, one outstanding subpopulation is the foamy macrophage (FM), characterized by the abundance of triacylglycerol-rich lipid bodies (LB). M. tuberculosis can reside in FM, where it acquires, from host LB, the neutral lipids which are subsequently processed and stored by the bacilli in the form of intracytosolic lipid inclusions (ILI). Although host LB can be viewed as a reservoir of nutrients for the pathogen during latency, the molecular mechanisms whereby intraphagosomal mycobacteria interact with LB and assimilate the LB-derived lipids are only beginning to be understood. Past studies have emphasized that these physiological processes are critical to the M. tuberculosis infectious-life cycle, for propagation of the infection, establishment of the dormancy state and reactivation of the disease. In recent years, several animal and cellular models have been developed with the aim of dissecting these complex processes and of determining the nature and contribution of their key players. Herein, we review some of the in vitro and in vivo models which allowed to gain significant insight into lipid accumulation and consumption in M. tuberculosis, two important events that are directly linked to pathogenicity, granuloma formation/maintenance and survival of the tubercle bacillus under non-replicative conditions. We also discuss the advantages and limitations of each model, hoping that this will serve as a guide for future investigations dedicated to persistence and innovative therapeutic approaches against TB. PMID:27774438

  14. HDL cholesterol: atherosclerosis and beyond

    NARCIS (Netherlands)

    Bochem, A.E.

    2013-01-01

    Cardiovascular disease (CVD) is the leading cause of death in the Western world. Myocardial infarction and stroke are the result of a compromised blood flow which may result from cholesterol accumulation in the vessel wall due to high plasma levels of LDL cholesterol. High plasma levels of HDL

  15. Genetic and Chemical Correction of Cholesterol Accumulation and Impaired Autophagy in Hepatic and Neural Cells Derived from Niemann-Pick Type C Patient-Specific iPS Cells

    Directory of Open Access Journals (Sweden)

    Dorothea Maetzel

    2014-06-01

    Full Text Available Niemann-Pick type C (NPC disease is a fatal inherited lipid storage disorder causing severe neurodegeneration and liver dysfunction with only limited treatment options for patients. Loss of NPC1 function causes defects in cholesterol metabolism and has recently been implicated in deregulation of autophagy. Here, we report the generation of isogenic pairs of NPC patient-specific induced pluripotent stem cells (iPSCs using transcription activator-like effector nucleases (TALENs. We observed decreased cell viability, cholesterol accumulation, and dysfunctional autophagic flux in NPC1-deficient human hepatic and neural cells. Genetic correction of a disease-causing mutation rescued these defects and directly linked NPC1 protein function to impaired cholesterol metabolism and autophagy. Screening for autophagy-inducing compounds in disease-affected human cells showed cell type specificity. Carbamazepine was found to be cytoprotective and effective in restoring the autophagy defects in both NPC1-deficient hepatic and neuronal cells and therefore may be a promising treatment option with overall benefit for NPC disease.

  16. Moderate alcohol consumption increases cholesterol efflux mediated by ABCA1

    NARCIS (Netherlands)

    Beulens, J.W.J.; Sierksma, A.; Tol, van A.; Fournier, C.

    2004-01-01

    Moderate alcohol consumption increases HDL cholesterol, which is involved in reverse cholesterol transport (RCT). The aim of this study was to investigate the effect of moderate alcohol consumption on cholesterol efflux, using J774 mouse macrophages and Fu5AH cells, and on other parameters in the RC

  17. Enhanced expression of hemoglobin scavenger receptor CD163 in accumulated macrophages within filtered debris between acute coronary syndromes and stable angina pectoris.

    Science.gov (United States)

    Sato, Takao; Kameyama, Tomoki; Noto, Takahisa; Ueno, Hiroshi; Inoue, Hiroshi

    2015-01-01

    Coronary intraplaque hemorrhage up-regulates hemoglobin scavenger receptor CD163 expression on macrophages, and has an association with vulnerable plaque development. During percutaneous coronary intervention, mechanical plaque disruption exposes potentially embolic atheromatous contents from culprit plaque.In 37 patients with stable angina pectoris (SAP, n = 20) or acute coronary syndrome (ACS, n = 17), atherothrombotic debris was collected using a filter-based distal embolic protection device. We immunohistochemically determined CD14-positive macrophages and CD163-positive macrophages in filtered debris. We also examined the relation of CD14- and CD163-positive macrophages with culprit plaque volume and components evaluated with ultrasonic tissue characterization (VH-IVUS).The only significant difference in clinical characteristics between the two groups was in hs-CRP. In ACS, the percentage of CD14- and CD163-positive macrophages to the whole cells (%CD14 and %CD163, respectively) was significantly higher than that in SAP (20.1 ± 8.2 versus 8.8 ± 6.8%, P CD163 had a significant positive correlation with %NC (%CD14: r = 0.40, P = 0.01 and %CD163: r = 0.45, P = 0.01), but only %CD163 was negatively correlated with %Fibrous (%CD163: r = -0.48, P = 0.01).These findings suggest that the presence of CD14- and CD163-positive macrophages may reflect plaque inflammation, NC expansion, and plaque vulnerability in patients with coronary heart disease.

  18. Good vs. Bad Cholesterol

    Science.gov (United States)

    ... Venous Thromboembolism Aortic Aneurysm More Good vs. Bad Cholesterol Updated:Apr 3,2017 Cholesterol can't dissolve ... test . View an animation of cholesterol . LDL (Bad) Cholesterol LDL cholesterol is considered the “bad” cholesterol because ...

  19. Cholesterol and Women's Health

    Science.gov (United States)

    ... cholesterol.” What is dyslipidemia? Having abnormal levels of cholesterol or triglycerides is called dyslipidemia . A common dyslipidemia in the ... the levels of total cholesterol, LDL cholesterol, HDL cholesterol, and triglycerides. When should my cholesterol levels be measured? Women ...

  20. High Blood Cholesterol

    Science.gov (United States)

    ... version of this page please turn Javascript on. High Blood Cholesterol What is High Blood Cholesterol? What is Cholesterol? Cholesterol is a ... heart disease. If Your Blood Cholesterol Is Too High Too much cholesterol in your blood is called ...

  1. Cholesterol metabolism in Huntington disease.

    Science.gov (United States)

    Karasinska, Joanna M; Hayden, Michael R

    2011-09-06

    The CNS is rich in cholesterol, which is essential for neuronal development and survival, synapse maturation, and optimal synaptic activity. Alterations in brain cholesterol homeostasis are linked to neurodegeneration. Studies have demonstrated that Huntington disease (HD), a progressive and fatal neurodegenerative disorder resulting from polyglutamine expansion in the huntingtin protein, is associated with changes in cellular cholesterol metabolism. Emerging evidence from human and animal studies indicates that attenuated brain sterol synthesis and accumulation of cholesterol in neuronal membranes represent two distinct mechanisms occurring in the presence of mutant huntingtin that influence neuronal survival. Increased knowledge of how changes in intraneuronal cholesterol metabolism influence the pathogenesis of HD will provide insights into the potential application of brain cholesterol regulation as a therapeutic strategy for this devastating disease.

  2. Interleukin 27 inhibits atherosclerosis via immunoregulation of macrophages in mice.

    Science.gov (United States)

    Hirase, Tetsuaki; Hara, Hiromitsu; Miyazaki, Yoshiyuki; Ide, Noriko; Nishimoto-Hazuku, Ai; Fujimoto, Hirokazu; Saris, Christiaan J M; Yoshida, Hiroki; Node, Koichi

    2013-08-01

    Chronic inflammation in arterial wall that is driven by immune cells and cytokines plays pivotal roles in the development of atherosclerosis. Interleukin 27 (IL-27) is a member of the IL-12 family of cytokines that consists of IL-27p28 and Epstein-Barr virus induced gene 3 (EBI3) and has anti-inflammatory properties that regulate T cell polarization and cytokine production. IL-27-deficient (Ldlr-/-Ebi3-/-) and IL-27 receptor-deficient (Ldlr-/-WSX-1-/-) Ldlr-/- mice were generated and fed with a high-cholesterol diet to induce atherosclerosis. Roles of bone marrow-derived cells in vivo and macrophages in vitro were studied using bone marrow reconstitution by transplantation and cultured peritoneal macrophages, respectively. We demonstrate that mice lacking IL-27 or IL-27 receptor are more susceptible to atherosclerosis compared with wild type due to enhanced accumulation and activation of macrophages in arterial walls. The number of circulating proinflammatory Ly6C(hi) monocytes showed no significant difference between wild-type mice and mice lacking IL-27 or IL-27 receptor. Administration of IL-27 suppressed the development of atherosclerosis in vivo and macrophage activation in vitro that was indicated by increased uptake of modified low-density lipoprotein and augmented production of proinflammatory cytokines. These findings define a novel inhibitory role for IL-27 in atherosclerosis that regulates macrophage activation in mice.

  3. Macrophage ABCG1 deletion disrupts lipid homeostasis in alveolar macrophages and moderately influences atherosclerotic lesion development in LDL receptor-deficient mice

    NARCIS (Netherlands)

    Out, Ruud; Hoekstra, Menno; Hildebrand, Reeni B.; Kruit, Janine K.; Meurs, Illiana; Li, Zhaosha; Kuipers, Folkert; Van Berkel, Theo J. C.; Van Eck, Miranda

    2006-01-01

    Objective - ABCG1 has recently been identified as a facilitator of cellular cholesterol and phospholipid efflux to high-density lipoprotein (HDL). Its expression in macrophages is induced during cholesterol uptake in macrophages and by liver X receptor (LXR). The role of macrophage ABCG1 in

  4. Cytotoxic cholesterol is generated by the hydrolysis of cytoplasmic cholesteryl ester and transported to the plasma membrane.

    Science.gov (United States)

    Kellner-Weibel, G; Geng, Y J; Rothblat, G H

    1999-10-01

    The present study examines the fate and effects of free cholesterol (FC) generated by the hydrolysis of cytoplasmic cholesteryl esters (CE) in model macrophage foam cells. J774 or elicited mouse peritoneal macrophages (MPM) were enriched with CE by incubating with acetylated low density lipoprotein (acLDL) and FC/phospholipid dispersions, thus creating model foam cells. Treatment of the foam cells with the acyl coenzyme-A:cholesterol acyltransferase (ACAT) inhibitor, CP-113,818, in the absence of any extracellular cholesterol acceptors, resulted in cellular toxicity. This was accompanied by an increase in the amount of FC available for oxidation by an exogenous cholesterol oxidase. Furthermore, cellular toxicity was proportional to the size of the oxidase susceptible pool of FC over time. Morphological analysis and in situ DNA fragmentation assay demonstrated the occurrence of apoptosis in the ACAT inhibited cells. Co-treatment with the hydrophobic amine U18666A, an intracellular cholesterol transport inhibitor, led to a dose dependent reduction in cytotoxicity and apoptosis, and blocked the movement of FC into the oxidase susceptible pool. In addition, treating model foam cells with CP-113,818 plus chloroquine, a compound that inhibits the function of acidic vesicles, also diminished cellular toxicity. Staining with the cholesterol binding dye filipin revealed that the macrophages treated with CP-113,818 contained a cholesterol oxidase accessible pool of FC in the plasma membrane. These results suggest that FC generated by the hydrolysis of cytoplasmic CE is transported through acidic vesicles to the plasma membrane, and accumulation of FC in this pool triggers cell death by necrosis and apoptosis.

  5. Imaging of macrophage-related lung diseases

    Energy Technology Data Exchange (ETDEWEB)

    Marten, Katharina; Hansell, David M. [Royal Brompton Hospital, Department of Radiology, London (United Kingdom)

    2005-04-01

    Macrophage-related pulmonary diseases are a heterogeneous group of disorders characterized by macrophage accumulation, activation or dysfunction. These conditions include smoking-related interstitial lung diseases, metabolic disorders such as Niemann-Pick or Gaucher disease, and rare primary lung tumors. High-resolution computed tomography abnormalities include pulmonary ground-glass opacification secondary to infiltration by macrophages, centrilobular nodules or interlobular septal thickening reflecting peribronchiolar or septal macrophage accumulation, respectively, emphysema caused by macrophage dysfunction, and honeycombing following macrophage-related lung matrix remodeling. (orig.)

  6. Atheroprotection through SYK inhibition fails in established disease when local macrophage proliferation dominates lesion progression.

    Science.gov (United States)

    Lindau, Alexandra; Härdtner, Carmen; Hergeth, Sonja P; Blanz, Kelly Daryll; Dufner, Bianca; Hoppe, Natalie; Anto-Michel, Nathaly; Kornemann, Jan; Zou, Jiadai; Gerhardt, Louisa M S; Heidt, Timo; Willecke, Florian; Geis, Serjosha; Stachon, Peter; Wolf, Dennis; Libby, Peter; Swirski, Filip K; Robbins, Clinton S; McPheat, William; Hawley, Shaun; Braddock, Martin; Gilsbach, Ralf; Hein, Lutz; von zur Mühlen, Constantin; Bode, Christoph; Zirlik, Andreas; Hilgendorf, Ingo

    2016-03-01

    Macrophages in the arterial intima sustain chronic inflammation during atherogenesis. Under hypercholesterolemic conditions murine Ly6C(high) monocytes surge in the blood and spleen, infiltrate nascent atherosclerotic plaques, and differentiate into macrophages that proliferate locally as disease progresses. Spleen tyrosine kinase (SYK) may participate in downstream signaling of various receptors that mediate these processes. We tested the effect of the SYK inhibitor fostamatinib on hypercholesterolemia-associated myelopoiesis and plaque formation in Apoe(-/-) mice during early and established atherosclerosis. Mice consuming a high cholesterol diet supplemented with fostamatinib for 8 weeks developed less atherosclerosis. Histologic and flow cytometric analysis of aortic tissue showed that fostamatinib reduced the content of Ly6C(high) monocytes and macrophages. SYK inhibition limited Ly6C(high) monocytosis through interference with GM-CSF/IL-3 stimulated myelopoiesis, attenuated cell adhesion to the intimal surface, and blocked M-CSF stimulated monocyte to macrophage differentiation. In Apoe(-/-) mice with established atherosclerosis, however, fostamatinib treatment did not limit macrophage accumulation or lesion progression despite a significant reduction in blood monocyte counts, as lesional macrophages continued to proliferate. Thus, inhibition of hypercholesterolemia-associated monocytosis, monocyte infiltration, and differentiation by SYK antagonism attenuates early atherogenesis but not established disease when local macrophage proliferation dominates lesion progression.

  7. PCSK9 at the crossroad of cholesterol metabolism and immune function during infections.

    Science.gov (United States)

    Paciullo, Francesco; Fallarino, Francesca; Bianconi, Vanessa; Mannarino, Massimo R; Sahebkar, Amirhossein; Pirro, Matteo

    2017-09-01

    Sepsis, a complex and dynamic syndrome resulting from microbial invasion and immune system dysregulation, is associated with an increased mortality, reaching up to 35% worldwide. Cholesterol metabolism is often disturbed during sepsis, with low plasma cholesterol levels being associated with poor prognosis. Proprotein convertase subtilisin/kexin type 9 (PCSK9) promotes degradation of the low-density lipoprotein receptor (LDLR), thus regulating intracellular and plasma cholesterol levels. PCSK9 is often upregulated during sepsis and might have a detrimental effect on immune host response and survival. Accordingly, PCSK9 reduces lipopolysaccharide uptake and clearance by human hepatocytes. Moreover, PCSK9 upregulation exacerbates organ dysfunction and tissue inflammation during sepsis, whereas a protective effect of PCSK9 deficiency has been documented in septic patients. Although a possible detrimental impact of PCSK9 on survival has been described, some beneficial effects of PCSK9 on immune response may be hypothesized. First, PCSK9 is associated with increased plasma cholesterol levels, which might be protective during sepsis. Second, PCSK9, by stimulating LDLR degradation and inhibiting reverse cholesterol transport (RCT), might promote preferential cholesterol accumulation in macrophages and other immune cells; these events might improve lipid raft composition and augment toll-like receptor function thus supporting inflammatory response. Hence, a more clear definition of the role of PCSK9 in septic states might provide additional insight in the understanding of the sepsis-associated immune dysregulation and enhance therapeutic outcomes. © 2017 Wiley Periodicals, Inc.

  8. T cell activation inhibitors reduce CD8+ T cell and pro-inflammatory macrophage accumulation in adipose tissue of obese mice.

    Directory of Open Access Journals (Sweden)

    Vince N Montes

    Full Text Available Adipose tissue inflammation and specifically, pro-inflammatory macrophages are believed to contribute to insulin resistance (IR in obesity in humans and animal models. Recent studies have invoked T cells in the recruitment of pro-inflammatory macrophages and the development of IR. To test the role of the T cell response in adipose tissue of mice fed an obesogenic diet, we used two agents (CTLA-4 Ig and anti-CD40L antibody that block co-stimulation, which is essential for full T cell activation. C57BL/6 mice were fed an obesogenic diet for 16 weeks, and concomitantly either treated with CTLA-4 Ig, anti-CD40L antibody or an IgG control (300 µg/week. The treatments altered the immune cell composition of adipose tissue in obese mice. Treated mice demonstrated a marked reduction in pro-inflammatory adipose tissue macrophages and activated CD8+ T cells. Mice treated with anti-CD40L exhibited reduced weight gain, which was accompanied by a trend toward improved IR. CTLA-4 Ig treatment, however, was not associated with improved IR. These data suggest that the presence of pro-inflammatory T cells and macrophages can be altered with co-stimulatory inhibitors, but may not be a significant contributor to the whole body IR phenotype.

  9. D38-cholesterol as a Raman active probe for imaging intracellular cholesterol storage

    Science.gov (United States)

    Alfonso-García, Alba; Pfisterer, Simon G.; Riezman, Howard; Ikonen, Elina; Potma, Eric O.

    2016-06-01

    We generated a highly deuterated cholesterol analog (D38-cholesterol) and demonstrated its use for selective vibrational imaging of cholesterol storage in mammalian cells. D38-cholesterol produces detectable signals in stimulated Raman scattering (SRS) imaging, is rapidly taken up by cells, and is efficiently metabolized by acyl-CoA cholesterol acyltransferase to form cholesteryl esters. Using hyperspectral SRS imaging of D38-cholesterol, we visualized cholesterol storage in lipid droplets. We found that some lipid droplets accumulated preferentially unesterified D38-cholesterol, whereas others stored D38-cholesteryl esters. In steroidogenic cells, D38-cholesteryl esters and triacylglycerols were partitioned into distinct sets of lipid droplets. Thus, hyperspectral SRS imaging of D38-cholesterol demonstrates a heterogeneous incorporation of neutral lipid species, i.e., free cholesterol, cholesteryl esters, and triacylglycerols, between individual lipid droplets in a cell.

  10. High Blood Cholesterol

    Science.gov (United States)

    ... page from the NHLBI on Twitter. What Is Cholesterol? To understand high blood cholesterol (ko-LES-ter- ... cholesterol from your body. What Is High Blood Cholesterol? High blood cholesterol is a condition in which ...

  11. Glutamine Modulates Macrophage Lipotoxicity

    Directory of Open Access Journals (Sweden)

    Li He

    2016-04-01

    Full Text Available Obesity and diabetes are associated with excessive inflammation and impaired wound healing. Increasing evidence suggests that macrophage dysfunction is responsible for these inflammatory defects. In the setting of excess nutrients, particularly dietary saturated fatty acids (SFAs, activated macrophages develop lysosome dysfunction, which triggers activation of the NLRP3 inflammasome and cell death. The molecular pathways that connect lipid stress to lysosome pathology are not well understood, but may represent a viable target for therapy. Glutamine uptake is increased in activated macrophages leading us to hypothesize that in the context of excess lipids glutamine metabolism could overwhelm the mitochondria and promote the accumulation of toxic metabolites. To investigate this question we assessed macrophage lipotoxicity in the absence of glutamine using LPS-activated peritoneal macrophages exposed to the SFA palmitate. We found that glutamine deficiency reduced lipid induced lysosome dysfunction, inflammasome activation, and cell death. Under glutamine deficient conditions mTOR activation was decreased and autophagy was enhanced; however, autophagy was dispensable for the rescue phenotype. Rather, glutamine deficiency prevented the suppressive effect of the SFA palmitate on mitochondrial respiration and this phenotype was associated with protection from macrophage cell death. Together, these findings reveal that crosstalk between activation-induced metabolic reprogramming and the nutrient microenvironment can dramatically alter macrophage responses to inflammatory stimuli.

  12. Lecithin:cholesterol acyltransferase: old friend or foe in atherosclerosis?

    Science.gov (United States)

    Kunnen, Sandra; Van Eck, Miranda

    2012-01-01

    Lecithin:cholesterol acyltransferase (LCAT) is a key enzyme that catalyzes the esterification of free cholesterol in plasma lipoproteins and plays a critical role in high-density lipoprotein (HDL) metabolism. Deficiency leads to accumulation of nascent preβ-HDL due to impaired maturation of HDL particles, whereas enhanced expression is associated with the formation of large, apoE-rich HDL1 particles. In addition to its function in HDL metabolism, LCAT was believed to be an important driving force behind macrophage reverse cholesterol transport (RCT) and, therefore, has been a subject of great interest in cardiovascular research since its discovery in 1962. Although half a century has passed, the importance of LCAT for atheroprotection is still under intense debate. This review provides a comprehensive overview of the insights that have been gained in the past 50 years on the biochemistry of LCAT, the role of LCAT in lipoprotein metabolism and the pathogenesis of atherosclerosis in animal models, and its impact on cardiovascular disease in humans. PMID:22566575

  13. Signal transduction pathways provide opportunities to enhance HDL and apoAI-dependent reverse cholesterol transport.

    Science.gov (United States)

    Mulay, Vishwaroop; Wood, Peta; Rentero, Carles; Enrich, Carlos; Grewal, Thomas

    2012-02-01

    Binding of High Density Lipoprotein (HDL) and its major apolipoprotein A-I (apoA-I) to cell surface receptors is believed to initiate a plethora of signaling cascades that promote atheroprotective cell behavior, including the removal of excess cholesterol from lipid-loaded macrophages. More specifically, HDL and apoA-I binding to scavenger receptor BI (SR-BI) and ATP-binding cassette (ABC) transporter A1 has been shown to activate protein kinase A and C (PKA, PKC), Rac/Rho GTPases, Janus Kinase 2 (JAK2), calmodulin as well as mitogen-activated protein kinases (MAPK). Some of these signaling events upregulate mobilization of cholesterol from cellular pools, while others promote efflux pathways through increased expression, stability, and cell surface localization of SR-BI and ABCA1. This review aims to summarize the current knowledge of HDL- and apoA-I -induced signal transduction pathways that are linked to cholesterol efflux and discusses the underlying mechanisms that could couple ligand binding to SR-BI and ABCA1 with signaling and cholesterol export. Additional focus is given on the potential of pharmacological intervention to modulate the activity of signaling cascades for the inhibition or regression of cholesterol accumulation in atherosclerotic lesions.

  14. Aspirin Prevention of Cholesterol Gallstone Formation in Prairie Dogs

    Science.gov (United States)

    Lee, Sum P.; Carey, Martin C.; Lamont, J. Thomas

    1981-03-01

    When prairie dogs (Cynomys ludovicianus) are fed a diet containing cholesterol, a marked increase in gallbladder mucin secretion parallels the evolution of cholesterol supersaturated bile. Gelation of mucin precedes the precipitation of cholesterol liquid and solid crystals and the development of gallstones. Aspirin given to prairie dogs inhibited mucin hypersecretion and gel accumulation and prevented gallstone formation without influencing the cholesterol content of supersaturated bile. This suggests that gallbladder mucin is a nucleation matrix for cholesterol gallstones.

  15. Aspirin prevention of cholesterol gallstone formation in prairie dogs.

    Science.gov (United States)

    Lee, S P; Carey, M C; LaMont, J T

    1981-03-27

    When prairie dogs (Cynomys ludovicianus) are fed a diet containing cholesterol, a marked increase in gallbladder mucin secretion parallels the evolution of cholesterol supersaturated bile. Gelation of mucin precedes the precipitation of cholesterol liquid and solid crystals and the development of gallstones. Aspirin given to prairie dogs inhibited mucin hypersecretion and gel accumulation and prevented gallstone formation without influencing the cholesterol content of supersaturated bile. This suggests that gallbladder mucin is a nucleation matrix for cholesterol gallstones.

  16. Vinpocetine attenuates lipid accumulation and atherosclerosis formation

    Energy Technology Data Exchange (ETDEWEB)

    Cai, Yujun [Aab Cardiovascular Research Institute, Department of Medicine, University of Rochester, 601 Elmwood Ave, Rochester, NY 14642 (United States); Li, Jian-Dong [Center for Inflammation, Immunity and Infection, and Department of Biology, Georgia State University, Atlanta, GA 30303 (United States); Yan, Chen, E-mail: Chen_Yan@urmc.rochester.edu [Aab Cardiovascular Research Institute, Department of Medicine, University of Rochester, 601 Elmwood Ave, Rochester, NY 14642 (United States)

    2013-05-10

    Highlights: •Vinpocetine attenuates hyperlipidemia-induced atherosclerosis in a mouse model. •Vinpocetine antagonizes ox-LDL uptake and accumulation in macrophages. •Vinpocetine blocks the induction of ox-LDL receptor LOX-1 in vitro and in vivo. -- Abstract: Atherosclerosis, the major cause of myocardial infarction and stroke, is a chronic arterial disease characterized by lipid deposition and inflammation in the vessel wall. Cholesterol, in low-density lipoprotein (LDL), plays a critical role in the pathogenesis of atherosclerosis. Vinpocetine, a derivative of the alkaloid vincamine, has long been used as a cerebral blood flow enhancer for treating cognitive impairment. Recent study indicated that vinpocetine is a potent anti-inflammatory agent. However, its role in the pathogenesis of atherosclerosis remains unexplored. In the present study, we show that vinpocetine significantly reduced atherosclerotic lesion formation in ApoE knockout mice fed with a high-fat diet. In cultured murine macrophage RAW264.7 cells, vinpocetine markedly attenuated oxidized LDL (ox-LDL) uptake and foam cell formation. Moreover, vinpocetine greatly blocked the induction of ox-LDL receptor 1 (LOX-1) in cultured macrophages as well as in the LOX-1 level in atherosclerotic lesions. Taken together, our data reveal a novel role of vinpocetine in reduction of pathogenesis of atherosclerosis, at least partially through suppressing LOX-1 signaling pathway. Given the excellent safety profile of vinpocetine, this study suggests vinpocetine may be a therapeutic candidate for treating atherosclerosis.

  17. Women and Cholesterol

    Science.gov (United States)

    ... Disease Venous Thromboembolism Aortic Aneurysm More Women and Cholesterol Updated:Apr 1,2016 The female sex hormone ... 2014. Related Sites Nutrition Center My Life Check Cholesterol • Home • About Cholesterol • Why Cholesterol Matters • Understand Your ...

  18. HDL Cholesterol Test

    Science.gov (United States)

    ... products and services. Advertising & Sponsorship: Policy | Opportunities HDL Cholesterol Share this page: Was this page helpful? Also ... HDL; HDL-C Formal name: High-density Lipoprotein Cholesterol Related tests: Cholesterol ; LDL Cholesterol ; Triglycerides ; Lipid Profile ; ...

  19. Cholesterol IQ Quiz

    Science.gov (United States)

    ... Peripheral Artery Disease Venous Thromboembolism Aortic Aneurysm More Cholesterol IQ Quiz Updated:Feb 2,2015 Begin the quiz Cholesterol • Home • About Cholesterol Introduction Good vs. Bad Cholesterol ...

  20. Cholesterol and Your Child

    Science.gov (United States)

    ... Old Feeding Your 1- to 2-Year-Old Cholesterol and Your Child KidsHealth > For Parents > Cholesterol and ... child's risk of developing heart disease later. About Cholesterol Cholesterol is a waxy substance produced by the ...

  1. Lifestyle Changes and Cholesterol

    Science.gov (United States)

    ... Venous Thromboembolism Aortic Aneurysm More Lifestyle Changes and Cholesterol Updated:Sep 26,2016 As part of a ... to the Terms and Conditions and Privacy Policy Cholesterol • Home • About Cholesterol • Why Cholesterol Matters • Understand Your ...

  2. Common Misconceptions about Cholesterol

    Science.gov (United States)

    ... Venous Thromboembolism Aortic Aneurysm More Common Misconceptions about Cholesterol Updated:Apr 3,2017 Cholesterol can be both ... misconceptions about cholesterol. Click on each misconception about cholesterol to see the truth: My choices about diet ...

  3. Cellular Cholesterol Regulates Ubiquitination and Degradation of the Cholesterol Export Proteins ABCA1 and ABCG1*

    Science.gov (United States)

    Hsieh, Victar; Kim, Mi-Jurng; Gelissen, Ingrid C.; Brown, Andrew J.; Sandoval, Cecilia; Hallab, Jeannette C.; Kockx, Maaike; Traini, Mathew; Jessup, Wendy; Kritharides, Leonard

    2014-01-01

    The objective of this study was to examine the influence of cholesterol in post-translational control of ABCA1 and ABCG1 protein expression. Using CHO cell lines stably expressing human ABCA1 or ABCG1, we observed that the abundance of these proteins is increased by cell cholesterol loading. The response to increased cholesterol is rapid, is independent of transcription, and appears to be specific for these membrane proteins. The effect is mediated through cholesterol-dependent inhibition of transporter protein degradation. Cell cholesterol loading similarly regulates degradation of endogenously expressed ABCA1 and ABCG1 in human THP-1 macrophages. Turnover of ABCA1 and ABCG1 is strongly inhibited by proteasomal inhibitors and is unresponsive to inhibitors of lysosomal proteolysis. Furthermore, cell cholesterol loading inhibits ubiquitination of ABCA1 and ABCG1. Our findings provide evidence for a rapid, cholesterol-dependent, post-translational control of ABCA1 and ABCG1 protein levels, mediated through a specific and sterol-sensitive mechanism for suppression of transporter protein ubiquitination, which in turn decreases proteasomal degradation. This provides a mechanism for acute fine-tuning of cholesterol transporter activity in response to fluctuations in cell cholesterol levels, in addition to the longer term cholesterol-dependent transcriptional regulation of these genes. PMID:24500716

  4. Obesity, cholesterol metabolism, and breast cancer pathogenesis.

    Science.gov (United States)

    McDonnell, Donald P; Park, Sunghee; Goulet, Matthew T; Jasper, Jeff; Wardell, Suzanne E; Chang, Ching-Yi; Norris, John D; Guyton, John R; Nelson, Erik R

    2014-09-15

    Obesity and altered lipid metabolism are risk factors for breast cancer in pre- and post-menopausal women. These pathologic relationships have been attributed in part to the impact of cholesterol on the biophysical properties of cell membranes and to the influence of these changes on signaling events initiated at the membrane. However, more recent studies have indicated that the oxysterol 27-hydroxycholesterol (27HC), and not cholesterol per se, may be the primary biochemical link between lipid metabolism and cancer. The enzyme responsible for production of 27HC from cholesterol, CYP27A1, is expressed primarily in the liver and in macrophages. In addition, significantly elevated expression of this enzyme within breast tumors has also been observed. It is believed that 27HC, acting through the liver X receptor in macrophages and possibly other cells, is involved in maintaining organismal cholesterol homeostasis. It has also been shown recently that 27HC is an estrogen receptor agonist in breast cancer cells and that it stimulates the growth and metastasis of tumors in several models of breast cancer. These findings provide the rationale for the clinical evaluation of pharmaceutical approaches that interfere with cholesterol/27HC synthesis as a means to mitigate the impact of cholesterol on breast cancer pathogenesis. Cancer Res; 74(18); 4976-82. ©2014 AACR. ©2014 American Association for Cancer Research.

  5. Obesity, Cholesterol Metabolism and Breast Cancer Pathogenesis

    Science.gov (United States)

    McDonnell, Donald P.; Park, Sunghee; Goulet, Matthew T.; Jasper, Jeff; Wardell, Suzanne E.; Chang, Ching-yi; Norris, John D.; Guyton, John R.; Nelson, Erik R.

    2014-01-01

    Obesity and altered lipid metabolism are risk factors for breast cancer in pre- and post-menopausal women. These pathologic relationships have been attributed in part to the impact of cholesterol on the biophysical properties of cell membranes and to the influence of these changes on signaling events initiated at the membrane. However, more recent studies have indicated that the oxysterol 27-hydroxycholesterol (27HC), and not cholesterol per se, may be the primary biochemical link between lipid metabolism and cancer. The enzyme responsible for production of 27HC from cholesterol, CYP27A1, is expressed primarily in the liver and in macrophages. In addition significantly elevated expression of this enzyme within breast tumors has also been observed. It is believed that 27HC, acting through the liver X receptor (LXR) in macrophages and possibly other cells is involved in maintaining organismal cholesterol homeostasis. It has also been shown recently that 27HC is an estrogen receptor (ER) agonist in breast cancer cells and that it stimulates the growth and metastasis of tumors in several models of breast cancer. These findings provide the rationale for the clinical evaluation of pharmaceutical approaches that interfere with cholesterol/27HC synthesis as a means to mitigate the impact of cholesterol on breast cancer pathogenesis. PMID:25060521

  6. What Is Cholesterol?

    Science.gov (United States)

    ... Loss Surgery? A Week of Healthy Breakfasts Shyness Cholesterol KidsHealth > For Teens > Cholesterol Print A A A ... High Cholesterol? en español ¿Qué es el colesterol? Cholesterol Is a Fat in the Blood Cholesterol (kuh- ...

  7. What Is Cholesterol?

    Science.gov (United States)

    ... Loss Surgery? A Week of Healthy Breakfasts Shyness Cholesterol KidsHealth > For Teens > Cholesterol A A A What's ... High Cholesterol? en español ¿Qué es el colesterol? Cholesterol Is a Fat in the Blood Cholesterol (kuh- ...

  8. Acrolein increases macrophage atherogenicity in association with gut microbiota remodeling in atherosclerotic mice: protective role for the polyphenol-rich pomegranate juice.

    Science.gov (United States)

    Rom, Oren; Korach-Rechtman, Hila; Hayek, Tony; Danin-Poleg, Yael; Bar, Haim; Kashi, Yechezkel; Aviram, Michael

    2016-09-30

    The unsaturated aldehyde acrolein is pro-atherogenic, and the polyphenol-rich pomegranate juice (PJ), known for its anti-oxidative/anti-atherogenic properties, inhibits macrophage foam cell formation, the hallmark feature of early atherosclerosis. This study aimed to investigate two unexplored areas of acrolein atherogenicity: macrophage lipid metabolism and the gut microbiota composition. The protective effects of PJ against acrolein atherogenicity were also evaluated. Atherosclerotic apolipoprotein E-deficient (apoE(-/-)) mice that were fed acrolein (3 mg/kg/day) for 1 month showed significant increases in serum and aortic cholesterol, triglycerides, and lipid peroxides. In peritoneal macrophages isolated from the mice and in J774A.1 cultured macrophages, acrolein exposure increased intracellular oxidative stress and stimulated cholesterol and triglyceride accumulation via enhanced rates of their biosynthesis and over-expression of key regulators of cellular lipid biosynthesis: sterol regulatory element-binding proteins (SREBPs), 3-hydroxy-3-methyl-glutaryl-CoA reductase (HMGCR), and diacylglycerol acyltransferase1 (DGAT1). Acrolein-fed mice demonstrated a major shift in the gut microbiota composition, including a significant phylum-level change in increased Firmicutes and decreased Bacteroidetes. At the family level, acrolein significantly increased the prevalence of Ruminococcaceae and Lachnospiraceae of which the Coprococcus genus was significantly and positively correlated with serum, aortic and macrophage lipid levels and peroxidation. The pro-atherogenic effects of acrolein on serum, aortas, macrophages, and the gut microbiota were substantially abolished by PJ. In conclusion, these findings provide novel mechanisms by which acrolein increases macrophage lipid accumulation and alters the gut microbiota composition in association with enhanced atherogenesis. Moreover, PJ was found as an effective strategy against acrolein atherogenicity.

  9. Bone marrow-derived and peritoneal macrophages have different inflammatory response to oxLDL and M1/M2 marker expression – implications for atherosclerosis research

    Science.gov (United States)

    Bisgaard, Line S.; Mogensen, Christina K.; Rosendahl, Alexander; Cucak, Helena; Nielsen, Lars Bo; Rasmussen, Salka E.; Pedersen, Tanja X.

    2016-01-01

    Macrophages are heterogeneous and can polarize into specific subsets, e.g. pro-inflammatory M1-like and re-modelling M2-like macrophages. To determine if peritoneal macrophages (PEMs) or bone marrow derived macrophages (BMDMs) resembled aortic macrophages from ApoE−/− mice, their M1/M2 phenotype, inflammatory status, and lipid metabolism signatures were compared. oxLDL accumulation was similar in PEMs and BMDMs. On protein expression level, BMDMs showed an M2-like CD206highCD11clow profile, while cholesterol loading led to enhanced CD11c expression and reduced MCP-1 secretion. In contrast, PEMs expressed low levels of CD206 and CD11c, and responded to cholesterol loading by increasing CD11c expression and MCP-1 secretion. mRNA expression of M1/M2 markers was higher in PEMS than BMDMs, while lipid metabolism genes were similarly expressed. Whole aorta flow cytometry showed an accumulation of M2-like CD206highCD11clow macrophages in advanced versus early atherosclerotic disease in ApoE−/− mice. In isolated lesions, mRNA levels of the M2 markers Socs2, CD206, Retnla, and IL4 were downregulated with increasing disease severity. Likewise, mRNA expression of lipid metabolism genes (SREBP2, ACSL1, SRB1, DGAT1, and cpt1a) was decreased in advanced versus early lesions. In conclusion, PEMs and BMDMs are phenotypically distinct and differ from macrophages in lesions with respect to expression of M1/M2 markers and lipid metabolism genes. PMID:27734926

  10. Cholesterol efflux via ATP-binding cassette transporter A1 (ABCA1) and cholesterol uptake via the LDL receptor influences cholesterol-induced impairment of beta cell function in mice

    NARCIS (Netherlands)

    Kruit, J. K.; Kremer, P. H. C.; Dai, L.; Tang, R.; Ruddle, P.; de Haan, W.; Brunham, L. R.; Verchere, C. B.; Hayden, M. R.

    2010-01-01

    Cellular cholesterol accumulation is an emerging mechanism for beta cell dysfunction in type 2 diabetes. Absence of the cholesterol transporter ATP-binding cassette transporter A1 (ABCA1) results in increased islet cholesterol and impaired insulin secretion, indicating that impaired cholesterol effl

  11. Identification of an Autophagy Defect in Smokers’ Alveolar Macrophages1

    OpenAIRE

    2010-01-01

    Alveolar macrophages are essential for clearing bacteria from the alveolar surface and preventing microbial-induced infections. It is well documented that smokers have an increased incidence of infections, in particular lung infections. Alveolar macrophages accumulate in smokers’ lungs but they have a functional immune deficit. In this study, we identify for the first time an autophagy defect in smokers’ alveolar macrophages. Smokers’ alveolar macrophages accumulate both autophagosomes and p6...

  12. Copper induces the expression of cholesterogenic genes in human macrophages.

    Science.gov (United States)

    Svensson, Per Arne; Englund, Mikael C O; Markström, Emilia; Ohlsson, Bertil G; Jernås, Margareta; Billig, Håkan; Torgerson, Jarl S; Wiklund, Olov; Carlsson, Lena M S; Carlsson, Björn

    2003-07-01

    Accumulation of lipids and cholesterol by macrophages and subsequent transformation into foam cells are key features in development of atherosclerosis. Serum copper concentrations have been shown to be associated with cardiovascular disease. However, the mechanism behind the proatherogenic effect of copper is not clear. We used DNA microarrays to define the changes in gene expression profile in response to copper exposure of human macrophages. Expression monitoring by DNA microarray revealed 91 genes that were regulated. Copper increased the expression of seven cholesterogenic genes (3-hydroxy-3-methylglutaryl coenzyme A (HMG CoA) synthase, IPP isomerase, squalene synthase, squalene epoxidase, methyl sterol oxidase, H105e3 mRNA and sterol-C5-desaturase) and low-density lipoprotein receptor (LDL-R), and decreased the expression of CD36 and lipid binding proteins. The expression of LDL-R and HMG CoA reductase was also investigated using real time PCR. The expression of both of these genes was increased after copper treatment of macrophages (Pmechanism for the association between copper and atherosclerosis. The effect of copper on cholesterogenic genes may also have implications for liver steatosis in early stages of Wilson's disease.

  13. Imbalanced cholesterol metabolism in Alzheimer's disease.

    Science.gov (United States)

    Xue-shan, Zhao; Juan, Peng; Qi, Wu; Zhong, Ren; Li-hong, Pan; Zhi-han, Tang; Zhi-sheng, Jiang; Gui-xue, Wang; Lu-shan, Liu

    2016-05-01

    Alzheimer's disease (AD) is a complex and multifactorial neurodegenerative disease that is mainly caused by β-amyloid accumulation. A large number of studies have shown that elevated cholesterol levels may perform a function in AD pathology, and several cholesterol-related gene polymorphisms are associated with this disease. Although numerous studies have shown the important function of cholesterol in AD pathogenesis and development, the underlying mechanism remains unclear. To further elucidate cholesterol metabolism disorder and AD, we first, review metabolism and regulation of the cholesterol in the brain. Second, we summarize the literature stating that hypercholesterolemia is one of the risk factors of AD. Third, we discuss the main mechanisms of abnormal cholesterol metabolism that increase the risk of AD. Finally, the relationships between AD and apolipoprotein E, PCSK9, and LRP1 are discussed in this article.

  14. Cholesterol Facts and Statistics

    Science.gov (United States)

    ... Blood Pressure Salt Million Hearts® WISEWOMAN Program High Cholesterol Facts Recommend on Facebook Tweet Share Compartir As ... the facts about high cholesterol [PDF-281K] . High Cholesterol in the United States 73.5 million adults ( ...

  15. Get Your Cholesterol Checked

    Science.gov (United States)

    ... Checked Print This Topic En español Get Your Cholesterol Checked Browse Sections The Basics Overview Cholesterol Test ... How often do I need to get my cholesterol checked? The general recommendation is to get your ...

  16. Dietary Fat and Cholesterol

    Science.gov (United States)

    ... Conditions Nutrition & Fitness Emotional Health Dietary Fat and Cholesterol Posted under Health Guides . Updated 7 March 2017. + ... saturated fat found in red meat. What is cholesterol? Cholesterol is a fatlike substance that’s found in ...

  17. Causes of High Cholesterol

    Science.gov (United States)

    ... Venous Thromboembolism Aortic Aneurysm More Causes of High Cholesterol Updated:Jul 5,2017 If you have high ... and procedures related to heart disease and stroke. Cholesterol • Home • About Cholesterol • HDL, LDL, and Triglycerides • Causes ...

  18. High Blood Cholesterol Prevention

    Science.gov (United States)

    ... Million Hearts® WISEWOMAN Program Prevention and Management of High LDL Cholesterol: What You Can Do Recommend on ... like eating a healthy diet, can help prevent high cholesterol. High low-density lipoprotein (LDL) cholesterol increases ...

  19. Common Misconceptions about Cholesterol

    Science.gov (United States)

    ... Peripheral Artery Disease Venous Thromboembolism Aortic Aneurysm More Common Misconceptions about Cholesterol Updated:Jul 5,2017 How ... do you know about cholesterol? Here are some common misconceptions — and the truth. High cholesterol isn’t ...

  20. Cholesterol lowering, low cholesterol, and mortality.

    Science.gov (United States)

    LaRosa, J C

    1993-10-01

    Cholesterol lowering in both primary and secondary prevention has been clearly demonstrated to lower coronary morbidity and, in secondary prevention, to lower coronary mortality as well. Putative dangers of cholesterol lowering remain unproven. Population studies linking low cholesterol to noncoronary mortalities do not demonstrate cause-and-effect relations. In fact, based on current studies, the opposite is more likely to be the case. Neither gender nor age should automatically exclude persons from cholesterol screening. Drug intervention, however, should be used conservatively, particularly in young adults and the elderly. Drugs should be used only after diet and lifestyle interventions have failed. The evidence linking high blood cholesterol to coronary atherosclerosis and cholesterol lowering to its prevention is broad-based and definitive. Concerns about cholesterol lowering and spontaneously low cholesterols should be pursued but should not interfere with the implementation of current public policies to reduce the still heavy burden of atherosclerosis in Western society.

  1. Bone marrow angiotensin AT2 receptor deficiency aggravates atherosclerosis development by eliminating macrophage liver X receptor-mediated anti-atherogenic actions.

    Science.gov (United States)

    Kato, Taku; Kawahito, Hiroyuki; Kishida, Sou; Irie, Daisuke; Wakana, Noriyuki; Kikai, Masakazu; Takata, Hiroki; Ogata, Takehiro; Ueyama, Tomomi; Matoba, Satoaki; Yamada, Hiroyuki

    2015-12-01

    Bone marrow (BM) Angiotensin II (Ang II) type 1 (AT1) receptor plays a crucial role in atherosclerosis development; however, the effect of BM Ang II type 2 (AT2) receptor on atherogenesis remains undefined. We generated BM chimera apoE-deficient (apoE(-/-)) mice whose BM cells were repopulated with AT2-deficient (Agtr2(-/-)) or wild-type (Agtr2(+/+)) cells. After 2 months of a high-cholesterol diet, the atherosclerotic lesion area was significantly increased in the apoE(-/-)/BM-Agtr2(-/-) mice compared with the apoE(-/-)/BM-Agtr2(+/+) mice (51%, P < 0.05), accompanied by an augmented accumulation of lesion macrophages. Although phenotypic polarization in BM-derived macrophages and lipopolysaccharide-induced expression of proinflammatory cytokines in thioglycollate-induced peritoneal macrophages (TGPMs) were not affected by AT2-deficiency, mRNA and protein expression levels of macrophage liver X receptor β (LXRβ) were significantly decreased in Agtr2(-/-) TGPMs compared with Agtr2(+/+) TGPMs. Anti-inflammatory effects of LXR agonist (GW3965) were markedly inhibited in Agtr2(-/-) TGPMs. Furthermore, the expression levels of ATP-binding cassette transporter ABCA1 and CCR7 were much lower in Agtr2(-/-) TGPMs than Agtr2(+/+) TGPMs, accompanied by a significantly reduced cholesterol efflux. Our findings demonstrate that BM-AT2 deficiency aggravates atherosclerosis, at least in part, by eliminating the anti-atherogenic properties of macrophages elicited by LXRβ activation. © The Author(s) 2014.

  2. Critical role of neutral cholesteryl ester hydrolase 1 in cholesteryl ester hydrolysis in murine macrophages[S

    Science.gov (United States)

    Sakai, Kent; Igarashi, Masaki; Yamamuro, Daisuke; Ohshiro, Taichi; Nagashima, Shuichi; Takahashi, Manabu; Enkhtuvshin, Bolormaa; Sekiya, Motohiro; Okazaki, Hiroaki; Osuga, Jun-ichi; Ishibashi, Shun

    2014-01-01

    Hydrolysis of intracellular cholesteryl ester (CE) is the rate-limiting step in the efflux of cholesterol from macrophage foam cells. In mouse peritoneal macrophages (MPMs), this process is thought to involve several enzymes: hormone-sensitive lipase (Lipe), carboxylesterase 3 (Ces3), neutral CE hydrolase 1 (Nceh1). However, there is some disagreement over the relative contributions of these enzymes. To solve this problem, we first compared the abilities of several compounds to inhibit the hydrolysis of CE in cells overexpressing Lipe, Ces3, or Nceh1. Cells overexpressing Ces3 had negligible neutral CE hydrolase activity. We next examined the effects of these inhibitors on the hydrolysis of CE and subsequent cholesterol trafficking in MPMs. CE accumulation was increased by a selective inhibitor of Nceh1, paraoxon, and two nonselective inhibitors of Nceh1, (+)-AS115 and (−)-AS115, but not by two Lipe-selective inhibitors, orlistat and 76-0079. Paraoxon inhibited cholesterol efflux to apoA-I or HDL, while 76-0079 did not. These results suggest that Nceh1 plays a dominant role over Lipe in the hydrolysis of CE and subsequent cholesterol efflux in MPMs. PMID:24868095

  3. Histone deacetylase inhibition decreases cholesterol levels in neuronal cells by modulating key genes in cholesterol synthesis, uptake and efflux.

    Directory of Open Access Journals (Sweden)

    Maria João Nunes

    Full Text Available Cholesterol is an essential component of the central nervous system and increasing evidence suggests an association between brain cholesterol metabolism dysfunction and the onset of neurodegenerative disorders. Interestingly, histone deacetylase inhibitors (HDACi such as trichostatin A (TSA are emerging as promising therapeutic approaches in neurodegenerative diseases, but their effect on brain cholesterol metabolism is poorly understood. We have previously demonstrated that HDACi up-regulate CYP46A1 gene transcription, a key enzyme in neuronal cholesterol homeostasis. In this study, TSA was shown to modulate the transcription of other genes involved in cholesterol metabolism in human neuroblastoma cells, namely by up-regulating genes that control cholesterol efflux and down-regulating genes involved in cholesterol synthesis and uptake, thus leading to an overall decrease in total cholesterol content. Furthermore, co-treatment with the amphipathic drug U18666A that can mimic the intracellular cholesterol accumulation observed in cells of Niemman-Pick type C patients, revealed that TSA can ameliorate the phenotype induced by pathological cholesterol accumulation, by restoring the expression of key genes involved in cholesterol synthesis, uptake and efflux and promoting lysosomal cholesterol redistribution. These results clarify the role of TSA in the modulation of neuronal cholesterol metabolism at the transcriptional level, and emphasize the idea of HDAC inhibition as a promising therapeutic tool in neurodegenerative disorders with impaired cholesterol metabolism.

  4. PPARy phosphorylation mediated by JNK MAPK: a potential role in macrophage-derived foam cell formation

    Institute of Scientific and Technical Information of China (English)

    Ran YIN; Yu-gang DONG; Hong-lang LI

    2006-01-01

    Aim: To investigate whether oxidized low-density lipoprotein (ox-LDL) modulates peroxisome proliferator-activated receptor γ (PPARγ) activity through phosphorylation in macrophages, and the effect of PPARy phosphorylation on macrophages-derived foam cell formation. Methods: After exposing the cultured THP-1 cells to ox-LDL in the presence or absence of different mitogen-activated protein kinase (MAPK) inhibitors, PPARγ and phosphorylated PPARγ protein levels were detected by Western blot. MAPK activity was analyzed using MAP Kinase Assay Kit. Intracellular cholesterol accumulation was assessed by Oil red O staining and cholesterol oxidase enzymatic method. The Mrna level of PPARγ target gene was determined by reverse transcription-polymerase chain reaction (RT-PCR). Results: ox-LDL evaluated PPARγ phosphorylation status and subsequently decreased PPARγ target gene expression in a dose-dependent manner. Ox-LDL also induced MAPK activation. Treatment of THP-1 cells with c-Jun N-terminal kinase-, but not p38- or extracellular signal-regulated kinase-MAPK inhibitor, significantly suppressed PPARγ phosphorylation induced by ox-LDL, which in turn inhibited foam cell formation. Conclusion: In addition to its ligand-dependent activation, ox-LDL modulates PPARγ activity through phosphorylation, which is mediated by MAPK activation. PPARγ phosphorylation mediated by MAPK facilitates foam cell formation from macrophages exposed to ox-LDL.

  5. HDL Cholesterol: How to Boost Your 'Good' Cholesterol

    Science.gov (United States)

    HDL cholesterol: How to boost your 'good' cholesterol Your cholesterol levels are an important measure of heart health. For HDL cholesterol, or "good" cholesterol, higher levels are better. By Mayo Clinic ...

  6. The inhibition of macrophage foam cell formation by 9-cis β-carotene is driven by BCMO1 activity.

    Directory of Open Access Journals (Sweden)

    Noa Zolberg Relevy

    Full Text Available Atherosclerosis is a major cause of morbidity and mortality in developed societies, and begins when activated endothelial cells recruit monocytes and T-cells from the bloodstream into the arterial wall. Macrophages that accumulate cholesterol and other fatty materials are transformed into foam cells. Several epidemiological studies have demonstrated that a diet rich in carotenoids is associated with a reduced risk of heart disease; while previous work in our laboratory has shown that the 9-cis β-carotene rich alga Dunaliella inhibits atherogenesis in mice. The effect of 9-cis β-carotene on macrophage foam cell formation has not yet been investigated. In the present work, we sought to study whether the 9-cis β-carotene isomer, isolated from the alga Dunaliella, can inhibit macrophage foam cell formation upon its conversion to retinoids. The 9-cis β-carotene and Dunaliella lipid extract inhibited foam cell formation in the RAW264.7 cell line, similar to 9-cis retinoic acid. Furthermore, dietary enrichment with the algal powder in mice resulted in carotenoid accumulation in the peritoneal macrophages and in the inhibition of foam cell formation ex-vivo and in-vivo. We also found that the β-carotene cleavage enzyme β-carotene 15,15'-monooxygenase (BCMO1 is expressed and active in macrophages. Finally, 9-cis β-carotene, as well as the Dunaliella extract, activated the nuclear receptor RXR in hepa1-6 cells. These results indicate that dietary carotenoids, such as 9-cis β-carotene, accumulate in macrophages and can be locally cleaved by endogenous BCMO1 to form 9-cis retinoic acid and other retinoids. Subsequently, these retinoids activate the nuclear receptor RXR that, along with additional nuclear receptors, can affect various metabolic pathways, including those involved in foam cell formation and atherosclerosis.

  7. Cooking for Lower Cholesterol

    Science.gov (United States)

    ... Venous Thromboembolism Aortic Aneurysm More Cooking for Lower Cholesterol Updated:Oct 28,2016 A heart-healthy eating ... content was last reviewed on 04/21/2014. Cholesterol • Home • About Cholesterol • Why Cholesterol Matters • Understand Your ...

  8. Enhancement of human ACAT1 gene expression to promote the macrophage-derived foam cell formation by dexamethasone

    Institute of Scientific and Technical Information of China (English)

    Li YANG; Ta Yuan CHANG; Bo Liang LI; Jin Bo YANG; Jia CHEN; Guang Yao YU; Pei ZHOU; Lei LEI; Zhen Zhen WANG; Catherine CY CHANG; XinYing YANG

    2004-01-01

    In macrophages, the accumulation of cholesteryl esters synthesized by the activated acyl-coenzyme A:cholesterol acyltransferase-1 (ACAT1) results in the foam cell formation, a hallmark of early atherosclerotic lesions. In this study,with the treatment of a glucocorticoid hormone dexamethasone (Dex), lipid staining results clearly showed the large accumulation of lipid droplets containing cholesteryl esters in THP- 1-derived macrophages exposed to lower concentration of the oxidized low-density lipoprotein (ox-LDL). More notably, when treated together with specific anti-ACAT inhibitors, the abundant cholesteryl ester accumulation was markedly diminished in THP-l-derived macrophages, confirming that ACAT is the key enzyme responsible for intracellular cholesteryl ester synthesis. RT-PCR and Western blot results indicated that Dex caused up-regulation of human ACAT1 expression at both the mRNA and protein levels in THP-1 and THP- 1-derived macrophages. The luciferase activity assay demonstrated that Dex could enhance the activity of human ACAT1 gene P1 promoter, a major factor leading to the ACAT1 activation, in a cell-specific manner.Further experimental evidences showed that a glucocorticoid response element (GRE) located within human ACAT1gene P1 promoter to response to the elevation of human ACAT1 gene expression by Dex could be functionally bound with glucocorticoid receptor (GR) proteins. These data supported the hypothesis that the clinical treatment with Dex,which increased the incidence of atherosclerosis, may in part due to enhancing the ACAT1 expression to promote the accumulation of cholesteryl esters during the macrophage-derived foam cell formation, an early stage of atherosclerosis.

  9. E17110 promotes reverse cholesterol transport with liver X receptor β agonist activity in vitro

    Directory of Open Access Journals (Sweden)

    Ni Li

    2016-05-01

    Full Text Available Liver X receptor (LXR plays an important role in reverse cholesterol transport (RCT, and activation of LXR could reduce atherosclerosis. In the present study we used a cell-based screening method to identify new potential LXRβ agonists. A novel benzofuran-2-carboxylate derivative was identified with LXRβ agonist activity: E17110 showed a significant activation effect on LXRβ with an EC50 value of 0.72 μmol/L. E17110 also increased the expression of ATP-binding cassette transporter A1 (ABCA1 and G1 (ABCG1 in RAW264.7 macrophages. Moreover, E17110 significantly reduced cellular lipid accumulation and promoted cholesterol efflux in RAW264.7 macrophages. Interestingly, we found that the key amino acids in the LXRβ ligand-binding domain had distinct interactions with E17110 as compared to TO901317. These results suggest that E17110 was identified as a novel compound with LXRβ agonist activity in vitro via screening, and could be developed as a potential anti-atherosclerotic lead compound.

  10. Reverse cholesterol transport revisited

    Institute of Scientific and Technical Information of China (English)

    Astrid; E; van; der; Velde

    2010-01-01

    Reverse cholesterol transport was originally described as the high-density lipoprotein-mediated cholesterol flux from the periphery via the hepatobiliary tract to the intestinal lumen, leading to fecal excretion. Since the introduction of reverse cholesterol transport in the 1970s, this pathway has been intensively investigated. In this topic highlight, the classical reverse cholesterol transport concepts are discussed and the subject reverse cholesterol transport is revisited.

  11. Wheat alkylresorcinols reduce micellar solubility of cholesterol in vitro and increase cholesterol excretion in mice.

    Science.gov (United States)

    Horikawa, Kazumasa; Hashimoto, Chiaki; Kikuchi, Yosuke; Makita, Miki; Fukudome, Shin-Ichi; Okita, Kimiko; Wada, Naoyuki; Oishi, Katsutaka

    2017-03-01

    Epidemiological studies have shown that the consumption of whole grains can reduce risk for metabolic disorders. We recently showed that chronic supplementation with wheat alkylresorcinols (ARs) prevents glucose intolerance and insulin resistance with hepatic lipid accumulation induced in mice by a high-fat high-sucrose diet (HFHSD). This study examines the effects of ARs on the micellar solubility of cholesterol in vitro, as well as the effects of transient AR supplementation on faecal lipid excretion and plasma lipid levels in mice. We found that ARs formed bile micelles with taurocholate independently of phospholipids, and dose-dependently decreased the micellar solubility of cholesterol in a biliary micelle model. Transient AR supplementation with HFHSD increased faecal cholesterol and triglyceride contents and decreased plasma cholesterol concentrations. These suggest that one underlying mechanism through which ARs suppress diet-induced obesity is by interfering with the micellar cholesterol solubilisation in the digestive tract, which subsequently decreases cholesterol absorption.

  12. Macropinocytosis contributes to the macrophage foam cell formation in RAW264.7 cells

    Institute of Scientific and Technical Information of China (English)

    Wenqi Yao; Ke Li; Kan Liao

    2009-01-01

    The key event in the atherosclerosis development is the lipids uptake by macrophage and the formation of foam cell in subendothelial arterial space. Besides the uptake of modified low-density lipoprotein (LDL) by scavenger receptor-mediated endocytosis, macrophages possess constitutive macropinocytosis, which is capable of taking up a large quantity of solute. Macrophage foam cell formation could be induced in RAW264.7 cells by increasing the serum concentration in the culture medium. Foam cell formation induced by serum could be blocked by phosphoinositide 3-kinase inhibi-tor, LY294002 or wortmannin, which inhibited macro-pinocytosis but not receptor-mediated endocytosis. Further analysis indicated that macropinocytosis took place at the gangliosides-enriched membrane area. Cholesterol depletion by β-methylcyclodextrin-blocked macropinocytosis without affecting scavenger receptor-mediated endocytosis of modified LDLs. These results suggested that macropinocytosis might be one of the important mechanisms for lipid uptake in macrophage. And it made significant contribution to the lipid accumulation and foam cell formation.

  13. Tissue storage and control of cholesterol metabolism in man on high cholesterol diets.

    Science.gov (United States)

    Quintão, E C; Brumer, S; Stechhahn, K

    1977-03-01

    The possibility of accumulation of tissue cholesterol in human beings submitted to high cholesterol feeding was investigated in liver biopsies and through fecal sterol balance studies. Feeding to 10 individuals 3.1 to 3.4 g/day of cholesterol for 3 weeks raised the mean serum level from 293 to 349 mg/100 ml, namely 19%, whereas the liver cholesterol content was 417 mg/100 g of wet weight. In 10 control cases eating 0.1--0.4 g/day of cholesterol serum cholesterol remained stable throughout the experimental period and the liver cholesterol content was 256 mg/100 g. Difference of liver colesterol level between the two groups was 62%. In 7 patients submitted to two periods of balance investigation on a cholesterol-free synthetic formula diet respectively prior to (PI) and after (PIII) eating the high cholesterol solid food from 4 to 15 weeks (PII), fecal steroid excretion in PIII exceeded PI in 3 patients. Such data are a direct evidence for the existence of an efficient system to release acutely stored cholesterol. In one patient bile acid excretion accounted for the difference between PIII and PI.

  14. Chronic insulin therapy reduces adipose tissue macrophage content in LDL-receptor-deficient mice.

    Science.gov (United States)

    Yoon, J; Subramanian, S; Ding, Y; Wang, S; Goodspeed, L; Sullivan, B; Kim, J; O'Brien, K D; Chait, A

    2011-05-01

    Insulin has anti-inflammatory effects in short-term experiments. However, the effects of chronic insulin administration on inflammation are unknown. We hypothesised that chronic insulin administration would beneficially alter adipose tissue inflammation and several circulating inflammatory markers. We administered two forms of long-acting insulin, insulin glargine (A21Gly,B31Arg,B32Arg human insulin) and insulin detemir (B29Lys[ε-tetradecanoyl],desB30 human insulin), to LDL-receptor-deficient mice. After 8 weeks on a diet that causes obesity, hyperglycaemia, adipose tissue macrophage accumulation and atherosclerosis, the mice received subcutaneous glargine, detemir or NaCl (control) for 12 weeks. Serum amyloid A (SAA) and serum amyloid P (SAP), metabolic variables, adipose tissue macrophages and aortic atherosclerosis were evaluated. Weight gain was equivalent in all groups. The glycated haemoglobin level fell equivalently in both insulin-treated groups. Plasma cholesterol and triacylglycerol levels, and hepatic triacylglycerol level significantly improved in the glargine compared with the detemir or control groups. Levels of mRNA expression for monocyte chemotactic protein-1 and F4/80, a macrophage marker, in adipose tissue were decreased only in the glargine group (p adipose tissue macrophage content decreased in both insulin groups (p insulin-treated group, but IL-6 levels fell in the glargine-treated mice. While chronic insulin administration did not decrease SAA and SAP, administration of glargine but not detemir insulin improved dyslipidaemia, IL-6 levels and atherosclerosis, and both insulins reduced macrophage accumulation in visceral adipose tissue. Thus, chronic insulin therapy has beneficial tissue effects independent of circulating inflammatory markers in this murine model of diet-induced obesity and diabetes.

  15. Mitofusin 2 decreases intracellular lipids in macrophages by regulating peroxisome proliferator-activated receptor-γ

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Chun; Ge, Beihai [Department of Cardiology, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, 1095 Jiefang Avenue, Wuhan 430030 (China); He, Chao [Department of Cardiology, China Three Gorges University, Yichang 433000 (China); Zhang, Yi; Liu, Xiaowen [Department of Cardiology, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, 1095 Jiefang Avenue, Wuhan 430030 (China); Liu, Kejian [Department of Cardiology, The First Affiliated Hospital of Medical College, Shihezi University (China); Qian, Cuiping; Zhang, Yu; Peng, Wenzhong [Department of Cardiology, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, 1095 Jiefang Avenue, Wuhan 430030 (China); Guo, Xiaomei, E-mail: xmguo@tjh.tjmu.edu.cn [Department of Cardiology, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, 1095 Jiefang Avenue, Wuhan 430030 (China)

    2014-07-18

    Highlights: • Mfn2 decreases cellular lipid accumulation by activating cholesterol transporters. • PPARγ is involved in the Mfn2-mediated increase of cholesterol transporter expressions. • Inactivation of ERK1/2 and p38 is involved in Mfn2-induced PPARγ expression. - Abstract: Mitofusin 2 (Mfn2) inhibits atherosclerotic plaque formation, but the underlying mechanism remains elusive. This study aims to reveal how Mfn2 functions in the atherosclerosis. Mfn2 expression was found to be significantly reduced in arterial atherosclerotic lesions of both mice and human compared with healthy counterparts. Here, we observed that Mfn2 increased cellular cholesterol transporter expression in macrophages by upregulating peroxisome proliferator-activated receptor-γ, an effect achieved at least partially by inhibiting extracellular signal-regulated kinase1/2 (ERK1/2) and p38 mitogen-activated protein kinases (MAPKs) pathway. These findings provide insights into potential mechanisms of Mfn2-mediated alterations in cholesterol transporter expression, which may have significant implications for the treatment of atherosclerotic heart disease.

  16. Remnant cholesterol as a cause of ischemic heart disease

    DEFF Research Database (Denmark)

    Varbo, Anette; Benn, Marianne; Nordestgaard, Børge G

    2014-01-01

    This review focuses on remnant cholesterol as a causal risk factor for ischemic heart disease (IHD), on its definition, measurement, atherogenicity, and levels in high risk patient groups; in addition, present and future pharmacological approaches to lowering remnant cholesterol levels...... are considered. Observational studies show association between elevated levels of remnant cholesterol and increased risk of cardiovascular disease, even when remnant cholesterol levels are defined, measured, or calculated in different ways. In-vitro and animal studies also support the contention that elevated...... levels of remnant cholesterol may cause atherosclerosis same way as elevated levels of low-density lipoprotein (LDL) cholesterol, by cholesterol accumulation in the arterial wall. Genetic studies of variants associated with elevated remnant cholesterol levels show that an increment of 1mmol/L (39mg...

  17. Degradation of cholesterol crystals in phospholipids

    Science.gov (United States)

    Koren, Eugen; Koscec, Mirna; Fugate, Robert D.

    1993-02-01

    Based on previous studies from the laboratory that demonstrated degradation of cholesterol crystals ingested by macrophages in a cell culture system and indicated that intracellular phospholipids could play an important role in mobilization of crystalline cholesterol, the role of each of the three major intracellular phospholipid species in degradation of crystals is further explored. Fluorescently labeled cholesterol crystals are incubated with phospholipids over a period of 5 d. Morphological changes in crystals are monitored using digital imaging fluorescence microscopy, fluorescence redistribution after photobleaching, confocal microscopy, and epifluorescent and phase contrast microscopy. Results clearly demonstrate that all three phospholipids are able to mobilize crystalline cholesterol. However, the mechanisms by which they exert mobilization are different. Sphingomyelin and phosphatidylchloline are found to cause gradual and uniform dissolution of crystals, more or less preserving their original shape. Phosphatidylethanolamine appear to penetrate into the crystal, causing its fragmentation and solubilization. In the mixture of all three phospholipids representing the composition found in macrophages, both of the described mechanisms are working simultaneously.

  18. Cholesterol testing and results

    Science.gov (United States)

    Cholesterol test results; LDL test results; VLDL test results; HDL test results; Coronary risk profile results; Hyperlipidemia- ... Some cholesterol is considered good and some is considered bad. Different blood tests can be done to measure each ...

  19. Controlling Cholesterol with Statins

    Science.gov (United States)

    ... For Consumers Home For Consumers Consumer Updates Controlling Cholesterol with Statins Share Tweet Linkedin Pin it More ... not, the following tips can help keep your cholesterol in check: Talk with your healthcare provider about ...

  20. Cholesterol - drug treatment

    Science.gov (United States)

    ... this page: //medlineplus.gov/ency/patientinstructions/000314.htm Cholesterol - drug treatment To use the sharing features on ... treatment; Hardening of the arteries - statin Statins for Cholesterol Statins reduce your risk of heart disease, stroke, ...

  1. Cholesterol and public policy.

    Science.gov (United States)

    LaRosa, J C

    1994-08-01

    Cholesterol lowering in both primary and secondary prevention has been clearly demonstrated to lower coronary morbidity and, in secondary prevention, to lower coronary mortality as well. Putative dangers of cholesterol lowering remain unproven. Population studies linking low cholesterol to noncoronary mortalities do not demonstrate cause-and-effect relations. In fact, based on current studies, the opposite is more likely to be the case. Neither gender nor age should automatically exclude persons from cholesterol screening. Drug intervention, however, should be used conservatively, particularly in young adults and the elderly. Drugs should be used only after diet and lifestyle interventions have failed. The evidence linking high blood cholesterol to coronary atherosclerosis and cholesterol lowering to its prevention is broad-based and definitive. Concerns about cholesterol lowering and spontaneously low cholesterols should be pursued but should not interfere with the implementation of current public policies to reduce the still heavy burden of atherosclerosis in Western society.

  2. High blood cholesterol levels

    Science.gov (United States)

    ... this page: //medlineplus.gov/ency/article/000403.htm High blood cholesterol levels To use the sharing features ... stroke, and other problems. The medical term for high blood cholesterol is lipid disorder, hyperlipidemia, or hypercholesterolemia. ...

  3. Serum cholesterol acceptor capacity in intrauterine growth restricted fetuses.

    Science.gov (United States)

    Pecks, Ulrich; Rath, Werner; Bauerschlag, Dirk O; Maass, Nicolai; Orlikowsky, Thorsten; Mohaupt, Markus G; Escher, Geneviève

    2017-02-14

    Intrauterine growth restriction (IUGR) is an independent risk factor for the development of cardiovascular diseases later in life. The mechanisms whereby slowed intrauterine growth confers vascular risk are not clearly established. In general, a disturbed cholesterol efflux has been linked to atherosclerosis. The capacity of serum to accept cholesterol has been repeatedly evaluated in clinical studies by the use of macrophage-based cholesterol efflux assays and, if disturbed, precedes atherosclerotic diseases years before the clinical diagnosis. We now hypothesized that circulating cholesterol acceptors in IUGR sera specifically interfere with cholesterol transport mechanisms leading to diminished cholesterol efflux. RAW264.7 cells were used to determine efflux of [3H]-cholesterol in response to [umbilical cord serum (IUGR), n=20; controls (CTRL), n=20]. Cholesterol efflux was lower in IUGR as compared to controls [controls: mean 7.7% fractional [3H]-cholesterol efflux, standard deviation (SD)=0.98; IUGR: mean 6.3%, SD=0.79; P<0.0001]. Values strongly correlated to HDL (ρ=0.655, P<0.0001) and apoE (ρ=0.510, P=0.0008), and mildly to apoA1 (ρ=0.3926, P=0.0122) concentrations. Reduced cholesterol efflux in IUGR could account for the enhanced risk of developing cardiovascular diseases later in life.

  4. Cholesterol oxides inhibit cholesterol esterification by lecithin: cholesterol acyl transferase

    Directory of Open Access Journals (Sweden)

    Eder de Carvalho Pincinato

    2009-09-01

    Full Text Available Cholesterol oxides are atherogenic and can affect the activity of diverse important enzymes for the lipidic metabolism. The effect of 7β-hydroxycholesterol, 7-ketocholesterol, 25-hydroxycholesterol, cholestan-3β,5α,6β-triol,5,6β-epoxycholesterol, 5,6α-epoxycholesterol and 7α-hydroxycholesterol on esterification of cholesterol by lecithin:cholesterol acyl transferase (LCAT, EC 2.3.1.43 and the transfer of esters of cholesterol oxides from high density lipoprotein (HDL to low density lipoproteins (LDL and very low density lipoproteins (VLDL by cholesteryl ester transfer protein (CETP was investigated. HDL enriched with increasing concentrations of cholesterol oxides was incubated with fresh plasma as source of LCAT. Cholesterol and cholesterol oxides esterification was followed by measuring the consumption of respective free sterol and oxysterols. Measurements of cholesterol and cholesterol oxides were done by gas-chromatography. 14C-cholesterol oxides were incorporated into HDL2 and HDL3 subfractions and then incubated with fresh plasma containing LCAT and CETP. The transfer of cholesterol oxide esters was followed by measuring the 14C-cholesterol oxide-derived esters transferred to LDL and VLDL. All the cholesterol oxides studied were esterified by LCAT after incorporation into HDL particles, competing with cholesterol by LCAT. Cholesterol esterification by LCAT was inversely related to the cholesterol oxide concentration. The esterification of 14C-cholesterol oxides was higher in HDL3 and the transfer of the derived esters was greater from HDL2 to LDL and VLDL. The results suggest that cholesterol esterification by LCAT is inhibited in cholesterol oxide-enriched HDL particles. Moreover, the cholesterol oxides-derived esters are efficiently transferred to LDL and VLDL. Therefore, we suggest that cholesterol oxides may exert part of their atherogenic effect by inhibiting cholesterol esterification on the HDL surface and thereby disturbing

  5. What Your Cholesterol Levels Mean

    Science.gov (United States)

    ... Disease Venous Thromboembolism Aortic Aneurysm More What Your Cholesterol Levels Mean Updated:Apr 3,2017 Keeping your ... content was last reviewed on 04/21/2014. Cholesterol • Home • About Cholesterol Introduction Good vs. Bad Cholesterol ...

  6. Home-Use Tests - Cholesterol

    Science.gov (United States)

    ... Medical Procedures In Vitro Diagnostics Home Use Tests Cholesterol Share Tweet Linkedin Pin it More sharing options ... a home-use test kit to measure total cholesterol. What cholesterol is: Cholesterol is a fat (lipid) ...

  7. High fat/high cholesterol diet induced lipid accumulation in pulmonary tissues of C57BL/6J mice%高脂高胆固醇饮食致C57BL/6J小鼠肺组织脂质蓄积的研究

    Institute of Scientific and Technical Information of China (English)

    王双; 朱婷婷; 方严; 陈婷; 张恋; 练雪梅

    2012-01-01

    目的:研究高脂高胆固醇饮食(Paigen 饮食)是否可以导致C57BL/6J小鼠肺组织的脂质蓄积.方法:66只C57BL/6J雄性6~8周龄小鼠随机分为2组,分别喂饲普通饮食和Paigen饮食,于喂养12、16、20周3个时间点,取主动脉做冰冻切片,油红O染色观察粥样硬化斑块形成情况;肺组织冰冻切片油红O染色,观察肺组织脂质蓄积情况;体外培养A549细胞观察用不同浓度低密度脂蛋白(Low density lipoprotein,LDL)处理后,A549细胞内脂质蓄积情况.结果:Paigen饮食可导致C57BL/6J小鼠主动脉粥样硬化;同时,不同时间点C57BL/6J小鼠肺组织油红O染色结果提示该饮食还可以导致C57BL/6J小鼠肺组织出现脂质蓄积,并随着时间延长而加剧;不同浓度LDL刺激A549细胞的油红O染色结果提示:A549细胞的脂质蓄积与LDL处理的浓度间存在剂最效应关系.结论:Paigen 饮食可以导致C57BL/6J小鼠肺脏出现时间依赖性的脂质蓄积,其机制可能与肺泡Ⅱ型上皮细胞的脂质代谢异常有关.%Objective: To investigate whether high fat/high cholesterol diet(Paigen diet) could lead lipid accumulation in pulmonary tissues of C57BL/6J mice. Methods: Sixty six C57BL/6J male mice were randomly divided into two groups and were treated with regular diet and high fat/high cholesterol diet respectively. The pulmonary tissues were collected at the 12lh,16th week and the 20th week alter feeding respectively. The aortas atherosclerotic plaque and lipidosis in pulmonary tissues were determined by oil red 0 staining. A549 cells were cultured in vitro and were treated with different concentrations of low density lipoprotein(LDL) to observe the effect of cholesterol loading on alveolar lipid accumulation in vitro. Results: Aorta atherosclerosis plaques were observed in high fat/high cholesterol diet treated C57BI76J mice. Oil red 0 staining of pulmonary tissues at different time points suggested that high fat/ high cholesterol diet

  8. Limiting Cholesterol Biosynthetic Flux Spontaneously Engages Type I IFN Signaling.

    Science.gov (United States)

    York, Autumn G; Williams, Kevin J; Argus, Joseph P; Zhou, Quan D; Brar, Gurpreet; Vergnes, Laurent; Gray, Elizabeth E; Zhen, Anjie; Wu, Nicholas C; Yamada, Douglas H; Cunningham, Cameron R; Tarling, Elizabeth J; Wilks, Moses Q; Casero, David; Gray, David H; Yu, Amy K; Wang, Eric S; Brooks, David G; Sun, Ren; Kitchen, Scott G; Wu, Ting-Ting; Reue, Karen; Stetson, Daniel B; Bensinger, Steven J

    2015-12-17

    Cellular lipid requirements are achieved through a combination of biosynthesis and import programs. Using isotope tracer analysis, we show that type I interferon (IFN) signaling shifts the balance of these programs by decreasing synthesis and increasing import of cholesterol and long chain fatty acids. Genetically enforcing this metabolic shift in macrophages is sufficient to render mice resistant to viral challenge, demonstrating the importance of reprogramming the balance of these two metabolic pathways in vivo. Unexpectedly, mechanistic studies reveal that limiting flux through the cholesterol biosynthetic pathway spontaneously engages a type I IFN response in a STING-dependent manner. The upregulation of type I IFNs was traced to a decrease in the pool size of synthesized cholesterol and could be inhibited by replenishing cells with free cholesterol. Taken together, these studies delineate a metabolic-inflammatory circuit that links perturbations in cholesterol biosynthesis with activation of innate immunity.

  9. Mitochondrion-Targeted Peptide SS-31 Inhibited Oxidized Low-Density Lipoproteins-Induced Foam Cell Formation through both ROS Scavenging and Inhibition of Cholesterol Influx in RAW264.7 Cells.

    Science.gov (United States)

    Hao, Shuangying; Ji, Jiajie; Zhao, Hongting; Shang, Longcheng; Wu, Jing; Li, Huihui; Qiao, Tong; Li, Kuanyu

    2015-12-01

    Foam cell formation as a result of imbalance of modified cholesterol influx and efflux by macrophages is a key to the occurrence and development of atherosclerosis. Oxidative stress is thought to be involved in the pathogenesis of atherosclerosis. SS-31 is a member of the Szeto-Schiller (SS) peptides shown to specifically target the inner mitochondrial membrane to scavenge reactive oxygen species. In this study, we investigated whether SS-31 may provide protective effect on macrophage from foam cell formation in RAW264.7 cells. The results showed that SS-31 inhibited oxidized low-density lipoproteins (ox-LDL)-induced foam cell formation and cholesterol accumulation, demonstrated by intracellular oil red O staining and measurement of cholesterol content. The mechanism was revealed that SS-31 did not only significantly attenuated ox-LDL-induced generation of reactive oxygen species (ROS) and increased the activities of superoxide dismutases, but also dose-dependently inhibited the expression of CD36 and LOX-1, two scavenger receptors of ox-LDL, while the expression of ATP-binding cassette A1 and G1, playing a pivotal role in cholesterol efflux, was not affected. As a result, SS-31 decreased pro-inflammatory cytokines such as interleukin 6 and tumor necrosis factor alpha, suggesting the prevention of inflammatory responses. In conclusion, our results demonstrate that SS-31 provides a beneficial effect on macrophages from foam cell formation, likely, through both ROS scavenging and inhibition of cholesterol influx. Therefore, SS-31 may potentially be of therapeutic relevance in prevention of human atherogenesis.

  10. Effects of saturated and unsaturated fats given with and without dietary cholesterol on hepatic cholesterol synthesis and hepatic lipid metabolism.

    Science.gov (United States)

    Bochenek, W; Rodgers, J B

    1978-01-27

    Hepatic cholesterol synthesis was studied in rats after consuming diets of varying neutral lipid and cholesterol content. Cholesterol synthesis was evaluated by measuring 3-hydroxy-3-methylglutaryl-CoA reductase and by determining the rate of 3H-labeled sterol production from [3H]mevalonate. Results were correlated with sterol balance data and hepatic lipid content. Hepatic cholesterol synthesis was relatively great when cholesterol was excluded from the diet. The source of neutral dietary lipids, saturated vs. unsaturated, produced no change in hepatic sterol synthesis. Values for fecal sterol outputs and hepatic cholesterol levels were also similar in rats consuming either saturated or unsaturated fats. When 1% cholesterol was added to the diet, hepatic cholesterol synthesis was suppressed but the degree of suppression was greater in rats consuming unsaturated vs. saturated fats. This was associated with greater accumulation of cholesterol in livers from rats consuming unsaturates and a reduction in fecal neutral sterol output in this group as opposed to results from rats on saturated fats. Cholesterol consumption also altered the fatty acid composition of hepatic phospholipids producing decreases in the percentages of essential polyunsaturated fatty acids. It is concluded that dietary cholesterol alters cholesterol and fatty acid metabolism in the liver and that this effect is enhanced by dietary unsaturated fats.

  11. Lipid synthesis in macrophages during inflammation in vivo: effect of agonists of peroxisome proliferator activated receptors alpha and gamma and of retinoid X receptors.

    Science.gov (United States)

    Posokhova, E N; Khoshchenko, O M; Chasovskikh, M I; Pivovarova, E N; Dushkin, M I

    2008-03-01

    The effects of peroxisome proliferator activated receptors alpha and gamma (PPAR-alpha and PPAR-gamma) and retinoid X receptor (RXR) agonists upon synthesis and accumulation of lipids in murine C57Bl macrophages during inflammation induced by injection of zymosan and Escherichia coli lipopolysaccharide (LPS) have been studied. It is significant that intraperitoneal injection of zymosan (50 mg/kg) or LPS (0.1 mg/kg) in mice led to a dramatic increase of [14C]oleate incorporation into cholesteryl esters and triglycerides and [14C]acetate incorporation into cholesterol and fatty acids in peritoneal macrophages. Lipid synthesis reached its maximum rate 18-24 h after injection and was decreased 5-7 days later to control level after LPS injection or was still heightened after zymosan injection. In macrophages obtained in acute phase of inflammation (24 h), degradation of 125I-labeled native low density lipoprotein (NLDL) was 4-fold increased and degradation of 125I-labeled acetylated LDL (AcLDL) was 2-3-fold decreased. Addition of NLDL (50 microg/ml) or AcLDL (25 microg/ml) into the incubation medium of activated macrophages induced 9-14- and 1.25-fold increase of cholesteryl ester synthesis, respectively, compared with control. Addition of NLDL and AcLDL into the incubation medium completely inhibited cholesterol synthesis in control macrophages but had only slightly effect on cholesterol synthesis in activated macrophages. Injection of RXR, PPAR-alpha, or PPAR-gamma agonists--9-cis-retinoic acid (5 mg/kg), bezafibrate (10 mg/kg), or rosiglitazone (10 mg/kg), respectively--30 min before zymosan or LPS injection led to significant decrease of lipid synthesis. Ten hour preincubation of activated in vivo macrophages with the abovementioned agonists (5 microM) decreased cholesteryl ester synthesis induced by NLDL and AcLDL addition into the cell cultivation medium. The data suggest that RXR, PPAR-alpha, or PPAR-gamma agonists inhibited lipid synthesis and induction of

  12. Non-cholesterol sterols and cholesterol metabolism in sitosterolemia.

    Science.gov (United States)

    Othman, Rgia A; Myrie, Semone B; Jones, Peter J H

    2013-12-01

    Sitosterolemia (STSL) is a rare autosomal recessive disease, manifested by extremely elevated plant sterols (PS) in plasma and tissue, leading to xanthoma and premature atherosclerotic disease. Therapeutic approaches include limiting PS intake, interrupting enterohepatic circulation of bile acid using bile acid binding resins such as cholestyramine, and/or ileal bypass, and inhibiting intestinal sterol absorption by ezetimibe (EZE). The objective of this review is to evaluate sterol metabolism in STSL and the impact of the currently available treatments on sterol trafficking in this disease. The role of PS in initiation of xanthomas and premature atherosclerosis is also discussed. Blocking sterols absorption with EZE has revolutionized STSL patient treatment as it reduces circulating levels of non-cholesterol sterols in STSL. However, none of the available treatments including EZE have normalized plasma PS concentrations. Future studies are needed to: (i) explore where cholesterol and non-cholesterol sterols accumulate, (ii) assess to what extent these sterols in tissues can be mobilized after blocking their absorption, and (iii) define the factors governing sterol flux.

  13. Low cholesterol and violence.

    Science.gov (United States)

    Mufti, R M; Balon, R; Arfken, C L

    1998-02-01

    The association between violent behavior and low serum total cholesterol levels was examined in a psychiatric inpatient population with diverse diagnoses. The study used a case-control design to compare the cholesterol levels of patients in a long-term psychiatric hospital who had a history of seclusion or restraints (N = 20) and those who did not (N = 20). A low cholesterol level was defined as less than 180 mg/dL. A strong association was found between low cholesterol levels and violent behavior (odds ratio = 15.49), an association that was not due to age, race, sex, or diagnosis. The finding was consistent whether mean levels or dichotomized levels of cholesterol were examined. Physical health, cholesterol-lowering medication, current alcohol use, or unusual diets could not explain the results. However, the raw frequency of episodes of seclusion or restraint as an indicator of the frequency of violent behavior was not associated with cholesterol level. Dichotomizing cholesterol levels at 180 mg/dL yielded high sensitivity (90 percent) for predicting violent behavior but at the cost of low specificity (65 percent). The results support the hypothesis that an association exists between low cholesterol and violent behavior among psychiatric patients but argue against using cholesterol level as a screening tool for predicting violent behavior.

  14. Significance of the percentage of cholesterol efflux capacity and total cholesterol efflux capacity in patients with or without coronary artery disease.

    Science.gov (United States)

    Norimatsu, Kenji; Kuwano, Takashi; Miura, Shin-Ichiro; Shimizu, Tomohiko; Shiga, Yuhei; Suematsu, Yasunori; Miyase, Yuiko; Adachi, Sen; Nakamura, Ayumi; Imaizumi, Satoshi; Iwata, Atsushi; Nishikawa, Hiroaki; Uehara, Yoshinari; Saku, Keijiro

    2017-01-01

    We hypothesized that cholesterol efflux capacity is more useful than the lipid profile as a marker of the presence and the severity of coronary artery disease (CAD). Therefore, we investigated the associations between the presence and the severity of CAD and both the percentage of cholesterol efflux capacity and total cholesterol efflux capacity and the lipid profile including the high-density lipoprotein cholesterol (HDL-C) level in patients who underwent coronary computed tomography angiography (CTA). The subjects consisted of 204 patients who were clinically suspected to have CAD and underwent CTA. We isolated HDL from plasma by ultracentrifugation and measured the percentage of cholesterol efflux capacity using (3)H-cholesterol-labeled J774 macrophage cells and calculated total cholesterol efflux capacity as follows: the percentage of cholesterol efflux capacity/100× HDL-C levels. While the percentage of cholesterol efflux capacity was not associated with the presence or the severity of CAD, total cholesterol efflux capacity and HDL-C in patients with CAD were significantly lower than those in patients without CAD. In addition, total cholesterol efflux capacity and HDL-C, but not the percentage of cholesterol efflux capacity, significantly decreased as the number of coronary arteries with significant stenosis increased. Total cholesterol efflux capacity was positively correlated with HDL-C, whereas the percentage of cholesterol efflux capacity showed only weak association. In a logistic regression analysis, the presence of CAD was independently associated with total cholesterol efflux capacity, in addition to age and gender. Finally, a receiver-operating characteristic curve analysis indicated that the areas under the curves for total cholesterol efflux capacity and HDL-C were similar. In conclusion, the percentage of cholesterol efflux capacity using the fixed amount of isolated HDL was not associated with CAD. On the other hand, the calculated total

  15. Regulation of cholesterol homeostasis.

    Science.gov (United States)

    van der Wulp, Mariëtte Y M; Verkade, Henkjan J; Groen, Albert K

    2013-04-10

    Hypercholesterolemia is an important risk factor for cardiovascular disease. It is caused by a disturbed balance between cholesterol secretion into the blood versus uptake. The pathways involved are regulated via a complex interplay of enzymes, transport proteins, transcription factors and non-coding RNA's. The last two decades insight into underlying mechanisms has increased vastly but there are still a lot of unknowns, particularly regarding intracellular cholesterol transport. After decades of concentration on the liver, in recent years the intestine has come into focus as an important control point in cholesterol homeostasis. This review will discuss current knowledge of cholesterol physiology, with emphasis on cholesterol absorption, cholesterol synthesis and fecal excretion, and new (possible) therapeutic options for hypercholesterolemia.

  16. Myeloid-Specific Krüppel-Like Factor 2 Inactivation Increases Macrophage and Neutrophil Adhesion and Promotes Atherosclerosis

    Science.gov (United States)

    Lingrel, Jerry B; Pilcher-Roberts, Robyn; Basford, Joshua E.; Manoharan, Palanikumar; Neumann, Jon; Konaniah, Eddy S.; Srinivasan, Ramprasad; Bogdanov, Vladimir Y; Hui, David Y.

    2012-01-01

    Rationale and Objective Hemizygous deficiency of the transcription factor Krüppel-like factor 2 (KLF2) has been shown previously to augment atherosclerosis in hypercholesterolemic mice. However, the cell type responsible for the increased atherosclerosis due to KLF2 deficiency has not been identified. This study examined the consequence of myeloid cell-specific KLF2 inactivation in atherosclerosis. Methods and Results Cell-specific knockout mice were generated by Cre/loxP recombination. Macrophages isolated from myeloid-specific Klf2 knockout (myeKlf2-/-) mice were similar to myeKlf2+/+ macrophages in response to activation, polarization, and lipid accumulation. However, in comparison to myeKlf2+/+ macrophages, myeKlf2-/- macrophages adhered more robustly to endothelial cells. Neutrophils from myeKlf2-/- mice also adhered more robustly to endothelial cells, and less myeKlf2-/- neutrophils survived in culture over a 24 hr period in comparison with myeKlf2+/+ neutrophils. When myeKlf2-/- mice were mated to Ldlr-/- mice and then fed a high fat and high cholesterol diet, significant increase in atherosclerosis was observed in the myeKlf2-/-Ldlr-/- mice compared to myeKlf2+/+Ldlr-/- littermates. The increased atherosclerosis in myeKlf2-/-Ldlr-/- mice was associated with elevated presence of neutrophils and macrophages, with corresponding increase of myeloperoxidase as well as chlorinated- and nitrosylated-tyrosine epitopes in their lesion areas compared to myeKlf2+/+Ldlr-/- mice. Conclusions This study documents a role for myeloid KLF2 expression in modulating atherosclerosis. The increased neutrophil accumulation and atherosclerosis progression with myeloid-specific KLF2 deficiency also underscores the importance of neutrophils in promoting vascular oxidative stress and atherosclerosis. Collectively, these results suggest that elevating KLF2 expression may be a novel strategy for prevention and treatment of atherosclerosis. PMID:22474254

  17. Dietary cholesterol, heart disease risk and cognitive dissonance.

    Science.gov (United States)

    McNamara, Donald J

    2014-05-01

    In the 1960s, the thesis that dietary cholesterol contributes to blood cholesterol and heart disease risk was a rational conclusion based on the available science at that time. Fifty years later the research evidence no longer supports this hypothesis yet changing the dietary recommendation to limit dietary cholesterol has been a slow and at times contentious process. The preponderance of the clinical and epidemiological data accumulated since the original dietary cholesterol restrictions were formulated indicate that: (1) dietary cholesterol has a small effect on the plasma cholesterol levels with an increase in the cholesterol content of the LDL particle and an increase in HDL cholesterol, with little effect on the LDL:HDL ratio, a significant indicator of heart disease risk, and (2) the lack of a significant relationship between cholesterol intake and heart disease incidence reported from numerous epidemiological surveys. Over the last decade, many countries and health promotion groups have modified their dietary recommendations to reflect the current evidence and to address a now recognised negative consequence of ineffective dietary cholesterol restrictions (such as inadequate choline intake). In contrast, health promotion groups in some countries appear to suffer from cognitive dissonance and continue to promote an outdated and potentially hazardous dietary recommendation based on an invalidated hypothesis. This review evaluates the evidence for and against dietary cholesterol restrictions and the potential consequences of such restrictions.

  18. Cholesterol and Copper Affect Learning and Memory in the Rabbit

    Directory of Open Access Journals (Sweden)

    Bernard G. Schreurs

    2013-01-01

    Full Text Available A rabbit model of Alzheimer’s disease based on feeding a cholesterol diet for eight weeks shows sixteen hallmarks of the disease including beta amyloid accumulation and learning and memory changes. Although we have shown that feeding 2% cholesterol and adding copper to the drinking water can retard learning, other studies have shown that feeding dietary cholesterol before learning can improve acquisition and feeding cholesterol after learning can degrade long-term memory. We explore the development of this model, the issues surrounding the role of copper, and the particular contributions of the late D. Larry Sparks.

  19. Impaired macrophage autophagy increases the immune response in obese mice by promoting proinflammatory macrophage polarization.

    Science.gov (United States)

    Liu, Kun; Zhao, Enpeng; Ilyas, Ghulam; Lalazar, Gadi; Lin, Yu; Haseeb, Muhammad; Tanaka, Kathryn E; Czaja, Mark J

    2015-01-01

    Recent evidence that excessive lipid accumulation can decrease cellular levels of autophagy and that autophagy regulates immune responsiveness suggested that impaired macrophage autophagy may promote the increased innate immune activation that underlies obesity. Primary bone marrow-derived macrophages (BMDM) and peritoneal macrophages from high-fat diet (HFD)-fed mice had decreased levels of autophagic flux indicating a generalized impairment of macrophage autophagy in obese mice. To assess the effects of decreased macrophage autophagy on inflammation, mice with a Lyz2-Cre-mediated knockout of Atg5 in macrophages were fed a HFD and treated with low-dose lipopolysaccharide (LPS). Knockout mice developed systemic and hepatic inflammation with HFD feeding and LPS. This effect was liver specific as knockout mice did not have increased adipose tissue inflammation. The mechanism by which the loss of autophagy promoted inflammation was through the regulation of macrophage polarization. BMDM and Kupffer cells from knockout mice exhibited abnormalities in polarization with both increased proinflammatory M1 and decreased anti-inflammatory M2 polarization as determined by measures of genes and proteins. The heightened hepatic inflammatory response in HFD-fed, LPS-treated knockout mice led to liver injury without affecting steatosis. These findings demonstrate that autophagy has a critical regulatory function in macrophage polarization that downregulates inflammation. Defects in macrophage autophagy may underlie inflammatory disease states such as the decrease in macrophage autophagy with obesity that leads to hepatic inflammation and the progression to liver injury.

  20. Cholesterol - what to ask your doctor

    Science.gov (United States)

    ... your doctor; What to ask your doctor about cholesterol ... What is my cholesterol level? What should my cholesterol level be? What are HDL ("good") cholesterol and LDL ("bad") cholesterol? Does my cholesterol ...

  1. Regulation of cerebral cholesterol metabolism in Alzheimer disease.

    Science.gov (United States)

    Reiss, Allison B; Voloshyna, Iryna

    2012-03-01

    Alzheimer disease (AD) is an age-related neurodegenerative disorder that manifests as a progressive loss of memory and deterioration of higher cognitive functions. Alzheimer disease is characterized by accumulation in the brain of the β-amyloid peptide generated by β- and γ-secretase processing of amyloid precursor protein. Epidemiological studies have linked elevated plasma cholesterol and lipoprotein levels in midlife with AD development. Cholesterol-fed animal models exhibit neuropathologic features of AD including accumulation of β-amyloid peptide. Specific isoforms of the cholesterol transporter apolipoprotein E are associated with susceptibility to AD. Although multiple lines of evidence indicate a role for cholesterol in AD, the exact impact and mechanisms involved remain largely unknown. This review summarizes the current state of our knowledge of the influence of cholesterol and lipid pathways in AD pathogenesis in vitro and in vivo.

  2. National Cholesterol Education Month

    Centers for Disease Control (CDC) Podcasts

    2009-09-01

    Do you know your cholesterol numbers? Your doctor can do a simple test to check your cholesterol levels and help you make choices that lower your risk for heart disease and stroke.  Created: 9/1/2009 by National Center for Chronic Disease Prevention and Health Promotion (NCCDPHP).   Date Released: 9/9/2009.

  3. 胆固醇逆转运的新途径:胆固醇经肠道直接排出体外?%Novel Pathway for Reverse Cholesterol Transport: Directly Transintestinal Cholesterol Efflux?

    Institute of Scientific and Technical Information of China (English)

    司艳红; 商战平; 秦树存

    2011-01-01

    过多的胆固醇沉积在动脉壁对机体极为有害,可以引起动脉粥样硬化甚至心血管疾病.而胆固醇逆转运(reverse cholesterol transport,RCT)可以逆转此过程.传统的RCT是指胆固醇由外周组织转运回肝脏进行再循环或以胆汁酸的形式随粪便排出体外的过程,此过程受多种因子调控.近几年研究发现,胆固醇还可由血经过肠道直接分泌(transintestinal cholesterol efflux,TICE)通路随粪便排出体外,此过程对外界刺激更敏感.RCT已经成为防治动脉粥样硬化研究的新靶点,TICE有可能成为更有效的RCT调控通路.%The presence of excess cholesterol in cells, and in particular in macrophages in the arterial vessel wall, might be harmful. The accumulation of cholesterol in arteries can lead to atherosclerosis, and in turn, to other cardiovascular diseases. Reverse cholesterol transport ( RCT) can reverse this processing. By the pathway of classic RCT, excess cholesterol is collected from peripheral tissues and delivered back to the liver and hepatobiliary tract for excretion via the feces. This processing could be affected by many factors. For a long time this removal via the hepatobiliary secretion was considered to be the sole route involved in the RCT. In the last few years it has become evident that a nonbiliary cholesterol secretion pathway exists. That is the transintestinal cholesterol efflux ( TICE) pathway. Moreover, recent studies have shown that TICE is also sensitive to stimulation. Therefore, RCT, especially TICE, was seen as a suitable and approachable target for the development of drugs aimed at the prevention of atherosclerosis.

  4. Lentivirus-ABCG1 instillation reduces lipid accumulation and improves lung compliance in GM-CSF knock-out mice

    Energy Technology Data Exchange (ETDEWEB)

    Malur, Anagha; Huizar, Isham [Program in Lung Cell Biology and Translational Research, Division of Pulmonary, Critical Care and Sleep Medicine, East Carolina University, Greenville, NC (United States); Wells, Greg [Department of Microbiology and Immunology, East Carolina University, Greenville, NC (United States); Barna, Barbara P. [Program in Lung Cell Biology and Translational Research, Division of Pulmonary, Critical Care and Sleep Medicine, East Carolina University, Greenville, NC (United States); Malur, Achut G. [Department of Microbiology and Immunology, East Carolina University, Greenville, NC (United States); Thomassen, Mary Jane, E-mail: thomassenm@ecu.edu [Program in Lung Cell Biology and Translational Research, Division of Pulmonary, Critical Care and Sleep Medicine, East Carolina University, Greenville, NC (United States); Department of Microbiology and Immunology, East Carolina University, Greenville, NC (United States)

    2011-11-18

    Highlights: Black-Right-Pointing-Pointer Lentivirus-ABCG1 reduces lipid accumulation in lungs of GM-CSF knock-out mice. Black-Right-Pointing-Pointer Up-regulation of ABCG1 improves lung function. Black-Right-Pointing-Pointer Upregulation of ABCG1 improves surfactant metabolism. -- Abstract: We have shown decreased expression of the nuclear transcription factor, peroxisome proliferator-activated receptor-gamma (PPAR{gamma}) and the PPAR{gamma}-regulated ATP-binding cassette transporter G1 (ABCG1) in alveolar macrophages from patients with pulmonary alveolar proteinosis (PAP). PAP patients also exhibit neutralizing antibodies to granulocyte-macrophage colony stimulating factor (GM-CSF), an upregulator of PPAR{gamma}. In association with functional GM-CSF deficiency, PAP lung is characterized by surfactant-filled alveolar spaces and lipid-filled alveolar macrophages. Similar pathology characterizes GM-CSF knock-out (KO) mice. We reported previously that intratracheal instillation of a lentivirus (lenti)-PPAR{gamma} plasmid into GM-CSF KO animals elevated ABCG1 and reduced alveolar macrophage lipid accumulation. Here, we hypothesized that instillation of lenti-ABCG1 might be sufficient to decrease lipid accumulation and improve pulmonary function in GM-CSF KO mice. Animals received intratracheal instillation of lenti-ABCG1 or control lenti-enhanced Green Fluorescent Protein (eGFP) plasmids and alveolar macrophages were harvested 10 days later. Alveolar macrophage transduction efficiency was 79% as shown by lenti-eGFP fluorescence. Quantitative PCR analyses indicated a threefold (p = 0.0005) increase in ABCG1 expression with no change of PPAR{gamma} or ABCA1 in alveolar macrophages of lenti-ABCG1 treated mice. ABCG1 was unchanged in control lenti-eGFP and PBS-instilled groups. Oil Red O staining detected reduced intracellular neutral lipid in alveolar macrophages from lenti-ABCG1 treated mice. Extracellular cholesterol and phospholipids were also decreased as shown by

  5. Mitochondrial cholesterol: mechanisms of import and effects on mitochondrial function.

    Science.gov (United States)

    Martin, Laura A; Kennedy, Barry E; Karten, Barbara

    2016-04-01

    Mitochondria require cholesterol for biogenesis and membrane maintenance, and for the synthesis of steroids, oxysterols and hepatic bile acids. Multiple pathways mediate the transport of cholesterol from different subcellular pools to mitochondria. In steroidogenic cells, the steroidogenic acute regulatory protein (StAR) interacts with a mitochondrial protein complex to mediate cholesterol delivery to the inner mitochondrial membrane for conversion to pregnenolone. In non-steroidogenic cells, several members of a protein family defined by the presence of a StAR-related lipid transfer (START) domain play key roles in the delivery of cholesterol to mitochondrial membranes. Subdomains of the endoplasmic reticulum (ER), termed mitochondria-associated ER membranes (MAM), form membrane contact sites with mitochondria and may contribute to the transport of ER cholesterol to mitochondria, either independently or in conjunction with lipid-transfer proteins. Model systems of mitochondria enriched with cholesterol in vitro and mitochondria isolated from cells with (patho)physiological mitochondrial cholesterol accumulation clearly demonstrate that mitochondrial cholesterol levels affect mitochondrial function. Increased mitochondrial cholesterol levels have been observed in several diseases, including cancer, ischemia, steatohepatitis and neurodegenerative diseases, and influence disease pathology. Hence, a deeper understanding of the mechanisms maintaining mitochondrial cholesterol homeostasis may reveal additional targets for therapeutic intervention. Here we give a brief overview of mitochondrial cholesterol import in steroidogenic cells, and then focus on cholesterol trafficking pathways that deliver cholesterol to mitochondrial membranes in non-steroidogenic cells. We also briefly discuss the consequences of increased mitochondrial cholesterol levels on mitochondrial function and their potential role in disease pathology.

  6. Dissecting the membrane cholesterol requirement for mycobacterial entry into host cells.

    Science.gov (United States)

    Viswanathan, Gopinath; Jafurulla, Md; Kumar, G Aditya; Raghunand, Tirumalai R; Chattopadhyay, Amitabha

    2015-07-01

    Mycobacteria are intracellular pathogens that can invade and survive within host macrophages, and are a major cause of mortality and morbidity worldwide. The molecular mechanism involved in the internalization of mycobacteria is poorly understood. In this work, we have explored the role of host membrane cholesterol in the entry of the avirulent surrogate mycobacterial strain Mycobacterium smegmatis into THP-1 macrophages. Our results show that depletion of host membrane cholesterol using methyl-β-cyclodextrin results in a significant reduction in the entry of M. smegmatis into host cells. More importantly, we show that the inhibition in the ability of M. smegmatis to enter host macrophages could be reversed upon replenishment of membrane cholesterol. To the best of our knowledge, these results constitute the first report showing that membrane cholesterol replenishment can reverse the inhibition in the entry of mycobacteria into host cells. In addition, we demonstrate that cholesterol complexation using amphotericin B (without physical depletion) is sufficient to inhibit mycobacterial entry. Importantly, we observed a significant reduction in mycobacterial entry upon enrichment of host membrane cholesterol. Taken together, our results demonstrate, for the first time, that an optimum host plasma membrane cholesterol is necessary for the entry of mycobacteria. These results assume relevance in the context of developing novel therapeutic strategies targeting cholesterol-mediated mycobacterial host cell entry.

  7. What Causes High Blood Cholesterol?

    Science.gov (United States)

    ... the NHLBI on Twitter. What Causes High Blood Cholesterol? Many factors can affect the cholesterol levels in your blood. You can control some ... but not others. Factors You Can Control Diet Cholesterol is found in foods that come from animal ...

  8. Bile acid sequestrants for cholesterol

    Science.gov (United States)

    ... ency/patientinstructions/000787.htm Bile acid sequestrants for cholesterol To use the sharing features on this page, ... are medicines that help lower your LDL (bad) cholesterol . Too much cholesterol in your blood can stick ...

  9. HDL Cholesterol Efflux Capacity: Cardiovascular Risk Factor and Potential Therapeutic Target.

    Science.gov (United States)

    Bhatt, Anish; Rohatgi, Anand

    2016-01-01

    Low high-density lipoprotein cholesterol (HDL-C) levels are associated with incident cardiovascular events; however, many therapies targeting increases in HDL-C have failed to show consistent clinical benefit. Thus, focus has recently shifted toward measuring high-density lipoprotein (HDL) function. HDL is the key mediator of reverse cholesterol transport, the process of cholesterol extraction from foam cells, and eventual excretion into the biliary system. Cholesterol efflux from peripheral macrophages to HDL particles has been associated with atherosclerosis in both animals and humans. We review the mechanism of cholesterol efflux and the emerging evidence on the association between cholesterol efflux capacity and cardiovascular disease in human studies. We also focus on the completed and ongoing trials of novel therapies targeting different aspects of HDL cholesterol efflux.

  10. Early extracellular and cellular lipid deposits in aorta of cholesterol-fed rabbits.

    OpenAIRE

    Guyton, J. R.; Klemp, K. F.

    1992-01-01

    Subendothelial accumulation of extracellular liposomes rich in unesterified cholesterol has been described as an early feature of atherosclerosis induced by cholesterol feeding in rabbits. Beta-very-low-density lipoproteins, however, the presumed source of atherogenic lipid in this animal model, contain mostly esterified cholesterol. The purpose of this study was to test for the presence of extracellular neutral lipid deposits consistent with esterified cholesterol, by employing new electron ...

  11. Early extracellular and cellular lipid deposits in aorta of cholesterol-fed rabbits.

    OpenAIRE

    Guyton, J. R.; Klemp, K. F.

    1992-01-01

    Subendothelial accumulation of extracellular liposomes rich in unesterified cholesterol has been described as an early feature of atherosclerosis induced by cholesterol feeding in rabbits. Beta-very-low-density lipoproteins, however, the presumed source of atherogenic lipid in this animal model, contain mostly esterified cholesterol. The purpose of this study was to test for the presence of extracellular neutral lipid deposits consistent with esterified cholesterol, by employing new electron ...

  12. Macrophage Polarization in Obesity and Type 2 Diabetes: Weighing Down our Understanding of Macrophage Function?

    Directory of Open Access Journals (Sweden)

    Michael James Kraakman

    2014-09-01

    Full Text Available Obesity and type 2 diabetes are now recognized as chronic pro-inflammatory diseases. In the last decade, the role of the macrophage in particular has become increasingly implicated in their pathogenesis. Abundant literature now establishes that monocytes get recruited to peripheral tissues (ie pancreas, liver and adipose tissue to become resident macrophages and contribute to local inflammation, development of insulin resistance or even pancreatic dysfunction. Furthermore, an accumulation of evidence has established an important role for macrophage polarisation in the development of metabolic diseases. The general view in obesity is that there is an imbalance in the ratio of M1/M2 macrophages, with M1 pro-inflammatory macrophages being enhanced compared with M2 anti-inflammatory macrophages being down-regulated, leading to chronic inflammation and the propagation of metabolic dysfunction. However, there is emerging evidence revealing a more complex scenario with the spectrum of macrophage states exceeding well beyond the M1/M2 binary classification and confused further by human and animal models exhibiting different macrophage profiles. In this review we will discuss the recent findings regarding macrophage polarization in obesity and type 2 diabetes.

  13. Cholesterol and ocular pathologies: focus on the role of cholesterol-24S-hydroxylase in cholesterol homeostasis

    Directory of Open Access Journals (Sweden)

    Fourgeux Cynthia

    2015-03-01

    Full Text Available The retina is responsible for coding the light stimulus into a nervous signal that is transferred to the brain via the optic nerve. The retina is formed by the association of the neurosensory retina and the retinal pigment epithelium that is supported by Bruch’s membrane. Both the physical and metabolic associations between these partners are crucial for the functioning of the retina, by means of nutrient intake and removal of the cell and metabolic debris from the retina. Dysequilibrium are involved in the aging processes and pathologies such as age-related macular degeneration, the leading cause of visual loss after the age of 50 years in Western countries. The retina is composed of several populations of cells including glia that is involved in cholesterol biosynthesis. Cholesterol is the main sterol in the retina. It is present as free form in cells and as esters in Bruch’s membrane. Accumulation of cholesteryl esters has been associated with aging of the retina and impairment of the retinal function. Under dietary influence and in situ synthesized, the metabolism of cholesterol is regulated by cell interactions, including neurons and glia via cholesterol-24S-hydroxylase. Several pathophysiological associations with cholesterol and its metabolism can be suggested, especially in relation to glaucoma and age-related macular degeneration.

  14. Absence of Nceh1 augments 25-hydroxycholesterol-induced ER stress and apoptosis in macrophages[S

    Science.gov (United States)

    Sekiya, Motohiro; Yamamuro, Daisuke; Ohshiro, Taichi; Honda, Akira; Takahashi, Manabu; Kumagai, Masayoshi; Sakai, Kent; Nagashima, Shuichi; Tomoda, Hiroshi; Igarashi, Masaki; Okazaki, Hiroaki; Yagyu, Hiroaki; Osuga, Jun-ichi; Ishibashi, Shun

    2014-01-01

    An excess of cholesterol and/or oxysterols induces apoptosis in macrophages, contributing to the development of advanced atherosclerotic lesions. In foam cells, these sterols are stored in esterified forms, which are hydrolyzed by two enzymes: neutral cholesterol ester hydrolase 1 (Nceh1) and hormone-sensitive lipase (Lipe). A deficiency in either enzyme leads to accelerated growth of atherosclerotic lesions in mice. However, it is poorly understood how the esterification and hydrolysis of sterols are linked to apoptosis. Remarkably, Nceh1-deficient thioglycollate-elicited peritoneal macrophages (TGEMs), but not Lipe-deficient TGEMs, were more susceptible to apoptosis induced by oxysterols, particularly 25-hydroxycholesterol (25-HC), and incubation with 25-HC caused massive accumulation of 25-HC ester in the endoplasmic reticulum (ER) due to its defective hydrolysis, thereby activating ER stress signaling such as induction of CCAAT/enhancer-binding protein-homologous protein (CHOP). These changes were nearly reversed by inhibition of ACAT1. In conclusion, deficiency of Nceh1 augments 25-HC-induced ER stress and subsequent apoptosis in TGEMs. In addition to reducing the cholesteryl ester content of foam cells, Nceh1 may protect against the pro-apoptotic effect of oxysterols and modulate the development of atherosclerosis. PMID:24891333

  15. Cholesterol Balance in Prion Diseases and Alzheimer’s Disease

    Science.gov (United States)

    Hannaoui, Samia; Shim, Su Yeon; Cheng, Yo Ching; Corda, Erica; Gilch, Sabine

    2014-01-01

    Prion diseases are transmissible and fatal neurodegenerative disorders of humans and animals. They are characterized by the accumulation of PrPSc, an aberrantly folded isoform of the cellular prion protein PrPC, in the brains of affected individuals. PrPC is a cell surface glycoprotein attached to the outer leaflet of the plasma membrane by a glycosyl-phosphatidyl-inositol (GPI) anchor. Specifically, it is associated with lipid rafts, membrane microdomains enriched in cholesterol and sphinoglipids. It has been established that inhibition of endogenous cholesterol synthesis disturbs lipid raft association of PrPC and prevents PrPSc accumulation in neuronal cells. Additionally, prion conversion is reduced upon interference with cellular cholesterol uptake, endosomal export, or complexation at the plasma membrane. Altogether, these results demonstrate on the one hand the importance of cholesterol for prion propagation. On the other hand, growing evidence suggests that prion infection modulates neuronal cholesterol metabolism. Similar results were reported in Alzheimer’s disease (AD): whereas amyloid β peptide formation is influenced by cellular cholesterol, levels of cholesterol in the brains of affected individuals increase during the clinical course of the disease. In this review, we summarize commonalities of alterations in cholesterol homeostasis and discuss consequences for neuronal function and therapy of prion diseases and AD. PMID:25419621

  16. Regulation of cholesterol homeostasis

    NARCIS (Netherlands)

    van der Wulp, Mariette Y. M.; Verkade, Henkjan J.; Groen, Albert K.

    2013-01-01

    Hypercholesterolemia is an important risk factor for cardiovascular disease. It is caused by a disturbed balance between cholesterol secretion into the blood versus uptake. The pathways involved are regulated via a complex interplay of enzymes, transport proteins, transcription factors and

  17. Cholesterol and Women's Health

    Science.gov (United States)

    ... can I make to reduce my risk of cardiovascular disease? • Is there medication that can help reduce my cholesterol ... It also helps your body make vitamin D and produces the bile that helps you ...

  18. Oxidized LDL upregulated ATP binding cassette transporter-1 in THP-1 macrophages

    Institute of Scientific and Technical Information of China (English)

    Chao-ke TANG; Guang-hui YI; Jun-hao YANG; Lu-shan LIU; Zuo WANG; Chang-geng RUAN; Yong-zong YANG

    2004-01-01

    AIM: To study the effect of oxidized low density lipoprotein (ox-LDL) on ATP binding cassette transporter A1 (ABCA1) in THP-1 macrophages. METHODS: After exposing the cultured THP-1 macrophages to ox-LDL for different periods, cholesterol efflux was determined by FJ-2107P type liquid scintillator. ABCA1 mRNA and protein level were determined by reverse trancriptase-polymerase chain reaction (RT-PCR) and Western blot, respectively.The cholesterol level in THP-1 macrophage foam cells was detected by high performance liquid chromatography.RESULTS: ox-LDL elevated AB CA1 in both protein and mRNA levels and increased apolipoprotein (apo) A-I-mediated cholesterol efflux in a time- and dose-dependent manner. 22(R)-hydroxyeholesterol and 9-cis-retinoic acid did significantly increase cholesterol efflux in THP-1 macrophage foam cells (P<0.05), respectively. Both of them further promoted cholesterol efflux (P<0.01). As expected, liver X receptor (LXR) agonist decreased content of esterified cholesterol in the macrophage foam cells compared with control, whereas only a slight decrease of free cholesterol was observed. LXR activity was slightly increased by oxidized LDL by 12 % at 12 h compared with 6 h.However, LXR activity was increased about 1.8 times at 24 h, and oxidized LDL further increased LXR activity by about 2.6 times at 48 h. CONCLUSION: ABCA1 gene expression was markedly increased in cholesterol-loaded cells as a result of activation of LXR/RXR. ABCA1 plays an important role in the homeostasis of cholesterol in the macrophages.

  19. Role of Hepatic Lipase and Endothelial Lipase in High-Density Lipoprotein-Mediated Reverse Cholesterol Transport

    NARCIS (Netherlands)

    Annema, Wijtske; Tietge, Uwe J. F.

    2011-01-01

    Reverse cholesterol transport (RCT) constitutes a key part of the atheroprotective properties of high-density lipoproteins (HDL). Hepatic lipase (HL) and endothelial lipase (EL) are negative regulators of plasma HDL cholesterol levels. Although overexpression of EL decreases overall macrophage-to-fe

  20. Cholesterol in unusual places

    Energy Technology Data Exchange (ETDEWEB)

    Kucerka, N; Nieh, M P; Marquardt, D; Harroun, T A; Wassail, S R; Katsaras, J, E-mail: John.Katsaras@nrc.gc.ca, E-mail: Norbert.Kucerka@nrc.gc.ca

    2010-11-01

    Cholesterol is an essential component of mammalian cells, and is required for building and maintaining cell membranes, regulating their fluidity, and possibly acting as an antioxidant. Cholesterol has also been implicated in cell signaling processes, where it has been suggested that it triggers the formation of lipid rafts in the plasma membrane. Aside from cholesterol's physiological roles, what is also becoming clear is its poor affinity for lipids with unsaturated fatty acids as opposed to saturated lipids, such as sphingomyelin with which it forms rafts. We previously reported the location of cholesterol in membranes with varying degrees of acyl chain unsaturation as determined by neutron diffraction studies (Harroun et al 2006 Biochemistry 45, 1227; Harroun et al 2008 Biochemistry 47, 7090). In bilayers composed of phosphatidylcholine (PC) molecules with a saturated acyl chain at the sn-1 position or a monounsaturated acyl chain at both sn-1 and sn-2 positions, cholesterol was found in its much-accepted 'upright' position. However, in dipolyunsaturated 1,2-diarachidonyl phosphatidylcholine (20:4-20:4PC) membranes the molecule was found sequestered in the center of the bilayers. In further experiments, mixing l-palmitoyl-2-oleoyl phosphatidylcholine (16:0-18:1 PC) with 20:4-20:4PC resulted in cholesterol reverting to its upright orientation at approximately 40 mol% 16:0-18:1 PC. Interestingly, the same effect was achieved with only 5 mol% 1,2-dimyristoyl phosphatidylchoile (14:0-14:0PC).

  1. Characterization of early transient accumulation of PrP(Sc) in immune cells.

    Science.gov (United States)

    Elhelaly, Abdelazim Elsayed; Inoshima, Yasuo; Ishiguro, Naotaka

    2013-09-27

    PrP(Sc) is known to elicit no specific immune response and the immune cells are suspected to support its accumulation. In the present study, we investigated the response of some immune cell types to PrP(Sc) to characterize an observed early transient accumulation of PrP(Sc). After cells were treated with PrP(Sc)-brain homogenate, PrP(Sc) was transiently accumulated for the first 8-12h post-exposure then completely cleared by the 5th day of the experiment. The accumulated PrP(Sc) was not a de novo product of the cell PrP(C). Further investigation of this phenomenon revealed some potential factors influencing it. These factors included cholesterol homeostasis, temperature, the degradation power of the cell and the availability of sufficient PrP(C). Our in vitro results suggest that immune cells, especially macrophages are potential risk factors for the accumulation and intercellular spread of PrP(Sc) if the complete clearance of PrP(Sc) were not fulfilled.

  2. Empagliflozin, via Switching Metabolism Toward Lipid Utilization, Moderately Increases LDL Cholesterol Levels Through Reduced LDL Catabolism.

    Science.gov (United States)

    Briand, François; Mayoux, Eric; Brousseau, Emmanuel; Burr, Noémie; Urbain, Isabelle; Costard, Clément; Mark, Michael; Sulpice, Thierry

    2016-07-01

    In clinical trials, a small increase in LDL cholesterol has been reported with sodium-glucose cotransporter 2 (SGLT2) inhibitors. The mechanisms by which the SGLT2 inhibitor empagliflozin increases LDL cholesterol levels were investigated in hamsters with diet-induced dyslipidemia. Compared with vehicle, empagliflozin 30 mg/kg/day for 2 weeks significantly reduced fasting blood glucose by 18%, with significant increase in fasting plasma LDL cholesterol, free fatty acids, and total ketone bodies by 25, 49, and 116%, respectively. In fasting conditions, glycogen hepatic levels were further reduced by 84% with empagliflozin, while 3-hydroxy-3-methylglutaryl-CoA reductase activity and total cholesterol hepatic levels were 31 and 10% higher, respectively (both P catabolism of (3)H-cholesteryl oleate-labeled LDL injected intravenously by 20%, indicating that empagliflozin raises LDL levels through reduced catabolism. Unexpectedly, empagliflozin also reduced intestinal cholesterol absorption in vivo, which led to a significant increase in LDL- and macrophage-derived cholesterol fecal excretion (both P < 0.05 vs. vehicle). These data suggest that empagliflozin, by switching energy metabolism from carbohydrate to lipid utilization, moderately increases ketone production and LDL cholesterol levels. Interestingly, empagliflozin also reduces intestinal cholesterol absorption, which in turn promotes LDL- and macrophage-derived cholesterol fecal excretion.

  3. SIV Encephalitis Lesions Are Composed of CD163+ Macrophages Present in the Central Nervous System during Early SIV Infection and SIV-Positive Macrophages Recruited Terminally with AIDS

    Science.gov (United States)

    Nowlin, Brian T.; Burdo, Tricia H.; Midkiff, Cecily C.; Salemi, Marco; Alvarez, Xavier; Williams, Kenneth C.

    2016-01-01

    Macrophage recruitment to the central nervous system (CNS) during AIDS pathogenesis is poorly understood. We measured the accumulation of brain perivascular (CD163+) and inflammatory (MAC387+) macrophages in SIV-infected monkeys. Monocyte progenitors were 5-bromo-2′-deoxyuridine (BrdU) labeled in bone marrow, and CNS macrophages were labeled serially with fluorescent dextrans injected into the cisterna magna. MAC387+ macrophages accumulated in the meninges and choroid plexus in early inflammation and in the perivascular space and SIV encephalitis (SIVE) lesions late. CD163+ macrophages accumulated in the perivascular space and SIVE lesions with late inflammation. Most of the BrdU+ cells were MAC387+; however, CD163+BrdU+ macrophages were present in the meninges and choroid plexus with AIDS. Most (81.6% ± 1.8%) of macrophages in SIVE lesions were present in the CNS before SIVE lesion formation. There was a 2.9-fold increase in SIVp28+ macrophages entering the CNS late compared with those entering early (P CD163+ macrophage recruitment to the CNS inversely correlated with time to death (P CD163 correlated with CD163+ macrophage recruitment (P = 0.02). Most perivascular macrophages that comprise SIVE lesions and multinucleated giant cells are present in the CNS early, before SIVE lesions are formed. Most SIV-infected macrophages traffic to the CNS terminally with AIDS. PMID:25963554

  4. SIV encephalitis lesions are composed of CD163(+) macrophages present in the central nervous system during early SIV infection and SIV-positive macrophages recruited terminally with AIDS.

    Science.gov (United States)

    Nowlin, Brian T; Burdo, Tricia H; Midkiff, Cecily C; Salemi, Marco; Alvarez, Xavier; Williams, Kenneth C

    2015-06-01

    Macrophage recruitment to the central nervous system (CNS) during AIDS pathogenesis is poorly understood. We measured the accumulation of brain perivascular (CD163(+)) and inflammatory (MAC387(+)) macrophages in SIV-infected monkeys. Monocyte progenitors were 5-bromo-2'-deoxyuridine (BrdU) labeled in bone marrow, and CNS macrophages were labeled serially with fluorescent dextrans injected into the cisterna magna. MAC387(+) macrophages accumulated in the meninges and choroid plexus in early inflammation and in the perivascular space and SIV encephalitis (SIVE) lesions late. CD163(+) macrophages accumulated in the perivascular space and SIVE lesions with late inflammation. Most of the BrdU(+) cells were MAC387(+); however, CD163(+)BrdU(+) macrophages were present in the meninges and choroid plexus with AIDS. Most (81.6% ± 1.8%) of macrophages in SIVE lesions were present in the CNS before SIVE lesion formation. There was a 2.9-fold increase in SIVp28(+) macrophages entering the CNS late compared with those entering early (P CD163(+) macrophage recruitment to the CNS inversely correlated with time to death (P CD163 correlated with CD163(+) macrophage recruitment (P = 0.02). Most perivascular macrophages that comprise SIVE lesions and multinucleated giant cells are present in the CNS early, before SIVE lesions are formed. Most SIV-infected macrophages traffic to the CNS terminally with AIDS. Copyright © 2015 American Society for Investigative Pathology. Published by Elsevier Inc. All rights reserved.

  5. Cholesterol through the Looking Glass

    Science.gov (United States)

    Kristiana, Ika; Luu, Winnie; Stevenson, Julian; Cartland, Sian; Jessup, Wendy; Belani, Jitendra D.; Rychnovsky, Scott D.; Brown, Andrew J.

    2012-01-01

    How cholesterol is sensed to maintain homeostasis has been explained by direct binding to a specific protein, Scap, or through altering the physical properties of the membrane. The enantiomer of cholesterol (ent-cholesterol) is a valuable tool in distinguishing between these two models because it shares nonspecific membrane effects with native cholesterol (nat-cholesterol), but not specific binding interactions. This is the first study to compare ent- and nat-cholesterol directly on major molecular parameters of cholesterol homeostasis. We found that ent-cholesterol suppressed activation of the master transcriptional regulator of cholesterol metabolism, SREBP-2, almost as effectively as nat-cholesterol. Importantly, ent-cholesterol induced a conformational change in the cholesterol-sensing protein Scap in isolated membranes in vitro, even when steps were taken to eliminate potential confounding effects from endogenous cholesterol. Ent-cholesterol also accelerated proteasomal degradation of the key cholesterol biosynthetic enzyme, squalene monooxygenase. Together, these findings provide compelling evidence that cholesterol maintains its own homeostasis not only via direct protein interactions, but also by altering membrane properties. PMID:22869373

  6. Macrophages and Dendritic Cells: Partners in Atherogenesis.

    Science.gov (United States)

    Cybulsky, Myron I; Cheong, Cheolho; Robbins, Clinton S

    2016-02-19

    Atherosclerosis is a complex chronic disease. The accumulation of myeloid cells in the arterial intima, including macrophages and dendritic cells (DCs), is a feature of early stages of disease. For decades, it has been known that monocyte recruitment to the intima contributes to the burden of lesion macrophages. Yet, this paradigm may require reevaluation in light of recent advances in understanding of tissue macrophage ontogeny, their capacity for self-renewal, as well as observations that macrophages proliferate throughout atherogenesis and that self-renewal is critical for maintenance of macrophages in advanced lesions. The rate of atherosclerotic lesion formation is profoundly influenced by innate and adaptive immunity, which can be regulated locally within atherosclerotic lesions, as well as in secondary lymphoid organs, the bone marrow and the blood. DCs are important modulators of immunity. Advances in the past decade have cemented our understanding of DC subsets, functions, hematopoietic origin, gene expression patterns, transcription factors critical for differentiation, and provided new tools for study of DC biology. The functions of macrophages and DCs overlap to some extent, thus it is important to reassess the contributions of each of these myeloid cells taking into account strict criteria of cell identification, ontogeny, and determine whether their key roles are within atherosclerotic lesions or secondary lymphoid organs. This review will highlight key aspect of macrophage and DC biology, summarize how these cells participate in different stages of atherogenesis and comment on complexities, controversies, and gaps in knowledge in the field.

  7. Nanomedicine engulfed by macrophages for targeted tumor therapy

    Science.gov (United States)

    Li, Siwen; Feng, Song; Ding, Li; Liu, Yuxi; Zhu, Qiuyun; Qian, Zhiyu; Gu, Yueqing

    2016-01-01

    Macrophages, exhibiting high intrinsic accumulation and infiltration into tumor tissues, are a novel drug vehicle for directional drug delivery. However, the low drug-loading (DL) capacity and the drug cytotoxicity to the cell vehicle have limited the application of macrophages in tumor therapy. In this study, different drugs involving small molecular and nanoparticle drugs were loaded into intrinsic macrophages to find a better way to overcome these limitations. Their DL capacity and cytotoxicity to the macrophages were first compared. Furthermore, their phagocytic ratio, dynamic distributions, and tumoricidal effects were also investigated. Results indicated that more lipid-soluble molecules and DL particles can be phagocytized by macrophages than hydrophilic ones. In addition, the N-succinyl-N′-octyl chitosan (SOC) DL particles showed low cytotoxicity to the macrophage itself, while the dynamic biodistribution of macrophages engulfed with different particles/small molecules showed similar profiles, mainly excreted from liver to intestine pathway. Furthermore, macrophages loaded with SOC–paclitaxel (PTX) particles exhibited greater therapeutic efficacies than those of macrophages directly carrying small molecular drugs such as doxorubicin and PTX. Interestingly, macrophages displayed stronger targeting ability to the tumor site hypersecreting chemokine in immunocompetent mice in comparison to the tumor site secreting low levels of chemokine in immunodeficiency mice. Finally, results demonstrated that macrophages carrying SOC–PTX are a promising pharmaceutical preparation for tumor-targeted therapy. PMID:27601898

  8. Autophagy regulation in macrophages and neutrophils.

    Science.gov (United States)

    Mihalache, Cristina C; Simon, Hans-Uwe

    2012-07-01

    Autophagy is a conserved proteolytic mechanism that degrades cytoplasmic material including cell organelles. Accumulating evidence exists that autophagy also plays a major role in immunity and inflammation. Specifically, it appears that autophagy protects against infections and inflammation. Here, we review recent work performed in macrophages and neutrophils, which both represent critical phagocytes in mammalians. Copyright © 2012 Elsevier Inc. All rights reserved.

  9. ACAT1-associated Late Endosomes/Lysosomes Significantly Improve Impaired Intracellular Cholesterol Metabolism and the Survival of Niemann-Pick Type C Mice.

    Science.gov (United States)

    Kamikawa, Masashi; Lei, XiaoFeng; Fujiwara, Yukio; Nishitsuji, Kazuchika; Mizuta, Hiroshi; Takeya, Motohiro; Sakashita, Naomi

    2014-05-01

    We previously demonstrated that macrophages exhibit endoplasmic reticulum fragmentation under cholesterol-rich conditions, which results in the generation of acyl-coenzyme A: cholesterol acyltransferase 1 (ACAT1)-associated late endosomes/lysosomes (ACAT1-LE). ACAT1-LE efficiently esterify free cholesterol in loco, even with abnormal egress of free cholesterol from late endosomes. Because impaired free cholesterol transport from late endosomes results in Niemann-Pick type C disease (NPC), the induction of ACAT1-LE is a potential therapeutic intervention for NPC. To examine the effects of ACAT1-LE induction on intracellular cholesterol metabolism, we incubated bone marrow-derived macrophages possessing NPC phenotype (npc1 (-/-)) with methyl-β-cyclodextrin-cholesterol complex (mβCD-cho), a cholesterol donor. Immunofluorescence confocal microscopy revealed that mβCD-cho treatment of npc1 (-/-) macrophages resulted in significant colocalization of signals from ACAT1 and lysosome-associated membrane protein 2, a late endosome/lysosome marker. npc1 (-/-) macrophages contained significant amounts of free cholesterol with negligible amounts of cholesteryl ester, while wild-type macrophages possessed the same amounts of both cholesterols. mβCD-cho treatment also induced marked restoration of cholesterol esterification activity. mβCD-cho administration in neonate npc1 (-/-) mice improved survival. These results indicate that ACAT1-LE induction in npc1 (-/-) mice corrects impaired intracellular cholesterol metabolism and that restoring cholesterol esterification improves prognosis of npc1 (-/-). These data suggest that ACAT1-LE induction is a potential alternative therapeutic strategy for NPC.

  10. Acute sterol o-acyltransferase 2 (SOAT2 knockdown rapidly mobilizes hepatic cholesterol for fecal excretion.

    Directory of Open Access Journals (Sweden)

    Stephanie M Marshall

    Full Text Available The primary risk factor for atherosclerotic cardiovascular disease is LDL cholesterol, which can be reduced by increasing cholesterol excretion from the body. Fecal cholesterol excretion can be driven by a hepatobiliary as well as a non-biliary pathway known as transintestinal cholesterol efflux (TICE. We previously showed that chronic knockdown of the hepatic cholesterol esterifying enzyme sterol O-acyltransferase 2 (SOAT2 increased fecal cholesterol loss via TICE. To elucidate the initial events that stimulate TICE, C57Bl/6 mice were fed a high cholesterol diet to induce hepatic cholesterol accumulation and were then treated for 1 or 2 weeks with an antisense oligonucleotide targeting SOAT2. Within 2 weeks of hepatic SOAT2 knockdown (SOAT2HKD, the concentration of cholesteryl ester in the liver was reduced by 70% without a reciprocal increase in hepatic free cholesterol. The rapid mobilization of hepatic cholesterol stores resulted in a ∼ 2-fold increase in fecal neutral sterol loss but no change in biliary cholesterol concentration. Acute SOAT2HKD increased plasma cholesterol carried primarily in lipoproteins enriched in apoB and apoE. Collectively, our data suggest that acutely reducing SOAT2 causes hepatic cholesterol to be swiftly mobilized and packaged onto nascent lipoproteins that feed cholesterol into the TICE pathway for fecal excretion.

  11. Regulation of Cerebral Cholesterol Metabolism in Alzheimer’s Disease

    OpenAIRE

    Reiss, Allison B; Voloshyna, Iryna

    2012-01-01

    Alzheimer’s disease (AD) is an age-related neurodegenerative disorder that manifests as a progressive loss of memory and deterioration of higher cognitive functions. AD is characterized by accumulation in the brain of the β-amyloid peptide (Aβ) generated by β- and γ-secretase processing of amyloid precursor protein (APP). Epidemiological studies have linked elevated plasma cholesterol and lipoprotein levels in mid-life with AD development. Cholesterol-fed animal models exhibit neuropathologic...

  12. Cholesterol and prostate cancer.

    Science.gov (United States)

    Pelton, Kristine; Freeman, Michael R; Solomon, Keith R

    2012-12-01

    Prostate cancer risk can be modified by environmental factors, however the molecular mechanisms affecting susceptibility to this disease are not well understood. As a result of a series of recently published studies, the steroidal lipid, cholesterol, has emerged as a clinically relevant therapeutic target in prostate cancer. This review summarizes the findings from human studies as well as animal and cell biology models, which suggest that high circulating cholesterol increases risk of aggressive prostate cancer, while cholesterol lowering strategies may confer protective benefit. Relevant molecular processes that have been experimentally tested and might explain these associations are described. We suggest that these promising results now could be applied prospectively to attempt to lower risk of prostate cancer in select populations.

  13. Macrophage CD74 contributes to MIF-induced pulmonary inflammation

    Directory of Open Access Journals (Sweden)

    Al-Abed Yousef

    2009-05-01

    Full Text Available Abstract Background MIF is a critical mediator of the host defense, and is involved in both acute and chronic responses in the lung. Neutralization of MIF reduces neutrophil accumulation into the lung in animal models. We hypothesized that MIF, in the alveolar space, promotes neutrophil accumulation via activation of the CD74 receptor on macrophages. Methods To determine whether macrophage CD74 surface expression contributes MIF-induced neutrophil accumulation, we instilled recombinant MIF (r-MIF into the trachea of mice in the presence or absence of anti-CD74 antibody or the MIF specific inhibitor, ISO-1. Using macrophage culture, we examined the downstream pathways of MIF-induced activation that lead to neutrophil accumulation. Results Intratracheal instillation of r-MIF increased the number of neutrophils as well as the concentration of macrophage inflammatory protein 2 (MIP-2 and keratinocyte-derived chemokine (KC in BAL fluids. CD74 was found to be expressed on the surface of alveolar macrophages, and MIF-induced MIP-2 accumulation was dependent on p44/p42 MAPK in macrophages. Anti-CD74 antibody inhibited MIF-induced p44/p42 MAPK phosphorylation and MIP-2 release by macrophages. Furthermore, we show that anti-CD74 antibody inhibits MIF-induced alveolar accumulation of MIP-2 (control IgG vs. CD74 Ab; 477.1 ± 136.7 vs. 242.2 ± 102.2 pg/ml, p 4 vs. 1.90 ± 0.61 × 104, p Conclusion MIF-induced neutrophil accumulation in the alveolar space results from interaction with CD74 expressed on the surface of alveolar macrophage cells. This interaction induces p44/p42 MAPK activation and chemokine release. The data suggest that MIF and its receptor, CD74, may be useful targets to reduce neutrophilic lung inflammation, and acute lung injury.

  14. Cholesterol and myelin biogenesis.

    Science.gov (United States)

    Saher, Gesine; Simons, Mikael

    2010-01-01

    Myelin consists of several layers of tightly compacted membranes wrapped around axons in the nervous system. The main function of myelin is to provide electrical insulation around the axon to ensure the rapid propagation of nerve conduction. As the myelinating glia terminally differentiates, they begin to produce myelin membranes on a remarkable scale. This membrane is unique in its composition being highly enriched in lipids, in particular galactosylceramide and cholesterol. In this review we will summarize the role of cholesterol in myelin biogenesis in the central and peripheral nervous system.

  15. Orbitofrontal cholesterol granuloma.

    Science.gov (United States)

    Chow, L P; McNab, A A

    2005-02-01

    Cholesterol granuloma of the orbital bones is a rare but readily recognisable condition. It is an osteolytic lesion with a granulomatous reaction surrounding cholesterol crystals, old haemorrhage and a fibrous capsule. There is a male preponderance and it usually occurs in young or middle-aged men. It is treatable with drainage and curettage via an orbitotomy, and craniotomy or wide bone removal is almost never required. Six cases of this condition were reviewed to highlight the typical clinical presentation, computed tomography and magnetic resonance results, and surgical management.

  16. Intestinal cholesterol transport: Measuring cholesterol absorption and its reverse

    NARCIS (Netherlands)

    Jakulj, L.

    2013-01-01

    Intestinal cholesterol transport might serve as an attractive future target for cardiovascular disease reduction, provided that underlying molecular mechanisms are more extensively elucidated, combined with improved techniques to measure changes in cholesterol fluxes and their possible anti-atherosc

  17. Voluntary exercise increases cholesterol efflux but not macrophage reverse cholesterol transport in vivo in mice

    NARCIS (Netherlands)

    Meissner, Maxi; Nijstad, Niels; Kuipers, Folkert; Tietge, Uwe J. F.

    2010-01-01

    Physical exercise beneficially impacts on the plasma lipoprotein profile as well as on the incidence of cardiovascular events and is therefore recommended in primary and secondary prevention strategies against atherosclerotic cardiovascular disease. However, the underlying mechanisms of the

  18. Transintestinal cholesterol efflux

    NARCIS (Netherlands)

    van der Velde, Astrid E.; Brufau, Gemma; Groen, Albert K.

    2010-01-01

    Purpose of review Regulation of cholesterol homeostasis is a complex interplay of a multitude of metabolic pathways situated in different organs. The liver plays a central role and has received most attention of the research community. In this review, we discuss recent progress in the understanding

  19. Cholesterol: Up in Smoke.

    Science.gov (United States)

    Raloff, Janet

    1991-01-01

    Discussed is the contribution cooked meat makes to air pollution. The dozens of compounds, including cholesterol, that are released when a hamburger is grilled are described. The potential effects of these emissions on humans and the urban environment are discussed. (KR)

  20. Regulation of cholesterol homeostasis

    NARCIS (Netherlands)

    van der Wulp, Mariette Y. M.; Verkade, Henkjan J.; Groen, Albert K.

    2013-01-01

    Hypercholesterolemia is an important risk factor for cardiovascular disease. It is caused by a disturbed balance between cholesterol secretion into the blood versus uptake. The pathways involved are regulated via a complex interplay of enzymes, transport proteins, transcription factors and non-codin

  1. Cholesterol transport in model membranes

    Science.gov (United States)

    Garg, Sumit; Porcar, Lionel; Butler, Paul; Perez-Salas, Ursula

    2010-03-01

    Physiological processes distribute cholesterol unevenly within the cell. The levels of cholesterol are maintained by intracellular transport and a disruption in the cell's ability to keep these normal levels will lead to disease. Exchange rates of cholesterol are generally studied in model systems using labeled lipid vesicles. Initially donor vesicles have all the cholesterol and acceptor vesicles are devoid of it. They are mixed and after some time the vesicles are separated and cholesterol is traced in each vesicle. The studies performed up to date have significant scatter indicating that the methodologies are not consistent. The present work shows in-situ Time-Resolved SANS studies of cholesterol exchange rates in unsaturated PC lipid vesicles. Molecular dynamics simulations were done to investigate the energetic and kinetic behavior of cholesterol in this system. This synergistic approach will provide insight into our efforts to understand cholesterol traffic.

  2. Mitochondrial function and regulation of macrophage sterol metabolism and inflammatory responses

    Institute of Scientific and Technical Information of China (English)

    Annette; Graham; Anne-Marie; Allen

    2015-01-01

    The aim of this review is to explore the role of mitochondria in regulating macrophage sterol homeostasis and inflammatory responses within the aetiology of atherosclerosis.Macrophage generation of oxysterol activators of liver X receptors(LXRs),via sterol 27-hydroxylase,is regulated by the rate of flux of cholesterolto the inner mitochondrial membrane,via a complex of cholesterol trafficking proteins.Oxysterols are key signalling molecules,regulating the transcriptional activity of LXRs which coordinate macrophage sterol metabolism and cytokine production,key features influencing the impact of these cells within atherosclerotic lesions.The precise identity of the complex of proteins mediating mitochondrial cholesterol trafficking in macrophages remains a matter of debate,but may include steroidogenic acute regulatory protein and translocator protein.There is clear evidence that targeting either of these proteins enhances removal of cholesterol via LXRα-dependent induction of ATP binding cassette transporters(ABCA1,ABCG1) and limits the production of inflammatory cytokines; interventions which influence mitochondrial structure and bioenergetics also impact on removal of cholesterol from macrophages.Thus,molecules which can sustain or improve mitochondrial structure,the function of the electron transport chain,or increase the activity of components of the protein complex involved in cholesterol transfer,may therefore have utility in limiting or regressing atheroma development,reducing the incidence of coronary heart disease and myocardial infarction.

  3. Intestine-specific MTP and global ACAT2 deficiency lowers acute cholesterol absorption with chylomicrons and HDLs.

    Science.gov (United States)

    Iqbal, Jahangir; Boutjdir, Mohamed; Rudel, Lawrence L; Hussain, M Mahmood

    2014-11-01

    Intestinal cholesterol absorption involves the chylomicron and HDL pathways and is dependent on microsomal triglyceride transfer protein (MTP) and ABCA1, respectively. Chylomicrons transport free and esterified cholesterol, whereas HDLs transport free cholesterol. ACAT2 esterifies cholesterol for secretion with chylomicrons. We hypothesized that free cholesterol accumulated during ACAT2 deficiency may be secreted with HDLs when chylomicron assembly is blocked. To test this, we studied cholesterol absorption in mice deficient in intestinal MTP, global ACAT2, and both intestinal MTP and global ACAT2. Intestinal MTP ablation significantly increased intestinal triglyceride and cholesterol levels and reduced their transport with chylomicrons. In contrast, global ACAT2 deficiency had no effect on triglyceride absorption but significantly reduced cholesterol absorption with chylomicrons and increased cellular free cholesterol. Their combined deficiency reduced cholesterol secretion with both chylomicrons and HDLs. Thus, contrary to our hypothesis, free cholesterol accumulated in the absence of MTP and ACAT2 is unavailable for secretion with HDLs. Global ACAT2 deficiency causes mild hypertriglyceridemia and reduces hepatosteatosis in mice fed high cholesterol diets by increasing hepatic lipoprotein production by unknown mechanisms. We show that this phenotype is preserved in the absence of intestinal MTP in global ACAT2-deficient mice fed a Western diet. Further, we observed increases in hepatic MTP activity in these mice. Thus, ACAT2 deficiency might increase MTP expression to avoid hepatosteatosis in cholesterol-fed animals. Therefore, ACAT2 inhibition might avert hepatosteatosis associated with high cholesterol diets by increasing hepatic MTP expression and lipoprotein production.

  4. Cholesterol excretion and colon cancer.

    Science.gov (United States)

    Broitman, S A

    1981-09-01

    Populations consuming diets high in fat and cholesterol exhibit a greater incidence of colon cancer than those consuming less fat and cholesterol. Lowering elevated serum cholesterol levels experimentally or clinically is associated with increased large-bowel tumorigenesis. Thus, cholesterol lost to the gut, either dietary or endogenously synthesized, appears to have a role in large-bowel cancer. Whether the effect(s) is mediated by increases in fecal bile acid excretion or some other mechanism is not clear.

  5. Toxicity of mercury in macrophages. Structure and function of macrophages after experimental mercury exposure

    Energy Technology Data Exchange (ETDEWEB)

    Christensen, M.M.

    1995-12-31

    Mercury is recognized as an environmental heavy metal pollutant with a toxic effect on living organisms. The toxicity of this heavy metal at cellular level is described for many types of cells. Macrophages are ubiquitous in the organism and play a central role in the non-specific defence barrier against intruding micro-organisms. As a first line of defence, macrophages are crucial for the course of generalized infection, for instance with herpes simplex virus. Functions such as phagocytosis, migration, activation during infection and cytokine production are important in this context. Mercury, detectable by auto metallography, is found in the lysosomes of macrophages and this accumulation is dependent upon dose and length of time of mercury exposure. But higher concentrations cause auto interference, which indicates that mercury accumulation is dependent on lysosome functional integrity and that mercury inhibits lysosome functions. In mice intraperitoneally exposed to mercury chloride, mercury is found localized in the lysosomes of macrophages in the spleen, thymus, lymph nodes and liver as well as in peritoneal macrophages. The effect of mercury on a virus infection was examined in studies of the course of infection in mice treated with mercury and infected with herpes simplex virus type 2 (HSV-2) under further exposure to mercury. To further elucidate aspects of interactions between heavy metals and macrophages and their eventual significance for the antiviral effect of macrophages, the effect of mercury on cell respiratory burst capacity and the influence of mercury on cell production of and reaction to cytokines was examined. This thesis shows that mercury is immunotoxic in that it affects macrophages both with regard to the viability and function of the cells. This is also valid for mercury concentrations that do not result in apparent pathological changes. (EG) 98 refs.

  6. Mice lacking lipid droplet-associated hydrolase, a gene linked to human prostate cancer, have normal cholesterol ester metabolism

    DEFF Research Database (Denmark)

    Kory, Nora; Grond, Susanne; Kamat, Siddhesh S

    2017-01-01

    , such as triacylglycerols and sterol esters, as precursors for membrane components and as reservoirs of metabolic energy. LDAH is reported to hydrolyze cholesterol esters and to be important in macrophage cholesterol ester metabolism. Here, we confirm that LDAH is localized to LDs in several model systems. We generated...... a murine model in which Ldah is disrupted but found no evidence for a major function of LDAH in cholesterol ester or triacylglycerol metabolism in vivo, nor a role in energy or glucose metabolism. Our data suggest that LDAH is not a major cholesterol ester hydrolase, and an alternative metabolic function...

  7. How to Get Your Cholesterol Tested

    Science.gov (United States)

    ... Thromboembolism Aortic Aneurysm More How To Get Your Cholesterol Tested Updated:Apr 3,2017 Cholesterol plays a ... factors for heart disease and stroke . How is cholesterol tested? A cholesterol screening measures your level of ...

  8. Cholesterol crystal embolism (atheroembolism)

    Science.gov (United States)

    VENTURELLI, CHIARA; JEANNIN, GUIDO; SOTTINI, LAURA; DALLERA, NADIA; SCOLARI, FRANCESCO

    2006-01-01

    Cholesterol crystal embolism, known as atheroembolic disease, is caused by showers of cholesterol crystals from an atherosclerotic plaque that occludes small arteries. Embolization can occur spontaneously or as an iatrogenic complication from an invasive vascular procedure (angiography or vascular surgery) and after anticoagulant therapy. The atheroembolism can give rise to different degrees of renal impairment. Some patients show a moderate loss of renal function, others severe renal failure requiring dialysis. Renal outcome can be variable: some patients deteriorate or remain on dialysis, some improve and some remain with chronic renal impairment. Clinically, three types of atheroembolic renal disease have been described: acute, subacute or chronic. More frequently a progressive loss of renal function occurs over weeks. Atheroembolization can involve the skin, gastrointestinal system and central nervous system. The diagnosis is difficult and controversial for the protean extrarenal manifestations. In the past, the diagnosis was often made post-mortem. In the last 10 yrs, awareness of atheroembolic renal disease has improved. The correct diagnosis requires the clinician to be alert. The typical patient is a white male aged >60 yrs with a history of hypertension, smoking and arterial disease. The presence of a classic triad (precipitating event, renal failure and peripheral cholesterol crystal embolization) suggests the diagnosis. This can be confirmed by a biopsy of the target organs. A specific treatment is lacking; however, it is an important diagnosis to make because an aggressive therapeutic approach can be associated with a more favorable clinical outcome. PMID:21977265

  9. Bacterial colonization of host cells in the absence of cholesterol.

    Directory of Open Access Journals (Sweden)

    Stacey D Gilk

    2013-01-01

    Full Text Available Reports implicating important roles for cholesterol and cholesterol-rich lipid rafts in host-pathogen interactions have largely employed sterol sequestering agents and biosynthesis inhibitors. Because the pleiotropic effects of these compounds can complicate experimental interpretation, we developed a new model system to investigate cholesterol requirements in pathogen infection utilizing DHCR24(-/- mouse embryonic fibroblasts (MEFs. DHCR24(-/- MEFs lack the Δ24 sterol reductase required for the final enzymatic step in cholesterol biosynthesis, and consequently accumulate desmosterol into cellular membranes. Defective lipid raft function by DHCR24(-/- MEFs adapted to growth in cholesterol-free medium was confirmed by showing deficient uptake of cholera-toxin B and impaired signaling by epidermal growth factor. Infection in the absence of cholesterol was then investigated for three intracellular bacterial pathogens: Coxiella burnetii, Salmonella enterica serovar Typhimurium, and Chlamydia trachomatis. Invasion by S. Typhimurium and C. trachomatis was unaltered in DHCR24(-/- MEFs. In contrast, C. burnetii entry was significantly decreased in -cholesterol MEFs, and also in +cholesterol MEFs when lipid raft-associated α(Vβ(3 integrin was blocked, suggesting a role for lipid rafts in C. burnetii uptake. Once internalized, all three pathogens established their respective vacuolar niches and replicated normally. However, the C. burnetii-occupied vacuole within DHCR24(-/- MEFs lacked the CD63-positive material and multilamellar membranes typical of vacuoles formed in wild type cells, indicating cholesterol functions in trafficking of multivesicular bodies to the pathogen vacuole. These data demonstrate that cholesterol is not essential for invasion and intracellular replication by S. Typhimurium and C. trachomatis, but plays a role in C. burnetii-host cell interactions.

  10. Bacterial Colonization of Host Cells in the Absence of Cholesterol

    Science.gov (United States)

    Gilk, Stacey D.; Cockrell, Diane C.; Luterbach, Courtney; Hansen, Bryan; Knodler, Leigh A.; Ibarra, J. Antonio; Steele-Mortimer, Olivia; Heinzen, Robert A.

    2013-01-01

    Reports implicating important roles for cholesterol and cholesterol-rich lipid rafts in host-pathogen interactions have largely employed sterol sequestering agents and biosynthesis inhibitors. Because the pleiotropic effects of these compounds can complicate experimental interpretation, we developed a new model system to investigate cholesterol requirements in pathogen infection utilizing DHCR24−/− mouse embryonic fibroblasts (MEFs). DHCR24−/− MEFs lack the Δ24 sterol reductase required for the final enzymatic step in cholesterol biosynthesis, and consequently accumulate desmosterol into cellular membranes. Defective lipid raft function by DHCR24−/− MEFs adapted to growth in cholesterol-free medium was confirmed by showing deficient uptake of cholera-toxin B and impaired signaling by epidermal growth factor. Infection in the absence of cholesterol was then investigated for three intracellular bacterial pathogens: Coxiella burnetii, Salmonella enterica serovar Typhimurium, and Chlamydia trachomatis. Invasion by S. Typhimurium and C. trachomatis was unaltered in DHCR24−/− MEFs. In contrast, C. burnetii entry was significantly decreased in −cholesterol MEFs, and also in +cholesterol MEFs when lipid raft-associated αVβ3 integrin was blocked, suggesting a role for lipid rafts in C. burnetii uptake. Once internalized, all three pathogens established their respective vacuolar niches and replicated normally. However, the C. burnetii-occupied vacuole within DHCR24−/− MEFs lacked the CD63-postive material and multilamellar membranes typical of vacuoles formed in wild type cells, indicating cholesterol functions in trafficking of multivesicular bodies to the pathogen vacuole. These data demonstrate that cholesterol is not essential for invasion and intracellular replication by S. Typhimurium and C. trachomatis, but plays a role in C. burnetii-host cell interactions. PMID:23358892

  11. Cholesterol binding to ion channels

    Directory of Open Access Journals (Sweden)

    Irena eLevitan

    2014-02-01

    Full Text Available Numerous studies demonstrated that membrane cholesterol is a major regulator of ion channel function. The goal of this review is to discuss significant advances that have been recently achieved in elucidating the mechanisms responsible for cholesterol regulation of ion channels. The first major insight that comes from growing number of studies that based on the sterol specificity of cholesterol effects, show that several types of ion channels (nAChR, Kir, BK, TRPV are regulated by specific sterol-protein interactions. This conclusion is supported by demonstrating direct saturable binding of cholesterol to a bacterial Kir channel. The second major advance in the field is the identification of putative cholesterol binding sites in several types of ion channels. These include sites at locations associated with the well-known cholesterol binding motif CRAC and its reversed form CARC in nAChR, BK, and TRPV, as well as novel cholesterol binding regions in Kir channels. Notably, in the majority of these channels, cholesterol is suggested to interact mainly with hydrophobic residues in non-annular regions of the channels being embedded in between transmembrane protein helices. We also discuss how identification of putative cholesterol binding sites is an essential step to understand the mechanistic basis of cholesterol-induced channel regulation. Clearly, however, these are only the first few steps in obtaining a general understanding of cholesterol-ion channels interactions and their roles in cellular and organ functions.

  12. Impact of high cholesterol in a Parkinson's disease model: Prevention of lysosomal leakage versus stimulation of α-synuclein aggregation.

    Science.gov (United States)

    Eriksson, Ida; Nath, Sangeeta; Bornefall, Per; Giraldo, Ana Maria Villamil; Öllinger, Karin

    2017-03-01

    Parkinson's disease is characterized by accumulation of intraneuronal cytoplasmic inclusions, Lewy bodies, which mainly consist of aggregated α-synuclein. Controversies exist as to whether high blood cholesterol is a risk factor for the development of the disease and whether statin treatment could have a protective effect. Using a model system of BE(2)-M17 neuroblastoma cells treated with the neurotoxin 1-methyl-4-phenylpyridinium (MPP(+)), we found that MPP(+)-induced cell death was accompanied by cholesterol accumulation in a lysosomal-like pattern in pre-apoptotic cells. To study the effects of lysosomal cholesterol accumulation, we increased lysosomal cholesterol through pre-treatment with U18666A and found delayed leakage of lysosomal contents into the cytosol, which reduced cell death. This suggests that increased lysosomal cholesterol is a stress response mechanism to protect lysosomal membrane integrity in response to early apoptotic stress. However, high cholesterol also stimulated the accumulation of α-synuclein. Treatment with the cholesterol-lowering drug lovastatin reduced MPP(+)-induced cell death by inhibiting the production of reactive oxygen species, but did not prevent lysosomal cholesterol increase nor affect α-synuclein accumulation. Our study indicates a dual role of high cholesterol in Parkinson's disease, in which it acts both as a protector against lysosomal membrane permeabilization and as a stimulator of α-synuclein accumulation. Copyright © 2017 Elsevier GmbH. All rights reserved.

  13. Association between blood cholesterol level with periodontal status of coronary heart disease patients

    Science.gov (United States)

    Valensia, Rosy; Masulili, Sri Lelyati C.; Lessang, Robert; Radi, Basuni

    2017-02-01

    Coronary heart disease (CHD) is an abnormal narrowing of heart arteries associated with local accumulation of lipids, in the form of cholesterol and triglycerides. Periodontal disease is a chronic inflammatory that suggests link to the development of CHD. In periodontitis have been reported changes in lipid profile, include increased of cholesterol levels of blood. Objective: to analyse correlation between blood cholesterol level with periodontal status of CHD and non CHD subjects. Methods: Periodontal status and blood cholesterol level of 60 CHD and 40 non CHD subjects was measured. Result: Blood cholesterol level in CHD subjects differs from non CHD subjects (p=0.032). Blood cholesterol level correlates with pocket depth (p=0.003) and clinical attachment loss (CAL) (p=0.000) in CHD subjects. Blood cholesterol level correlates with pocket depth (p=0.010) in non CHD subjects. There is no significant correlation between blood cholesterol level and bleeding on probing (BOP) in CHD subjects. There is no significant correlation between blood cholesterol level with BOP and CAL in non CHD subjects. Conclusion: Blood cholesterol level in control group is higher than CHD patients. Blood cholesterol level positively associated with pocket depth (r=0.375) and CAL (r=0.450) in CHD patients. Blood cholesterol level is positively associated with pocket depth (r=0.404) in control group.

  14. Trypanosoma cruzi Epimastigotes Are Able to Manage Internal Cholesterol Levels under Nutritional Lipid Stress Conditions

    Science.gov (United States)

    Pereira, Miria Gomes; Visbal, Gonzalo; Salgado, Leonardo T.; Vidal, Juliana Cunha; Godinho, Joseane L. P.; De Cicco, Nuccia N. T.; Atella, Geórgia C.; de Souza, Wanderley; Cunha-e-Silva, Narcisa

    2015-01-01

    Trypanosoma cruzi epimastigotes store high amounts of cholesterol and cholesteryl esters in reservosomes. These unique organelles are responsible for cellular digestion by providing substrates for homeostasis and parasite differentiation. Here we demonstrate that under nutritional lipid stress, epimastigotes preferentially mobilized reservosome lipid stocks, instead of lipid bodies, leading to the consumption of parasite cholesterol reservoirs and production of ergosterol. Starved epimastigotes acquired more LDL-NBD-cholesterol by endocytosis and distributed the exogenous cholesterol to their membranes faster than control parasites. Moreover, the parasites were able to manage internal cholesterol levels, alternating between consumption and accumulation. With normal lipid availability, parasites esterified cholesterol exhibiting an ACAT-like activity that was sensitive to Avasimibe in a dose-dependent manner. This result also implies that exogenous cholesterol has a role in lipid reservoirs in epimastigotes. PMID:26068009

  15. Cholesterol sulfate in human physiology: what's it all about?

    Science.gov (United States)

    Strott, Charles A; Higashi, Yuko

    2003-07-01

    Cholesterol sulfate is quantitatively the most important known sterol sulfate in human plasma, where it is present in a concentration that overlaps that of the other abundant circulating steroid sulfate, dehydroepiandrosterone (DHEA) sulfate. Although these sulfolipids have similar production and metabolic clearance rates, they arise from distinct sources and are metabolized by different pathways. While the function of DHEA sulfate remains an enigma, cholesterol sulfate has emerged as an important regulatory molecule. Cholesterol sulfate is a component of cell membranes where it has a stabilizing role, e.g., protecting erythrocytes from osmotic lysis and regulating sperm capacitation. It is present in platelet membranes where it supports platelet adhesion. Cholesterol sulfate can regulate the activity of serine proteases, e.g., those involved in blood clotting, fibrinolysis, and epidermal cell adhesion. As a result of its ability to regulate the activity of selective protein kinase C isoforms and modulate the specificity of phosphatidylinositol 3-kinase, cholesterol sulfate is involved in signal transduction. Cholesterol sulfate functions in keratinocyte differentiation, inducing genes that encode for key components involved in development of the barrier. The accumulating evidence demonstrating a regulatory function for cholesterol sulfate appears solid; the challenge now is to work out the molecular mechanisms whereby this interesting molecule carries out its various roles.

  16. Proinsulin-producing, hyperglycemia-induced adipose tissue macrophages underlie insulin resistance in high fat-fed diabetic mice

    Science.gov (United States)

    Adipose tissue macrophages play an important role in the pathogenesis of obese type 2 diabetes. High-fat diet-induced obesity has been shown to lead to adipose tissue macrophages accumulation in rodents;however, the impact of hyperglycemia on adipose tissue macrophages dynamics in high-fat diet-fed ...

  17. LXRß is the dominant LXR subtype in skeletal muscle regulating lipogenesis and cholesterol efflux

    NARCIS (Netherlands)

    Hessvik, N.P.; Boekschoten, M.V.; Baltzersen, M.A.; Kersten, A.H.; Xu, X.; Andersen, H.E.; Rustan, A.C.; Thoresen, G.H.

    2010-01-01

    Liver X receptors (LXRs) are important regulators of cholesterol, lipid, and glucose metabolism and have been extensively studied in liver, macrophages, and adipose tissue. However, their role in skeletal muscle is poorly studied and the functional role of each of the LXR and LXRß subtypes in skelet

  18. Sensitivity to lysosome-dependent cell death is directly regulated by lysosomal cholesterol content.

    Directory of Open Access Journals (Sweden)

    Hanna Appelqvist

    Full Text Available Alterations in lipid homeostasis are implicated in several neurodegenerative diseases, although the mechanisms responsible are poorly understood. We evaluated the impact of cholesterol accumulation, induced by U18666A, quinacrine or mutations in the cholesterol transporting Niemann-Pick disease type C1 (NPC1 protein, on lysosomal stability and sensitivity to lysosome-mediated cell death. We found that neurons with lysosomal cholesterol accumulation were protected from oxidative stress-induced apoptosis. In addition, human fibroblasts with cholesterol-loaded lysosomes showed higher lysosomal membrane stability than controls. Previous studies have shown that cholesterol accumulation is accompanied by the storage of lipids such as sphingomyelin, glycosphingolipids and sphingosine and an up regulation of lysosomal associated membrane protein-2 (LAMP-2, which may also influence lysosomal stability. However, in this study the use of myriocin and LAMP deficient fibroblasts excluded these factors as responsible for the rescuing effect and instead suggested that primarily lysosomal cholesterol content determineD the cellular sensitivity to toxic insults. Further strengthening this concept, depletion of cholesterol using methyl-β-cyclodextrin or 25-hydroxycholesterol decreased the stability of lysosomes and cells became more prone to undergo apoptosis. In conclusion, cholesterol content regulated lysosomal membrane permeabilization and thereby influenced cell death sensitivity. Our data suggests that lysosomal cholesterol modulation might be used as a therapeutic strategy for conditions associated with accelerated or repressed apoptosis.

  19. Nanomedicine engulfed by macrophages for targeted tumor therapy

    Directory of Open Access Journals (Sweden)

    Li S

    2016-08-01

    Full Text Available Siwen Li,1,* Song Feng,1,* Li Ding,1 Yuxi Liu,1 Qiuyun Zhu,1 Zhiyu Qian,2 Yueqing Gu1 1Department of Biomedical Engineering, China Pharmaceutical University, 2Department of Biomedical Engineering, School of Automation, Nanjing University of Aeronautics and Astronautics, Nanjing, Jiangsu, People’s Republic of China *These authors contributed equally to this work Abstract: Macrophages, exhibiting high intrinsic accumulation and infiltration into tumor tissues, are a novel drug vehicle for directional drug delivery. However, the low drug-loading (DL capacity and the drug cytotoxicity to the cell vehicle have limited the application of macrophages in tumor therapy. In this study, different drugs involving small molecular and nanoparticle drugs were loaded into intrinsic macrophages to find a better way to overcome these limitations. Their DL capacity and cytotoxicity to the macrophages were first compared. Furthermore, their phagocytic ratio, dynamic distributions, and tumoricidal effects were also investigated. Results indicated that more lipid-soluble molecules and DL particles can be phagocytized by macrophages than hydrophilic ones. In addition, the N-succinyl-N'-octyl chitosan (SOC DL particles showed low cytotoxicity to the macrophage itself, while the dynamic biodistribution of macrophages engulfed with different particles/small molecules showed similar profiles, mainly excreted from liver to intestine pathway. Furthermore, macrophages loaded with SOC–paclitaxel (PTX particles exhibited greater therapeutic efficacies than those of macrophages directly carrying small molecular drugs such as doxorubicin and PTX. Interestingly, macrophages displayed stronger targeting ability to the tumor site hypersecreting chemokine in immunocompetent mice in comparison to the tumor site secreting low levels of chemokine in immunodeficiency mice. Finally, results demonstrated that macrophages carrying SOC–PTX are a promising pharmaceutical preparation

  20. J774 macrophages secrete antibiotics via organic anion transporters.

    Science.gov (United States)

    Cao, C X; Silverstein, S C; Neu, H C; Steinberg, T H

    1992-02-01

    Mouse macrophages and J774 macrophage-like cells express probenecid-inhibitable organic anion transporters that remove anionic dyes from the cells' cytoplasmic matrix and secrete these dyes into the extracellular medium. The present studies show that these transporters also secrete antibiotics from J774 macrophages. Penicillin G permeates J774 cells poorly, but after it was introduced into the cell cytoplasm, it was secreted in a probenecid-inhibitable fashion. The quinolone norfloxacin enters macrophages readily. Probenecid retarded the secretion of intracellular norfloxacin by J774 cells and enhanced norfloxacin accumulation three- to fourfold. Thus the intracellular accumulation of norfloxacin is regulated in part by organic anion transporters that secrete norfloxacin (and penicillin G) from J774 cells. This transport process may have clinical significance, as fluoroquinolones inhibit growth of intracellular pathogens such as mycobacteria and Brucella organisms in vitro but fail to arrest infections with these organisms in vivo.

  1. Identification of an autophagy defect in smokers' alveolar macrophages.

    Science.gov (United States)

    Monick, Martha M; Powers, Linda S; Walters, Katherine; Lovan, Nina; Zhang, Michael; Gerke, Alicia; Hansdottir, Sif; Hunninghake, Gary W

    2010-11-01

    Alveolar macrophages are essential for clearing bacteria from the alveolar surface and preventing microbe-induced infections. It is well documented that smokers have an increased incidence of infections, in particular lung infections. Alveolar macrophages accumulate in smokers' lungs, but they have a functional immune deficit. In this study, we identify an autophagy defect in smokers' alveolar macrophages. Smokers' alveolar macrophages accumulate both autophagosomes and p62, a marker of autophagic flux. The decrease in the process of autophagy leads to impaired protein aggregate clearance, dysfunctional mitochondria, and defective delivery of bacteria to lysosomes. This study identifies the autophagy pathway as a potential target for interventions designed to decrease infection rates in smokers and possibly in individuals with high environmental particulate exposure.

  2. Plasma lipoproteins and monocyte-macrophages in a peroxisome-deficient system: study of a patient with infantile refsum disease.

    Science.gov (United States)

    Mandel, H; Berant, M; Meiron, D; Aizin, A; Oiknine, J; Brook, J G; Aviram, M

    1992-01-01

    Hypocholesterolaemia in infantile Refsum disease (IRD) may link peroxisomes and lipoprotein metabolism. In our patient, plasma cholesterol levels were reduced to 26% and 29% of control in LDL and HDL fractions, respectively. Plasma apolipoproteins B-100 and A-I levels were 52% and 66% of controls, respectively. In the kindred, plasma cholesterol concentration was 61-73% of controls. The HDL-cholesterol/apo A-I ratios were: patient 0.12; kindred 0.17; controls 0.28. Analysis of the IRD patient's lipoprotein revealed compositional abnormalities in all fractions. The patient's LDL demonstrated a substantial reduction in its lipid-to-protein ratio. Alterations in plasma lipoproteins affect their interaction with macrophages. Upon incubation of the patient's LDL with J-774 macrophages, its cellular uptake, measured as cholesterol esterification rate, was only 66% of a control rate. The abnormal LDL of the IRD patient showed also only 25% of control susceptibility to in vitro oxidation. Studies of cellular cholesterol metabolism in the patient's monocyte-derived macrophages (MDM) showed 57% increased cholesterol esterification rate in comparison to normal MDM. The possible link between lipoprotein abnormalities and monocyte-macrophage cholesterol metabolism is discussed.

  3. Regulation of reverse cholesterol transport - a comprehensive appraisal of available animal studies

    Directory of Open Access Journals (Sweden)

    Annema Wijtske

    2012-03-01

    Full Text Available Abstract Plasma levels of high density lipoprotein (HDL cholesterol are strongly inversely correlated to the risk of atherosclerotic cardiovascular disease. A major recognized functional property of HDL particles is to elicit cholesterol efflux and consequently mediate reverse cholesterol transport (RCT. The recent introduction of a surrogate method aiming at determining specifically RCT from the macrophage compartment has facilitated research on the different components and pathways relevant for RCT. The current review provides a comprehensive overview of studies carried out on macrophage-specific RCT including a quick reference guide of available data. Knowledge and insights gained on the regulation of the RCT pathway are summarized. A discussion of methodological issues as well as of the respective relevance of specific pathways for RCT is also included.

  4. The effect of dietary rape-seed oil on cholesterol-ester metabolism and cholesterol-ester-hydrolase activity in the rat adrenal.

    Science.gov (United States)

    Beckett, G J; Boyd, G S

    1975-05-06

    The effects of stock diet and stock diet supplemented by olive oil and rape seed on rat adrenal cholesterol ester metabolism have been studied. Rats fed rape seed oil failed to gain weight at the same rate as rats fed olive oil. A prominent feature of the rats fed rape seed oil was an accumulation of high concentrations of cholesterol erucate in the adrenal lipid droplets. When these rats were subjected to an ether stress no percentage decrease in the amount of cholesterol erucate was observed. Adrenal cholesterol ester hydrolase activity was higher in rats fed the olive oil and rape seed oil diets than rats fed the stock diet. In rats fed stock or olive oil diets, a ten-minute ether anaesthesia stress resulted in a two-fold increase in activity of adrenal cholesterol ester hydrolase. Cofactor addition of ATP, cyclic AMP and MgCl-2 in vitro resulted in a stimulation of cholesterol ester hydrolase to a similar activity in both quiescent and ether-stressed rats. By contrast rats fed the rape seed oil diet gave no significant stimulation of cholesterol ester hydrolase activity when given an ether stress or when cofactors were added in vitro. Cholesterol erucate was hydrolysed at only 25% to 30% of the rate of cholesterol oleate in vitro in all groups of animals. Oleic acid added in vitro gave an inhibition of cholesterol ester hydrolase activity in rats fed stock diet while erucic acid activated the enzyme. The accumulation of cholesterol erucate in the adrenal when rats are fed rape seed oil could be due to the reduced ability of cholesterol ester hydrolase to hydrolyse this ester.

  5. Characterization of placental cholesterol transport

    DEFF Research Database (Denmark)

    Lindegaard, Marie L; Wassif, Christopher A; Vaisman, Boris

    2008-01-01

    Patients with Smith-Lemli-Opitz syndrome (SLOS) are born with multiple congenital abnormalities. Postnatal cholesterol supplementation is provided; however, it cannot correct developmental malformations due to in utero cholesterol deficit. Increased transport of cholesterol from maternal to fetal...... circulation might attenuate congenital malformations. The cholesterol transporters Abca1, Abcg1, and Sr-b1 are present in placenta; however, their potential role in placental transport remains undetermined. In mice, expression analyses showed that Abca1 and Abcg1 transcripts increased 2-3-fold between...... embryonic days 13.5 and 18.5 in placental tissue; whereas, Sr-b1 expression decreased. To examine the functional role of Abca1, Abcg1 and Sr-b1 we measured the maternal-fetal transfer of (14)C-cholesterol in corresponding mutant embryos. Disruption of either Abca1 or Sr-b1 decreased cholesterol transfer...

  6. Retrograde cholesterol transport in the human Caco-2/TC7 cell line: a model to study trans-intestinal cholesterol excretion in atherogenic and diabetic dyslipidemia.

    Science.gov (United States)

    Dugardin, Camille; Briand, Olivier; Touche, Véronique; Schonewille, Marleen; Moreau, François; Le May, Cédric; Groen, Albert K; Staels, Bart; Lestavel, Sophie

    2017-02-01

    The dyslipidemia associated with type 2 diabetes is a major risk factor for the development of atherosclerosis. Trans-intestinal cholesterol excretion (TICE) has recently been shown to contribute, together with the classical hepatobiliary route, to fecal cholesterol excretion and cholesterol homeostasis. The aim of this study was to develop an in vitro cell model to investigate enterocyte-related processes of TICE. Differentiated Caco-2/TC7 cells were grown on transwells and incubated basolaterally (blood side) with human plasma and apically (luminal side) with lipid micelles. Radioactive and fluorescent cholesterol tracers were used to investigate cholesterol uptake at the basolateral membrane, intracellular distribution and apical excretion. Our results show that cholesterol is taken up at the basolateral membrane, accumulates intracellularly as lipid droplets and undergoes a cholesterol acceptor-facilitated and progressive excretion through the apical membrane of enterocytes. The overall process is abolished at 4 °C, suggesting a biologically active phenomenon. Moreover, this trans-enterocytic retrograde cholesterol transport displays some TICE features like modulation by PCSK9 and an ABCB1 inhibitor. Finally, we highlight the involvement of microtubules in the transport of plasma cholesterol from basolateral to apical pole of enterocytes. The human Caco-2/TC7 cell line appears a good in vitro model to investigate the enterocytic molecular mechanisms of TICE, which may help to identify intestinal molecular targets to enhance reverse cholesterol transport and fight against dyslipidemia.

  7. Cholesterol impairment contributes to neuroserpin aggregation

    Science.gov (United States)

    Giampietro, Costanza; Lionetti, Maria Chiara; Costantini, Giulio; Mutti, Federico; Zapperi, Stefano; La Porta, Caterina A. M.

    2017-01-01

    Intraneural accumulation of misfolded proteins is a common feature of several neurodegenerative pathologies including Alzheimer’s and Parkinson’s diseases, and Familial Encephalopathy with Neuroserpin Inclusion Bodies (FENIB). FENIB is a rare disease due to a point mutation in neuroserpin which accelerates protein aggregation in the endoplasmic reticulum (ER). Here we show that cholesterol depletion induced either by prolonged exposure to statins or by inhibiting the sterol reg-ulatory binding-element protein (SREBP) pathway also enhances aggregation of neuroserpin proteins. These findings can be explained considering a computational model of protein aggregation under non-equilibrium conditions, where a decrease in the rate of protein clearance improves aggregation. Decreasing cholesterol in cell membranes affects their biophysical properties, including their ability to form the vesicles needed for protein clearance, as we illustrate by a simple mathematical model. Taken together, these results suggest that cholesterol reduction induces neuroserpin aggregation, even in absence of specific neuroserpin mutations. The new mechanism we uncover could be relevant also for other neurodegenerative diseases associated with protein aggregation. PMID:28255164

  8. Cholesterol impairment contributes to neuroserpin aggregation

    Science.gov (United States)

    Giampietro, Costanza; Lionetti, Maria Chiara; Costantini, Giulio; Mutti, Federico; Zapperi, Stefano; La Porta, Caterina A. M.

    2017-03-01

    Intraneural accumulation of misfolded proteins is a common feature of several neurodegenerative pathologies including Alzheimer’s and Parkinson’s diseases, and Familial Encephalopathy with Neuroserpin Inclusion Bodies (FENIB). FENIB is a rare disease due to a point mutation in neuroserpin which accelerates protein aggregation in the endoplasmic reticulum (ER). Here we show that cholesterol depletion induced either by prolonged exposure to statins or by inhibiting the sterol reg-ulatory binding-element protein (SREBP) pathway also enhances aggregation of neuroserpin proteins. These findings can be explained considering a computational model of protein aggregation under non-equilibrium conditions, where a decrease in the rate of protein clearance improves aggregation. Decreasing cholesterol in cell membranes affects their biophysical properties, including their ability to form the vesicles needed for protein clearance, as we illustrate by a simple mathematical model. Taken together, these results suggest that cholesterol reduction induces neuroserpin aggregation, even in absence of specific neuroserpin mutations. The new mechanism we uncover could be relevant also for other neurodegenerative diseases associated with protein aggregation.

  9. Cholesterol Embolism: An Overlooked Diagnosis

    Directory of Open Access Journals (Sweden)

    Sinem Nihal ESATOĞLU

    2012-01-01

    Full Text Available Acute renal failure following angiography is usually due to radiocontrast nephropathy; however, cholesterol embolism should be kept in mind when making the differential diagnosis. Cholesterol embolism is a multisystem disease, usually seen in elderly men who have severe atherosclerosis. In this case report, we describe a patient with cholesterol embolism who had a typical clinical history of progressive renal failure. We hope that this case report will emphasize the importance of this overlooked syndrome.

  10. Cytomegalovirus Restructures Lipid Rafts via a US28/CDC42-Mediated Pathway, Enhancing Cholesterol Efflux from Host Cells.

    Science.gov (United States)

    Low, Hann; Mukhamedova, Nigora; Cui, Huanhuan L; McSharry, Brian P; Avdic, Selmir; Hoang, Anh; Ditiatkovski, Michael; Liu, Yingying; Fu, Ying; Meikle, Peter J; Blomberg, Martin; Polyzos, Konstantinos A; Miller, William E; Religa, Piotr; Bukrinsky, Michael; Soderberg-Naucler, Cecilia; Slobedman, Barry; Sviridov, Dmitri

    2016-06-28

    Cytomegalovirus (HCMV) contains cholesterol, but how HCMV interacts with host cholesterol metabolism is unknown. We found that, in human fibroblasts, HCMV infection increased the efflux of cellular cholesterol, despite reducing the abundance of ABCA1. Mechanistically, viral protein US28 was acting through CDC42, rearranging actin microfilaments, causing association of actin with lipid rafts, and leading to a dramatic change in the abundance and/or structure of lipid rafts. These changes displaced ABCA1 from the cell surface but created new binding sites for apolipoprotein A-I, resulting in enhanced cholesterol efflux. The changes also reduced the inflammatory response in macrophages. HCMV infection modified the host lipidome profile and expression of several genes and microRNAs involved in cholesterol metabolism. In mice, murine CMV infection elevated plasma triglycerides but did not affect the level and functionality of high-density lipoprotein. Thus, HCMV, through its protein US28, reorganizes lipid rafts and disturbs cell cholesterol metabolism.

  11. Pathways of cholesterol homeostasis in mouse retina responsive to dietary and pharmacologic treatments.

    Science.gov (United States)

    Zheng, Wenchao; Mast, Natalia; Saadane, Aicha; Pikuleva, Irina A

    2015-01-01

    Effects of serum cholesterol on cholesterol content in the retina are currently unknown. It is also unclear how cholesterol levels are controlled in the retina. High-cholesterol diet and oral administrations of simvastatin were used to modulate serum cholesterol in mice. These treatments only modestly affected cholesterol content in the retina and had no significant effect on retinal expression of the major cholesterol- and vision-related genes; the sterol-regulatory element binding protein pathway of transcriptional regulation does not seem to be operative in the retina under the experimental conditions used. Evidence is obtained that posttranslational mechanisms play a role in the control of retinal cholesterol. Retinal genes were only upregulated by oral administrations of TO901317 activating liver X receptors. Three of the upregulated genes could be of particular importance (apoD, Idol, and Rpe65) and have not yet been considered in the context of cholesterol homeostasis in the retina. Collectively, the data obtained identify specific features of retinal cholesterol maintenance and suggest additional therapies for age-related macular degeneration, a blinding disease characterized by cholesterol and lipid accumulations in chorioretinal tissues.

  12. Calpain-6 confers atherogenicity to macrophages by dysregulating pre-mRNA splicing

    Science.gov (United States)

    Tonami, Kazuo; Hata, Shoji; Aiuchi, Toshihiro; Lei, Xiao-Feng; Kim-Kaneyama, Joo-ri; Takeya, Motohiro; Itabe, Hiroyuki; Kurihara, Hiroki; Miyazaki, Akira

    2016-01-01

    Macrophages contribute to the development of atherosclerosis through pinocytotic deposition of native LDL–derived cholesterol in macrophages in the vascular wall. Inhibiting macrophage-mediated lipid deposition may have protective effects in atheroprone vasculature, and identifying mechanisms that potentiate this process may inform potential therapeutic interventions for atherosclerosis. Here, we report that dysregulation of exon junction complex–driven (EJC-driven) mRNA splicing confers hyperpinocytosis to macrophages during atherogenesis. Mechanistically, we determined that inflammatory cytokines induce an unconventional nonproteolytic calpain, calpain-6 (CAPN6), which associates with the essential EJC-loading factor CWC22 in the cytoplasm. This association disturbs the nuclear localization of CWC22, thereby suppressing the splicing of target genes, including those related to Rac1 signaling. CAPN6 deficiency in LDL receptor–deficient mice restored CWC22/EJC/Rac1 signaling, reduced pinocytotic deposition of native LDL in macrophages, and attenuated macrophage recruitment into the lesions, generating an atheroprotective phenotype in the aorta. In macrophages, the induction of CAPN6 in the atheroma interior limited macrophage movements, resulting in a decline in cell clearance from the lesions. Consistent with this finding, we observed that myeloid CAPN6 contributed to atherogenesis in a murine model of bone marrow transplantation. Furthermore, macrophages from advanced human atheromas exhibited increased CAPN6 induction and impaired CWC22 nuclear localization. Together, these results indicate that CAPN6 promotes atherogenicity in inflamed macrophages by disturbing CWC22/EJC systems. PMID:27525442

  13. [The real measurement of non-HDL-cholesterol: Atherogenic cholesterol].

    Science.gov (United States)

    Millán, Jesús; Hernández-Mijares, Antonio; Ascaso, Juan F; Blasco, Mariano; Brea, Angel; Díaz, Ángel; González-Santos, Pedro; Mantilla, Teresa; Pedro-Botet, Juan; Pintó, Xavier

    Lowe density lipoproteins (LDL) are the causal agent of cardiovascular diseases. In practice, we identify LDL with cholesterol transported in LDL (cLDL). So, cLDL has become the major target for cardiovascular prevention. Howewer, we have progressive evidences about the role of triglycerides rich lipoproteins, particularly those very low density lipoprotein (VLDL) in promotion and progression of atherosclerosis, that leads cholesterol in VLDL and its remanents as a potential therapeutic target. This feature is particularly important and of a great magnitude, in patients with hypertiglyceridemia. We can to considere, that the non-HDL cholesterol -cLDL+cVLDL+c-remmants+Lp(a)- is the real measurement of atherogenic cholesterol. In addition, non-HDL-cholesterol do not show any variations between postprandial states. In fact, non-HDL-cholesterol should be an excellent marker of atherogenic cholesterol, and an major therapeutic target in patients with atherogenic dyslipidaemia. According with different clinical trials and with the epidemiological and mendelian studies, in patients with high cardiovascular risk, optimal level of cLDL will be under 70mg/dl, and under 100 ng/dl for non-HDL-cholesterol; and in high risk patients, 100mg/dl and 130mg/dl, respectively. Copyright © 2016. Publicado por Elsevier España, S.L.U.

  14. Food combinations for cholesterol lowering.

    Science.gov (United States)

    Harland, Janice I

    2012-12-01

    Reducing elevated LDL-cholesterol is a key public health challenge. There is substantial evidence from randomised controlled trials (RCT) that a number of foods and food components can significantly reduce LDL-cholesterol. Data from RCT have been reviewed to determine whether effects are additive when two or more of these components are consumed together. Typically components, such as plant stanols and sterols, soya protein, β-glucans and tree nuts, when consumed individually at their target rate, reduce LDL-cholesterol by 3-9 %. Improved dietary fat quality, achieved by replacing SFA with unsaturated fat, reduces LDL-cholesterol and can increase HDL-cholesterol, further improving blood lipid profile. It appears that the effect of combining these interventions is largely additive; however, compliance with multiple changes may reduce over time. Food combinations used in ten 'portfolio diet' studies have been reviewed. In clinical efficacy studies of about 1 month where all foods were provided, LDL-cholesterol is reduced by 22-30 %, whereas in community-based studies of >6 months' duration, where dietary advice is the basis of the intervention, reduction in LDL-cholesterol is about 15 %. Inclusion of MUFA into 'portfolio diets' increases HDL-cholesterol, in addition to LDL-cholesterol effects. Compliance with some of these dietary changes can be achieved more easily compared with others. By careful food component selection, appropriate to the individual, the effect of including only two components in the diet with good compliance could be a sustainable 10 % reduction in LDL-cholesterol; this is sufficient to make a substantial impact on cholesterol management and reduce the need for pharmaceutical intervention.

  15. Chitosan oligosaccharides promote reverse cholesterol transport and expression of scavenger receptor BI and CYP7A1 in mice.

    Science.gov (United States)

    Zong, Chuanlong; Yu, Yang; Song, Guohua; Luo, Tian; Li, Luqin; Wang, Xinnong; Qin, Shucun

    2012-02-01

    Chitosan oligosaccharides (COS) are beneficial in improving plasma lipids and diminishing atherosclerotic risks. In this study, we examined the effects of COS on reverse cholesterol transport (RCT) in C57BL/6 mice. (3)H-cholesterol-laden macrophages were injected intraperitoneally into mice fed with various dosage of COS (250, 500, 1000 mg/kg mouse weight, respectively) or vehicle by gastric gavages. Plasma lipid level was determined and (3)H-cholesterol was traced in plasma, liver, bile and feces. The effects of COS on hepatic cholesterol 7 alpha-hydroxylase (CYP7A1) and scavenger receptor BI (SR-BI) expression were also investigated. COS administration led to a significant decrease in plasma total cholesterol and low-density lipoprotein (LDL) cholesterol and a significant increase in peritoneal macrophage-derived (3)H-cholesterol in liver and bile as well as in feces. Liver protein expressions of CYP7A1, SR-BI and LDL receptor (LDL-R) were improved in a dosage-dependent manner in COS-administered mice. Our findings provide the first in vivo demonstration of a positive role for COS in RCT pathway and hepatic CYP7A1 and SR-BI expression in mice. Additionally, the LDL cholesterol lowering effect might be relative to hepatic LDL-R expression stimulated by COS in mice.

  16. Dietary cholesterol promotes AOM-induced colorectal cancer through activating the NLRP3 inflammasome.

    Science.gov (United States)

    Du, Qianming; Wang, Qing; Fan, Huimin; Wang, Jianing; Liu, Xiuting; Wang, Hong; Wang, Yajing; Hu, Rong

    2016-04-01

    Prolonged ingestion of a cholesterol-enriched diet induces chronic, auto-inflammatory responses resulting in significant health problems including colorectal cancer. Inflammasomes are thought to mediate intestinal homeostasis, and their dysregulation contributes to inflammatory bowel diseases and colitis-associated cancer (CAC). However, in vitro and in vivo information regarding the inflammation-inducing and tumor-promoting effect of cholesterol is lacking. Here we show that the cholesterol promoted colon carcinogenesis in azoxymethane (AOM)-treated mice through activating the NLRP3 inflammasome. High cholesterol diet (HCD) significantly increased inflammatory responses and tumor burden. Cholesterol crystals, detected in the colon of mice fed with HCD, also promoted NLRP3 inflammasome activation in macrophages, as indicated by elevated expression of cleaved caspase-1, formation of NLRP3-ASC-caspase-1 complex assembly, and higher IL-1β secretion. Importantly, cholesterol was found to inhibit the activity of AMPKα in macrophages, leading to a significant production of mitochondrial ROS, which in turn activated the NLRP3 inflammasome. Moreover, crystal uptake and cathepsin B accounted for cholesterol crystal-induced inactivation of AMPKα. Finally, HCD-induced increase in IL-1β secretion, macrophage infiltration and tumor burden was diminished by the deletion of NLRP3 in AOM-treated mice. Taken together, our findings demonstrate that the pro-inflammatory and cancer-promoting effects of HCD are mediated by the activation of NLRP3 inflammasome. Our study extended our knowledge on how dietary choices can influence processes involved in chronic inflammatory disorders and colorectal cancer.

  17. HDL (Good), LDL (Bad) Cholesterol and Triglycerides

    Science.gov (United States)

    ... Thromboembolism Aortic Aneurysm More HDL (Good), LDL (Bad) Cholesterol and Triglycerides Updated:Jul 5,2017 Cholesterol isn’t just ... Your Cholesterol Score Explained What Are High Blood Cholesterol and Triglycerides? How Can I Improve My Cholesterol? | Spanish What ...

  18. What Do My Cholesterol Levels Mean?

    Science.gov (United States)

    ... results: total cholesterol, LDL (“bad”) and HDL (“good”) cholesterol, and triglycerides (blood fats). What should my total cholesterol level ... I Improve My Cholesterol? What Are High Blood Cholesterol and Triglycerides? What Is High Blood Pressure? How Can I ...

  19. Prevention and Treatment of High Cholesterol (Hyperlipidemia)

    Science.gov (United States)

    ... too many lipids (fats) in it, i.e., cholesterol and triglycerides. In hypercholesterolemia, there’s too much LDL (bad) cholesterol ... Your Cholesterol Score Explained What Are High Blood Cholesterol and Triglycerides? How Can I Improve My Cholesterol? | Spanish What ...

  20. Urotensin II promotes atherosclerosis in cholesterol-fed rabbits.

    Directory of Open Access Journals (Sweden)

    Yafeng Li

    Full Text Available Urotensin II (UII is a vasoactive peptide composed of 11 amino acids that has been implicated to contribute to the development of cardiovascular disease. The purpose of this study was to investigate whether UII affects the development of atherosclerosis in cholesterol-fed rabbits. UII was infused for 16 weeks through an osmotic mini-pump into male Japanese White rabbits fed on a high-cholesterol diet. Plasma lipids and body weight were measured every 4 weeks. Aortic atherosclerotic lesions along with cellular components, collagen fibers, matrix metalloproteinase-1 and -9 were examined. Moreover, vulnerability index of atherosclerotic plaques was evaluated. UII infusion significantly increased atherosclerotic lesions within the entire aorta by 21% over the control (P = 0.013. Atherosclerotic lesions were increased by 24% in the aortic arch (P = 0.005, 11% in the thoracic aorta (P = 0.054 and 18% in the abdominal aorta (P = 0.035. These increases occurred without changes in plasma levels of total cholesterol, low-density lipoprotein cholesterol, high-density lipoprotein cholesterol, triglycerides or body weight. Immunohistochemical staining revealed that macrophages and matrix metalloproteinase-9 were significantly enhanced by 2.2-fold and 1.6-fold in UII group. In vitro studies demonstrated that UII up-regulated the expression of vascular cell adhesion protein-1 and intercellular adhesion molecule-1 in human umbilical vein endothelial cells, which was inhibited by the UII receptor antagonist urantide. In conclusion, our results showed that UII promotes the development of atherosclerotic lesions and destabilizes atherosclerotic plaques in cholesterol-fed rabbits.

  1. Curcuma oil attenuates accelerated atherosclerosis and macrophage foam-cell formation by modulating genes involved in plaque stability, lipid homeostasis and inflammation.

    Science.gov (United States)

    Singh, Vishal; Rana, Minakshi; Jain, Manish; Singh, Niharika; Naqvi, Arshi; Malasoni, Richa; Dwivedi, Anil Kumar; Dikshit, Madhu; Barthwal, Manoj Kumar

    2015-01-14

    In the present study, the anti-atherosclerotic effect and the underlying mechanism of curcuma oil (C. oil), a lipophilic fraction from turmeric (Curcuma longa L.), was evaluated in a hamster model of accelerated atherosclerosis and in THP-1 macrophages. Male golden Syrian hamsters were subjected to partial carotid ligation (PCL) or FeCl3-induced arterial oxidative injury (Ox-injury) after 1 week of treatment with a high-cholesterol (HC) diet or HC diet plus C. oil (100 and 300 mg/kg, orally). Hamsters fed with the HC diet were analysed at 1, 3 and 5 weeks following carotid injury. The HC diet plus C. oil-fed group was analysed at 5 weeks. In hyperlipidaemic hamsters with PCL or Ox-injury, C. oil (300 mg/kg) reduced elevated plasma and aortic lipid levels, arterial macrophage accumulation, and stenosis when compared with those subjected to arterial injury alone. Similarly, elevated mRNA transcripts of matrix metalloproteinase-2 (MMP-2), MMP-9, cluster of differentiation 45 (CD45), TNF-α, interferon-γ (IFN-γ), IL-1β and IL-6 were reduced in atherosclerotic arteries, while those of transforming growth factor-β (TGF-β) and IL-10 were increased after the C. oil treatment (300 mg/kg). The treatment with C. oil prevented HC diet- and oxidised LDL (OxLDL)-induced lipid accumulation, decreased the mRNA expression of CD68 and CD36, and increased the mRNA expression of PPARα, LXRα, ABCA1 and ABCG1 in both hyperlipidaemic hamster-derived peritoneal and THP-1 macrophages. The administration of C. oil suppressed the mRNA expression of TNF-α, IL-1β, IL-6 and IFN-γ and increased the expression of TGF-β in peritoneal macrophages. In THP-1 macrophages, C. oil supplementation prevented OxLDL-induced production of TNF-α and IL-1β and increased the levels of TGF-β. The present study shows that C. oil attenuates arterial injury-induced accelerated atherosclerosis, inflammation and macrophage foam-cell formation.

  2. Cholesterol Granuloma in Odontogenic Cyst: An Enigmatic Lesion

    Science.gov (United States)

    Devi, Anju; Gupta, Shruti

    2016-01-01

    Cholesterol granuloma (CG) is the outcome of the foreign body type of response to the accumulation of cholesterol crystals and is frequently present in conjunction with chronic middle ear diseases. Recently, cases of CG in jaws have been reported, but still, very few cases have been found of CG in dental literature. This article presents three rare cases of CG in the wall of odontogenic cysts emphasizing on its possible role in expansion of the associated lesion and bone erosion. It also lays stress on the fact that more cases of CG should be reported so that its nature and pathogenesis in the oral cavity become more perceivable. PMID:28070428

  3. Complement activation by cholesterol crystals triggers a subsequent cytokine response

    DEFF Research Database (Denmark)

    Niyonzima, Nathalie; Halvorsen, Bente; Sporsheim, Bjørnar

    2017-01-01

    may under certain circumstances drive processes leading to adverse inflammation. One example is cholesterol crystals (CC) that accumulate in the vessel wall during early phases of atherogenesis and represent an important endogenous danger signal promoting inflammation. CC is recognized by the lectin...... of inflammation processes before downstream release of cytokines including IL-1β. Another therapeutic candidate can be broad-acting 2-hydroxypropyl-β-cyclodextrin, a compound that targets several mechanisms such as cholesterol efflux, complement gene expression, and the NLRP3 pathway. In summary, emerging...

  4. Phytosterol ester processing in the small intestine: impact on cholesterol availability for absorption and chylomicron cholesterol incorporation in healthy humans.

    Science.gov (United States)

    Amiot, Marie Josèphe; Knol, Diny; Cardinault, Nicolas; Nowicki, Marion; Bott, Romain; Antona, Claudine; Borel, Patrick; Bernard, Jean-Paul; Duchateau, Guus; Lairon, Denis

    2011-06-01

    Phytosterols (plant sterols and stanols) can lower intestinal cholesterol absorption, but the complex dynamics of the lipid digestion process in the presence of phytosterol esters (PEs) are not fully understood. We performed a clinical experiment in intubated healthy subjects to study the time course of changes in the distribution of all lipid moieties present in duodenal phases during 4 h of digestion of meals with 3.2 g PE (PE meal) or without (control meal) PE. In vitro experiments under simulated gastrointestinal conditions were also performed. The addition of PE did not alter triglyceride (TG) hydrolysis in the duodenum or subsequent chylomicron TG occurrence in the circulation. In contrast, cholesterol accumulation in the duodenum aqueous phase was markedly reduced in the presence of PE (-32%, P < 0.10). In vitro experiments confirmed that PE reduces cholesterol transfer into the aqueous phase. The addition of PE resulted in a markedly reduced presence of meal-derived hepta-deuterated cholesterol in the circulation, i.e., in chylomicrons (-43%, PE meal vs. control; P < 0.0001) and plasma (-54%, PE meal vs. control; P < 0.0001). The present data show that addition of PE to a meal does not alter TG hydrolysis but displaces cholesterol from the intestinal aqueous phase and lowers chylomicron cholesterol occurrence in humans.

  5. Lysosomal acid lipase: At the crossroads of normal and atherogenic cholesterol metabolism

    Directory of Open Access Journals (Sweden)

    Joshua A Dubland

    2015-02-01

    Full Text Available Unregulated cellular uptake of apolipoprotein B-containing lipoproteins in the arterial intima leads to the formation of foam cells in atherosclerosis. Lysosomal acid lipase (LAL plays a crucial role in both lipoprotein lipid catabolism and excess lipid accumulation as it is the primary enzyme that hydrolyzes cholesteryl esters derived from both low density lipoprotein (LDL and modified forms of LDL. Evidence suggests that as atherosclerosis progresses, accumulation of excess free cholesterol in lysosomes leads to impairment of LAL activity, resulting in accumulation of cholesteryl esters in the lysosome as well as the cytosol in foam cells. Impaired metabolism and release of cholesterol from lysosomes can lead to downstream defects in ATP-binding cassette transporter A1 regulation, needed to offload excess cholesterol from plaque foam cells. This review focuses on the role LAL plays in normal cholesterol metabolism and how the associated changes in its enzymatic activity may ultimately contribute to atherosclerosis progression.

  6. Top Five Lifestyle Changes to Reduce Cholesterol

    Science.gov (United States)

    Top 5 lifestyle changes to improve your cholesterol Lifestyle changes can help reduce cholesterol, keep you off cholesterol-lowering medications or enhance the effect of your medications. Here are five lifestyle ...

  7. Understand Your Risk for High Cholesterol

    Science.gov (United States)

    ... Aortic Aneurysm More Understand Your Risk for High Cholesterol Updated:Apr 1,2016 LDL (bad) cholesterol is ... content was last reviewed on 04/21/2014. Cholesterol Guidelines: Putting the pieces together Myth vs. Truth – ...

  8. Estimations of cholesterol, triglycerides and fractionation of ...

    African Journals Online (AJOL)

    Estimations of cholesterol, triglycerides and fractionation of lipoproteins in serum samples of some Nigerian female subjects. ... low density lipoprotein-cholesterol (LDL-C) and very low density lipoprotein-cholesterol (VLDL-C) ... Article Metrics.

  9. Cholesterol metabolism and colon cancer.

    Science.gov (United States)

    Broitman, S A; Cerda, S; Wilkinson, J

    1993-01-01

    While epidemiologic and concordant experimental data indicate a direct relationship between dietary fat (and presumably caloric) intake and the development of colon cancer, the effect of dietary cholesterol on this disease is still not clear. However, there appears to be a developing literature concerning an inverse relationship between serum and plasma cholesterol levels, and the risk for colon cancer. Findings that low serum cholesterol levels are apparent as early as ten years prior to the detection of colon cancer implies that sub clinical disease is probably not involved initially in this process. The possibility of low serum cholesterol as a bio-marker was considered in epidemiologic studies which focused upon obese men with lower than normal serum cholesterol levels who were found to be at increased risk to colon cancer. While the relationship between low serum cholesterol and colonic or intestinal cholesterol metabolism is presently not understood, current genetic studies provide a promising though as yet unexplored potential association. Alterations which occur during the developmental progression of colonic cancer include changes in chromosome 5, which also carries two genes vital to the biosynthesis and regulation of systemic and cellular cholesterol metabolism, 3-hydroxy-3-methylglutaryl coenzyme A synthase, and 3-hydroxy-3-methylglutaryl coenzyme A reductase (HMGCoA R). Regulation of cholesterol metabolism in intestinal cells in vivo and in vitro varies from that seen in normal fibroblasts or hepatocytes in terms of exogenous sources of cholesterol and how these sources regulate internal synthesis. Colonic cancer cells have been used to assess small bowel enterocyte cholesterol metabolism, which has been possible because of their ability to differentiate in culture, however information regarding true colonic enterocyte cholesterol metabolism is relatively scarce. Colonic cancer cells have been shown to possess a diminished or nonexistent ability to use

  10. Intracellular transport of low density lipoprotein-derived cholesterol is defective in Niemann-Pick type C fibroblasts

    Energy Technology Data Exchange (ETDEWEB)

    Liscum, L.; Ruggiero, R.M.; Faust, J.R.

    1989-05-01

    Niemann-Pick disease type C (NPC) is characterized by substantial intracellular accumulation of unesterified cholesterol. The accumulation of unesterified cholesterol in NPC fibroblasts cultured with low density lipoprotein (LDL) appears to result from the inability of LDL to stimulate cholesterol esterification in addition to impaired LDL-mediated downregulation of LDL receptor activity and cellular cholesterol synthesis. Although a defect in cholesterol transport in NPC cells has been inferred from previous studies, no experiments have been reported that measure the intracellular movement of LDL-cholesterol specifically. We have used four approaches to assess intracellular cholesterol transport in normal and NPC cells and have determined the following: (a) mevinolin-inhibited NPC cells are defective in using LDL-cholesterol for growth. However, exogenously added mevalonate restores cell growth equally in normal and NPC cells; (b) the transport of LDL-derived (3H)cholesterol to the plasma membrane is slower in NPC cells, while the rate of appearance of (3H)acetate-derived, endogenously synthesized (3H)cholesterol at the plasma membrane is the same for normal and NPC cells; (c) in NPC cells, LDL-derived (3H)cholesterol accumulates in lysosomes to higher levels than normal, resulting in defective movement to other cell membranes; and (d) incubation of cells with LDL causes an increase in cholesterol content of NPC lysosomes that is threefold greater than that observed in normal lysosomes. Our results indicate that a cholesterol transport defect exists in NPC that is specific for LDL-derived cholesterol.

  11. Lecithin:Cholesterol Acyltransferase (LCAT) Deficiency Promotes Differentiation of Satellite Cells to Brown Adipocytes in a Cholesterol-dependent Manner.

    Science.gov (United States)

    Nesan, Dinushan; Tavallaee, Ghazaleh; Koh, Deborah; Bashiri, Amir; Abdin, Rawand; Ng, Dominic S

    2015-12-18

    Our laboratory previously reported that lecithin:cholesterol acyltransferase (LCAT) and LDL receptor double knock-out mice (Ldlr(-/-)xLcat(-/-) or DKO) spontaneously develop functioning ectopic brown adipose tissue (BAT) in skeletal muscle, putatively contributing to protection from the diet-induced obesity phenotype. Here we further investigated their developmental origin and the mechanistic role of LCAT deficiency. Gene profiling of skeletal muscle in DKO newborns and adults revealed a classical lineage. Primary quiescent satellite cells (SC) from chow-fed DKO mice, not in Ldlr(-/-)xLcat(+/+) single-knock-out (SKO) or C57BL/6 wild type, were found to (i) express exclusively classical BAT-selective genes, (ii) be primed to express key functional BAT genes, and (iii) exhibit markedly increased ex vivo adipogenic differentiation into brown adipocytes. This gene priming effect was abrogated upon feeding the mice a 2% high cholesterol diet in association with accumulation of excess intracellular cholesterol. Ex vivo cholesterol loading of chow-fed DKO SC recapitulated the effect, indicating that cellular cholesterol is a key regulator of SC-to-BAT differentiation. Comparing adipogenicity of Ldlr(+/+)xLcat(-/-) (LCAT-KO) SC with DKO SC identified a role for LCAT deficiency in priming SC to express BAT genes. Additionally, we found that reduced cellular cholesterol is important for adipogenic differentiation, evidenced by increased induction of adipogenesis in cholesterol-depleted SC from both LCAT-KO and SKO mice. Taken together, we conclude that ectopic BAT in DKO mice is classical in origin, and its development begins in utero. We further showed complementary roles of LCAT deficiency and cellular cholesterol reduction in the SC-to-BAT adipogenesis. © 2015 by The American Society for Biochemistry and Molecular Biology, Inc.

  12. Catabolism and biotechnological applications of cholesterol degrading bacteria.

    Science.gov (United States)

    García, J L; Uhía, I; Galán, B

    2012-11-01

    Cholesterol is a steroid commonly found in nature with a great relevance in biology, medicine and chemistry, playing an essential role as a structural component of animal cell membranes. The ubiquity of cholesterol in the environment has made it a reference biomarker for environmental pollution analysis and a common carbon source for different microorganisms, some of them being important pathogens such as Mycobacterium tuberculosis. This work revises the accumulated biochemical and genetic knowledge on the bacterial pathways that degrade or transform this molecule, given that the characterization of cholesterol metabolism would contribute not only to understand its role in tuberculosis but also to develop new biotechnological processes that use this and other related molecules as starting or target materials.

  13. Inclusion of Almonds in a Cholesterol-Lowering Diet Improves Plasma HDL Subspecies and Cholesterol Efflux to Serum in Normal-Weight Individuals with Elevated LDL Cholesterol.

    Science.gov (United States)

    Berryman, Claire E; Fleming, Jennifer A; Kris-Etherton, Penny M

    2017-08-01

    Background: Almonds may increase circulating HDL cholesterol when substituted for a high-carbohydrate snack in an isocaloric diet, yet little is known about the effects on HDL biology and function.Objective: The objective was to determine whether incorporating 43 g almonds/d in a cholesterol-lowering diet would improve HDL subspecies and function, which were secondary study outcomes.Methods: In a randomized, 2-period, crossover, controlled-feeding study, a diet with 43 g almonds/d (percentage of total energy: 51% carbohydrate, 16% protein, and 32% total and 8% saturated fat) was compared with a similar diet with an isocaloric muffin substitution (58% carbohydrate, 15% protein, and 26% total and 8% saturated fat) in men and women with elevated LDL cholesterol. Plasma HDL subspecies and cholesterol efflux from J774 macrophages to human serum were measured at baseline and after each diet period. Diet effects were examined in all participants (n = 48) and in normal-weight (body mass index: HDL [mean ± SEM: 26.7 ± 1.5 compared with 24.3 ± 1.3 mg apolipoprotein A-I (apoA-I)/dL; P = 0.001]. In normal-weight participants, the almond diet, relative to the control diet, increased α-1 HDL (33.7 ± 3.2 compared with 28.4 ± 2.6 mg apoA-I/dL), the α-1 to pre-β-1 ratio [geometric mean (95% CI): 4.3 (3.3, 5.7) compared with 3.1 (2.4, 4.0)], and non-ATP-binding cassette transporter A1 cholesterol efflux (8.3% ± 0.4% compared with 7.8% ± 0.3%) and decreased pre-β-2 (3.8 ± 0.4 compared with 4.6 ± 0.4 mg apoA-I/dL) and α-3 (23.5 ± 0.9 compared with 26.9 ± 1.1 mg apoA-I/dL) HDL (P HDL subpopulation distribution and improve cholesterol efflux in normal-weight individuals with elevated LDL cholesterol. This trial was registered at clinicaltrials.gov as NCT01101230. © 2017 American Society for Nutrition.

  14. Quercetin-3-O-glucuronide induces ABCA1 expression by LXRα activation in murine macrophages

    Energy Technology Data Exchange (ETDEWEB)

    Ohara, Kazuaki, E-mail: Kazuaki_Ohara@kirin.co.jp [Research Laboratories for Health Science and Food Technologies, Kirin Company Limited, 1-13-5 Fukuura, Kanazawa-ku, Yokohama 236-0004 (Japan); Wakabayashi, Hideyuki [Laboratory for New Product Development, Kirin Beverage Company Limited, 1-17-1 Namamugi, Tsurumi-ku, Yokohama 230-8628 (Japan); Taniguchi, Yoshimasa [Research Laboratories for Health Science and Food Technologies, Kirin Company Limited, 1-13-5 Fukuura, Kanazawa-ku, Yokohama 236-0004 (Japan); Shindo, Kazutoshi [Department of Food and Nutrition, Japan Women’s University, 2-8-1 Mejirodai, Bunkyo-ku, Tokyo 112-8681 (Japan); Yajima, Hiroaki [Research Laboratories for Health Science and Food Technologies, Kirin Company Limited, 1-13-5 Fukuura, Kanazawa-ku, Yokohama 236-0004 (Japan); Yoshida, Aruto [Central Laboratories for Key Technologies, Kirin Company Limited, 1-13-5 Fukuura, Kanazawa-ku, Yokohama 236-0004 (Japan)

    2013-11-29

    Highlights: •The major circulating quercetin metabolite (Q3GA) activated LXRα. •Q3GA induced ABCA1 via LXRα activation in macrophages. •Nelumbo nucifera leaf extracts contained quercetin glycosides. •N. nucifera leaf extract feeding elevated HDLC in mice. -- Abstract: Reverse cholesterol transport (RCT) removes excess cholesterol from macrophages to prevent atherosclerosis. ATP-binding cassette, subfamily A, member 1 (ABCA1) is a crucial cholesterol transporter involved in RCT to produce high density lipoprotein-cholesterol (HDLC), and is transcriptionally regulated by liver X receptor alpha (LXRα), a nuclear receptor. Quercetin is a widely distributed flavonoid in edible plants which prevented atherosclerosis in an animal model. We found that quercetin-3-O-glucuronide (Q3GA), a major quercetin metabolite after absorption from the digestive tract, enhanced ABCA1 expression, in vitro, via LXRα in macrophages. In addition, leaf extracts of a traditional Asian edible plant, Nelumbo nucifera (NNE), which contained abundant amounts of quercetin glycosides, significantly elevated plasma HDLC in mice. We are the first to present experimental evidence that Q3GA induced ABCA1 in macrophages, and to provide an alternative explanation to previous studies on arteriosclerosis prevention by quercetin.

  15. Consumption of Japanese Yam Improves Lipid Metabolism in High-Cholesterol Diet-Fed Rats.

    Science.gov (United States)

    Kusano, Yuri; Tsujihara, Nobuko; Masui, Hironori; Kozai, Hana; Takeuchi, Wakako

    2016-01-01

    We investigated the effects of dietary Japanese yam (Dioscorea japonica Thunb.) on lipid metabolism. Male Wistar rats (6 wk old) were fed a high-cholesterol diet for 6 wk and then supplemented with 26% of Japanese yam or 0.5% of its constituent diosgenin for a further 4 wk of high-cholesterol feeding (C6-J4 and C6-D4 groups, respectively). In the C6-J4 group, body weight gains significantly decreased, but skeletal muscle fiber sizes in quadriceps significantly increased compared with the other groups. Furthermore, Japanese yam supplementation resulted in the reduction of triglyceride contents in their liver, quadriceps, and intra-abdominal visceral fat. Diosgenin supplementation resulted in an increase in the numbers of skeletal muscle fibers and decrease in the fat accumulations in liver and of the lipid contents in quadriceps. Although quadriceps cholesterol contents decreased concomitantly with increased serum HDL-cholesterol in both the groups, fecal bile acid, fecal cholesterol contents, and fecal weight were higher in the C6-J4 group than in the C6-D4 group. Meanwhile, we demonstrated that Japanese yam inhibited micellar cholesterol solubility in vitro in a concentration-dependent manner. These results suggest that Japanese yam is more effective than diosgenin in reducing fat accumulation and improving cholesterol metabolism during chronic consumption of a high-cholesterol diet.

  16. Cholesterol testing on a smartphone.

    Science.gov (United States)

    Oncescu, Vlad; Mancuso, Matthew; Erickson, David

    2014-02-21

    Home self-diagnostic tools for blood cholesterol monitoring have been around for over a decade but their widespread adoption has been limited by the relatively high cost of acquiring a quantitative test-strip reader, complicated procedure for operating the device, and inability to easily store and process results. To address this we have developed a smartphone accessory and software application that allows for the quantification of cholesterol levels in blood. Through a series of human trials we demonstrate that the system can accurately quantify total cholesterol levels in blood within 60 s by imaging standard test strips. In addition, we demonstrate how our accessory is optimized to improve measurement sensitivity and reproducibility across different individual smartphones. With the widespread adoption of smartphones and increasingly sophisticated image processing technology, accessories such as the one presented here will allow cholesterol monitoring to become more accurate and widespread, greatly improving preventive care for cardiovascular disease.

  17. Americans' Cholesterol Levels Keep Falling

    Science.gov (United States)

    ... and 2013-2014, the CDC reported. Dr. David Friedman is chief of heart failure services at Long ... for cholesterol treatment, all seem to be working," Friedman said. The study was published online Nov. 30 ...

  18. Formation of cholesterol bilayer domains precedes formation of cholesterol crystals in cholesterol/dimyristoylphosphatidylcholine membranes: EPR and DSC studies.

    Science.gov (United States)

    Mainali, Laxman; Raguz, Marija; Subczynski, Witold K

    2013-08-01

    Saturation-recovery EPR along with DSC were used to determine the cholesterol content at which pure cholesterol bilayer domains (CBDs) and cholesterol crystals begin to form in dimyristoylphosphatidylcholine (DMPC) membranes. To preserve compositional homogeneity throughout the membrane suspension, lipid multilamellar dispersions were prepared using a rapid solvent exchange method. The cholesterol content increased from 0 to 75 mol %. With spin-labeled cholesterol analogues, it was shown that the CBDs begin to form at ~50 mol % cholesterol. It was confirmed by DSC that the cholesterol solubility threshold for DMPC membranes is detected at ~66 mol % cholesterol. At levels above this cholesterol content, monohydrate cholesterol crystals start to form. The major finding is that the formation of CBDs precedes formation of cholesterol crystals. The region of the phase diagram for cholesterol contents between 50 and 66 mol % is described as a structured one-phase region in which CBDs have to be supported by the surrounding DMPC bilayer saturated with cholesterol. Thus, the phase boundary located at 66 mol % cholesterol separates the structured one-phase region (liquid-ordered phase of DMPC with CBDs) from the two-phase region where the structured liquid-ordered phase of DMPC coexists with cholesterol crystals. It is likely that CBDs are precursors of monohydrate cholesterol crystals.

  19. [Macrophages in asthma].

    Science.gov (United States)

    Medina Avalos, M A; Orea Solano, M

    1997-01-01

    Every time they exist more demonstrations of the paper than performs the line monocytes-macrophage in the patogenesis of the bronchial asthma. The mononuclear phagocytes cells, as the alveolar macrophages, also they can be activated during allergic methods. The monocytes macrophages are possible efficient inductors of the inflammation; this due to the fact that they can secrete inflammatory mediators, between those which are counted the pre-forming granules of peptides, metabolites of oxidation activation, activator of platelets activator and metabolites of the arachidonic acid. The identification of IL-1 in the liquidate of the bronchial ablution of sick asthmatic, as well as the identification of IL-1 in the I bronchioalveolar washing of places of allergens cutaneous prick, supports the activation concept mononuclear of phagocytic cells in allergic sufferings.

  20. Macrophages and Iron Metabolism.

    Science.gov (United States)

    Soares, Miguel P; Hamza, Iqbal

    2016-03-15

    Iron is a transition metal that due to its inherent ability to exchange electrons with a variety of molecules is essential to support life. In mammals, iron exists mostly in the form of heme, enclosed within an organic protoporphyrin ring and functioning primarily as a prosthetic group in proteins. Paradoxically, free iron also has the potential to become cytotoxic when electron exchange with oxygen is unrestricted and catalyzes the production of reactive oxygen species. These biological properties demand that iron metabolism is tightly regulated such that iron is available for core biological functions while preventing its cytotoxic effects. Macrophages play a central role in establishing this delicate balance. Here, we review the impact of macrophages on heme-iron metabolism and, reciprocally, how heme-iron modulates macrophage function.

  1. Cholesterol Worships a New Idol

    Institute of Scientific and Technical Information of China (English)

    Ira G. Schulman

    2009-01-01

    The growing worldwide epidemic of cardiovascular disease suggests that new therapeutic strategies are needed to complement statins in the lowering of cholesterol levels. In a recent paper in Science, Tontonoz and colleagues have identified Idol as a protein that can control cholesterol levels by regulating the stability of the low-density lipoprotein receptor; inhibiting the activity of Idol could provide novel approaches for the treatment of cardiovascular disease.

  2. A relation between high-density-lipoprotein cholesterol and bile cholesterol saturation.

    OpenAIRE

    Thornton, J R; Heaton, K W; Macfarlane, D.G.

    1981-01-01

    The association of cholesterol gall stones with coronary artery disease is controversial. To investigate this possible relation at the biochemical level, bile cholesterol saturation and the plasma concentrations of triglycerides, total cholesterol, and high-density-lipoprotein cholesterol (HDL cholesterol) were measured in 25 healthy, middle-aged women. Bile cholesterol saturation index was negatively correlated with HDL cholesterol. It was positively correlated with plasma triglycerides and ...

  3. Cholesterol and benign prostate disease.

    Science.gov (United States)

    Freeman, Michael R; Solomon, Keith R

    2011-01-01

    The origins of benign prostatic diseases, such as benign prostatic hyperplasia (BPH) and chronic prostatitis/chronic pelvic pain syndrome (CP/CPPS), are poorly understood. Patients suffering from benign prostatic symptoms report a substantially reduced quality of life, and the relationship between benign prostate conditions and prostate cancer is uncertain. Epidemiologic data for BPH and CP/CPPS are limited, however an apparent association between BPH symptoms and cardiovascular disease (CVD) has been consistently reported. The prostate synthesizes and stores large amounts of cholesterol and prostate tissues may be particularly sensitive to perturbations in cholesterol metabolism. Hypercholesterolemia, a major risk factor for CVD, is also a risk factor for BPH. Animal model and clinical trial findings suggest that agents that inhibit cholesterol absorption from the intestine, such as the class of compounds known as polyene macrolides, can reduce prostate gland size and improve lower urinary tract symptoms (LUTS). Observational studies indicate that cholesterol-lowering drugs reduce the risk of aggressive prostate cancer, while prostate cancer cell growth and survival pathways depend in part on cholesterol-sensitive biochemical mechanisms. Here we review the evidence that cholesterol metabolism plays a role in the incidence of benign prostate disease and we highlight possible therapeutic approaches based on this concept.

  4. Steroidal Triterpenes of Cholesterol Synthesis

    Directory of Open Access Journals (Sweden)

    Damjana Rozman

    2013-04-01

    Full Text Available Cholesterol synthesis is a ubiquitous and housekeeping metabolic pathway that leads to cholesterol, an essential structural component of mammalian cell membranes, required for proper membrane permeability and fluidity. The last part of the pathway involves steroidal triterpenes with cholestane ring structures. It starts by conversion of acyclic squalene into lanosterol, the first sterol intermediate of the pathway, followed by production of 20 structurally very similar steroidal triterpene molecules in over 11 complex enzyme reactions. Due to the structural similarities of sterol intermediates and the broad substrate specificity of the enzymes involved (especially sterol-Δ24-reductase; DHCR24 the exact sequence of the reactions between lanosterol and cholesterol remains undefined. This article reviews all hitherto known structures of post-squalene steroidal triterpenes of cholesterol synthesis, their biological roles and the enzymes responsible for their synthesis. Furthermore, it summarises kinetic parameters of enzymes (Vmax and Km and sterol intermediate concentrations from various tissues. Due to the complexity of the post-squalene cholesterol synthesis pathway, future studies will require a comprehensive meta-analysis of the pathway to elucidate the exact reaction sequence in different tissues, physiological or disease conditions. A major reason for the standstill of detailed late cholesterol synthesis research was the lack of several steroidal triterpene standards. We aid to this efforts by summarizing commercial and laboratory standards, referring also to chemical syntheses of meiosis-activating sterols.

  5. Constitutive hippocampal cholesterol loss underlies poor cognition in old rodents.

    Science.gov (United States)

    Martin, Mauricio G; Ahmed, Tariq; Korovaichuk, Alejandra; Venero, Cesar; Menchón, Silvia A; Salas, Isabel; Munck, Sebastian; Herreras, Oscar; Balschun, Detlef; Dotti, Carlos G

    2014-05-30

    Cognitive decline is one of the many characteristics of aging. Reduced long-term potentiation (LTP) and long-term depression (LTD) are thought to be responsible for this decline, although the precise mechanisms underlying LTP and LTD dampening in the old remain unclear. We previously showed that aging is accompanied by the loss of cholesterol from the hippocampus, which leads to PI3K/Akt phosphorylation. Given that Akt de-phosphorylation is required for glutamate receptor internalization and LTD, we hypothesized that the decrease in cholesterol in neuronal membranes may contribute to the deficits in LTD typical of aging. Here, we show that cholesterol loss triggers p-Akt accumulation, which in turn perturbs the normal cellular and molecular responses induced by LTD, such as impaired AMPA receptor internalization and its reduced lateral diffusion. Electrophysiology recordings in brain slices of old mice and in anesthetized elderly rats demonstrate that the reduced hippocampal LTD associated with age can be rescued by cholesterol perfusion. Accordingly, cholesterol replenishment in aging animals improves hippocampal-dependent learning and memory in the water maze test.

  6. Cholesterol reducing agents inhibit assembly of type I parainfluenza viruses.

    Science.gov (United States)

    Bajimaya, Shringkhala; Hayashi, Tsuyoshi; Frankl, Tünde; Bryk, Peter; Ward, Brian; Takimoto, Toru

    2017-01-15

    Many enveloped RNA viruses utilize lipid rafts for the assembly of progeny virions, but the role of cholesterol, a major component of rafts, on paramyxovirus budding and virion formation is controversial. In this study, we analyzed the effects of FDA-approved cholesterol-reducing agents, gemfibrozil and lovastatin, on raft formation and assembly of human parainfluenza virus type 1 (hPIV1) and Sendai virus (SeV). Treatment of the human airway epithelial A549 cells with the agents, especially when combined, significantly decreased production of infectious hPIV1 and SeV. Mechanistic analysis indicated that depletion of cellular cholesterol reduced cell surface accumulation of envelope glycoproteins and association of viral matrix and nucleocapsids with raft membrane, which resulted in impaired virus budding and release from the cells. These results indicate that cellular cholesterol is required for assembly and formation of type 1 parainfluenza viruses and suggest that cholesterol could be an attractive target for antiviral agents against hPIV1. Copyright © 2016 Elsevier Inc. All rights reserved.

  7. Disruption of Lipid Rafts Interferes with the Interaction of Toxoplasma gondii with Macrophages and Epithelial Cells

    Science.gov (United States)

    Cruz, Karla Dias; Cruz, Thayana Araújo; Veras de Moraes, Gabriela; Paredes-Santos, Tatiana Christina; Attias, Marcia; de Souza, Wanderley

    2014-01-01

    The intracellular parasite Toxoplasma gondii can penetrate any warm-blooded animal cell. Conserved molecular assemblies of host cell plasma membranes should be involved in the parasite-host cell recognition. Lipid rafts are well-conserved membrane microdomains that contain high concentrations of cholesterol, sphingolipids, glycosylphosphatidylinositol, GPI-anchored proteins, and dually acylated proteins such as members of the Src family of tyrosine kinases. Disturbing lipid rafts of mouse peritoneal macrophages and epithelial cells of the lineage LLC-MK2 with methyl-beta cyclodextrin (MβCD) and filipin, which interfere with cholesterol or lidocaine, significantly inhibited internalization of T. gondii in both cell types, although adhesion remained unaffected in macrophages and decreased only in LLC-MK2 cells. Scanning and transmission electron microscopy confirmed these observations. Results are discussed in terms of the original role of macrophages as professional phagocytes versus the LLC-MK2 cell lineage originated from kidney epithelial cells. PMID:24734239

  8. Cell elasticity determines macrophage function.

    Directory of Open Access Journals (Sweden)

    Naimish R Patel

    Full Text Available Macrophages serve to maintain organ homeostasis in response to challenges from injury, inflammation, malignancy, particulate exposure, or infection. Until now, receptor ligation has been understood as being the central mechanism that regulates macrophage function. Using macrophages of different origins and species, we report that macrophage elasticity is a major determinant of innate macrophage function. Macrophage elasticity is modulated not only by classical biologic activators such as LPS and IFN-γ, but to an equal extent by substrate rigidity and substrate stretch. Macrophage elasticity is dependent upon actin polymerization and small rhoGTPase activation, but functional effects of elasticity are not predicted by examination of gene expression profiles alone. Taken together, these data demonstrate an unanticipated role for cell elasticity as a common pathway by which mechanical and biologic factors determine macrophage function.

  9. Sida rhomboidea.Roxb aqueous extract down-regulates in vivo expression of vascular cell adhesion molecules in atherogenic rats and inhibits in vitro macrophage differentiation and foam cell formation.

    Science.gov (United States)

    Thounaojam, Menaka C; Jadeja, Ravirajsinh N; Salunke, Sunita P; Devkar, Ranjitsinh V; Ramachandran, A V

    2012-10-01

    The present study evaluates efficacy of Sida rhomboidea.Roxb (SR) leaves extract in ameliorating experimental atherosclerosis using in vitro and in vivo experimental models. Atherogenic (ATH) diet fed rats recorded significant increment in the serum total cholesterol (TC), triglycerides (TG), low-density lipoprotein (LDL), very LDL (VLDL), autoantibody against oxidized LDL (Ox-LDL), markers of LDL oxidation and decrement in high-density lipoprotein (HDL) along with increment in aortic TC and TG. The ex vivo LDL oxidation assay revealed an increased susceptibility of LDL isolated from ATH rats to undergo copper mediated oxidation. These set of changes were minimized by simultaneous co-supplementation of SR extract to ATH diet fed rats. Histopathology of aorta and immunolocalization studies recorded pronounced atheromatous plaque formation, vascular calcification, significant elastin derangements and higher expression of macrophage surface marker (F4/80), vascular cell adhesion molecule-1 (VCAM-1) and p-selectin in ATH rats. Whereas, ATH+SR rats depicted minimal evidence of atheromatous plaque formation, calcium deposition, distortion/defragmentation of elastin and accumulation of macrophages along with lowered expression of VCAM-1 and P-selectin compared to ATH rats. Further, monocyte to macrophage differentiation and in vitro foam cell formation were significantly attenuated in presence of SR extract. In conclusion, SR extract has the potency of controlling experimental atherosclerosis and can be used as promising herbal supplement in combating atherosclerosis.

  10. Cholesterol-induced conformational changes in the sterol-sensing domain of the Scap protein suggest feedback mechanism to control cholesterol synthesis.

    Science.gov (United States)

    Gao, Yansong; Zhou, Yulian; Goldstein, Joseph L; Brown, Michael S; Radhakrishnan, Arun

    2017-05-26

    Scap is a polytopic protein of endoplasmic reticulum (ER) membranes that transports sterol regulatory element-binding proteins to the Golgi complex for proteolytic activation. Cholesterol accumulation in ER membranes prevents Scap transport and decreases cholesterol synthesis. Previously, we provided evidence that cholesterol inhibition is initiated when cholesterol binds to loop 1 of Scap, which projects into the ER lumen. Within cells, this binding causes loop 1 to dissociate from loop 7, another luminal Scap loop. However, we have been unable to demonstrate this dissociation when we added cholesterol to isolated complexes of loops 1 and 7. We therefore speculated that the dissociation requires a conformational change in the intervening polytopic sequence separating loops 1 and 7. Here we demonstrate such a change using a protease protection assay in sealed membrane vesicles. In the absence of cholesterol, trypsin or proteinase K cleaved cytosolic loop 4, generating a protected fragment that we visualized with a monoclonal antibody against loop 1. When cholesterol was added to these membranes, cleavage in loop 4 was abolished. Because loop 4 is part of the so-called sterol-sensing domain separating loops 1 and 7, these results support the hypothesis that cholesterol binding to loop 1 alters the conformation of the sterol-sensing domain. They also suggest that this conformational change helps transmit the cholesterol signal from loop 1 to loop 7, thereby allowing separation of the loops and facilitating the feedback inhibition of cholesterol synthesis. These insights suggest a new structural model for cholesterol-mediated regulation of Scap activity. © 2017 by The American Society for Biochemistry and Molecular Biology, Inc.

  11. Novel inhibitors of cholesterol degradation in Mycobacterium tuberculosis reveal how the bacterium's metabolism is constrained by the intracellular environment.

    Directory of Open Access Journals (Sweden)

    Brian C VanderVen

    2015-02-01

    Full Text Available Mycobacterium tuberculosis (Mtb relies on a specialized set of metabolic pathways to support growth in macrophages. By conducting an extensive, unbiased chemical screen to identify small molecules that inhibit Mtb metabolism within macrophages, we identified a significant number of novel compounds that limit Mtb growth in macrophages and in medium containing cholesterol as the principle carbon source. Based on this observation, we developed a chemical-rescue strategy to identify compounds that target metabolic enzymes involved in cholesterol metabolism. This approach identified two compounds that inhibit the HsaAB enzyme complex, which is required for complete degradation of the cholesterol A/B rings. The strategy also identified an inhibitor of PrpC, the 2-methylcitrate synthase, which is required for assimilation of cholesterol-derived propionyl-CoA into the TCA cycle. These chemical probes represent new classes of inhibitors with novel modes of action, and target metabolic pathways required to support growth of Mtb in its host cell. The screen also revealed a structurally-diverse set of compounds that target additional stage(s of cholesterol utilization. Mutants resistant to this class of compounds are defective in the bacterial adenylate cyclase Rv1625/Cya. These data implicate cyclic-AMP (cAMP in regulating cholesterol utilization in Mtb, and are consistent with published reports indicating that propionate metabolism is regulated by cAMP levels. Intriguingly, reversal of the cholesterol-dependent growth inhibition caused by this subset of compounds could be achieved by supplementing the media with acetate, but not with glucose, indicating that Mtb is subject to a unique form of metabolic constraint induced by the presence of cholesterol.

  12. Niacin to Boost Your HDL "Good" Cholesterol

    Science.gov (United States)

    Niacin can boost 'good' cholesterol Niacin is a B vitamin that may raise your HDL ("good") cholesterol. But side effects might outweigh benefits for most ... been used to increase high-density lipoprotein (HDL) cholesterol — the "good" cholesterol that helps remove low-density ...

  13. Amperometric determination of serum total cholesterol with nanoparticles of cholesterol esterase and cholesterol oxidase.

    Science.gov (United States)

    Aggarwal, V; Malik, J; Prashant, A; Jaiwal, P K; Pundir, C S

    2016-05-01

    We describe the preparation of glutaraldehyde cross-linked and functionalized cholesterol esterase nanoparticles (ChENPs) and cholesterol oxidase nanoparticles (ChOxNPs) aggregates and their co-immobilization onto Au electrode for improved amperometric determination of serum total cholesterol. Transmission electron microscope (TEM) images of ChENPs and ChOxNPs showed their spherical shape and average size of 35.40 and 56.97 nm, respectively. Scanning electron microscope (SEM) studies of Au electrode confirmed the co-immobilization of enzyme nanoparticles (ENPs). The biosensor exhibited optimal response at pH 5.5 and 40°C within 5 s when polarized at +0.25 V versus Ag/AgCl. The working/linear range of the biosensor was 10-700 mg/dl for cholesterol. The sensor showed high sensitivity and measured total cholesterol as low as 0.1 mg/dl. The biosensor was evaluated and employed for total cholesterol determination in sera of apparently healthy and diseased persons. The analytical recovery of added cholesterol was 90%, whereas the within-batch and between-batch coefficients of variation (CVs) were less than 2% and less than 3%. There was a good correlation (r = 0.99) between serum cholesterol values as measured by the standard enzymic colorimetric method and the current method. The initial activity of ENPs/working electrode was reduced by 50% during its regular use (200 times) over a period of 60 days when stored dry at 4°C.

  14. Up-regulation of cholesterol associated genes as novel resistance mechanism in glioblastoma cells in response to archazolid B

    Energy Technology Data Exchange (ETDEWEB)

    Hamm, Rebecca; Zeino, Maen [Institute of Pharmacy and Biochemistry, Department of Pharmaceutical Biology, Johannes Gutenberg University, Staudinger Weg 5, 55128 Mainz (Germany); Frewert, Simon [Helmholtz Institute for Pharmaceutical Research Saarland, Helmholtz Centre for Infection Research and Department of Pharmaceutical Biotechnology, Saarland University, Saarbrücken (Germany); Efferth, Thomas, E-mail: efferth@uni-mainz.de [Institute of Pharmacy and Biochemistry, Department of Pharmaceutical Biology, Johannes Gutenberg University, Staudinger Weg 5, 55128 Mainz (Germany)

    2014-11-15

    Treatment of glioblastoma multiforme (GBM), the most common and aggressive lethal brain tumor, represents a great challenge. Despite decades of research, the survival prognosis of GBM patients is unfavorable and more effective therapeutics are sorely required. Archazolid B, a potent vacuolar H{sup +}-ATPase inhibitor influencing cellular pH values, is a promising new compound exerting cytotoxicity in the nanomolar range on wild-type U87MG glioblastoma cells and U87MG.∆EGFR cells transfected with a mutant epidermal growth factor receptor (EGFR) gene. Gene expression profiling using microarray technology showed that archazolid B caused drastic disturbances in cholesterol homeostasis. Cholesterol, a main component of cellular membranes, is known to be essential for GBM growth and cells bearing EGFRvIII mutation are highly dependent on exogenous cholesterol. Archazolid B caused excessive accumulation of free cholesterol within intracellular compartments thus depleting cellular cholesterol and leading to up-regulation of SREBP targeted genes, including LDLR and HMGCR, the key enzyme of cholesterol biosynthesis. This cholesterol response is considered to be a novel resistance mechanism induced by archazolid B. We surmise that re-elevation of cholesterol levels in archazolid B treated cells may be mediated by newly synthesized cholesterol, since the drug leads to endosomal/lysosomal malfunction and cholesterol accumulation.

  15. Selective and specific macrophage ablation is detrimental to wound healing in mice.

    Science.gov (United States)

    Mirza, Rita; DiPietro, Luisa A; Koh, Timothy J

    2009-12-01

    Macrophages are thought to play important roles during wound healing, but definition of these roles has been hampered by our technical inability to specifically eliminate macrophages during wound repair. The purpose of this study was to test the hypothesis that specific depletion of macrophages after excisional skin wounding would detrimentally affect healing by reducing the production of growth factors important in the repair process. We used transgenic mice that express the human diphtheria toxin (DT) receptor under the control of the CD11b promoter (DTR mice) to specifically ablate macrophages during wound healing. Mice without the transgene are relatively insensitive to DT, and administration of DT to wild-type mice does not alter macrophage or other inflammatory cell accumulation after injury and does not influence wound healing. In contrast, treatment of DTR mice with DT prevented macrophage accumulation in healing wounds but did not affect the accumulation of neutrophils or monocytes. Such macrophage depletion resulted in delayed re-epithelialization, reduced collagen deposition, impaired angiogenesis, and decreased cell proliferation in the healing wounds. These adverse changes were associated with increased levels of tumor necrosis factor-alpha and reduced levels of transforming growth factor-beta1 and vascular endothelial growth factor in the wound. In summary, macrophages seem to promote both wound closure and dermal healing, in part by regulating the cytokine environment of the healing wound.

  16. The usefulness of total cholesterol and high density lipoprotein ...

    African Journals Online (AJOL)

    The usefulness of total cholesterol and high density lipoprotein - cholesterol ratio in ... cholesterol and/or highdensity lipoprotein cholesterol/total cholesterol ratios in the interpretation of lipid profile result in clinical practice. ... Article Metrics.

  17. Changes in Macrophage Gene Expression Associated with Leishmania (Viannia braziliensis Infection.

    Directory of Open Access Journals (Sweden)

    Clemencia Ovalle-Bracho

    Full Text Available Different Leishmania species cause distinct clinical manifestations of the infectious disease leishmaniasis. It is fundamentally important to understand the mechanisms governing the interaction between Leishmania and its host cell. Little is known about this interaction between Leishmania (Viannia braziliensis and human macrophages. In this study, we aimed to identify differential gene expression between non-infected and L. (V braziliensis-infected U937-derived macrophages. We deployed a whole human transcriptome microarray analysis using 72 hours post-infection samples and compared those samples with their non-infected counterparts. We found that 218 genes were differentially expressed between infected and non-infected macrophages. A total of 71.6% of these genes were down-regulated in the infected macrophages. Functional enrichment analyses identified the steroid and sterol/cholesterol biosynthetic processes between regulatory networks down-regulated in infected macrophages. RT-qPCR further confirmed this down-regulation in genes belonging to these pathways. These findings contrast with those from studies involving other Leishmania species at earlier infection stages, where gene up-regulation for this metabolic pathway has been reported. Sterol biosynthesis could be an important biological process associated with the expression profile of macrophages infected by L. (V. braziliensis. Differential transcriptional results suggest a negative regulation of the genetic regulatory network involved in cholesterol biosynthesis.

  18. Major role of adipocyte prostaglandin E2 in lipolysis-induced macrophage recruitment[S

    Science.gov (United States)

    Hu, Xiaoqian; Cifarelli, Vincenza; Sun, Shishuo; Kuda, Ondrej; Abumrad, Nada A.; Su, Xiong

    2016-01-01

    Obesity induces accumulation of adipose tissue macrophages (ATMs), which contribute to both local and systemic inflammation and modulate insulin sensitivity. Adipocyte lipolysis during fasting and weight loss also leads to ATM accumulation, but without proinflammatory activation suggesting distinct mechanisms of ATM recruitment. We examined the possibility that specific lipid mediators with anti-inflammatory properties are released from adipocytes undergoing lipolysis to induce macrophage migration. In the present study, we showed that conditioned medium (CM) from adipocytes treated with forskolin to stimulate lipolysis can induce migration of RAW 264.7 macrophages. In addition to FFAs, lipolytic stimulation increased release of prostaglandin E2 (PGE2) and prostaglandin D2 (PGD2), reflecting cytosolic phospholipase A2 α activation and enhanced cyclooxygenase (COX) 2 expression. Reconstituted medium with the anti-inflammatory PGE2 potently induced macrophage migration while different FFAs and PGD2 had modest effects. The ability of CM to induce macrophage migration was abolished by treating adipocytes with the COX2 inhibitor sc236 or by treating macrophages with the prostaglandin E receptor 4 antagonist AH23848. In fasted mice, macrophage accumulation in adipose tissue coincided with increases of PGE2 levels and COX1 expression. Collectively, our data show that adipocyte-originated PGE2 with inflammation suppressive properties plays a significant role in mediating ATM accumulation during lipolysis. PMID:26912395

  19. Cholesterol granuloma of the lateral ventricle. Case report.

    Science.gov (United States)

    Grossi, Peter M; Ellis, Michael J; Cummings, Thomas J; Gray, Linda L; Fukushima, Takanori; Sampson, John H

    2008-02-01

    Cholesterol granulomas (CGs) are benign lesions resulting from an inflammatory reaction to cholesterol and hemosiderin. These masses most often arise within the temporal bone or nasal sinuses; intracerebral CGs are extremely rare. In this report the authors present an unusual case of a CG arising within the lateral ventricle. The patient presented with transient hemiparesis and numbness. Computed tomography and magnetic resonance imaging demonstrated a cystic partially enhancing midline mass within the right lateral ventricle, expanding the ventricle and displacing the septum pellucidum. The patient underwent an interhemispheric, transcallosal resection of the lesion. Microscopic examination revealed a granulomatous inflammatory lesion containing cholesterol clefts, macrophages, and hemosiderin. Embedded within the granulomatous response were foci of tiny cystlike structures lined by nonciliated flattened cuboidal epithelium, consistent with the diagnosis of CG. To the authors' knowledge this is the first reported case of CG presenting as an intraventricular mass. The origin of this lesion is unclear, but it may relate to prior traumatic brain injury. The authors describe the presentation, imaging findings, histopathological characteristics, and surgical treatment of this rare lesion and related pathological entities.

  20. Cholesterol metabolism in cholestatic liver disease and liver transplantation:From molecular mechanisms to clinical implications

    Institute of Scientific and Technical Information of China (English)

    Katriina; Nemes; Fredrik; ?berg; Helena; Gylling; Helena; Isoniemi

    2016-01-01

    The aim of this review is to enlighten the critical roles that the liver plays in cholesterol metabolism. Liver transplantation can serve as gene therapy or a source of gene transmission in certain conditions that affect cholesterol metabolism, such as low-density-lipoprotein(LDL) receptor gene mutations that are associated with familial hypercholesterolemia. On the other hand, cholestatic liver disease often alters cholesterol metabolism. Cholestasis can lead to formation of lipoprotein X(Lp-X), which is frequently mistaken for LDL on routine clinical tests. In contrast to LDL, Lp-X is non-atherogenic, and failure to differentiate between the two can interfere with cardiovascular risk assessment, potentially leading to prescription of futile lipid-lowering therapy. Statins do not effectively lower Lp-X levels, and cholestasis may lead to accumulation of toxic levels of statins. Moreover, severe cholestasis results in poor micellar formation, which reduces cholesterol absorption, potentially impairing the cholesterol-lowering effect of ezetimibe. Apolipoprotein B-100 measurement can help distinguish between atherogenic and non-atherogenic hypercholesterolemia. Furthermore, routine serum cholesterol measurements alone cannot reflect cholesterol absorption and synthesis. Measurements of serum non-cholesterol sterol biomarkers- such as cholesterol precursor sterols, plant sterols, and cholestanol- may help with the comprehensive assessment of cholesterol metabolism. An adequate cholesterol supply is essential for liver-regenerative capacity. Low preoperative and perioperative serum cholesterol levels seem to predict mortality in liver cirrhosis and after liver transplantation. Thus, accurate lipid profile evaluation is highly important in liver disease and after liver transplantation.

  1. Effects of a disrupted blood-brain barrier on cholesterol homeostasis in the brain.

    Science.gov (United States)

    Saeed, Ahmed A; Genové, Guillem; Li, Tian; Lütjohann, Dieter; Olin, Maria; Mast, Natalia; Pikuleva, Irina A; Crick, Peter; Wang, Yuqin; Griffiths, William; Betsholtz, Christer; Björkhem, Ingemar

    2014-08-22

    The presence of the blood-brain barrier (BBB) is critical for cholesterol metabolism in the brain, preventing uptake of lipoprotein-bound cholesterol from the circulation. The metabolic consequences of a leaking BBB for cholesterol metabolism have not been studied previously. Here we used a pericyte-deficient mouse model, Pdgfb(ret/ret), shown to have increased permeability of the BBB to a range of low-molecular mass and high-molecular mass tracers. There was a significant accumulation of plant sterols in the brains of the Pdgfb(ret/ret) mice. By dietary treatment with 0.3% deuterium-labeled cholesterol, we could demonstrate a significant flux of cholesterol from the circulation into the brains of the mutant mice roughly corresponding to about half of the measured turnover of cholesterol in the brain. We expected the cholesterol flux into the brain to cause a down-regulation of cholesterol synthesis. Instead, cholesterol synthesis was increased by about 60%. The levels of 24(S)-hydroxycholesterol (24S-OHC) were significantly reduced in the brains of the pericyte-deficient mice but increased in the circulation. After treatment with 1% cholesterol in diet, the difference in cholesterol synthesis between mutants and controls disappeared. The findings are consistent with increased leakage of 24S-OHC from the brain into the circulation in the pericyte-deficient mice. This oxysterol is an efficient suppressor of cholesterol synthesis, and the results are consistent with a regulatory role of 24S-OHC in the brain. To our knowledge, this is the first demonstration that a defective BBB may lead to increased flux of a lipophilic compound out from the brain. The relevance of the findings for the human situation is discussed.

  2. An Essential Role of Hrs/Vps27 in Endosomal Cholesterol Trafficking

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    Ximing Du

    2012-01-01

    Full Text Available The endosomal sorting complex required for transport (ESCRT plays a crucial role in the degradation of ubiquitinated endosomal membrane proteins. Here, we report that Hrs, a key protein of the ESCRT-0 complex, is required for the transport of low-density lipoprotein-derived cholesterol from endosomes to the endoplasmic reticulum. This function of Hrs in cholesterol transport is distinct from its previously defined role in lysosomal sorting and downregulation of membrane receptors via the ESCRT pathway. In line with this, knocking down other ESCRT proteins does not cause prominent endosomal cholesterol accumulation. Importantly, the localization and biochemical properties of key cholesterol-sorting proteins, NPC1 and NPC2, appear to be unchanged upon Hrs knockdown. Our data identify Hrs as a regulator of endosomal cholesterol trafficking and provide additional insights into the budding of intralumenal vesicles.

  3. 2-heptyl-formononetin increases cholesterol and induces hepatic steatosis in mice

    DEFF Research Database (Denmark)

    Andersen, Charlotte; Schjoldager, Janne Gram; Tortzen, Christian

    2013-01-01

    Consumption of isoflavones may prevent adiposity, hepatic steatosis, and dyslipidaemia. However, studies in the area are few and primarily with genistein. This study investigated the effects of formononetin and its synthetic analogue, 2-heptyl-formononetin (C7F), on lipid and cholesterol metabolism...... in C57BL/6J mice. The mice were fed a cholesterol-enriched diet for five weeks to induce hypercholesterolemia and were then fed either the cholesterol-enriched diet or the cholesterol-enriched diet-supplemented formononetin or C7F for three weeks. Body weight and composition, glucose homeostasis......, and plasma lipids were compared. In another experiment, mice were fed the above diets for five weeks, and hepatic triglyceride accumulation and gene expression and histology of adipose tissue and liver were examined. Supplementation with C7F increased plasma HDL-cholesterol thereby increasing the plasma...

  4. Quantification and localization of M2 macrophages in human kidneys with acute tubular injury

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    Palmer MB

    2014-11-01

    Full Text Available Matthew B Palmer,1 Alfred A Vichot,2 Lloyd G Cantley,2 Gilbert W Moeckel1 1Department of Pathology, Yale University School of Medicine, New Haven, CT, USA; 2Department of Medicine, Yale University School of Medicine, New Haven, CT, USA Abstract: This study addresses for the first time the question whether there is significant macrophage population in human kidney sections from patients with acute tubular injury (ATI. We examined therefore the interstitial macrophage population in human kidney tissue with biopsy-proven diagnosis of ATI, minimal change disease (MCD, and MCD with ATI. Kidney biopsies from patients with the above diagnoses were stained with antibodies directed against CD68 (general macrophage marker, CD163 (M2 marker, and HLA-DR (M1 marker and their respective electron microscopy samples were evaluated for the presence of interstitial macrophages. Our study shows that patients with ATI have significantly increased numbers of interstitial CD68+ macrophages, with an increase in both HLA-DR+ M1 macrophages and CD163+ M2 macrophages as compared to patients with MCD alone. Approximately 75% of macrophages were M2 (CD163+ whereas only 25% were M1 (HLA-DR+. M2 macrophages, which are believed to be critical for wound healing, were found to localize close to the tubular basement membrane of injured proximal tubule cells. Ultra structural examination showed close adherence of macrophages to the basement membrane of injured tubular epithelial cells. We conclude that macrophages accumulate around injured tubules following ATI and exhibit predominantly an M2 phenotype. We further speculate that macrophage-mediated repair may involve physical contact between the M2 macrophage and the injured tubular epithelial cell. Keywords: macrophages, acute kidney injury, CD163, HLA-DR, CD68, electron microscopy

  5. Transcriptional Regulation and Macrophage Differentiation.

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    Hume, David A; Summers, Kim M; Rehli, Michael

    2016-06-01

    Monocytes and macrophages are professional phagocytes that occupy specific niches in every tissue of the body. Their survival, proliferation, and differentiation are controlled by signals from the macrophage colony-stimulating factor receptor (CSF-1R) and its two ligands, CSF-1 and interleukin-34. In this review, we address the developmental and transcriptional relationships between hematopoietic progenitor cells, blood monocytes, and tissue macrophages as well as the distinctions from dendritic cells. A huge repertoire of receptors allows monocytes, tissue-resident macrophages, or pathology-associated macrophages to adapt to specific microenvironments. These processes create a broad spectrum of macrophages with different functions and individual effector capacities. The production of large transcriptomic data sets in mouse, human, and other species provides new insights into the mechanisms that underlie macrophage functional plasticity.

  6. The macrophages in rheumatic diseases

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    Laria A

    2016-02-01

    Full Text Available Antonella Laria, Alfredomaria Lurati , Mariagrazia Marrazza , Daniela Mazzocchi, Katia Angela Re, Magda Scarpellini Rheumatology Unit, Fornaroli Hospital, Magenta, Italy Abstract: Macrophages belong to the innate immune system giving us protection against pathogens. However it is known that they are also involved in rheumatic diseases. Activated macrophages have two different phenotypes related to different stimuli: M1 (classically activated and M2 (alternatively activated. M1 macrophages release high levels of pro-inflammatory cytokines, reactive nitrogen and oxygen intermediates killing microorganisms and tumor cells; while M2 macrophages are involved in resolution of inflammation through phagocytosis of apoptotic neutrophils, reduced production of pro-inflammatory cytokines, and increased synthesis of mediators important in tissue remodeling, angiogenesis, and wound repair. The role of macrophages in the different rheumatic diseases is different according to their M1/M2 macrophages phenotype. Keywords: macrophage, rheumatic diseases

  7. Augmented atherogenesis in LDL receptor deficient mice lacking both macrophage ABCA1 and ApoE.

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    Bart Lammers

    Full Text Available AIM: ABCA1 protects against atherosclerosis by facilitating cholesterol efflux from macrophage foam cells in the arterial wall to extracellular apolipoprotein (apo A-I. In contrast to apoA-I, apoE is secreted by macrophages and can, like apoA-I, induce ABCA1-mediated cholesterol efflux. Yet, the combined effect of macrophage ABCA1 and apoE on lesion development is unexplored. METHODS AND RESULTS: LDL receptor knockout (KO mice were transplanted with bone marrow from ABCA1/apoE double KO (dKO mice, their respective single KO's, and wild-type (WT controls and were challenged with a high-fat/high-cholesterol diet for 9 weeks. In vitro cholesterol efflux experiments showed no differences between ABCA1 KO and dKO macrophages. The serum non-HDL/HDL ratio in dKO transplanted mice was 1.7-fold and 2.4-fold (p<0.01 increased compared to WT and ABCA1 KO transplanted mice, respectively. The atherosclerotic lesion area in dKO transplanted animals (650±94×10(3 µm(2, however, was 1.9-fold (p<0.01 and 1.6-fold (p<0.01 increased compared to single knockouts (ABCA1 KO: 341±20×10(3 µm(2; apoE KO: 402±78×10(3 µm(2, respectively and 3.1-fold increased (p<0.001 compared to WT (211±20×10(3 µm(2. When normalized for serum cholesterol exposure, macrophage ABCA1 and apoE independently protected against atherosclerotic lesion development (p<0.001. Moreover, hepatic expression levels of TNFα and IL-6 were highly induced in dKO transplanted animals (3.0-fold; p<0.05, and 4.3-fold; p<0.001, respectively. In agreement, serum IL-6 levels were also enhanced in ABCA1 KO transplanted mice (p<0.05 and even further enhanced in dKO transplanted animals (3.1-fold as compared to ABCA1 KO transplanted animals; p<0.05. CONCLUSIONS: Combined deletion of macrophage ABCA1 and apoE results in a defect in cholesterol efflux and, compared to ABCA1 KO transplanted mice, elevated serum total cholesterol levels. Importantly, these mice also suffer from enhanced systemic and hepatic

  8. Akt inhibition promotes ABCA1-mediated cholesterol efflux to ApoA-I through suppressing mTORC1.

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    Fumin Dong

    Full Text Available ATP-binding cassette transporter A1 (ABCA1 plays an essential role in mediating cholesterol efflux to apolipoprotein A-I (apoA-I, a major housekeeping mechanism for cellular cholesterol homeostasis. After initial engagement with ABCA1, apoA-I directly interacts with the plasma membrane to acquire cholesterol. This apoA-I lipidation process is also known to require cellular signaling processes, presumably to support cholesterol trafficking to the plasma membrane. We report here that one of major signaling pathways in mammalian cells, Akt, is also involved. In several cell models that express ABCA1 including macrophages, pancreatic beta cells and hepatocytes, inhibition of Akt increases cholesterol efflux to apoA-I. Importantly, Akt inhibition has little effect on cells expressing non-functional mutant of ABCA1, implicating a specific role of Akt in ABCA1 function. Furthermore, we provide evidence that mTORC1, a major downstream target of Akt, is also a negative regulator of cholesterol efflux. In cells where mTORC1 is constitutively activated due to tuberous sclerosis complex 2 deletion, cholesterol efflux to apoA-I is no longer sensitive to Akt activity. This suggests that Akt suppresses cholesterol efflux through mTORC1 activation. Indeed, inhibition of mTORC1 by rapamycin or Torin-1 promotes cholesterol efflux. On the other hand, autophagy, one of the major pathways of cholesterol trafficking, is increased upon Akt inhibition. Furthermore, Akt inhibition disrupts lipid rafts, which is known to promote cholesterol efflux to apoA-I. We therefore conclude that Akt, through its downstream targets, mTORC1 and hence autophagy, negatively regulates cholesterol efflux to apoA-I.

  9. Cholesterol confusion and statin controversy

    Institute of Scientific and Technical Information of China (English)

    Robert; Du; Broff; Michel; de; Lorgeril

    2015-01-01

    The role of blood cholesterol levels in coronary heart disease(CHD) and the true effect of cholesterollowering statin drugs are debatable. In particular,whether statins actually decrease cardiac mortality and increase life expectancy is controversial. Concurrently,the Mediterranean diet model has been shown to prolong life and reduce the risk of diabetes,cancer,and CHD. We herein review current data related to both statins and the Mediterranean diet. We conclude that the expectation that CHD could be prevented or eliminated by simply reducing cholesterol appears unfounded. On the contrary,we should acknowledge the inconsistencies of the cholesterol theory and recognize the proven benefits of a healthy lifestyle incorporating a Mediterranean diet to prevent CHD.

  10. Seladin-1/DHCR24 protects neuroblastoma cells against Aβ toxicity by increasing membrane cholesterol content

    Science.gov (United States)

    Cecchi, C; Rosati, F; Pensalfini, A; Formigli, L; Nosi, D; Liguri, G; Dichiara, F; Morello, M; Danza, G; Pieraccini, G; Peri, A; Serio, M; Stefani, M

    2008-01-01

    The role of brain cholesterol in Alzheimer's disease (AD) is currently a matter of debate. Experimental evidence suggests that reducing circulating and brain cholesterol protects against AD, however recent data indicate that low membrane cholesterol results in neurode-generation and that the cholesterol synthesis catalyst seladin-1 is down-regulated in AD-affected brain regions. We previously reported a significant correlation between resistance to amyloid toxicity and content of membrane cholesterol in differing cultured cell types. Here we provide evidence that Aβ42 pre-fibrillar aggregates accumulate more slowly and in reduced amount at the plasma membrane of human SH-SY5Y neuroblastoma cells overexpressing seladin-1 or treated with PEG-cholesterol than at the membrane of control cells. The accumulation was significantly increased in cholesterol-depleted cells following treatment with the specific seladin-1 inhibitor 5,22E-cholestadien-3-ol or with methyl-β-cyclodextrin. The resistance to amyloid toxicity and the early cytosolic Ca2+ rise following exposure to Aβ42 aggregates were increased and prevented, respectively, by increasing membrane cholesterol whereas the opposite effects were found in cholesterol-depleted cells. These results suggest that seladin-1-dependent cholesterol synthesis reduces membrane-aggregate interaction and cell damage associated to amyloid-induced imbalance of cytosolic Ca2+. Our findings extend recently reported data indicating that seladin-1 overexpression directly enhances the resistance to Aβ toxicity featuring seladin-1/DHCR 24 as a possible new susceptibility gene for sporadic AD. PMID:18194465

  11. Tenascin-c renders a proangiogenic phenotype in macrophage via annexin II.

    Science.gov (United States)

    Wang, Zhiyang; Wei, Qi; Han, Liang; Cao, Keqing; Lan, Tianfeng; Xu, Zhenjie; Wang, Yingjuan; Gao, Yuan; Xue, Jing; Shan, Fei; Feng, Jun; Xie, Xin

    2017-08-30

    Tenascin-c is an extracellular matrix glycoprotein, the expression of which relates to the progression of atherosclerosis, myocardial infarction and heart failure. Annexin II acts as a cell surface receptor of tenascin-c. This study aimed to delineate the role of tenascin-c and annexin II in macrophages presented in atherosclerotic plaque. Animal models with atherosclerotic lesions were established using ApoE-KO mice fed with high-cholesterol diet. The expression of tenascin-c and annexin II in atherosclerotic lesions was determined by qRT-PCR, Western blot and immunohistochemistry analysis. Raw 264.7 macrophages and human primary macrophages were exposed to 5, 10 and 15 μg/ml tenascin-c for 12 hrs. Cell migration as well as the proangiogenic ability of macrophages was examined. Additionally, annexin II expression was delineated in raw 264.7 macrophages under normal condition (20% O2 ) for 12 hrs or hypoxic condition (1% O2 ) for 6-12 hrs. The expression of tenascin-c and annexin II was markedly augmented in lesion aorta. Tenascin-c positively regulated macrophage migration, which was dependent on the expression of annexin II in macrophages. VEGF release from macrophages and endothelial tube induction by macrophage were boosted by tenascin-c and attenuated by annexin II blocking. Furthermore, tenascin-c activated Akt/NF-κB and ERK signalling through annexin II. Lastly, hypoxia conditioning remarkably facilitates annexin II expression in macrophages through hypoxia-inducible factor (HIF)-1α but not HIF-2α. In conclusion, tenascin-c promoted macrophage migration and VEGF expression through annexin II, the expression of which was modulated by HIF-1α. © 2017 The Authors. Journal of Cellular and Molecular Medicine published by John Wiley & Sons Ltd and Foundation for Cellular and Molecular Medicine.

  12. The liver-selective thyromimetic T-0681 influences reverse cholesterol transport and atherosclerosis development in mice.

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    Ivan Tancevski

    Full Text Available Liver-selective thyromimetics have been reported to efficiently reduce plasma cholesterol through the hepatic induction of both, the low-density lipoprotein receptor (LDLr and the high-density lipoprotein (HDL receptor; the scavenger receptor class B type I (SR-BI. Here, we investigated the effect of the thyromimetic T-0681 on reverse cholesterol transport (RCT and atherosclerosis, and studied the underlying mechanisms using different mouse models, including mice lacking LDLr, SR-BI, and apoE, as well as CETP transgenic mice.T-0681 treatment promoted bile acid production and biliary sterol secretion consistently in the majority of the studied mouse models, which was associated with a marked reduction of plasma cholesterol. Using an assay of macrophage RCT in mice, we found T-0681 to significantly increase fecal excretion of macrophage-derived neutral and acidic sterols. No positive effect on RCT was found in CETP transgenic mice, most likely due to the observed decrease in plasma CETP mass. Studies in SR-BI KO and LDLr KO mice suggested hepatic LDLr to be necessary for the action of T-0681 on lipid metabolism, as the compound did not have any influence on plasma cholesterol levels in mice lacking this receptor. Finally, prolonged treatment with T-0681 reduced the development of atherosclerosis by 60% in apoE KOs on Western type diet. In contrast, at an earlier time-point T-0681 slightly increased small fatty streak lesions, in part due to an impaired macrophage cholesterol efflux capacity, when compared to controls.The present results show that liver-selective thyromimetics can promote RCT and that such compounds may protect from atherosclerosis partly through induction of bile acid metabolism and biliary sterol secretion. On-going clinical trials will show whether selective thyromimetics do prevent atherosclerosis also in humans.

  13. Free cholesterol induces higher β-sheet content in Aβ peptide oligomers by aromatic interaction with Phe19.

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    Xiaolin Zhou

    Full Text Available Accumulating experimental evidence support an enhancing effect of free cholesterol on amyloid-beta (Aβ aggregation. To probe the mechanisms of cholesterol-mediated Aβ aggregation, we applied all-atom molecular dynamic simulations on Aβ42 peptides in presence of free cholesterol. Several control systems were also designed to examine the specificity of cholesterol-residue interactions, including mutation on aromatic residue, substitution of cholesterol with sphingomyelin (SM and DPPC bilayer, and a mixing SM and cholesterol. Each system was performed 4 independent simulations, with a total time of 560 ns. It was found that cholesterol increased β-sheet formation by 4 folds, but the Phe19→Ser mutation on Aβ42 peptide totally eliminated cholesterol's effect. A stable contact was recognized between the steroid group of cholesterol and the Benzyl group of Phe19. Interestingly, our simulation revealed a regular 1 ns time interval between the establishment of cholesterol-phenylalanine contact and consequent β-sheet formation, suggesting an important role of steroid-benzyl interaction in cholesterol-mediated aggregation. The presence of SM slightly increased β-sheet formation, but the mixture of cholesterol and SM had a strong induction effect. Also, the measurement of Phe19-lipid distance indicates that aromatic side chains of peptides prone to bind to cholesterol on the surface of the mixed micelle. In the DPPC system, polar chains were attracted to the surface of membrane, yielding moderate increase of β-sheet formation. These results shed light on the mechanism of cholesterol-mediated fibrillogenesis, and help to differentiate the effects of cholesterol and other lipids on β-sheet formation process.

  14. ROCK-Isoform-Specific Polarization of Macrophages Associated with Age-Related Macular Degeneration

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    Souska Zandi

    2015-02-01

    Full Text Available Age is a major risk factor in age-related macular degeneration (AMD, but the underlying cause is unknown. We find increased Rho-associated kinase (ROCK signaling and M2 characteristics in eyes of aged mice, revealing immune changes in aging. ROCK isoforms determine macrophage polarization into M1 and M2 subtypes. M2-like macrophages accumulated in AMD, but not in normal eyes, suggesting that these macrophages may be linked to macular degeneration. M2 macrophages injected into the mouse eye exacerbated choroidal neovascular lesions, while M1 macrophages ameliorated them, supporting a causal role for macrophage subtypes in AMD. Selective ROCK2 inhibition with a small molecule decreased M2-like macrophages and choroidal neovascularization. ROCK2 inhibition upregulated M1 markers without affecting macrophage recruitment, underlining the plasticity of these macrophages. These results reveal age-induced innate immune imbalance as underlying AMD pathogenesis. Targeting macrophage plasticity opens up new possibilities for more effective AMD treatment.

  15. Intravascular ultrasound predictors of CD163 positive macrophage infiltration.

    Science.gov (United States)

    Sato, Takao; Kameyama, Tomoki; Ueno, Hiroshi; Inoue, Hiroshi

    2014-06-01

    The present study aimed to determine characteristics of macrophage accumulation and predictors of CD163 positive macrophages by ultrasonic tissue characterization. Intraplaque hemorrhage is associated with plaque instability and induces macrophage accumulation with a scavenger receptor, CD163. These CD163 positive macrophages have anti-atherogenic property. In 50 patients with acute coronary syndrome, lumen, vessel and plaque area, and plaque components (% fibrous, % fibro fatty, % dense calcium, and % necrotic core) of the culprit lesion were determined by virtual histology (VH) intravascular ultrasound (IVUS). Remodeling index (RI) was also determined. Atherothrombotic debris of the culprit lesion was collected during percutaneous coronary intervention using a distal protection device. CD163 positive macrophages and glycophorin A (a protein specific to erythrocytes) were determined immunohistochemically. Percentage of CD163 positive macrophages to the whole cells (% CD163) correlated positively with lumen, vessel and plaque area, and RI. Further, % CD163 had significant positive correlation with % necrotic core and negative correlation with % dense calcium. Immunopositive areas of glycophorin A (% glycophorin A), expressed as the ratio of positively stained areas per total tissue, had a significant positive correlation with % CD163. On multivariate analysis, % necrotic core, % dense calcium, and RI were independent determinants of % CD163. Positive remodeling and large necrotic core without calcification on VH-IVUS were likely to indicate coronary intraplaque hemorrhage with CD163 positive macrophages infiltration. © 2014, Wiley Periodicals, Inc.

  16. Modulation of macrophage antitumor potential by apoptotic lymphoma cells.

    Science.gov (United States)

    Voss, Jorine J L P; Ford, Catriona A; Petrova, Sofia; Melville, Lynsey; Paterson, Margaret; Pound, John D; Holland, Pam; Giotti, Bruno; Freeman, Tom C; Gregory, Christopher D

    2017-06-01

    In aggressive non-Hodgkin's lymphoma (NHL), constitutive apoptosis of a proportion of the tumor cell population can promote net tumor growth. This is associated with the accumulation of tumor-associated macrophages (TAMs) that clear apoptotic cells and exhibit pro-oncogenic transcriptional activation profiles characteristic of reparatory, anti-inflammatory and angiogenic programs. Here we consider further the activation status of these TAMs. We compare their transcriptomic profile with that of a range of other macrophage types from various tissues noting especially their expression of classically activated (IFN-γ and LPS) gene clusters - typically antitumor - in addition to their previously described protumor phenotype. To understand the impact of apoptotic cells on the macrophage activation state, we cocultured apoptotic lymphoma cells with classically activated macrophages (M(IFN-γ/LPS), also known as M1, macrophages). Although untreated and M(IFN-γ/LPS) macrophages were able to bind apoptotic lymphoma cells equally well, M(IFN-γ/LPS) macrophages displayed enhanced ability to phagocytose them. We found that direct exposure of M(IFN-γ/LPS) macrophages to apoptotic lymphoma cells caused switching towards a protumor activation state (often referred to as M2-like) with concomitant inhibition of antitumor activity that was a characteristic feature of M(IFN-γ/LPS) macrophages. Indeed, M(IFN-γ/LPS) macrophages exposed to apoptotic lymphoma cells displayed increased lymphoma growth-promoting activities. Antilymphoma activity by M(IFN-γ/LPS) macrophages was mediated, in part, by galectin-3, a pleiotropic glycoprotein involved in apoptotic cell clearance that is strongly expressed by lymphoma TAMs but not lymphoma cells. Intriguingly, aggressive lymphoma growth was markedly impaired in mice deficient in galectin-3, suggesting either that host galectin-3-mediated antilymphoma activity is required to sustain net tumor growth or that additional functions of galectin-3

  17. Polarizable multipolar electrostatics for cholesterol

    Science.gov (United States)

    Fletcher, Timothy L.; Popelier, Paul L. A.

    2016-08-01

    FFLUX is a novel force field under development for biomolecular modelling, and is based on topological atoms and the machine learning method kriging. Successful kriging models have been obtained for realistic electrostatics of amino acids, small peptides, and some carbohydrates but here, for the first time, we construct kriging models for a sizeable ligand of great importance, which is cholesterol. Cholesterol's mean total (internal) electrostatic energy prediction error amounts to 3.9 kJ mol-1, which pleasingly falls below the threshold of 1 kcal mol-1 often cited for accurate biomolecular modelling. We present a detailed analysis of the error distributions.

  18. Trafficking of Estrella lausannensis in human macrophages.

    Science.gov (United States)

    Rusconi, Brigida; Kebbi-Beghdadi, Carole; Greub, Gilbert

    2015-07-01

    Estrella lausannensis is a new member of the Chlamydiales order. Like other Chlamydia-related bacteria, it is able to replicate in amoebae and in fish cell lines. A preliminary study investigating the pathogenic potential of Chlamydia-related bacteria found a correlation between antibody response to E. lausannensis and pneumonia in children. To further investigate the pathogenic potential of E. lausannensis, we determined its ability to grow in human macrophages and its intracellular trafficking. The replication in macrophages resulted in viable E. lausannensis; however, it caused a significant cytopathic effect. The intracellular trafficking of E. lausannensis was analyzed by determining the interaction of the Estrella-containing inclusions with various endocytic markers as well as host organelles. The E. lausannensis inclusion escaped the endocytic pathway rapidly avoiding maturation into phagolysosomes by preventing both EEA-1 and LAMP-1 accumulation. Compared to Waddlia chondrophila, another Chlamydia-related bacteria, the recruitment of mitochondria and endoplasmic reticulum was minimal for E. lausannensis inclusions. Estrella lausannensis appears to use a distinct source of nutrients and energy compared to other members of the Chlamydiales order. In conclusion, we hypothesize that E. lausannensis has a restricted growth in human macrophages, due to its reduced capacity to control programmed cell death.

  19. Regulation of biliary cholesterol secretion and reverse cholesterol transport

    NARCIS (Netherlands)

    Dikkers, Arne

    2016-01-01

    According to the World Health Organization the number one cause of death throughout the world is cardiovascular disease. Therefore, there is an urgent need for new therapeutic strategies to prevent and treat cardiovascular disease. One possible way is to target the HDL-driven reverse cholesterol tra

  20. Regulation of biliary cholesterol secretion and reverse cholesterol transport

    NARCIS (Netherlands)

    Dikkers, Arne

    2016-01-01

    According to the World Health Organization the number one cause of death throughout the world is cardiovascular disease. Therefore, there is an urgent need for new therapeutic strategies to prevent and treat cardiovascular disease. On