101
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Expression of liver X receptor correlates with intrahepatic inflammation and fibrosis in patients with nonalcoholic fatty liver disease. Dig Dis Sci 2014; 59:2975-82. [PMID: 25102981 DOI: 10.1007/s10620-014-3289-x] [Citation(s) in RCA: 80] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/07/2014] [Accepted: 07/11/2014] [Indexed: 01/20/2023]
Abstract
BACKGROUND Liver X receptor (LXR) is an oxysterol-activated nuclear receptor involved in the control of major metabolic pathways for cholesterol homeostasis and lipogenesis. Although the role of LXR in hepatic steatosis is well known, its correlation with intrahepatic inflammation and fibrosis has not been thoroughly studied. We investigated the association between LXRα, hepatic inflammation, and fibrosis, as well as its correlation with other intrahepatic lipid transporters in patients with nonalcoholic fatty liver disease (NAFLD). METHODS We evaluated clinical characteristics including sex, age, body mass index, and laboratory findings from 40 NAFLD and 16 control patients. Immunohistochemical staining was carried out on liver biopsy samples from all patients. RESULTS The positive rate of LXRα expression was 30 % in the control group, 50 % in the NAFLD group, and 97 % in NASH groups. LXRα expression was positively correlated with not only the amount of intrahepatic fat, but also with intrahepatic inflammation and hepatic fibrosis. LXRα expression showed positive correlation with intrahepatic expression of ABCG5/8, CD36, and SREBP-1c. The expression of ABCA1, ABCG5/8, SREBP-1c, and CD36 was higher in NAFLD than in controls and there was no further increase in the NASH group. NPC1L1 was abundant in human liver. Expression of NPC1L1 was negatively correlated with intrahepatic inflammation and LXRα intensity. CONCLUSION LXR expression correlated with the degree of hepatic fat deposition, as well as with hepatic inflammation and fibrosis in NAFLD patients. Our research suggests that LXR is an attractive target for treatment and regulation of hepatic inflammation and fibrosis.
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102
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Kim GH, Oh GS, Yoon J, Lee GG, Lee KU, Kim SW. Hepatic TRAP80 selectively regulates lipogenic activity of liver X receptor. J Clin Invest 2014; 125:183-93. [PMID: 25437875 DOI: 10.1172/jci73615] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2013] [Accepted: 10/30/2014] [Indexed: 01/08/2023] Open
Abstract
Inflammation in response to excess low-density lipoproteins in the blood is an important driver of atherosclerosis development. Due to its ability to enhance ATP-binding cassette A1-dependent (ABCA1-dependent) reverse cholesterol transport (RCT), liver X receptor (LXR) is an attractive target for the treatment of atherosclerosis. However, LXR also upregulates the expression of sterol regulatory element-binding protein 1c (SREBP-1c), leading to increased hepatic triglyceride synthesis, an independent risk factor for atherosclerosis. Here, we developed a strategy to separate the favorable and unfavorable effects of LXR by exploiting the specificity of the coactivator thyroid hormone receptor-associated protein 80 (TRAP80). Using human hepatic cell lines, we determined that TRAP80 selectively promotes the transcription of SREBP-1c but not ABCA1. Adenovirus-mediated expression of shTRAP80 inhibited LXR-dependent SREBP-1c expression and RNA polymerase II recruitment to the LXR responsive element (LXRE) of SREBP-1c, but not to the LXRE of ABCA1. In murine models, liver-specific knockdown of TRAP80 ameliorated liver steatosis and hypertriglyceridemia induced by LXR activation and maintained RCT stimulation by the LXR ligand. Together, these data indicate that TRAP80 is a selective regulator of hepatic lipogenesis and is required for LXR-dependent SREBP-1c activation. Moreover, targeting the interaction between TRAP80 and LXR should facilitate the development of potential LXR agonists that effectively prevent atherosclerosis.
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103
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Liver X receptor (LXR) partial agonists: biaryl pyrazoles and imidazoles displaying a preference for LXRβ. Bioorg Med Chem Lett 2014; 25:372-7. [PMID: 25435151 DOI: 10.1016/j.bmcl.2014.11.029] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2014] [Revised: 11/05/2014] [Accepted: 11/07/2014] [Indexed: 01/01/2023]
Abstract
A series of biaryl pyrazole and imidazole Liver X Receptor (LXR) partial agonists has been synthesized displaying LXRβ selectivity. The LXRβ selective partial agonist 18 was identified with potent induction of ATP binding transporters ABCA1 and ABCG1 in human whole blood (EC50=1.2μM, 55% efficacy). In mice 18 displayed peripheral induction of ABCA1 at 3 and 10mpk doses with no significant elevation of plasma or hepatic triglycerides at these doses, showing an improved profile compared to a full pan-agonist.
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104
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Wang J, Mitsche MA, Lütjohann D, Cohen JC, Xie XS, Hobbs HH. Relative roles of ABCG5/ABCG8 in liver and intestine. J Lipid Res 2014; 56:319-30. [PMID: 25378657 PMCID: PMC4306686 DOI: 10.1194/jlr.m054544] [Citation(s) in RCA: 105] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
ABCG5 (G5) and ABCG8 (G8) form a sterol transporter that acts in liver and intestine to prevent accumulation of dietary sterols. Mutations in either G5 or G8 cause sitosterolemia, a recessive disorder characterized by sterol accumulation and premature coronary atherosclerosis. Hepatic G5G8 mediates cholesterol excretion into bile, but the function and relative importance of intestinal G5G8 has not been defined. To determine the role of intestinal G5G8, we developed liver-specific (L-G5G8(-/-)), intestine-specific (I-G5G8(-/-)), and total (G5G8(-/-)) KO mice. Tissue levels of sitosterol, the most abundant plant sterol, were >90-fold higher in G5G8(-/-) mice than in WT animals. Expression of G5G8 only in intestine or only in liver decreased tissue sterol levels by 90% when compared with G5G8(-/-) animals. Biliary sterol secretion was reduced in L-G5G8(-/-) and G5G8(-/-) mice, but not in I-G5G8(-/-) mice. Conversely, absorption of plant sterols was increased in I-G5G8(-/-) and G5G8(-/-) mice, but not in L-G5G8(-/-) mice. Reverse cholesterol transport, as assessed from the fraction of intravenously administered (3)H-cholesterol that appeared in feces, was reduced in G5G8(-/-), I-G5G8(-/-), and L-G5G8(-/-) mice. Thus, G5G8 expression in both the liver and intestine protects animals from sterol accumulation, and intestinal G5G8 contributes to extrahepatic cholesterol efflux in mice.
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Affiliation(s)
- Jin Wang
- Department of Molecular Genetics, University of Texas Southwestern Medical Center, Dallas, TX 75390
| | - Matthew A Mitsche
- Department of Molecular Genetics, University of Texas Southwestern Medical Center, Dallas, TX 75390
| | - Dieter Lütjohann
- Department of Clinical Pharmacology, University of Bonn, D-53105 Bonn, Germany
| | - Jonathan C Cohen
- Department of Internal Medicine, University of Texas Southwestern Medical Center, Dallas, TX 75390
| | - Xiao-Song Xie
- Department of Internal Medicine, University of Texas Southwestern Medical Center, Dallas, TX 75390
| | - Helen H Hobbs
- Department of Molecular Genetics, University of Texas Southwestern Medical Center, Dallas, TX 75390 Department of Internal Medicine, University of Texas Southwestern Medical Center, Dallas, TX 75390 Howard Hughes Medical Institute, University of Texas Southwestern Medical Center, Dallas, TX 75390
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105
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Hong C, Marshall SM, McDaniel AL, Graham M, Layne JD, Cai L, Scotti E, Boyadjian R, Kim J, Chamberlain BT, Tangirala RK, Jung ME, Fong L, Lee R, Young SG, Temel RE, Tontonoz P. The LXR-Idol axis differentially regulates plasma LDL levels in primates and mice. Cell Metab 2014; 20:910-918. [PMID: 25440061 PMCID: PMC4261644 DOI: 10.1016/j.cmet.2014.10.001] [Citation(s) in RCA: 67] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/28/2014] [Revised: 07/22/2014] [Accepted: 10/06/2014] [Indexed: 11/25/2022]
Abstract
The LXR-regulated E3 ubiquitin ligase IDOL controls LDLR receptor stability independent of SREBP and PCSK9, but its relevance to plasma lipid levels is unknown. Here we demonstrate that the effects of the LXR-IDOL axis are both tissue and species specific. In mice, LXR agonist induces Idol transcript levels in peripheral tissues but not in liver, and does not change plasma LDL levels. Accordingly, Idol-deficient mice exhibit elevated LDLR protein levels in peripheral tissues, but not in the liver. By contrast, LXR activation in cynomolgus monkeys induces hepatic IDOL expression, reduces LDLR protein levels, and raises plasma LDL levels. Knockdown of IDOL in monkeys with an antisense oligonucleotide blunts the effect of LXR agonist on LDL levels. These results implicate IDOL as a modulator of plasma lipid levels in primates and support further investigation into IDOL inhibition as a potential strategy for LDL lowering in humans.
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Affiliation(s)
- Cynthia Hong
- Howard Hughes Medical Institute, University of California, Los Angeles, Los Angeles, CA 90095, USA; Department of Pathology and Laboratory Medicine, University of California, Los Angeles, Los Angeles, CA 90095, USA
| | - Stephanie M Marshall
- Department of Pathology, Section on Lipid Sciences, Wake Forest University School of Medicine, Winston-Salem, NC 27157, USA
| | - Allison L McDaniel
- Department of Pathology, Section on Lipid Sciences, Wake Forest University School of Medicine, Winston-Salem, NC 27157, USA
| | - Mark Graham
- Cardiovascular Antisense Drug Discovery Group, Isis Pharmaceuticals, Carlsbad, CA 92010, USA
| | - Joseph D Layne
- Saha Cardiovascular Research Center, University of Kentucky, Lexington, KY 40536, USA
| | - Lei Cai
- Saha Cardiovascular Research Center, University of Kentucky, Lexington, KY 40536, USA
| | - Elena Scotti
- Howard Hughes Medical Institute, University of California, Los Angeles, Los Angeles, CA 90095, USA; Department of Pathology and Laboratory Medicine, University of California, Los Angeles, Los Angeles, CA 90095, USA
| | - Rima Boyadjian
- Howard Hughes Medical Institute, University of California, Los Angeles, Los Angeles, CA 90095, USA; Department of Pathology and Laboratory Medicine, University of California, Los Angeles, Los Angeles, CA 90095, USA
| | - Jason Kim
- Division of Endocrinology, Department of Medicine, University of California, Los Angeles, Los Angeles, CA 90095, USA
| | - Brian T Chamberlain
- California NanoSystems Institute, University of California, Los Angeles, Los Angeles, CA 90095, USA; Department of Chemistry and Biochemistry, University of California, Los Angeles, Los Angeles, CA 90095, USA
| | - Rajendra K Tangirala
- Division of Endocrinology, Department of Medicine, University of California, Los Angeles, Los Angeles, CA 90095, USA
| | - Michael E Jung
- California NanoSystems Institute, University of California, Los Angeles, Los Angeles, CA 90095, USA; Department of Chemistry and Biochemistry, University of California, Los Angeles, Los Angeles, CA 90095, USA
| | - Loren Fong
- Department of Medicine, University of California, Los Angeles, Los Angeles, CA 90095, USA
| | - Richard Lee
- Cardiovascular Antisense Drug Discovery Group, Isis Pharmaceuticals, Carlsbad, CA 92010, USA
| | - Stephen G Young
- Department of Medicine, University of California, Los Angeles, Los Angeles, CA 90095, USA; Department of Human Genetics, University of California, Los Angeles, Los Angeles, CA 90095, USA
| | - Ryan E Temel
- Department of Pathology, Section on Lipid Sciences, Wake Forest University School of Medicine, Winston-Salem, NC 27157, USA; Saha Cardiovascular Research Center, University of Kentucky, Lexington, KY 40536, USA.
| | - Peter Tontonoz
- Howard Hughes Medical Institute, University of California, Los Angeles, Los Angeles, CA 90095, USA; Department of Pathology and Laboratory Medicine, University of California, Los Angeles, Los Angeles, CA 90095, USA.
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106
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Zanotti I, Dall'Asta M, Mena P, Mele L, Bruni R, Ray S, Del Rio D. Atheroprotective effects of (poly)phenols: a focus on cell cholesterol metabolism. Food Funct 2014; 6:13-31. [PMID: 25367393 DOI: 10.1039/c4fo00670d] [Citation(s) in RCA: 98] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
Collated observations from several epidemiological studies have demonstrated that dietary intake of (poly)phenols from nuts, coffee, cocoa, grapes, and berries may protect against the development of atherosclerosis. Whereas this beneficial activity has previously been linked mainly to antioxidant or anti-inflammatory properties, recently emerging data suggest mechanisms by which (poly)phenolic substances can modulate cellular lipid metabolism, thereby mitigating atherosclerotic plaque formation. In this review, both experimental studies and clinical trials investigating the atheroprotective effects of the most relevant dietary (poly)phenols are critically discussed.
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Affiliation(s)
- Ilaria Zanotti
- Department of Pharmacy, University of Parma, Viale delle Scienze 27/A, 43124 Parma, Italy
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107
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SCHMIEDTOVA M, HECZKOVA M, KOVAR J, KRALOVA LESNA I, POLEDNE R. Reverse Transport of Cholesterol Is the Reason for Resistance to Development of Atherosclerosis in Prague Hereditary Hypercholesterolemic (PHHC) Rat. Physiol Res 2014; 63:591-6. [DOI: 10.33549/physiolres.932680] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022] Open
Abstract
The Prague Hereditary Hypercholesterolemic (PHHC) rat is a model of hypercholesterolemia. In previous experiments, it was found to be completely resistant to the development of atherosclerosis. It was assumed that the reverse transport of cholesterol (RCT) might be the reason for this resistance. In this study, RCT was measured in vivo by cholesterol efflux from macrophages to plasma, using previously established methods for RCT in mice (Rader 2003), optimized for measurements in rats. Primary cell culture of macrophages was labeled with 14C-cholesterol and then injected intraperitoneally into rats. Plasma and feces were collected at 24 and 48 h. The plasma 14C-cholesterol levels at both 24 and 48 h were significantly higher in male PHHC rats compared to control Wistar rats. The PHHC rats excreted less 14C-cholesterol in feces in 24 and 48 h compared to Wistar rats. The largest pool of 14C-cholesterol was found in the adipose tissue of PHHC rats and in contrast lower levels of 14C-cholesterol were measured in the liver and muscle tissues of PHHC rats compared with Wistar rats. Increasing release of 14C-cholesterol efflux from macrophages demonstrates accelerated RTC and leads to prevention of atherogenesis in PHHC rats.
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Affiliation(s)
| | | | | | | | - R. POLEDNE
- Institute of Clinical and Experimental Medicine, Prague, Czech Republic
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108
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Babič M, Schmiedtová M, Poledne R, Herynek V, Horák D. In vivo monitoring of rat macrophages labeled with poly(l-lysine)-iron oxide nanoparticles. J Biomed Mater Res B Appl Biomater 2014; 103:1141-8. [PMID: 25283523 DOI: 10.1002/jbm.b.33292] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2014] [Revised: 08/18/2014] [Accepted: 09/12/2014] [Indexed: 12/23/2022]
Abstract
Coprecipitation of FeCl2 and FeCl3 with aqueous ammonia was used to prepare iron oxide nanoparticles dispersible in aqueous medium. Oxidation of the particles with sodium hypochlorite then yielded maghemite (γ-Fe2 O3 ) nanoparticles which were coated with two types of coating -d-mannose or poly(l-lysine) (PLL) as confirmed by FTIR analysis. The particles were <10 nm according to transmission electron microscopy. Their hydrodynamic particle size was ∼180 nm (by dynamic light scattering). The d-mannose-, PLL-coated, and neat γ-Fe2 O3 particles as well as commercial Resovist® were used to label rat macrophages. The viability and contrast properties of labeled macrophages were compared. PLL-coated γ-Fe2 O3 nanoparticles were found optimal. The labeled macrophages were injected to rats monitored in vivo by magnetic resonance imaging up to 48 h. Transport of macrophages labeled with PLL-γ-Fe2 O3 nanoparticles in rats was confirmed. Tracking of macrophages using the developed particles can be used for monitoring of inflammations and cell migration in cell therapy.
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Affiliation(s)
- Michal Babič
- Institute of Macromolecular Chemistry, Department of Polymer Particles, Academy of Sciences of the Czech Republic, 162 06, Prague 6, Czech Republic
| | - Martina Schmiedtová
- Institute for Clinical and Experimental Medicine, Laboratory for Atherosclerosis Research, 140 21, Prague 4, Czech Republic
| | - Rudolf Poledne
- Institute for Clinical and Experimental Medicine, Laboratory for Atherosclerosis Research, 140 21, Prague 4, Czech Republic
| | - Vít Herynek
- Institute for Clinical and Experimental Medicine, Laboratory for Atherosclerosis Research, 140 21, Prague 4, Czech Republic.,Institute of Experimental Medicine, Academy of Sciences of the Czech Republic, Vídeňská, 1083, Czech Republic
| | - Daniel Horák
- Institute of Macromolecular Chemistry, Department of Polymer Particles, Academy of Sciences of the Czech Republic, 162 06, Prague 6, Czech Republic
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109
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Altemus JB, Patel SB, Sehayek E. Liver-specific induction of Abcg5 and Abcg8 stimulates reverse cholesterol transport in response to ezetimibe treatment. Metabolism 2014; 63:1334-41. [PMID: 25060694 DOI: 10.1016/j.metabol.2014.06.014] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/13/2014] [Revised: 06/02/2014] [Accepted: 06/17/2014] [Indexed: 11/20/2022]
Abstract
OBJECTIVE Previous studies have shown ezetimibe treatment results in a 2-6-fold increase in reverse cholesterol transport (RCT). However, recent sterol balance studies question the role of biliary sterol secretion in RCT, and challenge the hypothesis that ezetimibe increases RCT through decreased absorption of biliary cholesterol in the intestine. We set out to determine whether ezetimibe may increase RCT by mechanisms that are independent of its well-established inhibition of intestinal cholesterol absorption. METHODS C57BL/6J, Npc1l1-KO, and/or Abcg8-KO mice were fed a chow diet with or without ezetimibe and fecal [(14)C]-neutral and [(14)C]-acidic sterols were measured to examine macrophage-to-feces RCT. We measured the expression of RCT related genes in the liver and jejunum in these mice. To confirm our significant gene expression findings, we utilized primary human hepatocytes cultured with or without a glucuronated metabolite of ezetimibe. RESULTS Our studies revealed that treatment with ezetimibe was associated with increased expression of hepatic Abcg5 and Abcg8. Ezetimibe did not directly affect expression in the liver, but this expression was due to the inhibition of intestinal cholesterol absorption. This conclusion was supported by the absence of an ABCG5/ABCG8 expression response to treatment with an ezetimibe metabolite in primary human hepatocytes. Finally, we found that the ezetimibe-dependent stimulation of RCT was attenuated in the absence of Abcg8. CONCLUSIONS Our study is the first to demonstrate ezetimibe treatment cooperatively stimulated macrophage-to-feces RCT by indirectly increasing liver Abcg5/Abcg8 expression in addition to its known suppression of intestinal cholesterol absorption.
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Affiliation(s)
- Jessica B Altemus
- Genomic Medicine Institute, The Cleveland Clinic Foundation, Cleveland, OH, USA.
| | - Shailendra B Patel
- Division of Endocrinology, Clement J. Zablocki Veterans Affairs Medical Center, Milwaukee, WI, USA; Division of Endocrinology, Metabolism and Clinical Nutrition, Medical College of Wisconsin, Milwaukee, WI, USA
| | - Ephraim Sehayek
- Genomic Medicine Institute, The Cleveland Clinic Foundation, Cleveland, OH, USA
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110
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Lactobacillus acidophilus ATCC 4356 prevents atherosclerosis via inhibition of intestinal cholesterol absorption in apolipoprotein E-knockout mice. Appl Environ Microbiol 2014; 80:7496-504. [PMID: 25261526 DOI: 10.1128/aem.02926-14] [Citation(s) in RCA: 70] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023] Open
Abstract
The objective of this study was to investigate the effect of Lactobacillus acidophilus ATCC 4356 on the development of atherosclerosis in apolipoprotein E-knockout (ApoE(-/-)) mice. Eight-week-old ApoE(-/-) mice were fed a Western diet with or without L. acidophilus ATCC 4356 daily for 16 weeks. L. acidophilus ATCC 4356 protected ApoE(-/-) mice from atherosclerosis by reducing their plasma cholesterol levels from 923 ± 44 to 581 ± 18 mg/dl, likely via a marked decrease in cholesterol absorption caused by modulation of Niemann-Pick C1-like 1 (NPC1L1). In addition, suppression of cholesterol absorption induced reverse cholesterol transport (RCT) in macrophages through the peroxisome proliferator-activated receptor/liver X receptor (PPAR/LXR) pathway. Fecal lactobacillus and bifidobacterium counts were significantly (P < 0.05) higher in the L. acidophilus ATCC 4356 treatment groups than in the control groups. Furthermore, L. acidophilus ATCC 4356 was detected in the rat small intestine, colon, and feces during the feeding trial. The bacterial levels remained high even after the administration of lactic acid bacteria had been stopped for 2 weeks. These results suggest that administration of L. acidophilus ATCC 4356 can protect against atherosclerosis through the inhibition of intestinal cholesterol absorption. Therefore, L. acidophilus ATCC 4356 may be a potential therapeutic material for preventing the progression of atherosclerosis.
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111
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Allen RM, Vickers KC. Coenzyme Q10 increases cholesterol efflux and inhibits atherosclerosis through microRNAs. Arterioscler Thromb Vasc Biol 2014; 34:1795-7. [PMID: 25142877 PMCID: PMC4142520 DOI: 10.1161/atvbaha.114.303741] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Abstract
Researchers have identified a novel microRNA (miRNA) regulatory module that connects a popular vitamin-like supplement, Coenzyme Q10 (CoQ10), to ATP-cassette transport G1 (ABCG1)-mediated macrophage cholesterol efflux. CoQ10 was found to inhibit the expression of c-Jun, and thus the activity of the AP-1 complex, which was determined to be a transcriptional activator of miR-378. miR-378 directly targets ABCG1 and loss of miR-378 suppression resulted in increased cholesterol efflux and atheroprotection in mice. Here we discuss the merits of a recent study by Wang, D et al. , and place their acute observations in the current landscape of miRNA regulation of cholesterol efflux and atherosclerosis.
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Affiliation(s)
- Ryan M Allen
- From the Department of Medicine, Vanderbilt University School of Medicine, Nashville, TN
| | - Kasey C Vickers
- From the Department of Medicine, Vanderbilt University School of Medicine, Nashville, TN.
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112
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Zheng F, Zhang S, Lu W, Wu F, Yin X, Yu D, Pan Q, Li H. Regulation of insulin resistance and adiponectin signaling in adipose tissue by liver X receptor activation highlights a cross-talk with PPARγ. PLoS One 2014; 9:e101269. [PMID: 24972069 PMCID: PMC4074121 DOI: 10.1371/journal.pone.0101269] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2013] [Accepted: 06/05/2014] [Indexed: 01/15/2023] Open
Abstract
Liver X receptors (LXRs) have been recognized as a promising therapeutic target for atherosclerosis; however, their role in insulin sensitivity is controversial. Adiponectin plays a unique role in maintaining insulin sensitivity. Currently, no systematic experiments elucidating the role of LXR activation in insulin function based on adiponectin signaling have been reported. Here, we investigated the role of LXR activation in insulin resistance based on adiponectin signaling, and possible mechanisms. C57BL/6 mice maintained on a regular chow received the LXR agonist, T0901317 (30 mg/kg.d) for 3 weeks by intraperitoneal injection, and differentiated 3T3-L1 adipocytes were treated with T0901317 or GW3965. T0901317 treatment induced significant insulin resistance in C57BL/6 mice. It decreased adiponectin gene transcription in epididymal fat, as well as serum adiponectin levels. Activity of AMPK, a key mediator of adiponectin signaling, was also decreased, resulting in decreased Glut-4 membrane translocation in epididymal fat. In contrast, adiponectin activity was not changed in the liver of T0901317 treated mice. In vitro, both T0901317 and GW3965 decreased adiponectin expression in adipocytes in a dose-dependent manner, an effect which was diminished by LXRα silencing. ChIP-qPCR studies demonstrated that T0901317 decreased the binding of PPARγ to the PPAR-responsive element (PPRE) of the adiponectin promoter in a dose-dependent manner. Furthermore, T0901317 exerted an antagonistic effect on the expression of adiponectin in adipocytes co-treated with 3 µM Pioglitazone. In luciferase reporter gene assays, T0901317 dose-dependently inhibited PPRE-Luc activity in HEK293 cells co-transfected with LXRα and PPARγ. These results suggest that LXR activation induces insulin resistance with decreased adiponectin signaling in epididymal fat, probably due to negative regulation of PPARγ signaling. These findings indicate that the potential of LXR activation as a therapeutic target for atherosclerosis may be limited by the possibility of exacerbating insulin resistance-related disease.
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Affiliation(s)
- Fenping Zheng
- Department of Endocrinology, Sir Run Run Shaw Hospital Affiliated with School of Zhejiang University, Hangzhou, Zhejiang, P. R. China
| | - Saifei Zhang
- Department of Endocrinology, Sir Run Run Shaw Hospital Affiliated with School of Zhejiang University, Hangzhou, Zhejiang, P. R. China
| | - Weina Lu
- Department of Endocrinology, Sir Run Run Shaw Hospital Affiliated with School of Zhejiang University, Hangzhou, Zhejiang, P. R. China
| | - Fang Wu
- Department of Endocrinology, Sir Run Run Shaw Hospital Affiliated with School of Zhejiang University, Hangzhou, Zhejiang, P. R. China
| | - Xueyao Yin
- Department of Endocrinology, Sir Run Run Shaw Hospital Affiliated with School of Zhejiang University, Hangzhou, Zhejiang, P. R. China
| | - Dan Yu
- Department of Endocrinology, Sir Run Run Shaw Hospital Affiliated with School of Zhejiang University, Hangzhou, Zhejiang, P. R. China
| | - Qianqian Pan
- Biomedical Research Center and Key Laboratory of Biotherapy of Zhejiang Province, Sir Run Run Shaw Hospital Affiliated with School of Zhejiang University, Hangzhou, Zhejiang, P.R. China
| | - Hong Li
- Department of Endocrinology, Sir Run Run Shaw Hospital Affiliated with School of Zhejiang University, Hangzhou, Zhejiang, P. R. China
- * E-mail:
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113
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Breevoort SR, Angdisen J, Schulman IG. Macrophage-independent regulation of reverse cholesterol transport by liver X receptors. Arterioscler Thromb Vasc Biol 2014; 34:1650-60. [PMID: 24947527 DOI: 10.1161/atvbaha.114.303383] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
OBJECTIVE The ability of high-density lipoprotein (HDL) particles to accept cholesterol from peripheral cells, such as lipid-laden macrophages, and to transport cholesterol to the liver for catabolism and excretion in a process termed reverse cholesterol transport (RCT) is thought to underlie the beneficial cardiovascular effects of elevated HDL. The liver X receptors (LXRs; LXRα and LXRβ) regulate RCT by controlling the efflux of cholesterol from macrophages to HDL and the excretion, catabolism, and absorption of cholesterol in the liver and intestine. Importantly, treatment with LXR agonists increases RCT and decreases atherosclerosis in animal models. Nevertheless, LXRs are expressed in multiple tissues involved in RCT, and their tissue-specific contributions to RCT are still not well defined. APPROACH AND RESULTS Using tissue-specific LXR deletions together with in vitro and in vivo assays of cholesterol efflux and fecal cholesterol excretion, we demonstrate that macrophage LXR activity is neither necessary nor sufficient for LXR agonist-stimulated RCT. In contrast, the ability of LXR agonists primarily acting in the intestine to increase HDL mass and HDL function seems to underlie the ability of LXR agonists to stimulate RCT in vivo. CONCLUSIONS We demonstrate that activation of LXR in macrophages makes little or no contribution to LXR agonist-stimulated RCT. Unexpectedly, our studies suggest that the ability of macrophages to efflux cholesterol to HDL in vivo is not regulated by macrophage activity but is primarily determined by the quantity and functional activity of HDL.
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Affiliation(s)
- Sarah R Breevoort
- From the Department of Pharmacology, University of Virginia, Charlottesville
| | - Jerry Angdisen
- From the Department of Pharmacology, University of Virginia, Charlottesville
| | - Ira G Schulman
- From the Department of Pharmacology, University of Virginia, Charlottesville.
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114
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Xu Y, Liu Q, Xu Y, Liu C, Wang X, He X, Zhu N, Liu J, Wu Y, Li Y, Li N, Feng T, Lai F, Zhang M, Hong B, Jiang JD, Si S. Rutaecarpine suppresses atherosclerosis in ApoE-/- mice through upregulating ABCA1 and SR-BI within RCT. J Lipid Res 2014; 55:1634-47. [PMID: 24908654 DOI: 10.1194/jlr.m044198] [Citation(s) in RCA: 51] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2013] [Indexed: 11/20/2022] Open
Abstract
ABCA1 and scavenger receptor class B type I (SR-BI)/CD36 and lysosomal integral membrane protein II analogous 1 (CLA-1) are the key transporter and receptor in reverse cholesterol transport (RCT). Increasing the expression level of ABCA1 and SR-BI/CLA-1 is antiatherogenic. The aim of the study was to find novel antiatherosclerotic agents upregulating expression of ABCA1 and SR-BI/CLA-1 from natural compounds. Using the ABCA1p-LUC and CLA-1p-LUC HepG2 cell lines, we found that rutaecarpine (RUT) triggered promoters of ABCA1 and CLA-1 genes. RUT increased ABCA1 and SR-BI/CLA-1 expression in vitro related to liver X receptor alpha and liver X receptor beta. RUT induced cholesterol efflux in RAW264.7 cells. ApoE-deficient (ApoE(-/-)) mice treated with RUT for 8 weeks showed ∼68.43, 70.23, and 85.56% less en face lesions for RUT (L), RUT (M), and RUT (H) groups, respectively, compared with the model group. Mouse macrophage-specific antibody and filipin staining indicated that RUT attenuated macrophages and cholesterol accumulations in atherosclerotic lesions, respectively. Additionally, ABCA1 and SR-BI expression was highly induced by RUT in livers of ApoE(-/-) mice. Meanwhile, RUT treatment significantly increased the fecal (3)H-cholesterol excretion, which demonstrated that RUT could promote RCT in vivo. RUT was identified to be a candidate that protected ApoE(-/-) mice from developing atherosclerosis through preferentially promoting activities of ABCA1 and SR-BI within RCT.
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Affiliation(s)
- Yanni Xu
- Institute of Medicinal Biotechnology Chinese Academy of Medical Sciences & Peking Union Medical College, Beijing 100050, China
| | - Qi Liu
- Institute of Medicinal Biotechnology Chinese Academy of Medical Sciences & Peking Union Medical College, Beijing 100050, China
| | - Yang Xu
- Institute of Medicinal Biotechnology Chinese Academy of Medical Sciences & Peking Union Medical College, Beijing 100050, China
| | - Chang Liu
- Institute of Medicinal Biotechnology Chinese Academy of Medical Sciences & Peking Union Medical College, Beijing 100050, China
| | - Xiao Wang
- Institute of Medicinal Biotechnology Chinese Academy of Medical Sciences & Peking Union Medical College, Beijing 100050, China
| | - Xiaobo He
- Institute of Medicinal Biotechnology Chinese Academy of Medical Sciences & Peking Union Medical College, Beijing 100050, China
| | - Ningyu Zhu
- Institute of Medicinal Biotechnology Chinese Academy of Medical Sciences & Peking Union Medical College, Beijing 100050, China
| | - Jikai Liu
- Institute of Medicinal Biotechnology Chinese Academy of Medical Sciences & Peking Union Medical College, Beijing 100050, China
| | - Yexiang Wu
- Institute of Medicinal Biotechnology Chinese Academy of Medical Sciences & Peking Union Medical College, Beijing 100050, China
| | - Yongzhen Li
- Institute of Medicinal Biotechnology Chinese Academy of Medical Sciences & Peking Union Medical College, Beijing 100050, China
| | - Ni Li
- Institute of Medicinal Biotechnology Chinese Academy of Medical Sciences & Peking Union Medical College, Beijing 100050, China
| | - Tingting Feng
- Institute of Medicinal Biotechnology Chinese Academy of Medical Sciences & Peking Union Medical College, Beijing 100050, China
| | - Fangfang Lai
- State Key Laboratory of Bioactive Substance and Function of Natural Medicines, Institute of Materia Medica, Chinese Academy of Medical Sciences & Peking Union Medical College, Beijing 100050, China
| | - Murui Zhang
- Sir Runrun Shaw Hospital of Zhejiang University, Hangzhou, Zhejiang Province 310016, China
| | - Bin Hong
- Institute of Medicinal Biotechnology Chinese Academy of Medical Sciences & Peking Union Medical College, Beijing 100050, China
| | - Jian-Dong Jiang
- Institute of Medicinal Biotechnology Chinese Academy of Medical Sciences & Peking Union Medical College, Beijing 100050, China State Key Laboratory of Bioactive Substance and Function of Natural Medicines, Institute of Materia Medica, Chinese Academy of Medical Sciences & Peking Union Medical College, Beijing 100050, China
| | - Shuyi Si
- Institute of Medicinal Biotechnology Chinese Academy of Medical Sciences & Peking Union Medical College, Beijing 100050, China
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Tice CM, Noto PB, Fan KY, Zhuang L, Lala DS, Singh SB. The Medicinal Chemistry of Liver X Receptor (LXR) Modulators. J Med Chem 2014; 57:7182-205. [PMID: 24832115 DOI: 10.1021/jm500442z] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Affiliation(s)
- Colin M. Tice
- Vitae Pharmaceuticals Inc., 502 West Office Center Drive, Fort Washington, Pennsylvania 19034, United States
| | - Paul B. Noto
- Vitae Pharmaceuticals Inc., 502 West Office Center Drive, Fort Washington, Pennsylvania 19034, United States
| | - Kristi Yi Fan
- Vitae Pharmaceuticals Inc., 502 West Office Center Drive, Fort Washington, Pennsylvania 19034, United States
| | - Linghang Zhuang
- Vitae Pharmaceuticals Inc., 502 West Office Center Drive, Fort Washington, Pennsylvania 19034, United States
| | - Deepak S. Lala
- Vitae Pharmaceuticals Inc., 502 West Office Center Drive, Fort Washington, Pennsylvania 19034, United States
| | - Suresh B. Singh
- Vitae Pharmaceuticals Inc., 502 West Office Center Drive, Fort Washington, Pennsylvania 19034, United States
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116
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Hong C, Tontonoz P. Liver X receptors in lipid metabolism: opportunities for drug discovery. Nat Rev Drug Discov 2014; 13:433-44. [DOI: 10.1038/nrd4280] [Citation(s) in RCA: 401] [Impact Index Per Article: 40.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
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117
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118
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Wang D, Yan X, Xia M, Yang Y, Li D, Li X, Song F, Ling W. Coenzyme Q10 promotes macrophage cholesterol efflux by regulation of the activator protein-1/miR-378/ATP-binding cassette transporter G1-signaling pathway. Arterioscler Thromb Vasc Biol 2014; 34:1860-70. [PMID: 24675662 DOI: 10.1161/atvbaha.113.302879] [Citation(s) in RCA: 56] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
OBJECTIVE Recent studies have shown the role of miRNAs in macrophage reverse cholesterol transport and atherogenesis. We hypothesized that coenzyme Q10 (CoQ10) may increase macrophage reverse cholesterol transport by regulating miRNA expression that contributes to the prevention of atherosclerosis. APPROACH AND RESULTS CoQ10 treatment suppressed oxidized low-density lipoprotein-induced macrophage foam cell formation by ameliorating the binding of activator protein-1 to the putative promoter region of miR-378 primary transcript, thus decreasing the miR-378 level and enhancing the ATP-binding cassette transporter G1-mediated macrophage cholesterol efflux to high-density lipoprotein. Subsequently, the axis of activator protein-1/miR-378/ATP-binding cassette transporter G1 cholesterol efflux was confirmed in peritoneal macrophages isolated from CoQ10-treated apolipoprotein E-deficient mice. Finally, CoQ10 consumption promoted macrophage reverse cholesterol transport and inhibited the progression of atherosclerosis in apolipoprotein E-deficient mice. CONCLUSIONS This study identified activator protein-1/miR-378/ATP-binding cassette transporter G1 as a novel cascade for CoQ10 in facilitating macrophage cholesterol efflux in vitro and in vivo. Our data thus imply that both CoQ10 and miR-378 are promising candidates for atherosclerosis prevention and treatment.
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Affiliation(s)
- Dongliang Wang
- From the Department of Nutrition, School of Public Health, Sun Yat-Sen University (Northern Campus), Guangzhou, Guangdong Province, People's Republic of China (D.W., X.Y., M.X., Y.Y., D.L., X.L., F.S., W.L.); and Guangdong Provincial Key Laboratory of Food, Nutrition and Health, Department of Nutrition, School of Public Health, Sun Yat-Sen University (Northern Campus), Guangzhou, Guangdong Province, People's Republic of China (D.W., M.X., Y.Y., D.L., W.L.)
| | - Xiao Yan
- From the Department of Nutrition, School of Public Health, Sun Yat-Sen University (Northern Campus), Guangzhou, Guangdong Province, People's Republic of China (D.W., X.Y., M.X., Y.Y., D.L., X.L., F.S., W.L.); and Guangdong Provincial Key Laboratory of Food, Nutrition and Health, Department of Nutrition, School of Public Health, Sun Yat-Sen University (Northern Campus), Guangzhou, Guangdong Province, People's Republic of China (D.W., M.X., Y.Y., D.L., W.L.)
| | - Min Xia
- From the Department of Nutrition, School of Public Health, Sun Yat-Sen University (Northern Campus), Guangzhou, Guangdong Province, People's Republic of China (D.W., X.Y., M.X., Y.Y., D.L., X.L., F.S., W.L.); and Guangdong Provincial Key Laboratory of Food, Nutrition and Health, Department of Nutrition, School of Public Health, Sun Yat-Sen University (Northern Campus), Guangzhou, Guangdong Province, People's Republic of China (D.W., M.X., Y.Y., D.L., W.L.)
| | - Yan Yang
- From the Department of Nutrition, School of Public Health, Sun Yat-Sen University (Northern Campus), Guangzhou, Guangdong Province, People's Republic of China (D.W., X.Y., M.X., Y.Y., D.L., X.L., F.S., W.L.); and Guangdong Provincial Key Laboratory of Food, Nutrition and Health, Department of Nutrition, School of Public Health, Sun Yat-Sen University (Northern Campus), Guangzhou, Guangdong Province, People's Republic of China (D.W., M.X., Y.Y., D.L., W.L.)
| | - Dan Li
- From the Department of Nutrition, School of Public Health, Sun Yat-Sen University (Northern Campus), Guangzhou, Guangdong Province, People's Republic of China (D.W., X.Y., M.X., Y.Y., D.L., X.L., F.S., W.L.); and Guangdong Provincial Key Laboratory of Food, Nutrition and Health, Department of Nutrition, School of Public Health, Sun Yat-Sen University (Northern Campus), Guangzhou, Guangdong Province, People's Republic of China (D.W., M.X., Y.Y., D.L., W.L.)
| | - Xinrui Li
- From the Department of Nutrition, School of Public Health, Sun Yat-Sen University (Northern Campus), Guangzhou, Guangdong Province, People's Republic of China (D.W., X.Y., M.X., Y.Y., D.L., X.L., F.S., W.L.); and Guangdong Provincial Key Laboratory of Food, Nutrition and Health, Department of Nutrition, School of Public Health, Sun Yat-Sen University (Northern Campus), Guangzhou, Guangdong Province, People's Republic of China (D.W., M.X., Y.Y., D.L., W.L.)
| | - Fenglin Song
- From the Department of Nutrition, School of Public Health, Sun Yat-Sen University (Northern Campus), Guangzhou, Guangdong Province, People's Republic of China (D.W., X.Y., M.X., Y.Y., D.L., X.L., F.S., W.L.); and Guangdong Provincial Key Laboratory of Food, Nutrition and Health, Department of Nutrition, School of Public Health, Sun Yat-Sen University (Northern Campus), Guangzhou, Guangdong Province, People's Republic of China (D.W., M.X., Y.Y., D.L., W.L.)
| | - Wenhua Ling
- From the Department of Nutrition, School of Public Health, Sun Yat-Sen University (Northern Campus), Guangzhou, Guangdong Province, People's Republic of China (D.W., X.Y., M.X., Y.Y., D.L., X.L., F.S., W.L.); and Guangdong Provincial Key Laboratory of Food, Nutrition and Health, Department of Nutrition, School of Public Health, Sun Yat-Sen University (Northern Campus), Guangzhou, Guangdong Province, People's Republic of China (D.W., M.X., Y.Y., D.L., W.L.).
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Bravo-Nuevo A, Marcy A, Huang M, Kappler F, Mulgrew J, Laury-Kleintop L, Reichman M, Tobia A, Prendergast GC. Meglumine exerts protective effects against features of metabolic syndrome and type II diabetes. PLoS One 2014; 9:e90031. [PMID: 24587200 PMCID: PMC3937407 DOI: 10.1371/journal.pone.0090031] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2013] [Accepted: 01/30/2014] [Indexed: 11/19/2022] Open
Abstract
Metabolic syndrome, diabetes and diabetes complications pose a growing medical challenge worldwide, accentuating the need of safe and effective strategies for their clinical management. Here we present preclinical evidence that the sorbitol derivative meglumine (N-methyl-D-glucamine) can safely protect against several features of metabolic syndrome and diabetes, as well as elicit enhancement in muscle stamina. Meglumine is a compound routinely used as an approved excipient to improve drug absorption that has not been ascribed any direct biological effects in vivo. Normal mice (SV129) administered 18 mM meglumine orally for six weeks did not display any gastrointestinal or other observable adverse effects, but had a marked effect on enhancing muscle stamina and at longer times in limiting weight gain. In the established KK.Cg-Ay/J model of non-insulin dependent diabetes, oral administration of meglumine significantly improved glycemic control and significantly lowered levels of plasma and liver triglycerides. Compared to untreated control animals, meglumine reduced apparent diabetic nephropathy. Sorbitol can improve blood glucose uptake by liver and muscle in a manner associated with upregulation of the AMPK-related enzyme SNARK, but with undesirable gastrointestinal side effects not seen with meglumine. In murine myoblasts, we found that meglumine increased steady-state SNARK levels in a dose-dependent manner more potently than sorbitol. Taken together, these findings provide support for the clinical evaluation of meglumine as a low-cost, safe supplement offering the potential to improve muscle function, limit metabolic syndrome and reduce diabetic complications.
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Affiliation(s)
- Arturo Bravo-Nuevo
- Lankenau Institute for Medical Research (LIMR), Wynnewood, Pennsylvania, United States of America
- * E-mail:
| | - Alice Marcy
- Dynamis Pharmaceuticals Co. Inc., Jenkintown, Pennsylvania, United States of America
| | - Minzhou Huang
- Lankenau Institute for Medical Research (LIMR), Wynnewood, Pennsylvania, United States of America
| | - Frank Kappler
- Dynamis Pharmaceuticals Co. Inc., Jenkintown, Pennsylvania, United States of America
| | - Jennifer Mulgrew
- Lankenau Institute for Medical Research (LIMR), Wynnewood, Pennsylvania, United States of America
| | - Lisa Laury-Kleintop
- Lankenau Institute for Medical Research (LIMR), Wynnewood, Pennsylvania, United States of America
| | - Melvin Reichman
- LIMR Chemical Genomics Center Inc., Wynnewood, Pennsylvania, United States of America
| | - Annette Tobia
- Dynamis Pharmaceuticals Co. Inc., Jenkintown, Pennsylvania, United States of America
| | - George C. Prendergast
- Lankenau Institute for Medical Research (LIMR), Wynnewood, Pennsylvania, United States of America
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120
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XUE XIEHUA, CHEN TONG, WEI WEI, ZHOU XIAOMAO, LIN ZHICHENG, CHEN LIDIAN. Effects of Alisma Decoction on lipid metabolism and inflammatory response are mediated through the activation of the LXRα pathway in macrophage-derived foam cells. Int J Mol Med 2014; 33:971-7. [DOI: 10.3892/ijmm.2014.1646] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2013] [Accepted: 01/31/2014] [Indexed: 11/06/2022] Open
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121
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Parikh M, Patel K, Soni S, Gandhi T. Liver X Receptor: A Cardinal Target for Atherosclerosis and Beyond. J Atheroscler Thromb 2014. [DOI: 10.5551/jat.19778] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023] Open
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122
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Valanti E, Tsompanidis A, Sanoudou D. Pharmacogenomics in the development and characterization of atheroprotective drugs. Methods Mol Biol 2014; 1175:259-300. [PMID: 25150873 DOI: 10.1007/978-1-4939-0956-8_11] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
Atherosclerosis is the main cause of cardiovascular disease (CVD) and can lead to stroke, myocardial infarction, and death. The clinically available atheroprotective drugs aim mainly at reducing the levels of circulating low-density lipoprotein (LDL), increasing high-density lipoprotein (HDL), and attenuating inflammation. However, the cardiovascular risk remains high, along with morbidity, mortality, and incidence of adverse drug events. Pharmacogenomics is increasingly contributing towards the characterization of existing atheroprotective drugs, the evaluation of novel ones, and the identification of promising, unexplored therapeutic targets, at the global molecular pathway level. This chapter presents highlights of pharmacogenomics investigations and discoveries that have contributed towards the elucidation of pharmacological atheroprotection, while opening the way to new therapeutic approaches.
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Affiliation(s)
- Efi Valanti
- Department of Pharmacology, Medical School, National and Kapodistrian University of Athens, Mikras Asias 75, Athens, 115 27, Greece
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123
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Li N, Xu Y, Feng T, Liu C, Li Y, Wang X, Si S. Identification of a Selective Agonist for Liver X Receptor α (LXRα) via Screening of a Synthetic Compound Library. ACTA ACUST UNITED AC 2013; 19:566-74. [DOI: 10.1177/1087057113516004] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023]
Abstract
Liver X receptor α (LXRα) plays an important role in reverse cholesterol transport (RCT), and activation of LXRα could reduce atherosclerosis. In the present study, we developed a screening method to identify new potential LXRα agonists using an LXRα-GAL4 chimera reporter assay. A novel analogue of N,N-disubstituted 2,8-diazaspiro[4.5]decane, IMB-151, was identified as an LXRα agonist by using this method. IMB-151 showed a significant activation effect on LXRα, with an EC50 value of 1.47 µM. IMB-151 also increased the expression of ATP-binding cassette transporter A1 (ABCA1) and G1 (ABCG1) in RAW264.7 macrophages. The upregulating effects of IMB-151 on ABCA1 and ABCG1 markedly decreased when coincubated with geranylgeranyl pyrophosphate (GGPP) ammonium salt or LXRα small interfering RNA (siRNA). Our data indicated that the upregulation of ABCA1 and ABCG1 by IMB-151 depended on activation of LXRα. Moreover, IMB-151 significantly reduced cellular lipid accumulation and increased cholesterol efflux in RAW264.7 macrophages. Interestingly, IMB-151 slightly increased sterol response element binding protein 1c (SREBP-1c) protein expression levels in HepG2 cells compared with TO901317, and this indicated that IMB-151 might have less lipogenesis side effect in vivo. These results suggested that IMB-151 was identified as a selective agonist for LXRα by using a screening method and could be used as a potential antiatherosclerotic lead compound in the future.
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Affiliation(s)
- Ni Li
- Institute of Medicinal Biotechnology, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China
| | - Yanni Xu
- Institute of Medicinal Biotechnology, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China
| | - Tingting Feng
- Institute of Medicinal Biotechnology, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China
| | - Chang Liu
- Institute of Medicinal Biotechnology, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China
| | - Yongzhen Li
- Institute of Medicinal Biotechnology, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China
| | - Xiao Wang
- Institute of Medicinal Biotechnology, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China
| | - Shuyi Si
- Institute of Medicinal Biotechnology, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China
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Liu M, Seo J, Allegood J, Bi X, Zhu X, Boudyguina E, Gebre AK, Avni D, Shah D, Sorci-Thomas MG, Thomas MJ, Shelness GS, Spiegel S, Parks JS. Hepatic apolipoprotein M (apoM) overexpression stimulates formation of larger apoM/sphingosine 1-phosphate-enriched plasma high density lipoprotein. J Biol Chem 2013; 289:2801-14. [PMID: 24318881 DOI: 10.1074/jbc.m113.499913] [Citation(s) in RCA: 60] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022] Open
Abstract
Apolipoprotein M (apoM), a lipocalin family member, preferentially associates with plasma HDL and binds plasma sphingosine 1-phosphate (S1P), a signaling molecule active in immune homeostasis and endothelial barrier function. ApoM overexpression in ABCA1-expressing HEK293 cells stimulated larger nascent HDL formation, compared with cells that did not express apoM; however, the in vivo role of apoM in HDL metabolism remains poorly understood. To test whether hepatic apoM overexpression increases plasma HDL size, we generated hepatocyte-specific apoM transgenic (APOM Tg) mice, which had an ∼3-5-fold increase in plasma apoM levels compared with wild-type mice. Although HDL cholesterol concentrations were similar to wild-type mice, APOM Tg mice had larger plasma HDLs enriched in apoM, cholesteryl ester, lecithin:cholesterol acyltransferase, and S1P. Despite the presence of larger plasma HDLs in APOM Tg mice, in vivo macrophage reverse cholesterol transport capacity was similar to that in wild-type mice. APOM Tg mice had an ∼5-fold increase in plasma S1P, which was predominantly associated with larger plasma HDLs. Primary hepatocytes from APOM Tg mice generated larger nascent HDLs and displayed increased sphingolipid synthesis and S1P secretion. Inhibition of ceramide synthases in hepatocytes increased cellular S1P levels but not S1P secretion, suggesting that apoM is rate-limiting in the export of hepatocyte S1P. Our data indicate that hepatocyte-specific apoM overexpression generates larger nascent HDLs and larger plasma HDLs, which preferentially bind apoM and S1P, and stimulates S1P biosynthesis for secretion. The unique apoM/S1P-enriched plasma HDL may serve to deliver S1P to extrahepatic tissues for atheroprotection and may have other as yet unidentified functions.
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Affiliation(s)
- Mingxia Liu
- From the Departments of Pathology-Lipid Sciences and
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125
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Silva AR, Aguilar EC, Alvarez-Leite JI, da Silva RF, Arantes RME, Bader M, Alenina N, Pelli G, Lenglet S, Galan K, Montecucco F, Mach F, Santos SHS, Santos RAS. Mas receptor deficiency is associated with worsening of lipid profile and severe hepatic steatosis in ApoE-knockout mice. Am J Physiol Regul Integr Comp Physiol 2013; 305:R1323-30. [DOI: 10.1152/ajpregu.00249.2013] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
Abstract
The classical renin-angiotensin system pathway has been recently updated with the identification of additional molecules [such as angiotensin converting enzyme 2, ANG-(1–7), and Mas receptor] that might improve some pathophysiological processes in chronic inflammatory diseases. In the present study, we focused on the potential protective role of Mas receptor activation on mouse lipid profile, liver steatosis, and atherogenesis. Mas/apolipoprotein E (ApoE)-double-knockout (DKO) mice (based on C57BL/6 strain of 20 wk of age) were fed under normal diet and compared with aged-matched Mas and ApoE-single-knockout (KO), as well as wild-type mice. Mas/ApoE double deficiency was associated with increased serum levels of atherogenic fractions of cholesterol, triglycerides, and fasting glucose compared with wild-type or single KO. Serum levels of HDL or leptin in DKO were lower than in other groups. Hepatic lipid content as well as alanine aminotransferase serum levels were increased in DKO compared with wild-type or single-KO animals. Accordingly, the hepatic protein content of mediators related to atherosclerotic inflammation, such as peroxisome proliferator-activated receptor-α and liver X receptor, was altered in an adverse way in DKO compared with ApoE-KO. On the other hand, DKO mice did not display increased atherogenesis and intraplaque inflammation compared with ApoE-KO group. In conclusion, Mas deletion in ApoE-KO mice was associated with development of severe liver steatosis and dyslipidemia without affecting concomitant atherosclerosis. Mas receptor activation might represent promising strategies for future treatments targeting both hepatic and metabolic alterations in chronic conditions clustering these disorders.
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Affiliation(s)
- Analina R. Silva
- INCT-NanoBiofar, Department of Physiology and Biophysics, Biological Sciences Institute, Federal University of Minas Gerais, Belo Horizonte, Minas Gerais, Brazil
| | - Edenil C. Aguilar
- Department of Biochemistry, Biological Sciences Institute, Federal University of Minas Gerais, Belo Horizonte, Minas Gerais, Brazil
| | - Jacqueline I. Alvarez-Leite
- Department of Biochemistry, Biological Sciences Institute, Federal University of Minas Gerais, Belo Horizonte, Minas Gerais, Brazil
| | - Rafaela F. da Silva
- INCT-NanoBiofar, Department of Physiology and Biophysics, Biological Sciences Institute, Federal University of Minas Gerais, Belo Horizonte, Minas Gerais, Brazil
| | - Rosa M. E. Arantes
- Department of Pathology, Biological Sciences Institute, Federal University of Minas Gerais, Belo Horizonte, Minas Gerais, Brazil
| | - Michael Bader
- Max-Delbrück Center for Molecular Medicine, Berlin, Germany
| | | | - Graziano Pelli
- Cardiology Division, Faculty of Medicine, University of Geneva, Geneva, Switzerland
| | - Sébastien Lenglet
- Cardiology Division, Faculty of Medicine, University of Geneva, Geneva, Switzerland
| | - Katia Galan
- Cardiology Division, Faculty of Medicine, University of Geneva, Geneva, Switzerland
| | - Fabrizio Montecucco
- Cardiology Division, Faculty of Medicine, University of Geneva, Geneva, Switzerland
- First Medical Clinic, Laboratory of Phagocyte Physiopathology and Inflammation, Department of Internal Medicine, University of Genoa, Genoa, Italy; and
| | - François Mach
- Cardiology Division, Faculty of Medicine, University of Geneva, Geneva, Switzerland
| | - Sérgio H. S. Santos
- Department of Pharmacology, Biological Sciences Institute, Federal University of Minas Gerais, Belo Horizonte, Minas Gerais, Brazil
| | - Robson A. S. Santos
- INCT-NanoBiofar, Department of Physiology and Biophysics, Biological Sciences Institute, Federal University of Minas Gerais, Belo Horizonte, Minas Gerais, Brazil
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van der Stoep M, Li Z, Calpe-Berdiel L, van der Sluis RJ, Saleh P, McKinnon HJ, Smit MJ, Korporaal SJ, Van Berkel TJ, Van Eck M, Hoekstra M. Elimination of macrophages drives LXR-induced regression both in initial and advanced stages of atherosclerotic lesion development. Biochem Pharmacol 2013; 86:1594-602. [DOI: 10.1016/j.bcp.2013.09.019] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2013] [Revised: 09/20/2013] [Accepted: 09/23/2013] [Indexed: 10/26/2022]
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127
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Lichtenstein L, Serhan N, Annema W, Combes G, Robaye B, Boeynaems JM, Perret B, Tietge UJF, Laffargue M, Martinez LO. Lack of P2Y13 in mice fed a high cholesterol diet results in decreased hepatic cholesterol content, biliary lipid secretion and reverse cholesterol transport. Nutr Metab (Lond) 2013; 10:67. [PMID: 24476490 PMCID: PMC4029266 DOI: 10.1186/1743-7075-10-67] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2013] [Accepted: 10/30/2013] [Indexed: 01/11/2023] Open
Abstract
Background The protective effect of HDL is mostly attributed to their metabolic function in reverse cholesterol transport (RCT), a process whereby excess cellular cholesterol is taken up from peripheral cells, processed in HDL particles, and later delivered to the liver for further metabolism and biliary secretion. Mechanistically, the purinergic P2Y13 ADP-receptor is involved in hepatic HDL endocytosis (i.e., uptake of both HDL protein + lipid moieties), which is considered an important step of RCT. Accordingly, chow-fed P2Y13 knockout (P2Y13-/-) mice exhibit lower hepatic HDL uptake, which translates into a decrease of hepatic free cholesterol content and biliary cholesterol and phospholipid secretion. Findings The aim of this study was to determine the effect of high cholesterol diet (HCD) in P2Y13-/- mice, in order to mimic high dietary cholesterol intake, which is a major cause of dyslipidemia in humans. As previously reported with chow-diet, HCD did not affect plasma lipid levels in P2Y13-/- compared with control mice but decreased hepatic free and esterified cholesterol content (p < 0.05, P2Y13-/- versus control). Interestingly, biliary lipid secretion and macrophages-to-feces RCT were more dramatically impaired in P2Y13-/- mice fed a HCD than chow-diet. HCD did not enhance atherosclerosis in P2Y13-/- compared with control mice. Conclusion This study demonstrates that high dietary cholesterol intake accentuated the metabolic phenotype of P2Y13-/- mice, with impaired hepatobiliary RCT. Although other animal models might be required to further evaluate the role of P2Y13 receptor in atherosclerosis, P2Y13 appears a promising target for therapeutic intervention aiming to stimulate RCT, particularly in individuals with lipid-rich diet.
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Affiliation(s)
- Laeticia Lichtenstein
- INSERM, UMR 1048, Institut des Maladies Métaboliques et Cardiovasculaires, Toulouse 31432, France.,Université de Toulouse III, UMR 1048, Toulouse 31300, France
| | - Nizar Serhan
- INSERM, UMR 1048, Institut des Maladies Métaboliques et Cardiovasculaires, Toulouse 31432, France.,Université de Toulouse III, UMR 1048, Toulouse 31300, France
| | - Wijtske Annema
- Department of Pediatrics, University of Groningen, University Medical Center Groningen, Groningen, Netherlands
| | - Guillaume Combes
- INSERM, UMR 1048, Institut des Maladies Métaboliques et Cardiovasculaires, Toulouse 31432, France.,Université de Toulouse III, UMR 1048, Toulouse 31300, France
| | - Bernard Robaye
- Institute of Interdisciplinary Research, IRIBHM, Université Libre de Bruxelles, Gosselies, Belgium
| | - Jean-Marie Boeynaems
- Institute of Interdisciplinary Research, IRIBHM, Université Libre de Bruxelles, Gosselies, Belgium
| | - Bertrand Perret
- INSERM, UMR 1048, Institut des Maladies Métaboliques et Cardiovasculaires, Toulouse 31432, France.,CHU de Toulouse, Hôpital Purpan, Toulouse, France
| | - Uwe J F Tietge
- Department of Pediatrics, University of Groningen, University Medical Center Groningen, Groningen, Netherlands
| | - Muriel Laffargue
- INSERM, UMR 1048, Institut des Maladies Métaboliques et Cardiovasculaires, Toulouse 31432, France.,Université de Toulouse III, UMR 1048, Toulouse 31300, France
| | - Laurent O Martinez
- INSERM, UMR 1048, Institut des Maladies Métaboliques et Cardiovasculaires, Toulouse 31432, France.,Université de Toulouse III, UMR 1048, Toulouse 31300, France.,CHU de Toulouse, Hôpital Purpan, Toulouse, France
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128
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Kannisto K, Gåfvels M, Jiang ZY, Slätis K, Hu X, Jorns C, Steffensen KR, Eggertsen G. LXR driven induction of HDL-cholesterol is independent of intestinal cholesterol absorption and ABCA1 protein expression. Lipids 2013; 49:71-83. [PMID: 24163219 DOI: 10.1007/s11745-013-3853-8] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2013] [Accepted: 10/08/2013] [Indexed: 12/01/2022]
Abstract
We investigated whether: (1) liver X receptor (LXR)-driven induction of high-density lipoprotein cholesterol (HDL-C) and other LXR-mediated effects on cholesterol metabolism depend on intestinal cholesterol absorption; and (2) combined treatment with the LXR agonist GW3965 and the cholesterol absorption inhibitor ezetimibe results in synergistic effects on cholesterol metabolism that could be beneficial for treatment of atherosclerosis. Mice were fed 0.2 % cholesterol and treated with GW3965+ezetimibe, GW3965 or ezetimibe. GW3965+ezetimibe treatment elevated serum HDL-C and Apolipoprotein (Apo) AI, effectively reduced the intestinal cholesterol absorption and increased the excretion of faecal neutral sterols. No changes in intestinal ATP-binding cassette (ABC) A1 or ABCG5 protein expression were observed, despite increased mRNA expression, while hepatic ABCA1 was slightly reduced. The combined treatment caused a pronounced down-regulation of intestinal Niemann-Pick C1-like 1 (NPC1L1) and reduced hepatic and intestinal cholesterol levels. GW3965 did not affect the intestinal cholesterol absorption, but increased serum HDL-C and ApoAI levels. GW3965 also increased Apoa1 mRNA levels in primary mouse hepatocytes and HEPA1-6 cells. Ezetimibe reduced the intestinal cholesterol absorption, ABCA1 and ABCG5, but did not affect the serum HDL-C or ApoAI levels. Thus, the LXR-driven induction of HDL-C and ApoAI was independent of the intestinal cholesterol absorption and increased expression of intestinal or hepatic ABCA1 was not required. Inhibited influx of cholesterol via NPC1L1 and/or low levels of intracellular cholesterol prevented post-transcriptional expression of intestinal ABCA1 and ABCG5, despite increased mRNA levels. Combined LXR activation and blocked intestinal cholesterol absorption induced effective faecal elimination of cholesterol.
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Affiliation(s)
- Kristina Kannisto
- Division of Clinical Chemistry, Department of Laboratory Medicine, Karolinska Institutet, Karolinska University Hospital, Huddinge, 141 86, Stockholm, Sweden
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129
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Toth PP, Barter PJ, Rosenson RS, Boden WE, Chapman MJ, Cuchel M, D'Agostino RB, Davidson MH, Davidson WS, Heinecke JW, Karas RH, Kontush A, Krauss RM, Miller M, Rader DJ. High-density lipoproteins: A consensus statement from the National Lipid Association. J Clin Lipidol 2013; 7:484-525. [DOI: 10.1016/j.jacl.2013.08.001] [Citation(s) in RCA: 240] [Impact Index Per Article: 21.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2013] [Accepted: 08/03/2013] [Indexed: 12/21/2022]
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130
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Dávalos A, Fernández-Hernando C. From evolution to revolution: miRNAs as pharmacological targets for modulating cholesterol efflux and reverse cholesterol transport. Pharmacol Res 2013; 75:60-72. [PMID: 23435093 PMCID: PMC3825518 DOI: 10.1016/j.phrs.2013.02.005] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/05/2013] [Accepted: 02/11/2013] [Indexed: 02/09/2023]
Abstract
There has been strong evolutionary pressure to ensure that an animal cell maintains levels of cholesterol within tight limits for normal function. Imbalances in cellular cholesterol levels are a major player in the development of different pathologies associated to dietary excess. Although epidemiological studies indicate that elevated levels of high-density lipoprotein (HDL)-cholesterol reduce the risk of cardiovascular disease, recent genetic evidence and pharmacological therapies to raise HDL levels do not support their beneficial effects. Cholesterol efflux as the first and probably the most important step in reverse cholesterol transport is an important biological process relevant to HDL function. Small non-coding RNAs (microRNAs), post-transcriptional control different aspects of cellular cholesterol homeostasis including cholesterol efflux. miRNA families miR-33, miR-758, miR-10b, miR-26 and miR-106b directly modulates cholesterol efflux by targeting the ATP-binding cassette transporter A1 (ABCA1). Pre-clinical studies with anti-miR therapies to inhibit some of these miRNAs have increased cellular cholesterol efflux, reverse cholesterol transport and reduce pathologies associated to dyslipidemia. Although miRNAs as therapy have benefits from existing antisense technology, different obstacles need to be solved before we incorporate such research into clinical care. Here we focus on the clinical potential of miRNAs as therapeutic target to increase cholesterol efflux and reverse cholesterol transport as a new alternative to ameliorate cholesterol-related pathologies.
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131
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Godoy P, Hewitt NJ, Albrecht U, Andersen ME, Ansari N, Bhattacharya S, Bode JG, Bolleyn J, Borner C, Böttger J, Braeuning A, Budinsky RA, Burkhardt B, Cameron NR, Camussi G, Cho CS, Choi YJ, Craig Rowlands J, Dahmen U, Damm G, Dirsch O, Donato MT, Dong J, Dooley S, Drasdo D, Eakins R, Ferreira KS, Fonsato V, Fraczek J, Gebhardt R, Gibson A, Glanemann M, Goldring CEP, Gómez-Lechón MJ, Groothuis GMM, Gustavsson L, Guyot C, Hallifax D, Hammad S, Hayward A, Häussinger D, Hellerbrand C, Hewitt P, Hoehme S, Holzhütter HG, Houston JB, Hrach J, Ito K, Jaeschke H, Keitel V, Kelm JM, Kevin Park B, Kordes C, Kullak-Ublick GA, LeCluyse EL, Lu P, Luebke-Wheeler J, Lutz A, Maltman DJ, Matz-Soja M, McMullen P, Merfort I, Messner S, Meyer C, Mwinyi J, Naisbitt DJ, Nussler AK, Olinga P, Pampaloni F, Pi J, Pluta L, Przyborski SA, Ramachandran A, Rogiers V, Rowe C, Schelcher C, Schmich K, Schwarz M, Singh B, Stelzer EHK, Stieger B, Stöber R, Sugiyama Y, Tetta C, Thasler WE, Vanhaecke T, Vinken M, Weiss TS, Widera A, Woods CG, Xu JJ, Yarborough KM, Hengstler JG. Recent advances in 2D and 3D in vitro systems using primary hepatocytes, alternative hepatocyte sources and non-parenchymal liver cells and their use in investigating mechanisms of hepatotoxicity, cell signaling and ADME. Arch Toxicol 2013; 87:1315-530. [PMID: 23974980 PMCID: PMC3753504 DOI: 10.1007/s00204-013-1078-5] [Citation(s) in RCA: 1062] [Impact Index Per Article: 96.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2013] [Accepted: 05/06/2013] [Indexed: 12/15/2022]
Abstract
This review encompasses the most important advances in liver functions and hepatotoxicity and analyzes which mechanisms can be studied in vitro. In a complex architecture of nested, zonated lobules, the liver consists of approximately 80 % hepatocytes and 20 % non-parenchymal cells, the latter being involved in a secondary phase that may dramatically aggravate the initial damage. Hepatotoxicity, as well as hepatic metabolism, is controlled by a set of nuclear receptors (including PXR, CAR, HNF-4α, FXR, LXR, SHP, VDR and PPAR) and signaling pathways. When isolating liver cells, some pathways are activated, e.g., the RAS/MEK/ERK pathway, whereas others are silenced (e.g. HNF-4α), resulting in up- and downregulation of hundreds of genes. An understanding of these changes is crucial for a correct interpretation of in vitro data. The possibilities and limitations of the most useful liver in vitro systems are summarized, including three-dimensional culture techniques, co-cultures with non-parenchymal cells, hepatospheres, precision cut liver slices and the isolated perfused liver. Also discussed is how closely hepatoma, stem cell and iPS cell-derived hepatocyte-like-cells resemble real hepatocytes. Finally, a summary is given of the state of the art of liver in vitro and mathematical modeling systems that are currently used in the pharmaceutical industry with an emphasis on drug metabolism, prediction of clearance, drug interaction, transporter studies and hepatotoxicity. One key message is that despite our enthusiasm for in vitro systems, we must never lose sight of the in vivo situation. Although hepatocytes have been isolated for decades, the hunt for relevant alternative systems has only just begun.
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Affiliation(s)
- Patricio Godoy
- Leibniz Research Centre for Working Environment and Human Factors (IFADO), 44139 Dortmund, Germany
| | | | - Ute Albrecht
- Clinic for Gastroenterology, Hepatology and Infectious Diseases, Heinrich-Heine-University, Moorenstrasse 5, 40225 Düsseldorf, Germany
| | - Melvin E. Andersen
- The Hamner Institutes for Health Sciences, Research Triangle Park, NC USA
| | - Nariman Ansari
- Buchmann Institute for Molecular Life Sciences (BMLS), Goethe University Frankfurt, Max-von-Laue-Str. 15, 60438 Frankfurt am Main, Germany
| | - Sudin Bhattacharya
- The Hamner Institutes for Health Sciences, Research Triangle Park, NC USA
| | - Johannes Georg Bode
- Clinic for Gastroenterology, Hepatology and Infectious Diseases, Heinrich-Heine-University, Moorenstrasse 5, 40225 Düsseldorf, Germany
| | - Jennifer Bolleyn
- Department of Toxicology, Centre for Pharmaceutical Research, Faculty of Medicine and Pharmacy, Vrije Universiteit Brussel, 1090 Brussels, Belgium
| | - Christoph Borner
- Institute of Molecular Medicine and Cell Research, University of Freiburg, Freiburg, Germany
| | - Jan Böttger
- Institute of Biochemistry, Faculty of Medicine, University of Leipzig, 04103 Leipzig, Germany
| | - Albert Braeuning
- Department of Toxicology, Institute of Experimental and Clinical Pharmacology and Toxicology, Wilhelmstr. 56, 72074 Tübingen, Germany
| | - Robert A. Budinsky
- Toxicology and Environmental Research and Consulting, The Dow Chemical Company, Midland, MI USA
| | - Britta Burkhardt
- BG Trauma Center, Siegfried Weller Institut, Eberhard Karls University Tübingen, 72076 Tübingen, Germany
| | - Neil R. Cameron
- Department of Chemistry, Durham University, Durham, DH1 3LE UK
| | - Giovanni Camussi
- Department of Medical Sciences, University of Torino, 10126 Turin, Italy
| | - Chong-Su Cho
- Department of Agricultural Biotechnology and Research Institute for Agriculture and Life Sciences, Seoul National University, Seoul, 151-921 Korea
| | - Yun-Jaie Choi
- Department of Agricultural Biotechnology and Research Institute for Agriculture and Life Sciences, Seoul National University, Seoul, 151-921 Korea
| | - J. Craig Rowlands
- Toxicology and Environmental Research and Consulting, The Dow Chemical Company, Midland, MI USA
| | - Uta Dahmen
- Experimental Transplantation Surgery, Department of General Visceral, and Vascular Surgery, Friedrich-Schiller-University Jena, 07745 Jena, Germany
| | - Georg Damm
- Department of General-, Visceral- and Transplantation Surgery, Charité University Medicine Berlin, 13353 Berlin, Germany
| | - Olaf Dirsch
- Institute of Pathology, Friedrich-Schiller-University Jena, 07745 Jena, Germany
| | - María Teresa Donato
- Unidad de Hepatología Experimental, IIS Hospital La Fe Avda Campanar 21, 46009 Valencia, Spain
- CIBERehd, Fondo de Investigaciones Sanitarias, Barcelona, Spain
- Departamento de Bioquímica y Biología Molecular, Facultad de Medicina, Universidad de Valencia, Valencia, Spain
| | - Jian Dong
- The Hamner Institutes for Health Sciences, Research Triangle Park, NC USA
| | - Steven Dooley
- Department of Medicine II, Section Molecular Hepatology, Medical Faculty Mannheim, Heidelberg University, Mannheim, Germany
| | - Dirk Drasdo
- Interdisciplinary Center for Bioinformatics (IZBI), University of Leipzig, 04107 Leipzig, Germany
- INRIA (French National Institute for Research in Computer Science and Control), Domaine de Voluceau-Rocquencourt, B.P. 105, 78153 Le Chesnay Cedex, France
- UPMC University of Paris 06, CNRS UMR 7598, Laboratoire Jacques-Louis Lions, 4, pl. Jussieu, 75252 Paris cedex 05, France
| | - Rowena Eakins
- Department of Molecular and Clinical Pharmacology, Centre for Drug Safety Science, Institute of Translational Medicine, University of Liverpool, Liverpool, UK
| | - Karine Sá Ferreira
- Institute of Molecular Medicine and Cell Research, University of Freiburg, Freiburg, Germany
- GRK 1104 From Cells to Organs, Molecular Mechanisms of Organogenesis, Faculty of Biology, University of Freiburg, Freiburg, Germany
| | - Valentina Fonsato
- Department of Medical Sciences, University of Torino, 10126 Turin, Italy
| | - Joanna Fraczek
- Department of Toxicology, Centre for Pharmaceutical Research, Faculty of Medicine and Pharmacy, Vrije Universiteit Brussel, 1090 Brussels, Belgium
| | - Rolf Gebhardt
- Institute of Biochemistry, Faculty of Medicine, University of Leipzig, 04103 Leipzig, Germany
| | - Andrew Gibson
- Department of Molecular and Clinical Pharmacology, Centre for Drug Safety Science, Institute of Translational Medicine, University of Liverpool, Liverpool, UK
| | - Matthias Glanemann
- Department of General-, Visceral- and Transplantation Surgery, Charité University Medicine Berlin, 13353 Berlin, Germany
| | - Chris E. P. Goldring
- Department of Molecular and Clinical Pharmacology, Centre for Drug Safety Science, Institute of Translational Medicine, University of Liverpool, Liverpool, UK
| | - María José Gómez-Lechón
- Unidad de Hepatología Experimental, IIS Hospital La Fe Avda Campanar 21, 46009 Valencia, Spain
- CIBERehd, Fondo de Investigaciones Sanitarias, Barcelona, Spain
| | - Geny M. M. Groothuis
- Department of Pharmacy, Pharmacokinetics Toxicology and Targeting, University of Groningen, A. Deusinglaan 1, 9713 AV Groningen, The Netherlands
| | - Lena Gustavsson
- Department of Laboratory Medicine (Malmö), Center for Molecular Pathology, Lund University, Jan Waldenströms gata 59, 205 02 Malmö, Sweden
| | - Christelle Guyot
- Department of Clinical Pharmacology and Toxicology, University Hospital, 8091 Zurich, Switzerland
| | - David Hallifax
- Centre for Applied Pharmacokinetic Research (CAPKR), School of Pharmacy and Pharmaceutical Sciences, University of Manchester, Oxford Road, Manchester, M13 9PT UK
| | - Seddik Hammad
- Department of Forensic Medicine and Veterinary Toxicology, Faculty of Veterinary Medicine, South Valley University, Qena, Egypt
| | - Adam Hayward
- Biological and Biomedical Sciences, Durham University, Durham, DH13LE UK
| | - Dieter Häussinger
- Clinic for Gastroenterology, Hepatology and Infectious Diseases, Heinrich-Heine-University, Moorenstrasse 5, 40225 Düsseldorf, Germany
| | - Claus Hellerbrand
- Department of Medicine I, University Hospital Regensburg, 93053 Regensburg, Germany
| | | | - Stefan Hoehme
- Interdisciplinary Center for Bioinformatics (IZBI), University of Leipzig, 04107 Leipzig, Germany
| | - Hermann-Georg Holzhütter
- Institut für Biochemie Abteilung Mathematische Systembiochemie, Universitätsmedizin Berlin (Charité), Charitéplatz 1, 10117 Berlin, Germany
| | - J. Brian Houston
- Centre for Applied Pharmacokinetic Research (CAPKR), School of Pharmacy and Pharmaceutical Sciences, University of Manchester, Oxford Road, Manchester, M13 9PT UK
| | | | - Kiyomi Ito
- Research Institute of Pharmaceutical Sciences, Musashino University, 1-1-20 Shinmachi, Nishitokyo-shi, Tokyo, 202-8585 Japan
| | - Hartmut Jaeschke
- Department of Pharmacology, Toxicology and Therapeutics, University of Kansas Medical Center, Kansas City, KS 66160 USA
| | - Verena Keitel
- Clinic for Gastroenterology, Hepatology and Infectious Diseases, Heinrich-Heine-University, Moorenstrasse 5, 40225 Düsseldorf, Germany
| | | | - B. Kevin Park
- Department of Molecular and Clinical Pharmacology, Centre for Drug Safety Science, Institute of Translational Medicine, University of Liverpool, Liverpool, UK
| | - Claus Kordes
- Clinic for Gastroenterology, Hepatology and Infectious Diseases, Heinrich-Heine-University, Moorenstrasse 5, 40225 Düsseldorf, Germany
| | - Gerd A. Kullak-Ublick
- Department of Clinical Pharmacology and Toxicology, University Hospital, 8091 Zurich, Switzerland
| | - Edward L. LeCluyse
- The Hamner Institutes for Health Sciences, Research Triangle Park, NC USA
| | - Peng Lu
- The Hamner Institutes for Health Sciences, Research Triangle Park, NC USA
| | | | - Anna Lutz
- Department of Pharmaceutical Biology and Biotechnology, University of Freiburg, Freiburg, Germany
| | - Daniel J. Maltman
- Reinnervate Limited, NETPark Incubator, Thomas Wright Way, Sedgefield, TS21 3FD UK
| | - Madlen Matz-Soja
- Institute of Biochemistry, Faculty of Medicine, University of Leipzig, 04103 Leipzig, Germany
| | - Patrick McMullen
- The Hamner Institutes for Health Sciences, Research Triangle Park, NC USA
| | - Irmgard Merfort
- Department of Pharmaceutical Biology and Biotechnology, University of Freiburg, Freiburg, Germany
| | | | - Christoph Meyer
- Department of Medicine II, Section Molecular Hepatology, Medical Faculty Mannheim, Heidelberg University, Mannheim, Germany
| | - Jessica Mwinyi
- Department of Clinical Pharmacology and Toxicology, University Hospital, 8091 Zurich, Switzerland
| | - Dean J. Naisbitt
- Department of Molecular and Clinical Pharmacology, Centre for Drug Safety Science, Institute of Translational Medicine, University of Liverpool, Liverpool, UK
| | - Andreas K. Nussler
- BG Trauma Center, Siegfried Weller Institut, Eberhard Karls University Tübingen, 72076 Tübingen, Germany
| | - Peter Olinga
- Division of Pharmaceutical Technology and Biopharmacy, Department of Pharmacy, University of Groningen, 9713 AV Groningen, The Netherlands
| | - Francesco Pampaloni
- Buchmann Institute for Molecular Life Sciences (BMLS), Goethe University Frankfurt, Max-von-Laue-Str. 15, 60438 Frankfurt am Main, Germany
| | - Jingbo Pi
- The Hamner Institutes for Health Sciences, Research Triangle Park, NC USA
| | - Linda Pluta
- The Hamner Institutes for Health Sciences, Research Triangle Park, NC USA
| | - Stefan A. Przyborski
- Reinnervate Limited, NETPark Incubator, Thomas Wright Way, Sedgefield, TS21 3FD UK
- Biological and Biomedical Sciences, Durham University, Durham, DH13LE UK
| | - Anup Ramachandran
- Department of Pharmacology, Toxicology and Therapeutics, University of Kansas Medical Center, Kansas City, KS 66160 USA
| | - Vera Rogiers
- Department of Toxicology, Centre for Pharmaceutical Research, Faculty of Medicine and Pharmacy, Vrije Universiteit Brussel, 1090 Brussels, Belgium
| | - Cliff Rowe
- Department of Molecular and Clinical Pharmacology, Centre for Drug Safety Science, Institute of Translational Medicine, University of Liverpool, Liverpool, UK
| | - Celine Schelcher
- Department of Surgery, Liver Regeneration, Core Facility, Human in Vitro Models of the Liver, Ludwig Maximilians University of Munich, Munich, Germany
| | - Kathrin Schmich
- Department of Pharmaceutical Biology and Biotechnology, University of Freiburg, Freiburg, Germany
| | - Michael Schwarz
- Department of Toxicology, Institute of Experimental and Clinical Pharmacology and Toxicology, Wilhelmstr. 56, 72074 Tübingen, Germany
| | - Bijay Singh
- Department of Agricultural Biotechnology and Research Institute for Agriculture and Life Sciences, Seoul National University, Seoul, 151-921 Korea
| | - Ernst H. K. Stelzer
- Buchmann Institute for Molecular Life Sciences (BMLS), Goethe University Frankfurt, Max-von-Laue-Str. 15, 60438 Frankfurt am Main, Germany
| | - Bruno Stieger
- Department of Clinical Pharmacology and Toxicology, University Hospital, 8091 Zurich, Switzerland
| | - Regina Stöber
- Leibniz Research Centre for Working Environment and Human Factors (IFADO), 44139 Dortmund, Germany
| | - Yuichi Sugiyama
- Sugiyama Laboratory, RIKEN Innovation Center, RIKEN, Yokohama Biopharmaceutical R&D Center, 1-7-22 Suehiro-cho, Tsurumi-ku, Yokohama, Kanagawa 230-0045 Japan
| | - Ciro Tetta
- Fresenius Medical Care, Bad Homburg, Germany
| | - Wolfgang E. Thasler
- Department of Surgery, Ludwig-Maximilians-University of Munich Hospital Grosshadern, Munich, Germany
| | - Tamara Vanhaecke
- Department of Toxicology, Centre for Pharmaceutical Research, Faculty of Medicine and Pharmacy, Vrije Universiteit Brussel, 1090 Brussels, Belgium
| | - Mathieu Vinken
- Department of Toxicology, Centre for Pharmaceutical Research, Faculty of Medicine and Pharmacy, Vrije Universiteit Brussel, 1090 Brussels, Belgium
| | - Thomas S. Weiss
- Department of Pediatrics and Juvenile Medicine, University of Regensburg Hospital, Regensburg, Germany
| | - Agata Widera
- Leibniz Research Centre for Working Environment and Human Factors (IFADO), 44139 Dortmund, Germany
| | - Courtney G. Woods
- The Hamner Institutes for Health Sciences, Research Triangle Park, NC USA
| | | | | | - Jan G. Hengstler
- Leibniz Research Centre for Working Environment and Human Factors (IFADO), 44139 Dortmund, Germany
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Loren J, Huang Z, Laffitte BA, Molteni V. Liver X receptor modulators: a review of recently patented compounds (2009 - 2012). Expert Opin Ther Pat 2013; 23:1317-35. [PMID: 23826715 DOI: 10.1517/13543776.2013.814640] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
INTRODUCTION The development of small molecule agonists of the liver X receptors (LXRs) has been an area of interest for over a decade, given the critical role of those receptors in cholesterol metabolism, glucose homeostasis, inflammation, innate immunity and lipogenesis. Many potential indications have been characterized over time including atherosclerosis, diabetes, inflammation, Alzheimer's disease and cancer. However, concerns about the lipogenic effects of full LXRα/β agonists have required extensive efforts aimed at identifying LXRβ agonist with limited activity on the LXRα receptor to increase the safety margins. AREAS COVERED This review includes a summary of the LXR agonists that have reached the clinic and summarizes the patent applications for LXR modulators from September 2009 to December 2012 with emphasis on chemical matters, biological data associated with selected analogs and therapeutic indications. EXPERT OPINION As LXR agonists have the potential to be useful for many indications, the scientific community, despite setbacks due to on-target side effects, has maintained interest and devised strategies to overcome safety hurdles. While a clinical proof of concept still remains elusive, the recent advancement of compounds into the clinic highlights that acceptable safety margins in preclinical species have been achieved.
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Affiliation(s)
- Jon Loren
- Genomics Institute of the Novartis Research Foundation , 10675 John Jay Hopkins Drive, San Diego, CA 92121 , USA +001 858 332 4736 ;
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133
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Ishibashi M, Filomenko R, Rébé C, Chevriaux A, Varin A, Derangère V, Bessède G, Gambert P, Lagrost L, Masson D. Knock-down of the oxysterol receptor LXRα impairs cholesterol efflux in human primary macrophages: Lack of compensation by LXRβ activation. Biochem Pharmacol 2013; 86:122-9. [DOI: 10.1016/j.bcp.2012.12.024] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2012] [Revised: 12/20/2012] [Accepted: 12/21/2012] [Indexed: 11/24/2022]
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134
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Xue J, Wang C, Zhu C, Li Y. ATP-binding cassette transporter G1 protects against endothelial dysfunction induced by high glucose. Diabetes Res Clin Pract 2013; 101:72-80. [PMID: 23693076 DOI: 10.1016/j.diabres.2013.04.009] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/01/2013] [Revised: 03/28/2013] [Accepted: 04/25/2013] [Indexed: 01/22/2023]
Abstract
AIMS ATP binding cassette transporter G1 (ABCG1), a regulator of cholesterol efflux to HDL, has been shown to decrease in macrophages and smooth muscle cells under high glucose conditions. Endothelial cells have a high capacity to efflux sterols and express ABCG1. In the present study we explored the role of ABCG1 in high glucose-induced endothelial dysfunction. METHODS Human aortic endothelial cells (HAECs) were cultured under high glucose conditions. ABCG1 mRNA and protein expression in HAECs were measured by real time PCR and Western blot. Cholesterol efflux and NO synthesis (NOS) activity were determined by means of scintillation counting. Total intracellular cholesterol was determined by gas-liquid chromatography. The secretion of IL-6 and ICAM-1 was measured using ELISA. The generation of intracellular reactive oxygen species (ROS) was measured using a fluorescence microscope. RESULTS We observed that high glucose suppressed ABCG1 expression and intracellular cholesterol efflux to HDL. Furthermore, high glucose increased the secretion of IL-6 and ICAM, as well as decreased phospho-eNOS protein expression and NOS activity. These processes were reversed by the up-regulation of ABCG1 using the liver X receptor (LXR) agonist T0901307 and an ABCG1 expression vector. In addition, high glucose-induced oxidative stress was reduced by the upregulation of ABCG1. In contrast, knock-down of ABCG1 in HAECs significantly increased the secretion of IL-6 and ICAM, as well as decreased phospho-eNOS protein expression and NOS activity. CONCLUSIONS The present results suggest that ABCG1 plays an important role in protecting against endothelial dysfunction induced by high glucose.
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Affiliation(s)
- Jiahong Xue
- Department of Cardiovascular Medicine, Second Affiliated Hospital of Medical School, Xi'an Jiaotong University, Xi'an, Shaanxi 710004, China.
| | - Congxia Wang
- Department of Cardiovascular Medicine, Second Affiliated Hospital of Medical School, Xi'an Jiaotong University, Xi'an, Shaanxi 710004, China
| | - Canzhan Zhu
- Department of Cardiovascular Medicine, Second Affiliated Hospital of Medical School, Xi'an Jiaotong University, Xi'an, Shaanxi 710004, China
| | - Yongqin Li
- Department of Cardiovascular Medicine, Second Affiliated Hospital of Medical School, Xi'an Jiaotong University, Xi'an, Shaanxi 710004, China
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Bi X, Zhu X, Duong M, Boudyguina EY, Wilson MD, Gebre AK, Parks JS. Liver ABCA1 deletion in LDLrKO mice does not impair macrophage reverse cholesterol transport or exacerbate atherogenesis. Arterioscler Thromb Vasc Biol 2013; 33:2288-96. [PMID: 23814116 DOI: 10.1161/atvbaha.112.301110] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
OBJECTIVE Hepatic ATP binding cassette transporter A1 (ABCA1) expression is critical for maintaining plasma high-density lipoprotein (HDL) concentrations, but its role in macrophage reverse cholesterol transport and atherosclerosis is not fully understood. We investigated atherosclerosis development and reverse cholesterol transport in hepatocyte-specific ABCA1 knockout (HSKO) mice in the low-density lipoprotein (LDL) receptor KO (LDLrKO) C57BL/6 background. APPROACH AND RESULTS Male and female LDLrKO and HSKO/LDLrKO mice were switched from chow at 8 weeks of age to an atherogenic diet (10% palm oil, 0.2% cholesterol) for 16 weeks. Chow-fed HSKO/LDLrKO mice had HDL concentrations 10% to 20% of LDLrKO mice, but similar very low-density lipoprotein and LDL concentrations. Surprisingly, HSKO/LDLrKO mice fed the atherogenic diet had significantly lower (40% to 60%) very low-density lipoprotein, LDL, and HDL concentrations (50%) compared with LDLrKO mice. Aortic surface lesion area and cholesterol content were similar for both genotypes of mice, but aortic root intimal area was significantly lower (20% to 40%) in HSKO/LDLrKO mice. Although macrophage (3)H-cholesterol efflux to apoB lipoprotein-depleted plasma was 24% lower for atherogenic diet-fed HSKO/LDLrKO versus LDLrKO mice, variation in percentage efflux among individual mice was <2-fold compared with a 10-fold variation in plasma HDL concentrations, suggesting that HDL levels, per se, were not the primary determinant of plasma efflux capacity. In vivo reverse cholesterol transport, resident peritoneal macrophage sterol content, biliary lipid composition, and fecal cholesterol mass were similar between both genotypes of mice. CONCLUSIONS The markedly reduced plasma HDL pool in HSKO/LDLrKO mice is sufficient to maintain macrophage reverse cholesterol transport, which, along with reduced plasma very low-density lipoprotein and LDL concentrations, prevented the expected increase in atherosclerosis.
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Affiliation(s)
- Xin Bi
- From the Section on Lipid Sciences, Department of Pathology (X.B., X.Z., M.D., E.Y.B., M.D.W., A.K.G., J.S.P.), and Department of Biochemistry (J.S.P.), Wake Forest School of Medicine, Winston-Salem, NC
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Niacin Reduces Atherosclerosis Development in APOE*3Leiden.CETP Mice Mainly by Reducing NonHDL-Cholesterol. PLoS One 2013; 8:e66467. [PMID: 23840481 PMCID: PMC3686722 DOI: 10.1371/journal.pone.0066467] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2013] [Accepted: 05/06/2013] [Indexed: 12/29/2022] Open
Abstract
Objective Niacin potently lowers triglycerides, mildly decreases LDL-cholesterol, and largely increases HDL-cholesterol. Despite evidence for an atheroprotective effect of niacin from previous small clinical studies, the large outcome trials, AIM-HIGH and HPS2-THRIVE did not reveal additional beneficial effects of niacin (alone or in combination with laropiprant) on top of statin treatment. We aimed to address this apparent discrepancy by investigating the effects of niacin without and with simvastatin on atherosclerosis development and determine the underlying mechanisms, in APOE*3Leiden.CETP mice, a model for familial dysbetalipoproteinemia (FD). Approach and Results Mice were fed a western-type diet containing cholesterol without or with niacin (120 mg/kg/day), simvastatin (36 mg/kg/day) or their combination for 18 weeks. Similarly as in FD patients, niacin reduced total cholesterol by -39% and triglycerides by −50%, (both P<0.001). Simvastatin and the combination reduced total cholesterol (−30%; −55%, P<0.001) where the combination revealed a greater reduction compared to simvastatin (−36%, P<0.001). Niacin decreased total cholesterol and triglycerides primarily by increasing VLDL clearance. Niacin increased HDL-cholesterol (+28%, P<0.01) and mildly increased reverse cholesterol transport. All treatments reduced monocyte adhesion to the endothelium (−46%; −47%, P<0.01; −53%, P<0.001), atherosclerotic lesion area (−78%; −49%, P<0.01; −87%, P<0.001) and severity. Compared to simvastatin, the combination increased plaque stability index [(SMC+collagen)/macrophages] (3-fold, P<0.01). Niacin and the combination reduced T cells in the aortic root (−71%, P<0.01; −81%, P<0.001). Lesion area was strongly predicted by nonHDL-cholesterol (R2 = 0.69, P<0.001) and to a much lesser extent by HDL-cholesterol (R2 = 0.20, P<0.001). Conclusion Niacin decreases atherosclerosis development mainly by reducing nonHDL-cholesterol with modest HDL-cholesterol-raising and additional anti-inflammatory effects. The additive effect of niacin on top of simvastatin is mostly dependent on its nonHDL-cholesterol-lowering capacities. These data suggest that clinical beneficial effects of niacin are largely dependent on its ability to lower LDL-cholesterol on top of concomitant lipid-lowering therapy.
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Steffensen KR, Jakobsson T, Gustafsson JÅ. Targeting liver X receptors in inflammation. Expert Opin Ther Targets 2013; 17:977-90. [PMID: 23738533 DOI: 10.1517/14728222.2013.806490] [Citation(s) in RCA: 49] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
INTRODUCTION The two oxysterol receptors, 'liver X receptors (LXRs)' LXRα and LXRβ, are amongst the emerging newer drug targets within the nuclear receptor family and targeting LXRs represents novel strategies needed for prevention and treatment of diseases where current therapeutics is inadequate. AREAS COVERED This review discusses the current understanding of LXR biology with an emphasis on the molecular aspects of LXR signalling establishing their potential as drug targets. Recent advances of their transcriptional mechanisms in inflammatory pathways and their physiological roles in inflammation and immunity are described. EXPERT OPINION The new discoveries of LXR-regulated inflammatory pathways have ignited new promises for LXRs as drug targets. The broad physiological roles of LXRs involve a high risk of unwanted side effects. Recent insights into LXR biology of the brain indicate a highly important role in neuronal development and a clinical trial testing an LXR agonist reported adverse neurological side effects. This suggests that drug development must focus on limiting the range of LXR signalling - possibly achieved through subtype, tissue specific, promoter specific or pathway specific activation of LXRs where a successful candidate drug must be carefully studied for its effect in the central nervous system.
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Affiliation(s)
- Knut R Steffensen
- Karolinska Institutet, Center for Biosciences, Department of Biosciences and Nutrition, S-14183 Stockholm, Sweden.
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138
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Zhang L, Jiang M, Shui Y, Chen Y, Wang Q, Hu W, Ma X, Li X, Liu X, Cao X, Liu M, Duan Y, Han J. DNA topoisomerase II inhibitors induce macrophage ABCA1 expression and cholesterol efflux—An LXR-dependent mechanism. Biochim Biophys Acta Mol Cell Biol Lipids 2013; 1831:1134-45. [DOI: 10.1016/j.bbalip.2013.02.007] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2012] [Revised: 01/27/2013] [Accepted: 02/22/2013] [Indexed: 10/27/2022]
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Raksaseri P, Chatsudthipong V, Muanprasat C, Soodvilai S. Activation of liver X receptors reduces CFTR-mediated Cl(-) transport in kidney collecting duct cells. Am J Physiol Renal Physiol 2013; 305:F583-91. [PMID: 23720350 DOI: 10.1152/ajprenal.00579.2012] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
Liver X receptors (LXRs) are transcription factors belonging to the nuclear receptor super family, which act as regulators of lipid and glucose metabolism. However, LXRs have been shown to regulate the function of transporters in the kidney, including the Na-Pi cotransporter, organic anion transporter, and epithelial Na(+) channel. In this report, we demonstrated the ability of LXR ligands, both endogenous [22 (R)-hydroxycholesterol] and synthetic (T0901317 and GW3965), to reduce CFTR-mediated Cl(-) secretion in a type I Madin-Darby canine kidney (MDCK) cell line and in murine primary inner medullary collecting duct (IMCD) cells, based on measurements of [Arg(8)]-vasopressin-induced Cl(-) current. However, treatment of MDCK cell monolayers with 5 μM T0901317 for 24 h did not alter ouabain-senstive current or Na(+)-K(+)-ATPase-α protein content. Furthermore, basolateral membranes permeabilization of MDCK cell monolayers still resulted in a decrease in apical Cl(-) current stimulated by both [Arg(8)]-vasopressin and 8-cholorophenyl-thio-cAMP, indicating that the factor(s) encoded by the target gene(s) of agonist-activated LXRs might be located at the apical membrane. Western blot analysis revealed that inhibition of Cl(-) secretion occurred via a decrease in CFTR protein, which was not due to downregulation of its mRNA expression. In addition, both synthetic LXR agonists significantly retarded the growth of forskolin-induced cysts formed in MDCK cells cultured in collagen gel. This is the first evidence showing that ligand-activated LXRs are capable of downregulating CFTR-mediated Cl(-) secretion of kidney cells and of retarding cyst growth in a MDCK cell model.
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Affiliation(s)
- Promporn Raksaseri
- Dept. of Physiology, Faculty of Science, Mahidol Univ., Rama VI Road, Bangkok 10400, Thailand.
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Newer therapeutic strategies to alter high-density lipoprotein level and function. Cardiol Rev 2013; 22:17-24. [PMID: 23707991 DOI: 10.1097/crd.0b013e31829cac29] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
Measurements of low levels of high-density lipoprotein (HDL) cholesterol have been identified as a risk factor for premature coronary artery disease, however, to date, current pharmacologic approaches for raising HDL have provided little benefit, if at all, in reducing cardiovascular outcomes. It has been shown that HDL can modify many aspects of plaque pathogenesis. Its most established role is in reverse cholesterol transportation, but HDL can also affect oxidation, inflammation, cellular adhesion, and vasodilatation. Considering these potential benefits of HDL, newer treatments have been developed to modify HDL activity, which include the use of oral cholesteryl ester transfer protein inhibitors, apolipoprotein (apo)A-I infusions, apoA-I mimetics, drugs to increase apoA-I synthesis, and agonists of the liver X receptor. These new therapies are reviewed in this article.
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The role of the gut in reverse cholesterol transport--focus on the enterocyte. Prog Lipid Res 2013; 52:317-28. [PMID: 23608233 DOI: 10.1016/j.plipres.2013.04.003] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2013] [Revised: 03/01/2013] [Accepted: 04/10/2013] [Indexed: 11/20/2022]
Abstract
In the arterial intima, macrophages become cholesterol-enriched foam cells and atherosclerotic lesions are generated. This atherogenic process can be attenuated, prevented, or even reversed by HDL particles capable of initiating a multistep pathway known as the macrophage-specific reverse cholesterol transport. The macrophage-derived cholesterol released to HDL is taken up by the liver, secreted into the bile, and ultimately excreted in the feces. Importantly, the absorptive epithelial cells lining the lumen of the small intestine, the enterocytes, express several membrane-associated proteins which mediate the influx of luminal cholesterol and its subsequent efflux at their apical and basolateral sides. Moreover, generation of intestinal HDL and systemic effects of the gut microbiota recently revealed a direct link between the gut and the cholesterol cargo of peripheral macrophages. This review summarizes experimental evidence establishing that the reverse cholesterol transport pathway which initiates in macrophages is susceptible to modulation in the small intestine. We also describe four paths which govern cholesterol passage across the enterocyte and define a role for the gut in the regulation of reverse cholesterol transport. Understanding the concerted function of these paths may be useful when designing therapeutic strategies aimed at removing cholesterol from the foam cells which occupy atherosclerotic lesions.
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Westerterp M, Murphy AJ, Wang M, Pagler TA, Vengrenyuk Y, Kappus MS, Gorman DJ, Nagareddy PR, Zhu X, Abramowicz S, Parks JS, Welch C, Fisher EA, Wang N, Yvan-Charvet L, Tall AR. Deficiency of ATP-binding cassette transporters A1 and G1 in macrophages increases inflammation and accelerates atherosclerosis in mice. Circ Res 2013; 112:1456-65. [PMID: 23572498 DOI: 10.1161/circresaha.113.301086] [Citation(s) in RCA: 227] [Impact Index Per Article: 20.6] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
RATIONALE Plasma high-density lipoprotein levels are inversely correlated with atherosclerosis. Although it is widely assumed that this is attributable to the ability of high-density lipoprotein to promote cholesterol efflux from macrophage foam cells, direct experimental support for this hypothesis is lacking. OBJECTIVE To assess the role of macrophage cholesterol efflux pathways in atherogenesis. METHODS AND RESULTS We developed mice with efficient deletion of the ATP-binding cassette transporters A1 and G1 (ABCA1 and ABCG1) in macrophages (MAC-ABC(DKO) mice) but not in hematopoietic stem or progenitor populations. MAC-ABC(DKO) bone marrow (BM) was transplanted into Ldlr(-/-) recipients. On the chow diet, these mice had similar plasma cholesterol and blood monocyte levels but increased atherosclerosis compared with controls. On the Western-type diet, MAC-ABC(DKO) BM-transplanted Ldlr(-/-) mice had disproportionate atherosclerosis, considering they also had lower very low-density lipoprotein/low-density lipoprotein cholesterol levels than controls. ABCA1/G1-deficient macrophages in lesions showed increased inflammatory gene expression. Unexpectedly, Western-type diet-fed MAC-ABC(DKO) BM-transplanted Ldlr(-/-) mice displayed monocytosis and neutrophilia in the absence of hematopoietic stem and multipotential progenitor cells proliferation. Mechanistic studies revealed increased expressions of machrophage colony stimulating factor and granulocyte colony stimulating factor in splenic macrophage foam cells, driving BM monocyte and neutrophil production. CONCLUSIONS These studies show that macrophage deficiency of ABCA1/G1 is proatherogenic likely by promoting plaque inflammation and uncover a novel positive feedback loop in which cholesterol-laden splenic macrophages signal BM progenitors to produce monocytes, with suppression by macrophage cholesterol efflux pathways.
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Affiliation(s)
- Marit Westerterp
- Division of Molecular Medicine, Department of Medicine, Columbia University, New York, NY 10032, USA.
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Abstract
Reverse cholesterol transport (RCT) is the pathway by which cholesterol accumulated in peripheral tissues, including the artery wall, is transported to the liver for excretion. There is strong evidence suggesting that interventions that increase macrophage cholesterol efflux and RCT would be antiatherogenic. In this issue of the JCI, Martel et al. investigate the contribution of lymphatic vasculature to RCT. Their results support the concept that the lymphatic vessel route is critical for RCT from atherosclerotic plaques. Therefore, strategies to improve lymphatic transport might be useful for treating atherosclerotic vascular disease.
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Affiliation(s)
- Carlos Fernández-Hernando
- Department of Medicine, Leon H. Charney Division of Cardiology and the Marc and Ruti Bell Vascular Biology and Disease Program, New York University School of Medicine, New York, New York, USA.
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Griffett K, Solt LA, El-Gendy BEDM, Kamenecka TM, Burris TP. A liver-selective LXR inverse agonist that suppresses hepatic steatosis. ACS Chem Biol 2013; 8:559-67. [PMID: 23237488 DOI: 10.1021/cb300541g] [Citation(s) in RCA: 89] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
Fatty liver, which often accompanies obesity and type 2 diabetes, frequently leads to a much more debilitating hepatic disease including non-alcoholic steatohepatitis, cirrhosis, and hepatocellular carcinoma. Current pharmacological therapies lack conclusive efficacy and thus treatment options are limited. Novel therapeutics that suppress either hepatic lipogenesis and/or hepatic inflammation may be useful. Here, we describe the development of the first selective synthetic LXR inverse agonist (SR9238) and demonstrate that this compound effectively suppresses hepatic lipogenesis, inflammation, and hepatic lipid accumulation in a mouse model of non-alcoholic hepatosteatosis. SR9238 displays high potency for both LXRα and LXRβ (40-200 nM IC50) and was designed to display liver specificity so as to avoid potential side effects due to suppression of LXR in the periphery. Unexpectedly, treatment of diet-induced obese mice with SR9238 suppressed plasma cholesterol levels. These data indicate that liver-selective LXR inverse agonists may hold utility in the treatment of liver disease.
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Affiliation(s)
- Kristine Griffett
- The Scripps Research Institute, Jupiter, Florida 33458,
United States
| | - Laura A. Solt
- The Scripps Research Institute, Jupiter, Florida 33458,
United States
| | | | | | - Thomas P. Burris
- The Scripps Research Institute, Jupiter, Florida 33458,
United States
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Bonamassa B, Moschetta A. Atherosclerosis: lessons from LXR and the intestine. Trends Endocrinol Metab 2013; 24:120-8. [PMID: 23158108 DOI: 10.1016/j.tem.2012.10.004] [Citation(s) in RCA: 50] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/27/2012] [Revised: 10/12/2012] [Accepted: 10/18/2012] [Indexed: 12/17/2022]
Abstract
Modulation of the cholesterol-sensing liver X receptors (LXRs) and their downstream targets has emerged as promising therapeutic avenues in atherosclerosis. The intestine is important for its unique capabilities to act as a gatekeeper for cholesterol absorption and to participate in the process of cholesterol elimination in the feces and reverse cholesterol transport (RCT). Pharmacological and genetic intestine-specific LXR activation have been shown to protect against atherosclerosis. In this review we discuss the LXR-targeted molecular players in the enterocytes as well as the intestine-driven pathways contributing to cholesterol homeostasis with therapeutic potential as targets in the prevention and treatment of atherosclerosis..
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Affiliation(s)
- Barbara Bonamassa
- Laboratory of Lipid Metabolism and Cancer, Department of Translational Pharmacology, Consorzio Mario Negri Sud, Via Nazionale 8/A, 66030 Santa Maria Imbaro (CH), Italy
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Cortes VA, Busso D, Mardones P, Maiz A, Arteaga A, Nervi F, Rigotti A. Retracted: Advances in the physiological and pathological implications of cholesterol. Biol Rev Camb Philos Soc 2013; 88:825-43. [DOI: 10.1111/brv.12025] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2012] [Revised: 01/22/2013] [Accepted: 01/25/2013] [Indexed: 01/07/2023]
Affiliation(s)
- Victor A. Cortes
- Department of Nutrition Diabetes and Metabolism; School of Medicine; Faculty of Medicine; Pontificia Universidad Catolica de Chile; Marcoleta 367 Edifico de Gastroenterologia 4 piso Santiago Chile
| | - Dolores Busso
- Department of Nutrition Diabetes and Metabolism; School of Medicine; Faculty of Medicine; Pontificia Universidad Catolica de Chile; Marcoleta 367 Edifico de Gastroenterologia 4 piso Santiago Chile
| | - Pablo Mardones
- Department of Nutrition Diabetes and Metabolism; School of Medicine; Faculty of Medicine; Pontificia Universidad Catolica de Chile; Marcoleta 367 Edifico de Gastroenterologia 4 piso Santiago Chile
| | - Alberto Maiz
- Department of Nutrition Diabetes and Metabolism; School of Medicine; Faculty of Medicine; Pontificia Universidad Catolica de Chile; Marcoleta 367 Edifico de Gastroenterologia 4 piso Santiago Chile
| | - Antonio Arteaga
- Department of Nutrition Diabetes and Metabolism; School of Medicine; Faculty of Medicine; Pontificia Universidad Catolica de Chile; Marcoleta 367 Edifico de Gastroenterologia 4 piso Santiago Chile
| | - Flavio Nervi
- Department of Gastroenterology; School of Medicine; Faculty of Medicine; Pontificia Universidad Catolica de Chile; Santiago Chile
| | - Attilio Rigotti
- Department of Nutrition Diabetes and Metabolism; School of Medicine; Faculty of Medicine; Pontificia Universidad Catolica de Chile; Marcoleta 367 Edifico de Gastroenterologia 4 piso Santiago Chile
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Kasim S, Moran D, McFadden E. Vulnerable plaque: from bench to bedside; local pacification versus systemic therapy. Heart Views 2013; 13:139-45. [PMID: 23439781 PMCID: PMC3573359 DOI: 10.4103/1995-705x.105731] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023] Open
Abstract
Critical coronary stenoses accounts for a small proportion of acute coronary syndromes and sudden death. The majority are caused by coronary thromboses that arise from a nonangiographically obstructive atheroma. Recent developments in noninvasive imaging of so-called vulnerable plaques created opportunities to direct treatment to prevent morbidity and mortality associated with these high-risk lesions. This review covers therapy employed in the past, present, and potentially in the future as the natural history of plaque assessment unfolds.
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Affiliation(s)
- Sazzli Kasim
- Cardiology Unit, Medical Faculty, UiTM Sg Buloh, Selangor, Malaysia ; Division of Cardiology, Cork University Hospital, Cork, Ireland
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Regression of inflammation in atherosclerosis by the LXR agonist R211945: a noninvasive assessment and comparison with atorvastatin. JACC Cardiovasc Imaging 2013; 5:819-28. [PMID: 22897996 DOI: 10.1016/j.jcmg.2011.11.025] [Citation(s) in RCA: 63] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/15/2011] [Revised: 10/13/2011] [Accepted: 11/30/2011] [Indexed: 11/23/2022]
Abstract
OBJECTIVES The aim of this study was to noninvasively detect the anti-inflammatory properties of the novel liver X receptor agonist R211945. BACKGROUND R211945 induces reversal cholesterol transport and modulates inflammation in atherosclerotic plaques. We aimed to characterize with (18)F-fluorodeoxyglucose (FDG)-positron emission tomography (PET)/computed tomography (CT) and dynamic contrast-enhanced cardiac magnetic resonance (DCE-CMR) inflammation and neovascularization, respectively, in atherosclerotic plaques with R211945 treatment compared with atorvastatin treatment and a control. METHODS Twenty-one atherosclerotic New Zealand white rabbits were divided into 3 groups (control, R211945 [3 mg/kg orally], and atorvastatin [3 mg/kg orally] groups). All groups underwent (18)F-FDG-PET/CT and DCE-CMR at baseline and at 1 and 3 months after treatment initiation. Concomitantly, serum metabolic parameters and histology were assessed. For statistical analysis, continuous DCE-CMR and PET/CT outcomes were modeled as linear functions of time by using a linear mixed model, whereas the histological data, animal characteristics data, and nonlinear regression imaging data were analyzed with a 2-tailed Student t test. RESULTS (18)F-FDG-PET/CT detected a decrease in mean and maximum standard uptake values (SUV) over time in the R211945 group (both p = 0.001), indicating inflammation regression. The atorvastatin group displayed no significant change (p = 0.371 and p = 0.600, respectively), indicating no progression or regression. The control group demonstrated an increase in SUV (p = 0.01 and p = 0.04, respectively), indicating progression. There was a significant interaction between time and group for mean and maximum SUV (p = 0.0003 and p = 0.0016, respectively) . DCE-CMR detected a trend toward difference (p = 0.06) in the area under the curve in the atorvastatin group, suggesting a decrease in neovascularization. There was no significant interaction between time and group (p = 0.6350 and p = 0.8011, respectively). Macrophage and apolipoprotein B immunoreactivity decreased in the R211945 and atorvastatin groups (p < 0.0001 and p = 0.0004, respectively), and R211945 decreased oxidized phospholipid immunoreactivity (p = 0.02). CONCLUSIONS Noninvasive imaging with (18)F-FDG-PET/CT and DCE-CMR and histological analysis demonstrated significant anti-inflammatory effects of the LXR agonist R211945 compared with atorvastatin. The results suggest a possible role for LXR agonists in the treatment of atherosclerosis.
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Escolà-Gil JC, Julve J, Llaverias G, Urpi-Sarda M, Silvennoinen R, Lee-Rueckert M, Andres-Lacueva C, Blanco-Vaca F. Resveratrol administration or SIRT1 overexpression does not increase LXR signaling and macrophage-to-feces reverse cholesterol transport in vivo. Transl Res 2013; 161:110-7. [PMID: 23146569 DOI: 10.1016/j.trsl.2012.10.008] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/04/2012] [Revised: 10/16/2012] [Accepted: 10/19/2012] [Indexed: 01/24/2023]
Abstract
The natural polyphenol resveratrol has cardiometabolic protective properties. Resveratrol has been reported to be an activator of NAD+-dependent deacetylase sirtuin 1 (SIRT1), which may regulate liver X receptor (LXR) activity, thereby upregulating the expression of genes crucial in reverse cholesterol transport (RCT). In the present study, the effects of resveratrol and SIRT1 overexpression on RCT from macrophages-to-feces in vivo in C57BL/6 mice were determined. [³H]cholesterol-labeled mouse macrophages were injected intraperitoneally into mice treated with intragastric doses of the well-known LXR agonist T0901317, resveratrol, or a vehicle solution, and radioactivity was determined in plasma, liver, and feces. T0901317-treated mice presented increased [³H]cholesterol in plasma and HDL 48 h after the label injection. Treatment with T0901317 also increased liver ABCA1, G1, and G5 gene expression and reduced intestinal cholesterol absorption which were changes that were associated with a 2.8-fold increase in macrophage-derived [³H]cholesterol in feces. In contrast, resveratrol treatment had no effect on liver LXR signaling or fecal [³H]cholesterol excretion. A separate experiment was conducted in SIRT1 transgenic mice. Liver LXR-target gene expression and magnitude of macrophage-derived [³H]cholesterol in plasma, liver, and feces of SIRT1 transgenic mice did not differ from those of wild-type mice. We conclude that neither resveratrol administration nor SIRT1 overexpression upregulate liver LXR-target genes and macrophage-to-feces RCT in vivo.
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Affiliation(s)
- Joan Carles Escolà-Gil
- IIB Sant Pau, Barcelona, Spain; CIBER de Diabetes y Enfermedades Metabólicas Asociadas, CIBERDEM, Barcelona, Spain.
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Modulation of lipoprotein metabolism by antisense technology: preclinical drug discovery methodology. Methods Mol Biol 2013; 1027:309-24. [PMID: 23912993 DOI: 10.1007/978-1-60327-369-5_14] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
Antisense oligonucleotides (ASOs) are a new class of specific therapeutic agents that alter the intermediary metabolism of mRNA, resulting in the suppression of disease-associated gene products. ASOs exert their pharmacological effects after hybridizing, via Watson-Crick base pairing, to a specific target RNA. If appropriately designed, this event results in the recruitment of RNase H, the degradation of targeted mRNA or pre-mRNA, and subsequent inhibition of the synthesis of a specific protein. A key advantage of the technology is the ability to selectively inhibit targets that cannot be modulated by traditional therapeutics such as structural proteins, transcription factors, and, of topical interest, lipoproteins. In this chapter, we will first provide an overview of antisense technology, then more specifically describe the status of lipoprotein-related genes that have been studied using the antisense platform, and finally, outline the general methodology required to design and evaluate the in vitro and in vivo efficacy of those drugs.
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