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Rahunen R, Tulppo M, Rinne V, Lepojärvi S, Perkiömäki JS, Huikuri HV, Ukkola O, Junttila J, Hukkanen J. Liver X Receptor Agonist 4β-Hydroxycholesterol as a Prognostic Factor in Coronary Artery Disease. J Am Heart Assoc 2024; 13:e031824. [PMID: 38390795 PMCID: PMC10944077 DOI: 10.1161/jaha.123.031824] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/15/2023] [Accepted: 01/05/2024] [Indexed: 02/24/2024]
Abstract
BACKGROUND Regardless of progress in treatment of coronary artery disease (CAD), there is still a significant residual risk of death in patients with CAD, highlighting the need for additional risk stratification markers. Our previous study provided evidence for a novel blood pressure-regulating mechanism involving 4β-hydroxycholesterol (4βHC), an agonist for liver X receptors, as a hypotensive factor. The aim was to determine the role of 4βHC as a prognostic factor in CAD. METHODS AND RESULTS The ARTEMIS (Innovation to Reduce Cardiovascular Complications of Diabetes at the Intersection) cohort consists of 1946 patients with CAD. Men and women were analyzed separately in quartiles according to plasma 4βHC. Basic characteristics, medications, ECG, and echocardiography parameters as well as mortality rate were analyzed. At baseline, subjects with a beneficial cardiovascular profile, as assessed with traditional markers such as body mass index, exercise capacity, prevalence of diabetes, and use of antihypertensives, had the highest plasma 4βHC concentrations. However, in men, high plasma 4βHC was associated with all-cause death, cardiac death, and especially sudden cardiac death (SCD) in a median follow-up of 8.8 years. Univariate and comprehensively adjusted hazard ratios for SCD in the highest quartile were 3.76 (95% CI, 1.6-8.7; P=0.002) and 4.18 (95% CI, 1.5-11.4; P=0.005), respectively. In contrast, the association of cardiac death and SCD in women showed the lowest risk in the highest 4βHC quartile. CONCLUSIONS High plasma 4βHC concentration was associated with death and especially SCD in men, while an inverse association was detected in women. Our results suggest 4βHC as a novel sex-specific risk marker of cardiac death and especially SCD in chronic CAD. REGISTRATION INFORMATION clinicaltrials.gov. Identifier NCT01426685.
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Affiliation(s)
- Roosa Rahunen
- Research Unit of Biomedicine and Internal MedicineUniversity of OuluOuluFinland
- Biocenter OuluUniversity of OuluOuluFinland
- Medical Research Center OuluOulu University Hospital and University of OuluOuluFinland
| | - Mikko Tulppo
- Research Unit of Biomedicine and Internal MedicineUniversity of OuluOuluFinland
- Medical Research Center OuluOulu University Hospital and University of OuluOuluFinland
| | | | - Samuli Lepojärvi
- Research Unit of Biomedicine and Internal MedicineUniversity of OuluOuluFinland
- Medical Research Center OuluOulu University Hospital and University of OuluOuluFinland
| | - Juha S. Perkiömäki
- Research Unit of Biomedicine and Internal MedicineUniversity of OuluOuluFinland
- Medical Research Center OuluOulu University Hospital and University of OuluOuluFinland
| | - Heikki V. Huikuri
- Research Unit of Biomedicine and Internal MedicineUniversity of OuluOuluFinland
- Medical Research Center OuluOulu University Hospital and University of OuluOuluFinland
| | - Olavi Ukkola
- Research Unit of Biomedicine and Internal MedicineUniversity of OuluOuluFinland
- Medical Research Center OuluOulu University Hospital and University of OuluOuluFinland
| | - Juhani Junttila
- Research Unit of Biomedicine and Internal MedicineUniversity of OuluOuluFinland
- Biocenter OuluUniversity of OuluOuluFinland
- Medical Research Center OuluOulu University Hospital and University of OuluOuluFinland
| | - Janne Hukkanen
- Research Unit of Biomedicine and Internal MedicineUniversity of OuluOuluFinland
- Biocenter OuluUniversity of OuluOuluFinland
- Medical Research Center OuluOulu University Hospital and University of OuluOuluFinland
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2
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Che X, Xiao Q, Song W, Zhang H, Sun B, Geng N, Tao Z, Shao Q, Pu J. Protective Functions of Liver X Receptor α in Established Vulnerable Plaques: Involvement of Regulating Endoplasmic Reticulum-Mediated Macrophage Apoptosis and Efferocytosis. J Am Heart Assoc 2021; 10:e018455. [PMID: 33969692 PMCID: PMC8200716 DOI: 10.1161/jaha.120.018455] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
Background Liver X receptor (LXR) belongs to the metabolic nuclear receptor superfamily, which plays a critical regulatory role in vascular physiology/pathology. However, effects of systemic LXR activation on established vulnerable plaques and the potential isotype‐specific role involved remain unclear. Methods and Results The 8‐week‐old male apolipoprotein E−/− mice went through carotid branch ligation and renal artery constriction, combined with a high‐fat diet. Plaques in the left carotid artery acquired vulnerable features 4 weeks later, confirmed by magnetic resonance imaging scans and histological analysis. From that time on, mice were injected intraperitoneally daily with PBS or GW3965 (10 mg/kg per day) for an additional 4 weeks. Treatment with LXR agonists reduced the lesion volume by 52.61%, compared with the vehicle group. More important, a profile of less intraplaque hemorrhage detection and necrotic core formation was found. These actions collectively attenuated the incidence of plaque rupture. Mechanistically, reduced lesional apoptosis, enhanced efferocytosis, and alleviated endoplasmic reticulum stress are involved in the process. Furthermore, genetic ablation of LXRα, but not LXRβ, blunted the protective effects of LXR on the endoplasmic reticulum stress–elicited C/EBP‐homologous protein pathway in peritoneal macrophages. In concert with the LXRα‐predominant role in vitro, activated LXR failed to stabilize vulnerable plaques and correct the acquired cellular anomalies in LXRα−/− apolipoprotein E−/− mice. Conclusions Our results revealed that LXRα mediates the capacity of LXR activation to stabilize vulnerable plaques and prevent plaque rupture via amelioration of macrophage endoplasmic reticulum stress, lesional apoptosis, and defective efferocytosis. These findings might expand the application scenarios of LXR therapeutics for atherosclerosis.
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Affiliation(s)
- Xinyu Che
- Department of Cardiology Renji Hospital School of Medicine Shanghai Jiao Tong University Shanghai China
| | - Qingqing Xiao
- Department of Cardiology Renji Hospital School of Medicine Shanghai Jiao Tong University Shanghai China
| | - Wei Song
- Cardiovascular Department of Shuguang Hospital Affiliated to Shanghai University of Traditional Chinese Medicine Shanghai China
| | - Hengyuan Zhang
- Department of Cardiology Renji Hospital School of Medicine Shanghai Jiao Tong University Shanghai China
| | - Beibei Sun
- Department of Radiology Renji Hospital School of Medicine Shanghai Jiao Tong University Shanghai China
| | - Na Geng
- Department of Cardiology Renji Hospital School of Medicine Shanghai Jiao Tong University Shanghai China
| | - Zhenyu Tao
- Department of Cardiology Renji Hospital School of Medicine Shanghai Jiao Tong University Shanghai China
| | - Qin Shao
- Department of Cardiology Renji Hospital School of Medicine Shanghai Jiao Tong University Shanghai China
| | - Jun Pu
- Department of Cardiology Renji Hospital School of Medicine Shanghai Jiao Tong University Shanghai China
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A-Gonzalez N, Guillen JA, Gallardo G, Diaz M, de la Rosa JV, Hernandez IH, Casanova-Acebes M, Lopez F, Tabraue C, Beceiro S, Hong C, Lara PC, Andujar M, Arai S, Miyazaki T, Li S, Corbi AL, Tontonoz P, Hidalgo A, Castrillo A. The nuclear receptor LXRα controls the functional specialization of splenic macrophages. Nat Immunol 2013; 14:831-9. [PMID: 23770640 PMCID: PMC3720686 DOI: 10.1038/ni.2622] [Citation(s) in RCA: 123] [Impact Index Per Article: 11.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2013] [Accepted: 04/24/2013] [Indexed: 12/12/2022]
Abstract
Macrophages are professional phagocytic cells that orchestrate innate immune responses and display remarkable phenotypic diversity at different anatomical locations. However, the mechanisms that control the heterogeneity of tissue macrophages are not well characterized. Here, we report that the nuclear receptor LXRα is essential for the differentiation of macrophages in the marginal zone (MZ) of the spleen. LXR deficient mice are defective in the generation of MZ and metallophilic macrophages, resulting in abnormal responses to blood-borne antigens. Myeloid specific expression of LXRα or adoptive transfer of wild-type monocytes rescues the MZ microenvironment in LXRα deficient mice. These results demonstrate that LXRα signaling in myeloid cells is crucial for the generation of splenic MZ macrophages and reveal an unprecedented role for a nuclear receptor in the generation of specialized macrophage subsets.
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Affiliation(s)
- Noelia A-Gonzalez
- Instituto de Investigaciones Biomédicas Alberto Sols de Madrid, Consejo Superior de Investigaciones Cientificas-Universidad Autonóma de Madrid, Madrid, Spain
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4
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Feldmann R, Fischer C, Kodelja V, Behrens S, Haas S, Vingron M, Timmermann B, Geikowski A, Sauer S. Genome-wide analysis of LXRα activation reveals new transcriptional networks in human atherosclerotic foam cells. Nucleic Acids Res 2013; 41:3518-31. [PMID: 23393188 PMCID: PMC3616743 DOI: 10.1093/nar/gkt034] [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] [Indexed: 01/10/2023] Open
Abstract
Increased physiological levels of oxysterols are major risk factors for developing atherosclerosis and cardiovascular disease. Lipid-loaded macrophages, termed foam cells, are important during the early development of atherosclerotic plaques. To pursue the hypothesis that ligand-based modulation of the nuclear receptor LXRα is crucial for cell homeostasis during atherosclerotic processes, we analysed genome-wide the action of LXRα in foam cells and macrophages. By integrating chromatin immunoprecipitation-sequencing (ChIP-seq) and gene expression profile analyses, we generated a highly stringent set of 186 LXRα target genes. Treatment with the nanomolar-binding ligand T0901317 and subsequent auto-regulatory LXRα activation resulted in sequence-dependent sharpening of the genome-binding patterns of LXRα. LXRα-binding loci that correlated with differential gene expression revealed 32 novel target genes with potential beneficial effects, which in part explained the implications of disease-associated genetic variation data. These observations identified highly integrated LXRα ligand-dependent transcriptional networks, including the APOE/C1/C4/C2-gene cluster, which contribute to the reversal of cholesterol efflux and the dampening of inflammation processes in foam cells to prevent atherogenesis.
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Affiliation(s)
- Radmila Feldmann
- Max Planck Institute for Molecular Genetics, Ihnestraße 63-73, 14195 Berlin, Germany
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5
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Bentinger M, Tekle M, Dallner G, Brismar K, Gustafsson JÅ, Steffensen KR, Catrina SB. Influence of liver-X-receptor on tissue cholesterol, coenzyme Q and dolichol content. Mol Membr Biol 2012; 29:299-308. [PMID: 22694168 DOI: 10.3109/09687688.2012.694484] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
The organ content of the mevalonate pathway lipids was investigated in liver-X-receptor (LXR) α, β and double knock-out mice. An extensive or moderate increase of total cholesterol in the double KO mice was found in all organs elicited by the increase of the esterified form. In LXRα and double KO mice, coenzyme Q (CoQ) was decreased in liver and increased in spleen, thymus and lung, while dolichol was increased in all organs investigated. This effect was confirmed using LXR- agonist GW 3965. Analysis of CoQ distribution in organelles showed that the modifications are present in all cellular compartments and that the increase of the lipid in mitochondria was the result of a net increase of CoQ without changing the number of mitochondria. It appears that LXR influences not only cellular cholesterol homeostasis but also the metabolism of CoQ and dolichol, in an indirect manner.
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Affiliation(s)
- Magnus Bentinger
- Rolf Luft Research Center for Diabetes and Endocrinology, Karolinska Institutet, Stockholm, Sweden
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6
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Na TY, Lee HJ, Oh HJ, Huh S, Lee IK, Lee MO. Positive Cross-Talk Between Hypoxia Inducible Factor-1α and Liver X Receptor α Induces Formation of Triglyceride-Loaded Foam Cells. Arterioscler Thromb Vasc Biol 2011; 31:2949-56. [DOI: 10.1161/atvbaha.111.235788] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Objective—
Atherosclerosis is a chronic and progressive inflammatory disease of the arteries that is characterized by subendothelial accumulation of lipid-rich macrophages, called foam cells. We sought to identify the molecular details of cross-talk between liver X receptor α (LXRα) and hypoxia-inducible factor 1α (HIF-1α) for the formation of triglyceride-rich foam cells under hypoxic conditions.
Methods and Results—
We first observed that expression of LXRα and its target lipogenic genes was time-dependently induced in human primary macrophages and RAW 264.7 cells under hypoxia. Similarly, TO901317, an activator of LXRα, enhanced the expression level and the transcriptional activity of HIF-1α. Second, we demonstrated that LXRα increased HIF-1α protein stability through a physical interaction between the ligand binding domain of LXRα and the oxygen-dependent degradation domain of HIF-1α. Third, we found that the activation of HIF-1α or LXRα synergistically induced triglyceride accumulation in macrophages. Finally, we showed that LXRα and HIF-1α were codistributed in the macrophages of atherosclerotic lesions of patients.
Conclusion—
These results suggest that the positive feed-forward regulation of transcriptional activity and protein stability of LXRα and HIF-1α has an important impact in foam cell formation.
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Affiliation(s)
- Tae-Young Na
- From the College of Pharmacy and Bio-MAX Institute, Seoul National University, Seoul (T.Y.N., H.J.O., M.O.L.); and Department of Internal Medicine and WCU program (H.J.L., I.K.L.), Department of Surgery (S.H.), Kyungpook National University School of Medicine, Daegu, Korea
| | - Hyo-Jeong Lee
- From the College of Pharmacy and Bio-MAX Institute, Seoul National University, Seoul (T.Y.N., H.J.O., M.O.L.); and Department of Internal Medicine and WCU program (H.J.L., I.K.L.), Department of Surgery (S.H.), Kyungpook National University School of Medicine, Daegu, Korea
| | - Hyeon-Jeong Oh
- From the College of Pharmacy and Bio-MAX Institute, Seoul National University, Seoul (T.Y.N., H.J.O., M.O.L.); and Department of Internal Medicine and WCU program (H.J.L., I.K.L.), Department of Surgery (S.H.), Kyungpook National University School of Medicine, Daegu, Korea
| | - Seung Huh
- From the College of Pharmacy and Bio-MAX Institute, Seoul National University, Seoul (T.Y.N., H.J.O., M.O.L.); and Department of Internal Medicine and WCU program (H.J.L., I.K.L.), Department of Surgery (S.H.), Kyungpook National University School of Medicine, Daegu, Korea
| | - In-Kyu Lee
- From the College of Pharmacy and Bio-MAX Institute, Seoul National University, Seoul (T.Y.N., H.J.O., M.O.L.); and Department of Internal Medicine and WCU program (H.J.L., I.K.L.), Department of Surgery (S.H.), Kyungpook National University School of Medicine, Daegu, Korea
| | - Mi-Ock Lee
- From the College of Pharmacy and Bio-MAX Institute, Seoul National University, Seoul (T.Y.N., H.J.O., M.O.L.); and Department of Internal Medicine and WCU program (H.J.L., I.K.L.), Department of Surgery (S.H.), Kyungpook National University School of Medicine, Daegu, Korea
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Abstract
Atherosclerosis is a chronic immunoinflammatory disease involving medium and large arteries, resulting from a complex interaction between genetic and environmental risk factors. Acute atherosclerotic vascular disease largely results from thrombosis that supervenes on a disrupted atherosclerotic plaque. A healthy lifestyle coupled with management of modifiable risk factors reduces the adverse clinical consequences of atherothrombosis. Reducing low-density lipoprotein cholesterol levels using statins and other agents is the primary pharmacologic approach to stabilize atherosclerosis, but a large residual risk burden remains, stimulating the search for additional therapies for atherosclerosis management. This review focuses on new and emerging therapeutic strategies targeting atherosclerosis.
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Sato K, Kamada T. Regulation of bile acid, cholesterol, and fatty acid synthesis in chicken primary hepatocytes by different concentrations of T0901317, an agonist of liver X receptors. Comp Biochem Physiol A Mol Integr Physiol 2010; 158:201-6. [PMID: 21056113 DOI: 10.1016/j.cbpa.2010.10.028] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2010] [Revised: 10/26/2010] [Accepted: 10/26/2010] [Indexed: 11/24/2022]
Abstract
Liver X receptors (LXRs) are members of the nuclear receptor family of transcription factors. They play a crucial role in lipid metabolism processes such as bile acid and fatty acid synthesis, as well as minor or limited roles in the regulation of cholesterol synthesis and uptake in mammals. In avian species, however, little is known about the role of LXRs except for the fact that they are involved in the stimulation of fatty acid synthesis. In this study, we characterize the expression profile of genes related to bile acid, cholesterol, and fatty acid synthesis and VLDL secretion in chicken primary hepatocytes treated with T0901317, a synthetic agonist of LXR. The activity of chicken cholesterol 7α hydroxylase (CYP7A1), a key enzyme in bile acid synthesis, mRNA expression, and bile acid excretion, was stimulated by supplementation of the culture medium with a low concentration (0.01 μM) of T0901317. In contrast, the levels of sterol regulatory element binding protein (SREBP)-1, fatty acid synthase mRNA, and VLDL-triacylglycerol in cells cultured in the presence of a high concentration (10 μM) of T0901317 were higher than those cultured in zero or low concentrations of T0901317. These results suggest that cellular responses to this LXR agonist were similar to those present in mammals. A novel finding of this study concerned changes to the regulation of cholesterol synthesis and uptake in chicken hepatocytes treated with T0901317. Levels of SREBP-2,3-hydroxy-3-methylglutaryl coenzyme A reductase (HMGR) and low-density lipoprotein receptor (LDLr) mRNA expression increased as a function of increasing T0901317 (up to 1.0 μM), but remained similar to those in cells cultured under control conditions when the concentration of T0901317 was increased to 10 μM. These results suggest that LXRs play an important role in cholesterol synthesis and uptake in chicken hepatocytes and, as such, differ to findings in mammals where the effect of LXR agonists on cholesterol synthesis plays only a minor role in the regulation of cellular sterol homeostasis.
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Affiliation(s)
- Kan Sato
- Animal Science, Department of Biological Production, Tokyo University of Agriculture and Technology, 3-5-8, Saiwai-cho, Fuchu-shi, Tokyo, 183-8509, Japan.
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9
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Weedon-Fekjær M, Johnsen G, Anthonisen E, Sugulle M, Nebb H, Duttaroy A, Staff A. Expression of Liver X Receptors in Pregnancies Complicated by Preeclampsia. Placenta 2010; 31:818-24. [DOI: 10.1016/j.placenta.2010.06.015] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/16/2009] [Revised: 05/27/2010] [Accepted: 06/24/2010] [Indexed: 10/19/2022]
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10
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Abstract
The steroidal receptors play a key role in protein synthesis and maintain the homeostasis in normal and diseased state, including tumorigenesis at the target tissues when overactivated. Thus steroidal receptors may act as potential targets for selective delivery of different therapeutic agents as they are overexpressed by a number of endocrinal tumors. The selective delivery of these agents may be a better treatment strategy for endocrinal cancer as it may also result in cytosolic and nuclear delivery of cytotoxic agents. In this review, the targeting potential of steroidal receptors for the drug or bioactive(s) delivery is discussed. The ligands that have been proven to be effective for specific steroidal receptors can be used as vectors for carrying the drug or drug-delivery system to the desired site of drug action in an optimum concentration. This strategy will not only minimize the undesired side effects associated with nonspecific delivery of drug, but will also maximize the drug utilization. Ligand-conjugated liposomes as a carrier of bioactives prevent passive diffusion of the encapsulated drug to normal cells, increase the time of circulation and reduce the undesirable side effects of a drug.
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11
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Dave VP, Kaul D. Coronary heart disease: Significance of liver X receptor α genomics. World J Cardiol 2010; 2:140-9. [PMID: 21160732 PMCID: PMC2999051 DOI: 10.4330/wjc.v2.i6.140] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/18/2010] [Revised: 06/11/2010] [Accepted: 06/18/2010] [Indexed: 02/06/2023] Open
Abstract
Crosstalk between lipid peroxidation and inflammation is known to be a pathognomonic feature for the development of coronary heart disease (CHD). In this regard ligand activated liver X receptor (LXR)-α has emerged as a key molecular switch by its inherent ability to modulate an array of genes involved in these two fundamental cellular processes. In addition, LXR-α has also been found to play a role in hepatic lipogenesis and innate immunity. Although several lines of evidence in experimental model systems have established the atheroprotective nature of LXR-α, human subjects have been reported to possess a paradoxical situation in which increased blood cellular LXR-α gene expression is always accompanied by increased coronary occlusion. This apparent paradox was resolved recently by the finding that CHD patients possess a deregulated LXR-α transcriptome due to impaired ligand-receptor interaction. This blood cellular mutated LXR-α gene expression correlated specifically with the extent of coronary occlusion and hence need is felt to devise new synthetic ligands that could restore the function of this mutated LXR-α protein in order to modulate genes involved in reverse cholesterol transport and suppression of the inflammatory response leading to the effective treatment of CHD.
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Affiliation(s)
- Vivek Priy Dave
- Vivek Priy Dave, Deepak Kaul, Department of Experimental Medicine and Biotechnology, Post Graduate Institute of Medical Education and Research, Chandigarh 160012, India
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12
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Kazawa T, Kawasaki T, Sakamoto A, Imamura M, Ohashi R, Jiang S, Tanaka T, Iwanari H, Hamakubo T, Sakai J, Kodama T, Naito M. Expression of liver X receptor α and lipid metabolism in granulocyte-macrophage colony-stimulating factor-induced human monocyte-derived macrophage. Pathol Int 2009; 59:152-60. [DOI: 10.1111/j.1440-1827.2009.02343.x] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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13
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Takegoshi S, Jiang S, Ohashi R, Savchenko AS, Iwanari H, Tanaka T, Hasegawa G, Hamakubo T, Kodama T, Naito M. Protein expression of nuclear receptors in human and murine tissues. Pathol Int 2009; 59:61-72. [DOI: 10.1111/j.1440-1827.2008.02330.x] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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Russell LE, Harrison WJ, Bahta AW, Zouboulis CC, Burrin JM, Philpott MP. Characterization of liver X receptor expression and function in human skin and the pilosebaceous unit. Exp Dermatol 2007; 16:844-52. [PMID: 17845217 DOI: 10.1111/j.1600-0625.2007.00612.x] [Citation(s) in RCA: 54] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
The nuclear receptors liver X receptor alpha (LXRalpha) and liver X-receptor beta (LXRbeta) have a well documented role in cholesterol homeostasis and lipid metabolism within tissues and cells including the liver, small intestine and macrophages. In keratinocytes, LXRs have been shown to up-regulate differentiation in vitro via increased transcription of proteins of the AP1 complex and to down-regulate proliferation in vivo. In this study, we provide a detailed description of the location and possible role of LXRs within human skin and its associated glands and appendages. Using RT-PCR, Western blotting and immunohistochemistry, we have demonstrated expression of LXRalpha and LXRbeta mRNA and proteins in whole human skin as well as within a range of primary and immortalized human cell lines derived from human skin, hair follicle and sebaceous glands. Furthermore, we have shown that synthetic LXR specific agonists GW683965 and TO901317 significantly inhibit cell proliferation in primary epidermal keratinocytes, immortalized N/TERT keratinocytes and the immortalized SZ95 sebocyte line, and significantly increase lipogenesis in SZ95 sebocytes. In addition, we showed that the synthetic agonist TO901317 significantly reduced hair growth, in vitro.
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Affiliation(s)
- Louise E Russell
- Centre for Cutaneous Research and Centre for Endocrinology, Bart's and The London Queen Mary's School of Medicine and Dentistry, Queen Mary College, University of London, London, UK
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Sakamoto A, Kawasaki T, Kazawa T, Ohashi R, Jiang S, Maejima T, Tanaka T, Iwanari H, Hamakubo T, Sakai J, Kodama T, Naito M. Expression of Liver X Receptor α in Rat Fetal Tissues at Different Developmental Stages. J Histochem Cytochem 2007; 55:641-9. [PMID: 17341476 DOI: 10.1369/jhc.6a7120.2007] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
The liver X receptor (LXR) is a nuclear receptor that acts as a sterol sensor and metabolic regulator of cholesterol and lipid homeostasis. Using a novel LXRα-specific antibody for immunohistochemistry, we evaluated cellular expression of LXRα in fetal rat tissues. In the fetal liver, LXRα-positive macrophages appeared at 12 days and their number peaked at 18 days of gestation. In contrast, hepatocytes expressed LXRα during the later stage of gestation, suggesting the functional development of the liver during ontogeny. Later, macrophages in spleen and thymus expressed LXRα, and some mononuclear cells in the vascular lumen compatible to primitive/fetal macrophages in the fetal circulation were found to express LXRα. In vitro, rat monocytes did not express LXRα, but monocyte-derived macrophages cultured in the presence of macrophage-colony stimulating factor revealed the distinct expression of LXRα in nucleoli. These findings suggest that LXRα plays a role in the differentiation of fetal macrophages, particularly hepatic macrophages, in rat development.
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Affiliation(s)
- Azusa Sakamoto
- Division of Cellular and Molecular Pathology, Department of Cellular Function, Niigata University Graduate School of Medical and Dental Sciences, Asahimachi-dori 1-757, 951-8510, Niigata, Japan
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Bennett DJ, Brown LD, Cooke AJ, Edwards AS. An update on non-steroidal liver X receptor agonists and their potential use in the treatment of atherosclerosis. Expert Opin Ther Pat 2006. [DOI: 10.1517/13543776.16.12.1673] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
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18
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Ito H, Funahashi SI, Yamauchi N, Shibahara J, Midorikawa Y, Kawai S, Kinoshita Y, Watanabe A, Hippo Y, Ohtomo T, Iwanari H, Nakajima A, Makuuchi M, Fukayama M, Hirata Y, Hamakubo T, Kodama T, Tsuchiya M, Aburatani H. Identification of ROBO1 as a novel hepatocellular carcinoma antigen and a potential therapeutic and diagnostic target. Clin Cancer Res 2006; 12:3257-64. [PMID: 16740745 DOI: 10.1158/1078-0432.ccr-05-2787] [Citation(s) in RCA: 75] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
PURPOSE Hepatocellular carcinoma is the most common primary malignancy of the liver and accounts for as many as one million deaths annually worldwide. The present study was done to identify new transmembrane molecules for antibody therapy in hepatocellular carcinoma. EXPERIMENTAL DESIGN Gene expression profiles of pooled total RNA from three tissues each of moderately differentiated and poorly differentiated hepatocellular carcinoma were compared with those of normal liver, noncancerous liver tissue in hepatocellular carcinoma patients, 30 normal tissue samples, and five fetal tissue samples. Target genes up-regulated specifically in hepatocellular carcinoma were validated by immunohistochemical analysis and complement-dependent cytotoxicity assay using monoclonal antibodies generated against target molecules. RESULTS The human homologue of the Drosophila Roundabout gene, axon guidance receptor homologue 1, ROBO1/DUTT1, a member of the immunoglobulin superfamily, was highly expressed in hepatocellular carcinoma, whereas it showed only a limited distribution in normal tissues. On immunohistochemical analysis using a newly generated anti-ROBO1 monoclonal antibody, positive signals were observed in 83 of 98 cases of hepatocellular carcinoma (84.7%). The mAb B2318C induced complement-dependent cytotoxicity in ROBO1-expressing cell lines and in the liver cancer cell line PLC/PRF/5. Strikingly, the ectodomain of ROBO1 was detected not only in the culture medium of liver cancer cell lines (PLC/PRF/5, HepG2, etc.) but also in sera from hepatocellular carcinoma patients (6 of 11). CONCLUSIONS This is the first report that ROBO1 is overexpressed in hepatocellular carcinoma and shed into serum in humans. These observations suggest that ROBO1 is a potential new serologic marker for hepatocellular carcinoma and may represent a new therapeutic target.
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MESH Headings
- Animals
- Antibodies, Monoclonal/pharmacology
- Biomarkers, Tumor/biosynthesis
- Biomarkers, Tumor/blood
- Biomarkers, Tumor/genetics
- COS Cells
- Carcinoma, Hepatocellular/blood
- Carcinoma, Hepatocellular/diagnosis
- Carcinoma, Hepatocellular/genetics
- Cell Line, Tumor
- Cell Proliferation/drug effects
- Chlorocebus aethiops
- Cytotoxicity Tests, Immunologic
- Gene Expression Profiling
- Gene Expression Regulation, Neoplastic
- Humans
- Immunohistochemistry
- Liver Neoplasms/blood
- Liver Neoplasms/diagnosis
- Liver Neoplasms/genetics
- Nerve Tissue Proteins/biosynthesis
- Nerve Tissue Proteins/blood
- Nerve Tissue Proteins/genetics
- Protein Structure, Tertiary
- RNA, Messenger/biosynthesis
- Receptors, Immunologic/biosynthesis
- Receptors, Immunologic/blood
- Receptors, Immunologic/genetics
- Reverse Transcriptase Polymerase Chain Reaction/methods
- Up-Regulation/genetics
- Roundabout Proteins
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Affiliation(s)
- Hirotaka Ito
- Genome Science Division, Research Center for Advanced Science and Technology, the University of Tokyo, Japan
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Morello F, de Boer RA, Steffensen KR, Gnecchi M, Chisholm JW, Boomsma F, Anderson LM, Lawn RM, Gustafsson JA, Lopez-Ilasaca M, Pratt RE, Dzau VJ. Liver X receptors alpha and beta regulate renin expression in vivo. J Clin Invest 2005; 115:1913-22. [PMID: 16007255 PMCID: PMC1159146 DOI: 10.1172/jci24594] [Citation(s) in RCA: 78] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2005] [Accepted: 05/10/2005] [Indexed: 12/21/2022] Open
Abstract
The renin-angiotensin-aldosterone system controls blood pressure and salt-volume homeostasis. Renin, which is the first enzymatic step of the cascade, is critically regulated at the transcriptional level. In the present study, we investigated the role of liver X receptor alpha (LXR(alpha)) and LXR(beta) in the regulation of renin. In vitro, both LXRs could bind to a noncanonical responsive element in the renin promoter and regulated renin transcription. While LXR(alpha) functioned as a cAMP-activated factor, LXR(beta) was inversely affected by cAMP. In vivo, LXRs colocalized in juxtaglomerular cells, in which LXR(alpha) was specifically enriched, and interacted with the renin promoter. In mouse models, renin-angiotensin activation was associated with increased binding of LXR(alpha) to the responsive element. Moreover, acute administration of LXR agonists was followed by upregulation of renin transcription. In LXR(alpha) mice, the elevation of renin triggered by adrenergic stimulation was abolished. Untreated LXR(beta) mice exhibited reduced kidney renin mRNA levels compared with controls. LXR(alpha)LXR(beta) mice showed a combined phenotype of lower basal renin and blunted adrenergic response. In conclusion, we show herein that LXR(alpha) and LXR(beta) regulate renin expression in vivo by directly interacting with the renin promoter and that the cAMP/LXR(alpha) signaling pathway is required for the adrenergic control of the renin-angiotensin system.
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