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Chen L, Ma J, Xu W, Shen F, Yang Z, Sonne C, Dietz R, Li L, Jie X, Li L, Yan G, Zhang X. Comparative transcriptome and methylome of polar bears, giant and red pandas reveal diet-driven adaptive evolution. Evol Appl 2024; 17:e13731. [PMID: 38894980 PMCID: PMC11183199 DOI: 10.1111/eva.13731] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2023] [Revised: 05/18/2024] [Accepted: 05/27/2024] [Indexed: 06/21/2024] Open
Abstract
Epigenetic regulation plays an important role in the evolution of species adaptations, yet little information is available on the epigenetic mechanisms underlying the adaptive evolution of bamboo-eating in both giant pandas (Ailuropoda melanoleuca) and red pandas (Ailurus fulgens). To investigate the potential contribution of epigenetic to the adaptive evolution of bamboo-eating in giant and red pandas, we performed hepatic comparative transcriptome and methylome analyses between bamboo-eating pandas and carnivorous polar bears (Ursus maritimus). We found that genes involved in carbohydrate, lipid, amino acid, and protein metabolism showed significant differences in methylation and expression levels between the two panda species and polar bears. Clustering analysis of gene expression revealed that giant pandas did not form a sister group with the more closely related polar bears, suggesting that the expression pattern of genes in livers of giant pandas and red pandas have evolved convergently driven by their similar diets. Compared to polar bears, some key genes involved in carbohydrate metabolism and biological oxidation and cholesterol synthesis showed hypomethylation and higher expression in giant and red pandas, while genes involved in fat digestion and absorption, fatty acid metabolism, lysine degradation, resistance to lipid peroxidation and detoxification showed hypermethylation and low expression. Our study elucidates the special nutrient utilization mechanism of giant pandas and red pandas and provides some insights into the molecular mechanism of their adaptive evolution of bamboo feeding. This has important implications for the breeding and conservation of giant pandas and red pandas.
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Affiliation(s)
- Lei Chen
- Key Laboratory of bio‐Resources and eco‐Environment, Ministry of Education, College of Life ScienceSichuan UniversityChengduChina
| | - Jinnan Ma
- Key Laboratory of bio‐Resources and eco‐Environment, Ministry of Education, College of Life ScienceSichuan UniversityChengduChina
- College of Continuing EducationYunnan Normal UniversityKunmingChina
| | - Wencai Xu
- Key Laboratory of bio‐Resources and eco‐Environment, Ministry of Education, College of Life ScienceSichuan UniversityChengduChina
| | - Fujun Shen
- Sichuan Key Laboratory for Conservation Biology of Endangered WildlifeChengdu Research Base of Giant Panda BreedingChengduChina
| | | | - Christian Sonne
- Arctic Research Centre, Faculty of Science and Technology, Department of EcoscienceAarhus UniversityRoskildeDenmark
| | - Rune Dietz
- Arctic Research Centre, Faculty of Science and Technology, Department of EcoscienceAarhus UniversityRoskildeDenmark
| | - Linzhu Li
- Key Laboratory of bio‐Resources and eco‐Environment, Ministry of Education, College of Life ScienceSichuan UniversityChengduChina
| | - Xiaodie Jie
- Key Laboratory of bio‐Resources and eco‐Environment, Ministry of Education, College of Life ScienceSichuan UniversityChengduChina
| | - Lu Li
- Key Laboratory of bio‐Resources and eco‐Environment, Ministry of Education, College of Life ScienceSichuan UniversityChengduChina
| | - Guoqiang Yan
- Key Laboratory of bio‐Resources and eco‐Environment, Ministry of Education, College of Life ScienceSichuan UniversityChengduChina
| | - Xiuyue Zhang
- Key Laboratory of bio‐Resources and eco‐Environment, Ministry of Education, College of Life ScienceSichuan UniversityChengduChina
- Sichuan Key Laboratory of Conservation Biology on Endangered Wildlife, College of Life SciencesSichuan UniversityChengduChina
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2
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Petrenko V, Sinturel F, Riezman H, Dibner C. Lipid metabolism around the body clocks. Prog Lipid Res 2023; 91:101235. [PMID: 37187314 DOI: 10.1016/j.plipres.2023.101235] [Citation(s) in RCA: 15] [Impact Index Per Article: 15.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2023] [Revised: 04/06/2023] [Accepted: 05/12/2023] [Indexed: 05/17/2023]
Abstract
Lipids play important roles in energy metabolism along with diverse aspects of biological membrane structure, signaling and other functions. Perturbations of lipid metabolism are responsible for the development of various pathologies comprising metabolic syndrome, obesity, and type 2 diabetes. Accumulating evidence suggests that circadian oscillators, operative in most cells of our body, coordinate temporal aspects of lipid homeostasis. In this review we summarize current knowledge on the circadian regulation of lipid digestion, absorption, transportation, biosynthesis, catabolism, and storage. Specifically, we focus on the molecular interactions between functional clockwork and biosynthetic pathways of major lipid classes comprising cholesterol, fatty acids, triacylglycerols, glycerophospholipids, glycosphingolipids, and sphingomyelins. A growing body of epidemiological studies associate a socially imposed circadian misalignment common in modern society with growing incidence of metabolic disorders, however the disruption of lipid metabolism rhythms in this connection has only been recently revealed. Here, we highlight recent studies that unravel the mechanistic link between intracellular molecular clocks, lipid homeostasis and development of metabolic diseases based on animal models of clock disruption and on innovative translational studies in humans. We also discuss the perspectives of manipulating circadian oscillators as a potentially powerful approach for preventing and managing metabolic disorders in human patients.
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Affiliation(s)
- Volodymyr Petrenko
- Thoracic and Endocrine Surgery Division, Department of Surgery, University Hospital of Geneva, Geneva 1211, Switzerland; Department of Cell Physiology and Metabolism, Faculty of Medicine, University of Geneva, Geneva 1211, Switzerland; Diabetes Center, Faculty of Medicine, University of Geneva, Geneva 1211, Switzerland; Institute of Genetics and Genomics in Geneva (iGE3), Geneva 1211, Switzerland
| | - Flore Sinturel
- Thoracic and Endocrine Surgery Division, Department of Surgery, University Hospital of Geneva, Geneva 1211, Switzerland; Department of Cell Physiology and Metabolism, Faculty of Medicine, University of Geneva, Geneva 1211, Switzerland; Diabetes Center, Faculty of Medicine, University of Geneva, Geneva 1211, Switzerland; Institute of Genetics and Genomics in Geneva (iGE3), Geneva 1211, Switzerland
| | - Howard Riezman
- Department of Biochemistry, Faculty of Science, NCCR Chemical Biology, University of Geneva, Geneva 1211, Switzerland
| | - Charna Dibner
- Thoracic and Endocrine Surgery Division, Department of Surgery, University Hospital of Geneva, Geneva 1211, Switzerland; Department of Cell Physiology and Metabolism, Faculty of Medicine, University of Geneva, Geneva 1211, Switzerland; Diabetes Center, Faculty of Medicine, University of Geneva, Geneva 1211, Switzerland; Institute of Genetics and Genomics in Geneva (iGE3), Geneva 1211, Switzerland.
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3
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Huang A, Maier MT, Vagena E, Xu AW. Modulation of foraging-like behaviors by cholesterol-FGF19 axis. Cell Biosci 2023; 13:20. [PMID: 36732847 PMCID: PMC9893607 DOI: 10.1186/s13578-023-00955-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2022] [Accepted: 01/03/2023] [Indexed: 02/04/2023] Open
Abstract
BACKGROUND Foraging for food precedes food consumption and is an important component of the overall metabolic programming that regulates feeding. Foraging is governed by central nervous system neuronal circuits but how it is influenced by diet and hormonal signals is still not well understood. RESULTS In this study, we show that dietary cholesterol exerted suppressive effects on locomotor activity and that these effects were partially mediated by the neuropeptide Agouti-related protein (AgRP). High dietary cholesterol stimulated intestinal expression of fibroblast growth factor 15 (Fgf15), an ortholog of the human fibroblast growth factor 19 (FGF19). Intracerebroventricular infusion of FGF19 peptide reduced exploratory activity in the open field test paradigm. On the other hand, the lack of dietary cholesterol enhanced exploratory activity in the open field test, but this effect was abolished by central administration of FGF19. CONCLUSIONS Experiments in this study show that dietary cholesterol suppresses locomotor activity and foraging-like behaviors, and this regulation is in part mediated by AgRP neurons. Dietary cholesterol or the central action of FGF19 suppresses exploratory behaviors, and the anxiogenic effects of dietary cholesterol may be mediated by the effect of FGF19 in the mouse brain. This study suggests that dietary cholesterol and intestinal hormone FGF15/19 signal a satiating state to the brain, thereby suppressing foraging-like behaviors.
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Affiliation(s)
- Alyssa Huang
- Diabetes Center, University of California, San Francisco, CA, 94143, USA
| | - Matthew T Maier
- Diabetes Center, University of California, San Francisco, CA, 94143, USA
| | - Eirini Vagena
- Diabetes Center, University of California, San Francisco, CA, 94143, USA
| | - Allison W Xu
- Diabetes Center, University of California, San Francisco, CA, 94143, USA. .,Department of Anatomy, University of California, San Francisco, CA, 94143, USA.
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4
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Nelson NG, Wu L, Maier MT, Lam D, Cheang R, Alba D, Huang A, Neumann DA, Hill T, Vagena E, Barsh GS, Medina MW, Krauss RM, Koliwad SK, Xu AW. A gene-diet interaction controlling relative intake of dietary carbohydrates and fats. Mol Metab 2022; 58:101442. [PMID: 35051651 PMCID: PMC9710720 DOI: 10.1016/j.molmet.2022.101442] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/03/2021] [Revised: 01/04/2022] [Accepted: 01/10/2022] [Indexed: 12/15/2022] Open
Abstract
OBJECTIVE Preference for dietary fat vs. carbohydrate varies markedly across free-living individuals. It is recognized that food choice is under genetic and physiological regulation, and that the central melanocortin system is involved. However, how genetic and dietary factors interact to regulate relative macronutrient intake is not well understood. METHODS We investigated how the choice for food rich in carbohydrate vs. fat is influenced by dietary cholesterol availability and agouti-related protein (AGRP), the orexigenic component of the central melanocortin system. We assessed how macronutrient intake and different metabolic parameters correlate with plasma AGRP in a cohort of obese humans. We also examined how both dietary cholesterol levels and inhibiting de novo cholesterol synthesis affect carbohydrate and fat intake in mice, and how dietary cholesterol deficiency during the postnatal period impacts macronutrient intake patterns in adulthood. RESULTS In obese human subjects, plasma levels of AGRP correlated inversely with consumption of carbohydrates over fats. Moreover, AgRP-deficient mice preferred to consume more calories from carbohydrates than fats, more so when each diet lacked cholesterol. Intriguingly, inhibiting cholesterol biosynthesis (simvastatin) promoted carbohydrate intake at the expense of fat without altering total caloric consumption, an effect that was remarkably absent in AgRP-deficient mice. Finally, feeding lactating C57BL/6 dams and pups a cholesterol-free diet prior to weaning led the offspring to prefer fats over carbohydrates as adults, indicating that altered cholesterol metabolism early in life programs adaptive changes to macronutrient intake. CONCLUSIONS Together, our study illustrates a specific gene-diet interaction in modulating food choice.
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Affiliation(s)
- Nnamdi G. Nelson
- Diabetes Center, University of California, San Francisco, San Francisco,
CA 94143, USA
| | - Lili Wu
- Diabetes Center, University of California, San Francisco, San Francisco,
CA 94143, USA,Department of Integrated Medicine, Guangxi Medical University Cancer
Hospital, Nanning, Guangxi 530021, China
| | - Matthew T. Maier
- Diabetes Center, University of California, San Francisco, San Francisco,
CA 94143, USA
| | - Diana Lam
- Diabetes Center, University of California, San Francisco, San Francisco,
CA 94143, USA
| | - Rachel Cheang
- Diabetes Center, University of California, San Francisco, San Francisco,
CA 94143, USA
| | - Diana Alba
- Diabetes Center, University of California, San Francisco, San Francisco,
CA 94143, USA,Department of Medicine, University of California, San Francisco, San
Francisco, CA 94143, USA
| | - Alyssa Huang
- Diabetes Center, University of California, San Francisco, San Francisco,
CA 94143, USA,Department of Pediatrics, University of California, San Francisco, San
Francisco, CA 94143, USA
| | - Drexel A. Neumann
- Diabetes Center, University of California, San Francisco, San Francisco,
CA 94143, USA
| | - Tess Hill
- Diabetes Center, University of California, San Francisco, San Francisco,
CA 94143, USA
| | - Eirini Vagena
- Diabetes Center, University of California, San Francisco, San Francisco,
CA 94143, USA
| | - Gregory S. Barsh
- Department of Genetics, Stanford University School of Medicine, Stanford,
CA 94305, USA
| | - Marisa W. Medina
- Department of Pediatrics, University of California, San Francisco, San
Francisco, CA 94143, USA
| | - Ronald M. Krauss
- Department of Medicine, University of California, San Francisco, San
Francisco, CA 94143, USA,Department of Pediatrics, University of California, San Francisco, San
Francisco, CA 94143, USA
| | - Suneil K. Koliwad
- Diabetes Center, University of California, San Francisco, San Francisco,
CA 94143, USA,Department of Medicine, University of California, San Francisco, San
Francisco, CA 94143, USA,Corresponding author. Diabetes Center, University of California, San
Francisco, San Francisco, CA 94143, USA.
| | - Allison W. Xu
- Diabetes Center, University of California, San Francisco, San Francisco,
CA 94143, USA,Department of Anatomy, University of California, San Francisco, San
Francisco, CA 94143, USA,Corresponding author. Diabetes Center, University of California, San
Francisco, San Francisco, CA 94143, USA.
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5
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Tuning up an aged clock: Circadian clock regulation in metabolism and aging. TRANSLATIONAL MEDICINE OF AGING 2022. [DOI: 10.1016/j.tma.2021.11.003] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023] Open
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6
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Aqul AA, Ramirez CM, Lopez AM, Burns DK, Repa JJ, Turley SD. Molecular markers of brain cholesterol homeostasis are unchanged despite a smaller brain mass in a mouse model of cholesteryl ester storage disease. Lipids 2022; 57:3-16. [PMID: 34618372 PMCID: PMC8766890 DOI: 10.1002/lipd.12325] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2021] [Revised: 09/17/2021] [Accepted: 09/20/2021] [Indexed: 01/03/2023]
Abstract
Lysosomal acid lipase (LAL), encoded by the gene LIPA, facilitates the intracellular processing of lipids by hydrolyzing cholesteryl esters and triacylglycerols present in newly internalized lipoproteins. Loss-of-function mutations in LIPA result in cholesteryl ester storage disease (CESD) or Wolman disease when mutations cause complete loss of LAL activity. Although the phenotype of a mouse CESD model has been extensively characterized, there has not been a focus on the brain at different stages of disease progression. In the current studies, whole-brain mass and the concentrations of cholesterol in both the esterified (EC) and unesterified (UC) fractions were measured in Lal-/- and matching Lal+/+ mice (FVB-N strain) at ages ranging from 14 up to 280 days after birth. Compared to Lal+/+ controls at 50, 68-76, 140-142, and 230-280 days of age, Lal-/- mice had brain weights that averaged approximately 6%, 7%, 18%, and 20% less, respectively. Brain EC levels were higher in the Lal-/- mice at every age, being elevated 27-fold at 230-280 days. Brain UC concentrations did not show a genotypic difference at any age. The elevated brain EC levels in the Lal-/- mice did not reflect EC in residual blood. An mRNA expression analysis for an array of genes involved in the synthesis, catabolism, storage, and transport of cholesterol in the brains of 141-day old mice did not detect any genotypic differences although the relative mRNA levels for several markers of inflammation were moderately elevated in the Lal-/- mice. The possible sites of EC accretion in the central nervous system are discussed.
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Affiliation(s)
- Amal A. Aqul
- Department of Pediatrics, University of Texas Southwestern Medical Center, 5323 Harry Hines Blvd., Dallas TX 75390 USA
| | - Charina M. Ramirez
- Department of Pediatrics, University of Texas Southwestern Medical Center, 5323 Harry Hines Blvd., Dallas TX 75390 USA
| | - Adam M. Lopez
- Department of Internal Medicine, University of Texas Southwestern Medical Center, 5323 Harry Hines Blvd., Dallas TX 75390 USA
| | - Dennis K. Burns
- Department of Pathology, University of Texas Southwestern Medical Center, 5323 Harry Hines Blvd., Dallas TX 75390 USA
| | - Joyce J. Repa
- Department of Internal Medicine, University of Texas Southwestern Medical Center, 5323 Harry Hines Blvd., Dallas TX 75390 USA
- Department of Physiology, University of Texas Southwestern Medical Center, 5323 Harry Hines Blvd., Dallas TX 75390 USA
| | - Stephen D. Turley
- Department of Internal Medicine, University of Texas Southwestern Medical Center, 5323 Harry Hines Blvd., Dallas TX 75390 USA
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7
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Dong Y, Li X, Liu Y, Gao J, Tao J. The molecular targets of taurine confer anti-hyperlipidemic effects. Life Sci 2021; 278:119579. [PMID: 33961852 DOI: 10.1016/j.lfs.2021.119579] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2021] [Revised: 04/16/2021] [Accepted: 04/27/2021] [Indexed: 12/12/2022]
Abstract
Hyperlipidemia, an independent risk factor for atherosclerosis, is regarded as a lipid metabolism disorder associated with elevated plasma triglyceride and/or cholesterol. Genetic factors and unhealthy lifestyles, such as excess caloric intake and physical inactivity, can result in hyperlipidemia. Taurine, a sulfur-containing non-essential amino acid, is abundant in marine foods and has been associated with wide-ranging beneficial physiological effects, with special reference to regulating aberrant lipid metabolism. Its anti-hyperlipidemic mechanism is complex, which is related to many enzymes in the process of fat anabolism and catabolism (e.g., HMGCR, CYP7A1, LDLR, FXR, FAS and ACC). Anti-inflammatory and antioxidant molecular targets, lipid autophagy, metabolic reprogramming and gut microbiota will also be reviewed.
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Affiliation(s)
- Yuanyuan Dong
- Department of Rheumatology and Immunology, the First Affiliated Hospital of USTC, China; Division of Life Sciences and Medicine, University of Science and Technology of China, No. 17 LuJiang Road, Hefei 230001, Anhui, China
| | - Xiaoling Li
- Department of Rheumatology and Immunology, the First Affiliated Hospital of USTC, China; Division of Life Sciences and Medicine, University of Science and Technology of China, No. 17 LuJiang Road, Hefei 230001, Anhui, China
| | - Yaling Liu
- Department of Rheumatology and Immunology, the First Affiliated Hospital of USTC, China; Division of Life Sciences and Medicine, University of Science and Technology of China, No. 17 LuJiang Road, Hefei 230001, Anhui, China
| | - Jie Gao
- Department of Rheumatology and Immunology, the First Affiliated Hospital of USTC, China; Division of Life Sciences and Medicine, University of Science and Technology of China, No. 17 LuJiang Road, Hefei 230001, Anhui, China
| | - Jinhui Tao
- Department of Rheumatology and Immunology, the First Affiliated Hospital of USTC, China; Division of Life Sciences and Medicine, University of Science and Technology of China, No. 17 LuJiang Road, Hefei 230001, Anhui, China.
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8
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Ramirez CM, Taylor AM, Lopez AM, Repa JJ, Turley SD. Delineation of metabolic responses of Npc1 -/-nih mice lacking the cholesterol-esterifying enzyme SOAT2 to acute treatment with 2-hydroxypropyl-β-cyclodextrin. Steroids 2020; 164:108725. [PMID: 32890578 PMCID: PMC7680374 DOI: 10.1016/j.steroids.2020.108725] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/08/2020] [Revised: 08/14/2020] [Accepted: 08/25/2020] [Indexed: 12/26/2022]
Abstract
Lipids present in lipoproteins cleared from the circulation are processed sequentially by three major proteins within the late endosomal/lysosomal (E/L) compartment of all cells: lysosomal acid lipase (LAL), Niemann-Pick (NPC) C2 and NPC1. When all three of these proteins are functioning normally, unesterified cholesterol (UC) exits the E/L compartment and is used in plasma membrane maintenance and various pathways in the endoplasmic reticulum including esterification by sterol O-acyltransferase 2 (SOAT2) or SOAT1 depending partly on cell type. Mutations in either NPC2 or NPC1 result in continual entrapment of UC and glycosphingolipids leading to neurodegeneration, pulmonary dysfunction, splenomegaly and liver damage. To date, the most effective agent for promoting release of entrapped UC in nearly all organs of NPC1-deficient mice and cats is 2-hydroxypropyl-β-cyclodextrin (2HPβCD). The cytotoxic nature of the liberated UC triggers various defenses including suppression of sterol synthesis and increased esterification. The present studies, using the Npc1-/-nih mouse model, measured the comparative quantitative importance of these two responses in the liver versus the spleen of Npc1-/-: Soat2+/+ and Npc1-/-: Soat2-/- mice in the 24 h following a single acute treatment with 2HPβCD. In the liver but not the spleen of both types of mice suppression of synthesis alone or in combination with increased esterification provided the major defense against the rise in unsequestered cellular UC content. These findings have implications for systemic 2HPβCD treatment in NPC1 patients in view of the purportedly low levels of SOAT2 activity in human liver.
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Affiliation(s)
- Charina M Ramirez
- Department of Pediatrics, University of Texas Southwestern Medical Center, Dallas, TX, USA
| | - Anna M Taylor
- Department of Physiology, University of Texas Southwestern Medical Center, Dallas, TX, USA
| | - Adam M Lopez
- Department of Internal Medicine, University of Texas Southwestern Medical Center, Dallas, TX, USA
| | - Joyce J Repa
- Department of Physiology, University of Texas Southwestern Medical Center, Dallas, TX, USA; Department of Internal Medicine, University of Texas Southwestern Medical Center, Dallas, TX, USA
| | - Stephen D Turley
- Department of Internal Medicine, University of Texas Southwestern Medical Center, Dallas, TX, USA.
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9
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Wang J, Wang F, Yuan L, Wu Y, Peng X, Kai G, Zhu S, Liu Y. Aqueous extracts of Lindera aggregate (Sims) Kosterm leaves regulate serum/hepatic lipid and liver function in normal and hypercholesterolemic mice. J Pharmacol Sci 2020; 143:45-51. [PMID: 32169433 DOI: 10.1016/j.jphs.2020.01.009] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2019] [Revised: 01/01/2020] [Accepted: 01/21/2020] [Indexed: 02/06/2023] Open
Abstract
The leaves of Lindera aggregate (Sims) Kosterm. are traditionally used as healthy tea for the prevention and treatment of hyperlipidemia in Chinese. The aim of this study was to evaluate the antihyperlipidemic effects and potential mechanisms of the aqueous extracts from L. aggregate leaves (AqLA-L) on normal and hypercholesterolemic (HCL) mice. HCL mice were induced by high fat diet (HFD) and orally administrated with or without AqLA-L for ten days. The results showed that AqLA-L (0.3, 0.6, 1.2 g/kg) significantly reduced serum TG, ALT, but elevated fecal TG in normal mice. AqLA-L (0.3, 0.6, 1.2 g/kg) also remarkably lowered serum TC, TG, LDL, N-HDL, ALT, GLU, APOB, hepatic GLU and increased serum HDL, APOA-I, fecal TG levels in HCL mice. These results revealed that AqLA-L treatment regulated the disorders of the serum lipid and liver function, reduced hepatic GLU contents both in normal and HCL mice. The potential mechanisms for cholesterol-lowering effects of AqLA-L might be up-regulation of cholesterol 7-alpha-hydroxylase (CYP7A1) and ATP-binding cassette transporter A1 (ABCA1), as well as down-regulation of 3-hydroxy-3-methylglutaryl CoA reductase (HMGCR). The data indicated that AqLA-L has potential therapeutic value in treatment of hyperlipidemia with great application security.
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Affiliation(s)
- Juan Wang
- Institute of Biopharmaceutical, Zhejiang Pharmaceutical College, Zhejiang Province, Ningbo 315100, PR China
| | - Furong Wang
- Institute of Biopharmaceutical, Zhejiang Pharmaceutical College, Zhejiang Province, Ningbo 315100, PR China
| | - Lixia Yuan
- Institute of Biopharmaceutical, Zhejiang Pharmaceutical College, Zhejiang Province, Ningbo 315100, PR China
| | - Yao Wu
- Institute of Biopharmaceutical, Zhejiang Pharmaceutical College, Zhejiang Province, Ningbo 315100, PR China
| | - Xin Peng
- Institute of Biopharmaceutical, Zhejiang Pharmaceutical College, Zhejiang Province, Ningbo 315100, PR China.
| | - Guoyin Kai
- Zhejiang Chinese Medical University, Zhejiang Province, Hangzhou 311400, PR China
| | - ShaoFeng Zhu
- Institute of Biopharmaceutical, Zhejiang Pharmaceutical College, Zhejiang Province, Ningbo 315100, PR China
| | - Yugang Liu
- Institute of Biopharmaceutical, Zhejiang Pharmaceutical College, Zhejiang Province, Ningbo 315100, PR China
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10
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Wang SH, Wang WW, Zhang HJ, Wang J, Chen Y, Wu SG, Qi GH. Conjugated linoleic acid regulates lipid metabolism through the expression of selected hepatic genes in laying hens. Poult Sci 2019; 98:4632-4639. [PMID: 30951597 DOI: 10.3382/ps/pez161] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2018] [Accepted: 03/12/2019] [Indexed: 01/09/2023] Open
Abstract
The effect of dietary conjugated linoleic acid (CLA) supplementation on lipid metabolism in laying hens was investigated. A total of 360 eighteen-wk-old Hy-Line Brown layers were randomly divided into 4 groups that consisted of 6 replicates with 15 birds each. Birds were fed basal diets with 0, 1%, 2%, and 4% CLA addition. The experiment lasted for 56 D after a 7-D adaptation period. Results showed that dietary CLA addition linearly reduced (P < 0.05) abdominal fat percentage but linearly increased (P < 0.05) relative liver weight of layers on day 56. A linear reduction (P < 0.05) in serum low-density lipoprotein cholesterol (LDL-C) level and a linear elevation (P < 0.05) in the ratio of serum high-density lipoprotein cholesterol level to LDL-C level of layers on both days 28 and 56 were observed with dietary CLA addition, which also linearly decreased (P < 0.05) cholesterol content in the liver of layers on day 56 as well as in eggs on both days 28 and 56. Besides, there were linear reductions (P < 0.05) in the gene expression and contents of hepatic 3-hydroxy-3-methylglutaryl coenzyme A reductase (HMGR) and cholesterol 7 alpha hydroxylase 1 (CYP7A1), along with a linear increase (P < 0.05) in the gene expression and content of hepatic low-density lipoprotein receptor (LDLR) in layers responded to dietary CLA addition. In conclusion, dietary CLA supplementation decreased the accumulation of lipids including abdominal fat and cholesterol in the liver and egg of laying hens, probably by upregulating hepatic LDLR expression and downregulating hepatic HMGR and CYP7A1 expression.
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Affiliation(s)
- Sheng-Hui Wang
- Key Laboratory of Feed Biotechnology, Ministry of Agriculture and Rural Affairs, National Engineering Research Center of Biological Feed, Feed Research Institute, Chinese Academy of Agricultural Sciences, Beijing 100081, P. R. China
| | - Wei-Wei Wang
- Key Laboratory of Feed Biotechnology, Ministry of Agriculture and Rural Affairs, National Engineering Research Center of Biological Feed, Feed Research Institute, Chinese Academy of Agricultural Sciences, Beijing 100081, P. R. China
| | - Hai-Jun Zhang
- Key Laboratory of Feed Biotechnology, Ministry of Agriculture and Rural Affairs, National Engineering Research Center of Biological Feed, Feed Research Institute, Chinese Academy of Agricultural Sciences, Beijing 100081, P. R. China
| | - Jing Wang
- Key Laboratory of Feed Biotechnology, Ministry of Agriculture and Rural Affairs, National Engineering Research Center of Biological Feed, Feed Research Institute, Chinese Academy of Agricultural Sciences, Beijing 100081, P. R. China
| | - Yu Chen
- Beijing Stockbreeding Station, Beijing 100026, P. R. China
| | - Shu-Geng Wu
- Key Laboratory of Feed Biotechnology, Ministry of Agriculture and Rural Affairs, National Engineering Research Center of Biological Feed, Feed Research Institute, Chinese Academy of Agricultural Sciences, Beijing 100081, P. R. China
| | - Guang-Hai Qi
- Key Laboratory of Feed Biotechnology, Ministry of Agriculture and Rural Affairs, National Engineering Research Center of Biological Feed, Feed Research Institute, Chinese Academy of Agricultural Sciences, Beijing 100081, P. R. China
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11
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Ceres K, Fitzgerald H, Quiznon KS, McDonough S, Behling-Kelly E. Immunohistochemical Labeling of Low-Density Lipoprotein Receptor and Scavenger Receptor Class B Type 1 Are Increased in Canine Lymphoma. Front Vet Sci 2019; 5:340. [PMID: 30687727 PMCID: PMC6336922 DOI: 10.3389/fvets.2018.00340] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2018] [Accepted: 12/18/2018] [Indexed: 12/11/2022] Open
Abstract
Altered lipid metabolism is a well-documented hallmark of neoplastic transformation and impacts disease progression. Two major lipoprotein receptors, the low-density lipoprotein receptor (LDL-R) and scavenger receptor class B, type 1 (SR-BI) are overexpressed in a number of cancer types in people. These receptors serve to deliver cholesterol to the tumor cells and have been used to target drug therapies. In this study, we performed a retrospective analysis of LDL-R and SR-B1 expression in canine lymphoma using archived formalin-fixed tissue samples. Cases were immunophenotyped and classified according to World Health Organization (WHO) standards prior to immunostaining for the LDL_R and SR-B1. A total of 45 cases were evaluated; 21 high grade B (HGB), 11 low grade B (LGB), 7 high grade T (HGT), and 6 low grade T (LGT) lymphomas. One sided Wilcoxon rank sum tests were used to compare staining intensity between neoplastic and hyperplastic lymphoid tissue. The relationships between histological score and tumor grade and score and stage at presentation were assessed using non-parametric Kruskal-Wallis tests. Neoplastic lymphoid tissue expressed higher levels of both receptors compared to reactive lymph nodes. Median LDL-R score was 85.0 (interquartile range = 101.7), Median SR-B1 score was 209.0 (interquartile range 105.2). No relationship between LDL-R or SR-B1 staining score and tumor grade or phenotype was found. Serum cholesterol concentration was compared between dogs with high and low grade tumors using a two sample T-test, and correlations between cholesterol concentration and histological score, and between the score for the two receptors were determined using a Spearman correlation. The high expression level of these lipoprotein receptors on most of the tumors could underlie the lack of relationship between score and tumor grade. The overexpression of LDL-R and SR-B1 in canine lymphoma holds therapeutic potential particularly in dogs that overexpress one or both of these receptors, and this warrants further investigation.
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Affiliation(s)
- Kristina Ceres
- Department of Population Medicine and Diagnostic Services, College of Veterinary Medicine, Cornell University, Ithaca, NY, United States
| | - Halle Fitzgerald
- College of Agriculture and Life Sciences, Cornell University, Ithaca, NY, United States
| | | | - Sean McDonough
- Department of Biomedical Sciences, College of Veterinary Medicine, Cornell University, Ithaca, NY, United States
| | - Erica Behling-Kelly
- Department of Population Medicine and Diagnostic Services, College of Veterinary Medicine, Cornell University, Ithaca, NY, United States
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12
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Lütjohann D, Lopez AM, Chuang JC, Kerksiek A, Turley SD. Identification of Correlative Shifts in Indices of Brain Cholesterol Metabolism in the C57BL6/Mecp2 tm1.1Bird Mouse, a Model for Rett Syndrome. Lipids 2018; 53:363-373. [PMID: 29770459 DOI: 10.1002/lipd.12041] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2017] [Revised: 02/26/2018] [Accepted: 04/03/2018] [Indexed: 01/14/2023]
Abstract
Rett syndrome (RS) is a pervasive neurodevelopmental disorder resulting from loss-of-function mutations in the X-linked gene methyl-Cpg-binding protein 2 (MECP2). Using a well-defined model for RS, the C57BL6/Mecp2tm1.1Bird mouse, we have previously found a moderate but persistently lower rate of cholesterol synthesis, measured in vivo, in the brains of Mecp2-/y mice, starting from about the third week after birth. There was no genotypic difference in the total cholesterol concentration throughout the brain at any age. This raised the question of whether the lower rate of cholesterol synthesis in the mutants was balanced by a fall in the rate at which cholesterol was converted via cholesterol 24-hydroxylase (Cyp46A1) to 24S-hydroxycholesterol (24S-OHC), the principal route through which cholesterol is ordinarily removed from the brain. Here, we show that while there were no genotypic differences in the concentrations in plasma and liver of three cholesterol precursors (lanosterol, lathosterol, and desmosterol), two plant sterols (sitosterol and campesterol), and two oxysterols (27-hydroxycholesterol [27-OHC] and 24S-OHC), the brains of the Mecp2 -/y mice had significantly lower concentrations of all three cholesterol precursors, campesterol, and both oxysterols, with the level of 24S-OHC being ~20% less than in their Mecp2 +/y controls. Together, these data suggest that coordinated regulation of cholesterol synthesis and catabolism in the central nervous system is maintained in this model for RS. Furthermore, we speculate that the adaptive changes in these two pathways conceivably resulted from a shift in the permeability of the blood-brain barrier as implied by the significantly lower campesterol and 27-OHC concentrations in the brains of the Mecp2-/y mice.
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Affiliation(s)
- Dieter Lütjohann
- Institute for Clinical Chemistry and Clinical Pharmacology, University Clinics of Bonn, Sigmund-Freud-Str. 25, 53127 Bonn, Germany
| | - Adam M Lopez
- Department of Internal Medicine, University of Texas Southwestern Medical Center, 5323 Harry Hines Blvd., Dallas, TX 75390-9151, USA
| | - Jen-Chieh Chuang
- Children's Medical Center Research Institute, University of Texas Southwestern Medical Center, 6000 Harry Hines Blvd., Dallas, TX 75390-9060, USA
| | - Anja Kerksiek
- Institute for Clinical Chemistry and Clinical Pharmacology, University Clinics of Bonn, Sigmund-Freud-Str. 25, 53127 Bonn, Germany
| | - Stephen D Turley
- Department of Internal Medicine, University of Texas Southwestern Medical Center, 5323 Harry Hines Blvd., Dallas, TX 75390-9151, USA
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13
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Fan W, Zhang XL, Shi P, Li J, Wang CZ, Li DF, Zhu XY. Effects of dietary alfalfa saponins on laying performance, egg cholesterol concentration, and ATP-binding cassette transporters G5 and G8 expression in laying hens. JOURNAL OF APPLIED ANIMAL RESEARCH 2018. [DOI: 10.1080/09712119.2018.1454323] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Affiliation(s)
- Wenna Fan
- Animal Science and Technology College, Henan University of Science and Technology, Luoyang, People’s Republic of China
| | - Xian-lei Zhang
- College of Animal Science and Veterinary Medicine, Henan Agricultural University, Zhengzhou, People’s Republic of China
| | - Pengfei Shi
- Animal Science and Technology College, Henan University of Science and Technology, Luoyang, People’s Republic of China
| | - Jia Li
- College of Animal Science and Veterinary Medicine, Henan Agricultural University, Zhengzhou, People’s Republic of China
| | - Cheng-zhang Wang
- College of Animal Science and Veterinary Medicine, Henan Agricultural University, Zhengzhou, People’s Republic of China
| | - De-feng Li
- College of Animal Science and Veterinary Medicine, Henan Agricultural University, Zhengzhou, People’s Republic of China
| | - Xiao-yan Zhu
- College of Animal Science and Veterinary Medicine, Henan Agricultural University, Zhengzhou, People’s Republic of China
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14
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Li ZJ, Abulizi A, Zhao GL, Wang T, Zhou F, Jiang ZZ, Aibai S, Zhang LY. Bakuchiol Contributes to the Hepatotoxicity of Psoralea corylifolia in Rats. Phytother Res 2017. [PMID: 28639266 DOI: 10.1002/ptr.5851] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Psoralea corylifolia L. (Fructus Psoraleae) is widely used in Asia, but there are concerns about hepatotoxicity caused by constituents such as psoralens and bakukiol. Bakuchiol (BAK) has antiinflammatory, antipyretic, antibacterial antiviral, anticancer, and estrogenic activity but appears to be hepatotoxic in in vitro tests. This study investigated the hepatotoxicity in vivo in rats. Using intragastrically administered bakuchiol at doses of 52.5 and 262.5 mg/kg for 6 weeks. Bodyweight, relative liver weight, biochemical indicators, histopathology, mRNA expression of CYP7A1, HMG-CoA reductase, BSEP, PPARα, SREBP-2, and MRP3 were measured. Many abnormalities were observed in the bakuchiol-treated groups including suppression of weight gain and food intake, change of some parameters in serum biochemistry, and increased weight of liver. The mRNA expression of CYP7A1, HMG-CoA reductase, PPARα, and SREBP-2 decreased in bakuchiol-treated group, the expression of BSEP increased in bakuchiol-treated low dosage, and the expression of BSEP decreased in bakuchiol-treated high dosage. In conclusion, we provide evidence for the first time that bakuchiol can induce cholestatic hepatotoxicity, suggesting potential hepatotoxicity. The mechanism may be related to effects on liver lipid metabolism, but further investigation is necessary. Copyright © 2017 John Wiley & Sons, Ltd.
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Affiliation(s)
- Zhi-Jian Li
- Jiangsu Key Laboratory of Drug Screening, China Pharmaceutical University, Nanjing, Jiangsu, 210009, China.,Department of Toxicology Laboratory Xinjiang Institute of Traditional Uyghur Medicine, Xinjiang Laboratory of Uyghur Medical Prescription, Urumqi, Xinjiang, 830049, China
| | - Abudumijiti Abulizi
- Basic Medical College, Xinjiang Medical University, Xinjiang Uyghur Autonomous Region, Urumqi, 830054, China
| | - Guo-Lin Zhao
- Jiangsu Key Laboratory of Drug Screening, China Pharmaceutical University, Nanjing, Jiangsu, 210009, China
| | - Tao Wang
- Jiangsu Key Laboratory of Drug Screening, China Pharmaceutical University, Nanjing, Jiangsu, 210009, China
| | - Fan Zhou
- Xinjiang Huashidan Pharmaceutical Research Co., Ltd, Urumqi, Xinjiang, 830011, China
| | - Zhen-Zhou Jiang
- Jiangsu Key Laboratory of Drug Screening, China Pharmaceutical University, Nanjing, Jiangsu, 210009, China
| | - Silafu Aibai
- Department of Toxicology Laboratory Xinjiang Institute of Traditional Uyghur Medicine, Xinjiang Laboratory of Uyghur Medical Prescription, Urumqi, Xinjiang, 830049, China
| | - Lu-Yong Zhang
- Jiangsu Key Laboratory of Drug Screening, China Pharmaceutical University, Nanjing, Jiangsu, 210009, China
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15
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Li WK, Li H, Lu YF, Li YY, Fu ZD, Liu J. Atorvastatin alters the expression of genes related to bile acid metabolism and circadian clock in livers of mice. PeerJ 2017; 5:e3348. [PMID: 28533986 PMCID: PMC5438592 DOI: 10.7717/peerj.3348] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2017] [Accepted: 04/23/2017] [Indexed: 02/06/2023] Open
Abstract
Aim Atorvastatin is a HMG-CoA reductase inhibitor used for hyperlipidemia. Atorvastatin is generally safe but may induce cholestasis. The present study aimed to examine the effects of atorvastatin on hepatic gene expression related to bile acid metabolism and homeostasis, as well as the expression of circadian clock genes in livers of mice. Methods Adult male mice were given atorvastatin (10, 30, and 100 mg/kg, po) daily for 30 days, and blood biochemistry, histopathology, and gene expression were examined. Results Repeated administration of atorvastatin did not affect animal body weight gain or liver weights. Serum enzyme activities were in the normal range. Histologically, the high dose of atorvastatin produced scattered swollen hepatocytes, foci of feathery-like degeneration, together with increased expression of Egr-1 and metallothionein-1. Atorvastatin increased the expression of Cyp7a1 in the liver, along with FXR and SHP. In contract, atorvastatin decreased the expression of bile acid transporters Ntcp, Bsep, Ostα, and Ostβ. The most dramatic change was the 30-fold induction of Cyp7a1. Because Cyp7a1 is a circadian clock-controlled gene, we further examined the effect of atorvastatin on clock gene expression. Atorvastatin increased the expression of clock core master genes Bmal1 and Npas2, decreased the expression of clock feedback genes Per2, Per3, and the clock targeted genes Dbp and Tef, whereas it had no effect on Cry1 and Nr1d1 expression. Conclusion Repeated administration of atorvastatin affects bile acid metabolism and markedly increases the expression of the bile acid synthesis rate-limiting enzyme gene Cyp7a1, together with alterations in the expression of circadian clock genes.
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Affiliation(s)
- Wen-Kai Li
- Key Lab for Basic Pharmacology of Ministry of Education and Joint International Research Laboratory of Ethnomedicine of Ministry of Education, Zunyi Medical College, Zunyi, China.,Department of Pharmacology, Shanghai University of Chinese Traditional Medicine, Shanghai, China
| | - Huan Li
- Key Lab for Basic Pharmacology of Ministry of Education and Joint International Research Laboratory of Ethnomedicine of Ministry of Education, Zunyi Medical College, Zunyi, China
| | - Yuan-Fu Lu
- Key Lab for Basic Pharmacology of Ministry of Education and Joint International Research Laboratory of Ethnomedicine of Ministry of Education, Zunyi Medical College, Zunyi, China
| | - Ying-Ying Li
- Key Lab for Basic Pharmacology of Ministry of Education and Joint International Research Laboratory of Ethnomedicine of Ministry of Education, Zunyi Medical College, Zunyi, China
| | - Zidong Donna Fu
- Department of Environmental and Occupational Health Sciences, University of Washington, Seattle, WA, United States of America
| | - Jie Liu
- Key Lab for Basic Pharmacology of Ministry of Education and Joint International Research Laboratory of Ethnomedicine of Ministry of Education, Zunyi Medical College, Zunyi, China
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16
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Lopez AM, Chuang JC, Turley SD. Measurement of Rates of Cholesterol and Fatty Acid Synthesis In Vivo Using Tritiated Water. Methods Mol Biol 2017; 1583:241-256. [PMID: 28205179 DOI: 10.1007/978-1-4939-6875-6_18] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
Every organ in the body is capable of synthesizing cholesterol de novo but at rates that vary with a constellation of factors. A significant proportion of the hydrogen atoms present in cholesterol that is synthesized in the body are derived from water. Thus, although water ordinarily makes up the bulk of body mass, the acute enrichment of the body water pool with a sufficiently large amount of tritiated water over a short interval of time (usually 1 h) yields measurable rates of incorporation of the labeled water into newly generated cholesterol and also fatty acids. Such data can provide a quantitative measure of how specific genetic, dietary, and pharmacological manipulations impact not just the rate of cholesterol synthesis in particular organs but also rates of whole-body cholesterol production and turnover.
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Affiliation(s)
- Adam M Lopez
- Division of Digestive and Liver Diseases, Department of Internal Medicine, University of Texas Southwestern Medical Center, 5323 Harry Hines Blvd., Dallas, TX, 75390-9151, USA
| | - Jen-Chieh Chuang
- Division of Digestive and Liver Diseases, Department of Internal Medicine, University of Texas Southwestern Medical Center, 5323 Harry Hines Blvd., Dallas, TX, 75390-9151, USA
| | - Stephen D Turley
- Division of Digestive and Liver Diseases, Department of Internal Medicine, University of Texas Southwestern Medical Center, 5323 Harry Hines Blvd., Dallas, TX, 75390-9151, USA.
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17
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Kolbe I, Husse J, Salinas G, Lingner T, Astiz M, Oster H. The SCN Clock Governs Circadian Transcription Rhythms in Murine Epididymal White Adipose Tissue. J Biol Rhythms 2016; 31:577-587. [PMID: 27650461 DOI: 10.1177/0748730416666170] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
The circadian master pacemaker in the suprachiasmatic nucleus (SCN) orchestrates peripheral clocks in various organs and synchronizes them with external time, including those in adipose tissue, which displays circadian oscillations in various metabolic and endocrine outputs. Because our knowledge about the instructive role of the SCN clock on peripheral tissue function is based mainly on SCN lesion studies, we here used an alternative strategy employing the Cre/ loxP system to functionally delete the SCN clock in mice. We performed whole-genome microarray hybridizations of murine epididymal white adipose tissue (eWAT) RNA preparations to characterize the role of the SCN clock in eWAT circadian transcriptome regulation. Most of the rhythmic transcripts in control animals were not rhythmic in SCN mutants, but a significant number of transcripts were rhythmic only in mutant eWAT. Core clock genes were rhythmic in both groups, but as was reported before for other tissues, rhythms were dampened and phase advanced in mutant animals. In SCN-mutant mice, eWAT lost the rhythm of metabolic pathway-related transcripts, while transcripts gaining rhythms in SCN-mutant mice were associated with various immune functions. These data reveal a complex interaction of SCN-derived and local circadian signals in the regulation of adipose transcriptome programs.
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Affiliation(s)
- Isa Kolbe
- Chronophysiology Group, Medical Department 1, University of Lübeck, Lübeck, Germany
| | - Jana Husse
- Program in Neurosciences and Mental Health, The Hospital for Sick Children, Toronto, Ontario, Canada
| | - Gabriela Salinas
- Microarray and Deep-Sequencing Core Facility, Institute Developmental Biochemistry, University Medical Center, Göttingen, Germany
| | - Thomas Lingner
- Microarray and Deep-Sequencing Core Facility, Institute Developmental Biochemistry, University Medical Center, Göttingen, Germany
| | - Mariana Astiz
- Chronophysiology Group, Medical Department 1, University of Lübeck, Lübeck, Germany
| | - Henrik Oster
- Chronophysiology Group, Medical Department 1, University of Lübeck, Lübeck, Germany
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18
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Lopez AM, Chuang JC, Posey KS, Turley SD. Suppression of brain cholesterol synthesis in male Mecp2-deficient mice is age dependent and not accompanied by a concurrent change in the rate of fatty acid synthesis. Brain Res 2016; 1654:77-84. [PMID: 27789278 DOI: 10.1016/j.brainres.2016.10.021] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2016] [Revised: 10/13/2016] [Accepted: 10/21/2016] [Indexed: 12/29/2022]
Abstract
Mutations in the X-linked gene methyl-CpG-binding protein 2 (MECP2) are the principal cause of Rett syndrome, a progressive neurodevelopmental disorder afflicting 1 in 10,000 to 15,000 females. Studies using hemizygous Mecp2 mouse models have revealed disruptions to some aspects of their lipid metabolism including a partial suppression of cholesterol synthesis in the brains of mature Mecp2 mutants. The present studies investigated whether this suppression is evident from early neonatal life, or becomes manifest at a later stage of development. We measured the rate of cholesterol synthesis, in vivo, in the brains of male Mecp2-/y and their Mecp2+/y littermates at 7, 14, 21, 28, 42 and 56 days of age. Brain weight was consistently lower in the Mecp2-/y mice than in their Mecp2+/y controls except at 7 days of age. In the 7- and 14-day-old mice there was no genotypic difference in the rate of brain cholesterol synthesis but, from 21 days and later, it was always marginally lower in the Mecp2-/y mice than in age-matched Mecp2+/y littermates. At no age was a genotypic difference detected in either the rate of fatty acid synthesis or cholesterol concentration in the brain. Cholesterol synthesis rates in the liver and lungs of 56-day-old Mecp2-/y mice were normal. The onset of lower rates of brain cholesterol synthesis at about the time closure of the blood brain barrier purportedly occurs might signify a disruption to mechanism(s) that dictate intracellular levels of cholesterol metabolites including oxysterols known to exert a regulatory influence on the cholesterol biosynthetic pathway.
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Affiliation(s)
- Adam M Lopez
- Department of Internal Medicine, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA.
| | - Jen-Chieh Chuang
- Children's Research Institute, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA.
| | - Kenneth S Posey
- Department of Internal Medicine, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA.
| | - Stephen D Turley
- Department of Internal Medicine, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA.
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19
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Ellis M, Krashin E, Hamburger-Avnery O, Gan S, Elis A, Ashur-Fabian O. The anti-leukemic and lipid lowering effects of imatinib are not hindered by statins in CML: a retrospective clinical study and in vitro assessment of lipid-genes transcription. Leuk Lymphoma 2016; 58:1172-1177. [PMID: 27650030 DOI: 10.1080/10428194.2016.1228928] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
Abstract
Imatinib, which has revolutionized chronic myeloid leukemia (CML) treatment, was suggested to improve lipid profile. Statins, a dyslipidemia drug, were reported to potentiate imatinib's antileukemic effect. However, analysis of imatinib combined with statins is lacking. We have retrospectively analyzed the normalization period of bcr-abl, blood counts, and lipids in 40 CML patients, 19 of which co-treated with statins, during short (<12 months) and prolonged (>12 months) imatinib treatment. Prior statins treatment did not hinder nor sensitized imatinib's anti-leukemic and lipid-lowering effects. CML cells (K562) treated with 1μM imatinib (24-96 h) were further assessed for the expression of central lipid-related genes by real-time PCR. HMGCoAR, LDL-R, and apobec1 expressions were significantly increased while CETP declined after 48-96 h. To conclude, imatinib produces an independent favorable lipid profile, which is not hindered by statins and is partly mediated via transcription regulation of genes involved in the clearance of plasma lipids.
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Affiliation(s)
- Martin Ellis
- a Translational Hemato-Oncology Laboratory , Hematology Institute and Blood Bank, Meir Medical Center , Kfar-Saba , Israel.,b Sackler Faculty of Medicine , Tel Aviv University , Tel Aviv , Israel
| | - Eilon Krashin
- c Department of Internal Medicine A , Meir Medical Center , Kfar-Saba , Israel
| | - Orly Hamburger-Avnery
- a Translational Hemato-Oncology Laboratory , Hematology Institute and Blood Bank, Meir Medical Center , Kfar-Saba , Israel
| | - Sarah Gan
- a Translational Hemato-Oncology Laboratory , Hematology Institute and Blood Bank, Meir Medical Center , Kfar-Saba , Israel.,b Sackler Faculty of Medicine , Tel Aviv University , Tel Aviv , Israel
| | - Avishai Elis
- b Sackler Faculty of Medicine , Tel Aviv University , Tel Aviv , Israel.,d Department of Internal Medicine C , Beilinson Campus, Rabin Medical Center , Petah Tikva , Israel
| | - Osnat Ashur-Fabian
- a Translational Hemato-Oncology Laboratory , Hematology Institute and Blood Bank, Meir Medical Center , Kfar-Saba , Israel.,e The Department of Human Molecular Genetics and Biochemistry, Sackler Faculty of Medicine , Tel Aviv University , Tel Aviv , Israel
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20
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Jiang C, Wang Q, Wei Y, Yao N, Wu Z, Ma Y, Lin Z, Zhao M, Che C, Yao X, Zhang J, Yin Z. Cholesterol-lowering effects and potential mechanisms of different polar extracts from Cyclocarya paliurus leave in hyperlipidemic mice. JOURNAL OF ETHNOPHARMACOLOGY 2015; 176:17-26. [PMID: 26477373 DOI: 10.1016/j.jep.2015.10.006] [Citation(s) in RCA: 70] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/03/2015] [Revised: 08/27/2015] [Accepted: 10/02/2015] [Indexed: 05/06/2023]
Abstract
ETHNOPHARMACOLOGICAL RELEVANCE Cyclocarya paliurus Batal., native only to China, is widely consumed as a Chinese traditional folk medicine for the prevention and treatment of hyperlipidemia, obesity, and diabetes. The aim of the study is to investigate the cholesterol-lowering effect and potential mechanisms of different polar extracts from Cyclocarya paliurus leaves in mice fed with high-fat-diet. MATERIALS AND METHODS Cyclocarya paliurus leaves extracts were orally administered to diet-induced hyperlipidemic mice for 4 weeks. Simvastatin was used as a positive control. Body weight, food intake, histopathology of liver and adipose tissues, hepatic and renal function indices, lipid profiles in the serum and liver were evaluated. Total bile acid concentrations of the liver and feces were also measured. Furthermore, the activities and mRNA expression of cholesterol metabolism-related enzymes including 3-hydroxy-3-methylglutaryl-coenzyme A (HMG-CoA) reductase, cholesterol 7α-hydroxylase (CYP7A1) and acyl-CoA cholesterol acyltransferase 2 (ACAT2) in the livers of the mice were analyzed. LC-MS detection was performed to identify the components in the active fraction of Cyclocarya paliurus extracts. RESULTS Different Cyclocarya paliurus polar extracts, especially ChE reduced the levels of serum total cholesterol (TC), triglycerides (TG), low-density lipoprotein cholesterol (LDL-C) and hepatic TC and TG, enhanced the level of serum high-density lipoprotein cholesterol (HDL-C), restored hepatic and renal function indices and histomorphology. HMG-CoA reductase activity and mRNA expression were decreased, while CYP7A1 activity and mRNA expression as well as the level of fecal and hepatic bile acid were increased by ChE. LC-MS analysis of ChE revealed the presence of six main triterpenoids, which might be responsible for its antihyperlipidemic bioactivity. CONCLUSIONS Evidently ChE possesses the best antihyperlipidemic activity, and the cholesterol-lowering effect is at least partly attributed to its role in promoting the conversion of cholesterol into bile acids by upgrading the activity and mRNA expression of CYP7A1 and inhibiting those of HMG-CoA reductase to lower the cholesterol biosynthesis.
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Affiliation(s)
- Cuihua Jiang
- Laboratory of Translational Medicine, Jiangsu Province Academy of Traditional Chinese Medicine, Nanjing 210028, Jiangsu Province, PR China; Department of Natural Medicinal Chemistry & State Key Laboratory of Natural Medicines, China Pharmaceutical University, Nanjing 210009, Jiangsu Province, PR China
| | - Qingqing Wang
- Laboratory of Translational Medicine, Jiangsu Province Academy of Traditional Chinese Medicine, Nanjing 210028, Jiangsu Province, PR China; Department of Natural Medicinal Chemistry & State Key Laboratory of Natural Medicines, China Pharmaceutical University, Nanjing 210009, Jiangsu Province, PR China
| | - YuJian Wei
- The First Clinical Medical Institute, Nanjing Medical University, Nanjing 210000, China
| | - Nan Yao
- Laboratory of Translational Medicine, Jiangsu Province Academy of Traditional Chinese Medicine, Nanjing 210028, Jiangsu Province, PR China
| | - Zhengfeng Wu
- Laboratory of Translational Medicine, Jiangsu Province Academy of Traditional Chinese Medicine, Nanjing 210028, Jiangsu Province, PR China; Department of Natural Medicinal Chemistry & State Key Laboratory of Natural Medicines, China Pharmaceutical University, Nanjing 210009, Jiangsu Province, PR China
| | - Yonglan Ma
- Laboratory of Translational Medicine, Jiangsu Province Academy of Traditional Chinese Medicine, Nanjing 210028, Jiangsu Province, PR China; Department of Natural Medicinal Chemistry & State Key Laboratory of Natural Medicines, China Pharmaceutical University, Nanjing 210009, Jiangsu Province, PR China
| | - Zi Lin
- Laboratory of Translational Medicine, Jiangsu Province Academy of Traditional Chinese Medicine, Nanjing 210028, Jiangsu Province, PR China; Department of Natural Medicinal Chemistry & State Key Laboratory of Natural Medicines, China Pharmaceutical University, Nanjing 210009, Jiangsu Province, PR China
| | - Ming Zhao
- Department of Medicinal Chemistry & Pharmacognosy, and WHO Collaboratiing Center for Tradition medicine, College of Pharmacy, University of Illinois at Chicago, Chicago, IL 60612, USA
| | - Chuntao Che
- Department of Medicinal Chemistry & Pharmacognosy, and WHO Collaboratiing Center for Tradition medicine, College of Pharmacy, University of Illinois at Chicago, Chicago, IL 60612, USA
| | - Xiaoming Yao
- Clinical Laboratory, Jiangsu Province Hospital on Integration of Chinese and Western Medicine, Nanjing 210028, Jiangsu Province, PR China
| | - Jian Zhang
- Laboratory of Translational Medicine, Jiangsu Province Academy of Traditional Chinese Medicine, Nanjing 210028, Jiangsu Province, PR China.
| | - Zhiqi Yin
- Department of Natural Medicinal Chemistry & State Key Laboratory of Natural Medicines, China Pharmaceutical University, Nanjing 210009, Jiangsu Province, PR China.
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21
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Alphonse PAS, Jones PJH. Revisiting Human Cholesterol Synthesis and Absorption: The Reciprocity Paradigm and its Key Regulators. Lipids 2015; 51:519-36. [PMID: 26620375 DOI: 10.1007/s11745-015-4096-7] [Citation(s) in RCA: 69] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2015] [Accepted: 11/09/2015] [Indexed: 12/22/2022]
Abstract
Hypercholesterolemia is a major risk factor for cardiovascular disease. Cholesterol homeostasis in the body is governed by the interplay between absorption, synthesis, and excretion or conversion of cholesterol into bile acids. A reciprocal relationship between cholesterol synthesis and absorption is known to regulate circulating cholesterol in response to dietary or therapeutic interventions. However, the degree to which these factors affect synthesis and absorption and the extent to which one vector shifts in response to the other are not thoroughly understood. Also, huge inter-individual variability exists in the manner in which the two systems act in response to any cholesterol-lowering treatment. Various factors are known to account for this variability and in light of recent experimental advances new players such as gene-gene interactions, gene-environmental effects, and gut microbiome hold immense potential in offering an explanation to the complex traits of inter-individual variability in human cholesterol metabolism. In this context, the objective of the present review is to provide an overview on cholesterol metabolism and discuss the role of potential factors such as genetics, epigenetics, epistasis, and gut microbiome, as well as other regulators in modulating cholesterol metabolism, especially emphasizing the reciprocal relationship between cholesterol synthesis and absorption. Furthermore, an evaluation of the implications of this push-pull mechanism on cholesterol-lowering strategies is presented.
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Affiliation(s)
- Peter A S Alphonse
- Human Nutritional Sciences, University of Manitoba, Winnipeg, MB, Canada. .,Richardson Centre for Functional Foods and Nutraceuticals (RCFFN), University of Manitoba, 196, Innovation Drive, SmartPark, Winnipeg, MB, R3T 2N2, Canada.
| | - Peter J H Jones
- Human Nutritional Sciences, University of Manitoba, Winnipeg, MB, Canada.,Richardson Centre for Functional Foods and Nutraceuticals (RCFFN), University of Manitoba, 196, Innovation Drive, SmartPark, Winnipeg, MB, R3T 2N2, Canada.,Food Science, University of Manitoba, Winnipeg, MB, Canada
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Sid V, Wu N, Sarna LK, Siow YL, House JD, O K. Folic acid supplementation during high-fat diet feeding restores AMPK activation via an AMP-LKB1-dependent mechanism. Am J Physiol Regul Integr Comp Physiol 2015; 309:R1215-25. [PMID: 26400185 DOI: 10.1152/ajpregu.00260.2015] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2015] [Accepted: 09/16/2015] [Indexed: 12/11/2022]
Abstract
AMPK is an endogenous energy sensor that regulates lipid and carbohydrate metabolism. Nonalcoholic fatty liver disease (NAFLD) is regarded as a hepatic manifestation of metabolic syndrome with impaired lipid and glucose metabolism and increased oxidative stress. Our recent study showed that folic acid supplementation attenuated hepatic oxidative stress and lipid accumulation in high-fat diet-fed mice. The aim of the present study was to investigate the effect of folic acid on hepatic AMPK during high-fat diet feeding and the mechanisms involved. Male C57BL/6J mice were fed a control diet (10% kcal fat), a high-fat diet (60% kcal fat), or a high-fat diet supplemented with folic acid (26 mg/kg diet) for 5 wk. Mice fed a high-fat diet exhibited hyperglycemia, hepatic cholesterol accumulation, and reduced hepatic AMPK phosphorylation. Folic acid supplementation restored AMPK phosphorylation (activation) and reduced blood glucose and hepatic cholesterol levels. Activation of AMPK by folic acid was mediated through an elevation of its allosteric activator AMP and activation of its upstream kinase, namely, liver kinase B1 (LKB1) in the liver. Consistent with in vivo findings, 5-methyltetrahydrofolate (bioactive form of folate) restored phosphorylation (activation) of both AMPK and LKB1 in palmitic acid-treated HepG2 cells. Activation of AMPK by folic acid might be responsible for AMPK-dependent phosphorylation of HMG-CoA reductase, leading to reduced hepatic cholesterol synthesis during high-fat diet feeding. These results suggest that folic acid supplementation may improve cholesterol and glucose metabolism by restoration of AMPK activation in the liver.
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Affiliation(s)
- Victoria Sid
- St. Boniface Hospital Research Centre, Winnipeg, Manitoba, Canada; Department of Physiology and Pathophysiology, Winnipeg, Manitoba, Canada
| | - Nan Wu
- St. Boniface Hospital Research Centre, Winnipeg, Manitoba, Canada; Department of Physiology and Pathophysiology, Winnipeg, Manitoba, Canada
| | - Lindsei K Sarna
- St. Boniface Hospital Research Centre, Winnipeg, Manitoba, Canada; Department of Animal Science, University of Manitoba, Winnipeg, Manitoba, Canada
| | - Yaw L Siow
- St. Boniface Hospital Research Centre, Winnipeg, Manitoba, Canada; Department of Physiology and Pathophysiology, Winnipeg, Manitoba, Canada; Agriculture and Agri-Food Canada, Winnipeg, Manitoba, Canada; and
| | - James D House
- Department of Animal Science, University of Manitoba, Winnipeg, Manitoba, Canada; Department of Human Nutritional Science, University of Manitoba, Winnipeg, Manitoba, Canada
| | - Karmin O
- St. Boniface Hospital Research Centre, Winnipeg, Manitoba, Canada; Department of Physiology and Pathophysiology, Winnipeg, Manitoba, Canada; Department of Animal Science, University of Manitoba, Winnipeg, Manitoba, Canada;
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Zhang X, Song Y, Feng M, Zhou X, Lu Y, Gao L, Yu C, Jiang X, Zhao J. Thyroid-stimulating hormone decreases HMG-CoA reductase phosphorylation via AMP-activated protein kinase in the liver. J Lipid Res 2015; 56:963-71. [PMID: 25713102 DOI: 10.1194/jlr.m047654] [Citation(s) in RCA: 65] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2014] [Indexed: 11/20/2022] Open
Abstract
Cholesterol homeostasis is strictly regulated through the modulation of HMG-CoA reductase (HMGCR), the rate-limiting enzyme of cholesterol synthesis. Phosphorylation of HMGCR inactivates it and dephosphorylation activates it. AMP-activated protein kinase (AMPK) is the major kinase phosphorylating the enzyme. Our previous study found that thyroid-stimulating hormone (TSH) increased the hepatocytic HMGCR expression, but it was still unclear whether TSH affected hepatic HMGCR phosphorylation associated with AMPK. We used bovine TSH (bTSH) to treat the primary mouse hepatocytes and HepG2 cells with or without constitutively active (CA)-AMPK plasmid or protein kinase A inhibitor (H89), and set up the TSH receptor (Tshr)-KO mouse models. The p-HMGCR, p-AMPK, and related molecular expression were tested. The ratios of p-HMGCR/HMGCR and p-AMPK/AMPK decreased in the hepatocytes in a dose-dependent manner following bTSH stimulation. The changes above were inversed when the cells were treated with CA-AMPK plasmid or H89. In Tshr-KO mice, the ratios of liver p-HMGCR/HMGCR and p-AMPK/AMPK were increased relative to the littermate wild-type mice. Consistently, the phosphorylation of acetyl-CoA carboxylase, a downstream target molecule of AMPK, increased. All results suggested that TSH could regulate the phosphorylation of HMGCR via AMPK, which established a potential mechanism for hypercholesterolemia involved in a direct action of the TSH in the liver.
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Affiliation(s)
- Xiujuan Zhang
- Departments of Endocrinology, Shandong Provincial Hospital Affiliated to Shandong University, Jinan 250021, China Institute of Endocrinology and Metabolism, Shandong Academy of Clinical Medicine, Shandong Provincial Hospital Affiliated to Shandong University, Jinan 250021, China
| | - Yongfeng Song
- Departments of Endocrinology, Shandong Provincial Hospital Affiliated to Shandong University, Jinan 250021, China Institute of Endocrinology and Metabolism, Shandong Academy of Clinical Medicine, Shandong Provincial Hospital Affiliated to Shandong University, Jinan 250021, China
| | - Mei Feng
- Scientific Center, Shandong Provincial Hospital Affiliated to Shandong University, Jinan 250021, China
| | - Xinli Zhou
- Departments of Endocrinology, Shandong Provincial Hospital Affiliated to Shandong University, Jinan 250021, China Institute of Endocrinology and Metabolism, Shandong Academy of Clinical Medicine, Shandong Provincial Hospital Affiliated to Shandong University, Jinan 250021, China
| | - Yingli Lu
- Department of Endocrinology and Metabolism, Shanghai Ninth People'sHospital Affiliated to Shanghai Jiaotong University School of Medicine, Shanghai 200011, China
| | - Ling Gao
- Institute of Endocrinology and Metabolism, Shandong Academy of Clinical Medicine, Shandong Provincial Hospital Affiliated to Shandong University, Jinan 250021, China Scientific Center, Shandong Provincial Hospital Affiliated to Shandong University, Jinan 250021, China
| | - Chunxiao Yu
- Departments of Endocrinology, Shandong Provincial Hospital Affiliated to Shandong University, Jinan 250021, China Institute of Endocrinology and Metabolism, Shandong Academy of Clinical Medicine, Shandong Provincial Hospital Affiliated to Shandong University, Jinan 250021, China
| | - Xiuyun Jiang
- Departments of Endocrinology, Shandong Provincial Hospital Affiliated to Shandong University, Jinan 250021, China Institute of Endocrinology and Metabolism, Shandong Academy of Clinical Medicine, Shandong Provincial Hospital Affiliated to Shandong University, Jinan 250021, China
| | - Jiajun Zhao
- Departments of Endocrinology, Shandong Provincial Hospital Affiliated to Shandong University, Jinan 250021, China Institute of Endocrinology and Metabolism, Shandong Academy of Clinical Medicine, Shandong Provincial Hospital Affiliated to Shandong University, Jinan 250021, China
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Gnocchi D, Pedrelli M, Hurt-Camejo E, Parini P. Lipids around the Clock: Focus on Circadian Rhythms and Lipid Metabolism. BIOLOGY 2015; 4:104-32. [PMID: 25665169 PMCID: PMC4381220 DOI: 10.3390/biology4010104] [Citation(s) in RCA: 54] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/10/2014] [Accepted: 01/28/2015] [Indexed: 12/24/2022]
Abstract
Disorders of lipid and lipoprotein metabolism and transport are responsible for the development of a large spectrum of pathologies, ranging from cardiovascular diseases, to metabolic syndrome, even to tumour development. Recently, a deeper knowledge of the molecular mechanisms that control our biological clock and circadian rhythms has been achieved. From these studies it has clearly emerged how the molecular clock tightly regulates every aspect of our lives, including our metabolism. This review analyses the organisation and functioning of the circadian clock and its relevance in the regulation of physiological processes. We also describe metabolism and transport of lipids and lipoproteins as an essential aspect for our health, and we will focus on how the circadian clock and lipid metabolism are greatly interconnected. Finally, we discuss how a deeper knowledge of this relationship might be useful to improve the recent spread of metabolic diseases.
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Affiliation(s)
- Davide Gnocchi
- Division of Clinical Chemistry, Department of Laboratory Medicine, Karolinska Institutet at Karolinska University Hospital Huddinge, Stockholm, 14186, Sweden.
| | - Matteo Pedrelli
- Division of Clinical Chemistry, Department of Laboratory Medicine, Karolinska Institutet at Karolinska University Hospital Huddinge, Stockholm, 14186, Sweden.
- Strategy and Externalization, CVMD iMED, AstraZeneca, R&D, Mölndal, SE-431 83, Sweden.
| | - Eva Hurt-Camejo
- Strategy and Externalization, CVMD iMED, AstraZeneca, R&D, Mölndal, SE-431 83, Sweden.
| | - Paolo Parini
- Division of Clinical Chemistry, Department of Laboratory Medicine, Karolinska Institutet at Karolinska University Hospital Huddinge, Stockholm, 14186, Sweden.
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Trivedi AK, Kumar J, Rani S, Kumar V. Annual life history-dependent gene expression in the hypothalamus and liver of a migratory songbird: insights into the molecular regulation of seasonal metabolism. J Biol Rhythms 2014; 29:332-45. [PMID: 25252711 DOI: 10.1177/0748730414549766] [Citation(s) in RCA: 44] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
Birds seasonally switch from one life history state (LHS) to another to maximize their fitness. Accordingly, they exhibit distinct differences in their physiological and behavioral phenotypes between seasons. Possible molecular mechanisms underlying changes through the seasons have scarcely been examined in migratory birds. The present study measured key genes suggested to be involved in the metabolic regulation of 4 photoperiodically induced seasonal LHSs in a long-distance migratory songbird, the blackheaded bunting (Emberiza melanocephala). Buntings were held under short days (8 h light:16 h darkness, 8L:16D), during which they maintained the winter nonmigratory phenotype. Then they were exposed for several weeks to long days (13L:11D). Differences in the activity-rest pattern, body fattening and weight gain, testis size, organ (heart, intestine) weights, and blood glucose and triglyceride levels confirmed that buntings sequentially exhibited spring migration-linked premigratory, migratory, and postmigratory LHSs under long days. The mRNA levels of circadian genes involved in metabolism (Bmal1, Clock, Npas2, Rorα, and Rev-erbα) and of genes that encode for proteins/enzymes involved in the regulation of glucose (Sirt1, FoxO1, Glut1, and Pygl) and lipids (Hmg-CoA; Pparα, Pparγ; Fasn and Acaca) showed LHS-dependent changes in their light-dark expression patterns in the hypothalamus and liver. These initial results on genetic regulation of metabolism in a migratory species extend the idea that the transitions between LHSs in a seasonal species are accomplished by changes at multiple regulatory levels. Thus, these findings promise new insights into the mechanism(s) of adaptation to seasons in higher vertebrates.
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Affiliation(s)
- Amit K Trivedi
- Department of Zoology, University of Delhi, Delhi, India
| | - Jayant Kumar
- Department of Zoology, University of Lucknow, Lucknow, India
| | - Sangeeta Rani
- Department of Zoology, University of Lucknow, Lucknow, India
| | - Vinod Kumar
- Department of Zoology, University of Delhi, Delhi, India
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Shi Y, Guo R, Wang X, Yuan D, Zhang S, Wang J, Yan X, Wang C. The regulation of alfalfa saponin extract on key genes involved in hepatic cholesterol metabolism in hyperlipidemic rats. PLoS One 2014; 9:e88282. [PMID: 24505463 PMCID: PMC3914959 DOI: 10.1371/journal.pone.0088282] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2013] [Accepted: 01/07/2014] [Indexed: 12/12/2022] Open
Abstract
To investigate the cholesterol-lowering effects of alfalfa saponin extract (ASE) and its regulation mechanism on some key genes involved in cholesterol metabolism, 40 healthy 7 weeks old male Sprague Dawley (SD) rats were randomly divided into four groups with 10 rats in each group: control group, hyperlipidemic group, ASE treatment group, ASE prevention group. The body weight gain, relative liver weight and serum lipid 1evels of rats were determined. Total cholesterol (TC) and total bile acids (TBA) levels in liver and feces were also measured. Furthermore, the activity and mRNA expressions of Hmgcr, Acat2, Cyp7a1 and Ldlr were investigated. The results showed the following: (1) The abnormal serum lipid levels in hyperlipidemic rats were ameliorated by ASE administration (both ASE prevention group and treatment group) (P<0.05). (2) Both ASE administration to hyperlipidemic rats significantly reduced liver TC and increased liver TBA level (P<0.05). TC and TBA levels in feces of hyperlipidemic rats were remarkably elevated by both ASE administration (P<0.05). (3) mRNA expressions of Hmgcr and Acat2 in the liver of hyperlipidemic rats were remarkably down-regulated (P<0.05), as well as mRNA expressions of Cyp7a1 and Ldlr were dramatically up-regulated by both ASE administration (P<0.05). The activities of these enzymes also paralleled the observed changes in mRNA levels. (4) There was no significant difference between ASE treatment and ASE prevention group for most parameters evaluated. Our present study indicated that ASE had cholesterol-lowering effects. The possible mechanism could be attributed to (1) the down-regulation of Hmgcr and Acat2, as well as up-regulation of Cyp7a1 and Ldlr in the liver of hyperlipidemic rats, which was involved in cholesterol biosynthesis, uptake, and efflux pathway; (2) the increase in excretion of cholesterol. The findings in our study suggested ASE had great potential usefulness as a natural agent for treating hyperlipidemia.
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Affiliation(s)
- Yinghua Shi
- College of Animal Science and Veterinary Medicine, Henan Agricultural University, Zhengzhou, Henan, China
- * E-mail: (YS); (CW)
| | - Rui Guo
- College of Animal Science and Veterinary Medicine, Henan Agricultural University, Zhengzhou, Henan, China
| | - Xianke Wang
- College of Animal Science and Veterinary Medicine, Henan Agricultural University, Zhengzhou, Henan, China
| | - Dedi Yuan
- College of Animal Science and Veterinary Medicine, Henan Agricultural University, Zhengzhou, Henan, China
| | - Senhao Zhang
- College of Animal Science and Veterinary Medicine, Henan Agricultural University, Zhengzhou, Henan, China
| | - Jie Wang
- College of Animal Science and Veterinary Medicine, Henan Agricultural University, Zhengzhou, Henan, China
| | - Xuebing Yan
- College of Animal Science and Veterinary Medicine, Henan Agricultural University, Zhengzhou, Henan, China
| | - Chengzhang Wang
- College of Animal Science and Veterinary Medicine, Henan Agricultural University, Zhengzhou, Henan, China
- * E-mail: (YS); (CW)
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Ellis MH, Baraf L, Shaish A, Har-Zahav A, Harats D, Ashur-Fabian O. Alteration of lipids and the transcription of lipid-related genes in myelodysplastic syndromes via a TP53-related pathway. Exp Hematol 2012; 40:540-547.e1. [DOI: 10.1016/j.exphem.2012.02.003] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2011] [Revised: 01/30/2012] [Accepted: 02/21/2012] [Indexed: 12/31/2022]
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Strauss V, Mellert W, Wiemer J, Leibold E, Kamp H, Walk T, Looser R, Prokoudine A, Fabian E, Krennrich G, Herold M, van Ravenzwaay B. Increased toxicity when fibrates and statins are administered in combination – A metabolomics approach with rats. Toxicol Lett 2012; 211:187-200. [DOI: 10.1016/j.toxlet.2012.03.798] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2011] [Revised: 03/19/2012] [Accepted: 03/21/2012] [Indexed: 10/28/2022]
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Zmrzljak UP, Rozman D. Circadian regulation of the hepatic endobiotic and xenobitoic detoxification pathways: the time matters. Chem Res Toxicol 2012; 25:811-24. [PMID: 22303888 DOI: 10.1021/tx200538r] [Citation(s) in RCA: 63] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
Metabolic processes have to be regulated tightly to prevent waste of energy and to ensure sufficient detoxification. Most anabolic processes operate in a timely manner when energy intake is the highest, while catabolism takes place in energy spending periods. Endobiotic and xenobiotic metabolism are therefore under circadian control. Circadian regulation is mediated through the suprachiasmatic nucleus (SCN), a master autonomous oscillator of the brain. Although many peripheral organs have their own oscillators, the SCN is important in orchestrating and entraining organs according to the environmental light cues. However, light is not the only signal for entrainment of internal clocks. For endobiotic and xenobitoic detoxification pathways, the food composition and intake regime are equally important. The rhythm of the liver as an organ where the major metabolic pathways intersect depends on SCN signals, signals from endocrine tissues, and, importantly, the type and time of feeding or xenobiotics ingestion. Several enzymes are involved in detoxification processes. Phase I is composed mainly of cytochromes P450, which are regulated by nuclear receptors. Phase II enzymes modify the phase I metabolites, while phase III includes membrane transporters responsible for the elimination of modified xenobiotics. Phases I-III of drug metabolism are under strong circadian regulation, starting with the drug-sensing nuclear receptors and ending with drug transporters. Disturbed circadian regualtion (jet-lag, shift work, and dysfunction of core clock genes) leads to changed periods of activity, sleep disorders, disturbed glucose homeostasis, breast or colon cancer, and metabolic syndrome. As many xenobiotics influence the circadian rhythm of the liver, bad drug administration timing can worsen the above listed effects. This review will cover the major hepatic circadian regulation of endogenous and xenobiotic metabolic pathways and will provide examples of how good timing of drug administration can change drug failure to treatment success.
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Affiliation(s)
- Ursula Prosenc Zmrzljak
- Faculty of Medicine, Center for Functional Genomics and Bio-Chips, Institute for Biochemistry, University of Ljubljana, Zaloska 4, SI-1000 Ljubljana, Slovenia
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Guo J, Bei W, Hu Y, Tang C, He W, Liu X, Huang L, Cao Y, Hu X, Zhong X, Cao L. A new TCM formula FTZ lowers serum cholesterol by regulating HMG-CoA reductase and CYP7A1 in hyperlipidemic rats. JOURNAL OF ETHNOPHARMACOLOGY 2011; 135:299-307. [PMID: 21396994 DOI: 10.1016/j.jep.2011.03.012] [Citation(s) in RCA: 65] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/15/2010] [Revised: 02/26/2011] [Accepted: 03/03/2011] [Indexed: 05/30/2023]
Abstract
ETHNOPHARMACOLOGICAL RELEVANCE Based on a theory of Chinese Medicine, Regulating Gan (liver) to lower lipids that is in brief to regulate the lipid metabolic related factors in the liver will improve serum lipid profile, we have developed Fufang Zhenzhu Tiao Zhi (FTZ) which includes eight herbs that are quality assured. FTZ has been developed with the potential to correct abnormal lipid metabolism. This Chinese herbal medicine has been prescribed for 20 years, which has been issued patent and clinically proven for use in the treatment of dyslipidemia. AIM OF THE STUDY To investigate the cholesterol-lowering effect and the mode of action of FTZ extract on high lipid diet induced hyperlipidemic rats. MATERIALS AND METHODS The FTZ was prepared by alcohol and water extraction of eight herbs that have been quality-controlled according to the protocol. The cholesterol-lowering effect of FTZ was evaluated on SD rats fed with high-lipid diet. RT-PCR and western blot were used to analyze the gene expression of cholesterol metabolism-related enzymes including HMG-CoA reductase and cholesterol 7α-hydroxylase (CYP7A1) in the livers of the rats. The activity of HMG-CoA reductase and CYP7A1 were assessed by colorimetrical method and by quantification of the cholesterol metabolite of CYP7A1 using HPLC analysis respectively. RESULTS AND CONCLUSIONS FTZ significantly decreased the levels of serum total cholesterol (TC), triglycerides (TG) and low-density lipoprotein cholesterol (LDL-C), whilst elevated the serum high-density lipoprotein cholesterol (HDL-C) and decreased serum atherogenic index (A.I.) values in high lipid diet induced hyperlipidemic rats. Furthermore, FTZ showed significant antihyperlipidemic effect by at least three pathways in the high lipid diet induced hyperlipidemic rats: (1) upregulating the gene expression and activity of CYP7A1 which promotes the conversion of cholesterol into bile acid; (2) downregulating the gene expression and activity of HMG-CoA reductase to reduce de novo synthesis of cholesterol; (3) increasing the cholesterol excretion from feces. In these three pathways, HMG-CoA reductase and CYP7A1 are two pivotal enzymes in lipid cholesterol metabolism and are expressed mainly in hepatic cells, which support our new TCM treatment strategy: Modulating Liver to Treat Hyperlipemia.
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Affiliation(s)
- Jiao Guo
- Institute of Chinese Medicinal Sciences, Guangdong Pharmaceutical University, Guangzhou University of Chinese Medicine, Guangzhou Higher Education Mega Centre, Guangzhou 510006, PR China.
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Wu N, Sarna LK, Siow YL, O K. Regulation of hepatic cholesterol biosynthesis by berberine during hyperhomocysteinemia. Am J Physiol Regul Integr Comp Physiol 2010; 300:R635-43. [PMID: 21178122 DOI: 10.1152/ajpregu.00441.2010] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Hyperhomocysteinemia, an elevation of blood homocysteine levels, is a metabolic disorder associated with dysfunction of multiple organs. We previously demonstrated that hyperhomocysteinemia stimulated hepatic 3-hydroxy-3-methylglutaryl coenzyme A (HMG-CoA) reductase leading to hepatic lipid accumulation and liver injury. The liver plays an important role in cholesterol biosynthesis and overall homeostasis. HMG-CoA reductase catalyzes the rate-limiting step in cholesterol biosynthesis. Hepatic HMG-CoA reductase is a major target for lowering cholesterol levels in patients with hypercholesterolemia. The aim of the present study was to examine the effect of berberine, a plant-derived alkaloid, on hepatic cholesterol biosynthesis in hyperhomocysteinemic rats and to identify the underlying mechanism. Hyperhomocysteinemia was induced in Sprague-Dawley rats by feeding a high-methionine diet for 4 wk. HMG-CoA reductase activity was markedly elevated in the liver of hyperhomocysteinemic rats, which was accompanied by hepatic lipid accumulation. Activation of HMG-CoA reductase was caused by an increase in its gene expression and a reduction in its phosphorylation (an inactive form of the enzyme). Treatment of hyperhomocysteinemic rats with berberine for 5 days inhibited HMG-CoA reductase activity and reduced hepatic cholesterol content. Such an inhibitory effect was mediated by increased phosphorylation of HMG-CoA reductase. Berberine treatment also improved liver function. These results suggest that berberine regulates hepatic cholesterol biosynthesis via increased phosphorylation of HMG-CoA reductase. Berberine may be therapeutically useful for the management of cholesterol homeostasis.
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Affiliation(s)
- Nan Wu
- St. Boniface Hospital Research Centre, Winnipeg, Canada
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Interplay between cholesterol and drug metabolism. BIOCHIMICA ET BIOPHYSICA ACTA-PROTEINS AND PROTEOMICS 2010; 1814:146-60. [PMID: 20570756 DOI: 10.1016/j.bbapap.2010.05.014] [Citation(s) in RCA: 53] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/30/2010] [Revised: 05/17/2010] [Accepted: 05/24/2010] [Indexed: 12/14/2022]
Abstract
Cholesterol biosynthetic and metabolic pathways contain several branching points towards physiologically active molecules, such as coenzyme Q, vitamin D, glucocorticoid and steroid hormones, oxysterols, or bile acids. Sophisticated regulatory mechanisms are involved in maintenance of the homeostasis of not only cholesterol but also other cholesterogenic molecules. In addition to endogenous cues, cholesterol homeostasis needs to accommodate also to exogenous cues that are imported into the body, such as chemicals and medications. Steroid and nuclear receptors together with sterol regulatory element-binding protein (SREBP) mediate the fine tuning of biosynthetic and metabolic routes as well as transports of cholesterol and its derivatives. Similarly, drug/xenobiotic metabolism is the subject to the feedback regulation of cytochrome P450 enzymes and transporters. The regulatory mechanisms that maintain the homeostasis of cholesterogenic molecules and are involved in drug metabolism share similarities. Cholesterol and cholesterogenic compounds (bile acids, glucocorticoids, vitamin D, etc.) regulate the xenosensor signaling in drug-mediated induction of the major drug-metabolizing cytochrome P450 enzymes. The key cellular receptors, pregnane X receptor (PXR), constitutive androstane receptor (CAR), vitamin D receptor (VDR), and glucocorticoid receptor (GR) provide a functional cross-talk between the pathways maintaining cholesterol homeostasis and controlling the expression of drug-metabolizing enzymes. These receptors serve as metabolic sensors, resulting in a coordinate regulation of cholesterogenic compounds metabolism and of the defense against xenobiotic and endobiotic toxicity. Herein we present a comprehensive review of functional interactions between cholesterol homeostasis and drug metabolism involving the main nuclear and steroid receptors.
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Yamajuku D, Okubo S, Haruma T, Inagaki T, Okuda Y, Kojima T, Noutomi K, Hashimoto S, Oda H. Regular Feeding Plays an Important Role in Cholesterol Homeostasis Through the Liver Circadian Clock. Circ Res 2009; 105:545-8. [DOI: 10.1161/circresaha.109.199034] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Rationale:
Peripheral clock control and the relevance of the circadian rhythm to physiology and disease are major questions in mammalian circadian biology.
Objective:
We examined the physiological functions of the liver clock.
Methods and Results:
We established a suppressed feeding schedule regimen constituting a high-cholesterol diet delivered every 6 hours without changes in energy and cholesterol intake. We found that rats exposed to this regimen developed hypercholesteremia. In the liver, the rhythmicity of expression of several clock genes was disrupted. Furthermore, the nocturnal expression of the CYP7A1 gene, which encodes the rate-limiting enzyme for the conversion of cholesterol to bile acids, was shifted to a diurnal pattern. Indeed, suppression of a regular feeding rhythm increased the secretion rate of very-low-density lipoprotein cholesterol from the liver and decreased the excretion of fecal bile acids.
Conclusions:
Our results demonstrated that not only the amount and quality of food but also the timing of meals has crucial health implications.
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Affiliation(s)
- Daisuke Yamajuku
- From the Department of Applied Molecular Biosciences (D.Y., S.O., T.H., T.I., Y.O., H.O.), Laboratory of Nutritional Biochemistry, Nagoya University; and Pharmacology Research Laboratories (D.Y.) and Molecular Medicine Research Laboratories (T.K., K.N., S.H.), Drug Discovery Research, Astellas Pharma Inc, Ibaraki, Japan
| | - Shingo Okubo
- From the Department of Applied Molecular Biosciences (D.Y., S.O., T.H., T.I., Y.O., H.O.), Laboratory of Nutritional Biochemistry, Nagoya University; and Pharmacology Research Laboratories (D.Y.) and Molecular Medicine Research Laboratories (T.K., K.N., S.H.), Drug Discovery Research, Astellas Pharma Inc, Ibaraki, Japan
| | - Tomonori Haruma
- From the Department of Applied Molecular Biosciences (D.Y., S.O., T.H., T.I., Y.O., H.O.), Laboratory of Nutritional Biochemistry, Nagoya University; and Pharmacology Research Laboratories (D.Y.) and Molecular Medicine Research Laboratories (T.K., K.N., S.H.), Drug Discovery Research, Astellas Pharma Inc, Ibaraki, Japan
| | - Takahiko Inagaki
- From the Department of Applied Molecular Biosciences (D.Y., S.O., T.H., T.I., Y.O., H.O.), Laboratory of Nutritional Biochemistry, Nagoya University; and Pharmacology Research Laboratories (D.Y.) and Molecular Medicine Research Laboratories (T.K., K.N., S.H.), Drug Discovery Research, Astellas Pharma Inc, Ibaraki, Japan
| | - Yuji Okuda
- From the Department of Applied Molecular Biosciences (D.Y., S.O., T.H., T.I., Y.O., H.O.), Laboratory of Nutritional Biochemistry, Nagoya University; and Pharmacology Research Laboratories (D.Y.) and Molecular Medicine Research Laboratories (T.K., K.N., S.H.), Drug Discovery Research, Astellas Pharma Inc, Ibaraki, Japan
| | - Tomoko Kojima
- From the Department of Applied Molecular Biosciences (D.Y., S.O., T.H., T.I., Y.O., H.O.), Laboratory of Nutritional Biochemistry, Nagoya University; and Pharmacology Research Laboratories (D.Y.) and Molecular Medicine Research Laboratories (T.K., K.N., S.H.), Drug Discovery Research, Astellas Pharma Inc, Ibaraki, Japan
| | - Keiji Noutomi
- From the Department of Applied Molecular Biosciences (D.Y., S.O., T.H., T.I., Y.O., H.O.), Laboratory of Nutritional Biochemistry, Nagoya University; and Pharmacology Research Laboratories (D.Y.) and Molecular Medicine Research Laboratories (T.K., K.N., S.H.), Drug Discovery Research, Astellas Pharma Inc, Ibaraki, Japan
| | - Seiichi Hashimoto
- From the Department of Applied Molecular Biosciences (D.Y., S.O., T.H., T.I., Y.O., H.O.), Laboratory of Nutritional Biochemistry, Nagoya University; and Pharmacology Research Laboratories (D.Y.) and Molecular Medicine Research Laboratories (T.K., K.N., S.H.), Drug Discovery Research, Astellas Pharma Inc, Ibaraki, Japan
| | - Hiroaki Oda
- From the Department of Applied Molecular Biosciences (D.Y., S.O., T.H., T.I., Y.O., H.O.), Laboratory of Nutritional Biochemistry, Nagoya University; and Pharmacology Research Laboratories (D.Y.) and Molecular Medicine Research Laboratories (T.K., K.N., S.H.), Drug Discovery Research, Astellas Pharma Inc, Ibaraki, Japan
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REV-ERBalpha participates in circadian SREBP signaling and bile acid homeostasis. PLoS Biol 2009; 7:e1000181. [PMID: 19721697 PMCID: PMC2726950 DOI: 10.1371/journal.pbio.1000181] [Citation(s) in RCA: 335] [Impact Index Per Article: 22.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2008] [Accepted: 07/16/2009] [Indexed: 12/31/2022] Open
Abstract
The nuclear receptor REV-ERBα shapes the daily activity profile of Sterol Response Element Binding Protein (SREBP) and thereby participates in the circadian control of cholesterol and bile acid synthesis in the liver. In mammals, many aspects of behavior and physiology, and in particular cellular metabolism, are coordinated by the circadian timing system. Molecular clocks are thought to rely on negative feedback loops in clock gene expression that engender oscillations in the accumulation of transcriptional regulatory proteins, such as the orphan receptor REV-ERBα. Circadian transcription factors then drive daily rhythms in the expression of clock-controlled output genes, for example genes encoding enzymes and regulators of cellular metabolism. To gain insight into clock output functions of REV-ERBα, we carried out genome-wide transcriptome profiling experiments with liver RNA from wild-type mice, Rev-erbα knock-out mice, or REV-ERBα overexpressing mice. On the basis of these genetic loss- and gain-of-function experiments, we concluded that REV-ERBα participates in the circadian modulation of sterol regulatory element-binding protein (SREBP) activity, and thereby in the daily expression of SREBP target genes involved in cholesterol and lipid metabolism. This control is exerted via the cyclic transcription of Insig2, encoding a trans-membrane protein that sequesters SREBP proteins to the endoplasmic reticulum membranes and thereby interferes with the proteolytic activation of SREBPs in Golgi membranes. REV-ERBα also participates in the cyclic expression of cholesterol-7α-hydroxylase (CYP7A1), the rate-limiting enzyme in converting cholesterol to bile acids. Our findings suggest that this control acts via the stimulation of LXR nuclear receptors by cyclically produced oxysterols. In conclusion, our study suggests that rhythmic cholesterol and bile acid metabolism is not just driven by alternating feeding–fasting cycles, but also by REV-ERBα, a component of the circadian clockwork circuitry. The mammalian circadian timing system has a hierarchical architecture: a central pacemaker in the brain's suprachiasmatic nucleus (SCN) synchronizes subsidiary oscillators present in most peripheral cell types. In both SCN neurons and peripheral cells, circadian oscillators are thought to rely on two negative feedback loops. A major feedback loop involves the two cryptochromes CRY1 and CRY2 and the two period proteins PER1 and PER2, which serve as transcriptional repressors for their own genes. An accessory feedback loop couples the expression and activity of the transcriptional activators CLOCK and BMAL1 to the expression of cryptochrome and period proteins. The orphan nuclear receptor REV-ERBα is a key player in this accessory feedback loop, in that it periodically represses Bmal1 transcription. In liver, molecular clocks mediate the temporal gating of metabolic processes. Here we demonstrate that hepatocyte clocks participate in the control of cholesterol and bile acid homeostasis. According to this scenario, REV-ERBα shapes the circadian expression pattern of insulin-induced gene 2 (INSIG2), a resident protein of the endoplasmic reticulum that interferes with the proteolytic activation of sterol response element binding proteins (SREBPs). In turn SREBPs govern the rhythmic expression of enzymes with key functions in sterol and fatty acid synthesis. The circadian production of sterols (in particular oxysterols) may engender the cyclic activation of LXR nuclear receptors, which serve as critical activators of Cyp7a1 transcription. CYP7A1, also known as cholesterol 7α-hydroxylase, catalyzes the rate-limiting step in bile acid synthesis.
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Hussain MM, Pan X. Clock genes, intestinal transport and plasma lipid homeostasis. Trends Endocrinol Metab 2009; 20:177-85. [PMID: 19349191 PMCID: PMC4544755 DOI: 10.1016/j.tem.2009.01.001] [Citation(s) in RCA: 57] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/19/2008] [Revised: 12/30/2008] [Accepted: 01/05/2009] [Indexed: 02/03/2023]
Abstract
Light and food are two major environmental factors that impact daily life. Light entrainment is centrally controlled by suprachiasmatic nuclei of the hypothalamus. Food entrainment might require cooperation between the intestine and dorsomedial hypothalamus. Clock genes that are essential for light entrainment also play a part in food entrainment. Understanding the role of clock genes in the entrainment of intestinal functions, as well as in gut-brain communication during food entrainment, will enhance our understanding of gastrointestinal and metabolic disorders. This review highlights recent studies examining light- and food-entrained regulation of plasma lipids and of various intestinal activities and offers insight into the role of the intestine in food entrainment.
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Affiliation(s)
- M Mahmood Hussain
- Department of Anatomy and Cell Biology, SUNY Downstate Medical Center, Brooklyn, NY 11203, USA.
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36
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Cibickova L, Hyspler R, Micuda S, Cibicek N, Zivna H, Jun D, Ticha A, Brcakova E, Palicka V. The influence of simvastatin, atorvastatin and high-cholesterol diet on acetylcholinesterase activity, amyloid beta and cholesterol synthesis in rat brain. Steroids 2009; 74:13-9. [PMID: 18817797 DOI: 10.1016/j.steroids.2008.08.007] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/09/2008] [Revised: 08/22/2008] [Accepted: 08/26/2008] [Indexed: 11/21/2022]
Abstract
OBJECTIVE There is evidence to suppose that cholesterol-lowering medicine might confer protection against dementia, probably via modulation of cholesterol synthesis in the brain. The aim of the present study was to investigate the potential influence of statins and cholesterol diet on selected parameters relevant to Alzheimer's disease pathophysiology. METHODS For 15 days, rats were orally administered simvastatin (10 or 20mg/kg b.wt.), atorvastatin (10 or 20mg/kg b.wt.), or aqua (control group); and one group was fed high-cholesterol (2%) diet. At the end of experiments brain (and plasma) cholesterol, lathosterol, hydroxymethylglutaryl-coenzyme A reductase protein, acetylcholinesterase activity, amyloid beta (40 and 42) and cholesterol synthesis rate (using the incorporation of deuterium from deuterated water) were determined and statistically compared to those of aqua. RESULTS Both statins were able to lower cholesterol in the plasma, but none elicited an effect on total brain cholesterol. Significant reductions of brain lathosterol and cholesterol synthesis rate were observed after simvastatin and atorvastatin treatment. Acetylcholinesterase activity, amyloid beta and hydroxymethylglutaryl-coenzyme A reductase levels remained unaffected by the two drugs. CONCLUSIONS This study brings additional evidence of a role for statins in cholesterol synthesis in the brain. Our data question the relationship between amyloid beta, acetylcholinesterase activity and cholesterol synthesis in the rat brain as well as the assumption about no exchange between peripheral and brain cholesterol pools.
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Affiliation(s)
- Lubica Cibickova
- 2nd Department of Medicine, Charles University in Prague, Medical Faculty in Hradec Kralove and University Hospital Hradec Kralove, Czech Republic.
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Acimovic J, Fink M, Pompon D, Bjorkhem I, Hirayama J, Sassone-Corsi P, Golicnik M, Rozman D. CREM modulates the circadian expression of CYP51, HMGCR and cholesterogenesis in the liver. Biochem Biophys Res Commun 2008; 376:206-10. [DOI: 10.1016/j.bbrc.2008.08.126] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2008] [Accepted: 08/27/2008] [Indexed: 01/04/2023]
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Sharma M, Rai SK, Tiwari RK, Tiwari M, Chandra R. Effects of nitric oxide modulators on cardiovascular risk factors in mild hyperhomocysteinaemic rat model. Basic Clin Pharmacol Toxicol 2008; 103:25-30. [PMID: 18598296 DOI: 10.1111/j.1742-7843.2008.00215.x] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
Hyperhomocysteinaemia is considered to be an independent risk factor in atherosclerosis. In the present article, we observed the effect of nitric oxide modulators on cardiovascular risk factors in mild hyperhomocysteinaemic rats. A rat model of mild hyperhomocysteinaemia was established by administering methionine (1 g/kg body weight, orally) for 4 weeks. The other groups were concomitantly treated with sodium nitroprusside (SNP) and N(omega)-nitro-l-arginine (LNNA) during the induction of hyperhomocysteinaemia. Lipid profile, total antioxidant capacity and the level of homocysteine and NO(x) (nitrates and nitrites) was examined in serum at 0 and 4 weeks. Activity of 3-hydroxy-3-methylglutaryl-coenzyme A (HMG-CoA) reductase, the mRNA level of caveolin, P2 receptors and cardiovascular risk factors were also analysed. Stimulated lipid profile of rats by the treatment of methionine (1 g/kg body weight) reduced significantly by the treatment of SNP with methionine. LNNA increased the level of cholesterol in aorta (P < 0.05 versus group II). SNP significantly suppressed the activity of HMG-CoA reductase. The mRNA levels of caveolin (P < 0.05), P2X (P < 0.05) and P2Y (P < 0.05) showed a significant decrease in rats administered with SNP. LNNA showed significant induction in the expression of caveolin (P < 0.01) and P2Y (P < 0.01) expression. The level of P2X showed no remarkable change in animals treated with LNNA and methionine both. These data conclude that nitric oxide modulators modulate the effect of hyperhomocysteinaemia on the other cardiovascular risk factors and confirm the finding that nitric oxide plays an important role in homocysteine-induced cardiovascular diseases.
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Affiliation(s)
- Meenakshi Sharma
- Dr. B. R. Ambedkar Center for Biomedical Research, University of Delhi, Delhi, India.
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Chmielewski M, Sucajtys-Szulc E, Kossowska E, Swierczynski J, Rutkowski B, Boguslawski W. Feedback inhibition of cholesterol biosynthesis by dietary cholesterol in experimental chronic renal failure. J Ren Nutr 2008; 18:448-55. [PMID: 18721740 DOI: 10.1053/j.jrn.2008.04.005] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2007] [Indexed: 11/11/2022] Open
Abstract
OBJECTIVE Enhanced liver cholesterol synthesis is present in experimental chronic renal failure (CRF), even though cholesterol concentrations in blood and liver are increased, suggesting that CRF results in disturbed cholesterolegenesis feedback regulation. DESIGN This study sought to elucidate whether dietary cholesterol exerts inhibitory effects on liver cholesterologenesis in CRF rats. METHODS Male Wistar rats were used. Experimental CRF was achieved by a 5/6 nephrectomy model. Cholesterologenesis was measured (1) in vivo by tritiated water incorporation into cholesterol, and (2) in vitro (using liver slices) by [(14)C]-acetate and [(3)H]-mevalonate incorporation into cholesterol. In addition, the mRNA abundance of 3-hydroxy-3-methylglutaryl-CoA reductase, a rate-limiting enzyme in cholesterologenesis pathway, as well as its activity, was determined. Finally, the mRNA level of liver sterol regulatory element-binding protein-2, a nuclear transcription factor engaged in intracellular cholesterol homeostasis, was measured. RESULTS Experimental CRF was associated with significantly increased concentrations of serum and liver cholesterol. In vitro and in vivo cholesterologenesis was enhanced in CRF rats. A cholesterol-enriched diet resulted in a significant decrease in (1) in vivo and in vitro cholesterol synthesis, (2) 3-hydroxy-3-methylglutaryl-CoA reductase gene expression, and (3) the level of liver sterol regulatory element-binding protein-2 mRNA in CRF rats. CONCLUSIONS Despite elevated plasma and liver cholesterol concentrations, cholesterologenesis is increased in CRF rats. It is, however, inhibited by dietary cholesterol. These results suggest that a feedback inhibition of cholesterologenesis by dietary cholesterol is preserved in experimental CRF.
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Affiliation(s)
- Michal Chmielewski
- Department of Nephrology, Transplantology, and Internal Medicine, Medical University of Gdansk, Gdansk, Poland.
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Noshiro M, Usui E, Kawamoto T, Kubo H, Fujimoto K, Furukawa M, Honma S, Makishima M, Honma KI, Kato Y. Multiple mechanisms regulate circadian expression of the gene for cholesterol 7alpha-hydroxylase (Cyp7a), a key enzyme in hepatic bile acid biosynthesis. J Biol Rhythms 2007; 22:299-311. [PMID: 17660447 DOI: 10.1177/0748730407302461] [Citation(s) in RCA: 68] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Cholesterol 7alpha-hydroxylase (CYP7A) and sterol 12alpha-hydroxylase (CYP8B) in bile acid biosynthesis and 3-hydroxyl-3-methylglutaryl CoA reductase (HMGCR) in cholesterol biosynthesis are the key enzymes in hepatic metabolic pathways, and their transcripts exhibit circadian expression profiles in rodent liver. The authors determined transcript levels of these enzymes and the regulatory factors for Cyp7a--including Dbp, Dec2, E4bp4, Hnf4alpha, Pparalpha, Lxralpha, Rev-erbalpha, and Rev-erbbeta--in the liver of wild-type and homozygous Clock mutant mice (Clock/Clock) and examined the effects of these transcription factors on the transcription activities of Cyp7a. The expression profile of the Cyp7a transcript in wild-type mice showed a strong circadian rhythm in both the 12L:12D light-dark cycle and constant darkness, and that in Clock/Clock also exhibited a circadian rhythm at an enhanced level with a lower amplitude, although its protein level became arrhythmic at a high level. The expression profile of Cyp8b mRNA in wild-type mice showed a shifted circadian rhythm from that of Cyp7a, becoming arrhythmic in Clock/Clock at an expression level comparable to that of wild-type mice. The expression profile of Hmgcr mRNA also lost its strong circadian rhythm in Clock/Clock , showing an expression level comparable to that of wild-type mice. The expressions of Dbp, Dec2, Rev-erbalpha, and Rev-erb beta--potent regulators for Cyp7a expression--were abolished or became arrhythmic in Clock/Clock, while other regulators for Cyp7a-Lxralpha, Hnf4alpha, Pparalpha, and E4bp4--had either less affected or enhanced expression in Clock/Clock. In luciferase reporter assays, REV-ERBalpha/beta, DBP, LXRalpha, and HNF4alpha increased the promoter activity of Cyp7a, whereas DEC2 abolished the transcription from the Cyp7a promoter: E4BP4 and PPARalpha were moderate negative regulators. Furthermore, knockdown of REV-ERBalpha/beta with siRNA suppressed Cyp7a transcript levels, and in the electrophoretic mobility shift assay, REV-ERBalpha/beta bound to the promoter of Cyp7a . These observations suggest that (1) active CLOCK is essential for the robust circadian expression of hepatic metabolic enzymes (Cyp7a, Cyp8b, and Hmgcr); (2) clock-controlled genes--DBP, DEC2, and REV-ERBalpha/beta--are direct regulators required for the robust circadian rhythm of Cyp7a; and (3) the circadian rhythm of Cyp7a is regulated by multiple transcription factors, including DBP, REV-ERBalpha/beta, LXRalpha, HNF4alpha DEC2, E4BP4, and PPARalpha.
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Affiliation(s)
- Mitsuhide Noshiro
- Department of Dental and Medical Biochemistry, Hiroshima University Graduate School of Biomedical Sciences, Hiroshima, Japan.
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Sharma M, Rai SK, Tiwari M, Chandra R. Effect of hyperhomocysteinemia on cardiovascular risk factors and initiation of atherosclerosis in Wistar rats. Eur J Pharmacol 2007; 574:49-60. [PMID: 17706635 DOI: 10.1016/j.ejphar.2007.07.022] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2007] [Revised: 06/22/2007] [Accepted: 07/04/2007] [Indexed: 10/23/2022]
Abstract
Hyperhomocysteinemia is considered an independent risk factor for atherosclerosis. The present study was designed to assess the effect of high level of serum homocysteine on other cardiovascular risk factors and markers in rats and to study its mode of action in initiating atherosclerosis. To address this issue, four different doses of methionine (0.1 g/kg, 0.25 g/kg, 0.5 g/kg, 1 g/kg) were orally administered to four groups (Group II, III, IV, V respectively) of rats (6 rats in each group) for a period of 8 weeks to get different level of homocysteine in serum. Group I was administered with saline and served as control. Our results revealed that the level of Total cholesterol, Triglyceride, and Oxidized low-density lipoproteins increased significantly with the increase in the level of serum homocysteine. The levels of Resistin, C-reactive protein and cysteinyl-leukotrienes were found to be significantly high in Group IV (P<0.001 vs Group I) and Group V (P<0.001 vs Group I) at 8 weeks. Total antioxidant capacity and nitrite/nitrate level in serum showed negative correlation with the increased dose of methionine. The mRNA expression and the enzyme activity of 3-hydroxy-3-methylglutaryl coenzyme A (HMG-CoA) reductase significantly increased only in livers of rats of Group V. Furthermore, high mRNA expression of P2 receptors and caveolin were found in aorta of rats administered with high dose of methionine (Group IV and V at 8 weeks). Data obtained from in-vitro effect of homocysteine on isolated aortic arch also showed induction in P2 receptors and caveolin with the increase in the concentration of homocysteine. These findings collectively suggest that hyperhomocysteinemia initiates atherosclerosis by modulating the cholesterol biosynthesis and by significantly inducing the level of other cardiovascular risk factors and markers, which play important role in initiating atherosclerosis.
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Affiliation(s)
- Meenakshi Sharma
- Dr. B. R. Ambedkar Center for Biomedical Research, University of Delhi, Delhi, India
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42
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Pan X, Hussain MM. Diurnal regulation of microsomal triglyceride transfer protein and plasma lipid levels. J Biol Chem 2007; 282:24707-19. [PMID: 17575276 DOI: 10.1074/jbc.m701305200] [Citation(s) in RCA: 111] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Plasma lipids are maintained within a narrow physiologic range and exhibit circadian rhythmicity. Plasma triglyceride and cholesterol levels were high in the night due to changes in apolipoprotein B-lipoproteins in ad libitum fed rats and mice maintained in a 12-h photoperiod. Absorption of [(3)H]triolein or [(3)H]cholesterol was higher at 2400 h than at 1200 h, indicating that intestinal lipoprotein production shows diurnal variation. Moreover, intestinal microsomal triglyceride transfer protein (MTP) activity, protein, mRNA, and gene transcription showed diurnal variations and were high at 2400 h. Similar to the small intestine, hepatic MTP activity, protein, and mRNA levels also changed significantly within a day. MTP was induced in fasted animals soon after refeeding. When mice were subjected to restricted feeding, MTP expression was high at the expected time of food availability. In contrast, extended exposures to light and dark completely abolished rhythmicity in MTP expression and plasma lipid levels. These studies show that MTP expression and plasma lipid undergo diurnal regulation and exhibit peaks and nadirs at similar times and suggest that diurnal modulation of MTP is a major determinant of daily changes in plasma lipids. Furthermore, environmental factors, such as food and light, play an important role in MTP regulation.
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Affiliation(s)
- Xiaoyue Pan
- Department of Anatomy and Cell Biology, State University of New York Downstate Medical Center, Brooklyn, New York 11203, USA
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Alejandre MJ, Perales S, Carazo A, Palomino-Morales R, Linares A. Cyclic fluctuations of 3-hydroxy-3-methylglutaryl-CoA reductase in aortic smooth muscle cell cultures. Lipids 2007; 41:1089-99. [PMID: 17269554 DOI: 10.1007/s11745-006-5058-x] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
The cyclic fluctuations of HMG-CoA reductase activity and mRNA are reportedly related to feeding the cells in culture or to variations in food consumption by the animals over a 24-h cycle. In this work, we demonstrate cyclic increments in HMG-CoA reductase activity in smooth muscle cells (SMC) not associated with the culture feeding. Since reductase activity also shows a marked rise preceding the S phase, one of the major goals of the present work was to evaluate this dual role of reductase activity and mRNA fluctuations related to the cell cycle and to food intake in the SMC-C/SMC-Ch cultures derived from control-fed (SMC-C) and cholesterol-fed (SMC-Ch) chicks. The period and amplitude oscillations in HMG-CoA reductase activity varied depending on culture conditions: lipoprotein-deficient serum vs. FBS, young vs. senescent cells, or confluent vs. nonconfluent cultures. The HMG-CoA reductase mRNA concentration showed a marked rise after feeding not correlated to the fluctuation activity, suggesting posttranscriptional modulation. Reductase activity and mRNA were down-regulated in SMC-Ch. Since the nutritional culture conditions were the same in both cell lines, these findings indicate that consumption of a high-cholesterol diet by the animals prior to the establishment of the SMC cultures induced changes in the HMG-CoA reductase gene expression in-aortic SMC.
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Affiliation(s)
- Maria José Alejandre
- Department of Biochemistry and Molecular Biology, Faculty of Sciences, University of Granada, 18071 Granada, Spain
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Ishida N. Circadian clock, cancer and lipid metabolism. Neurosci Res 2007; 57:483-90. [PMID: 17303272 DOI: 10.1016/j.neures.2006.12.012] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2006] [Revised: 12/22/2006] [Accepted: 12/25/2006] [Indexed: 10/23/2022]
Abstract
Genetic analysis has revealed that mammalian circadian oscillator is driven by a cell autonomous transcription/translation-based negative feedback loop, wherein positive elements (CLOCK and BMAL1) induce the expression of negative regulators (Periods, CRY1 and CRY2) that inhibit the transactivation of positive regulators. Recent research reveals that this clock feedback loop affects many aspects of our physiology, such as cell cycle and lipid metabolism. In this review, I summarize the molecular links between the circadian clock mechanism and the cell cycle, and between the clock and lipid metabolism. Recent studies of clock mutants also suggest that clock molecules play a role as stress sensors. Lastly, we propose the importance of sterol for entraining peripheral clocks.
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Affiliation(s)
- Norio Ishida
- Clock Cell Biology, Department of Biological Resources and Functions, National Institute of Advanced Industrial Science and Technology (AIST), 6-5 Tsukuba Center, 1-1 Higashi, Tsukuba 305-8566, Japan.
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Hoyer S, Riederer P. Alzheimer disease--no target for statin treatment. A mini review. Neurochem Res 2006; 32:695-706. [PMID: 17063393 DOI: 10.1007/s11064-006-9168-x] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2006] [Accepted: 09/11/2006] [Indexed: 10/24/2022]
Abstract
Nosologically, Alzheimer disease (AD) is not a single disorder. A minority of around 400 families worldwide can be grouped as hereditary in origin, whereas the majority of all Alzheimer cases (approx. 25 million worldwide) are sporadic in origin. In the pathophysiology of the latter type, a number of susceptibility genes contribute to the disease among which are allelic abnormalities of the apolipoprotein E4 gene pointing to a link between disturbed cholesterol metabolism and sporadic AD. Cholesterol is a main component of membrane composition enriched in microdomains and is functionally linked to the proteolytic processing of amyloid precursor protein (APP). In sporadic AD, a marked diminution of both membrane phospholipids and cholesterol has been found. Evidence has been provided that high plasma cholesterol may protect from AD. In contrast to these well documented abnormalities observed in AD patients, it was assumed that an elevated cholesterol concentration might favour the generation of beta-amyloid and, thus, AD. However, a series of in vitro-and in vivo-studies did not provide evidence for the assumption that an enhanced cholesterol concentration increased betaA4-production. A harsh reduction of membrane cholesterol only caused a "beneficial" effect of APP metabolism. However, this experimentally induced condition may not be compatible to sporadic AD. The application of statins in sporadic AD did not yield results to assume that this therapeutic strategy may prevent or treat successfully sporadic AD.
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Affiliation(s)
- Siegfried Hoyer
- Department of Pathology, University of Heidelberg, Im Neuenheimer Feld 220/221, D-69120 Heidelberg, Germany.
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Santosa S, Varady KA, AbuMweis S, Jones PJH. Physiological and therapeutic factors affecting cholesterol metabolism: does a reciprocal relationship between cholesterol absorption and synthesis really exist? Life Sci 2006; 80:505-14. [PMID: 17113605 DOI: 10.1016/j.lfs.2006.10.006] [Citation(s) in RCA: 74] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2006] [Revised: 09/18/2006] [Accepted: 10/10/2006] [Indexed: 01/06/2023]
Abstract
Cholesterol absorption and synthesis contribute to maintaining cholesterol homeostasis. Several physiological and therapeutic factors affect cholesterol homeostasis, including: genetics, circadian rhythm, body weight, plant sterols, ezetimibe, and statin therapy. The present objective is to determine the main vector, i.e. cholesterol absorption or synthesis, affected by each of these factors, and to examine whether an alteration in one vector is linked to a reciprocal change in the other. Current techniques used to assess cholesterol absorption and synthesis are also reviewed. Review of physiological factors affecting cholesterol metabolism suggest a reciprocal relationship between these two vectors. Carriers of the E2 isoform of apolipoprotein E and ATP binding cassette (ABC) G8 19H (exon 1 mutation) show a decrease in cholesterol absorption accompanied by a corresponding increase in synthesis. Circadian rhythm affects cholesterol synthesis, however, its effect on absorption has yet to be established. Obese subjects show an increase in cholesterol synthesis with a subsequent decrease in cholesterol absorption. Weight loss down regulates cholesterol synthesis, but has little or no effect on absorption. In the case of therapeutic factors, plant sterols and stanols inhibit cholesterol absorption, which results in a compensatory increase in synthesis. Ezetimibe also decreases intestinal absorption, while reciprocally increasing synthesis. Statin therapy down regulates synthesis, which is accompanied by a rise in absorption. These findings suggest that a change in one vector, fairly consistently, results in a compensatory and opposing change in the other. An understanding of this reciprocal relationship between cholesterol absorption and synthesis may allow for the development of more effective interventions for dyslipidemic disorders.
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Affiliation(s)
- Sylvia Santosa
- School of Dietetics and Human Nutrition, McGill University, Montreal, Quebec, Canada
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47
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Michikawa M. Role of cholesterol in amyloid cascade: cholesterol-dependent modulation of tau phosphorylation and mitochondrial function. Acta Neurol Scand 2006; 185:21-6. [PMID: 16866907 DOI: 10.1111/j.1600-0404.2006.00681.x] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Apolipoprotein E (apoE) alleles are important genetic risk factors for Alzheimer's disease (AD), with the epsilon4 allele increasing and the epsilon2 allele decreasing the risk of developing AD. ApoE is the major apolipoprotein that modulates cholesterol transport in the central nervous system, cholesterol being an essential component of membranes for maintaining their structure and functions. Epidemiological studies have suggested a link between serum cholesterol levels and AD development and the potential therapeutic effectiveness of statins for AD; and furthermore, biological studies have shown that amyloid beta-protein (Abeta) secretion is modulated by cellular cholesterol level. However, other lines of evidence show controversial results. In addition to the role of cholesterol in Abeta generation, different interactions of cholesterol with Abeta and its role in AD pathogenesis have been shown, i.e. Abeta affects cholesterol dynamics in neurons, and altered cholesterol metabolism in turn leads to neurodegeneration with abnormally phosphorylated tau (tauopathy). In this review, the reciprocal interactions between cholesterol and Abeta, and the role of cholesterol in tauopathy are discussed. The isoform-specific involvement of apoE in this cascade, in which high-density lipoprotein-like particles are generated and supplied to neurons to maintain cholesterol homeostasis, is also discussed.
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Affiliation(s)
- M Michikawa
- Department of Alzheimer's Disease Research, National Institute for Longevity Sciences, National Institute for Geriatrics and Gerontology, Aichi, Japan.
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AbuMweis SS, Vanstone CA, Ebine N, Kassis A, Ausman LM, Jones PJH, Lichtenstein AH. Intake of a single morning dose of standard and novel plant sterol preparations for 4 weeks does not dramatically affect plasma lipid concentrations in humans. J Nutr 2006; 136:1012-6. [PMID: 16549466 DOI: 10.1093/jn/136.4.1012] [Citation(s) in RCA: 43] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Recommendations for decreasing the risk of developing cardiovascular disease include increasing the intake of plant sterols and fish oil. The cholesterol-lowering action of plant sterols, when provided in a fish-oil fatty acids vehicle, remains to be investigated in humans. A randomized, crossover-feeding, single-blind trial was conducted in 30 subjects with mild-to-moderate hypercholesterolemia to study the effects on plasma lipids of 2 novel forms of plant sterols: those combined with, or esterified to, fish-oil fatty acids. The treatments were margarine (control), free plant sterols, plant sterols esterified to fatty acids from sunflower oil, plant sterols esterified to very long-chained fatty acids from fish oil, and plant sterols combined with the same amount of very long-chained fatty acids from fish oil. Each sterol-containing food (1.0-1.8 g plant sterols/d) was consumed for 29 d as a single dose with breakfast under staff supervision. Compared with the control treatment, none of the plant sterol preparations reduced plasma total cholesterol or LDL cholesterol, triacylglycerol, apolipoprotein A-I, apolipoprotein B, lipoprotein (a), or C-reactive protein concentration. Relative to the control phase, all plant sterols treatment increased the plasma HDL cholesterol concentration (P < 0.05) by approximately 8%. In conclusion, because standard forms of plant sterols did not reduce plasma cholesterol concentrations, the efficacy of the new formulation of plant sterols cannot be confirmed from the present study design, where plant sterols were given as a single morning dose.
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Affiliation(s)
- Suhad S AbuMweis
- School of Dietetics and Human Nutrition, McGill University, Montréal, Quebec, Canada
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49
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Cirelli C, Gutierrez CM, Tononi G. Extensive and divergent effects of sleep and wakefulness on brain gene expression. Neuron 2005; 41:35-43. [PMID: 14715133 DOI: 10.1016/s0896-6273(03)00814-6] [Citation(s) in RCA: 433] [Impact Index Per Article: 22.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
Abstract
Sleep is present in all species where it has been studied, but its functions remain unknown. To investigate what benefits sleep may bring at the cellular level, we profiled gene expression in awake and sleeping rats by using high-density microarrays. We find that approximately 10% of the transcripts in the cerebral cortex change their expression between day and night and demonstrate that half of them are modulated by sleep and wakefulness independent of time of day. We also show that molecular correlates of sleep are found in the cerebellum, a structure not known for generating sleep rhythms. Finally, we show that different functional categories of genes are selectively associated with sleep and wakefulness. The approximately 100 known genes whose expression increases during sleep provide molecular support for the proposed involvement of sleep in protein synthesis and neural plasticity and point to a novel role for sleep in membrane trafficking and maintenance.
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Affiliation(s)
- Chiara Cirelli
- Department of Psychiatry, University of Wisconsin, Madison, 53719, USA.
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50
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Woo CWH, Siow YL, Pierce GN, Choy PC, Minuk GY, Mymin D, O K. Hyperhomocysteinemia induces hepatic cholesterol biosynthesis and lipid accumulation via activation of transcription factors. Am J Physiol Endocrinol Metab 2005; 288:E1002-10. [PMID: 15644462 DOI: 10.1152/ajpendo.00518.2004] [Citation(s) in RCA: 80] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Hyperhomocysteinemia is an independent risk factor for cardiovascular disorders. Elevated plasma homocysteine (Hcy) concentration is associated with other cardiovascular risk factors. We previously reported that Hcy stimulated cholesterol biosynthesis in HepG2 cells. In the present study, we investigated the underlying mechanisms of Hcy-induced hepatic cholesterol biosynthesis in an animal model. Hyperhomocysteinemia was induced in Sprague-Dawley rats by feeding a high-methionine diet for 4 wk. The mRNA expression and the enzyme activity of 3-hydroxy-3-methylglutaryl coenzyme A (HMG-CoA) reductase were significantly increased in livers of hyperhomocysteinemic rats. There were marked hepatic lipid accumulation and an elevation of plasma cholesterol concentration in hyperhomocysteinemic rats. Three transcription factors, namely, sterol regulatory element-binding protein-2 (SREBP-2), cAMP response element-binding protein (CREB), and nuclear factor Y (NF-Y) were activated in livers of hyperhomocysteinemic rats. Upon Hcy treatment of hepatocytes, there was a significant increase in HMG-CoA reductase mRNA expression in these cells. The activation of SREBP-2, CREB, and NF-Y preceded the increase in HMG-CoA reductase expression in Hcy-treated cells. Pretreatment of hepatocytes with inhibitors for transcription factors not only blocked the activation of SREBP-2, CREB, and NF-Y but also attenuated Hcy-induced HMG-CoA reductase mRNA expression. These results suggested that hyperhomocysteinemia-induced activation of SREBP-2, CREB, and NF-Y was responsible for increased cholesterol biosynthesis by transcriptionally regulating HMG-CoA reductase expression in the liver leading to hepatic lipid accumulation and subsequently hypercholesterolemia. In conclusion, the stimulatory effect of Hcy on hepatic cholesterol biosynthesis may represent an important mechanism for hepatic lipid accumulation and cardiovascular disorder associated with hyperhomocysteinemia.
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Affiliation(s)
- Connie W H Woo
- Department of Physiology, St. Boniface Hospital Research Centre, Faculty of Medicine, R4032, 351 Tache Ave., Winnipeg, Manitoba, Canada R2H 2A6
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