101
|
Short-chain fatty acids and inulin, but not guar gum, prevent diet-induced obesity and insulin resistance through differential mechanisms in mice. Sci Rep 2017; 7:6109. [PMID: 28733671 PMCID: PMC5522422 DOI: 10.1038/s41598-017-06447-x] [Citation(s) in RCA: 145] [Impact Index Per Article: 20.7] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2017] [Accepted: 06/13/2017] [Indexed: 01/07/2023] Open
Abstract
The role of dietary fibre and short-chain fatty acids (SCFA) in obesity development is controversially discussed. Here, we investigated how various types of dietary fibre and different SCFA ratios affect metabolic syndrome-related disorders. Male mice (B6) were fed high-fat diets supplemented with dietary fibres (either cellulose, inulin or guar gum) or different Ac:Pr ratios (high acetate (HAc) or propionate (HPr)) for 30 weeks. Body-fat gain and insulin resistance were greatly reduced by inulin, but not by guar gum, and completely prevented by SCFA supplementation. Only inulin and HAc increased body temperature, possibly by the induction of beige/browning markers in WAT. In addition, inulin and SCFA lowered hepatic triglycerides and improved insulin sensitivity. Both, inulin and HAc reduced hepatic fatty acid uptake, while only inulin enhanced mitochondrial capacity and only HAc suppressed lipogenesis in liver. Interestingly, HPr was accompanied by the induction of Nrg4 in BAT. Fermentable fibre supplementation increased the abundance of bifidobacteria; B. animalis was particularly stimulated by inulin and B. pseudolongum by guar gum. We conclude that in contrast to guar gum, inulin and SCFA prevent the onset of diet-induced weight gain and hepatic steatosis by different mechanisms on liver and adipose tissue metabolism.
Collapse
|
102
|
Leitch AC, Probert PME, Shayman JA, Meyer SK, Kass GEN, Wright MC. B-13 progenitor-derived hepatocytes (B-13/H cells) model lipid dysregulation in response to drugs and chemicals. Toxicology 2017; 386:120-132. [PMID: 28552552 PMCID: PMC5553091 DOI: 10.1016/j.tox.2017.05.014] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2017] [Revised: 05/19/2017] [Accepted: 05/23/2017] [Indexed: 01/27/2023]
Abstract
Lipid dysregulation is a common hepatic adverse outcome after exposure to toxic drugs and chemicals. A donor-free rat hepatocyte-like (B-13/H) cell was therefore examined as an in vitro model for investigating mechanisms. The B-13/H cell irreversibly accumulated triglycerides (steatosis) in a time- and dose-dependent manner when exposed to fatty acids, an effect that was potentiated by the combined addition of hyperglycaemic levels of glucose and insulin. B-13/H cells also expressed the LXR nuclear receptors and exposure to their activators – T0901317 or GW3965 – induced luciferase expression from a transfected LXR-regulated reporter gene construct and steatosis in a dose-dependent manner with T0901317. Exposing B-13/H cells to a variety of cationic amphiphilic drugs – but not other hepatotoxins – also resulted in a time- and dose-dependent accumulation of phospholipids (phospholipidosis), an effect that was reduced by over-expression of lysosomal phospholipase A2. Through application of this model, hepatotoxin methapyrilene exposure was shown to induce phospholipidosis in both B-13 and B-13/H cells in a time- and dose-dependent manner. However, methapyrilene was only toxic to B-13/H cells and inhibitors of hepatotoxicity enhanced phospholipidosis, suggesting phospholipidosis is not a pathway in toxicity for this withdrawn drug. In contrast, pre-existing steatosis had minimal effect on methapyrilene hepatotoxicity in B-13/H cells. These data demonstrate that the donor free B-13 cell system for generating hepatocyte-like cells may be employed in studies of fatty acid- and LXR activator-induced steatosis and phospholipidosis and in the dissection of pathways leading to adverse outcomes such as hepatotoxicity.
Collapse
Affiliation(s)
- Alistair C Leitch
- Institute of Cellular Medicine, Medical School, Newcastle University, Newcastle Upon Tyne, UK
| | - Philip M E Probert
- Institute of Cellular Medicine, Medical School, Newcastle University, Newcastle Upon Tyne, UK
| | - James A Shayman
- Department of Internal Medicine, University of Michigan Medical School, University of Michigan, Ann Arbor, MI, USA
| | - Stephanie K Meyer
- Institute of Cellular Medicine, Medical School, Newcastle University, Newcastle Upon Tyne, UK
| | - George E N Kass
- Institute of Cellular Medicine, Medical School, Newcastle University, Newcastle Upon Tyne, UK; European Food Safety Authority, Parma, Italy
| | - Matthew C Wright
- Institute of Cellular Medicine, Medical School, Newcastle University, Newcastle Upon Tyne, UK.
| |
Collapse
|
103
|
Zhang X, Heckmann BL, Campbell LE, Liu J. G0S2: A small giant controller of lipolysis and adipose-liver fatty acid flux. Biochim Biophys Acta Mol Cell Biol Lipids 2017. [PMID: 28645852 DOI: 10.1016/j.bbalip.2017.06.007] [Citation(s) in RCA: 57] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
The discovery of adipose triglyceride lipase (ATGL) and its coactivator comparative gene identification-58 (CGI-58) provided a major paradigm shift in the understanding of intracellular lipolysis in both adipocytes and nonadipocyte cells. The subsequent discovery of G0/G1 switch gene 2 (G0S2) as a potent endogenous inhibitor of ATGL revealed a unique mechanism governing lipolysis and fatty acid (FA) availability. G0S2 is highly conserved in vertebrates, and exhibits cyclical expression pattern between adipose tissue and liver that is critical to lipid flux and energy homeostasis in these two tissues. Biochemical and cell biological studies have demonstrated that a direct interaction with ATGL mediates G0S2's inhibitory effects on lipolysis and lipid droplet degradation. In this review we examine evidence obtained from recent in vitro and in vivo studies that lends support to the proof-of-principle concept that G0S2 functions as a master regulator of tissue-specific balance of TG storage vs. mobilization, partitioning of metabolic fuels between adipose and liver, and the whole-body adaptive energy response. This article is part of a Special Issue entitled: Recent Advances in Lipid Droplet Biology edited by Rosalind Coleman and Matthijs Hesselink.
Collapse
Affiliation(s)
- Xiaodong Zhang
- Department of Biochemistry & Molecular Biology, Mayo Clinic College of Medicine, Scottsdale, AZ, United States; HEAL(th) Program, Mayo Clinic, Scottsdale, AZ, United States
| | - Bradlee L Heckmann
- Department of Immunology, St. Jude Children's Research Hospital, Memphis, TN, United States
| | - Latoya E Campbell
- School of Life Sciences, Arizona State University, Tempe, AZ, United States
| | - Jun Liu
- Department of Biochemistry & Molecular Biology, Mayo Clinic College of Medicine, Scottsdale, AZ, United States; HEAL(th) Program, Mayo Clinic, Scottsdale, AZ, United States; Division of Endocrinology, Mayo Clinic, Scottsdale, AZ, United States.
| |
Collapse
|
104
|
Li S, Monroig Ó, Wang T, Yuan Y, Carlos Navarro J, Hontoria F, Liao K, Tocher DR, Mai K, Xu W, Ai Q. Functional characterization and differential nutritional regulation of putative Elovl5 and Elovl4 elongases in large yellow croaker (Larimichthys crocea). Sci Rep 2017; 7:2303. [PMID: 28536436 PMCID: PMC5442133 DOI: 10.1038/s41598-017-02646-8] [Citation(s) in RCA: 50] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2017] [Accepted: 04/13/2017] [Indexed: 01/19/2023] Open
Abstract
In the present study, two elongases, Elovl4 and Elovl5, were functionally characterized and their transcriptional regulation in response to n-3 LC-PUFA administration were investigated in vivo and in vitro. We previously described the molecular characterization of croaker elovl5. Here, we report the full-length cDNA sequence of croaker elovl4, which contained 1794 bp (excluding the polyA tail), including 909 bp of coding region that encoded a polypeptide of 302 amino acids possessing all the characteristic features of Elovl proteins. Functional studies showed that croaker Elovl5, displayed high elongation activity towards C18 and C20 PUFA, with only low activity towards C22 PUFA. In contrast, croaker Elovl4 could effectively convert both C20 and C22 PUFA to longer polyenoic products up to C34. n-3 LC-PUFA suppressed transcription of the two elongase genes, as well as srebp-1 and lxrα, major regulators of hepatic lipid metabolism. The results of dual-luciferase reporter assays and in vitro studies both indicated that the transcriptions of elovl5 and elovl4 elongases could be regulated by Lxrα. Moreover, Lxrα could mediate the transcription of elovl4 directly or indirectly through regulating the transcription of srebp-1. The above findings contribute further insight and understanding of the mechanisms regulating LC-PUFA biosynthesis in marine fish species.
Collapse
Affiliation(s)
- Songlin Li
- Key Laboratory of Aquaculture Nutrition and Feed (Ministry of Agriculture) and Key Laboratory of Mariculture (Ministry of Education), Ocean University of China, Qingdao, 266003, People's Republic of China
| | - Óscar Monroig
- Institute of Aquaculture, School of Natural Sciences, University of Stirling, Stirling, FK9 4LA, Scotland, UK
| | - Tianjiao Wang
- Key Laboratory of Aquaculture Nutrition and Feed (Ministry of Agriculture) and Key Laboratory of Mariculture (Ministry of Education), Ocean University of China, Qingdao, 266003, People's Republic of China
| | - Yuhui Yuan
- Key Laboratory of Aquaculture Nutrition and Feed (Ministry of Agriculture) and Key Laboratory of Mariculture (Ministry of Education), Ocean University of China, Qingdao, 266003, People's Republic of China
| | - Juan Carlos Navarro
- Instituto de Acuicultura Torre de la Sal (IATS-CSIC), Ribera de Cabanes, 12595, Castellón, Spain
| | - Francisco Hontoria
- Instituto de Acuicultura Torre de la Sal (IATS-CSIC), Ribera de Cabanes, 12595, Castellón, Spain
| | - Kai Liao
- Key Laboratory of Aquaculture Nutrition and Feed (Ministry of Agriculture) and Key Laboratory of Mariculture (Ministry of Education), Ocean University of China, Qingdao, 266003, People's Republic of China
| | - Douglas R Tocher
- Institute of Aquaculture, School of Natural Sciences, University of Stirling, Stirling, FK9 4LA, Scotland, UK
| | - Kangsen Mai
- Key Laboratory of Aquaculture Nutrition and Feed (Ministry of Agriculture) and Key Laboratory of Mariculture (Ministry of Education), Ocean University of China, Qingdao, 266003, People's Republic of China
| | - Wei Xu
- Key Laboratory of Aquaculture Nutrition and Feed (Ministry of Agriculture) and Key Laboratory of Mariculture (Ministry of Education), Ocean University of China, Qingdao, 266003, People's Republic of China
| | - Qinghui Ai
- Key Laboratory of Aquaculture Nutrition and Feed (Ministry of Agriculture) and Key Laboratory of Mariculture (Ministry of Education), Ocean University of China, Qingdao, 266003, People's Republic of China. .,Laboratory for Marine Fisheries and Aquaculture, Qingdao National Laboratory for Marine Science and Technology, Qingdao, 266003, People's Republic of China.
| |
Collapse
|
105
|
Dong Y, Xu Z, Zhang Z, Yin X, Lin X, Li H, Zheng F. Impaired adipose expansion caused by liver X receptor activation is associated with insulin resistance in mice fed a high-fat diet. J Mol Endocrinol 2017; 58:141-154. [PMID: 28258092 DOI: 10.1530/jme-16-0196] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/26/2017] [Accepted: 01/30/2017] [Indexed: 12/23/2022]
Abstract
Liver X receptors (LXR) are deemed as potential drug targets for atherosclerosis, whereas a role in adipose tissue expansion and its relation to insulin sensitivity remains unclear. To assess the metabolic effects of LXR activation by the dual LXRα/β agonist T0901317, C57BL/6 mice fed a high-fat diet (HFD) were treated with T0901317 (30 mg/kg once daily by intraperitoneal injection) for 3 weeks. Differentiated 3T3-L1 adipocytes were used for analysing the effect of T0901317 on glucose uptake. The following results were obtained from this study. T0901317 reduced fat mass, accompanied by a massive fatty liver and lower serum adipokine levels in HFD mice. Increased adipocyte apoptosis was found in epididymal fat of T0901317-treated HFD mice. In addition, T0901317 treatment promoted basal lipolysis, but blunted the anti-lipolytic action of insulin. Furthermore, LXR activation antagonised PPARγ target genes in epididymal fat and PPARγ-PPRE-binding activity in 3T3-L1 adipocytes. Although the glucose tolerance was comparable to that in HFD mice, the insulin response during IPGTT was significantly higher and the insulin tolerance was significantly impaired in T0901317-treated HFD mice, indicating decreased insulin sensitivity by T0901317 administration, and which was further supported by impaired insulin signalling found in epididymal fat and decreased insulin-induced glucose uptake in 3T3-L1 adipocytes by T0901317 administration. In conclusion, these findings reveal that LXR activation impairs adipose expansion by increasing adipocyte apoptosis, lipolysis and antagonising PPARγ-mediated transcriptional activity, which contributes to decreased insulin sensitivity in whole body. The potential of LXR activation being a therapeutic target for atherosclerosis might be limited by the possibility of exacerbating insulin resistance.
Collapse
Affiliation(s)
- Yueting Dong
- Department of EndocrinologySir Run Run Shaw Hospital Affiliated with School of Zhejiang University, Hangzhou, Zhejiang, People's Republic of China
| | - Zhiye Xu
- Department of EndocrinologySir Run Run Shaw Hospital Affiliated with School of Zhejiang University, Hangzhou, Zhejiang, People's Republic of China
| | - Ziyi Zhang
- Department of EndocrinologySir Run Run Shaw Hospital Affiliated with School of Zhejiang University, Hangzhou, Zhejiang, People's Republic of China
| | - Xueyao Yin
- Department of EndocrinologySir Run Run Shaw Hospital Affiliated with School of Zhejiang University, Hangzhou, Zhejiang, People's Republic of China
| | - Xihua Lin
- Biomedical Research Center and Key Laboratory of Biotherapy of Zhejiang ProvinceSir Run Run Shaw Hospital Affiliated with School of Zhejiang University, Hangzhou, Zhejiang, People's Republic of China
| | - Hong Li
- Department of EndocrinologySir Run Run Shaw Hospital Affiliated with School of Zhejiang University, Hangzhou, Zhejiang, People's Republic of China
| | - Fenping Zheng
- Department of EndocrinologySir Run Run Shaw Hospital Affiliated with School of Zhejiang University, Hangzhou, Zhejiang, People's Republic of China
| |
Collapse
|
106
|
Regulation of hepatic lipogenesis by the zinc finger protein Zbtb20. Nat Commun 2017; 8:14824. [PMID: 28327662 PMCID: PMC5364431 DOI: 10.1038/ncomms14824] [Citation(s) in RCA: 40] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2016] [Accepted: 02/03/2017] [Indexed: 12/13/2022] Open
Abstract
Hepatic de novo lipogenesis (DNL) converts carbohydrates into triglycerides and is known to influence systemic lipid homoeostasis. Here, we demonstrate that the zinc finger protein Zbtb20 is required for DNL. Mice lacking Zbtb20 in the liver exhibit hypolipidemia and reduced levels of liver triglycerides, along with impaired hepatic lipogenesis. The expression of genes involved in glycolysis and DNL, including that of two ChREBP isoforms, is decreased in livers of knockout mice. Zbtb20 binds to and enhances the activity of the ChREBP-α promoter, suggesting that altered metabolic gene expression is mainly driven by ChREBP. In addition, ChREBP-β overexpression largely restores hepatic expression of genes involved in glucose and lipid metabolism, and increases plasma and liver triglyceride levels in knockout mice. Finally, we show that Zbtb20 ablation protects from diet-induced liver steatosis and improves hepatic insulin resistance. We suggest ZBTB20 is an essential regulator of hepatic lipogenesis and may be a therapeutic target for the treatment of fatty liver disease. De novo lipogenesis is tightly controlled by hormonal and nutritional signals and plays an important role in energy homoeostasis. Here, Liu et al. show that zinc finger protein ZBTB20 regulates the expression of key glycolytic and lipogenic genes by modulating ChREBP expression and transcriptional activity.
Collapse
|
107
|
Heckmann BL, Zhang X, Saarinen AM, Schoiswohl G, Kershaw EE, Zechner R, Liu J. Liver X receptor α mediates hepatic triglyceride accumulation through upregulation of G0/G1 Switch Gene 2 expression. JCI Insight 2017; 2:e88735. [PMID: 28239648 DOI: 10.1172/jci.insight.88735] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Abstract
Liver X receptors (LXRs) are transcription factors essential for cholesterol homeostasis and lipogenesis. LXRα has been implicated in regulating hepatic triglyceride (TG) accumulation upon both influx of adipose-derived fatty acids (FAs) during fasting and stimulation of de novo FA synthesis by chemical agonism of LXR. However, whether or not a convergent mechanism is employed to drive deposition of FAs from these 2 different sources in TGs is undetermined. Here, we report that the G0/G1 Switch Gene 2 (G0S2), a selective inhibitor of intracellular TG hydrolysis/lipolysis, is a direct target gene of LXRα. Transcriptional activation is conferred by LXRα binding to a direct repeat 4 (DR4) motif in the G0S2 promoter. While LXRα-/- mice exhibited decreased hepatic G0S2 expression, adenoviral expression of G0S2 was sufficient to restore fasting-induced TG storage and glycogen depletion in the liver of these mice. In response to LXR agonist T0901317, G0S2 ablation prevented hepatic steatosis and hypertriglyceridemia without affecting the beneficial effects on HDL. Thus, the LXRα-G0S2 axis plays a distinct role in regulating hepatic TG during both fasting and pharmacological activation of LXR.
Collapse
Affiliation(s)
- Bradlee L Heckmann
- Department of Biochemistry and Molecular Biology.,HEALth Program, Mayo Clinic in Arizona, Scottsdale, Arizona, USA.,Mayo Graduate School, Rochester, Minnesota, USA
| | - Xiaodong Zhang
- Department of Biochemistry and Molecular Biology.,HEALth Program, Mayo Clinic in Arizona, Scottsdale, Arizona, USA
| | - Alicia M Saarinen
- Department of Biochemistry and Molecular Biology.,HEALth Program, Mayo Clinic in Arizona, Scottsdale, Arizona, USA
| | - Gabriele Schoiswohl
- Division of Endocrinology, Department of Medicine, University of Pittsburgh, Pittsburgh, Pennsylvania, USA
| | - Erin E Kershaw
- Division of Endocrinology, Department of Medicine, University of Pittsburgh, Pittsburgh, Pennsylvania, USA
| | - Rudolf Zechner
- Institute of Molecular Biosciences, University of Graz, Graz, Austria
| | - Jun Liu
- Department of Biochemistry and Molecular Biology.,HEALth Program, Mayo Clinic in Arizona, Scottsdale, Arizona, USA.,Division of Endocrinology, Mayo Clinic in Arizona, Scottsdale, Arizona, USA
| |
Collapse
|
108
|
Zhang P, Chu T, Dedousis N, Mantell BS, Sipula I, Li L, Bunce KD, Shaw PA, Katz LS, Zhu J, Argmann C, O'Doherty RM, Peters DG, Scott DK. DNA methylation alters transcriptional rates of differentially expressed genes and contributes to pathophysiology in mice fed a high fat diet. Mol Metab 2017; 6:327-339. [PMID: 28377872 PMCID: PMC5369282 DOI: 10.1016/j.molmet.2017.02.001] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/30/2016] [Revised: 01/23/2017] [Accepted: 02/01/2017] [Indexed: 12/18/2022] Open
Abstract
OBJECTIVE Overnutrition can alter gene expression patterns through epigenetic mechanisms that may persist through generations. However, it is less clear if overnutrition, for example a high fat diet, modifies epigenetic control of gene expression in adults, or by what molecular mechanisms, or if such mechanisms contribute to the pathology of the metabolic syndrome. Here we test the hypothesis that a high fat diet alters hepatic DNA methylation, transcription and gene expression patterns, and explore the contribution of such changes to the pathophysiology of obesity. METHODS RNA-seq and targeted high-throughput bisulfite DNA sequencing were used to undertake a systematic analysis of the hepatic response to a high fat diet. RT-PCR, chromatin immunoprecipitation and in vivo knockdown of an identified driver gene, Phlda1, were used to validate the results. RESULTS A high fat diet resulted in the hypermethylation and decreased transcription and expression of Phlda1 and several other genes. A subnetwork of genes associated with Phlda1 was identified from an existing Bayesian gene network that contained numerous hepatic regulatory genes involved in lipid and body weight homeostasis. Hepatic-specific depletion of Phlda1 in mice decreased expression of the genes in the subnetwork, and led to increased oil droplet size in standard chow-fed mice, an early indicator of steatosis, validating the contribution of this gene to the phenotype. CONCLUSIONS We conclude that a high fat diet alters the epigenetics and transcriptional activity of key hepatic genes controlling lipid homeostasis, contributing to the pathophysiology of obesity.
Collapse
Affiliation(s)
- Pili Zhang
- Diabetes, Obesity and Metabolism Institute, Icahn School of Medicine at Mount Sinai, New York, NY, USA
| | - Tianjiao Chu
- Department of Obstetrics, Gynecology and Reproductive Sciences, University of Pittsburgh, Pittsburgh, PA, USA; Center for Fetal Medicine, Magee-Women's Research Institute, Pittsburgh, PA, USA
| | - N Dedousis
- Division of Endocrinology and Metabolism, Department of Medicine, University of Pittsburgh, Pittsburgh, PA, USA
| | - Benjamin S Mantell
- Division of Endocrinology and Metabolism, Department of Medicine, University of Pittsburgh, Pittsburgh, PA, USA
| | - Ian Sipula
- Division of Endocrinology and Metabolism, Department of Medicine, University of Pittsburgh, Pittsburgh, PA, USA
| | - Lucy Li
- Diabetes, Obesity and Metabolism Institute, Icahn School of Medicine at Mount Sinai, New York, NY, USA
| | - Kimberly D Bunce
- Department of Obstetrics, Gynecology and Reproductive Sciences, University of Pittsburgh, Pittsburgh, PA, USA; Center for Fetal Medicine, Magee-Women's Research Institute, Pittsburgh, PA, USA
| | - Patricia A Shaw
- Department of Obstetrics, Gynecology and Reproductive Sciences, University of Pittsburgh, Pittsburgh, PA, USA; Center for Fetal Medicine, Magee-Women's Research Institute, Pittsburgh, PA, USA
| | - Liora S Katz
- Diabetes, Obesity and Metabolism Institute, Icahn School of Medicine at Mount Sinai, New York, NY, USA
| | - Jun Zhu
- Department of Genetics and Genomic Sciences and Icahn Institute for Genomics and Multiscale Biology, Icahn School of Medicine at Mount Sinai, New York, NY, USA
| | - Carmen Argmann
- Department of Genetics and Genomic Sciences and Icahn Institute for Genomics and Multiscale Biology, Icahn School of Medicine at Mount Sinai, New York, NY, USA
| | - Robert M O'Doherty
- Division of Endocrinology and Metabolism, Department of Medicine, University of Pittsburgh, Pittsburgh, PA, USA
| | - David G Peters
- Department of Obstetrics, Gynecology and Reproductive Sciences, University of Pittsburgh, Pittsburgh, PA, USA; Center for Fetal Medicine, Magee-Women's Research Institute, Pittsburgh, PA, USA.
| | - Donald K Scott
- Diabetes, Obesity and Metabolism Institute, Icahn School of Medicine at Mount Sinai, New York, NY, USA.
| |
Collapse
|
109
|
Stein S, Lemos V, Xu P, Demagny H, Wang X, Ryu D, Jimenez V, Bosch F, Lüscher TF, Oosterveer MH, Schoonjans K. Impaired SUMOylation of nuclear receptor LRH-1 promotes nonalcoholic fatty liver disease. J Clin Invest 2017; 127:583-592. [PMID: 28094767 DOI: 10.1172/jci85499] [Citation(s) in RCA: 41] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2015] [Accepted: 11/22/2016] [Indexed: 12/17/2022] Open
Abstract
Hepatic steatosis is caused by metabolic imbalances that could be explained in part by an increase in de novo lipogenesis that results from increased sterol element binding protein 1 (SREBP-1) activity. The nuclear receptor liver receptor homolog 1 (LRH-1) is an important regulator of intermediary metabolism in the liver, but its role in regulating lipogenesis is not well understood. Here, we have assessed the contribution of LRH-1 SUMOylation to the development of nonalcoholic fatty liver disease (NAFLD). Mice expressing a SUMOylation-defective mutant of LRH-1 (LRH-1 K289R mice) developed NAFLD and early signs of nonalcoholic steatohepatitis (NASH) when challenged with a lipogenic, high-fat, high-sucrose diet. Moreover, we observed that the LRH-1 K289R mutation induced the expression of oxysterol binding protein-like 3 (OSBPL3), enhanced SREBP-1 processing, and promoted de novo lipogenesis. Mechanistically, we demonstrated that ectopic expression of OSBPL3 facilitates SREBP-1 processing in WT mice, while silencing hepatic Osbpl3 reverses the lipogenic phenotype of LRH-1 K289R mice. These findings suggest that compromised SUMOylation of LRH-1 promotes the development of NAFLD under lipogenic conditions through regulation of OSBPL3.
Collapse
|
110
|
Munkacsi AB, Hammond N, Schneider RT, Senanayake DS, Higaki K, Lagutin K, Bloor SJ, Ory DS, Maue RA, Chen FW, Hernandez-Ono A, Dahlson N, Repa JJ, Ginsberg HN, Ioannou YA, Sturley SL. Normalization of Hepatic Homeostasis in the Npc1nmf164 Mouse Model of Niemann-Pick Type C Disease Treated with the Histone Deacetylase Inhibitor Vorinostat. J Biol Chem 2016; 292:4395-4410. [PMID: 28031458 DOI: 10.1074/jbc.m116.770578] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2016] [Revised: 12/21/2016] [Indexed: 12/31/2022] Open
Abstract
Niemann-Pick type C (NP-C) disease is a fatal genetic lipidosis for which there is no Food and Drug Administration (FDA)-approved therapy. Vorinostat, an FDA-approved inhibitor of histone deacetylases, ameliorates lysosomal lipid accumulation in cultured NP-C patient fibroblasts. To assess the therapeutic potential of histone deacetylase inhibition, we pursued these in vitro observations in two murine models of NP-C disease. Npc1nmf164 mice, which express a missense mutation in the Npc1 gene, were treated intraperitoneally, from weaning, with the maximum tolerated dose of vorinostat (150 mg/kg, 5 days/week). Disease progression was measured via gene expression, liver function and pathology, serum and tissue lipid levels, body weight, and life span. Transcriptome analyses of treated livers indicated multiple changes consistent with reversal of liver dysfunction that typifies NP-C disease. Significant improvements in liver pathology and function were achieved by this treatment regimen; however, NPC1 protein maturation and levels, disease progression, weight loss, and animal morbidity were not detectably altered. Vorinostat concentrations were >200 μm in the plasma compartment of treated animals but were almost 100-fold lower in brain tissue. Apolipoprotein B metabolism and the expression of key components of lipid homeostasis in primary hepatocytes from null (Npc1-/-) and missense (Npc1nmf164 ) mutant mice were altered by vorinostat treatment, consistent with a response by these cells independent of the status of the Npc1 locus. These results suggest that HDAC inhibitors have utility to treat visceral NP-C disease. However, it is clear that improved blood-brain barrier penetration will be required to alleviate the neurological symptoms of human NP-C disease.
Collapse
Affiliation(s)
- Andrew B Munkacsi
- From the School of Biological Sciences and .,Centre for Biodiscovery, Victoria University of Wellington, Wellington 6012, New Zealand
| | | | | | | | - Katsumi Higaki
- the Division of Functional Genomics, Research Center for Bioscience and Technology, Tottori University, Yonago 683-8503, Japan
| | | | | | - Daniel S Ory
- the Department of Medicine, Washington University School of Medicine, St. Louis, Missouri 63110
| | - Robert A Maue
- the Department of Physiology and Neurobiology and the Department of Biochemistry, Geisel School of Medicine at Dartmouth, Hanover, New Hampshire 03755
| | - Fannie W Chen
- the Department of Genetics and Genomic Sciences, Mount Sinai School of Medicine, New York, New York 10029
| | | | - Nicole Dahlson
- the Departments of Physiology and Internal Medicine, University of Texas Southwestern Medical Center, Dallas, Texas 75390, and
| | - Joyce J Repa
- the Departments of Physiology and Internal Medicine, University of Texas Southwestern Medical Center, Dallas, Texas 75390, and
| | | | - Yiannis A Ioannou
- the Department of Genetics and Genomic Sciences, Mount Sinai School of Medicine, New York, New York 10029
| | - Stephen L Sturley
- the Department of Genetics and Development, Columbia University Medical Center, New York, New York 10032
| |
Collapse
|
111
|
The transcription factor carbohydrate-response element-binding protein (ChREBP): A possible link between metabolic disease and cancer. Biochim Biophys Acta Mol Basis Dis 2016; 1863:474-485. [PMID: 27919710 DOI: 10.1016/j.bbadis.2016.11.029] [Citation(s) in RCA: 49] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2016] [Revised: 11/24/2016] [Accepted: 11/29/2016] [Indexed: 12/19/2022]
Abstract
Carbohydrate-response element-binding protein (ChREBP) has been identified as a transcription factor that binds to carbohydrate response element in the promoter of pyruvate kinase, liver and red blood cells. ChREBP is activated by metabolites derived from glucose and suppressed by adenosine monophosphate (AMP), ketone bodies and cyclic cAMP. ChREBP regulates gene transcription related to glucose and lipid metabolism. Findings from knockout mice and human subjects suggest that ChREBP helps to induce hepatic steatosis, dyslipidemia, and glucose intolerance. Moreover, in tumor cells, ChREBP promotes aerobic glycolysis through p53 inhibition, resulting in tumor cell proliferation. Anti-diabetic and anti-lipidemic drugs such as atorvastatin, metformin, bile acid sequestrants, docosahexaenoic acid and eicosapentaenoic acid may affect ChREBP transactivity. Secretory proteins such as fibroblast growth factor 21 and ANGPTL8 (Betatrophin) may be promising candidates for biologic markers reflecting ChREBP transactivity. Thus, ChREBP is associated with metabolic diseases and cancers, and may be a link between them.
Collapse
|
112
|
Wooten JS, Nick TN, Seija A, Poole KE, Stout KB. High-Fructose Intake Impairs the Hepatic Hypolipidemic Effects of a High-Fat Fish-Oil Diet in C57BL/6 Mice. J Clin Exp Hepatol 2016; 6:265-274. [PMID: 28003715 PMCID: PMC5157917 DOI: 10.1016/j.jceh.2016.09.001] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/28/2016] [Accepted: 09/01/2016] [Indexed: 12/12/2022] Open
Abstract
BACKGROUND Overnutrition of saturated fats and fructose is one of the major factors for the development of nonalcoholic fatty liver disease. Because omega-3 polyunsaturated fatty acids (n-3fa) have established lipid lowering properties, we tested the hypothesis that n-3fa prevents high-fat and fructose-induced fatty liver disease in mice. METHODS Male C57BL/6J mice were randomly assigned to one of the following diet groups for 14 weeks: normal diet (ND), high-fat lard-based diet (HFD), HFD with fructose (HFD + Fru), high-fat fish-oil diet (FOD), or FOD + Fru. RESULTS Despite for the development of obesity and insulin resistance, FOD had 65.3% lower (P < 0.001) hepatic triglyceride levels than HFD + Fru, which was blunted to a 38.5% difference (P = 0.173) in FOD + Fru. The lower hepatic triglyceride levels were associated with a lower expression of lipogenic genes LXRα and FASN, as well as the expression of genes associated with fatty acid uptake and triglyceride synthesis, CD36 and SCD1, respectively. Conversely, the blunted hypotriglyceride effect of FOD + Fru was associated with a higher expression of CD36 and SCD1. CONCLUSIONS During overnutrition, a diet rich in n-3fa may prevent the severity of hepatic steatosis; however, when juxtaposed with a diet high in fructose, the deleterious effects of overnutrition blunted the hypolipidemic effects of n-3fa.
Collapse
Key Words
- ACC1, acetyl-CoA carboxylase-1
- CPT1a, carnitine palmitoyltransferase 1a
- ChREBP, carbohydrate response element binding protein
- FASN, fatty acid synthase
- FFA, free fatty acid
- LPL, lipoprotein lipase
- LXRα, liver-X-receptor
- MTTP, microsomal triglyceride transfer protein
- NAFLD, nonalcoholic fatty liver disease
- PPARα, peroxisome proliferator activated receptor α
- PPARγ, peroxisome proliferator activated receptor γ
- SCD1, stearoyl-CoA desaturase 1
- SREBP1c, sterol response element binding protein
- T2DM, type 2 diabetes mellitus
- TRL, triglyceride-rich lipoproteins
- VLDL, very low-density lipoprotein
- fructose
- lipid metabolism
- lipotoxicity
- n-3fa, omega-3 polyunsaturated fatty acids
- omega-3 polyunsaturated fatty acids
- overnutrition
Collapse
Affiliation(s)
- Joshua S. Wooten
- Address for correspondence: Joshua S. Wooten, Department of Applied Health, Southern Illinois University Edwardsville, Campus Box 1126, Edwardsville, IL 62026-1126, United States. Fax: +1 618 650 3719.Department of Applied Health, Southern Illinois University EdwardsvilleCampus Box 1126EdwardsvilleIL62026-1126United States
| | | | | | | | | |
Collapse
|
113
|
Hua ZG, Xiong LJ, Yan C, Wei DH, YingPai Z, Qing ZY, Lin QZ, Fei FR, Ling WY, Ren MZ. Glucose and Insulin Stimulate Lipogenesis in Porcine Adipocytes: Dissimilar and Identical Regulation Pathway for Key Transcription Factors. Mol Cells 2016; 39:797-806. [PMID: 27871177 PMCID: PMC5125935 DOI: 10.14348/molcells.2016.0144] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2016] [Revised: 10/04/2016] [Accepted: 10/20/2016] [Indexed: 01/13/2023] Open
Abstract
Lipogenesis is under the concerted action of ChREBP, SREBP-1c and other transcription factors in response to glucose and insulin. The isolated porcine preadipocytes were differentiated into mature adipocytes to investigate the roles and interrelation of these transcription factors in the context of glucose- and insulin-induced lipogenesis in pigs. In ChREBP-silenced adipocytes, glucose-induced lipogenesis decreased by ~70%, however insulin-induced lipogenesis was unaffected. Moreover, insulin had no effect on ChREBP expression of unperturbed adipocytes irrespective of glucose concentration, suggesting ChREBP mediate glucose-induced lipogenesis. Insulin stimulated SREBP-1c expression and when SREBP-1c activation was blocked, and the insulin-induced lipogenesis decreased by ~55%, suggesting SREBP-1c is a key transcription factor mediating insulin-induced lipogenesis. LXRα activation promoted lipogenesis and lipogenic genes expression. In ChREBP-silenced or SREBP-1c activation blocked adipocytes, LXRα activation facilitated lipogenesis and SREBP-1c expression, but had no effect on ChREBP expression. Therefore, LXRα might mediate lipogenesis via SREBP-1c rather than ChREBP. When ChREBP expression was silenced and SREBP-1c activation blocked simultaneously, glucose and insulin were still able to stimulated lipogenesis and lipogenic genes expression, and LXRα activation enhanced these effects, suggesting LXRα mediated directly glucose- and insulin-induced lipogenesis. In summary, glucose and insulin stimulated lipogenesis through both dissimilar and identical regulation pathway in porcine adipocytes.
Collapse
Affiliation(s)
- Zhang Guo Hua
- College of Life Science and Engineering, Northwest University for Nationalities, Lanzhou, Gansu 730030,
China
| | - Lu Jian Xiong
- College of Life Science and Engineering, Northwest University for Nationalities, Lanzhou, Gansu 730030,
China
| | - Chen Yan
- College of Life Science and Engineering, Northwest University for Nationalities, Lanzhou, Gansu 730030,
China
| | - Dai Hong Wei
- College of Life Science and Engineering, Northwest University for Nationalities, Lanzhou, Gansu 730030,
China
| | - ZhaXi YingPai
- College of Life Science and Engineering, Northwest University for Nationalities, Lanzhou, Gansu 730030,
China
| | - Zhao Yong Qing
- College of Life Science and Engineering, Northwest University for Nationalities, Lanzhou, Gansu 730030,
China
| | - Qiao Zi Lin
- Gansu Engineering Research Center for Animal Cell, Northwest University for Nationalities, Lanzhou, Gansu 730030,
China
| | - Feng Ruo Fei
- Gansu Engineering Research Center for Animal Cell, Northwest University for Nationalities, Lanzhou, Gansu 730030,
China
| | - Wang Ya Ling
- College of Life Science and Engineering, Northwest University for Nationalities, Lanzhou, Gansu 730030,
China
| | - Ma Zhong Ren
- Gansu Engineering Research Center for Animal Cell, Northwest University for Nationalities, Lanzhou, Gansu 730030,
China
| |
Collapse
|
114
|
Fasting and Feeding Signals Control the Oscillatory Expression of Angptl8 to Modulate Lipid Metabolism. Sci Rep 2016; 6:36926. [PMID: 27845381 PMCID: PMC5109406 DOI: 10.1038/srep36926] [Citation(s) in RCA: 36] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2016] [Accepted: 10/24/2016] [Indexed: 12/27/2022] Open
Abstract
Emerging evidence implies a key role of angiopoietin-like protein 8 (Angptl8) in the metabolic transition between fasting and feeding, whereas much less is known about the mechanism of its own expression. Here we show that hepatic Angptl8 is rhythmically expressed, which involving the liver X receptor alpha (LXRα) and glucocorticoid receptor (GR) modulation during feeding and fasting periods, respectively. In addition, Angptl8 mRNA is very unstable, which contributes to the nature of its daily rhythmicity by rapidly responding to fasting/feeding transition. To explore its pathological function in dexamethasone (DEX)-induced fatty liver, we reversed its suppression by glucocorticoids through adenoviral delivery of Angptl8 gene in mouse liver. Surprisingly, hepatic overexpression of Angptl8 dramatically elevated plasma triglyceride (TG) and non-esterified fatty acid (NEFA) levels in DEX-treated mice, suggesting a metabolic interaction between Angptl8 and glucocorticoid signaling. Moreover, intracellular hepatic Angptl8 is implicated in the regulation of lipid homeostasis by the experiments with ectopic expression of a nonsecreted Angptl8 mutant (Δ25-Angptl8). Altogether, our data demonstrate the molecular mechanism of the diurnal rhythm of Angptl8 expression regulated by glucocorticoid signaling and LXRα pathway, and provide new evidence to understand the role of Angptl8 in maintaining plasma TG homeostasis.
Collapse
|
115
|
Hu W, Zhang W, Chen Y, Rana U, Teng RJ, Duan Y, Liu Z, Zhao B, Foeckler J, Weiler H, Kallinger RE, Thomas MJ, Zhang K, Han J, Miao QR. Nogo-B receptor deficiency increases liver X receptor alpha nuclear translocation and hepatic lipogenesis through an adenosine monophosphate-activated protein kinase alpha-dependent pathway. Hepatology 2016; 64:1559-1576. [PMID: 27480224 PMCID: PMC5074877 DOI: 10.1002/hep.28747] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/15/2015] [Revised: 06/30/2016] [Accepted: 07/14/2016] [Indexed: 01/01/2023]
Abstract
UNLABELLED Nogo-B receptor (NgBR) was identified as a specific receptor for binding Nogo-B and is essential for the stability of Niemann-Pick type C2 protein (NPC2) and NPC2-dependent cholesterol trafficking. Here, we report that NgBR expression levels decrease in the fatty liver and that NgBR plays previously unrecognized roles in regulating hepatic lipogenesis through NPC2-independent pathways. To further elucidate the pathophysiological role of NgBR in mammals, we generated NgBR liver-specific knockout mice and investigated the roles of NgBR in hepatic lipid homeostasis. The results showed that NgBR knockout in mouse liver did not decrease NPC2 levels or increase NPC2-dependent intracellular cholesterol levels. However, NgBR deficiency still resulted in remarkable cellular lipid accumulation that was associated with increased free fatty acids and triglycerides in hepatocytes in vitro and in mouse livers in vivo. Mechanistically, NgBR deficiency specifically promotes the nuclear translocation of the liver X receptor alpha (LXRα) and increases the expression of LXRα-targeted lipogenic genes. LXRα knockout attenuates the accumulation of free fatty acids and triglycerides caused by NgBR deficiency. In addition, we elucidated the mechanisms by which NgBR bridges the adenosine monophosphate-activated protein kinase alpha signaling pathway with LXRα nuclear translocation and LXRα-mediated lipogenesis. CONCLUSION NgBR is a specific negative regulator for LXRα-dependent hepatic lipogenesis. Loss of NgBR may be a potential trigger for inducing hepatic steatosis. (Hepatology 2016;64:1559-1576).
Collapse
Affiliation(s)
- Wenquan Hu
- Department of Surgery and Pathology, Medical College of Wisconsin
,State Key Laboratory of Medicinal Chemical Biology, Nankai University, Tianjin 300071, China
| | - Wenwen Zhang
- State Key Laboratory of Medicinal Chemical Biology, Nankai University, Tianjin 300071, China
| | - Yuanli Chen
- State Key Laboratory of Medicinal Chemical Biology, Nankai University, Tianjin 300071, China
| | - Ujala Rana
- Department of Surgery and Pathology, Medical College of Wisconsin
| | - Ru-jeng Teng
- Department of Pediatrics, Children’s Research Institute, Medical College of Wisconsin
| | - Yajun Duan
- State Key Laboratory of Medicinal Chemical Biology, Nankai University, Tianjin 300071, China
| | - Zhong Liu
- Department of Surgery and Pathology, Medical College of Wisconsin
| | - Baofeng Zhao
- Department of Surgery and Pathology, Medical College of Wisconsin
| | | | | | | | - Michael J. Thomas
- Department of Pharmacology and Toxicology, Medical College of Wisconsin
| | - Kezhong Zhang
- Center for Molecular Medicine and Genetics, Wayne State University, Detroit, MI 48201, USA
| | - Jihong Han
- State Key Laboratory of Medicinal Chemical Biology, Nankai University, Tianjin, China. .,College of Biomedical Engineering, Hefei University of Technology, Hefei, China.
| | - Qing Robert Miao
- Departments of Surgery and Pathology, Children's Research Institute, Medical College of Wisconsin, Milwaukee, WI.
| |
Collapse
|
116
|
Tan NS, Vázquez-Carrera M, Montagner A, Sng MK, Guillou H, Wahli W. Transcriptional control of physiological and pathological processes by the nuclear receptor PPARβ/δ. Prog Lipid Res 2016; 64:98-122. [PMID: 27665713 DOI: 10.1016/j.plipres.2016.09.001] [Citation(s) in RCA: 51] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2016] [Revised: 08/31/2016] [Accepted: 09/20/2016] [Indexed: 12/14/2022]
Affiliation(s)
- Nguan Soon Tan
- School of Biological Sciences, Nanyang Technological University, 60 Nanyang Drive, 637551, Singapore; Lee Kong Chian School of Medicine, Nanyang Technological University, Academia, 20 College Road, 169856, Singapore; Institute of Molecular and Cell Biology, 61 Biopolis Drive, Proteos, Agency for Science Technology & Research, 138673, Singapore; KK Research Centre, KK Women's and Children's Hospital, 100 Bukit Timah Road, 229899, Singapore.
| | - Manuel Vázquez-Carrera
- Department of Pharmacology and Therapeutic Chemistry, Faculty of Pharmacy, University of Barcelona, Institute of Biomedicine of the University of Barcelona (IBUB), Pediatric Research Institute-Hospital Sant Joan de Déu, Spanish Biomedical Research Centre in Diabetes and Associated Metabolic Diseases (CIBERDEM), Barcelona, Spain
| | | | - Ming Keat Sng
- School of Biological Sciences, Nanyang Technological University, 60 Nanyang Drive, 637551, Singapore; Lee Kong Chian School of Medicine, Nanyang Technological University, Academia, 20 College Road, 169856, Singapore
| | - Hervé Guillou
- INRA ToxAlim, UMR1331, Chemin de Tournefeuille, Toulouse Cedex 3, France
| | - Walter Wahli
- Lee Kong Chian School of Medicine, Nanyang Technological University, Academia, 20 College Road, 169856, Singapore; INRA ToxAlim, UMR1331, Chemin de Tournefeuille, Toulouse Cedex 3, France; Center for Integrative Genomics, University of Lausanne, Le Génopode, CH 1015 Lausanne, Switzerland.
| |
Collapse
|
117
|
Baldini SF, Wavelet C, Hainault I, Guinez C, Lefebvre T. The Nutrient-Dependent O -GlcNAc Modification Controls the Expression of Liver Fatty Acid Synthase. J Mol Biol 2016; 428:3295-3304. [DOI: 10.1016/j.jmb.2016.04.035] [Citation(s) in RCA: 37] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2016] [Revised: 04/27/2016] [Accepted: 04/29/2016] [Indexed: 12/13/2022]
|
118
|
Wang X, Li C, Xu S, Ishfaq M, Zhang X. NF-E2-related factor 2 deletion facilitates hepatic fatty acids metabolism disorder induced by high-fat diet via regulating related genes in mice. Food Chem Toxicol 2016; 94:186-96. [DOI: 10.1016/j.fct.2016.06.011] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2015] [Revised: 05/25/2016] [Accepted: 06/10/2016] [Indexed: 01/06/2023]
|
119
|
Mahmood S, Birkaya B, Rideout TC, Patel MS. Lack of mitochondria-generated acetyl-CoA by pyruvate dehydrogenase complex downregulates gene expression in the hepatic de novo lipogenic pathway. Am J Physiol Endocrinol Metab 2016; 311:E117-27. [PMID: 27166281 PMCID: PMC4967143 DOI: 10.1152/ajpendo.00064.2016] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/19/2016] [Accepted: 05/03/2016] [Indexed: 12/20/2022]
Abstract
During the absorptive state, the liver stores excess glucose as glycogen and synthesizes fatty acids for triglyceride synthesis for export as very low density lipoproteins. For de novo synthesis of fatty acids from glucose, the mitochondrial pyruvate dehydrogenase complex (PDC) is the gatekeeper for the generation of acetyl-CoA from glucose-derived pyruvate. Here, we tested the hypothesis that limiting the supply of PDC-generated acetyl-CoA from glucose would have an impact on expression of key genes in the lipogenic pathway. In the present study, although the postnatal growth of liver-specific PDC-deficient (L-PDCKO) male mice was largely unaltered, the mice developed hyperinsulinemia with lower blood glucose levels in the fed state. Serum and liver lipid triglyceride and cholesterol levels remained unaltered in L-PDCKO mice. Expression of several key genes (ACL, ACC1) in the lipogenic pathway and their upstream regulators (LXR, SREBP1, ChREBP) as well as several genes in glucose metabolism (Pklr, G6pd2, Pck1) and fatty acid oxidation (FAT, Cpt1a) was downregulated in livers from L-PDCKO mice. Interestingly, there was concomitant upregulation of lipogenic genes in adipose tissue from L-PDCKO mice. Although, the total hepatic acetyl-CoA content remained unaltered in L-PDCKO mice, modified acetylation profiles of proteins in the nuclear compartment suggested an important role for PDC-generated acetyl-CoA in gene expression in de novo fatty acid synthesis in the liver. This finding has important implications for the regulation of hepatic lipid synthesis in pathological states.
Collapse
Affiliation(s)
- Saleh Mahmood
- Department of Biochemistry, Jacobs School of Medicine and Biomedical Sciences, and
| | - Barbara Birkaya
- Department of Biochemistry, Jacobs School of Medicine and Biomedical Sciences, and
| | - Todd C Rideout
- Department of Exercise and Nutrition Sciences, School of Public Health and Health Professions, University at Buffalo, Buffalo, New York
| | - Mulchand S Patel
- Department of Biochemistry, Jacobs School of Medicine and Biomedical Sciences, and
| |
Collapse
|
120
|
|
121
|
Gao LL, Li M, Wang Q, Liu SA, Zhang JQ, Cheng J. HCBP6 Modulates Triglyceride Homeostasis in Hepatocytes Via the SREBP1c/FASN Pathway. J Cell Biochem 2016; 116:2375-84. [PMID: 25855506 DOI: 10.1002/jcb.25188] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2015] [Accepted: 04/03/2015] [Indexed: 02/06/2023]
Abstract
Hypertriglyceridemia leads to liver steatosis, cardiovascular disease, and type 2 diabetes. Although HCBP6 (hepatitis C virus core-binding protein 6) was previously shown to be an HCV (hepatitis C virus) core-binding protein, its biological function remains unclear. Here, we demonstrate that HCBP6 negatively regulates intracellular triglyceride (TG) levels in hepatocytes. We found that bidirectional manipulation of hepatocyte HCBP6 expression by knockdown or overexpression results in increased or decreased TG accumulation, respectively. In addition, HCBP6 mRNA and protein levels exhibited significant time- and dose-dependent increases in a cellular model of lipid-overload hepatic steatosis. Furthermore, TG levels are regulated by HCBP6-sterol regulatory element binding protein 1c (SREBP1c)-mediated fatty acid synthase (FASN) expression. We also demonstrate that HCBP6 mRNA and protein expression is inhibited by microRNA-122 (miR-122), and miR-122 overexpression elicited more robust translational repression of luciferase activity driven by the full 3'-UTR of HCBP6. Taken together, our results provide new evidence that miR-122-regulated HCBP6 functions as a sensor protein to maintain intrahepatocyte TG levels.
Collapse
Affiliation(s)
- Li-Li Gao
- Institute of Infectious Diseases, Beijing Ditan Hospital, Capital Medical University, Beijing, 100015, China.,Beijing Key Laboratory of Emerging Infectious Diseases, Beijing, 100015, China
| | - Min Li
- The First Hospital of Lanzhou University, Gansu Province, Gansu, 730000, China
| | - Qi Wang
- Institute of Infectious Diseases, Beijing Ditan Hospital, Capital Medical University, Beijing, 100015, China.,Beijing Key Laboratory of Emerging Infectious Diseases, Beijing, 100015, China
| | - Shun-Ai Liu
- Institute of Infectious Diseases, Beijing Ditan Hospital, Capital Medical University, Beijing, 100015, China.,Beijing Key Laboratory of Emerging Infectious Diseases, Beijing, 100015, China
| | - Jin-Qian Zhang
- Institute of Infectious Diseases, Beijing Ditan Hospital, Capital Medical University, Beijing, 100015, China.,Beijing Key Laboratory of Emerging Infectious Diseases, Beijing, 100015, China
| | - Jun Cheng
- Institute of Infectious Diseases, Beijing Ditan Hospital, Capital Medical University, Beijing, 100015, China.,Beijing Key Laboratory of Emerging Infectious Diseases, Beijing, 100015, China
| |
Collapse
|
122
|
Stevenson JL, Miller MK, Skillman HE, Paton CM, Cooper JA. A PUFA-rich diet improves fat oxidation following saturated fat-rich meal. Eur J Nutr 2016; 56:1845-1857. [PMID: 27193583 DOI: 10.1007/s00394-016-1226-9] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2016] [Accepted: 05/08/2016] [Indexed: 01/22/2023]
Abstract
PURPOSE To determine substrate oxidation responses to saturated fatty acid (SFA)-rich meals before and after a 7-day polyunsaturated fatty acid (PUFA)-rich diet versus control diet. METHODS Twenty-six, normal-weight, adults were randomly assigned to either PUFA or control diet. Following a 3-day lead-in diet, participants completed the pre-diet visit where anthropometrics and resting metabolic rate (RMR) were measured, and two SFA-rich HF meals (breakfast and lunch) were consumed. Indirect calorimetry was used to determine fat oxidation (Fox) and energy expenditure (EE) for 4 h after each meal. Participants then consumed a PUFA-rich diet (50 % carbohydrate, 15 % protein, 35 % fat, of which 21 % of total energy was PUFA) or control diet (50 % carbohydrate, 15 % protein, 35 % fat, of which 7 % of total energy was PUFA) for the next 7 days. Following the 7-day diet, participants completed the post-diet visit. RESULTS From pre- to post-PUFA-rich diet, there was no change in RMR (16.3 ± 0.8 vs. 16.4 ± 0.8 kcal/20 min) or in incremental area under the curve for EE (118.9 ± 20.6-126.9 ± 14.1 kcal/8h, ns). Fasting respiratory exchange ratio increased from pre- to post-PUFA-rich diet only (0.83 ± 0.1-0.86 ± 0.1, p < 0.05). The postprandial change in Fox increased from pre- to post-visit in PUFA-rich diet (0.03 ± 0.1-0.23 ± 0.1 g/15 min for cumulative Fox; p < 0.05), whereas controls showed no change. CONCLUSIONS Adopting a PUFA-rich diet initiates greater fat oxidation after eating occasional high SFA meals compared to a control diet, an effect achieved in 7 days.
Collapse
Affiliation(s)
- Jada L Stevenson
- Department of Nutritional Sciences, Texas Christian University, Fort Worth, TX, USA.,Department of Nutritional Sciences, Texas Tech University, Lubbock, TX, USA
| | - Mary K Miller
- Department of Nutritional Sciences, Texas Tech University, Lubbock, TX, USA
| | - Hannah E Skillman
- Department of Nutritional Sciences, Texas Tech University, Lubbock, TX, USA
| | - Chad M Paton
- Department of Food Science and Technology, University of Georgia, Athens, GA, USA.,Department of Foods and Nutrition, University of Georgia, 305 Sanford Drive, Athens, GA, 30622, USA
| | - Jamie A Cooper
- Department of Foods and Nutrition, University of Georgia, 305 Sanford Drive, Athens, GA, 30622, USA.
| |
Collapse
|
123
|
Abstract
PURPOSE OF REVIEW A low level of plasma high density lipoprotein cholesterol (HDL-C) is a strong and independent risk factor for atherosclerotic cardiovascular disease (ASCVD). However, several large studies recently revealed that pharmacologic interventions that increase HDL-C concentration have not improved cardiovascular outcomes when added to standard therapy. In addition, specific genetic variants that raise HDL-C levels are not clearly associated with reduced risk of coronary heart disease. These observations have challenged the 'HDL hypothesis' that HDL-C is causally related to ASCVD and that intervention to raise HDL-C will reduce ASCVD events. This article will present the current data on the HDL hypothesis and provide a revised paradigm of considering HDL in the atherosclerotic pathway. RECENT FINDINGS Recent evidence has shed light on the complex nature of HDL-C metabolism and function. There are compelling data that the ability of HDL to promote cholesterol efflux from macrophages, the first step in the 'reverse cholesterol transport' (RCT) pathway, is inversely associated with risk for ASCVD even after controlling for HDL-C. This has led to the 'HDL flux hypothesis' that therapeutic intervention that targets macrophage cholesterol efflux and RCT may reduce risk. Preclinical studies of such interventions show promise and early phase clinical studies, though small, are encouraging. SUMMARY The role of HDL-C in modulating atherosclerotic disease is as yet uncertain. However, new findings and therapies targeting HDL-C show early promise and may provide an important intervention in attenuating the burden of ASCVD in the future.
Collapse
|
124
|
Wang Y, Viscarra J, Kim SJ, Sul HS. Transcriptional regulation of hepatic lipogenesis. Nat Rev Mol Cell Biol 2016; 16:678-89. [PMID: 26490400 DOI: 10.1038/nrm4074] [Citation(s) in RCA: 453] [Impact Index Per Article: 56.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Fatty acid and fat synthesis in the liver is a highly regulated metabolic pathway that is important for very low-density lipoprotein (VLDL) production and thus energy distribution to other tissues. Having common features at their promoter regions, lipogenic genes are coordinately regulated at the transcriptional level. Transcription factors, such as upstream stimulatory factors (USFs), sterol regulatory element-binding protein 1C (SREBP1C), liver X receptors (LXRs) and carbohydrate-responsive element-binding protein (ChREBP) have crucial roles in this process. Recently, insights have been gained into the signalling pathways that regulate these transcription factors. After feeding, high blood glucose and insulin levels activate lipogenic genes through several pathways, including the DNA-dependent protein kinase (DNA-PK), atypical protein kinase C (aPKC) and AKT-mTOR pathways. These pathways control the post-translational modifications of transcription factors and co-regulators, such as phosphorylation, acetylation or ubiquitylation, that affect their function, stability and/or localization. Dysregulation of lipogenesis can contribute to hepatosteatosis, which is associated with obesity and insulin resistance.
Collapse
Affiliation(s)
- Yuhui Wang
- Department of Nutritional Sciences and Toxicology, University of California, Berkeley, California 94720, USA
| | - Jose Viscarra
- Department of Nutritional Sciences and Toxicology, University of California, Berkeley, California 94720, USA
| | - Sun-Joong Kim
- Department of Nutritional Sciences and Toxicology, University of California, Berkeley, California 94720, USA
| | - Hei Sook Sul
- Department of Nutritional Sciences and Toxicology, University of California, Berkeley, California 94720, USA
| |
Collapse
|
125
|
Bordicchia M, Ceresiani M, Pavani M, Minardi D, Polito M, Wabitsch M, Cannone V, Burnett JC, Dessì-Fulgheri P, Sarzani R. Insulin/glucose induces natriuretic peptide clearance receptor in human adipocytes: a metabolic link with the cardiac natriuretic pathway. Am J Physiol Regul Integr Comp Physiol 2016; 311:R104-14. [PMID: 27101299 DOI: 10.1152/ajpregu.00499.2015] [Citation(s) in RCA: 34] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2015] [Accepted: 04/12/2016] [Indexed: 11/22/2022]
Abstract
Cardiac natriuretic peptides (NP) are involved in cardiorenal regulation and in lipolysis. The NP activity is largely dependent on the ratio between the signaling receptor NPRA and the clearance receptor NPRC. Lipolysis increases when NPRC is reduced by starving or very-low-calorie diet. On the contrary, insulin is an antilipolytic hormone that increases sodium retention, suggesting a possible functional link with NP. We examined the insulin-mediated regulation of NP receptors in differentiated human adipocytes and tested the association of NP receptor expression in visceral adipose tissue (VAT) with metabolic profiles of patients undergoing renal surgery. Differentiated human adipocytes from VAT and Simpson-Golabi-Behmel Syndrome (SGBS) adipocyte cell line were treated with insulin in the presence of high-glucose or low-glucose media to study NP receptors and insulin/glucose-regulated pathways. Fasting blood samples and VAT samples were taken from patients on the day of renal surgery. We observed a potent insulin-mediated and glucose-dependent upregulation of NPRC, through the phosphatidylinositol 3-kinase pathway, associated with lower lipolysis in differentiated adipocytes. No effect was observed on NPRA. Low-glucose medium, used to simulate in vivo starving conditions, hampered the insulin effect on NPRC through modulation of insulin/glucose-regulated pathways, allowing atrial natriuretic peptide to induce lipolysis and thermogenic genes. An expression ratio in favor of NPRC in adipose tissue was associated with higher fasting insulinemia, HOMA-IR, and atherogenic lipid levels. Insulin/glucose-dependent NPRC induction in adipocytes might be a key factor linking hyperinsulinemia, metabolic syndrome, and higher blood pressure by reducing NP effects on adipocytes.
Collapse
Affiliation(s)
- M Bordicchia
- Internal Medicine and Geriatrics, Department of Clinical and Molecular Sciences, University "Politecnica delle Marche," Ancona, Italy
| | - M Ceresiani
- Internal Medicine and Geriatrics, Department of Clinical and Molecular Sciences, University "Politecnica delle Marche," Ancona, Italy
| | - M Pavani
- Internal Medicine and Geriatrics, Department of Clinical and Molecular Sciences, University "Politecnica delle Marche," Ancona, Italy
| | - D Minardi
- Department of Urology, University Politecnica delle Marche, Ancona, Italy
| | - M Polito
- Department of Urology, University Politecnica delle Marche, Ancona, Italy
| | - M Wabitsch
- Pediatric Endocrinology and Diabetes, University of Ulm, Ulm, Germany; and
| | - V Cannone
- Cardiorenal Research Laboratory, Division of Cardiovascular Diseases, Mayo Clinic, Rochester, Minnesota
| | - J C Burnett
- Cardiorenal Research Laboratory, Division of Cardiovascular Diseases, Mayo Clinic, Rochester, Minnesota
| | - P Dessì-Fulgheri
- Internal Medicine and Geriatrics, Department of Clinical and Molecular Sciences, University "Politecnica delle Marche," Ancona, Italy; Italian National Research Center on Aging INRCA-IRCCS Ospedale "U. Sestilli"
| | - R Sarzani
- Internal Medicine and Geriatrics, Department of Clinical and Molecular Sciences, University "Politecnica delle Marche," Ancona, Italy; Italian National Research Center on Aging INRCA-IRCCS Ospedale "U. Sestilli";
| |
Collapse
|
126
|
Lipid droplet-associated proteins in atherosclerosis (Review). Mol Med Rep 2016; 13:4527-34. [PMID: 27082419 PMCID: PMC4878557 DOI: 10.3892/mmr.2016.5099] [Citation(s) in RCA: 42] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2015] [Accepted: 01/29/2016] [Indexed: 01/01/2023] Open
Abstract
Accumulation of atherosclerotic plaques in arterial walls leads to major cardiovascular diseases and stroke. Macrophages/foam cells are central components of atherosclerotic plaques, which populate the arterial wall in order to remove harmful modified low‑density lipoprotein (LDL) particles, resulting in the accumulation of lipids, mostly LDL‑derived cholesterol ester, in cytosolic lipid droplets (LDs). At present, LDs are recognized as dynamic organelles that govern cellular metabolic processes. LDs consist of an inner core of neutral lipids surrounded by a monolayer of phospholipids and free cholesterol, and contain LD‑associated proteins (LDAPs) that regulate LD functions. Foam cells are characterized by an aberrant accumulation of cytosolic LDs, and are considered a hallmark of atherosclerotic lesions through all stages of development. Previous studies have investigated the mechanisms underlying foam cell formation, aiming to discover therapeutic strategies that target foam cells and intervene against atherosclerosis. It is well established that LDAPs have a major role in the pathogenesis of metabolic diseases caused by dysfunction of lipid metabolism, and several studies have linked LDAPs to the development of atherosclerosis. In this review, several foam cell‑targeting pathways have been described, with an emphasis on the role of LDAPs in cholesterol mobilization from macrophages. In addition, the potential of LDAPs as therapeutic targets to prevent the progression and/or facilitate the regression of the disease has been discussed.
Collapse
|
127
|
Identification of HNF-4α as a key transcription factor to promote ChREBP expression in response to glucose. Sci Rep 2016; 6:23944. [PMID: 27029511 PMCID: PMC4814918 DOI: 10.1038/srep23944] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2015] [Accepted: 03/16/2016] [Indexed: 01/08/2023] Open
Abstract
Transcription factor carbohydrate responsive element binding protein (ChREBP) promotes glycolysis and lipogenesis in metabolic tissues and cancer cells. ChREBP-α and ChREBP-β, two isoforms of ChREBP transcribed from different promoters, are both transcriptionally induced by glucose. However, the mechanism by which glucose increases ChREBP mRNA levels remains unclear. Here we report that hepatocyte nuclear factor 4 alpha (HNF-4α) is a key transcription factor for glucose-induced ChREBP-α and ChREBP-β expression. Ectopic HNF-4α expression increased ChREBP transcription while knockdown of HNF-4α greatly reduced ChREBP mRNA levels in liver cancer cells and mouse primary hepatocytes. HNF-4α not only directly bound to an E-box-containing region in intron 12 of the ChREBP gene, but also promoted ChREBP-β transcription by directly binding to two DR1 sites and one E-box-containing site of the ChREBP-β promoter. Moreover, HNF-4α interacted with ChREBP-α and synergistically promoted ChREBP-β transcription. Functionally, HNF-4α suppression reduced glucose-dependent ChREBP induction. Increased nuclear abundance of HNF-4α and its binding to cis-elements of ChREBP gene in response to glucose contributed to glucose-responsive ChREBP transcription. Taken together, our results not only revealed the novel mechanism by which HNF-4α promoted ChREBP transcription in response to glucose, but also demonstrated that ChREBP-α and HNF-4α synergistically increased ChREBP-β transcription.
Collapse
|
128
|
Yu S, Li S, Henke A, Muse ED, Cheng B, Welzel G, Chatterjee AK, Wang D, Roland J, Glass CK, Tremblay M. Dissociated sterol-based liver X receptor agonists as therapeutics for chronic inflammatory diseases. FASEB J 2016; 30:2570-9. [PMID: 27025962 DOI: 10.1096/fj.201600244r] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2016] [Accepted: 03/21/2016] [Indexed: 12/26/2022]
Abstract
Liver X receptor (LXR), a nuclear hormone receptor, is an essential regulator of immune responses. Activation of LXR-mediated transcription by synthetic agonists, such as T0901317 and GW3965, attenuates progression of inflammatory disease in animal models. However, the adverse effects of these conventional LXR agonists in elevating liver lipids have impeded exploitation of this intriguing mechanism for chronic therapy. Here, we explore the ability of a series of sterol-based LXR agonists to alleviate inflammatory conditions in mice without hepatotoxicity. We show that oral treatment with sterol-based LXR agonists in mice significantly reduces dextran sulfate sodium colitis-induced body weight loss, which is accompanied by reduced expression of inflammatory markers in the large intestine. The anti-inflammatory property of these agonists is recapitulated in vitro in mouse lamina propria mononuclear cells, human colonic epithelial cells, and human peripheral blood mononuclear cells. In addition, treatment with LXR agonists dramatically suppresses inflammatory cytokine expression in a model of traumatic brain injury. Importantly, in both disease models, the sterol-based agonists do not affect the liver, and the conventional agonist T0901317 results in significant liver lipid accumulation and injury. Overall, these results provide evidence for the development of sterol-based LXR agonists as novel therapeutics for chronic inflammatory diseases.-Yu, S., Li, S., Henke, A., Muse, E. D., Cheng, B., Welzel, G., Chatterjee, A. K., Wang, D., Roland, J., Glass, C. K., Tremblay, M. Dissociated sterol-based liver X receptor agonists as therapeutics for chronic inflammatory diseases.
Collapse
Affiliation(s)
- Shan Yu
- California Institute for Biomedical Research, La Jolla, California, USA
| | - Sijia Li
- California Institute for Biomedical Research, La Jolla, California, USA
| | - Adam Henke
- California Institute for Biomedical Research, La Jolla, California, USA
| | - Evan D Muse
- Department of Cellular and Molecular Medicine and Scripps Translational Science Institute, Scripps Health, La Jolla, California, USA and
| | - Bo Cheng
- California Institute for Biomedical Research, La Jolla, California, USA
| | - Gustav Welzel
- California Institute for Biomedical Research, La Jolla, California, USA
| | | | - Danling Wang
- California Institute for Biomedical Research, La Jolla, California, USA
| | - Jason Roland
- California Institute for Biomedical Research, La Jolla, California, USA
| | - Christopher K Glass
- Department of Cellular and Molecular Medicine and Department of Medicine, University of California, San Diego, La Jolla, California, USA; and
| | - Matthew Tremblay
- California Institute for Biomedical Research, La Jolla, California, USA;
| |
Collapse
|
129
|
Li S, Yuan Y, Wang T, Xu W, Li M, Mai K, Ai Q. Molecular Cloning, Functional Characterization and Nutritional Regulation of the Putative Elongase Elovl5 in the Orange-Spotted Grouper (Epinephelus coioides). PLoS One 2016; 11:e0150544. [PMID: 26950699 PMCID: PMC4780818 DOI: 10.1371/journal.pone.0150544] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2015] [Accepted: 02/15/2016] [Indexed: 01/17/2023] Open
Abstract
The enzymes involved in the biosynthesis of long-chain polyunsaturated fatty acids (LC-PUFAs) are widely studied in fish species, as fish are the main source of n-3 LC-PUFAs for human beings. In the present study, a putative gene for elovl5, which encodes a key enzyme involved in LC-PUFA synthesis, was cloned and functionally characterized, and its transcription in response to dietary n-3 LC-PUFA exposure was investigated. Moreover, cell transfection and luciferase assays were used to explore the mechanism underlying the regulation of elovl5. The full-length cDNA of elovl5 was 1242 bp (excluding the polyA tail), including an 885 bp coding region encoding a 295 amino acid protein that possesses all of the characteristic features of elovl proteins. Functional characterization of heterologously expressed grouper Elovl5 indicated that it effectively elongates both C18 (18:2n-6, 18:3n-3, 18:3n-6 and 18:4n-3) and C20 (20:4n-6 and C20:5n-3) PUFAs, but not the C22 substrates. The expression of elovl5 was significantly affected by dietary n-3 LC-PUFA exposure: a high n-3 LC-PUFA level repressed the expression of elovl5 by slightly down-regulating the expression of sterol regulatory element-binding protein (SREBP)-1 and liver X receptor (LXR) α, which are major regulators of hepatic lipid metabolism. Promoter studies showed that grouper elovl5 reporter activity was induced by over-expression of LXRα but not SREBP-1. This finding suggests that elovl5 is a direct target of LXRα, which is involved in the biosynthesis of PUFAs via transcriptional regulation of elovl5. These findings may contribute to a further understanding of the mechanism underlying the regulation of LC-PUFA biosynthesis in marine fish species.
Collapse
Affiliation(s)
- Songlin Li
- Key Laboratory of Aquaculture Nutrition and Feed, Ministry of Agriculture, Ocean University of China, Qingdao 266003, People’s Republic of China
- Key Laboratory of Mariculture, Ministry Education of China, Ocean University of China, Qingdao 266003, People’s Republic of China
- Laboratory for Marine Fisheries and Aquaculture, Qingdao National Laboratory for Marine Science and Technology, Qingdao, China
| | - Yuhui Yuan
- Key Laboratory of Aquaculture Nutrition and Feed, Ministry of Agriculture, Ocean University of China, Qingdao 266003, People’s Republic of China
- Key Laboratory of Mariculture, Ministry Education of China, Ocean University of China, Qingdao 266003, People’s Republic of China
- Laboratory for Marine Fisheries and Aquaculture, Qingdao National Laboratory for Marine Science and Technology, Qingdao, China
| | - Tianjiao Wang
- Key Laboratory of Aquaculture Nutrition and Feed, Ministry of Agriculture, Ocean University of China, Qingdao 266003, People’s Republic of China
- Key Laboratory of Mariculture, Ministry Education of China, Ocean University of China, Qingdao 266003, People’s Republic of China
- Laboratory for Marine Fisheries and Aquaculture, Qingdao National Laboratory for Marine Science and Technology, Qingdao, China
| | - Wei Xu
- Key Laboratory of Aquaculture Nutrition and Feed, Ministry of Agriculture, Ocean University of China, Qingdao 266003, People’s Republic of China
- Key Laboratory of Mariculture, Ministry Education of China, Ocean University of China, Qingdao 266003, People’s Republic of China
- Laboratory for Marine Fisheries and Aquaculture, Qingdao National Laboratory for Marine Science and Technology, Qingdao, China
| | - Mingzhu Li
- Key Laboratory of Aquaculture Nutrition and Feed, Ministry of Agriculture, Ocean University of China, Qingdao 266003, People’s Republic of China
- Key Laboratory of Mariculture, Ministry Education of China, Ocean University of China, Qingdao 266003, People’s Republic of China
- Laboratory for Marine Fisheries and Aquaculture, Qingdao National Laboratory for Marine Science and Technology, Qingdao, China
| | - Kangsen Mai
- Key Laboratory of Aquaculture Nutrition and Feed, Ministry of Agriculture, Ocean University of China, Qingdao 266003, People’s Republic of China
- Key Laboratory of Mariculture, Ministry Education of China, Ocean University of China, Qingdao 266003, People’s Republic of China
- Laboratory for Marine Fisheries and Aquaculture, Qingdao National Laboratory for Marine Science and Technology, Qingdao, China
| | - Qinghui Ai
- Key Laboratory of Aquaculture Nutrition and Feed, Ministry of Agriculture, Ocean University of China, Qingdao 266003, People’s Republic of China
- Key Laboratory of Mariculture, Ministry Education of China, Ocean University of China, Qingdao 266003, People’s Republic of China
- Laboratory for Marine Fisheries and Aquaculture, Qingdao National Laboratory for Marine Science and Technology, Qingdao, China
- * E-mail:
| |
Collapse
|
130
|
Korach-André M, Gustafsson JÅ. Liver X receptors as regulators of metabolism. Biomol Concepts 2016; 6:177-90. [PMID: 25945723 DOI: 10.1515/bmc-2015-0007] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2015] [Accepted: 04/01/2015] [Indexed: 11/15/2022] Open
Abstract
The liver X receptors (LXR) are crucial regulators of metabolism. After ligand binding, they regulate gene transcription and thereby mediate changes in metabolic pathways. Modulation of LXR and their downstream targets has appeared to be a promising treatment for metabolic diseases especially atherosclerosis and cholesterol metabolism. However, the complexity of LXR action in various metabolic tissues and the liver side effect of LXR activation have slowed down the interest for LXR drugs. In this review, we summarized the role of LXR in the main metabolically active tissues with a special focus on obesity and associated diseases in mammals. We will also discuss the dual interplay between the two LXR isoforms suggesting that they may collaborate to establish a fine and efficient system for the maintenance of metabolism homeostasis.
Collapse
|
131
|
Baldini SF, Lefebvre T. O-GlcNAcylation and the Metabolic Shift in High-Proliferating Cells: All the Evidence Suggests that Sugars Dictate the Flux of Lipid Biogenesis in Tumor Processes. Front Oncol 2016; 6:6. [PMID: 26835421 PMCID: PMC4722119 DOI: 10.3389/fonc.2016.00006] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2015] [Accepted: 01/08/2016] [Indexed: 12/25/2022] Open
Abstract
Cancer cells are characterized by their high capability to proliferate. This imposes an accelerated biosynthesis of membrane compounds to respond to the need for increasing the membrane surface of dividing cells and remodeling the structure of lipid microdomains. Recently, attention has been paid to the upregulation of O-GlcNAcylation processes observed in cancer cells. Although O-GlcNAcylation of lipogenic transcriptional regulators is described in the literature (e.g., FXR, LXR, ChREBP), little is known about the regulation of the enzymes that drive lipogenesis: acetyl co-enzyme A carboxylase and fatty acid synthase (FAS). The expression and catalytic activity of both FAS and O-GlcNAc transferase (OGT) are high in cancer cells but the reciprocal regulation of the two enzymes remains unexplored. In this perspective, we collected data linking FAS and OGT and, in so doing, pave the way for the exploration of the intricate functions of these two actors that play a central role in tumor growth.
Collapse
Affiliation(s)
- Steffi F Baldini
- University Lille, CNRS, UMR 8576, UGSF, Unité de Glycobiologie Structurale et Fonctionnelle , Lille , France
| | - Tony Lefebvre
- University Lille, CNRS, UMR 8576, UGSF, Unité de Glycobiologie Structurale et Fonctionnelle , Lille , France
| |
Collapse
|
132
|
Schmitt M, Dehay B, Bezard E, Garcia-Ladona FJ. Harnessing the trophic and modulatory potential of statins in a dopaminergic cell line. Synapse 2016; 70:71-86. [DOI: 10.1002/syn.21881] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2015] [Revised: 11/12/2015] [Accepted: 12/15/2015] [Indexed: 01/15/2023]
Affiliation(s)
- Mathieu Schmitt
- Neuroscience Therapeutic Area, New Medicines, UCB Biopharma SPRL; 1420 Braine L'alleud Belgium
- University De Bordeaux, Institut Des Maladies Neurodégénératives; UMR 5293 Bordeaux 33000 France
- CNRS, Institut Des Maladies Neurodégénératives; UMR 5293 Bordeaux 33000 France
| | - Benjamin Dehay
- University De Bordeaux, Institut Des Maladies Neurodégénératives; UMR 5293 Bordeaux 33000 France
- CNRS, Institut Des Maladies Neurodégénératives; UMR 5293 Bordeaux 33000 France
| | - Erwan Bezard
- University De Bordeaux, Institut Des Maladies Neurodégénératives; UMR 5293 Bordeaux 33000 France
- CNRS, Institut Des Maladies Neurodégénératives; UMR 5293 Bordeaux 33000 France
| | - F. Javier Garcia-Ladona
- Neuroscience Therapeutic Area, New Medicines, UCB Biopharma SPRL; 1420 Braine L'alleud Belgium
| |
Collapse
|
133
|
Boylan MO, Glazebrook PA, Tatalovic M, Wolfe MM. Gastric inhibitory polypeptide immunoneutralization attenuates development of obesity in mice. Am J Physiol Endocrinol Metab 2015; 309:E1008-18. [PMID: 26487006 DOI: 10.1152/ajpendo.00345.2015] [Citation(s) in RCA: 46] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/24/2015] [Accepted: 10/16/2015] [Indexed: 12/29/2022]
Abstract
Previous reports have suggested that the abrogation of gastric inhibitory polypeptide (GIP) signaling could be exploited to prevent and treat obesity and obesity-related disorders in humans. This study was designed to determine whether immunoneutralization of GIP, using a newly developed specific monoclonal antibody (mAb), would prevent the development of obesity. Specific mAb directed against the carboxy terminus of mouse GIP was identified, and its effects on the insulin response to oral and to intraperitoneal (ip) glucose and on weight gain were evaluated. Administration of mAb (30 mg/kg body wt, BW) to mice attenuated the insulin response to oral glucose by 70% and completely eliminated the response to ip glucose coadministered with human GIP. Nine-week-old C57BL/6 mice injected with GIP mAbs (60 mg·kg BW(-1)·wk(-1)) for 17 wk gained 46.5% less weight than control mice fed an identical high-fat diet (P < 0.001). No significant differences in the quantity of food consumed were detected between the two treatment groups. Furthermore, magnetic resonance imaging demonstrated that subcutaneous, omental, and hepatic fat were 1.97-, 3.46-, and 2.15-fold, respectively, lower in mAb-treated animals than in controls. Moreover, serum insulin, leptin, total cholesterol (TC), low-density lipoprotein (LDL), and triglycerides were significantly reduced, whereas the high-density lipoprotein (HDL)/TC ratio was 1.25-fold higher in treated animals than in controls. These studies support the hypothesis that a reduction in GIP signaling using a GIP-neutralizing mAb might provide a useful method for the treatment and prevention of obesity and related disorders.
Collapse
Affiliation(s)
- Michael O Boylan
- Division of Gastroenterology, MetroHealth Medical Center and Case Western Reserve University, Cleveland, Ohio
| | - Patricia A Glazebrook
- Division of Gastroenterology, MetroHealth Medical Center and Case Western Reserve University, Cleveland, Ohio
| | - Milos Tatalovic
- Division of Gastroenterology, MetroHealth Medical Center and Case Western Reserve University, Cleveland, Ohio
| | - M Michael Wolfe
- Division of Gastroenterology, MetroHealth Medical Center and Case Western Reserve University, Cleveland, Ohio
| |
Collapse
|
134
|
Sim WC, Kim DG, Lee KJ, Choi YJ, Choi YJ, Shin KJ, Jun DW, Park SJ, Park HJ, Kim J, Oh WK, Lee BH. Cinnamamides, Novel Liver X Receptor Antagonists that Inhibit Ligand-Induced Lipogenesis and Fatty Liver. J Pharmacol Exp Ther 2015; 355:362-369. [DOI: 10.1124/jpet.115.226738] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 08/30/2023] Open
|
135
|
Emerging role of liver X receptors in cardiac pathophysiology and heart failure. Basic Res Cardiol 2015; 111:3. [PMID: 26611207 PMCID: PMC4661180 DOI: 10.1007/s00395-015-0520-7] [Citation(s) in RCA: 46] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/11/2015] [Accepted: 11/03/2015] [Indexed: 01/09/2023]
Abstract
Liver X receptors (LXRs) are master regulators of metabolism and have been studied for their pharmacological potential in vascular and metabolic disease. Besides their established role in metabolic homeostasis and disease, there is mounting evidence to suggest that LXRs may exert direct beneficial effects in the heart. Here, we aim to provide a conceptual framework to explain the broad mode of action of LXRs and how LXR signaling may be an important local and systemic target for the treatment of heart failure. We discuss the potential role of LXRs in systemic conditions associated with heart failure, such as hypertension, diabetes, and renal and vascular disease. Further, we expound on recent data that implicate a direct role for LXR activation in the heart, for its impact on cardiomyocyte damage and loss due to ischemia, and effects on cardiac hypertrophy, fibrosis, and myocardial metabolism. Taken together, the accumulating evidence supports the notion that LXRs may represent a novel therapeutic target for the treatment of heart failure.
Collapse
|
136
|
Ge CX, Yu R, Xu MX, Li PQ, Fan CY, Li JM, Kong LD. Betaine prevented fructose-induced NAFLD by regulating LXRα/PPARα pathway and alleviating ER stress in rats. Eur J Pharmacol 2015; 770:154-64. [PMID: 26593707 DOI: 10.1016/j.ejphar.2015.11.043] [Citation(s) in RCA: 79] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2015] [Revised: 11/19/2015] [Accepted: 11/20/2015] [Indexed: 12/28/2022]
Abstract
Betaine has been proven effective in treating nonalcoholic fatty liver disease (NAFLD) in animal models, however, its molecular mechanisms remain elusive. The aims of this study were to explore the mechanisms mediating the anti-inflammatory and anti-lipogenic actions of betaine in fructose-fed rats. In this study, betaine improved insulin resistance, reduced body weight gain and serum lipid levels, and prevented hepatic lipid accumulation in fructose-fed rats. It up-regulated hepatic expression of liver X receptor-alpha (LXRα) and peroxisome proliferator-activated receptor-alpha (PPARα), with the attenuation of the changes of their target genes, including hepatic carnitine palmitoyl transferase (CPT) 1α, glycosylphosphatidylinositol anchored high density lipoprotein binding protein 1, apolipoprotein B, sterol regulatory element-binding protein 1c and adipocyte differentiation-related protein, involved in fatty acid oxidation and lipid storage in these model rats. Furthermore, betaine alleviated ER stress and inhibited acetyl-CoA carboxylase α, CPT II, stearoyl-CoA desaturase 1 and fatty acid synthase expression involved in fatty acid synthesis in the liver of fructose-fed rats. Betaine suppressed hepatic gluconeogenesis in fructose-fed rats by moderating protein kinase B -forkhead box protein O1 pathway, as well as p38 mitogen-activated protein kinase and mammalian target of rapamycin activity. Moreover, betaine inhibited hepatic nuclear factor kappa B /nucleotide-binding domain, leucine-rich-containing family, pyrin domain-containing-3 inflammasome activation-mediated inflammation in this animal model. These results demonstrated that betaine ameliorated hepatic lipid accumulation, gluconeogenesis, and inflammation through restoring LXRα and PPARα expression and alleviating ER stress in fructose-fed rats. This study provides the potential mechanisms of betaine involved in the treatment of NAFLD.
Collapse
Affiliation(s)
- Chen-Xu Ge
- State Key Laboratory of Pharmaceutical Biotechnology, School of Life Sciences, Nanjing University, Nanjing 210023, PR China
| | - Rong Yu
- State Key Laboratory of Pharmaceutical Biotechnology, School of Life Sciences, Nanjing University, Nanjing 210023, PR China
| | - Min-Xuan Xu
- State Key Laboratory of Pharmaceutical Biotechnology, School of Life Sciences, Nanjing University, Nanjing 210023, PR China
| | - Pei-Qin Li
- State Key Laboratory of Pharmaceutical Biotechnology, School of Life Sciences, Nanjing University, Nanjing 210023, PR China
| | - Chen-Yu Fan
- State Key Laboratory of Pharmaceutical Biotechnology, School of Life Sciences, Nanjing University, Nanjing 210023, PR China
| | - Jian-Mei Li
- State Key Laboratory of Pharmaceutical Biotechnology, School of Life Sciences, Nanjing University, Nanjing 210023, PR China.
| | - Ling-Dong Kong
- State Key Laboratory of Pharmaceutical Biotechnology, School of Life Sciences, Nanjing University, Nanjing 210023, PR China.
| |
Collapse
|
137
|
Abstract
Nuclear receptors are involved in many important function and mediate signaling by factors including hormones, vitamins and a number of endogenous ligands and xenobiotics, several of which are involved in lipid metabolism. This review focuses on the liver X receptor (LXR), which is an important regulator of whole-body cholesterol, fatty acid, and glucose homeostasis that binds to LXR response elements as a heterodimer with retinoid X receptors, and the farnesoid X receptor (FXR), which is a bile acid receptor involved in feedback inhibition of bile acid synthesis, and thus cholesterol catabolism. These nuclear receptors regulate gene programs that control intestinal and hepatic lipid homeostasis through their effects on cholesterol transport and catabolism.
Collapse
Affiliation(s)
- Antonio Moschetta
- Interdisciplinary Department of Medicine, Medicina Interna Universitaria "C. Frugoni", Universià di Bari "Aldo Moro", Bari, Italy.
| |
Collapse
|
138
|
Sun X, Haas ME, Miao J, Mehta A, Graham MJ, Crooke RM, Pais de Barros JP, Wang JG, Aikawa M, Masson D, Biddinger SB. Insulin Dissociates the Effects of Liver X Receptor on Lipogenesis, Endoplasmic Reticulum Stress, and Inflammation. J Biol Chem 2015; 291:1115-22. [PMID: 26511317 DOI: 10.1074/jbc.m115.668269] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2015] [Indexed: 12/24/2022] Open
Abstract
Diabetes is characterized by increased lipogenesis as well as increased endoplasmic reticulum (ER) stress and inflammation. The nuclear hormone receptor liver X receptor (LXR) is induced by insulin and is a key regulator of lipid metabolism. It promotes lipogenesis and cholesterol efflux, but suppresses endoplasmic reticulum stress and inflammation. The goal of these studies was to dissect the effects of insulin on LXR action. We used antisense oligonucleotides to knock down Lxrα in mice with hepatocyte-specific deletion of the insulin receptor and their controls. We found, surprisingly, that knock-out of the insulin receptor and knockdown of Lxrα produced equivalent, non-additive effects on the lipogenic genes. Thus, insulin was unable to induce the lipogenic genes in the absence of Lxrα, and LXRα was unable to induce the lipogenic genes in the absence of insulin. However, insulin was not required for LXRα to modulate the phospholipid profile, or to suppress genes in the ER stress or inflammation pathways. These data show that insulin is required specifically for the lipogenic effects of LXRα and that manipulation of the insulin signaling pathway could dissociate the beneficial effects of LXR on cholesterol efflux, inflammation, and ER stress from the negative effects on lipogenesis.
Collapse
Affiliation(s)
- Xiaowei Sun
- From the Division of Endocrinology, Boston Children's Hospital, Harvard Medical School, Boston, Massachusetts 02115
| | - Mary E Haas
- From the Division of Endocrinology, Boston Children's Hospital, Harvard Medical School, Boston, Massachusetts 02115
| | - Ji Miao
- From the Division of Endocrinology, Boston Children's Hospital, Harvard Medical School, Boston, Massachusetts 02115
| | - Abhiruchi Mehta
- From the Division of Endocrinology, Boston Children's Hospital, Harvard Medical School, Boston, Massachusetts 02115
| | | | | | | | - Jian-Guo Wang
- the Center for Interdisciplinary Cardiovascular Sciences, Brigham and Women's Hospital, Harvard Medical School, Boston, Massachusetts 02115
| | - Masanori Aikawa
- the Center for Interdisciplinary Cardiovascular Sciences, Brigham and Women's Hospital, Harvard Medical School, Boston, Massachusetts 02115
| | - David Masson
- the Centre de Recherche INSERM-UMR866, Université de Bourgogne, 21000 Dijon, France, and
| | - Sudha B Biddinger
- From the Division of Endocrinology, Boston Children's Hospital, Harvard Medical School, Boston, Massachusetts 02115,
| |
Collapse
|
139
|
Sarrazy V, Sore S, Viaud M, Rignol G, Westerterp M, Ceppo F, Tanti JF, Guinamard R, Gautier EL, Yvan-Charvet L. Maintenance of Macrophage Redox Status by ChREBP Limits Inflammation and Apoptosis and Protects against Advanced Atherosclerotic Lesion Formation. Cell Rep 2015; 13:132-144. [PMID: 26411684 DOI: 10.1016/j.celrep.2015.08.068] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2014] [Revised: 07/20/2015] [Accepted: 08/23/2015] [Indexed: 01/04/2023] Open
Abstract
Enhanced glucose utilization can be visualized in atherosclerotic lesions and may reflect a high glycolytic rate in lesional macrophages, but its causative role in plaque progression remains unclear. We observe that the activity of the carbohydrate-responsive element binding protein ChREBP is rapidly downregulated upon TLR4 activation in macrophages. ChREBP inactivation refocuses cellular metabolism to a high redox state favoring enhanced inflammatory responses after TLR4 activation and increased cell death after TLR4 activation or oxidized LDL loading. Targeted deletion of ChREBP in bone marrow cells resulted in accelerated atherosclerosis progression in Ldlr(-/-) mice with increased monocytosis, lesional macrophage accumulation, and plaque necrosis. Thus, ChREBP-dependent macrophage metabolic reprogramming hinders plaque progression and establishes a causative role for leukocyte glucose metabolism in atherosclerosis.
Collapse
Affiliation(s)
- Vincent Sarrazy
- Institut National de la Santé et de la Recherche Médicale (INSERM) U1065, Centre Méditerranéen de Médecine Moléculaire (C3M), Atip-Avenir, 06204 Nice, France
| | - Sophie Sore
- Institut National de la Santé et de la Recherche Médicale (INSERM) U1065, Centre Méditerranéen de Médecine Moléculaire (C3M), Atip-Avenir, 06204 Nice, France
| | - Manon Viaud
- Institut National de la Santé et de la Recherche Médicale (INSERM) U1065, Centre Méditerranéen de Médecine Moléculaire (C3M), Atip-Avenir, 06204 Nice, France
| | - Guylène Rignol
- Institut National de la Santé et de la Recherche Médicale (INSERM) U1065, Centre Méditerranéen de Médecine Moléculaire (C3M), Atip-Avenir, 06204 Nice, France
| | - Marit Westerterp
- Division of Molecular Medicine, Department of Medicine, Columbia University, New York, NY 10032, USA
| | - Franck Ceppo
- Institut National de la Santé et de la Recherche Médicale (INSERM) U1065, Centre Méditerranéen de Médecine Moléculaire (C3M), Atip-Avenir, 06204 Nice, France
| | - Jean-Francois Tanti
- Institut National de la Santé et de la Recherche Médicale (INSERM) U1065, Centre Méditerranéen de Médecine Moléculaire (C3M), Atip-Avenir, 06204 Nice, France
| | - Rodolphe Guinamard
- Institut National de la Santé et de la Recherche Médicale (INSERM) U1065, Centre Méditerranéen de Médecine Moléculaire (C3M), Atip-Avenir, 06204 Nice, France
| | - Emmanuel L Gautier
- Institut National de la Santé et de la Recherche Médicale (INSERM) UMR_S 1166, Pierre and Marie Curie University Paris 6, ICAN Institute of Cardiometabolism and Nutrition, 75006 Paris, France
| | - Laurent Yvan-Charvet
- Institut National de la Santé et de la Recherche Médicale (INSERM) U1065, Centre Méditerranéen de Médecine Moléculaire (C3M), Atip-Avenir, 06204 Nice, France.
| |
Collapse
|
140
|
Huang K, Liang XC, Zhong YL, He WY, Wang Z. 5-Caffeoylquinic acid decreases diet-induced obesity in rats by modulating PPARα and LXRα transcription. JOURNAL OF THE SCIENCE OF FOOD AND AGRICULTURE 2015; 95:1903-1910. [PMID: 25186103 DOI: 10.1002/jsfa.6896] [Citation(s) in RCA: 85] [Impact Index Per Article: 9.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/05/2014] [Revised: 08/28/2014] [Accepted: 08/29/2014] [Indexed: 06/03/2023]
Abstract
BACKGROUND Chlorogenic acids (CGAs) are widely distributed in plant material, including foods and beverages. 5-Caffeoylquinic acid (5-CQA) is the most studied CGA, but the mechanism of its hypolipidaemic effect remains unclear. This study aimed to determine the effect of 5-CQA on lipid metabolism in the liver of Sprague-Dawley rats fed a high-fat diet (HFD). RESULTS 5-CQA suppressed HFD-induced increases in body weight and visceral fat-pad weight, serum lipid levels, and serum and hepatic free fatty acids in a dose-dependent manner. Real-time polymerase chain reaction revealed that 5-CQA altered the mRNA expression of the transcription factors peroxisome proliferator-activated receptor α (PPARα) and liver X receptor α (LXRα) and target genes involved in hepatic fatty acid uptake, β-oxidation, fatty acid synthesis, and cholesterol synthesis. Moreover, hepatic tissue sections from HFD-fed rats showed many empty vacuoles, suggesting that liver cells were filled with more fat droplets. However, 5-CQA significantly ameliorated this effect. CONCLUSION 5-CQA may improve lipid metabolism disorders by altering the expression of PPARα and LXRα, which are involved in multiple intracellular signalling pathways.
Collapse
Affiliation(s)
- Kang Huang
- College of Bioscience and Biotechnology, Hunan Agricultural University, Changsha, Hunan, 410128, China
| | - Xiu-ci Liang
- College of Bioscience and Biotechnology, Hunan Agricultural University, Changsha, Hunan, 410128, China
| | - Ying-li Zhong
- College of Bioscience and Biotechnology, Hunan Agricultural University, Changsha, Hunan, 410128, China
| | - Wan-yan He
- College of Bioscience and Biotechnology, Hunan Agricultural University, Changsha, Hunan, 410128, China
| | - Zheng Wang
- College of Bioscience and Biotechnology, Hunan Agricultural University, Changsha, Hunan, 410128, China
| |
Collapse
|
141
|
Regulation of the fatty acid synthase promoter by liver X receptor α through direct and indirect mechanisms in goat mammary epithelial cells. Comp Biochem Physiol B Biochem Mol Biol 2015; 184:44-51. [DOI: 10.1016/j.cbpb.2015.02.005] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2014] [Revised: 02/20/2015] [Accepted: 02/23/2015] [Indexed: 11/20/2022]
|
142
|
Varin A, Thomas C, Ishibashi M, Ménégaut L, Gautier T, Trousson A, Bergas V, de Barros JPP, Narce M, Lobaccaro JMA, Lagrost L, Masson D. Liver X receptor activation promotes polyunsaturated fatty acid synthesis in macrophages: relevance in the context of atherosclerosis. Arterioscler Thromb Vasc Biol 2015; 35:1357-65. [PMID: 25838428 DOI: 10.1161/atvbaha.115.305539] [Citation(s) in RCA: 44] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2014] [Accepted: 03/18/2015] [Indexed: 11/16/2022]
Abstract
OBJECTIVE Liver X receptors (LXRs) modulate cholesterol and fatty acid homeostasis as well as inflammation. This study aims to decipher the role of LXRs in the regulation of polyunsaturated fatty acid (PUFA) synthesis in macrophages in the context of atherosclerosis. APPROACH AND RESULTS Transcriptomic analysis in human monocytes and macrophages was used to identify putative LXR target genes among enzymes involved in PUFA biosynthesis. In parallel, the consequences of LXR activation or LXR invalidation on PUFA synthesis and distribution were determined. Finally, we investigated the impact of LXR activation on PUFA metabolism in vivo in apolipoprotein E-deficient mice. mRNA levels of acyl-CoA synthase long-chain family member 3, fatty acid desaturases 1 and 2, and fatty acid elongase 5 were significantly increased in human macrophages after LXR agonist treatment, involving both direct and sterol responsive element binding protein-1-dependent mechanisms. Subsequently, pharmacological LXR agonist increased long chain PUFA synthesis and enhanced arachidonic acid content in the phospholipids of human macrophages. Increased fatty acid desaturases 1 and 2 and acyl-CoA synthase long-chain family member 3 mRNA levels as well as increased arachidonic acid to linoleic acid and docosahexaenoic acid to eicosapentaenoic acid ratios were also found in atheroma plaque and peritoneal foam cells from LXR agonist-treated mice. By contrast, murine LXR-deficient macrophages displayed reduced expression of fatty acid elongase 5, acyl-CoA synthase long-chain family member 3 and fatty acid desaturases 1, as well as decreased cellular levels of docosahexaenoic acid and arachidonic acid. CONCLUSIONS Our results indicate that LXR activation triggers PUFA synthesis in macrophages, which results in significant alterations in the macrophage lipid composition. Moreover, we demonstrate here that LXR agonist treatment modulates PUFA metabolism in atherosclerotic arteries.
Collapse
Affiliation(s)
- Alexis Varin
- From the Centre de Recherche INSERM-UMR866, Université de Bourgogne, Dijon, France (A.V., C.T., M.I., L.M., T.G., V.B., J.P.P.d.B., M.N., L.L., D.M.); Centre Hospitalier Universitaire Dijon, Dijon, France (L.M., L.L., D.M.); Clermont Université, Université Blaise Pascal (A.T., J.M.A.L.) and Inserm, UMR 1103 (A.T., J.M.A.L.), GReD, Aubière, France; Centre de Recherche en Nutrition Humaine d'Auvergne, Clermont-Ferrand, France (A.T., J.M.A.L.); and Centre National de la Recherche Scientifique, Unité Mixte de Recherche (UMR) 6293, Aubière, France (A.T., J.M.A.L.)
| | - Charles Thomas
- From the Centre de Recherche INSERM-UMR866, Université de Bourgogne, Dijon, France (A.V., C.T., M.I., L.M., T.G., V.B., J.P.P.d.B., M.N., L.L., D.M.); Centre Hospitalier Universitaire Dijon, Dijon, France (L.M., L.L., D.M.); Clermont Université, Université Blaise Pascal (A.T., J.M.A.L.) and Inserm, UMR 1103 (A.T., J.M.A.L.), GReD, Aubière, France; Centre de Recherche en Nutrition Humaine d'Auvergne, Clermont-Ferrand, France (A.T., J.M.A.L.); and Centre National de la Recherche Scientifique, Unité Mixte de Recherche (UMR) 6293, Aubière, France (A.T., J.M.A.L.)
| | - Minako Ishibashi
- From the Centre de Recherche INSERM-UMR866, Université de Bourgogne, Dijon, France (A.V., C.T., M.I., L.M., T.G., V.B., J.P.P.d.B., M.N., L.L., D.M.); Centre Hospitalier Universitaire Dijon, Dijon, France (L.M., L.L., D.M.); Clermont Université, Université Blaise Pascal (A.T., J.M.A.L.) and Inserm, UMR 1103 (A.T., J.M.A.L.), GReD, Aubière, France; Centre de Recherche en Nutrition Humaine d'Auvergne, Clermont-Ferrand, France (A.T., J.M.A.L.); and Centre National de la Recherche Scientifique, Unité Mixte de Recherche (UMR) 6293, Aubière, France (A.T., J.M.A.L.)
| | - Louise Ménégaut
- From the Centre de Recherche INSERM-UMR866, Université de Bourgogne, Dijon, France (A.V., C.T., M.I., L.M., T.G., V.B., J.P.P.d.B., M.N., L.L., D.M.); Centre Hospitalier Universitaire Dijon, Dijon, France (L.M., L.L., D.M.); Clermont Université, Université Blaise Pascal (A.T., J.M.A.L.) and Inserm, UMR 1103 (A.T., J.M.A.L.), GReD, Aubière, France; Centre de Recherche en Nutrition Humaine d'Auvergne, Clermont-Ferrand, France (A.T., J.M.A.L.); and Centre National de la Recherche Scientifique, Unité Mixte de Recherche (UMR) 6293, Aubière, France (A.T., J.M.A.L.)
| | - Thomas Gautier
- From the Centre de Recherche INSERM-UMR866, Université de Bourgogne, Dijon, France (A.V., C.T., M.I., L.M., T.G., V.B., J.P.P.d.B., M.N., L.L., D.M.); Centre Hospitalier Universitaire Dijon, Dijon, France (L.M., L.L., D.M.); Clermont Université, Université Blaise Pascal (A.T., J.M.A.L.) and Inserm, UMR 1103 (A.T., J.M.A.L.), GReD, Aubière, France; Centre de Recherche en Nutrition Humaine d'Auvergne, Clermont-Ferrand, France (A.T., J.M.A.L.); and Centre National de la Recherche Scientifique, Unité Mixte de Recherche (UMR) 6293, Aubière, France (A.T., J.M.A.L.)
| | - Amalia Trousson
- From the Centre de Recherche INSERM-UMR866, Université de Bourgogne, Dijon, France (A.V., C.T., M.I., L.M., T.G., V.B., J.P.P.d.B., M.N., L.L., D.M.); Centre Hospitalier Universitaire Dijon, Dijon, France (L.M., L.L., D.M.); Clermont Université, Université Blaise Pascal (A.T., J.M.A.L.) and Inserm, UMR 1103 (A.T., J.M.A.L.), GReD, Aubière, France; Centre de Recherche en Nutrition Humaine d'Auvergne, Clermont-Ferrand, France (A.T., J.M.A.L.); and Centre National de la Recherche Scientifique, Unité Mixte de Recherche (UMR) 6293, Aubière, France (A.T., J.M.A.L.)
| | - Victoria Bergas
- From the Centre de Recherche INSERM-UMR866, Université de Bourgogne, Dijon, France (A.V., C.T., M.I., L.M., T.G., V.B., J.P.P.d.B., M.N., L.L., D.M.); Centre Hospitalier Universitaire Dijon, Dijon, France (L.M., L.L., D.M.); Clermont Université, Université Blaise Pascal (A.T., J.M.A.L.) and Inserm, UMR 1103 (A.T., J.M.A.L.), GReD, Aubière, France; Centre de Recherche en Nutrition Humaine d'Auvergne, Clermont-Ferrand, France (A.T., J.M.A.L.); and Centre National de la Recherche Scientifique, Unité Mixte de Recherche (UMR) 6293, Aubière, France (A.T., J.M.A.L.)
| | - Jean Paul Pais de Barros
- From the Centre de Recherche INSERM-UMR866, Université de Bourgogne, Dijon, France (A.V., C.T., M.I., L.M., T.G., V.B., J.P.P.d.B., M.N., L.L., D.M.); Centre Hospitalier Universitaire Dijon, Dijon, France (L.M., L.L., D.M.); Clermont Université, Université Blaise Pascal (A.T., J.M.A.L.) and Inserm, UMR 1103 (A.T., J.M.A.L.), GReD, Aubière, France; Centre de Recherche en Nutrition Humaine d'Auvergne, Clermont-Ferrand, France (A.T., J.M.A.L.); and Centre National de la Recherche Scientifique, Unité Mixte de Recherche (UMR) 6293, Aubière, France (A.T., J.M.A.L.)
| | - Michel Narce
- From the Centre de Recherche INSERM-UMR866, Université de Bourgogne, Dijon, France (A.V., C.T., M.I., L.M., T.G., V.B., J.P.P.d.B., M.N., L.L., D.M.); Centre Hospitalier Universitaire Dijon, Dijon, France (L.M., L.L., D.M.); Clermont Université, Université Blaise Pascal (A.T., J.M.A.L.) and Inserm, UMR 1103 (A.T., J.M.A.L.), GReD, Aubière, France; Centre de Recherche en Nutrition Humaine d'Auvergne, Clermont-Ferrand, France (A.T., J.M.A.L.); and Centre National de la Recherche Scientifique, Unité Mixte de Recherche (UMR) 6293, Aubière, France (A.T., J.M.A.L.)
| | - Jean Marc A Lobaccaro
- From the Centre de Recherche INSERM-UMR866, Université de Bourgogne, Dijon, France (A.V., C.T., M.I., L.M., T.G., V.B., J.P.P.d.B., M.N., L.L., D.M.); Centre Hospitalier Universitaire Dijon, Dijon, France (L.M., L.L., D.M.); Clermont Université, Université Blaise Pascal (A.T., J.M.A.L.) and Inserm, UMR 1103 (A.T., J.M.A.L.), GReD, Aubière, France; Centre de Recherche en Nutrition Humaine d'Auvergne, Clermont-Ferrand, France (A.T., J.M.A.L.); and Centre National de la Recherche Scientifique, Unité Mixte de Recherche (UMR) 6293, Aubière, France (A.T., J.M.A.L.)
| | - Laurent Lagrost
- From the Centre de Recherche INSERM-UMR866, Université de Bourgogne, Dijon, France (A.V., C.T., M.I., L.M., T.G., V.B., J.P.P.d.B., M.N., L.L., D.M.); Centre Hospitalier Universitaire Dijon, Dijon, France (L.M., L.L., D.M.); Clermont Université, Université Blaise Pascal (A.T., J.M.A.L.) and Inserm, UMR 1103 (A.T., J.M.A.L.), GReD, Aubière, France; Centre de Recherche en Nutrition Humaine d'Auvergne, Clermont-Ferrand, France (A.T., J.M.A.L.); and Centre National de la Recherche Scientifique, Unité Mixte de Recherche (UMR) 6293, Aubière, France (A.T., J.M.A.L.)
| | - David Masson
- From the Centre de Recherche INSERM-UMR866, Université de Bourgogne, Dijon, France (A.V., C.T., M.I., L.M., T.G., V.B., J.P.P.d.B., M.N., L.L., D.M.); Centre Hospitalier Universitaire Dijon, Dijon, France (L.M., L.L., D.M.); Clermont Université, Université Blaise Pascal (A.T., J.M.A.L.) and Inserm, UMR 1103 (A.T., J.M.A.L.), GReD, Aubière, France; Centre de Recherche en Nutrition Humaine d'Auvergne, Clermont-Ferrand, France (A.T., J.M.A.L.); and Centre National de la Recherche Scientifique, Unité Mixte de Recherche (UMR) 6293, Aubière, France (A.T., J.M.A.L.).
| |
Collapse
|
143
|
Abstract
Bile acids are the end products of cholesterol catabolism. Hepatic bile acid synthesis accounts for a major fraction of daily cholesterol turnover in humans. Biliary secretion of bile acids generates bile flow and facilitates hepatobiliary secretion of lipids, lipophilic metabolites, and xenobiotics. In the intestine, bile acids are essential for the absorption, transport, and metabolism of dietary fats and lipid-soluble vitamins. Extensive research in the last 2 decades has unveiled new functions of bile acids as signaling molecules and metabolic integrators. The bile acid-activated nuclear receptors farnesoid X receptor, pregnane X receptor, constitutive androstane receptor, vitamin D receptor, and G protein-coupled bile acid receptor play critical roles in the regulation of lipid, glucose, and energy metabolism, inflammation, and drug metabolism and detoxification. Bile acid synthesis exhibits a strong diurnal rhythm, which is entrained by fasting and refeeding as well as nutrient status and plays an important role for maintaining metabolic homeostasis. Recent research revealed an interaction of liver bile acids and gut microbiota in the regulation of liver metabolism. Circadian disturbance and altered gut microbiota contribute to the pathogenesis of liver diseases, inflammatory bowel diseases, nonalcoholic fatty liver disease, diabetes, and obesity. Bile acids and their derivatives are potential therapeutic agents for treating metabolic diseases of the liver.
Collapse
Affiliation(s)
- Tiangang Li
- Department of Pharmacology, Toxicology and Therapeutics, University of Kansas Medical Center, Kansas City, Kansas (T.L.); and Department of Integrative Medical Sciences, Northeast Ohio Medical University, Rootstown, Ohio (J.Y.L.C.)
| | - John Y L Chiang
- Department of Pharmacology, Toxicology and Therapeutics, University of Kansas Medical Center, Kansas City, Kansas (T.L.); and Department of Integrative Medical Sciences, Northeast Ohio Medical University, Rootstown, Ohio (J.Y.L.C.)
| |
Collapse
|
144
|
Zhang GH, Lu JX, Chen Y, Guo PH, Qiao ZL, Feng RF, Chen SE, Bai JL, Huo SD, Ma ZR. ChREBP and LXRα mediate synergistically lipogenesis induced by glucose in porcine adipocytes. Gene 2015; 565:30-8. [PMID: 25827716 DOI: 10.1016/j.gene.2015.03.057] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2015] [Revised: 03/25/2015] [Accepted: 03/26/2015] [Indexed: 01/04/2023]
Abstract
Glucose is a substrate for fatty acid synthesis, and induces lipogenesis and expressions of lipogenic genes. It was proposed that transcriptional factor ChREBP, LXRα and SREBP-1c are key mediators in lipogenesis induced by glucose, however the underlying mechanism remains unclear in porcine adipocytes. In this study, glucose stimulated lipogenesis and expressions of ChREBP, LXRα, SREBP-1c and lipogenic genes FAS and ACC1 in primary porcine adipocytes. When ChREBP expression was knocked down by RNAi, lipogenesis and FAS and ACC1 expressions decreased significantly, and lipogenesis induced by glucose decreased by 75.6%, whereas neither the basal expressions under glucose-free nor glucose induced expressions of LXRα and SREBP-1c were evidently affected, suggesting that ChREBP was a main mediator of lipogenesis stimulated by glucose. Glucose promoted LXRα gene expression, and activation of LXRα by T0901317 increased SREBP-1c expression and enhanced the stimulation of glucose on lipogenesis, but this stimulatory effect of LXRα depended on glucose. Activated LXRα stimulated lipogenesis and ChREBP mRNA expression, which was much lower than that elevated by glucose, and was markedly lower in ChREBP-silencing than in unperturbed adipocytes. SREBP-1c activation blocked by fatostatin markedly decreased lipogenesis and expressions of FAS and ACC1 induced by glucose. Lipogenesis and lipogenic gene expression stimulated by LXRα activation were attenuated by fatostatin, however there was still a slightly increase in ChREBP-silencing adipocytes. These dates suggested that LXRα could directly or through SREBP-1c mediate the lipogenesis induced by glucose. Together, glucose induced lipogenesis and lipogenic gene expressions directly through ChREBP, and directly through LXRα or via SREBP-1c.
Collapse
Affiliation(s)
- Guo Hua Zhang
- College of Life Science and Engineering, Northwest University for Nationalities, Lanzhou, Gansu 730030, China
| | - Jian Xiong Lu
- College of Life Science and Engineering, Northwest University for Nationalities, Lanzhou, Gansu 730030, China.
| | - Yan Chen
- College of Life Science and Engineering, Northwest University for Nationalities, Lanzhou, Gansu 730030, China
| | - Peng Hui Guo
- College of Life Science and Engineering, Northwest University for Nationalities, Lanzhou, Gansu 730030, China
| | - Zi Lin Qiao
- Gansu Engineering Research Center for Animal Cell, Northwest University for Nationalities, Lanzhou, Gansu 730030, China
| | - Ruo Fei Feng
- Gansu Engineering Research Center for Animal Cell, Northwest University for Nationalities, Lanzhou, Gansu 730030, China
| | - Shi En Chen
- College of Life Science and Engineering, Northwest University for Nationalities, Lanzhou, Gansu 730030, China
| | - Jia Lin Bai
- Gansu Engineering Research Center for Animal Cell, Northwest University for Nationalities, Lanzhou, Gansu 730030, China
| | - Sheng Dong Huo
- College of Life Science and Engineering, Northwest University for Nationalities, Lanzhou, Gansu 730030, China
| | - Zhong Ren Ma
- Gansu Engineering Research Center for Animal Cell, Northwest University for Nationalities, Lanzhou, Gansu 730030, China.
| |
Collapse
|
145
|
Bindesbøll C, Fan Q, Nørgaard RC, MacPherson L, Ruan HB, Wu J, Pedersen TÅ, Steffensen KR, Yang X, Matthews J, Mandrup S, Nebb HI, Grønning-Wang LM. Liver X receptor regulates hepatic nuclear O-GlcNAc signaling and carbohydrate responsive element-binding protein activity. J Lipid Res 2015; 56:771-85. [PMID: 25724563 DOI: 10.1194/jlr.m049130] [Citation(s) in RCA: 41] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
Liver X receptor (LXR)α and LXRβ play key roles in hepatic de novo lipogenesis through their regulation of lipogenic genes, including sterol regulatory element-binding protein (SREBP)-1c and carbohydrate responsive element-binding protein (ChREBP). LXRs activate lipogenic gene transcription in response to feeding, which is believed to be mediated by insulin. We have previously shown that LXRs are targets for glucose-hexosamine-derived O-linked β-N-acetylglucosamine (O-GlcNAc) modification enhancing their ability to regulate SREBP-1c promoter activity in vitro. To elucidate insulin-independent effects of feeding on LXR-mediated lipogenic gene expression in vivo, we subjected control and streptozotocin-treated LXRα/β(+/+) and LXRα/β(-/-) mice to a fasting-refeeding regime. We show that under hyperglycemic and hypoinsulinemic conditions, LXRs maintain their ability to upregulate the expression of glycolytic and lipogenic enzymes, including glucokinase (GK), SREBP-1c, ChREBPα, and the newly identified shorter isoform ChREBPβ. Furthermore, glucose-dependent increases in LXR/retinoid X receptor-regulated luciferase activity driven by the ChREBPα promoter was mediated, at least in part, by O-GlcNAc transferase (OGT) signaling in Huh7 cells. Moreover, we show that LXR and OGT interact and colocalize in the nucleus and that loss of LXRs profoundly reduced nuclear O-GlcNAc signaling and ChREBPα promoter binding activity in vivo. In summary, our study provides evidence that LXRs act as nutrient and glucose metabolic sensors upstream of ChREBP by modulating GK expression, nuclear O-GlcNAc signaling, and ChREBP expression and activity.
Collapse
Affiliation(s)
- Christian Bindesbøll
- Department of Nutrition, Institute of Basic Medical Sciences, University of Oslo, N-0316 Oslo, Norway
| | - Qiong Fan
- Department of Nutrition, Institute of Basic Medical Sciences, University of Oslo, N-0316 Oslo, Norway
| | - Rikke C Nørgaard
- Department of Nutrition, Institute of Basic Medical Sciences, University of Oslo, N-0316 Oslo, Norway
| | - Laura MacPherson
- Department of Pharmacology and Toxicology, University of Toronto, Toronto, Ontario M5S1A8, Canada
| | - Hai-Bin Ruan
- Program in Integrative Cell Signaling and Neurobiology of Metabolism, Yale University School of Medicine, New Haven, CT 06519 Section of Comparative Medicine, Yale University School of Medicine, New Haven, CT 06519
| | - Jing Wu
- Program in Integrative Cell Signaling and Neurobiology of Metabolism, Yale University School of Medicine, New Haven, CT 06519 Section of Comparative Medicine, Yale University School of Medicine, New Haven, CT 06519
| | - Thomas Å Pedersen
- Department of Biochemistry and Molecular Biology, University of Southern Denmark, 5230 Odense M, Denmark
| | - Knut R Steffensen
- Division of Clinical Chemistry Department of Laboratory Medicine, Karolinska Institutet, Karolinska University Hospital Huddinge, C174, SE-141 86 Stockholm, Sweden
| | - Xiaoyong Yang
- Program in Integrative Cell Signaling and Neurobiology of Metabolism, Yale University School of Medicine, New Haven, CT 06519 Section of Comparative Medicine, Yale University School of Medicine, New Haven, CT 06519 Department of Cellular and Molecular Physiology, Yale University School of Medicine, New Haven, CT 06519
| | - Jason Matthews
- Department of Nutrition, Institute of Basic Medical Sciences, University of Oslo, N-0316 Oslo, Norway Department of Pharmacology and Toxicology, University of Toronto, Toronto, Ontario M5S1A8, Canada
| | - Susanne Mandrup
- Department of Biochemistry and Molecular Biology, University of Southern Denmark, 5230 Odense M, Denmark
| | - Hilde I Nebb
- Department of Nutrition, Institute of Basic Medical Sciences, University of Oslo, N-0316 Oslo, Norway
| | - Line M Grønning-Wang
- Department of Nutrition, Institute of Basic Medical Sciences, University of Oslo, N-0316 Oslo, Norway
| |
Collapse
|
146
|
Kim DI, Park MJ, Lim SK, Park JI, Yoon KC, Han HJ, Gustafsson JÅ, Lim JH, Park SH. PRMT3 regulates hepatic lipogenesis through direct interaction with LXRα. Diabetes 2015; 64:60-71. [PMID: 25187371 DOI: 10.2337/db13-1394] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
Arginine methylation is responsible for diverse biological functions and is mediated by protein arginine methyltransferases (PRMTs). Nonalcoholic fatty liver disease (NAFLD) is accompanied by excessive hepatic lipogenesis via liver X receptor α (LXRα). Thus we examined the pathophysiological role of PRMTs in NAFLD and their relationship with LXRα. In this study, palmitic acid (PA) treatment increased PRMT3, which is correlated with the elevation of hepatic lipogenic proteins. The expression of lipogenic proteins was increased by PRMT3 overexpression, but decreased by PRMT3 silencing and use of the PRMT3 knockout (KO) mouse embryonic fibroblast cell line. PRMT3 also increased the transcriptional activity of LXRα by directly binding with LXRα in a methylation-independent manner. In addition, PA treatment translocated PRMT3 to the nucleus. In animal models, a high-fat diet increased the LXRα and PRMT3 expressions and binding, which was not observed in LXRα KO mice. Furthermore, increased PRMT3 expression and its binding with LXRα were observed in NAFLD patients. Taken together, LXRα and PRMT3 expression was increased in cellular and mouse models of NAFLD and human patients, and PRMT3 translocated into the nucleus bound with LXRα as a transcriptional cofactor, which induced lipogenesis. In conclusion, PRMT3 translocation by PA is coupled to the binding of LXRα, which is responsible for the onset of fatty liver.
Collapse
Affiliation(s)
- Dong-il Kim
- College of Veterinary Medicine, Chonnam National University, Gwangju, Republic of Korea
| | - Min-jung Park
- College of Veterinary Medicine, Chonnam National University, Gwangju, Republic of Korea
| | - Seul-ki Lim
- Metabolism and Functionality Research Group, R&D Division, World Institute of Kimchi, Gwangju, Republic of Korea
| | - Jae-il Park
- Korea Basic Science Institute, Gwangju Center at Chonnam National University, Gwangju, Republic of Korea
| | - Kyung-chul Yoon
- Department of Ophthalmology, Chonnam National University Medical School and Hospital, Gwangju, Republic of Korea
| | - Ho-jae Han
- Department of Verterinary Physiology, College of Veterinary Medicine, Seoul National University, Seoul, Republic of Korea
| | - Jan-åke Gustafsson
- Molecular Nutrition Unit, Department of Bioscience and Nutrition, Karolinska Institutet, Stockholm, Sweden Center for Nuclear Receptors and Cell Signaling, University of Houston, Houston, TX
| | - Jae-hyang Lim
- Department of Microbiology, Ewha Womans University School of Medicine, Seoul, Republic of Korea
| | - Soo-hyun Park
- College of Veterinary Medicine, Chonnam National University, Gwangju, Republic of Korea
| |
Collapse
|
147
|
Abstract
Danhong injection (DHI), a certificated Chinese medical product made from radix salviae miltiorrhizae and flos carthami, is prescribed to patients with coronary heart disease in China. To investigate if DHI can inhibit atherosclerosis, apolipoprotein E-deficient (Apoe⁻/⁻) or low-density lipoprotein receptor-deficient (Ldlr⁻/⁻) mice on high-fat diet were divided into 2 groups and received daily intraperitoneal injection of saline and DHI, respectively, for 16 or 20 weeks. After the treatment, mouse aortas were collected to determine lesions, expression of adenosine triphosphate-binding cassette transporter A1 and tumor necrosis factor-α (TNF-α), and macrophage accumulation. Additionally, serum lipid profiles and expression of hepatic HMG-CoA reductase messenger RNA and low-density lipoprotein receptor protein were determined. We observed that DHI inhibited lesions in both Apoe⁻/⁻ and Ldlr⁻/⁻ mice. Associated with the decreased lesions, the aortic adenosine triphosphate-binding cassette transporter A1 expression was increased, whereas the macrophage accumulation was decreased in male Apoe⁻/⁻ mice and both male and female Ldlr⁻/⁻ mice. Although DHI reduced HMG-CoA reductase messenger RNA expression in both female Apoe⁻/⁻ and Ldlr⁻/⁻ mice, it decreased low-density lipoprotein cholesterol levels only in female Apoe⁻/⁻ mice. In addition to attenuation of lipopolysaccharide-induced expression of TNF-α, IL-1β, IL-6 in macrophages, and human C-reactive protein in hepatocytes, respectively, at the transcriptional level in vitro, DHI also reduced TNF-α protein expression in aortic root of both Apoe⁻/⁻ and Ldlr⁻/⁻ mice, suggesting the importance of the anti-inflammatory properties of DHI in the inhibition of lesion development. Taken together, our study demonstrates that DHI inhibits atherosclerosis in both Apoe⁻/⁻ and Ldlr⁻/⁻ mice with various mechanisms, including anti-inflammation. The inhibition of atherosclerosis can be attributed to the cardioprotective properties of DHI.
Collapse
|
148
|
Haga S, Ozawa T, Yamada Y, Morita N, Nagashima I, Inoue H, Inaba Y, Noda N, Abe R, Umezawa K, Ozaki M. p62/SQSTM1 plays a protective role in oxidative injury of steatotic liver in a mouse hepatectomy model. Antioxid Redox Signal 2014; 21:2515-30. [PMID: 24925527 PMCID: PMC4245881 DOI: 10.1089/ars.2013.5391] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
Abstract
AIMS Liver injury and regeneration involve complicated processes and are affected by various physio-pathological factors. We investigated the mechanisms of steatosis-associated liver injury and delayed regeneration in a mouse model of partial hepatectomy. RESULTS Initial regeneration of the steatotic liver was significantly delayed after hepatectomy. Although hepatocyte proliferation was not significantly suppressed, severe liver injury with oxidative stress (OS) occurred immediately after hepatectomy in the steatotic liver. Fas-ligand (FasL)/Fas expression was upregulated in the steatotic liver, whereas the expression of antioxidant and anti-apoptotic molecules (catalase/MnSOD/Ref-1 and Bcl-2/Bcl-xL/FLIP, respectively) and p62/SQSTM1, a steatosis-associated protein, was downregulated. Interestingly, pro-survival Akt was not activated in response to hepatectomy, although it was sufficiently expressed even before hepatectomy. Suppression of p62/SQSTM1 increased FasL/Fas expression and reduced nuclear factor erythroid 2-related factor-2 (Nrf-2)-dependent antioxidant response elements activity and antioxidant responses in steatotic and nonsteatotic hepatocytes. Exogenously added FasL induced severe cellular OS and necrosis/apoptosis in steatotic hepatocytes, with only the necrosis being inhibited by pretreatment with antioxidants, suggesting that FasL/Fas-induced OS mainly leads to necrosis. Furthermore, p62/SQSTM1 re-expression in the steatotic liver markedly reduced liver injury and improved liver regeneration. INNOVATION This study is the first which demonstrates that reduced expression of p62/SQSTM1 plays a crucial role in posthepatectomy acute injury and delayed regeneration of steatotic liver, mainly via redox-dependent mechanisms. CONCLUSION In the steatotic liver, reduced expression of p62/SQSTM1 induced FasL/Fas overexpression and suppressed antioxidant genes, mainly through Nrf-2 inactivation, which, along with the hypo-responsiveness of Akt, caused posthepatectomy necrotic/apoptotic liver injury and delayed regeneration, both mainly via a redox-dependent mechanism.
Collapse
Affiliation(s)
- Sanae Haga
- 1 Laboratory of Molecular and Functional Bio-imaging, Faculty of Health Sciences, Hokkaido University , Sapporo, Japan
| | | | | | | | | | | | | | | | | | | | | |
Collapse
|
149
|
Abstract
The liver is an essential metabolic organ, and its metabolic function is controlled by insulin and other metabolic hormones. Glucose is converted into pyruvate through glycolysis in the cytoplasm, and pyruvate is subsequently oxidized in the mitochondria to generate ATP through the TCA cycle and oxidative phosphorylation. In the fed state, glycolytic products are used to synthesize fatty acids through de novo lipogenesis. Long-chain fatty acids are incorporated into triacylglycerol, phospholipids, and/or cholesterol esters in hepatocytes. These complex lipids are stored in lipid droplets and membrane structures, or secreted into the circulation as very low-density lipoprotein particles. In the fasted state, the liver secretes glucose through both glycogenolysis and gluconeogenesis. During pronged fasting, hepatic gluconeogenesis is the primary source for endogenous glucose production. Fasting also promotes lipolysis in adipose tissue, resulting in release of nonesterified fatty acids which are converted into ketone bodies in hepatic mitochondria though β-oxidation and ketogenesis. Ketone bodies provide a metabolic fuel for extrahepatic tissues. Liver energy metabolism is tightly regulated by neuronal and hormonal signals. The sympathetic system stimulates, whereas the parasympathetic system suppresses, hepatic gluconeogenesis. Insulin stimulates glycolysis and lipogenesis but suppresses gluconeogenesis, and glucagon counteracts insulin action. Numerous transcription factors and coactivators, including CREB, FOXO1, ChREBP, SREBP, PGC-1α, and CRTC2, control the expression of the enzymes which catalyze key steps of metabolic pathways, thus controlling liver energy metabolism. Aberrant energy metabolism in the liver promotes insulin resistance, diabetes, and nonalcoholic fatty liver diseases.
Collapse
Affiliation(s)
- Liangyou Rui
- Department of Molecular and Integrative Physiology, University of Michigan Medical School, Ann Arbor, Michigan
| |
Collapse
|
150
|
Abstract
NCoR1 (nuclear receptor corepressor) and SMRT (silencing mediator of retinoid and thyroid hormone receptors; NCoR2) are well-recognized coregulators of nuclear receptor (NR) action. However, their unique roles in the regulation of thyroid hormone (TH) signaling in specific cell types have not been determined. To accomplish this we generated mice that lacked function of either NCoR1, SMRT, or both in the liver only and additionally a global SMRT knockout model. Despite both corepressors being present in the liver, deletion of SMRT in either euthyroid or hypothyroid animals had little effect on TH signaling. In contrast, disruption of NCoR1 action confirmed that NCoR1 is the principal mediator of TH sensitivity in vivo. Similarly, global disruption of SMRT, unlike the global disruption of NCoR1, did not affect TH levels. While SMRT played little role in TH-regulated pathways, when disrupted in combination with NCoR1, it greatly accentuated the synthesis and storage of hepatic lipid. Taken together, these data demonstrate that corepressor specificity exists in vivo and that NCoR1 is the principal regulator of TH action. However, both corepressors collaborate to control hepatic lipid content, which likely reflects their cooperative activity in regulating the action of multiple NRs including the TH receptor (TR).
Collapse
|