1
|
Pramfalk C, Ahmed O, Pedrelli M, Minniti ME, Luquet S, Denis RG, Olin M, Härdfeldt J, Vedin LL, Steffensen KR, Rydén M, Hodson L, Eriksson M, Parini P. Soat2 ties cholesterol metabolism to β-oxidation and glucose tolerance in male mice. J Intern Med 2022; 292:296-307. [PMID: 34982494 DOI: 10.1111/joim.13450] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
Abstract
BACKGROUND Sterol O-acyltransferase 2 (Soat2) encodes acyl-coenzyme A:cholesterol acyltransferase 2 (ACAT2), which synthesizes cholesteryl esters in hepatocytes and enterocytes fated either to storage or to secretion into nascent triglyceride-rich lipoproteins. OBJECTIVES We aimed to unravel the molecular mechanisms leading to reduced hepatic steatosis when Soat2 is depleted in mice. METHODS Soat2-/- and wild-type mice were fed a high-fat, a high-carbohydrate, or a chow diet, and parameters of lipid and glucose metabolism were assessed. RESULTS Glucose, insulin, homeostatic model assessment for insulin resistance (HOMA-IR), oral glucose tolerance (OGTT), and insulin tolerance tests significantly improved in Soat2-/- mice, irrespective of the dietary regimes (2-way ANOVA). The significant positive correlations between area under the curve (AUC) OGTT (r = 0.66, p < 0.05), serum fasting insulin (r = 0.86, p < 0.05), HOMA-IR (r = 0.86, p < 0.05), Adipo-IR (0.87, p < 0.05), hepatic triglycerides (TGs) (r = 0.89, p < 0.05), very-low-density lipoprotein (VLDL)-TG (r = 0.87, p < 0.05) and the hepatic cholesteryl esters in wild-type mice disappeared in Soat2-/- mice. Genetic depletion of Soat2 also increased whole-body oxidation by 30% (p < 0.05) compared to wild-type mice. CONCLUSION Our data demonstrate that ACAT2-generated cholesteryl esters negatively affect the metabolic control by retaining TG in the liver and that genetic inhibition of Soat2 improves liver steatosis via partitioning of lipids into secretory (VLDL-TG) and oxidative (fatty acids) pathways.
Collapse
Affiliation(s)
- Camilla Pramfalk
- Cardio Metabolic Unit, Department of Medicine and Department of Laboratory Medicine, Karolinska Institutet, Stockholm, Sweden
- Medicine Unit Endocrinology, Theme Inflammation and Ageing, Karolinska University Hospital, Stockholm, Sweden
| | - Osman Ahmed
- Cardio Metabolic Unit, Department of Medicine and Department of Laboratory Medicine, Karolinska Institutet, Stockholm, Sweden
- Department of Biochemistry, Faculty of Medicine, Khartoum University, Khartoum, Sudan
| | - Matteo Pedrelli
- Cardio Metabolic Unit, Department of Medicine and Department of Laboratory Medicine, Karolinska Institutet, Stockholm, Sweden
| | - Mirko E Minniti
- Cardio Metabolic Unit, Department of Medicine and Department of Laboratory Medicine, Karolinska Institutet, Stockholm, Sweden
| | | | | | - Maria Olin
- Cardio Metabolic Unit, Department of Medicine and Department of Laboratory Medicine, Karolinska Institutet, Stockholm, Sweden
| | - Jennifer Härdfeldt
- Cardio Metabolic Unit, Department of Medicine and Department of Laboratory Medicine, Karolinska Institutet, Stockholm, Sweden
| | - Lise-Lotte Vedin
- Cardio Metabolic Unit, Department of Medicine and Department of Laboratory Medicine, Karolinska Institutet, Stockholm, Sweden
| | - Knut R Steffensen
- Cardio Metabolic Unit, Department of Medicine and Department of Laboratory Medicine, Karolinska Institutet, Stockholm, Sweden
| | - Mikael Rydén
- Medicine Unit Endocrinology, Theme Inflammation and Ageing, Karolinska University Hospital, Stockholm, Sweden
- Unit of Endocrinology, Department of Medicine, Karolinska Institutet at Karolinska University Hospital Huddinge, Stockholm, Sweden
| | - Leanne Hodson
- Oxford Centre for Diabetes, Endocrinology and Metabolism, Radcliffe Department of Medicine, University of Oxford, Oxford, UK
- National Institute for Health Research Oxford Biomedical Research Centre, Oxford University Hospital Trusts, Oxford, UK
| | - Mats Eriksson
- Medicine Unit Endocrinology, Theme Inflammation and Ageing, Karolinska University Hospital, Stockholm, Sweden
- Unit of Endocrinology, Department of Medicine, Karolinska Institutet at Karolinska University Hospital Huddinge, Stockholm, Sweden
| | - Paolo Parini
- Cardio Metabolic Unit, Department of Medicine and Department of Laboratory Medicine, Karolinska Institutet, Stockholm, Sweden
- Medicine Unit Endocrinology, Theme Inflammation and Ageing, Karolinska University Hospital, Stockholm, Sweden
| |
Collapse
|
2
|
Lipid Metabolism Disorders in the Comorbid Course of Nonalcoholic Fatty Liver Disease and Chronic Obstructive Pulmonary Disease. Cells 2021; 10:cells10112978. [PMID: 34831201 PMCID: PMC8616072 DOI: 10.3390/cells10112978] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2021] [Revised: 10/25/2021] [Accepted: 10/30/2021] [Indexed: 02/06/2023] Open
Abstract
Non-alcoholic fatty liver disease (NAFLD) is currently among the most common liver diseases. Unfavorable data on the epidemiology of metabolic syndrome and obesity have increased the attention of clinicians and researchers to the problem of NAFLD. The research results allow us to emphasize the systemicity and multifactoriality of the pathogenesis of liver parenchyma lesion. At the same time, many aspects of its classification, etiology, and pathogenesis remain controversial. Local and systemic metabolic disorders are also a part of the pathogenesis of chronic obstructive pulmonary disease and can influence its course. The present article analyzes the metabolic pathways mediating the links of impaired lipid metabolism in NAFLD and chronic obstructive pulmonary disease (COPD). Free fatty acids, cholesterol, and ceramides are involved in key metabolic and inflammatory pathways underlying the pathogenesis of both diseases. Moreover, inflammation and lipid metabolism demonstrate close links in the comorbid course of NAFLD and COPD.
Collapse
|
3
|
Dixon ED, Nardo AD, Claudel T, Trauner M. The Role of Lipid Sensing Nuclear Receptors (PPARs and LXR) and Metabolic Lipases in Obesity, Diabetes and NAFLD. Genes (Basel) 2021; 12:genes12050645. [PMID: 33926085 PMCID: PMC8145571 DOI: 10.3390/genes12050645] [Citation(s) in RCA: 39] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2021] [Revised: 04/23/2021] [Accepted: 04/23/2021] [Indexed: 12/11/2022] Open
Abstract
Obesity and type 2 diabetes mellitus (T2DM) are metabolic disorders characterized by metabolic inflexibility with multiple pathological organ manifestations, including non-alcoholic fatty liver disease (NAFLD). Nuclear receptors are ligand-dependent transcription factors with a multifaceted role in controlling many metabolic activities, such as regulation of genes involved in lipid and glucose metabolism and modulation of inflammatory genes. The activity of nuclear receptors is key in maintaining metabolic flexibility. Their activity depends on the availability of endogenous ligands, like fatty acids or oxysterols, and their derivatives produced by the catabolic action of metabolic lipases, most of which are under the control of nuclear receptors. For example, adipose triglyceride lipase (ATGL) is activated by peroxisome proliferator-activated receptor γ (PPARγ) and conversely releases fatty acids as ligands for PPARα, therefore, demonstrating the interdependency of nuclear receptors and lipases. The diverse biological functions and importance of nuclear receptors in metabolic syndrome and NAFLD has led to substantial effort to target them therapeutically. This review summarizes recent findings on the roles of lipases and selected nuclear receptors, PPARs, and liver X receptor (LXR) in obesity, diabetes, and NAFLD.
Collapse
Affiliation(s)
| | | | | | - Michael Trauner
- Correspondence: ; Tel.: +43-140-4004-7410; Fax: +43-14-0400-4735
| |
Collapse
|
4
|
González-Granillo M, Savva C, Li X, Ghosh Laskar M, Angelin B, Gustafsson JÅ, Korach-André M. Selective estrogen receptor (ER)β activation provokes a redistribution of fat mass and modifies hepatic triglyceride composition in obese male mice. Mol Cell Endocrinol 2020; 502:110672. [PMID: 31811898 DOI: 10.1016/j.mce.2019.110672] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/23/2019] [Revised: 11/25/2019] [Accepted: 11/30/2019] [Indexed: 02/07/2023]
Abstract
Estrogen exerts its action through the binding to two major receptors, estrogen receptor (ER)α and β. Recently, the beneficial role of selective ERβ activation in the regulation of metabolic homeostasis in obesity has been demonstrated, but its importance is still controversial. However, no data are available regarding possible gender differences in response to pharmaceutical activation of ERβ. Male mice were fed a control diet (CD) or a high fat diet (HFD) before being treated with the ERβ selective ligand, 4-(2-(3-5-dimethylisoxazol-4-yl)-1H-indol-3yl)phenol (DIP) in the same conditions as in our recently published paper in female mice. Magnetic resonance imaging and spectroscopy were performed repeatedly in vivo after 6 weeks of diet and after 2 weeks of DIP. Adipose tissue distribution and hepatic triglycerides composition were quantified. HFD-treated males showed a feminization of their fat distribution towards more subcutaneous fat depots and increase total fat content and visceral adipose tissue showed clear browning sites after DIP. Hepatic lipid composition was modified by DIP, with less saturated and more unsaturated lipids and an improved insulin sensitivity. Finally, brown adipose tissue size expended after DIP, due to an increase of the size of the lipid droplets. Our data demonstrate that selective activation of ERβ exerts a tissue-specific and sex-dependent response to metabolic adaptation to overfeeding. Most importantly, together with our previously published results in females, the current findings support the concept that sex should be considered in the future development of obesity-moderating drugs.
Collapse
Affiliation(s)
- Marcela González-Granillo
- Department of Medicine, Metabolism Unit, KI/AZ Integrated Cardio Metabolic Center (ICMC), Karolinska Institutet at Karolinska University Hospital Huddinge, Stockholm, Sweden; Clinical Department of Endocrinology, Metabolism and Diabetes, Karolinska University Hospital Huddinge, Stockholm, Sweden
| | - Christina Savva
- Department of Medicine, Metabolism Unit, KI/AZ Integrated Cardio Metabolic Center (ICMC), Karolinska Institutet at Karolinska University Hospital Huddinge, Stockholm, Sweden; Clinical Department of Endocrinology, Metabolism and Diabetes, Karolinska University Hospital Huddinge, Stockholm, Sweden
| | - Xidan Li
- Department of Medicine, Metabolism Unit, KI/AZ Integrated Cardio Metabolic Center (ICMC), Karolinska Institutet at Karolinska University Hospital Huddinge, Stockholm, Sweden
| | - Moumita Ghosh Laskar
- Clinical Department of Endocrinology, Metabolism and Diabetes, Karolinska University Hospital Huddinge, Stockholm, Sweden
| | - Bo Angelin
- Department of Medicine, Metabolism Unit, KI/AZ Integrated Cardio Metabolic Center (ICMC), Karolinska Institutet at Karolinska University Hospital Huddinge, Stockholm, Sweden; Clinical Department of Endocrinology, Metabolism and Diabetes, Karolinska University Hospital Huddinge, Stockholm, Sweden
| | - Jan-Åke Gustafsson
- Department of Biology and Biochemistry, Center for Nuclear Receptors and Cell Signalling, University of Houston, Houston, TX, USA; Department of Biosciences and Nutrition Huddinge, Karolinska Institutet, Sweden
| | - Marion Korach-André
- Department of Medicine, Metabolism Unit, KI/AZ Integrated Cardio Metabolic Center (ICMC), Karolinska Institutet at Karolinska University Hospital Huddinge, Stockholm, Sweden; Clinical Department of Endocrinology, Metabolism and Diabetes, Karolinska University Hospital Huddinge, Stockholm, Sweden.
| |
Collapse
|
5
|
Sun T, Gao J, Han D, Shi H, Liu X. Fabrication and characterization of solid lipid nano-formulation of astraxanthin against DMBA-induced breast cancer via Nrf-2-Keap1 and NF-kB and mTOR/Maf-1/PTEN pathway. Drug Deliv 2019; 26:975-988. [PMID: 31556759 PMCID: PMC6781204 DOI: 10.1080/10717544.2019.1667454] [Citation(s) in RCA: 25] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2019] [Accepted: 09/10/2019] [Indexed: 12/12/2022] Open
Abstract
In the current experimental study, we scrutinized the chemoprotective effect of astraxanthin against the 7,12-dimethylbenz(a)anthracene (DMBA)-induced breast cancer via Nrf-2-Keap1 and NF-kB and mTOR/Maf-1/PTEN pathway. The double emulsion solvent displacement method was used for the preparation of astraxanthin solid lipid nanoparticles (SLN). SLNs were appraised for entrapment, potential, size, drug-release performance, and gastric stability. DMBA (8 mg/kg) was used for the induction of breast cancer. Tumor weight, body weight, and tumor incidence were estimated at a regular interval. Different biochemical parameters such as Na+/K+, Ca2+, and Mg2+ activity, antioxidant, lipid, glycoprotein, phase I and II biotransformation enzymes, mitochondrial TCA cycle, and carbohydrate metabolizing enzymes were estimated. Keap1-Nrf-2, associated HO-1, and NF-kB expressions were estimated. Moreover, it estimated the mRNA expression of LXR (α,β), HMG-CoAR, PTEN, Maf1, PI3K, mTOR, Akt, FASN, and ACC1. AX-SLN reduced the tumor incidence, tumor weight, and increased the body weight. AX-SLN exhibited the protective effect against the LPO, enzymic (SOD, CuZnSOD, MnSOD, GPx, and CAT), and nonenzymic (GSH) in the serum, mammary gland, renal, and hepatic tissues. AX-SLN reduced the p-AKT which is accountable for the reduction in the NF-kB expression and also reduced the expression of Keap1 and NF-kB along with increasing the expression of HO-1 and Nrf-2. Further, AX-SLN significantly altered the mRNA of LXR (α,β), HMG-CoAR, PTEN, Maf1, PI3K, mTOR, Akt, FASN, and ACC1. On the basis of the results, we can conclude that AX-SLN inhibits the mammary gland carcinogenesis via Nrf-2-Keap1, NF-kB, and mTOR/Maf-1/PTEN pathway.
Collapse
Affiliation(s)
- Tao Sun
- Department of Thyroid Breast Surgery, Jinan Central Hospital Affiliated to Shandong University, Jinan, China
| | - Jun Gao
- Department of Thyroid Breast Surgery, Jinan Central Hospital Affiliated to Shandong University, Jinan, China
| | - Dan Han
- Eye, Plastic and Oral Wards, Jinan Central Hospital Affiliated to Shandong University, Jinan, China
| | - Hongyan Shi
- Department of ENT (Ear–Nose–Throat), Jinan Central Hospital Affiliated to Shandong University, Jinan, China
| | - Xianqiang Liu
- Department of Thyroid Breast Surgery, Jinan Central Hospital Affiliated to Shandong University, Jinan, China
| |
Collapse
|
6
|
González-Granillo M, Savva C, Li X, Fitch M, Pedrelli M, Hellerstein M, Parini P, Korach-André M, Gustafsson JÅ. ERβ activation in obesity improves whole body metabolism via adipose tissue function and enhanced mitochondria biogenesis. Mol Cell Endocrinol 2019; 479:147-158. [PMID: 30342056 DOI: 10.1016/j.mce.2018.10.007] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/07/2018] [Revised: 08/13/2018] [Accepted: 10/07/2018] [Indexed: 12/17/2022]
Abstract
OBJECTIVE Estrogens play a key role in the distribution of adipose tissue and have their action by binding to both estrogen receptors (ER), α and β. Although ERβ has a role in the energy metabolism, limited data of the physiological mechanism and metabolic response involved in the pharmacological activation of ERβ is available. METHODS For clinical relevance, non-ovariectomized female mice were subjected to high fat diet together with pharmacological (DIP - 4-(2-(3,5-dimethylisoxazol-4-yl)-1H-indol-3-yl)phenol) interventions to ERβ selective activation. The physiological mechanism was assessed in vivo by magnetic resonance imaging and spectroscopy, and oral glucose and intraperitoneal insulin tolerance test before and after DIP treatment. Liver and adipose tissue metabolic response was measured in HFD + vehicle and HFD + DIP by stable isotope, RNA sequencing and protein content. RESULTS HFD-fed females treated with DIP had a tissue-specific response towards ERβ selective activation. The metabolic profile showed an improved fasting glucose level, insulin sensitivity and reduced liver steatosis. CONCLUSIONS Our data demonstrate that selective activation of ERβ exerts a tissue-specific activity which promotes a beneficial effect on whole body metabolic response to obesity.
Collapse
Affiliation(s)
- Marcela González-Granillo
- Department of Medicine, Metabolism Unit and KI/AZ Integrated CardioMetabolic Center (ICMC), Karolinska Institutet at Karolinska University Hospital Huddinge, Stockholm, Sweden; Department of Biosciences and Nutrition Huddinge, Karolinska Institutet, Sweden.
| | - Christina Savva
- Department of Medicine, Metabolism Unit and KI/AZ Integrated CardioMetabolic Center (ICMC), Karolinska Institutet at Karolinska University Hospital Huddinge, Stockholm, Sweden; Department of Biosciences and Nutrition Huddinge, Karolinska Institutet, Sweden
| | - Xidan Li
- Department of Medicine, Metabolism Unit and KI/AZ Integrated CardioMetabolic Center (ICMC), Karolinska Institutet at Karolinska University Hospital Huddinge, Stockholm, Sweden
| | - Mark Fitch
- Department of Nutritional Sciences & Toxicology, University of California, Berkeley, USA
| | - Matteo Pedrelli
- Division of Clinical Chemistry, Department of Laboratory Medicine, Karolinska Institutet, Sweden
| | - Marc Hellerstein
- Department of Nutritional Sciences & Toxicology, University of California, Berkeley, USA
| | - Paolo Parini
- Department of Medicine and Department of Laboratory Medicine, Karolinska Institutet, Sweden
| | - Marion Korach-André
- Department of Medicine, Metabolism Unit and KI/AZ Integrated CardioMetabolic Center (ICMC), Karolinska Institutet at Karolinska University Hospital Huddinge, Stockholm, Sweden; Department of Biosciences and Nutrition Huddinge, Karolinska Institutet, Sweden.
| | - Jan-Åke Gustafsson
- Department of Biosciences and Nutrition Huddinge, Karolinska Institutet, Sweden; Department of Biology and Biochemistry, Center for Nuclear Receptors and Cell Signalling, University of Houston, Houston, TX, USA
| |
Collapse
|
7
|
Transcriptional control of intestinal cholesterol absorption, adipose energy expenditure and lipid handling by Sortilin. Sci Rep 2018; 8:9006. [PMID: 29899496 PMCID: PMC5998044 DOI: 10.1038/s41598-018-27416-y] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2018] [Accepted: 05/31/2018] [Indexed: 12/11/2022] Open
Abstract
The sorting receptor Sortilin functions in the regulation of glucose and lipid metabolism. Dysfunctional lipid uptake, storage, and metabolism contribute to several major human diseases including atherosclerosis and obesity. Sortilin associates with cardiovascular disease; however, the role of Sortilin in adipose tissue and lipid metabolism remains unclear. Here we show that in the low-density lipoprotein receptor-deficient (Ldlr−/−) atherosclerosis model, Sortilin deficiency (Sort1−/−) in female mice suppresses Niemann-Pick type C1-Like 1 (Npc1l1) mRNA levels, reduces body and white adipose tissue weight, and improves brown adipose tissue function partially via transcriptional downregulation of Krüppel-like factor 4 and Liver X receptor. Female Ldlr−/−Sort1−/− mice on a high-fat/cholesterol diet had elevated plasma Fibroblast growth factor 21 and Adiponectin, an adipokine that when reduced is associated with obesity and cardiovascular disease-related factors. Additionally, Sort1 deficiency suppressed cholesterol absorption in both female mice ex vivo intestinal tissue and human colon Caco-2 cells in a similar manner to treatment with the NPC1L1 inhibitor ezetimibe. Together our findings support a novel role of Sortilin in energy regulation and lipid homeostasis in female mice, which may be a potential therapeutic target for obesity and cardiovascular disease.
Collapse
|
8
|
Fornes R, Maliqueo M, Hu M, Hadi L, Jimenez-Andrade JM, Ebefors K, Nyström J, Labrie F, Jansson T, Benrick A, Stener-Victorin E. The effect of androgen excess on maternal metabolism, placental function and fetal growth in obese dams. Sci Rep 2017; 7:8066. [PMID: 28808352 PMCID: PMC5556034 DOI: 10.1038/s41598-017-08559-w] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2017] [Accepted: 07/11/2017] [Indexed: 12/11/2022] Open
Abstract
Pregnant women with polycystic ovary syndrome (PCOS) are often overweight or obese. To study the effects of maternal androgen excess in obese dams on metabolism, placental function and fetal growth, female C57Bl6J mice were fed a control (CD) or a high fat/high sucrose (HF/HS) diet for 4-10 weeks, and then mated. On gestational day (GD) 15.5-17.5, dams were injected with dihydrotestosterone (CD-DHT, HF/HS-DHT) or a vehicle (CD-Veh, HF/HS-Veh). HF/HS dams had higher fat content, both before mating and on GD18.5, with no difference in glucose homeostasis, whereas the insulin sensitivity was higher in DHT-exposed dams. Compared to the CD groups, the livers from HF/HS dams weighed more on GD18.5, the triglyceride content was higher, and there was a dysregulation of liver enzymes related to lipogenesis and higher mRNA expression of Fitm1. Fetuses from HF/HS-Veh dams had lower liver triglyceride content and mRNA expression of Srebf1c. Maternal DHT exposure, regardless of diet, decreased fetal liver Pparg mRNA expression and increased placental androgen receptor protein expression. Maternal diet-induced obesity, together with androgen excess, affects maternal and fetal liver function as demonstrated by increased triglyceride content and dysfunctional expression of enzymes and transcription factors involved in de novo lipogenesis and fat storage.
Collapse
Affiliation(s)
- Romina Fornes
- Department of Physiology and Pharmacology, Karolinska Institutet, 171 77, Stockholm, Sweden
| | - Manuel Maliqueo
- Department of Physiology and Pharmacology, Karolinska Institutet, 171 77, Stockholm, Sweden
- Endocrinology and Metabolism Laboratory, Department of Medicine, West Division, University of Chile, Santiago, Chile
| | - Min Hu
- Department of Physiology, Institute of Neuroscience and Physiology, Sahlgrenska Academy, University of Gothenburg, Gothenburg, Sweden
| | - Laila Hadi
- Department of Physiology, Institute of Neuroscience and Physiology, Sahlgrenska Academy, University of Gothenburg, Gothenburg, Sweden
| | - Juan M Jimenez-Andrade
- Unidad Académica Multidisciplinaria Reynosa Aztlán, Universidad Autónoma de Tamaulipas, Reynosa, Tamaulipas, Mexico
| | - Kerstin Ebefors
- Department of Physiology, Institute of Neuroscience and Physiology, Sahlgrenska Academy, University of Gothenburg, Gothenburg, Sweden
| | - Jenny Nyström
- Department of Physiology, Institute of Neuroscience and Physiology, Sahlgrenska Academy, University of Gothenburg, Gothenburg, Sweden
| | - Fernand Labrie
- Laval University Research Center in Molecular Endocrinology, Oncology and Human Genomics, CHUL Research Center, Quebec, G1V 4G2, Canada
| | - Thomas Jansson
- Department of Obstetrics & Gynecology, Division of Reproductive Sciences, University Colorado Anschutz Medical Campus, Aurora, Colorado, 80045, USA
| | - Anna Benrick
- Department of Physiology, Institute of Neuroscience and Physiology, Sahlgrenska Academy, University of Gothenburg, Gothenburg, Sweden
- School of Health and Education, University of Skövde, 54128, Skovde, Sweden
| | | |
Collapse
|
9
|
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
|
10
|
Al-Qahtani SM, Bryzgalova G, Valladolid-Acebes I, Korach-André M, Dahlman-Wright K, Efendić S, Berggren PO, Portwood N. 17β-Estradiol suppresses visceral adipogenesis and activates brown adipose tissue-specific gene expression. Horm Mol Biol Clin Investig 2017; 29:13-26. [PMID: 27831918 DOI: 10.1515/hmbci-2016-0031] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2016] [Accepted: 09/30/2016] [Indexed: 11/15/2022]
Abstract
Both functional ovaries and estrogen replacement therapy (ERT) reduce the risk of type 2 diabetes (T2D). Understanding the mechanisms underlying the antidiabetic effects of 17β-estradiol (E2) may permit the development of a molecular targeting strategy for the treatment of metabolic disease. This study examines how the promotion of insulin sensitivity and weight loss by E2 treatment in high-fat-diet (HFD)-fed mice involve several anti-adipogenic processes in the visceral adipose tissue. Magnetic resonance imaging (MRI) revealed specific reductions in visceral adipose tissue volume in HFD+E2 mice, compared with HFD mice. This loss of adiposity was associated with diminished visceral adipocyte size and reductions in expression of lipogenic genes, adipokines and of the nuclear receptor nr2c2/tr4. Meanwhile, expression levels of adipose triglyceride lipase/pnpla2 and leptin receptor were increased. As mRNA levels of stat3, a transcription factor involved in brown adipose tissue differentiation, were also increased in visceral adipose, the expression of other brown adipose-specific markers was assessed. Both expression and immunohistochemical staining of ucp-1 were increased, and mRNA levels of dio-2, and of adrβ3, a regulator of ucp-1 expression during the thermogenic response, were increased. Furthermore, expression of cpt-1b, a brown adipose-specific gene involved in fatty acid utilization, was also increased. Methylation studies demonstrated that the methylation status of both dio-2 and adrβ3 was significantly reduced. These results show that improved glycemic control and weight loss due to E2 involve anti-adipogenic mechanisms which include suppressed lipogenesis and augmented fatty acid utilization, and in addition, the activation of brown adipose tissue-specific gene expression in association with E2-dependent epigenetic modifications in these genes.
Collapse
|
11
|
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
|
12
|
Li Y, Jing C, Tang X, Chen Y, Han X, Zhu Y. LXR activation causes G1/S arrest through inhibiting SKP2 expression in MIN6 pancreatic beta cells. Endocrine 2016; 53:689-700. [PMID: 27071658 DOI: 10.1007/s12020-016-0915-8] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/20/2015] [Accepted: 03/02/2016] [Indexed: 11/24/2022]
Abstract
Liver X receptors (LXRs) are nuclear hormone receptors with central roles in lipid homeostasis. We previously showed that LXR activation induced aberrant lipid metabolism and G1 cell cycle arrest in pancreatic beta cells. In this study, we aimed to identify the molecular target of LXR causing G1 arrest. LXR activation was induced by its agonist, T0901317. A series of luciferase reporters of truncated Skp2 promoter were analyzed in MIN6 cells. mRNA and protein levels of SKP2 and P27 were detected. Flow cytometry assay was used to determine the cell cycle distribution. MTT assay was used to evaluate cell viability. LXR activation increased cell distribution in G1 phase and lipid accumulation. Since dominant-negative Srebp1c could clear the deposited lipid rather than recover the G1 arrest, we identified S-phase kinase-associated protein 2 (Skp2) as a potential target gene of LXR. In deed, LXR activation significantly inhibited Skp2 gene expression and protein amount. We also observed that the luciferase activity of Skp2 promoter was suppressed by T0901317 and the potential LXR regulatory site was narrowed down to a region of nt -289 to -38. Silencing Lxrα and Lxrβ rescued SKP2 protein level and recovered the cellular growth repressed by LXR activation. Moreover, SKP2 overabundance reduced P27 protein level by promoting its degradation, consequently overcame the G1 arrest caused by T0901317. Our findings demonstrate that transrepressing Skp2 expression by LXR activation resulted in defective SKP2-mediated P27 degradation and inhibitory cell growth in beta cells.
Collapse
Affiliation(s)
- Yating Li
- Key Laboratory of Human Functional Genomics of Jiangsu Province, Department of Biochemistry and Molecular Biology, Nanjing Medical University, 140 Hanzhong Road, Nanjing, 210029, People's Republic of China
| | - Changwen Jing
- Key Laboratory of Human Functional Genomics of Jiangsu Province, Department of Biochemistry and Molecular Biology, Nanjing Medical University, 140 Hanzhong Road, Nanjing, 210029, People's Republic of China
| | - Xinyi Tang
- Key Laboratory of Human Functional Genomics of Jiangsu Province, Department of Biochemistry and Molecular Biology, Nanjing Medical University, 140 Hanzhong Road, Nanjing, 210029, People's Republic of China
| | - Yuanyuan Chen
- Key Laboratory of Human Functional Genomics of Jiangsu Province, Department of Biochemistry and Molecular Biology, Nanjing Medical University, 140 Hanzhong Road, Nanjing, 210029, People's Republic of China
| | - Xiao Han
- Key Laboratory of Human Functional Genomics of Jiangsu Province, Department of Biochemistry and Molecular Biology, Nanjing Medical University, 140 Hanzhong Road, Nanjing, 210029, People's Republic of China
| | - Yunxia Zhu
- Key Laboratory of Human Functional Genomics of Jiangsu Province, Department of Biochemistry and Molecular Biology, Nanjing Medical University, 140 Hanzhong Road, Nanjing, 210029, People's Republic of China.
| |
Collapse
|
13
|
Once and for all, LXRα and LXRβ are gatekeepers of the endocrine system. Mol Aspects Med 2016; 49:31-46. [DOI: 10.1016/j.mam.2016.04.001] [Citation(s) in RCA: 42] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2015] [Revised: 03/08/2016] [Accepted: 04/10/2016] [Indexed: 01/08/2023]
|
14
|
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
|
15
|
Ouadah-Boussouf N, Babin PJ. Pharmacological evaluation of the mechanisms involved in increased adiposity in zebrafish triggered by the environmental contaminant tributyltin. Toxicol Appl Pharmacol 2016; 294:32-42. [PMID: 26812627 DOI: 10.1016/j.taap.2016.01.014] [Citation(s) in RCA: 43] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2015] [Revised: 01/09/2016] [Accepted: 01/09/2016] [Indexed: 01/06/2023]
Abstract
One proposed contributing factor to the rise in overweight and obesity is exposure to endocrine disrupting chemicals. Tributyltin chloride (TBT), an organotin, induces adipogenesis in cell culture models and may increases adipose mass in vivo in vertebrate model organisms. It has been hypothesized that TBT acts via the peroxisome proliferator activated receptor (PPAR)γ-dependent pathway. However, the mechanisms involved in the effects of TBT exposure on in vivo adipose tissue metabolism remain unexplored. Semitransparent zebrafish larvae, with their well-developed white adipose tissue, offer a unique opportunity for studying the effects of toxicant chemicals and pharmaceuticals on adipocyte biology and whole-organism adiposity in a vertebrate model. Within hours, zebrafish larvae, treated at environmentally-relevant nanomolar concentrations of TBT, exhibited a remarkable increase in adiposity linked to adipocyte hypertrophy. Under the experimental conditions used, we also demonstrated that zebrafish larvae adipose tissue proved to be highly responsive to selected human nuclear receptor agonists and antagonists. Retinoid X receptor (RXR) homodimers and RXR/liver X receptor heterodimers were suggested to be in vivo effectors of the obesogenic effect of TBT on zebrafish white adipose tissue. RXR/PPARγ heterodimers may be recruited to modulate adiposity in zebrafish but were not a necessary requirement for the short term in vivo TBT obesogenic effect. Together, the present results suggest that TBT may induce the promotion of triacylglycerol storage in adipocytes via RXR-dependent pathways without necessary using PPAR isoforms.
Collapse
Affiliation(s)
- Nafia Ouadah-Boussouf
- Maladies Rares: Génétique et Métabolisme (MRGM), Univ. Bordeaux, INSERM, U1211, F-33615 Pessac, France
| | - Patrick J Babin
- Maladies Rares: Génétique et Métabolisme (MRGM), Univ. Bordeaux, INSERM, U1211, F-33615 Pessac, France.
| |
Collapse
|
16
|
Huwait EA, Singh NN, Michael DR, Davies TS, Moss JW, Ramji DP. Protein Kinase C Is Involved in the Induction of ATP-Binding Cassette Transporter A1 Expression by Liver X Receptor/Retinoid X Receptor Agonist in Human Macrophages. J Cell Biochem 2015; 116:2032-8. [DOI: 10.1002/jcb.25157] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2014] [Accepted: 03/03/2015] [Indexed: 11/12/2022]
Affiliation(s)
- Etimad A. Huwait
- Cardiff School of Biosciences; Cardiff University; Sir Martin Evans Building Museum Avenue Cardiff CF10 3AX United Kingdom
| | - Nishi N. Singh
- Cardiff School of Biosciences; Cardiff University; Sir Martin Evans Building Museum Avenue Cardiff CF10 3AX United Kingdom
| | - Daryn R. Michael
- Cardiff School of Biosciences; Cardiff University; Sir Martin Evans Building Museum Avenue Cardiff CF10 3AX United Kingdom
| | - Thomas S. Davies
- Cardiff School of Biosciences; Cardiff University; Sir Martin Evans Building Museum Avenue Cardiff CF10 3AX United Kingdom
| | - Joe W.E. Moss
- Cardiff School of Biosciences; Cardiff University; Sir Martin Evans Building Museum Avenue Cardiff CF10 3AX United Kingdom
| | - Dipak P. Ramji
- Cardiff School of Biosciences; Cardiff University; Sir Martin Evans Building Museum Avenue Cardiff CF10 3AX United Kingdom
| |
Collapse
|
17
|
Zadjali F, Santana-Farre R, Mirecki-Garrido M, Ellis E, Norstedt G, Fernandez-Perez L, Flores-Morales A. Liver X receptor agonist downregulates growth hormone signaling in the liver. Horm Mol Biol Clin Investig 2015; 8:471-8. [PMID: 25961345 DOI: 10.1515/hmbci.2011.125] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2011] [Accepted: 11/09/2011] [Indexed: 12/13/2022]
Abstract
Liver X receptor (LXR) agonists have been shown to influence the development of hyperlipidemia and atherosclerosis in mouse models. It has also been demonstrated that some LXR agonists can cause hepatic steatosis in experimental animals. Growth hormone (GH) is known to regulate hepatic metabolism and the absence of hepatic GH receptors (GHR) leads to hepatic steatosis. In this study, we analyzed whether the actions of LXR agonists could involve interference with GH signaling. We showed that LXR agonists impair GH signaling in hepatocytes. LXR agonist treatment attenuated GH induction of suppressor of cytokine signaling 2 (SOCS2), SOCS3, and CIS mRNA levels in BRL-4 cells. Likewise, the activity of a luciferase reporter vector driven by the GH response element (GHRE) of the SOCS2 gene was inhibited by simultaneous treatment with an LXR agonist. The inhibitory effect of LXR agonists on GH signals can be mimicked by overexpression of the LXR regulated factors, sterol regulatory element binding protein 1 (SREBP1) and SREBP2, in hepatic cells. In both cases total and phosphorylated signal transducers and activators of transcription 5b (STAT5b) protein levels were significantly reduced. DNA binding assays demonstrated that SREBP1 binds to an E-box within a previously defined GHRE in the SOCS2 gene promoter, but does not compete with STAT5b binding to a nearby site in the same promoter construct. Taken together, our findings indicate that the inhibitory effects of LXR agonists on GH signaling are mediated by SREBP1, through the downregulation of STAT5b gene transcription and stimulation of STAT5b protein degradation. The findings provide a new insight into the understanding of the molecular actions of LXR agonists, which may be of relevance to their pharmacological actions.
Collapse
|
18
|
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
|
19
|
Kato T, Kawahito H, Kishida S, Irie D, Wakana N, Kikai M, Takata H, Ogata T, Ueyama T, Matoba S, Yamada H. Bone marrow angiotensin AT2 receptor deficiency aggravates atherosclerosis development by eliminating macrophage liver X receptor-mediated anti-atherogenic actions. J Renin Angiotensin Aldosterone Syst 2014; 16:936-46. [PMID: 25487979 DOI: 10.1177/1470320314561138] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
BACKGROUND Bone marrow (BM) Angiotensin II (Ang II) type 1 (AT1) receptor plays a crucial role in atherosclerosis development; however, the effect of BM Ang II type 2 (AT2) receptor on atherogenesis remains undefined. METHODS AND RESULTS We generated BM chimera apoE-deficient (apoE(-/-)) mice whose BM cells were repopulated with AT2-deficient (Agtr2(-/-)) or wild-type (Agtr2(+/+)) cells. After 2 months of a high-cholesterol diet, the atherosclerotic lesion area was significantly increased in the apoE(-/-)/BM-Agtr2(-/-) mice compared with the apoE(-/-)/BM-Agtr2(+/+) mice (51%, P < 0.05), accompanied by an augmented accumulation of lesion macrophages. Although phenotypic polarization in BM-derived macrophages and lipopolysaccharide-induced expression of proinflammatory cytokines in thioglycollate-induced peritoneal macrophages (TGPMs) were not affected by AT2-deficiency, mRNA and protein expression levels of macrophage liver X receptor β (LXRβ) were significantly decreased in Agtr2(-/-) TGPMs compared with Agtr2(+/+) TGPMs. Anti-inflammatory effects of LXR agonist (GW3965) were markedly inhibited in Agtr2(-/-) TGPMs. Furthermore, the expression levels of ATP-binding cassette transporter ABCA1 and CCR7 were much lower in Agtr2(-/-) TGPMs than Agtr2(+/+) TGPMs, accompanied by a significantly reduced cholesterol efflux. CONCLUSIONS Our findings demonstrate that BM-AT2 deficiency aggravates atherosclerosis, at least in part, by eliminating the anti-atherogenic properties of macrophages elicited by LXRβ activation.
Collapse
Affiliation(s)
- Taku Kato
- Department of Cardiovascular Medicine, Kyoto Prefectural University of Medicine, Japan
| | - Hiroyuki Kawahito
- Department of Cardiovascular Medicine, Kyoto Prefectural University of Medicine, Japan
| | - Sou Kishida
- Department of Cardiovascular Medicine, Kyoto Prefectural University of Medicine, Japan
| | - Daisuke Irie
- Department of Cardiovascular Medicine, Kyoto Prefectural University of Medicine, Japan
| | - Noriyuki Wakana
- Department of Cardiovascular Medicine, Kyoto Prefectural University of Medicine, Japan
| | - Masakazu Kikai
- Department of Cardiovascular Medicine, Kyoto Prefectural University of Medicine, Japan
| | - Hiroki Takata
- Department of Cardiovascular Medicine, Kyoto Prefectural University of Medicine, Japan
| | - Takehiro Ogata
- Department of Cardiovascular Medicine, Kyoto Prefectural University of Medicine, Japan
| | - Tomomi Ueyama
- Department of Cardiovascular Medicine, Kyoto Prefectural University of Medicine, Japan
| | - Satoaki Matoba
- Department of Cardiovascular Medicine, Kyoto Prefectural University of Medicine, Japan
| | - Hiroyuki Yamada
- Department of Cardiovascular Medicine, Kyoto Prefectural University of Medicine, Japan
| |
Collapse
|
20
|
Saadane A, Mast N, Charvet CD, Omarova S, Zheng W, Huang SS, Kern TS, Peachey NS, Pikuleva IA. Retinal and nonocular abnormalities in Cyp27a1(-/-)Cyp46a1(-/-) mice with dysfunctional metabolism of cholesterol. THE AMERICAN JOURNAL OF PATHOLOGY 2014; 184:2403-19. [PMID: 25065682 DOI: 10.1016/j.ajpath.2014.05.024] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/21/2014] [Revised: 05/21/2014] [Accepted: 05/29/2014] [Indexed: 01/08/2023]
Abstract
Cholesterol elimination from nonhepatic cells involves metabolism to side-chain oxysterols, which serve as transport forms of cholesterol and bioactive molecules modulating a variety of cellular processes. Cholesterol metabolism is tissue specific, and its significance has not yet been established for the retina, where cytochromes P450 (CYP27A1 and CYP46A1) are the major cholesterol-metabolizing enzymes. We generated Cyp27a1(-/-)Cyp46a1(-/-) mice, which were lean and had normal serum cholesterol and glucose levels. These animals, however, had changes in the retinal vasculature, retina, and several nonocular organs (lungs, liver, and spleen). Changes in the retinal vasculature included structural abnormalities (retinal-choroidal anastomoses, arteriovenous shunts, increased permeability, dilation, nonperfusion, and capillary degeneration) and cholesterol deposition and oxidation in the vascular wall, which also exhibited increased adhesion of leukocytes and activation of the complement pathway. Changes in the retina included increased content of cholesterol and its metabolite, cholestanol, which were focally deposited at the apical and basal sides of the retinal pigment epithelium. Retinal macrophages of Cyp27a1(-/-)Cyp46a1(-/-) mice were activated, and oxidative stress was noted in their photoreceptor inner segments. Our findings demonstrate the importance of retinal cholesterol metabolism for maintenance of the normal retina, and suggest new targets for diseases affecting the retinal vasculature.
Collapse
Affiliation(s)
- Aicha Saadane
- Department of Ophthalmology and Visual Sciences, Cleveland, Ohio
| | - Natalia Mast
- Department of Ophthalmology and Visual Sciences, Cleveland, Ohio
| | - Casey D Charvet
- Department of Ophthalmology and Visual Sciences, Cleveland, Ohio
| | - Saida Omarova
- Department of Ophthalmology and Visual Sciences, Cleveland, Ohio
| | - Wenchao Zheng
- Department of Ophthalmology and Visual Sciences, Cleveland, Ohio
| | - Suber S Huang
- Department of Ophthalmology and Visual Sciences, Cleveland, Ohio; Department of Ophthalmology, Cleveland Clinic Lerner College of Medicine, Case Western Reserve University, Cleveland, Ohio
| | - Timothy S Kern
- Department of Medicine, Case Western Reserve University, Cleveland, Ohio
| | - Neal S Peachey
- Cole Eye Institute, Cleveland Clinic Foundation, Cleveland, Ohio; Cleveland VA Medical Center, Cleveland, Ohio; Department of Medicine, University Hospitals, Cleveland, Ohio
| | - Irina A Pikuleva
- Department of Ophthalmology and Visual Sciences, Cleveland, Ohio.
| |
Collapse
|
21
|
Hsu WH, Pan TM. Treatment of metabolic syndrome with ankaflavin, a secondary metabolite isolated from the edible fungus Monascus spp. Appl Microbiol Biotechnol 2014; 98:4853-63. [DOI: 10.1007/s00253-014-5716-5] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2014] [Revised: 03/19/2014] [Accepted: 03/21/2014] [Indexed: 12/31/2022]
|
22
|
Archer A, Laurencikiene J, Ahmed O, Steffensen KR, Parini P, Gustafsson JÅ, Korach-André M. Skeletal muscle as a target of LXR agonist after long-term treatment: focus on lipid homeostasis. Am J Physiol Endocrinol Metab 2014; 306:E494-502. [PMID: 24368671 DOI: 10.1152/ajpendo.00410.2013] [Citation(s) in RCA: 19] [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] [Indexed: 11/22/2022]
Abstract
The liver X receptors (LXR)α and LXRβ are transcription factors belonging to the nuclear receptor family, which play a central role in metabolic homeostasis, being master regulators of key target genes in the glucose and lipid pathways. Wild-type (WT), LXRα(-/-), and LXRβ(-/-) mice were fed a chow diet with (treated) or without (control) the synthetic dual LXR agonist GW3965 for 5 wk. GW3965 raised intrahepatic triglyceride (TG) level but, surprisingly, reduced serum TG level through the activation of serum lipase activity. The serum TG reduction was associated with a repression of both catecholamine-stimulated lipolysis and relative glucose incorporation into lipid in isolated adipocytes through activation of LXRβ. We also demonstrated that LXRα is required for basal (nonstimulated) adipocyte metabolism, whereas LXRβ acts as a repressor of lipolysis. On the contrary, in skeletal muscle (SM), the lipogenic and cholesterol transporter LXR target genes were markedly induced in WT and LXRα(-/-) mice and to a lesser extent in LXRβ(-/-) mice following treatment with GW3965. Moreover, TG content was reduced in SM of LXRβ(-/-) mice, associated with increased expression of the main TG-lipase genes Hsl and Atgl. Energy expenditure was increased, and a switch from glucose to lipid oxidation was observed. In conclusion, we provide evidence that LXR might be an essential regulator of the lipid balance between tissues to ensure appropriate control of the flux of fuel. Importantly, we show that, after chronic treatment with GW3965, SM becomes the target tissue for LXR activation, as opposed to liver, in acute treatment.
Collapse
Affiliation(s)
- Amena Archer
- Department of Biosciences and Nutrition and Center for Biosciences at NOVUM, Karolinska Institute, Huddinge, Sweden
| | | | | | | | | | | | | |
Collapse
|
23
|
Spruiell K, Richardson RM, Cullen JM, Awumey EM, Gonzalez FJ, Gyamfi MA. Role of pregnane X receptor in obesity and glucose homeostasis in male mice. J Biol Chem 2013; 289:3244-61. [PMID: 24362030 DOI: 10.1074/jbc.m113.494575] [Citation(s) in RCA: 70] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023] Open
Abstract
Clinical obesity is a complex metabolic disorder affecting one in three adults. Recent reports suggest that pregnane X receptor (PXR), a xenobiotic nuclear receptor important for defense against toxic agents and for eliminating drugs and other xenobiotics, may be involved in obesity. Noting differences in ligand specificities between human and mouse PXRs, the role of PXR in high fat diet (HFD)-induced obesity was examined using male PXR-humanized (hPXR) transgenic and PXR-knock-out (PXR-KO) mice in comparison to wild-type (WT) mice. After 16 weeks on either a control diet or HFD, WT mice showed greater weight gain, whereas PXR-KO mice gained less weight due to their resistance to HFD-induced decreases in adipose tissue peroxisome proliferator-activated receptor α and induction of hepatic carnitine palmitoyltransferase 1, suggesting increased energy metabolism. Interestingly, control-fed PXR-KO mice exhibited hepatomegaly, hyperinsulinemia, and hyperleptinemia but hypoadiponectinemia and lower adiponectin receptor R2 mRNA levels relative to WT mice. Evaluation of these biologic indicators in hPXR mice fed a control diet or HFD revealed further differences between the mouse and human receptors. Importantly, although HFD-fed hPXR mice were resistant to HFD-induced obesity, both PXR-KO and hPXR mice exhibited impaired induction of glucokinase involved in glucose utilization and displayed elevated fasting glucose levels and severely impaired glucose tolerance. Moreover, the basal hepatic levels of the gluconeogenic enzyme phosphoenolpyruvate carboxykinase 1 were increased in hPXR mice compared with WT mice. Altogether, although the mouse PXR promotes HFD-induced obesity, the hPXR mouse carries a genetic predisposition for type 2 diabetes and thus provides a model for exploring the role of human PXR in the metabolic syndrome.
Collapse
Affiliation(s)
- Krisstonia Spruiell
- From the Julius L. Chambers Biomedical Biotechnology Research Institute, North Carolina Central University, Durham, North Carolina 27707
| | | | | | | | | | | |
Collapse
|
24
|
Wang Q, Dong Z, Liu X, Song X, Song Q, Shang Q, Jiang Y, Guo C, Zhang L. Programmed cell death-4 deficiency prevents diet-induced obesity, adipose tissue inflammation, and insulin resistance. Diabetes 2013; 62:4132-43. [PMID: 23990362 PMCID: PMC3837052 DOI: 10.2337/db13-0097] [Citation(s) in RCA: 44] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
Programmed cell death-4 (PDCD4), a selective protein translation inhibitor, has shown proinflammatory effect in some inflammatory diseases, but its roles in obesity remain unestablished. This study aims to investigate the effects of PDCD4 on obesity, inflammation, and insulin resistance. Surprisingly, high-fat diet (HFD)-fed PDCD4-deficient (PDCD4(-/-)) mice exhibited an absolutely lean phenotype together with improved insulin sensitivity. Compared with wild-type obese mice, HFD-fed PDCD4(-/-) mice showed higher energy expenditure, lower epididymal fat weight, and reduced macrophage infiltration inflammatory cytokine secretion in white adipose tissue (WAT). Alleviated hepatic steatosis along with decreased plasma levels of triglyceride and cholesterol was also observed in these mice. Importantly, PDCD4 appeared to disturb lipid metabolism via inhibiting the expression of liver X receptor (LXR)-α, a master modulator of lipid homeostasis, which was elevated in HFD-fed PDCD4(-/-) mice accompanied by upregulation of its target genes and relieved endoplasmic reticulum stress in WAT. These data demonstrate that PDCD4 deficiency protects mice against diet-induced obesity, WAT inflammation, and insulin resistance through restoring the expression of LXR-α, thereby proposing PDCD4 as a potential target for treating obesity-associated diseases.
Collapse
Affiliation(s)
- Qun Wang
- Department of Immunology, Shandong University School of Medicine, Jinan, Shangdong, China
- Corresponding authors: Qun Wang, , and Lining Zhang,
| | - Zhaojing Dong
- Department of Immunology, Shandong University School of Medicine, Jinan, Shangdong, China
| | - Xianglan Liu
- Department of Immunology, Shandong University School of Medicine, Jinan, Shangdong, China
| | - Xingguo Song
- Department of Immunology, Shandong University School of Medicine, Jinan, Shangdong, China
| | - Qiang Song
- Department of Radiology, Shandong Chest Hospital, Jinan, Shangdong, China
| | - Qianwen Shang
- Department of Immunology, Shandong University School of Medicine, Jinan, Shangdong, China
| | - Yang Jiang
- Department of Immunology, Shandong University School of Medicine, Jinan, Shangdong, China
| | - Chun Guo
- Department of Immunology, Shandong University School of Medicine, Jinan, Shangdong, China
| | - Lining Zhang
- Department of Immunology, Shandong University School of Medicine, Jinan, Shangdong, China
- Corresponding authors: Qun Wang, , and Lining Zhang,
| |
Collapse
|
25
|
LXRα gene expression, genetic variation and association analysis between novel SNPs and growth traits in Chinese native cattle. J Appl Genet 2013; 55:65-74. [DOI: 10.1007/s13353-013-0175-8] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2013] [Revised: 09/08/2013] [Accepted: 09/19/2013] [Indexed: 10/26/2022]
|
26
|
The liver X receptor: A master regulator of the gut–liver axis and a target for non alcoholic fatty liver disease. Biochem Pharmacol 2013; 86:96-105. [DOI: 10.1016/j.bcp.2013.03.016] [Citation(s) in RCA: 53] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2013] [Revised: 03/21/2013] [Accepted: 03/21/2013] [Indexed: 12/15/2022]
|
27
|
Maqdasy S, Baptissart M, Vega A, Baron S, Lobaccaro JMA, Volle DH. Cholesterol and male fertility: what about orphans and adopted? Mol Cell Endocrinol 2013; 368:30-46. [PMID: 22766106 DOI: 10.1016/j.mce.2012.06.011] [Citation(s) in RCA: 48] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/16/2012] [Revised: 06/20/2012] [Accepted: 06/21/2012] [Indexed: 12/24/2022]
Abstract
The link between cholesterol homeostasis and male fertility has been clearly suggested in patients who suffer from hyperlipidemia and metabolic syndrome. This has been confirmed by the generation of several transgenic mouse models or in animals fed with high cholesterol diet. Next to the alteration of the endocrine signaling pathways through steroid receptors (androgen and estrogen receptors); "orphan" and "adopted" nuclear receptors, such as the Liver X Receptors (LXRs), the Proliferating Peroxisomal Activated Receptors (PPARs) or the Liver Receptor Homolog-1 (LRH-1), have been involved in this cross-talk. These transcription factors show distinct expression patterns in the male genital tract, explaining the large panel of phenotypes observed in transgenic male mice and highlighting the importance of lipid homesostasis and the complexity of the molecular pathways involved. Increasing our knowledge of the roles of these nuclear receptors in male germ cell differentiation could help in proposing new approaches to either treat infertile men or define new strategies for contraception.
Collapse
|
28
|
Wang Y, Sul HS. Transcriptional regulation of lipogenesis and its contribution to hepatosteatosis. ACTA ACUST UNITED AC 2013. [DOI: 10.2217/clp.13.11] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
|
29
|
Weissglas-Volkov D, Aguilar-Salinas CA, Nikkola E, Deere KA, Cruz-Bautista I, Arellano-Campos O, Muñoz-Hernandez LL, Gomez-Munguia L, Ordoñez-Sánchez ML, Reddy PMVL, Lusis AJ, Matikainen N, Taskinen MR, Riba L, Cantor RM, Sinsheimer JS, Tusie-Luna T, Pajukanta P. Genomic study in Mexicans identifies a new locus for triglycerides and refines European lipid loci. J Med Genet 2013; 50:298-308. [PMID: 23505323 DOI: 10.1136/jmedgenet-2012-101461] [Citation(s) in RCA: 94] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
BACKGROUND The Mexican population and others with Amerindian heritage exhibit a substantial predisposition to dyslipidemias and coronary heart disease. Yet, these populations remain underinvestigated by genomic studies, and to date, no genome-wide association (GWA) studies have been reported for lipids in these rapidly expanding populations. METHODS AND FINDINGS We performed a two-stage GWA study for hypertriglyceridemia and low high-density lipoprotein cholesterol (HDL-C) in Mexicans (n=4361), and identified a novel Mexican-specific genome-wide significant locus for serum triglycerides (TGs) near the Niemann-Pick type C1 protein gene (p=2.43×10(-08)). Furthermore, three European loci for TGs (APOA5, GCKR and LPL), and four loci for HDL-C (ABCA1, CETP, LIPC and LOC55908) reached genome-wide significance in Mexicans. We used cross-ethnic mapping to narrow three European TG GWA loci, APOA5, MLXIPL, and CILP2 that were wide and contained multiple candidate variants in the European scan. At the APOA5 locus, this reduced the most likely susceptibility variants to one, rs964184. Importantly, our functional analysis demonstrated a direct link between rs964184 and postprandial serum apoAV protein levels, supporting rs964184 as the causative variant underlying the European and Mexican GWA signal. Overall, 52 of the 100 reported associations from European lipid GWA meta-analysis generalised to Mexicans. However, in 82 of the 100 European GWA loci, a different variant other than the European lead/best-proxy variant had the strongest regional evidence of association in Mexicans. CONCLUSIONS This first Mexican GWA study of lipids identified a novel GWA locus for high TG levels; used the interpopulation heterogeneity to significantly restrict three previously known European GWA signals, and surveyed whether the European lipid GWA SNPs extend to the Mexican population.
Collapse
Affiliation(s)
- Daphna Weissglas-Volkov
- Department of Human Genetics, David Geffen School of Medicine at UCLA, Gonda Center, Room 6335B, 695 Charles E. Young Drive South, Los Angeles, CA 90095-7088, USA
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | |
Collapse
|
30
|
Archer A, Stolarczyk E, Doria ML, Helguero L, Domingues R, Howard JK, Mode A, Korach-André M, Gustafsson JÅ. LXR activation by GW3965 alters fat tissue distribution and adipose tissue inflammation in ob/ob female mice. J Lipid Res 2013; 54:1300-11. [PMID: 23446231 DOI: 10.1194/jlr.m033977] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
To investigate the role of liver X receptor (LXR) in adipose tissue metabolism during obesity, ob/ob mice were treated for 5 weeks with the synthetic LXR agonist GW3965. MRI analysis revealed that pharmacological activation of LXR modified fat distribution by decreasing visceral (VS) fat and inversely increasing subcutaneous (SC) fat storage without affecting whole body fat content. This was concordant with opposite regulation by GW3965 of the lipolytic markers hormone-sensitive lipase (HSL) and adipose triglyceride lipase (ATGL) in the two fat depots; moreover, the expression of genes involved in lipogenesis was significantly induced in SC fat. Lipidomic analysis suggested that changes in lipid composition in response to GW3965 also varied between VS and SC fat. In both depots, the observed alteration in lipid composition indicated an overall change toward less lipotoxic lipids. Flow cytometry analysis showed decreased immune cell infiltration in adipose tissue of ob/ob mice in response to GW3965 treatment, which in VS fat mainly affected the macrophage population and in SC fat the lymphocyte population. In line with this, the expression and secretion of proinflammatory markers was decreased in both fat deposits with GW3965 treatment.
Collapse
Affiliation(s)
- Amena Archer
- Department of Biosciences and Nutrition, Karolinska Insitutet, Huddinge, Sweden, TX, USA.
| | | | | | | | | | | | | | | | | |
Collapse
|
31
|
Hsu WH, Huang YC, Lee BH, Hsu YW, Pan TM. The improvements of ankaflavin isolated from Monascus-fermented products on dyslipidemia in high-fat diet-induced hasmster. J Funct Foods 2013. [DOI: 10.1016/j.jff.2012.11.016] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023] Open
|
32
|
Archer A, Venteclef N, Mode A, Pedrelli M, Gabbi C, Clément K, Parini P, Gustafsson JÅ, Korach-André M. Fasting-induced FGF21 is repressed by LXR activation via recruitment of an HDAC3 corepressor complex in mice. Mol Endocrinol 2012; 26:1980-90. [PMID: 23073827 DOI: 10.1210/me.2012-1151] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
The liver plays a pivotal role in the physiological adaptation to fasting and a better understanding of the metabolic adaptive responses may give hints on new therapeutic strategies to control the metabolic diseases. The liver X receptors (LXRs) are well-established regulators of lipid and glucose metabolism. More recently fibroblast growth factor 21 (FGF21) has emerged as an important regulator of energy homeostasis. We hypothesized that the LXR transcription factors could influence Fgf21 expression, which is induced in response to fasting. Wild-type, LXRα(-/-), and LXRβ(-/-) mice were treated for 3 d with vehicle or the LXR agonist GW3965 and fasted for 12 h prior to the killing of the animals. Interestingly, serum FGF21 levels were induced after fasting, but this increase was blunted when the mice were treated with GW3965 independently of genotypes. Compared with wild-type mice, GW3965-treated LXRα(-/-) and LXRβ(-/-) mice showed improved insulin sensitivity and enhanced ketogenic response at fasting. Of note is that during fasting, GW3965 treatment tended to reduce liver triglycerides as opposed to the effect of the agonist in the fed state. The LXR-dependent repression of Fgf21 seems to be mainly mediated by the recruitment of LXRβ onto the Fgf21 promoter upon GW3965 treatment. This repression by LXRβ occurs through the recruitment and stabilization of the repressor complex composed of retinoid-related orphan receptor-α/Rev-Erbα/histone deacetylase 3 onto the Fgf21 promoter. Our data clearly demonstrate that there is a cross talk between the LXR and FGF21 signaling pathways in the adaptive response to fasting.
Collapse
Affiliation(s)
- Amena Archer
- Department of Biosciences and Nutrition and Center for Biosciences at Novum, Karolinska Institute, S-141 83 Huddinge, Sweden
| | | | | | | | | | | | | | | | | |
Collapse
|
33
|
Polyzos SA, Kountouras J, Mantzoros CS. Sulfated oxysterols as candidates for the treatment of nonalcoholic fatty liver disease. Metabolism 2012; 61:755-8. [PMID: 22386938 DOI: 10.1016/j.metabol.2012.01.020] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/18/2012] [Accepted: 01/19/2012] [Indexed: 01/23/2023]
|
34
|
Cruz-Garcia L, Sánchez-Gurmaches J, Gutiérrez J, Navarro I. Role of LXR in trout adipocytes: target genes, hormonal regulation, adipocyte differentiation and relation to lipolysis. Comp Biochem Physiol A Mol Integr Physiol 2012; 163:120-6. [PMID: 22626869 DOI: 10.1016/j.cbpa.2012.05.193] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2012] [Revised: 05/16/2012] [Accepted: 05/16/2012] [Indexed: 11/18/2022]
Abstract
In the present study, we describe an initial approach to investigate the role of LXR in fish adipose tissue. Rainbow trout (Oncorhynchus mykiss) isolated adipocytes were incubated with LXR agonists, unsaturated fatty acids, tumour necrosis factor-α (TNFα), insulin or growth hormone (GH) for 6h and LXR expression was analyzed. Lipolysis was measured after incubation with one of the LXR agonists and LXR expression was compared with levels of lipolysis. LXR expression was also analyzed during the differentiation of adipocytes in culture. The incubations with agonists in isolated adipocytes indicated that ATP-binding cassette transporter A1 (ABCA1) is an LXR target gene, but lipoprotein lipase (LPL), fatty acid synthase (FAS), hormone-sensitive lipase (HSL) and peroxisome proliferator-activated receptor (PPARs) are not. LXR agonists also induced LXR expression and raised lipolysis levels. Besides, LXR expression was upregulated in parallel with basal lipolysis. LXR mRNA expression was regulated by unsaturated fatty acids, insulin, TNFα and GH in isolated adipocytes. Besides, LXR showed an upregulation during adipocyte differentiation. All these data indicate that LXR is involved in orchestrating the transcriptional regulatory network in trout adipocyte lipid metabolism, specifically, in cholesterol transport, adipocyte differentiation and lipolysis.
Collapse
Affiliation(s)
- Lourdes Cruz-Garcia
- Departament de Fisiologia, Facultat de Biologia, Universitat de Barcelona, 08028 Barcelona, Spain.
| | | | | | | |
Collapse
|
35
|
Transcriptional integration of metabolism by the nuclear sterol-activated receptors LXR and FXR. Nat Rev Mol Cell Biol 2012; 13:213-24. [PMID: 22414897 DOI: 10.1038/nrm3312] [Citation(s) in RCA: 545] [Impact Index Per Article: 45.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
Nuclear receptors are integrators of hormonal and nutritional signals, mediating changes to metabolic pathways within the body. Given that modulation of lipid and glucose metabolism has been linked to diseases including type 2 diabetes, obesity and atherosclerosis, a greater understanding of pathways that regulate metabolism in physiology and disease is crucial. The liver X receptors (LXRs) and the farnesoid X receptors (FXRs) are activated by oxysterols and bile acids, respectively. Mounting evidence indicates that these nuclear receptors have essential roles, not only in the regulation of cholesterol and bile acid metabolism but also in the integration of sterol, fatty acid and glucose metabolism.
Collapse
|
36
|
Abstract
Liver X receptors (LXRs) are members of the nuclear receptor family and are present in two isoforms, α and β, encoded by two separate genes. Originally described in the liver, LXRs have in the last 15 years been implicated in central metabolic pathways, including bile acid synthesis, lipid and glucose homeostasis. Although the vast majority of studies have been performed in non-adipose cells/tissues, results in recent years suggest that LXRs may have important modulatory roles in adipose tissue and adipocytes. Although several authors have published reviews on LXR, there have been no attempts to summarize the effects reported specifically in adipose systems. This overview gives a brief introduction to LXR and describes the sometimes-contradictory results obtained in murine cell systems and in rodent adipose tissue. The so far very limited number of studies performed in human adipocytes and adipose tissue are also presented. It should be apparent that although LXR may impact on several different pathways in metabolism, the clinical role of LXR modulation in adipose tissue is still not clear.
Collapse
|
37
|
Zhu R, Ou Z, Ruan X, Gong J. Role of liver X receptors in cholesterol efflux and inflammatory signaling (review). Mol Med Rep 2012; 5:895-900. [PMID: 22267249 PMCID: PMC3493071 DOI: 10.3892/mmr.2012.758] [Citation(s) in RCA: 53] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2011] [Accepted: 12/27/2011] [Indexed: 01/10/2023] Open
Abstract
Liver X receptors (LXRs) are nuclear receptors that play a central role in cholesterol metabolism. When activated, LXRs induce a series of genes that are involved in cholesterol efflux, absorption, transport and excretion. In recent studies, LXRs have also been shown to play an important role in inflammatory signaling. LXR agonists show promise as potential therapeutics, given their anti-atherogenic and anti-inflammatory properties. The function of LXRs in cholesterol efflux and inflammatory signaling make them attractive as therapies for cardiovascular and inflammatory diseases.
Collapse
Affiliation(s)
- Rongtao Zhu
- Department of Hepatobiliary Surgery, The Second Affiliated Hospital, Chongqing Medical University, Chongqing 400010, PR China
| | | | | | | |
Collapse
|
38
|
Archer A, Srinivas Kitambi S, L. Hallgren S, Pedrelli M, Håkan Olsén K, Mode A, Gustafsson JÅ. The Liver X-Receptor (Lxr) Governs Lipid Homeostasis in Zebrafish during Development. ACTA ACUST UNITED AC 2012. [DOI: 10.4236/ojemd.2012.24012] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
|
39
|
Liver X Receptor: an oxysterol sensor and a major player in the control of lipogenesis. Chem Phys Lipids 2011; 164:500-14. [PMID: 21693109 DOI: 10.1016/j.chemphyslip.2011.06.004] [Citation(s) in RCA: 49] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2011] [Revised: 06/04/2011] [Accepted: 06/06/2011] [Indexed: 01/12/2023]
Abstract
De novo fatty acid biosynthesis is also called lipogenesis. It is a metabolic pathway that provides the cells with fatty acids required for major cellular processes such as energy storage, membrane structures and lipid signaling. In this article we will review the role of the Liver X Receptors (LXRs), nuclear receptors that sense oxysterols, in the transcriptional regulation of genes involved in lipogenesis.
Collapse
|