201
|
IL-15/sIL-15Rα gene transfer induces weight loss and improves glucose homeostasis in obese mice. Gene Ther 2016; 23:349-56. [PMID: 26752354 DOI: 10.1038/gt.2016.4] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2015] [Revised: 11/29/2015] [Accepted: 12/31/2015] [Indexed: 02/06/2023]
Abstract
Obesity and its associated metabolic problems are a major public health issue. The objective of the current study is to investigate the therapeutic effects of interleukin 15/soluble interleukin 15 receptor-α (IL-15/sIL-15Rα) on high-fat diet-induced obesity and obesity-associated metabolic disorders. We demonstrate that the multiple hydrodynamic delivery of 2 μg IL-15/sIL-15Rα plasmid results in numerous beneficial effects, including a reduction of body weight and fat mass, an alleviation of fatty liver, an improvement in glucose homeostasis and insulin sensitivity in obese mice. These effects are accompanied by a suppressed expression of genes involved in lipid accumulation and lipogenesis, including Pparγ, Cd36, Fabp4, Mgat1, Scd-1 and Fas, and elevated mRNA levels of genes involved in adaptive thermogenesis and fatty acid β-oxidation, such as Ucp1, Ucp3, Pgc-1α, Pgc-1β, Pparα, Pparδ, Cpt1-α and Cpt1-β in obese animals. These results suggest that the overexpression of the Il-15/sIl-15Rα gene is an effective approach in treating diet-induced obesity and its associated metabolic complications.
Collapse
|
202
|
Mwangi SM, Peng S, Nezami BG, Thorn N, Farris AB, Jain S, Laroui H, Merlin D, Anania F, Srinivasan S. Glial cell line-derived neurotrophic factor protects against high-fat diet-induced hepatic steatosis by suppressing hepatic PPAR-γ expression. Am J Physiol Gastrointest Liver Physiol 2016; 310:G103-16. [PMID: 26564715 PMCID: PMC4719063 DOI: 10.1152/ajpgi.00196.2015] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/22/2015] [Accepted: 11/02/2015] [Indexed: 01/31/2023]
Abstract
Glial cell line-derived neurotrophic factor (GDNF) protects against high-fat diet (HFD)-induced hepatic steatosis in mice, however, the mechanisms involved are not known. In this study we investigated the effects of GDNF overexpression and nanoparticle delivery of GDNF in mice on hepatic steatosis and fibrosis and the expression of genes involved in the regulation of hepatic lipid uptake and de novo lipogenesis. Transgenic overexpression of GDNF in liver and other metabolically active tissues was protective against HFD-induced hepatic steatosis. Mice overexpressing GDNF had significantly reduced P62/sequestosome 1 protein levels suggestive of accelerated autophagic clearance. They also had significantly reduced peroxisome proliferator-activated receptor-γ (PPAR-γ) and CD36 gene expression and protein levels, and lower expression of mRNA coding for enzymes involved in de novo lipogenesis. GDNF-loaded nanoparticles were protective against short-term HFD-induced hepatic steatosis and attenuated liver fibrosis in mice with long-standing HFD-induced hepatic steatosis. They also suppressed the liver expression of steatosis-associated genes. In vitro, GDNF suppressed triglyceride accumulation in Hep G2 cells through enhanced p38 mitogen-activated protein kinase-dependent signaling and inhibition of PPAR-γ gene promoter activity. These results show that GDNF acts directly in the liver to protect against HFD-induced cellular stress and that GDNF may have a role in the treatment of nonalcoholic fatty liver disease.
Collapse
Affiliation(s)
- Simon Musyoka Mwangi
- 1Division of Digestive Diseases, Emory University School of Medicine, Atlanta, Georgia; ,2Atlanta Veterans Affairs Medical Center, Decatur, Georgia;
| | - Sophia Peng
- 1Division of Digestive Diseases, Emory University School of Medicine, Atlanta, Georgia;
| | - Behtash Ghazi Nezami
- 1Division of Digestive Diseases, Emory University School of Medicine, Atlanta, Georgia; ,2Atlanta Veterans Affairs Medical Center, Decatur, Georgia;
| | - Natalie Thorn
- 1Division of Digestive Diseases, Emory University School of Medicine, Atlanta, Georgia; ,2Atlanta Veterans Affairs Medical Center, Decatur, Georgia;
| | - Alton B. Farris
- 3Department of Pathology and Laboratory Medicine, Emory University, Atlanta, Georgia;
| | - Sanjay Jain
- 5Internal Medicine (Renal Division), Washington University School of Medicine, St. Louis, Missouri
| | - Hamed Laroui
- 4Institute for Biomedical Sciences, Georgia State University, Atlanta, Georgia; and
| | - Didier Merlin
- 2Atlanta Veterans Affairs Medical Center, Decatur, Georgia; ,4Institute for Biomedical Sciences, Georgia State University, Atlanta, Georgia; and
| | - Frank Anania
- 1Division of Digestive Diseases, Emory University School of Medicine, Atlanta, Georgia; ,2Atlanta Veterans Affairs Medical Center, Decatur, Georgia;
| | - Shanthi Srinivasan
- Division of Digestive Diseases, Emory University School of Medicine, Atlanta, Georgia; Atlanta Veterans Affairs Medical Center, Decatur, Georgia;
| |
Collapse
|
203
|
Ham JR, Lee HI, Choi RY, Sim MO, Seo KI, Lee MK. Anti-steatotic and anti-inflammatory roles of syringic acid in high-fat diet-induced obese mice. Food Funct 2016; 7:689-697. [DOI: 10.1039/c5fo01329a] [Citation(s) in RCA: 71] [Impact Index Per Article: 8.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 08/29/2023]
Abstract
This study examined the effects of syringic acid (SA) on obese diet-induced hepatic dysfunction.
Collapse
Affiliation(s)
- Ju Ri Ham
- Department of Food and Nutrition
- Sunchon National University
- Suncheon
- Korea
| | - Hae-In Lee
- Mokpo Marin Food-Industry Research Center
- Mokpo
- Korea
| | - Ra-Yeong Choi
- Department of Food and Nutrition
- Sunchon National University
- Suncheon
- Korea
| | - Mi-Ok Sim
- Jeollanamdo Development Institute of Korean Traditional Medicine
- Jangheung
- Korea
| | - Kwon-Il Seo
- Department of Biotechnology
- Dong-A University
- Busan
- Korea
| | - Mi-Kyung Lee
- Department of Food and Nutrition
- Sunchon National University
- Suncheon
- Korea
- Suncheon Research Center for Natural Medicines
| |
Collapse
|
204
|
Zhu YX, Zhang ML, Zhong Y, Wang C, Jia WP. Modulation Effect of Peroxisome Proliferator-Activated Receptor Agonists on Lipid Droplet Proteins in Liver. J Diabetes Res 2016; 2016:8315454. [PMID: 26770990 PMCID: PMC4684860 DOI: 10.1155/2016/8315454] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/06/2014] [Revised: 06/02/2015] [Accepted: 07/01/2015] [Indexed: 12/14/2022] Open
Abstract
Peroxisome proliferator-activated receptor (PPAR) agonists are used for treating hyperglycemia and type 2 diabetes. However, the mechanism of action of these agonists is still under investigation. The lipid droplet-associated proteins FSP27/CIDEC and LSDP5, regulated directly by PPARγ and PPARα, are associated with hepatic steatosis and insulin sensitivity. Here, we evaluated the expression levels of FSP27/CIDEC and LSDP5 and the regulation of these proteins by consumption of a high-fat diet (HFD) or administration of PPAR agonists. Mice with diet-induced obesity were treated with the PPARγ or PPARα agonist, pioglitazone or fenofibrate, respectively. Liver tissues from db/db diabetic mice and human were also collected. Interestingly, FSP27/CIEDC was expressed in mouse and human livers and was upregulated in obese C57BL/6J mice. Fenofibrate treatment decreased hepatic triglyceride (TG) content and FSP27/CIDEC protein expression in mice fed an HFD diet. In mice, LSDP5 was not detected, even in the context of insulin resistance or treatment with PPAR agonists. However, LSDP5 was highly expressed in humans, with elevated expression observed in the fatty liver. We concluded that fenofibrate greatly decreased hepatic TG content and FSP27/CIDEC protein expression in mice fed an HFD, suggesting a potential regulatory role for fenofibrate in the amelioration of hepatic steatosis.
Collapse
Affiliation(s)
- Yun-Xia Zhu
- Department of Geriatrics, Shanghai Jiao Tong University Affiliated Sixth People's Hospital, 600 Yishan Road, Shanghai 200233, China
| | - Ming-Liang Zhang
- Department of Endocrinology and Metabolism, Shanghai Jiao Tong University Affiliated Sixth People's Hospital, 600 Yishan Road, Shanghai 200233, China
| | - Yuan Zhong
- Department of Geriatrics, Shanghai Jiao Tong University Affiliated Sixth People's Hospital, 600 Yishan Road, Shanghai 200233, China
| | - Chen Wang
- Department of Endocrinology and Metabolism, Shanghai Jiao Tong University Affiliated Sixth People's Hospital, 600 Yishan Road, Shanghai 200233, China
- Shanghai Key Laboratory of Diabetes Mellitus, 600 Yishan Road, Shanghai 200233, China
- Shanghai Diabetes Institute, Shanghai Jiao Tong University Affiliated Sixth People's Hospital, 600 Yishan Road, Shanghai 200233, China
- *Chen Wang:
| | - Wei-Ping Jia
- Department of Endocrinology and Metabolism, Shanghai Jiao Tong University Affiliated Sixth People's Hospital, 600 Yishan Road, Shanghai 200233, China
- Shanghai Key Laboratory of Diabetes Mellitus, 600 Yishan Road, Shanghai 200233, China
- Shanghai Diabetes Institute, Shanghai Jiao Tong University Affiliated Sixth People's Hospital, 600 Yishan Road, Shanghai 200233, China
| |
Collapse
|
205
|
Ge Z, Zhang P, Hong T, Tang S, Meng R, Bi Y, Zhu D. Erythropoietin alleviates hepatic insulin resistance via PPARγ-dependent AKT activation. Sci Rep 2015; 5:17878. [PMID: 26643367 PMCID: PMC4672330 DOI: 10.1038/srep17878] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2015] [Accepted: 11/06/2015] [Indexed: 12/30/2022] Open
Abstract
Erythropoietin (EPO) has beneficial effects on glucose metabolism and insulin resistance. However, the mechanism underlying these effects has not yet been elucidated. This study aimed to investigate how EPO affects hepatic glucose metabolism. Here, we report that EPO administration promoted phosphatidylinositol 3-kinase (PI3K)/AKT pathway activation in palmitic acid (PA)-treated HepG2 cells and in the liver of high-fat diet (HFD)-fed mice, whereas adenovirus-mediated silencing of the erythropoietin receptor (EPOR) blocked EPO-induced AKT signalling in HepG2 cells. Importantly, a peroxisome proliferator-activated receptor γ (PPARγ) antagonist and PPARγ small interfering RNA (siRNA) abrogated the EPO-induced increase in p-AKT in HepG2 cells. Lentiviral vector-mediated hepatic PPARγ silencing in HFD-fed C57BL/6 mice impaired EPO-mediated increases in glucose tolerance, insulin sensitivity and hepatic AKT activation. Furthermore, EPO activated the AMP-activated protein kinase (AMPK)/sirtuin 1 (SIRT1) signalling pathway, and AMPKα and SIRT1 knockdown each attenuated the EPO-induced PPARγ expression and deacetylation and PPARγ-dependent AKT activation in HepG2 cells. In summary, these findings suggest that PPARγ is involved in EPO/EPOR-induced AKT activation, and targeting the PPARγ/AKT pathway via EPO may have therapeutic implications for hepatic insulin resistance and type 2 diabetes.
Collapse
Affiliation(s)
- Zhijuan Ge
- Department of Endocrinology, DrumTower hospital affiliated to Nanjing University Medical School, No321 Zhongshan Road, Nanjing, 210008, China
| | - Pengzi Zhang
- Department of Endocrinology, DrumTower hospital affiliated to Nanjing University Medical School, No321 Zhongshan Road, Nanjing, 210008, China
| | - Ting Hong
- Department of Endocrinology, Drum Tower Clinical Medical College of Nanjing Medical University, Nanjing, 210008, China
| | - Sunyinyan Tang
- Department of Endocrinology, DrumTower hospital affiliated to Nanjing University Medical School, No321 Zhongshan Road, Nanjing, 210008, China
| | - Ran Meng
- Department of Endocrinology, DrumTower hospital affiliated to Nanjing University Medical School, No321 Zhongshan Road, Nanjing, 210008, China
| | - Yan Bi
- Department of Endocrinology, DrumTower hospital affiliated to Nanjing University Medical School, No321 Zhongshan Road, Nanjing, 210008, China
| | - Dalong Zhu
- Department of Endocrinology, DrumTower hospital affiliated to Nanjing University Medical School, No321 Zhongshan Road, Nanjing, 210008, China
| |
Collapse
|
206
|
Chen J, Wang W, Qi Y, Kaczorowski D, McCaughan GW, Gamble JR, Don AS, Gao X, Vadas MA, Xia P. Deletion of sphingosine kinase 1 ameliorates hepatic steatosis in diet-induced obese mice: Role of PPARγ. Biochim Biophys Acta Mol Cell Biol Lipids 2015; 1861:138-147. [PMID: 26615875 DOI: 10.1016/j.bbalip.2015.11.006] [Citation(s) in RCA: 39] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2015] [Revised: 10/03/2015] [Accepted: 11/09/2015] [Indexed: 12/19/2022]
Abstract
Sphingolipid metabolites have emerged playing important roles in the pathogenesis of nonalcoholic fatty liver disease, whereas the underlying mechanism remains largely unknown. In the present study, we provide both in vitro and in vivo evidence showing a pathogenic role of sphingosine kinase 1 (SphK1) in hepatocellular steatosis. We found that levels of SphK1 expression were significantly increased in steatotic hepatocytes. Enforced overexpression of SphK1 or treatment with sphingosine 1-phosphate (S1P) markedly enhanced hepatic lipid accumulation. In contrast, the siRNA-mediated knockdown of SphK1 or S1P receptors, S1P2 and S1P3, profoundly inhibited lipid accumulation in hepatocytes. Moreover, Sphk1(-/-) mice exhibited a significant amelioration of hepatosteatosis under diet-induced obese (DIO) conditions, compared to wild-type littermates. In addition, DIO-induced up-regulation of PPARγ and its target genes were significantly reduced by SphK1 deficiency. Furthermore, treatment of hepatocytes with S1P induces a dose-dependent increase in PPARγ expression at the transcriptional level. Blockage of S1P receptors and the Akt-mTOR signaling profoundly inhibited S1P-induced PPARγ expression. Notably, down-regulation of PPARγ by using its siRNA significantly diminished the pro-steatotic effect of SphK1/S1P. Thus, the study demonstrates a new pathway connecting SphK1 and PPARγ involved in the pathogenesis of hepatocellular steatosis.
Collapse
Affiliation(s)
- Jinbiao Chen
- Centenary Institute, The University of Sydney, Sydney, Australia
| | - Wei Wang
- Department of Endocrinology and Metabolism, Zhongshan Hospital, and Institute of Chronic Metabolic Diseases, Fudan University, Shanghai, China
| | - Yanfei Qi
- Centenary Institute, The University of Sydney, Sydney, Australia
| | | | | | | | - Anthony S Don
- Lowy Cancer Research Centre and Prince of Wales Clinical School, University of New South Wales, Sydney, Australia
| | - Xin Gao
- Department of Endocrinology and Metabolism, Zhongshan Hospital, and Institute of Chronic Metabolic Diseases, Fudan University, Shanghai, China
| | - Mathew A Vadas
- Centenary Institute, The University of Sydney, Sydney, Australia
| | - Pu Xia
- Centenary Institute, The University of Sydney, Sydney, Australia; Department of Endocrinology and Metabolism, Zhongshan Hospital, and Institute of Chronic Metabolic Diseases, Fudan University, Shanghai, China.
| |
Collapse
|
207
|
Ammirati M, Bagley SW, Bhattacharya SK, Buckbinder L, Carlo AA, Conrad R, Cortes C, Dow RL, Dowling MS, El-Kattan A, Ford K, Guimarães CRW, Hepworth D, Jiao W, LaPerle J, Liu S, Londregan A, Loria PM, Mathiowetz AM, Munchhof M, Orr STM, Petersen DN, Price DA, Skoura A, Smith AC, Wang J. Discovery of an in Vivo Tool to Establish Proof-of-Concept for MAP4K4-Based Antidiabetic Treatment. ACS Med Chem Lett 2015; 6:1128-33. [PMID: 26617966 DOI: 10.1021/acsmedchemlett.5b00215] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2015] [Accepted: 09/28/2015] [Indexed: 01/12/2023] Open
Abstract
Recent studies in adipose tissue, pancreas, muscle, and macrophages suggest that MAP4K4, a serine/threonine protein kinase may be a viable target for antidiabetic drugs. As part of the evaluation of MAP4K4 as a novel antidiabetic target, a tool compound, 16 (PF-6260933) and a lead 17 possessing excellent kinome selectivity and suitable properties were delivered to establish proof of concept in vivo. The medicinal chemistry effort that led to the discovery of these lead compounds is described herein together with in vivo pharmacokinetic properties and activity in a model of insulin resistance.
Collapse
Affiliation(s)
- Mark Ammirati
- Worldwide Medicinal Chemistry, ‡Cardiovascular and Metabolic Research Unit, §External Research Solutions, ∥Primary Pharmacology Group, and ⊥Pharmacokinetics, Dynamics and Metabolism, Pfizer Worldwide Research & Development, 610 Main Street, Cambridge, Massachusetts 02139, United States
| | - Scott W. Bagley
- Worldwide Medicinal Chemistry, ‡Cardiovascular and Metabolic Research Unit, §External Research Solutions, ∥Primary Pharmacology Group, and ⊥Pharmacokinetics, Dynamics and Metabolism, Pfizer Worldwide Research & Development, 610 Main Street, Cambridge, Massachusetts 02139, United States
| | - Samit K. Bhattacharya
- Worldwide Medicinal Chemistry, ‡Cardiovascular and Metabolic Research Unit, §External Research Solutions, ∥Primary Pharmacology Group, and ⊥Pharmacokinetics, Dynamics and Metabolism, Pfizer Worldwide Research & Development, 610 Main Street, Cambridge, Massachusetts 02139, United States
| | - Leonard Buckbinder
- Worldwide Medicinal Chemistry, ‡Cardiovascular and Metabolic Research Unit, §External Research Solutions, ∥Primary Pharmacology Group, and ⊥Pharmacokinetics, Dynamics and Metabolism, Pfizer Worldwide Research & Development, 610 Main Street, Cambridge, Massachusetts 02139, United States
| | - Anthony A. Carlo
- Worldwide Medicinal Chemistry, ‡Cardiovascular and Metabolic Research Unit, §External Research Solutions, ∥Primary Pharmacology Group, and ⊥Pharmacokinetics, Dynamics and Metabolism, Pfizer Worldwide Research & Development, 610 Main Street, Cambridge, Massachusetts 02139, United States
| | - Rebecca Conrad
- Worldwide Medicinal Chemistry, ‡Cardiovascular and Metabolic Research Unit, §External Research Solutions, ∥Primary Pharmacology Group, and ⊥Pharmacokinetics, Dynamics and Metabolism, Pfizer Worldwide Research & Development, 610 Main Street, Cambridge, Massachusetts 02139, United States
| | - Christian Cortes
- Worldwide Medicinal Chemistry, ‡Cardiovascular and Metabolic Research Unit, §External Research Solutions, ∥Primary Pharmacology Group, and ⊥Pharmacokinetics, Dynamics and Metabolism, Pfizer Worldwide Research & Development, 610 Main Street, Cambridge, Massachusetts 02139, United States
| | - Robert L. Dow
- Worldwide Medicinal Chemistry, ‡Cardiovascular and Metabolic Research Unit, §External Research Solutions, ∥Primary Pharmacology Group, and ⊥Pharmacokinetics, Dynamics and Metabolism, Pfizer Worldwide Research & Development, 610 Main Street, Cambridge, Massachusetts 02139, United States
| | - Matthew S. Dowling
- Worldwide Medicinal Chemistry, ‡Cardiovascular and Metabolic Research Unit, §External Research Solutions, ∥Primary Pharmacology Group, and ⊥Pharmacokinetics, Dynamics and Metabolism, Pfizer Worldwide Research & Development, 610 Main Street, Cambridge, Massachusetts 02139, United States
| | - Ayman El-Kattan
- Worldwide Medicinal Chemistry, ‡Cardiovascular and Metabolic Research Unit, §External Research Solutions, ∥Primary Pharmacology Group, and ⊥Pharmacokinetics, Dynamics and Metabolism, Pfizer Worldwide Research & Development, 610 Main Street, Cambridge, Massachusetts 02139, United States
| | - Kristen Ford
- Worldwide Medicinal Chemistry, ‡Cardiovascular and Metabolic Research Unit, §External Research Solutions, ∥Primary Pharmacology Group, and ⊥Pharmacokinetics, Dynamics and Metabolism, Pfizer Worldwide Research & Development, 610 Main Street, Cambridge, Massachusetts 02139, United States
| | - Cristiano R. W. Guimarães
- Worldwide Medicinal Chemistry, ‡Cardiovascular and Metabolic Research Unit, §External Research Solutions, ∥Primary Pharmacology Group, and ⊥Pharmacokinetics, Dynamics and Metabolism, Pfizer Worldwide Research & Development, 610 Main Street, Cambridge, Massachusetts 02139, United States
| | - David Hepworth
- Worldwide Medicinal Chemistry, ‡Cardiovascular and Metabolic Research Unit, §External Research Solutions, ∥Primary Pharmacology Group, and ⊥Pharmacokinetics, Dynamics and Metabolism, Pfizer Worldwide Research & Development, 610 Main Street, Cambridge, Massachusetts 02139, United States
| | - Wenhua Jiao
- Worldwide Medicinal Chemistry, ‡Cardiovascular and Metabolic Research Unit, §External Research Solutions, ∥Primary Pharmacology Group, and ⊥Pharmacokinetics, Dynamics and Metabolism, Pfizer Worldwide Research & Development, 610 Main Street, Cambridge, Massachusetts 02139, United States
| | - Jennifer LaPerle
- Worldwide Medicinal Chemistry, ‡Cardiovascular and Metabolic Research Unit, §External Research Solutions, ∥Primary Pharmacology Group, and ⊥Pharmacokinetics, Dynamics and Metabolism, Pfizer Worldwide Research & Development, 610 Main Street, Cambridge, Massachusetts 02139, United States
| | - Shenping Liu
- Worldwide Medicinal Chemistry, ‡Cardiovascular and Metabolic Research Unit, §External Research Solutions, ∥Primary Pharmacology Group, and ⊥Pharmacokinetics, Dynamics and Metabolism, Pfizer Worldwide Research & Development, 610 Main Street, Cambridge, Massachusetts 02139, United States
| | - Allyn Londregan
- Worldwide Medicinal Chemistry, ‡Cardiovascular and Metabolic Research Unit, §External Research Solutions, ∥Primary Pharmacology Group, and ⊥Pharmacokinetics, Dynamics and Metabolism, Pfizer Worldwide Research & Development, 610 Main Street, Cambridge, Massachusetts 02139, United States
| | - Paula M. Loria
- Worldwide Medicinal Chemistry, ‡Cardiovascular and Metabolic Research Unit, §External Research Solutions, ∥Primary Pharmacology Group, and ⊥Pharmacokinetics, Dynamics and Metabolism, Pfizer Worldwide Research & Development, 610 Main Street, Cambridge, Massachusetts 02139, United States
| | - Alan M. Mathiowetz
- Worldwide Medicinal Chemistry, ‡Cardiovascular and Metabolic Research Unit, §External Research Solutions, ∥Primary Pharmacology Group, and ⊥Pharmacokinetics, Dynamics and Metabolism, Pfizer Worldwide Research & Development, 610 Main Street, Cambridge, Massachusetts 02139, United States
| | - Michael Munchhof
- Worldwide Medicinal Chemistry, ‡Cardiovascular and Metabolic Research Unit, §External Research Solutions, ∥Primary Pharmacology Group, and ⊥Pharmacokinetics, Dynamics and Metabolism, Pfizer Worldwide Research & Development, 610 Main Street, Cambridge, Massachusetts 02139, United States
| | - Suvi T. M. Orr
- Worldwide Medicinal Chemistry, ‡Cardiovascular and Metabolic Research Unit, §External Research Solutions, ∥Primary Pharmacology Group, and ⊥Pharmacokinetics, Dynamics and Metabolism, Pfizer Worldwide Research & Development, 610 Main Street, Cambridge, Massachusetts 02139, United States
| | - Donna N. Petersen
- Worldwide Medicinal Chemistry, ‡Cardiovascular and Metabolic Research Unit, §External Research Solutions, ∥Primary Pharmacology Group, and ⊥Pharmacokinetics, Dynamics and Metabolism, Pfizer Worldwide Research & Development, 610 Main Street, Cambridge, Massachusetts 02139, United States
| | - David A. Price
- Worldwide Medicinal Chemistry, ‡Cardiovascular and Metabolic Research Unit, §External Research Solutions, ∥Primary Pharmacology Group, and ⊥Pharmacokinetics, Dynamics and Metabolism, Pfizer Worldwide Research & Development, 610 Main Street, Cambridge, Massachusetts 02139, United States
| | - Athanasia Skoura
- Worldwide Medicinal Chemistry, ‡Cardiovascular and Metabolic Research Unit, §External Research Solutions, ∥Primary Pharmacology Group, and ⊥Pharmacokinetics, Dynamics and Metabolism, Pfizer Worldwide Research & Development, 610 Main Street, Cambridge, Massachusetts 02139, United States
| | - Aaron C. Smith
- Worldwide Medicinal Chemistry, ‡Cardiovascular and Metabolic Research Unit, §External Research Solutions, ∥Primary Pharmacology Group, and ⊥Pharmacokinetics, Dynamics and Metabolism, Pfizer Worldwide Research & Development, 610 Main Street, Cambridge, Massachusetts 02139, United States
| | - Jian Wang
- Worldwide Medicinal Chemistry, ‡Cardiovascular and Metabolic Research Unit, §External Research Solutions, ∥Primary Pharmacology Group, and ⊥Pharmacokinetics, Dynamics and Metabolism, Pfizer Worldwide Research & Development, 610 Main Street, Cambridge, Massachusetts 02139, United States
| |
Collapse
|
208
|
Interactions between Myc and Mediators of Inflammation in Chronic Liver Diseases. Mediators Inflamm 2015; 2015:276850. [PMID: 26508814 PMCID: PMC4609837 DOI: 10.1155/2015/276850] [Citation(s) in RCA: 53] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2014] [Accepted: 11/26/2014] [Indexed: 02/06/2023] Open
Abstract
Most chronic liver diseases (CLDs) are characterized by inflammatory processes with aberrant expressions of various pro- and anti-inflammatory mediators in the liver. These mediators are the driving force of many inflammatory liver disorders, which often result in fibrosis, cirrhosis, and liver tumorigenesis. c-Myc is involved in many cellular events such as cell growth, proliferation, and differentiation. c-Myc upregulates IL-8, IL-10, TNF-α, and TGF-β, while IL-1, IL-2, IL-4, TNF-α, and TGF-β promote c-Myc expression. Their interactions play a central role in fibrosis, cirrhosis, and liver cancer. Molecular interference of their interactions offers possible therapeutic potential for CLDs. In this review, current knowledge of the molecular interactions between c-Myc and various well known inflammatory mediators is discussed.
Collapse
|
209
|
Xu MJ, Cai Y, Wang H, Altamirano J, Chang B, Bertola A, Odena G, Lu J, Tanaka N, Matsusue K, Matsubara T, Mukhopadhyay P, Kimura S, Pacher P, Gonzalez FJ, Bataller R, Gao B. Fat-Specific Protein 27/CIDEC Promotes Development of Alcoholic Steatohepatitis in Mice and Humans. Gastroenterology 2015; 149:1030-41.e6. [PMID: 26099526 PMCID: PMC4584194 DOI: 10.1053/j.gastro.2015.06.009] [Citation(s) in RCA: 109] [Impact Index Per Article: 12.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/04/2014] [Revised: 05/29/2015] [Accepted: 06/09/2015] [Indexed: 12/13/2022]
Abstract
BACKGROUND & AIMS Alcoholic steatohepatitis (ASH) is the progressive form of alcoholic liver disease and may lead to cirrhosis and hepatocellular carcinoma. We studied mouse models and human tissues to identify molecules associated with ASH progression and focused on the mouse fat-specific protein 27 (FSP-27)/human cell death-inducing DFF45-like effector C (CIDEC) protein, which is expressed in white adipose tissues and promotes formation of fat droplets. METHODS C57BL/6N mice or mice with hepatocyte-specific disruption of Fsp27 (Fsp27(Hep-/-) mice) were fed the Lieber-Decarli ethanol liquid diet (5% ethanol) for 10 days to 12 weeks, followed by 1 or multiple binges of ethanol (5 or 6 g/kg) during the chronic feeding. Some mice were given an inhibitor (GW9662) of peroxisome proliferator-activated receptor γ (PPARG). Adenoviral vectors were used to express transgenes or small hairpin (sh) RNAs in cultured hepatocytes and in mice. Liver tissue samples were collected from ethanol-fed mice or from 31 patients with alcoholic hepatitis (AH) with biopsy-proved ASH and analyzed histologically and immunohistochemically and by transcriptome, immunoblotting, and real-time PCR analyses. RESULTS Chronic-plus-binge ethanol feeding of mice, which mimics the drinking pattern of patients with AH, produced severe ASH and mild fibrosis. Microarray analyses revealed similar alterations in expression of many hepatic genes in ethanol-fed mice and humans with ASH, including up-regulation of mouse Fsp27 (also called Cidec) and human CIDEC. Fsp27(Hep-/-) mice and mice given injections of adenovirus-Fsp27shRNA had markedly reduced ASH following chronic-plus-binge ethanol feeding. Inhibition of PPARG and cyclic AMP-responsive element binding protein H (CREBH) prevented the increases in Fsp27α and FSP27β mRNAs, respectively, and reduced liver injury in this chronic-plus-binge ethanol feeding model. Overexpression of FSP27 and ethanol exposure had synergistic effects in inducing production of mitochondrial reactive oxygen species and damage to hepatocytes in mice. Hepatic CIDEC mRNA expression was increased in patients with AH and correlated with the degree of hepatic steatosis and disease severity including mortality. CONCLUSIONS In mice, chronic-plus-binge ethanol feeding induces ASH that mimics some histological and molecular features observed in patients with AH. Hepatic expression of FSP27/CIDEC is highly up-regulated in mice following chronic-plus-binge ethanol feeding and in patients with AH; this up-regulation contributes to alcohol-induced liver damage.
Collapse
Affiliation(s)
- Ming-Jiang Xu
- Laboratory of Liver Diseases, National Institute on Alcohol Abuse and Alcoholism, National Institutes of Health, Bethesda, Maryland; Department of Physiology and Pathophysiology, School of Basic Medical Science, Peking University, Beijing, China
| | - Yan Cai
- Laboratory of Liver Diseases, National Institute on Alcohol Abuse and Alcoholism, National Institutes of Health, Bethesda, Maryland; Laboratory of Metabolism, National Cancer Institute, National Institutes of Health, Bethesda, Maryland
| | - Hua Wang
- Laboratory of Liver Diseases, National Institute on Alcohol Abuse and Alcoholism, National Institutes of Health, Bethesda, Maryland; Department of Oncology, The First Affiliated Hospital of Anhui Medical University, Hefei, China
| | - José Altamirano
- Institut d'Investigacions Biomèdiques August Pi i Sunyer (IDIBAPS) and Liver Unit-Internal Medicine Department, Vall d'Hebron Hospital, Vall d'Hebron Institut de Recerca, Barcelona, Spain
| | - Binxia Chang
- Laboratory of Liver Diseases, National Institute on Alcohol Abuse and Alcoholism, National Institutes of Health, Bethesda, Maryland
| | - Adeline Bertola
- Laboratory of Liver Diseases, National Institute on Alcohol Abuse and Alcoholism, National Institutes of Health, Bethesda, Maryland
| | - Gemma Odena
- Department of Nutrition, Gillings School of Global Public Health, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina
| | - Jim Lu
- GoPath Diagnostics, LLC, Chicago, Illinois
| | - Naoki Tanaka
- Laboratory of Metabolism, National Cancer Institute, National Institutes of Health, Bethesda, Maryland
| | - Kimihiko Matsusue
- Faculty of Pharmaceutical Science, Fukuoka University, Fukuoka, Japan
| | - Tsutomu Matsubara
- Laboratory of Metabolism, National Cancer Institute, National Institutes of Health, Bethesda, Maryland
| | - Partha Mukhopadhyay
- Section of Oxidative Stress and Tissue Injury, Laboratory of Physiological Studies, National Institute on Alcohol Abuse and Alcoholism, National Institutes of Health, Bethesda, Maryland
| | - Shioko Kimura
- Laboratory of Metabolism, National Cancer Institute, National Institutes of Health, Bethesda, Maryland
| | - Pal Pacher
- Section of Oxidative Stress and Tissue Injury, Laboratory of Physiological Studies, National Institute on Alcohol Abuse and Alcoholism, National Institutes of Health, Bethesda, Maryland
| | - Frank J Gonzalez
- Laboratory of Metabolism, National Cancer Institute, National Institutes of Health, Bethesda, Maryland
| | - Ramon Bataller
- Institut d'Investigacions Biomèdiques August Pi i Sunyer (IDIBAPS) and Liver Unit-Internal Medicine Department, Vall d'Hebron Hospital, Vall d'Hebron Institut de Recerca, Barcelona, Spain; Department of Nutrition, Gillings School of Global Public Health, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina; Department of Medicine, Division of Gastroenterology and Hepatology, University of North Carolina, Chapel Hill, North Carolina
| | - Bin Gao
- Laboratory of Liver Diseases, National Institute on Alcohol Abuse and Alcoholism, National Institutes of Health, Bethesda, Maryland.
| |
Collapse
|
210
|
Kim HY, Park SY, Lee MH, Rho JH, Oh YJ, Jung HU, Yoo SH, Jeong NY, Lee HJ, Suh S, Seo SY, Cheong J, Jeong JS, Yoo YH. Hepatic STAMP2 alleviates high fat diet-induced hepatic steatosis and insulin resistance. J Hepatol 2015; 63:477-85. [PMID: 25646886 DOI: 10.1016/j.jhep.2015.01.025] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/05/2014] [Revised: 01/14/2015] [Accepted: 01/18/2015] [Indexed: 12/24/2022]
Abstract
BACKGROUND & AIMS Most studies on the role of STAMP2 in metabolism have used adipose tissue. Little knowledge exists concerning the role of STAMP2 in the liver, which is a metabolically central target. We hypothesized that STAMP2 is involved in non-alcoholic fatty liver disease (NAFLD) pathogenesis. METHODS We examined our hypothesis using human NAFLD patient pathology samples and a high-fat diet (HFD)-induced NAFLD mouse model. The molecular mechanism underlying hepatic STAMP2-mediated lipid imbalance was explored using an oleic acid (OA)-induced NAFLD in vitro model. RESULTS Noticeably, the expression level of STAMP2 protein was reduced in the livers obtained from NAFLD patients and HFD-induced NAFLD mice. In vivo knockdown of hepatic STAMP2 by siRNA accelerated hepatic steatosis and insulin resistance in mice fed a HFD. Conversely, the delivery of adenoviral STAMP2 (Ad-STAMP2) improved hepatic steatosis in HFD-induced NAFLD mice. The expression of lipogenic or adipogenic factors was increased in both in vitro and in vivo NAFLD models but was reversed by Ad-STAMP2. Adenoviral overexpression of STAMP2 improved insulin resistance in the HFD-induced NAFLD mice. In vivo and in vitro assays demonstrated that STAMP2 modulates insulin sensitivity and glucose metabolism and that STAMP2 counteracts OA-induced insulin resistance by modulating insulin receptor substrate-1 stability. CONCLUSIONS The present study revealed that hepatic STAMP2 plays a pivotal role in preventing HFD-induced NAFLD and that STAMP2 overexpression improves hepatic steatosis and insulin resistance in NAFLD. Our findings indicate that STAMP2 may represent a suitable target for interventions targeting NAFLD.
Collapse
Affiliation(s)
- Hye Y Kim
- Dong-A University College of Medicine and Mitochondria Hub Regulation Center, Busan 602-714, South Korea
| | - So Y Park
- Dong-A University College of Medicine and Mitochondria Hub Regulation Center, Busan 602-714, South Korea
| | - Mi H Lee
- Dong-A University College of Medicine and Mitochondria Hub Regulation Center, Busan 602-714, South Korea
| | - Jee H Rho
- Dong-A University College of Medicine and Mitochondria Hub Regulation Center, Busan 602-714, South Korea
| | - Yoo J Oh
- Dong-A University College of Medicine and Mitochondria Hub Regulation Center, Busan 602-714, South Korea
| | - Hye U Jung
- Dong-A University College of Medicine and Mitochondria Hub Regulation Center, Busan 602-714, South Korea
| | - Seung H Yoo
- Dong-A University College of Medicine and Mitochondria Hub Regulation Center, Busan 602-714, South Korea
| | - Na Y Jeong
- Dong-A University College of Medicine and Mitochondria Hub Regulation Center, Busan 602-714, South Korea
| | - Hye J Lee
- Dong-A University College of Medicine and Mitochondria Hub Regulation Center, Busan 602-714, South Korea
| | - SungHwan Suh
- Department of Endocrinology, Dong-A University College of Medicine, Busan 602-714, South Korea
| | - Su Y Seo
- Department of Microbiology, Dong-A University College of Medicine, Busan 602-714, South Korea
| | - JaeHun Cheong
- Department of Molecular Biology, College of Natural Sciences, Pusan National University, Busan 609-735, South Korea
| | - Jin S Jeong
- Department of Pathology, Dong-A University College of Medicine, Busan 602-714, South Korea
| | - Young H Yoo
- Dong-A University College of Medicine and Mitochondria Hub Regulation Center, Busan 602-714, South Korea.
| |
Collapse
|
211
|
Choi SS, Park J, Choi JH. Revisiting PPARγ as a target for the treatment of metabolic disorders. BMB Rep 2015; 47:599-608. [PMID: 25154720 PMCID: PMC4281338 DOI: 10.5483/bmbrep.2014.47.11.174] [Citation(s) in RCA: 78] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2014] [Indexed: 02/03/2023] Open
Abstract
As the prevalence of obesity has increased explosively over the last several decades, associated metabolic disorders, including type 2 diabetes, dyslipidemia, hypertension, and cardiovascular diseases, have been also increased. Thus, new strategies for preventing and treating them are needed. The nuclear peroxisome proliferator-activated receptors (PPARs) are involved fundamentally in regulating energy homeostasis; thus, they have been considered attractive drug targets for addressing metabolic disorders. Among the PPARs, PPARγ is a master regulator of gene expression for metabolism, inflammation, and other pathways in many cell types, especially adipocytes. It is a physiological receptor of the
potent anti-diabetic drugs of the thiazolidinediones (TZDs) class, including rosiglitazone (Avandia). However, TZDs have undesirable and severe side effects, such as weight gain, fluid
retention, and cardiovascular dysfunction. Recently, many reports have suggested that PPARγ could be modulated by post-translational modifications (PTMs), and modulation of
PTM has been considered as novel approaches for treating metabolic disorders with fewer side effects than the TZDs. In this review, we discuss how PTM of PPARγ may be regulated and issues to be considered in making novel anti-diabetic drugs that can modulate the PTM of PPARγ. [BMB Reports 2014; 47(11): 599-608]
Collapse
Affiliation(s)
- Sun-Sil Choi
- Department of Biological Science, School of Life Sciences, Ulsan National Institute of Science and Technology (UNIST), Ulsan 689-798, Korea
| | - Jiyoung Park
- Department of Biological Science, School of Life Sciences, Ulsan National Institute of Science and Technology (UNIST), Ulsan 689-798, Korea
| | - Jang Hyun Choi
- Department of Biological Science, School of Life Sciences, Ulsan National Institute of Science and Technology (UNIST), Ulsan 689-798, Korea
| |
Collapse
|
212
|
Prosteatotic genes are associated with unsaturated fat suppression of saturated fat-induced hepatic steatosis in C57BL/6 mice. Nutr Res 2015; 35:812-22. [PMID: 26277244 DOI: 10.1016/j.nutres.2015.06.012] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2015] [Revised: 06/21/2015] [Accepted: 06/30/2015] [Indexed: 01/01/2023]
Abstract
Both high sugar and fat diets can induce prosteatotic genes, leading to obesity and obesity-associated diseases, including hepatic steatosis. Unsaturated fat/fatty acid (USFA) reduces high sugar-induced hepatic steatosis by inhibiting the induced prosteatotic genes. In contrast, it is still unclear how USFA ameliorates saturated fat/fatty acid (SFA)-induced hepatic steatosis. As sugar and fat have different transport and metabolic pathways, we hypothesized that USFA suppressed SFA-induced hepatic steatosis via a different set of prosteatotic genes. To test this, we implemented high SFA vs USFA diets and a control diet in C57BL/6 mice for 16 weeks. Severe hepatic steatosis was induced in mice fed the SFA diet. Among a nearly complete set of prosteatotic genes, only the stearoyl-coenzyme a desaturase 1 (Scd1), cluster of differentiation 36 (Cd36), and peroxisome proliferator-activated receptor γ (Pparγ) genes that were differentially expressed in the liver could contribute to SFA-induced steatosis or the alleviative effect of USFA. That is, the SFA diet induced the expression of Cd36 and Pparγ but not Scd1, and the USFA diet suppressed Scd1 expression and the induction of Cd36 and Pparγ. These findings were mainly recapitulated in cultured hepatocytes. The essential roles of SCD1 and CD36 were confirmed by the observation that the suppression of SCD1 and CD36 with small interfering RNA or drug treatment ameliorated SFA-induced lipid accumulation in hepatocytes. We thus concluded that SCD1, CD36, and PPARγ were essential to the suppression of SFA-induced hepatic steatosis by main dietary USFA, which may provide different therapeutic targets for reducing high-fat vs sugar-induced hepatic steatosis.
Collapse
|
213
|
Tsukamoto H. Metabolic reprogramming and cell fate regulation in alcoholic liver disease. Pancreatology 2015; 15:S61-5. [PMID: 25800177 PMCID: PMC4515387 DOI: 10.1016/j.pan.2015.03.003] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/29/2015] [Revised: 02/27/2015] [Accepted: 03/02/2015] [Indexed: 12/11/2022]
Abstract
UNLABELLED Alcoholic liver disease (ALD) should be defined as a life-style metabolic disease. Its pathogenesis is driven by altered cell fate of both parenchymal and non-parenchymal liver cell types, contributing to different pathologic spectra. A critical turning point in progression of ALD is chronic alcoholic steatohepatitis (ASH) or alcoholic neutrophilic hepatitis (AH), which markedly predisposes patients to most devastating ALD sequela, cirrhosis and liver cancer. RESULTS Our research identifies the pivotal roles of unique metabolic reprogramming in M1 activation of hepatic macrophages (HM) and myofibroblastic activation (MF) of hepatic stellate cells (HSC) in the genesis of inflammation and fibrosis, the two key histological features of chronic ASH and neutrophilic AH. For M1 HM activation, heightened proinflammatory iron redox signaling in endosomes or caveosomes results from altered iron metabolism and storage, promoting IKK/NF-kB activation via interactive activation of p21ras, TAK1, and PI3K. For MF cell fate regulation of HSC, activation of the morphogen Wnt pathway caused by the nuclear protein NECDIN or the single-pass trans-membrane protein DLK1, reprograms lipid metabolism via MeCP2-mediated epigenetic repression of the key HSC quiescence gene Ppar-γ. CONCLUSIONS The findings from these studies re-enforce the importance of metabolic reprogramming in cell fate regulation required for the pathogenesis of ALD.
Collapse
Affiliation(s)
- Hidekazu Tsukamoto
- Southern California Research Center ALPD and Cirrhosis and Department of Pathology, Keck School of Medicine of the University of Southern California, Greater Los Angeles VA Healthcare System, Los Angeles, California, USA
| |
Collapse
|
214
|
Steneberg P, Sykaras AG, Backlund F, Straseviciene J, Söderström I, Edlund H. Hyperinsulinemia Enhances Hepatic Expression of the Fatty Acid Transporter Cd36 and Provokes Hepatosteatosis and Hepatic Insulin Resistance. J Biol Chem 2015; 290:19034-43. [PMID: 26085100 PMCID: PMC4521028 DOI: 10.1074/jbc.m115.640292] [Citation(s) in RCA: 58] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2015] [Indexed: 01/01/2023] Open
Abstract
Hepatosteatosis is associated with the development of both hepatic insulin resistance and Type 2 diabetes. Hepatic expression of Cd36, a fatty acid transporter, is enhanced in obese and diabetic murine models and human nonalcoholic fatty liver disease, and thus it correlates with hyperinsulinemia, steatosis, and insulin resistance. Here, we have explored the effect of hyperinsulinemia on hepatic Cd36 expression, development of hepatosteatosis, insulin resistance, and dysglycemia. A 3-week sucrose-enriched diet was sufficient to provoke hyperinsulinemia, hepatosteatosis, hepatic insulin resistance, and dysglycemia in CBA/J mice. The development of hepatic steatosis and insulin resistance in CBA/J mice on a sucrose-enriched diet was paralleled by increased hepatic expression of the transcription factor Pparγ and its target gene Cd36 whereas that of genes implicated in lipogenesis, fatty acid oxidation, and VLDL secretion was unaltered. Additionally, we demonstrate that insulin, in a Pparγ-dependent manner, is sufficient to directly increase Cd36 expression in perfused livers and isolated hepatocytes. Mouse strains that display low insulin levels, i.e. C57BL6/J, and/or lack hepatic Pparγ, i.e. C3H/HeN, do not develop hepatic steatosis, insulin resistance, or dysglycemia on a sucrose-enriched diet, suggesting that elevated insulin levels, via enhanced CD36 expression, provoke fatty liver development that in turn leads to hepatic insulin resistance and dysglycemia. Thus, our data provide evidence for a direct role for hyperinsulinemia in stimulating hepatic Cd36 expression and thus the development of hepatosteatosis, hepatic insulin resistance, and dysglycemia.
Collapse
Affiliation(s)
| | | | | | | | - Ingegerd Söderström
- the Department of Public Health and Clinical Medicine, Umeå University, SE-901 87 Umeå, Sweden
| | | |
Collapse
|
215
|
Labrie M, Lalonde S, Najyb O, Thiery M, Daneault C, Des Rosiers C, Rassart E, Mounier C. Apolipoprotein D Transgenic Mice Develop Hepatic Steatosis through Activation of PPARγ and Fatty Acid Uptake. PLoS One 2015; 10:e0130230. [PMID: 26083030 PMCID: PMC4470830 DOI: 10.1371/journal.pone.0130230] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2014] [Accepted: 05/18/2015] [Indexed: 12/27/2022] Open
Abstract
Transgenic mice (Tg) overexpressing human apolipoprotein D (H-apoD) in the brain are resistant to neurodegeneration. Despite the use of a neuron-specific promoter to generate the Tg mice, they expressed significant levels of H-apoD in both plasma and liver and they slowly develop hepatic steatosis and insulin resistance. We show here that hepatic PPARγ expression in Tg mice is increased by 2-fold compared to wild type (WT) mice. Consequently, PPARγ target genes Plin2 and Cide A/C are overexpressed, leading to increased lipid droplets formation. Expression of the fatty acid transporter CD36, another PPARgamma target, is also increased in Tg mice associated with elevated fatty acid uptake as measured in primary hepatocytes. Elevated expression of AMPK in the liver of Tg leads to phosphorylation of acetyl CoA carboxylase, indicating a decreased activity of the enzyme. Fatty acid synthase expression is also induced but the hepatic lipogenesis measured in vivo is not significantly different between WT and Tg mice. In addition, expression of carnitine palmitoyl transferase 1, the rate-limiting enzyme of beta-oxidation, is slightly upregulated. Finally, we show that overexpressing H-apoD in HepG2 cells in presence of arachidonic acid (AA), the main apoD ligand, increases the transcriptional activity of PPARγ. Supporting the role of apoD in AA transport, we observed enrichment in hepatic AA and a decrease in plasmatic AA concentration. Taken together, our results demonstrate that the hepatic steatosis observed in apoD Tg mice is a consequence of increased PPARγ transcriptional activity by AA leading to increased fatty acid uptake by the liver.
Collapse
Affiliation(s)
- Marilyne Labrie
- Centre de recherche BioMed, Département des Sciences Biologiques, Université du Québec, Montréal, Québec, H3C 3P8, Canada
| | - Simon Lalonde
- Centre de recherche BioMed, Département des Sciences Biologiques, Université du Québec, Montréal, Québec, H3C 3P8, Canada
| | - Ouafa Najyb
- Centre de recherche BioMed, Département des Sciences Biologiques, Université du Québec, Montréal, Québec, H3C 3P8, Canada
| | - Maxime Thiery
- Centre de recherche BioMed, Département des Sciences Biologiques, Université du Québec, Montréal, Québec, H3C 3P8, Canada
| | - Caroline Daneault
- Montreal Heart Institute Research Center, Montreal, Quebec, H1T 1C8,Canada
| | - Chrisitne Des Rosiers
- Department of Nutrition, Université de Montréal, Montréal, Québec, H3C 3J7,Canada
- Montreal Heart Institute Research Center, Montreal, Quebec, H1T 1C8,Canada
| | - Eric Rassart
- Centre de recherche BioMed, Département des Sciences Biologiques, Université du Québec, Montréal, Québec, H3C 3P8, Canada
| | - Catherine Mounier
- Centre de recherche BioMed, Département des Sciences Biologiques, Université du Québec, Montréal, Québec, H3C 3P8, Canada
- * E-mail:
| |
Collapse
|
216
|
Tseng HT, Park YJ, Lee YK, Moore DD. The orphan nuclear receptor small heterodimer partner is required for thiazolidinedione effects in leptin-deficient mice. J Biomed Sci 2015; 22:30. [PMID: 25951943 PMCID: PMC4489392 DOI: 10.1186/s12929-015-0133-3] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2015] [Accepted: 03/30/2015] [Indexed: 01/09/2023] Open
Abstract
BACKGROUND Small heterodimer partner (SHP, NR0B2) is involved in diverse metabolic pathways, including hepatic bile acid, lipid and glucose homeostasis, and has been implicated in effects on the peroxisome proliferator-activated receptor γ (PPARγ), a master regulator of adipogenesis and the receptor for antidiabetic drugs thiazolidinediones (TZDs). In this study, we aim to investigate the role of SHP in TZD response by comparing TZD-treated leptin-deficient (ob/ob) and leptin-, SHP-deficient (ob/ob;Shp(-/-)) double mutant mice. RESULTS Both ob/ob and double mutant ob/ob;Shp(-/-) mice developed hyperglycemia, insulin resistance, and hyperlipidemia, but hepatic fat accumulation was decreased in the double mutant ob/ob;Shp(-/-) mice. PPARγ2 mRNA levels were markedly lower in ob/ob;Shp(-/-) liver and decreased to a lesser extent in adipose tissue. The TZD troglitazone did not reduce glucose or circulating triglyceride levels in ob/ob;Shp(-/-) mice. Expression of the adipocytokines, such as adiponectin and resistin, was not stimulated by troglitazone treatment. Expression of hepatic lipogenic genes was also reduced in ob/ob;Shp(-/-) mice. Moreover, overexpression of SHP by adenovirus infection increased PPARγ2 mRNA levels in mouse primary hepatocytes. CONCLUSIONS Our results suggest that SHP is required for both antidiabetic and hypolipidemic effects of TZDs in ob/ob mice through regulation of PPARγ expression.
Collapse
Affiliation(s)
- Hsiu-Ting Tseng
- Department of Molecular and Cellular Biology, Baylor College of Medicine, One Baylor Plaza, Houston, Texas, USA.
| | - Young Joo Park
- 300 Gumi-dong, Bundang-gu, Department of Internal Medicine, Seoul National University Bundang Hospital, Seongnam-si, Kyeonggi-do, South Korea.
| | - Yoon Kwang Lee
- Department of Integrative Medical Sciences, Northeast Ohio Medical University, Rootstown, OH, USA.
| | - David D Moore
- Department of Molecular and Cellular Biology, Baylor College of Medicine, One Baylor Plaza, Houston, Texas, USA.
| |
Collapse
|
217
|
Interleukin-6 gene transfer reverses body weight gain and fatty liver in obese mice. Biochim Biophys Acta Mol Basis Dis 2015; 1852:1001-11. [DOI: 10.1016/j.bbadis.2015.01.017] [Citation(s) in RCA: 65] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2014] [Revised: 01/16/2015] [Accepted: 01/21/2015] [Indexed: 01/30/2023]
|
218
|
Yu JH, Lee YJ, Kim HJ, Choi H, Choi Y, Seok JW, Kim JW. Monoacylglycerol O-acyltransferase 1 is regulated by peroxisome proliferator-activated receptor γ in human hepatocytes and increases lipid accumulation. Biochem Biophys Res Commun 2015; 460:715-20. [PMID: 25838202 DOI: 10.1016/j.bbrc.2015.03.095] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2015] [Accepted: 03/17/2015] [Indexed: 02/06/2023]
Abstract
Monoacylglycerol O-acyltransferase (MGAT) is an enzyme that is involved in triglyceride synthesis by catalyzing the formation of diacylglycerol from monoacylglycerol and fatty acyl CoAs. Recently, we reported that MGAT1 has a critical role in hepatic TG accumulation and that its suppression ameliorates hepatic steatosis in a mouse model. However, the function of MGAT enzymes in hepatic lipid accumulation has not been investigated in humans. Unlike in rodents, MGAT3 as well as MGAT1 and MGAT2 are present in humans. In this study, we evaluated the differences between MGAT subtypes and their association with peroxisome proliferator-activated receptor γ (PPARγ), a regulator of mouse MGAT1 expression. In human primary hepatocytes, basal expression of MGAT1 was lower than that of MGAT2 or MGAT3, but was strongly induced by PPARγ overexpression. A luciferase assay as well as an electromobility shift assay revealed that human MGAT1 promoter activity is driven by PPARγ by direct binding to at least two regions of the promoter in 293T and HepG2 cells. Moreover, siRNA-mediated suppression of MGAT1 expression significantly attenuated lipid accumulation by PPARγ overexpression in HepG2 cells, as evidenced by oil-red-O staining. These results suggest that human MGAT1 has an important role in fatty liver formation as a target gene of PPARγ, and blocking MGAT1 activity could be an efficient therapeutic way to reduce nonalcoholic fatty liver diseases in humans.
Collapse
Affiliation(s)
- Jung Hwan Yu
- Department of Biochemistry and Molecular Biology, Integrated Genomic Research Center for Metabolic Regulation, Institute of Genetic Science, Yonsei University College of Medicine, Seoul 120-752, Republic of Korea; Brain Korea 21 PLUS Project for Medical Science, Yonsei University, Seoul 120-752, Republic of Korea
| | - Yoo Jeong Lee
- Division of Metabolic Disease, Center for Biomedical Sciences, National Institutes of Health, Cheongwon-gun, Chungbuk 363-951, Republic of Korea
| | - Hyo Jung Kim
- Department of Biochemistry and Molecular Biology, Integrated Genomic Research Center for Metabolic Regulation, Institute of Genetic Science, Yonsei University College of Medicine, Seoul 120-752, Republic of Korea
| | - Hyeonjin Choi
- Department of Biochemistry and Molecular Biology, Integrated Genomic Research Center for Metabolic Regulation, Institute of Genetic Science, Yonsei University College of Medicine, Seoul 120-752, Republic of Korea
| | - Yoonjeong Choi
- Department of Biochemistry and Molecular Biology, Integrated Genomic Research Center for Metabolic Regulation, Institute of Genetic Science, Yonsei University College of Medicine, Seoul 120-752, Republic of Korea; Brain Korea 21 PLUS Project for Medical Science, Yonsei University, Seoul 120-752, Republic of Korea
| | - Jo Woon Seok
- Department of Biochemistry and Molecular Biology, Integrated Genomic Research Center for Metabolic Regulation, Institute of Genetic Science, Yonsei University College of Medicine, Seoul 120-752, Republic of Korea; Brain Korea 21 PLUS Project for Medical Science, Yonsei University, Seoul 120-752, Republic of Korea
| | - Jae-woo Kim
- Department of Biochemistry and Molecular Biology, Integrated Genomic Research Center for Metabolic Regulation, Institute of Genetic Science, Yonsei University College of Medicine, Seoul 120-752, Republic of Korea; Brain Korea 21 PLUS Project for Medical Science, Yonsei University, Seoul 120-752, Republic of Korea; Severance Biomedical Science Institute, Yonsei University College of Medicine, Seoul 120-752, Republic of Korea.
| |
Collapse
|
219
|
Reis SRDL, Feres NH, Ignacio-Souza LM, Veloso RV, Arantes VC, Kawashita NH, Colodel EM, Botosso BL, Reis MADB, Latorraca MQ. Nutritional recovery with a soybean diet after weaning reduces lipogenesis but induces inflammation in the liver in adult rats exposed to protein restriction during intrauterine life and lactation. Mediators Inflamm 2015; 2015:781703. [PMID: 25892856 PMCID: PMC4393912 DOI: 10.1155/2015/781703] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2014] [Revised: 10/23/2014] [Accepted: 11/18/2014] [Indexed: 02/07/2023] Open
Abstract
We evaluated the effects of postweaning nutritional recovery with a soybean flour diet on de novo hepatic lipogenesis and inflammation in adult rats exposed to protein restriction during intrauterine life and lactation. Rats from mothers fed with protein (casein) in a percentage of 17% (control, C) or 6% (low, L) during pregnancy and lactation were fed with diet that contained 17% casein (CC and LC groups, resp.) or soybean (CS and LS groups, resp.) after weaning until 90 days of age. LS and CS rats had low body weight, normal basal serum triglyceride levels, increased ALT concentrations, and high HOMA-IR indices compared with LC and CC rats. The soybean diet reduced PPARγ as well as malic enzyme and citrate lyase contents and activities. The lipogenesis rate and liver fat content were lower in LS and CS rats relative to LC and CC rats. TNFα mRNA and protein levels were higher in LS and CS rats than in LC and CC rats. NF-κB mRNA levels were lower in the LC and LS groups compared with the CC and LC groups. Thus, the soybean diet prevented hepatic steatosis at least in part through reduced lipogenesis but resulted in TNFα-mediated inflammation.
Collapse
Affiliation(s)
- Sílvia Regina de Lima Reis
- Departamento de Alimentos e Nutrição, Faculdade de Nutrição, Universidade Federal de Mato Grosso (UFMT), 78060-900 Cuiabá, MT, Brazil
| | - Naoel Hassan Feres
- Departamento de Alimentos e Nutrição, Faculdade de Nutrição, Universidade Federal de Mato Grosso (UFMT), 78060-900 Cuiabá, MT, Brazil
| | - Leticia Martins Ignacio-Souza
- Departamento de Alimentos e Nutrição, Faculdade de Nutrição, Universidade Federal de Mato Grosso (UFMT), 78060-900 Cuiabá, MT, Brazil
| | - Roberto Vilela Veloso
- Departamento de Alimentos e Nutrição, Faculdade de Nutrição, Universidade Federal de Mato Grosso (UFMT), 78060-900 Cuiabá, MT, Brazil
| | - Vanessa Cristina Arantes
- Departamento de Alimentos e Nutrição, Faculdade de Nutrição, Universidade Federal de Mato Grosso (UFMT), 78060-900 Cuiabá, MT, Brazil
| | - Nair Honda Kawashita
- Departamento de Química, Instituto de Ciências Exatas e da Terra, Universidade Federal de Mato Grosso (UFMT), 78060-900 Cuiabá, MT, Brazil
| | - Edson Moleta Colodel
- Departamento de Clínica Médica Veterinária, Faculdade de Agronomia e Medicina Veterinária, Universidade Federal de Mato Grosso (UFMT), 78060-900 Cuiabá, MT, Brazil
| | - Bárbara Laet Botosso
- Departamento de Alimentos e Nutrição, Faculdade de Nutrição, Universidade Federal de Mato Grosso (UFMT), 78060-900 Cuiabá, MT, Brazil
| | - Marise Auxiliadora de Barros Reis
- Departamento de Alimentos e Nutrição, Faculdade de Nutrição, Universidade Federal de Mato Grosso (UFMT), 78060-900 Cuiabá, MT, Brazil
| | - Márcia Queiroz Latorraca
- Departamento de Alimentos e Nutrição, Faculdade de Nutrição, Universidade Federal de Mato Grosso (UFMT), 78060-900 Cuiabá, MT, Brazil
| |
Collapse
|
220
|
Wu C, Jia Y, Lee JH, Kim Y, Sekharan S, Batista VS, Lee SJ. Activation of OR1A1 suppresses PPAR-γ expression by inducing HES-1 in cultured hepatocytes. Int J Biochem Cell Biol 2015; 64:75-80. [PMID: 25817041 DOI: 10.1016/j.biocel.2015.03.008] [Citation(s) in RCA: 36] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2014] [Revised: 02/15/2015] [Accepted: 03/09/2015] [Indexed: 12/17/2022]
Abstract
Olfactory receptors (ORs) comprise the largest G protein-coupled receptor gene superfamily. Recent studies indicate that ORs are also expressed in non-olfactory organs, including metabolically active tissues, although their biological functions in these tissues are largely unknown. In this study, OR1A1 expression was detected in HepG2 liver cells. OR1A1 activation by (-)-carvone, a known OR1A1 ligand, increased the cyclic adenosine monophosphate (cAMP), but not intracellular Ca(2+) concentration, thereby inducing protein kinase A (PKA) activity with subsequent phosphorylation of cAMP response element-binding protein (CREB) and upregulation of the CREB-responsive gene hairy and enhancer of split (HES)-1, a corepressor of peroxisome proliferator-activated receptor-γ (PPAR-γ) in hepatocytes. In (-)-carvone-stimulated cells, the repression of PPAR-γ reduced the expression of the target gene, mitochondrial glycerol-3-phosphate acyltransferase, which encodes a key enzyme involved in triglyceride synthesis. Intracellular triglyceride level and lipid accumulation were reduced in cells stimulated with (-)-carvone, effects that were diminished following the loss of OR1A1 function. These results indicate that OR1A1 may function as a non-redundant receptor in hepatocytes that regulates the PKA-CREB-HES-1 signaling axis and thereby modulates hepatic triglyceride metabolism.
Collapse
Affiliation(s)
- Chunyan Wu
- Department of Biotechnology, Graduate School of Life Sciences and Biotechnology, BK21-PLUS, Korea University, Seoul 136-713, Republic of Korea
| | - Yaoyao Jia
- Department of Biotechnology, Graduate School of Life Sciences and Biotechnology, BK21-PLUS, Korea University, Seoul 136-713, Republic of Korea
| | - Ji Hae Lee
- Department of Biotechnology, Graduate School of Life Sciences and Biotechnology, BK21-PLUS, Korea University, Seoul 136-713, Republic of Korea
| | - Yeonji Kim
- Department of Biotechnology, Graduate School of Life Sciences and Biotechnology, BK21-PLUS, Korea University, Seoul 136-713, Republic of Korea
| | - Sivakumar Sekharan
- Department of Chemistry, Yale University, New Haven, CT 06520, United States
| | - Victor S Batista
- Department of Chemistry, Yale University, New Haven, CT 06520, United States
| | - Sung-Joon Lee
- Department of Biotechnology, Graduate School of Life Sciences and Biotechnology, BK21-PLUS, Korea University, Seoul 136-713, Republic of Korea.
| |
Collapse
|
221
|
Lee DH, Hong JE, Yun HM, Hwang CJ, Park JH, Han SB, Yoon DY, Song MJ, Hong JT. Interleukin-32β ameliorates metabolic disorder and liver damage in mice fed high-fat diet. Obesity (Silver Spring) 2015; 23:615-22. [PMID: 25645248 DOI: 10.1002/oby.21001] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/01/2014] [Accepted: 11/19/2014] [Indexed: 12/19/2022]
Abstract
OBJECTIVE Chronic excessive food intake leads to energy imbalance, resulting in hepatic steatosis and inflammation. Interleukin-32 (IL-32) is known to be a pro-inflammatory cytokine associated with chronic inflammation and cancer. Therefore, the relationship between IL-32 and chronic excessive food intake-induced liver disease was investigated. METHODS Male IL-32β transgenic and wild-type mice were fed a high-fat diet (HFD) for 15 weeks. They were compared with wild-type mice on a standard chow diet. Daily food intake, body and liver weight, serum biochemistry, histopathological analysis of the liver, and hepatic immune response were determined. RESULTS IL-32β mice on HFD showed lower lipid accumulation, reduced infiltration of immune cells, and lower production of pro-inflammatory cytokines in the liver. The expression of the peroxisome proliferator-activated receptor γ (PPARγ) was downregulated and the adenosine 50-monophosphate (AMP)-activated protein kinase (AMPK) was activated in the liver of IL-32β mice compared to wild-type mice. Furthermore, IL-32β over-expression activated the AMPK pathway and IL-32β downregulation inactivated the AMPK pathway in HepG2 cells under high-glucose conditions. CONCLUSIONS These data suggest that IL-32β modulates lipid accumulation through inhibition of PPARγ expression and AMPK activation.
Collapse
Affiliation(s)
- Dong Hun Lee
- College of Pharmacy, Chungbuk National University, Heungduk-gu, Cheongju, Chungbuk, Republic of Korea
| | | | | | | | | | | | | | | | | |
Collapse
|
222
|
Maternal restraint stress during pregnancy in mice induces 11β-HSD1-associated metabolic changes in the livers of the offspring. J Dev Orig Health Dis 2015; 6:105-14. [DOI: 10.1017/s2040174415000100] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
Abstract
In rats, maternal exposure to restraint stress during pregnancy can induce abnormalities in the cardiovascular and central nervous systems of the offspring. These effects are mediated by long-lasting hyperactivation of the hypothalamic–pituitary–adrenal axis. However, little is known about the potential effects of stress during pregnancy on metabolic systems. We examined the effect of restraint stress in pregnant mice on the liver function of their offspring. The offspring of stressed mothers showed significantly higher lipid accumulation in the liver after weaning than did the controls; this accumulation was associated with increased expression of lipid metabolism-related proteins such as alanine aminotransferase 2 diglyceride acyltransferase 1, peroxisome proliferator-activated receptor gamma and glucocorticoid receptor. Additionally, we observed increased levels of 11β-hydroxysteroid dehydrogenase type 1, an intercellular mediator that converts glucocorticoid from the inactive to the active form, in the foetal and postnatal periods. These results indicate that restraint stress in pregnancy in mice induces metabolic abnormalities via 11β-hydroxysteroid dehydrogenase type 1-related pathways in the foetal liver. It is therefore possible that exposure to stress in pregnant women may be a risk factor for metabolic syndromes (e.g. fatty liver) in children.
Collapse
|
223
|
Nagaya T, Tanaka N, Kimura T, Kitabatake H, Fujimori N, Komatsu M, Horiuchi A, Yamaura T, Umemura T, Sano K, Gonzalez FJ, Aoyama T, Tanaka E. Mechanism of the development of nonalcoholic steatohepatitis after pancreaticoduodenectomy. BBA CLINICAL 2015; 3:168-74. [PMID: 26674248 PMCID: PMC4661550 DOI: 10.1016/j.bbacli.2015.02.001] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/13/2014] [Revised: 02/05/2015] [Accepted: 02/10/2015] [Indexed: 02/08/2023]
Abstract
Background and aim It is recognized that nonalcoholic fatty liver disease (NAFLD), including nonalcoholic steatohepatitis (NASH), may develop after pancreaticoduodenectomy (PD). However, the mechanism of NASH development remains unclear. This study aimed to examine the changes in gene expression associated with NASH occurrence following PD. Methods The expression of genes related to fatty acid/triglyceride (FA/TG) metabolism and inflammatory signaling was examined using liver samples obtained from 7 post-PD NASH patients and compared with 6 healthy individuals and 32 conventional NASH patients. Results The livers of post-PD NASH patients demonstrated significant up-regulation of the genes encoding CD36, FA-binding proteins 1 and 4, acetyl-coenzyme A carboxylase α, diacylglycerol acyltransferase 2, and peroxisome proliferator-activated receptor (PPAR) γ compared with normal and conventional NASH livers. Although serum apolipoprotein B (ApoB) and TG were decreased in post-PD NASH patients, the mRNAs of ApoB and microsomal TG transfer protein were robustly increased, indicating impaired TG export from the liver as very-low-density lipoprotein (VLDL). Additionally, elevated mRNA levels of myeloid differentiation primary response 88 and superoxide dismutases in post-PD NASH livers suggested significant activation of innate immune response and augmentation of oxidative stress generation. Conclusions Enhanced FA uptake into hepatocytes and lipogenesis, up-regulation of PPARγ, and disruption of VLDL excretion into the circulation are possible mechanisms of steatogenesis after PD. General significance These results provide a basis for understanding the pathogenesis of NAFLD/NASH following PD. The mechanism of NASH development after pancreaticoduodenectomy (PD) was unclear. The gene expression involved in fatty acid uptake and lipogenesis was increased. PPARγ and its target genes were up-regulated in post-PD NASH livers. Impaired triglyceride excretion from the liver was suggested in post-PD NASH. This study proposes possible mechanisms of steatogenesis after PD.
Collapse
Key Words
- ACACA, acetyl-CoA carboxylase α
- ACACB, acetyl-CoA carboxylase β
- ACADM, medium-chain acyl-CoA dehydrogenase
- ACOX1, acyl-CoA oxidase 1
- ALT, alanine aminotransferase
- AST, aspartate aminotransferase
- ApoB, apolipoprotein B
- BMI, body mass index
- CAT, catalase
- CPT1A, carnitine palmitoyl-CoA transferase 1α
- CT, computed tomography
- CYBB, cytochrome b-245 β polypeptide
- CYP, cytochrome P450
- CoA, coenzyme A
- DGAT, diacylglycerol acyltransferase
- FA, fatty acid
- FABP, fatty acid-binding protein
- FASN, fatty acid synthase
- Fatty acid
- HADHA, hydroxyacyl-CoA dehydrogenase/3-ketoacyl-CoA thiolase/enoyl-CoA hydratase α
- HBV, hepatitis B virus
- HCV, hepatitis C virus
- HOMA-IR, homeostasis model assessment for insulin resistance
- LPS, lipopolysaccharide
- LXR, liver X receptor
- MCD, methionine- and choline-deficient diet
- MTTP, microsomal triglyceride transfer protein
- MYD88, myeloid differentiation primary response 88
- MyD88
- NAFLD, nonalcoholic fatty liver disease
- NAS, NAFLD activity score
- NASH
- NASH, nonalcoholic steatohepatitis
- PD, pancreaticoduodenectomy
- PPAR, peroxisome proliferator-activated receptor
- PPARGC, PPARγ co-activator
- Pancreaticoduodenectomy
- ROS, reactive oxygen species
- RXR, retinoid X receptor
- SCD, stearoyl-CoA desaturase
- SOD, superoxide dismutase
- SREBF1, sterol regulatory element-binding transcription factor 1
- TG, triglyceride
- TGFB1, transforming growth factor β1
- TLR, Toll-like receptor
- TNF, tumor necrosis factor α
- US, ultrasonography
- VLDL
- VLDL, very-low-density lipoprotein
- qPCR, quantitative polymerase chain reaction
- γGT, gamma-glutamyltransferase
Collapse
Affiliation(s)
- Tadanobu Nagaya
- Department of Gastroenterology, Shinshu University School of Medicine, Matsumoto, Japan
| | - Naoki Tanaka
- Department of Gastroenterology, Shinshu University School of Medicine, Matsumoto, Japan ; Department of Metabolic Regulation, Shinshu University Graduate School of Medicine, Matsumoto, Japan
| | - Takefumi Kimura
- Department of Gastroenterology, Shinshu University School of Medicine, Matsumoto, Japan
| | - Hiroyuki Kitabatake
- Department of Gastroenterology, Shinshu University School of Medicine, Matsumoto, Japan
| | - Naoyuki Fujimori
- Department of Gastroenterology, Shinshu University School of Medicine, Matsumoto, Japan
| | - Michiharu Komatsu
- Department of Gastroenterology, Shinshu University School of Medicine, Matsumoto, Japan
| | - Akira Horiuchi
- Digestive Disease Center, Showa Inan General Hospital, Komagane, Japan
| | - Takahiro Yamaura
- Department of Gastroenterology, Iida Municipal Hospital, Iida, Japan
| | - Takeji Umemura
- Department of Gastroenterology, Shinshu University School of Medicine, Matsumoto, Japan
| | - Kenji Sano
- Department of Laboratory Medicine, Shinshu University Hospital, Matsumoto, Japan
| | - Frank J Gonzalez
- Laboratory of Metabolism, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Bethesda, MD 20892, United States
| | - Toshifumi Aoyama
- Department of Metabolic Regulation, Shinshu University Graduate School of Medicine, Matsumoto, Japan
| | - Eiji Tanaka
- Department of Gastroenterology, Shinshu University School of Medicine, Matsumoto, Japan
| |
Collapse
|
224
|
Fatty acid signaling: the new function of intracellular lipases. Int J Mol Sci 2015; 16:3831-55. [PMID: 25674855 PMCID: PMC4346929 DOI: 10.3390/ijms16023831] [Citation(s) in RCA: 94] [Impact Index Per Article: 10.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2014] [Revised: 11/19/2014] [Accepted: 01/21/2015] [Indexed: 12/21/2022] Open
Abstract
Until recently, intracellular triacylglycerols (TAG) stored in the form of cytoplasmic lipid droplets have been considered to be only passive “energy conserves”. Nevertheless, degradation of TAG gives rise to a pleiotropic spectrum of bioactive intermediates, which may function as potent co-factors of transcription factors or enzymes and contribute to the regulation of numerous cellular processes. From this point of view, the process of lipolysis not only provides energy-rich equivalents but also acquires a new regulatory function. In this review, we will concentrate on the role that fatty acids liberated from intracellular TAG stores play as signaling molecules. The first part provides an overview of the transcription factors, which are regulated by fatty acids derived from intracellular stores. The second part is devoted to the role of fatty acid signaling in different organs/tissues. The specific contribution of free fatty acids released by particular lipases, hormone-sensitive lipase, adipose triacylglycerol lipase and lysosomal lipase will also be discussed.
Collapse
|
225
|
The multifaceted factor peroxisome proliferator-activated receptor γ (PPARγ) in metabolism, immunity, and cancer. Arch Pharm Res 2015; 38:302-12. [DOI: 10.1007/s12272-015-0559-x] [Citation(s) in RCA: 45] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2014] [Accepted: 01/08/2015] [Indexed: 10/24/2022]
|
226
|
Deminice R, de Castro GSF, Francisco LV, da Silva LECM, Cardoso JFR, Frajacomo FTT, Teodoro BG, Dos Reis Silveira L, Jordao AA. Creatine supplementation prevents fatty liver in rats fed choline-deficient diet: a burden of one-carbon and fatty acid metabolism. J Nutr Biochem 2015; 26:391-7. [PMID: 25649792 DOI: 10.1016/j.jnutbio.2014.11.014] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2014] [Revised: 11/05/2014] [Accepted: 11/19/2014] [Indexed: 02/06/2023]
Abstract
AIM To examine the effects of creatine (Cr) supplementation on liver fat accumulation in rats fed a choline-deficient diet. METHODS Twenty-four rats were divided into 3 groups of 8 based on 4 weeks of feeding an AIN-93 control diet (C), a choline-deficient diet (CDD) or a CDD supplemented with 2% Cr. The CDD diet was AIN-93 without choline. RESULTS The CDD significantly increased plasma homocysteine and TNFα concentration, as well as ALT activity. In liver, the CDD enhanced concentrations of total fat (55%), cholesterol (25%), triglycerides (87%), MDA (30%), TNFα (241%) and decreased SAM concentrations (25%) and the SAM/SAH ratio (33%). Cr supplementation prevented all these metabolic changes, except for hepatic SAM and the SAM/SAH ratio. However, no changes in PEMT gene expression or liver phosphatidylcholine levels were observed among the three experimental groups, and there were no changes in hepatic triglyceride transfer protein (MTP) mRNA level. On the contrary, Cr supplementation normalized expression of the transcription factors PPARα and PPARγ that were altered by the CDD. Further, the downstream targets and fatty acids metabolism genes, UCP2, LCAD and CPT1a, were also normalized in the Cr group as compared to CDD-fed rats. CONCLUSION Cr supplementation prevented fat liver accumulation and hepatic injures in rats fed with a CDD for 4 weeks. Our results demonstrated that one-carbon metabolism may have a small role in mitigating hepatic fat accumulation by Cr supplementation. The modulation of key genes related to fatty acid oxidation pathway suggests a new mechanism by which Cr prevents liver fat accumulation.
Collapse
Affiliation(s)
- Rafael Deminice
- Nutrition and Metabolism, Faculty of Medicine of Ribeirao Preto, University of Sao Paulo, Av. Bandeirantes 3900, Ribeirao Preto, Sao Paulo, Brazil; Department of Physical Education, Faculty of Physical Education and Sport, State University of Londrina. Rodovia Celso Garcia Cid
- Pr 445 Km 380
- Campus Universitário, Londrina, Paraná, Brazil.
| | - Gabriela Salim Ferreira de Castro
- Nutrition and Metabolism, Faculty of Medicine of Ribeirao Preto, University of Sao Paulo, Av. Bandeirantes 3900, Ribeirao Preto, Sao Paulo, Brazil
| | - Lucas Vieira Francisco
- Nutrition and Metabolism, Faculty of Medicine of Ribeirao Preto, University of Sao Paulo, Av. Bandeirantes 3900, Ribeirao Preto, Sao Paulo, Brazil
| | - Lilian Eslaine Costa Mendes da Silva
- Nutrition and Metabolism, Faculty of Medicine of Ribeirao Preto, University of Sao Paulo, Av. Bandeirantes 3900, Ribeirao Preto, Sao Paulo, Brazil
| | - João Felipe Rito Cardoso
- Nutrition and Metabolism, Faculty of Medicine of Ribeirao Preto, University of Sao Paulo, Av. Bandeirantes 3900, Ribeirao Preto, Sao Paulo, Brazil
| | - Fernando Tadeu Trevisan Frajacomo
- Nutrition and Metabolism, Faculty of Medicine of Ribeirao Preto, University of Sao Paulo, Av. Bandeirantes 3900, Ribeirao Preto, Sao Paulo, Brazil
| | - Bruno Gonzaga Teodoro
- Department of Biochesmtry and Imunology, Faculty of Medicine of Ribeirão Preto Av. Bandeirantes 3900, Ribeirao Preto, Sao Paulo, Brazil
| | - Leonardo Dos Reis Silveira
- School of Physical Education of Ribeirao Preto, University of Sao Paulo, Av. Bandeirantes 3900, Ribeirao Preto, Sao Paulo, Brazil; Department of Biochesmtry and Imunology, Faculty of Medicine of Ribeirão Preto Av. Bandeirantes 3900, Ribeirao Preto, Sao Paulo, Brazil
| | - Alceu Afonso Jordao
- Nutrition and Metabolism, Faculty of Medicine of Ribeirao Preto, University of Sao Paulo, Av. Bandeirantes 3900, Ribeirao Preto, Sao Paulo, Brazil
| |
Collapse
|
227
|
Chou CF, Zhu X, Lin YY, Gamble KL, Garvey WT, Chen CY. KSRP is critical in governing hepatic lipid metabolism through controlling Per2 expression. J Lipid Res 2014; 56:227-40. [PMID: 25514904 DOI: 10.1194/jlr.m050724] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
Hepatic lipid metabolism is controlled by integrated metabolic pathways. Excess accumulation of hepatic TG is a hallmark of nonalcoholic fatty liver disease, which is associated with obesity and insulin resistance. Here, we show that KH-type splicing regulatory protein (KSRP) ablation reduces hepatic TG levels and diet-induced hepatosteatosis. Expression of period 2 (Per2) is increased during the dark period, and circadian oscillations of several core clock genes are altered with a delayed phase in Ksrp(-/-) livers. Diurnal expression of some lipid metabolism genes is also disturbed with reduced expression of genes involved in de novo lipogenesis. Using primary hepatocytes, we demonstrate that KSRP promotes decay of Per2 mRNA through an RNA-protein interaction and show that increased Per2 expression is responsible for the phase delay in cycling of several clock genes in the absence of KSRP. Similar to Ksrp(-/-) livers, both expression of lipogenic genes and intracellular TG levels are also reduced in Ksrp(-/-) hepatocytes due to increased Per2 expression. Using heterologous mRNA reporters, we show that the AU-rich element-containing 3' untranslated region of Per2 is responsible for KSRP-dependent mRNA decay. These findings implicate that KSRP is an important regulator of circadian expression of lipid metabolism genes in the liver likely through controlling Per2 mRNA stability.
Collapse
Affiliation(s)
- Chu-Fang Chou
- Department of Biochemistry and Molecular Genetics, University of Alabama at Birmingham, Birmingham, AL 35294
| | - Xiaolin Zhu
- Department of Nutrition Sciences, University of Alabama at Birmingham, Birmingham, AL 35294
| | - Yi-Yu Lin
- Department of Biochemistry and Molecular Genetics, University of Alabama at Birmingham, Birmingham, AL 35294
| | - Karen L Gamble
- Department of Psychiatry and Behavioral Neurobiology, University of Alabama at Birmingham, Birmingham, AL 35294
| | - W Timothy Garvey
- Department of Nutrition Sciences, University of Alabama at Birmingham, Birmingham, AL 35294
| | - Ching-Yi Chen
- Department of Biochemistry and Molecular Genetics, University of Alabama at Birmingham, Birmingham, AL 35294
| |
Collapse
|
228
|
Zhang Y, Yu L, Cai W, Fan S, Feng L, Ji G, Huang C. Protopanaxatriol, a novel PPARγ antagonist from Panax ginseng, alleviates steatosis in mice. Sci Rep 2014; 4:7375. [PMID: 25487878 PMCID: PMC4260220 DOI: 10.1038/srep07375] [Citation(s) in RCA: 54] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2014] [Accepted: 11/17/2014] [Indexed: 01/25/2023] Open
Abstract
Obesity is prevalent worldwide, and is highly associated with metabolic disorders, such as insulin resistance, hyperlipidemia and steatosis. Ginseng has been used as food and traditional herbal medicine for the treatment of various metabolic diseases. However, the molecular mechanisms how ginseng and its components participate in the regulation of lipogenesis are still largely unclear. Here, we identified that protopanaxatriol (PPT), a major ginseng constituent, inhibited rosiglitazone-supported adipocyte differentiation of 3T3-L1 cells by repressing the expression of lipogenesis-related gene expression. In high-fat diet-induced obesity (DIO) mice, PPT reduced body weight and serum lipid levels, improved insulin resistance, as well as morphology and lipid accumulation, particular macrovesicular steatosis, in the livers. These effects were confirmed with genetically obese ob/ob mice. A reporter gene assay showed that PPT specifically inhibited the transactivity of PPARγ, but not PPAR α, β/δ and LXR α, β. TR-FRET assay revealed that PPT was specifically bound to PPARγ LBD, which was further confirmed by the molecular docking study. Our data demonstrate that PPT is a novel PPARγ antagonist. The inhibition of PPARγ activity could be a promising therapy for obesity and steatosis. Our findings shed new light on the mechanism of ginseng in the treatment of metabolic syndrome.
Collapse
Affiliation(s)
- Yu Zhang
- School of Pharmacy, Shanghai University of Traditional Chinese Medicine, 1200 Cailun Road, Shanghai 201203, China
| | - Lijing Yu
- School of Pharmacy, Shanghai University of Traditional Chinese Medicine, 1200 Cailun Road, Shanghai 201203, China
| | - Wujie Cai
- School of Pharmacy, Shanghai University of Traditional Chinese Medicine, 1200 Cailun Road, Shanghai 201203, China
| | - Shengjie Fan
- School of Pharmacy, Shanghai University of Traditional Chinese Medicine, 1200 Cailun Road, Shanghai 201203, China
| | - Li Feng
- School of Pharmacy, Shanghai University of Traditional Chinese Medicine, 1200 Cailun Road, Shanghai 201203, China
| | - Guang Ji
- Institutes of Digestive Disease, Longhua Hospital, Shanghai University of Traditional Chinese Medicine, Shanghai 200032, China
| | - Cheng Huang
- School of Pharmacy, Shanghai University of Traditional Chinese Medicine, 1200 Cailun Road, Shanghai 201203, China
| |
Collapse
|
229
|
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
|
230
|
Chaix A, Zarrinpar A, Miu P, Panda S. Time-restricted feeding is a preventative and therapeutic intervention against diverse nutritional challenges. Cell Metab 2014; 20:991-1005. [PMID: 25470547 PMCID: PMC4255155 DOI: 10.1016/j.cmet.2014.11.001] [Citation(s) in RCA: 635] [Impact Index Per Article: 63.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/23/2014] [Revised: 09/15/2014] [Accepted: 10/31/2014] [Indexed: 12/21/2022]
Abstract
Because current therapeutics for obesity are limited and only offer modest improvements, novel interventions are needed. Preventing obesity with time-restricted feeding (TRF; 8-9 hr food access in the active phase) is promising, yet its therapeutic applicability against preexisting obesity, diverse dietary conditions, and less stringent eating patterns is unknown. Here we tested TRF in mice under diverse nutritional challenges. We show that TRF attenuated metabolic diseases arising from a variety of obesogenic diets, and that benefits were proportional to the fasting duration. Furthermore, protective effects were maintained even when TRF was temporarily interrupted by ad libitum access to food during weekends, a regimen particularly relevant to human lifestyle. Finally, TRF stabilized and reversed the progression of metabolic diseases in mice with preexisting obesity and type II diabetes. We establish clinically relevant parameters of TRF for preventing and treating obesity and metabolic disorders, including type II diabetes, hepatic steatosis, and hypercholesterolemia.
Collapse
Affiliation(s)
- Amandine Chaix
- Salk Institute for Biological Studies, La Jolla, CA 92037, USA
| | - Amir Zarrinpar
- Salk Institute for Biological Studies, La Jolla, CA 92037, USA; Division of Gastroenterology, University of California, San Diego, La Jolla, CA 92093, USA
| | - Phuong Miu
- Salk Institute for Biological Studies, La Jolla, CA 92037, USA
| | | |
Collapse
|
231
|
De Toro-Martín J, Fernández-Millán E, Lizárraga-Mollinedo E, López-Oliva E, Serradas P, Escrivá F, Alvarez C. Predominant role of GIP in the development of a metabolic syndrome-like phenotype in female Wistar rats submitted to forced catch-up growth. Endocrinology 2014; 155:3769-80. [PMID: 25032669 DOI: 10.1210/en.2013-2043] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
Catch-up growth has been associated with the appearance of metabolic dysfunctions such as obesity and type 2 diabetes in adulthood. Because the entero-insular axis is critical to glucose homeostasis control, we explored the relevance of the incretins glucose-dependent insulinotropic polypeptide (GIP) and glucagon-like peptide-1 (GLP-1) in the development of these pathologies. Offspring of rat dams fed ad libitum (control [C]) or 65% food-restricted during pregnancy and suckling time (undernourished [U]) were weaned onto a high-fat (HF) diet (CHF and UHF, respectively) to drive catch-up growth. Both male and female UHF rats showed an obese phenotype characterized by hyperphagy, visceral fat accumulation, and adipocyte hypertrophy. High-fat diet induced deterioration of glucose tolerance in a sex-dependent manner. Female UHF rats experienced much more severe glucose intolerance than males, which was not compensated by insulin hypersecretion, suggesting insulin resistance, as shown by homeostatic model assessment of insulin resistance values. Moreover, female, but not male, UHF rats displayed enhanced GIP but not GLP-1 secretion during oral glucose tolerance test. Administration of the GIP receptor antagonist (Pro3)GIP to UHF female rats over 21 days markedly reduced visceral fat mass and adipocyte hypertrophy without variations in food intake or body weight. These changes were accompanied by improvement of glucose tolerance and insulin sensitivity. In conclusion, the exacerbated production and secretion of GIP after the catch-up growth seems to represent the stimulus for insulin hypersecretion and insulin resistance, ultimately resulting in derangement of glucose homeostasis. Overall, these data evidence the role of GIP as a critical link between catch-up growth and the development of metabolic disturbances.
Collapse
Affiliation(s)
- J De Toro-Martín
- Departments of Biochemistry and Molecular Biology II (J.D.T.-M., E.L.-M., F.E., C.A.) and Physiology (E.L.-O.), Faculty of Pharmacy, University Complutense of Madrid, 28040 Madrid, Spain; Centro de Investigación Biomédica en Red de Diabetes y Enfermedades Metabólicas Asociadas (E.F.-M., E.L.-M., F.E., C.A.), Instituto de Salud Carlos III, 28029 Madrid, Spain; and Inserm Unité Mixte de Recherche S 1138 (P.S.), Centre de Recherche des Cordeliers, Sorbonne Universités, Université Pierre et Marie Curie-Paris 6, F-75006 Paris, France
| | | | | | | | | | | | | |
Collapse
|
232
|
Ma Y, Gao M, Liu D. Chlorogenic acid improves high fat diet-induced hepatic steatosis and insulin resistance in mice. Pharm Res 2014; 32:1200-9. [PMID: 25248334 DOI: 10.1007/s11095-014-1526-9] [Citation(s) in RCA: 135] [Impact Index Per Article: 13.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2014] [Accepted: 09/12/2014] [Indexed: 12/28/2022]
Abstract
PURPOSE Chlorogenic acid (CGA), the most abundant component in coffee, has exhibited many biological activities. The objective of this study is to assess preventive and therapeutic effects of CGA on obesity and obesity-related liver steatosis and insulin resistance. METHODS Two sets of experiments were conducted. In set 1, 6-week old C57BL/6 mice were fed a regular chow or high-fat diet (HFD) for 15 weeks with twice intra-peritoneal (IP) injection of CGA (100 mg/kg) or DMSO (carrier solution) per week. In set 2, obese mice (average 50 g) were treated by CGA (100 mg/kg, IP, twice weekly) or DMSO for 6 weeks. Body weight, body composition and food intake were monitored. Blood glucose, insulin and lipid levels were measured at end of the study. Hepatic lipid accumulation and glucose homeostasis were evaluated. Additionally, genes involved in lipid metabolism and inflammation were analyzed by real time PCR. RESULTS CGA significantly blocked the development of diet-induced obesity but did not affect body weight in obese mice. CGA treatment curbed HFD-induced hepatic steatosis and insulin resistance. Quantitative PCR analysis shows that CGA treatment suppressed hepatic expression of Pparγ, Cd36, Fabp4, and Mgat1 gene. CGA treatment also attenuated inflammation in the liver and white adipose tissue accompanied by a decrease in mRNA levels of macrophage marker genes including F4/80, Cd68, Cd11b, Cd11c, and Tnfα, Mcp-1 and Ccr2 encoding inflammatory proteins. CONCLUSION Our study provides direct evidence in support of CGA as a potent compound in preventing diet-induced obesity and obesity-related metabolic syndrome. Our results suggest that drinking coffee is beneficial in maintaining metabolic homeostasis when on a high fat diet.
Collapse
Affiliation(s)
- Yongjie Ma
- Department of Pharmaceutical and Biomedical Sciences, College of Pharmacy, University of Georgia, Room 450 Pharmacy South, 250 West Green Street, Athens, Georgia, 30602, USA
| | | | | |
Collapse
|
233
|
Ghrelin promotes hepatic lipogenesis by activation of mTOR-PPARγ signaling pathway. Proc Natl Acad Sci U S A 2014; 111:13163-8. [PMID: 25157160 DOI: 10.1073/pnas.1411571111] [Citation(s) in RCA: 91] [Impact Index Per Article: 9.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
Although ghrelin has been demonstrated to stimulate energy intake and storage through a central mechanism, its effect on hepatic lipid metabolism remains largely uncharacterized. Ghrelin receptor antagonism or gene deletion significantly decreased obesity-associated hepatic steatosis by suppression of de novo lipogenesis, whereas exogenous ghrelin stimulated lipogenesis, leading to hepatic lipid accumulation in mice. The effects of ghrelin were mediated by direct activation of its receptor on hepatocytes. Cultured hepatocytes responded to ghrelin with increased lipid content and expression of lipogenesis-related genes. Ghrelin increased phosphorylation of S6, the downstream target of mammalian target of rapamycin (mTOR) signaling in cultured hepatocytes, whereas ghrelin receptor antagonism reduced hepatic phosphorylation of S6 in db/db mice. Inhibition of mTOR signaling by rapamycin markedly attenuated ghrelin-induced up-regulation of lipogenesis in hepatocytes, whereas activation of hepatic mTOR signaling by deletion of TSC1 increased hepatic lipogenesis. By interacting with peroxisome proliferator-activated receptor-γ (PPARγ), mTOR mediates the ghrelin-induced up-regulation of lipogenesis in hepatocytes. The stimulatory effect of ghrelin on hepatic lipogenesis was significantly attenuated by PPARγ antagonism in cultured hepatocytes and in PPARγ gene-deficient mice. Our study indicates that ghrelin activates its receptor on hepatocytes to promote lipogenesis via a mechanism involving the mTOR-PPARγ signaling pathway.
Collapse
|
234
|
Krautbauer S, Eisinger K, Hader Y, Buechler C. Free fatty acids and IL-6 induce adipocyte galectin-3 which is increased in white and brown adipose tissues of obese mice. Cytokine 2014; 69:263-71. [PMID: 25043674 DOI: 10.1016/j.cyto.2014.06.016] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2013] [Revised: 12/09/2013] [Accepted: 06/23/2014] [Indexed: 11/29/2022]
Abstract
Galectin-3 regulates immune cell function and clearance of advanced glycation end products. Galectin-3 is increased in serum of obese humans and mice and most studies suggest that this protein protects from inflammation in metabolic diseases. Current data show that galectin-3 is markedly elevated in the liver, subcutaneous and intra-abdominal fat depots of mice fed a high fat diet and ob/ob mice. Galectin-3 is also increased in brown adipose tissues of these animals and immunohistochemistry confirms higher levels in adipocytes. Raised galectin-3 in obese white adipocytes has been described in the literature and regulation of adipocyte galectin-3 by metabolites with a role in obesity has been analyzed. Galectin-3 is expressed in 3T3-L1 fibroblasts and human preadipocytes and is modestly induced in mature adipocytes. In 3T3-L1 adipocytes galectin-3 is localized in the cytoplasm and is also detected in cell supernatants. Glucose does not alter soluble galectin-3. Lipopolysaccharide has no effect while TNF reduces and IL-6 raises this lectin in cell supernatants. Palmitate and oleate modestly elevate soluble galectin-3. Differentiation of 3T3-L1 cells in the presence of 100 μM and 200 μM linoleate induces soluble galectin-3 and cellular levels are upregulated by the higher concentration. Current data suggest that free fatty acids and IL-6 increase galectin-3 in adipocytes and thereby may contribute to higher levels in obesity.
Collapse
Affiliation(s)
- Sabrina Krautbauer
- Department of Internal Medicine I, Regensburg University Hospital, Regensburg, Germany
| | - Kristina Eisinger
- Department of Internal Medicine I, Regensburg University Hospital, Regensburg, Germany
| | - Yvonne Hader
- Department of Internal Medicine I, Regensburg University Hospital, Regensburg, Germany
| | - Christa Buechler
- Department of Internal Medicine I, Regensburg University Hospital, Regensburg, Germany.
| |
Collapse
|
235
|
Gurzov EN, Tran M, Fernandez-Rojo MA, Merry TL, Zhang X, Xu Y, Fukushima A, Waters MJ, Watt MJ, Andrikopoulos S, Neel BG, Tiganis T. Hepatic oxidative stress promotes insulin-STAT-5 signaling and obesity by inactivating protein tyrosine phosphatase N2. Cell Metab 2014; 20:85-102. [PMID: 24954415 PMCID: PMC4335267 DOI: 10.1016/j.cmet.2014.05.011] [Citation(s) in RCA: 76] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/12/2013] [Revised: 03/23/2014] [Accepted: 04/28/2014] [Indexed: 12/18/2022]
Abstract
Hepatic insulin resistance is a key contributor to the pathogenesis of obesity and type 2 diabetes (T2D). Paradoxically, the development of insulin resistance in the liver is not universal, but pathway selective, such that insulin fails to suppress gluconeogenesis but promotes lipogenesis, contributing to the hyperglycemia, steatosis, and hypertriglyceridemia that underpin the deteriorating glucose control and microvascular complications in T2D. The molecular basis for the pathway-specific insulin resistance remains unknown. Here we report that oxidative stress accompanying obesity inactivates protein-tyrosine phosphatases (PTPs) in the liver to activate select signaling pathways that exacerbate disease progression. In obese mice, hepatic PTPN2 (TCPTP) inactivation promoted lipogenesis and steatosis and insulin-STAT-5 signaling. The enhanced STAT-5 signaling increased hepatic IGF-1 production, which suppressed central growth hormone release and exacerbated the development of obesity and T2D. Our studies define a mechanism for the development of selective insulin resistance with wide-ranging implications for diseases characterized by oxidative stress.
Collapse
Affiliation(s)
- Esteban N Gurzov
- Department of Biochemistry and Molecular Biology, Monash University, Wellington Road, Clayton, VIC 3800, Australia
| | - Melanie Tran
- Department of Biochemistry and Molecular Biology, Monash University, Wellington Road, Clayton, VIC 3800, Australia
| | - Manuel A Fernandez-Rojo
- Department of Biochemistry and Molecular Biology, Monash University, Wellington Road, Clayton, VIC 3800, Australia
| | - Troy L Merry
- Department of Biochemistry and Molecular Biology, Monash University, Wellington Road, Clayton, VIC 3800, Australia
| | - Xinmei Zhang
- Department of Biochemistry and Molecular Biology, Monash University, Wellington Road, Clayton, VIC 3800, Australia
| | - Yang Xu
- Princess Margaret Cancer Center, University Health Network, 101 College Street, Toronto Medical Discovery Tower, University of Toronto, Toronto, ON M5G 1L7, Canada; Department of Medical Biophysics, University of Toronto, 1 King's College Circle, Toronto, ON M5S 1A8, Canada
| | - Atsushi Fukushima
- Department of Biochemistry and Molecular Biology, Monash University, Wellington Road, Clayton, VIC 3800, Australia
| | - Michael J Waters
- Institute for Molecular Bioscience, Services Road, University of Queensland, St. Lucia, QLD 4072, Australia
| | - Matthew J Watt
- Department of Physiology, Monash University, Wellington Road, Clayton, VIC 3800, Australia
| | - Sofianos Andrikopoulos
- Department of Medicine Heidelberg Repatriation Hospital, 300 Waterdale Road, Heidelberg West, The University of Melbourne, VIC 3081, Australia
| | - Benjamin G Neel
- Princess Margaret Cancer Center, University Health Network, 101 College Street, Toronto Medical Discovery Tower, University of Toronto, Toronto, ON M5G 1L7, Canada; Department of Medical Biophysics, University of Toronto, 1 King's College Circle, Toronto, ON M5S 1A8, Canada
| | - Tony Tiganis
- Department of Biochemistry and Molecular Biology, Monash University, Wellington Road, Clayton, VIC 3800, Australia.
| |
Collapse
|
236
|
Wheeler MC, Gekakis N. Hsp90 modulates PPARγ activity in a mouse model of nonalcoholic fatty liver disease. J Lipid Res 2014; 55:1702-10. [PMID: 24927728 DOI: 10.1194/jlr.m048918] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2014] [Indexed: 12/24/2022] Open
Abstract
Nonalcoholic fatty liver disease (NAFLD) is a highly prevalent complication of obesity, yet cellular mechanisms that lead to its development are not well defined. Previously, we have documented hepatic steatosis in mice carrying a mutation in the Sec61a1 gene. Here we examined the mechanism behind NAFLD in Sec61a1 mutant mice. Livers of mutant mice exhibited upregulation of Pparg and its target genes Cd36, Cidec, and Lpl, correlating with increased uptake of fatty acid. Interestingly, these mice also displayed activation of the heat shock response (HSR), with elevated levels of heat shock protein (Hsp) 70, Hsp90, and heat shock factor 1. In cell lines, inhibition of Hsp90 function reduced Pparγ signaling and protein levels. Conversely, overexpression of Hsp90 increased Pparγ signaling and protein levels by reducing degradation. This may occur via a physical interaction as Hsp90 and Pparγ coimmunoprecipitated in vivo. Furthermore, inhibition of Hsp90 in Sec61a1 mutant hepatocytes also reduced Pparγ protein levels and signaling. Finally, overexpression of Hsp90 in liver cell lines increased neutral lipid accumulation, and this accumulation was blocked by Hsp90 inhibition. Our results show that the HSR and Hsp90 play an important role in the development of NAFLD, opening new avenues for the prevention and treatment of this highly prevalent disease.
Collapse
Affiliation(s)
- Matthew C Wheeler
- Department of Cell and Molecular Biology, Scripps Research Institute, La Jolla, CA 92037
| | - Nicholas Gekakis
- Department of Cell and Molecular Biology, Scripps Research Institute, La Jolla, CA 92037
| |
Collapse
|
237
|
Matsusue K, Aibara D, Hayafuchi R, Matsuo K, Takiguchi S, Gonzalez FJ, Yamano S. Hepatic PPARγ and LXRα independently regulate lipid accumulation in the livers of genetically obese mice. FEBS Lett 2014; 588:2277-81. [PMID: 24857376 DOI: 10.1016/j.febslet.2014.05.012] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2014] [Revised: 04/22/2014] [Accepted: 05/02/2014] [Indexed: 12/23/2022]
Abstract
The nuclear hormone receptors liver X receptor α (LXRα) and peroxisome proliferator-activated receptor γ (PPARγ) play key roles in the development of fatty liver. To determine the link between hepatic PPARγ and LXRα signaling and the development of fatty liver, a LXRα-specific ligand, T0901317, was administered to normal OB/OB and genetically obese (ob/ob) mice lacking hepatic PPARγ (Pparγ(ΔH)). In ob/ob-Pparγ(ΔH) and OB/OB-Pparγ(ΔH) mice, as well as ob/ob-Pparγ(WT) and OB/OB-Pparγ(WT) mice, the liver weights and hepatic triglyceride levels were markedly increased in response to T0901317 treatment. These results suggest that hepatic PPARγ and LXRα signals independently contribute to the development of fatty liver.
Collapse
Affiliation(s)
- Kimihiko Matsusue
- Faculty of Pharmaceutical Science, Fukuoka University, 8-19-1 Nanakuma, Jonan-ku, Fukuoka 814-0180, Japan.
| | - Daisuke Aibara
- Faculty of Pharmaceutical Science, Fukuoka University, 8-19-1 Nanakuma, Jonan-ku, Fukuoka 814-0180, Japan
| | - Risa Hayafuchi
- Faculty of Pharmaceutical Science, Fukuoka University, 8-19-1 Nanakuma, Jonan-ku, Fukuoka 814-0180, Japan
| | - Kohei Matsuo
- Faculty of Pharmaceutical Science, Fukuoka University, 8-19-1 Nanakuma, Jonan-ku, Fukuoka 814-0180, Japan
| | - Soichi Takiguchi
- Institute for Clinical Research, National Kyushu Cancer Center, 3-1-1 Notame, Minami-ku, Fukuoka 811-1395, Japan
| | - Frank J Gonzalez
- Laboratory of Metabolism, National Cancer Institute, National Institutes of Health, Bethesda, MD 20892, USA
| | - Shigeru Yamano
- Faculty of Pharmaceutical Science, Fukuoka University, 8-19-1 Nanakuma, Jonan-ku, Fukuoka 814-0180, Japan
| |
Collapse
|
238
|
Kim SC, Kim C, Axe D, Cook A, Lee M, Li T, Smallwood N, Chiang JY, Hardwick JP, Moore DD, Lee YK. All-trans-retinoic acid ameliorates hepatic steatosis in mice by a novel transcriptional cascade. Hepatology 2014; 59:1750-60. [PMID: 24038081 PMCID: PMC4008145 DOI: 10.1002/hep.26699] [Citation(s) in RCA: 61] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/25/2013] [Accepted: 08/16/2013] [Indexed: 01/06/2023]
Abstract
UNLABELLED Mice deficient in small heterodimer partner (SHP) are protected from diet-induced hepatic steatosis resulting from increased fatty acid oxidation and decreased lipogenesis. The decreased lipogenesis appears to be a direct consequence of very low expression of peroxisome proliferator-activated receptor gamma 2 (PPAR-γ2), a potent lipogenic transcription factor, in the SHP(-/-) liver. The current study focused on the identification of a SHP-dependent regulatory cascade that controls PPAR-γ2 gene expression, thereby regulating hepatic fat accumulation. Illumina BeadChip array (Illumina, Inc., San Diego, CA) and real-time polymerase chain reaction were used to identify genes responsible for the linkage between SHP and PPAR-γ2 using hepatic RNAs isolated from SHP(-/-) and SHP-overexpressing mice. The initial efforts identify that hairy and enhancer of split 6 (Hes6), a novel transcriptional repressor, is an important mediator of the regulation of PPAR-γ2 transcription by SHP. The Hes6 promoter is specifically activated by the retinoic acid receptor (RAR) in response to its natural agonist ligand, all-trans retinoic acid (atRA), and is repressed by SHP. Hes6 subsequently represses hepatocyte nuclear factor 4 alpha (HNF-4α)-activated PPAR-γ2 gene expression by direct inhibition of HNF-4α transcriptional activity. Furthermore, we provide evidences that atRA treatment or adenovirus-mediated RAR-α overexpression significantly reduced hepatic fat accumulation in obese mouse models, as observed in earlier studies, and the beneficial effect is achieved by the proposed transcriptional cascade. CONCLUSIONS Our study describes a novel transcriptional regulatory cascade controlling hepatic lipid metabolism that identifies retinoic acid signaling as a new therapeutic approach to nonalcoholic fatty liver diseases.
Collapse
Affiliation(s)
- Seong Chul Kim
- Department of Integrative Medical Sciences, Northeast Ohio Medical University, Rootstown, OH 44272, USA
| | - Chunki Kim
- Department of Integrative Medical Sciences, Northeast Ohio Medical University, Rootstown, OH 44272, USA
| | - David Axe
- Department of Integrative Medical Sciences, Northeast Ohio Medical University, Rootstown, OH 44272, USA
| | - Aaron Cook
- Department of Integrative Medical Sciences, Northeast Ohio Medical University, Rootstown, OH 44272, USA
| | - Mikang Lee
- Department of Integrative Medical Sciences, Northeast Ohio Medical University, Rootstown, OH 44272, USA
| | - Tiangang Li
- Department of Integrative Medical Sciences, Northeast Ohio Medical University, Rootstown, OH 44272, USA
| | - Nicole Smallwood
- Department of Integrative Medical Sciences, Northeast Ohio Medical University, Rootstown, OH 44272, USA
| | - John Y.L. Chiang
- Department of Integrative Medical Sciences, Northeast Ohio Medical University, Rootstown, OH 44272, USA
| | - James P. Hardwick
- Department of Integrative Medical Sciences, Northeast Ohio Medical University, Rootstown, OH 44272, USA
| | - David D. Moore
- Department of Molecular and Cellular Biology, Baylor College of Medicine, Houston, TX 77038, USA
| | - Yoon Kwang Lee
- Department of Integrative Medical Sciences, Northeast Ohio Medical University, Rootstown, OH 44272, USA
| |
Collapse
|
239
|
Xu E, Forest MP, Schwab M, Avramoglu RK, St-Amand E, Caron AZ, Bellmann K, Shum M, Voisin G, Paquet M, Montoudis A, Lévy E, Siminovitch KA, Neel BG, Beauchemin N, Marette A. Hepatocyte-specific Ptpn6 deletion promotes hepatic lipid accretion, but reduces NAFLD in diet-induced obesity: potential role of PPARγ. Hepatology 2014; 59:1803-15. [PMID: 24327268 DOI: 10.1002/hep.26957] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/13/2013] [Accepted: 11/27/2013] [Indexed: 01/04/2023]
Abstract
UNLABELLED Hepatocyte-specific Shp1 knockout mice (Ptpn6(H-KO)) are protected from hepatic insulin resistance evoked by high-fat diet (HFD) feeding for 8 weeks. Unexpectedly, we report herein that Ptpn6(H-KO) mice fed an HFD for up to 16 weeks are still protected from insulin resistance, but are more prone to hepatic steatosis, as compared with their HFD-fed Ptpn6(f/f) counterparts. The livers from HFD-fed Ptpn6(H-KO) mice displayed 1) augmented lipogenesis, marked by increased expression of several hepatic genes involved in fatty acid biosynthesis, 2) elevated postprandial fatty acid uptake, and 3) significantly reduced lipid export with enhanced degradation of apolipoprotein B (ApoB). Despite more extensive hepatic steatosis, the inflammatory profile of the HFD-fed Ptpn6(H-KO) liver was similar (8 weeks) or even improved (16 weeks) as compared to their HFD-fed Ptpn6(f/f) littermates, along with reduced hepatocellular damage as revealed by serum levels of hepatic enzymes. Interestingly, comparative microarray analysis revealed a significant up-regulation of peroxisome proliferator-activated receptor gamma (PPARγ) gene expression, confirmed by quantitative polymerase chain reaction. Elevated PPARγ nuclear activity also was observed and found to be directly regulated by Shp1 in a cell-autonomous manner. CONCLUSION These findings highlight a novel role for hepatocyte Shp1 in the regulation of PPARγ and hepatic lipid metabolism. Shp1 deficiency prevents the development of severe hepatic inflammation and hepatocellular damage in steatotic livers, presenting hepatocyte Shp1 as a potential novel mediator of nonalcoholic fatty liver diseases in obesity.
Collapse
Affiliation(s)
- Elaine Xu
- Department of Medicine, Cardiology Axis of the Institut Universitaire de Cardiologie et de Pneumologie de Québec (Hôpital Laval), Ste-Foy, Québec, Canada
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | |
Collapse
|
240
|
Seoane-Collazo P, Martínez de Morentin PB, Fernø J, Diéguez C, Nogueiras R, López M. Nicotine improves obesity and hepatic steatosis and ER stress in diet-induced obese male rats. Endocrinology 2014; 155:1679-89. [PMID: 24517227 DOI: 10.1210/en.2013-1839] [Citation(s) in RCA: 76] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
Nicotine, the main addictive component of tobacco, promotes body weight reduction in humans and rodents. Recent evidence has suggested that nicotine acts in the central nervous system to modulate energy balance. Specifically, nicotine modulates hypothalamic AMP-activated protein kinase to decrease feeding and to increase brown adipose tissue thermogenesis through the sympathetic nervous system, leading to weight loss. Of note, most of this evidence has been obtained in animal models fed with normal diet or low-fat diet (LFD). However, its effectiveness in obese models remains elusive. Because obesity causes resistance towards many factors involved in energy homeostasis, the aim of this study has been to compare the effect of nicotine in a diet-induced obese (DIO) model, namely rats fed a high-fat diet, with rats fed a LFD. Our data show that chronic peripheral nicotine treatment reduced body weight by decreasing food intake and increasing brown adipose tissue thermogenesis in both LFD and DIO rats. This overall negative energy balance was associated to decreased activation of hypothalamic AMP-activated protein kinase in both models. Furthermore, nicotine improved serum lipid profile, decreased insulin serum levels, as well as reduced steatosis, inflammation, and endoplasmic reticulum stress in the liver of DIO rats but not in LFD rats. Overall, this evidence suggests that nicotine diminishes body weight and improves metabolic disorders linked to DIO and might offer a clear-cut strategy to develop new therapeutic approaches against obesity and its metabolic complications.
Collapse
Affiliation(s)
- Patricia Seoane-Collazo
- Department of Physiology (P.S.-C., P.B.M.d.M., C.D., R.N., M.L.), NeuObesity Group, Centro singular de investigación en medicina molecular y enfermedades crónicas (CIMUS), University of Santiago de Compostela-Instituto de Investigación Sanitaria, Santiago de Compostela 15782, Spain; Centro de investigación biomédica en red Fisiopatología de la Obesidad y Nutrición (P.S.-C., P.B.M.d.M., C.D., R.N., M.L.), Santiago de Compostela 15706, Spain; and Department of Clinical Science (J.F.), University of Bergen, N-5020 Bergen, Norway
| | | | | | | | | | | |
Collapse
|
241
|
Lee YJ, Yu JH, Kim WH, Kim JW. New mechanisms contributing to hepatic steatosis: glucose, insulin, and lipid signaling. Anim Cells Syst (Seoul) 2014. [DOI: 10.1080/19768354.2014.906502] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023] Open
|
242
|
Kim DH, Zhang T, Lee S, Calabuig-Navarro V, Yamauchi J, Piccirillo A, Fan Y, Uppala R, Goetzman E, Dong HH. FoxO6 integrates insulin signaling with MTP for regulating VLDL production in the liver. Endocrinology 2014; 155:1255-67. [PMID: 24437489 PMCID: PMC3959596 DOI: 10.1210/en.2013-1856] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
Abstract
Excessive production of triglyceride-rich very low-density lipoproteins (VLDL-TG) contributes to hypertriglyceridemia in obesity and type 2 diabetes. To understand the underlying mechanism, we studied hepatic regulation of VLDL-TG production by (forkhead box O6) FoxO6, a forkhead transcription factor that integrates insulin signaling to hepatic metabolism. We showed that transgenic mice expressing a constitutively active FoxO6 allele developed hypertriglyceridemia, culminating in elevated VLDL-TG levels and impaired postprandial TG clearance. This effect resulted in part from increased hepatic VLDL-TG production. We recapitulated these findings in cultured HepG2 cells and human primary hepatocytes, demonstrating that FoxO6 promoted hepatic VLDL-TG secretion. This action correlated with the ability of FoxO6 to stimulate hepatic production of microsomal triglyceride transfer protein (MTP), a molecular chaperone that catalyzes the rate-limiting step in VLDL-TG assembly and secretion. FoxO6 was shown to bind to the MTP promoter and stimulate MTP promoter activity in HepG2 cells. This effect was inhibited by insulin, consistent with the ability of insulin to promote FoxO6 phosphorylation and disable FoxO6 DNA-binding activity. Mutations of the FoxO6 target site within the MTP promoter abrogated FoxO6-mediated induction of MTP promoter activity. Hepatic FoxO6 expression became deregulated in insulin-resistant mice with obesity and type 2 diabetes. FoxO6 inhibition in insulin-resistant liver suppressed hepatic MTP expression and curbed VLDL-TG overproduction, contributing to the amelioration of hypertriglyceridemia in obese and diabetic db/db mice. These results characterize FoxO6 as an important signaling molecule upstream of MTP for regulating hepatic VLDL-TG production.
Collapse
Affiliation(s)
- Dae Hyun Kim
- Division of Immunogenetics (D.H.K., T.Z., S.L., V.C.-N., J.Y., A.P., Y.F., H.H.D.) and Division of Genetics (R.U., E.G.), Department of Pediatrics, Children's Hospital of Pittsburgh of University of Pittsburgh Medical Center, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania 15224
| | | | | | | | | | | | | | | | | | | |
Collapse
|
243
|
Affiliation(s)
- Sihao Liu
- Gene Expression Laboratory, Salk Institute for Biological Studies, 10010 North Torrey Pines Road, La Jolla, CA 92037, USA
| | - Ronald M Evans
- Howard Hughes Medical Institute, Salk Institute for Biological Studies, 10010 North Torrey Pines Road, La Jolla, CA 92037, USA
| |
Collapse
|
244
|
Peng J, Huan Y, Jiang Q, Sun SJ, Jia CM, Shen ZF. Effects and Potential Mechanisms of Pioglitazone on Lipid Metabolism in Obese Diabetic KKAy Mice. PPAR Res 2014; 2014:538183. [PMID: 24799887 PMCID: PMC3988943 DOI: 10.1155/2014/538183] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/27/2013] [Revised: 02/20/2014] [Accepted: 02/20/2014] [Indexed: 01/27/2023] Open
Abstract
This study aimed to analyze the effects and potential mechanisms of pioglitazone on triglyceride and cholesterol metabolism in obese diabetic KKAy mice. Pioglitazone was orally administered to KKAy mice over 30 days. Compared to C57BL/6J mice, KKAy mice developed obvious insulin resistance, hepatic steatosis, and hyperlipidemia. Pioglitazone treatment resulted in deteriorated microvesicular steatosis and elevated hepatic triglyceride levels, though plasma triglyceride and free fatty acid levels were reduced by the treatment, compared to nontreated KKAy mice. Plasma alanine aminotransferase activities were also significantly increased. Additionally, pioglitazone increased plasma concentrations of total cholesterol, HDL-cholesterol, and LDL-cholesterol but decreased hepatic cholesterol. Gene expression profiling revealed that pioglitazone stimulated hepatic peroxisome proliferator-activated receptor gamma hyperactivity, and induced the upregulation of adipocyte-specific and lipogenesis-related genes but downregulated of genes involved in triglyceride lipolysis and fatty acid β -oxidation. Pioglitazone also regulated the genes expression of hepatic cholesterol uptake and excretion, such as low density lipoprotein receptor (LDL-R) and scavenger receptor type-BI (SR-BI). These results suggested that pioglitazone could induce excessive hepatic triglyceride accumulation, thus aggravating liver steatosis and lesions in KKAy mice. Furthermore, pioglitazone may suppress the clearance of serum cholesterol from the liver predominantly through inhibition of LDL-R and SR-BI expression, thus increasing the plasma cholesterol.
Collapse
Affiliation(s)
- Jun Peng
- State Key Laboratory of Bioactive Substances and Functions of Natural Medicines, Institute of Materia Medica, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing 100050, China
| | - Yi Huan
- State Key Laboratory of Bioactive Substances and Functions of Natural Medicines, Institute of Materia Medica, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing 100050, China
| | - Qian Jiang
- State Key Laboratory of Bioactive Substances and Functions of Natural Medicines, Institute of Materia Medica, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing 100050, China
| | - Su-juan Sun
- State Key Laboratory of Bioactive Substances and Functions of Natural Medicines, Institute of Materia Medica, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing 100050, China
| | - Chun-ming Jia
- State Key Laboratory of Bioactive Substances and Functions of Natural Medicines, Institute of Materia Medica, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing 100050, China
| | - Zhu-fang Shen
- State Key Laboratory of Bioactive Substances and Functions of Natural Medicines, Institute of Materia Medica, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing 100050, China
| |
Collapse
|
245
|
Direct inhibitory effects of pioglitazone on hepatic fetuin-A expression. PLoS One 2014; 9:e88704. [PMID: 24551137 PMCID: PMC3923806 DOI: 10.1371/journal.pone.0088704] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2013] [Accepted: 01/16/2014] [Indexed: 02/06/2023] Open
Abstract
Fetuin-A, a circulating glycoprotein synthesized in the liver, is involved in insulin resistance and type 2 diabetes. However, regulation of fetuin-A synthesis has remained obscure. We previously reported that pioglitazone treatment significantly reduced serum fetuin-A levels in patients with type 2 diabetes. To clarify whether pioglitazone can directory inhibit hepatic fetuin-A synthesis, we investigated the effects of pioglitazone on fetuin-A expression both in vitro and in vivo. Pioglitazone treatment suppressed mRNA and protein expression of fetuin-A in Fao hepatoma cells. Interestingly, rosiglitazone but not metformin, also inhibited fetuin-A expression. In addition, GW 9662, an inhibitor of peroxisome proliferator-activated receptor (PPAR) γ, reversed pioglitazone-induced suppression of fetuin-A, suggesting that thiazolidinedione derivatives may have common characteristics with regard to fetuin-A suppression, possibly through PPARγactivation. Finally, oral administration of pioglitazone to mice for 8 weeks resulted in suppression of hepatic fetuin-A mRNA. These findings suggest that pioglitazone may partially ameliorate insulin resistance through its direct inhibitory effects on fetuin-A expression in the liver.
Collapse
|
246
|
Gu M, Kortner TM, Penn M, Hansen AK, Krogdahl Å. Effects of dietary plant meal and soya-saponin supplementation on intestinal and hepatic lipid droplet accumulation and lipoprotein and sterol metabolism in Atlantic salmon (Salmo salar L.). Br J Nutr 2014; 111:432-44. [PMID: 24507758 DOI: 10.1017/s0007114513002717] [Citation(s) in RCA: 67] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023]
Abstract
Altered lipid metabolism has been shown in fish fed plant protein sources. The present study aimed to gain further insights into how intestinal and hepatic lipid absorption and metabolism are modulated by plant meal (PM) and soya-saponin (SA) inclusion in salmon feed. Post-smolt Atlantic salmon were fed for 10 weeks one of four diets based on fishmeal or PM, with or without 10 g/kg SA. PM inclusion resulted in decreased growth performance, excessive lipid droplet accumulation in the pyloric caeca and liver, and reduced plasma cholesterol levels. Intestinal and hepatic gene expression profiling revealed an up-regulation of the expression of genes involved in lipid absorption and lipoprotein (LP) synthesis (apo, fatty acid transporters, microsomal TAG transfer protein, acyl-CoA cholesterol acyltransferase, choline kinase and choline-phosphate cytidylyltransferase A), cholesterol synthesis (3-hydroxy-3-methylglutaryl-CoA reductase) and associated transcription factors (sterol regulatory element-binding protein 2 and PPARγ). SA inclusion resulted in reduced body pools of cholesterol and bile salts. The hepatic gene expression of the rate-limiting enzyme in bile acid biosynthesis (cytochrome P450 7A1 (cyp7a1)) as well as the transcription factor liver X receptor and the bile acid transporter abcb11 (ATP-binding cassette B11) was down-regulated by SA inclusion. A significant interaction was observed between PM inclusion and SA inclusion for plasma cholesterol levels. In conclusion, gene expression profiling suggested that the capacity for LP assembly and cholesterol synthesis was up-regulated by PM exposure, probably as a compensatory mechanism for excessive lipid droplet accumulation and reduced plasma cholesterol levels. SA inclusion had hypocholesterolaemic effects on Atlantic salmon, accompanied by decreased bile salt metabolism.
Collapse
Affiliation(s)
- Min Gu
- Department of Basic Science and Aquatic Medicine, Norwegian School of Veterinary Science, Aquaculture Protein Centre (a CoE), PO Box 8146 Dep, NO-0033 Oslo, Norway
| | - Trond M Kortner
- Department of Basic Science and Aquatic Medicine, Norwegian School of Veterinary Science, Aquaculture Protein Centre (a CoE), PO Box 8146 Dep, NO-0033 Oslo, Norway
| | - Michael Penn
- Department of Basic Science and Aquatic Medicine, Norwegian School of Veterinary Science, Aquaculture Protein Centre (a CoE), PO Box 8146 Dep, NO-0033 Oslo, Norway
| | | | - Åshild Krogdahl
- Department of Basic Science and Aquatic Medicine, Norwegian School of Veterinary Science, Aquaculture Protein Centre (a CoE), PO Box 8146 Dep, NO-0033 Oslo, Norway
| |
Collapse
|
247
|
Birkenfeld AL, Shulman GI. Nonalcoholic fatty liver disease, hepatic insulin resistance, and type 2 diabetes. Hepatology 2014; 59:713-23. [PMID: 23929732 PMCID: PMC3946772 DOI: 10.1002/hep.26672] [Citation(s) in RCA: 512] [Impact Index Per Article: 51.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/10/2013] [Accepted: 07/31/2013] [Indexed: 12/12/2022]
Abstract
Nonalcoholic fatty liver disease (NAFLD), hepatic insulin resistance, and type 2 diabetes are all strongly associated and are all reaching epidemic proportions. Whether there is a causal link between NAFLD and hepatic insulin resistance is controversial. This review will discuss recent studies in both humans and animal models of NAFLD that have implicated increases in hepatic diacylglycerol (DAG) content leading to activation of novel protein kinase Cϵ (PKCϵ) resulting in decreased insulin signaling in the pathogenesis of NAFLD-associated hepatic insulin resistance and type 2 diabetes. The DAG-PKCϵ hypothesis can explain the occurrence of hepatic insulin resistance observed in most cases of NAFLD associated with obesity, lipodystrophy, and type 2 diabetes.
Collapse
Affiliation(s)
- Andreas L. Birkenfeld
- Charité - University School of Medicine, Department of Endocrinology Diabetes and Nutrition, Center for Cardiovascular Research, Berlin, Germany
- Howard Hughes Medical Institute and the Departments of Internal Medicine and Cellular & Molecular Physiology, Yale University School of Medicine, New Haven, CT, USA
| | - Gerald I. Shulman
- Howard Hughes Medical Institute and the Departments of Internal Medicine and Cellular & Molecular Physiology, Yale University School of Medicine, New Haven, CT, USA
| |
Collapse
|
248
|
Wu CH, Ou TT, Chang CH, Chang XZ, Yang MY, Wang CJ. The polyphenol extract from Sechium edule shoots inhibits lipogenesis and stimulates lipolysis via activation of AMPK signals in HepG2 cells. JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY 2014; 62:750-9. [PMID: 24377368 DOI: 10.1021/jf404611a] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/18/2023]
Abstract
Fatty liver may have implications for metabolic syndrome, such as obesity, hypertension, and diabetes. Therefore, the development of pharmacological or natural agents to reduce fat accumulation in the liver is an important effort. The Sechium edule shoots have already been verified to decrease serum lipids and cholesterol and prevent atherosclerosis. However, how Sechium edule shoots modulate hepatic lipid metabolism is unclear. This study was designed to investigate the effects and mechanisms of polyphenol extracts (SPE) of Sechium edule shoots in reducing lipid accumulation in oleic acid-treated HepG2 cells. We found that water extracts (SWE) of Sechium edule shoots could decrease serum and hepatic lipid contents (e.g., triacylglycerol and cholesterol). Furthermore, SWE and SPE through the AMPK (AMP-activating protein kinase) signaling pathway could decrease lipogenic relative enzymes, such as FAS (fatty acid synthase), HMGCoR (HMG-CoA reductase), and SREBPs (sterol regulatory element binding proteins), and increase the expression of CPT-I (carnitine palmitoyltransferase I) and PPARα (peroxisome proliferators activated receptor α), which are critical regulators of hepatic lipid metabolism. These observations suggested that Sechium edule shoots have potential for developing health foods for preventing and remedying fatty liver.
Collapse
Affiliation(s)
- Cheng-Hsun Wu
- Department of Anatomy, China Medical University , Taichung 40402, Taiwan
| | | | | | | | | | | |
Collapse
|
249
|
Saremi B, Winand S, Friedrichs P, Kinoshita A, Rehage J, Dänicke S, Häussler S, Breves G, Mielenz M, Sauerwein H. Longitudinal profiling of the tissue-specific expression of genes related with insulin sensitivity in dairy cows during lactation focusing on different fat depots. PLoS One 2014; 9:e86211. [PMID: 24465964 PMCID: PMC3897665 DOI: 10.1371/journal.pone.0086211] [Citation(s) in RCA: 48] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2013] [Accepted: 12/09/2013] [Indexed: 01/13/2023] Open
Abstract
In dairy cows the milk associated energy output in early lactation exceeds the input via voluntary feed intake. To spare glucose for mammary lactose synthesis, peripheral insulin sensitivity (IS) is reduced and fat mobilization is stimulated. For these processes a link between IS and the endocrine functions of adipose tissue (AT) is likely; we thus aimed to characterise the mRNA expression from bovine AT derived proteins and receptors that are related to IS according to the literature in metabolically active tissues plus systemic IS throughout lactation. Conjugated linoleic acids (CLA) reduce milk fat thus decreasing the milk drain of energy and potentially dampening lipolysis, but may also affect IS. Subcutaneous (s.c.) AT and liver from pluriparous cows receiving either control fat or CLA supplement (100 g/day from 1 to 182 days in milk each) were biopsied covering week -3 to 36 relative to parturition. In an additional trial with primiparous cows treated analogously and slaughtered on days in milk 1, 42 or 105, samples from liver, udder, skeletal muscle and 3 visceral and 3 s.c. AT were obtained and assayed for mRNA abundance of adiponectin, its receptors, leptin, leptin receptor, PPARγ, PPARγ2, IL-6, and TNF-α. In pluriparous animals, the mRNA abundance of most of the target genes decreased after parturition in s.c. AT but increased in liver. In primiparous cows, AT depot specific differences were mostly related to retroperitoneal AT; adiponectin receptor 1 and TNF-α were affected predominantly. CLA effects in primiparous cows were largely limited to decreased PPARγ2 mRNA abundance in udder tissue. In pluriparous cows, insulin secretion was increased by CLA resulting in decreased systemic IS but without consistent changes in tissue target mRNA abundance. The temporal gene expression profiles from the adipokines and related receptors support their coactive function in adapting to the needs of lactation.
Collapse
Affiliation(s)
- Behnam Saremi
- Institute of Animal Science, Physiology and Hygiene Unit, University of Bonn, Bonn, Germany
| | - Sarah Winand
- Institute of Animal Science, Physiology and Hygiene Unit, University of Bonn, Bonn, Germany
| | - Paula Friedrichs
- Institute of Animal Science, Physiology and Hygiene Unit, University of Bonn, Bonn, Germany
| | - Asako Kinoshita
- Clinic for Cattle, University of Veterinary Medicine Hannover, Foundation, Hannover, Germany
| | - Jürgen Rehage
- Clinic for Cattle, University of Veterinary Medicine Hannover, Foundation, Hannover, Germany
| | - Sven Dänicke
- Institute of Animal Nutrition, Friedrich-Loeffler-Institute (FLI), Federal Research Institute for Animal Health, Braunschweig, Germany
| | - Susanne Häussler
- Institute of Animal Science, Physiology and Hygiene Unit, University of Bonn, Bonn, Germany
| | - Gerhard Breves
- Department of Physiology, University of Veterinary Medicine Hannover, Foundation, Hannover, Germany
| | - Manfred Mielenz
- Institute of Animal Science, Physiology and Hygiene Unit, University of Bonn, Bonn, Germany
| | - Helga Sauerwein
- Institute of Animal Science, Physiology and Hygiene Unit, University of Bonn, Bonn, Germany
| |
Collapse
|
250
|
Hasenfuss SC, Bakiri L, Thomsen MK, Williams EG, Auwerx J, Wagner EF. Regulation of steatohepatitis and PPARγ signaling by distinct AP-1 dimers. Cell Metab 2014; 19:84-95. [PMID: 24411941 PMCID: PMC4023468 DOI: 10.1016/j.cmet.2013.11.018] [Citation(s) in RCA: 84] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/09/2013] [Revised: 10/20/2013] [Accepted: 11/15/2013] [Indexed: 12/17/2022]
Abstract
Nonalcoholic fatty liver disease (NAFLD) affects up to 30% of the adult population in Western societies, yet the underlying molecular pathways remain poorly understood. Here, we identify the dimeric Activator Protein 1 as a regulator of NAFLD. Fos-related antigen 1 (Fra-1) and Fos-related antigen 2 (Fra-2) prevent dietary NAFLD by inhibiting prosteatotic PPARγ signaling. Moreover, established NAFLD and the associated liver damage can be efficiently reversed by hepatocyte-specific Fra-1 expression. In contrast, c-Fos promotes PPARγ expression, while c-Jun exerts opposing, dimer-dependent functions. Interestingly, JunD was found to be essential for PPARγ signaling and NAFLD development. This unique antagonistic regulation of PPARγ by distinct AP-1 dimers occurs at the transcriptional level and establishes AP-1 as a link between obesity, hepatic lipid metabolism, and NAFLD.
Collapse
Affiliation(s)
- Sebastian C Hasenfuss
- Genes, Development, and Disease Group, F-BBVA Cancer Cell Biology Programme, National Cancer Research Centre (CNIO), 28029 Madrid, Spain; Faculty Biology, University of Freiburg, 79104 Freiburg, Germany
| | - Latifa Bakiri
- Genes, Development, and Disease Group, F-BBVA Cancer Cell Biology Programme, National Cancer Research Centre (CNIO), 28029 Madrid, Spain
| | - Martin K Thomsen
- Genes, Development, and Disease Group, F-BBVA Cancer Cell Biology Programme, National Cancer Research Centre (CNIO), 28029 Madrid, Spain
| | - Evan G Williams
- Laboratory of Integrative and Systems Physiology, School of Life Sciences, École Polytechnique Fédérale, 1015 Lausanne, Switzerland
| | - Johan Auwerx
- Laboratory of Integrative and Systems Physiology, School of Life Sciences, École Polytechnique Fédérale, 1015 Lausanne, Switzerland
| | - Erwin F Wagner
- Genes, Development, and Disease Group, F-BBVA Cancer Cell Biology Programme, National Cancer Research Centre (CNIO), 28029 Madrid, Spain.
| |
Collapse
|