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Chen L, Lu J, Hu J, Gong X. Unveiling the multifaceted role of adropin in various diseases (Review). Int J Mol Med 2024; 54:90. [PMID: 39155866 PMCID: PMC11335353 DOI: 10.3892/ijmm.2024.5414] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2024] [Accepted: 07/31/2024] [Indexed: 08/20/2024] Open
Abstract
Adropin is a secreted peptide encoded by the energy homeostasis‑associated gene, which also functions as a membrane‑bound protein facilitating intercellular communication. This peptide has been detected in various tissues and body fluids, including the brain, liver, kidney, heart, pancreas, small intestine, endothelial cells and colostrum. Notably, the amino acid sequences of adropin are identical in humans, mice and rats. Previous studies have demonstrated that adropin levels fluctuate under different physiological and pathological conditions. Adropin plays a role in regulating carbohydrate metabolism, lipid metabolism and intercellular molecular signaling pathways, implicating its involvement in the progression of numerous diseases, such as acute myocardial infarction, lung injury, non‑alcoholic fatty liver disease/non‑alcoholic steatohepatitis, kidney disease, polycystic ovary syndrome, obesity, and diabetes, atherosclerosis, systemic sclerosis and cancer. Despite its significance, the precise role and mechanism of this protein remain inadequately understood and studied. To elucidate the function of adropin and its clinical research status, a systematic review of recent studies on adropin across various diseases was conducted. Additionally, several challenges and limitations associated with adropin research in both animal and clinical contexts were identified, aiming to offer valuable insights for future investigation.
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Affiliation(s)
- Ling Chen
- Department of Nephrology, Seventh People's Hospital of Shanghai University of Traditional Chinese Medicine, Shanghai 200137, P.R. China
| | - Jianrao Lu
- Department of Nephrology, Seventh People's Hospital of Shanghai University of Traditional Chinese Medicine, Shanghai 200137, P.R. China
| | - Jing Hu
- Department of Nephrology, Seventh People's Hospital of Shanghai University of Traditional Chinese Medicine, Shanghai 200137, P.R. China
| | - Xuezhong Gong
- Department of Nephrology, Shanghai Municipal Hospital of Traditional Chinese Medicine, Shanghai University of Traditional Chinese Medicine, Shanghai 200071, P.R. China
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2
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Portincasa P, Khalil M, Mahdi L, Perniola V, Idone V, Graziani A, Baffy G, Di Ciaula A. Metabolic Dysfunction-Associated Steatotic Liver Disease: From Pathogenesis to Current Therapeutic Options. Int J Mol Sci 2024; 25:5640. [PMID: 38891828 PMCID: PMC11172019 DOI: 10.3390/ijms25115640] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2024] [Revised: 05/17/2024] [Accepted: 05/20/2024] [Indexed: 06/21/2024] Open
Abstract
The epidemiological burden of liver steatosis associated with metabolic diseases is continuously growing worldwide and in all age classes. This condition generates possible progression of liver damage (i.e., inflammation, fibrosis, cirrhosis, hepatocellular carcinoma) but also independently increases the risk of cardio-metabolic diseases and cancer. In recent years, the terminological evolution from "nonalcoholic fatty liver disease" (NAFLD) to "metabolic dysfunction-associated fatty liver disease" (MAFLD) and, finally, "metabolic dysfunction-associated steatotic liver disease" (MASLD) has been paralleled by increased knowledge of mechanisms linking local (i.e., hepatic) and systemic pathogenic pathways. As a consequence, the need for an appropriate classification of individual phenotypes has been oriented to the investigation of innovative therapeutic tools. Besides the well-known role for lifestyle change, a number of pharmacological approaches have been explored, ranging from antidiabetic drugs to agonists acting on the gut-liver axis and at a systemic level (mainly farnesoid X receptor (FXR) agonists, PPAR agonists, thyroid hormone receptor agonists), anti-fibrotic and anti-inflammatory agents. The intrinsically complex pathophysiological history of MASLD makes the selection of a single effective treatment a major challenge, so far. In this evolving scenario, the cooperation between different stakeholders (including subjects at risk, health professionals, and pharmaceutical industries) could significantly improve the management of disease and the implementation of primary and secondary prevention measures. The high healthcare burden associated with MASLD makes the search for new, effective, and safe drugs a major pressing need, together with an accurate characterization of individual phenotypes. Recent and promising advances indicate that we may soon enter the era of precise and personalized therapy for MASLD/MASH.
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Affiliation(s)
- Piero Portincasa
- Clinica Medica “A. Murri”, Department of Precision and Regenerative Medicine and Ionian Area (DiMePre-J), University of Bari “Aldo Moro”, 70124 Bari, Italy; (M.K.); (L.M.); (V.P.); (V.I.); (A.D.C.)
| | - Mohamad Khalil
- Clinica Medica “A. Murri”, Department of Precision and Regenerative Medicine and Ionian Area (DiMePre-J), University of Bari “Aldo Moro”, 70124 Bari, Italy; (M.K.); (L.M.); (V.P.); (V.I.); (A.D.C.)
| | - Laura Mahdi
- Clinica Medica “A. Murri”, Department of Precision and Regenerative Medicine and Ionian Area (DiMePre-J), University of Bari “Aldo Moro”, 70124 Bari, Italy; (M.K.); (L.M.); (V.P.); (V.I.); (A.D.C.)
| | - Valeria Perniola
- Clinica Medica “A. Murri”, Department of Precision and Regenerative Medicine and Ionian Area (DiMePre-J), University of Bari “Aldo Moro”, 70124 Bari, Italy; (M.K.); (L.M.); (V.P.); (V.I.); (A.D.C.)
| | - Valeria Idone
- Clinica Medica “A. Murri”, Department of Precision and Regenerative Medicine and Ionian Area (DiMePre-J), University of Bari “Aldo Moro”, 70124 Bari, Italy; (M.K.); (L.M.); (V.P.); (V.I.); (A.D.C.)
- Aboca S.p.a. Società Agricola, 52037 Sansepolcro, Italy
| | - Annarita Graziani
- Institut AllergoSan Pharmazeutische Produkte Forschungs- und Vertriebs GmbH, 8055 Graz, Austria;
| | - Gyorgy Baffy
- Division of Gastroenterology, Hepatology and Endoscopy, Department of Medicine, Brigham and Women’s Hospital, Harvard Medical School, Boston, MA 02115, USA;
- Section of Gastroenterology, Department of Medicine, VA Boston Healthcare System, Boston, MA 02132, USA
| | - Agostino Di Ciaula
- Clinica Medica “A. Murri”, Department of Precision and Regenerative Medicine and Ionian Area (DiMePre-J), University of Bari “Aldo Moro”, 70124 Bari, Italy; (M.K.); (L.M.); (V.P.); (V.I.); (A.D.C.)
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3
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Mao Z, Mu J, Gao Z, Huang S, Chen L. Biological Functions and Potential Therapeutic Significance of O-GlcNAcylation in Hepatic Cellular Stress and Liver Diseases. Cells 2024; 13:805. [PMID: 38786029 PMCID: PMC11119800 DOI: 10.3390/cells13100805] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2024] [Revised: 05/07/2024] [Accepted: 05/07/2024] [Indexed: 05/25/2024] Open
Abstract
O-linked-β-D-N-acetylglucosamine (O-GlcNAc) glycosylation (O-GlcNAcylation), which is dynamically regulated by O-GlcNAc transferase (OGT) and O-GlcNAcase (OGA), is a post-translational modification involved in multiple cellular processes. O-GlcNAcylation of proteins can regulate their biological functions via crosstalk with other post-translational modifications, such as phosphorylation, ubiquitination, acetylation, and methylation. Liver diseases are a major cause of death worldwide; yet, key pathological features of the disease, such as inflammation, fibrosis, steatosis, and tumorigenesis, are not fully understood. The dysregulation of O-GlcNAcylation has been shown to be involved in some severe hepatic cellular stress, viral hepatitis, liver fibrosis, nonalcoholic fatty acid liver disease (NAFLD), malignant progression, and drug resistance of hepatocellular carcinoma (HCC) through multiple molecular signaling pathways. Here, we summarize the emerging link between O-GlcNAcylation and hepatic pathological processes and provide information about the development of therapeutic strategies for liver diseases.
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Affiliation(s)
- Zun Mao
- Jiangsu Key Laboratory for Molecular and Medical Biotechnology, College of Life Sciences, Nanjing Normal University, Nanjing 210023, China; (Z.M.); (Z.G.)
| | - Junpeng Mu
- Department of Clinical Medicine, Xuzhou Medical University, Xuzhou 221004, China;
| | - Zhixiang Gao
- Jiangsu Key Laboratory for Molecular and Medical Biotechnology, College of Life Sciences, Nanjing Normal University, Nanjing 210023, China; (Z.M.); (Z.G.)
| | - Shile Huang
- Department of Biochemistry and Molecular Biology, Louisiana State University Health Sciences Center, 1501 Kings Highway, Shreveport, LA 71130-3932, USA
- Department of Hematology and Oncology, Louisiana State University Health Sciences Center, 1501 Kings Highway, Shreveport, LA 71130-3932, USA
- Feist-Weiller Cancer Center, Louisiana State University Health Sciences Center, Shreveport, LA 71130-3932, USA
| | - Long Chen
- Jiangsu Key Laboratory for Molecular and Medical Biotechnology, College of Life Sciences, Nanjing Normal University, Nanjing 210023, China; (Z.M.); (Z.G.)
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4
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Szablewski L. Changes in Cells Associated with Insulin Resistance. Int J Mol Sci 2024; 25:2397. [PMID: 38397072 PMCID: PMC10889819 DOI: 10.3390/ijms25042397] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2024] [Revised: 02/10/2024] [Accepted: 02/14/2024] [Indexed: 02/25/2024] Open
Abstract
Insulin is a polypeptide hormone synthesized and secreted by pancreatic β-cells. It plays an important role as a metabolic hormone. Insulin influences the metabolism of glucose, regulating plasma glucose levels and stimulating glucose storage in organs such as the liver, muscles and adipose tissue. It is involved in fat metabolism, increasing the storage of triglycerides and decreasing lipolysis. Ketone body metabolism also depends on insulin action, as insulin reduces ketone body concentrations and influences protein metabolism. It increases nitrogen retention, facilitates the transport of amino acids into cells and increases the synthesis of proteins. Insulin also inhibits protein breakdown and is involved in cellular growth and proliferation. On the other hand, defects in the intracellular signaling pathways of insulin may cause several disturbances in human metabolism, resulting in several chronic diseases. Insulin resistance, also known as impaired insulin sensitivity, is due to the decreased reaction of insulin signaling for glucose levels, seen when glucose use in response to an adequate concentration of insulin is impaired. Insulin resistance may cause, for example, increased plasma insulin levels. That state, called hyperinsulinemia, impairs metabolic processes and is observed in patients with type 2 diabetes mellitus and obesity. Hyperinsulinemia may increase the risk of initiation, progression and metastasis of several cancers and may cause poor cancer outcomes. Insulin resistance is a health problem worldwide; therefore, mechanisms of insulin resistance, causes and types of insulin resistance and strategies against insulin resistance are described in this review. Attention is also paid to factors that are associated with the development of insulin resistance, the main and characteristic symptoms of particular syndromes, plus other aspects of severe insulin resistance. This review mainly focuses on the description and analysis of changes in cells due to insulin resistance.
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Affiliation(s)
- Leszek Szablewski
- Chair and Department of General Biology and Parasitology, Medical University of Warsaw, Chałubińskiego Str. 5, 02-004 Warsaw, Poland
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5
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Hu YJ, Zhang X, Lv HM, Liu Y, Li SZ. Protein O-GlcNAcylation: The sweet hub in liver metabolic flexibility from a (patho)physiological perspective. Liver Int 2024; 44:293-315. [PMID: 38110988 DOI: 10.1111/liv.15812] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/07/2023] [Revised: 11/18/2023] [Accepted: 11/22/2023] [Indexed: 12/20/2023]
Abstract
O-GlcNAcylation is a dynamic, reversible and atypical O-glycosylation that regulates various cellular physiological processes via conformation, stabilisation, localisation, chaperone interaction or activity of target proteins. The O-GlcNAcylation cycle is precisely controlled by collaboration between O-GlcNAc transferase and O-GlcNAcase. Uridine-diphosphate-N-acetylglucosamine, the sole donor of O-GlcNAcylation produced by the hexosamine biosynthesis pathway, is controlled by the input of glucose, glutamine, acetyl coenzyme A and uridine triphosphate, making it a sensor of the fluctuation of molecules, making O-GlcNAcylation a pivotal nutrient sensor for the metabolism of carbohydrates, amino acids, lipids and nucleotides. O-GlcNAcylation, particularly prevalent in liver, is the core hub for controlling systemic glucose homeostasis due to its nutritional sensitivity and precise spatiotemporal regulation of insulin signal transduction. The pathology of various liver diseases has highlighted hepatic metabolic disorder and dysfunction, and abnormal O-GlcNAcylation also plays a specific pathological role in these processes. Therefore, this review describes the unique features of O-GlcNAcylation and its dynamic homeostasis maintenance. Additionally, it explains the underlying nutritional sensitivity of O-GlcNAcylation and discusses its mechanism of spatiotemporal modulation of insulin signal transduction and liver metabolic homeostasis during the fasting and feeding cycle. This review emphasises the pathophysiological implications of O-GlcNAcylation in nonalcoholic fatty liver disease, nonalcoholic steatohepatitis and hepatic fibrosis, and focuses on the adverse effects of hyper O-GlcNAcylation on liver cancer progression and metabolic reprogramming.
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Affiliation(s)
- Ya-Jie Hu
- Key Laboratory of Bovine Disease Control in Northeast China of Ministry of Agriculture and Rural affairs of the People's Republic of China, College of Animal Science and Veterinary Medicine, Heilongjiang Bayi Agricultural University, Daqing, China
| | - Xu Zhang
- Key Laboratory of Bovine Disease Control in Northeast China of Ministry of Agriculture and Rural affairs of the People's Republic of China, College of Animal Science and Veterinary Medicine, Heilongjiang Bayi Agricultural University, Daqing, China
| | - Hong-Ming Lv
- Key Laboratory of Bovine Disease Control in Northeast China of Ministry of Agriculture and Rural affairs of the People's Republic of China, College of Animal Science and Veterinary Medicine, Heilongjiang Bayi Agricultural University, Daqing, China
| | - Yang Liu
- Key Laboratory of Bovine Disease Control in Northeast China of Ministry of Agriculture and Rural affairs of the People's Republic of China, College of Animal Science and Veterinary Medicine, Heilongjiang Bayi Agricultural University, Daqing, China
| | - Shi-Ze Li
- Key Laboratory of Bovine Disease Control in Northeast China of Ministry of Agriculture and Rural affairs of the People's Republic of China, College of Animal Science and Veterinary Medicine, Heilongjiang Bayi Agricultural University, Daqing, China
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Sangro P, de la Torre Aláez M, Sangro B, D'Avola D. Metabolic dysfunction-associated fatty liver disease (MAFLD): an update of the recent advances in pharmacological treatment. J Physiol Biochem 2023; 79:869-879. [PMID: 36976456 PMCID: PMC10635944 DOI: 10.1007/s13105-023-00954-4] [Citation(s) in RCA: 15] [Impact Index Per Article: 15.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2022] [Accepted: 02/28/2023] [Indexed: 03/29/2023]
Abstract
Metabolic dysfunction-associated fatty liver disease (MAFLD) is nowadays considered the liver manifestation of metabolic syndrome. Its prevalence is increasing worldwide in parallel to the epidemic of diabetes and obesity. MAFLD includes a wide spectrum of liver injury including simple steatosis and non-alcoholic steatohepatitis (NASH) that may lead to serious complications such as liver cirrhosis and liver cancer. The complexity of its pathophysiology and the intricate mechanisms underlying disease progression explains the huge variety of molecules targeting diverse biological mechanisms that have been tested in preclinical and clinical settings in the last two decades. Thanks to the large number of clinical trials of the last few years, most of them still ongoing, the pharmacotherapy scenario of MAFLD is rapidly evolving. The three major components of MAFLD, steatosis, inflammation, and fibrosis seem to be safely targeted with different agents at least in a large proportion of patients. Likely, in the next few years more than one drug will be approved for the treatment of MAFLD at different disease stages. The aim of this review is to synthesize the characteristics and the results of the most advanced clinical trials for the treatment of NASH to evaluate the recent advances of pharmacotherapy in this disease.
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Affiliation(s)
- Paloma Sangro
- Liver Unit Clínica, Universidad de Navarra, Madrid, Spain.
| | | | - Bruno Sangro
- Liver Unit Clínica, Universidad de Navarra, Madrid, Spain
- Centro de Investigación Biomédica en Red de Enfermedades Hepáticas y Digestivas, Pamplona, Spain
| | - Delia D'Avola
- Liver Unit Clínica, Universidad de Navarra, Madrid, Spain
- Centro de Investigación Biomédica en Red de Enfermedades Hepáticas y Digestivas, Pamplona, Spain
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7
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Uehara K, Santoleri D, Whitlock AEG, Titchenell PM. Insulin Regulation of Hepatic Lipid Homeostasis. Compr Physiol 2023; 13:4785-4809. [PMID: 37358513 PMCID: PMC10760932 DOI: 10.1002/cphy.c220015] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/27/2023]
Abstract
The incidence of obesity, insulin resistance, and type II diabetes (T2DM) continues to rise worldwide. The liver is a central insulin-responsive metabolic organ that governs whole-body metabolic homeostasis. Therefore, defining the mechanisms underlying insulin action in the liver is essential to our understanding of the pathogenesis of insulin resistance. During periods of fasting, the liver catabolizes fatty acids and stored glycogen to meet the metabolic demands of the body. In postprandial conditions, insulin signals to the liver to store excess nutrients into triglycerides, cholesterol, and glycogen. In insulin-resistant states, such as T2DM, hepatic insulin signaling continues to promote lipid synthesis but fails to suppress glucose production, leading to hypertriglyceridemia and hyperglycemia. Insulin resistance is associated with the development of metabolic disorders such as cardiovascular and kidney disease, atherosclerosis, stroke, and cancer. Of note, nonalcoholic fatty liver disease (NAFLD), a spectrum of diseases encompassing fatty liver, inflammation, fibrosis, and cirrhosis, is linked to abnormalities in insulin-mediated lipid metabolism. Therefore, understanding the role of insulin signaling under normal and pathologic states may provide insights into preventative and therapeutic opportunities for the treatment of metabolic diseases. Here, we provide a review of the field of hepatic insulin signaling and lipid regulation, including providing historical context, detailed molecular mechanisms, and address gaps in our understanding of hepatic lipid regulation and the derangements under insulin-resistant conditions. © 2023 American Physiological Society. Compr Physiol 13:4785-4809, 2023.
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Affiliation(s)
- Kahealani Uehara
- Institute of Diabetes, Obesity, and Metabolism, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, USA
- Biochemistry and Molecular Biophysics Graduate Group, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, USA
| | - Dominic Santoleri
- Institute of Diabetes, Obesity, and Metabolism, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, USA
- Biochemistry and Molecular Biophysics Graduate Group, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, USA
| | - Anna E. Garcia Whitlock
- Institute of Diabetes, Obesity, and Metabolism, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, USA
- Department of Surgery, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, USA
| | - Paul M. Titchenell
- Institute of Diabetes, Obesity, and Metabolism, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, USA
- Department of Physiology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, USA
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8
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Emerging Role of Protein O-GlcNAcylation in Liver Metabolism: Implications for Diabetes and NAFLD. Int J Mol Sci 2023; 24:ijms24032142. [PMID: 36768465 PMCID: PMC9916810 DOI: 10.3390/ijms24032142] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2022] [Revised: 01/16/2023] [Accepted: 01/18/2023] [Indexed: 01/24/2023] Open
Abstract
O-linked b-N-acetyl-glucosaminylation (O-GlcNAcylation) is one of the most common post-translational modifications of proteins, and is established by modifying the serine or threonine residues of nuclear, cytoplasmic, and mitochondrial proteins. O-GlcNAc signaling is considered a critical nutrient sensor, and affects numerous proteins involved in cellular metabolic processes. O-GlcNAcylation modulates protein functions in different patterns, including protein stabilization, enzymatic activity, transcriptional activity, and protein interactions. Disrupted O-GlcNAcylation is associated with an abnormal metabolic state, and may result in metabolic disorders. As the liver is the center of nutrient metabolism, this review provides a brief description of the features of the O-GlcNAc signaling pathway, and summarizes the regulatory functions and underlying molecular mechanisms of O-GlcNAcylation in liver metabolism. Finally, this review highlights the role of O-GlcNAcylation in liver-associated diseases, such as diabetes and nonalcoholic fatty liver disease (NAFLD). We hope this review not only benefits the understanding of O-GlcNAc biology, but also provides new insights for treatments against liver-associated metabolic disorders.
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Wu J, Liu J, Lapenta K, Desrouleaux R, Li MD, Yang X. Regulation of the urea cycle by CPS1 O-GlcNAcylation in response to dietary restriction and aging. J Mol Cell Biol 2022; 14:mjac016. [PMID: 35285892 PMCID: PMC9254885 DOI: 10.1093/jmcb/mjac016] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2021] [Revised: 02/20/2022] [Accepted: 03/10/2022] [Indexed: 12/02/2022] Open
Abstract
O-linked N-acetyl-glucosamine glycosylation (O-GlcNAcylation) of intracellular proteins is a dynamic process broadly implicated in age-related disease, yet it remains uncharacterized whether and how O-GlcNAcylation contributes to the natural aging process. O-GlcNAc transferase (OGT) and the opposing enzyme O-GlcNAcase (OGA) control this nutrient-sensing protein modification in cells. Here, we show that global O-GlcNAc levels are increased in multiple tissues of aged mice. In aged liver, carbamoyl phosphate synthetase 1 (CPS1) is among the most heavily O-GlcNAcylated proteins. CPS1 O-GlcNAcylation is reversed by calorie restriction and is sensitive to genetic and pharmacological manipulations of the O-GlcNAc pathway. High glucose stimulates CPS1 O-GlcNAcylation and inhibits CPS1 activity. Liver-specific deletion of OGT potentiates CPS1 activity and renders CPS1 irresponsive to further stimulation by a prolonged fasting. Our results identify CPS1 O-GlcNAcylation as a key nutrient-sensing regulatory step in the urea cycle during aging and dietary restriction, implying a role for mitochondrial O-GlcNAcylation in nutritional regulation of longevity.
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Affiliation(s)
- Jing Wu
- Department of Comparative Medicine, Department of Cellular and Molecular Physiology, and Yale Center for Molecular and Systems Metabolism, Yale University School of Medicine, New Haven, CT 06520, USA
- School of Life Science and Technology, Xi'an Jiaotong University, Xi'an 710049, China
| | - Jiayu Liu
- Department of Comparative Medicine, Department of Cellular and Molecular Physiology, and Yale Center for Molecular and Systems Metabolism, Yale University School of Medicine, New Haven, CT 06520, USA
| | - Kalina Lapenta
- Department of Comparative Medicine, Department of Cellular and Molecular Physiology, and Yale Center for Molecular and Systems Metabolism, Yale University School of Medicine, New Haven, CT 06520, USA
| | - Reina Desrouleaux
- Department of Comparative Medicine, Department of Cellular and Molecular Physiology, and Yale Center for Molecular and Systems Metabolism, Yale University School of Medicine, New Haven, CT 06520, USA
| | - Min-Dian Li
- Department of Comparative Medicine, Department of Cellular and Molecular Physiology, and Yale Center for Molecular and Systems Metabolism, Yale University School of Medicine, New Haven, CT 06520, USA
| | - Xiaoyong Yang
- Department of Comparative Medicine, Department of Cellular and Molecular Physiology, and Yale Center for Molecular and Systems Metabolism, Yale University School of Medicine, New Haven, CT 06520, USA
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10
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Dadhich R, Kapoor S. Lipidomic and Membrane Mechanical Signatures in Triple-Negative Breast Cancer: Scope for Membrane-Based Theranostics. Mol Cell Biochem 2022; 477:2507-2528. [PMID: 35595957 DOI: 10.1007/s11010-022-04459-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2021] [Accepted: 04/28/2022] [Indexed: 10/18/2022]
Abstract
Triple-negative breast cancer (TNBC) is a highly aggressive form of breast cancer associated with poor prognosis, higher grade, and a high rate of metastatic occurrence. Limited therapeutic interventions and the compounding issue of drug resistance in triple-negative breast cancer warrants the discovery of novel therapeutic targets and diagnostic modules. To this view, in addition to proteins, lipids also regulate cellular functions via the formation of membranes that modulate membrane protein function, diffusion, and their localization; thus, orchestrating signaling hot spots enriched in specific lipids/proteins on cell membranes. Lipid deregulation in cancer leads to reprogramming of the membrane dynamics and functions impacting cell proliferation, metabolism, and metastasis, providing exciting starting points for developing lipid-based approaches for treating TNBC. In this review, we provide a detailed account of specific lipidic changes in breast cancer, link the altered lipidome with membrane structure and mechanical properties, and describe how these are linked to subsequent downstream functions implicit in cancer progression, metastasis, and chemoresistance. At the fundamental level, we discuss how the lipid-centric findings in TNBC are providing cues for developing lipid-inspired theranostic strategies while bridging existing gaps in our understanding of the functional involvement of lipid membranes in cancer.
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Affiliation(s)
- Ruchika Dadhich
- Department of Chemistry, Indian Institute of Technology Bombay, Mumbai, 400076, India
| | - Shobhna Kapoor
- Department of Chemistry, Indian Institute of Technology Bombay, Mumbai, 400076, India. .,Graduate School of Integrated Sciences for Life, Hiroshima University, Hiroshima, 739-8528, Japan.
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Sato T, Sassone-Corsi P. Nutrition, metabolism, and epigenetics: pathways of circadian reprogramming. EMBO Rep 2022; 23:e52412. [PMID: 35412705 PMCID: PMC9066069 DOI: 10.15252/embr.202152412] [Citation(s) in RCA: 29] [Impact Index Per Article: 14.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2021] [Revised: 10/28/2021] [Accepted: 03/30/2022] [Indexed: 01/07/2023] Open
Abstract
Food intake profoundly affects systemic physiology. A large body of evidence has indicated a link between food intake and circadian rhythms, and ~24-h cycles are deemed essential for adapting internal homeostasis to the external environment. Circadian rhythms are controlled by the biological clock, a molecular system remarkably conserved throughout evolution. The circadian clock controls the cyclic expression of numerous genes, a regulatory program common to all mammalian cells, which may lead to various metabolic and physiological disturbances if hindered. Although the circadian clock regulates multiple metabolic pathways, metabolic states also provide feedback on the molecular clock. Therefore, a remarkable feature is reprogramming by nutritional challenges, such as a high-fat diet, fasting, ketogenic diet, and caloric restriction. In addition, various factors such as energy balance, histone modifications, and nuclear receptor activity are involved in the remodeling of the clock. Herein, we review the interaction of dietary components with the circadian system and illustrate the relationships linking the molecular clock to metabolism and critical roles in the remodeling process.
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Affiliation(s)
- Tomoki Sato
- Department of Biological Chemistry, Center for Epigenetics and Metabolism, School of Medicine, INSERM U1233, University of California, Irvine, CA, USA
| | - Paolo Sassone-Corsi
- Department of Biological Chemistry, Center for Epigenetics and Metabolism, School of Medicine, INSERM U1233, University of California, Irvine, CA, USA
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12
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Abstract
Post-translational modification with O-linked β-N-acetylglucosamine (O-GlcNAc), a process referred to as O-GlcNAcylation, occurs on a vast variety of proteins. Mounting evidence in the past several decades has clearly demonstrated that O-GlcNAcylation is a unique and ubiquitous modification. Reminiscent of a code, protein O-GlcNAcylation functions as a crucial regulator of nearly all cellular processes studied. The primary aim of this review is to summarize the developments in our understanding of myriad protein substrates modified by O-GlcNAcylation from a systems perspective. Specifically, we provide a comprehensive survey of O-GlcNAcylation in multiple species studied, including eukaryotes (e.g., protists, fungi, plants, Caenorhabditis elegans, Drosophila melanogaster, murine, and human), prokaryotes, and some viruses. We evaluate features (e.g., structural properties and sequence motifs) of O-GlcNAc modification on proteins across species. Given that O-GlcNAcylation functions in a species-, tissue-/cell-, protein-, and site-specific manner, we discuss the functional roles of O-GlcNAcylation on human proteins. We focus particularly on several classes of relatively well-characterized human proteins (including transcription factors, protein kinases, protein phosphatases, and E3 ubiquitin-ligases), with representative O-GlcNAc site-specific functions presented. We hope the systems view of the great endeavor in the past 35 years will help demystify the O-GlcNAc code and lead to more fascinating studies in the years to come.
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Affiliation(s)
- Junfeng Ma
- Department of Oncology, Lombardi Comprehensive Cancer Center, Georgetown University Medical Center, Georgetown University, Washington, DC 20057, United States
| | - Chunyan Hou
- Department of Oncology, Lombardi Comprehensive Cancer Center, Georgetown University Medical Center, Georgetown University, Washington, DC 20057, United States
| | - Ci Wu
- Department of Oncology, Lombardi Comprehensive Cancer Center, Georgetown University Medical Center, Georgetown University, Washington, DC 20057, United States
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13
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Lockridge A, Hanover JA. A nexus of lipid and O-Glcnac metabolism in physiology and disease. Front Endocrinol (Lausanne) 2022; 13:943576. [PMID: 36111295 PMCID: PMC9468787 DOI: 10.3389/fendo.2022.943576] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/13/2022] [Accepted: 07/27/2022] [Indexed: 11/13/2022] Open
Abstract
Although traditionally considered a glucose metabolism-associated modification, the O-linked β-N-Acetylglucosamine (O-GlcNAc) regulatory system interacts extensively with lipids and is required to maintain lipid homeostasis. The enzymes of O-GlcNAc cycling have molecular properties consistent with those expected of broad-spectrum environmental sensors. By direct protein-protein interactions and catalytic modification, O-GlcNAc cycling enzymes may provide both acute and long-term adaptation to stress and other environmental stimuli such as nutrient availability. Depending on the cell type, hyperlipidemia potentiates or depresses O-GlcNAc levels, sometimes biphasically, through a diversity of unique mechanisms that target UDP-GlcNAc synthesis and the availability, activity and substrate selectivity of the glycosylation enzymes, O-GlcNAc Transferase (OGT) and O-GlcNAcase (OGA). At the same time, OGT activity in multiple tissues has been implicated in the homeostatic regulation of systemic lipid uptake, storage and release. Hyperlipidemic patterns of O-GlcNAcylation in these cells are consistent with both transient physiological adaptation and feedback uninhibited obesogenic and metabolic dysregulation. In this review, we summarize the numerous interconnections between lipid and O-GlcNAc metabolism. These links provide insights into how the O-GlcNAc regulatory system may contribute to lipid-associated diseases including obesity and metabolic syndrome.
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14
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Lee SH, Park SY, Choi CS. Insulin Resistance: From Mechanisms to Therapeutic Strategies. Diabetes Metab J 2022; 46:15-37. [PMID: 34965646 PMCID: PMC8831809 DOI: 10.4093/dmj.2021.0280] [Citation(s) in RCA: 197] [Impact Index Per Article: 98.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/12/2021] [Accepted: 12/27/2021] [Indexed: 11/12/2022] Open
Abstract
Insulin resistance is the pivotal pathogenic component of many metabolic diseases, including type 2 diabetes mellitus, and is defined as a state of reduced responsiveness of insulin-targeting tissues to physiological levels of insulin. Although the underlying mechanism of insulin resistance is not fully understood, several credible theories have been proposed. In this review, we summarize the functions of insulin in glucose metabolism in typical metabolic tissues and describe the mechanisms proposed to underlie insulin resistance, that is, ectopic lipid accumulation in liver and skeletal muscle, endoplasmic reticulum stress, and inflammation. In addition, we suggest potential therapeutic strategies for addressing insulin resistance.
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Affiliation(s)
- Shin-Hae Lee
- Korea Mouse Metabolic Phenotyping Center (KMMPC), Lee Gil Ya Cancer and Diabetes Institute, Gachon University, Incheon, Korea
| | - Shi-Young Park
- Korea Mouse Metabolic Phenotyping Center (KMMPC), Lee Gil Ya Cancer and Diabetes Institute, Gachon University, Incheon, Korea
| | - Cheol Soo Choi
- Korea Mouse Metabolic Phenotyping Center (KMMPC), Lee Gil Ya Cancer and Diabetes Institute, Gachon University, Incheon, Korea
- Department of Internal Medicine, Gachon University Gil Medical Center, Incheon, Korea
- Division of Molecular Medicine, Gachon University College of Medicine, Incheon, Korea
- Corresponding author: Cheol Soo Choi https://orcid.org/0000-0001-9627-058X Division of Molecular Medicine, Gachon University College of Medicine, 21 Namdongdaero 774beon-gil, Namdong-gu, Incheon 21565, Korea E-mail:
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15
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Jeong DW, Lee S, Chun YS. How cancer cells remodel lipid metabolism: strategies targeting transcription factors. Lipids Health Dis 2021; 20:163. [PMID: 34775964 PMCID: PMC8590761 DOI: 10.1186/s12944-021-01593-8] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2021] [Accepted: 11/02/2021] [Indexed: 12/30/2022] Open
Abstract
Reprogramming of lipid metabolism has received increasing recognition as a hallmark of cancer cells because lipid dysregulation and the alteration of related enzyme profiles are closely correlated with oncogenic signals and malignant phenotypes, such as metastasis and therapeutic resistance. In this review, we describe recent findings that support the importance of lipids, as well as the transcription factors involved in cancer lipid metabolism. With recent advances in transcription factor analysis, including computer-modeling techniques, transcription factors are emerging as central players in cancer biology. Considering the limited number and the crucial role of transcription factors associated with lipid rewiring in cancers, transcription factor targeting is a promising potential strategy for cancer therapy.
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Affiliation(s)
- Do-Won Jeong
- Department of Biomedical Sciences, Seoul National University College of Medicine, Seoul, 03080, South Korea.,Department of Physiology, Seoul National University College of Medicine, Seoul, 03080, South Korea
| | - Seulbee Lee
- Department of Biomedical Sciences, Seoul National University College of Medicine, Seoul, 03080, South Korea.,Department of Physiology, Seoul National University College of Medicine, Seoul, 03080, South Korea
| | - Yang-Sook Chun
- Department of Biomedical Sciences, Seoul National University College of Medicine, Seoul, 03080, South Korea. .,Department of Physiology, Seoul National University College of Medicine, Seoul, 03080, South Korea. .,Ischemic/Hypoxic Disease Institute, Seoul National University College of Medicine, Seoul, 03080, South Korea.
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16
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Wang D, Yin Z, Ma L, Han L, Chen Y, Pan W, Gong K, Gao Y, Yang X, Chen Y, Han J, Duan Y. Polysaccharide MCP extracted from Morchella esculenta reduces atherosclerosis in LDLR-deficient mice. Food Funct 2021; 12:4842-4854. [PMID: 33950051 DOI: 10.1039/d0fo03475d] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
The pharmaceutical application of fungal polysaccharides has been extensively studied based on their multiple biological activities. However, the effect of Morchella esculenta polysaccharides on the development of atherosclerosis remains unknown. This study aims to investigate the anti-atherosclerotic effect of a novel polysaccharide (MCP) extracted from Morchella esculenta. The average molecular weight of MCP is 1.69 × 105 Da, and it is composed of glucose, mannose and galactose in the molar ratio of 1 : 1.9 : 0.51. LDLR-deficient (LDLR-/-) mice were fed high-fat diet (HFD) and administered intragastrically (i.g.) with saline or MCP dissolved in saline for 15 weeks. We found that MCP inhibited en face and sinus lesions. Moreover, serum levels of total and low-density lipoprotein cholesterol and triglyceride were decreased by MCP. The HFD-induced hepatic lipid accumulation was also attenuated by MCP. The underlying molecular mechanisms of anti-atherogenic and lipogenic effects of MCP might be attributed to reduced cholesterol synthesis by activating AMPKα signaling pathway and inhibiting SREBP2 expression. In addition, MCP-decreased serum triglyceride level is related to inhibiting LXRα expression. Taken together, these results indicate that MCP markedly alleviates atherosclerosis and M. esculenta can be used as a functional food additive to benefit patients with atherosclerosis.
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Affiliation(s)
- Dandan Wang
- Key Laboratory of Metabolism and Regulation for Major Diseases of Anhui Higher Education Institutes, School of Food and Biological Engineering, Hefei University of Technology, Hefei, Anhui, China.
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17
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Loomba R, Friedman SL, Shulman GI. Mechanisms and disease consequences of nonalcoholic fatty liver disease. Cell 2021; 184:2537-2564. [PMID: 33989548 DOI: 10.1016/j.cell.2021.04.015] [Citation(s) in RCA: 825] [Impact Index Per Article: 275.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2020] [Revised: 03/21/2021] [Accepted: 04/09/2021] [Indexed: 02/07/2023]
Abstract
Nonalcoholic fatty liver disease (NAFLD) is the leading chronic liver disease worldwide. Its more advanced subtype, nonalcoholic steatohepatitis (NASH), connotes progressive liver injury that can lead to cirrhosis and hepatocellular carcinoma. Here we provide an in-depth discussion of the underlying pathogenetic mechanisms that lead to progressive liver injury, including the metabolic origins of NAFLD, the effect of NAFLD on hepatic glucose and lipid metabolism, bile acid toxicity, macrophage dysfunction, and hepatic stellate cell activation, and consider the role of genetic, epigenetic, and environmental factors that promote fibrosis progression and risk of hepatocellular carcinoma in NASH.
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Affiliation(s)
- Rohit Loomba
- NAFLD Research Center, Division of Gastroenterology, Department of Medicine, University of California at San Diego, La Jolla, CA 92093, USA.
| | - Scott L Friedman
- Division of Liver Diseases, Department of Medicine, Icahn School of Medicine at Mount Sinai, New York, NY 10029, USA.
| | - Gerald I Shulman
- Departments of Internal Medicine and Cellular & Molecular Physiology, Yale Diabetes Research Center, Yale School of Medicine, New Haven, CT 06520, USA.
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18
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Zhang H, Li Z, Wang Y, Kong Y. O-GlcNAcylation is a key regulator of multiple cellular metabolic pathways. PeerJ 2021. [DOI: 10.7717/peerj.11443] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
O-GlcNAcylation modifies proteins in serine or threonine residues in the nucleus, cytoplasm, and mitochondria. It regulates a variety of cellular biological processes and abnormal O-GlcNAcylation is associated with diabetes, cancer, cardiovascular disease, and neurodegenerative diseases. Recent evidence has suggested that O-GlcNAcylation acts as a nutrient sensor and signal integrator to regulate metabolic signaling, and that dysregulation of its metabolism may be an important indicator of pathogenesis in disease. Here, we review the literature focusing on O-GlcNAcylation regulation in major metabolic processes, such as glucose metabolism, mitochondrial oxidation, lipid metabolism, and amino acid metabolism. We discuss its role in physiological processes, such as cellular nutrient sensing and homeostasis maintenance. O-GlcNAcylation acts as a key regulator in multiple metabolic processes and pathways. Our review will provide a better understanding of how O-GlcNAcylation coordinates metabolism and integrates molecular networks.
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19
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Konzman D, Abramowitz LK, Steenackers A, Mukherjee MM, Na HJ, Hanover JA. O-GlcNAc: Regulator of Signaling and Epigenetics Linked to X-linked Intellectual Disability. Front Genet 2020; 11:605263. [PMID: 33329753 PMCID: PMC7719714 DOI: 10.3389/fgene.2020.605263] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2020] [Accepted: 10/20/2020] [Indexed: 12/13/2022] Open
Abstract
Cellular identity in multicellular organisms is maintained by characteristic transcriptional networks, nutrient consumption, energy production and metabolite utilization. Integrating these cell-specific programs are epigenetic modifiers, whose activity is often dependent on nutrients and their metabolites to function as substrates and co-factors. Emerging data has highlighted the role of the nutrient-sensing enzyme O-GlcNAc transferase (OGT) as an epigenetic modifier essential in coordinating cellular transcriptional programs and metabolic homeostasis. OGT utilizes the end-product of the hexosamine biosynthetic pathway to modify proteins with O-linked β-D-N-acetylglucosamine (O-GlcNAc). The levels of the modification are held in check by the O-GlcNAcase (OGA). Studies from model organisms and human disease underscore the conserved function these two enzymes of O-GlcNAc cycling play in transcriptional regulation, cellular plasticity and mitochondrial reprogramming. Here, we review these findings and present an integrated view of how O-GlcNAc cycling may contribute to cellular memory and transgenerational inheritance of responses to parental stress. We focus on a rare human genetic disorder where mutant forms of OGT are inherited or acquired de novo. Ongoing analysis of this disorder, OGT- X-linked intellectual disability (OGT-XLID), provides a window into how epigenetic factors linked to O-GlcNAc cycling may influence neurodevelopment.
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Affiliation(s)
| | | | | | | | | | - John A. Hanover
- Laboratory of Cellular and Molecular Biology, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, MD, United States
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20
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Chatham JC, Zhang J, Wende AR. Role of O-Linked N-Acetylglucosamine Protein Modification in Cellular (Patho)Physiology. Physiol Rev 2020; 101:427-493. [PMID: 32730113 DOI: 10.1152/physrev.00043.2019] [Citation(s) in RCA: 153] [Impact Index Per Article: 38.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
In the mid-1980s, the identification of serine and threonine residues on nuclear and cytoplasmic proteins modified by a N-acetylglucosamine moiety (O-GlcNAc) via an O-linkage overturned the widely held assumption that glycosylation only occurred in the endoplasmic reticulum, Golgi apparatus, and secretory pathways. In contrast to traditional glycosylation, the O-GlcNAc modification does not lead to complex, branched glycan structures and is rapidly cycled on and off proteins by O-GlcNAc transferase (OGT) and O-GlcNAcase (OGA), respectively. Since its discovery, O-GlcNAcylation has been shown to contribute to numerous cellular functions, including signaling, protein localization and stability, transcription, chromatin remodeling, mitochondrial function, and cell survival. Dysregulation in O-GlcNAc cycling has been implicated in the progression of a wide range of diseases, such as diabetes, diabetic complications, cancer, cardiovascular, and neurodegenerative diseases. This review will outline our current understanding of the processes involved in regulating O-GlcNAc turnover, the role of O-GlcNAcylation in regulating cellular physiology, and how dysregulation in O-GlcNAc cycling contributes to pathophysiological processes.
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Affiliation(s)
- John C Chatham
- Division of Molecular and Cellular Pathology, Department of Pathology, University of Alabama at Birmingham, Birmingham, Alabama; and Birmingham Veterans Affairs Medical Center, Birmingham, Alabama
| | - Jianhua Zhang
- Division of Molecular and Cellular Pathology, Department of Pathology, University of Alabama at Birmingham, Birmingham, Alabama; and Birmingham Veterans Affairs Medical Center, Birmingham, Alabama
| | - Adam R Wende
- Division of Molecular and Cellular Pathology, Department of Pathology, University of Alabama at Birmingham, Birmingham, Alabama; and Birmingham Veterans Affairs Medical Center, Birmingham, Alabama
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21
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Fan Q, Nørgaard RC, Grytten I, Ness CM, Lucas C, Vekterud K, Soedling H, Matthews J, Lemma RB, Gabrielsen OS, Bindesbøll C, Ulven SM, Nebb HI, Grønning-Wang LM, Sæther T. LXRα Regulates ChREBPα Transactivity in a Target Gene-Specific Manner through an Agonist-Modulated LBD-LID Interaction. Cells 2020; 9:cells9051214. [PMID: 32414201 PMCID: PMC7290792 DOI: 10.3390/cells9051214] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2020] [Revised: 04/19/2020] [Accepted: 05/07/2020] [Indexed: 01/02/2023] Open
Abstract
The cholesterol-sensing nuclear receptor liver X receptor (LXR) and the glucose-sensing transcription factor carbohydrate responsive element-binding protein (ChREBP) are central players in regulating glucose and lipid metabolism in the liver. More knowledge of their mechanistic interplay is needed to understand their role in pathological conditions like fatty liver disease and insulin resistance. In the current study, LXR and ChREBP co-occupancy was examined by analyzing ChIP-seq datasets from mice livers. LXR and ChREBP interaction was determined by Co-immunoprecipitation (CoIP) and their transactivity was assessed by real-time quantitative polymerase chain reaction (qPCR) of target genes and gene reporter assays. Chromatin binding capacity was determined by ChIP-qPCR assays. Our data show that LXRα and ChREBPα interact physically and show a high co-occupancy at regulatory regions in the mouse genome. LXRα co-activates ChREBPα and regulates ChREBP-specific target genes in vitro and in vivo. This co-activation is dependent on functional recognition elements for ChREBP but not for LXR, indicating that ChREBPα recruits LXRα to chromatin in trans. The two factors interact via their key activation domains; the low glucose inhibitory domain (LID) of ChREBPα and the ligand-binding domain (LBD) of LXRα. While unliganded LXRα co-activates ChREBPα, ligand-bound LXRα surprisingly represses ChREBPα activity on ChREBP-specific target genes. Mechanistically, this is due to a destabilized LXRα:ChREBPα interaction, leading to reduced ChREBP-binding to chromatin and restricted activation of glycolytic and lipogenic target genes. This ligand-driven molecular switch highlights an unappreciated role of LXRα in responding to nutritional cues that was overlooked due to LXR lipogenesis-promoting function.
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Affiliation(s)
- Qiong Fan
- Department of Molecular Medicine, Institute of Basic Medical Sciences, Faculty of Medicine, University of Oslo, N-0317 Oslo, Norway; (Q.F.); (K.V.); (C.B.)
| | - Rikke Christine Nørgaard
- Department of Nutrition, Institute of Basic Medical Sciences, Faculty of Medicine, University of Oslo, N-0317 Oslo, Norway; (R.C.N.); (C.M.N.); (C.L.); (H.S.); (J.M.); (S.M.U.); (H.I.N.); (L.M.G.-W.)
| | - Ivar Grytten
- Department of Informatics, Faculty of Mathematics and Natural Sciences, University of Oslo, N-0317 Oslo, Norway;
| | - Cecilie Maria Ness
- Department of Nutrition, Institute of Basic Medical Sciences, Faculty of Medicine, University of Oslo, N-0317 Oslo, Norway; (R.C.N.); (C.M.N.); (C.L.); (H.S.); (J.M.); (S.M.U.); (H.I.N.); (L.M.G.-W.)
| | - Christin Lucas
- Department of Nutrition, Institute of Basic Medical Sciences, Faculty of Medicine, University of Oslo, N-0317 Oslo, Norway; (R.C.N.); (C.M.N.); (C.L.); (H.S.); (J.M.); (S.M.U.); (H.I.N.); (L.M.G.-W.)
| | - Kristin Vekterud
- Department of Molecular Medicine, Institute of Basic Medical Sciences, Faculty of Medicine, University of Oslo, N-0317 Oslo, Norway; (Q.F.); (K.V.); (C.B.)
| | - Helen Soedling
- Department of Nutrition, Institute of Basic Medical Sciences, Faculty of Medicine, University of Oslo, N-0317 Oslo, Norway; (R.C.N.); (C.M.N.); (C.L.); (H.S.); (J.M.); (S.M.U.); (H.I.N.); (L.M.G.-W.)
| | - Jason Matthews
- Department of Nutrition, Institute of Basic Medical Sciences, Faculty of Medicine, University of Oslo, N-0317 Oslo, Norway; (R.C.N.); (C.M.N.); (C.L.); (H.S.); (J.M.); (S.M.U.); (H.I.N.); (L.M.G.-W.)
| | - Roza Berhanu Lemma
- Department of Biosciences, Faculty of Mathematics and Natural Sciences, University of Oslo, N-0317 Oslo, Norway; (R.B.L.); (O.S.G.)
| | - Odd Stokke Gabrielsen
- Department of Biosciences, Faculty of Mathematics and Natural Sciences, University of Oslo, N-0317 Oslo, Norway; (R.B.L.); (O.S.G.)
| | - Christian Bindesbøll
- Department of Molecular Medicine, Institute of Basic Medical Sciences, Faculty of Medicine, University of Oslo, N-0317 Oslo, Norway; (Q.F.); (K.V.); (C.B.)
| | - Stine Marie Ulven
- Department of Nutrition, Institute of Basic Medical Sciences, Faculty of Medicine, University of Oslo, N-0317 Oslo, Norway; (R.C.N.); (C.M.N.); (C.L.); (H.S.); (J.M.); (S.M.U.); (H.I.N.); (L.M.G.-W.)
| | - Hilde Irene Nebb
- Department of Nutrition, Institute of Basic Medical Sciences, Faculty of Medicine, University of Oslo, N-0317 Oslo, Norway; (R.C.N.); (C.M.N.); (C.L.); (H.S.); (J.M.); (S.M.U.); (H.I.N.); (L.M.G.-W.)
| | - Line Mariann Grønning-Wang
- Department of Nutrition, Institute of Basic Medical Sciences, Faculty of Medicine, University of Oslo, N-0317 Oslo, Norway; (R.C.N.); (C.M.N.); (C.L.); (H.S.); (J.M.); (S.M.U.); (H.I.N.); (L.M.G.-W.)
| | - Thomas Sæther
- Department of Molecular Medicine, Institute of Basic Medical Sciences, Faculty of Medicine, University of Oslo, N-0317 Oslo, Norway; (Q.F.); (K.V.); (C.B.)
- Correspondence: ; Tel.: +47-22-851510
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Bindesbøll C, Aas A, Ogmundsdottir MH, Pankiv S, Reine T, Zoncu R, Simonsen A. NBEAL1 controls SREBP2 processing and cholesterol metabolism and is a susceptibility locus for coronary artery disease. Sci Rep 2020; 10:4528. [PMID: 32161285 PMCID: PMC7066131 DOI: 10.1038/s41598-020-61352-0] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2019] [Accepted: 02/21/2020] [Indexed: 01/24/2023] Open
Abstract
Dysregulated cholesterol homeostasis promotes the pathology of atherosclerosis, myocardial infarction and strokes. Cellular cholesterol is mainly regulated at the transcriptional level by SREBP2, but also through uptake of extracellular cholesterol from low density lipoproteins (LDL) via expression of LDL receptors (LDLR) at the cell surface. Identification of the mechanisms involved in regulation of these processes are thus key to understand the pathology of coronary artery disease. Here, we identify the large and poorly characterized BEACH domain protein Neurobeachin-like (NBEAL) 1 as a Golgi- associated protein required for regulation of cholesterol metabolism. NBEAL1 is most abundantly expressed in arteries. Genetic variants in NBEAL1 are associated with decreased expression of NBEAL1 in arteries and increased risk of coronary artery disease in humans. We show that NBEAL1 regulates cholesterol metabolism by modulating LDLR expression in a mechanism involving interaction with SCAP and PAQR3 and subsequent SREBP2-processing. Thus, low expression of NBEAL1 may lead to increased risk of coronary artery disease by downregulation of LDLR levels.
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Affiliation(s)
- Christian Bindesbøll
- Department of Molecular Medicine, Institute of Basic Medical Sciences and Centre for Cancer Cell Reprogramming, Institute of Clinical Medicine, Faculty of Medicine, University of Oslo, 1112 Blindern, 0317, Oslo, Norway.
| | - Aleksander Aas
- Department of Molecular Medicine, Institute of Basic Medical Sciences and Centre for Cancer Cell Reprogramming, Institute of Clinical Medicine, Faculty of Medicine, University of Oslo, 1112 Blindern, 0317, Oslo, Norway
| | - Margret Helga Ogmundsdottir
- Department of Biochemistry and Molecular Biology, Biomedical Center, Faculty of Medicine, University of Iceland, Vatnsmyrarvegur 16, 101, Reykjavik, Iceland
| | - Serhiy Pankiv
- Department of Molecular Medicine, Institute of Basic Medical Sciences and Centre for Cancer Cell Reprogramming, Institute of Clinical Medicine, Faculty of Medicine, University of Oslo, 1112 Blindern, 0317, Oslo, Norway
| | - Trine Reine
- Department of Nutrition, Institute of Basic Medical Sciences, University of Oslo, 1112 Blindern, 0317, Oslo, Norway.,Section for Interphase genetics, Institute for Cancer Genetics and Informatics, Oslo University Hospital, 0424, Oslo, Norway
| | - Roberto Zoncu
- Department of Molecular and Cell Biology, University of California, Berkeley, Berkeley, CA, 94720, USA
| | - Anne Simonsen
- Department of Molecular Medicine, Institute of Basic Medical Sciences and Centre for Cancer Cell Reprogramming, Institute of Clinical Medicine, Faculty of Medicine, University of Oslo, 1112 Blindern, 0317, Oslo, Norway.
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Effects of Moderate Chronic Food Restriction on the Development of Postprandial Dyslipidemia with Ageing. Nutrients 2019; 11:nu11081865. [PMID: 31405194 PMCID: PMC6723802 DOI: 10.3390/nu11081865] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2019] [Revised: 08/01/2019] [Accepted: 08/07/2019] [Indexed: 02/02/2023] Open
Abstract
Ageing is a major risk factor for the development of metabolic disorders linked to dyslipidemia, usually accompanied by increased adiposity. The goal of this work was to investigate whether avoiding an excessive increase in adiposity with ageing, via moderate chronic food restriction (FR), ameliorates postprandial dyslipidemia in a rat model of metabolic syndrome associated with ageing. Accordingly, we performed an oral lipid loading test (OLLT) in mature middle-aged (7 months) and middle-old-aged (24 months) Wistar rats fed ad libitum (AL) or under moderate FR for 3 months. Briefly, overnight fasted rats were orally administered a bolus of extra-virgin olive oil (1 mL/Kg of body weight) and blood samples were taken from the tail vein before fat load (t = 0) and 30, 60, 90, 120, 180, and 240 min after fat administration. Changes in serum lipids, glucose, insulin, and glucagon levels were measured at different time-points. Expression of liver and adipose tissue metabolic genes were also determined before (t = 0) and after the fat load (t = 240 min). Postprandial dyslipidemia progressively increased with ageing and this could be associated with hepatic ChREBP activity. Interestingly, moderate chronic FR reduced adiposity and avoided excessive postprandial hypertriglyceridemia in 7- and 24-month-old Wistar rats, strengthening the association between postprandial triglyceride levels and adiposity. The 24-month-old rats needed more insulin to maintain postprandial normoglycemia; nevertheless, hyperglycemia occurred at 240 min after fat administration. FR did not alter the fasted serum glucose levels but it markedly decreased glucagon excursion during the OLLT and the postprandial rise of glycemia in the 24-month-old rats, and FGF21 in the 7-month-old Wistar rats. Hence, our results pointed to an important role of FR in postprandial energy metabolism and insulin resistance in ageing. Lastly, our data support the idea that the vWAT might function as an ectopic site for fat deposition in 7-month-old and in 24-month-old Wistar rats that could increase their browning capacity in response to an acute fat load.
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Itaba N, Noda I, Oka H, Kono Y, Okinaka K, Yokobata T, Okazaki S, Morimoto M, Shiota G. Hepatic cell sheets engineered from human mesenchymal stem cells with a single small molecule compound IC-2 ameliorate acute liver injury in mice. Regen Ther 2018; 9:45-57. [PMID: 30525075 PMCID: PMC6222293 DOI: 10.1016/j.reth.2018.07.001] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2018] [Revised: 06/22/2018] [Accepted: 07/02/2018] [Indexed: 01/31/2023] Open
Abstract
INTRODUCTION We previously reported that transplantation of hepatic cell sheets from human bone marrow-derived mesenchymal stem cells (BM-MSCs) with hexachlorophene, a Wnt/β-catenin signaling inhibitor, ameliorated acute liver injury. In a further previous report, we identified IC-2, a newly synthesized derivative of the Wnt/β-catenin signaling inhibitor ICG-001, as a potent inducer of hepatic differentiation of BM-MSCs. METHODS We manufactured hepatic cell sheets by engineering from human BM-MSCs using the single small molecule IC-2. The therapeutic potential of IC-2-induced hepatic cell sheets was assessed by transplantation of IC-2- and hexachlorophene-treated hepatic cell sheets using a mouse model of acute liver injury. RESULTS Significant improvement of liver injury was elicited by the IC-2-treated hepatic cell sheets. The expression of complement C3 was enhanced by IC-2, followed by prominent hepatocyte proliferation stimulated through the activation of NF-κB and its downstream molecule STAT-3. Indeed, IC-2 also enhanced the expression of amphiregulin, resulting in the activation of the EGFR pathway and further stimulation of hepatocyte proliferation. As another important therapeutic mechanism, we revealed prominent reduction of oxidative stress mediated through upregulation of the thioredoxin (TRX) system by IC-2-treated hepatic cell sheets. The effects mediated by IC-2-treated sheets were superior compared with those mediated by hexachlorophene-treated sheets. CONCLUSION The single compound IC-2 induced hepatic cell sheets that possess potent regeneration capacity and ameliorate acute liver injury.
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Key Words
- 8-OHdG, 8-hydroxydeoxyguanosine
- A1AT, α1-antitrypsin
- ALT, alanine aminotransferase
- APOE, apolipoprotein E
- AREG, amphiregulin
- AST, aspartate aminotransferase
- Acute liver failure
- BM-MSCs, bone marrow-derived mesenchymal stem cells
- C3, complement C3
- C4A, complement C4A
- C5aR, complement C5a receptor
- CBP, CREB-binding protein
- CCl4, carbon tetrachloride
- CP, ceruloplasmin
- ChREBP, Carbohydrate-responsive element-binding protein
- ChoREs, carbohydrate response elements
- DMSO, dimethyl sulfoxide
- EGFR, epidermal growth factor receptor
- ERK, extracellular signal-regulated kinase
- GPX, glutathione peroxidase
- GR, Glutathione reductase
- GRX, glutaredoxin
- GSH, glutathione
- HB-EGF, heparin binding-epidermal growth factor-like growth factor
- HGFR, hepatocyte growth factor receptor
- Hepatic cell sheets
- IL-1ra, interleukin-1 receptor antagonist
- IL-6, interleukin-6
- LXR, liver X receptor
- Liver regeneration
- MDA, malondialdehyde
- Mesenchymal stem cells
- NF-κB, nuclear factor-kappa B
- PCNA, proliferating cell nuclear antigen
- PRX, peroxiredoxin
- RBP4, retinol binding protein 4
- SOD, superoxide dismutase
- STAT-3, Signal Tranducer and Activator of Transcription 3
- TF, transferrin
- TGFα, transforming growth factor alpha
- TNFα, tumor necrosis factor alpha
- TRX, thioredoxin
- TRXR, thioredoxin reductase
- Wnt/β-catenin signal inhibitor
- hGAPDH, human glyceraldehyde 3-phosphate dehydrogenase
- mActb, mouse actin, beta
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Affiliation(s)
- Noriko Itaba
- Division of Molecular and Genetic Medicine, Graduate School of Medicine, Tottori University, 86 Nishi-cho, Yonago, Tottori 683-8503, Japan
| | - Ikuya Noda
- Division of Molecular and Genetic Medicine, Graduate School of Medicine, Tottori University, 86 Nishi-cho, Yonago, Tottori 683-8503, Japan
| | - Hiroyuki Oka
- Research Initiative Center, Tottori University, 4-101 Koyama, Tottori 680-8550, Japan
| | - Yohei Kono
- Division of Molecular and Genetic Medicine, Graduate School of Medicine, Tottori University, 86 Nishi-cho, Yonago, Tottori 683-8503, Japan
| | - Kaori Okinaka
- Division of Molecular and Genetic Medicine, Graduate School of Medicine, Tottori University, 86 Nishi-cho, Yonago, Tottori 683-8503, Japan
| | - Tsuyoshi Yokobata
- Division of Molecular and Genetic Medicine, Graduate School of Medicine, Tottori University, 86 Nishi-cho, Yonago, Tottori 683-8503, Japan
| | - Shizuma Okazaki
- Division of Molecular and Genetic Medicine, Graduate School of Medicine, Tottori University, 86 Nishi-cho, Yonago, Tottori 683-8503, Japan
| | - Minoru Morimoto
- Research Initiative Center, Tottori University, 4-101 Koyama, Tottori 680-8550, Japan
| | - Goshi Shiota
- Division of Molecular and Genetic Medicine, Graduate School of Medicine, Tottori University, 86 Nishi-cho, Yonago, Tottori 683-8503, Japan
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25
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O-GlcNAc site-mapping of liver X receptor-α and O-GlcNAc transferase. Biochem Biophys Res Commun 2018; 499:354-360. [PMID: 29577901 DOI: 10.1016/j.bbrc.2018.03.164] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2018] [Accepted: 03/21/2018] [Indexed: 01/17/2023]
Abstract
The Liver X Receptor α (LXRα) belongs to the nuclear receptor superfamily and plays an essential role in regulating cholesterol, lipid and glucose metabolism and inflammatory responses. We have previously shown that LXRα is post-translationally modified by O-linked β-N-acetyl-glucosamine (O-GlcNAc) with increased transcriptional activity. Moreover, we showed that LXRα associates with O-GlcNAc transferase (OGT) in vitro and in vivo in mouse liver. In this study, we report that human LXRα is O-GlcNAc modified in its N-terminal domain (NTD) by identifying a specific O-GlcNAc site S49 and a novel O-GlcNAc modified peptide 20LWKPGAQDASSQAQGGSSCILRE42. However, O-GlcNAc site-mutations did not modulate LXRα transactivation of selected target gene promoters in vitro. Peptide array and co-immunoprecipitation assays demonstrate that LXRα interacts with OGT in its NTD and ligand-binding domain (LBD) in a ligand-independent fashion. Moreover, we map two new O-GlcNAc sites in the longest OGT isoform (ncOGT): S437 in the tetratricopeptide repeat (TPR) 13 domain and T1043 in the far C-terminus, and a new O-GlcNAc modified peptide (amino acids 826-832) in the intervening region (Int-D) within the catalytic domain. We also map four new O-GlcNAc sites in the short isoform sOGT: S391, T393, S399 and S437 in the TPRs 11-13 domain. Future studies will reveal the biological role of identified O-GlcNAc sites in LXRα and OGT.
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26
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Koenig AB, Barajas JM, Guerrero MJ, Ghoshal K. A Comprehensive Analysis of Argonaute-CLIP Data Identifies Novel, Conserved and Species-Specific Targets of miR-21 in Human Liver and Hepatocellular Carcinoma. Int J Mol Sci 2018; 19:E851. [PMID: 29538313 PMCID: PMC5877712 DOI: 10.3390/ijms19030851] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2018] [Revised: 03/08/2018] [Accepted: 03/13/2018] [Indexed: 12/16/2022] Open
Abstract
MicroRNAs are ~22 nucleotide RNAs that regulate gene expression at the post-transcriptional level by binding messenger RNA transcripts. miR-21 is described as an oncomiR whose steady-state levels are commonly increased in many malignancies, including hepatocellular carcinoma (HCC). Methods known as cross-linking and immunoprecipitation of RNA followed by sequencing (CLIP-seq) have enabled transcriptome-wide identification of miRNA interactomes. In our study, we use a publicly available Argonaute-CLIP dataset (GSE97061), which contains nine HCC cases with matched benign livers, to characterize the miR-21 interactome in HCC. Argonaute-CLIP identified 580 miR-21 bound target sites on coding transcripts, of which 332 were located in the coding sequences, 214 in the 3'-untranslated region, and 34 in the 5'-untranslated region, introns, or downstream sequences. We compared the expression of miR-21 targets in 377 patients with liver cancer from the data generated by The Cancer Genome Atlas (TCGA) and found that mRNA levels of 402 miR-21 targets are altered in HCC. Expression of three novel predicted miR-21 targets (CAMSAP1, DDX1 and MARCKSL1) correlated with HCC patient survival. Analysis of RNA-seq data from SK-Hep1 cells treated with a miR-21 antisense oligonucleotide (GSE65892) identified RMND5A, an E3 ubiquitin ligase, as a strong miR-21 candidate target. Collectively, our analysis identified novel miR-21 targets that are likely to play a causal role in hepatocarcinogenesis.
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Affiliation(s)
- Aaron Balasingam Koenig
- Department of Pathology, Comprehensive Cancer Center, The Ohio State University, Columbus, OH 43210, USA.
- Medical Student Research Program, The Ohio State University College of Medicine, Columbus, OH 43210, USA.
| | - Juan Martín Barajas
- Department of Pathology, Comprehensive Cancer Center, The Ohio State University, Columbus, OH 43210, USA.
| | - María Jose Guerrero
- Department of Pathology, Comprehensive Cancer Center, The Ohio State University, Columbus, OH 43210, USA.
| | - Kalpana Ghoshal
- Department of Pathology, Comprehensive Cancer Center, The Ohio State University, Columbus, OH 43210, USA.
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27
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Samuel VT, Shulman GI. Nonalcoholic Fatty Liver Disease as a Nexus of Metabolic and Hepatic Diseases. Cell Metab 2018; 27:22-41. [PMID: 28867301 PMCID: PMC5762395 DOI: 10.1016/j.cmet.2017.08.002] [Citation(s) in RCA: 452] [Impact Index Per Article: 75.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/30/2017] [Revised: 07/01/2017] [Accepted: 08/01/2017] [Indexed: 12/15/2022]
Abstract
NAFLD is closely linked with hepatic insulin resistance. Accumulation of hepatic diacylglycerol activates PKC-ε, impairing insulin receptor activation and insulin-stimulated glycogen synthesis. Peripheral insulin resistance indirectly influences hepatic glucose and lipid metabolism by increasing flux of substrates that promote lipogenesis (glucose and fatty acids) and gluconeogenesis (glycerol and fatty acid-derived acetyl-CoA, an allosteric activator of pyruvate carboxylase). Weight loss with diet or bariatric surgery effectively treats NAFLD, but drugs specifically approved for NAFLD are not available. Some new pharmacological strategies act broadly to alter energy balance or influence pathways that contribute to NAFLD (e.g., agonists for PPAR γ, PPAR α/δ, FXR and analogs for FGF-21, and GLP-1). Others specifically inhibit key enzymes involved in lipid synthesis (e.g., mitochondrial pyruvate carrier, acetyl-CoA carboxylase, stearoyl-CoA desaturase, and monoacyl- and diacyl-glycerol transferases). Finally, a novel class of liver-targeted mitochondrial uncoupling agents increases hepatocellular energy expenditure, reversing the metabolic and hepatic complications of NAFLD.
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Affiliation(s)
- Varman T Samuel
- Department of Medicine, Yale University School of Medicine, New Haven, CT 06510, USA; Veterans Affairs Medical Center, West Haven, CT 06516, USA.
| | - Gerald I Shulman
- Department of Medicine, Yale University School of Medicine, New Haven, CT 06510, USA; Department of Cellular and Molecular Physiology, Yale University School of Medicine, New Haven, CT 06510, USA; Howard Hughes Medical Institute, Yale University School of Medicine, New Haven, CT 06510, USA.
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28
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Velliquette RA, Rajgopal A, Rebhun J, Glynn K. Lithospermum erythrorhizon Root and its Naphthoquinones Repress SREBP1c and Activate PGC1α Through AMPKα. Obesity (Silver Spring) 2018; 26:126-134. [PMID: 29165897 DOI: 10.1002/oby.22061] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/30/2017] [Revised: 09/29/2017] [Accepted: 09/29/2017] [Indexed: 01/06/2023]
Abstract
OBJECTIVE To examine specific molecular mechanisms involved in modulating hepatic lipogenesis and mitochondria biogenesis signals by Lithospermum erythrorhizon (gromwell) root extract. METHODS Stable cell lines with luciferase reporter constructs were generated to examine sterol regulatory element binding protein 1c (SREBP1c) and peroxisome proliferator-activated receptor gamma, coactivator 1 (PGC1) α promoter activity and estrogen-related receptor (ERR) α response element activity. Gene expression of SREBP1c, stearoyl coenzyme A desaturase 1, and PGC1α was measured by using reverse transcription polymerase chain reaction. Lipogenesis was measured in human hepatoma cells with Nile red staining and flow cytometry. Phosphorylation of AMP-activated protein kinase (AMPK) α was determined by using ELISA and Western blot. RESULTS Gromwell root extract and its naphthoquinones dose-dependently repressed high glucose and liver X receptor α induction of SREBP1c promoter activity and gene expression. Hepatic lipogenesis was repressed, and PGC1α promoter and gene expression and ERRα response element activity were increased by gromwell root extract. Gromwell root extract, shikonin, and α-methyl-n-butyrylshikonin increased AMPKα phosphorylation, and inhibition of AMPK blunted the repression in SREBP1c promoter activity by gromwell root extract and its naphthoquinones. CONCLUSIONS Data suggest that gromwell root extract and its naphthoquinones repress lipogenesis by increasing the phosphorylated state of AMPKα and stimulating mitochondrial biogenesis signals.
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Affiliation(s)
| | | | - John Rebhun
- Amway Research and Development, Ada, Michigan, USA
| | - Kelly Glynn
- Amway Research and Development, Ada, Michigan, USA
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29
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Kim MJ, Choi MY, Lee DH, Roh GS, Kim HJ, Kang SS, Cho GJ, Kim YS, Choi WS. O-linked N-acetylglucosamine transferase enhances secretory clusterin expression via liver X receptors and sterol response element binding protein regulation in cervical cancer. Oncotarget 2017; 9:4625-4636. [PMID: 29435130 PMCID: PMC5797001 DOI: 10.18632/oncotarget.23588] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2017] [Accepted: 12/04/2017] [Indexed: 01/09/2023] Open
Abstract
O-linked N-acetylglucosamine transferase (OGT) expression is increased in various cancer types, indicating the potential importance of O-GlcNAcylation in tumorigenesis. Secretory clusterin (sCLU) is involved in cancer cell proliferation and drug resistance, and recently, liver X receptors (LXRs) and sterol response element binding protein-1 (SREBP-1) were reported to regulate sCLU transcription. Here, we found that sCLU is significantly increased in cervical cancer cell lines, which have higher expression levels of O-GlcNAc and OGT than keratinocytes. OGT knockdown decreased expression of LXRs, SREBP-1 and sCLU through hypo-O-GlcNAcylation of LXRs. Additionally, treatment with Thiamet G, O-GlcNAcase OGA inhibitor, increased expression of O-GlcNAcylation and sCLU, and high glucose increased levels of LXRs, SREBP-1 and sCLU in HeLa cells. Moreover, OGT knockdown induced G0/G1 phase cell cycle arrest and late apoptosis in cisplatin-treated HeLa cells, and decreased viability compared to OGT intact HeLa cells. Taken together, these findings suggest that OGT, O-GlcNAcylated LXRs, and SREBP-1 increase sCLU expression in cervical cancer cells, which contributes to drug resistance.
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Affiliation(s)
- Min Jun Kim
- Department of Anatomy and Convergence Medical Science, Institute of Health Sciences, College of Medicine, Gyeongsang National University, Jinju, Gyeongnam, Republic of Korea
| | - Mee Young Choi
- Department of Anatomy and Convergence Medical Science, Institute of Health Sciences, College of Medicine, Gyeongsang National University, Jinju, Gyeongnam, Republic of Korea
| | - Dong Hoon Lee
- Department of Anatomy and Convergence Medical Science, Institute of Health Sciences, College of Medicine, Gyeongsang National University, Jinju, Gyeongnam, Republic of Korea
| | - Gu Seob Roh
- Department of Anatomy and Convergence Medical Science, Institute of Health Sciences, College of Medicine, Gyeongsang National University, Jinju, Gyeongnam, Republic of Korea
| | - Hyun Joon Kim
- Department of Anatomy and Convergence Medical Science, Institute of Health Sciences, College of Medicine, Gyeongsang National University, Jinju, Gyeongnam, Republic of Korea
| | - Sang Soo Kang
- Department of Anatomy and Convergence Medical Science, Institute of Health Sciences, College of Medicine, Gyeongsang National University, Jinju, Gyeongnam, Republic of Korea
| | - Gyeong Jae Cho
- Department of Anatomy and Convergence Medical Science, Institute of Health Sciences, College of Medicine, Gyeongsang National University, Jinju, Gyeongnam, Republic of Korea
| | - Yoon Sook Kim
- Department of Anatomy and Convergence Medical Science, Institute of Health Sciences, College of Medicine, Gyeongsang National University, Jinju, Gyeongnam, Republic of Korea
| | - Wan Sung Choi
- Department of Anatomy and Convergence Medical Science, Institute of Health Sciences, College of Medicine, Gyeongsang National University, Jinju, Gyeongnam, Republic of Korea
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30
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Abstract
Cellular lipid metabolism and homeostasis are controlled by sterol regulatory-element binding proteins (SREBPs). In addition to performing canonical functions in the transcriptional regulation of genes involved in the biosynthesis and uptake of lipids, genome-wide system analyses have revealed that these versatile transcription factors act as important nodes of convergence and divergence within biological signalling networks. Thus, they are involved in myriad physiological and pathophysiological processes, highlighting the importance of lipid metabolism in biology. Changes in cell metabolism and growth are reciprocally linked through SREBPs. Anabolic and growth signalling pathways branch off and connect to multiple steps of SREBP activation and form complex regulatory networks. In addition, SREBPs are implicated in numerous pathogenic processes such as endoplasmic reticulum stress, inflammation, autophagy and apoptosis, and in this way, they contribute to obesity, dyslipidaemia, diabetes mellitus, nonalcoholic fatty liver disease, nonalcoholic steatohepatitis, chronic kidney disease, neurodegenerative diseases and cancers. This Review aims to provide a comprehensive understanding of the role of SREBPs in physiology and pathophysiology at the cell, organ and organism levels.
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Affiliation(s)
- Hitoshi Shimano
- Department of Internal Medicine (Endocrinology and Metabolism), Faculty of Medicine, University of Tsukuba, Tsukuba, Ibaraki 305-8575, Japan
- International Institute for Integrative Sleep Medicine (WPI-IIIS), University of Tsukuba, Tsukuba, Ibaraki 305-8575, Japan
- Life Science Center, Tsukuba Advanced Research Alliance (TARA), University of Tsukuba, Tsukuba 305-8577, Japan
- AMED-CREST, Japan Agency for Medical Research and Development, Chiyoda-ku, Tokyo 100-0004, Japan
| | - Ryuichiro Sato
- AMED-CREST, Japan Agency for Medical Research and Development, Chiyoda-ku, Tokyo 100-0004, Japan
- Department of Applied Biological Chemistry, Graduate School of Agricultural and Life Sciences, The University of Tokyo, Bunkyo, Tokyo 113-8657, Japan
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31
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Ter Horst KW, Serlie MJ. Fructose Consumption, Lipogenesis, and Non-Alcoholic Fatty Liver Disease. Nutrients 2017; 9:E981. [PMID: 28878197 PMCID: PMC5622741 DOI: 10.3390/nu9090981] [Citation(s) in RCA: 183] [Impact Index Per Article: 26.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2017] [Revised: 08/25/2017] [Accepted: 09/04/2017] [Indexed: 02/07/2023] Open
Abstract
Increased fructose consumption has been suggested to contribute to non-alcoholic fatty liver disease (NAFLD), dyslipidemia, and insulin resistance, but a causal role of fructose in these metabolic diseases remains debated. Mechanistically, hepatic fructose metabolism yields precursors that can be used for gluconeogenesis and de novo lipogenesis (DNL). Fructose-derived precursors also act as nutritional regulators of the transcription factors, including ChREBP and SREBP1c, that regulate the expression of hepatic gluconeogenesis and DNL genes. In support of these mechanisms, fructose intake increases hepatic gluconeogenesis and DNL and raises plasma glucose and triglyceride levels in humans. However, epidemiological and fructose-intervention studies have had inconclusive results with respect to liver fat, and there is currently no good human evidence that fructose, when consumed in isocaloric amounts, causes more liver fat accumulation than other energy-dense nutrients. In this review, we aim to provide an overview of the seemingly contradicting literature on fructose and NAFLD. We outline fructose physiology, the mechanisms that link fructose to NAFLD, and the available evidence from human studies. From this framework, we conclude that the cellular mechanisms underlying hepatic fructose metabolism will likely reveal novel targets for the treatment of NAFLD, dyslipidemia, and hepatic insulin resistance. Finally, fructose-containing sugars are a major source of excess calories, suggesting that a reduction of their intake has potential for the prevention of NAFLD and other obesity-related diseases.
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Affiliation(s)
- Kasper W Ter Horst
- Department of Endocrinology and Metabolism, Academic Medical Center, Meibergdreef 9, 1105AZ Amsterdam, The Netherlands.
| | - Mireille J Serlie
- Department of Endocrinology and Metabolism, Academic Medical Center, Meibergdreef 9, 1105AZ Amsterdam, The Netherlands.
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32
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Ducheix S, Montagner A, Polizzi A, Lasserre F, Régnier M, Marmugi A, Benhamed F, Bertrand-Michel J, Mselli-Lakhal L, Loiseau N, Martin PG, Lobaccaro JM, Ferrier L, Postic C, Guillou H. Dietary oleic acid regulates hepatic lipogenesis through a liver X receptor-dependent signaling. PLoS One 2017; 12:e0181393. [PMID: 28732092 PMCID: PMC5521785 DOI: 10.1371/journal.pone.0181393] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2017] [Accepted: 06/22/2017] [Indexed: 12/13/2022] Open
Abstract
Olive oil consumption is beneficial for health as it is associated with a decreased prevalence of cancer and cardiovascular diseases. Oleic acid is, by far, the most abundant component of olive oil. Since it can be made through de novo synthesis in animals, it is not an essential fatty acid. While it has become clear that dietary oleic acid regulates many biological processes, the signaling pathway involved in these regulations remains poorly defined. In this work we tested the impact of an oleic acid-rich diet on hepatic gene expression. We were particularly interested in addressing the contribution of Liver X Receptors (LXR) in the control of genes involved in hepatic lipogenesis, an essential process in whole body energy homeostasis. We used wild-type mice and transgenic mice deficient for both α and β Liver X Receptor isoforms (LXR-/-) fed a control or an oleate enriched diet. We observed that hepatic-lipid accumulation was enhanced as well as the expression of lipogenic genes in the liver of wild-type mice fed the oleate enriched diet. In contrast, none of these changes occurred in the liver of LXR-/- mice. Strikingly, oleate-rich diet reduced cholesterolemia in wild-type mice and induced signs of liver inflammation and damage in LXR-/- mice but not in wild-type mice. This work suggests that dietary oleic acid reduces cholesterolemia while promoting LXR-dependent hepatic lipogenesis without detrimental effects to the liver.
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Affiliation(s)
- Simon Ducheix
- INRA, ToxAlim, Toulouse, France.,Université de Toulouse, INP, UPS, ToxAlim, Toulouse, France
| | - Alexandra Montagner
- INRA, ToxAlim, Toulouse, France.,Université de Toulouse, INP, UPS, ToxAlim, Toulouse, France
| | - Arnaud Polizzi
- INRA, ToxAlim, Toulouse, France.,Université de Toulouse, INP, UPS, ToxAlim, Toulouse, France
| | - Frédéric Lasserre
- INRA, ToxAlim, Toulouse, France.,Université de Toulouse, INP, UPS, ToxAlim, Toulouse, France
| | - Marion Régnier
- INRA, ToxAlim, Toulouse, France.,Université de Toulouse, INP, UPS, ToxAlim, Toulouse, France
| | - Alice Marmugi
- INRA, ToxAlim, Toulouse, France.,Université de Toulouse, INP, UPS, ToxAlim, Toulouse, France
| | - Fadila Benhamed
- INSERM, U1016, Institut Cochin, Paris, France.,CNRS, UMR8104, Paris, France
| | | | - Laila Mselli-Lakhal
- INRA, ToxAlim, Toulouse, France.,Université de Toulouse, INP, UPS, ToxAlim, Toulouse, France
| | - Nicolas Loiseau
- INRA, ToxAlim, Toulouse, France.,Université de Toulouse, INP, UPS, ToxAlim, Toulouse, France
| | - Pascal G Martin
- INRA, ToxAlim, Toulouse, France.,Université de Toulouse, INP, UPS, ToxAlim, Toulouse, France
| | - Jean-Marc Lobaccaro
- Clermont Université, Université Blaise Pascal, Génétique Reproduction et Développement, Clermont-Ferrand, France.,CNRS, UMR 6293, GReD, Aubière, France.,INSERM, U1103, GReD, Aubière, France.,Centre de Recherche en Nutrition Humaine d'Auvergne, Clermont-Ferrand, France
| | - Laurent Ferrier
- INRA, ToxAlim, Toulouse, France.,Université de Toulouse, INP, UPS, ToxAlim, Toulouse, France
| | - Catherine Postic
- INSERM, U1016, Institut Cochin, Paris, France.,CNRS, UMR8104, Paris, France.,Université Paris Descartes, Sorbonne Paris Cité, Paris, France
| | - Hervé Guillou
- INRA, ToxAlim, Toulouse, France.,Université de Toulouse, INP, UPS, ToxAlim, Toulouse, France
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33
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LXRα Regulates Hepatic ChREBPα Activity and Lipogenesis upon Glucose, but Not Fructose Feeding in Mice. Nutrients 2017; 9:nu9070678. [PMID: 28661453 PMCID: PMC5537793 DOI: 10.3390/nu9070678] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2017] [Revised: 06/15/2017] [Accepted: 06/26/2017] [Indexed: 12/16/2022] Open
Abstract
Liver X receptors (LXRα/β) and carbohydrate response element-binding proteins (ChREBPα/β) are key players in the transcriptional control of hepatic de novo lipogenesis. LXRα/β double knockout (LXRα−/−/β−/−) mice have reduced feeding-induced nuclear O-linked N-acetylglucosamine (O-GlcNAc) signaling, ChREBPα activity, and lipogenic gene expression in livers, suggesting important roles for LXRs in linking hepatic glucose utilization to lipid synthesis. However, the role of LXRs in fructose-induced ChREBP activation and lipogenesis is currently unknown. In this study, we studied the effects of high fructose or high glucose feeding on hepatic carbohydrate metabolism and lipogenic gene expression in livers from fasted (24 h) and fasted-refed (12 h) wild type and LXRα knockout (LXRα−/−) mice. Hepatic lipogenic gene expression was reduced in glucose fed, but not fructose fed LXRα−/− mice. This was associated with lower expression of liver pyruvate-kinase (L-pk) and Chrebpβ, indicating reduced ChREBPα activity in glucose fed, but not fructose fed mice. Interestingly, ChREBP binding to the L-pk promoter was increased in fructose fed LXRα−/− mice, concomitant with increased glucose-6-phosphatase (G6pc) expression and O-GlcNAc modified LXRβ, suggesting a role for LXRβ in regulating ChREBPα activity upon fructose feeding. In conclusion, we propose that LXRα is an important regulator of hepatic lipogenesis and ChREBPα activity upon glucose, but not fructose feeding in mice.
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34
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Imbalanced Insulin Actions in Obesity and Type 2 Diabetes: Key Mouse Models of Insulin Signaling Pathway. Cell Metab 2017; 25:797-810. [PMID: 28380373 DOI: 10.1016/j.cmet.2017.03.004] [Citation(s) in RCA: 106] [Impact Index Per Article: 15.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/26/2016] [Revised: 01/06/2017] [Accepted: 03/08/2017] [Indexed: 02/06/2023]
Abstract
Since the discovery of the tyrosine kinase activity of the insulin receptor (IR), researchers have been engaged in intensive efforts to resolve physiological functions of IR and its major downstream targets, insulin receptor substrate 1 (Irs1) and Irs2. Studies conducted using systemic and tissue-specific gene-knockout mice of IR, Irs1, and Irs2 have revealed the physiological roles of these molecules in each tissue and interactions among multiple tissues. In obesity and type 2 diabetes, selective downregulation of Irs2 and its downstream actions to cause reduced insulin actions was associated with increased insulin actions through Irs1 in variety tissues. Thus, we propose the novel concept of "organ- and pathway-specific imbalanced insulin action" in obesity and type 2 diabetes, which includes and extends "selective insulin resistance." This Review focuses on recent progress in understanding insulin signaling and insulin resistance using key mouse models for elucidating pathophysiology of human obesity and type 2 diabetes.
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35
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Baldini SF, Wavelet C, Hainault I, Guinez C, Lefebvre T. The Nutrient-Dependent O -GlcNAc Modification Controls the Expression of Liver Fatty Acid Synthase. J Mol Biol 2016; 428:3295-3304. [DOI: 10.1016/j.jmb.2016.04.035] [Citation(s) in RCA: 37] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2016] [Revised: 04/27/2016] [Accepted: 04/29/2016] [Indexed: 12/13/2022]
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36
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Wang Y, Viscarra J, Kim SJ, Sul HS. Transcriptional regulation of hepatic lipogenesis. Nat Rev Mol Cell Biol 2016; 16:678-89. [PMID: 26490400 DOI: 10.1038/nrm4074] [Citation(s) in RCA: 453] [Impact Index Per Article: 56.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Fatty acid and fat synthesis in the liver is a highly regulated metabolic pathway that is important for very low-density lipoprotein (VLDL) production and thus energy distribution to other tissues. Having common features at their promoter regions, lipogenic genes are coordinately regulated at the transcriptional level. Transcription factors, such as upstream stimulatory factors (USFs), sterol regulatory element-binding protein 1C (SREBP1C), liver X receptors (LXRs) and carbohydrate-responsive element-binding protein (ChREBP) have crucial roles in this process. Recently, insights have been gained into the signalling pathways that regulate these transcription factors. After feeding, high blood glucose and insulin levels activate lipogenic genes through several pathways, including the DNA-dependent protein kinase (DNA-PK), atypical protein kinase C (aPKC) and AKT-mTOR pathways. These pathways control the post-translational modifications of transcription factors and co-regulators, such as phosphorylation, acetylation or ubiquitylation, that affect their function, stability and/or localization. Dysregulation of lipogenesis can contribute to hepatosteatosis, which is associated with obesity and insulin resistance.
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Affiliation(s)
- Yuhui Wang
- Department of Nutritional Sciences and Toxicology, University of California, Berkeley, California 94720, USA
| | - Jose Viscarra
- Department of Nutritional Sciences and Toxicology, University of California, Berkeley, California 94720, USA
| | - Sun-Joong Kim
- Department of Nutritional Sciences and Toxicology, University of California, Berkeley, California 94720, USA
| | - Hei Sook Sul
- Department of Nutritional Sciences and Toxicology, University of California, Berkeley, California 94720, USA
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Ballestri S, Nascimbeni F, Romagnoli D, Baldelli E, Targher G, Lonardo A. Type 2 Diabetes in Non-Alcoholic Fatty Liver Disease and Hepatitis C Virus Infection--Liver: The "Musketeer" in the Spotlight. Int J Mol Sci 2016; 17:355. [PMID: 27005620 PMCID: PMC4813216 DOI: 10.3390/ijms17030355] [Citation(s) in RCA: 35] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2016] [Revised: 02/29/2016] [Accepted: 03/02/2016] [Indexed: 02/07/2023] Open
Abstract
The pathogenesis of type 2 diabetes (T2D) involves chronic hyperinsulinemia due to systemic and hepatic insulin resistance (IR), which if uncorrected, will lead to progressive pancreatic beta cell failure in predisposed individuals. Non-alcoholic fatty liver disease (NAFLD) encompasses a spectrum of fatty (simple steatosis and steatohepatitis) and non-fatty liver changes (NASH-cirrhosis with or without hepatocellular carcinoma (HCC)) that are commonly observed among individuals with multiple metabolic derangements, notably including visceral obesity, IR and T2D. Hepatitis C virus (HCV) infection is also often associated with both hepatic steatosis and features of a specific HCV-associated dysmetabolic syndrome. In recent years, the key role of the steatotic liver in the development of IR and T2D has been increasingly recognized. Thus, in this comprehensive review we summarize the rapidly expanding body of evidence that links T2D with NAFLD and HCV infection. For each of these two liver diseases with systemic manifestations, we discuss the epidemiological burden, the pathophysiologic mechanisms and the clinical implications. To date, substantial evidence suggests that NAFLD and HCV play a key role in T2D development and that the interaction of T2D with liver disease may result in a "vicious circle", eventually leading to an increased risk of all-cause mortality and liver-related and cardiovascular complications. Preliminary evidence also suggests that improvement of NAFLD is associated with a decreased incidence of T2D. Similarly, the prevention of T2D following HCV eradication in the era of direct-acting antiviral agents is a biologically plausible result. However, additional studies are required for further clarification of mechanisms involved.
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Affiliation(s)
- Stefano Ballestri
- Operating Unit Internal Medicine, Pavullo General Hospital, Azienda USL Modena, ViaSuore di San Giuseppe Benedetto Cottolengo, 5, Pavullo, 41026 Modena, Italy.
| | - Fabio Nascimbeni
- Outpatient Liver Clinic and Operating Unit Internal Medicine, NOCSAE, Azienda USL Modena, Via P. Giardini, 1355, 41126 Modena, Italy.
- Department of Biomedical, Metabolic and Neural Sciences, University of Modena and Reggio Emilia, Via P. Giardini, 1355, 41126 Modena, Italy.
| | - Dante Romagnoli
- Outpatient Liver Clinic and Operating Unit Internal Medicine, NOCSAE, Azienda USL Modena, Via P. Giardini, 1355, 41126 Modena, Italy.
| | - Enrica Baldelli
- Department of Biomedical, Metabolic and Neural Sciences, University of Modena and Reggio Emilia, Via P. Giardini, 1355, 41126 Modena, Italy.
| | - Giovanni Targher
- Section of Endocrinology, Diabetes and Metabolism, Department of Medicine, University and Azienda Ospedaliera Universitaria Integrata of Verona, Piazzale Stefani, 1, 37126 Verona, Italy.
| | - Amedeo Lonardo
- Outpatient Liver Clinic and Operating Unit Internal Medicine, NOCSAE, Azienda USL Modena, Via P. Giardini, 1355, 41126 Modena, Italy.
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TCDD-inducible poly-ADP-ribose polymerase (TIPARP/PARP7) mono-ADP-ribosylates and co-activates liver X receptors. Biochem J 2016; 473:899-910. [PMID: 26814197 DOI: 10.1042/bj20151077] [Citation(s) in RCA: 36] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2015] [Accepted: 01/26/2016] [Indexed: 12/27/2022]
Abstract
Members of the poly-ADP-ribose polymerase (PARP) family catalyse the ADP-ribosylation of target proteins and are known to play important roles in many cellular processes, including DNA repair, differentiation and transcription. The majority of PARPs exhibit mono-ADP-ribosyltransferase activity rather than PARP activity; however, little is known about their biological activity. In the present study, we report that 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD)-inducible poly-ADP-ribose polymerase (TIPARP), mono-ADP-ribosylates and positively regulates liver X receptor α (LXRα) and LXRβ activity. Overexpression of TIPARP enhanced LXR-reporter gene activity. TIPARP knockdown or deletion reduced LXR regulated target gene expression levels in HepG2 cells and in Tiparp(-/-)mouse embryonic fibroblasts (MEFs) respectively. Deletion and mutagenesis studies showed that TIPARP's zinc-finger and catalytic domains were required to enhance LXR activity. Protein interaction studies using TIPARP and LXRα/β peptide arrays revealed that LXRs interacted with an N-terminal sequence (a.a. 209-236) of TIPARP, which also overlapped with a putative co-activator domain of TIPARP (a.a. 200-225). Immunofluorescence studies showed that TIPARP and LXRα or LXRβ co-localized in the nucleus.In vitroribosylation assays provided evidence that TIPARP mono-ADP-ribosylated both LXRα and LXRβ. Co-immunoprecipitation (co-IP) studies revealed that ADP-ribosylase macrodomain 1 (MACROD1), but not MACROD2, interacted with LXRs in a TIPARP-dependent manner. This was complemented by reporter gene studies showing that MACROD1, but not MACROD2, prevented the TIPARP-dependent increase in LXR activity. GW3965-dependent increases in hepatic Srebp1 mRNA and protein expression levels were reduced in Tiparp(-/-)mice compared with Tiparp(+/+)mice. Taken together, these data identify a new mechanism of LXR regulation that involves TIPARP, ADP-ribosylation and MACROD1.
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Baldini SF, Lefebvre T. O-GlcNAcylation and the Metabolic Shift in High-Proliferating Cells: All the Evidence Suggests that Sugars Dictate the Flux of Lipid Biogenesis in Tumor Processes. Front Oncol 2016; 6:6. [PMID: 26835421 PMCID: PMC4722119 DOI: 10.3389/fonc.2016.00006] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2015] [Accepted: 01/08/2016] [Indexed: 12/25/2022] Open
Abstract
Cancer cells are characterized by their high capability to proliferate. This imposes an accelerated biosynthesis of membrane compounds to respond to the need for increasing the membrane surface of dividing cells and remodeling the structure of lipid microdomains. Recently, attention has been paid to the upregulation of O-GlcNAcylation processes observed in cancer cells. Although O-GlcNAcylation of lipogenic transcriptional regulators is described in the literature (e.g., FXR, LXR, ChREBP), little is known about the regulation of the enzymes that drive lipogenesis: acetyl co-enzyme A carboxylase and fatty acid synthase (FAS). The expression and catalytic activity of both FAS and O-GlcNAc transferase (OGT) are high in cancer cells but the reciprocal regulation of the two enzymes remains unexplored. In this perspective, we collected data linking FAS and OGT and, in so doing, pave the way for the exploration of the intricate functions of these two actors that play a central role in tumor growth.
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Affiliation(s)
- Steffi F Baldini
- University Lille, CNRS, UMR 8576, UGSF, Unité de Glycobiologie Structurale et Fonctionnelle , Lille , France
| | - Tony Lefebvre
- University Lille, CNRS, UMR 8576, UGSF, Unité de Glycobiologie Structurale et Fonctionnelle , Lille , France
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Samuel VT, Shulman GI. The pathogenesis of insulin resistance: integrating signaling pathways and substrate flux. J Clin Invest 2016; 126:12-22. [PMID: 26727229 DOI: 10.1172/jci77812] [Citation(s) in RCA: 808] [Impact Index Per Article: 101.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
Insulin resistance arises when the nutrient storage pathways evolved to maximize efficient energy utilization are exposed to chronic energy surplus. Ectopic lipid accumulation in liver and skeletal muscle triggers pathways that impair insulin signaling, leading to reduced muscle glucose uptake and decreased hepatic glycogen synthesis. Muscle insulin resistance, due to ectopic lipid, precedes liver insulin resistance and diverts ingested glucose to the liver, resulting in increased hepatic de novo lipogenesis and hyperlipidemia. Subsequent macrophage infiltration into white adipose tissue (WAT) leads to increased lipolysis, which further increases hepatic triglyceride synthesis and hyperlipidemia due to increased fatty acid esterification. Macrophage-induced WAT lipolysis also stimulates hepatic gluconeogenesis, promoting fasting and postprandial hyperglycemia through increased fatty acid delivery to the liver, which results in increased hepatic acetyl-CoA content, a potent activator of pyruvate carboxylase, and increased glycerol conversion to glucose. These substrate-regulated processes are mostly independent of insulin signaling in the liver but are dependent on insulin signaling in WAT, which becomes defective with inflammation. Therapies that decrease ectopic lipid storage and diminish macrophage-induced WAT lipolysis will reverse the root causes of type 2 diabetes.
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