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Sartori MR, Navarro CDC, Castilho RF, Vercesi AE. Aggravation of hepatic lipidosis in red-footed tortoise Chelonoidis carbonaria with age is associated with alterations in liver mitochondria. Comp Biochem Physiol B Biochem Mol Biol 2022; 260:110731. [PMID: 35276383 DOI: 10.1016/j.cbpb.2022.110731] [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: 12/14/2021] [Revised: 02/14/2022] [Accepted: 03/04/2022] [Indexed: 11/26/2022]
Abstract
The occurrence of hepatic lipidosis is commonly reported in different reptilian species, especially in animals under captivity. Liver accumulation of fat is associated with disorders, better described in mammals as non-alcoholic fatty liver diseases (NAFLD), ranging from simple steatosis, to non-alcoholic steatohepatitis (NASH), and to more severe lesions of cirrhosis and hepatocellular carcinoma. Mitochondria play a central role in NAFLD pathogenesis, therefore in this study we characterized livers of ad libitum fed captive red-footed tortoise Chelonoidis carbonaria through histological and mitochondrial function evaluations of juvenile and adult individuals. Livers from adult tortoises exhibited higher levels of lipids, melanomacrophages centers and melanin than juveniles. The observed high score levels of histopathological alterations in adult tortoises, such as microvesicular steatosis, inflammation and fibrosis, indicated the progression to a NASH condition. Mitochondrial oxygen consumption at different respiratory states and with different substrates was 30 to 58% lower in adult when compared to juvenile tortoises. Despite citrate synthase activity was also lower in adults, cardiolipin content was similar to juveniles, indicating that mitochondrial mass was unaffected by age. Mitochondrial Ca2+ retention capacity was reduced by 70% in adult tortoises. Overall, we found that aggravation of NAFLD in ad libitum fed captive tortoises is associated with compromised mitochondrial function, indicating a critical role of the organelle in liver disease progression in reptiles.
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Affiliation(s)
- Marina R Sartori
- Department of Pathology, Faculty of Medical Sciences, University of Campinas (UNICAMP), Campinas, SP 13083-887, Brazil.
| | - Claudia D C Navarro
- Department of Pathology, Faculty of Medical Sciences, University of Campinas (UNICAMP), Campinas, SP 13083-887, Brazil
| | - Roger F Castilho
- Department of Pathology, Faculty of Medical Sciences, University of Campinas (UNICAMP), Campinas, SP 13083-887, Brazil
| | - Anibal E Vercesi
- Department of Pathology, Faculty of Medical Sciences, University of Campinas (UNICAMP), Campinas, SP 13083-887, Brazil
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2
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Gao W, Zhao H, Wei X, Meng X, Wu K, Liu Y. A Green and Economical Method for Preparing Potassium Glutamate through Electrodialysis Metathesis. Ind Eng Chem Res 2022. [DOI: 10.1021/acs.iecr.1c04556] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Wenjie Gao
- Collaborative Innovation Center for Environmental Pollution Control and Ecological Restoration of Anhui Province, School of Biology, Food and Environment, Hefei University, Hefei 230601, PR China
| | - Huan Zhao
- Collaborative Innovation Center for Environmental Pollution Control and Ecological Restoration of Anhui Province, School of Biology, Food and Environment, Hefei University, Hefei 230601, PR China
| | - Xinlai Wei
- Collaborative Innovation Center for Environmental Pollution Control and Ecological Restoration of Anhui Province, School of Biology, Food and Environment, Hefei University, Hefei 230601, PR China
- Department of Applied Chemistry, Anhui Provincial Engineering Laboratory of Functional Membrane Science and Technology, School of Chemistry and Materials Science, University of Science and Technology of China, Hefei, Anhui 230026, PR China
| | - Xiangwu Meng
- Collaborative Innovation Center for Environmental Pollution Control and Ecological Restoration of Anhui Province, School of Biology, Food and Environment, Hefei University, Hefei 230601, PR China
| | - Ke Wu
- Collaborative Innovation Center for Environmental Pollution Control and Ecological Restoration of Anhui Province, School of Biology, Food and Environment, Hefei University, Hefei 230601, PR China
- Anhui Key Laboratory of Sewage Purification and Eco-restoration Materials, Hefei 230088, PR China
| | - Yun Liu
- Collaborative Innovation Center for Environmental Pollution Control and Ecological Restoration of Anhui Province, School of Biology, Food and Environment, Hefei University, Hefei 230601, PR China
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3
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Moldovan OL, Rusu A, Tanase C, Vari CE. Glutamate - A multifaceted molecule: Endogenous neurotransmitter, controversial food additive, design compound for anti-cancer drugs. A critical appraisal. Food Chem Toxicol 2021; 153:112290. [PMID: 34023459 DOI: 10.1016/j.fct.2021.112290] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2021] [Revised: 05/10/2021] [Accepted: 05/14/2021] [Indexed: 12/18/2022]
Abstract
One of the most widely used flavour enhancers in the food industry is monosodium glutamate (MSG). MSG consumption has been on an upward trend, worrying in terms of potential toxic effects. This review is focused on the long-term toxicity of MSG and the experimental evidence that supports it. The article's primary purpose was to survey recently published data regarding the consumption of MSG within safe limits. The administered doses in animal models are very varied and have given rise to controversy. Also, the paper comprises pathways to lower MSG toxicity and highlight other underexploited biological effects, as anti-cancer potential. The administration of MSG, combined with various compounds, has been shown benefit against toxic effects. Several recent studies have identified a possible mechanism that recommends MSG and some derivatives as potential anti-cancer agents. New anti-cancer compounds based on the glutamic acid structure must be studied and further exploited. International regulations require harmonization of safe doses of MSG based on current scientific studies. Replacing MSG with other umami flavour enhancers may be a safer alternative for human health in the future. The biological consequences of MSG consumption or therapeutical administration have not been fully deciphered yet.
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Affiliation(s)
- Octavia-Laura Moldovan
- Medicine and Pharmacy Doctoral School, George Emil Palade University of Medicine, Pharmacy, Science and Technology of Târgu Mureș, 540142, Târgu Mureș, Romania.
| | - Aura Rusu
- Pharmaceutical and Therapeutic Chemistry Department, Faculty of Pharmacy, George Emil Palade University of Medicine, Pharmacy, Science and Technology of Târgu Mureș, 540142, Târgu Mureș, Romania.
| | - Corneliu Tanase
- Pharmaceutical Botany Department, Faculty of Pharmacy, George Emil Palade University of Medicine, Pharmacy, Science and Technology of Târgu Mureș, 540142, Târgu Mureș, Romania.
| | - Camil-Eugen Vari
- Pharmacy and Clinical Pharmacy Department, Faculty of Pharmacy, George Emil Palade University of Medicine, Pharmacy, Science and Technology of Târgu Mureș, 540142, Târgu Mureș, Romania.
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4
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Nassir F. Role of acetylation in nonalcoholic fatty liver disease: a focus on SIRT1 and SIRT3. EXPLORATION OF MEDICINE 2020. [DOI: 10.37349/emed.2020.00017] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022] Open
Abstract
Nonalcoholic fatty liver disease (NAFLD) has become the most prevalent liver chronic disease worldwide. The pathogenesis of NAFLD is complex and involves many metabolic enzymes and multiple pathways. Posttranslational modifications of proteins (PMPs) added another layer of complexity to the pathogenesis of NAFLD. PMPs change protein properties and regulate many biological functions, including cellular localization, stability, intracellular signaling, and protein function. Lysine acetylation is a common reversible PMP that consists of the transfer of an acetyl group from acetyl-coenzyme A (CoA) to a lysine residue on targeted proteins. The deacetylation reaction is catalyzed by deacetylases called sirtuins. This review summarizes the role of acetylation in NAFLD with a focus on sirtuins 1 and 3.
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Affiliation(s)
- Fatiha Nassir
- Department of Medicine, Division of Gastroenterology and Hepatology, University of Missouri, Columbia, MO 65212, USA
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5
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Bonora M, Patergnani S, Ramaccini D, Morciano G, Pedriali G, Kahsay AE, Bouhamida E, Giorgi C, Wieckowski MR, Pinton P. Physiopathology of the Permeability Transition Pore: Molecular Mechanisms in Human Pathology. Biomolecules 2020; 10:biom10070998. [PMID: 32635556 PMCID: PMC7408088 DOI: 10.3390/biom10070998] [Citation(s) in RCA: 79] [Impact Index Per Article: 19.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2020] [Revised: 06/29/2020] [Accepted: 07/02/2020] [Indexed: 12/13/2022] Open
Abstract
Mitochondrial permeability transition (MPT) is the sudden loss in the permeability of the inner mitochondrial membrane (IMM) to low-molecular-weight solutes. Due to osmotic forces, MPT is paralleled by a massive influx of water into the mitochondrial matrix, eventually leading to the structural collapse of the organelle. Thus, MPT can initiate outer-mitochondrial-membrane permeabilization (MOMP), promoting the activation of the apoptotic caspase cascade and caspase-independent cell-death mechanisms. The induction of MPT is mostly dependent on mitochondrial reactive oxygen species (ROS) and Ca2+, but is also dependent on the metabolic stage of the affected cell and signaling events. Therefore, since its discovery in the late 1970s, the role of MPT in human pathology has been heavily investigated. Here, we summarize the most significant findings corroborating a role for MPT in the etiology of a spectrum of human diseases, including diseases characterized by acute or chronic loss of adult cells and those characterized by neoplastic initiation.
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Affiliation(s)
- Massimo Bonora
- Department of Medical Sciences, Laboratory for Technologies of Advanced Therapies (LTTA), University of Ferrara, 44121 Ferrara, Italy; (S.P.); (D.R.); (G.M.); (G.P.); (A.E.K.); (E.B.); (C.G.)
- Correspondence: (M.B.); (P.P.)
| | - Simone Patergnani
- Department of Medical Sciences, Laboratory for Technologies of Advanced Therapies (LTTA), University of Ferrara, 44121 Ferrara, Italy; (S.P.); (D.R.); (G.M.); (G.P.); (A.E.K.); (E.B.); (C.G.)
| | - Daniela Ramaccini
- Department of Medical Sciences, Laboratory for Technologies of Advanced Therapies (LTTA), University of Ferrara, 44121 Ferrara, Italy; (S.P.); (D.R.); (G.M.); (G.P.); (A.E.K.); (E.B.); (C.G.)
| | - Giampaolo Morciano
- Department of Medical Sciences, Laboratory for Technologies of Advanced Therapies (LTTA), University of Ferrara, 44121 Ferrara, Italy; (S.P.); (D.R.); (G.M.); (G.P.); (A.E.K.); (E.B.); (C.G.)
- Maria Cecilia Hospital, GVM Care & Research, Via Corriera 1, Cotignola, 48033 Ravenna, Italy
| | - Gaia Pedriali
- Department of Medical Sciences, Laboratory for Technologies of Advanced Therapies (LTTA), University of Ferrara, 44121 Ferrara, Italy; (S.P.); (D.R.); (G.M.); (G.P.); (A.E.K.); (E.B.); (C.G.)
- Maria Cecilia Hospital, GVM Care & Research, Via Corriera 1, Cotignola, 48033 Ravenna, Italy
| | - Asrat Endrias Kahsay
- Department of Medical Sciences, Laboratory for Technologies of Advanced Therapies (LTTA), University of Ferrara, 44121 Ferrara, Italy; (S.P.); (D.R.); (G.M.); (G.P.); (A.E.K.); (E.B.); (C.G.)
| | - Esmaa Bouhamida
- Department of Medical Sciences, Laboratory for Technologies of Advanced Therapies (LTTA), University of Ferrara, 44121 Ferrara, Italy; (S.P.); (D.R.); (G.M.); (G.P.); (A.E.K.); (E.B.); (C.G.)
| | - Carlotta Giorgi
- Department of Medical Sciences, Laboratory for Technologies of Advanced Therapies (LTTA), University of Ferrara, 44121 Ferrara, Italy; (S.P.); (D.R.); (G.M.); (G.P.); (A.E.K.); (E.B.); (C.G.)
| | - Mariusz R. Wieckowski
- Laboratory of Mitochondrial Biology and Metabolism, Nencki Institute of Experimental Biology of the Polish Academy of Sciences, 3 Pasteur Str., 02-093 Warsaw, Poland;
| | - Paolo Pinton
- Department of Medical Sciences, Laboratory for Technologies of Advanced Therapies (LTTA), University of Ferrara, 44121 Ferrara, Italy; (S.P.); (D.R.); (G.M.); (G.P.); (A.E.K.); (E.B.); (C.G.)
- Maria Cecilia Hospital, GVM Care & Research, Via Corriera 1, Cotignola, 48033 Ravenna, Italy
- Correspondence: (M.B.); (P.P.)
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6
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Chen Z, Tian R, She Z, Cai J, Li H. Role of oxidative stress in the pathogenesis of nonalcoholic fatty liver disease. Free Radic Biol Med 2020; 152:116-141. [PMID: 32156524 DOI: 10.1016/j.freeradbiomed.2020.02.025] [Citation(s) in RCA: 589] [Impact Index Per Article: 147.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/11/2019] [Revised: 02/20/2020] [Accepted: 02/26/2020] [Indexed: 02/07/2023]
Abstract
Nonalcoholic fatty liver disease (NAFLD) has emerged as the most common chronic liver disease worldwide and is strongly associated with the presence of oxidative stress. Disturbances in lipid metabolism lead to hepatic lipid accumulation, which affects different reactive oxygen species (ROS) generators, including mitochondria, endoplasmic reticulum, and NADPH oxidase. Mitochondrial function adapts to NAFLD mainly through the downregulation of the electron transport chain (ETC) and the preserved or enhanced capacity of mitochondrial fatty acid oxidation, which stimulates ROS overproduction within different ETC components upstream of cytochrome c oxidase. However, non-ETC sources of ROS, in particular, fatty acid β-oxidation, appear to produce more ROS in hepatic metabolic diseases. Endoplasmic reticulum stress and NADPH oxidase alterations are also associated with NAFLD, but the degree of their contribution to oxidative stress in NAFLD remains unclear. Increased ROS generation induces changes in insulin sensitivity and in the expression and activity of key enzymes involved in lipid metabolism. Moreover, the interaction between redox signaling and innate immune signaling forms a complex network that regulates inflammatory responses. Based on the mechanistic view described above, this review summarizes the mechanisms that may account for the excessive production of ROS, the potential mechanistic roles of ROS that drive NAFLD progression, and therapeutic interventions that are related to oxidative stress.
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Affiliation(s)
- Ze Chen
- Department of Cardiology, Renmin Hospital of Wuhan University, Wuhan, 430060, PR China; Institute of Model Animals of Wuhan University, Wuhan, 430072, PR China
| | - Ruifeng Tian
- Department of Cardiology, Renmin Hospital of Wuhan University, Wuhan, 430060, PR China; Institute of Model Animals of Wuhan University, Wuhan, 430072, PR China
| | - Zhigang She
- Department of Cardiology, Renmin Hospital of Wuhan University, Wuhan, 430060, PR China; Institute of Model Animals of Wuhan University, Wuhan, 430072, PR China; Basic Medical School, Wuhan University, Wuhan, 430071, PR China; Medical Research Institute, School of Medicine, Wuhan University, Wuhan, 430071, PR China
| | - Jingjing Cai
- Department of Cardiology, Renmin Hospital of Wuhan University, Wuhan, 430060, PR China; Department of Cardiology, The Third Xiangya Hospital, Central South University, Changsha, 410013, PR China; Institute of Model Animals of Wuhan University, Wuhan, 430072, PR China
| | - Hongliang Li
- Department of Cardiology, Renmin Hospital of Wuhan University, Wuhan, 430060, PR China; Institute of Model Animals of Wuhan University, Wuhan, 430072, PR China; Basic Medical School, Wuhan University, Wuhan, 430071, PR China; Medical Research Institute, School of Medicine, Wuhan University, Wuhan, 430071, PR China.
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7
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Morais Mewes J, Rodrigues Silva Gasparin F, Yoshida T, Amâncio Daniel da Silva M, Raquel Marçal Natali M, Francisco Veiga Bizerra P, Sayuri Utsunomiya K, Hideo Gilglioni E, Shigueaki Mito M, Cristiane Mantovanelli G, Thais Lima de Souza B, Makiyama Klosowski E, Luiza Ishii-Iwamoto E, Constantin J, Polimeni Constantin R. The Role of Mitochondria in Sex-Dependent Differences in Hepatic Steatosis and Oxidative Stress in Response to Cafeteria Diet-Induced Obesity in Mice. Nutrients 2019; 11:E1618. [PMID: 31315289 PMCID: PMC6682896 DOI: 10.3390/nu11071618] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2019] [Revised: 06/03/2019] [Accepted: 07/11/2019] [Indexed: 12/30/2022] Open
Abstract
Female mice fed a cafeteria diet (FCaf) develop higher liver steatosis and oxidative stress than males (MCaf) as a consequence of unresolved ER stress. Here, we investigated whether mitochondria play a role in this sex difference. The isolated mitochondria from FCaf showed more signs of oxidative stress than those of MCaf, correlated with a reduced content of GSH, increased amount of reactive oxygen species (ROS), and lower activities of enzymes involved in ROS neutralisation. Mitochondria from FCaf and MCaf livers exhibited lower rates of succinate-driven state III respiration and reduced ATPase activity in intact coupled mitochondria compared to their controls fed a standard diet (FC and MC), with no differences between the sexes. Fatty acid oxidation in mitochondria and peroxisomes was higher in MCaf and FCaf compared to their respective controls. In the intact perfused liver, there was no difference between sex or diet regarding the fatty acid oxidation rate. These results indicated that cafeteria diet did not affect mitochondrial energy metabolism, even in FCaf livers, which have higher steatosis and cellular oxidative stress. Nevertheless, the increase in mitochondrial ROS generation associated with a decrease in the antioxidant defence capacity, probably contributes to inducing or reinforcing the ER stress in FCaf livers.
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Affiliation(s)
- Juliana Morais Mewes
- Department of Biochemistry, Laboratory of Biological Oxidations and Laboratory of Experimental Steatosis, State University of Maringá, Maringá 87020-900, Paraná, Brazil
| | - Fabiana Rodrigues Silva Gasparin
- Department of Biochemistry, Laboratory of Biological Oxidations and Laboratory of Experimental Steatosis, State University of Maringá, Maringá 87020-900, Paraná, Brazil
| | - Tiago Yoshida
- Department of Biochemistry, Laboratory of Biological Oxidations and Laboratory of Experimental Steatosis, State University of Maringá, Maringá 87020-900, Paraná, Brazil
| | - Mariana Amâncio Daniel da Silva
- Department of Biochemistry, Laboratory of Biological Oxidations and Laboratory of Experimental Steatosis, State University of Maringá, Maringá 87020-900, Paraná, Brazil
| | - Maria Raquel Marçal Natali
- Department of Morphophysiological Sciences, State University of Maringá, Maringá 87020-900, Paraná, Brazil
| | - Paulo Francisco Veiga Bizerra
- Department of Biochemistry, Laboratory of Biological Oxidations and Laboratory of Experimental Steatosis, State University of Maringá, Maringá 87020-900, Paraná, Brazil
| | - Karina Sayuri Utsunomiya
- Department of Biochemistry, Laboratory of Biological Oxidations and Laboratory of Experimental Steatosis, State University of Maringá, Maringá 87020-900, Paraná, Brazil
| | - Eduardo Hideo Gilglioni
- Department of Biochemistry, Laboratory of Biological Oxidations and Laboratory of Experimental Steatosis, State University of Maringá, Maringá 87020-900, Paraná, Brazil
| | - Marcio Shigueaki Mito
- Department of Biochemistry, Laboratory of Biological Oxidations and Laboratory of Experimental Steatosis, State University of Maringá, Maringá 87020-900, Paraná, Brazil
| | - Gislaine Cristiane Mantovanelli
- Department of Biochemistry, Laboratory of Biological Oxidations and Laboratory of Experimental Steatosis, State University of Maringá, Maringá 87020-900, Paraná, Brazil
| | - Byanca Thais Lima de Souza
- Department of Biochemistry, Laboratory of Biological Oxidations and Laboratory of Experimental Steatosis, State University of Maringá, Maringá 87020-900, Paraná, Brazil
| | - Eduardo Makiyama Klosowski
- Department of Biochemistry, Laboratory of Biological Oxidations and Laboratory of Experimental Steatosis, State University of Maringá, Maringá 87020-900, Paraná, Brazil
| | - Emy Luiza Ishii-Iwamoto
- Department of Biochemistry, Laboratory of Biological Oxidations and Laboratory of Experimental Steatosis, State University of Maringá, Maringá 87020-900, Paraná, Brazil
| | - Jorgete Constantin
- Department of Biochemistry, Laboratory of Biological Oxidations and Laboratory of Experimental Steatosis, State University of Maringá, Maringá 87020-900, Paraná, Brazil
| | - Rodrigo Polimeni Constantin
- Department of Biochemistry, Laboratory of Biological Oxidations and Laboratory of Experimental Steatosis, State University of Maringá, Maringá 87020-900, Paraná, Brazil.
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8
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Yao L, Cao B, Cheng Q, Cai W, Ye C, Liang J, Liu W, Tan L, Yan M, Li B, He J, Hwang SH, Zhang X, Wang C, Ai D, Hammock BD, Zhu Y. Inhibition of soluble epoxide hydrolase ameliorates hyperhomocysteinemia-induced hepatic steatosis by enhancing β-oxidation of fatty acid in mice. Am J Physiol Gastrointest Liver Physiol 2019; 316:G527-G538. [PMID: 30789748 PMCID: PMC6483021 DOI: 10.1152/ajpgi.00148.2018] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
Hepatic steatosis is the beginning phase of nonalcoholic fatty liver disease, and hyperhomocysteinemia (HHcy) is a significant risk factor. Soluble epoxide hydrolase (sEH) hydrolyzes epoxyeicosatrienoic acids (EETs) and other epoxy fatty acids, attenuating their cardiovascular protective effects. However, the involvement of sEH in HHcy-induced hepatic steatosis is unknown. The current study aimed to explore the role of sEH in HHcy-induced lipid disorder. We fed 6-wk-old male mice a chow diet or 2% (wt/wt) high-metnionine diet for 8 wk to establish the HHcy model. A high level of homocysteine induced lipid accumulation in vivo and in vitro, which was concomitant with the increased activity and expression of sEH. Treatment with a highly selective specific sEH inhibitor (0.8 mg·kg-1·day-1 for the animal model and 1 μM for cells) prevented HHcy-induced lipid accumulation in vivo and in vitro. Inhibition of sEH activated the peroxisome proliferator-activated receptor-α (PPAR-α), as evidenced by elevated β-oxidation of fatty acids and the expression of PPAR-α target genes in HHcy-induced hepatic steatosis. In primary cultured hepatocytes, the effect of sEH inhibition on PPAR-α activation was further confirmed by a marked increase in PPAR-response element luciferase activity, which was reversed by knock down of PPAR-α. Of note, 11,12-EET ligand dependently activated PPAR-α. Thus increased sEH activity is a key determinant in the pathogenesis of HHcy-induced hepatic steatosis, and sEH inhibition could be an effective treatment for HHcy-induced hepatic steatosis. NEW & NOTEWORTHY In the current study, we demonstrated that upregulation of soluble epoxide hydrolase (sEH) is involved in the hyperhomocysteinemia (HHcy)-caused hepatic steatosis in an HHcy mouse model and in murine primary hepatocytes. Improving hepatic steatosis in HHcy mice by pharmacological inhibition of sEH to activate peroxisome proliferator-activated receptor-α was ligand dependent, and sEH could be a potential therapeutic target for the treatment of nonalcoholic fatty liver disease.
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Affiliation(s)
- Liu Yao
- 1Tianjin Key Laboratory of Metabolic Diseases; Key Laboratory of Immune Microenvironment and Disease (Ministry of Education); Collaborative Innovation Center of Tianjin for Medical Epigenetics and Department of Physiology and Pathophysiology, Tianjin Medical University, Tianjin, China
| | - Boyang Cao
- 1Tianjin Key Laboratory of Metabolic Diseases; Key Laboratory of Immune Microenvironment and Disease (Ministry of Education); Collaborative Innovation Center of Tianjin for Medical Epigenetics and Department of Physiology and Pathophysiology, Tianjin Medical University, Tianjin, China
| | - Qian Cheng
- 1Tianjin Key Laboratory of Metabolic Diseases; Key Laboratory of Immune Microenvironment and Disease (Ministry of Education); Collaborative Innovation Center of Tianjin for Medical Epigenetics and Department of Physiology and Pathophysiology, Tianjin Medical University, Tianjin, China
| | - Wenbin Cai
- 1Tianjin Key Laboratory of Metabolic Diseases; Key Laboratory of Immune Microenvironment and Disease (Ministry of Education); Collaborative Innovation Center of Tianjin for Medical Epigenetics and Department of Physiology and Pathophysiology, Tianjin Medical University, Tianjin, China
| | - Chenji Ye
- 1Tianjin Key Laboratory of Metabolic Diseases; Key Laboratory of Immune Microenvironment and Disease (Ministry of Education); Collaborative Innovation Center of Tianjin for Medical Epigenetics and Department of Physiology and Pathophysiology, Tianjin Medical University, Tianjin, China
| | - Jing Liang
- 1Tianjin Key Laboratory of Metabolic Diseases; Key Laboratory of Immune Microenvironment and Disease (Ministry of Education); Collaborative Innovation Center of Tianjin for Medical Epigenetics and Department of Physiology and Pathophysiology, Tianjin Medical University, Tianjin, China
| | - Wenli Liu
- 1Tianjin Key Laboratory of Metabolic Diseases; Key Laboratory of Immune Microenvironment and Disease (Ministry of Education); Collaborative Innovation Center of Tianjin for Medical Epigenetics and Department of Physiology and Pathophysiology, Tianjin Medical University, Tianjin, China
| | - Lu Tan
- 2Department of Laboratory Animal Science and Technology, Tianjin Medical University, Tianjin, China
| | - Meng Yan
- 1Tianjin Key Laboratory of Metabolic Diseases; Key Laboratory of Immune Microenvironment and Disease (Ministry of Education); Collaborative Innovation Center of Tianjin for Medical Epigenetics and Department of Physiology and Pathophysiology, Tianjin Medical University, Tianjin, China
| | - Bochuan Li
- 1Tianjin Key Laboratory of Metabolic Diseases; Key Laboratory of Immune Microenvironment and Disease (Ministry of Education); Collaborative Innovation Center of Tianjin for Medical Epigenetics and Department of Physiology and Pathophysiology, Tianjin Medical University, Tianjin, China
| | - Jinlong He
- 1Tianjin Key Laboratory of Metabolic Diseases; Key Laboratory of Immune Microenvironment and Disease (Ministry of Education); Collaborative Innovation Center of Tianjin for Medical Epigenetics and Department of Physiology and Pathophysiology, Tianjin Medical University, Tianjin, China
| | - Sung Hee Hwang
- 3Department of Entomology and Nematology and University of California, Davis Comprehensive Cancer Center, Davis, California
| | - Xu Zhang
- 1Tianjin Key Laboratory of Metabolic Diseases; Key Laboratory of Immune Microenvironment and Disease (Ministry of Education); Collaborative Innovation Center of Tianjin for Medical Epigenetics and Department of Physiology and Pathophysiology, Tianjin Medical University, Tianjin, China
| | - Chunjiong Wang
- 1Tianjin Key Laboratory of Metabolic Diseases; Key Laboratory of Immune Microenvironment and Disease (Ministry of Education); Collaborative Innovation Center of Tianjin for Medical Epigenetics and Department of Physiology and Pathophysiology, Tianjin Medical University, Tianjin, China
| | - Ding Ai
- 1Tianjin Key Laboratory of Metabolic Diseases; Key Laboratory of Immune Microenvironment and Disease (Ministry of Education); Collaborative Innovation Center of Tianjin for Medical Epigenetics and Department of Physiology and Pathophysiology, Tianjin Medical University, Tianjin, China
| | - Bruce D. Hammock
- 3Department of Entomology and Nematology and University of California, Davis Comprehensive Cancer Center, Davis, California
| | - Yi Zhu
- 1Tianjin Key Laboratory of Metabolic Diseases; Key Laboratory of Immune Microenvironment and Disease (Ministry of Education); Collaborative Innovation Center of Tianjin for Medical Epigenetics and Department of Physiology and Pathophysiology, Tianjin Medical University, Tianjin, China
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9
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Quines CB, Jardim NS, Araujo PCO, Cechella JL, Prado VC, Nogueira CW. Resistance training restores metabolic alterations induced by monosodium glutamate in a sex-dependent manner in male and female rats. J Cell Biochem 2019; 120:13426-13440. [PMID: 30916837 DOI: 10.1002/jcb.28617] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2018] [Revised: 01/14/2019] [Accepted: 01/28/2019] [Indexed: 01/07/2023]
Abstract
Despite resistance exercises being associated with health outcomes, numerous issues are still unresolved and further research is required before the exercise can faithfully be prescribed as medicine. The goal of this study was to investigate whether there are sex differences in resistance training effects on metabolic alterations induced by monosodium glutamate (MSG), a model of obesity, in male and female rats. Male and female Wistar rats received MSG (4 g/kg body weight/day, s.c.) from postnatal day 1 to 10. After 10 days from MSG administration, the rats were separated into two groups: MSG-sedentary and MSG-exercised. At postnatal day 60, the animals started a resistance training protocol in an 80 degrees inclined vertical ladder apparatus and performed it for 7 weeks. Control rats received saline solution and were divided in saline-sedentary and saline-exercised. Resistance training restored all plasma biochemical parameters (glucose, cholesterol, triglycerides, aspartate aminotransferase, and alanine aminotransferase) increased in male and female rats treated with MSG. The MSG administration induced hyperglycemia associated with a decrease in the skeletal muscle glucose transporter 4 (GLUT4) levels and accompanied by deregulation in proteins, G-6Pase, and tyrosine aminotransferase, involved in hepatic glucose metabolism of male and female rats. MSG induced dyslipidemia and lipotoxicity in the liver and skeletal muscle of male rats. Regarding female rats, lipotoxicity was found only in the skeletal muscle. The resistance training had beneficial effects against metabolic alterations induced by MSG in male and female rats, through regulation of proteins (GLUT2, protein kinase B, and GLUT4) involved in glucose and lipid pathways in the liver and skeletal muscle.
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Affiliation(s)
- Caroline B Quines
- Departamento de Bioquímica e Biologia Molecular, Laboratório de Síntese, Reatividade e Avaliação Farmacológica e Toxicológica de Organocalcogênios, Centro de Ciências Naturais e Exatas, Universidade Federal de Santa Maria, Santa Maria, Rio Grande do Sul, Brazil
| | - Natália S Jardim
- Departamento de Bioquímica e Biologia Molecular, Laboratório de Síntese, Reatividade e Avaliação Farmacológica e Toxicológica de Organocalcogênios, Centro de Ciências Naturais e Exatas, Universidade Federal de Santa Maria, Santa Maria, Rio Grande do Sul, Brazil
| | - Paulo Cesar O Araujo
- Departamento de Bioquímica e Biologia Molecular, Laboratório de Síntese, Reatividade e Avaliação Farmacológica e Toxicológica de Organocalcogênios, Centro de Ciências Naturais e Exatas, Universidade Federal de Santa Maria, Santa Maria, Rio Grande do Sul, Brazil
| | - José Luiz Cechella
- Departamento de Bioquímica e Biologia Molecular, Laboratório de Síntese, Reatividade e Avaliação Farmacológica e Toxicológica de Organocalcogênios, Centro de Ciências Naturais e Exatas, Universidade Federal de Santa Maria, Santa Maria, Rio Grande do Sul, Brazil
| | - Vinicius C Prado
- Departamento de Bioquímica e Biologia Molecular, Laboratório de Síntese, Reatividade e Avaliação Farmacológica e Toxicológica de Organocalcogênios, Centro de Ciências Naturais e Exatas, Universidade Federal de Santa Maria, Santa Maria, Rio Grande do Sul, Brazil
| | - Cristina W Nogueira
- Departamento de Bioquímica e Biologia Molecular, Laboratório de Síntese, Reatividade e Avaliação Farmacológica e Toxicológica de Organocalcogênios, Centro de Ciências Naturais e Exatas, Universidade Federal de Santa Maria, Santa Maria, Rio Grande do Sul, Brazil
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10
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Konopelniuk V, Falalyeyeva T, Tsyryuk O, Savchenko Y, Prybytko I, Kobyliak N, Kovalchuk O, Boyko A, Arkhipov VV, Moroz Y, Ostapchenko L. The correction of the metabolic parameters of msg-induced obesity in rats by 2-[4-(benzyloxy) phenoxy] acetic acid. JOURNAL OF NUTRITION & INTERMEDIARY METABOLISM 2018. [DOI: 10.1016/j.jnim.2018.07.002] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/28/2022] Open
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11
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Quines CB, Rosa SG, Velasquez D, Prado VC, Neto JS, Nogueira CW. (p-ClPhSe)2 stabilizes metabolic function in a rat model of neuroendocrine obesity induced by monosodium glutamate. Food Chem Toxicol 2018; 118:168-180. [DOI: 10.1016/j.fct.2018.05.010] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2017] [Revised: 04/30/2018] [Accepted: 05/04/2018] [Indexed: 12/13/2022]
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12
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Khaleel EF, Abdel-Aleem GA, Mostafa DG. Resveratrol improves high-fat diet induced fatty liver and insulin resistance by concomitantly inhibiting proteolytic cleavage of sterol regulatory element-binding proteins, free fatty acid oxidation, and intestinal triglyceride absorption. Can J Physiol Pharmacol 2018; 96:145-157. [DOI: 10.1139/cjpp-2017-0001] [Citation(s) in RCA: 25] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
Resveratrol (RES) has the ability to ameliorate nonalcoholic fatty liver disease (NAFLD) and the mechanism remains unclear. Hence, using high-fat diet (HFD) obese rat model, we investigated the effect of a low dose of RES (20 mg/kg) on the hepatic sterol regulatory element-binding protein (SREBPs) – lipogenesis pathway, enzymes involved in β-oxidation and activity of pancreatic lipase. Four groups of rats (n = 8) of control (12% of calories as fat) and HFD (40% of calories as fat) were administered orally with either normal saline as a vehicle or RES as a concomitant treatment for 8 weeks on a daily basis. Then, various biochemical, histological, and molecular experiments were carried out. RES prevented the development and progression of NAFLD and significantly improved insulin sensitivity through (1) inhibiting the proteolytic cleavage of SREBPs-1 and SREBPs-2 without affecting their precursor mRNA or protein levels, (2) inhibiting free fatty acid β-oxidation and generation of reactive oxygen species through significant inhibition of CPT-1 and UCP-2, and (3) decreasing activity of pancreatic lipase in vivo and in vitro. In conclusion, our findings are the first in the literature to show new mechanisms of the hepatoprotective effect of RES against HFD induced NAFLD in rats.
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Affiliation(s)
- Eman F. Khaleel
- Department of Medical Physiology, Faculty of Medicine, Cairo University, Cairo, Egypt
- Department of Medical Physiology, College of Medicine, King Khalid University, P.O. Box 3340, Abha 61421, Saudi Arabia
| | - Ghada A. Abdel-Aleem
- Department of Medical Biochemistry, Faculty of Medicine, Tanta University, Tanta, Egypt
- Department of Medical Biochemistry, College of Medicine, King Khalid University, P.O. Box 3340, Abha 61421, Saudi Arabia
| | - Dalia G. Mostafa
- Department of Medical Physiology, College of Medicine, King Khalid University, P.O. Box 3340, Abha 61421, Saudi Arabia
- Department of Medical Physiology, Faculty of Medicine, Assiut University, Assiut, Egypt
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13
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Leão VF, Ferreira LLDM, Melo CM, Bonfleur ML, da Silva LL, Carneiro EM, Raimundo JM, Ribeiro RA. Taurine supplementation prevents endothelial dysfunction and attenuates structural changes in aortas from hypothalamic obese rats. Eur J Nutr 2018; 58:551-563. [DOI: 10.1007/s00394-018-1616-2] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2017] [Accepted: 01/14/2018] [Indexed: 02/07/2023]
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14
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Monosodium glutamate affects cognitive functions in male albino rats. EGYPTIAN JOURNAL OF FORENSIC SCIENCES 2018. [DOI: 10.1186/s41935-018-0038-x] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022] Open
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15
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Goetzman ES, Prochownik EV. The Role for Myc in Coordinating Glycolysis, Oxidative Phosphorylation, Glutaminolysis, and Fatty Acid Metabolism in Normal and Neoplastic Tissues. Front Endocrinol (Lausanne) 2018; 9:129. [PMID: 29706933 PMCID: PMC5907532 DOI: 10.3389/fendo.2018.00129] [Citation(s) in RCA: 132] [Impact Index Per Article: 22.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/19/2018] [Accepted: 03/13/2018] [Indexed: 12/24/2022] Open
Abstract
That cancer cells show patterns of metabolism different from normal cells has been known for over 50 years. Yet, it is only in the past decade or so that an appreciation of the benefits of these changes has begun to emerge. Altered cancer cell metabolism was initially attributed to defective mitochondria. However, we now realize that most cancers do not have mitochondrial mutations and that normal cells can transiently adopt cancer-like metabolism during periods of rapid proliferation. Indeed, an encompassing, albeit somewhat simplified, conceptual framework to explain both normal and cancer cell metabolism rests on several simple premises. First, the metabolic pathways used by cancer cells and their normal counterparts are the same. Second, normal quiescent cells use their metabolic pathways and the energy they generate largely to maintain cellular health and organelle turnover and, in some cases, to provide secreted products necessary for the survival of the intact organism. By contrast, undifferentiated cancer cells minimize the latter functions and devote their energy to producing the anabolic substrates necessary to maintain high rates of unremitting cellular proliferation. Third, as a result of the uncontrolled proliferation of cancer cells, a larger fraction of the metabolic intermediates normally used by quiescent cells purely as a source of energy are instead channeled into competing proliferation-focused and energy-consuming anabolic pathways. Fourth, cancer cell clones with the most plastic and rapidly adaptable metabolism will eventually outcompete their less well-adapted brethren during tumor progression and evolution. This attribute becomes increasingly important as tumors grow and as their individual cells compete in a constantly changing and inimical environment marked by nutrient, oxygen, and growth factor deficits. Here, we review some of the metabolic pathways whose importance has gained center stage for tumor growth, particularly those under the control of the c-Myc (Myc) oncoprotein. We discuss how these pathways differ functionally between quiescent and proliferating normal cells, how they are kidnapped and corrupted during the course of transformation, and consider potential therapeutic strategies that take advantage of common features of neoplastic and metabolic disorders.
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Affiliation(s)
- Eric S. Goetzman
- Division of Medical Genetics, Children’s Hospital of Pittsburgh of UPMC, Pittsburgh, PA, United States
| | - Edward V. Prochownik
- Division of Hematology/Oncology, Children’s Hospital of Pittsburgh of UPMC, Pittsburgh, PA, United States
- Department of Microbiology and Molecular Genetics, University of Pittsburgh Medical Center, Pittsburgh, PA, United States
- University of Pittsburgh Hillman Cancer Center, Pittsburgh, PA, United States
- *Correspondence: Edward V. Prochownik,
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16
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Dietaryα-lactalbumin induced fatty liver by enhancing nuclear liver X receptorαβ/sterol regulatory element-binding protein-1c/PPARγexpression and minimising PPARα/carnitine palmitoyltransferase-1 expression and AMP-activated protein kinaseαphosphorylation associated with atherogenic dyslipidaemia, insulin resistance and oxidative stress in Balb/c mice. Br J Nutr 2017; 118:914-929. [DOI: 10.1017/s000711451700232x] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
AbstractThe effect and the role played by dietaryα-lactalbumin (α-LAC) on hepatic fat metabolism are yet to be fully elucidated. We reported previously thatα-LAC intake induced atherogenic dyslipidaemia in Balb/c mice. The aim of the present study was to investigate if this atherogenic effect could be due to a possibleα-LAC-induced hepatic steatosis. We examine the ability of dietaryα-LAC to induce liver steatosis, identifying the molecular mechanisms underlying hepatic lipid metabolism in association with the lipid profile, peripheral insulin resistance (IR) and changes in the hepatic oxidative environment. Male Balb/c mice (n6) were fed with diets containing either chow or 14 %α-LAC for 4 weeks. Theα-LAC-fed mice developed abdominal adiposity and IR. Moderate liver steatosis with increased TAG and NEFA contents was correlated with atherogenic dyslipidaemia. There was increased nuclear expression of liver X receptorαβ(LXRαβ), sterol regulatory element-binding protein-1c (SREBP-1c) and PPARγtranscription factors and of the cytosolic enzymes acetyl-CoA carboxylase 1 (ACC1) and fatty acid synthase involved in the hepaticde novolipogenesis. The opposite was found for the nuclear receptor PPARαand the mitochondrial enzyme carnitine palmitoyltransferase-1 (CPT-1), leading to reduced fatty acidβ-oxidation (FAO). These changes were associated with a significant decrease in both p-Thr172-AMP-activated protein kinaseα(AMPKα) (inactivation) and p-Ser79-ACC1 (activation) and with a more oxidative liver environment increasing lipid peroxidation and protein oxidation and reducing GSH:GSSG ratio in theα-LAC-fed mice. In conclusion, 4 weeks of 14 %α-LAC feeding induced liver steatosis associated with atherogenic dyslipidaemia, IR and oxidative stress by enhancing nuclear LXRαβ/SREBP-1c/PPARγexpression and diminishing PPARα/CPT-1 expression and AMPKαphosphorylation shifting the hepatic FAO toward fatty acid synthesis in Balb/c mice.
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17
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Quines CB, Chagas PM, Hartmann D, Carvalho NR, Soares FA, Nogueira CW. (p
-ClPhSe)2
Reduces Hepatotoxicity Induced by Monosodium Glutamate by Improving Mitochondrial Function in Rats. J Cell Biochem 2017; 118:2877-2886. [DOI: 10.1002/jcb.25938] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2017] [Accepted: 02/15/2017] [Indexed: 12/11/2022]
Affiliation(s)
- Caroline B. Quines
- Laboratório de Síntese, Reatividade e Avaliação Farmacológica e Toxicológica de Organocalcogênios, Centro de Ciências Naturais e Exatas, Departamento de Bioquímica e Biologia Molecular; Universidade Federal de Santa Maria; Santa Maria CEP 97105-900, RS Brazil
| | - Pietro M. Chagas
- Laboratório de Síntese, Reatividade e Avaliação Farmacológica e Toxicológica de Organocalcogênios, Centro de Ciências Naturais e Exatas, Departamento de Bioquímica e Biologia Molecular; Universidade Federal de Santa Maria; Santa Maria CEP 97105-900, RS Brazil
| | - Diane Hartmann
- Departamento de Bioquímica e Biologia Molecular, Centro de Ciências Naturais e Exatas, Universidade Federal de Santa Maria; Campus UFSM; Santa Maria RS 97105-900 Brazil
| | - Nélson R. Carvalho
- Departamento de Bioquímica e Biologia Molecular, Centro de Ciências Naturais e Exatas, Universidade Federal de Santa Maria; Campus UFSM; Santa Maria RS 97105-900 Brazil
| | - Félix A. Soares
- Departamento de Bioquímica e Biologia Molecular, Centro de Ciências Naturais e Exatas, Universidade Federal de Santa Maria; Campus UFSM; Santa Maria RS 97105-900 Brazil
| | - Cristina W. Nogueira
- Laboratório de Síntese, Reatividade e Avaliação Farmacológica e Toxicológica de Organocalcogênios, Centro de Ciências Naturais e Exatas, Departamento de Bioquímica e Biologia Molecular; Universidade Federal de Santa Maria; Santa Maria CEP 97105-900, RS Brazil
- Departamento de Bioquímica e Biologia Molecular, Centro de Ciências Naturais e Exatas, Universidade Federal de Santa Maria; Campus UFSM; Santa Maria RS 97105-900 Brazil
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18
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Ashworth WB, Davies NA, Bogle IDL. A Computational Model of Hepatic Energy Metabolism: Understanding Zonated Damage and Steatosis in NAFLD. PLoS Comput Biol 2016; 12:e1005105. [PMID: 27632189 PMCID: PMC5025084 DOI: 10.1371/journal.pcbi.1005105] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2015] [Accepted: 08/12/2016] [Indexed: 12/20/2022] Open
Abstract
In non-alcoholic fatty liver disease (NAFLD), lipid build-up and the resulting damage is known to occur more severely in pericentral cells. Due to the complexity of studying individual regions of the sinusoid, the causes of this zone specificity and its implications on treatment are largely ignored. In this study, a computational model of liver glucose and lipid metabolism is presented which treats the sinusoid as the repeating unit of the liver rather than the single hepatocyte. This allows for inclusion of zonated enzyme expression by splitting the sinusoid into periportal to pericentral compartments. By simulating insulin resistance (IR) and high intake diets leading to the development of steatosis in the model, we identify key differences between periportal and pericentral cells accounting for higher susceptibility to pericentral steatosis. Secondly, variation between individuals is seen in both susceptibility to steatosis and in its development across the sinusoid. Around 25% of obese individuals do not show excess liver fat, whilst 16% of lean individuals develop NAFLD. Furthermore, whilst pericentral cells tend to show higher lipid levels, variation is seen in the predominant location of steatosis from pericentral to pan-sinusoidal or azonal. Sensitivity analysis was used to identify the processes which have the largest effect on both total hepatic triglyceride levels and on the sinusoidal location of steatosis. As is seen in vivo, steatosis occurs when simulating IR in the model, predominantly due to increased uptake, along with an increase in de novo lipogenesis. Additionally, concentrations of glucose intermediates including glycerol-3-phosphate increased when simulating IR due to inhibited glycogen synthesis. Several differences between zones contributed to a higher susceptibility to steatosis in pericentral cells in the model simulations. Firstly, the periportal zonation of both glycogen synthase and the oxidative phosphorylation enzymes meant that the build-up of glucose intermediates was less severe in the periportal hepatocyte compartments. Secondly, the periportal zonation of the enzymes mediating β-oxidation and oxidative phosphorylation resulted in excess fats being metabolised more rapidly in the periportal hepatocyte compartments. Finally, the pericentral expression of de novo lipogenesis contributed to pericentral steatosis when additionally simulating the increase in sterol-regulatory element binding protein 1c (SREBP-1c) seen in NAFLD patients in vivo. The hepatic triglyceride concentration was predicted to be most sensitive to inter-individual variation in the activity of enzymes which, either directly or indirectly, determine the rate of free fatty acid (FFA) oxidation. The concentration was most strongly dependent on the rate constants for β-oxidation and oxidative phosphorylation. It also showed moderate sensitivity to the rate constants for processes which alter the allosteric inhibition of β-oxidation by acetyl-CoA. The predominant sinusoidal location of steatosis meanwhile was most sensitive variations in the zonation of proteins mediating FFA uptake or triglyceride release as very low density lipoproteins (VLDL). Neither the total hepatic concentration nor the location of steatosis showed strong sensitivity to variations in the lipogenic rate constants.
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Affiliation(s)
- William B. Ashworth
- Institute of Liver and Digestive Health, University College London, London, United Kingdom
- Department of Chemical Engineering, University College London, London, United Kingdom
- CoMPLEX, University College London, London, United Kingdom
| | - Nathan A. Davies
- Institute of Liver and Digestive Health, University College London, London, United Kingdom
| | - I. David L. Bogle
- Department of Chemical Engineering, University College London, London, United Kingdom
- * E-mail:
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19
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Patterson RE, Kalavalapalli S, Williams CM, Nautiyal M, Mathew JT, Martinez J, Reinhard MK, McDougall DJ, Rocca JR, Yost RA, Cusi K, Garrett TJ, Sunny NE. Lipotoxicity in steatohepatitis occurs despite an increase in tricarboxylic acid cycle activity. Am J Physiol Endocrinol Metab 2016; 310:E484-94. [PMID: 26814015 PMCID: PMC4824140 DOI: 10.1152/ajpendo.00492.2015] [Citation(s) in RCA: 113] [Impact Index Per Article: 14.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/17/2015] [Accepted: 01/25/2016] [Indexed: 02/07/2023]
Abstract
The hepatic tricarboxylic acid (TCA) cycle is central to integrating macronutrient metabolism and is closely coupled to cellular respiration, free radical generation, and inflammation. Oxidative flux through the TCA cycle is induced during hepatic insulin resistance, in mice and humans with simple steatosis, reflecting early compensatory remodeling of mitochondrial energetics. We hypothesized that progressive severity of hepatic insulin resistance and the onset of nonalcoholic steatohepatitis (NASH) would impair oxidative flux through the hepatic TCA cycle. Mice (C57/BL6) were fed a high-trans-fat high-fructose diet (TFD) for 8 wk to induce simple steatosis and NASH by 24 wk. In vivo fasting hepatic mitochondrial fluxes were determined by(13)C-nuclear magnetic resonance (NMR)-based isotopomer analysis. Hepatic metabolic intermediates were quantified using mass spectrometry-based targeted metabolomics. Hepatic triglyceride accumulation and insulin resistance preceded alterations in mitochondrial metabolism, since TCA cycle fluxes remained normal during simple steatosis. However, mice with NASH had a twofold induction (P< 0.05) of mitochondrial fluxes (μmol/min) through the TCA cycle (2.6 ± 0.5 vs. 5.4 ± 0.6), anaplerosis (9.1 ± 1.2 vs. 16.9 ± 2.2), and pyruvate cycling (4.9 ± 1.0 vs. 11.1 ± 1.9) compared with their age-matched controls. Induction of the TCA cycle activity during NASH was concurrent with blunted ketogenesis and accumulation of hepatic diacylglycerols (DAGs), ceramides (Cer), and long-chain acylcarnitines, suggesting inefficient oxidation and disposal of excess free fatty acids (FFA). Sustained induction of mitochondrial TCA cycle failed to prevent accretion of "lipotoxic" metabolites in the liver and could hasten inflammation and the metabolic transition to NASH.
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Affiliation(s)
| | - Srilaxmi Kalavalapalli
- Division of Endocrinology, Diabetes, and Metabolism, Department of Medicine, University of Florida, Gainesville, Florida
| | - Caroline M Williams
- Department of Integrative Biology, University of California, Berkeley, California
| | - Manisha Nautiyal
- Division of Endocrinology, Diabetes, and Metabolism, Department of Medicine, University of Florida, Gainesville, Florida
| | - Justin T Mathew
- Division of Endocrinology, Diabetes, and Metabolism, Department of Medicine, University of Florida, Gainesville, Florida
| | - Janie Martinez
- Division of Endocrinology, Diabetes, and Metabolism, Department of Medicine, University of Florida, Gainesville, Florida
| | - Mary K Reinhard
- Animal Care Services, University of Florida, Gainesville, Florida
| | | | - James R Rocca
- Advanced Magnetic Resonance Imaging and Spectroscopy Facility, McKnight Brain Institute, University of Florida, Gainesville, Florida
| | - Richard A Yost
- Department of Chemistry, University of Florida, Gainesville, Florida; Department of Pathology, University of Florida, Gainesville, Florida
| | - Kenneth Cusi
- Division of Endocrinology, Diabetes, and Metabolism, Department of Medicine, University of Florida, Gainesville, Florida; Division of Endocrinology, Diabetes, and Metabolism, Malcom Randall Veterans Administration Medical Center, Gainesville, Florida; Division of Diabetes, the University of Texas Health Science Center at San Antonio, San Antonio, Texas; Division of Diabetes, Audie L. Murphy Veterans Administration Medical Center, San Antonio, Texas; and
| | - Timothy J Garrett
- Department of Pathology, University of Florida, Gainesville, Florida
| | - Nishanth E Sunny
- Division of Endocrinology, Diabetes, and Metabolism, Department of Medicine, University of Florida, Gainesville, Florida;
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Villagarcía HG, Sabugo V, Castro MC, Schinella G, Castrogiovanni D, Spinedi E, Massa ML, Francini F. Chronic Glucocorticoid-Rich Milieu and Liver Dysfunction. Int J Endocrinol 2016; 2016:7838290. [PMID: 27597864 PMCID: PMC4997070 DOI: 10.1155/2016/7838290] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/31/2016] [Revised: 06/30/2016] [Accepted: 07/12/2016] [Indexed: 01/08/2023] Open
Abstract
We investigated the impact of chronic hypercorticosteronemia (due to neonatal monosodium L-glutamate, MSG, and treatment) on liver oxidative stress (OS), inflammation, and carbohydrate/lipid metabolism in adult male rats. We evaluated the peripheral concentrations of several metabolic and OS markers and insulin resistance indexes. In liver we assessed (a) OS (GSH and protein carbonyl groups) and inflammatory (IL-1b, TNFa, and PAI-1) biomarkers and (b) carbohydrate and lipid metabolisms. MSG rats displayed degenerated optic nerves, hypophagia, low body and liver weights, and enlarged adipose tissue mass; higher peripheral levels of glucose, triglycerides, insulin, uric acid, leptin, corticosterone, transaminases and TBARS, and peripheral and liver insulin resistance; elevated liver OS, inflammation markers, and glucokinase (mRNA/activity) and fructokinase (mRNA). Additionally, MSG liver phosphofructokinase-2, glucose-6-phosphatase (mRNA and activity) and glucose-6-phosphate dehydrogenase, Chrebp, Srebp1c, fatty acid synthase, and glycerol-3-phosphate (mRNAs) were increased. In conclusion adult MSG rats developed an insulin-resistant state and increased OS and serious hepatic dysfunction characterized by inflammation and metabolic signs suggesting increased lipogenesis. These features, shared by both metabolic and Cushing's syndrome human phenotypes, support that a chronic glucocorticoid-rich endogenous environment mainly impacts on hepatic glucose cycle, displacing local metabolism to lipogenesis. Whether correcting the glucocorticoid-rich environment ameliorates such dysfunctions requires further investigation.
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Affiliation(s)
| | - Vanesa Sabugo
- Centro de Endocrinología Experimental y Aplicada (CENEXA), UNLP-CONICET-FCM, 1900 La Plata, Argentina
| | - María Cecilia Castro
- Centro de Endocrinología Experimental y Aplicada (CENEXA), UNLP-CONICET-FCM, 1900 La Plata, Argentina
| | - Guillermo Schinella
- Cátedra de Farmacología Básica, Facultad de Ciencias Médicas, UNLP and CICPBA, 1900 La Plata, Argentina
| | - Daniel Castrogiovanni
- Instituto Multidisciplinario de Biología Celular (IMBICE), CONICET-CICPBA-UNLP, 1900 La Plata, Argentina
| | - Eduardo Spinedi
- Centro de Endocrinología Experimental y Aplicada (CENEXA), UNLP-CONICET-FCM, 1900 La Plata, Argentina
| | - María Laura Massa
- Centro de Endocrinología Experimental y Aplicada (CENEXA), UNLP-CONICET-FCM, 1900 La Plata, Argentina
| | - Flavio Francini
- Centro de Endocrinología Experimental y Aplicada (CENEXA), UNLP-CONICET-FCM, 1900 La Plata, Argentina
- *Flavio Francini:
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21
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Quines CB, Rosa SG, Chagas PM, da Rocha JT, Dobrachinski F, Carvalho NR, Soares FA, da Luz SCA, Nogueira CW. Homeostatic effect of p-chloro-diphenyl diselenide on glucose metabolism and mitochondrial function alterations induced by monosodium glutamate administration to rats. Amino Acids 2015; 48:137-48. [DOI: 10.1007/s00726-015-2073-3] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2015] [Accepted: 08/13/2015] [Indexed: 10/23/2022]
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22
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Deminice R, de Castro GSF, Francisco LV, da Silva LECM, Cardoso JFR, Frajacomo FTT, Teodoro BG, Dos Reis Silveira L, Jordao AA. Creatine supplementation prevents fatty liver in rats fed choline-deficient diet: a burden of one-carbon and fatty acid metabolism. J Nutr Biochem 2015; 26:391-7. [PMID: 25649792 DOI: 10.1016/j.jnutbio.2014.11.014] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2014] [Revised: 11/05/2014] [Accepted: 11/19/2014] [Indexed: 02/06/2023]
Abstract
AIM To examine the effects of creatine (Cr) supplementation on liver fat accumulation in rats fed a choline-deficient diet. METHODS Twenty-four rats were divided into 3 groups of 8 based on 4 weeks of feeding an AIN-93 control diet (C), a choline-deficient diet (CDD) or a CDD supplemented with 2% Cr. The CDD diet was AIN-93 without choline. RESULTS The CDD significantly increased plasma homocysteine and TNFα concentration, as well as ALT activity. In liver, the CDD enhanced concentrations of total fat (55%), cholesterol (25%), triglycerides (87%), MDA (30%), TNFα (241%) and decreased SAM concentrations (25%) and the SAM/SAH ratio (33%). Cr supplementation prevented all these metabolic changes, except for hepatic SAM and the SAM/SAH ratio. However, no changes in PEMT gene expression or liver phosphatidylcholine levels were observed among the three experimental groups, and there were no changes in hepatic triglyceride transfer protein (MTP) mRNA level. On the contrary, Cr supplementation normalized expression of the transcription factors PPARα and PPARγ that were altered by the CDD. Further, the downstream targets and fatty acids metabolism genes, UCP2, LCAD and CPT1a, were also normalized in the Cr group as compared to CDD-fed rats. CONCLUSION Cr supplementation prevented fat liver accumulation and hepatic injures in rats fed with a CDD for 4 weeks. Our results demonstrated that one-carbon metabolism may have a small role in mitigating hepatic fat accumulation by Cr supplementation. The modulation of key genes related to fatty acid oxidation pathway suggests a new mechanism by which Cr prevents liver fat accumulation.
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Affiliation(s)
- Rafael Deminice
- Nutrition and Metabolism, Faculty of Medicine of Ribeirao Preto, University of Sao Paulo, Av. Bandeirantes 3900, Ribeirao Preto, Sao Paulo, Brazil; Department of Physical Education, Faculty of Physical Education and Sport, State University of Londrina. Rodovia Celso Garcia Cid
- Pr 445 Km 380
- Campus Universitário, Londrina, Paraná, Brazil.
| | - Gabriela Salim Ferreira de Castro
- Nutrition and Metabolism, Faculty of Medicine of Ribeirao Preto, University of Sao Paulo, Av. Bandeirantes 3900, Ribeirao Preto, Sao Paulo, Brazil
| | - Lucas Vieira Francisco
- Nutrition and Metabolism, Faculty of Medicine of Ribeirao Preto, University of Sao Paulo, Av. Bandeirantes 3900, Ribeirao Preto, Sao Paulo, Brazil
| | - Lilian Eslaine Costa Mendes da Silva
- Nutrition and Metabolism, Faculty of Medicine of Ribeirao Preto, University of Sao Paulo, Av. Bandeirantes 3900, Ribeirao Preto, Sao Paulo, Brazil
| | - João Felipe Rito Cardoso
- Nutrition and Metabolism, Faculty of Medicine of Ribeirao Preto, University of Sao Paulo, Av. Bandeirantes 3900, Ribeirao Preto, Sao Paulo, Brazil
| | - Fernando Tadeu Trevisan Frajacomo
- Nutrition and Metabolism, Faculty of Medicine of Ribeirao Preto, University of Sao Paulo, Av. Bandeirantes 3900, Ribeirao Preto, Sao Paulo, Brazil
| | - Bruno Gonzaga Teodoro
- Department of Biochesmtry and Imunology, Faculty of Medicine of Ribeirão Preto Av. Bandeirantes 3900, Ribeirao Preto, Sao Paulo, Brazil
| | - Leonardo Dos Reis Silveira
- School of Physical Education of Ribeirao Preto, University of Sao Paulo, Av. Bandeirantes 3900, Ribeirao Preto, Sao Paulo, Brazil; Department of Biochesmtry and Imunology, Faculty of Medicine of Ribeirão Preto Av. Bandeirantes 3900, Ribeirao Preto, Sao Paulo, Brazil
| | - Alceu Afonso Jordao
- Nutrition and Metabolism, Faculty of Medicine of Ribeirao Preto, University of Sao Paulo, Av. Bandeirantes 3900, Ribeirao Preto, Sao Paulo, Brazil
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Bakshi MV, Azimzadeh O, Barjaktarovic Z, Kempf SJ, Merl-Pham J, Hauck SM, Buratovic S, Eriksson P, Atkinson MJ, Tapio S. Total Body Exposure to Low-Dose Ionizing Radiation Induces Long-Term Alterations to the Liver Proteome of Neonatally Exposed Mice. J Proteome Res 2014; 14:366-73. [DOI: 10.1021/pr500890n] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Affiliation(s)
| | | | | | | | | | | | - Sonja Buratovic
- Department
of Environmental Toxicology, Uppsala University, 75236 Uppsala, Sweden
| | - Per Eriksson
- Department
of Environmental Toxicology, Uppsala University, 75236 Uppsala, Sweden
| | - Michael J. Atkinson
- Chair
of Radiation Biology, Technical University of Munich, 81675 Munich, Germany
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Nonalcoholic Fatty liver disease: pathogenesis and therapeutics from a mitochondria-centric perspective. OXIDATIVE MEDICINE AND CELLULAR LONGEVITY 2014; 2014:637027. [PMID: 25371775 PMCID: PMC4211163 DOI: 10.1155/2014/637027] [Citation(s) in RCA: 107] [Impact Index Per Article: 10.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/14/2014] [Revised: 07/31/2014] [Accepted: 07/31/2014] [Indexed: 12/12/2022]
Abstract
Nonalcoholic fatty liver disease (NAFLD) describes a spectrum of disorders characterized by the accumulation of triglycerides within the liver. The global prevalence of NAFLD has been increasing as the obesity epidemic shows no sign of relenting. Mitochondria play a central role in hepatic lipid metabolism and also are affected by upstream signaling pathways involved in hepatic metabolism. This review will focus on the role of mitochondria in the pathophysiology of NAFLD and touch on some of the therapeutic approaches targeting mitochondria as well as metabolically important signaling pathways. Mitochondria are able to adapt to lipid accumulation in hepatocytes by increasing rates of beta-oxidation; however increased substrate delivery to the mitochondrial electron transport chain (ETC) leads to increased reactive oxygen species (ROS) production and eventually ETC dysfunction. Decreased ETC function combined with increased rates of fatty acid beta-oxidation leads to the accumulation of incomplete products of beta-oxidation, which combined with increased levels of ROS contribute to insulin resistance. Several related signaling pathways, nuclear receptors, and transcription factors also regulate hepatic lipid metabolism, many of which are redox sensitive and regulated by ROS.
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25
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Zou X, Yan C, Shi Y, Cao K, Xu J, Wang X, Chen C, Luo C, Li Y, Gao J, Pang W, Zhao J, Zhao F, Li H, Zheng A, Sun W, Long J, Szeto IMY, Zhao Y, Dong Z, Zhang P, Wang J, Lu W, Zhang Y, Liu J, Feng Z. Mitochondrial dysfunction in obesity-associated nonalcoholic fatty liver disease: the protective effects of pomegranate with its active component punicalagin. Antioxid Redox Signal 2014; 21:1557-70. [PMID: 24393106 PMCID: PMC4175030 DOI: 10.1089/ars.2013.5538] [Citation(s) in RCA: 95] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
AIMS Punicalagin (PU) is one of the major ellagitannins found in the pomegranate (Punica granatum), which is a popular fruit with several health benefits. So far, no studies have evaluated the effects of PU on nonalcoholic fatty liver disease (NAFLD). Our work aims at studying the effect of PU-enriched pomegranate extract (PE) on high fat diet (HFD)-induced NAFLD. RESULTS PE administration at a dosage of 150 mg/kg/day significantly inhibited HFD-induced hyperlipidemia and hepatic lipid deposition. As major contributors to NAFLD, increased expression of pro-inflammatory cytokines such as tumor necrosis factor-alpha, interleukins 1, 4, and 6 as well as augmented oxidative stress in hepatocytes followed by nuclear factor (erythroid-derived-2)-like 2 (Nrf2) activation were normalized through PE supplementation. In addition, PE treatment reduced uncoupling protein 2 (UCP2) expression, restored ATP content, suppressed mitochondrial protein oxidation, and improved mitochondrial complex activity in the liver. In contrast, mitochondrial content was not affected despite increased peroxisomal proliferator-activated receptor-gamma coactivator-1α (PGC-1α) and elevated expression of genes related to mitochondrial beta-oxidation after PE treatment. Finally, PU was identified as the predominant active component of PE with regard to the lowering of triglyceride and cholesterol content in HepG2 cells, and both PU- and PE-protected cells from palmitate induced mitochondrial dysfunction and insulin resistance. INNOVATION Our work presents the beneficial effects of PE on obesity-associated NAFLD and multiple risk factors. PU was proposed to be the major active component. CONCLUSIONS By promoting mitochondrial function, eliminating oxidative stress and inflammation, PU may be a useful nutrient for the treatment of NAFLD.
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Affiliation(s)
- Xuan Zou
- 1 The Key Laboratory of Biomedical Information Engineering of Ministry of Education, School of Life Science and Technology, Frontier Institute of Science and Technology, Xi'an Jiaotong University , Xi'an, China
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26
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Li H, Deng Z, Liu R, Loewen S, Tsao R. Bioaccessibility, in vitro antioxidant activities and in vivo anti-inflammatory activities of a purple tomato (Solanum lycopersicum L.). Food Chem 2014; 159:353-60. [DOI: 10.1016/j.foodchem.2014.03.023] [Citation(s) in RCA: 56] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2013] [Revised: 02/26/2014] [Accepted: 03/04/2014] [Indexed: 01/04/2023]
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27
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Mailloux RJ, Jin X, Willmore WG. Redox regulation of mitochondrial function with emphasis on cysteine oxidation reactions. Redox Biol 2013; 2:123-39. [PMID: 24455476 PMCID: PMC3895620 DOI: 10.1016/j.redox.2013.12.011] [Citation(s) in RCA: 210] [Impact Index Per Article: 19.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2013] [Accepted: 12/13/2013] [Indexed: 12/13/2022] Open
Abstract
Mitochondria have a myriad of essential functions including metabolism and apoptosis. These chief functions are reliant on electron transfer reactions and the production of ATP and reactive oxygen species (ROS). The production of ATP and ROS are intimately linked to the electron transport chain (ETC). Electrons from nutrients are passed through the ETC via a series of acceptor and donor molecules to the terminal electron acceptor molecular oxygen (O2) which ultimately drives the synthesis of ATP. Electron transfer through the respiratory chain and nutrient oxidation also produces ROS. At high enough concentrations ROS can activate mitochondrial apoptotic machinery which ultimately leads to cell death. However, if maintained at low enough concentrations ROS can serve as important signaling molecules. Various regulatory mechanisms converge upon mitochondria to modulate ATP synthesis and ROS production. Given that mitochondrial function depends on redox reactions, it is important to consider how redox signals modulate mitochondrial processes. Here, we provide the first comprehensive review on how redox signals mediated through cysteine oxidation, namely S-oxidation (sulfenylation, sulfinylation), S-glutathionylation, and S-nitrosylation, regulate key mitochondrial functions including nutrient oxidation, oxidative phosphorylation, ROS production, mitochondrial permeability transition (MPT), apoptosis, and mitochondrial fission and fusion. We also consider the chemistry behind these reactions and how they are modulated in mitochondria. In addition, we also discuss emerging knowledge on disorders and disease states that are associated with deregulated redox signaling in mitochondria and how mitochondria-targeted medicines can be utilized to restore mitochondrial redox signaling.
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Affiliation(s)
- Ryan J. Mailloux
- Institute of Biochemistry, Carleton University, 1125 Colonel By Drive, Ottawa, Ontario, Canada K1S 5B6
- Toxicology Research Division, Food Directorate, HPFB, Health Canada, Ottawa, Ontario, Canada K1A 0K9
| | - Xiaolei Jin
- Toxicology Research Division, Food Directorate, HPFB, Health Canada, Ottawa, Ontario, Canada K1A 0K9
| | - William G. Willmore
- Institute of Biochemistry, Carleton University, 1125 Colonel By Drive, Ottawa, Ontario, Canada K1S 5B6
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Nonalcoholic fatty liver disease: molecular pathways and therapeutic strategies. Lipids Health Dis 2013; 12:171. [PMID: 24209497 PMCID: PMC3827997 DOI: 10.1186/1476-511x-12-171] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2013] [Accepted: 11/07/2013] [Indexed: 02/07/2023] Open
Abstract
Along with rising numbers of patients with metabolic syndrome, the prevalence of nonalcoholic fatty liver disease (NAFLD) has increased in proportion with the obesity epidemic. While there are no established treatments for NAFLD, current research is targeting new molecular mechanisms that underlie NAFLD and associated metabolic disorders. This review discusses some of these emerging molecular mechanisms and their therapeutic implications for the treatment of NAFLD. The basic research that has identified potential molecular targets for pharmacotherapy will be outlined.
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29
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Catabolism of amino acids in livers from cafeteria-fed rats. Mol Cell Biochem 2012; 373:265-77. [PMID: 23117227 DOI: 10.1007/s11010-012-1499-0] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2012] [Accepted: 10/25/2012] [Indexed: 12/16/2022]
Abstract
Most studies using a hypercaloric diet to induce obesity have focused on the metabolism of fat and carbohydrates. Less concern has been given to the metabolism of amino acids, despite evidence of modifications in nitrogen metabolism during obesity. The aim of this study was to evaluate amino acid metabolism in livers from cafeteria diet-induced obese rats. Blood parameters were analysed, and histological sections of livers were stained with Sudan III. The enzymatic activities of some enzymes were determined in liver homogenates. Gluconeogenesis, ureagenesis, and oxygen consumption were evaluated in rat livers perfused with glutamine, alanine, or ammonium chloride. Compared to control rats, cafeteria-fed rats demonstrated higher levels of triacylglycerol and glucose in the blood and greater accumulation of fat in livers. Gluconeogenesis and urea production in livers perfused with glutamine and alanine at higher concentrations showed a substantial reduction in cafeteria-fed rats. However, no significant difference was observed among groups perfused with ammonium chloride. The activities of the enzymes alanine aminotransferase, glutaminase, and aspartate aminotransferase in the livers were reduced in cafeteria-fed rats. Taken together, these data are consistent with the hypothesis that livers from cafeteria diet-induced obese rats exhibit a limitation in their maximal capacity to metabolise glutamine and alanine to glucose, ammonia, and urea, not because of an impairment in gluconeogenesis and/or ureagenesis, but rather due to a depression in the activities of enzymes that catalyse the initial steps of amino acid metabolism.
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