1
|
Tedesco L, Corsetti G, Ruocco C, Ragni M, Rossi F, Carruba MO, Valerio A, Nisoli E. A specific amino acid formula prevents alcoholic liver disease in rodents. Am J Physiol Gastrointest Liver Physiol 2018; 314:G566-G582. [PMID: 29368944 DOI: 10.1152/ajpgi.00231.2017] [Citation(s) in RCA: 25] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Chronic alcohol consumption promotes mitochondrial dysfunction, oxidative stress, defective protein metabolism, and fat accumulation in hepatocytes (liver steatosis). Inadequate amino acid metabolism is worsened by protein malnutrition, frequently present in alcohol-consuming patients, with reduced circulating branched-chain amino acids (BCAAs). Here we asked whether dietary supplementation with a specific amino acid mixture, enriched in BCAAs (BCAAem) and able to promote mitochondrial function in muscle of middle-aged rodents, would prevent mitochondrial dysfunction and liver steatosis in Wistar rats fed on a Lieber-DeCarli ethanol (EtOH)-containing liquid diet. Supplementation of BCAAem, unlike a mixture based on the amino acid profile of casein, abrogated the EtOH-induced fat accumulation, mitochondrial impairment, and oxidative stress in liver. These effects of BCAAem were accompanied by normalization of leucine, arginine, and tryptophan levels, which were reduced in liver of EtOH-consuming rats. Moreover, although the EtOH exposure of HepG2 cells reduced mitochondrial DNA, mitochondrial transcription factors, and respiratory chain proteins, the BCAAem but not casein-derived amino acid supplementation halted this mitochondrial toxicity. Nicotinamide adenine dinucleotide levels and sirtuin 1 (Sirt1) expression, as well as endothelial nitric oxide (eNOS) and mammalian/mechanistic target of rapamycin (mTOR) signaling pathways, were downregulated in the EtOH-exposed HepG2 cells. BCAAem reverted these molecular defects and the mitochondrial dysfunction, suggesting that the mitochondrial integrity obtained with the amino acid supplementation could be mediated through a Sirt1-eNOS-mTOR pathway. Thus a dietary activation of the mitochondrial biogenesis and function by a specific amino acid supplement protects against the EtOH toxicity and preserves the liver integrity in mammals. NEW & NOTEWORTHY Dietary supplementation of a specific amino acid formula prevents both fat accumulation and mitochondrial dysfunction in hepatocytes of alcohol-consuming rats. These effects are accompanied also by increased expression of anti-reactive oxygen species genes. The amino acid-protective effects likely reflect activation of sirtuin 1-endothelial nitric oxide synthase-mammalian target of rapamycin pathway able to regulate the cellular energy balance of hepatocytes exposed to chronic, alcoholic damage.
Collapse
Affiliation(s)
- Laura Tedesco
- Department of Medical Biotechnology and Translational Medicine, Center for Study and Research on Obesity, University of Milan , Milan , Italy
| | - Giovanni Corsetti
- Department of Clinical and Experimental Sciences, University of Brescia , Brescia , Italy
| | - Chiara Ruocco
- Department of Medical Biotechnology and Translational Medicine, Center for Study and Research on Obesity, University of Milan , Milan , Italy
| | - Maurizio Ragni
- Department of Medical Biotechnology and Translational Medicine, Center for Study and Research on Obesity, University of Milan , Milan , Italy
| | - Fabio Rossi
- Department of Medical Biotechnology and Translational Medicine, Center for Study and Research on Obesity, University of Milan , Milan , Italy
| | - Michele O Carruba
- Department of Medical Biotechnology and Translational Medicine, Center for Study and Research on Obesity, University of Milan , Milan , Italy
| | - Alessandra Valerio
- Department of Molecular and Translational Medicine, University of Brescia , Brescia , Italy
| | - Enzo Nisoli
- Department of Medical Biotechnology and Translational Medicine, Center for Study and Research on Obesity, University of Milan , Milan , Italy
| |
Collapse
|
2
|
Glutamate contributes to alcohol hepatotoxicity by enhancing oxidative stress in mitochondria. J Bioenerg Biomembr 2017; 49:253-264. [PMID: 28478591 DOI: 10.1007/s10863-017-9713-0] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2017] [Accepted: 04/24/2017] [Indexed: 02/07/2023]
Abstract
Chronic alcohol intoxication is associated with increased oxidative stress. However, the mechanisms by which ethanol triggers an increase in the production of reactive oxygen species (ROS) and the role of mitochondria in the development of oxidative stress has been insufficiently studied. The biochemical and proteomic data obtained in the present work suggest that one of the main causes of an increase in ROS generation is enhanced oxidation of glutamate in response to long-term alcohol exposure. In the course of glutamate oxidation, liver mitochondria from alcoholic rats generated more superoxide anion and H2O2 than in the presence of other substrates and more than control organelles. In mitochondria from alcoholic rats, rates of H2O2 production and NAD reduction in the presence of glutamate were almost twice higher than in the control. The proteomic study revealed a higher content of glutamate dehydrogenase in liver mitochondria of rats subjected to chronic alcohol exposure. Simultaneously, the content of mitochondrial catalase decreased compared to control. Each of these factors stimulates the production of ROS in addition to ROS generated by the respiratory chain complex I. The results are consistent with the conclusion that glutamate contributes to alcohol hepatotoxicity by enhancing oxidative stress in mitochondria.
Collapse
|
3
|
Sun Q, Zhong W, Zhang W, Zhou Z. Defect of mitochondrial respiratory chain is a mechanism of ROS overproduction in a rat model of alcoholic liver disease: role of zinc deficiency. Am J Physiol Gastrointest Liver Physiol 2016; 310:G205-14. [PMID: 26585415 PMCID: PMC4971814 DOI: 10.1152/ajpgi.00270.2015] [Citation(s) in RCA: 71] [Impact Index Per Article: 8.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/11/2015] [Accepted: 11/14/2015] [Indexed: 02/06/2023]
Abstract
Morphological and functional alterations of hepatic mitochondria have been documented in patients with alcoholic liver disease (ALD). Our recent study demonstrated that zinc level was decreased in whole liver and mitochondria by chronic alcohol feeding. The present study was undertaken to determine whether zinc deficiency mediates alcohol-induced mitochondrial electron transport chain (ETC) defect and whether defective ETC function may lead to generation of reactive oxygen species (ROS). Male Wistar rats were pair fed with the Lieber-DeCarli control or ethanol diet for 5 mo. Chronic alcohol exposure increased hepatic triglyceride, free fatty acid, and 4-hydroxynonenal (4HNE) levels; meanwhile hepatic mitochondrial 4HNE level was also increased. Moreover, hepatic mitochondrial respiratory complexes I, III, IV, and V and hepatic ATP production were decreased by chronic alcohol exposure. Chronic alcohol feeding decreased peroxisome proliferator-activated receptor gamma coactivator-1-alpha (PGC1α), nuclear respiratory factor 1 (NRF1), mitochondrial transcription factor A (TFAM), and mitochondrial DNA. HepG2 cells were treated with N,N,N',N'-tetrakis (2-pyridylmethyl) ethylenediamine (TPEN) for 6 h. Zinc deficiency significantly decreased mitochondrial respiratory complexes I, III, and IV. In addition, PGC1α, NRF1, and TFAM levels as well as mitochondrial DNA were significantly decreased by TPEN treatment. Knockdown of mitochondrial respiratory complexes I, III, or IV by shRNA caused a decrease in mitochondrial membrane potential and an increase in ROS production. These results suggest that alcohol-induced hepatic zinc deficiency could inactivate mitochondrial biogenesis pathway and decrease mitochondrial DNA replication, which, in turn, decreases mitochondrial complex protein expression. The defect of mitochondrial respiratory complexes may worsen alcohol-induced ROS production.
Collapse
Affiliation(s)
- Qian Sun
- Department of Nutrition, University of North Carolina at Greensboro, North Carolina Research Campus, Kannapolis, North Carolina; and Center for Translational Biomedical Research, University of North Carolina at Greensboro, North Carolina Research Campus, Kannapolis, North Carolina
| | - Wei Zhong
- Center for Translational Biomedical Research, University of North Carolina at Greensboro, North Carolina Research Campus, Kannapolis, North Carolina
| | - Wenliang Zhang
- Center for Translational Biomedical Research, University of North Carolina at Greensboro, North Carolina Research Campus, Kannapolis, North Carolina
| | - Zhanxiang Zhou
- Department of Nutrition, University of North Carolina at Greensboro, North Carolina Research Campus, Kannapolis, North Carolina; and Center for Translational Biomedical Research, University of North Carolina at Greensboro, North Carolina Research Campus, Kannapolis, North Carolina
| |
Collapse
|
4
|
Zheng G, Lyu J, Liu S, Huang J, Liu C, Xiang D, Xie M, Zeng Q. Silencing of uncoupling protein 2 by small interfering RNA aggravates mitochondrial dysfunction in cardiomyocytes under septic conditions. Int J Mol Med 2015; 35:1525-36. [PMID: 25873251 PMCID: PMC4432931 DOI: 10.3892/ijmm.2015.2177] [Citation(s) in RCA: 36] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2014] [Accepted: 04/02/2015] [Indexed: 01/22/2023] Open
Abstract
Uncoupling protein 2 (UCP2) regulates the production of mitochondrial reactive oxygen species (ROS) and cellular energy transduction under physiological or pathological conditions. In this study, we aimed to determine whether mitochondrial UCP2 plays a protective role in cardiomyocytes under septic conditions. In order to mimic the septic condition, rat embryonic cardiomyoblast-derived H9C2 cells were cultured in the presence of lipopolysaccharide (LPS) plus peptidoglycan G (PepG) and small interfering RNA (siRNA) against UCP2 (siUCP2) was used to suppress UCP2 expression. Reverse transcription quantitative-polymerase chain reaction (RT-qPCR), western blot analysis, transmission electron microscopy (TEM), confocal microscopy and flow cytometry (FCM) were used to detect the mRNA levels, protein levels, mitochondrial morphology and mitochondrial membrane potential (MMP or ΔΨm) in qualitative and quantitative analyses, respectively. Indicators of cell damage [lactate dehydrogenase (LDH), creatine kinase (CK), interleukin (IL)-6 and tumor necrosis factor (TNF)-α in the culture supernatant] and mitochondrial function [ROS, adenosine triphosphate (ATP) and mitochondrial DNA (mtDNA)] were detected. Sepsis enhanced the mRNA and protein expression of UCP2 in the H9C2 cells, damaged the mitochondrial ultrastructure, increased the forward scatter (FSC)/side scatter (SSC) ratio, increased the CK, LDH, TNF-α and IL-6 levels, and lead to the dissipation of MMP, as well as the overproduction of ROS; in addition, the induction of sepsis led to a decrease in ATP levels and the deletion of mtDNA. The silencing of UCP2 aggravated H9C2 cell damage and mitochondrial dysfunction. In conclusion, our data demonstrate that mitochondrial morphology and funtion are damaged in cardiomyocytes under septic conditions, while the silencing of UCP2 using siRNA aggravated this process, indicating that UCP2 may play a protective role in cardiomyocytes under septic conditions.
Collapse
Affiliation(s)
- Guilang Zheng
- Department of Pediatrics, Zhujiang Hospital, Southern Medical University, Guangzhou, Guangdong 510282, P.R. China
| | - Juanjuan Lyu
- Department of Pediatrics, Zhujiang Hospital, Southern Medical University, Guangzhou, Guangdong 510282, P.R. China
| | - Shu Liu
- Department of Pediatrics, Zhujiang Hospital, Southern Medical University, Guangzhou, Guangdong 510282, P.R. China
| | - Jinda Huang
- Department of Pediatrics, Zhujiang Hospital, Southern Medical University, Guangzhou, Guangdong 510282, P.R. China
| | - Cui Liu
- Department of Pediatrics, Zhujiang Hospital, Southern Medical University, Guangzhou, Guangdong 510282, P.R. China
| | - Dan Xiang
- Department of Pediatrics, Zhujiang Hospital, Southern Medical University, Guangzhou, Guangdong 510282, P.R. China
| | - Meiyan Xie
- Department of Pediatrics, Zhujiang Hospital, Southern Medical University, Guangzhou, Guangdong 510282, P.R. China
| | - Qiyi Zeng
- Department of Pediatrics, Zhujiang Hospital, Southern Medical University, Guangzhou, Guangdong 510282, P.R. China
| |
Collapse
|
5
|
Dosumu O, Osinubi A, Duru F. Alcohol induced testicular damage: Can abstinence equal recovery? MIDDLE EAST FERTILITY SOCIETY JOURNAL 2014. [DOI: 10.1016/j.mefs.2014.01.003] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023] Open
|
6
|
Galicia-Moreno M, Gutiérrez-Reyes G. Papel del estrés oxidativo en el desarrollo de la enfermedad hepática alcohólica. REVISTA DE GASTROENTEROLOGÍA DE MÉXICO 2014; 79:135-44. [DOI: 10.1016/j.rgmx.2014.03.001] [Citation(s) in RCA: 56] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/13/2013] [Revised: 03/19/2014] [Accepted: 03/26/2014] [Indexed: 12/23/2022]
|
7
|
Galicia-Moreno M, Gutiérrez-Reyes G. The role of oxidative stress in the development of alcoholic liver disease. REVISTA DE GASTROENTEROLOGÍA DE MÉXICO 2014. [DOI: 10.1016/j.rgmxen.2014.06.007] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
|
8
|
Sid B, Verrax J, Calderon PB. Role of oxidative stress in the pathogenesis of alcohol-induced liver disease. Free Radic Res 2013; 47:894-904. [PMID: 23800214 DOI: 10.3109/10715762.2013.819428] [Citation(s) in RCA: 70] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
Chronic alcohol consumption is a well-known risk factor for liver disease, which represents a major cause of morbidity and mortality worldwide. The pathological process of alcohol-induced liver disease is characterized by a broad spectrum of morphological changes ranging from steatosis with minimal injury to more advanced liver damage, including steato-hepatitis and fibrosis/cirrhosis. Experimental and clinical studies increasingly show that the oxidative damage induced by ethanol contribute in many ways to the pathogenesis of alcohol hepatotoxicity. This article describes the contribution of oxidative mechanisms to liver damage by alcohol.
Collapse
Affiliation(s)
- B Sid
- Université Catholique de Louvain, Louvain Drug Research Institute, Toxicology and Cancer Biology Research Group (GTOX) , Brussels , Belgium
| | | | | |
Collapse
|
9
|
Mitochondrial roles and cytoprotection in chronic liver injury. Biochem Res Int 2012; 2012:387626. [PMID: 22745910 PMCID: PMC3382253 DOI: 10.1155/2012/387626] [Citation(s) in RCA: 102] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2012] [Revised: 03/20/2012] [Accepted: 04/11/2012] [Indexed: 02/06/2023] Open
Abstract
The liver is one of the richest organs in terms of number and density of mitochondria. Most chronic liver diseases are associated with the accumulation of damaged mitochondria. Hepatic mitochondria have unique features compared to other organs' mitochondria, since they are the hub that integrates hepatic metabolism of carbohydrates, lipids and proteins. Mitochondria are also essential in hepatocyte survival as mediator of apoptosis and necrosis. Hepatocytes have developed different mechanisms to keep mitochondrial integrity or to prevent the effects of mitochondrial lesions, in particular regulating organelle biogenesis and degradation. In this paper, we will focus on the role of mitochondria in liver physiology, such as hepatic metabolism, reactive oxygen species homeostasis and cell survival. We will also focus on chronic liver pathologies, especially those linked to alcohol, virus, drugs or metabolic syndrome and we will discuss how mitochondria could provide a promising therapeutic target in these contexts.
Collapse
|
10
|
Guimarães EL, Best J, Dollé L, Najimi M, Sokal E, van Grunsven LA. Mitochondrial uncouplers inhibit hepatic stellate cell activation. BMC Gastroenterol 2012; 12:68. [PMID: 22686625 PMCID: PMC3439697 DOI: 10.1186/1471-230x-12-68] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/06/2012] [Accepted: 04/23/2012] [Indexed: 12/30/2022] Open
Abstract
Background Mitochondrial dysfunction participates in the progression of several pathologies. Although there is increasing evidence for a mitochondrial role in liver disease, little is known about its contribution to hepatic stellate cell (HSC) activation. In this study we investigated the role of mitochondrial activity through mild uncoupling during in vitro activation of HSCs. Methods Cultured primary human and mouse HSCs were treated with the chemical uncouplers FCCP and Valinomycin. ATP levels were measured by luciferase assay and production of reactive oxygen species was determined using the fluorescent probe DCFH-DA. Possible cytotoxicity by uncoupler treatment was evaluated by caspase 3/7 activity and cytoplasmic protease leakage. Activation of HSCs and their response to the pro-fibrogenic cytokine TGF-β was evaluated by gene expression of activation markers and signal mediators using RT-qPCR. Proliferation was measured by incorporation of EdU and protein expression of α-smooth muscle actin was analyzed by immunocytochemistry and western blot. Results FCCP and Valinomycin treatment mildly decreased ATP and reactive oxygen species levels. Both uncouplers increased the expression of mitochondrial genes such as Tfam and COXIV while inducing morphological features of quiescent mouse HSCs and abrogating TGF-β signal transduction. Mild uncoupling reduced HSC proliferation and expression of pro-fibrogenic markers of mouse and human HSCs. Conclusions Mild mitochondrial uncoupling inhibits culture-induced HSC activation and their response to pro-fibrogenic cytokines like TGF-β. These results therefore suggest mitochondrial uncoupling of HSCs as a strategy to reduce progression of liver fibrosis.
Collapse
Affiliation(s)
- Eduardo L Guimarães
- Department of Cell Biology, Liver Cell Biology Lab, Vrije Universiteit Brussel, Laarbeeklaan 103, Brussels 1090, Belgium
| | | | | | | | | | | |
Collapse
|
11
|
Bansal S, Srinivasan S, Anandasadagopan S, Chowdhury AR, Selvaraj V, Kalyanaraman B, Joseph J, Avadhani NG. Additive effects of mitochondrion-targeted cytochrome CYP2E1 and alcohol toxicity on cytochrome c oxidase function and stability of respirosome complexes. J Biol Chem 2012; 287:15284-97. [PMID: 22396533 DOI: 10.1074/jbc.m111.314062] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023] Open
Abstract
Alcohol treatment induces oxidative stress by a combination of increased production of partially reduced oxygen species and decreased cellular antioxidant pool, including GSH. Recently, we showed that mitochondrion-targeted CYP2E1 augments alcohol-mediated toxicity, causing an increase in reactive oxygen species production and oxidative stress. Here, we show that cytochrome c oxidase (CcO), the terminal oxidase of the mitochondrial respiratory chain, is a critical target of CYP2E1-mediated alcohol toxicity. COS-7 and Hep G2 cell lines expressing predominantly mitochondrion-targeted (Mt(++)) CYP2E1 and livers from alcohol-treated rats showed loss of CcO activity and increased protein carbonylation, which was accompanied by a decline in the steady state levels of subunits I, IVI1, and Vb of the CcO complex. This was also accompanied by reduced mitochondrial DNA content and reduced mitochondrial mRNA. These changes were more prominent in Mt(++) cells in comparison with wild type (WT) CYP2E1-expressing or ER(+) (mostly microsome-targeted) cells. In addition, mitochondrion-specific antioxidants, ubiquinol conjugated to triphenyl phosphonium, triphenylphosphonium conjugated carboxyl proxyl, and the CYP2E1 inhibitor diallyl sulfide prevented the loss of CcO activity and the CcO subunits, most likely through reduced oxidative damage to the enzyme complex. Our results suggest that damage to CcO and dissociation of respirosome complexes are critical factors in alcohol-induced toxicity, which is augmented by mitochondrion-targeted CYP2E1. We propose that CcO is one of the direct and immediate targets of alcohol-induced toxicity causing respiratory dysfunction.
Collapse
Affiliation(s)
- Seema Bansal
- Department of Animal Biology and the Mari Lowe Center for Comparative Oncology, School of Veterinary Medicine, University of Pennsylvania, Philadelphia, Pennsylvania 19104, USA
| | | | | | | | | | | | | | | |
Collapse
|
12
|
Choumar A, Tarhuni A, Lettéron P, Reyl-Desmars F, Dauhoo N, Damasse J, Vadrot N, Nahon P, Moreau R, Pessayre D, Mansouri A. Lipopolysaccharide-induced mitochondrial DNA depletion. Antioxid Redox Signal 2011; 15:2837-54. [PMID: 21767162 DOI: 10.1089/ars.2010.3713] [Citation(s) in RCA: 54] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
Hepatic energy depletion has been described in severe sepsis, and lipopolysaccharide (LPS) has been shown to cause mitochondrial DNA (mtDNA) damage. To clarify the mechanisms of LPS-induced mtDNA damage and mitochondrial alterations, we treated wild-type (WT) or transgenic manganese superoxide dismutase-overerexpressing (MnSOD(+++)) mice with a single dose of LPS (5 mg/kg). In WT mice, LPS increased mitochondrial reactive oxygen species formation, hepatic inducible nitric oxide synthase (NOS) mRNA and protein, tumor necrosis factor-alpha, interleukin-1 beta, and high-mobility group protein B1 concentrations. Six to 48 h after LPS administration (5 mg/kg), liver mtDNA levels, respiratory complex I activity, and adenosine triphosphate (ATP) contents were decreased. In addition, LPS increased interferon-β concentration and decreased mitochondrial transcription factor A (Tfam) mRNA, Tfam protein, and mtDNA-encoded mRNAs. Morphological studies showed mild hepatic inflammation. The LPS (5 mg/kg)-induced mtDNA depletion, complex I inactivation, ATP depletion, and alanine aminotransferase increase were prevented in MnSOD(+++) mice or in WT mice cotreated with 1400W (a NOS inhibitor), (2-(2,2,6,6-tetramethylpiperidin-1-oxyl-4-ylamino)-2-oxoethyl)triphenylphosphonium chloride, monohydrate (a superoxide scavenger) or uric acid (a peroxynitrite scavenger). The MnSOD overexpression delayed death in mice challenged by a higher, lethal dose of LPS (25 mg/kg). In conclusion, LPS administration damages mtDNA and alters mitochondrial function. The protective effects of MnSOD, NOS inhibitors, and superoxide or peroxynitrite scavengers point out a role of the superoxide anion reacting with NO to form mtDNA- and protein-damaging peroxynitrite. In addition to the acute damage caused by reactive species, decreased levels of mitochondrial transcripts contribute to mitochondrial dysfunction.
Collapse
Affiliation(s)
- Amal Choumar
- INSERM, U773, Centre de Recherche Biomédicale Bichat Beaujon CRB3, Paris, France
| | | | | | | | | | | | | | | | | | | | | |
Collapse
|
13
|
King AL, Swain TM, Dickinson DA, Lesort MJ, Bailey SM. Chronic ethanol consumption enhances sensitivity to Ca(2+)-mediated opening of the mitochondrial permeability transition pore and increases cyclophilin D in liver. Am J Physiol Gastrointest Liver Physiol 2010; 299:G954-66. [PMID: 20651005 PMCID: PMC2957342 DOI: 10.1152/ajpgi.00246.2010] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/26/2010] [Accepted: 07/19/2010] [Indexed: 01/31/2023]
Abstract
Chronic ethanol consumption increases mitochondrial oxidative stress and sensitivity to form the mitochondrial permeability transition pore (MPTP). The mechanism responsible for increased MPTP sensitivity in ethanol-exposed mitochondria and its relation to mitochondrial Ca(2+) handling is unknown. Herein, we investigated whether increased sensitivity to MPTP induction in liver mitochondria from ethanol-fed rats compared with controls is related to an ethanol-dependent change in mitochondrial Ca(2+) accumulation. Liver mitochondria were isolated from control and ethanol-fed rats, and Ca(2+)-mediated induction of the MPTP and mitochondrial Ca(2+) retention capacity were measured. Levels of proposed MPTP proteins as well as select pro- and antiapoptotic proteins were measured along with gene expression. We observed increased steatosis and TUNEL-stained nuclei in liver of ethanol-fed rats compared with controls. Liver mitochondria from ethanol-fed rats had increased levels of proapoptotic Bax protein and reduced Ca(2+) retention capacity compared with control mitochondria. We observed increased cyclophilin D (Cyp D) gene expression in liver and protein in mitochondria from ethanol-fed animals compared with controls, whereas there was no change in the adenine nucleotide translocase and voltage-dependent anion channel. Together, these results suggest that enhanced sensitivity to Ca(2+)-mediated MPTP induction may be due, in part, to higher Cyp D levels in liver mitochondria from ethanol-fed rats. Therefore, therapeutic strategies aimed at normalizing Cyp D levels may be beneficial in preventing ethanol-dependent mitochondrial dysfunction and liver injury.
Collapse
Affiliation(s)
- Adrienne L King
- Dept. of Environmental Health Sciences, Center for Free Radical Biology, Univ. of Alabama at Birmingham, AL 35294, USA
| | | | | | | | | |
Collapse
|
14
|
Andringa KK, King AL, Eccleston HB, Mantena SK, Landar A, Jhala NC, Dickinson DA, Squadrito GL, Bailey SM. Analysis of the liver mitochondrial proteome in response to ethanol and S-adenosylmethionine treatments: novel molecular targets of disease and hepatoprotection. Am J Physiol Gastrointest Liver Physiol 2010; 298:G732-45. [PMID: 20150243 PMCID: PMC2867419 DOI: 10.1152/ajpgi.00332.2009] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/10/2009] [Accepted: 02/08/2010] [Indexed: 01/31/2023]
Abstract
S-adenosylmethionine (SAM) minimizes alcohol hepatotoxicity; however, the molecular mechanisms responsible for SAM hepatoprotection remain unknown. Herein, we use proteomics to determine whether the hepatoprotective action of SAM against early-stage alcoholic liver disease is linked to alterations in the mitochondrial proteome. For this, male rats were fed control or ethanol-containing liquid diets +/- SAM and liver mitochondria were prepared for proteomic analysis. Two-dimensional isoelectric focusing (2D IEF/SDS-PAGE) and blue native gel electrophoresis (BN-PAGE) were used to determine changes in matrix and oxidative phosphorylation (OxPhos) proteins, respectively. SAM coadministration minimized alcohol-dependent inflammation and preserved mitochondrial respiration. SAM supplementation preserved liver SAM levels in ethanol-fed rats; however, mitochondrial SAM levels were increased by ethanol and SAM treatments. With use of 2D IEF/SDS-PAGE, 30 proteins showed significant changes in abundance in response to ethanol, SAM, or both. Classes of proteins affected by ethanol and SAM treatments were chaperones, beta oxidation proteins, sulfur metabolism proteins, and dehydrogenase enzymes involved in methionine, glycine, and choline metabolism. BN-PAGE revealed novel changes in the levels of 19 OxPhos proteins in response to ethanol, SAM, or both. Ethanol- and SAM-dependent alterations in the proteome were not linked to corresponding changes in gene expression. In conclusion, ethanol and SAM treatment led to multiple changes in the liver mitochondrial proteome. The protective effects of SAM against alcohol toxicity are mediated, in part, through maintenance of proteins involved in key mitochondrial energy conserving and biosynthetic pathways. This study demonstrates that SAM may be a promising candidate for treatment of alcoholic liver disease.
Collapse
Affiliation(s)
- Kelly K Andringa
- Dept. of Environmental Health Sciences, Univ. of Alabama at Birmingham, 35294, USA
| | | | | | | | | | | | | | | | | |
Collapse
|
15
|
Larosche I, Lettéron P, Berson A, Fromenty B, Huang TT, Moreau R, Pessayre D, Mansouri A. Hepatic mitochondrial DNA depletion after an alcohol binge in mice: probable role of peroxynitrite and modulation by manganese superoxide dismutase. J Pharmacol Exp Ther 2009; 332:886-97. [PMID: 20016022 DOI: 10.1124/jpet.109.160879] [Citation(s) in RCA: 51] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023] Open
Abstract
Alcohol consumption increases reactive oxygen species (ROS) formation, which can damage mitochondrial DNA (mtDNA) and alter mitochondrial function. To test whether manganese superoxide dismutase (MnSOD) modulates acute alcohol-induced mitochondrial alterations, transgenic MnSOD-overexpressing (MnSOD(+++)) mice, heterozygous knockout (MnSOD(+/-)) mice, and wild-type (WT) littermates were sacrificed 2 or 24 h after intragastric ethanol administration (5 g/kg). Alcohol administration further increased MnSOD activity in MnSOD(+++) mice, but further decreased it in MnSOD(+/-) mice. In WT mice, alcohol administration transiently increased mitochondrial ROS formation, decreased mitochondrial glutathione, depleted and damaged mtDNA, and decreased complex I and V activities; alcohol durably increased inducible nitric-oxide synthase (NOS) expression, plasma nitrites/nitrates, and the nitration of tyrosine residues in complex V proteins. These effects were prevented in MnSOD(+++) mice and prolonged in MnSOD(+/-) mice. In alcoholized WT or MnSOD(+/-) mice, mtDNA depletion and the nitration of tyrosine residues in complex I and V proteins were prevented or attenuated by cotreatment with tempol (4-hydroxy-2,2,6,6-tetramethylpiperidine-N-oxyl), a superoxide scavenger; N(omega)-nitro-l-arginine methyl ester and N-[3-(aminomethyl)benzyl]acetamidine (1,400W), two NOS inhibitors; or uric acid, a peroxynitrite scavenger. In conclusion, MnSOD overexpression prevents, and MnSOD deficiency prolongs, mtDNA depletion after an acute alcohol binge in mice. The protective effects of MnSOD, tempol, NOS inhibitors, and uric acid point out a role of the superoxide anion reacting with NO to form mtDNA-damaging peroxynitrite.
Collapse
Affiliation(s)
- Isabelle Larosche
- Institut National de la Santé et de la Recherche Médicale U773, Faculté de Médecine Xavier Bichat, 16 rue Henri Huchard, BP 416, 75018 Paris, France
| | | | | | | | | | | | | | | |
Collapse
|
16
|
Prolonged ethanol administration depletes mitochondrial DNA in MnSOD-overexpressing transgenic mice, but not in their wild type littermates. Toxicol Appl Pharmacol 2009; 234:326-38. [DOI: 10.1016/j.taap.2008.11.004] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2008] [Revised: 10/15/2008] [Accepted: 11/04/2008] [Indexed: 02/05/2023]
|
17
|
Scaloni A, Codarin E, Di Maso V, Arena S, Renzone G, Tiribelli C, Quadrifoglio F, Tell G. Modern strategies to identify new molecular targets for the treatment of liver diseases: The promising role of Proteomics and Redox Proteomics investigations. Proteomics Clin Appl 2009; 3:242-62. [DOI: 10.1002/prca.200800169] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2008] [Indexed: 12/16/2022]
|
18
|
Sykora P, Kharbanda KK, Crumm SE, Cahill A. S-adenosyl-L-methionine co-administration prevents the ethanol-elicited dissociation of hepatic mitochondrial ribosomes in male rats. Alcohol Clin Exp Res 2008; 33:1-9. [PMID: 18828798 DOI: 10.1111/j.1530-0277.2008.00803.x] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
BACKGROUND Chronic ethanol feeding to male rats has been shown to result in decreased mitochondrial translation, depressed respiratory complex levels and mitochondrial respiration rates. In addition, ethanol consumption has been shown to result in an increased dissociation of mitoribosomes. S-adenosyl-L-methionine (SAM) is required for the assembly and subsequent stability of mitoribosomes and is depleted during chronic ethanol feeding. The ability of dietary SAM co-administration to prevent these ethanol-elicited lesions was investigated. METHODS Male Sprague-Dawley rats were fed a nutritionally adequate liquid diet with ethanol comprising 36% of the calories according to a pair-fed design for 28 days. For some animals, SAM was supplemented in the diet at 200 mg/l. Liver mitochondria were prepared and mitoribosomes isolated. Respiration rates, ATP levels, respiratory complex levels, and the extent of mitoribosome dissociation were determined. RESULTS Twenty-eight days of ethanol feeding were found to result in decreased SAM content, depressed respiration, and increased mitoribosome dissociation. No changes in mitochondrial protein content; levels of respiratory complexes I, III, and V; complex I activities; and ATP levels were detected. Co-administration of SAM in the diet was found to prevent ethanol-induced SAM depletion, respiration decreases and mitoribosome dissociation. CONCLUSIONS Taken together, these findings suggest (1) that mitoribosome dissociation precedes respiratory complex depressions in alcoholic animals and (2) that dietary supplementation of SAM prevents some of the early mitochondrial lesions associated with chronic ethanol consumption.
Collapse
Affiliation(s)
- Peter Sykora
- Department of Pathology, Anatomy and Cell Biology, Thomas Jefferson University, Philadelphia, PA 19107, USA
| | | | | | | |
Collapse
|
19
|
Cahill A, Sykora P. Alcoholic liver disease and the mitochondrial ribosome: methods of analysis. Methods Mol Biol 2008; 447:381-94. [PMID: 18369931 DOI: 10.1007/978-1-59745-242-7_25] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
Chronic alcohol consumption has been shown to severely compromise mitochondrial protein synthesis. Hepatic mitochondria isolated from alcoholic animals contain decreased levels of respiratory complexes and display depressed respiration rates when compared to pair-fed controls. One underlying mechanism for this involves ethanol-elicited alterations in the structural and functional integrity of the mitochondrial ribosome. Ethanol feeding results in ribosomal changes that include decreased sedimentation rates, larger hydrodynamic volumes, increased levels of unassociated subunits and changes in the levels of specific ribosomal proteins. The methods presented in this chapter detail how to isolate mitochondrial ribosomes, determine ribosomal activity, separate ribosomes into nucleic acid and protein, and perform two-dimensional nonequilibrium pH gradient electrophoretic polyacrylamide gel electrophoresis to separate and subsequently identify mitochondrial ribosomal proteins.
Collapse
Affiliation(s)
- Alan Cahill
- Department of Pathology, Anatomy and Cell Biology, Thomas Jefferson University, Philadelphia, PA, USA
| | | |
Collapse
|
20
|
Proteomic approaches to identify and characterize alterations to the mitochondrial proteome in alcoholic liver disease. Methods Mol Biol 2008; 447:369-80. [PMID: 18369930 DOI: 10.1007/978-1-59745-242-7_24] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
Abstract
Mitochondrial dysfunction is recognized as a contributing factor to a number of diseases, including chronic alcohol-induced hepatotoxicity. Although there is a detailed understanding of the metabolic pathways and proteins of the liver mitochondrion, little is known of how changes in the mitochondrial proteome contribute to the development of hepatic pathologies. In this short overview the insights gained from study of changes in the mitochondrial proteome in alcoholic liver disease will be described. Profiling the liver mitochondrial proteome has the potential to shed light on the alcohol-mediated molecular defects responsible for mitochondrial and cellular dysfunction. The methods presented herein demonstrate the power of using complementary proteomics approaches, that is, 2-D IEF/SDS-PAGE and BN-PAGE, to identify changes in the abundance of mitochondrial proteins after chronic alcohol consumption. These proteomic data can then be integrated into a logical and mechanistic framework to further our understanding of the role of mitochondrial dysfunction in the pathogenesis of alcohol-induced liver disease.
Collapse
|
21
|
Mantena SK, King AL, Andringa KK, Eccleston HB, Bailey SM. Mitochondrial dysfunction and oxidative stress in the pathogenesis of alcohol- and obesity-induced fatty liver diseases. Free Radic Biol Med 2008; 44:1259-72. [PMID: 18242193 PMCID: PMC2323912 DOI: 10.1016/j.freeradbiomed.2007.12.029] [Citation(s) in RCA: 333] [Impact Index Per Article: 20.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/18/2007] [Revised: 12/19/2007] [Accepted: 12/19/2007] [Indexed: 12/16/2022]
Abstract
Fatty liver disease associated with chronic alcohol consumption or obesity/type 2 diabetes has emerged as a serious public health problem. Steatosis, accumulation of triglyceride in hepatocytes, is now recognized as a critical "first-hit" in the pathogenesis of liver disease. It is proposed that steatosis "primes" the liver to progress to more severe liver pathologies when individuals are exposed to subsequent metabolic and/or environmental stressors or "second-hits." Genetic risk factors can also influence the susceptibility to and severity of fatty liver disease. Furthermore, oxidative stress, disrupted nitric oxide (NO) signaling, and mitochondrial dysfunction are proposed to be key molecular events that accelerate or worsen steatosis and initiate progression to steatohepatitis and fibrosis. This review article will discuss the following topics regarding the pathobiology and molecular mechanisms responsible for fatty liver disease: (1) the "two-hit" or "multi-hit" hypothesis, (2) the role of mitochondrial bioenergetic defects and oxidant stress, (3) the interplay between NO and mitochondria in fatty liver disease, (4) genetic risk factors and oxidative stress-responsive genes, and (5) the feasibility of antioxidants for treatment.
Collapse
Affiliation(s)
| | | | | | | | - Shannon M. Bailey
- *Corresponding Author: Shannon M. Bailey, PhD, Associate Professor, Department of Environmental Health Sciences, Center for Free Radical Biology, University of Alabama at Birmingham, Ryals Building, Room 623, 1530 3 Avenue South, Birmingham, AL 35294 USA, Phone: 205-934-7070, Fax: 205-975-6341,
| |
Collapse
|
22
|
Mantena SK, King AL, Andringa KK, Landar A, Darley-Usmar V, Bailey SM. Novel interactions of mitochondria and reactive oxygen/nitrogen species in alcohol mediated liver disease. World J Gastroenterol 2007; 13:4967-73. [PMID: 17854139 PMCID: PMC4434620 DOI: 10.3748/wjg.v13.i37.4967] [Citation(s) in RCA: 44] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
Mitochondrial dysfunction is known to be a contributing factor to a number of diseases including chronic alcohol induced liver injury. While there is a detailed understanding of the metabolic pathways and proteins of the liver mitochondrion, little is known regarding how changes in the mitochondrial proteome may contribute to the development of hepatic pathologies. Emerging evidence indicates that reactive oxygen and nitrogen species disrupt mitochondrial function through post-translational modifications to the mitochondrial proteome. Indeed, various new affinity labeling reagents are available to test the hypothesis that post-translational modification of proteins by reactive species contributes to mitochondrial dysfunction and alcoholic fatty liver disease. Specialized proteomic techniques are also now available, which allow for identification of defects in the assembly of multi-protein complexes in mitochondria and the resolution of the highly hydrophobic proteins of the inner membrane. In this review knowledge gained from the study of changes to the mitochondrial proteome in alcoholic hepatotoxicity will be described and placed into a mechanistic framework to increase understanding of the role of mitochondrial dysfunction in liver disease.
Collapse
Affiliation(s)
- Sudheer K Mantena
- Department of Environmental Health Sciences, Center for Free Radical Biology, University of Alabama at Birmingham, Ryals Building, Room 623, 1530 3rd Avenue South, Birmingham, AL 35294, USA
| | | | | | | | | | | |
Collapse
|
23
|
Das SK, Vasudevan DM. Alcohol-induced oxidative stress. Life Sci 2007; 81:177-87. [PMID: 17570440 DOI: 10.1016/j.lfs.2007.05.005] [Citation(s) in RCA: 571] [Impact Index Per Article: 33.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2006] [Revised: 04/26/2007] [Accepted: 05/04/2007] [Indexed: 10/23/2022]
Abstract
Alcohol-induced oxidative stress is linked to the metabolism of ethanol involving both microsomal and mitochondrial systems. Ethanol metabolism is directly involved in the production of reactive oxygen species (ROS) and reactive nitrogen species (RNS). These form an environment favourable to oxidative stress. Ethanol treatment results in the depletion of GSH levels and decreases antioxidant activity. It elevates malondialdehyde (MDA), hydroxyethyl radical (HER), and hydroxynonenal (HNE) protein adducts. These cause the modification of all biological structures and consequently result in serious malfunction of cells and tissues.
Collapse
Affiliation(s)
- Subir Kumar Das
- Department of Biochemistry, Amrita Institute of Medical Sciences, Elamakkara, Kerala, India.
| | | |
Collapse
|
24
|
Bailey SM, Robinson G, Pinner A, Chamlee L, Ulasova E, Pompilius M, Page GP, Chhieng D, Jhala N, Landar A, Kharbanda KK, Ballinger S, Darley-Usmar V. S-adenosylmethionine prevents chronic alcohol-induced mitochondrial dysfunction in the rat liver. Am J Physiol Gastrointest Liver Physiol 2006; 291:G857-67. [PMID: 16825707 DOI: 10.1152/ajpgi.00044.2006] [Citation(s) in RCA: 89] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
An early event that occurs in response to alcohol consumption is mitochondrial dysfunction, which is evident in changes to the mitochondrial proteome, respiration defects, and mitochondrial DNA (mtDNA) damage. S-adenosylmethionine (SAM) has emerged as a potential therapeutic for treating alcoholic liver disease through mechanisms that appear to involve decreases in oxidative stress and proinflammatory cytokine production as well as the alleviation of steatosis. Because mitochondria are a source of reactive oxygen/nitrogen species and a target for oxidative damage, we tested the hypothesis that SAM treatment during alcohol exposure preserves organelle function. Mitochondria were isolated from livers of rats fed control and ethanol diets with and without SAM for 5 wk. Alcohol feeding caused a significant decrease in state 3 respiration and the respiratory control ratio, whereas SAM administration prevented these alcohol-mediated defects and preserved hepatic SAM levels. SAM treatment prevented alcohol-associated increases in mitochondrial superoxide production, mtDNA damage, and inducible nitric oxide synthase induction, without a significant lessening of steatosis. Accompanying these indexes of oxidant damage, SAM prevented alcohol-mediated losses in cytochrome c oxidase subunits as shown using blue native PAGE proteomics and immunoblot analysis, which resulted in partial preservation of complex IV activity. SAM treatment attenuated the upregulation of the mitochondrial stress chaperone prohibitin. Although SAM supplementation did not alleviate steatosis by itself, SAM prevented several key alcohol-mediated defects to the mitochondria genome and proteome that contribute to the bioenergetic defect in the liver after alcohol consumption. These findings reveal new molecular targets through which SAM may work to alleviate one critical component of alcohol-induced liver injury: mitochondria dysfunction.
Collapse
Affiliation(s)
- Shannon M Bailey
- Department of Environmental Health Sciences, School of Public Health, University of Alabama, Birmingham, AL 35294, USA.
| | | | | | | | | | | | | | | | | | | | | | | | | |
Collapse
|
25
|
Cahill A, Hershman S, Davies A, Sykora P. Ethanol feeding enhances age-related deterioration of the rat hepatic mitochondrion. Am J Physiol Gastrointest Liver Physiol 2005; 289:G1115-23. [PMID: 16020655 PMCID: PMC1634830 DOI: 10.1152/ajpgi.00193.2005] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
Chronic ethanol feeding damages the hepatic mitochondrion by increasing mitochondrial DNA (mtDNA) oxidation, lowering mtDNA yields and impairing mitochondrial respiration. These effects are also seen during aging. By employing a 21-day chronic feeding regimen, we investigated the effects of ethanol consumption on mtDNA content and mitochondrial respiration in 2-, 12-, and 24-mo-old male rats. Aging resulted in decreased mtDNA content, increased mtDNA damage (as indicated by inhibition of Taq polymerase progression), and a decline in state 3 respiration; effects that were further exacerbated by ethanol feeding. Additionally, ethanol consumption caused an increase in the levels of citrate synthase while not impacting mitochondrial protein content. In conclusion, ethanol and aging combine to cause deterioration in the structural and functional integrity of the hepatic mitochondrion. The additive effects of aging and ethanol feeding may have serious consequences for hepatic energy metabolism in aged animals, and their detrimental combination may serve as one of the molecular mechanisms underlying the progression of alcoholic liver disease.
Collapse
Affiliation(s)
- Alan Cahill
- Dept. of Pathology, Anatomy, and Cell Biology, Thomas Jefferson University, Philadelphia, PA 19107, USA.
| | | | | | | |
Collapse
|
26
|
Xu Y, Liu P, Li Y. Impaired development of mitochondria plays a role in the central nervous system defects of fetal alcohol syndrome. ACTA ACUST UNITED AC 2005; 73:83-91. [PMID: 15690350 DOI: 10.1002/bdra.20110] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
BACKGROUND Alcohol consumption during pregnancy can induce a wide spectrum of adverse effects in offspring. Microcephaly and mental retardation are two major defects of central nervous system (CNS). Most mechanism studies of alcohol-related CNS defects have been focused on the morphologically abnormal tissues, and more attention has been paid to nuclear alteration as opposed to organelle development. METHODS A mouse model of fetal alcohol syndrome (FAS) was used to investigate the effect of alcohol on fetal cerebral mitochondria development. Pregnant mice were given different doses of ethanol intragastrically from GD6 to GD15. Fetal cerebral mitochondria were isolated and analyzed on GD18. RESULTS Excessive cell apoptosis was found in the cerebra of prenatal alcohol exposure fetuses. Proliferation and differentiation of fetal cerebral mitochondria were inhibited by alcohol. Affected mitochondrial volume constriction and adenosine triphosphate (ATP) accumulation, reduced activities of respiratory chain complex I and IV and ATP synthase were detected in the cerebral tissue without obvious malformed appearance. CONCLUSIONS Impaired mitochondria development plays a role in the CNS defects induced by prenatal alcohol exposure.
Collapse
Affiliation(s)
- Yajun Xu
- Department of Nutrition and Food Hygiene, School of Public Health, Laboratory of Molecular Toxicology and Developmental Molecular Biology, Peking University, Beijing, China
| | | | | |
Collapse
|
27
|
Venkatraman A, Shiva S, Wigley A, Ulasova E, Chhieng D, Bailey SM, Darley-Usmar VM. The role of iNOS in alcohol-dependent hepatotoxicity and mitochondrial dysfunction in mice. Hepatology 2004; 40:565-73. [PMID: 15349894 DOI: 10.1002/hep.20326] [Citation(s) in RCA: 85] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
Nitric oxide (NO) is now known to control both mitochondrial respiration and organelle biogenesis. Under conditions of ethanol-dependent hepatic dysfunction, steatosis is increased, and this is associated with increased expression of inducible nitric oxide synthase (iNOS). We have previously shown that after chronic exposure to ethanol, the sensitivity of mitochondrial respiration to inhibition by NO is enhanced, and we have proposed that this contributes to ethanol-dependent hypoxia. This study examines the role of iNOS in controlling the NO-dependent modification of mitochondrial function. Mitochondria were isolated from the livers of both wild-type (WT) and iNOS knockout (iNOS-/-) mice that were fed an isocaloric ethanol-containing diet for a period of 5 weeks. All animals that consumed ethanol showed some evidence of fatty liver; however, this was to a lesser extent in the iNOS-/- mice compared to controls. At this early stage in ethanol-dependent hepatic dysfunction, infiltration of inflammatory cells and the formation of nitrated proteins was also decreased in response to ethanol feeding in the iNOS-/- animals. Mitochondria isolated from wild-type ethanol-fed mice showed a significant decrease in respiratory control ratio and an increased sensitivity to NO-dependent inhibition of respiration relative to their pair-fed controls. In contrast, liver mitochondria isolated from iNOS-/- mice fed ethanol showed no change in the sensitivity to NO-dependent inhibition of respiration. In conclusion, the hepatic response to chronic alcohol-dependent cytotoxicity involves a change in mitochondrial function dependent on the induction of iNOS.
Collapse
Affiliation(s)
- Aparna Venkatraman
- Department of Pathology, University of Alabama at Birmingham, Birmingham, AL 35294, USA
| | | | | | | | | | | | | |
Collapse
|
28
|
Venkatraman A, Landar A, Davis AJ, Chamlee L, Sanderson T, Kim H, Page G, Pompilius M, Ballinger S, Darley-Usmar V, Bailey SM. Modification of the mitochondrial proteome in response to the stress of ethanol-dependent hepatotoxicity. J Biol Chem 2004; 279:22092-101. [PMID: 15033988 DOI: 10.1074/jbc.m402245200] [Citation(s) in RCA: 141] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
Mitochondria are particularly susceptible to increased formation of reactive oxygen and nitrogen species in the cell that can occur in response to pathological and xenobiotic stimuli. Proteomics can give insights into both mechanism of pathology and adaptation to stress. Herein we report the use of proteomics to evaluate alterations in the levels of mitochondrial proteins following chronic ethanol exposure in an animal model. Forty-three proteins showed differential expression, 13 increased and 30 decreased, as a consequence of chronic ethanol. Of these proteins, 25 were not previously known to be affected by chronic ethanol emphasizing the power of proteomic approaches in revealing global responses to stress. Both nuclear and mitochondrially encoded gene products of the oxidative phosphorylation complexes in mitochondria from ethanol-fed rats were decreased suggesting an assembly defect in this integrated metabolic pathway. Moreover mtDNA damage was increased by ethanol demonstrating that the effects of ethanol consumption extend beyond the proteome to encompass mtDNA. Taken together, we have demonstrated that chronic ethanol consumption extends to a modification of the mitochondrial proteome far broader than realized previously. These data also suggest that the response of mitochondria to stress may not involve non-discriminate changes in the proteome but is restricted to those metabolic pathways that have a direct role in a specific pathology.
Collapse
Affiliation(s)
- Aparna Venkatraman
- Department of Pathology, University of Alabama, Birmingham, Alabama 35294, USA
| | | | | | | | | | | | | | | | | | | | | |
Collapse
|
29
|
Venkatraman A, Shiva S, Davis AJ, Bailey SM, Brookes PS, Darley-Usmar VM. Chronic alcohol consumption increases the sensitivity of rat liver mitochondrial respiration to inhibition by nitric oxide. Hepatology 2003; 38:141-7. [PMID: 12829996 DOI: 10.1053/jhep.2003.50293] [Citation(s) in RCA: 47] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
Chronic alcohol consumption is a well-known risk factor for hepatic injury, and mitochondrial damage plays a significant role in this process. Nitric oxide (NO) is an important modulator of mitochondrial function and is known to inhibit mitochondrial respiration. However, the impact of chronic alcohol consumption on NO-dependent control of liver mitochondrial function is unknown. This study examines the effect of alcohol exposure on liver mitochondria in a rat model and explores the interaction of NO and mitochondrial respiration in this context. Mitochondria were isolated from the liver of both control and ethanol-fed rats after 5 to 6 weeks of alcohol consumption. Mitochondria isolated from ethanol-treated rats showed a significant decrease in state 3 respiration and respiratory control ratio that was accompanied by an increased sensitivity to NO-dependent inhibition of respiration. In conclusion, we show that chronic alcohol consumption leads to increased sensitivity to the inhibition of respiration by NO. We propose that this results in a greater vulnerability to hypoxia and the development of alcohol-induced hepatotoxicity.
Collapse
Affiliation(s)
- Aparna Venkatraman
- Department of Pathology, University of Alabama at Birmingham, Birmingham, AL 35294, USA
| | | | | | | | | | | |
Collapse
|
30
|
Bailey SM. A review of the role of reactive oxygen and nitrogen species in alcohol-induced mitochondrial dysfunction. Free Radic Res 2003; 37:585-96. [PMID: 12868485 DOI: 10.1080/1071576031000091711] [Citation(s) in RCA: 73] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
Abstract
Our understanding of the mechanisms involved in the development of alcohol-induced liver disease has increased substantially in recent years. Specifically, reactive oxygen and nitrogen species have been identified as key components in initiating and possibly sustaining the pathogenic pathways responsible for the progression from alcohol-induced fatty liver to alcoholic hepatitis and cirrhosis. Ethanol has been demonstrated to increase the production of reactive oxygen and nitrogen species and decrease several antioxidant mechanisms in liver. However, the relative contribution of the proposed sites of ethanol-induced reactive species production within the liver is still not clear. It has been proposed that chronic ethanol-elicited alterations in mitochondria structure and function might result in increased production of reactive species at the level of the mitochondrion in liver from ethanol consumers. This in turn might result in oxidative modification and inactivation of mitochondrial macromolecules, thereby contributing further to mitochondrial dysfunction and a loss in hepatic energy conservation. Moreover, ethanol-related increases in reactive species may shift the balance between pro- and anti-apoptotic factors such that there is activation of the mitochondrial permeability transition, which would lead to increased cell death in the liver after chronic alcohol consumption. This article will examine the critical role of these reactive species in ethanol-induced liver injury with specific emphasis on how chronic ethanol-associated alterations to mitochondria influence the production of reactive oxygen and nitrogen species and how their production may disrupt hepatic energy conservation in the chronic alcohol abuser.
Collapse
Affiliation(s)
- Shannon M Bailey
- Department of Environmental Health Sciences and Center for Free Radical Biology, School of Public Health, The University of Alabama at Birmingham, 1530 3rd Avenue South, Ryals Building, Room 623, Birmingham, AL 35294, USA.
| |
Collapse
|
31
|
Patel VB, Chaurand P, Caprioli RM, Austen BM, Frears ER, Manca F, Davies H, Vrana KE, Wheeler M, Preedy VR. Emerging techniques in biomedical research and their application to alcohol toxicity. Alcohol Clin Exp Res 2003; 27:348-53. [PMID: 12605084 DOI: 10.1097/01.alc.0000052580.14492.21] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
This article represents the proceedings of a symposium at the 2002 RSA-ISBRA Meeting in San Francisco. The chairs were Vinood B. Patel and Victor R. Preedy. The presentations were (1) Macromolecular structural analysis, by Vinood B. Patel; (2) Profiling and imaging of proteins in tissue sections using mass spectrometry as a discovery tool in biological research, by Pierre Chaurand and Richard M. Caprioli; (3) The use of SELDI ProteinChip trade mark arrays, by Brian M. Austen, Emma R. Frears, Francesca Manca, and Huw Davies; (4) DNA hybridization array technologies, by Kent E. Vrana; and (5) Adeno- and adeno-associated viral mediated gene transfer approaches for alcoholic liver disease, by Michael Wheeler. Concluding remarks were by Victor R. Preedy.
Collapse
Affiliation(s)
- Vinood B Patel
- Department of Biochemistry and the Center for the Neurobehavioral Study of Alcohol, North Carolina, USA
| | | | | | | | | | | | | | | | | | | |
Collapse
|
32
|
Cahill A, Cunningham CC, Adachi M, Ishii H, Bailey SM, Fromenty B, Davies A. Effects of alcohol and oxidative stress on liver pathology: the role of the mitochondrion. Alcohol Clin Exp Res 2002. [PMID: 12068261 DOI: 10.1111/j.1530-0277.2002.tb02621.x] [Citation(s) in RCA: 105] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
This article represents the proceedings of a symposium at the 2001 Research Society on Alcoholism meeting in Montreal, Canada. The chairs were Alan Cahill and Carol C. Cunningham. The presentations were (1) Mitochondrial regulation of ethanol-induced hepatocyte apoptosis: possible involvement of proapoptotic Bcl-2 family protein Bax, by Masayuki Adachi and Hiromasa Ishii; (2) Effects of ethanol on mitochondrial reactive oxygen species production and oxidative protein modification, by Shannon M. Bailey; (3) Acute ethanol binges elicit widespread oxidative mitochondrial DNA damage and depletion: protective effects of antioxidants and inhibitors of ethanol metabolism, by Bernard Fromenty; and (4) Effects of chronic ethanol consumption upon hepatic mtDNA oxidative modification and depletion, by Alan Cahill and Adrian Davies.
Collapse
Affiliation(s)
- Alan Cahill
- Department of Pathology, Anatomy and Cell Biology, Thomas Jefferson University, Philadelphia, Pennsylvania 19107, USA.
| | | | | | | | | | | | | |
Collapse
|
33
|
Effects of Alcohol and Oxidative Stress on Liver Pathology: The Role of the Mitochondrion. Alcohol Clin Exp Res 2002. [DOI: 10.1097/00000374-200206000-00022] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
|
34
|
Patel VB, Cunningham CC. Altered hepatic mitochondrial ribosome structure following chronic ethanol consumption. Arch Biochem Biophys 2002; 398:41-50. [PMID: 11811947 DOI: 10.1006/abbi.2001.2701] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Chronic ethanol consumption decreases the synthesis of all 13 polypeptides encoded by the hepatic mitochondrial genome. This alteration in mitochondrial protein synthesis is due to modifications in mitochondrial ribosomes. In the current study, the nature of these alterations was investigated by determining some of the hydrodynamic properties, namely sedimentation coefficient, shape, and mass of mitochondrial ribosomes. The effect of ethanol consumption on the capacity for mitochondrial ribosomes to translate proteins was also determined using an in vitro Poly (U) assay system. Rats were fed the Lieber-DeCarli diet for 31 days with ethanol as 36% of total calories. The sedimentation coefficient, measured by sedimentation velocity analyses, was slightly, but significantly lower in ethanol mitochondrial ribosomes (53.2 +/- 0.5S) when compared with pair-fed controls (54.1 +/- 0.5S) (P = 0.04). Mitochondrial ribosomes from ethanol-fed animals also had a greater tendency to dissociate into subunits. The diffusion coefficient, determined by dynamic light scattering, was lower in mitochondrial ribosomes from ethanol-fed rats than pair-fed controls and this indicated a significantly greater diameter for ethanol ribosomes (42.1 +/- 0.2 nm) than for preparations from pair-fed controls (39.1 +/- 0.5 nm; P = 0.008). These alterations to ethanol mitochondrial ribosomes occurred despite no change in molecular mass, which suggested a significant ethanol-related shape change in the ribosomes. The translation capacity of mitochondrial ribosome preparations from ethanol-fed animals was markedly reduced due to dissociation of the monosome into light and heavy subunits. In summary, these observations demonstrate that chronic ethanol consumption causes significant structural and functional alterations to mitochondrial ribosomes. The loss in ribosome function leads to impaired mitochondrial polypeptide synthesis and is an example of a pathology giving rise to an alteration in the mitochondrial ribosome structure.
Collapse
Affiliation(s)
- Vinood B Patel
- Department of Biochemistry, Wake Forest University School of Medicine, Medical Center Boulevard, Winston-Salem, North Carolina 27157-1016, USA
| | | |
Collapse
|
35
|
Medina JM, López-Mediavilla C, Orfao A. Flow cytometry of isolated mitochondria during development and under some pathological conditions. FEBS Lett 2002; 510:127-32. [PMID: 11801239 DOI: 10.1016/s0014-5793(01)03260-4] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Mitochondria play an essential role in the generation of the energy needed for eukaryotic cell life and in the release of molecules involved in initiation of cell death. Here we review the changes in isolated mitochondrial fluorescent populations as distinguished by flow cytometry during postnatal development and their regulation by thyroid hormones and catecholamines. The use of flow cytometry in the study of mitochondrial changes occurring under hypothyroidism, alcohol abuse and aging is also reviewed.
Collapse
Affiliation(s)
- José M Medina
- Departmento de Bioquimica y Biologia Molecular, Facultad de Farmacia, Universidad de Salamanca, Spain
| | | | | |
Collapse
|
36
|
Bailey SM, Cunningham CC. Contribution of mitochondria to oxidative stress associated with alcoholic liver disease. Free Radic Biol Med 2002; 32:11-6. [PMID: 11755312 DOI: 10.1016/s0891-5849(01)00769-9] [Citation(s) in RCA: 222] [Impact Index Per Article: 10.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
The importance of oxidative stress in the development of alcoholic liver disease has long been appreciated. The mechanism by which ethanol triggers an increase in reactive oxygen species in the liver is complex, however, recent findings suggest that the mitochondrion may contribute significantly to the overall increase in oxidant levels in hepatocytes exposed to ethanol acutely or chronically. This review is focused on observations which indicate that the ability of ethanol to increase mitochondrial reactive oxygen species production is linked to its metabolism via oxidative processes and/or ethanol-related alterations to the mitochondrial electron transport chain. Furthermore, the capacity of ethanol-elicited increases in reactive oxygen species to oxidatively modify and inactivate mitochondrial proteins is highlighted as a mechanism by which ethanol might further disrupt the structure and function of mitochondria.
Collapse
Affiliation(s)
- Shannon M Bailey
- Department of Environmental Health Sciences, School of Public Health, University of Alabama at Birmingham, 1530 3rd Ave. South, RPHB 317, Birmingham, AL 35294, USA.
| | | |
Collapse
|
37
|
Li HS, Zhang JY, Thompson BS, Deng XY, Ford ME, Wood PG, Stolz DB, Eagon PK, Whitcomb DC. Rat mitochondrial ATP synthase ATP5G3: cloning and upregulation in pancreas after chronic ethanol feeding. Physiol Genomics 2001; 6:91-8. [PMID: 11459924 DOI: 10.1152/physiolgenomics.2001.6.2.91] [Citation(s) in RCA: 42] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Individuals with chronic excessive alcohol ingestion are put at the risk of acute and chronic pancreatitis. Underlying molecular mechanisms are unknown. Differential gene expression in the pancreas was profiled using mRNA differential display by comparison between control and ethanol-consuming rats. Male Wistar rats were fed with diets containing 6.7% (vol/vol) ethanol for 4 wk. A cDNA tag that was overexpressed in the pancreas of rats fed ethanol was isolated. A 723-bp cDNA was cloned from a rat pancreatic cDNA library, which encodes a novel rat mitochondrial ATP synthase subunit 9, isoform 3 (ATP5G3), which is homologous to a human ATP5G3 gene. Real-time PCR demonstrated that all three nuclear gene isoforms (ATP5G1, ATP5G2, and ATP5G3) were consistently upregulated in the pancreas of alcohol-consuming rats, parallel with mitochondrial injury. The cellular response to mitochondrial damage and metabolic stress may reflect an adaptive process for mitochondrial repair in pancreatic acinar cells during chronic ethanol ingestion.
Collapse
Affiliation(s)
- H S Li
- Department of Medicine, Center for Genomic Sciences, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania 15213, USA
| | | | | | | | | | | | | | | | | |
Collapse
|
38
|
Cunningham CC, Preedy VR, Paice AG, Hesketh JE, Peters TJ, Patel VB, Volpi E, Mawatari K, Masaki H, Mori And M, Torii K. Ethanol and protein metabolism. Alcohol Clin Exp Res 2001; 25:262S-268S. [PMID: 11391081 DOI: 10.1097/00000374-200105051-00042] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
This article represents the proceedings of a workshop at the 2000 ISBRA Meeting in Yokohama, Japan. The chairs were Carol C. Cunningham and Victor R. Preedy. The presentations were (1) Ribosomal content, ribosomal localization and the levels of ribosomal protein mRNA and rRNA in rat skeletal muscle exposed to ethanol, by Alistair G. Paice, John E. Hesketh, Timothy J. Peters, and Victor R. Preedy; (2) Altered hepatic mitochondrial ribosome structure after chronic ethanol administration, by Vinood B. Patel and Carol C. Cunningham; (3) Clinical aspects of hepatic protein metabolism and alcohol, by Elena Volpi; and (4) Effects of oral intake of alanine plus glutamine on ethanol metabolism and ethanol-related depression in motor activity, by Kazunori Mawatari, H. Masaki, M. Mori, and Kunio Torii.
Collapse
MESH Headings
- Alanine/pharmacology
- Animals
- Central Nervous System Depressants/pharmacology
- Ethanol/pharmacology
- Glutamine/pharmacology
- Humans
- Liver/drug effects
- Liver/metabolism
- Mitochondria, Liver/drug effects
- Mitochondria, Liver/metabolism
- Motor Activity/drug effects
- Motor Activity/physiology
- Muscle, Skeletal/drug effects
- Muscle, Skeletal/metabolism
- RNA, Messenger/drug effects
- RNA, Messenger/metabolism
- RNA, Ribosomal, 18S/drug effects
- RNA, Ribosomal, 18S/metabolism
- Ribosomal Proteins/drug effects
- Ribosomal Proteins/metabolism
Collapse
Affiliation(s)
- C C Cunningham
- Department of Biochemistry, Wake Forest University School of Medicine, Winston-Salem, North Carolina, USA.
| | | | | | | | | | | | | | | | | | | | | |
Collapse
|
39
|
Cunningham CC, Preedy VR, Paice AG, Hesketh JE, Peters TJ, Patel VB, Volpi E, Mawatari K, Masaki H, Mori M, Torii K. Ethanol and Protein Metabolism. Alcohol Clin Exp Res 2001. [PMID: 11391081 DOI: 10.1111/j.1530-0277.2001.tb02406.x] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
|
40
|
Bailey SM, Patel VB, Young TA, Asayama K, Cunningham CC. Chronic Ethanol Consumption Alters the Glutathione/Glutathione Peroxidase-1 System and Protein Oxidation Status in Rat Liver. Alcohol Clin Exp Res 2001. [PMID: 11371722 DOI: 10.1111/j.1530-0277.2001.tb02273.x] [Citation(s) in RCA: 119] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
|
41
|
Patel VB, Cunningham CC, Hantgan RR. Physiochemical properties of rat liver mitochondrial ribosomes. J Biol Chem 2001; 276:6739-46. [PMID: 11106644 DOI: 10.1074/jbc.m005781200] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
In the present study, the physiochemical properties of rat liver mitochondrial ribosomes were examined and compared with Escherichia coli ribosomes. The sedimentation and translational diffusion coefficients as well as the molecular weight and buoyant density of rat mitochondrial ribosomes were determined. Sedimentation coefficients were established using the time-derivative algorithm (Philo, J. S. (2000) Anal. Biochem. 279, 151-163). The sedimentation coefficients of the intact monosome, large subunit, and small subunit were 55, 39, and 28 S, respectively. Mitochondrial ribosomes had a particle composition of 75% protein and 25% RNA. The partial specific volume was 0.688 ml/g, as determined from the protein and RNA composition. The buoyant density of formaldehyde-fixed ribosomes in cesium chloride was 1.41 g/cm(3). The molecular masses of mitochondrial and E. coli ribosomes determined by static light-scattering experiments were 3.57 +/- 0.14 MDa and 2.49 +/- 0.06 MDa, respectively. The diffusion coefficient obtained from dynamic light-scattering measurements was 1.10 +/- 0.01 x 10(-7) cm(2) s(-1) for mitochondrial ribosomes and 1.72 +/- 0.03 x 10(-7) cm(2) s(-1) for the 70 S E. coli monosome. The hydration factor determined from these hydrodynamic parameters were 4.6 g of water/g of ribosome and 1.3 g/g for mitochondrial and E. coli ribosomes, respectively. A calculated hydration factor of 3.3 g/g for mitochondrial ribosomes was also obtained utilizing a calculated molecular mass and the Svedberg equation. These measurements of solvation suggest that ribosomes are highly hydrated structures. They are also in agreement with current models depicting ribosomes as porous structures containing numerous gaps and tunnels.
Collapse
Affiliation(s)
- V B Patel
- Department of Biochemistry, Wake Forest University School of Medicine, Winston-Salem, North Carolina 27157-1016, USA
| | | | | |
Collapse
|
42
|
Abstract
Chronic ethanol feeding has been shown to decrease the number of functionally active mitochondrial ribosomes by 55%. In this work, 55S mitochondrial ribosomes were isolated from rat liver and their constitutive proteins characterized by two-dimensional polyacrylamide gel electrophoresis and quantified by densitometry. A total of 86 proteins were found to be associated with the mitochondrial ribosome. This compares with 70 isolated from cytoplasmic ribosomes. In addition, mitochondrial ribosomal proteins were found to be significantly less basic than their cytoplasmic counterparts. Chronic ethanol feeding was found to significantly decrease the levels of a number of constitutive proteins of the mitochondrial ribosome when compared to those isolated from pair-fed controls. Sucrose density gradient analyses revealed a significant decrease in the number of intact 55S ribosomes. It is suggested that ethanol-elicited alterations in specific constitutive proteins of the mitochondrial ribosome may lead to impaired assembly of the monosome and that this may result in lower levels of those displaying functional activity.
Collapse
Affiliation(s)
- A Cahill
- Department of Pathology, Anatomy and Cell Biology, Thomas Jefferson University, Philadelphia, PA 19107, USA.
| | | |
Collapse
|
43
|
Cahill A, Stabley GJ, Wang X, Hoek JB. Chronic ethanol consumption causes alterations in the structural integrity of mitochondrial DNA in aged rats. Hepatology 1999; 30:881-8. [PMID: 10498638 PMCID: PMC2647744 DOI: 10.1002/hep.510300434] [Citation(s) in RCA: 67] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/07/2022]
Abstract
Chronic ethanol consumption adversely affects the respiratory activity of rat liver mitochondria. It causes increased cellular production of oxygen radical species and selectively decreases mitochondrial glutathione (GSH) levels. Here we show, using Southern hybridization techniques on total rat genomic DNA, that long-term (11-13 months) ethanol feeding, using the Lieber-DeCarli diet, results in a 36% (P <.05; n = 4) decrease in hepatic mitochondrial DNA (mtDNA) levels when compared with paired controls. UV quantitation of mtDNA isolated from hepatic mitochondria showed that chronic ethanol intake (11-13 months) causes a 44% (P <.01; n = 6) decrease in the amount of mtDNA per milligram of mitochondrial protein. No significant decline in mtDNA levels was seen in ethanol-fed animals maintained on the diet for 1 to 5 months. Ethanol feeding caused a 42% (P <.01; n = 4) and a 132% (P <.05; n = 3) increase in 8-hydroxydeoxyguanosine (8-OHdG) formation in mtDNA in animals maintained on the diet for 3 to 6 months and 10 to 11 months, respectively. In addition, agarose gel electrophoresis revealed a 49% increase (P <.05; n = 3) in mtDNA single-strand breaks (SSB) in animals fed ethanol for more than 1 year. These findings suggest that chronic ethanol consumption causes enhanced oxidative damage to mtDNA in older animals along with increased strand breakage, and that this results in its selective removal/degradation by mtDNA repair enzymes.
Collapse
Affiliation(s)
- A Cahill
- Department of Pathology, Anatomy, and Cell Biology, Thomas Jefferson University, Philadelphia, PA, USA.
| | | | | | | |
Collapse
|
44
|
Bailey SM, Cunningham CC. Effect of dietary fat on chronic ethanol-induced oxidative stress in hepatocytes. Alcohol Clin Exp Res 1999. [PMID: 10443988 DOI: 10.1111/j.1530-0277.1999.tb04280.x] [Citation(s) in RCA: 36] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
Abstract
BACKGROUND Although oxidative stress and deficits in hepatic energy metabolism have been implicated as important factors in the initiation of alcoholic liver disease, their relative contribution to ethanol-induced cell death is not known. The purpose of this study was to examine the effects of chronic ethanol administration on hepatocyte reactive oxygen species (ROS) generation, energy state, and viability, as well as the effect of dietary fat on these parameters. METHODS Male Sprague-Dawley rats were fed liquid diets that provided 36% total calories as ethanol, with fat as either 12% (low fat) or 35% (high fat) of total calories. Pair-fed controls received liquid diets in which maltose-dextrin was substituted for ethanol calories. The fluorescent probe 2',7'-dichlorofluorescin diacetate was used to detect ROS, lactate dehydrogenase leakage was used to assess viability, and ATP levels were used as a measure of the energy state. The effect of chronic ethanol feeding on these parameters was determined by incubating hepatocytes under a 5% oxygen-containing atmosphere or an atmosphere < or = 1% oxygen for 60 min. RESULTS In general, chronic ethanol feeding stimulated ROS production and decreased ATP concentrations, which were associated with decreased viability in hepatocytes isolated from rats fed either high- or low-fat, ethanol-containing diets, compared to the corresponding controls. Incubation under an atmosphere < or = 1% oxygen and/or ethanol (10 mM) augmented these effects in both high- and low-fat control and ethanol-fed hepatocytes. The addition of antimycin to the incubations increased ROS production, decreased ATP concentrations, and accelerated loss of hepatocyte viability. Viability loss under all conditions used in this study was correlated with decreases in cellular ATP. CONCLUSIONS Comparisons of incubations performed under the two oxygenation conditions revealed that viability loss was inversely associated with ROS production, which indicates that ATP loss and not ROS production was a better predictor of loss in cell integrity. This study also demonstrates that the level of dietary fat has only minor effects on generation of ROS and the cellular energy state. In contrast, ethanol consumption had significant effects on generation of ROS, energy state, and hepatocyte viability.
Collapse
Affiliation(s)
- S M Bailey
- Department of Biochemistry, Wake Forest University School of Medicine, Winston-Salem, NC 27157-1016, USA
| | | |
Collapse
|
45
|
Abstract
Ethanol and other short-chain alcohols elicit a number of cellular responses that are potentially cytotoxic and, to some extent, independent of cell type. Aberrations in phospholipid and fatty acid metabolism, changes in the cellular redox state, disruptions of the energy state, and increased production of reactive oxygen metabolites have been implicated in cellular damage resulting from acute or chronic exposure to short-chain alcohols. Resulting disruptions of intracellular signaling cascades through interference with the synthesis of phosphatidic acid, decreases in phosphorylation potential and lipid peroxidation are mechanisms by which solvent alcohols can affect the rate of cell proliferation and, consequently, cell number. Nonoxidative metabolism of short-chain alcohols, including phospholipase D-mediated synthesis of alcohol phospholipids, and the synthesis of fatty acid alcohol esters are additional mechanisms by which alcohols can affect membrane structure and compromise cell function.
Collapse
Affiliation(s)
- R C Baker
- Department of Pharmacology and Toxicology, University of Mississippi Medical Center, Jackson 39216-4505, USA.
| | | |
Collapse
|
46
|
Sebastian T, Setty OH. Protective effect of P. fraternus against ethanol-induced mitochondrial dysfunction. Alcohol 1999; 17:29-34. [PMID: 9895034 DOI: 10.1016/s0741-8329(98)00029-9] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
Chronic ethanol consumption (10 g per kg body weight) significantly decreased the rate of respiration, P/O ratio, and respiratory control ratio (RCR). The activities of NADH dehydrogenase and cytochrome oxidase were significantly decreased in submitochondrial particles by ethanol administration compared to control. No significant difference was observed in membrane potential of submitochondrial particles. Cytochrome b, c and aa3 content of mitochondria were significantly decreased by ethanol feeding. Ethanol-induced inhibition on rate of respiration, P/O ratio, and RCR was relieved to a great extent by the administration of the aqueous extract of Phyllanthus fraternus (100 mg dry powder of the plant per kg body weight) along with ethanol. The decrease in the content of cytochromes due to ethanol administration was revived partially by aqueous extract of P. fraternus.
Collapse
Affiliation(s)
- T Sebastian
- Department of Biochemistry, School of Life Sciences, University of Hyderabad, India
| | | |
Collapse
|
47
|
Bailey SM, Cunningham CC. Acute and chronic ethanol increases reactive oxygen species generation and decreases viability in fresh, isolated rat hepatocytes. Hepatology 1998; 28:1318-26. [PMID: 9794917 DOI: 10.1002/hep.510280521] [Citation(s) in RCA: 142] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Although reactive oxygen species (ROS) have been implicated in the etiology of alcohol-induced liver disease, neither their relative contribution to cell death nor the cellular mechanisms mediating their formation are known. The purpose of this study was to test the hypothesis that acute and chronic ethanol exposure enhances the mitochondrial generation of ROS in fresh, isolated hepatocytes. Acute ethanol exposure stimulated ROS production, increased the cellular NADH/NAD+ ratio, and decreased hepatocyte viability slightly, which was prevented by pretreatment with 4-methylpyrazole (4-MP), an inhibitor of alcohol dehydrogenase. Similarly, xylitol, an NADH-generating compound, enhanced hepatocyte ROS production and decreased viability. Incubation with pyruvate, an NADH-oxidizing compound, and cyanamide, an inhibitor of aldehyde dehydrogenase, significantly decreased ROS levels in acute ethanol-treated hepatocytes. Chronic ethanol consumption produced a sixfold increase in hepatocyte ROS production compared with levels measured in controls. Hepatocytes from ethanol-fed rats were less viable compared with controls, e.g., viability was 68% +/- 2% (ethanol) versus 83% +/- 1% (control) after 60 minutes of incubation. Antimycin A increased ROS production and decreased cell viability; however, the toxic effect of antimycin A was more pronounced in ethanol-fed hepatocytes. These results suggest that acute and chronic ethanol exposure exacerbates mitochondrial ROS production, contributing to cell death.
Collapse
Affiliation(s)
- S M Bailey
- Department of Biochemistry, Wake Forest University School of Medicine, Winston-Salem, NC, USA
| | | |
Collapse
|
48
|
Matsuhashi T, Karbowski M, Liu X, Usukura J, Wozniak M, Wakabayashi T. Complete suppresion of ethanol-induced formation of megamitochondria by 4-hydroxy-2,2,6,6-tetramethyl-piperidine-1-oxyl (4-OH-TEMPO). Free Radic Biol Med 1998; 24:139-47. [PMID: 9436623 DOI: 10.1016/s0891-5849(97)00210-4] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
An attempt has been made to suppress the ethanol-induced formation of megamitochondria (MG) in the rat liver by 4-hydroxy-2,2,6,6-tetramethyl-piperidine-1-oxyl (4-OH-TEMPO), a free radical scavenger, and by allopurinol (AP), a xanthine oxidase inhibitor. Changes observed in the liver of animals given ethanol (EtOH) for 1 month were remarkable decreases both in the body weight gains during the course of the experiment and in the liver weight at the time of sacrifice compared to those of the control; remarkable increases in the level of thiobarbituric acid reactive substances and lipid soluble fluorophores both in microsomes and mitochondria; decreases in the content of cytochrome a+a3 and b and lowered phosphorylating ability of mitochondria; and formation of MG in the liver. A combined treatment of animals with EtOH plus 4-OH-TEMPO completely suppressed the formation of MG in the liver induced by EtOH and distinctly improved the changes caused by EtOH, as specified above, while AP partly suppressed the MG formation. Results described herein provide additional insight into chronic hepatotoxicity of EtOH besides that previously reported. A novelty of the present work is that we were able for the first time to demonstrate reversibility of EtOH-mediated ultrastructural changes of the liver by a simple administration of aminoxyl-type free radical scavenger, 4-OH-TEMPO. Our results suggest that free radicals may be involved in the mechanism of the formation of MG induced by EtOH.
Collapse
Affiliation(s)
- T Matsuhashi
- Department of Cell Biology and Molecular Pathology, Nagoya University School of Medicine, Japan
| | | | | | | | | | | |
Collapse
|
49
|
Mansouri A, Fromenty B, Berson A, Robin MA, Grimbert S, Beaugrand M, Erlinger S, Pessayre D. Multiple hepatic mitochondrial DNA deletions suggest premature oxidative aging in alcoholic patients. J Hepatol 1997; 27:96-102. [PMID: 9252080 DOI: 10.1016/s0168-8278(97)80286-3] [Citation(s) in RCA: 113] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
BACKGROUND/AIMS A 4977-base pair deletion has been detected in the hepatic mitochondrial DNA of alcoholic patients with microvesicular steatosis, a lesion ascribed to impaired mitochondrial beta-oxidation. However, only a single deletion had been looked for in this previous study, and it could not be determined whether the deletion was preexisting or acquired. Alcohol abuse increases the formation of reactive oxygen species in hepatic mitochondria. If this effect accelerates the oxidative aging of mitochondrial DNA, several other mutations would be expected. METHODS The mtDNA region extending from nucleotide 8167 to nucleotide 14246 was screened for the presence of large mitochondrial DNA deletions in 58 alcoholic patients and 67 age-matched non-alcoholic controls. Hepatic DNA was subjected to polymerase chain reactions that amplified non-deleted and deleted mitochondrial DNA, respectively, and the boundaries of the mitochondrial DNA deletions were sequenced. RESULTS Only 3% of the non-alcoholic controls carried a mitochondrial DNA deletion, whereas 24% of all alcoholic patients and 85% of the 13 alcoholic patients with microvesicular steatosis exhibited either single or multiple 4977, 5385, 5039 and 5556-base pair mitochondrial DNA deletions. No deletion(s) were observed, however, in 13 patients with microvesicular steatosis due to other causes. CONCLUSIONS Diverse mitochondrial DNA rearrangements are observed in alcoholic patients with microvesicular steatosis. We suggest that alcohol abuse leads to premature oxidative aging of mitochondrial DNA. Hypothetically, oxidative damage to mitochondrial constituents (DNA, proteins and lipids) may favor microvesicular fat deposition.
Collapse
Affiliation(s)
- A Mansouri
- INSERM Unité 24 and Centre de Recherche de Physiopathologie Hépatique(Association Claude Bernard), Hôpital Beaujon, Clichy, France
| | | | | | | | | | | | | | | |
Collapse
|
50
|
Cahill A, Wang X, Hoek JB. Increased oxidative damage to mitochondrial DNA following chronic ethanol consumption. Biochem Biophys Res Commun 1997; 235:286-90. [PMID: 9199183 DOI: 10.1006/bbrc.1997.6774] [Citation(s) in RCA: 93] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
Ethanol consumption adversely affects the structural and functional integrity of hepatic mitochondria. Some of these effects may arise from the increased cellular levels of oxidizing radicals induced by ethanol feeding. Since DNA is a potential target of free radical damage, we investigated the effect of chronic ethanol feeding on oxidative modification of mtDNA. Mitochondria were isolated from the livers of control and ethanol-fed rats and the mtDNA analyzed for the presence of 8-hydroxydeoxyguanosine (8-OHdG). A 21% increase in the level of 8-OHdG was detected in mtDNA from animals that had been fed an ethanol-containing diet for 42-76 days (control, 3.98 +/- 0.5; ethanol, 4.8 +/- 0.9 8-OHdG/100,000dG). This difference increased to 43% in animals that had been fed ethanol for 105-164 days (control, 6.9 +/- 1.0; ethanol, 9.9 +/- 1.1 8-OHdG/100,000dG). This increase in mtDNA oxidation was accompanied by a decrease in the recovery of mtDNA (42-76 days: control, 88 +/- 11; ethanol 76 +/- 8 ng/mg mitochondrial protein; 105-164 days: control, 88 +/- 13; ethanol 62 +/- 14 ng/mg mitochondrial protein). The data presented demonstrate that chronic ethanol feeding leads to increased oxidative damage of hepatic mtDNA. This may in turn result in progressive mtDNA mutations and deletions and impaired mitochondrial function.
Collapse
Affiliation(s)
- A Cahill
- Department of Pathology, Anatomy and Cell Biology, Thomas Jefferson University, Philadelphia, Pennsylvania 19107, USA.
| | | | | |
Collapse
|