1
|
Singal AK, Shah VH, Malhi H. Emerging targets for therapy in ALD: Lessons from NASH. Hepatology 2024; 80:223-237. [PMID: 36938877 PMCID: PMC10511666 DOI: 10.1097/hep.0000000000000381] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/26/2022] [Accepted: 03/09/2023] [Indexed: 03/21/2023]
Abstract
Alcohol-associated liver disease due to harmful alcohol use and NAFLD associated with metabolic syndrome are the 2 most common liver diseases worldwide. Control of respective risk factors is the cornerstone in the long-term management of these diseases. Furthermore, there are no effective therapies. Both diseases are characterized by metabolic derangements; thus, the focus of this review was to broaden our understanding of metabolic targets investigated in NAFLD, and how these can be applied to alcohol-associated liver disease. Conserved pathogenic pathways such as dysregulated lipid metabolism, cell death pathways including apoptosis and activation of innate immune cells, and stellate cells mediate both alcohol and NAFLDs, resulting in histological abnormalities of steatosis, inflammation, fibrosis, and cirrhosis. However, pathways such as gut microbiome changes, glucose metabolism and insulin resistance, inflammatory signaling, and microRNA abnormalities are distinct in these 2 diseases. In this review article, we describe conserved and distinct pathogenic pathways highlighting therapeutic targets that may be of potential in both diseases and those that are unique to each disease.
Collapse
Affiliation(s)
- Ashwani K. Singal
- Department of Internal Medicine, University of South Dakota Sanford School of Medicine, Sioux Falls, South Dakota, USA
- Division of Gastroenterology and Hepatology, Avera Transplant Institute, Sioux Falls, South Dakota, USA
- VA Medical Center, Sioux Falls, South Dakota, USA
| | - Vijay H. Shah
- Division of Gastroenterology and Hepatology, Mayo Clinic, Rochester, Minnesota, USA
| | - Harmeet Malhi
- Division of Gastroenterology and Hepatology, Mayo Clinic, Rochester, Minnesota, USA
| |
Collapse
|
2
|
DafaAlla TEIM, Abdalla M, El-Arabey AA, Eltayb WA, Mohapatra RK. Botrytis cinerea alcohol dehydrogenase mediates fungal development, environmental adaptation and pathogenicity. J Biomol Struct Dyn 2022; 40:12426-12438. [PMID: 34472419 DOI: 10.1080/07391102.2021.1971112] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
Botrytis cinerea is an economically critical necrotrophic fungus that infecting many types of plants species. Although the lifestyle adaptations and genetic foundations of several enzymes and metabolites involved in B. cinerea virulence during host plant infection are well studied, the role of B. cinerea alcohol dehydrogenase (ADH) enzymes in these processes is poorly understood. Herein, we identified a significant up-regulation of the transcriptional levels of the BcADH1 gene during the tomato - B. cinerea strain B0510 interaction and at the early stage of infection. Substantially, we used a recent approach for replacement of gene by utilizing homologous recombination to generate knock-out mutants (Δbcadh1) and their effective complementary strains (Δbcadh1/C). A strong difference in the morphology of Δbcadh1 mutants from the wild type (WT) was detected, with respect to the conidiospore, conidial germination, and formation of branches, sporulation and sclerotia. In addition, the Δbcadh1 mutants showed significant differences in their virulence on tomato leaves relative to the WT. Moreover, the Δbcadh1 mutants appeared to have higher sensitivity to oxygen limitation (hypoxia) and reactive oxygen species, and had lost their ability of alcoholic fermentation compared with the WT and complementary strains. These results provide strong evidence for the requirement of the ADH1 gene for fungal development, environmental adaptation and its ability for full pathogenicity.Communicated by Ramaswamy H. Sarma.
Collapse
Affiliation(s)
- Tayb Elassma I M DafaAlla
- College of Plant Sciences, Jilin University, Changchun, China.,College of Natural Resources and Environmental Studies, Sinnar University, Sinnar, Sudan
| | - Mohnad Abdalla
- Key Laboratory of Chemical Biology (Ministry of Education), Department of Pharmaceutics, School of Pharmaceutical Sciences, Cheeloo College of Medicine, Shandong University, Jinan, PR China
| | - Amr Ahmed El-Arabey
- Department of Pharmacology and Toxicology, Faculty of Pharmacy, Al-Azhar University, Cairo, Egypt
| | - Wafa Ali Eltayb
- Department biotechnology, Faculty of Science and Technology, Shendi University, Shendi, Sudan
| | - Ranjan K Mohapatra
- Department of Chemistry, Government College of Engineering, Keonjhar, Keonjhar, India
| |
Collapse
|
3
|
Koga T, Peters JM. Targeting Peroxisome Proliferator-Activated Receptor-β/δ (PPARβ/δ) for the Treatment or Prevention of Alcoholic Liver Disease. Biol Pharm Bull 2021; 44:1598-1606. [PMID: 34719638 DOI: 10.1248/bpb.b21-00486] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Excessive, chronic alcohol consumption can lead to alcoholic liver disease. The etiology of alcoholic liver disease is multifactorial and is influenced by alterations in gene expression and changes in fatty acid metabolism, oxidative stress, and insulin resistance. These events can lead to steatosis, fibrosis, and eventually to cirrhosis and liver cancer. Many of these functions are regulated by peroxisome proliferator-activated receptors (PPARs). Thus, it is not surprising that PPARs can modulate the mechanisms that cause alcoholic liver disease. While the roles of PPARα and PPARγ are clearer, the role of PPARβ/δ in alcoholic liver disease requires further clarification. This review summarizes the current understanding based on recent studies that indicate that PPARβ/δ can likely be targeted for the treatment and/or the prevention of alcoholic liver disease.
Collapse
Affiliation(s)
- Takayuki Koga
- Laboratory of Hygienic Chemistry, Department of Health Science and Hygiene, Daiichi University of Pharmacy
| | - Jeffrey M Peters
- Department of Veterinary and Biomedical Sciences and the Center of Molecular Toxicology and Carcinogenesis, The Pennsylvania State University
| |
Collapse
|
4
|
Koc G, Kuskonmaz SM, Demirel K, Koca G, Akbulut A, Yumusak N, Senes M, Kirtil G, Korkmaz M, Culha C. Ameliorating effects of N-acetyl cysteine against early liver damage of radioiodine in rats. Nucl Med Commun 2021; 42:1195-1201. [PMID: 34149008 DOI: 10.1097/mnm.0000000000001454] [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: 11/25/2022]
Abstract
OBJECTIVE The present study was aimed to explore the potential ameliorating effects of N-acetyl cysteine (NAC) against radioiodine (RAI)-induced early liver damage. METHODS Thirty Wistar Albino male rats were arbitrarily allocated into three groups each containing 10 rats: the control group (group 1); the RAI group (group 2), oral 111 MBq/kg radioiodine was administered to rats; the RAI + NAC group (group 3), 150 mg/kg/day intraperitoneal NAC treatment was initiated 3 days prior to the RAI administration and continued for 10 days. Liver samples were obtained 24 h after the last dose of NAC therapy for biochemical and histopathologic evaluation. RESULTS In the RAI + NAC group, the histopathologic damage was found significantly less than in the RAI group for whole parameters except inflammatory cell infiltration (P < 0.05). Unlike the RAI group which had marked histopathologic damage, the RAI + NAC group had only mild histologic activity index scores with no granuloma formation observed. Oxidative stress parameters were demonstrated that the NAC treatment significantly decreased the tissue malondialdehyde (MDA) and catalase levels and increased the total sulfhydryl (total sulfhydryl) levels when compared to the RAI group (P < 0.01). CONCLUSION The outcomes of the study exhibited that the NAC treatment improved RAI-induced early liver damage. This improving effect considered to be caused by its antioxidant, anti-inflammatory, and likely vasodilator properties of NAC. Having advantages such as inexpensive, easy access, and tolerability, the NAC can be used as a radioprotective agent, especially in patients with liver diseases and requiring RAI treatment.
Collapse
Affiliation(s)
- Gonul Koc
- Department of Endocrinology and Metabolism
| | | | - Koray Demirel
- Department of Nuclear Medicine, University of Health Sciences, Ankara Training and Research Hospital, Ankara
| | - Gokhan Koca
- Department of Nuclear Medicine, University of Health Sciences, Ankara Training and Research Hospital, Ankara
| | - Aylin Akbulut
- Department of Nuclear Medicine, University of Health Sciences, Ankara Training and Research Hospital, Ankara
| | - Nihat Yumusak
- Department of Pathology, Harran University Faculty of Veterinary Medicine, Sanliurfa
| | - Mehmet Senes
- Department of Biochemistry, University of Health Sciences, Ankara Training and Research Hospital, Ankara, Turkey
| | - Gul Kirtil
- Department of Biochemistry, University of Health Sciences, Ankara Training and Research Hospital, Ankara, Turkey
| | - Meliha Korkmaz
- Department of Nuclear Medicine, University of Health Sciences, Ankara Training and Research Hospital, Ankara
| | | |
Collapse
|
5
|
Translational Approaches with Antioxidant Phytochemicals against Alcohol-Mediated Oxidative Stress, Gut Dysbiosis, Intestinal Barrier Dysfunction, and Fatty Liver Disease. Antioxidants (Basel) 2021; 10:antiox10030384. [PMID: 33806556 PMCID: PMC8000766 DOI: 10.3390/antiox10030384] [Citation(s) in RCA: 29] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2021] [Revised: 02/25/2021] [Accepted: 02/25/2021] [Indexed: 12/12/2022] Open
Abstract
Emerging data demonstrate the important roles of altered gut microbiomes (dysbiosis) in many disease states in the peripheral tissues and the central nervous system. Gut dysbiosis with decreased ratios of Bacteroidetes/Firmicutes and other changes are reported to be caused by many disease states and various environmental factors, such as ethanol (e.g., alcohol drinking), Western-style high-fat diets, high fructose, etc. It is also caused by genetic factors, including genetic polymorphisms and epigenetic changes in different individuals. Gut dysbiosis, impaired intestinal barrier function, and elevated serum endotoxin levels can be observed in human patients and/or experimental rodent models exposed to these factors or with certain disease states. However, gut dysbiosis and leaky gut can be normalized through lifestyle alterations such as increased consumption of healthy diets with various fruits and vegetables containing many different kinds of antioxidant phytochemicals. In this review, we describe the mechanisms of gut dysbiosis, leaky gut, endotoxemia, and fatty liver disease with a specific focus on the alcohol-associated pathways. We also mention translational approaches by discussing the benefits of many antioxidant phytochemicals and/or their metabolites against alcohol-mediated oxidative stress, gut dysbiosis, intestinal barrier dysfunction, and fatty liver disease.
Collapse
|
6
|
Barron KA, Jeffries KA, Krupenko NI. Sphingolipids and the link between alcohol and cancer. Chem Biol Interact 2020; 322:109058. [PMID: 32171848 DOI: 10.1016/j.cbi.2020.109058] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2019] [Revised: 11/20/2019] [Accepted: 03/10/2020] [Indexed: 02/07/2023]
Abstract
Epidemiological evidence underscores alcohol consumption as a strong risk factor for multiple cancer types, with liver cancer being most commonly associated with alcohol intake. While mechanisms linking alcohol consumption to malignant tumor development are not fully understood, the likely players in ethanol-induced carcinogenesis are genotoxic stress caused by formation of acetaldehyde, increased oxidative stress, and altered nutrient metabolism, including the impairment of methyl transfer reactions. Alterations of sphingolipid metabolism and associated signaling pathways are another potential link between ethanol and cancer development. In particular, ceramides are involved in the regulation of cellular proliferation, differentiation, senescence, and apoptosis and are known to function as important regulators of malignant transformation as well as tumor progression. However, to date, the cross-talk between ceramides and alcohol in cancer disease is largely an open question and only limited data are available on this subject. Most studies linking ceramide to cancer considered liver steatosis as the underlying mechanism, which is not surprising taking into consideration that ceramide pathways are an integral part of the overall lipid metabolism. This review summarizes the latest studies pointing to ceramide as an important mediator of cancer-promoting effects of chronic alcohol consumption and underscores the necessity of understanding the role of sphingolipids and lipid signaling in response to alcohol in order to prevent and/or successfully manage diseases caused by alcohol.
Collapse
Affiliation(s)
| | | | - Natalia I Krupenko
- Department of Nutrition, UNC Chapel Hill, USA; Nutrition Research Institute, UNC Chapel Hill, USA.
| |
Collapse
|
7
|
Mühle C, Weinland C, Gulbins E, Lenz B, Kornhuber J. Peripheral Acid Sphingomyelinase Activity Is Associated with Biomarkers and Phenotypes of Alcohol Use and Dependence in Patients and Healthy Controls. Int J Mol Sci 2018; 19:ijms19124028. [PMID: 30551571 PMCID: PMC6320816 DOI: 10.3390/ijms19124028] [Citation(s) in RCA: 25] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2018] [Revised: 11/30/2018] [Accepted: 12/04/2018] [Indexed: 01/04/2023] Open
Abstract
By catalyzing the hydrolysis of sphingomyelin into ceramide, acid sphingomyelinase (ASM) changes the local composition of the plasma membrane with effects on receptor-mediated signaling. Altered enzyme activities have been noted in common human diseases, including alcohol dependence. However, the underlying mechanisms remain largely unresolved. Blood samples were collected from early-abstinent alcohol-dependent in-patients (n[♂] = 113, n[♀] = 87) and matched healthy controls (n[♂] = 133, n[♀] = 107), and analyzed for routine blood parameters and serum ASM activity. We confirmed increased secretory ASM activities in alcohol-dependent patients compared to healthy control subjects, which decreased slightly during detoxification. ASM activity correlated positively with blood alcohol concentration, withdrawal severity, biomarkers of alcohol dependence (liver enzyme activities of gamma-glutamyl transferase, alanine aminotransferase, aspartate aminotransferase; homocysteine, carbohydrate-deficient transferrin; mean corpuscular volume, and creatine kinase). ASM activity correlated negatively with leukocyte and thrombocyte counts. ASM and gamma-glutamyl transferase were also associated in healthy subjects. Most effects were similar for males and females with different strengths. We describe previously unreported associations between ASM activity and markers of liver damage and myelosuppression. Further research should investigate whether this relationship is causal, or whether these parameters are part of a common pathway in order to gain insights into underlying mechanisms and develop clinical applications.
Collapse
Affiliation(s)
- Christiane Mühle
- Department of Psychiatry and Psychotherapy, Friedrich-Alexander University Erlangen-Nürnberg (FAU), D-91054 Erlangen, Germany.
| | - Christian Weinland
- Department of Psychiatry and Psychotherapy, Friedrich-Alexander University Erlangen-Nürnberg (FAU), D-91054 Erlangen, Germany.
| | - Erich Gulbins
- Department of Molecular Biology, University of Duisburg-Essen, D-45259 Essen, Germany.
- Department of Surgery, University of Cincinnati, Cincinnati, OH 45267-0558, USA.
| | - Bernd Lenz
- Department of Psychiatry and Psychotherapy, Friedrich-Alexander University Erlangen-Nürnberg (FAU), D-91054 Erlangen, Germany.
| | - Johannes Kornhuber
- Department of Psychiatry and Psychotherapy, Friedrich-Alexander University Erlangen-Nürnberg (FAU), D-91054 Erlangen, Germany.
| |
Collapse
|
8
|
Tomko RL, Jones JL, Gilmore AK, Brady KT, Back SE, Gray KM. N-acetylcysteine: A potential treatment for substance use disorders. CURRENT PSYCHIATRY 2018; 17:30-55. [PMID: 30016376 PMCID: PMC5993450] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Grants] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Affiliation(s)
- Rachel L Tomko
- Research Assistant Professor, Department of Psychiatry and Behavioral Sciences, Medical University of South Carolina, Charleston, South Carolina
| | - Jennifer L Jones
- Resident Physician, Departments of Psychiatry and Behavioral Sciences and Internal Medicine, Medical University of South Carolina, Charleston, South Carolina
| | - Amanda K Gilmore
- Assistant Professor, National Crime Victims Research & Treatment Center, Department of Psychiatry and Behavioral Sciences, Medical University of South Carolina, Charleston, South Carolina
| | - Kathleen T Brady
- Distinguished University Professor, Department of Psychiatry and Behavioral Sciences, Medical University of South Carolina, Charleston, South Carolina
| | - Sudie E Back
- Professor, Department of Psychiatry and Behavioral Sciences, Medical University of South Carolina, Charleston, South Carolina
| | - Kevin M Gray
- Professor, Department of Psychiatry and Behavioral Sciences, Medical University of South Carolina, Charleston, South Carolina
| |
Collapse
|
9
|
Kondakçı G, Aydın AF, Doğru-Abbasoğlu S, Uysal M. The effect of N-acetylcysteine supplementation on serum homocysteine levels and hepatic and renal oxidative stress in homocysteine thiolactone-treated rats. Arch Physiol Biochem 2017; 123:128-133. [PMID: 28100069 DOI: 10.1080/13813455.2016.1273365] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
The effect of N-acetylcysteine (NAC) (1 g/kg body weight/day) on serum homocysteine (Hcy) levels, insulin resistance (IR), and hepatic and renal prooxidant-antioxidant balance was evaluated in rats treated with homocysteine thiolactone (HcyT) (500 mg/kg body weight/day for 6 weeks). Reactive oxygen species (ROS), malondialdehyde (MDA), glutathione, ferric reducing antioxidant power, and superoxide dismutase (SOD) and glutathione peroxidase (GSH-Px) activities were determined in the liver and kidney. HcyT elevated serum Hcy levels and caused IR, but liver and kidney function tests remained unchanged. HcyT increased ROS and MDA without any change in hepatic antioxidants, but it elevated renal SOD and GSH-Px activities. NAC decreased serum Hcy, hepatic and renal ROS and MDA levels, and renal SOD and GSH-Px activities in rats with high Hcy levels. However, it did not ameliorate IR. Our results indicate that NAC supplementation may be effective in decreasing Hcy levels and Hcy-induced hepatic and renal oxidative stress.
Collapse
Affiliation(s)
- Gamze Kondakçı
- a Department of Biochemistry , Istanbul Medical Faculty, Istanbul University , Istanbul , Turkey
| | - A Fatih Aydın
- a Department of Biochemistry , Istanbul Medical Faculty, Istanbul University , Istanbul , Turkey
| | - Semra Doğru-Abbasoğlu
- a Department of Biochemistry , Istanbul Medical Faculty, Istanbul University , Istanbul , Turkey
| | - Müjdat Uysal
- a Department of Biochemistry , Istanbul Medical Faculty, Istanbul University , Istanbul , Turkey
| |
Collapse
|
10
|
Wang CY, Li XD, Hao ZH, Xu D. Insulin-like growth factor-1 improves diabetic cardiomyopathy through antioxidative and anti-inflammatory processes along with modulation of Akt/GSK-3β signaling in rats. THE KOREAN JOURNAL OF PHYSIOLOGY & PHARMACOLOGY : OFFICIAL JOURNAL OF THE KOREAN PHYSIOLOGICAL SOCIETY AND THE KOREAN SOCIETY OF PHARMACOLOGY 2016; 20:613-619. [PMID: 27847438 PMCID: PMC5106395 DOI: 10.4196/kjpp.2016.20.6.613] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/22/2016] [Revised: 09/09/2016] [Accepted: 09/10/2016] [Indexed: 12/13/2022]
Abstract
Diabetic cardiomyopathy (DCM), a serious complication of diabetes mellitus, is associated with changes in myocardial structure and function. This study sought to explore the ability of insulin-like growth factor-1 (IGF-1) to modulate DCM and its related mechanisms. Twenty-four male Wistar rats were injected with streptozotocin (STZ, 60 mg/kg) to mimic diabetes mellitus. Myocardial fibrosis and apoptosis were evaluated by histopathologic analyses, and relevant proteins were analyzed by Western blotting. Inflammatory factors were assessed by ELISA. Markers of oxidative stress were tested by colorimetric analysis. Rats with DCM displayed decreased body weight, metabolic abnormalities, elevated apoptosis (as assessed by the bcl-2/bax ratio and TUNEL assays), increased fibrosis, increased markers of oxidative stress (MDA and SOD) and inflammatory factors (TNF-α and IL-1β), and decreased phosphorylation of Akt and glycogen synthase kinase (GSK-3β). IGF-1 treatment, however, attenuated the metabolic abnormalities and myocardial apoptosis, interstitial fibrosis, oxidative stress and inflammation seen in diabetic rats, while also increasing the phosphorylation levels of Akt and GSK-3β. These findings suggest that IGF-1 ameliorates the pathophysiological progress of DCM along with an activation of the Akt/GSK-3β signaling pathway. Our findings suggest that IGF-1 could be a potential therapeutic choice for controlling DCM.
Collapse
Affiliation(s)
- Cheng Yu Wang
- Center of Morphological Experiment, Medical College of Yanbian University, Yanji 133000, Jilin Province, China
| | - Xiang Dan Li
- Center of Morphological Experiment, Medical College of Yanbian University, Yanji 133000, Jilin Province, China
| | - Zhi Hong Hao
- Center of Morphological Experiment, Medical College of Yanbian University, Yanji 133000, Jilin Province, China
| | - Dongyuan Xu
- Center of Morphological Experiment, Medical College of Yanbian University, Yanji 133000, Jilin Province, China
| |
Collapse
|
11
|
Molecular mechanism of hepatic steatosis: pathophysiological role of autophagy. Expert Rev Mol Med 2016; 18:e14. [PMID: 27499351 DOI: 10.1017/erm.2016.14] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
UNLABELLED Steatosis is an early characteristic in the pathogenesis of fatty liver disease (FLD). Mechanisms of hepatic steatosis are aetiology-dependent. Activation of autophagy in liver ameliorates hepatic steatosis. A modulation of hepatic autophagy affects the degree of hepatocyte steatosis and the progression of FLD as demonstrated by pre-clinical models and clinical trials. This review summarises recent advances on pathophysiological roles of autophagy in hepatic lipid metabolism. A comprehensive regulation of autophagic networks holds promise for the improvement of hepatic steatosis. Autophagic signalling pathway may be a novel therapeutic target against FLD. HIGHLIGHTS • Hepatic steatosis is a pathological condition wherein vacuoles of triglyceride (TG) fat are overaccumulated in liver because of abnormal metabolism of lipids. • Hepatic autophagy regulates lipid metabolism as demonstrated by macrolipophagy in response to starvation and hepatic overabundance of TG in obesity. • Autophagic signals are closely associated with apoptotic pathways. There is distinctive relationship between hepatic autophagy and apoptosis, which affects the progression of fatty liver. • Regulation of autophagic process can be a novel therapeutic strategy for fatty liver disease.
Collapse
|
12
|
Liver-Specific Deletion of Phosphatase and Tensin Homolog Deleted on Chromosome 10 Significantly Ameliorates Chronic EtOH-Induced Increases in Hepatocellular Damage. PLoS One 2016; 11:e0154152. [PMID: 27124661 PMCID: PMC4849752 DOI: 10.1371/journal.pone.0154152] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2015] [Accepted: 04/08/2016] [Indexed: 12/20/2022] Open
Abstract
Alcoholic liver disease is a significant contributor to global liver failure. In murine models, chronic ethanol consumption dysregulates PTEN/Akt signaling. Hepatospecific deletion of phosphatase and tensin homolog deleted on chromosome 10 (PTENLKO) mice possess constitutive activation of Akt(s) and increased de novo lipogenesis resulting in increased hepatocellular steatosis. This makes PTENLKO a viable model to examine the effects of ethanol in an environment of preexisting steatosis. The aim of this study was to determine the impact of chronic ethanol consumption and the absence of PTEN (PTENLKO) compared to Alb-Cre control mice (PTENf/f) on hepatocellular damage as evidenced by changes in lipid accumulation, protein carbonylation and alanine amino transferase (ALT). In the control PTENf/f animals, ethanol significantly increased ALT, liver triglycerides and steatosis. In contrast, chronic ethanol consumption in PTENLKO mice decreased hepatocellular damage when compared to PTENLKO pair-fed controls. Consumption of ethanol elevated protein carbonylation in PTENf/f animals but had no effect in PTENLKO animals. In PTENLKO mice, overall hepatic mRNA expression of genes that contribute to GSH homeostasis as well as reduced glutathione (GSH) and oxidized glutathione (GSSG) concentrations were significantly elevated compared to respective PTENf/f counterparts. These data indicate that during conditions of constitutive Akt activation and steatosis, increased GSH homeostasis assists in mitigation of ethanol-dependent induction of oxidative stress and hepatocellular damage. Furthermore, data herein suggest a divergence in EtOH-induced hepatocellular damage and increases in steatosis due to polyunsaturated fatty acids downstream of PTEN.
Collapse
|
13
|
de la Monte SM, Tong M, Agarwal AR, Cadenas E. Tobacco Smoke-Induced Hepatic Injury with Steatosis, Inflammation, and Impairments in Insulin and Insulin-Like Growth Factor Signaling. ACTA ACUST UNITED AC 2016; 6. [PMID: 27525191 PMCID: PMC4979551 DOI: 10.4172/2161-0681.1000269] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
Background Alcoholic liver disease (ALD) is associated with impairments in hepatic insulin and insulin-like growth factor (IGF) signaling through cell growth, survival, and metabolic pathways. Since not all heavy drinkers develop ALD, co-factors may be important. Epidemiologic data indicate that most heavy drinkers smoke tobacco and experimental data revealed that low-level nitrosamine exposures, including those from tobacco, can cause steatohepatitis with hepatic insulin/IGF resistance and exacerbate ALD. We hypothesize that cigarette smoke (CS) exposures also cause liver injury with impaired hepatic insulin/IGF signaling, and thereby contribute to ALD. Methods Adult male A/J mice were exposed to air for 8 weeks (A8), CS for 4 (CS4) or 8 (CS8) weeks, or CS for 8 weeks with 2 weeks recovery (CS8+R). Results CS exposures caused progressive liver injury with disruption of the normal hepatic chord architecture, lobular inflammation, apoptosis or necrosis, micro-steatosis, sinusoidal dilatation, and nuclear pleomorphism. Histopathological liver injury scores increased significantly from A8 to CS4 and then further to CS8 (P<0.0001). The mean histological grade was also higher in CS8+R relative to A8 (P<0.0001) but lower than in CS4, reflecting partial resolution of injury by CS withdrawal. CS exposures impaired insulin and IGF-1 signaling through IRS-1, Akt, GSK-3β, and PRAS40. Livers from CS8+R mice had normalized or elevated levels of insulin receptor, pYpY-Insulin-R, 312S-IRS-1, 473S-Akt, S9-GSK-3β, and pT246-PRAS40 relative to A8, CS4, or CS8, reflecting partial recovery. Conclusion CS-mediated liver injury and steatohepatitis with impairments in insulin/IGF signalling are reminiscent of the findings in ALD. Therefore, CS exposures (either first or second-hand) may serve as a co-factor in ALD. The persistence of several abnormalities following CS exposure cessation suggests that some aspects of CS-mediated hepatic metabolic dysfunction are not readily reversible.
Collapse
Affiliation(s)
- Suzanne M de la Monte
- Liver Research Center, Department of Medicine, Rhode Island Hospital and the Alpert Medical School of Brown University, USA; Division of Neuropathology and Departments of Pathology, Neurology, and Neurosurgery, Rhode Island Hospital and the Alpert Medical School of Brown University, USA
| | - M Tong
- Liver Research Center, Department of Medicine, Rhode Island Hospital and the Alpert Medical School of Brown University, USA
| | - A R Agarwal
- Department of Pharmacology and Pharmaceutical Sciences, School of Pharmacy, University of Southern California, Los Angeles, CA, USA
| | - E Cadenas
- Department of Pharmacology and Pharmaceutical Sciences, School of Pharmacy, University of Southern California, Los Angeles, CA, USA
| |
Collapse
|
14
|
Andreani T, Tong M, Gundogan F, Silbermann E, de la Monte SM. Differential Effects of 3rd Trimester-Equivalent Binge Ethanol and Tobacco-Specific Nitrosamine Ketone Exposures on Brain Insulin Signaling in Adolescence. JOURNAL OF DIABETES AND RELATED DISORDERS 2016; 1:105. [PMID: 29242853 PMCID: PMC5726776] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
Abstract
BACKGROUND Fetal alcohol spectrum disorder (FASD) is associated with impairments in insulin and insulin-like growth factor (IGF) signaling through Akt pathways and altered expression of neuro-glial proteins needed for structural and functional integrity of the brain. However, alcohol abuse correlates with smoking, and tobacco smoke contains 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone (NNK), which like other nitrosamines, impairs insulin and IGF signaling. HYPOTHESIS NNK exposure can serve as a co-factor in mediating long-term neuro-developmental abnormalities associated with FASD. DESIGN Long Evans rat pups were IP administered ethanol (2 g/kg) on postnatal days (P) 2, 4, 6 and/or NNK (2 mg/kg) on P3, P5, and P7, simulating third trimester human exposures. Temporal lobes from P30 rats (young adolescent) were used to measure signaling through the insulin/IGF-1/Akt pathways by multiplex ELISAs, and expression of neuroglial proteins by duplex ELISAs. RESULTS Ethanol, NNK, and ethanol + NNK exposures significantly inhibited insulin receptor tyrosine phosphorylation, and IRS-1 and myelin-associated glycoprotein expression. However, the major long-term adverse effects on Akt pathway downstream signaling and its targeted proteins including choline acetyltransferase, Tau, pTau, ubiquitin, and aspartate-β-hydroxylase were due to NNK rather than ethanol. CONCLUSION Alcohol and tobacco exposures can both contribute to long-term brain abnormalities currently regarded fetal ethanol effects. However, the findings suggest that many of the adverse effects on brain function are attributable to smoking, including impairments in signaling through survival and metabolic pathways, and altered expression of genes that regulate myelin synthesis, maturation and integrity and synaptic plasticity. Therefore, public health measures should address both substances of abuse to prevent "FASD".
Collapse
Affiliation(s)
- Tomas Andreani
- Department of Medicine, Division of Gastroenterology, and the Liver
Research Center Rhode Island Hospital, Providence, RI, USA
| | - Ming Tong
- Department of Medicine, Division of Gastroenterology, and the Liver
Research Center Rhode Island Hospital, Providence, RI, USA
- Warren Alpert Medical School of Brown University, Providence, RI,
USA
| | - Fusun Gundogan
- Department of Pathology, Women and Infants Hospital of Rhode Island,
Providence, RI, USA
- Warren Alpert Medical School of Brown University, Providence, RI,
USA
| | | | - Suzanne M. de la Monte
- Department of Medicine, Division of Gastroenterology, and the Liver
Research Center Rhode Island Hospital, Providence, RI, USA
- Departments of Pathology and Neurology, and the Division of
Neuropathology, Rhode Island Hospital, Providence, RI, USA
- Warren Alpert Medical School of Brown University, Providence, RI,
USA
| |
Collapse
|
15
|
Oxidative Stress and Inflammation in Hepatic Diseases: Therapeutic Possibilities of N-Acetylcysteine. Int J Mol Sci 2015; 16:30269-308. [PMID: 26694382 PMCID: PMC4691167 DOI: 10.3390/ijms161226225] [Citation(s) in RCA: 145] [Impact Index Per Article: 16.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2015] [Revised: 12/02/2015] [Accepted: 12/04/2015] [Indexed: 12/12/2022] Open
Abstract
Liver disease is highly prevalent in the world. Oxidative stress (OS) and inflammation are the most important pathogenetic events in liver diseases, regardless the different etiology and natural course. N-acetyl-l-cysteine (the active form) (NAC) is being studied in diseases characterized by increased OS or decreased glutathione (GSH) level. NAC acts mainly on the supply of cysteine for GSH synthesis. The objective of this review is to examine experimental and clinical studies that evaluate the antioxidant and anti-inflammatory roles of NAC in attenuating markers of inflammation and OS in hepatic damage. The results related to the supplementation of NAC in any form of administration and type of study are satisfactory in 85.5% (n = 59) of the cases evaluated (n = 69, 100%). Within this percentage, the dosage of NAC utilized in studies in vivo varied from 0.204 up to 2 g/kg/day. A standard experimental design of protection and treatment as well as the choice of the route of administration, with a broader evaluation of OS and inflammation markers in the serum or other biological matrixes, in animal models, are necessary. Clinical studies are urgently required, to have a clear view, so that, the professionals can be sure about the effectiveness and safety of NAC prescription.
Collapse
|
16
|
Yang L, Jin GH, Zhou JY. The Role of Ceramide in the Pathogenesis of Alcoholic Liver Disease. Alcohol Alcohol 2015; 51:251-7. [PMID: 26511776 DOI: 10.1093/alcalc/agv119] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2015] [Accepted: 09/22/2015] [Indexed: 02/06/2023] Open
Abstract
AIMS Ceramide is an important second messenger in the sphingomyelin signaling pathway. In this review, we will focus on the potential role of ceramide in the pathogenesis of alcoholic liver disease (ALD). METHODS We have summarized the relevant studies and reviews about the role of ceramide in ALD. In addition, we have discussed the role of acid sphingomyelinase and protein phosphatase 2A in ALD, which are associated with ceramide and hepatic steatosis. RESULTS Recent studies have proved that the immunoreactivity and content of ceramide were increased, both in experimental models of chronic alcohol-induced steatohepatitis and human livers with severe chronic alcohol-related liver disease. Consistent with that, the levels of protein phosphatase 2A and acid sphingomyelinase were increased. Of relevance, the phosphorylation of adenosine monophosphate-activated protein kinase (AMPK) was inhibited, which could block the fatty acid oxidation and promote its synthesis. CONCLUSIONS It was hypothesized that ethanol promoted ceramide accumulation and increased PP2A activity by activating ASMase, which may be an important mechanism in the inhibitory effect on AMPK phosphorylation and then contributed to the progression of steatosis. ASMase, a specific mechanism of ceramide generation, was proved to be a regulator of steatosis, fibrosis, lipotoxicity and endoplasmic reticulum stress.
Collapse
Affiliation(s)
- Liu Yang
- Department of Infectious disease, Third Hospital, Hebei Medical University, 139 ZiQiang Road, Shijiazhuang 050051, China
| | - Guo-Hua Jin
- Department of Infectious disease, Third Hospital, Hebei Medical University, 139 ZiQiang Road, Shijiazhuang 050051, China
| | - Jun-Ying Zhou
- Department of Infectious disease, Third Hospital, Hebei Medical University, 139 ZiQiang Road, Shijiazhuang 050051, China
| |
Collapse
|
17
|
Tong M, Yu R, Deochand C, de la Monte SM. Differential Contributions of Alcohol and the Nicotine-Derived Nitrosamine Ketone (NNK) to Insulin and Insulin-Like Growth Factor Resistance in the Adolescent Rat Brain. Alcohol Alcohol 2015; 50:670-9. [PMID: 26373814 DOI: 10.1093/alcalc/agv101] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2014] [Accepted: 08/17/2015] [Indexed: 12/11/2022] Open
Abstract
AIMS Since epidemiologic studies suggest that tobacco smoke toxins, e.g. the nicotine-derived nitrosamine ketone (NNK) tobacco-specific nitrosamine, can be a co-factor in alcohol-related brain disease (ARBD), we examined the independent and additive effects of alcohol and NNK exposures on spatial learning/memory, and brain insulin/IGF signaling, neuronal function and oxidative stress. METHODS Adolescent Long Evans rats were fed liquid diets containing 0 or 26% caloric ethanol for 8 weeks. During weeks 3-8, rats were treated with i.p. NNK (2 mg/kg, 3×/week) or saline. In weeks 7-8, ethanol groups were binge-administered ethanol (2 g/kg; 3×/week). In week 8, at 12 weeks of age, rats were subjected to Morris Water Maze tests. Temporal lobes were used to assess molecular indices of insulin/IGF resistance, oxidative stress and neuronal function. RESULTS Ethanol and NNK impaired spatial learning, and NNK ± ethanol impaired memory. Linear trend analysis demonstrated worsening performance from control to ethanol, to NNK, and then ethanol + NNK. Ethanol ± NNK, caused brain atrophy, inhibited insulin signaling through the insulin receptor and Akt, activated GSK-3β, increased protein carbonyl and 3-nitrotyrosine, and reduced acetylcholinesterase. NNK increased NTyr. Ethanol + NNK had synergistic stimulatory effects on 8-iso-PGF-2α, inhibitory effects on p-p70S6K, tau and p-tau and trend effects on insulin-like growth factor type 1 (IGF-1) receptor expression and phosphorylation. CONCLUSIONS Ethanol, NNK and combined ethanol + NNK exposures that begin in adolescence impair spatial learning and memory in young adults. The ethanol and/or NNK exposures differentially impair insulin/IGF signaling through neuronal growth, survival and plasticity pathways, increase cellular injury and oxidative stress and reduce expression of critical proteins needed for neuronal function.
Collapse
Affiliation(s)
- Ming Tong
- Department of Medicine, Division of Gastroenterology, and the Liver Research Center, Rhode Island Hospital, Providence, RI, USA Warren Alpert Medical School of Brown University, Providence, RI, USA
| | - Rosa Yu
- Departments of Pathology and Neurology, and the Division of Neuropathology, Rhode Island Hospital, Providence, RI, USA
| | - Chetram Deochand
- Biotechnology Graduate Program, Brown University, Providence, RI, USA
| | - Suzanne M de la Monte
- Department of Medicine, Division of Gastroenterology, and the Liver Research Center, Rhode Island Hospital, Providence, RI, USA Warren Alpert Medical School of Brown University, Providence, RI, USA Departments of Pathology and Neurology, and the Division of Neuropathology, Rhode Island Hospital, Providence, RI, USA
| |
Collapse
|
18
|
Caro AA, Bell M, Ejiofor S, Zurcher G, Petersen DR, Ronis MJJ. N-acetylcysteine inhibits the up-regulation of mitochondrial biogenesis genes in livers from rats fed ethanol chronically. Alcohol Clin Exp Res 2015; 38:2896-906. [PMID: 25581647 DOI: 10.1111/acer.12576] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2014] [Accepted: 09/06/2014] [Indexed: 12/18/2022]
Abstract
BACKGROUND Chronic ethanol (EtOH) administration to experimental animals induces hepatic oxidative stress and up-regulates mitochondrial biogenesis. The mechanisms by which chronic EtOH up-regulates mitochondrial biogenesis have not been fully explored. In this work, we hypothesized that oxidative stress is a factor that triggers mitochondrial biogenesis after chronic EtOH feeding. If our hypothesis is correct, co-administration of antioxidants should prevent up-regulation of mitochondrial biogenesis genes. METHODS Rats were fed an EtOH-containing diet intragastrically by total enteral nutrition for 150 days, in the absence or presence of the antioxidant N-acetylcysteine (NAC) at 1.7 g/kg/d; control rats were administered isocaloric diets where carbohydrates substituted for EtOH calories. RESULTS EtOH administration significantly increased hepatic oxidative stress, evidenced as decreased liver total glutathione and reduced glutathione/glutathione disulfide ratio. These effects were inhibited by co-administration of EtOH and NAC. Chronic EtOH increased the expression of mitochondrial biogenesis genes including peroxisome proliferator-activated receptor gamma-coactivator-1 alpha and mitochondrial transcription factor A, and mitochondrial DNA; co-administration of EtOH and NAC prevented these effects. Chronic EtOH administration was associated with decreased mitochondrial mass, inactivation and depletion of mitochondrial complex I and complex IV, and increased hepatic mitochondrial oxidative damage, effects that were not prevented by NAC. CONCLUSIONS These results suggest that oxidative stress caused by chronic EtOH triggered the up-regulation of mitochondrial biogenesis genes in rat liver, because an antioxidant such as NAC prevented both effects. Because NAC did not prevent liver mitochondrial oxidative damage, extra-mitochondrial effects of reactive oxygen species may regulate mitochondrial biogenesis. In spite of the induction of hepatic mitochondrial biogenesis genes by chronic EtOH, mitochondrial mass and function decreased probably in association with mitochondrial oxidative damage. These results also predict that the effectiveness of NAC as an antioxidant therapy for chronic alcoholism will be limited by its limited antioxidant effects in mitochondria, and its inhibitory effect on mitochondrial biogenesis.
Collapse
Affiliation(s)
- Andres A Caro
- Chemistry Department , Hendrix College, Conway, Arkansas
| | | | | | | | | | | |
Collapse
|
19
|
Ikura Y, Caldwell SH. Lipid droplet-associated proteins in alcoholic liver disease: a potential linkage with hepatocellular damage. INTERNATIONAL JOURNAL OF CLINICAL AND EXPERIMENTAL PATHOLOGY 2015; 8:8699-8708. [PMID: 26464614 PMCID: PMC4583846] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Subscribe] [Scholar Register] [Received: 06/28/2015] [Accepted: 07/29/2015] [Indexed: 06/05/2023]
Abstract
Steatosis is a characteristic morphological change of alcoholic liver disease, but its pathologic significance is still obscure. Regardless of cell types, intracellular lipid droplets are coated with a phospholipid monolayer, on which many kinds of lipid droplet-associated proteins are present. These proteins, such as the perilipin family of proteins and the cell death inducing DNA fragmentation factor (DFF) 45-like effectors, are recognized to play important roles in lipid metabolism in the physiological settings. In addition, recent lipidology studies have revealed that expression of the lipid droplet-associated proteins possibly participate in the pathologic processes of many metabolic disorders, including fatty liver and insulin resistance. Hence, controlling protein expressions is expected to offer novel therapeutic options. In this review, we summarize collected data concerning the potential contribution of the lipid droplet-associated proteins to the development of alcoholic fatty liver. Without exception, existing data indicates that the lipid droplet-associated proteins, especially the perilipin family proteins, are important factors in alcoholic fatty liver. These proteins exert a prosteatotic effect, and their expression is closely associated with lipotoxicity based on endoplasmic reticulum stress and oxidative injury. Although suppression of their expression may be beneficial, careful consideration is required because these proteins simultaneously function as protective factors against lipotoxicity.
Collapse
Affiliation(s)
- Yoshihiro Ikura
- Department of Pathology, Takatsuki General Hospital1-3-13, Kosobecho, Takatsuki 569-1192, Japan
| | - Stephen H Caldwell
- Division of Gastroenterology and Hepatology, University of VirginiaCharlottesville, Virginia 22908-0708, USA
| |
Collapse
|
20
|
Zabala V, Tong M, Yu R, Ramirez T, Yalcin EB, Balbo S, Silbermann E, Deochand C, Nunez K, Hecht S, de la Monte SM. Potential contributions of the tobacco nicotine-derived nitrosamine ketone (NNK) in the pathogenesis of steatohepatitis in a chronic plus binge rat model of alcoholic liver disease. Alcohol Alcohol 2015; 50:118-31. [PMID: 25618784 DOI: 10.1093/alcalc/agu083] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
AIMS Alcoholic liver disease (ALD) is linked to binge drinking and cigarette smoking. Heavy chronic ± binge alcohol, or low-level exposures to dietary nitrosamines cause steatohepatitis with insulin resistance and oxidative stress in animal models. This study examines hepatotoxic effects of sub-mutagenic exposures to tobacco-specific nitrosamine (NNK) in relation to ALD. METHODS Long Evans rats were fed liquid diets containing 0 or 26% (caloric) ethanol (EtOH) for 8 weeks. In Weeks 3 through 8, rats were treated with NNK (2 mg/kg) or saline by i.p. injection, 3×/week, and in Weeks 7 and 8, EtOH-fed rats were binge-administered 2 g/kg EtOH 3×/week; controls were given saline. RESULTS EtOH ± NNK caused steatohepatitis with necrosis, disruption of the hepatic cord architecture, ballooning degeneration, early fibrosis, mitochondrial cytopathy and ER disruption. Severity of lesions was highest in the EtOH+NNK group. EtOH and NNK inhibited insulin/IGF signaling through Akt and activated pro-inflammatory cytokines, while EtOH promoted lipid peroxidation, and NNK increased apoptosis. O(6)-methyl-Guanine adducts were only detected in NNK-exposed livers. CONCLUSION Both alcohol and NNK exposures contribute to ALD pathogenesis, including insulin/IGF resistance and inflammation. The differential effects of EtOH and NNK on adduct formation are critical to ALD progression among alcoholics who smoke.
Collapse
Affiliation(s)
- Valerie Zabala
- Department of Medicine, Division of Gastroenterology, and The Liver Research Center, Rhode Island Hospital, Providence, RI, USA Department of Molecular Pharmacology and Physiology, Brown University, Providence, RI, USA
| | - Ming Tong
- Department of Medicine, Division of Gastroenterology, and The Liver Research Center, Rhode Island Hospital, Providence, RI, USA Warren Alpert Medical School of Brown University, Providence, RI, USA
| | - Rosa Yu
- Department of Neuroscience, Brown University, Providence, RI, USA
| | - Teresa Ramirez
- Department of Molecular Pharmacology and Physiology, Brown University, Providence, RI, USA
| | - Emine B Yalcin
- Department of Medicine, Division of Gastroenterology, and The Liver Research Center, Rhode Island Hospital, Providence, RI, USA Warren Alpert Medical School of Brown University, Providence, RI, USA
| | - Silvia Balbo
- Masonic Cancer Center, University of Minnesota, Cancer and Cardiovascular Research Building, 2231 6th Street SE, Minneapolis, MN 55455, USA
| | | | - Chetram Deochand
- Biotechnology Graduate Program, Brown University, Providence, RI, USA
| | - Kavin Nunez
- Department of Neuroscience, Brown University, Providence, RI, USA
| | - Stephen Hecht
- Masonic Cancer Center, University of Minnesota, Cancer and Cardiovascular Research Building, 2231 6th Street SE, Minneapolis, MN 55455, USA
| | - Suzanne M de la Monte
- Department of Medicine, Division of Gastroenterology, and The Liver Research Center, Rhode Island Hospital, Providence, RI, USA Warren Alpert Medical School of Brown University, Providence, RI, USA Departments of Pathology and Neurology, and the Division of Neuropathology, Rhode Island Hospital, Providence, RI, USA
| |
Collapse
|
21
|
Correnti JM, Juskeviciute E, Swarup A, Hoek JB. Pharmacological ceramide reduction alleviates alcohol-induced steatosis and hepatomegaly in adiponectin knockout mice. Am J Physiol Gastrointest Liver Physiol 2014; 306:G959-73. [PMID: 24742988 PMCID: PMC4042116 DOI: 10.1152/ajpgi.00395.2013] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Hepatosteatosis, the ectopic accumulation of lipid in the liver, is one of the earliest clinical signs of alcoholic liver disease (ALD). Alcohol-dependent deregulation of liver ceramide levels as well as inhibition of AMP-activated protein kinase (AMPK) and peroxisome proliferator-activated receptor α (PPAR-α) activity are thought to contribute to hepatosteatosis development. Adiponectin can regulate lipid handling in the liver and has been shown to reduce ceramide levels and activate AMPK and PPAR-α. However, the mechanisms by which adiponectin prevents alcoholic hepatosteatosis remain incompletely characterized. To address this question, we assessed ALD progression in wild-type (WT) and adiponectin knockout (KO) mice fed an ethanol-containing liquid diet or isocaloric control diet. Adiponectin KO mice relative to WT had increased alcohol-induced hepatosteatosis and hepatomegaly, similar modest increases in serum alanine aminotransferase, and reduced liver TNF. Restoring circulating adiponectin levels using recombinant adiponectin ameliorated alcohol-induced hepatosteatosis and hepatomegaly in adiponectin KO mice. Alcohol-fed WT and adiponectin KO animals had equivalent reductions in AMPK protein and PPAR-α DNA binding activity compared with control-fed animals. No difference in P-AMPK/AMPK ratio was detected, suggesting that alcohol-dependent deregulation of AMPK and PPAR-α in the absence of adiponectin are not primary causes of the observed increase in hepatosteatosis in these animals. By contrast, alcohol treatment increased liver ceramide levels in adiponectin KO but not WT mice. Importantly, pharmacological inhibition of de novo ceramide synthesis in adiponectin KO mice abrogated alcohol-mediated increases in liver ceramides, steatosis, and hepatomegaly. These data suggest that adiponectin reduces alcohol-induced steatosis and hepatomegaly through regulation of liver ceramides, but its absence does not exacerbate alcohol-induced liver damage.
Collapse
Affiliation(s)
- Jason M. Correnti
- Department of Pathology, Anatomy, and Cell Biology, Thomas Jefferson University, Philadelphia, Pennsylvania
| | - Egle Juskeviciute
- Department of Pathology, Anatomy, and Cell Biology, Thomas Jefferson University, Philadelphia, Pennsylvania
| | - Aditi Swarup
- Department of Pathology, Anatomy, and Cell Biology, Thomas Jefferson University, Philadelphia, Pennsylvania
| | - Jan B. Hoek
- Department of Pathology, Anatomy, and Cell Biology, Thomas Jefferson University, Philadelphia, Pennsylvania
| |
Collapse
|
22
|
Shearn CT, Backos DS, Orlicky DJ, Smathers-McCullough RL, Petersen DR. Identification of 5' AMP-activated kinase as a target of reactive aldehydes during chronic ingestion of high concentrations of ethanol. J Biol Chem 2014; 289:15449-62. [PMID: 24722988 DOI: 10.1074/jbc.m113.543942] [Citation(s) in RCA: 47] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
The production of reactive aldehydes including 4-hydroxy-2-nonenal (4-HNE) is a key component of the pathogenesis in a spectrum of chronic inflammatory hepatic diseases including alcoholic liver disease (ALD). One consequence of ALD is increased oxidative stress and altered β-oxidation in hepatocytes. A major regulator of β-oxidation is 5' AMP protein kinase (AMPK). In an in vitro cellular model, we identified AMPK as a direct target of 4-HNE adduction resulting in inhibition of both H2O2 and 5-aminoimidazole-4-carboxyamide ribonucleoside (AICAR)-induced downstream signaling. By employing biotin hydrazide capture, it was confirmed that 4-HNE treatment of cells resulted in carbonylation of AMPKα/β, which was not observed in untreated cells. Using a murine model of alcoholic liver disease, treatment with high concentrations of ethanol resulted in an increase in phosphorylated as well as carbonylated AMPKα. Despite increased AMPK phosphorylation, there was no significant change in phosphorylation of acetyl CoA carboxylase. Mass spectrometry identified Michael addition adducts of 4-HNE on Cys(130), Cys(174), Cys(227), and Cys(304) on recombinant AMPKα and Cys(225) on recombinant AMPKβ. Molecular modeling analysis of identified 4-HNE adducts on AMPKα suggest that inhibition of AMPK occurs by steric hindrance of the active site pocket and by inhibition of hydrogen peroxide induced oxidation. The observed inhibition of AMPK by 4-HNE provides a novel mechanism for altered β-oxidation in ALD, and these data demonstrate for the first time that AMPK is subject to regulation by reactive aldehydes in vivo.
Collapse
Affiliation(s)
| | | | - David J Orlicky
- Department of Pathology, University of Colorado Denver-Anschutz Medical Campus, Aurora, Colorado 80045 and
| | | | | |
Collapse
|
23
|
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]
|
24
|
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]
|
25
|
Posa JK, Selvaraj S, Sangeetha KN, Baskaran SK, Lakshmi BS. p53 mediates impaired insulin signaling in 3T3-L1 adipocytes during hyperinsulinemia. Cell Biol Int 2014; 38:818-24. [PMID: 24604666 DOI: 10.1002/cbin.10275] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2013] [Accepted: 02/04/2014] [Indexed: 12/31/2022]
Abstract
Hyperinsulinemia is being implicated in the development of insulin resistance but remains poorly understood. The present study focuses on p53-mediated impaired insulin signaling by hyperinsulinemia in 3T3-L1 adipocytes. Hyperinsulinemia impairs insulin-stimulated glucose uptake and its cellular signaling in a dose- and time-dependent manner. An increased level of reactive oxygen species (ROS) and stress response signals were observed, and quenching of the ROS by an antioxidant N-acetylcysteine (NAC) did not revert impaired insulin sensitivity. The tumor suppressor p53 has emerged as a crucial factor in the metabolic adaptation of cancer cells under nutritional starvation and is being studied in the development of insulin resistance in adipocytes at physiological level. Interestingly, we observed hyperinsulinemia-enhanced p53 level in a time-dependent manner without exhibiting cytotoxicity. Transient knockdown of p53 partially improved insulin sensitivity revealing a novel link between p53 and insulin signaling in adipocytes. The findings suggest that hyperinsulinemia-induced p53 impairs insulin sensitivity in 3T3-L1 adipocytes.
Collapse
Affiliation(s)
- Jyothi Kumari Posa
- Tissue culture and Drug discovery Laboratory, Centre for Biotechnology, Anna University, Chennai, 25, India
| | | | | | | | | |
Collapse
|
26
|
Czaja AJ. Hepatic inflammation and progressive liver fibrosis in chronic liver disease. World J Gastroenterol 2014; 20:2515-32. [PMID: 24627588 PMCID: PMC3949261 DOI: 10.3748/wjg.v20.i10.2515] [Citation(s) in RCA: 242] [Impact Index Per Article: 24.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/27/2013] [Revised: 10/24/2013] [Accepted: 11/12/2013] [Indexed: 02/06/2023] Open
Abstract
Chronic liver inflammation drives hepatic fibrosis, and current immunosuppressive, anti-inflammatory, and anti-viral therapies can weaken this driver. Hepatic fibrosis is reversed, stabilized, or prevented in 57%-79% of patients by conventional treatment regimens, mainly by their anti-inflammatory actions. Responses, however, are commonly incomplete and inconsistently achieved. The fibrotic mechanisms associated with liver inflammation have been clarified, and anti-fibrotic agents promise to improve outcomes as adjunctive therapies. Hepatitis C virus and immune-mediated responses can activate hepatic stellate cells by increasing oxidative stress within hepatocytes. Angiotensin can be synthesized by activated hepatic stellate cells and promote the production of reactive oxygen species. Anti-oxidants (N-acetylcysteine, S-adenosyl-L-methionine, and vitamin E) and angiotensin inhibitors (losartin) have had anti-fibrotic actions in preliminary human studies, and they may emerge as supplemental therapies. Anti-fibrotic agents presage a new era of supplemental treatment for chronic liver disease.
Collapse
|
27
|
Shearn CT, Smathers RL, Backos DS, Reigan P, Orlicky DJ, Petersen DR. Increased carbonylation of the lipid phosphatase PTEN contributes to Akt2 activation in a murine model of early alcohol-induced steatosis. Free Radic Biol Med 2013; 65:680-692. [PMID: 23872024 PMCID: PMC3859727 DOI: 10.1016/j.freeradbiomed.2013.07.011] [Citation(s) in RCA: 246] [Impact Index Per Article: 22.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/01/2012] [Revised: 06/25/2013] [Accepted: 07/04/2013] [Indexed: 10/26/2022]
Abstract
The production of reactive aldehydes such as 4-hydroxynonenal (4-HNE) is a key event in the pathogenesis of alcoholic liver disease (ALD), which ranges from simple steatosis to fibrosis. The lipid phosphatase PTEN plays a central role in the regulation of lipid metabolism in the liver. In this study, the effects of chronic ethanol feeding and carbonylation on the PTEN signaling pathway were examined in a 9-week mouse feeding model for ALD. Chronic ethanol consumption resulted in altered redox homeostasis as evidenced by decreased GSH, decreased Trx1, and increased GST activity. Both PTEN expression and PTEN phosphorylation were significantly increased in the livers of ethanol-fed mice. Carbonylation of PTEN increased significantly in the ethanol-fed mice compared to pair-fed control animals, corresponding to decreased PTEN 3-phosphatase activity. Concomitantly, increased expression of Akt2 along with increased Akt phosphorylation at residues Thr(308), Thr(450), and Ser(473) was observed resulting in increased Akt2 activity in the ethanol-fed animals. Akt2 activation corresponded to a decrease in cytosolic SREBP and ChREBP. Subsequent LC/MS/MS analysis of 4-HNE-modified recombinant human PTEN identified Michael addition adducts of 4-HNE on Cys(71), Cys(136), Lys(147), Lys(223), Cys(250), Lys(254), Lys(313), Lys(327), and Lys(344). Computational-based molecular modeling analysis of 4-HNE adducted to Cys(71) near the active site and Lys(327) in the C2 domain of PTEN suggested inhibition of enzyme catalysis via either stearic hindrance of the active-site pocket or prevention of C2 domain-dependent PTEN function. We hypothesize that 4-HNE-mediated PTEN inhibition contributes to the observed activation of Akt2, suggesting a possible novel mechanism of lipid accumulation in response to increased reactive aldehyde production during chronic ethanol administration in mice.
Collapse
Affiliation(s)
- C T Shearn
- Department of Pharmaceutical Sciences, School of Pharmacy, University of Colorado at Denver, Anschutz Medical Campus, Aurora, CO 80045, USA
| | - R L Smathers
- Department of Pharmaceutical Sciences, School of Pharmacy, University of Colorado at Denver, Anschutz Medical Campus, Aurora, CO 80045, USA
| | - D S Backos
- Department of Pharmaceutical Sciences, School of Pharmacy, University of Colorado at Denver, Anschutz Medical Campus, Aurora, CO 80045, USA
| | - P Reigan
- Department of Pharmaceutical Sciences, School of Pharmacy, University of Colorado at Denver, Anschutz Medical Campus, Aurora, CO 80045, USA
| | - D J Orlicky
- Department of Pathology, School of Medicine, University of Colorado at Denver, Anschutz Medical Campus, Aurora, CO 80045, USA
| | - Dennis R Petersen
- Department of Pharmaceutical Sciences, School of Pharmacy, University of Colorado at Denver, Anschutz Medical Campus, Aurora, CO 80045, USA.
| |
Collapse
|
28
|
Cocoa flavonoids attenuate high glucose-induced insulin signalling blockade and modulate glucose uptake and production in human HepG2 cells. Food Chem Toxicol 2013; 64:10-9. [PMID: 24262486 DOI: 10.1016/j.fct.2013.11.014] [Citation(s) in RCA: 106] [Impact Index Per Article: 9.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2013] [Revised: 11/05/2013] [Accepted: 11/12/2013] [Indexed: 12/25/2022]
Abstract
Insulin resistance is the primary characteristic of type 2 diabetes. Cocoa and its main flavanol, (-)-epicatechin (EC), display some antidiabetic effects, but the mechanisms for their preventive activities related to glucose metabolism and insulin signalling in the liver remain largely unknown. In the present work, the preventive effect of EC and a cocoa polyphenolic extract (CPE) on insulin signalling and on both glucose production and uptake are studied in insulin-responsive human HepG2 cells treated with high glucose. Pre-treatment of cells with EC or CPE reverted decreased tyrosine-phosphorylated and total levels of IR, IRS-1 and -2 triggered by high glucose. EC and CPE pre-treatment also prevented the inactivation of the PI3K/AKT pathway and AMPK, as well as the diminution of GLUT-2 levels induced by high glucose. Furthermore, pre-treatment of cells with EC and CPE avoided the increase in PEPCK levels and the diminished glucose uptake provoked by high glucose, returning enhanced levels of glucose production and decreased glycogen content to control values. These findings suggest that EC and CPE improved insulin sensitivity of HepG2 treated with high glucose, preventing or delaying a potential hepatic dysfunction through the attenuation of the insulin signalling blockade and the modulation of glucose uptake and production.
Collapse
|
29
|
Tong M, Longato L, Ramirez T, Zabala V, Wands JR, de la Monte SM. Therapeutic reversal of chronic alcohol-related steatohepatitis with the ceramide inhibitor myriocin. Int J Exp Pathol 2013; 95:49-63. [PMID: 24456332 DOI: 10.1111/iep.12052] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2013] [Accepted: 08/18/2013] [Indexed: 12/13/2022] Open
Abstract
Alcohol-related liver disease (ALD) is associated with steatohepatitis and insulin resistance. Insulin resistance impairs growth and disrupts lipid metabolism in hepatocytes. Dysregulated lipid metabolism promotes ceramide accumulation and oxidative stress, leading to lipotoxic states that activate endoplasmic reticulum (ER) stress pathways and worsen inflammation and insulin resistance. In a rat model of chronic alcohol feeding, we characterized the effects of a ceramide inhibitor, myriocin, on the histopathological and ultrastructural features of steatohepatitis, and the biochemical and molecular indices of hepatic steatosis, insulin resistance and ER stress. Myriocin reduced the severity of alcohol-related steatohepatitis including the abundance and sizes of lipid droplets and mitochondria, inflammation and architectural disruption of the ER. In addition, myriocin-mediated reductions in hepatic lipid and ceramide levels were associated with constitutive enhancement of insulin signalling through the insulin receptor and IRS-2, reduced hepatic oxidative stress and modulation of ER stress signalling mechanisms. In conclusion, ceramide accumulation in liver mediates tissue injury, insulin resistance and lipotoxicity in ALD. Reducing hepatic ceramide levels can help restore the structural and functional integrity of the liver in chronic ALD due to amelioration of insulin resistance and ER stress. However, additional measures are needed to protect the liver from alcohol-induced necroinflammatory responses vis-à-vis continued alcohol abuse.
Collapse
Affiliation(s)
- Ming Tong
- Liver Research Center, Division of Gastroenterology, Department of Medicine, Rhode Island Hospital and the Warren Alpert Medical School of Brown University, Providence, RI, USA
| | | | | | | | | | | |
Collapse
|
30
|
Lizarazo D, Zabala V, Tong M, Longato L, de la Monte SM. Ceramide inhibitor myriocin restores insulin/insulin growth factor signaling for liver remodeling in experimental alcohol-related steatohepatitis. J Gastroenterol Hepatol 2013; 28:1660-8. [PMID: 23802886 PMCID: PMC4551508 DOI: 10.1111/jgh.12291] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 05/19/2013] [Indexed: 12/13/2022]
Abstract
BACKGROUND AND AIM Alcohol-related liver disease (ALD) is mediated in part by insulin resistance. Attendant dysregulation of lipid metabolism increases accumulation of hepatic ceramides that worsen insulin resistance and compromise the structural and functional integrity of the liver. Insulin and insulin growth factor (IGF) stimulate aspartyl-asparaginyl-β-hydroxylase (AAH), which promotes cell motility needed for structural maintenance and remodeling of the liver. AAH mediates its effects by activating Notch, and in ALD, insulin/IGF signaling, AAH, and Notch are inhibited. METHOD To test the hypothesis that in ALD, hepatic ceramide load contributes to impairments in insulin, AAH, and Notch signaling, control and chronic ethanol-fed adult Long-Evans rats were treated with myriocin, an inhibitor of serine palmitoyl transferase. Livers were used to assess steatohepatitis, insulin/IGF pathway activation, and expression of AAH-Notch signaling molecules. RESULTS Chronic ethanol-fed rats had steatohepatitis with increased ceramide levels; impairments in signaling through the insulin receptor, insulin receptor substrate, and Akt; and decreased expression of AAH, Notch, Jagged, Hairy-Enhancer of Split-1, hypoxia-inducible factor 1α, and proliferating cell nuclear antigen. Myriocin abrogated many of these adverse effects of ethanol, particularly hepatic ceramide accumulation, steatohepatitis, and impairments of insulin signaling through Akt, AAH, and Notch. CONCLUSIONS In ALD, the histopathology and impairments in insulin/IGF responsiveness can be substantially resolved by ceramide inhibitor treatments, even in the context of continued chronic ethanol exposure.
Collapse
Affiliation(s)
- Diana Lizarazo
- Liver Research Center, Division of Gastroenterology and Department of Medicine, Rhode Island Hospital and the Warren Alpert Medical School of Brown University, Providence, RI, USA
| | - Valerie Zabala
- Liver Research Center, Division of Gastroenterology and Department of Medicine, Rhode Island Hospital and the Warren Alpert Medical School of Brown University, Providence, RI, USA
| | - Ming Tong
- Liver Research Center, Division of Gastroenterology and Department of Medicine, Rhode Island Hospital and the Warren Alpert Medical School of Brown University, Providence, RI, USA
| | - Lisa Longato
- Liver Research Center, Division of Gastroenterology and Department of Medicine, Rhode Island Hospital and the Warren Alpert Medical School of Brown University, Providence, RI, USA
| | - Suzanne M. de la Monte
- Liver Research Center, Divisions of Gastroenterology and Neuropathology and Departments of Medicine, Pathology, Neurology, and Neurosurgery, Rhode Island Hospital and the Warren Alpert Medical School of Brown University, Providence, RI, USA
| |
Collapse
|
31
|
Ramirez T, Tong M, Chen WC, Nguyen QG, Wands JR, de la Monte SM. Chronic alcohol-induced hepatic insulin resistance and endoplasmic reticulum stress ameliorated by peroxisome-proliferator activated receptor-δ agonist treatment. J Gastroenterol Hepatol 2013; 28:179-87. [PMID: 22988930 PMCID: PMC4406771 DOI: 10.1111/j.1440-1746.2012.07256.x] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 08/10/2012] [Indexed: 12/13/2022]
Abstract
BACKGROUND AND AIM Chronic alcoholic liver disease is associated with hepatic insulin resistance, dysregulated lipid metabolism with increased toxic lipid (ceramide) accumulation, lipid peroxidation, and oxidative and endoplasmic reticulum (ER) stress. Peroxisome-proliferator activated receptor (PPAR) agonists are insulin sensitizers that can restore hepatic insulin responsiveness in both alcohol and non-alcohol-related steatohepatitis. Herein, we demonstrate that treatment with a PPAR-δ agonist enhances insulin signaling and reduces the severities of ER stress and ceramide accumulation in an experimental model of ethanol-induced steatohepatitis. METHODS Adult male Long Evans rats were pair fed with isocaloric liquid diets containing 0% or 37% ethanol (caloric) for 8 weeks. After 3 weeks on the diets, rats were treated with vehicle or PPAR-δ agonist twice weekly by i.p. injection. RESULTS Ethanol-fed rats developed steatohepatitis with inhibition of signaling through the insulin and insulin-like growth factor-1 receptors, and Akt activated pathways. Despite continued ethanol exposure, PPAR-δ agonist co-treatments increased Akt activation, reduced multiple molecular indices of ER stress and steatohepatitis. CONCLUSIONS These results suggest that PPAR-δ agonist rescue of chronic alcoholic liver disease is mediated by enhancement of insulin signaling through Akt/metabolic pathways that reduce lipotoxicity and ER stress.
Collapse
Affiliation(s)
- Teresa Ramirez
- Liver Research Center and Department of Medicine, Rhode Island Hospital and Warren Alpert Medical School of Brown University, Providence, Rhode Island 02903, USA
| | | | | | | | | | | |
Collapse
|
32
|
Elmadhun NY, Lassaletta AD, Chu LM, Bianchi C, Sellke FW. Vodka and wine consumption in a swine model of metabolic syndrome alters insulin signaling pathways in the liver and skeletal muscle. Surgery 2012; 152:414-22. [PMID: 22938901 DOI: 10.1016/j.surg.2012.06.014] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2012] [Accepted: 06/07/2012] [Indexed: 12/17/2022]
Abstract
BACKGROUND The purpose of this study was to examine the effects of alcohol in the context of metabolic syndrome on insulin signaling pathways in the liver and skeletal muscle. METHODS Twenty-six Yorkshire swine were fed a hypercaloric, high-fat diet for 4 weeks then split into 3 groups: hypercholesterolemic diet alone (HCC, n = 9), hypercholesterolemic diet with vodka (HCVOD, n = 9), and hypercholesterolemic diet with wine (HCW, n = 8) for 7 weeks. Animals underwent intravenous dextrose challenge before euthanasia and tissue collection. RESULTS HCC, HCVOD, and HCW groups had similar blood fasting glucose levels, liver function test, and body mass index. Thirty and 60 minutes after dextrose infusion, HCVOD and HCW groups had significantly increased blood glucose levels compared with the HCC group. The HCW group had significantly increased levels of insulin compared with the HCC group. Immunoblotting in skeletal muscle demonstrated that alcohol up-regulates p-IRS1, IRS2, AKT, AMPKα, PPARα, Fox01, and GLUT4. In the liver, HCW had up-regulation of AKT, AMPKα, and GLUT4 compared with HCC. Skeletal muscle immunohistochemistry demonstrated increased sarcolemmal expression of GLUT4 in both alcohol groups compared with HCC. CONCLUSION Moderate alcohol consumption in a swine model of metabolic syndrome worsens glucose metabolism by altering activation of the insulin signaling pathway in the liver and skeletal muscle.
Collapse
Affiliation(s)
- Nassrene Y Elmadhun
- Division of Cardiothoracic Surgery, Cardiovascular Research Center, Warren Alpert Medical School of Brown University, Providence, RI 02905, USA
| | | | | | | | | |
Collapse
|
33
|
Ramirez T, Longato L, Dostalek M, Tong M, Wands JR, de la Monte SM. Insulin resistance, ceramide accumulation and endoplasmic reticulum stress in experimental chronic alcohol-induced steatohepatitis. Alcohol Alcohol 2012; 48:39-52. [PMID: 22997409 DOI: 10.1093/alcalc/ags106] [Citation(s) in RCA: 62] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
AIMS Chronic alcohol abuse causes steatohepatitis with insulin resistance, which impairs hepatocellular growth, survival and metabolism. However, growing evidence supports the concept that progressive alcohol-related liver injury may be mediated by concurrent mal-signaling through other networks that promote insulin resistance, e.g. pro-inflammatory, pro-ceramide and endoplasmic reticulum (ER) stress cascades. METHODS Using the Long Evans rat model of chronic ethanol feeding, we characterized the histopathologic and ultrastructural features of steatohepatitis in relation to biochemical and molecular indices of tissue injury, inflammation, insulin resistance, dysregulated lipid metabolism and ER stress. RESULTS Chronic steatohepatitis with early chicken-wire fibrosis was associated with enlargement of mitochondria and disruption of ER structure by electron microscopy, elevated indices of lipid storage, lipid peroxidation and DNA damage, increased activation of pro-inflammatory cytokines, impaired signaling through the insulin receptor (InR), InR substrate-1, Akt, ribosomal protein S6 kinase and proline-rich Akt substrate 40 kDa, glycogen synthase kinase 3β activation and constitutive up-regulation of ceramide and ER stress-related genes. Liquid chromatography coupled with tandem mass spectrometry demonstrated altered ceramide profiles with higher levels of C14 and C18, and reduced C16 species in ethanol-exposed livers. CONCLUSION The histopathologic and ultrastructural abnormalities in chronic alcohol-related steatohepatitis are associated with persistent hepatic insulin resistance and pro-inflammatory cytokine activation, dysregulated lipid metabolism with altered ceramide profiles and both ER and oxidative stress. Corresponding increases in lipid peroxidation, DNA damage and protein carbonylation may have contributed to the chronicity and progression of disease. The findings herein suggest that multi-pronged therapeutic strategies may be needed for effective treatment of chronic alcoholic liver disease in humans.
Collapse
Affiliation(s)
- Teresa Ramirez
- Liver Research Center, Divisions of Gastroenterology and Neuropathology, Departments of Medicine, Rhode Island Hospital and Warren Alpert Medical School of Brown University, Claverick Street, Providence, RI 02903, USA
| | | | | | | | | | | |
Collapse
|
34
|
De La Monte SM. Metabolic derangements mediate cognitive impairment and Alzheimer's disease: role of peripheral insulin-resistance diseases. Panminerva Med 2012; 54:171-8. [PMID: 22801434 PMCID: PMC4537701] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/01/2023]
Abstract
Herein, we review evidence that systemic insulin-resistance diseases linked to obesity, type 2 diabetes, and non-alcoholic steatohepatitis promote neurodegeneration. Insulin-resistance dysregulates lipid metabolism, which promotes ceramide accumulation with attendant inflammation and endoplasmic reticulum (ER) stress. Mechanistically, we propose that toxic ceramides generated in extra-CNS tissues, e.g. liver, get released into peripheral blood, and subsequently transit across the blood-brain barrier into the brain where they induce brain insulin-resistance, inflammation, and cell death (extrinsic pathway). These abnormalities establish or help propagate a cascade of neurodegeneration associated with increased ER stress and ceramide generation, which exacerbate brain insulin-resistance, cell death, myelin degeneration, and neuro-inflammation. The data suggest that a mal-signaling network mediated by toxic ceramides, ER stress, and insulin-resistance should be targeted to disrupt positive feedback loops that drive the AD neurodegeneration cascade.
Collapse
Affiliation(s)
- S M De La Monte
- Department of Neuropathology, Rhode Island Hospital and the Warren Alpert Medical School of Brown University, Providence, RI, USA.
| |
Collapse
|
35
|
Impaired insulin/IGF signaling in experimental alcohol-related myopathy. Nutrients 2012; 4:1058-75. [PMID: 23016132 PMCID: PMC3448087 DOI: 10.3390/nu4081058] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2012] [Revised: 08/07/2012] [Accepted: 08/13/2012] [Indexed: 12/13/2022] Open
Abstract
Alcohol-related myopathy (Alc-M) is highly prevalent among heavy drinkers, although its pathogenesis is not well understood. We hypothesize that Alc-M is mediated by combined effects of insulin/IGF resistance and oxidative stress, similar to the effects of ethanol on liver and brain. We tested this hypothesis using an established model in which adult rats were pair-fed for 8 weeks with isocaloric diets containing 0% (N = 8) or 35.5% (N = 13) ethanol by caloric content. Gastrocnemius muscles were examined by histology, morphometrics, qRT-PCR analysis, and ELISAs. Chronic ethanol feeding reduced myofiber size and mRNA expression of IGF-1 polypeptide, insulin, IGF-1, and IGF-2 receptors, IRS-1, and IRS-2. Multiplex ELISAs demonstrated ethanol-associated inhibition of insulin, IRS-1, Akt, and p70S6K signaling, and increased activation of GSK-3β. In addition, ethanol-exposed muscles had increased 4-hydroxy-2-nonenal immunoreactivity, reflecting lipid peroxidation, and reduced levels of mitochondrial Complex IV, Complex V, and acetylcholinesterase. These results demonstrate that experimental Alc-M is associated with inhibition of insulin/IGF/IRS and downstream signaling that mediates metabolism and cell survival, similar to findings in alcoholic liver and brain degeneration. Moreover, the increased oxidative stress, which could be mediated by mitochondrial dysfunction, may have led to inhibition of acetylcholinesterase, which itself is sufficient to cause myofiber atrophy and degeneration.
Collapse
|
36
|
Advances in the current treatment of autoimmune hepatitis. Dig Dis Sci 2012; 57:1996-2010. [PMID: 22476586 DOI: 10.1007/s10620-012-2151-2] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/23/2011] [Accepted: 03/16/2012] [Indexed: 12/17/2022]
Abstract
Current treatment strategies for autoimmune hepatitis are complicated by frequent relapse after drug withdrawal, medication intolerance, and refractory disease. The objective of this review is to describe advances that have improved treatment outcomes by defining the optimum objectives of initial therapy, managing relapse more effectively, identifying problematic patients early, and incorporating the new pharmacological interventions that have emerged as frontline and salvage therapies. Initial corticosteroid treatment should be continued until serum aminotransferase, γ-globulin, and immunoglobulin G levels are normal, and maintenance of this improvement for 3-8 months before liver tissue assessment. Improvement to normal liver tissue is the ideal histological result that justifies drug withdrawal, but it is achievable in only 22 % of patients. Minimum portal hepatitis, inactive cirrhosis, or minimally active cirrhosis is the most common treatment end point. Relapse after drug withdrawal warrants institution of a long-term maintenance regimen, preferably with azathioprine. Mathematical models can identify problematic adult patients early, as also can clinical phenotype (age ≤ 30 years and HLA DRB1 03), rapidity of treatment response (≤ 24 months), presence of antibodies to soluble liver antigen, and non-white ethnicity. The calcineurin inhibitors (cyclosporine and tacrolimus) can be effective in steroid-refractory disease; mycophenolate mofetil can be corticosteroid-sparing and effective for azathioprine intolerance; budesonide combined with azathioprine can be effective for treatment-naïve, non-cirrhotic patients. Standard treatment regimens for autoimmune hepatitis can be upgraded without adjustments that require major new expertise.
Collapse
|
37
|
Insulin resistance, ceramide accumulation, and endoplasmic reticulum stress in human chronic alcohol-related liver disease. OXIDATIVE MEDICINE AND CELLULAR LONGEVITY 2012; 2012:479348. [PMID: 22577490 PMCID: PMC3347750 DOI: 10.1155/2012/479348] [Citation(s) in RCA: 92] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/15/2011] [Revised: 12/28/2011] [Accepted: 01/10/2012] [Indexed: 12/14/2022]
Abstract
Background. Chronic alcohol-related liver disease (ALD) is mediated by insulin resistance, mitochondrial dysfunction, inflammation, oxidative stress, and DNA damage. Recent studies suggest that dysregulated lipid metabolism with accumulation of ceramides, together with ER stress potentiate hepatic insulin resistance and may cause steatohepatitis to progress. Objective. We examined the degree to which hepatic insulin resistance in advanced human ALD is correlated with ER stress, dysregulated lipid metabolism, and ceramide accumulation. Methods. We assessed the integrity of insulin signaling through the Akt pathway and measured proceramide and ER stress gene expression, ER stress signaling proteins, and ceramide profiles in liver tissue. Results. Chronic ALD was associated with increased expression of insulin, IGF-1, and IGF-2 receptors, impaired signaling through IGF-1R and IRS1, increased expression of multiple proceramide and ER stress genes and proteins, and higher levels of the C14, C16, C18, and C20 ceramide species relative to control. Conclusions. In human chronic ALD, persistent hepatic insulin resistance is associated with dysregulated lipid metabolism, ceramide accumulation, and striking upregulation of multiple ER stress signaling molecules. Given the role of ceramides as mediators of ER stress and insulin resistance, treatment with ceramide enzyme inhibitors may help reverse or halt progression of chronic ALD.
Collapse
|
38
|
Ramirez T, Tong M, Ayala CA, Monfils PR, McMillan PN, Zabala V, Wands JR, de la Monte SM. Structural Correlates of PPAR Agonist Rescue of Experimental Chronic Alcohol-Induced Steatohepatitis. ACTA ACUST UNITED AC 2012; 2. [PMID: 26339530 PMCID: PMC4554760 DOI: 10.4172/2161-0681.1000114] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
Chronic alcoholic liver disease is associated with hepatic insulin resistance, inflammation, oxidative and ER stress, mitochondrial dysfunction, and DNA damage. Peroxisome-proliferator activated receptor (PPAR) agonists are insulin sensitizers that have anti-inflammatory/anti-oxidant effects. We previously showed that PPAR agonists can restore hepatic insulin responsiveness in chronic ethanol-fed rats with steatohepatitis. Herein, we furthered our investigations by characterizing the histological and ultrastructural changes mediated by PPAR agonist rescue of alcohol-induced steatohepatitis. Adult male Long Evans rats were pair fed with isocaloric liquid diets containing 0% or 37% ethanol (caloric) for 8 weeks. After 3 weeks on the diets, rats were treated with vehicle, or a PPAR-α, PPAR-δ, or PPAR-γ agonist twice weekly by i.p. injection. Ethanol-fed rats developed steatohepatitis with disordered hepatic chord architecture, mega-mitochondria, disruption of the RER, increased apoptosis, and increased 4-hydroxynonenal (HNE) and 3-nitrotyrosine (NTyr) immunoreactivity. PPAR-δ and PPAR-γ agonists reduced the severity of steatohepatitis, and restored the hepatic chord-like architectural, mitochondrial morphology, and RER organization, and the PPAR-δ agonist significantly reduced hepatic HNE. On the other hand, prominent RER tubule dilation, which could reflect ER stress, persisted in ethanol-exposed, PPAR-γ treated but not PPAR-δ treated livers. The PPAR-α agonist exacerbated both steatohepatitis and formation of mega-mitochondria, and it failed to restore RER architecture or lower biochemical indices of oxidative stress. In conclusion, improved hepatic insulin responsiveness and decreased inflammation resulting from PPAR-δ or PPAR-γ agonist treatments of alcohol-induced steatohepatitis are likely mediated by enhanced signaling through metabolic pathways with attendant reductions in ER stress, oxidative stress, and mitochondrial dysfunction.
Collapse
Affiliation(s)
- Teresa Ramirez
- Liver Research Center and Departments of Medicine, Pathology, Neurology, and Neurosurgery, Rhode Island Hospital and The Warren Alpert Medical School of Brown University, Providence, RI, USA
| | - Ming Tong
- Liver Research Center and Departments of Medicine, Pathology, Neurology, and Neurosurgery, Rhode Island Hospital and The Warren Alpert Medical School of Brown University, Providence, RI, USA
| | - Carol A Ayala
- Liver Research Center and Departments of Medicine, Pathology, Neurology, and Neurosurgery, Rhode Island Hospital and The Warren Alpert Medical School of Brown University, Providence, RI, USA
| | - Paul R Monfils
- Liver Research Center and Departments of Medicine, Pathology, Neurology, and Neurosurgery, Rhode Island Hospital and The Warren Alpert Medical School of Brown University, Providence, RI, USA
| | - Paul N McMillan
- Liver Research Center and Departments of Medicine, Pathology, Neurology, and Neurosurgery, Rhode Island Hospital and The Warren Alpert Medical School of Brown University, Providence, RI, USA
| | - Valerie Zabala
- Liver Research Center and Departments of Medicine, Pathology, Neurology, and Neurosurgery, Rhode Island Hospital and The Warren Alpert Medical School of Brown University, Providence, RI, USA
| | - Jack R Wands
- Liver Research Center and Departments of Medicine, Pathology, Neurology, and Neurosurgery, Rhode Island Hospital and The Warren Alpert Medical School of Brown University, Providence, RI, USA
| | - Suzanne M de la Monte
- Liver Research Center and Departments of Medicine, Pathology, Neurology, and Neurosurgery, Rhode Island Hospital and The Warren Alpert Medical School of Brown University, Providence, RI, USA
| |
Collapse
|
39
|
de la Monte SM. Triangulated mal-signaling in Alzheimer's disease: roles of neurotoxic ceramides, ER stress, and insulin resistance reviewed. J Alzheimers Dis 2012; 30 Suppl 2:S231-49. [PMID: 22337830 PMCID: PMC4550324 DOI: 10.3233/jad-2012-111727] [Citation(s) in RCA: 71] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
Ceramides are lipid signaling molecules that cause cytotoxicity and cell death mediated by insulin resistance, inflammation, and endoplasmic reticulum (ER) stress. However, insulin resistance dysregulates lipid metabolism, which promotes ceramide accumulation with attendant inflammation and ER stress. Herein, we discuss two major pathways, extrinsic and intrinsic, that converge and often overlap in propagating AD-type neurodegeneration via a triangulated mal-signaling network. First, we review evidence that systemic insulin resistance diseases linked to obesity, type 2 diabetes, and non-alcoholic steatohepatitis promote neurodegeneration. Mechanistically, we propose that toxic ceramides generated in extra-CNS tissues (e.g., liver) get released into peripheral blood, and subsequently transit across the blood-brain barrier into the brain where they induce brain insulin resistance, inflammation, and cell death (extrinsic pathway). Then we discuss the role of the intrinsic pathway of neurodegeneration which is mediated by endogenous or primary brain insulin/IGF resistance, and impairs neuronal and oligodendrocyte survival, energy metabolism, membrane integrity, cytoskeletal function, and AβPP-Aβ secretion. The end result is increased ER stress and ceramide generation, which exacerbate brain insulin resistance, cell death, myelin degeneration, and neuroinflammation. Altogether, the data suggest that the triangulated mal-signaling network mediated by toxic ceramides, ER stress, and insulin resistance should be targeted to disrupt positive feedback loops that drive the AD neurodegeneration cascade.
Collapse
Affiliation(s)
- Suzanne M de la Monte
- Department of Pathology (Neuropathology), Rhode Island Hospital and The Warren Alpert Medical School of Brown University, Providence, RI, USA. SuzanneDeLaMonte
| |
Collapse
|