Multi-Organ Alcohol-Related Damage: Mechanisms and Treatment

A topical collection in Biomolecules (ISSN 2218-273X). This collection belongs to the section "Molecular Medicine".

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Editors

Department of Internal Medicine, University of Nebraska Medical Center, Veteran Affairs Medical Center, 4101 Woolworth Ave, R151, Omaha, NE 68105-8080, USA
Interests: hepatitis C, B, HIV and other viral hepatitis; alcoholic liver disease; innate immunity; antigen presentation; proteasome; protein posttranslational modifications; animal models for hepatitis study
Special Issues, Collections and Topics in MDPI journals
Department of Internal Medicine, University of Nebraska Medical Center, Omaha, NE 68105, USA
Interests: alcoholic liver disease; protein methylation; gut-liver axis in alcoholic liver disease; non-alcoholic steatohepatitis
Special Issues, Collections and Topics in MDPI journals

Topical Collection Information

Dear Colleagues,

Alcohol consumption causes damage to various organs and systems. Liver is a primary target for the detrimental effects of alcohol since this substance of abuse is mainly metabolized by liver cells which express high levels of two major alcohol oxiding enzymes, alcohol dehydrogenase and CYP2E1. However, other organs, including brain, gut, pancreas, lungs, immune system are also affected by alcohol. Alcohol may also serve as a second hit for progression of viral infections, autoimmune diseases and cancer. Common mechanisms of alcohol-related organ injury include increases in oxidative stress, methylation impairments, posttranslational modifications of proteins, dysregulation of lipid metabolism and signal transduction pathways that ultimately affect cell survival and function. This Topical Collection will cover the pathobiology of alcohol-sensitive organ injury and the development of targeted treatment strategies.

We encourage you to share your data and thoughts in this broad field that clearly demonstrates how the harmful effects of alcohol contribute to disease initiation and progression in the liver, brain, gut, heart, lungs, and other organs and tissues of the body.

Prof. Dr. Natalia Osna
Prof. Dr. Kusum Kharbanda
Collection Editors

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Keywords

  • alcoholic liver disease (ALD)
  • steatohepatitis
  • fibrosis
  • cirhosis
  • parenhymal and non-parenhymal liver cells
  • brain
  • gut
  • lungs
  • immune responses
  • oxidative stress
  • methylation
  • viral infections
  • post-translational protein modifications
  • treatment of ALD

Published Papers (49 papers)

2022

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12 pages, 1784 KiB  
Article
Chronic Binge Alcohol and Ovarian Hormone Loss Dysregulate Circulating Immune Cell SIV Co-Receptor Expression and Mitochondrial Homeostasis in SIV-Infected Rhesus Macaques
by Patrick M. McTernan, Robert W. Siggins, Anna Catinis, Angela M. Amedee, Liz Simon and Patricia E. Molina
Biomolecules 2022, 12(7), 946; https://doi.org/10.3390/biom12070946 - 05 Jul 2022
Viewed by 1591
Abstract
Effective antiretroviral therapy (ART) has transitioned HIV to a chronic disease, with more than 50% of people living with HIV (PLWH) being over the age of 50. HIV targets activated CD4+ T cells expressing HIV-specific co-receptors (CCR5 and CXCR4). Previously, we reported [...] Read more.
Effective antiretroviral therapy (ART) has transitioned HIV to a chronic disease, with more than 50% of people living with HIV (PLWH) being over the age of 50. HIV targets activated CD4+ T cells expressing HIV-specific co-receptors (CCR5 and CXCR4). Previously, we reported that chronic binge alcohol (CBA)-administered male rhesus macaques had a higher percentage of gut CD4+ T cells expressing simian immunodeficiency virus (SIV) co-receptor CXCR4. Evidence also suggests that gonadal hormone loss increased activated peripheral T cells. Further, mitochondrial function is critical for HIV replication and alcohol dysregulates mitochondrial homeostasis. Hence, we tested the hypothesis that CBA and ovariectomy (OVX) increase circulating activated CD4+ T cells expressing SIV co-receptors and dysregulate mitochondrial homeostasis in SIV-infected female rhesus macaques. Results showed that at the study end-point, CBA/SHAM animals had increased peripheral CD4+ T cell SIV co-receptor expression, and a lower CD4+ T cell count compared to CBA/OVX animals. CBA and OVX animals had altered peripheral immune cell gene expression important for maintaining mitochondrial homeostasis. These results provide insights into how at-risk alcohol use could potentially impact viral expression in cellular reservoirs, particularly in SIV-infected ovariectomized rhesus macaques. Full article
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13 pages, 1556 KiB  
Article
Aldehyde Trapping by ADX-102 Is Protective against Cigarette Smoke and Alcohol Mediated Lung Cell Injury
by Carmen A. Ochoa, Claire G. Nissen, Deanna D. Mosley, Christopher D. Bauer, Destiny L. Jordan, Kristina L. Bailey and Todd A. Wyatt
Biomolecules 2022, 12(3), 393; https://doi.org/10.3390/biom12030393 - 02 Mar 2022
Cited by 2 | Viewed by 2520
Abstract
Most individuals diagnosed with alcohol use disorders smoke cigarettes. Large concentrations of malondialdehyde and acetaldehyde are found in lungs co-exposed to cigarette smoke and alcohol. Aldehydes directly injure lungs and form aldehyde protein adducts, impacting epithelial functions. Recently, 2-(3-Amino-6-chloroquinolin-2-yl)propan-2-ol (ADX-102) was developed as [...] Read more.
Most individuals diagnosed with alcohol use disorders smoke cigarettes. Large concentrations of malondialdehyde and acetaldehyde are found in lungs co-exposed to cigarette smoke and alcohol. Aldehydes directly injure lungs and form aldehyde protein adducts, impacting epithelial functions. Recently, 2-(3-Amino-6-chloroquinolin-2-yl)propan-2-ol (ADX-102) was developed as an aldehyde-trapping drug. We hypothesized that aldehyde-trapping compounds are protective against lung injury derived from cigarette smoke and alcohol co-exposure. To test this hypothesis, we pretreated mouse ciliated tracheal epithelial cells with 0–100 µM of ADX-102 followed by co-exposure to 5% cigarette smoke extract and 50 mM of ethanol. Pretreatment with ADX-102 dose-dependently protected against smoke and alcohol induced cilia-slowing, decreases in bronchial epithelial cell wound repair, decreases in epithelial monolayer resistance, and the formation of MAA adducts. ADX-102 concentrations up to 100 µM showed no cellular toxicity. As protein kinase C (PKC) activation is a known mechanism for slowing cilia and wound repair, we examined the effects of ADX-102 on smoke and alcohol induced PKC epsilon activity. ADX-102 prevented early (3 h) activation and late (24 h) autodownregulation of PKC epsilon in response to smoke and alcohol. These data suggest that reactive aldehydes generated from cigarette smoke and alcohol metabolism may be potential targets for therapeutic intervention to reduce lung injury. Full article
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2021

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8 pages, 389 KiB  
Article
Total Keratin-18 (M65) as a Potential, Early, Non-Invasive Biomarker of Hepatocyte Injury in Alcohol Intoxicated Adolescents—A Preliminary Study
by Katarzyna Zdanowicz, Witold Olanski, Monika Kowalczuk-Kryston, Anna Bobrus-Chociej, Irena Werpachowska and Dariusz Marek Lebensztejn
Biomolecules 2021, 11(6), 911; https://doi.org/10.3390/biom11060911 - 18 Jun 2021
Cited by 3 | Viewed by 1940
Abstract
Background: Underage drinking is associated with health risk behaviors. Serum keratin-18 (CK18) levels are increased in liver diseases and may be biomarkers of outcome. The purpose of this study was to determine if the total CK18 (M65) or caspase-cleaved CK18 (M30) levels were [...] Read more.
Background: Underage drinking is associated with health risk behaviors. Serum keratin-18 (CK18) levels are increased in liver diseases and may be biomarkers of outcome. The purpose of this study was to determine if the total CK18 (M65) or caspase-cleaved CK18 (M30) levels were different in adolescents admitted to hospital because of alcohol intoxication and controls with excluded liver diseases. Methods: A prospective study included 57 adolescents after alcohol use and 23 control subjects. The concentrations of M30 and M65 in the serum samples were evaluated using an enzyme-linked immunosorbent assay. Results: The median age was 15 (14–17) years and 49% were male. There were significant differences in M65 levels between the study and control groups (p = 0.03). The concentrations of M30 and M65 were insignificant in adolescents divided into subgroups according to blood alcohol concentrations (BAC). Significant positive correlations were found between BAC and M65 levels (p = 0.038; r = 0.3). In receiver operating characteristic (ROC) analysis M65 (cut-off = 125.966 IU/l, Se = 70.2%, Sp = 43.5%) allowed to differentiate between patients with and without alcohol intoxication (AUC = 0.66, p = 0.03). Conclusion: M65 appears to be a promising non-invasive biomarker of hepatocyte injury during alcohol intoxication in adolescents. Moreover, a higher concentration of M65 may indicate early organ injury before the increase in the activity of liver enzymes, alanine aminotransferase (ALT) and aspartate aminotransferase (AST). Full article
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2020

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21 pages, 1039 KiB  
Review
cAMP Signaling in Pathobiology of Alcohol Associated Liver Disease
by Mohamed Elnagdy, Shirish Barve, Craig McClain and Leila Gobejishvili
Biomolecules 2020, 10(10), 1433; https://doi.org/10.3390/biom10101433 - 11 Oct 2020
Cited by 16 | Viewed by 3818
Abstract
The importance of cyclic adenosine monophosphate (cAMP) in cellular responses to extracellular signals is well established. Many years after discovery, our understanding of the intricacy of cAMP signaling has improved dramatically. Multiple layers of regulation exist to ensure the specificity of cellular cAMP [...] Read more.
The importance of cyclic adenosine monophosphate (cAMP) in cellular responses to extracellular signals is well established. Many years after discovery, our understanding of the intricacy of cAMP signaling has improved dramatically. Multiple layers of regulation exist to ensure the specificity of cellular cAMP signaling. Hence, disturbances in cAMP homeostasis could arise at multiple levels, from changes in G protein coupled receptors and production of cAMP to the rate of degradation by phosphodiesterases. cAMP signaling plays critical roles in metabolism, inflammation and development of fibrosis in several tissues. Alcohol-associated liver disease (ALD) is a multifactorial condition ranging from a simple steatosis to steatohepatitis and fibrosis and ultimately cirrhosis, which might lead to hepatocellular cancer. To date, there is no FDA-approved therapy for ALD. Hence, identifying the targets for the treatment of ALD is an important undertaking. Several human studies have reported the changes in cAMP homeostasis in relation to alcohol use disorders. cAMP signaling has also been extensively studied in in vitro and in vivo models of ALD. This review focuses on the role of cAMP in the pathobiology of ALD with emphasis on the therapeutic potential of targeting cAMP signaling for the treatment of various stages of ALD. Full article
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15 pages, 451 KiB  
Review
Recent Advances in Understanding the Complexity of Alcohol-Induced Pancreatic Dysfunction and Pancreatitis Development
by Karuna Rasineni, Mukund P. Srinivasan, Appakalai N. Balamurugan, Bhupendra S. Kaphalia, Shaogui Wang, Wen-Xing Ding, Stephen J. Pandol, Aurelia Lugea, Liz Simon, Patricia E. Molina, Peter Gao, Carol A. Casey, Natalia A. Osna and Kusum K. Kharbanda
Biomolecules 2020, 10(5), 669; https://doi.org/10.3390/biom10050669 - 27 Apr 2020
Cited by 12 | Viewed by 7203
Abstract
Chronic excessive alcohol use is a well-recognized risk factor for pancreatic dysfunction and pancreatitis development. Evidence from in vivo and in vitro studies indicates that the detrimental effects of alcohol on the pancreas are from the direct toxic effects of metabolites and byproducts [...] Read more.
Chronic excessive alcohol use is a well-recognized risk factor for pancreatic dysfunction and pancreatitis development. Evidence from in vivo and in vitro studies indicates that the detrimental effects of alcohol on the pancreas are from the direct toxic effects of metabolites and byproducts of ethanol metabolism such as reactive oxygen species. Pancreatic dysfunction and pancreatitis development are now increasingly thought to be multifactorial conditions, where alcohol, genetics, lifestyle, and infectious agents may determine the initiation and course of the disease. In this review, we first highlight the role of nonoxidative ethanol metabolism in the generation and accumulation of fatty acid ethyl esters (FAEEs) that cause multi-organellar dysfunction in the pancreas which ultimately leads to pancreatitis development. Further, we discuss how alcohol-mediated altered autophagy leads to the development of pancreatitis. We also provide insights into how alcohol interactions with other co-morbidities such as smoking or viral infections may negatively affect exocrine and endocrine pancreatic function. Finally, we present potential strategies to ameliorate organellar dysfunction which could attenuate pancreatic dysfunction and pancreatitis severity. Full article
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14 pages, 3007 KiB  
Article
Chronic Alcohol Dysregulates Skeletal Muscle Myogenic Gene Expression after Hind Limb Immobilization in Female Rats
by Danielle E. Levitt, Alice Y. Yeh, Matthew J. Prendergast, Ronald G. Budnar, Jr., Katherine A. Adler, Garth Cook, Patricia E. Molina and Liz Simon
Biomolecules 2020, 10(3), 441; https://doi.org/10.3390/biom10030441 - 12 Mar 2020
Cited by 15 | Viewed by 3077
Abstract
Alcohol use and aging are risk factors for falls requiring immobilization and leading to skeletal muscle atrophy. Skeletal muscle regeneration is integral to post-immobilization recovery. This study aimed to elucidate the effects of alcohol and ovarian hormone loss on the expression of genes [...] Read more.
Alcohol use and aging are risk factors for falls requiring immobilization and leading to skeletal muscle atrophy. Skeletal muscle regeneration is integral to post-immobilization recovery. This study aimed to elucidate the effects of alcohol and ovarian hormone loss on the expression of genes implicated in muscle regeneration. Three-month-old female rats received an ovariectomy or a sham surgery, consumed an alcohol-containing or control diet for 10 weeks, were subjected to unilateral hind limb immobilization for seven days, and finally were allowed a three (3d)- or 14 (14d)-day recovery. Immobilization decreased the quadriceps weight at 3d and 14d, and alcohol decreased the quadriceps weight at 14d in the nonimmobilized hind limb (NI). At 3d, alcohol decreased gene expression of myoblast determination protein (MyoD) in the immobilized hind limb (IMM) and myocyte enhancer factor (Mef)2C and tumor necrosis factor (TNF)α in NI, and ovariectomy increased MyoD and decreased TNFα expression in NI. At 14d, alcohol increased the gene expression of Mef2C, MyoD, TNFα, and transforming growth factor (TFG)β in IMM and decreased monocyte chemoattractant protein (MCP)1 expression in NI; ovariectomy increased TNFα expression in NI, and alcohol and ovariectomy together increased Mef2C expression in NI. Despite increased TGFβ expression, there was no concomitant alcohol-mediated increase in collagen in IMM at 14d. Overall, these data indicate that alcohol dysregulated the post-immobilization alteration in the expression of genes implicated in regeneration. Whether alcohol-mediated molecular changes correspond with post-immobilization functional alterations remains to be determined. Full article
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2019

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19 pages, 4018 KiB  
Article
Alcohol Metabolism Potentiates HIV-Induced Hepatotoxicity: Contribution to End-Stage Liver Disease
by Murali Ganesan, Moses New-Aaron, Raghubendra Singh Dagur, Edward Makarov, Weimin Wang, Kusum K. Kharbanda, Srivatsan Kidambi, Larisa Y. Poluektova and Natalia A. Osna
Biomolecules 2019, 9(12), 851; https://doi.org/10.3390/biom9120851 - 10 Dec 2019
Cited by 24 | Viewed by 3705
Abstract
In an era of improved survival due to modern antiretroviral therapy, liver disease has become a major cause of morbidity and mortality, resulting in death in 15–17% of human immunodeficiency virus (HIV)-infected patients. Alcohol enhances HIV-mediated liver damage and promotes the progression to [...] Read more.
In an era of improved survival due to modern antiretroviral therapy, liver disease has become a major cause of morbidity and mortality, resulting in death in 15–17% of human immunodeficiency virus (HIV)-infected patients. Alcohol enhances HIV-mediated liver damage and promotes the progression to advanced fibrosis and cirrhosis. However, the mechanisms behind these events are uncertain. Here, we hypothesize that ethanol metabolism potentiates accumulation of HIV in hepatocytes, causing oxidative stress and intensive apoptotic cell death. Engulfment of HIV-containing apoptotic hepatocytes by non-parenchymal cells (NPCs) triggers their activation and liver injury progression. This study was performed on primary human hepatocytes and Huh7.5-CYP cells infected with HIV-1ADA, and major findings were confirmed by pilot data obtained on ethanol-fed HIV-injected chimeric mice with humanized livers. We demonstrated that ethanol exposure potentiates HIV accumulation in hepatocytes by suppressing HIV degradation by lysosomes and proteasomes. This leads to increased oxidative stress and hepatocyte apoptosis. Exposure of HIV-infected apoptotic hepatocytes to NPCs activates the inflammasome in macrophages and pro-fibrotic genes in hepatic stellate cells. We conclude that while HIV and ethanol metabolism-triggered apoptosis clears up HIV-infected hepatocytes, continued generation of HIV-expressing apoptotic bodies may be detrimental for progression of liver inflammation and fibrosis due to constant activation of NPCs. Full article
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19 pages, 1490 KiB  
Article
Ethanol Impairs NRF2/Antioxidant and Growth Signaling in the Intact Placenta In Vivo and in Human Trophoblasts
by Sambantham Shanmugam, Dhyanesh Patel, John M. Wolpert, Caezaan Keshvani, Xiaobo Liu, Susan E. Bergeson, Srivatsan Kidambi, Lenin Mahimainathan, George I. Henderson and Madhusudhanan Narasimhan
Biomolecules 2019, 9(11), 669; https://doi.org/10.3390/biom9110669 - 30 Oct 2019
Cited by 12 | Viewed by 3313
Abstract
NRF2 is a redox-sensitive transcription factor that depending on the duration or magnitude of the stress, either translocates to the nucleus (beneficial) or is degraded in the cytosol (harmful). However, the role of NRF2-based mechanism(s) under ethanol (E)-induced developmental toxicity in the placental [...] Read more.
NRF2 is a redox-sensitive transcription factor that depending on the duration or magnitude of the stress, either translocates to the nucleus (beneficial) or is degraded in the cytosol (harmful). However, the role of NRF2-based mechanism(s) under ethanol (E)-induced developmental toxicity in the placental context remains unknown. Here, we used a rat prenatal model of maternal alcohol stress consisting of intermittent ethanol vapor (IEV) daily from GD11 to GD20 with a 6 h ON/18 h OFF in a vapor chamber and in vitro placental model consisting of HTR-8 trophoblasts exposed to 86 mM of E for either 24 h or 48 h. The role of NRF2 was evaluated through the NRF2-transactivation reporter assay, qRT-PCR, and Western blotting for NRF2 and cell growth-promoting protein, and cell proliferation assay. In utero and in vitro E decreased the nuclear NRF2 content and diminished its transactivation ability along with dysregulation of the proliferation indices, PCNA, CYCLIN-D1, and p21. This was associated with a ~50% reduction in cell proliferation in vitro in trophoblasts. Interestingly, this was found to be partially rescued by ectopic Nrf2 overexpression. These results indicate that ethanol-induced dysregulation of NRF2 coordinately regulates PCNA/CYCLIN-D1/p21 involving growth network, at least partially to set a stage for placental perturbations. Full article
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17 pages, 6542 KiB  
Article
Linking Dysregulated AMPK Signaling and ER Stress in Ethanol-Induced Liver Injury in Hepatic Alcohol Dehydrogenase Deficient Deer Mice
by Mukund P. Srinivasan, Kamlesh K. Bhopale, Samir M. Amer, Jie Wan, Lata Kaphalia, Ghulam S. Ansari and Bhupendra S. Kaphalia
Biomolecules 2019, 9(10), 560; https://doi.org/10.3390/biom9100560 - 02 Oct 2019
Cited by 9 | Viewed by 3289
Abstract
Ethanol (EtOH) metabolism itself can be a predisposing factor for initiation of alcoholic liver disease (ALD). Therefore, a dose dependent study to evaluate liver injury was conducted in hepatic alcohol dehydrogenase (ADH) deficient (ADH) and ADH normal (ADH+) deer [...] Read more.
Ethanol (EtOH) metabolism itself can be a predisposing factor for initiation of alcoholic liver disease (ALD). Therefore, a dose dependent study to evaluate liver injury was conducted in hepatic alcohol dehydrogenase (ADH) deficient (ADH) and ADH normal (ADH+) deer mice fed 1%, 2% or 3.5% EtOH in the liquid diet daily for 2 months. Blood alcohol concentration (BAC), liver injury marker (alanine amino transferase (ALT)), hepatic lipids and cytochrome P450 2E1 (CYP2E1) activity were measured. Liver histology, endoplasmic reticulum (ER) stress, AMP-activated protein kinase (AMPK) signaling and cell death proteins were evaluated. Significantly increased BAC, plasma ALT, hepatic lipids and steatosis were found only in ADH deer mice fed 3.5% EtOH. Further, a significant ER stress and increased un-spliced X-box binding protein 1 were evident only in ADH deer mice fed 3.5% EtOH. Both strains fed 3.5% EtOH showed deactivation of AMPK, but increased acetyl Co-A carboxylase 1 and decreased carnitine palmitoyltransferase 1A favoring lipogenesis were found only in ADH deer mice fed 3.5% EtOH. Therefore, irrespective of CYP2E1 overexpression; EtOH dose and hepatic ADH deficiency contribute to EtOH-induced steatosis and liver injury, suggesting a linkage between ER stress, dysregulated hepatic lipid metabolism and AMPK signaling. Full article
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16 pages, 3521 KiB  
Article
Inhibition of Ghrelin Activity by Receptor Antagonist [d-Lys-3] GHRP-6 Attenuates Alcohol-Induced Hepatic Steatosis by Regulating Hepatic Lipid Metabolism
by Karuna Rasineni, Jacy L. Kubik, Carol A. Casey and Kusum K. Kharbanda
Biomolecules 2019, 9(10), 517; https://doi.org/10.3390/biom9100517 - 21 Sep 2019
Cited by 13 | Viewed by 5602
Abstract
Alcoholic steatosis, characterized by an accumulation of triglycerides in hepatocytes, is one of the earliest pathological changes in the progression of alcoholic liver disease. In our previous study, we showed that alcohol-induced increase in serum ghrelin levels impair insulin secretion from pancreatic β-cells. [...] Read more.
Alcoholic steatosis, characterized by an accumulation of triglycerides in hepatocytes, is one of the earliest pathological changes in the progression of alcoholic liver disease. In our previous study, we showed that alcohol-induced increase in serum ghrelin levels impair insulin secretion from pancreatic β-cells. The consequent reduction in the circulating insulin levels promote adipose-derived fatty acid mobilization to ultimately contribute to hepatic steatosis. In this study, we determined whether inhibition of ghrelin activity in chronic alcohol-fed rats could improve hepatic lipid homeostasis at the pancreas–adipose–liver axis. Adult Wistar rats were fed Lieber-DeCarli control or an ethanol liquid diet for 7 weeks. At 6 weeks, a subset of rats in each group were injected with either saline or ghrelin receptor antagonist, [d-Lys-3] GHRP-6 (DLys; 9 mg/kg body weight) for 5 days and all rats were sacrificed 2 days later. DLys treatment of ethanol rats improved pancreatic insulin secretion, normalized serum insulin levels, and the adipose lipid metabolism, as evidenced by the decreased serum free fatty acids (FFA). DLys treatment of ethanol rats also significantly decreased the circulating FFA uptake, de novo hepatic fatty acid synthesis ultimately attenuating alcoholic steatosis. To summarize, inhibition of ghrelin activity reduced alcoholic steatosis by improving insulin secretion, normalizing serum insulin levels, inhibiting adipose lipolysis, and preventing fatty acid uptake and synthesis in the liver. Our studies provided new insights on the important role of ghrelin in modulating the pancreas–adipose–liver, and promoting adipocyte lipolysis and hepatic steatosis. The findings offer a therapeutic approach of not only preventing alcoholic liver injury but also treating it. Full article
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2018

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15 pages, 391 KiB  
Review
Role of HIF-1α in Alcohol-Mediated Multiple Organ Dysfunction
by Niya L. Morris and Samantha M. Yeligar
Biomolecules 2018, 8(4), 170; https://doi.org/10.3390/biom8040170 - 10 Dec 2018
Cited by 18 | Viewed by 3925
Abstract
Excess alcohol consumption is a global crisis contributing to over 3 million alcohol-related deaths per year worldwide and economic costs exceeding $200 billion dollars, which include productivity losses, healthcare, and other effects (e.g., property damages). Both clinical and experimental models have shown that [...] Read more.
Excess alcohol consumption is a global crisis contributing to over 3 million alcohol-related deaths per year worldwide and economic costs exceeding $200 billion dollars, which include productivity losses, healthcare, and other effects (e.g., property damages). Both clinical and experimental models have shown that excessive alcohol consumption results in multiple organ injury. Although alcohol metabolism occurs primarily in the liver, alcohol exposure can lead to pathophysiological conditions in multiple organs and tissues, including the brain, lungs, adipose, liver, and intestines. Understanding the mechanisms by which alcohol-mediated organ dysfunction occurs could help to identify new therapeutic approaches to mitigate the detrimental effects of alcohol misuse. Hypoxia-inducible factor (HIF)-1 is a transcription factor comprised of HIF-1α and HIF-1β subunits that play a critical role in alcohol-mediated organ dysfunction. This review provides a comprehensive analysis of recent studies examining the relationship between HIF-1α and alcohol consumption as it relates to multiple organ injury and potential therapies to mitigate alcohol’s effects. Full article
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15 pages, 18015 KiB  
Article
Giantin Is Required for Post-Alcohol Recovery of Golgi in Liver Cells
by Carol A. Casey, Paul Thomes, Sonia Manca and Armen Petrosyan
Biomolecules 2018, 8(4), 150; https://doi.org/10.3390/biom8040150 - 16 Nov 2018
Cited by 12 | Viewed by 9149
Abstract
In hepatocytes and alcohol-metabolizing cultured cells, Golgi undergoes ethanol (EtOH)-induced disorganization. Perinuclear and organized Golgi is important in liver homeostasis, but how the Golgi remains intact is unknown. Work from our laboratories showed that EtOH-altered cellular function could be reversed after alcohol removal; [...] Read more.
In hepatocytes and alcohol-metabolizing cultured cells, Golgi undergoes ethanol (EtOH)-induced disorganization. Perinuclear and organized Golgi is important in liver homeostasis, but how the Golgi remains intact is unknown. Work from our laboratories showed that EtOH-altered cellular function could be reversed after alcohol removal; we wanted to determine whether this recovery would apply to Golgi. We used alcohol-metabolizing HepG2 (VA-13) cells (cultured with or without EtOH for 72 h) and rat hepatocytes (control and EtOH-fed (Lieber–DeCarli diet)). For recovery, EtOH was removed and replenished with control medium (48 h for VA-13 cells) or control diet (10 days for rats). Results: EtOH-induced Golgi disassembly was associated with de-dimerization of the largest Golgi matrix protein giantin, along with impaired transport of selected hepatic proteins. After recovery from EtOH, Golgi regained their compact structure, and alterations in giantin and protein transport were restored. In VA-13 cells, when we knocked down giantin, Rab6a GTPase or non-muscle myosin IIB, minimal changes were observed in control conditions, but post-EtOH recovery was impaired. Conclusions: These data provide a link between Golgi organization and plasma membrane protein expression and identify several proteins whose expression is important to maintain Golgi structure during the recovery phase after EtOH administration. Full article
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14 pages, 2980 KiB  
Article
Hepatitis C Virus-Infected Apoptotic Hepatocytes Program Macrophages and Hepatic Stellate Cells for Liver Inflammation and Fibrosis Development: Role of Ethanol as a Second Hit
by Murali Ganesan, Larisa Y. Poluektova, Chijioke Enweluzo, Kusum K. Kharbanda and Natalia A. Osna
Biomolecules 2018, 8(4), 113; https://doi.org/10.3390/biom8040113 - 13 Oct 2018
Cited by 15 | Viewed by 5778
Abstract
Hepatocyte apoptosis is a crucially important mechanism for liver disease pathogenesis, and the engulfment of apoptotic bodies (AB) by non-parenchymal cells serves as a leading mechanism of inflammation and fibrosis progression. Previously, we have shown that hepatitis C virus (HCV) and alcohol metabolites [...] Read more.
Hepatocyte apoptosis is a crucially important mechanism for liver disease pathogenesis, and the engulfment of apoptotic bodies (AB) by non-parenchymal cells serves as a leading mechanism of inflammation and fibrosis progression. Previously, we have shown that hepatitis C virus (HCV) and alcohol metabolites induce massive apoptosis in hepatocytes and the spread of HCV-infection to the neighboring uninfected cells. Here, we hypothesize that the capturing of AB by non-parenchymal cells, macrophages and hepatic stellate cells (HSC) changes their phenotype to promote inflammation and fibrosis. In this regard, we generated AB from Huh7.5CYP2E1 (RLW) cells also treated with an acetaldehyde-generating system (AGS) and incubated them with human monocyte-derived macrophages (MDMs) and HSC (LX2 cells). Activation of inflammasomes and pro-fibrotic markers has been tested by RT-PCR and linked to HCV expression and AGS-induced lipid peroxidation in RLW cells. After exposure to AB we observed activation of inflammasomes in MDMs, with a higher effect of AB HCV+, further enhanced by incubation of MDMs with ethanol. In HSC, activation of inflammasomes was modest; however, HCV and AGS exposure induced pro-fibrotic changes. We conclude that HCV as well as lipid peroxidation-adducted proteins packaged in AB may serve as a vehicle for delivery of parenchymal cell cargo to non-parenchymal cells to activate inflammasomes and pro-fibrotic genes and promote liver inflammation and fibrosis. Full article
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13 pages, 2785 KiB  
Meeting Report
Role of Nutrition in Alcoholic Liver Disease: Summary of the Symposium at the ESBRA 2017 Congress
by Kusum K. Kharbanda, Martin J. J. Ronis, Colin T. Shearn, Dennis R. Petersen, Samir Zakhari, Dennis R. Warner, Ariel E. Feldstein, Craig J. McClain and Irina A. Kirpich
Biomolecules 2018, 8(2), 16; https://doi.org/10.3390/biom8020016 - 26 Mar 2018
Cited by 12 | Viewed by 6049
Abstract
The symposium, “Role of Nutrition in Alcoholic Liver Disease”, was held at the European Society for Biomedical Research on Alcoholism Congress on 9 October 2017 in Crete, Greece. The goal of the symposium was to highlight recent advances and developments in the field [...] Read more.
The symposium, “Role of Nutrition in Alcoholic Liver Disease”, was held at the European Society for Biomedical Research on Alcoholism Congress on 9 October 2017 in Crete, Greece. The goal of the symposium was to highlight recent advances and developments in the field of alcohol and nutrition. The symposium was focused on experimental and clinical aspects in relation to the role of different types of dietary nutrients and malnutrition in the pathogenesis of alcoholic liver disease (ALD). The following is a summary of key research presented at this session. The speakers discussed the role of dietary fats and carbohydrates in the development and progression of alcohol-induced multi-organ pathology in animal models of ALD, analyzed novel nutrition-related therapeutics (specifically, betaine and zinc) in the treatment of ALD, and addressed clinical relevance of malnutrition and nutrition support in ALD. This summary of the symposium will benefit junior and senior faculty currently investigating alcohol-induced organ pathology as well as undergraduate, graduate, and post-graduate students and fellows. Full article
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21 pages, 1014 KiB  
Review
Rodent Models of Alcoholic Liver Disease: Role of Binge Ethanol Administration
by Shubha Ghosh Dastidar, Jeffrey B. Warner, Dennis R. Warner, Craig J. McClain and Irina A. Kirpich
Biomolecules 2018, 8(1), 3; https://doi.org/10.3390/biom8010003 - 13 Jan 2018
Cited by 87 | Viewed by 11251
Abstract
Both chronic and acute (binge) alcohol drinking are important health and economic concerns worldwide and prominent risk factors for the development of alcoholic liver disease (ALD). There are no FDA-approved medications to prevent or to treat any stage of ALD. Therefore, discovery of [...] Read more.
Both chronic and acute (binge) alcohol drinking are important health and economic concerns worldwide and prominent risk factors for the development of alcoholic liver disease (ALD). There are no FDA-approved medications to prevent or to treat any stage of ALD. Therefore, discovery of novel therapeutic strategies remains a critical need for patients with ALD. Relevant experimental animal models that simulate human drinking patterns and mimic the spectrum and severity of alcohol-induced liver pathology in humans are critical to our ability to identify new mechanisms and therapeutic targets. There are several animal models currently in use, including the most widely utilized chronic ad libitum ethanol (EtOH) feeding (Lieber–DeCarli liquid diet model), chronic intragastric EtOH administration (Tsukamoto–French model), and chronic-plus-binge EtOH challenge (Bin Gao—National Institute on Alcohol Abuse and Alcoholism (NIAAA) model). This review provides an overview of recent advances in rodent models of binge EtOH administration which help to recapitulate different features and etiologies of progressive ALD. These models include EtOH binge alone, and EtOH binge coupled with chronic EtOH intake, a high fat diet, or endotoxin challenge. We analyze the strengths, limitations, and translational relevance of these models, as well as summarize the liver injury outcomes and mechanistic insights. We further discuss the application(s) of binge EtOH models in examining alcohol-induced multi-organ pathology, sex- and age-related differences, as well as circadian rhythm disruption. Full article
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2017

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Review
Organ–Organ Crosstalk and Alcoholic Liver Disease
by Lauren G. Poole, Christine E. Dolin and Gavin E. Arteel
Biomolecules 2017, 7(3), 62; https://doi.org/10.3390/biom7030062 - 16 Aug 2017
Cited by 28 | Viewed by 10416
Abstract
Alcohol consumption is a common custom worldwide, and the toxic effects of alcohol on several target organs are well-understood. Given the poor prognosis of treating clinically-relevant alcoholic liver disease (ALD) (i.e., alcoholic hepatitis (AH) and cirrhosis), additional research is required to develop more [...] Read more.
Alcohol consumption is a common custom worldwide, and the toxic effects of alcohol on several target organs are well-understood. Given the poor prognosis of treating clinically-relevant alcoholic liver disease (ALD) (i.e., alcoholic hepatitis (AH) and cirrhosis), additional research is required to develop more effective therapies. While the stages of ALD have been well-characterized, targeted therapies to prevent or reverse this process in humans are still needed. Better understanding of risk factors and mechanisms underlying disease progression can lead to the development of rational therapies to prevent or reverse ALD in the clinic. A potential area of targeted therapy for ALD may be organ–organ communication in the early stages of the disease. In contrast to AH and end-stage liver diseases, the involvement of multiple organs in the development of ALD is less understood. The impact of these changes on pathology to the liver and other organs may not only influence disease progression during the development of the disease, but also outcomes of end stages diseases. The purpose of this review is to summarize the established and proposed communication between the liver and other organ systems that may contribute to the development and progression of liver disease, as well as to other organs. Potential mechanisms of this organ–organ communication are also discussed. Full article
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Review
Alcohol and Cancer: Mechanisms and Therapies
by Anuradha Ratna and Pranoti Mandrekar
Biomolecules 2017, 7(3), 61; https://doi.org/10.3390/biom7030061 - 14 Aug 2017
Cited by 87 | Viewed by 13437
Abstract
Several scientific and clinical studies have shown an association between chronic alcohol consumption and the occurrence of cancer in humans. The mechanism for alcohol-induced carcinogenesis has not been fully understood, although plausible events include genotoxic effects of acetaldehyde, cytochrome P450 2E1 (CYP2E1)-mediated generation [...] Read more.
Several scientific and clinical studies have shown an association between chronic alcohol consumption and the occurrence of cancer in humans. The mechanism for alcohol-induced carcinogenesis has not been fully understood, although plausible events include genotoxic effects of acetaldehyde, cytochrome P450 2E1 (CYP2E1)-mediated generation of reactive oxygen species, aberrant metabolism of folate and retinoids, increased estrogen, and genetic polymorphisms. Here, we summarize the impact of alcohol drinking on the risk of cancer development and potential underlying molecular mechanisms. The interactions between alcohol abuse, anti-tumor immune response, tumor growth, and metastasis are complex. However, multiple studies have linked the immunosuppressive effects of alcohol with tumor progression and metastasis. The influence of alcohol on the host immune system and the development of possible effective immunotherapy for cancer in alcoholics are also discussed here. The conclusive biological effects of alcohol on tumor progression and malignancy have not been investigated extensively using an animal model that mimics the human disease. This review provides insights into cancer pathogenesis in alcoholics, alcohol and immune interactions in different cancers, and scope and future of targeted immunotherapeutic modalities in patients with alcohol abuse. Full article
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Review
Alcohol, Adipose Tissue and Lipid Dysregulation
by Jennifer L. Steiner and Charles H. Lang
Biomolecules 2017, 7(1), 16; https://doi.org/10.3390/biom7010016 - 16 Feb 2017
Cited by 74 | Viewed by 12898
Abstract
Chronic alcohol consumption perturbs lipid metabolism as it increases adipose tissue lipolysis and leads to ectopic fat deposition within the liver and the development of alcoholic fatty liver disease. In addition to the recognition of the role of adipose tissue derived fatty acids [...] Read more.
Chronic alcohol consumption perturbs lipid metabolism as it increases adipose tissue lipolysis and leads to ectopic fat deposition within the liver and the development of alcoholic fatty liver disease. In addition to the recognition of the role of adipose tissue derived fatty acids in liver steatosis, alcohol also impacts other functions of adipose tissue and lipid metabolism. Lipid balance in response to long‐term alcohol intake favors adipose tissue loss and fatty acid efflux as lipolysis is upregulated and lipogenesis is either slightly decreased or unchanged. Study of the lipolytic and lipogenic pathways has identified several regulatory proteins modulated by alcohol that contribute to these effects. Glucose tolerance of adipose tissue is also impaired by chronic alcohol due to decreased glucose transporter‐4 availability at the membrane. As an endocrine organ, white adipose tissue (WAT) releases several adipokines that are negatively modulated following chronic alcohol consumption including adiponectin, leptin, and resistin. When these effects are combined with the enhanced expression of inflammatory mediators that are induced by chronic alcohol, a proinflammatory state develops within WAT, contributing to the observed lipodystrophy. Lastly, while chronic alcohol intake may enhance thermogenesis of brown adipose tissue (BAT), definitive mechanistic evidence is currently lacking. Overall, both WAT and BAT depots are impacted by chronic alcohol intake and the resulting lipodystrophy contributes to fat accumulation in peripheral organs, thereby enhancing the pathological state accompanying chronic alcohol use disorder. Full article
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Review
Role of Protein Quality Control Failure in Alcoholic Hepatitis Pathogenesis
by Samuel W. French, Maryam Masouminia, Sara Samadzadeh, Brittany C. Tillman, Alejandro Mendoza and Barbara A. French
Biomolecules 2017, 7(1), 11; https://doi.org/10.3390/biom7010011 - 08 Feb 2017
Cited by 12 | Viewed by 5580
Abstract
The mechanisms of protein quality control in hepatocytes in cases of alcoholic hepatitis (AH) including ufmylation, FAT10ylation, metacaspase 1 (Mca1), ERAD (endoplasmic reticulum-associated degradation), JUNQ (juxta nuclear quality control), IPOD (insoluble protein deposit) autophagocytosis, and ER stress are reviewed. The Mallory–Denk body (MDB) [...] Read more.
The mechanisms of protein quality control in hepatocytes in cases of alcoholic hepatitis (AH) including ufmylation, FAT10ylation, metacaspase 1 (Mca1), ERAD (endoplasmic reticulum-associated degradation), JUNQ (juxta nuclear quality control), IPOD (insoluble protein deposit) autophagocytosis, and ER stress are reviewed. The Mallory–Denk body (MDB) formation develops in the hepatocytes in alcoholic hepatitis as a consequence of the failure of these protein quality control mechanisms to remove misfolded and damaged proteins and to prevent MDB aggresome formation within the cytoplasm of hepatocytes. The proteins involved in the quality control pathways are identified, quantitated, and visualized by immunofluorescent antibody staining of liver biopsies from patients with AH. Quantification of the proteins are achieved by measuring the fluorescent intensity using a morphometric system. Ufmylation and FAT10ylation pathways were downregulated, Mca1 pathways were upregulated, autophagocytosis was upregulated, and ER stress PERK (protein kinase RNA-like endoplasmic reticulum kinase) and CHOP (CCAAT/enhancer-binding protein homologous protein) mechanisms were upregulated. In conclusion: Despite the upregulation of several pathways of protein quality control, aggresomes (MDBs) still formed in the hepatocytes in AH. The pathogenesis of AH is due to the failure of protein quality control, which causes balloon-cell change with MDB formation and ER stress. Full article
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Review
Key Events Participating in the Pathogenesis of Alcoholic Liver Disease
by Fernando Magdaleno, Chuck C. Blajszczak and Natalia Nieto
Biomolecules 2017, 7(1), 9; https://doi.org/10.3390/biom7010009 - 27 Jan 2017
Cited by 58 | Viewed by 11120
Abstract
Alcoholic liver disease (ALD) is a leading cause of morbidity and mortality worldwide. It ranges from fatty liver to steatohepatitis, fibrosis, cirrhosis and hepatocellular carcinoma.The most prevalent forms of ALD are alcoholic fatty liver, alcoholic hepatitis (AH) and alcoholic cirrhosis, which frequently progress [...] Read more.
Alcoholic liver disease (ALD) is a leading cause of morbidity and mortality worldwide. It ranges from fatty liver to steatohepatitis, fibrosis, cirrhosis and hepatocellular carcinoma.The most prevalent forms of ALD are alcoholic fatty liver, alcoholic hepatitis (AH) and alcoholic cirrhosis, which frequently progress as people continue drinking. ALD refers to a number of symptoms/deficits that contribute to liver injury. These include steatosis, inflammation, fibrosis and cirrhosis, which, when taken together, sequentially or simultaneously lead to significant disease progression. The pathogenesis of ALD, influenced by host and environmental factors, is currentlyonly partially understood. To date, lipopolysaccharide (LPS) translocation from the gut to the portal blood, aging, gender, increased infiltration and activation of neutrophils and bone marrow-derived macrophages along with alcohol plus iron metabolism, with its associated increase in reactive oxygen species (ROS), are all key events contributing to the pathogenesis of ALD. This review aimsto introduce the reader to the concept of alcohol‐mediated liver damage and the mechanisms driving injury. Full article
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2016

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Article
Chronic Binge Alcohol Administration Dysregulates Hippocampal Genes Involved in Immunity and Neurogenesis in Simian Immunodeficiency Virus-Infected Macaques
by John K. Maxi, Matt Dean, Jovanny Zabaleta, Krzysztof Reiss, Gregory J. Bagby, Steve Nelson, Peter J. Winsauer, Francesca Peruzzi and Patricia E. Molina
Biomolecules 2016, 6(4), 43; https://doi.org/10.3390/biom6040043 - 09 Nov 2016
Cited by 7 | Viewed by 4926
Abstract
Alcohol use disorders (AUD) exacerbate neurocognitive dysfunction in Human Immunodeficiency Virus (HIV+) patients. We have shown that chronic binge alcohol (CBA) administration (13–14 g EtOH/kg/wk) prior to and during simian immunodeficiency virus (SIV) infection in rhesus macaques unmasks learning deficits in operant learning [...] Read more.
Alcohol use disorders (AUD) exacerbate neurocognitive dysfunction in Human Immunodeficiency Virus (HIV+) patients. We have shown that chronic binge alcohol (CBA) administration (13–14 g EtOH/kg/wk) prior to and during simian immunodeficiency virus (SIV) infection in rhesus macaques unmasks learning deficits in operant learning and memory tasks. The underlying mechanisms of neurocognitive alterations due to alcohol and SIV are not known. This exploratory study examined the CBA-induced differential expression of hippocampal genes in SIV-infected (CBA/SIV+; n = 2) macaques in contrast to those of sucrose administered, SIV-infected (SUC/SIV+; n = 2) macaques. Transcriptomes of hippocampal samples dissected from brains obtained at necropsy (16 months post-SIV inoculation) were analyzed to determine differentially expressed genes. MetaCore from Thomson Reuters revealed enrichment of genes involved in inflammation, immune responses, and neurodevelopment. Functional relevance of these alterations was examined in vitro by exposing murine neural progenitor cells (NPCs) to ethanol (EtOH) and HIV trans-activator of transcription (Tat) protein. EtOH impaired NPC differentiation as indicated by decreased βIII tubulin expression. These findings suggest a role for neuroinflammation and neurogenesis in CBA/SIV neuropathogenesis and warrant further investigation of their potential contribution to CBA-mediated neurobehavioral deficits. Full article
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Review
Role of Transcription Factors in Steatohepatitis and Hypertension after Ethanol: The Epicenter of Metabolism
by Rais A. Ansari, Kazim Husain and Syed A. A. Rizvi
Biomolecules 2016, 6(3), 29; https://doi.org/10.3390/biom6030029 - 24 Jun 2016
Cited by 38 | Viewed by 10477
Abstract
Chronic alcohol consumption induces multi-organ damage, including alcoholic liver disease (ALD), pancreatitis and hypertension. Ethanol and ethanol metabolic products play a significant role in the manifestation of its toxicity. Ethanol metabolizes to acetaldehyde and produces reduced nicotinamide adenine dinucleotide (NADH) by cytosolic alcohol [...] Read more.
Chronic alcohol consumption induces multi-organ damage, including alcoholic liver disease (ALD), pancreatitis and hypertension. Ethanol and ethanol metabolic products play a significant role in the manifestation of its toxicity. Ethanol metabolizes to acetaldehyde and produces reduced nicotinamide adenine dinucleotide (NADH) by cytosolic alcohol dehydrogenase. Ethanol metabolism mediated by cytochrome-P450 2E1 causes oxidative stress due to increased production of reactive oxygen species (ROS). Acetaldehyde, increased redox cellular state and ROS activate transcription factors, which in turn activate genes for lipid biosynthesis and offer protection of hepatocytes from alcohol toxicity. Sterol regulatory element binding proteins (SREBPs) and peroxisome proliferator activated-receptors (PPARs) are two key lipogenic transcription factors implicated in the development of fatty liver in alcoholic and non-alcoholic steatohepatitis. SREBP-1 is activated in the livers of chronic ethanol abusers. An increase in ROS activates nuclear factor erythroid-2-related factor-2 (Nrf2) and hypoxia inducible factor (HIF) to provide protection to hepatocytes from ethanol toxicity. Under ethanol exposure, due to increased gut permeability, there is release of gram-negative bacteria-derived lipopolysaccharide (LPS) from intestine causing activation of immune response. In addition, the metabolic product, acetaldehyde, modifies the proteins in hepatocyte, which become antigens inviting auto-immune response. LPS activates macrophages, especially the liver resident macrophages, Kupffer cells. These Kupffer cells and circulating macrophages secrete various cytokines. The level of tumor necrosis factor-α (TNFα), interleukin-1beta (IL-1β), IL-6, IL-8 and IL-12 have been found elevated among chronic alcoholics. In addition to elevation of these cytokines, the peripheral iron (Fe2+) is also mobilized. An increased level of hepatic iron has been observed among alcoholics. Increased ROS, IL-1β, acetaldehyde, and increased hepatic iron, all activate nuclear factor-kappa B (NF-κB) transcription factor. Resolution of increased reactive oxygen species requires increased expression of genes responsible for dismutation of increased ROS which is partially achieved by IL-6 mediated activation of signal transducers and activators of transcription 3 (STAT3). In addition to these transcription factors, activator protein-1 may also be activated in hepatocytes due to its association with resolution of increased ROS. These transcription factors are central to alcohol-mediated hepatotoxicity. Full article
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Editorial
Multi-Organ Alcohol-Related Damage: Mechanisms and Treatment
by Natalia A. Osna and Kusum K. Kharbanda
Biomolecules 2016, 6(2), 20; https://doi.org/10.3390/biom6020020 - 15 Apr 2016
Cited by 21 | Viewed by 5484
Abstract
Alcohol consumption causes damage to various organs and systems.[...] Full article
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Article
The Involvement of Acetaldehyde in Ethanol-Induced Cell Cycle Impairment
by Marc A. Scheer, Katrina J. Schneider, Rochelle L. Finnigan, Eamon P. Maloney, Mark A. Wells and Dahn L. Clemens
Biomolecules 2016, 6(2), 17; https://doi.org/10.3390/biom6020017 - 31 Mar 2016
Cited by 8 | Viewed by 6421
Abstract
Background: Hepatocytes metabolize the vast majority of ingested ethanol. This metabolic activity results in hepatic toxicity and impairs the ability of hepatocytes to replicate. Previous work by our group has shown that ethanol metabolism results in a G2/M cell cycle arrest. The intent [...] Read more.
Background: Hepatocytes metabolize the vast majority of ingested ethanol. This metabolic activity results in hepatic toxicity and impairs the ability of hepatocytes to replicate. Previous work by our group has shown that ethanol metabolism results in a G2/M cell cycle arrest. The intent of these studies was to discern the roles of acetaldehyde and reactive oxygen, two of the major by-products of ethanol metabolism, in the G2/M cell cycle arrest. Methods: To investigate the role of ethanol metabolites in the cell cycle arrest, VA-13 and VL-17A cells were used. These are recombinant Hep G2 cells that express alcohol dehydrogenase or alcohol dehydrogenase and cytochrome P450 2E1, respectively. Cells were cultured with or without ethanol, lacking or containing the antioxidants N-acetylcysteine (NAC) or trolox, for three days. Cellular accumulation was monitored by the DNA content of the cultures. The accumulation of the cyclin-dependent kinase, Cdc2 in the inactive phosphorylated form (p-Cdc2) and the cyclin-dependent kinase inhibitor p21 were determined by immunoblot analysis. Results: Cultures maintained in the presence of ethanol demonstrated a G2/M cell cycle arrest that was associated with a reduction in DNA content and increased levels of p-Cdc2 and p21, compared with cells cultured in its absence. Inclusion of antioxidants in the ethanol containing media was unable to rescue the cells from the cell cycle arrest or these ethanol metabolism-mediated effects. Additionally, culturing the cells in the presence of acetaldehyde alone resulted in increased levels of p-Cdc2 and p21. Conclusions: Acetaldehyde produced during ethanol oxidation has a major role in the ethanol metabolism-mediated G2/M cell cycle arrest, and the concurrent accumulation of p21 and p-Cdc2. Although reactive oxygen species are thought to have a significant role in ethanol-induced hepatocellular damage, they may have a less important role in the inability of hepatocytes to replace dead or damaged cells. Full article
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Review
Multidisciplinary View of Alcohol Use Disorder: From a Psychiatric Illness to a Major Liver Disease
by Stefano Gitto, Lucia Golfieri, Fabio Caputo, Silvana Grandi and Pietro Andreone
Biomolecules 2016, 6(1), 11; https://doi.org/10.3390/biom6010011 - 15 Jan 2016
Cited by 19 | Viewed by 7440
Abstract
Alcohol use disorder is a significant health problem being a cause of increased morbidity and mortality worldwide. Alcohol-related illness has a relevant economic impact on the society and a negative influence on the life of patients and their family members. Psychosocial support might [...] Read more.
Alcohol use disorder is a significant health problem being a cause of increased morbidity and mortality worldwide. Alcohol-related illness has a relevant economic impact on the society and a negative influence on the life of patients and their family members. Psychosocial support might be useful in the management of people affected by alcohol use disorder since psychiatric and pharmaceutical approaches show some limits. In fact, many drugs are accessible for the treatment of alcohol disorder, but only Baclofen is functional as an anti-craving drug in patients with advanced liver disease. The alcohol-related liver damage represents the most frequent cause of advanced liver disease in Europe, and it is the main cause of death among adults with high alcohol consumption. The multidisciplinary action of clinical-psychologists, psychiatrics and hepatologists, is essential in the management of patients with alcohol liver disease especially in the case of liver transplantation. In general, the multidisciplinary approach is necessary in prevention, in framing patients and in the treatment. More resources should be used in prevention and research with the main aim of decreasing the harmful alcohol consumption. Full article
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Article
Moderate (2%, v/v) Ethanol Feeding Alters Hepatic Wound Healing after Acute Carbon Tetrachloride Exposure in Mice
by Krutika T. Deshpande, Shinlan Liu, Jennifer M. McCracken, Lu Jiang, Ta Ehpaw Gaw, Lindsey N. Kaydo, Zachary C. Richard, Maura F. O’Neil and Michele T. Pritchard
Biomolecules 2016, 6(1), 5; https://doi.org/10.3390/biom6010005 - 06 Jan 2016
Cited by 13 | Viewed by 7405
Abstract
Wound healing consists of three overlapping phases: inflammation, proliferation, and matrix synthesis and remodeling. Prolonged alcohol abuse can cause liver fibrosis due to deregulated matrix remodeling. Previous studies demonstrated that moderate ethanol feeding enhances liver fibrogenic markers and frank fibrosis independent of differences [...] Read more.
Wound healing consists of three overlapping phases: inflammation, proliferation, and matrix synthesis and remodeling. Prolonged alcohol abuse can cause liver fibrosis due to deregulated matrix remodeling. Previous studies demonstrated that moderate ethanol feeding enhances liver fibrogenic markers and frank fibrosis independent of differences in CCl4-induced liver injury. Our objective was to determine whether or not other phases of the hepatic wound healing response were affected by moderate ethanol after CCl4 exposure. Mice were fed moderate ethanol (2% v/v) for two days and then were exposed to CCl4 and euthanized 24–96 h later. Liver injury was not different between pair- and ethanol-fed mice; however, removal of necrotic tissue was delayed after CCl4-induced liver injury in ethanol-fed mice. Inflammation, measured by TNFα mRNA and protein and hepatic Ly6c transcript accumulation, was reduced and associated with enhanced hepatocyte apoptosis after ethanol feeding. Hepatocytes entered the cell cycle equivalently in pair- and ethanol-fed mice after CCl4 exposure, but hepatocyte proliferation was prolonged in livers from ethanol-fed mice. CCl4-induced hepatic stellate cell activation was increased and matrix remodeling was prolonged in ethanol-fed mice compared to controls. Taken together, moderate ethanol affected each phase of the wound healing response to CCl4. These data highlight previously unknown effects of moderate ethanol exposure on hepatic wound healing after acute hepatotoxicant exposure. Full article
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Review
Guardian of Genetic Messenger-RNA-Binding Proteins
by Antje Anji and Meena Kumari
Biomolecules 2016, 6(1), 4; https://doi.org/10.3390/biom6010004 - 06 Jan 2016
Cited by 12 | Viewed by 8287
Abstract
RNA in cells is always associated with RNA-binding proteins that regulate all aspects of RNA metabolism including RNA splicing, export from the nucleus, RNA localization, mRNA turn-over as well as translation. Given their diverse functions, cells express a variety of RNA-binding proteins, which [...] Read more.
RNA in cells is always associated with RNA-binding proteins that regulate all aspects of RNA metabolism including RNA splicing, export from the nucleus, RNA localization, mRNA turn-over as well as translation. Given their diverse functions, cells express a variety of RNA-binding proteins, which play important roles in the pathologies of a number of diseases. In this review we focus on the effect of alcohol on different RNA-binding proteins and their possible contribution to alcohol-related disorders, and discuss the role of these proteins in the development of neurological diseases and cancer. We further discuss the conventional methods and newer techniques that are employed to identify RNA-binding proteins. Full article
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Review
Alcoholic Liver Disease: Update on the Role of Dietary Fat
by Irina A. Kirpich, Matthew E. Miller, Matthew C. Cave, Swati Joshi-Barve and Craig J. McClain
Biomolecules 2016, 6(1), 1; https://doi.org/10.3390/biom6010001 - 06 Jan 2016
Cited by 56 | Viewed by 12768
Abstract
Alcoholic liver disease (ALD) spans a spectrum of liver pathology, including fatty liver, alcoholic steatohepatitis, and cirrhosis. Accumulating evidence suggests that dietary factors, including dietary fat, as well as alcohol, play critical roles in the pathogenesis of ALD. The protective effects of dietary [...] Read more.
Alcoholic liver disease (ALD) spans a spectrum of liver pathology, including fatty liver, alcoholic steatohepatitis, and cirrhosis. Accumulating evidence suggests that dietary factors, including dietary fat, as well as alcohol, play critical roles in the pathogenesis of ALD. The protective effects of dietary saturated fat (SF) and deleterious effects of dietary unsaturated fat (USF) on alcohol-induced liver pathology are well recognized and documented in experimental animal models of ALD. Moreover, it has been demonstrated in an epidemiological study of alcoholic cirrhosis that dietary intake of SF was associated with a lower mortality rates, whereas dietary intake of USF was associated with a higher mortality. In addition, oxidized lipids (dietary and in vivo generated) may play a role in liver pathology. The understanding of how dietary fat contributes to the ALD pathogenesis will enhance our knowledge regarding the molecular mechanisms of ALD development and progression, and may result in the development of novel diet-based therapeutic strategies for ALD management. This review explores the relevant scientific literature and provides a current understanding of recent advances regarding the role of dietary lipids in ALD pathogenesis. Full article
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2015

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301 KiB  
Review
Role of microRNAs in Alcohol-Induced Multi-Organ Injury
by Sathish Kumar Natarajan, Joseph M. Pachunka and Justin L. Mott
Biomolecules 2015, 5(4), 3309-3338; https://doi.org/10.3390/biom5043309 - 20 Nov 2015
Cited by 44 | Viewed by 9206
Abstract
Alcohol consumption and its abuse is a major health problem resulting in significant healthcare cost in the United States. Chronic alcoholism results in damage to most of the vital organs in the human body. Among the alcohol-induced injuries, alcoholic liver disease is one [...] Read more.
Alcohol consumption and its abuse is a major health problem resulting in significant healthcare cost in the United States. Chronic alcoholism results in damage to most of the vital organs in the human body. Among the alcohol-induced injuries, alcoholic liver disease is one of the most prevalent in the United States. Remarkably, ethanol alters expression of a wide variety of microRNAs that can regulate alcohol-induced complications or dysfunctions. In this review, we will discuss the role of microRNAs in alcoholic pancreatitis, alcohol-induced liver damage, intestinal epithelial barrier dysfunction, and brain damage including altered hippocampus structure and function, and neuronal loss, alcoholic cardiomyopathy, and muscle damage. Further, we have reviewed the role of altered microRNAs in the circulation, teratogenic effects of alcohol, and during maternal or paternal alcohol consumption. Full article
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Article
High Intrinsic Aerobic Capacity Protects against Ethanol-Induced Hepatic Injury and Metabolic Dysfunction: Study Using High Capacity Runner Rat Model
by Nicholas Szary, R. Scott Rector, Grace M. Uptergrove, Suzanne E. Ridenhour, Shivendra D. Shukla, John P. Thyfault, Lauren G. Koch, Steven L. Britton and Jamal A. Ibdah
Biomolecules 2015, 5(4), 3295-3308; https://doi.org/10.3390/biom5043295 - 20 Nov 2015
Cited by 6 | Viewed by 12267
Abstract
Rats artificially selected over several generations for high intrinsic endurance/aerobic capacity resulting in high capacity runners (HCR) has been developed to study the links between high aerobic fitness and protection from metabolic diseases (Wisloff et al., Science, 2005). We have previously shown that [...] Read more.
Rats artificially selected over several generations for high intrinsic endurance/aerobic capacity resulting in high capacity runners (HCR) has been developed to study the links between high aerobic fitness and protection from metabolic diseases (Wisloff et al., Science, 2005). We have previously shown that the HCR strain have elevated hepatic mitochondrial content and oxidative capacity. In this study, we tested if the elevated hepatic mitochondrial content in the HCR rat would provide “metabolic protection” from chronic ethanol-induced hepatic steatosis and injury. The Leiber-Decarli liquid diet with ethanol (7% v/v; HCR-E) and without (HCR-C) was given to HCR rats (n = 8 per group) from 14 to 20 weeks of age that were weight matched and pair-fed to assure isocaloric intake. Hepatic triglyceride (TG) content and macro- and microvesicular steatosis were significantly greater in HCR-E compared with HCR-C (p < 0.05). In addition, hepatic superoxide dismutase activity and glutathione levels were significantly (p < 0.05) reduced in the HCR-E rats. This hepatic phenotype also was associated with reduced total hepatic fatty acid oxidation (p = 0.03) and ß-hydroxyacyl-CoA dehydrogenase activity (p = 0.01), and reductions in microsomal triglyceride transfer protein and apoB-100 protein content (p = 0.01) in HCR-E animals. However, despite these documented hepatic alterations, ethanol ingestion failed to induce significant hepatic liver injury, including no changes in hepatic inflammation, or serum alanine amino transferase (ALTs), free fatty acids (FFAs), triglycerides (TGs), insulin, or glucose. High intrinsic aerobic fitness did not reduce ethanol-induced hepatic steatosis, but protected against ethanol-induced hepatic injury and systemic metabolic dysfunction in a high aerobic capacity rat model. Full article
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Article
In Vivo Acute on Chronic Ethanol Effects in Liver: A Mouse Model Exhibiting Exacerbated Injury, Altered Metabolic and Epigenetic Responses
by Shivendra D. Shukla, Annayya R. Aroor, Ricardo Restrepo, Kusum K. Kharbanda and Jamal A. Ibdah
Biomolecules 2015, 5(4), 3280-3294; https://doi.org/10.3390/biom5043280 - 20 Nov 2015
Cited by 21 | Viewed by 11879
Abstract
Chronic alcoholics who also binge drink (i.e., acute on chronic) are prone to an exacerbated liver injury but its mechanism is not understood. We therefore investigated the in vivo effects of chronic and binge ethanol ingestion and compared to chronic ethanol [...] Read more.
Chronic alcoholics who also binge drink (i.e., acute on chronic) are prone to an exacerbated liver injury but its mechanism is not understood. We therefore investigated the in vivo effects of chronic and binge ethanol ingestion and compared to chronic ethanol followed by three repeat binge ethanol on the liver of male C57/BL6 mice fed ethanol in liquid diet (4%) for four weeks followed by binge ethanol (intragastric administration, 3.5 g/kg body weight, three doses, 12h apart). Chronic followed by binge ethanol exacerbated fat accumulation, necrosis, decrease in hepatic SAM and SAM:SAH ratio, increase in adenosine levels, and elevated CYP2E1 levels. Histone H3 lysine acetylation (H3AcK9), dually modified phosphoacetylated histone H3 (H3AcK9/PS10), and phosphorylated H2AX increased after binge whereas phosphorylation of histone H3 ser 10 (H3S10) and H3 ser 28 (H3S28) increased after chronic ethanol-binge. Histone H3 lysine 4 and 9 dimethylation increased with a marked dimethylation in H3K9 in chronic ethanol binge group. Trimethylated histone H3 levels did not change. Nuclear levels of histone acetyl transferase GCN5 and histone deacetylase HDAC3 were elevated whereas phospho-CREB decreased in a distinctive manner. Taken together, acute on chronic ethanol ingestion caused amplification of liver injury and elicited characteristic profiles of histone modifications, metabolic alterations, and changes in nuclear protein levels. These findings demonstrate that chronic ethanol exposure renders liver more susceptible to repeat acute/binge ethanol induced acceleration of alcoholic liver disease. Full article
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Article
Alcohol and Apoptosis: Friends or Foes?
by Ana Rodriguez, Karan Chawla, Nsini A. Umoh, Valerie M. Cousins, Assama Ketegou, Madhumati G. Reddy, Mustafa AlRubaiee, Georges E. Haddad and Mark W. Burke
Biomolecules 2015, 5(4), 3193-3203; https://doi.org/10.3390/biom5043193 - 19 Nov 2015
Cited by 25 | Viewed by 6588
Abstract
Alcohol abuse causes 79,000 deaths stemming from severe organ damage in the United States every year. Clinical manifestations of long-term alcohol abuse on the cardiac muscle include defective contractility with the development of dilated cardiomyopathy and low-output heart failure; which has poor prognosis [...] Read more.
Alcohol abuse causes 79,000 deaths stemming from severe organ damage in the United States every year. Clinical manifestations of long-term alcohol abuse on the cardiac muscle include defective contractility with the development of dilated cardiomyopathy and low-output heart failure; which has poor prognosis with less than 25% survival for more than three years. In contrast, low alcohol consumption has been associated with reduced risk of cardiovascular disease, however the mechanism of this phenomenon remains elusive. The aim of this study was to determine the significance of apoptosis as a mediating factor in cardiac function following chronic high alcohol versus low alcohol exposure. Adult rats were provided 5 mM (low alcohol), 100 mM (high alcohol) or pair-fed non-alcohol controls for 4–5 months. The hearts were dissected, sectioned and stained with cresyl violet or immunohistochemically for caspase-3, a putative marker for apoptosis. Cardiomyocytes were isolated to determine the effects of alcohol exposure on cell contraction and relaxation. High alcohol animals displayed a marked thinning of the left ventricular wall combined with elevated caspase-3 activity and decreased contractility. In contrast, low alcohol was associated with increased contractility and decreased apoptosis suggesting an overall protective mechanism induced by low levels of alcohol exposure. Full article
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Article
Skin Immunization Obviates Alcohol-Related Immune Dysfunction
by Rhonda M. Brand, John Mark Stottlemyer, Rachel A. Cline, Cara Donahue, Jaideep Behari and Louis D. Falo Jr.
Biomolecules 2015, 5(4), 3009-3028; https://doi.org/10.3390/biom5043009 - 06 Nov 2015
Cited by 3 | Viewed by 6964
Abstract
Alcoholics suffer from immune dysfunction that can impede vaccine efficacy. If ethanol (EtOH)-induced immune impairment is in part a result of direct exposure of immune cells to EtOH, then reduced levels of exposure could result in less immune dysfunction. As alcohol ingestion results [...] Read more.
Alcoholics suffer from immune dysfunction that can impede vaccine efficacy. If ethanol (EtOH)-induced immune impairment is in part a result of direct exposure of immune cells to EtOH, then reduced levels of exposure could result in less immune dysfunction. As alcohol ingestion results in lower alcohol levels in skin than blood, we hypothesized that the skin immune network may be relatively preserved, enabling skin-targeted immunizations to obviate the immune inhibitory effects of alcohol consumption on conventional vaccines. We employed the two most common chronic EtOH mouse feeding models, the liver-damaging Lieber-DeCarli (LD) and liver-sparing Meadows-Cook (MC) diets, to examine the roles of EtOH and/or EtOH-induced liver dysfunction on alcohol related immunosuppression. Pair-fed mice were immunized against the model antigen ovalbumin (OVA) by DNA immunization or against flu by administering the protein-based influenza vaccine either systemically (IV, IM), directly to liver (hydrodynamic), or cutaneously (biolistic, ID). We measured resulting tissue EtOH levels, liver stress, regulatory T cell (Treg), and myeloid-derived suppressor cell (MDSC) populations. We compared immune responsiveness by measuring delayed-type hypersensitivity (DTH), antigen-specific cytotoxic T lymphocyte (CTL), and antibody induction as a function of delivery route and feeding model. We found that, as expected, and independent of the feeding model, EtOH ingestion inhibits DTH, CTL lysis, and antigen-specific total IgG induced by traditional systemic vaccines. On the other hand, skin-targeted vaccines were equally immunogenic in alcohol-exposed and non-exposed subjects, suggesting that cutaneous immunization may result in more efficacious vaccination in alcohol-ingesting subjects. Full article
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Review
Alcohol, Aldehydes, Adducts and Airways
by Muna Sapkota and Todd A. Wyatt
Biomolecules 2015, 5(4), 2987-3008; https://doi.org/10.3390/biom5042987 - 05 Nov 2015
Cited by 51 | Viewed by 10954
Abstract
Drinking alcohol and smoking cigarettes results in the formation of reactive aldehydes in the lung, which are capable of forming adducts with several proteins and DNA. Acetaldehyde and malondialdehyde are the major aldehydes generated in high levels in the lung of subjects with [...] Read more.
Drinking alcohol and smoking cigarettes results in the formation of reactive aldehydes in the lung, which are capable of forming adducts with several proteins and DNA. Acetaldehyde and malondialdehyde are the major aldehydes generated in high levels in the lung of subjects with alcohol use disorder who smoke cigarettes. In addition to the above aldehydes, several other aldehydes like 4-hydroxynonenal, formaldehyde and acrolein are also detected in the lung due to exposure to toxic gases, vapors and chemicals. These aldehydes react with nucleophilic targets in cells such as DNA, lipids and proteins to form both stable and unstable adducts. This adduction may disturb cellular functions as well as damage proteins, nucleic acids and lipids. Among several adducts formed in the lung, malondialdehyde DNA (MDA-DNA) adduct and hybrid malondialdehyde-acetaldehyde (MAA) protein adducts have been shown to initiate several pathological conditions in the lung. MDA-DNA adducts are pre-mutagenic in mammalian cells and induce frame shift and base-pair substitution mutations, whereas MAA protein adducts have been shown to induce inflammation and inhibit wound healing. This review provides an insight into different reactive aldehyde adducts and their role in the pathogenesis of lung disease. Full article
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Review
Update on Alcoholic Hepatitis
by Natalie J. Torok
Biomolecules 2015, 5(4), 2978-2986; https://doi.org/10.3390/biom5042978 - 02 Nov 2015
Cited by 29 | Viewed by 6559
Abstract
Alcoholic liver disease is one of the most prevalent liver diseases worldwide, and a major cause of morbidity and mortality. Alcoholic hepatitis is a severe form of liver injury in patients with alcohol abuse, can present as an acute on chronic liver failure [...] Read more.
Alcoholic liver disease is one of the most prevalent liver diseases worldwide, and a major cause of morbidity and mortality. Alcoholic hepatitis is a severe form of liver injury in patients with alcohol abuse, can present as an acute on chronic liver failure associated with a rapid decline in liver synthetic function, and consequent increase in mortality. Despite therapy, about 30%–50% of patients with severe alcoholic hepatitis eventually die. The pathogenic pathways that lead to the development of alcoholic hepatitis are complex and involve oxidative stress, gut dysbiosis, and dysregulation of the innate and adaptive immune system with injury to the parenchymal cells and activation of hepatic stellate cells. As accepted treatment approaches are currently limited, a better understanding of the pathophysiology would be required to generate new approaches that improve outcomes. This review focuses on recent advances in the diagnosis, pathogenesis of alcoholic hepatitis and novel treatment strategies. Full article
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Review
Chronic Ethanol Exposure: Pathogenesis of Pulmonary Disease and Dysfunction
by Nicole Traphagen, Zhi Tian and Diane Allen-Gipson
Biomolecules 2015, 5(4), 2840-2853; https://doi.org/10.3390/biom5042840 - 20 Oct 2015
Cited by 20 | Viewed by 6300
Abstract
Ethanol (EtOH) is the world’s most commonly used drug, and has been widely recognized as a risk factor for developing lung disorders. Chronic EtOH exposure affects all of the organ systems in the body and increases the risk of developing pulmonary diseases such [...] Read more.
Ethanol (EtOH) is the world’s most commonly used drug, and has been widely recognized as a risk factor for developing lung disorders. Chronic EtOH exposure affects all of the organ systems in the body and increases the risk of developing pulmonary diseases such as acute lung injury and pneumonia, while exacerbating the symptoms and resulting in increased mortality in many other lung disorders. EtOH and its metabolites inhibit the immune response of alveolar macrophages (AMs), increase airway leakage, produce damaging reactive oxygen species (ROS), and disrupt the balance of antioxidants/oxidants within the lungs. In this article, we review the role of EtOH exposure in the pathogenesis and progression of pulmonary disease. Full article
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Article
Autophagy Protects against CYP2E1/Chronic Ethanol-Induced Hepatotoxicity
by Yongke Lu and Arthur I. Cederbaum
Biomolecules 2015, 5(4), 2659-2674; https://doi.org/10.3390/biom5042659 - 16 Oct 2015
Cited by 48 | Viewed by 8615
Abstract
Autophagy is an intracellular pathway by which lysosomes degrade and recycle long-lived proteins and cellular organelles. The effects of ethanol on autophagy are complex but recent studies have shown that autophagy serves a protective function against ethanol-induced liver injury. Autophagy was found to [...] Read more.
Autophagy is an intracellular pathway by which lysosomes degrade and recycle long-lived proteins and cellular organelles. The effects of ethanol on autophagy are complex but recent studies have shown that autophagy serves a protective function against ethanol-induced liver injury. Autophagy was found to also be protective against CYP2E1-dependent toxicity in vitro in HepG2 cells which express CYP2E1 and in vivo in an acute alcohol/CYPE1-dependent liver injury model. The goal of the current report was to extend the previous in vitro and acute in vivo experiments to a chronic ethanol model to evaluate whether autophagy is also protective against CYP2E1-dependent liver injury in a chronic ethanol-fed mouse model. Wild type (WT), CYP2E1 knockout (KO) or CYP2E1 humanized transgenic knockin (KI), mice were fed an ethanol liquid diet or control dextrose diet for four weeks. In the last week, some mice received either saline or 3-methyladenine (3-MA), an inhibitor of autophagy, or rapamycin, which stimulates autophagy. Inhibition of autophagy by 3-MA potentiated the ethanol-induced increases in serum transaminase and triglyceride levels in the WT and KI mice but not KO mice, while rapamycin prevented the ethanol liver injury. Treatment with 3-MA enhanced the ethanol-induced fat accumulation in WT mice and caused necrosis in the KI mice; little or no effect was found in the ethanol-fed KO mice or any of the dextrose-fed mice. 3-MA treatment further lowered the ethanol-decrease in hepatic GSH levels and further increased formation of TBARS in WT and KI mice, whereas rapamycin blunted these effects of ethanol. Neither 3-MA nor rapamycin treatment affected CYP2E1 catalytic activity or content or the induction CYP2E1 by ethanol. The 3-MA treatment decreased levels of Beclin-1 and Atg 7 but increased levels of p62 in the ethanol-fed WT and KI mice whereas rapamycin had the opposite effects, validating inhibition and stimulation of autophagy, respectively. These results suggest that autophagy is protective against CYP2E1-dependent liver injury in a chronic ethanol-fed mouse model. We speculate that autophagy-dependent processes such as mitophagy and lipophagy help to minimize ethanol-induced CYP2E1-dependent oxidative stress and therefore the subsequent liver injury and steatosis. Attempts to stimulate autophagy may be helpful in lowering ethanol and CYP2E1-dependent liver toxicity. Full article
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Article
Modulation of Intestinal Barrier and Bacterial Endotoxin Production Contributes to the Beneficial Effect of Nicotinic Acid on Alcohol-Induced Endotoxemia and Hepatic Inflammation in Rats
by Wei Zhong, Qiong Li, Wenliang Zhang, Qian Sun, Xinguo Sun and Zhanxiang Zhou
Biomolecules 2015, 5(4), 2643-2658; https://doi.org/10.3390/biom5042643 - 16 Oct 2015
Cited by 23 | Viewed by 6886
Abstract
Alcohol consumption causes nicotinic acid deficiency. The present study was undertaken to determine whether dietary nicotinic acid supplementation provides beneficial effects on alcohol-induced endotoxin signaling and the possible mechanisms at the gut-liver axis. Male Sprague-Dawley rats were pair-fed the Lieber-DeCarli liquid diets containing [...] Read more.
Alcohol consumption causes nicotinic acid deficiency. The present study was undertaken to determine whether dietary nicotinic acid supplementation provides beneficial effects on alcohol-induced endotoxin signaling and the possible mechanisms at the gut-liver axis. Male Sprague-Dawley rats were pair-fed the Lieber-DeCarli liquid diets containing ethanol or isocaloric maltose dextrin for eight weeks, with or without dietary supplementation with 750 mg/liter nicotinic acid. Chronic alcohol feeding elevated the plasma endotoxin level and activated hepatic endotoxin signaling cascade, which were attenuated by nicotinic acid supplementation. Alcohol consumption remarkably decreased the mRNA levels of claudin-1, claudin-5, and ZO-1 in the distal intestine, whereas nicotinic acid significantly up-regulated these genes. The concentrations of endotoxin, ethanol, and acetaldehyde in the intestinal contents were increased by alcohol exposure, and niacin supplementation reduced the intestinal endotoxin and acetaldehyde levels. Nicotinic acid supplementation upregulated the intestinal genes involved in aldehyde detoxification via transcriptional regulation. These results demonstrate that modulation of the intestinal barrier function and bacterial endotoxin production accounts for the inhibitory effects of nicotinic acid on alcohol-induced endotoxemia and hepatic inflammation. Full article
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Review
A Mechanistic Review of Mitophagy and Its Role in Protection against Alcoholic Liver Disease
by Jessica A. Williams and Wen-Xing Ding
Biomolecules 2015, 5(4), 2619-2642; https://doi.org/10.3390/biom5042619 - 16 Oct 2015
Cited by 54 | Viewed by 9312
Abstract
Alcoholic liver disease (ALD) is a major health problem worldwide, and alcohol is well-known to cause mitochondrial damage, which exacerbates alcohol-induced liver injury and steatosis. No successful treatments are currently available for treating ALD. Therefore, a better understanding of mechanisms involved in regulation [...] Read more.
Alcoholic liver disease (ALD) is a major health problem worldwide, and alcohol is well-known to cause mitochondrial damage, which exacerbates alcohol-induced liver injury and steatosis. No successful treatments are currently available for treating ALD. Therefore, a better understanding of mechanisms involved in regulation of mitochondrial homeostasis in the liver and how these mechanisms may protect against alcohol-induced liver disease is needed for future development of better therapeutic options for ALD. Mitophagy is a key mechanism for maintaining mitochondrial homeostasis by removing damaged mitochondria, and mitophagy protects against alcohol-induced liver injury. Parkin, an E3 ubiquitin ligase, is well-known to induce mitophagy in in vitro models although Parkin-independent mechanisms for mitophagy induction also exist. In this review, we discuss the roles of Parkin and mitophagy in protection against alcohol-induced liver injury and steatosis. We also discuss Parkin-independent mechanisms for mitophagy induction, which have not yet been evaluated in the liver but may also potentially have a protective role against ALD. In addition to mitophagy, mitochondrial spheroid formation may also provide a novel mechanism of protection against ALD, but the role of mitochondrial spheroids in protection against ALD progression needs to be further explored. Targeting removal of damaged mitochondria by mitophagy or inducing formation of mitochondrial spheroids may be promising therapeutic options for treatment of ALD. Full article
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Review
Alcohol and the Intestine
by Sheena Patel, Rama Behara, Garth R. Swanson, Christopher B. Forsyth, Robin M. Voigt and Ali Keshavarzian
Biomolecules 2015, 5(4), 2573-2588; https://doi.org/10.3390/biom5042573 - 15 Oct 2015
Cited by 63 | Viewed by 12790
Abstract
Alcohol abuse is a significant contributor to the global burden of disease and can lead to tissue damage and organ dysfunction in a subset of alcoholics. However, a subset of alcoholics without any of these predisposing factors can develop alcohol-mediated organ injury. The [...] Read more.
Alcohol abuse is a significant contributor to the global burden of disease and can lead to tissue damage and organ dysfunction in a subset of alcoholics. However, a subset of alcoholics without any of these predisposing factors can develop alcohol-mediated organ injury. The gastrointestinal tract (GI) could be an important source of inflammation in alcohol-mediated organ damage. The purpose of review was to evaluate mechanisms of alcohol-induced endotoxemia (including dysbiosis and gut leakiness), and highlight the predisposing factors for alcohol-induced dysbiosis and gut leakiness to endotoxins. Barriers, including immunologic, physical, and biochemical can regulate the passage of toxins into the portal and systemic circulation. In addition, a host of environmental interactions including those influenced by circadian rhythms can impact alcohol-induced organ pathology. There appears to be a role for therapeutic measures to mitigate alcohol-induced organ damage by normalizing intestinal dysbiosis and/or improving intestinal barrier integrity. Ultimately, the inflammatory process that drives progression into organ damage from alcohol appears to be multifactorial. Understanding the role of the intestine in the pathogenesis of alcoholic liver disease can pose further avenues for pathogenic and treatment approaches. Full article
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Review
Endoplasmic Reticulum Stress and Ethanol Neurotoxicity
by Fanmuyi Yang and Jia Luo
Biomolecules 2015, 5(4), 2538-2553; https://doi.org/10.3390/biom5042538 - 14 Oct 2015
Cited by 61 | Viewed by 9147
Abstract
Ethanol abuse affects virtually all organ systems and the central nervous system (CNS) is particularly vulnerable to excessive ethanol exposure. Ethanol exposure causes profound damages to both the adult and developing brain. Prenatal ethanol exposure induces fetal alcohol spectrum disorders (FASD) which is [...] Read more.
Ethanol abuse affects virtually all organ systems and the central nervous system (CNS) is particularly vulnerable to excessive ethanol exposure. Ethanol exposure causes profound damages to both the adult and developing brain. Prenatal ethanol exposure induces fetal alcohol spectrum disorders (FASD) which is associated with mental retardation and other behavioral deficits. A number of potential mechanisms have been proposed for ethanol-induced brain damage; these include the promotion of neuroinflammation, interference with signaling by neurotrophic factors, induction of oxidative stress, modulation of retinoid acid signaling, and thiamine deficiency. The endoplasmic reticulum (ER) regulates posttranslational protein processing and transport. The accumulation of unfolded or misfolded proteins in the ER lumen triggers ER stress and induces unfolded protein response (UPR) which are mediated by three transmembrane ER signaling proteins: pancreatic endoplasmic reticulum kinase (PERK), inositol-requiring enzyme 1 (IRE1), and activating transcription factor 6 (ATF6). UPR is initiated to protect cells from overwhelming ER protein loading. However, sustained ER stress may result in cell death. ER stress has been implied in various CNS injuries, including brain ischemia, traumatic brain injury, and aging-associated neurodegeneration, such as Alzheimer’s disease (AD), Huntington’s disease (HD), Amyotrophic lateral sclerosis (ALS), and Parkinson’s disease (PD). However, effects of ethanol on ER stress in the CNS receive less attention. In this review, we discuss recent progress in the study of ER stress in ethanol-induced neurotoxicity. We also examine the potential mechanisms underlying ethanol-mediated ER stress and the interaction among ER stress, oxidative stress and autophagy in the context of ethanol neurotoxicity. Full article
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Review
The Molecular Circadian Clock and Alcohol-Induced Liver Injury
by Uduak S. Udoh, Jennifer A. Valcin, Karen L. Gamble and Shannon M. Bailey
Biomolecules 2015, 5(4), 2504-2537; https://doi.org/10.3390/biom5042504 - 14 Oct 2015
Cited by 35 | Viewed by 14834
Abstract
Emerging evidence from both experimental animal studies and clinical human investigations demonstrates strong connections among circadian processes, alcohol use, and alcohol-induced tissue injury. Components of the circadian clock have been shown to influence the pathophysiological effects of alcohol. Conversely, alcohol may alter the [...] Read more.
Emerging evidence from both experimental animal studies and clinical human investigations demonstrates strong connections among circadian processes, alcohol use, and alcohol-induced tissue injury. Components of the circadian clock have been shown to influence the pathophysiological effects of alcohol. Conversely, alcohol may alter the expression of circadian clock genes and the rhythmic behavioral and metabolic processes they regulate. Therefore, we propose that alcohol-mediated disruption in circadian rhythms likely underpins many adverse health effects of alcohol that cut across multiple organ systems. In this review, we provide an overview of the circadian clock mechanism and showcase results from new studies in the alcohol field implicating the circadian clock as a key target of alcohol action and toxicity in the liver. We discuss various molecular events through which alcohol may work to negatively impact circadian clock-mediated processes in the liver, and contribute to tissue pathology. Illuminating the mechanistic connections between the circadian clock and alcohol will be critical to the development of new preventative and pharmacological treatments for alcohol use disorders and alcohol-mediated organ diseases. Full article
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Review
Potential Role of the Gut/Liver/Lung Axis in Alcohol-Induced Tissue Pathology
by Veronica L. Massey, Juliane I. Beier, Jeffrey D. Ritzenthaler, Jesse Roman and Gavin E. Arteel
Biomolecules 2015, 5(4), 2477-2503; https://doi.org/10.3390/biom5042477 - 30 Sep 2015
Cited by 28 | Viewed by 8455
Abstract
Both Alcoholic Liver Disease (ALD) and alcohol-related susceptibility to acute lung injury are estimated to account for the highest morbidity and mortality related to chronic alcohol abuse and, thus, represent a focus of intense investigation. In general, alcohol-induced derangements to both organs are [...] Read more.
Both Alcoholic Liver Disease (ALD) and alcohol-related susceptibility to acute lung injury are estimated to account for the highest morbidity and mortality related to chronic alcohol abuse and, thus, represent a focus of intense investigation. In general, alcohol-induced derangements to both organs are considered to be independent and are often evaluated separately. However, the liver and lung share many general responses to damage, and specific responses to alcohol exposure. For example, both organs possess resident macrophages that play key roles in mediating the immune/inflammatory response. Additionally, alcohol-induced damage to both organs appears to involve oxidative stress that favors tissue injury. Another mechanism that appears to be shared between the organs is that inflammatory injury to both organs is enhanced by alcohol exposure. Lastly, altered extracellular matrix (ECM) deposition appears to be a key step in disease progression in both organs. Indeed, recent studies suggest that early subtle changes in the ECM may predispose the target organ to an inflammatory insult. The purpose of this chapter is to review the parallel mechanisms of liver and lung injury in response to alcohol consumption. This chapter will also explore the potential that these mechanisms are interdependent, as part of a gut-liver-lung axis. Full article
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Review
Impact of Alcohol on Glycemic Control and Insulin Action
by Jennifer L. Steiner, Kristen T. Crowell and Charles H. Lang
Biomolecules 2015, 5(4), 2223-2246; https://doi.org/10.3390/biom5042223 - 29 Sep 2015
Cited by 72 | Viewed by 15547
Abstract
Alcohol has profound effects on tissue and whole-body fuel metabolism which contribute to the increased morbidity and mortality in individuals with alcohol use disorder. This review focuses on the glucose metabolic effects of alcohol, primarily in the muscle, liver and adipose tissue, under [...] Read more.
Alcohol has profound effects on tissue and whole-body fuel metabolism which contribute to the increased morbidity and mortality in individuals with alcohol use disorder. This review focuses on the glucose metabolic effects of alcohol, primarily in the muscle, liver and adipose tissue, under basal postabsorptive conditions and in response to insulin stimulation. While there is a relatively extensive literature in this area, results are often discordant and extrapolating between models and tissues is fraught with uncertainty. Comparisons between data generated in experimental cell and animals systems will be contrasted with that obtained from human subjects as often times results differ. Further, the nutritional status is also an important component of the sometimes divergent findings pertaining to the effects of alcohol on the regulation of insulin and glucose metabolism. This work is relevant as the contribution of alcohol intake to the development or exacerbation of type 2 diabetes remains ill-defined and a multi-systems approach is likely needed as both alcohol and diabetes affect multiple targets within the body. Full article
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Review
The Altered Hepatic Tubulin Code in Alcoholic Liver Disease
by Jennifer L. Groebner and Pamela L. Tuma
Biomolecules 2015, 5(3), 2140-2159; https://doi.org/10.3390/biom5032140 - 18 Sep 2015
Cited by 16 | Viewed by 7148
Abstract
The molecular mechanisms that lead to the progression of alcoholic liver disease have been actively examined for decades. Because the hepatic microtubule cytoskeleton supports innumerable cellular processes, it has been the focus of many such mechanistic studies. It has long been appreciated that [...] Read more.
The molecular mechanisms that lead to the progression of alcoholic liver disease have been actively examined for decades. Because the hepatic microtubule cytoskeleton supports innumerable cellular processes, it has been the focus of many such mechanistic studies. It has long been appreciated that α-tubulin is a major target for modification by highly reactive ethanol metabolites and reactive oxygen species. It is also now apparent that alcohol exposure induces post-translational modifications that are part of the natural repertoire, mainly acetylation. In this review, the modifications of the “tubulin code” are described as well as those adducts by ethanol metabolites. The potential cellular consequences of microtubule modification are described with a focus on alcohol-induced defects in protein trafficking and enhanced steatosis. Possible mechanisms that can explain hepatic dysfunction are described and how this relates to the onset of liver injury is discussed. Finally, we propose that agents that alter the cellular acetylation state may represent a novel therapeutic strategy for treating liver disease. Full article
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Review
Alcoholic Liver Disease: Role of Cytokines
by Manuela G. Neuman, Yaakov Maor, Radu M. Nanau, Ehud Melzer, Haim Mell, Mihai Opris, Lawrence Cohen and Stephen Malnick
Biomolecules 2015, 5(3), 2023-2034; https://doi.org/10.3390/biom5032023 - 28 Aug 2015
Cited by 49 | Viewed by 6681
Abstract
The present review spans a broad spectrum of topics dealing with alcoholic liver disease (ALD), including clinical and translational research. It focuses on the role of the immune system and the signaling pathways of cytokines in the pathogenesis of ALD. An additional factor [...] Read more.
The present review spans a broad spectrum of topics dealing with alcoholic liver disease (ALD), including clinical and translational research. It focuses on the role of the immune system and the signaling pathways of cytokines in the pathogenesis of ALD. An additional factor that contributes to the pathogenesis of ALD is lipopolysaccharide (LPS), which plays a central role in the induction of steatosis, inflammation, and fibrosis in the liver. LPS derived from the intestinal microbiota enters the portal circulation, and is recognized by macrophages (Kupffer cells) and hepatocytes. In individuals with ALD, excessive levels of LPS in the liver affect immune, parenchymal, and non-immune cells, which in turn release various inflammatory cytokines and recruit neutrophils and other inflammatory cells. In this review, we elucidate the mechanisms by which alcohol contributes to the activation of Kupffer cells and the inflammatory cascade. The role of the stellate cells in fibrogenesis is also discussed. Full article
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Review
Biomolecules and Biomarkers Used in Diagnosis of Alcohol Drinking and in Monitoring Therapeutic Interventions
by Radu M. Nanau and Manuela G. Neuman
Biomolecules 2015, 5(3), 1339-1385; https://doi.org/10.3390/biom5031339 - 29 Jun 2015
Cited by 78 | Viewed by 14019
Abstract
Background: The quantitative, measurable detection of drinking is important for the successful treatment of alcohol misuse in transplantation of patients with alcohol disorders, people living with human immunodeficiency virus that need to adhere to medication, and special occupational hazard offenders, many of whom [...] Read more.
Background: The quantitative, measurable detection of drinking is important for the successful treatment of alcohol misuse in transplantation of patients with alcohol disorders, people living with human immunodeficiency virus that need to adhere to medication, and special occupational hazard offenders, many of whom continually deny drinking. Their initial misconduct usually leads to medical problems associated with drinking, impulsive social behavior, and drunk driving. The accurate identification of alcohol consumption via biochemical tests contributes significantly to the monitoring of drinking behavior. Methods: A systematic review of the current methods used to measure biomarkers of alcohol consumption was conducted using PubMed and Google Scholar databases (2010–2015). The names of the tests have been identified. The methods and publications that correlate between the social instruments and the biochemical tests were further investigated. There is a clear need for assays standardization to ensure the use of these biochemical tests as routine biomarkers. Findings: Alcohol ingestion can be measured using a breath test. Because alcohol is rapidly eliminated from the circulation, the time for detection by this analysis is in the range of hours. Alcohol consumption can alternatively be detected by direct measurement of ethanol concentration in blood or urine. Several markers have been proposed to extend the interval and sensitivities of detection, including ethyl glucuronide and ethyl sulfate in urine, phosphatidylethanol in blood, and ethyl glucuronide and fatty acid ethyl esters in hair, among others. Moreover, there is a need to correlate the indirect biomarker carbohydrate deficient transferrin, which reflects longer lasting consumption of higher amounts of alcohol, with serum γ-glutamyl transpeptidase, another long term indirect biomarker that is routinely used and standardized in laboratory medicine. Full article
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Review
Advances and New Concepts in Alcohol-Induced Organelle Stress, Unfolded Protein Responses and Organ Damage
by Cheng Ji
Biomolecules 2015, 5(2), 1099-1121; https://doi.org/10.3390/biom5021099 - 03 Jun 2015
Cited by 42 | Viewed by 10340
Abstract
Alcohol is a simple and consumable biomolecule yet its excessive consumption disturbs numerous biological pathways damaging nearly all organs of the human body. One of the essential biological processes affected by the harmful effects of alcohol is proteostasis, which regulates the balance between [...] Read more.
Alcohol is a simple and consumable biomolecule yet its excessive consumption disturbs numerous biological pathways damaging nearly all organs of the human body. One of the essential biological processes affected by the harmful effects of alcohol is proteostasis, which regulates the balance between biogenesis and turnover of proteins within and outside the cell. A significant amount of published evidence indicates that alcohol and its metabolites directly or indirectly interfere with protein homeostasis in the endoplasmic reticulum (ER) causing an accumulation of unfolded or misfolded proteins, which triggers the unfolded protein response (UPR) leading to either restoration of homeostasis or cell death, inflammation and other pathologies under severe and chronic alcohol conditions. The UPR senses the abnormal protein accumulation and activates transcription factors that regulate nuclear transcription of genes related to ER function. Similarly, this kind of protein stress response can occur in other cellular organelles, which is an evolving field of interest. Here, I review recent advances in the alcohol-induced ER stress response as well as discuss new concepts on alcohol-induced mitochondrial, Golgi and lysosomal stress responses and injuries. Full article
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Article
The Effect of Alcohol and Hydrogen Peroxide on Liver Hepcidin Gene Expression in Mice Lacking Antioxidant Enzymes, Glutathione Peroxidase-1 or Catalase
by Duygu Dee Harrison-Findik and Sizhao Lu
Biomolecules 2015, 5(2), 793-807; https://doi.org/10.3390/biom5020793 - 06 May 2015
Cited by 22 | Viewed by 9723
Abstract
This study investigates the regulation of hepcidin, the key iron-regulatory molecule, by alcohol and hydrogen peroxide (H2O2) in glutathione peroxidase-1 (gpx-1−/−) and catalase (catalase−/−) knockout mice. For alcohol studies, 10% ethanol was administered in the [...] Read more.
This study investigates the regulation of hepcidin, the key iron-regulatory molecule, by alcohol and hydrogen peroxide (H2O2) in glutathione peroxidase-1 (gpx-1−/−) and catalase (catalase−/−) knockout mice. For alcohol studies, 10% ethanol was administered in the drinking water for 7 days. Gpx-1−/− displayed significantly higher hepatic H2O2 levels than catalase−/− compared to wild-type mice, as measured by 2'-7'-dichlorodihydrofluorescein diacetate (DCFH-DA). The basal level of liver hepcidin expression was attenuated in gpx-1−/− mice. Alcohol increased H2O2 production in catalase−/− and wild-type, but not gpx-1−/−, mice. Hepcidin expression was inhibited in alcohol-fed catalase−/− and wild-type mice. In contrast, alcohol elevated hepcidin expression in gpx-1−/− mice. Gpx-1−/− mice also displayed higher level of basal liver CHOP protein expression than catalase−/− mice. Alcohol induced CHOP and to a lesser extent GRP78/BiP expression, but not XBP1 splicing or binding of CREBH to hepcidin gene promoter, in gpx-1−/− mice. The up-regulation of hepatic ATF4 mRNA levels, which was observed in gpx-1−/− mice, was attenuated by alcohol. In conclusion, our findings strongly suggest that H2O2 inhibits hepcidin expression in vivo. Synergistic induction of CHOP by alcohol and H2O2, in the absence of gpx-1, stimulates liver hepcidin gene expression by ER stress independent of CREBH. Full article
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