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Kouroumalis E, Tsomidis I, Voumvouraki A. Iron as a therapeutic target in chronic liver disease. World J Gastroenterol 2023; 29:616-655. [PMID: 36742167 PMCID: PMC9896614 DOI: 10.3748/wjg.v29.i4.616] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/02/2022] [Revised: 11/03/2022] [Accepted: 12/31/2022] [Indexed: 01/20/2023] Open
Abstract
It was clearly realized more than 50 years ago that iron deposition in the liver may be a critical factor in the development and progression of liver disease. The recent clarification of ferroptosis as a specific form of regulated hepatocyte death different from apoptosis and the description of ferritinophagy as a specific variation of autophagy prompted detailed investigations on the association of iron and the liver. In this review, we will present a brief discussion of iron absorption and handling by the liver with emphasis on the role of liver macrophages and the significance of the iron regulators hepcidin, transferrin, and ferritin in iron homeostasis. The regulation of ferroptosis by endogenous and exogenous mod-ulators will be examined. Furthermore, the involvement of iron and ferroptosis in various liver diseases including alcoholic and non-alcoholic liver disease, chronic hepatitis B and C, liver fibrosis, and hepatocellular carcinoma (HCC) will be analyzed. Finally, experimental and clinical results following interventions to reduce iron deposition and the promising manipulation of ferroptosis will be presented. Most liver diseases will be benefited by ferroptosis inhibition using exogenous inhibitors with the notable exception of HCC, where induction of ferroptosis is the desired effect. Current evidence mostly stems from in vitro and in vivo experimental studies and the need for well-designed future clinical trials is warranted.
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Affiliation(s)
- Elias Kouroumalis
- Liver Research Laboratory, University of Crete Medical School, Heraklion 71003, Greece
| | - Ioannis Tsomidis
- First Department of Internal Medicine, AHEPA University Hospital, Thessaloniki 54621, Greece
| | - Argyro Voumvouraki
- First Department of Internal Medicine, AHEPA University Hospital, Thessaloniki 54621, Greece
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Dziembowska I, Wójcik M, Żekanowska E. Caffeine and alcohol - Friends or foes of human iron stores? J Trace Elem Med Biol 2022; 71:126922. [PMID: 35063815 DOI: 10.1016/j.jtemb.2022.126922] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/13/2021] [Revised: 12/06/2021] [Accepted: 01/03/2022] [Indexed: 02/07/2023]
Abstract
BACKGROUND & AIMS There is clear evidence that lifestyle factors affect iron bioavailability. However, information regarding the effect of alcohol and caffeine consumption on iron metabolism is limited. The aim of the current study was to evaluate the effect of caffeine and alcohol consumption on iron metabolism in healthy men, regarding their everyday physical activity level. METHODS The study enrolled 83 men (59 physically active and 24 sedentary men) aged 18-32 years. Fasting blood samples were collected. ELISA kits were used to determine levels of ferritin, soluble transferrin receptor, hepcidin, hemojuvelin, and C-reactive protein (hsCRP). Level of physical activity was assessed using the International Physical Activity Questionnaire (IPAQ). Caffeine and alcohol intake was assessed using a food frequency questionnaire. A general linear model was performed to evaluate the relationship between caffeine intake and levels of serum ferritin, ferritin, soluble transferrin receptor, hepcidin, hemojuvelin, and hsCRP. RESULTS Physically active men (but not sedentary men) who consumed alcohol in excess presented higher ferritin levels when compared to moderate drinkers and abstainers (R2 = 0.35, p = 0.0001). Heavy drinkers presented the highest hepcidin levels when compared to both abstainers and moderate drinkers (p < 0.0001 for physically active, and p = 0.0267 for sedentary men). However, moderate drinkers showed significantly lower hsCRP levels when compared to heavy drinkers and abstainers drinkers (p < 0.0001 for physically active, and p = 0.0116 for sedentary men). Greater caffeine intake was generally associated with greater serum hepcidin levels, with the strongest effect on moderate drinkers. A significant influence of caffeine intake on hsCRP was shown for physically active men but not for sedentary men - greater caffeine intake was connected with higher hsCRP levels for participants who drank alcohol. CONCLUSION Based on the presented results it can be assumed that high caffeine consumption may lead to suppression of iron bioavailability through increased inflammation. Furthermore, physical activity and moderate alcohol consumption seemed to benefit reduction of inflammatory response, at least as represented by hsCRP levels.
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Affiliation(s)
- Inga Dziembowska
- Department of Pathophysiology, Faculty of Pharmacy, Ludwik Rydygier Collegium Medicum in Bydgoszcz, Nicolaus Copernicus University in Toruń, Skłodowskiej-Curie 9, 85-094, Bydgoszcz, Poland.
| | - Małgorzata Wójcik
- Institute of Health Science, Department Physiotherapy, University of Applied Sciences in Gniezno, Poland
| | - Ewa Żekanowska
- Department of Pathophysiology, Faculty of Pharmacy, Ludwik Rydygier Collegium Medicum in Bydgoszcz, Nicolaus Copernicus University in Toruń, Skłodowskiej-Curie 9, 85-094, Bydgoszcz, Poland
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Li LX, Guo FF, Liu H, Zeng T. Iron overload in alcoholic liver disease: underlying mechanisms, detrimental effects, and potential therapeutic targets. Cell Mol Life Sci 2022; 79:201. [PMID: 35325321 PMCID: PMC11071846 DOI: 10.1007/s00018-022-04239-9] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2022] [Revised: 03/04/2022] [Accepted: 03/09/2022] [Indexed: 02/06/2023]
Abstract
Alcoholic liver disease (ALD) is a global public health challenge due to the high incidence and lack of effective therapeutics. Evidence from animal studies and ALD patients has demonstrated that iron overload is a hallmark of ALD. Ethanol exposure can promote iron absorption by downregulating the hepcidin expression, which is probably mediated by inducing oxidative stress and promoting erythropoietin (EPO) production. In addition, ethanol may enhance iron uptake in hepatocytes by upregulating the expression of transferrin receptor (TfR). Iron overload in the liver can aggravate ethanol-elicited liver damage by potentiating oxidative stress via Fenton reaction, promoting activation of Kupffer cells (KCs) and hepatic stellate cells (HSCs), and inducing a recently discovered programmed iron-dependent cell death, ferroptosis. This article reviews the current knowledge of iron metabolism, regulators of iron homeostasis, the mechanism of ethanol-induced iron overload, detrimental effects of iron overload in the liver, and potential therapeutic targets.
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Affiliation(s)
- Long-Xia Li
- Institute of Toxicology, School of Public Health, Cheeloo College of Medicine, Shandong University, Jinan, 250012, Shandong, China
| | - Fang-Fang Guo
- Department of Pharmacy, Qilu Hospital, Cheeloo College of Medicine, Shandong University, Jinan, 250012, Shandong, China
| | - Hong Liu
- Institute of Toxicology, School of Public Health, Cheeloo College of Medicine, Shandong University, Jinan, 250012, Shandong, China
| | - Tao Zeng
- Institute of Toxicology, School of Public Health, Cheeloo College of Medicine, Shandong University, Jinan, 250012, Shandong, China.
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Yu LN, Wang SJ, Chen C, Rausch V, Elshaarawy O, Mueller S. Direct modulation of hepatocyte hepcidin signaling by iron. World J Hepatol 2021; 13:1378-1393. [PMID: 34786173 PMCID: PMC8568584 DOI: 10.4254/wjh.v13.i10.1378] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/27/2021] [Revised: 05/04/2021] [Accepted: 08/27/2021] [Indexed: 02/06/2023] Open
Abstract
BACKGROUND Liver-secreted hepcidin is the systemic master switch of iron homeostasis and decreased levels of hepcidin are considered to cause iron overload not only in hereditary hemochromatosis but also in hemolytic anemia and chronic liver diseases. The regulation of hepcidin is complex and its response to iron is still not completely understood.
AIM To study the direct effect of iron on various established hepcidin signaling pathways in hepatoma cells or primary hepatocytes.
METHODS Hepcidin mRNA expression was studied by quantitative real-time (qRT)-PCR in the presence of various forms of iron including ferric ammonium citrate (FAC) in hepatoma cells (Huh7), murine primary hepatocytes and an established co-culture model of phorbol myristate acetate-differentiated THP-1 monocytes and Huh7 cells. To analyze hepcidin signaling, the response to bone morphogenetic protein 6 (BMP6), interleukin (IL)-6, IL-1β, hypoxia and lipopolysaccharide (LPS) were studied. Hepcidin and small mothers against decapentaplegic 6 (SMAD6) mRNA levels were assessed by qRT-PCR and the expression of phosphorylated signal transducer and activator of transcription 3 (phospho-STAT3), STAT3, phospho-SMAD1/5/8 and SMAD1 proteins were analyzed by western blot.
RESULTS All iron III forms including FAC efficiently blocked hepcidin mRNA expression at non-toxic dosages in Huh7 cells or primary hepatocytes in a time and dose-dependent manner (P < 0.001; P < 0.05). Hepcidin blockage could be efficiently blunted by iron chelators salicylaldehyde isonicotinoyl hydrazone (SIH) and Desferal (P < 0.001). FAC also inhibited BMP6, hypoxia, IL-1β and IL-6-mediated hepcidin induction (P < 0.001; P < 0.001; P < 0.05; P < 0.001), and FAC also inhibited LPS-mediated hepatic hepcidin induction in co-culture model (P < 0.001). Moreover, FAC reduced SMAD6 mRNA and p-SMAD1/5/8 protein expression at basal or upon stimulation by BMP6 (P < 0.05; P < 0.01), and FAC also reduced SMAD6 and p-SMAD1/5/8 expression under hypoxia (P < 0.01; P < 0.05). However, FAC has no significant effect on p-STAT3 protein expression at basal or upon stimulation by various stimuli. Notably, in the presence of the BMP/SMAD signaling pathway inhibitor LDN193189 Hydrochloride (LDN), FAC was unable to further decrease hepcidin, SMAD6 and p-SMAD1/5/8 expression compared with LDN alone.
CONCLUSION Iron directly blocks hepatocellular hepcidin signaling through the BMP/SMAD pathway but independent of STAT3. This mechanism may contribute to continued iron overload in many pathophysiological conditions ultimately causing a vicious cycle of continued hepcidin suppression.
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Affiliation(s)
- Lin-Na Yu
- Center for Alcohol Research and Salem Medical Center, University of Heidelberg, Heidelberg 69121, Germany
| | - Shi-Jin Wang
- Center for Alcohol Research and Salem Medical Center, University of Heidelberg, Heidelberg 69121, Germany
| | - Cheng Chen
- Center for Alcohol Research and Salem Medical Center, University of Heidelberg, Heidelberg 69121, Germany
| | - Vanessa Rausch
- Center for Alcohol Research and Salem Medical Center, University of Heidelberg, Heidelberg 69121, Germany
| | - Omar Elshaarawy
- Department of Hepatology, Gastroenterology and Liver Transplantation, National Liver Institute, Menoufia University, Shebine Elkom 35121, El Salvador
- Department of Gastroenterology, Royal Liverpool University Hospital, Liverpool L7 8XP, United Kingdom
| | - Sebastian Mueller
- Center for Alcohol Research and Salem Medical Center, University of Heidelberg, Heidelberg 69121, Germany
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Bloomer SA, Moyer ED, Brown KE, Kregel KC. Aging results in accumulation of M1 and M2 hepatic macrophages and a differential response to gadolinium chloride. Histochem Cell Biol 2019; 153:37-48. [PMID: 31691025 DOI: 10.1007/s00418-019-01827-y] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 10/25/2019] [Indexed: 02/06/2023]
Abstract
Macrophages have vital roles in innate immunity by modulating the inflammatory response via their ability to alter their phenotype from pro-inflammatory (M1) to anti-inflammatory (M2). Aging increases activation of the innate immune system, and macrophage numbers increase in the aged liver. Since macrophages also produce free radical molecules, they are a potential source of age-related oxidative injury in the liver. This study evaluated macrophage phenotype in the aged liver and whether the increase in the number of macrophages with aging is associated with enhanced hepatic oxidative stress. Hepatic macrophage phenotype and oxidative stress were evaluated 2 days after a single intraperitoneal injection of saline or gadolinium chloride (GdCl3, 10 mg/kg) in young (6 months) and aged (24 months) Fischer 344 rats. GdCl3 has been shown to decrease the expression of macrophage-specific markers and impair macrophage phagocytosis in the liver. Saline-treated aged rats demonstrated greater numbers of both M1 (HO-1+/iNOS+) and M2 (HO-1+/CD163+) macrophages, without evidence of a phenotypic shift. GdCl3 did not alter levels of dihydroethidium fluorescence or malondialdehyde, suggesting that macrophages are not a major contributor to steady-state levels of oxidative stress. However, GdCl3 decreased M1 and M2 macrophage markers in both age groups, an effect that was attenuated in aged rats. In old animals, GdCl3 decreased iNOS expression to a greater extent than HO-1 or CD163. These results suggest a novel effect of aging on macrophage biology and that GdCl3 shifts hepatic macrophage polarization to the M2 phenotype in aged animals.
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Affiliation(s)
- Steven A Bloomer
- Division of Science and Engineering, Penn State University, Abington College, 1600 Woodland Rd., Abington, PA, 19001, USA.
| | - Eric D Moyer
- Division of Science and Engineering, Penn State University, Abington College, 1600 Woodland Rd., Abington, PA, 19001, USA
| | - Kyle E Brown
- Iowa City Veterans Administration Medical Center, Iowa City, IA, 52242, USA.,Division of Gastroenterology-Hepatology, University of Iowa Roy J. and Lucille A. Carver College of Medicine, Iowa City, IA, 52242, USA.,Program in Free Radical and Radiation Biology, University of Iowa Roy J. and Lucille A. Carver College of Medicine, Iowa City, IA, 52242, USA
| | - Kevin C Kregel
- Department of Health and Human Physiology, The University of Iowa, Iowa City, IA, 52242, USA
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Helfrich KK, Saini N, Kling PJ, Smith SM. Maternal iron nutriture as a critical modulator of fetal alcohol spectrum disorder risk in alcohol-exposed pregnancies. Biochem Cell Biol 2018; 96:204-212. [PMID: 29017023 PMCID: PMC5914169 DOI: 10.1139/bcb-2017-0206] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
Alcohol consumption during pregnancy places the fetus at risk for permanent physical, cognitive, and behavioral impairments, collectively termed fetal alcohol spectrum disorder (FASD). However, prenatal alcohol exposure (PAE) outcomes vary widely, and growing evidence suggests that maternal nutrition is a modifying factor. Certain nutrients, such as iron, may modulate FASD outcomes. Untreated gestational iron deficiency (ID) causes persistent neurodevelopmental deficits in the offspring that affect many of the same domains damaged by PAE. Although chronic alcohol consumption enhances iron uptake and elevates liver iron stores in adult alcoholics, alcohol-abusing premenopausal women often have low iron reserves due to menstruation, childbirth, and poor diet. Recent investigations show that low iron reserves during pregnancy are strongly associated with a worsening of several hallmark features in FASD including reduced growth and impaired associative learning. This review discusses recent clinical and animal model findings that maternal ID worsens fetal outcomes in response to PAE. It also discusses underlying mechanisms by which PAE disrupts maternal and fetal iron homeostasis. We suggest that alcohol-exposed ID pregnancies contribute to the severe end of the FASD spectrum.
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Affiliation(s)
- Kaylee K Helfrich
- a UNC Nutrition Research Institute and Department of Nutrition, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA
| | - Nipun Saini
- a UNC Nutrition Research Institute and Department of Nutrition, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA
| | - Pamela J Kling
- b Department of Pediatrics, University of Wisconsin-Madison, Madison, WI 53706, USA
| | - Susan M Smith
- a UNC Nutrition Research Institute and Department of Nutrition, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA
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7
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Vela D. Low hepcidin in liver fibrosis and cirrhosis; a tale of progressive disorder and a case for a new biochemical marker. Mol Med 2018; 24:5. [PMID: 30134796 PMCID: PMC6016890 DOI: 10.1186/s10020-018-0008-7] [Citation(s) in RCA: 27] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2018] [Accepted: 02/13/2018] [Indexed: 02/06/2023] Open
Abstract
Liver fibrosis is a precursor of liver cirrhosis, which is associated with increased mortality. Though liver biopsy remains the gold standard for the diagnosis of fibrosis, noninvasive biochemical methods are cost-effective, practical and are not linked with major risks of complications. In this respect, serum hepcidin, has emerged as a new marker of fibrosis and cirrhosis. In this review the discussion uncovers molecular links between hepcidin disturbance and liver fibrosis/cirrhosis. The discussion also expands on clinical studies that suggest that hepcidin can potentially be used as a biochemical parameter of fibrosis/cirrhosis and target of therapeutic strategies to treat liver diseases. The debatable issues such as the complicated nature of hepcidin disturbance in non-alcoholic liver disease, serum levels of hepcidin in acute hepatitis C virus infection, cause of hepcidin disturbance in autoimmune hepatitis and hepatic insulin resistance are discussed, with potential solutions unveiled in order to be studied by future research.
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Affiliation(s)
- Driton Vela
- Department of Physiology, Faculty of Medicine, University of Prishtina, Martyr's Boulevard n.n, Prishtina, 10000, Kosovo.
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8
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Harrison-Findik DD, Lu S. The effect of alcohol and hydrogen peroxide on liver hepcidin gene expression in mice lacking antioxidant enzymes, glutathione peroxidase-1 or catalase. Biomolecules 2015; 5:793-807. [PMID: 25955433 PMCID: PMC4496697 DOI: 10.3390/biom5020793] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2015] [Revised: 04/22/2015] [Accepted: 04/27/2015] [Indexed: 01/04/2023] Open
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 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.
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Affiliation(s)
- Duygu Dee Harrison-Findik
- Department of Internal Medicine, Division of Gastroenterology/Hepatology, University of Nebraska Medical Center, Omaha, NE 68198, USA.
| | - Sizhao Lu
- Department of Biochemistry and Molecular Biology, University of Nebraska Medical Center, Omaha, NE 68198, USA.
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The role of iron in alcohol-mediated hepatocarcinogenesis. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2015; 815:89-112. [PMID: 25427903 DOI: 10.1007/978-3-319-09614-8_6] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Alcoholic liver disease (ALD) is the major liver disease in the developed world and characterized by hepatic iron overload in ca. 50% of all patients. This iron overload is an independent factor of disease progression, hepatocellular carcinoma and it determines survival. Since simple phlebotomy does not allow the efficient removal of excess iron in ALD, a better understanding of the underlying mechanisms is urgently needed to identify novel targeted treatment strategies. This review summarizes the present knowledge on iron overload in patients with ALD. Although multiple sides of the cellular and systemic iron homeostasis may be affected during alcohol consumption, most studies have focused on potential hepatic causes. However, it should not be overlooked that more than 90% of the major iron pool, the hemoglobin-associated iron, is efficiently recycled within the human body and it is also strongly affected by alcohol. The few available studies suggest various molecular mechanisms that involve iron regulatory protein (IRP1), transferrin receptor 1 (TfR1), and the systemic iron master switch hepcidin, but not classical mutations of the HFE gene. Notably, reactive oxygen species (ROS), namely, hydrogen peroxide (H2O2), are powerful modulators of these iron-steering proteins. For instance, depending on the level, H2O2 may both strongly suppress and induce the expression of hepcidin that could partly explain the anemia and iron overload observed in these patients. More studies with appropriate ROS models such as the novel GOX/CAT system are required to unravel the mechanisms of iron overload in ALD to consequently identify molecular-targeted therapies in the future.
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Williams JA, Manley S, Ding WX. New advances in molecular mechanisms and emerging therapeutic targets in alcoholic liver diseases. World J Gastroenterol 2014; 20:12908-12933. [PMID: 25278688 PMCID: PMC4177473 DOI: 10.3748/wjg.v20.i36.12908] [Citation(s) in RCA: 70] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/17/2013] [Revised: 03/07/2014] [Accepted: 04/16/2014] [Indexed: 02/06/2023] Open
Abstract
Alcoholic liver disease is a major health problem in the United States and worldwide. Chronic alcohol consumption can cause steatosis, inflammation, fibrosis, cirrhosis and even liver cancer. Significant progress has been made to understand key events and molecular players for the onset and progression of alcoholic liver disease from both experimental and clinical alcohol studies. No successful treatments are currently available for treating alcoholic liver disease; therefore, development of novel pathophysiological-targeted therapies is urgently needed. This review summarizes the recent progress on animal models used to study alcoholic liver disease and the detrimental factors that contribute to alcoholic liver disease pathogenesis including miRNAs, S-adenosylmethionine, Zinc deficiency, cytosolic lipin-1β, IRF3-mediated apoptosis, RIP3-mediated necrosis and hepcidin. In addition, we summarize emerging adaptive protective effects induced by alcohol to attenuate alcohol-induced liver pathogenesis including FoxO3, IL-22, autophagy and nuclear lipin-1α.
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Harrison-Findik DD, Lu S, Zmijewski EM, Jones J, Zimmerman MC. Effect of alcohol exposure on hepatic superoxide generation and hepcidin expression. World J Biol Chem 2013; 4:119-130. [PMID: 24340135 PMCID: PMC3856307 DOI: 10.4331/wjbc.v4.i4.119] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/21/2013] [Revised: 10/03/2013] [Accepted: 11/16/2013] [Indexed: 02/05/2023] Open
Abstract
AIM: To understand the role of mitochondrial-produced superoxide (O2•-) in the regulation of iron-regulatory hormone, hepcidin by alcohol in the liver.
METHODS: For alcohol experiments, manganese superoxide dismutase knockout mice heterozygous for Sod2 gene expression (Sod2+/-) and age-matched littermate control mice (LMC), expressing Sod2 gene on both alleles, were exposed to either 10% (w/v) ethanol in the drinking water or plain water (control) for 7 d. Total cellular O2•- levels in hepatocytes isolated from the livers of mice were measured by electron paramagnetic resonance spectroscopy. The mitochondrial-targeted, O2•--sensitive fluorogenic probe, MitoSOX Red and flow cytometry were utilized to measure O2•- in mitochondria. Gene and protein expression were determined by Taqman Real-time quantitative PCR and Western blotting, respectively.
RESULTS: Sod2+/- mice expressed 40% less MnSOD protein (SOD2) in hepatocytes compared to LMC mice. The deletion of Sod2 allele did not alter the basal expression level of hepcidin in the liver. 10% ethanol exposure for 1 wk inhibited hepatic hepcidin mRNA expression three-fold both in Sod2+/- and LMC mice. O2•- levels in hepatocytes of untreated Sod2+/- mice were three-fold higher than in untreated LMC mice, as observed by electron paramagnetic resonance spectroscopy. O2•- levels in mitochondria of Sod2+/ mice were four-fold higher than in mitochondria of untreated LMC mice, as measured by MitoSOX Red fluorescence and flow cytometry. Alcohol induced a two-fold higher increase in O2•- levels in hepatocytes of LMC mice than in Sod2+/- mice compared to respective untreated counterparts. In contrast, 1 wk alcohol exposure did not alter mitochondrial O2•- levels in both Sod2+/- and control mice.
CONCLUSION: Mitochondrial O2•- is not involved in the inhibition of liver hepcidin transcription and thereby regulation of iron metabolism by alcohol. These findings also suggest that short-term alcohol consumption significantly elevates O2•- levels in hepatocytes, which appears not to originate from mitochondria.
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Li Y, Deng Y, Tang Y, Yu H, Gao C, Liu L, Liu L, Yao P. Quercetin protects rat hepatocytes from oxidative damage induced by ethanol and iron by maintaining intercellular liable iron pool. Hum Exp Toxicol 2013; 33:534-41. [PMID: 23928830 DOI: 10.1177/0960327113499168] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
Accumulating evidence has shown that ethanol-induced iron overload plays a crucial role in the development and progression of alcoholic liver disease. We designed the present study to investigate the potential protective effect of quercetin, a naturally occurring iron-chelating antioxidant on alcoholic iron overload and oxidative stress. Ethanol-incubated (100 mmol/L) rat primary hepatocytes were co-treated by quercetin (100 µmol/L) and different dose of ferric nitrilotriacetate (Fe-NTA) for 24 h. When the hepatic enzyme releases in the culture medium, redox status of hepatocytes and the intercellular labile iron pool (LIP) level were assayed. Our data showed that Fe-NTA dose dependently induced cellular leakage of aspartate transaminase and lactate dehydrogenase, glutathione depletion, superoxide dismutase inactivation, and overproduction of malondialdehyde) and reactive oxygen species (ROS) of intact and especially ethanol-incubated hepatocytes. The oxidative damage resulted from ethanol, Fe-NTA, and especially their combined treatment was substantially alleviated by quercetin, accompanying the corresponding normalization of intercellular LIP level. Iron in excess, thus, may aggravate ethanol hepatotoxicity through Fenton-active LIP, and quercetin attenuated ethanol-induced iron and oxidative stress. To maintain intercellular LIP contributes to the hepatoprotective effect of quercetin besides its direct ROS-quenching activity.
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Affiliation(s)
- Y Li
- 1Department of Nutrition and Food Hygiene, School of Public Health, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, People's Republic of China
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Kim HG, Wang JH, Han JM, Hwang SY, Lee DS, Son CG. Chunggan Extract (CGX), A Traditional Korean Herbal Medicine, Exerts Hepatoprotective Effects in a Rat Model of Chronic Alcohol Consumption. Phytother Res 2013; 27:1854-62. [PMID: 23460575 DOI: 10.1002/ptr.4935] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2011] [Revised: 12/27/2012] [Accepted: 01/07/2013] [Indexed: 12/25/2022]
Affiliation(s)
- Hyeong Geug Kim
- Liver and Immunology Research Center; Daejeon Oriental Hospital of Oriental Medical Collage of Daejeon University; 22-5 Daehung-dong, Jung-gu Daejeon 301-724 Republic of Korea
| | - Jing Hua Wang
- Liver and Immunology Research Center; Daejeon Oriental Hospital of Oriental Medical Collage of Daejeon University; 22-5 Daehung-dong, Jung-gu Daejeon 301-724 Republic of Korea
| | - Jong Min Han
- Liver and Immunology Research Center; Daejeon Oriental Hospital of Oriental Medical Collage of Daejeon University; 22-5 Daehung-dong, Jung-gu Daejeon 301-724 Republic of Korea
| | - Seok Yeon Hwang
- Department of Biomedical Laboratory Science, College of Applied Science and Industry; Daejeon University; 96-3 Yongun-dong, Dong-gu Daejeon 300-716 Republic of Korea
| | - Dong Soo Lee
- Department of Internal Medicine, Daejeon St. Mary's Hospita; The Catholic University of Korea; Daejeon Republic of Korea
| | - Chang Gue Son
- Liver and Immunology Research Center; Daejeon Oriental Hospital of Oriental Medical Collage of Daejeon University; 22-5 Daehung-dong, Jung-gu Daejeon 301-724 Republic of Korea
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Liver hepcidin mRNA expression is inappropriately low in alcoholic patients compared with healthy controls. Eur J Gastroenterol Hepatol 2012; 24:1158-65. [PMID: 22732356 DOI: 10.1097/meg.0b013e328355cfd0] [Citation(s) in RCA: 44] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
BACKGROUND AND AIMS Hepcidin plays a crucial role in iron metabolism, preventing its absorption at the basolateral enterocyte membrane. Hepcidin regulation is complex and regulated at the transcriptional level. The relation between iron overload and alcoholic liver disease is well known, but its mechanism is not clear. We present an observational, case-control study, aimed at evaluating the effects of alcohol on the expression of hepcidin in human participants. We intended to assess whether iron overload related to alcohol ingestion was caused by hepcidin-impaired expression by determining hepcidin mRNA expression and relating it to iron stores, both in alcoholic patients and in normal controls. METHODS We compared liver hepcidin mRNA expression between 25 active drinkers with alcoholic liver disease, without cirrhosis, and 20 healthy controls. All individuals were evaluated for HFE mutations, complete blood count, coagulation, glucose, kidney function, liver function, viral hepatitis, C-reactive protein, interleukin 6, tumor necrosis factor α, and serum iron, ferritin, and transferrin saturation. Total RNA was isolated from liver samples, cDNA was obtained by reverse transcription, and hepatic expression levels of hepcidin were determined by real-time PCR using the comparative Ct method (2(-ΔΔCt)). RESULTS Serum ferritin and transferrin saturation were significantly higher in patients. Hepcidin was downregulated in patients compared with the controls by a mean factor of -0.44 (log10 2(-ΔΔCt)) (P=0.009). Hepcidin expression was not significantly different between the several grades of fibrosis, necroinflammatory activity, and liver iron stores. Heavy alcohol consumption caused the highest hepcidin mRNA suppression. The hepcidin mRNA expression/serum ferritin ratio was significantly lower in alcoholic patients (P<0.0001). CONCLUSION Hepcidin liver expression is inappropriately low in alcoholic patients with active alcoholism and preserved hepatic function, and we conclude that this is the mechanism for alcohol consumption-associated iron overload in humans.
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The hypoxia-inducible factor-C/EBPα axis controls ethanol-mediated hepcidin repression. Mol Cell Biol 2012; 32:4068-77. [PMID: 22869521 DOI: 10.1128/mcb.00723-12] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
Hepcidin is a liver-derived peptide hormone and the master regulator of systemic iron homeostasis. Decreased hepcidin expression is a common feature in alcoholic liver disease (ALD) and in mouse models of ethanol loading. Dysregulation of hepcidin signaling in ALD leads to liver iron deposition, which is a major contributing factor to liver injury. The mechanism by which hepcidin is regulated following ethanol treatment is unclear. An increase in liver hypoxia was observed in an acute ethanol-induced liver injury model. The hypoxic response is controlled by a family of hypoxia-inducible transcription factors (HIFs), which are composed of an oxygen-regulated alpha subunit (HIFα) and a constitutively present beta subunit, aryl hydrocarbon receptor nuclear translocator (HIFβ/Arnt). Disruption of liver HIF function reversed the repression of hepcidin following ethanol loading. Mouse models of liver HIF overexpression demonstrated that both HIF-1α and HIF-2α contribute to hepcidin repression in vivo. Ethanol treatment led to a decrease in CCAAT-enhancer-binding protein alpha (C/EBPα) protein expression in a HIF-dependent manner. Importantly, adenoviral rescue of C/EBPα in vivo ablated the hepcidin repression in response to ethanol treatment or HIF overexpression. These data provide novel insight into the regulation of hepcidin by hypoxia and indicate that targeting HIFs in the liver could be therapeutic in ALD.
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Alcohol Activates TGF-Beta but Inhibits BMP Receptor-Mediated Smad Signaling and Smad4 Binding to Hepcidin Promoter in the Liver. Int J Hepatol 2012; 2012:459278. [PMID: 22121494 PMCID: PMC3202137 DOI: 10.1155/2012/459278] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/28/2011] [Accepted: 08/07/2011] [Indexed: 02/07/2023] Open
Abstract
Hepcidin, a key regulator of iron metabolism, is activated by bone morphogenetic proteins (BMPs). Mice pair-fed with regular and ethanol-containing L. De Carli diets were employed to study the effect of alcohol on BMP signaling and hepcidin transcription in the liver. Alcohol induced steatosis and TGF-beta expression. Liver BMP2, but not BMP4 or BMP6, expression was significantly elevated. Despite increased BMP expression, the BMP receptor, and transcription factors, Smad1 and Smad5, were not activated. In contrast, alcohol stimulated Smad2 phosphorylation. However, Smad4 DNA-binding activity and the binding of Smad4 to hepcidin promoter were attenuated. In summary, alcohol stimulates TGF-beta and BMP2 expression, and Smad2 phosphorylation but inhibits BMP receptor, and Smad1 and Smad5 activation. Smad signaling pathway in the liver may therefore be involved in the regulation of hepcidin transcription and iron metabolism by alcohol. These findings may help to further understand the mechanisms of alcohol and iron-induced liver injury.
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Factors influencing disease phenotype and penetrance in HFE haemochromatosis. Hum Genet 2010; 128:233-48. [DOI: 10.1007/s00439-010-0852-1] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2010] [Accepted: 06/16/2010] [Indexed: 01/24/2023]
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Tumor necrosis factor-alpha promoter variants and iron phenotypes in 785 hemochromatosis and iron overload screening (HEIRS) study participants. Blood Cells Mol Dis 2010; 44:252-6. [PMID: 20178892 DOI: 10.1016/j.bcmd.2010.01.007] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2009] [Revised: 01/12/2010] [Accepted: 01/12/2010] [Indexed: 10/19/2022]
Abstract
We sought to determine if TNF promoter variants could explain iron phenotype heterogeneity in adults with previous HFE genotyping. HEIRS Study participants genotyped for C282Y and H63D were designated as high transferrin saturation (TS) and/or serum ferritin (SF) (high TS/SF), low TS/SF, or controls. We grouped 191 C282Y homozygotes as high TS/SF, low TS/SF, or controls, and 594 other participants by race/ethnicity as high TS/SF or controls. Using denaturing high-performance liquid chromatography (DHPLC), we screened the TNF promoter region in each participant. We performed multiple regression analyses in C282Y homozygotes using age, sex, HEIRS Study Field Center, and positivity for TNF -308G-->A and -238G-->A to determine if these attributes predicted ln TS or ln SF. DHPLC analyses were successful in 99.3% of 791 participants and detected 9 different variants; TNF -308G-->A and -238G-->A were the most prevalent. Most subjects positive for variants were heterozygous. The phenotype frequencies of each variant did not differ significantly (p<0.05) across subgroups of C282Y homozygotes, or across white, black, Hispanic, and Asian non-C282Y homozygotes subgrouped as high TS/SF phenotypes and controls. TNF -308G-->A positivity was a significant predictor of initial screening ln TS but not ln SF; TNF -238G-->A predicted neither ln TS nor ln SF. We conclude that TNF promoter variants have little, if any, effect on initial screening SF values in adults with or without C282Y homozygosity. We cannot exclude a possible association of homozygosity for TNF promoter variants on TS and SF values.
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Harrison-Findik DD. Is the iron regulatory hormone hepcidin a risk factor for alcoholic liver disease? World J Gastroenterol 2009; 15:1186-93. [PMID: 19291818 PMCID: PMC2658862 DOI: 10.3748/wjg.15.1186] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
Despite heavy consumption over a long period of time, only a small number of alcoholics develop alcoholic liver disease. This alludes to the possibility that other factors, besides alcohol, may be involved in the progression of the disease. Over the years, many such factors have indeed been identified, including iron. Despite being crucial for various important biological processes, iron can also be harmful due to its ability to catalyze Fenton chemistry. Alcohol and iron have been shown to interact synergistically to cause liver injury. Iron-mediated cell signaling has been reported to be involved in the pathogenesis of experimental alcoholic liver disease. Hepcidin is an iron-regulatory hormone synthesized by the liver, which plays a pivotal role in iron homeostasis. Both acute and chronic alcohol exposure suppress hepcidin expression in the liver. The sera of patients with alcoholic liver disease, particularly those exhibiting higher serum iron indices, have also been reported to display reduced prohepcidin levels. Alcohol-mediated oxidative stress is involved in the inhibition of hepcidin promoter activity and transcription in the liver. This in turn leads to an increase in intestinal iron transport and liver iron storage. Hepcidin is expressed primarily in hepatocytes. It is noteworthy that both hepatocytes and Kupffer cells are involved in the progression of alcoholic liver disease. However, the activation of Kupffer cells and TNF-α signaling has been reported not to be involved in the down-regulation of hepcidin expression by alcohol in the liver. Alcohol acts within the parenchymal cells of the liver to suppress the synthesis of hepcidin. Due to its crucial role in the regulation of body iron stores, hepcidin may act as a secondary risk factor in the progression of alcoholic liver disease. The clarification of the mechanisms by which alcohol disrupts iron homeostasis will allow for further understanding of the pathogenesis of alcoholic liver disease.
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