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Seitz HK, Moreira B, Neuman MG. Pathogenesis of Alcoholic Fatty Liver a Narrative Review. Life (Basel) 2023; 13:1662. [PMID: 37629519 PMCID: PMC10455719 DOI: 10.3390/life13081662] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2023] [Revised: 07/12/2023] [Accepted: 07/28/2023] [Indexed: 08/27/2023] Open
Abstract
Alcohol effect hepatic lipid metabolism through various mechanisms, leading synergistically to an accumulation of fatty acids (FA) and triglycerides. Obesity, as well as dietary fat (saturated fatty acids (FA) versus poly-unsaturated fatty acids (PUFA)) may modulate the hepatic fat. Alcohol inhibits adenosine monophosphate activated kinase (AMPK). AMPK activates peroxisome proliferator activated receptor a (PPARα) and leads to a decreased activation of sterol regulatory element binding protein 1c (SRABP1c). The inhibition of AMPK, and thus of PPARα, results in an inhibition of FA oxidation. This ß-oxidation is further reduced due to mitochondrial damage induced through cytochrome P4502E1 (CYP2E1)-driven oxidative stress. Furthermore, the synthesis of FAs is stimulated through an activation of SHREP1. In addition, alcohol consumption leads to a reduced production of adiponectin in adipocytes due to oxidative stress and to an increased mobilization of FAs from adipose tissue and from the gut as chylomicrons. On the other side, the secretion of FAs via very-low-density lipoproteins (VLDL) from the liver is inhibited by alcohol. Alcohol also affects signal pathways such as early growth response 1 (Egr-1) associated with the expression of tumour necrosis factor α (TNF α), and the mammalian target of rapamycin (mTOR) a key regulator of autophagy. Both have influence the pathogenesis of alcoholic fatty liver. Alcohol-induced gut dysbiosis contributes to the severity of ALD by increasing the metabolism of ethanol in the gut and promoting intestinal dysfunction. Moreover, pathogen-associated molecular patterns (PAMPS) via specific Toll-like receptor (TLR) bacterial overgrowth leads to the translocation of bacteria. Endotoxins and toxic ethanol metabolites enter the enterohepatic circulation, reaching the liver and inducing the activation of the nuclear factor kappa-B (NFκB) pathway. Pro-inflammatory cytokines released in the process contribute to inflammation and fibrosis. In addition, cellular apoptosis is inhibited in favour of necrosis.
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Affiliation(s)
- Helmut K. Seitz
- Centre of Liver and Alcohol Associated Diseases, Ethianum Clinic, Faculty of Medicine, University of Heidelberg, 69120 Heidelberg, Germany;
| | - Bernardo Moreira
- Centre of Liver and Alcohol Associated Diseases, Ethianum Clinic, Faculty of Medicine, University of Heidelberg, 69120 Heidelberg, Germany;
| | - Manuela G. Neuman
- In Vitro Drug Safety and Biotechnology, Department of Pharmacology and Toxicology, Temerity Faculty of Medicine, University of Toronto, Banting Institute, Toronto, ON M5G 1L5, Canada;
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Ruiz-Cortes K, Villageliu DN, Samuelson DR. Innate lymphocytes: Role in alcohol-induced immune dysfunction. Front Immunol 2022; 13:934617. [PMID: 36105802 PMCID: PMC9464604 DOI: 10.3389/fimmu.2022.934617] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2022] [Accepted: 07/25/2022] [Indexed: 11/13/2022] Open
Abstract
Alcohol use is known to alter the function of both innate and adaptive immune cells, such as neutrophils, macrophages, B cells, and T cells. Immune dysfunction has been associated with alcohol-induced end-organ damage. The role of innate lymphocytes in alcohol-associated pathogenesis has become a focus of research, as liver-resident natural killer (NK) cells were found to play an important role in alcohol-associated liver damage pathogenesis. Innate lymphocytes play a critical role in immunity and homeostasis; they are necessary for an optimal host response against insults including infections and cancer. However, the role of innate lymphocytes, including NK cells, natural killer T (NKT) cells, mucosal associated invariant T (MAIT) cells, gamma delta T cells, and innate lymphoid cells (ILCs) type 1–3, remains ill-defined in the context of alcohol-induced end-organ damage. Innate-like B lymphocytes including marginal zone B cells and B-1 cells have also been identified; however, this review will address the effects of alcohol misuse on innate T lymphocytes, as well as the consequences of innate T-lymphocyte dysfunction on alcohol-induced tissue damage.
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De Muynck K, Vanderborght B, Van Vlierberghe H, Devisscher L. The Gut-Liver Axis in Chronic Liver Disease: A Macrophage Perspective. Cells 2021; 10:2959. [PMID: 34831182 PMCID: PMC8616442 DOI: 10.3390/cells10112959] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2021] [Revised: 10/25/2021] [Accepted: 10/26/2021] [Indexed: 02/07/2023] Open
Abstract
Chronic liver disease (CLD) is a growing health concern which accounts for two million deaths per year. Obesity, alcohol overconsumption, and progressive cholestasis are commonly characterized by persistent low-grade inflammation and advancing fibrosis, which form the basis for development of end-stage liver disease complications, including hepatocellular carcinoma. CLD pathophysiology extends to the intestinal tract and is characterized by intestinal dysbiosis, bile acid dysregulation, and gut barrier disruption. In addition, macrophages are key players in CLD progression and intestinal barrier breakdown. Emerging studies are unveiling macrophage heterogeneity and driving factors of their plasticity in health and disease. To date, in-depth investigation of how gut-liver axis disruption impacts the hepatic and intestinal macrophage pool in CLD pathogenesis is scarce. In this review, we give an overview of the role of intestinal and hepatic macrophages in homeostasis and gut-liver axis disruption in progressive stages of CLD.
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Affiliation(s)
- Kevin De Muynck
- Gut-Liver Immunopharmacology Unit, Department of Basic and Applied Medical Sciences, Liver Research Center Ghent, Ghent University, 9000 Ghent, Belgium; (K.D.M.); (B.V.)
- Hepatology Research Unit, Department of Internal Medicine and Pediatrics, Liver Research Center Ghent, Ghent University, 9000 Ghent, Belgium;
| | - Bart Vanderborght
- Gut-Liver Immunopharmacology Unit, Department of Basic and Applied Medical Sciences, Liver Research Center Ghent, Ghent University, 9000 Ghent, Belgium; (K.D.M.); (B.V.)
- Hepatology Research Unit, Department of Internal Medicine and Pediatrics, Liver Research Center Ghent, Ghent University, 9000 Ghent, Belgium;
| | - Hans Van Vlierberghe
- Hepatology Research Unit, Department of Internal Medicine and Pediatrics, Liver Research Center Ghent, Ghent University, 9000 Ghent, Belgium;
| | - Lindsey Devisscher
- Gut-Liver Immunopharmacology Unit, Department of Basic and Applied Medical Sciences, Liver Research Center Ghent, Ghent University, 9000 Ghent, Belgium; (K.D.M.); (B.V.)
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Structural Insights in Mammalian Sialyltransferases and Fucosyltransferases: We Have Come a Long Way, but It Is Still a Long Way Down. Molecules 2021; 26:molecules26175203. [PMID: 34500643 PMCID: PMC8433944 DOI: 10.3390/molecules26175203] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2021] [Revised: 08/19/2021] [Accepted: 08/20/2021] [Indexed: 11/17/2022] Open
Abstract
Mammalian cell surfaces are modified with complex arrays of glycans that play major roles in health and disease. Abnormal glycosylation is a hallmark of cancer; terminal sialic acid and fucose in particular have high levels in tumor cells, with positive implications for malignancy. Increased sialylation and fucosylation are due to the upregulation of a set of sialyltransferases (STs) and fucosyltransferases (FUTs), which are potential drug targets in cancer. In the past, several advances in glycostructural biology have been made with the determination of crystal structures of several important STs and FUTs in mammals. Additionally, how the independent evolution of STs and FUTs occurred with a limited set of global folds and the diverse modular ability of catalytic domains toward substrates has been elucidated. This review highlights advances in the understanding of the structural architecture, substrate binding interactions, and catalysis of STs and FUTs in mammals. While this general understanding is emerging, use of this information to design inhibitors of STs and FUTs will be helpful in providing further insights into their role in the manifestation of cancer and developing targeted therapeutics in cancer.
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The role of sphingolipids in psychoactive drug use and addiction. J Neural Transm (Vienna) 2018; 125:651-672. [DOI: 10.1007/s00702-018-1840-1] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2017] [Accepted: 01/03/2018] [Indexed: 12/14/2022]
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Elamin E, Masclee A, Troost F, Dekker J, Jonkers D. Cytotoxicity and metabolic stress induced by acetaldehyde in human intestinal LS174T goblet-like cells. Am J Physiol Gastrointest Liver Physiol 2014; 307:G286-94. [PMID: 24904079 DOI: 10.1152/ajpgi.00103.2014] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
There is compelling evidence indicating that ethanol and its oxidative metabolite acetaldehyde can disrupt intestinal barrier function. Apart from the tight junctions, mucins secreted by goblet cells provide an effective barrier. Ethanol has been shown to induce goblet cell injury associated with alterations in mucin glycosylation. However, effects of its most injurious metabolite acetaldehyde remain largely unknown. This study aimed to assess short-term effects of acetaldehyde (0, 25, 50, 75, 100 μM) on functional characteristics of intestinal goblet-like cells (LS174T). Oxidative stress, mitochondrial function, ATP, and intramitochondrial calcium (Ca(2+)) were assessed by dichlorofluorescein, methyltetrazolium, and bioluminescence, MitoTracker green and rhod-2 double-labeling. Membrane integrity and apoptosis were evaluated by measuring lactate dehydrogenase (LDH), caspase 3/7, and cleavage of cytokeratin 18 (CK18). Expression of mucin 2 (MUC2) was determined by cell-based ELISA. Acetaldehyde significantly increased reactive oxygen species generation and decreased mitochondrial function compared with negative controls (P < 0.05). In addition, acetaldehyde dose-dependently decreased ATP levels and induced intramitochondrial Ca(2+) accumulation compared with negative controls (P < 0.05). Furthermore, acetaldehyde induced LDH release and increased caspase3/7 activity and percentage of cells expressing cleaved CK18 and increased MUC2 protein expression compared with negative controls (P < 0.0001). ATP depletion and LDH release could be largely prevented by the antioxidant N-acetylcysteine, suggesting a pivotal role for oxidative stress. Our data demonstrate that acetaldehyde has distinct oxidant-dependent metabolic and cytotoxic effects on LS174T cells that can lead to induction of cellular apoptosis. These effects may contribute to acetaldehyde-induced intestinal barrier dysfunction and subsequently to liver injury.
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Affiliation(s)
- Elhaseen Elamin
- Top Institute Food and Nutrition, Wageningen, the Netherlands; Division of Gastroenterology-Hepatology, Department of Internal Medicine, Maastricht University Medical Center, Maastricht, the Netherlands; School for Nutrition, Toxicology and Metabolism of Maastricht University Medical Center, Maastricht, the Netherlands; and
| | - Ad Masclee
- Top Institute Food and Nutrition, Wageningen, the Netherlands; Division of Gastroenterology-Hepatology, Department of Internal Medicine, Maastricht University Medical Center, Maastricht, the Netherlands; School for Nutrition, Toxicology and Metabolism of Maastricht University Medical Center, Maastricht, the Netherlands; and
| | - Freddy Troost
- Top Institute Food and Nutrition, Wageningen, the Netherlands; Division of Gastroenterology-Hepatology, Department of Internal Medicine, Maastricht University Medical Center, Maastricht, the Netherlands; School for Nutrition, Toxicology and Metabolism of Maastricht University Medical Center, Maastricht, the Netherlands; and
| | - Jan Dekker
- Top Institute Food and Nutrition, Wageningen, the Netherlands; Department of Animal Sciences, Wageningen UR, Wageningen, the Netherlands
| | - Daisy Jonkers
- Top Institute Food and Nutrition, Wageningen, the Netherlands; Division of Gastroenterology-Hepatology, Department of Internal Medicine, Maastricht University Medical Center, Maastricht, the Netherlands; School for Nutrition, Toxicology and Metabolism of Maastricht University Medical Center, Maastricht, the Netherlands; and
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