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Krylov D, Rodimova S, Karabut M, Kuznetsova D. Experimental Models for Studying Structural and Functional State of the Pathological Liver (Review). Sovrem Tekhnologii Med 2023; 15:65-82. [PMID: 38434194 PMCID: PMC10902899 DOI: 10.17691/stm2023.15.4.06] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2023] [Indexed: 03/05/2024] Open
Abstract
Liver pathologies remain one of the leading causes of mortality worldwide. Despite a high prevalence of liver diseases, the possibilities of diagnosing, prognosing, and treating non-alcoholic and alcoholic liver diseases still have a number of limitations and require the development of new methods and approaches. In laboratory studies, various models are used to reconstitute the pathological conditions of the liver, including cell cultures, spheroids, organoids, microfluidic systems, tissue slices. We reviewed the most commonly used in vivo, in vitro, and ex vivo models for studying non-alcoholic fatty liver disease and alcoholic liver disease, toxic liver injury, and fibrosis, described their advantages, limitations, and prospects for use. Great emphasis was placed on the mechanisms of development of pathological conditions in each model, as well as the assessment of the possibility of reconstructing various key aspects of pathogenesis for all these pathologies. There is currently no consensus on the choice of the most adequate model for studying liver pathology. The choice of a certain effective research model is determined by the specific purpose and objectives of the experiment.
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Affiliation(s)
- D.P. Krylov
- Laboratory Assistant, Scientific Laboratory of Molecular Biotechnologies, Research Institute of Experimental Oncology and Biomedical Technologies; Privolzhsky Research Medical University, 10/1 Minin and Pozharsky Square, Nizhny Novgorod, 603005, Russia; Student, Institute of Biology and Biomedicine; National Research Lobachevsky State University of Nizhny Novgorod, 23 Prospekt Gagarina, Nizhny Novgorod, 603022, Russia
| | - S.A. Rodimova
- Junior Researcher, Laboratory of Regenerative Medicine, Scientific Laboratory of Molecular Biotechnologies, Research Institute of Experimental Oncology and Biomedical Technologies; Privolzhsky Research Medical University, 10/1 Minin and Pozharsky Square, Nizhny Novgorod, 603005, Russia
| | - M.M. Karabut
- Researcher, Laboratory of Genomics of Adaptive Antitumor Immunity, Research Institute of Experimental Oncology and Biomedical Technologies; Privolzhsky Research Medical University, 10/1 Minin and Pozharsky Square, Nizhny Novgorod, 603005, Russia
| | - D.S. Kuznetsova
- Head of Laboratory of Molecular Biotechnologies, Research Institute of Experimental Oncology and Biomedical Technologies; Privolzhsky Research Medical University, 10/1 Minin and Pozharsky Square, Nizhny Novgorod, 603005, Russia; Head of the Research Laboratory for Molecular Genetic Researches, Institute of Clinical Medicine; National Research Lobachevsky State University of Nizhny Novgorod, 23 Prospekt Gagarina, Nizhny Novgorod, 603022, Russia
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2
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A Comparison of Primary Human Hepatocytes and Hepatoma Cell Lines to Model the Effects of Fatty Acids, Fructose and Glucose on Liver Cell Lipid Accumulation. Nutrients 2022; 15:nu15010040. [PMID: 36615698 PMCID: PMC9824391 DOI: 10.3390/nu15010040] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2022] [Revised: 12/14/2022] [Accepted: 12/19/2022] [Indexed: 12/24/2022] Open
Abstract
Non-alcoholic fatty liver disease (NAFLD) begins with lipid accumulation within hepatocytes, but the relative contributions of different macronutrients is still unclear. We investigated the impact of fatty acids, glucose and fructose on lipid accumulation in primary human hepatocytes (PHH) and three different cell lines: HepG2 (human hepatoblastoma−derived cell line), Huh7 (human hepatocellular carcinoma cell line) and McA-RH7777 (McA, rat hepatocellular carcinoma cell line). Cells were treated for 48 h with fatty acids (0 or 200 μM), glucose (5 mM or 11 mM) and fructose (0 mM, 2 mM or 8 mM). Lipid accumulation was measured via Nile Red staining. All cell types accumulated lipid in response to fatty acids (p < 0.001). PHH and McA, but not HepG2 or Huh7 cells, accumulated more lipid with 11 mM glucose plus fatty acids (p = 0.004, fatty acid × glucose interaction, for both), but only PHH increased lipid accumulation in response to fructose (p < 0.001). Considerable variation was observed between PHH cells from different individuals. Lipid accumulation in PHH was increased by insulin (p = 0.003) with inter-individual variability. Similarly, insulin increased lipid accumulation in both HepG2 and McA cells, with a bigger response in McA in the presence of fatty acids (p < 0.001 for fatty acid × insulin). McA were more insulin sensitive than either HepG2 or Huh7 cells in terms of AKT phosphorylation (p < 0.001 insulin × cell type interaction). Hence, glucose and fructose can contribute to the accumulation of lipid in PHH with considerable inter-individual variation, but hepatoma cell lines are not good models of PHH.
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Gatzios A, Rombaut M, Buyl K, De Kock J, Rodrigues RM, Rogiers V, Vanhaecke T, Boeckmans J. From NAFLD to MAFLD: Aligning Translational In Vitro Research to Clinical Insights. Biomedicines 2022; 10:biomedicines10010161. [PMID: 35052840 PMCID: PMC8773802 DOI: 10.3390/biomedicines10010161] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2021] [Revised: 01/09/2022] [Accepted: 01/10/2022] [Indexed: 11/16/2022] Open
Abstract
Although most same-stage non-alcoholic fatty liver disease (NAFLD) patients exhibit similar histologic sequelae, the underlying mechanisms appear to be highly heterogeneous. Therefore, it was recently proposed to redefine NAFLD to metabolic dysfunction-associated fatty liver disease (MAFLD) in which other known causes of liver disease such as alcohol consumption or viral hepatitis do not need to be excluded. Revised nomenclature envisions speeding up and facilitating anti-MAFLD drug development by means of patient stratification whereby each subgroup would benefit from distinct pharmacological interventions. As human-based in vitro research fulfils an irrefutable step in drug development, action should be taken as well in this stadium of the translational path. Indeed, most established in vitro NAFLD models rely on short-term exposure to fatty acids and use lipid accumulation as a phenotypic benchmark. This general approach to a seemingly ambiguous disease such as NAFLD therefore no longer seems applicable. Human-based in vitro models that accurately reflect distinct disease subgroups of MAFLD should thus be adopted in early preclinical disease modeling and drug testing. In this review article, we outline considerations for setting up translational in vitro experiments in the MAFLD era and allude to potential strategies to implement MAFLD heterogeneity into an in vitro setting so as to better align early drug development with future clinical trial designs.
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Affiliation(s)
| | | | | | | | | | | | | | - Joost Boeckmans
- Correspondence: (A.G.); (J.B.); Tel.: +32-(0)-2-477-45-94 (A.G.)
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4
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Alabi A, Xia XD, Gu HM, Wang F, Deng SJ, Yang N, Adijiang A, Douglas DN, Kneteman NM, Xue Y, Chen L, Qin S, Wang G, Zhang DW. Membrane type 1 matrix metalloproteinase promotes LDL receptor shedding and accelerates the development of atherosclerosis. Nat Commun 2021; 12:1889. [PMID: 33767172 PMCID: PMC7994674 DOI: 10.1038/s41467-021-22167-3] [Citation(s) in RCA: 26] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2019] [Accepted: 03/02/2021] [Indexed: 01/07/2023] Open
Abstract
Plasma low-density lipoprotein (LDL) is primarily cleared by LDL receptor (LDLR). LDLR can be proteolytically cleaved to release its soluble ectodomain (sLDLR) into extracellular milieu. However, the proteinase responsible for LDLR cleavage is unknown. Here we report that membrane type 1-matrix metalloproteinase (MT1-MMP) co-immunoprecipitates and co-localizes with LDLR and promotes LDLR cleavage. Plasma sLDLR and cholesterol levels are reduced while hepatic LDLR is increased in mice lacking hepatic MT1-MMP. Opposite effects are observed when MT1-MMP is overexpressed. MT1-MMP overexpression significantly increases atherosclerotic lesions, while MT1-MMP knockdown significantly reduces cholesteryl ester accumulation in the aortas of apolipoprotein E (apoE) knockout mice. Furthermore, sLDLR is associated with apoB and apoE-containing lipoproteins in mouse and human plasma. Plasma levels of sLDLR are significantly increased in subjects with high plasma LDL cholesterol levels. Thus, we demonstrate that MT1-MMP promotes ectodomain shedding of hepatic LDLR, thereby regulating plasma cholesterol levels and the development of atherosclerosis.
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Affiliation(s)
- Adekunle Alabi
- The Department of Pediatrics and Group on the Molecular and Cell Biology of Lipids, Faculty of Medicine and Dentistry, University of Alberta, Edmonton, AB, Canada
| | - Xiao-Dan Xia
- The Department of Pediatrics and Group on the Molecular and Cell Biology of Lipids, Faculty of Medicine and Dentistry, University of Alberta, Edmonton, AB, Canada.,Department of Orthopedics, The Sixth Affiliated Hospital of Guangzhou Medical University, Qingyuan People's Hospital, Qingyuan, China
| | - Hong-Mei Gu
- The Department of Pediatrics and Group on the Molecular and Cell Biology of Lipids, Faculty of Medicine and Dentistry, University of Alberta, Edmonton, AB, Canada
| | - Faqi Wang
- The Department of Pediatrics and Group on the Molecular and Cell Biology of Lipids, Faculty of Medicine and Dentistry, University of Alberta, Edmonton, AB, Canada
| | - Shi-Jun Deng
- The Department of Pediatrics and Group on the Molecular and Cell Biology of Lipids, Faculty of Medicine and Dentistry, University of Alberta, Edmonton, AB, Canada
| | - Nana Yang
- Experimental Center for Medical Research, Weifang Medical University, Weifang, China
| | - Ayinuer Adijiang
- The Department of Pediatrics and Group on the Molecular and Cell Biology of Lipids, Faculty of Medicine and Dentistry, University of Alberta, Edmonton, AB, Canada
| | - Donna N Douglas
- Department of Surgery, Faculty of Medicine and Dentistry, University of Alberta, Edmonton, AB, Canada
| | - Norman M Kneteman
- Department of Surgery, Faculty of Medicine and Dentistry, University of Alberta, Edmonton, AB, Canada
| | - Yazhuo Xue
- Institute of Atherosclerosis in Shandong First Medical University (Shandong Academy of Medical Sciences), Taian, China
| | - Li Chen
- Institute of Atherosclerosis in Shandong First Medical University (Shandong Academy of Medical Sciences), Taian, China
| | - Shucun Qin
- Institute of Atherosclerosis in Shandong First Medical University (Shandong Academy of Medical Sciences), Taian, China
| | - Guiqing Wang
- Department of Orthopedics, The Sixth Affiliated Hospital of Guangzhou Medical University, Qingyuan People's Hospital, Qingyuan, China
| | - Da-Wei Zhang
- The Department of Pediatrics and Group on the Molecular and Cell Biology of Lipids, Faculty of Medicine and Dentistry, University of Alberta, Edmonton, AB, Canada.
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Marine Fish Primary Hepatocyte Isolation and Culture: New Insights to Enzymatic Dissociation Pancreatin Digestion. INTERNATIONAL JOURNAL OF ENVIRONMENTAL RESEARCH AND PUBLIC HEALTH 2021; 18:ijerph18041380. [PMID: 33546159 PMCID: PMC7913162 DOI: 10.3390/ijerph18041380] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/31/2020] [Revised: 01/29/2021] [Accepted: 01/31/2021] [Indexed: 11/23/2022]
Abstract
Primary cell cultures from wild organisms have been gaining relevance in ecotoxicology as they are considered more sensitive than immortalized cell lines and retain the biochemical pathways found in vivo. In this study, the efficacy of two methods for primary hepatocyte cell isolation was compared using liver from two marine fish (Sparus aurata and Psetta maxima): (i) two-step collagenase perfusion and (ii) pancreatin digestion with modifications. Cell cultures were incubated in L-15 medium at 17 ± 1 °C and monitored for up to six days for cell viability and function using the trypan blue exclusion test, MTT test, lactate dehydrogenase (LDH) activity, and ethoxyresorufin O-deethylase (EROD) activity after Benzo[a]Pyrene exposure. The results showed significant differences between the number of viable cells (p < 0.05), the highest number being obtained for the pancreatin digestion method (average = 4.5 ± 1.9 × 107 cells). Moreover, the hepatocytes showed solid adherence to the culture plate and the rounded shape, changing into a triangular/polygonal shape. The cell viability and function obtained by pancreatin digestion were maintained for five days, and the EROD induction after exposure to the B[a]P showed that cells were metabolically active. This study shows that the optimized pancreatin digestion method is a valid, cost-effective, and simple alternative to the standard perfusion method for the isolation of primary hepatocytes from fish and is suitable for ecotoxicological studies involving marine pollutants, such as PAHs.
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Soret PA, Magusto J, Housset C, Gautheron J. In Vitro and In Vivo Models of Non-Alcoholic Fatty Liver Disease: A Critical Appraisal. J Clin Med 2020; 10:jcm10010036. [PMID: 33374435 PMCID: PMC7794936 DOI: 10.3390/jcm10010036] [Citation(s) in RCA: 68] [Impact Index Per Article: 17.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2020] [Revised: 12/22/2020] [Accepted: 12/23/2020] [Indexed: 02/07/2023] Open
Abstract
Non-alcoholic fatty liver disease (NAFLD), including non-alcoholic fatty liver (NAFL) and non-alcoholic steatohepatitis (NASH), represents the hepatic manifestation of obesity and metabolic syndrome. Due to the spread of the obesity epidemic, NAFLD is becoming the most common chronic liver disease and one of the principal indications for liver transplantation. However, no pharmacological treatment is currently approved to prevent the outbreak of NASH, which leads to fibrosis and cirrhosis. Preclinical research is required to improve our knowledge of NAFLD physiopathology and to identify new therapeutic targets. In the present review, we summarize advances in NAFLD preclinical models from cellular models, including new bioengineered platforms, to in vivo models, with a particular focus on genetic and dietary mouse models. We aim to discuss the advantages and limits of these different models.
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Affiliation(s)
- Pierre-Antoine Soret
- Centre de Recherche Saint-Antoine (CRSA), Sorbonne Université, Inserm, 75012 Paris, France; (P.-A.S.); (J.M.); (C.H.)
- Assistance Publique-Hôpitaux de Paris (AP-HP), Hepatology Department, Reference Center for Inflammatory Biliary Diseases and Autoimmune Hepatitis, Saint-Antoine Hospital, 75012 Paris, France
| | - Julie Magusto
- Centre de Recherche Saint-Antoine (CRSA), Sorbonne Université, Inserm, 75012 Paris, France; (P.-A.S.); (J.M.); (C.H.)
- Institute of Cardiometabolism and Nutrition (ICAN), Sorbonne Université, Inserm, AP-HP, 75013 Paris, France
| | - Chantal Housset
- Centre de Recherche Saint-Antoine (CRSA), Sorbonne Université, Inserm, 75012 Paris, France; (P.-A.S.); (J.M.); (C.H.)
- Assistance Publique-Hôpitaux de Paris (AP-HP), Hepatology Department, Reference Center for Inflammatory Biliary Diseases and Autoimmune Hepatitis, Saint-Antoine Hospital, 75012 Paris, France
- Institute of Cardiometabolism and Nutrition (ICAN), Sorbonne Université, Inserm, AP-HP, 75013 Paris, France
| | - Jérémie Gautheron
- Centre de Recherche Saint-Antoine (CRSA), Sorbonne Université, Inserm, 75012 Paris, France; (P.-A.S.); (J.M.); (C.H.)
- Institute of Cardiometabolism and Nutrition (ICAN), Sorbonne Université, Inserm, AP-HP, 75013 Paris, France
- Correspondence:
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7
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Aoudjehane L, Gautheron J, Le Goff W, Goumard C, Gilaizeau J, Nget CS, Savier E, Atif M, Lesnik P, Morichon R, Chrétien Y, Calmus Y, Scatton O, Housset C, Conti F. Novel defatting strategies reduce lipid accumulation in primary human culture models of liver steatosis. Dis Model Mech 2020; 13:dmm042663. [PMID: 32094147 PMCID: PMC7197711 DOI: 10.1242/dmm.042663] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2019] [Accepted: 02/13/2020] [Indexed: 12/13/2022] Open
Abstract
Normothermic perfusion provides a means to rescue steatotic liver grafts, including by pharmacological defatting. In this study, we tested the potential of new drug combinations to trigger defatting in three human culture models, primary hepatocytes with induced steatosis, primary hepatocytes isolated from steatotic liver, and precision-cut liver slices (PCLS) of steatotic liver. Forskolin, L-carnitine and a PPARα agonist were all combined with rapamycin, an immunosuppressant that induces autophagy, in a D-FAT cocktail. D-FAT was tested alone or in combination with necrosulfonamide, an inhibitor of mixed lineage kinase domain like pseudokinase involved in necroptosis. Within 24 h, in all three models, D-FAT induced a decrease in triglyceride content by 30%, attributable to an upregulation of genes involved in free fatty acid β-oxidation and autophagy, and a downregulation of those involved in lipogenesis. Defatting was accompanied by a decrease in endoplasmic reticulum stress and in the production of reactive oxygen species. The addition of necrosulfonamide increased the efficacy of defatting by 8%-12% in PCLS, with a trend towards increased autophagy. In conclusion, culture models, notably PCLS, are insightful to design strategies for liver graft rescue. Defatting can be rapidly achieved by combinations of drugs targeting mitochondrial oxidative metabolism, macro-autophagy and lipogenesis.
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Affiliation(s)
- Lynda Aoudjehane
- Institute of Cardiometabolism and Nutrition (ICAN), Sorbonne Université, INSERM, Paris 75012, France
- Centre de Recherche Saint-Antoine (CRSA), Sorbonne Université, INSERM, Paris 75013, France
| | - Jérémie Gautheron
- Institute of Cardiometabolism and Nutrition (ICAN), Sorbonne Université, INSERM, Paris 75012, France
- Centre de Recherche Saint-Antoine (CRSA), Sorbonne Université, INSERM, Paris 75013, France
| | - Wilfried Le Goff
- Institute of Cardiometabolism and Nutrition (ICAN), Sorbonne Université, INSERM, Paris 75012, France
| | - Claire Goumard
- Institute of Cardiometabolism and Nutrition (ICAN), Sorbonne Université, INSERM, Paris 75012, France
- Centre de Recherche Saint-Antoine (CRSA), Sorbonne Université, INSERM, Paris 75013, France
- Department of Hepatobiliary and Liver Transplantation Surgery, Pitié-Salpêtrière Hospital, Assistance Publique-Hôpitaux de Paris, Paris 75013, France
| | - Julia Gilaizeau
- Institute of Cardiometabolism and Nutrition (ICAN), Sorbonne Université, INSERM, Paris 75012, France
- Centre de Recherche Saint-Antoine (CRSA), Sorbonne Université, INSERM, Paris 75013, France
| | - Chan Sonavine Nget
- Institute of Cardiometabolism and Nutrition (ICAN), Sorbonne Université, INSERM, Paris 75012, France
- Centre de Recherche Saint-Antoine (CRSA), Sorbonne Université, INSERM, Paris 75013, France
| | - Eric Savier
- Institute of Cardiometabolism and Nutrition (ICAN), Sorbonne Université, INSERM, Paris 75012, France
- Centre de Recherche Saint-Antoine (CRSA), Sorbonne Université, INSERM, Paris 75013, France
- Department of Hepatobiliary and Liver Transplantation Surgery, Pitié-Salpêtrière Hospital, Assistance Publique-Hôpitaux de Paris, Paris 75013, France
| | - Muhammad Atif
- Centre d'immunologie et maladies infectieuses, Sorbonne Université, INSERM, U1135, Paris 75013, France
| | - Philippe Lesnik
- Institute of Cardiometabolism and Nutrition (ICAN), Sorbonne Université, INSERM, Paris 75012, France
| | - Romain Morichon
- Production et Analyse des données en Sciences de la vie et en Santé (PASS), Sorbonne Université, INSERM, UMS 37, Paris 75013, France
| | - Yves Chrétien
- Institute of Cardiometabolism and Nutrition (ICAN), Sorbonne Université, INSERM, Paris 75012, France
- Centre de Recherche Saint-Antoine (CRSA), Sorbonne Université, INSERM, Paris 75013, France
| | - Yvon Calmus
- Department of Medical Liver Transplantation, Pitié-Salpêtrière Hospital, Assistance Publique-Hôpitaux de Paris, Paris 75013, France
| | - Olivier Scatton
- Institute of Cardiometabolism and Nutrition (ICAN), Sorbonne Université, INSERM, Paris 75012, France
- Centre de Recherche Saint-Antoine (CRSA), Sorbonne Université, INSERM, Paris 75013, France
- Department of Hepatobiliary and Liver Transplantation Surgery, Pitié-Salpêtrière Hospital, Assistance Publique-Hôpitaux de Paris, Paris 75013, France
| | - Chantal Housset
- Institute of Cardiometabolism and Nutrition (ICAN), Sorbonne Université, INSERM, Paris 75012, France
- Centre de Recherche Saint-Antoine (CRSA), Sorbonne Université, INSERM, Paris 75013, France
- Department of Hepatology, Reference Center for Inflammatory Biliary Diseases and Autoimmune Hepatitis, Saint-Antoine Hospital, Assistance Publique-Hôpitaux de Paris, Paris 75012, France
| | - Filomena Conti
- Institute of Cardiometabolism and Nutrition (ICAN), Sorbonne Université, INSERM, Paris 75012, France
- Centre de Recherche Saint-Antoine (CRSA), Sorbonne Université, INSERM, Paris 75013, France
- Department of Medical Liver Transplantation, Pitié-Salpêtrière Hospital, Assistance Publique-Hôpitaux de Paris, Paris 75013, France
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Kostrzewski T, Maraver P, Ouro-Gnao L, Levi A, Snow S, Miedzik A, Rombouts K, Hughes D. A Microphysiological System for Studying Nonalcoholic Steatohepatitis. Hepatol Commun 2019; 4:77-91. [PMID: 31909357 PMCID: PMC6939502 DOI: 10.1002/hep4.1450] [Citation(s) in RCA: 38] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/23/2019] [Accepted: 10/25/2019] [Indexed: 12/14/2022] Open
Abstract
Nonalcoholic steatohepatitis (NASH) is the most severe form of nonalcoholic fatty liver disease (NAFLD), which to date has no approved drug treatments. There is an urgent need for better understanding of the genetic and molecular pathways that underlie NAFLD/NASH, and currently available preclinical models, be they in vivo or in vitro, do not fully represent key aspects of the human disease state. We have developed a human in vitro co‐culture NASH model using primary human hepatocytes, Kupffer cells and hepatic stellate cells, which are cultured together as microtissues in a perfused three‐dimensional microphysiological system (MPS). The microtissues were cultured in medium containing free fatty acids for at least 2 weeks, to induce a NASH‐like phenotype. The co‐culture microtissues within the MPS display a NASH‐like phenotype, showing key features of the disease including hepatic fat accumulation, the production of an inflammatory milieu, and the expression of profibrotic markers. Addition of lipopolysaccharide resulted in a more pro‐inflammatory milieu. In the model, obeticholic acid ameliorated the NASH phenotype. Microtissues were formed from both wild‐type and patatin‐like phospholipase domain containing 3 (PNPLA3) I148M mutant hepatic stellate cells. Stellate cells carrying the mutation enhanced the overall disease state of the model and in particular produced a more pro‐inflammatory milieu. Conclusion: The MPS model displays a phenotype akin to advanced NAFLD or NASH and has utility as a tool for exploring mechanisms underlying the disease. Furthermore, we demonstrate that in co‐culture the PNPLA3 I148M mutation alone can cause hepatic stellate cells to enhance the overall NASH disease phenotype.
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Affiliation(s)
| | - Paloma Maraver
- CN Bio Innovations Ltd. Welwyn Garden City Hertfordshire United Kingdom
| | - Larissa Ouro-Gnao
- CN Bio Innovations Ltd. Welwyn Garden City Hertfordshire United Kingdom
| | - Ana Levi
- Institute for Liver and Digestive Health, Regenerative Medicine and Fibrosis Group, Royal Free University College London United Kingdom
| | - Sophie Snow
- CN Bio Innovations Ltd. Welwyn Garden City Hertfordshire United Kingdom
| | - Alina Miedzik
- CN Bio Innovations Ltd. Welwyn Garden City Hertfordshire United Kingdom
| | - Krista Rombouts
- Institute for Liver and Digestive Health, Regenerative Medicine and Fibrosis Group, Royal Free University College London United Kingdom
| | - David Hughes
- CN Bio Innovations Ltd. Welwyn Garden City Hertfordshire United Kingdom
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9
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Kiamehr M, Heiskanen L, Laufer T, Düsterloh A, Kahraman M, Käkelä R, Laaksonen R, Aalto-Setälä K. Dedifferentiation of Primary Hepatocytes is Accompanied with Reorganization of Lipid Metabolism Indicated by Altered Molecular Lipid and miRNA Profiles. Int J Mol Sci 2019; 20:ijms20122910. [PMID: 31207892 PMCID: PMC6627955 DOI: 10.3390/ijms20122910] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2019] [Revised: 06/10/2019] [Accepted: 06/11/2019] [Indexed: 02/06/2023] Open
Abstract
Aim: Primary human hepatocytes (PHHs) undergo dedifferentiation upon the two-dimensional (2D) culture, which particularly hinders their utility in long-term in vitro studies. Lipids, as a major class of biomolecules, play crucial roles in cellular energy storage, structure, and signaling. Here, for the first time, we mapped the alterations in the lipid profile of the dedifferentiating PHHs and studied the possible role of lipids in the loss of the phenotype of PHHs. Simultaneously, differentially expressed miRNAs associated with changes in the lipids and fatty acids (FAs) of the dedifferentiating PHHs were investigated. Methods: PHHs were cultured in monolayer and their phenotype was monitored morphologically, genetically, and biochemically for five days. The lipid and miRNA profile of the PHHs were analyzed by mass spectrometry and Agilent microarray, respectively. In addition, 24 key genes involved in the metabolism of lipids and FAs were investigated by qPCR. Results: The typical morphology of PHHs was lost from day 3 onward. Additionally, ALB and CYP genes were downregulated in the cultured PHHs. Lipidomics revealed a clear increase in the saturated fatty acids (SFA) and monounsaturated fatty acids (MUFA) containing lipids, but a decrease in the polyunsaturated fatty acids (PUFA) containing lipids during the dedifferentiation of PHHs. In line with this, FASN, SCD, ELOVL1, ELOVL3, and ELOVL7 were upregulated but ELOVL2 was downregulated in the dedifferentiated PHHs. Furthermore, differentially expressed miRNAs were identified, and the constantly upregulated miR-27a and miR-21, and downregulated miR-30 may have regulated the synthesis, accumulation and secretion of PHH lipids during the dedifferentiation. Conclusion: Our results showed major alterations in the molecular lipid species profiles, lipid-metabolizing enzyme expression as wells as miRNA profiles of the PHHs during their prolonged culture, which in concert could play important roles in the PHHs’ loss of phenotype. These findings promote the understanding from the dedifferentiation process and could help in developing optimal culture conditions, which better meet the needs of the PHHs and support their original phenotype.
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Affiliation(s)
- Mostafa Kiamehr
- BioMediTech, Faculty of Medicine and Health Technology, Tampere University, 33520 Tampere, Finland.
| | | | - Thomas Laufer
- Hummingbird Diagnostics GmbH, 69120 Heidelberg, Germany.
- Department of Human Genetics, Saarland University, 66421 Homburg, Germany.
| | | | - Mustafa Kahraman
- Hummingbird Diagnostics GmbH, 69120 Heidelberg, Germany.
- Clinical Bioinformatics, Saarland University, 66123 Saarbrücken, Germany.
| | - Reijo Käkelä
- Helsinki University Lipidomics Unit, Helsinki Institute for Life Science (HiLIFE) and Molecular and Integrative Biosciences Research Programme, University of Helsinki, FI-00014 Helsinki, Finland.
| | - Reijo Laaksonen
- BioMediTech, Faculty of Medicine and Health Technology, Tampere University, 33520 Tampere, Finland.
- Zora Biosciences, 02150 Espoo, Finland.
| | - Katriina Aalto-Setälä
- BioMediTech, Faculty of Medicine and Health Technology, Tampere University, 33520 Tampere, Finland.
- Heart Hospital, Tampere University Hospital, 33520 Tampere, Finland.
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10
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Green CJ, Parry SA, Gunn PJ, Ceresa CDL, Rosqvist F, Piché ME, Hodson L. Studying non-alcoholic fatty liver disease: the ins and outs of in vivo, ex vivo and in vitro human models. Horm Mol Biol Clin Investig 2018; 41:/j/hmbci.ahead-of-print/hmbci-2018-0038/hmbci-2018-0038.xml. [PMID: 30098284 DOI: 10.1515/hmbci-2018-0038] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2018] [Accepted: 06/22/2018] [Indexed: 02/07/2023]
Abstract
The prevalence of non-alcoholic fatty liver disease (NAFLD) is increasing. Determining the pathogenesis and pathophysiology of human NAFLD will allow for evidence-based prevention strategies, and more targeted mechanistic investigations. Various in vivo, ex situ and in vitro models may be utilised to study NAFLD; but all come with their own specific caveats. Here, we review the human-based models and discuss their advantages and limitations in regards to studying the development and progression of NAFLD. Overall, in vivo whole-body human studies are advantageous in that they allow for investigation within the physiological setting, however, limited accessibility to the liver makes direct investigations challenging. Non-invasive imaging techniques are able to somewhat overcome this challenge, whilst the use of stable-isotope tracers enables mechanistic insight to be obtained. Recent technological advances (i.e. normothermic machine perfusion) have opened new opportunities to investigate whole-organ metabolism, thus ex situ livers can be investigated directly. Therefore, investigations that cannot be performed in vivo in humans have the potential to be undertaken. In vitro models offer the ability to perform investigations at a cellular level, aiding in elucidating the molecular mechanisms of NAFLD. However, a number of current models do not closely resemble the human condition and work is ongoing to optimise culturing parameters in order to recapitulate this. In summary, no single model currently provides insight into the development, pathophysiology and progression across the NAFLD spectrum, each experimental model has limitations, which need to be taken into consideration to ensure appropriate conclusions and extrapolation of findings are made.
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Affiliation(s)
- Charlotte J Green
- Oxford Centre for Diabetes, Endocrinology and Metabolism, University of Oxford, Churchill Hospital, Oxford, UK
| | - Siôn A Parry
- Oxford Centre for Diabetes, Endocrinology and Metabolism, University of Oxford, Churchill Hospital, Oxford, UK
| | - Pippa J Gunn
- Oxford Centre for Diabetes, Endocrinology and Metabolism, University of Oxford, Churchill Hospital, Oxford, UK
| | - Carlo D L Ceresa
- Oxford Centre for Diabetes, Endocrinology and Metabolism, University of Oxford, Churchill Hospital, Oxford, UK
- Nuffield Department of Surgical Sciences, University of Oxford, Oxford, UK
| | - Fredrik Rosqvist
- Oxford Centre for Diabetes, Endocrinology and Metabolism, University of Oxford, Churchill Hospital, Oxford, UK
- Department of Public Health and Caring Sciences, Clinical Nutrition and Metabolism, Uppsala University, Uppsala, Sweden
| | - Marie-Eve Piché
- Oxford Centre for Diabetes, Endocrinology and Metabolism, University of Oxford, Churchill Hospital, Oxford, UK
- Quebec Heart and Lung Institute, Laval University, Quebec, Canada
| | - Leanne Hodson
- University of Oxford, Oxford Centre for Diabetes, Endocrinology and Metabolism, Radcliffe Department of Medicine, Churchill Hospital,Old Road Headington, Oxford OX3 7LE, United Kingdom of Great Britain and Northern Ireland
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11
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Chiappini F, Coilly A, Kadar H, Gual P, Tran A, Desterke C, Samuel D, Duclos-Vallée JC, Touboul D, Bertrand-Michel J, Brunelle A, Guettier C, Le Naour F. Metabolism dysregulation induces a specific lipid signature of nonalcoholic steatohepatitis in patients. Sci Rep 2017; 7:46658. [PMID: 28436449 PMCID: PMC5402394 DOI: 10.1038/srep46658] [Citation(s) in RCA: 155] [Impact Index Per Article: 22.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2016] [Accepted: 03/28/2017] [Indexed: 02/07/2023] Open
Abstract
Nonalcoholic steatohepatitis (NASH) is a condition which can progress to cirrhosis and hepatocellular carcinoma. Markers for NASH diagnosis are still lacking. We performed a comprehensive lipidomic analysis on human liver biopsies including normal liver, nonalcoholic fatty liver and NASH. Random forests-based machine learning approach allowed characterizing a signature of 32 lipids discriminating NASH with 100% sensitivity and specificity. Furthermore, we validated this signature in an independent group of NASH patients. Then, metabolism dysregulations were investigated in both patients and murine models. Alterations of elongase and desaturase activities were observed along the fatty acid synthesis pathway. The decreased activity of the desaturase FADS1 appeared as a bottleneck, leading upstream to an accumulation of fatty acids and downstream to a deficiency of long-chain fatty acids resulting to impaired phospholipid synthesis. In NASH, mass spectrometry imaging on tissue section revealed the spreading into the hepatic parenchyma of selectively accumulated fatty acids. Such lipids constituted a highly toxic mixture to human hepatocytes. In conclusion, this study characterized a specific and sensitive lipid signature of NASH and positioned FADS1 as a significant player in accumulating toxic lipids during NASH progression.
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Affiliation(s)
- Franck Chiappini
- Inserm, Unité 1193, Villejuif, F-94800, France.,Univ Paris-Sud, UMR-S1193, Villejuif, F-94800, France.,DHU Hepatinov, Villejuif, F-94800, France
| | - Audrey Coilly
- Inserm, Unité 1193, Villejuif, F-94800, France.,Univ Paris-Sud, UMR-S1193, Villejuif, F-94800, France.,DHU Hepatinov, Villejuif, F-94800, France.,AP-HP, Hôpital Paul-Brousse, Centre Hépato-Biliaire, Villejuif, F-94800, France
| | - Hanane Kadar
- Institut de Chimie des Substances Naturelles, CNRS UPR 2301, Univ. Paris-Sud, Université Paris-Saclay, F-91198 Gif-Sur-Yvette, France
| | - Philippe Gual
- Inserm, Unité 1065, Nice, F-06204, France.,University of Nice-Sophia-Antipolis, Nice, F-06204, France.,Centre Hospitalier Universitaire de Nice, Hôpital L'Archet, Nice Cedex 3, F-06202, France
| | - Albert Tran
- Inserm, Unité 1065, Nice, F-06204, France.,University of Nice-Sophia-Antipolis, Nice, F-06204, France.,Centre Hospitalier Universitaire de Nice, Hôpital L'Archet, Nice Cedex 3, F-06202, France
| | - Christophe Desterke
- Inserm, US33, Villejuif, F-94800, France.,Univ Paris-Sud, US33, Villejuif, F-94800, France
| | - Didier Samuel
- Inserm, Unité 1193, Villejuif, F-94800, France.,Univ Paris-Sud, UMR-S1193, Villejuif, F-94800, France.,DHU Hepatinov, Villejuif, F-94800, France.,AP-HP, Hôpital Paul-Brousse, Centre Hépato-Biliaire, Villejuif, F-94800, France
| | - Jean-Charles Duclos-Vallée
- Inserm, Unité 1193, Villejuif, F-94800, France.,Univ Paris-Sud, UMR-S1193, Villejuif, F-94800, France.,DHU Hepatinov, Villejuif, F-94800, France.,AP-HP, Hôpital Paul-Brousse, Centre Hépato-Biliaire, Villejuif, F-94800, France
| | - David Touboul
- Institut de Chimie des Substances Naturelles, CNRS UPR 2301, Univ. Paris-Sud, Université Paris-Saclay, F-91198 Gif-Sur-Yvette, France
| | | | - Alain Brunelle
- Institut de Chimie des Substances Naturelles, CNRS UPR 2301, Univ. Paris-Sud, Université Paris-Saclay, F-91198 Gif-Sur-Yvette, France
| | - Catherine Guettier
- Inserm, Unité 1193, Villejuif, F-94800, France.,Univ Paris-Sud, UMR-S1193, Villejuif, F-94800, France.,DHU Hepatinov, Villejuif, F-94800, France.,AP-HP, Hôpital du Kremlin-Bicêtre, Service d'Anatomopathologie, Le Kremlin-Bicêtre, F-94275, France
| | - François Le Naour
- Inserm, Unité 1193, Villejuif, F-94800, France.,Univ Paris-Sud, UMR-S1193, Villejuif, F-94800, France.,DHU Hepatinov, Villejuif, F-94800, France.,Inserm, US33, Villejuif, F-94800, France.,Univ Paris-Sud, US33, Villejuif, F-94800, France
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12
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Pramfalk C, Larsson L, Härdfeldt J, Eriksson M, Parini P. Culturing of HepG2 cells with human serum improve their functionality and suitability in studies of lipid metabolism. Biochim Biophys Acta Mol Cell Biol Lipids 2016; 1861:51-59. [DOI: 10.1016/j.bbalip.2015.10.008] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2015] [Revised: 10/05/2015] [Accepted: 10/23/2015] [Indexed: 11/17/2022]
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13
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Sid V, Wu N, Sarna LK, Siow YL, House JD, O K. Folic acid supplementation during high-fat diet feeding restores AMPK activation via an AMP-LKB1-dependent mechanism. Am J Physiol Regul Integr Comp Physiol 2015; 309:R1215-25. [PMID: 26400185 DOI: 10.1152/ajpregu.00260.2015] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2015] [Accepted: 09/16/2015] [Indexed: 12/11/2022]
Abstract
AMPK is an endogenous energy sensor that regulates lipid and carbohydrate metabolism. Nonalcoholic fatty liver disease (NAFLD) is regarded as a hepatic manifestation of metabolic syndrome with impaired lipid and glucose metabolism and increased oxidative stress. Our recent study showed that folic acid supplementation attenuated hepatic oxidative stress and lipid accumulation in high-fat diet-fed mice. The aim of the present study was to investigate the effect of folic acid on hepatic AMPK during high-fat diet feeding and the mechanisms involved. Male C57BL/6J mice were fed a control diet (10% kcal fat), a high-fat diet (60% kcal fat), or a high-fat diet supplemented with folic acid (26 mg/kg diet) for 5 wk. Mice fed a high-fat diet exhibited hyperglycemia, hepatic cholesterol accumulation, and reduced hepatic AMPK phosphorylation. Folic acid supplementation restored AMPK phosphorylation (activation) and reduced blood glucose and hepatic cholesterol levels. Activation of AMPK by folic acid was mediated through an elevation of its allosteric activator AMP and activation of its upstream kinase, namely, liver kinase B1 (LKB1) in the liver. Consistent with in vivo findings, 5-methyltetrahydrofolate (bioactive form of folate) restored phosphorylation (activation) of both AMPK and LKB1 in palmitic acid-treated HepG2 cells. Activation of AMPK by folic acid might be responsible for AMPK-dependent phosphorylation of HMG-CoA reductase, leading to reduced hepatic cholesterol synthesis during high-fat diet feeding. These results suggest that folic acid supplementation may improve cholesterol and glucose metabolism by restoration of AMPK activation in the liver.
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Affiliation(s)
- Victoria Sid
- St. Boniface Hospital Research Centre, Winnipeg, Manitoba, Canada; Department of Physiology and Pathophysiology, Winnipeg, Manitoba, Canada
| | - Nan Wu
- St. Boniface Hospital Research Centre, Winnipeg, Manitoba, Canada; Department of Physiology and Pathophysiology, Winnipeg, Manitoba, Canada
| | - Lindsei K Sarna
- St. Boniface Hospital Research Centre, Winnipeg, Manitoba, Canada; Department of Animal Science, University of Manitoba, Winnipeg, Manitoba, Canada
| | - Yaw L Siow
- St. Boniface Hospital Research Centre, Winnipeg, Manitoba, Canada; Department of Physiology and Pathophysiology, Winnipeg, Manitoba, Canada; Agriculture and Agri-Food Canada, Winnipeg, Manitoba, Canada; and
| | - James D House
- Department of Animal Science, University of Manitoba, Winnipeg, Manitoba, Canada; Department of Human Nutritional Science, University of Manitoba, Winnipeg, Manitoba, Canada
| | - Karmin O
- St. Boniface Hospital Research Centre, Winnipeg, Manitoba, Canada; Department of Physiology and Pathophysiology, Winnipeg, Manitoba, Canada; Department of Animal Science, University of Manitoba, Winnipeg, Manitoba, Canada;
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14
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Inhibition of miR-29 has a significant lipid-lowering benefit through suppression of lipogenic programs in liver. Sci Rep 2015; 5:12911. [PMID: 26246194 PMCID: PMC4526858 DOI: 10.1038/srep12911] [Citation(s) in RCA: 59] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2015] [Accepted: 07/09/2015] [Indexed: 12/19/2022] Open
Abstract
MicroRNAs (miRNAs) are important regulators and potential therapeutic targets of metabolic disease. In this study we show by in vivo administration of locked nucleic acid (LNA) inhibitors that suppression of endogenous miR-29 lowers plasma cholesterol levels by ~40%, commensurate with the effect of statins, and reduces fatty acid content in the liver by ~20%. Whole transcriptome sequencing of the liver reveals 883 genes dysregulated (612 down, 271 up) by inhibition of miR-29. The set of 612 down-regulated genes are most significantly over-represented in lipid synthesis pathways. Among the up-regulated genes are the anti-lipogenic deacetylase sirtuin 1 (Sirt1) and the anti-lipogenic transcription factor aryl hydrocarbon receptor (Ahr), the latter of which we demonstrate is a direct target of miR-29. In vitro radiolabeled acetate incorporation assays confirm that pharmacologic inhibition of miR-29 significantly reduces de novo cholesterol and fatty acid synthesis. Our findings indicate that miR-29 controls hepatic lipogenic programs, likely in part through regulation of Ahr and Sirt1, and therefore may represent a candidate therapeutic target for metabolic disorders such as dyslipidemia.
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15
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Green CJ, Pramfalk C, Morten KJ, Hodson L. From whole body to cellular models of hepatic triglyceride metabolism: man has got to know his limitations. Am J Physiol Endocrinol Metab 2015; 308:E1-20. [PMID: 25352434 PMCID: PMC4281685 DOI: 10.1152/ajpendo.00192.2014] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
The liver is a main metabolic organ in the human body and carries out a vital role in lipid metabolism. Nonalcoholic fatty liver disease (NAFLD) is one of the most common liver diseases, encompassing a spectrum of conditions from simple fatty liver (hepatic steatosis) through to cirrhosis. Although obesity is a known risk factor for hepatic steatosis, it remains unclear what factor(s) is/are responsible for the primary event leading to retention of intrahepatocellular fat. Studying hepatic processes and the etiology and progression of disease in vivo in humans is challenging, not least as NAFLD may take years to develop. We present here a review of experimental models and approaches that have been used to assess liver triglyceride metabolism and discuss their usefulness in helping to understand the aetiology and development of NAFLD.
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Affiliation(s)
- Charlotte J Green
- Oxford Centre for Diabetes, Endocrinology and Metabolism, University of Oxford, Churchill Hospital, Oxford United Kingdom; and
| | - Camilla Pramfalk
- Oxford Centre for Diabetes, Endocrinology and Metabolism, University of Oxford, Churchill Hospital, Oxford United Kingdom; and
| | - Karl J Morten
- Nuffield Department of Obstetrics and Gynaecology, University of Oxford, John Radcliffe Hospital, Oxford, United Kingdom
| | - Leanne Hodson
- Oxford Centre for Diabetes, Endocrinology and Metabolism, University of Oxford, Churchill Hospital, Oxford United Kingdom; and
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16
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Steenbergen RHG, Joyce MA, Thomas BS, Jones D, Law J, Russell R, Houghton M, Tyrrell DL. Human serum leads to differentiation of human hepatoma cells, restoration of very-low-density lipoprotein secretion, and a 1000-fold increase in HCV Japanese fulminant hepatitis type 1 titers. Hepatology 2013; 58:1907-17. [PMID: 23775894 DOI: 10.1002/hep.26566] [Citation(s) in RCA: 52] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/30/2013] [Accepted: 05/27/2013] [Indexed: 12/23/2022]
Abstract
UNLABELLED In this study, we differentiated the human hepatoma cell line Huh7.5 by supplementing tissue culture media with human serum (HS) and examined the production of hepatitis C virus (HCV) by these cells. We compared the standard tissue culture protocol, using media supplemented with 10% fetal bovine serum (FBS), to media supplemented with 2% HS. Cells cultured in HS undergo rapid growth arrest, have a hepatocyte-like morphology, and increase the expression of hepatocyte differentiation markers. In addition, expression of cell adhesion proteins claudin-1, occludin, and e-cadherin are also increased. The lipid droplet content of these cells is highly increased, as are key lipid metabolism regulators liver X receptor alpha, peroxisome proliferator-activated receptor (PPAR)-α, and PPAR-γ. Very-low-density lipoprotein secretion, which is absent in FBS-grown cells, is restored in Huh7.5 cells that are cultured in HS. All these factors have been implicated in the life cycle of HCV. We show that viral production of Japanese fulminant hepatitis type 1 increases 1,000-fold when cells are grown in HS, compared to standard FBS culture conditions. The virus produced under these conditions is associated with apolipoprotein B, has a lower density, higher specific infectivity, and has a longer half-life than virus produced in media supplemented with FBS. CONCLUSION We describe a convenient, cost-effective method to produce hepatocyte-like cells, which produce large amounts of virus that more closely resemble HCV present in serum of infected patients.
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Affiliation(s)
- Rineke H G Steenbergen
- Department ofMedical Microbiology and Immunology, University of Alberta, Edmonton, Alberta, Canada; Li Ka Shing Institute of Virology, University of Alberta, Edmonton, Alberta, Canada
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17
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Vickers KC, Sethupathy P, Baran-Gale J, Remaley AT. Complexity of microRNA function and the role of isomiRs in lipid homeostasis. J Lipid Res 2013; 54:1182-91. [PMID: 23505317 DOI: 10.1194/jlr.r034801] [Citation(s) in RCA: 40] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
MicroRNAs (miRNAs) are key posttranscriptional regulators of biological pathways that govern lipid metabolic phenotypes. Recent advances in high-throughput small RNA sequencing technology have revealed the complex and dynamic repertoire of miRNAs. Specifically, it has been demonstrated that a single genomic locus can give rise to multiple, functionally distinct miRNA isoforms (isomiR). There are several mechanisms by which isomiRs can be generated, including processing heterogeneity and posttranscriptional modifications, such as RNA editing, exonuclease-mediated nucleotide trimming, and/or nontemplated nucleotide addition (NTA). NTAs are dominant at the 3'-end of a miRNA, are most commonly uridylation or adenlyation events, and are catalyzed by one or more of several nucleotidyl transferase enzymes. 3' NTAs can affect miRNA stability and/or activity and are physiologically regulated, whereas modifications to the 5'-ends of miRNAs likely alter miRNA targeting activity. Recent evidence also suggests that the biogenesis of specific miRNAs, or small RNAs that act as miRNAs, can occur through unconventional mechanisms that circumvent key canonical miRNA processing steps. The unveiling of miRNA diversity has significantly added to our view of the complexity of miRNA function. In this review we present the current understanding of the biological relevance of isomiRs and their potential role in regulating lipid metabolism.
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Affiliation(s)
- Kasey C Vickers
- Department of Medicine, Vanderbilt University School of Medicine, Nashville, TN, USA.
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