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Wild SL, Elghajiji A, Grimaldos Rodriguez C, Weston SD, Burke ZD, Tosh D. The Canonical Wnt Pathway as a Key Regulator in Liver Development, Differentiation and Homeostatic Renewal. Genes (Basel) 2020; 11:genes11101163. [PMID: 33008122 PMCID: PMC7599793 DOI: 10.3390/genes11101163] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2020] [Revised: 09/21/2020] [Accepted: 09/29/2020] [Indexed: 02/06/2023] Open
Abstract
The canonical Wnt (Wnt/β-catenin) signalling pathway is highly conserved and plays a critical role in regulating cellular processes both during development and in adult tissue homeostasis. The Wnt/β-catenin signalling pathway is vital for correct body patterning and is involved in fate specification of the gut tube, the primitive precursor of liver. In adults, the Wnt/β-catenin pathway is increasingly recognised as an important regulator of metabolic zonation, homeostatic renewal and regeneration in response to injury throughout the liver. Herein, we review recent developments relating to the key role of the pathway in the patterning and fate specification of the liver, in the directed differentiation of pluripotent stem cells into hepatocytes and in governing proliferation and zonation in the adult liver. We pay particular attention to recent contributions to the controversy surrounding homeostatic renewal and proliferation in response to injury. Furthermore, we discuss how crosstalk between the Wnt/β-catenin and Hedgehog (Hh) and hypoxia inducible factor (HIF) pathways works to maintain liver homeostasis. Advancing our understanding of this pathway will benefit our ability to model disease, screen drugs and generate tissue and organ replacements for regenerative medicine.
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Hadi R, Shin K, Reder N, Alpert L, Koch L, Choi WT, Swanson PE, Hart J, Westerhoff M. Utility of glutamine synthetase immunohistochemistry in identifying features of regressed cirrhosis. Mod Pathol 2020; 33:448-455. [PMID: 31391527 DOI: 10.1038/s41379-019-0346-1] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2019] [Accepted: 07/13/2019] [Indexed: 02/07/2023]
Abstract
The prevailing view that cirrhosis is irreversible has been challenged. It has been proposed that varying degrees of fibrosis regression can be achieved if the injurious agent is removed. In the normal liver, glutamine synthetase immunostaining is present around central veins. In regressed cirrhosis, although fibrous bands between portal tracts and central veins may largely be resorbed, the abnormal portal tract-central vein adherence often remains. Hence, we hypothesized that aberrant glutamine synthetase positivity adjacent to portal tracts would help identify regressed cirrhosis. We performed glutamine synthetase immunohistochemistry on 49 liver specimens (16 regressed cirrhosis, 18 cirrhotic, and 15 normal livers). Qualification for regressed cirrhosis required the following histologic features: curved, delicate incomplete septa, portal tract-central vein adhesions, and portal tract "remnants" (portal tracts with no venous branch). Out of 16, 14 regressed cirrhosis cases had baseline cirrhosis established based on previous biopsy or signs of cirrhosis based on physical exam, laboratory, and radiological findings. All regressed cirrhosis cases (100%) had areas of aberrant glutamine synthetase positivity adjacent to portal tracts, indicating that portal tract-central vein approximation had occurred (p < 0.001 compared to all other categories). No normal cases had glutamine synthetase positivity adjacent to portal tracts, and half of cirrhosis cases had areas showing features of regression, with focal glutamine synthetase positivity adjacent to portal tracts. Overall, glutamine synthetase expression showed highly significant differences among the three categories (p < 0.001). This study shows that aberrant glutamine synthetase positivity adjacent to portal tracts is present in regressed cirrhosis and can be useful in identifying regressed cirrhosis when it is histologically suspected.
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Affiliation(s)
- Rouba Hadi
- Department of Anatomic Pathology, University of Washington Medical Center, 1959 NE Pacific St, NE 110, Seattle, WA, 98195, USA.
| | - Kseniya Shin
- Department of Anatomic Pathology, University of Washington Medical Center, 1959 NE Pacific St, NE 110, Seattle, WA, 98195, USA
| | - Nicholas Reder
- Department of Anatomic Pathology, University of Washington Medical Center, 1959 NE Pacific St, NE 110, Seattle, WA, 98195, USA
| | - Lindsay Alpert
- Department of Anatomic Pathology, University of Chicago, A27 S Maryland Ave, Chicago, IL, 60637, USA
| | - Lisa Koch
- Department of Anatomic Pathology, University of Washington Medical Center, 1959 NE Pacific St, NE 110, Seattle, WA, 98195, USA
| | - Won-Tak Choi
- Department of Anatomic Pathology, University of California San Francisco, 505 Parnassus Avenue, Room M-552, San Francisco, CA, 94143, USA
| | - Paul E Swanson
- Department of Anatomic Pathology, University of Washington Medical Center, 1959 NE Pacific St, NE 110, Seattle, WA, 98195, USA
| | - John Hart
- Department of Anatomic Pathology, University of Chicago, A27 S Maryland Ave, Chicago, IL, 60637, USA
| | - Maria Westerhoff
- Department of Anatomic Pathology, University of Michigan Health System, NCRC building 35 2800 Plymouth Road, Ann Arbor, MI, 48109, USA
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3
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Mak KM, Png CYM. The Hepatic Central Vein: Structure, Fibrosis, and Role in Liver Biology. Anat Rec (Hoboken) 2019; 303:1747-1767. [PMID: 31581357 DOI: 10.1002/ar.24273] [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] [Received: 05/04/2019] [Revised: 08/11/2019] [Accepted: 08/14/2019] [Indexed: 12/19/2022]
Abstract
The hepatic central vein is a primary source of Wnt2, Wnt9b, and R-spondin3. These angiocrines activate ß-catenin signaling to regulate hepatic metabolic zonation and perivenous gene expression in mice. Little is known about the central vein ultrastructure. Here, we describe the morphological-functional correlates of the central vein and its draining and branching patterns. Central vein fibrosis occurs in liver disease and is often accompanied by perivenous perisinusoidal fibrosis, which may affect perivenous gene expression. We review the biological properties of perivenous hepatocytes and glutamine synthetase that serve as a biomarker of perivenous hepatocytes. Glutamine synthetase and P4502E1 are indicators of ß-catenin activity in centrilobular liver injury and regeneration. The Wnt/ß-catenin pathway is the master regulator of hepatic metabolic zonation and perivenous gene expression and is modulated by the R-spondin-LGR4/5-ZNRF3/RNF43 module. We examined the structures of the molecules of these pathways and their involvements in liver biology. Central vein-derived Wnts and R-spondin3 participate in the cellular-molecular circuitry of the Wnt/ß-catenin and R-spondin-LGR4/5-ZNRF3/RNF43 module. The transport and secretion of lipidated Wnts in Wnt-producing cells require Wntless protein. Secreted Wnts are carried on exosomes in the extracellular matrix to responder cells. The modes of release of Wnts and R-spondin3 from central veins and their transit in the venular wall toward perivenous hepatocytes are unknown. We hypothesize that central vein fibrosis may impact perivenous gene expression. The proposal that the central vein constitutes an anatomical niche of perivenous stem cells that subserve homeostatic hepatic renewal still needs studies using additional mouse models for validation. Anat Rec, 2019. © 2019 American Association for Anatomy Anat Rec, 303:1747-1767, 2020. © 2019 American Association for Anatomy.
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Affiliation(s)
- Ki M Mak
- Department of Medical Education and Center for Anatomy and Functional Morphology, Icahn School of Medicine at Mount Sinai, New York, New York
| | - C Y Maximilian Png
- Division of Vascular Surgery, Massachusetts General Hospital, Boston, Massachusetts
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Blau BJ, Miki T. The role of cellular interactions in the induction of hepatocyte polarity and functional maturation in stem cell-derived hepatic cells. Differentiation 2019; 106:42-48. [PMID: 30878880 DOI: 10.1016/j.diff.2019.02.006] [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] [Received: 01/25/2019] [Revised: 02/25/2019] [Accepted: 02/28/2019] [Indexed: 02/08/2023]
Abstract
The unique microenvironment found within the liver in vivo plays a key role in the induction of functional maturation in the developing hepatocyte. During organogenesis, hepatocytes acquire a polar phenotype that allows them to perform their functions of bile production and transport, protein synthesis, metabolism, and detoxification simultaneously, independently, and efficiently. It is thought that the induction of polarity and functional maturation in hepatocytes is dependent on the complex interplay of cell-cell and cell-extracellular matrix (ECM) interactions. While this process is highly efficient in the human liver, it has been shown that hepatocytes rapidly lose their functions when placed in cell culture. This poses a challenge for the development of a bioartificial liver (BAL) support system, which utilizes a live cellular source to perform hepatic functions in the event of acute liver failure or primary nonfunction. However, once the molecular mechanisms underlying the induction of hepatocyte polarity are fully identified, it will be possible to develop highly functional hepatic cells from human pluripotent stem cells (hPSCs). This new cell line would be an ideal cellular source for a BAL system, as it would have both the functionality and longevity to support a patient through the entire clinical course of treatment. In this review, we explore the literature that has examined the potential mechanisms that induce polarity in the developing hepatocyte and discuss the future implications of this knowledge in a clinical setting from a bioengineering perspective.
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Affiliation(s)
- Brandon J Blau
- Department of Surgery, Keck School of Medicine, University of Southern California, USA
| | - Toshio Miki
- Department of Surgery, Keck School of Medicine, University of Southern California, USA.
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Cochary EF, Kikinis Z, Paulson KE. Positional and temporal regulation of lipogenic gene expression in mouse liver. Gene Expr 2018; 3:265-78. [PMID: 8019127 PMCID: PMC6081618] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
We have examined the dynamics of positional gene expression in mouse liver using the carbohydrate induction of lipogenic genes as a model. Using a protocol of fasting and refeeding a high-carbohydrate, no-fat diet to obtain maximal induction, we investigated the temporal expression and localization of malic enzyme (ME) and fatty acid synthase (FAS). In situ hybridization showed that both ME and FAS were expressed at low basal levels in all hepatocytes in livers of mice fed a control diet. Furthermore, dietary induction of ME and FAS mRNA occurred in periportal cells within 6 hours. After 12 hours, the portal cells were maximal; and after 24-36 hours, all cells showed high levels of message. This was coincident with expression of ME and FAS mRNAs, which appeared to be maximal between 24 and 36 hours. Both steady-state mRNA levels and pericentral localization then declined, until only periportal hepatocytes showed strong expression of ME and FAS. Nuclear transcription rates measured by run-on assay demonstrated that maximal transcription rates preceded maximum mRNA levels by peaking at 12 hours. Furthermore, run-on assays showed that the periportal induction by carbohydrates is primarily a transcriptional response for FAS, and both transcriptional and posttranscriptional for ME. These results indicate that lipogenic gene expression is a temporal response induced by carbohydrate feeding and is regulated by both positional and transcriptional mechanisms.
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Affiliation(s)
- E F Cochary
- Genetics Laboratory, USDA Human Nutrition Research Center on Aging, Tufts University, Boston, MA 02111
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6
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Alison MR. The many ways to mend your liver: A critical appraisal. Int J Exp Pathol 2018; 99:106-112. [PMID: 29882223 DOI: 10.1111/iep.12272] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2018] [Accepted: 05/07/2018] [Indexed: 12/12/2022] Open
Abstract
In the latter half of the 20th century, our understanding of mammalian liver regeneration was shaped by the manner of compensatory hyperplasia occurring after a partial rat liver resection. This response involves almost all hepatocytes and thus is unlikely to be the outcome of the multiple cycling of a small stem cell population. It was most intense in the outer third of lobule, the location closest to the afferent arterial blood supply. With the advent of heritable genetic labelling techniques, usually applied to mice, hitherto unrecognized hepatocytes with clonogenic potential have been discovered, contributing to homoeostatic renewal and/or regenerative responses after tissue loss. This review combines observations from cell lineage tracing studies with other data to summarize the Four proposed anatomical locations for hepatocyte stem cells: the periportal zone, the pericentral zone, a randomized distribution and finally within the intrahepatic biliary tree. As in other endodermal-derived tissues, it appears that there are both homoeostatic stem cells and regenerative stem cells, while some normally homoeostatic stem cells can become more active to boost regeneration.
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Affiliation(s)
- Malcolm R Alison
- Centre for Tumour Biology, Barts Cancer Institute, Barts and The London School of Medicine and Dentistry, London, UK
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Abstract
Under normal homeostatic conditions, hepatocyte renewal is a slow process and complete turnover likely takes at least a year. Studies of hepatocyte regeneration after a two-thirds partial hepatectomy (2/3 PH) have strongly suggested that periportal hepatocytes are the driving force behind regenerative re-population, but recent murine studies have brought greater complexity to the issue. Although periportal hepatocytes are still considered pre-eminent in the response to 2/3 PH, new studies suggest that normal homeostatic renewal is driven by pericentral hepatocytes under the control of Wnts, while pericentral injury provokes the clonal expansion of a subpopulation of periportal hepatocytes expressing low levels of biliary duct genes such as
Sox9 and
osteopontin. Furthermore, some clarity has been given to the debate on the ability of biliary-derived hepatic progenitor cells to generate physiologically meaningful numbers of hepatocytes in injury models, demonstrating that under appropriate circumstances these cells can re-populate the whole liver.
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Affiliation(s)
- Malcolm R Alison
- Centre for Tumour Biology, Barts and The London School of Medicine and Dentistry, London, UK
| | - Wey-Ran Lin
- Department of Gastroenterology and Hepatology, Linkou Chang Gung Memorial Hospital, Taoyuan 333, Taiwan; Department of Medicine, Chang Gung University, Taoyuan 333, Taiwan
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Schleicher J, Tokarski C, Marbach E, Matz-Soja M, Zellmer S, Gebhardt R, Schuster S. Zonation of hepatic fatty acid metabolism - The diversity of its regulation and the benefit of modeling. Biochim Biophys Acta Mol Cell Biol Lipids 2015; 1851:641-56. [PMID: 25677822 DOI: 10.1016/j.bbalip.2015.02.004] [Citation(s) in RCA: 45] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2014] [Revised: 01/26/2015] [Accepted: 02/03/2015] [Indexed: 02/07/2023]
Abstract
A pronounced heterogeneity between hepatocytes in subcellular structure and enzyme activities was discovered more than 50years ago and initiated the idea of metabolic zonation. In the last decades zonation patterns of liver metabolism were extensively investigated for carbohydrate, nitrogen and lipid metabolism. The present review focuses on zonation patterns of the latter. We review recent findings regarding the zonation of fatty acid uptake and oxidation, ketogenesis, triglyceride synthesis and secretion, de novo lipogenesis, as well as bile acid and cholesterol metabolism. In doing so, we expose knowledge gaps and discuss contradictory experimental results, for example on the zonation pattern of fatty acid oxidation and de novo lipogenesis. Thus, possible rewarding directions of further research are identified. Furthermore, recent findings about the regulation of metabolic zonation are summarized, especially regarding the role of hormones, nerve innervation, morphogens, gender differences and the influence of the circadian clock. In the last part of the review, a short collection of models considering hepatic lipid metabolism is provided. We conclude that modeling, despite its proven benefit for understanding of hepatic carbohydrate and ammonia metabolisms, has so far been largely disregarded in the study of lipid metabolism; therefore some possible fields of modeling interest are presented.
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Affiliation(s)
- J Schleicher
- Department of Bioinformatics, University of Jena, Jena, Germany.
| | - C Tokarski
- Department of Bioinformatics, University of Jena, Jena, Germany
| | - E Marbach
- Institute of Biochemistry, Faculty of Medicine, University of Leipzig, Leipzig, Germany
| | - M Matz-Soja
- Institute of Biochemistry, Faculty of Medicine, University of Leipzig, Leipzig, Germany
| | - S Zellmer
- Department of Chemicals and Product Safety, German Federal Institute for Risk Assessment (BfR), Berlin, Germany
| | - R Gebhardt
- Institute of Biochemistry, Faculty of Medicine, University of Leipzig, Leipzig, Germany
| | - S Schuster
- Department of Bioinformatics, University of Jena, Jena, Germany
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9
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Godoy P, Hewitt NJ, Albrecht U, Andersen ME, Ansari N, Bhattacharya S, Bode JG, Bolleyn J, Borner C, Böttger J, Braeuning A, Budinsky RA, Burkhardt B, Cameron NR, Camussi G, Cho CS, Choi YJ, Craig Rowlands J, Dahmen U, Damm G, Dirsch O, Donato MT, Dong J, Dooley S, Drasdo D, Eakins R, Ferreira KS, Fonsato V, Fraczek J, Gebhardt R, Gibson A, Glanemann M, Goldring CEP, Gómez-Lechón MJ, Groothuis GMM, Gustavsson L, Guyot C, Hallifax D, Hammad S, Hayward A, Häussinger D, Hellerbrand C, Hewitt P, Hoehme S, Holzhütter HG, Houston JB, Hrach J, Ito K, Jaeschke H, Keitel V, Kelm JM, Kevin Park B, Kordes C, Kullak-Ublick GA, LeCluyse EL, Lu P, Luebke-Wheeler J, Lutz A, Maltman DJ, Matz-Soja M, McMullen P, Merfort I, Messner S, Meyer C, Mwinyi J, Naisbitt DJ, Nussler AK, Olinga P, Pampaloni F, Pi J, Pluta L, Przyborski SA, Ramachandran A, Rogiers V, Rowe C, Schelcher C, Schmich K, Schwarz M, Singh B, Stelzer EHK, Stieger B, Stöber R, Sugiyama Y, Tetta C, Thasler WE, Vanhaecke T, Vinken M, Weiss TS, Widera A, Woods CG, Xu JJ, Yarborough KM, Hengstler JG. Recent advances in 2D and 3D in vitro systems using primary hepatocytes, alternative hepatocyte sources and non-parenchymal liver cells and their use in investigating mechanisms of hepatotoxicity, cell signaling and ADME. Arch Toxicol 2013; 87:1315-530. [PMID: 23974980 PMCID: PMC3753504 DOI: 10.1007/s00204-013-1078-5] [Citation(s) in RCA: 1062] [Impact Index Per Article: 96.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2013] [Accepted: 05/06/2013] [Indexed: 12/15/2022]
Abstract
This review encompasses the most important advances in liver functions and hepatotoxicity and analyzes which mechanisms can be studied in vitro. In a complex architecture of nested, zonated lobules, the liver consists of approximately 80 % hepatocytes and 20 % non-parenchymal cells, the latter being involved in a secondary phase that may dramatically aggravate the initial damage. Hepatotoxicity, as well as hepatic metabolism, is controlled by a set of nuclear receptors (including PXR, CAR, HNF-4α, FXR, LXR, SHP, VDR and PPAR) and signaling pathways. When isolating liver cells, some pathways are activated, e.g., the RAS/MEK/ERK pathway, whereas others are silenced (e.g. HNF-4α), resulting in up- and downregulation of hundreds of genes. An understanding of these changes is crucial for a correct interpretation of in vitro data. The possibilities and limitations of the most useful liver in vitro systems are summarized, including three-dimensional culture techniques, co-cultures with non-parenchymal cells, hepatospheres, precision cut liver slices and the isolated perfused liver. Also discussed is how closely hepatoma, stem cell and iPS cell-derived hepatocyte-like-cells resemble real hepatocytes. Finally, a summary is given of the state of the art of liver in vitro and mathematical modeling systems that are currently used in the pharmaceutical industry with an emphasis on drug metabolism, prediction of clearance, drug interaction, transporter studies and hepatotoxicity. One key message is that despite our enthusiasm for in vitro systems, we must never lose sight of the in vivo situation. Although hepatocytes have been isolated for decades, the hunt for relevant alternative systems has only just begun.
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Affiliation(s)
- Patricio Godoy
- Leibniz Research Centre for Working Environment and Human Factors (IFADO), 44139 Dortmund, Germany
| | | | - Ute Albrecht
- Clinic for Gastroenterology, Hepatology and Infectious Diseases, Heinrich-Heine-University, Moorenstrasse 5, 40225 Düsseldorf, Germany
| | - Melvin E. Andersen
- The Hamner Institutes for Health Sciences, Research Triangle Park, NC USA
| | - Nariman Ansari
- Buchmann Institute for Molecular Life Sciences (BMLS), Goethe University Frankfurt, Max-von-Laue-Str. 15, 60438 Frankfurt am Main, Germany
| | - Sudin Bhattacharya
- The Hamner Institutes for Health Sciences, Research Triangle Park, NC USA
| | - Johannes Georg Bode
- Clinic for Gastroenterology, Hepatology and Infectious Diseases, Heinrich-Heine-University, Moorenstrasse 5, 40225 Düsseldorf, Germany
| | - Jennifer Bolleyn
- Department of Toxicology, Centre for Pharmaceutical Research, Faculty of Medicine and Pharmacy, Vrije Universiteit Brussel, 1090 Brussels, Belgium
| | - Christoph Borner
- Institute of Molecular Medicine and Cell Research, University of Freiburg, Freiburg, Germany
| | - Jan Böttger
- Institute of Biochemistry, Faculty of Medicine, University of Leipzig, 04103 Leipzig, Germany
| | - Albert Braeuning
- Department of Toxicology, Institute of Experimental and Clinical Pharmacology and Toxicology, Wilhelmstr. 56, 72074 Tübingen, Germany
| | - Robert A. Budinsky
- Toxicology and Environmental Research and Consulting, The Dow Chemical Company, Midland, MI USA
| | - Britta Burkhardt
- BG Trauma Center, Siegfried Weller Institut, Eberhard Karls University Tübingen, 72076 Tübingen, Germany
| | - Neil R. Cameron
- Department of Chemistry, Durham University, Durham, DH1 3LE UK
| | - Giovanni Camussi
- Department of Medical Sciences, University of Torino, 10126 Turin, Italy
| | - Chong-Su Cho
- Department of Agricultural Biotechnology and Research Institute for Agriculture and Life Sciences, Seoul National University, Seoul, 151-921 Korea
| | - Yun-Jaie Choi
- Department of Agricultural Biotechnology and Research Institute for Agriculture and Life Sciences, Seoul National University, Seoul, 151-921 Korea
| | - J. Craig Rowlands
- Toxicology and Environmental Research and Consulting, The Dow Chemical Company, Midland, MI USA
| | - Uta Dahmen
- Experimental Transplantation Surgery, Department of General Visceral, and Vascular Surgery, Friedrich-Schiller-University Jena, 07745 Jena, Germany
| | - Georg Damm
- Department of General-, Visceral- and Transplantation Surgery, Charité University Medicine Berlin, 13353 Berlin, Germany
| | - Olaf Dirsch
- Institute of Pathology, Friedrich-Schiller-University Jena, 07745 Jena, Germany
| | - María Teresa Donato
- Unidad de Hepatología Experimental, IIS Hospital La Fe Avda Campanar 21, 46009 Valencia, Spain
- CIBERehd, Fondo de Investigaciones Sanitarias, Barcelona, Spain
- Departamento de Bioquímica y Biología Molecular, Facultad de Medicina, Universidad de Valencia, Valencia, Spain
| | - Jian Dong
- The Hamner Institutes for Health Sciences, Research Triangle Park, NC USA
| | - Steven Dooley
- Department of Medicine II, Section Molecular Hepatology, Medical Faculty Mannheim, Heidelberg University, Mannheim, Germany
| | - Dirk Drasdo
- Interdisciplinary Center for Bioinformatics (IZBI), University of Leipzig, 04107 Leipzig, Germany
- INRIA (French National Institute for Research in Computer Science and Control), Domaine de Voluceau-Rocquencourt, B.P. 105, 78153 Le Chesnay Cedex, France
- UPMC University of Paris 06, CNRS UMR 7598, Laboratoire Jacques-Louis Lions, 4, pl. Jussieu, 75252 Paris cedex 05, France
| | - Rowena Eakins
- Department of Molecular and Clinical Pharmacology, Centre for Drug Safety Science, Institute of Translational Medicine, University of Liverpool, Liverpool, UK
| | - Karine Sá Ferreira
- Institute of Molecular Medicine and Cell Research, University of Freiburg, Freiburg, Germany
- GRK 1104 From Cells to Organs, Molecular Mechanisms of Organogenesis, Faculty of Biology, University of Freiburg, Freiburg, Germany
| | - Valentina Fonsato
- Department of Medical Sciences, University of Torino, 10126 Turin, Italy
| | - Joanna Fraczek
- Department of Toxicology, Centre for Pharmaceutical Research, Faculty of Medicine and Pharmacy, Vrije Universiteit Brussel, 1090 Brussels, Belgium
| | - Rolf Gebhardt
- Institute of Biochemistry, Faculty of Medicine, University of Leipzig, 04103 Leipzig, Germany
| | - Andrew Gibson
- Department of Molecular and Clinical Pharmacology, Centre for Drug Safety Science, Institute of Translational Medicine, University of Liverpool, Liverpool, UK
| | - Matthias Glanemann
- Department of General-, Visceral- and Transplantation Surgery, Charité University Medicine Berlin, 13353 Berlin, Germany
| | - Chris E. P. Goldring
- Department of Molecular and Clinical Pharmacology, Centre for Drug Safety Science, Institute of Translational Medicine, University of Liverpool, Liverpool, UK
| | - María José Gómez-Lechón
- Unidad de Hepatología Experimental, IIS Hospital La Fe Avda Campanar 21, 46009 Valencia, Spain
- CIBERehd, Fondo de Investigaciones Sanitarias, Barcelona, Spain
| | - Geny M. M. Groothuis
- Department of Pharmacy, Pharmacokinetics Toxicology and Targeting, University of Groningen, A. Deusinglaan 1, 9713 AV Groningen, The Netherlands
| | - Lena Gustavsson
- Department of Laboratory Medicine (Malmö), Center for Molecular Pathology, Lund University, Jan Waldenströms gata 59, 205 02 Malmö, Sweden
| | - Christelle Guyot
- Department of Clinical Pharmacology and Toxicology, University Hospital, 8091 Zurich, Switzerland
| | - David Hallifax
- Centre for Applied Pharmacokinetic Research (CAPKR), School of Pharmacy and Pharmaceutical Sciences, University of Manchester, Oxford Road, Manchester, M13 9PT UK
| | - Seddik Hammad
- Department of Forensic Medicine and Veterinary Toxicology, Faculty of Veterinary Medicine, South Valley University, Qena, Egypt
| | - Adam Hayward
- Biological and Biomedical Sciences, Durham University, Durham, DH13LE UK
| | - Dieter Häussinger
- Clinic for Gastroenterology, Hepatology and Infectious Diseases, Heinrich-Heine-University, Moorenstrasse 5, 40225 Düsseldorf, Germany
| | - Claus Hellerbrand
- Department of Medicine I, University Hospital Regensburg, 93053 Regensburg, Germany
| | | | - Stefan Hoehme
- Interdisciplinary Center for Bioinformatics (IZBI), University of Leipzig, 04107 Leipzig, Germany
| | - Hermann-Georg Holzhütter
- Institut für Biochemie Abteilung Mathematische Systembiochemie, Universitätsmedizin Berlin (Charité), Charitéplatz 1, 10117 Berlin, Germany
| | - J. Brian Houston
- Centre for Applied Pharmacokinetic Research (CAPKR), School of Pharmacy and Pharmaceutical Sciences, University of Manchester, Oxford Road, Manchester, M13 9PT UK
| | | | - Kiyomi Ito
- Research Institute of Pharmaceutical Sciences, Musashino University, 1-1-20 Shinmachi, Nishitokyo-shi, Tokyo, 202-8585 Japan
| | - Hartmut Jaeschke
- Department of Pharmacology, Toxicology and Therapeutics, University of Kansas Medical Center, Kansas City, KS 66160 USA
| | - Verena Keitel
- Clinic for Gastroenterology, Hepatology and Infectious Diseases, Heinrich-Heine-University, Moorenstrasse 5, 40225 Düsseldorf, Germany
| | | | - B. Kevin Park
- Department of Molecular and Clinical Pharmacology, Centre for Drug Safety Science, Institute of Translational Medicine, University of Liverpool, Liverpool, UK
| | - Claus Kordes
- Clinic for Gastroenterology, Hepatology and Infectious Diseases, Heinrich-Heine-University, Moorenstrasse 5, 40225 Düsseldorf, Germany
| | - Gerd A. Kullak-Ublick
- Department of Clinical Pharmacology and Toxicology, University Hospital, 8091 Zurich, Switzerland
| | - Edward L. LeCluyse
- The Hamner Institutes for Health Sciences, Research Triangle Park, NC USA
| | - Peng Lu
- The Hamner Institutes for Health Sciences, Research Triangle Park, NC USA
| | | | - Anna Lutz
- Department of Pharmaceutical Biology and Biotechnology, University of Freiburg, Freiburg, Germany
| | - Daniel J. Maltman
- Reinnervate Limited, NETPark Incubator, Thomas Wright Way, Sedgefield, TS21 3FD UK
| | - Madlen Matz-Soja
- Institute of Biochemistry, Faculty of Medicine, University of Leipzig, 04103 Leipzig, Germany
| | - Patrick McMullen
- The Hamner Institutes for Health Sciences, Research Triangle Park, NC USA
| | - Irmgard Merfort
- Department of Pharmaceutical Biology and Biotechnology, University of Freiburg, Freiburg, Germany
| | | | - Christoph Meyer
- Department of Medicine II, Section Molecular Hepatology, Medical Faculty Mannheim, Heidelberg University, Mannheim, Germany
| | - Jessica Mwinyi
- Department of Clinical Pharmacology and Toxicology, University Hospital, 8091 Zurich, Switzerland
| | - Dean J. Naisbitt
- Department of Molecular and Clinical Pharmacology, Centre for Drug Safety Science, Institute of Translational Medicine, University of Liverpool, Liverpool, UK
| | - Andreas K. Nussler
- BG Trauma Center, Siegfried Weller Institut, Eberhard Karls University Tübingen, 72076 Tübingen, Germany
| | - Peter Olinga
- Division of Pharmaceutical Technology and Biopharmacy, Department of Pharmacy, University of Groningen, 9713 AV Groningen, The Netherlands
| | - Francesco Pampaloni
- Buchmann Institute for Molecular Life Sciences (BMLS), Goethe University Frankfurt, Max-von-Laue-Str. 15, 60438 Frankfurt am Main, Germany
| | - Jingbo Pi
- The Hamner Institutes for Health Sciences, Research Triangle Park, NC USA
| | - Linda Pluta
- The Hamner Institutes for Health Sciences, Research Triangle Park, NC USA
| | - Stefan A. Przyborski
- Reinnervate Limited, NETPark Incubator, Thomas Wright Way, Sedgefield, TS21 3FD UK
- Biological and Biomedical Sciences, Durham University, Durham, DH13LE UK
| | - Anup Ramachandran
- Department of Pharmacology, Toxicology and Therapeutics, University of Kansas Medical Center, Kansas City, KS 66160 USA
| | - Vera Rogiers
- Department of Toxicology, Centre for Pharmaceutical Research, Faculty of Medicine and Pharmacy, Vrije Universiteit Brussel, 1090 Brussels, Belgium
| | - Cliff Rowe
- Department of Molecular and Clinical Pharmacology, Centre for Drug Safety Science, Institute of Translational Medicine, University of Liverpool, Liverpool, UK
| | - Celine Schelcher
- Department of Surgery, Liver Regeneration, Core Facility, Human in Vitro Models of the Liver, Ludwig Maximilians University of Munich, Munich, Germany
| | - Kathrin Schmich
- Department of Pharmaceutical Biology and Biotechnology, University of Freiburg, Freiburg, Germany
| | - Michael Schwarz
- Department of Toxicology, Institute of Experimental and Clinical Pharmacology and Toxicology, Wilhelmstr. 56, 72074 Tübingen, Germany
| | - Bijay Singh
- Department of Agricultural Biotechnology and Research Institute for Agriculture and Life Sciences, Seoul National University, Seoul, 151-921 Korea
| | - Ernst H. K. Stelzer
- Buchmann Institute for Molecular Life Sciences (BMLS), Goethe University Frankfurt, Max-von-Laue-Str. 15, 60438 Frankfurt am Main, Germany
| | - Bruno Stieger
- Department of Clinical Pharmacology and Toxicology, University Hospital, 8091 Zurich, Switzerland
| | - Regina Stöber
- Leibniz Research Centre for Working Environment and Human Factors (IFADO), 44139 Dortmund, Germany
| | - Yuichi Sugiyama
- Sugiyama Laboratory, RIKEN Innovation Center, RIKEN, Yokohama Biopharmaceutical R&D Center, 1-7-22 Suehiro-cho, Tsurumi-ku, Yokohama, Kanagawa 230-0045 Japan
| | - Ciro Tetta
- Fresenius Medical Care, Bad Homburg, Germany
| | - Wolfgang E. Thasler
- Department of Surgery, Ludwig-Maximilians-University of Munich Hospital Grosshadern, Munich, Germany
| | - Tamara Vanhaecke
- Department of Toxicology, Centre for Pharmaceutical Research, Faculty of Medicine and Pharmacy, Vrije Universiteit Brussel, 1090 Brussels, Belgium
| | - Mathieu Vinken
- Department of Toxicology, Centre for Pharmaceutical Research, Faculty of Medicine and Pharmacy, Vrije Universiteit Brussel, 1090 Brussels, Belgium
| | - Thomas S. Weiss
- Department of Pediatrics and Juvenile Medicine, University of Regensburg Hospital, Regensburg, Germany
| | - Agata Widera
- Leibniz Research Centre for Working Environment and Human Factors (IFADO), 44139 Dortmund, Germany
| | - Courtney G. Woods
- The Hamner Institutes for Health Sciences, Research Triangle Park, NC USA
| | | | | | - Jan G. Hengstler
- Leibniz Research Centre for Working Environment and Human Factors (IFADO), 44139 Dortmund, Germany
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10
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Fleming KE, Wanless IR. Glutamine synthetase expression in activated hepatocyte progenitor cells and loss of hepatocellular expression in congestion and cirrhosis. Liver Int 2013; 33:525-34. [PMID: 23362937 DOI: 10.1111/liv.12099] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/22/2012] [Accepted: 12/07/2012] [Indexed: 12/11/2022]
Abstract
BACKGROUND & AIMS In normal human liver, glutamine synthetase (GS) is expressed in a rim of hepatocytes surrounding hepatic veins. GS expression is decreased in cirrhosis and increased in chronic hepatitis, focal nodular hyperplasia, peritumoural hyperplasia and some hepatocellular neoplasms. For the non-neoplastic conditions, there is limited information available on histological pattern of altered GS expression and the mechanisms of these changes. METHODS We examined GS expression in 58 large specimens and 45 needle biopsies with a variety of non-neoplastic human liver conditions and in 12 normal control livers. Expression was correlated with clinical and histological disease states. RESULTS We identified four patterns of GS expression: (i) Loss of normal perivenular expression was seen in states of chronic congestion, severe cirrhosis and zone 3 necrosis. (ii) Diffuse expression was seen in states with active hepatocellular injury and correlated with Ki-67 expression. (iii) Interface expression was seen in feathery degeneration of chronic cholestasis. (iv) GS expression in activated hepatocyte progenitor cells (HPCs) associated with small ducts and ductules was seen in fulminant hepatic failure and in early and late chronic liver disease and rarely in normal livers. CONCLUSIONS Glutamine synthetase expression is increased in regenerating hepatocytes and in early HPCs prior to morphological evidence of hepatocellular differentiation. This may be the earliest marker of HPCs yet demonstrated. Loss of expression may be a reflection of disrupted endothelium-hepatocyte contact in hepatic vein walls caused by congestive injury as found in congestive heart failure and advanced cirrhosis.
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Affiliation(s)
- Kirsten E Fleming
- Department of Pathology, Queen Elizabeth II Health Sciences Centre, Halifax, NS, Canada
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11
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Phenotype and growth behavior of residual β-catenin-positive hepatocytes in livers of β-catenin-deficient mice. Histochem Cell Biol 2010; 134:469-81. [PMID: 20886225 DOI: 10.1007/s00418-010-0747-1] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 09/20/2010] [Indexed: 12/31/2022]
Abstract
Signaling through the Wnt/β-catenin pathway is a crucial determinant of hepatic zonal gene expression, liver development, regeneration, and tumorigenesis. Transgenic mice with hepatocyte-specific knockout of Ctnnb1 (encoding β-catenin) have proven their usefulness in elucidating these processes. We now found that a small number of hepatocytes escape the Cre-mediated gene knockout in that mouse model. The remaining β-catenin-positive hepatocytes showed approximately 25% higher cell volumes compared to the β-catenin-negative cells and exhibited a marker protein expression profile similar to that of normal perivenous hepatocytes or hepatoma cells with mutationally activated β-catenin. Surprisingly, the expression pattern was observed independent of the cell's position within the liver lobule, suggesting a malfunction of physiological periportal repression of perivenously expressed genes in β-catenin-deficient liver. Clusters of β-catenin-expressing hepatocytes lacked expression of the gap junction proteins Connexin 26 and 32. Nonetheless, β-catenin-positive hepatocytes had no striking proliferative advantage, but started to grow out on treatment with phenobarbital, a tumor-promoting agent known to facilitate the formation of mouse liver adenoma with activating mutations of Ctnnb1. Progressive re-population of Ctnnb1 knockout livers with wild-type hepatocytes was seen in aged mice with a pre-cirrhotic phenotype. In these large clusters of β-catenin-expressing hepatocytes, perivenous-specific gene expression was re-established. In summary, our data demonstrate that the zone-specificity of a hepatocyte's gene expression profile is dependent on the presence of β-catenin, and that β-catenin provides a proliferative advantage to hepatocytes when promoted with phenobarbital, or in a pre-cirrhotic environment.
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12
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Braeuning A, Schwarz M. beta-Catenin as a multilayer modulator of zonal cytochrome P450 expression in mouse liver. Biol Chem 2010; 391:139-148. [PMID: 20030591 DOI: 10.1515/bc.2010.012] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
The liver is the major organ for metabolism of drugs and other xenobiotics. Expression of many drug-metabolizing enzymes is not equally distributed throughout the liver: under normal conditions, many of them, including the most relevant members of the cytochrome P450 superfamily, are exclusively expressed in a hepatocyte subpopulation located near branches of the efferent central vein. Activation of different ligand-dependent transcription factors by exogenous compounds stimulates high expression of certain cytochrome P450 isoforms. This process also occurs preferentially in perivenous hepatocytes. The mechanisms, however, which determine the zone-specificity of basal and xenobiotic-induced expression of cytochrome P450 enzymes, have remained largely unknown for decades. Very recently, signaling through the Wnt/beta-catenin pathway has been implicated in the regulation of zonal gene expression in mouse liver. In this review, current knowledge of cytochrome P450 regulation by beta-catenin-dependent transcription is summarized and underlying molecular mechanisms are discussed.
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Affiliation(s)
- Albert Braeuning
- Department of Toxicology, Institute of Experimental and Clinical Pharmacology and Toxicology, University of Tübingen, Wilhelmstr. 56, D-72074 Tübingen, Germany
| | - Michael Schwarz
- Department of Toxicology, Institute of Experimental and Clinical Pharmacology and Toxicology, University of Tübingen, Wilhelmstr. 56, D-72074 Tübingen, Germany
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13
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Burke ZD, Reed KR, Phesse TJ, Sansom OJ, Clarke AR, Tosh D. Liver zonation occurs through a beta-catenin-dependent, c-Myc-independent mechanism. Gastroenterology 2009; 136:2316-2324.e1-3. [PMID: 19268669 DOI: 10.1053/j.gastro.2009.02.063] [Citation(s) in RCA: 126] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/10/2008] [Revised: 01/05/2009] [Accepted: 02/26/2009] [Indexed: 12/23/2022]
Abstract
BACKGROUND AND AIMS The Wnt pathway has previously been shown to play a role in hepatic zonation. Herein, we have explored the role of 3 key components (Apc, beta-catenin, and c-Myc) of the Wnt pathway in the zonation of ammonia metabolizing enzymes. METHODS Conditional deletion of Apc, beta-catenin, and c-Myc was induced in the livers of mice and the expression of periportal and perivenous hepatocyte markers was determined by polymerase chain reaction, Western blotting, and immunohistochemical techniques. RESULTS Under normal circumstances, the urea cycle enzyme carbamoylphosphate synthetase I (CPS I) is present in the periportal, intermediate, and the first few layers of the perivenous zone. In contrast, glutamine synthetase (GS)--and nuclear beta-catenin--is expressed in a complementary fashion in the last 1-2 cell layers of the perivenous zone. Conditional loss of Apc resulted in the expression of nuclear beta-catenin and GS in most hepatocytes irrespective of zone. Induction of GS in hepatocytes outside the normal perivenous zone was accompanied by a reduction in the expression of CPS I. Deletion of beta-catenin induces a loss of GS and a complementary increase in expression of CPS I irrespective of whether Apc is present. Remarkably, deletion of c-Myc did not perturb the pattern of zonation. CONCLUSIONS It has been shown that the Wnt pathway is key to imposing the pattern of zonation within the liver. Herein we have addressed the relevance of 3 major Wnt pathway components and show critically that the zonation is c-Myc independent but beta-catenin dependent.
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Affiliation(s)
- Zoé D Burke
- Centre for Regenerative Medicine, Department of Biology & Biochemistry, University of Bath, Claverton Down, Bath, UK
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14
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Dekaney CM, Wu G, Yin YL, Jaeger LA. Regulation of ornithine aminotransferase gene expression and activity by all-transretinoic acid in Caco-2 intestinal epithelial cells. J Nutr Biochem 2008; 19:674-81. [DOI: 10.1016/j.jnutbio.2007.09.002] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2007] [Revised: 08/14/2007] [Accepted: 09/04/2007] [Indexed: 10/22/2022]
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15
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Ohno H, Naito Y, Nakajima H, Tomita M. Construction of a biological tissue model based on a single-cell model: a computer simulation of metabolic heterogeneity in the liver lobule. ARTIFICIAL LIFE 2008; 14:3-28. [PMID: 18171128 DOI: 10.1162/artl.2008.14.1.3] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/25/2023]
Abstract
An enormous body of information has been obtained by molecular and cellular biology in the last half century. However, even these powerful approaches are not adequate when it comes to higher-level biological structures, such as tissues, organs, and individual organisms, because of the complexities involved. Thus, accumulation of data at the higher levels supports and broadens the context for that obtained on the molecular and cellular levels. Under such auspices, an attempt to elucidate mesoscopic and macroscopic subjects based on plentiful nanoscopic and microscopic data is of great potential value. On the other hand, fully realistic simulation is impracticable because of the extensive cost entailed and enormous amount of data required. Abstraction and modeling that balance the dual requirements of prediction accuracy and manageable calculation cost are of great importance for systems biology. We have constructed an ammonia metabolism model of the hepatic lobule, a histological component of the liver, based on a single-hepatocyte model that consists of the biochemical kinetics of enzymes and transporters. To bring the calculation cost within reason, the porto-central axis, which is an elemental structure of the lobule, is defined as the systems biological unit of the liver, and is accordingly modeled. A model including both histological structure and position-specific gene expression of major enzymes largely represents the physiological dynamics of the hepatic lobule in nature. In addition, heterogeneous gene expression is suggested to have evolved to optimize the energy efficiency of ammonia detoxification at the macroscopic level, implying that approaches like this may elucidate how properties at the molecular and cellular levels, such as regulated gene expression, modify higher-level phenomena of multicellular tissue, organs, and organisms.
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Affiliation(s)
- Hiroshi Ohno
- Institute for Advanced Biosciences, Keio University, 14-1 Baba-cho, Tsuruoka, 997-0035, Japan.
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16
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Gebhardt R, Baldysiak-Figiel A, Krügel V, Ueberham E, Gaunitz F. Hepatocellular expression of glutamine synthetase: an indicator of morphogen actions as master regulators of zonation in adult liver. ACTA ACUST UNITED AC 2007; 41:201-66. [PMID: 17368308 DOI: 10.1016/j.proghi.2006.12.001] [Citation(s) in RCA: 87] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Glutamine synthetase (GS) has long been known to be expressed exclusively in pericentral hepatocytes most proximal to the central veins of liver lobuli. This enzyme as well as its peculiar distribution complementary to the periportal compartment for ureogenesis plays an important role in nitrogen metabolism, particularly in homeostasis of blood levels of ammonium ions and glutamine. Despite this fact and intensive studies in vivo and in vitro, many aspects of the regulation of its activity on the protein and on the genetic level remained enigmatic. Recent experimental advances using transgenic mice and new analytic tools have revealed the fundamental role of morphogens such as wingless-type MMTV integration site family member signals (Wnt), beta-catenin, and adenomatous polyposis coli in the regulation of this particular enzyme. In addition, novel information concerning the structure of transcription factor binding sites within regulatory regions of the GS gene and their interactions with signalling pathways could be collected. In this review we focus on all aspects of the regulation of GS in the liver and demonstrate how the new findings have changed our view of the determinants of liver zonation. What appeared as a simple response of hepatocytes to blood-derived factors and local cellular interactions must now be perceived as a fundamental mechanism of adult tissue patterning by morphogens that were considered mainly as regulators of developmental processes. Though GS may be the most obvious indicator of morphogen action among many other targets, elucidation of the complex regulation of the expression of the GS gene could pave the road for a better understanding of the mechanisms involved in patterning of liver parenchyma. Based on current knowledge we propose a new concept of how morphogens, hormones and other factors may act in concert, in order to restrict gene expression to small subpopulations of one differentiated cell type, the hepatocyte, in different anatomical locations. Although many details of this regulatory network are still missing, and an era of exciting new discoveries is still about to come, it can already be envisioned that similar mechanisms may well be active in other organs contributing to the fine-tuning of organ-specific functions.
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Affiliation(s)
- Rolf Gebhardt
- Institut für Biochemie, Medizinische Fakultät, Universität Leipzig, Johannisallee 30, 04103 Leipzig, Germany.
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17
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Hailfinger S, Jaworski M, Braeuning A, Buchmann A, Schwarz M. Zonal gene expression in murine liver: lessons from tumors. Hepatology 2006; 43:407-14. [PMID: 16496347 DOI: 10.1002/hep.21082] [Citation(s) in RCA: 114] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Gene expression in hepatocytes within the liver lobule is differentially regulated along the portal to central axis; however, the mechanisms governing the processes of zonation within the lobule are unknown. A model for zonal heterogeneity in normal liver is proposed, based on observations of differential expression of genes in liver tumors from mice that harbor activating mutations in either Catnb (which codes for beta-catenin) or Ha-ras. According to the model, the regulatory control consists of two opposing signals, one delivered by endothelial cells of the central veins activating a beta-catenin-dependent pathway (retrograde signal), the other by blood-borne molecules activating Ras-dependent downstream cascades (anterograde signal). In conclusion, gradients of opposing signaling molecules along the portocentral axis determine the pattern of enzymes and other proteins expressed in hepatocytes of the periportal and pericentral domains of the liver lobule.
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Affiliation(s)
- Stephan Hailfinger
- Institute of Pharmacology and Toxicology, Department of Toxicology, University of Tuebingen, Germany
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18
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Gieling RG, Ruijter JM, Maas AAW, Van Den Bergh Weerman MA, Dingemans KP, ten Kate FJW, Lekanne dit Deprez RH, Moorman AFM, Lamers WH. Hepatic response to right ventricular pressure overload. Gastroenterology 2004; 127:1210-21. [PMID: 15480998 DOI: 10.1053/j.gastro.2004.07.057] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
Abstract
BACKGROUND & AIMS Modifying the afferent blood supply to the liver does not change the zonal expression pattern of hepatic enzymes in the rat. METHODS We used pulmonary trunk banding (PTB) to study the effect of an efferent hindrance of blood flow on hepatic architecture and zonation of gene expression. RESULTS Most PTB rats developed right ventricular hypertrophy and congestive heart failure. The hepatic response to PTB developed concomitantly with the decline in heart function. Enzyme expression in the periportal region was not affected, but the pericentral rim of hepatocytes expressing glutamine synthetase, ornithine aminotransferase, and NADPH cytochrome P-450 reductase (CYPred) first declined in diameter, then became discontinuous, and finally disappeared. Meanwhile, ornithine aminotransferase and especially CYPred, became re-expressed in the periportal zone. These changes occurred without appreciable cell death or fibrotic changes; the expression of fibronectin and alpha-smooth muscle actin increased perisinusoidally, but that of collagen did not. Electron microscopic analysis revealed normal fenestration of the sinusoidal endothelial cells without detectable deposition of basement membrane material, but both the width of the space of Disse and the length and number of hepatic microvilli were significantly reduced, implying a decreased flow of fluid in the space of Disse. CONCLUSIONS The reprogramming of gene expression in livers with a postsinusoidal hindrance of blood flow results from declining access of the hepatocytes to intrasinusoidal signal-transduction molecules and suggest that the impaired biotransformation that accompanies right ventricular failure is caused by a central-to-portal shift in expression of the corresponding enzymes.
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Affiliation(s)
- Roben G Gieling
- AMC Liver Center, Academic Medical Center, University of Amsterdam, The Netherlands
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19
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Cadoret A, Ovejero C, Terris B, Souil E, Lévy L, Lamers WH, Kitajewski J, Kahn A, Perret C. New targets of beta-catenin signaling in the liver are involved in the glutamine metabolism. Oncogene 2002; 21:8293-301. [PMID: 12447692 DOI: 10.1038/sj.onc.1206118] [Citation(s) in RCA: 315] [Impact Index Per Article: 14.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2002] [Revised: 10/01/2002] [Accepted: 10/08/2002] [Indexed: 02/07/2023]
Abstract
Inappropriate activation of the Wnt/beta-catenin signaling has been implicated in the development of hepatocellular carcinoma (HCC), but exactly how beta-catenin works remains to be elucidated. To identify, in vivo, the target genes of beta-catenin in the liver, we have used the suppression subtractive hybridization technique and transgenic mice expressing an activated beta-catenin in the liver that developed hepatomegaly. We identified three genes involved in glutamine metabolism, encoding glutamine synthetase (GS), ornithine aminotransferase (OAT) and the glutamate transporter GLT-1. By Northern blot and immunohistochemical analysis we demonstrated that these three genes were specifically induced by activation of the beta-catenin pathway in the liver. In different mouse models bearing an activated beta-catenin signaling in the liver known to be associated with hepatocellular proliferation we observed a marked up-regulation of these three genes. The cellular distribution of GS and GLT-1 parallels beta-catenin activity. By contrast no up-regulation of these three genes was observed in the liver in which hepatocyte proliferation was induced by a signal-independent of beta-catenin. In addition, the GS promoter was activated in the liver of GS(+/LacZ) mice by adenovirus vector-mediated beta-catenin overexpression. Strikingly, the overexpression of the GS gene in human HCC samples was strongly correlated with beta-catenin activation. Together, our results indicate that GS is a target of the Wnt/beta-catenin pathway in the liver. Because a linkage of the glutamine pathway to hepatocarcinogenesis has already been demonstrated, we propose that regulation of these three genes of glutamine metabolism by beta-catenin is a contributing factor to liver carcinogenesis.
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Affiliation(s)
- Axelle Cadoret
- Département de Génétique, Développement et Pathologie Moléculaire, Institut Cochin, (INSERM U567, CNRS UMR 8104, Université Paris V), 24 rue du Faubourg St-Jacques, 75014 Paris, France
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20
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Osada T, Nagashima I, Tsuno NH, Kitayama J, Nagawa H. Prognostic significance of glutamine synthetase expression in unifocal advanced hepatocellular carcinoma. J Hepatol 2000; 33:247-53. [PMID: 10952242 DOI: 10.1016/s0168-8278(00)80365-7] [Citation(s) in RCA: 42] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
BACKGROUND/AIMS Glutamine synthetase (GS) catalyzes the synthesis of glutamine, a major energy source of cells, and is upregulated in a subset of human hepatocellular carcinomas (HCCs). GS expression may be related to tumor recurrence, since GS-expressing tumors have a growth advantage in that they are independent of the extracellular glutamine supply. However, there are no studies concerning the prognostic value of GS expression in patients with HCC. METHODS Seventy-three patients with a single advanced HCC nodule who underwent curative hepatectomy were included in the study. GS expression in the HCC nodules was analyzed immunohistochemically and was compared with clinicopathologic features and the behavior of the tumors. Survival curves were assessed according to the Kaplan-Meier product-limit method and multivariate analysis based on the Cox regression model was performed. RESULTS GS expression was strong in 26 cases (35.6%, high-GS group) and weak or absent in 47 cases (64.4%, low-GS group). Univariate analysis showed that the high-GS group had a significantly shorter disease-free survival time than the low-GS group (p=0.042). Multivariate analysis revealed that GS expression (p=0.021), as well as Child's classification (p=0.005) and portal invasion (p=0.039), was a significant and independent prognostic parameter that affected tumor recurrence. CONCLUSION The results of this study indicate that GS expression may enhance the metastatic potential in HCC, and GS immunostaining may be helpful in identifying HCC patients at high risk for disease recurrence.
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Affiliation(s)
- T Osada
- Department of Surgical Oncology, Graduate School of Medicine, University of Tokyo, Japan.
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Yamashita T, Hashimoto S, Kaneko S, Nagai S, Toyoda N, Suzuki T, Kobayashi K, Matsushima K. Comprehensive gene expression profile of a normal human liver. Biochem Biophys Res Commun 2000; 269:110-6. [PMID: 10694486 DOI: 10.1006/bbrc.2000.2272] [Citation(s) in RCA: 61] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
To investigate the gene expression profile of a normal human liver, we performed serial analysis of gene expression (SAGE), which allows the quantitative and simultaneous analysis of thousands of genes expressed in tissue. Polyadenylated RNA was obtained from a bulk normal human liver sample and SAGE was performed. Reverse transcriptase-polymerase chain reaction (RT-PCR) was also performed in each of 3 different normal liver samples to evaluate the validity of the profile in each individual. A total of 30,982 tags were sequenced, 8,596 of which were unique. The genes highly expressed in the normal liver were those encoding plasma proteins (>21.8% of total transcripts), cytoplasmic proteins (>8.6%), enzymes (>4.8%), protease inhibitors (>1.7%), complements (>1.1%), and coagulation factors (>0.75%). About 13.9% of all transcripts encoded genes not reported in GenBank thus far. This study identifies candidate genes to be examined in relation to various human liver diseases, including viral hepatitis, liver cirrhosis, and hepatocellular carcinoma.
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Affiliation(s)
- T Yamashita
- First Department of Internal Medicine & CREST, School of Medicine, University of Kanazawa, 13-1 Takara-Machi, Kanazawa, Ishikawa, 920-8641, Japan
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Bode JG, Peters-Regehr T, Kubitz R, Häussinger D. Expression of glutamine synthetase in macrophages. J Histochem Cytochem 2000; 48:415-22. [PMID: 10681395 DOI: 10.1177/002215540004800311] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Abstract
We studied the expression of glutamine synthetase in liver macrophages (Kupffer cells, KCs) in situ and in culture. Glutamine synthetase was detectable at the mRNA and protein level in freshly isolated and short-term-cultured rat liver macrophages. Enzyme activity and protein content were about 9% of that in liver parenchymal cells. In contrast, glutamine synthetase mRNA levels in liver macrophages apparently exceeded those in parenchymal liver cells (PCs). By use of confocal laser scanning microscopy and specific macrophage markers, immunoreactive glutamine synthetase was localized to macrophages in normal rat liver and normal human liver in situ. All liver macrophages stained positive for glutamine synthetase. In addition, macrophages in rat pancreas contained immunoreactive glutamine synthetase, whereas glutamine synthetase was not detectable at the mRNA and protein level in blood monocytes and RAW 264.7 mouse macrophages. No significant amounts of glutamine synthetase were found in isolated rat liver sinusoidal endothelial cells (SECs). The data suggest a constitutive expression of glutamine synthetase not only, as previously believed, in perivenous liver parenchymal cells but also in resident liver macrophages.
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Affiliation(s)
- J G Bode
- Medizinische Universitätsklinik, Klinik für Gastroenterologie, Hepatologie und Infektiologie, Heinrich-Heine Universität, Düsseldorf, Germany
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Christoffels VM, Sassi H, Ruijter JM, Moorman AF, Grange T, Lamers WH. A mechanistic model for the development and maintenance of portocentral gradients in gene expression in the liver. Hepatology 1999; 29:1180-92. [PMID: 10094963 DOI: 10.1002/hep.510290413] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Abstract
In the liver, genes are expressed along a portocentral gradient. Based on their adaptive behavior, a gradient versus compartment type, and a dynamic versus stable type of gradient have been recognized. To understand at least in principle the development and maintenance of these gradients in gene expression in relation to the limited number of signal gradients, we propose a simple and testable model. The model uses portocentral gradients of signal molecules as input, while the output depends on two gene-specific variables, viz., the affinity of the gene for its regulatory factors and the degree of cooperativity that determines the response in the signal-transduction pathways. As a preliminary validity test for its performance, the model was tested on control and hormonally induced expression patterns of phosphoenolpyruvate carboxykinase (PCK), carbamoylphosphate synthetase I (CPS), and glutamine synthetase (GS). Affinity was found to determine the overall steepness of the gradient, whereas cooperativity causes these gradients to steepen locally, as is necessary for a compartment-like expression pattern. Interaction between two or more different signal gradients is necessary to ensure a stable expression pattern under different conditions. The diversity in sequence and arrangement of related DNA-response elements of genes appears to account for the gene-specific shape of the portocentral gradients in expression. The feasibility of testing the function of hepatocyte-specific DNA-response units in vivo is demonstrated by integrating such units into a ubiquitously active promoter/enhancer and analyzing the pattern of expression of these constructs in transgenic mice.
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Affiliation(s)
- V M Christoffels
- Department of Anatomy and Embryology, Academic Medical Center, University of Amsterdam, Amsterdam, the Netherlands
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Osada T, Sakamoto M, Nagawa H, Yamamoto J, Matsuno Y, Iwamatsu A, Muto T, Hirohashi S. Acquisition of glutamine synthetase expression in human hepatocarcinogenesis: relation to disease recurrence and possible regulation by ubiquitin-dependent proteolysis. Cancer 1999; 85:819-31. [PMID: 10091759 DOI: 10.1002/(sici)1097-0142(19990215)85:4<819::aid-cncr9>3.0.co;2-e] [Citation(s) in RCA: 47] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
BACKGROUND The authors previously reported increased ubiquitin (Ub) immunoreactivity in hepatocellular carcinomas (HCCs) and suggested a possible correlation between changes in ubiquitinated protein levels and multistep hepatocarcinogenesis. The current study was performed to identify one of these ubiquitinated proteins (42 kDa) and to analyze the clinical significance of its accumulation. METHODS The protein was purified using two-dimensional gel electrophoresis and identified by amino acid sequence analysis. The authors studied the expression of this protein in 101 HCCs and 23 precancerous lesions by immunohistochemical methods and in 26 HCCs by immunoblot analysis. A survival analysis was performed on patients with advanced HCC using the Kaplan-Meier method with approximate chi-square statistics for the log rank test. RESULTS The target protein for ubiquitination was identified as glutamine synthetase (GS). Accumulation of GS was found in 19 of 49 advanced HCCs (38.8%) by immunohistochemical methods and in 9 of 16 (56.3%) by immunoblot analysis, whereas the frequency was much lower in early HCCs (12.9% and 33.3%, respectively) and precancerous lesions (4.3% by immunostaining). In the Ub immunoblot analysis of strongly GS positive specimens, an intense 42-kDa ubiquitinated band was observed. Nine of 21 (42.9%) nodule-in-nodule type HCCs showed a GS positive, high-grade component within a GS negative, low-grade component, indicating the acquisition of GS expression during progression. Among 23 patients with a single advanced HCC nodule, the relapse free survival time was significantly shorter in the GS positive group than in the GS negative group. CONCLUSIONS The results of this study demonstrate the acquisition of GS expression during hepatocarcinogenesis and the possible regulation of GS enzyme activity by a Ub-dependent proteolytic system. Moreover, GS might play a significant role in promoting the metastatic potential of HCC.
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Affiliation(s)
- T Osada
- Pathology Division, National Cancer Center Research Institute, Tokyo, Japan
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25
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Gupta S, Rajvanshi P, Sokhi RP, Vaidya S, Irani AN, Gorla GR. Position-specific gene expression in the liver lobule is directed by the microenvironment and not by the previous cell differentiation state. J Biol Chem 1999; 274:2157-65. [PMID: 9890978 DOI: 10.1074/jbc.274.4.2157] [Citation(s) in RCA: 49] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Mechanisms directing position-specific liver gene regulation are incompletely understood. To establish whether this aspect of hepatic gene expression is an inveterate phenomenon, we used transplanted hepatocytes as reporters in dipeptidyl peptidase IV-deficient F344 rats. After integration in liver parenchyma, the position of transplanted cells was shifted from periportal to perivenous areas by targeted hepatic ablations with carbon tetrachloride. In controls, transplanted cells showed greater glucose-6-phosphatase and lesser glycogen content in periportal areas. This pattern was reversed when transplanted cells shifted from periportal to perivenous areas. Transplanted hepatocytes in perivenous areas exhibited inducible cytochrome P450 activity, which was deficient in periportal hepatocytes. Moreover, cytochrome P450 activity was rapidly extinguished in activated hepatocytes when these cells were transplanted into the nonpermissive liver of suckling rat pups. In cells isolated from the normal F344 rat liver, cytochrome P450 inducibility was originally greater in perivenous hepatocytes; however, periportal cells rapidly acquired this facility in culture conditions. These findings indicate that the liver microenvironment exerts supremacy over prior differentiation state of cells in directing position-specific gene expression. Therefore, persistence of specialized hepatocellular function will require interactions with regulatory signals and substrate availability, which bears upon further analysis of liver gene regulation, including in progenitor and/or stem cells.
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Affiliation(s)
- S Gupta
- Marion Bessin Liver Research Center, Albert Einstein College of Medicine, Bronx, New York 10461, USA
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26
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Rajvanshi P, Liu D, Ott M, Gagandeep S, Schilsky ML, Gupta S. Fractionation of rat hepatocyte subpopulations with varying metabolic potential, proliferative capacity, and retroviral gene transfer efficiency. Exp Cell Res 1998; 244:405-19. [PMID: 9806791 DOI: 10.1006/excr.1998.4223] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
The liver contains hepatocytes with varying ploidy and gene expression. To isolate cells on the basis of ploidy for analyzing mechanisms concerning cell proliferation and differentiation, we used Percoll gradients to separate F344 rat hepatocyte subpopulations. Specific fractions were enriched in polyploid (H2 fraction) or diploid (H3 and H4 fractions) hepatocytes containing glycogen and glucose-6-phosphatase. H4 cells were relatively smaller with greater nuclear/cytoplasmic ratios, less complex cytoplasm, and higher serum albumin or ceruloplasmin biosynthetic rates. H2 fraction cells were larger with lesser nuclear/cytoplasmic ratio, more complex cytoplasm, and more cytochrome P450 activity. Phenotypic marking showed that H4 cells originated in zone one and H2 cells in zones two or three of the liver lobule. H4 cells showed much greater mitogenic responsiveness to human hepatocyte growth factor. Retroviral gene transfer, which requires both viral receptors and cellular DNA synthesis, was significantly more efficient in H4 cells. The findings indicated that small diploid and large polyploid hepatocytes show unique biological differences. The ability to isolate hepatocytes of varying maturity is relevant for mechanisms concerning liver growth control and hepatic gene expression.
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Affiliation(s)
- P Rajvanshi
- Division of Gastroenterology, Marion Bessin Liver Research Center, Bronx, New York, 10461, USA
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27
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Massimi M, Lear SR, Huling SL, Jones AL, Erickson SK. Cholesterol 7alpha-hydroxylase (CYP7A): patterns of messenger RNA expression during rat liver development. Hepatology 1998; 28:1064-72. [PMID: 9755244 DOI: 10.1002/hep.510280422] [Citation(s) in RCA: 36] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
Cholesterol 7-hydroxylase is a rate-limiting enzyme in bile acid synthesis, a major pathway for cholesterol catabolism. It plays a crucial role in postnatal development and survival. In an adult liver, its activity and messenger RNA (mRNA) are heterogeneously distributed with concentration in the pericentral area. We defined how the pattern of cholesterol 7-hydroxylase mRNA evolves during rat liver development, correlated this with its total liver mRNA levels, and determined when its heterogeneous pattern of expression is established. Cholesterol 7-hydroxylase mRNA was undetectable in 18-day-old fetal livers by Northern blot. It was increased markedly in newborns with a homogeneous liver lobular distribution as determined by in situ hybridization. At postnatal day four, mRNA levels were markedly decreased with concomitant appearance of a lobular gradient: mRNA was detected only in a few hepatocytes located around efferent venules. At 22 days, the time of highest mRNA expression, a marked extension of the gradient towards the periportal area was observed, indicating that the increase in total liver cholesterol 7-hydroxylase mRNA level was a result of recruitment of hepatocytes upstream from the central vein area. By 28 days, the adult pattern was observed. Thus, expression of cholesterol 7-hydroxylase mRNA is tightly regulated during rat liver development, both temporally and spatially supporting its critical role in normal postnatal development.
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Affiliation(s)
- M Massimi
- Department of Medicine, University of California, San Francisco, CA 94121, USA
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28
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Lie-Venema H, Hakvoort TB, van Hemert FJ, Moorman AF, Lamers WH. Regulation of the spatiotemporal pattern of expression of the glutamine synthetase gene. PROGRESS IN NUCLEIC ACID RESEARCH AND MOLECULAR BIOLOGY 1998; 61:243-308. [PMID: 9752723 DOI: 10.1016/s0079-6603(08)60829-6] [Citation(s) in RCA: 40] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
Glutamine synthetase, the enzyme that catalyzes the ATP-dependent conversion of glutamate and ammonia into glutamine, is expressed in a tissue-specific and developmentally controlled manner. The first part of this review focuses on its spatiotemporal pattern of expression, the factors that regulate its levels under (patho)physiological conditions, and its role in glutamine, glutamate, and ammonia metabolism in mammals. Glutamine synthetase protein stability is more than 10-fold reduced by its product glutamine and by covalent modifications. During late fetal development, translational efficiency increases more than 10-fold. Glutamine synthetase mRNA stability is negatively affected by cAMP, whereas glucocorticoids, growth hormone, insulin (all positive), and cAMP (negative) regulate its rate of transcription. The signal transduction pathways by which these factors may regulate the expression of glutamine synthetase are briefly discussed. The second part of the review focuses on the evolution, structure, and transcriptional regulation of the glutamine synthetase gene in rat and chicken. Two enhancers (at -6.5 and -2.5 kb) were identified in the upstream region and two enhancers (between +156 and +857 bp) in the first intron of the rat glutamine synthetase gene. In addition, sequence analysis suggests a regulatory role for regions in the 3' untranslated region of the gene. The immediate-upstream region of the chicken glutamine synthetase gene is responsible for its cell-specific expression, whereas the glucocorticoid-induced developmental appearance in the neural retina is governed by its far-upstream region.
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Affiliation(s)
- H Lie-Venema
- Department of Anatomy and Embryology, University of Amsterdam, The Netherlands
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29
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Häussinger D. Hepatic glutamine transport and metabolism. ADVANCES IN ENZYMOLOGY AND RELATED AREAS OF MOLECULAR BIOLOGY 1998; 72:43-86. [PMID: 9559051 DOI: 10.1002/9780470123188.ch3] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
Although the liver was long known to play a major role in the uptake, synthesis, and disposition of glutamine, metabolite balance studies across the whole liver yielded apparently contradictory findings suggesting that little or no net turnover of glutamine occurred in this organ. Efforts to understand the unique regulatory properties of hepatic glutaminase culminated in the conceptual reformulation of the pathway for glutamine synthesis and turnover, especially as regards the role of sub-acinar distribution of glutamine synthetase and glutaminase. This chapter describes these processes as well as the role of glutamine in hepatocellular hydration, a process that is the consequence of cumulative, osmotically active uptake of glutamine into cells. This topic is also examined in terms of the effects of cell swelling on the selective stimulation or inhibition of other far-ranging cellular processes. The pathophysiology of the intercellular glutamine cycle in cirrhosis is also considered.
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Affiliation(s)
- D Häussinger
- Medizinische Universitätsklinik, Heinrich-Heine-Universität Düsseldorf, Germany
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30
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Shiojiri N, Wada J, Gebhardt R. Heterogeneous carbamoylphosphate synthetase I expression in testicular transplants of fetal mouse liver. Eur J Cell Biol 1998; 75:389-92. [PMID: 9628326 DOI: 10.1016/s0171-9335(98)80073-3] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
Expression of carbamoylphosphate synthetase I (CPSI; EC 6.3.4.16) was examined immunohistochemically in normal development of the mouse liver, and in testicular transplants of fetal liver fragments. CPSI started to be expressed in all hepatocytes around 15 days of gestation, and became heterogeneous (i.e. absent from pericentral hepatocytes) around 2 weeks after birth. Most hepatocytes in fetal liver fragments placed for 2 months under the testicular capsule expressed this enzyme except for the pericentral ones, most of which were positively stained with anti-glutamine synthetase (GS; EC 6.3.1.2) antiserum. This distribution resembled that in the adult liver. The steep change in CPSI immunostaining in liver lobules suggests that the microenvironment tightly connected to the central veins plays an important role in the suppression of CPSI expression in the pericentral hepatocytes. Some pericentral hepatocytes were also negative for both enzymes. Thus, control mechanisms of CPSI expression may be different from those of GS expression in pericentral hepatocytes.
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Affiliation(s)
- N Shiojiri
- Department of Biology, Faculty of Science, Shizuoka University, Oya, Japan
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31
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Lie-Venema H, de Boer PA, Moorman AF, Lamers WH. Organ-specific activity of the 5' regulatory region of the glutamine synthetase gene in developing mice. EUROPEAN JOURNAL OF BIOCHEMISTRY 1997; 248:644-59. [PMID: 9342214 DOI: 10.1111/j.1432-1033.1997.00644.x] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
Glutamine synthetase (GS) converts ammonia and glutamate into glutamine. We assessed the activity of the 5' regulatory region of the GS gene in developing transgenic mice carrying the chloramphenicol acetyltransferase (CAT) gene under the control of 3150 bp of the upstream sequence of the rat GS gene to obtain insight into the spatiotemporal regulation of its pattern of expression. To determine the organ-specific activity of the 5' regulatory region CAT and GS mRNA expression were compared by ribonuclease-protection and semi-quantitative in situ hybridization analyses. Three patterns were observed: the 5' region is active and involved in the regulation of GS expression throughout development (pericentral hepatocytes, intestines and epididymis); the 5' region shows no activity at any of the ages investigated (periportal hepatocytes and white adipose tissue); and the activity of the 5' region becomes repressed during development (stomach, muscle, brown adipose tissue, kidney, lung and testis). In the second group, an additional element must be responsible for the activation of GS expression. The last group included organs in which the 5' regulatory region is active, but not in the cells that express GS. In these organs, the activity of the 5' regulatory region must be repressed by other regulatory regions of the GS gene that are missing from the transgenic construct. These findings indicate that in addition to the 5' regulatory region, at least two unidentified elements are involved in the spatiotemporal pattern of expression of GS.
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Affiliation(s)
- H Lie-Venema
- Department of Anatomy and Embryology, University of Amsterdam, Academic Medical Center, The Netherlands
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32
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Segal JA, Schulte PM, Powers DA, Crawford DL. Descriptive and functional characterization of variation in the Fundulus heteroclitus Ldh-B proximal promoter. THE JOURNAL OF EXPERIMENTAL ZOOLOGY 1996; 275:355-64. [PMID: 8691188 DOI: 10.1002/(sici)1097-010x(19960801)275:5<355::aid-jez4>3.0.co;2-o] [Citation(s) in RCA: 21] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
Variation in enzyme expression may be an important mechanism for physiological and evolutionary adaptation. The Ldh-B locus in the teleost fish Fundulus heteroclitus is one of a very few loci for which an evolutionary difference in transcription rate between populations has been demonstrated. To begin to understand the molecular modifications that are responsible for altering transcription, we have characterized the Ldh-B proximal promoter using a combination of sequence analysis, transient transfection, and in vivo footprinting. The Ldh-B gene has several transcription start sites and a TATA-less, Inr (initiator of transcription motif) containing promoter with multiple Sp1-like motifs. Transfection experiments reveal that Sp1 sites, TCC repeats, and Inrs are functional components of the proximal promoter. We find substantial sequence variation between populations within the proximal promoter (250 bp from the transcription start sites) and footprinting analysis indicates that some of this sequence variation is associated with differential protein binding to the apparent TFIID binding site and Sp1 sites. Together, these data suggest that variation in the Ldh-B proximal promoter may play a role in the observed difference in transcription rates between northern and southern populations of F. heteroclitus.
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Affiliation(s)
- J A Segal
- Department of Organismal Biology and Anatomy, University of Chicago, Illinois 60637, USA
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33
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Sirma H, Williams GM, Gebhardt R. Strain- and sex-specific variations in hepatic glutamine synthetase activity and distribution in rats and mice. LIVER 1996; 16:166-73. [PMID: 8873003 DOI: 10.1111/j.1600-0676.1996.tb00723.x] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
The distribution of glutamine synthetase (GS) in a mammalian liver is restricted to a small zone of hepatocytes surrounding the central veins. The determination of the size of the GS+ zone in rats by immunohistochemistry revealed that it differed between rat strains and was larger in males than in females of each strain. Accordingly, the means of the relative mean width (RMW) values that characterize the size of the GS+ zone were 19%, 26%, and 39% lower in females than in males of Sprague-Dawley, Wistar, and Fischer rats, respectively. Upon orchidectomy of male rats, the size of the GS+ zone diminished towards the value found in females, while ovariectomy was without effect. This orchidectomy-induced reduction was reflected in corresponding changes of the RMW values as well as in the number of GS+ cells per pericentral field and was not due to the slightly smaller size of the GS+ hepatocytes in the orchidectomized males. No such sex difference was found in M775 mice. Biochemical GS activity was higher in the male rats than in the female rats and changed correspondingly to the distribution after gonadectomy. In the mice, only the specific activity of GS dropped after orchidectomy. In primary cultures of rat hepatocytes, no influence of testosterone or estrogen on GS activity and cellular distribution was observed, even after stimulation of GS activity with dexamethasone and growth hormone. Both sex hormones, however, were able to affect the activity of glucose-6-phosphate dehydrogenase (G6PD). The observed sex differences in the activity and distribution of GS in rat livers suggest that sex hormones not only modulate the level of this enzyme but are at least partially involved in the determination of the size of the compartment of GS expression. According to the results in the cell cultures, the effects of the sex hormones appear indirect rather than direct.
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Affiliation(s)
- H Sirma
- Physiologisch-Chemisches Institut, Universität Tubingan, FRG
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34
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Sabourin JC, Kern AS, Grégori C, Porteu A, Cywiner C, Châtelet FP, Kahn A, Pichard AL. An intronic enhancer essential for tissue-specific expression of the aldolase B transgenes. J Biol Chem 1996; 271:3469-73. [PMID: 8631949 DOI: 10.1074/jbc.271.7.3469] [Citation(s) in RCA: 21] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023] Open
Abstract
Expression in mice of transgenes directed by regulatory regions of the rat aldolase B gene requires the presence of a B element located in the first intron, while constructs devoid of this intronic enhancer are silent. Histo- and immunochemical staining of transgenic tissue sections showed that the longer transgene was expressed in the proximal tubular cells of the kidney, enterocytes located in small intestine villi and liver parenchymal cells. In the liver, a maximal expression was observed in perivenous hepatocytes, while the transgene was weakly active in periportal hepatocytes, which reproduced the pattern of functional zonation already reported for other glycolytic and gluconeogenic genes in the liver. We also established that the transgene retained the necessary elements for a correct chronological expression during development but was lacking elements necessary for activation by high carbohydrate diet. Instead, transgene expression was paradoxically stimulated in fasted animals, suggesting that the endogenous gene, which must be active under both glycolytic and gluconeogenic conditions, could possess distinct elements activating it in fasted as well as in carbohydrate-fed animals; the former element might be conserved in the transgene and the latter one might be lost.
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Affiliation(s)
- J C Sabourin
- Laboratoire de Biologie Moléculaire Morphologique, Centre Hospitalo Universitaire Saint Antoine, 27, rue de Chaligny, 75012 Paris, France
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35
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Shull JD, Esumi N, Colwell AS, Pennington KL, Jendoubi M. Sequence of the promoter region of the mouse gene encoding ornithine aminotransferase. Gene 1995; 162:275-7. [PMID: 7557443 DOI: 10.1016/0378-1119(95)00309-t] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Abstract
We have isolated and sequenced the promoter region of the mouse gene (mOAT) encoding ornithine aminotransferase. A comparison of these mOAT sequences with previously reported sequences for the rat and human genes encoding OAT, rOAT and hOAT, respectively, revealed a 256-bp region flanking the transcription start point that is highly conserved between the three genes. This region contains sequence motifs resembling binding sites for general transcription factors, as well as other trans-acting regulatory proteins.
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Affiliation(s)
- J D Shull
- Eppley Institute for Research in Cancer and Allied Diseases, University of Nebraska Medical Center, Omaha 68198-6805, USA
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36
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Toyoda Y, Miwa I, Kamiya M, Ogiso S, Nonogaki T, Aoki S, Okuda J. Tissue and subcellular distribution of glucokinase in rat liver and their changes during fasting-refeeding. Histochem Cell Biol 1995; 103:31-8. [PMID: 7736279 DOI: 10.1007/bf01464473] [Citation(s) in RCA: 21] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
The distribution of glucokinase in rat liver under both normal feeding and fasting-refeeding conditions was investigated immunohistochemically. Under normal feeding conditions, glucokinase immunoreactivity was observed in both nuclei and cytoplasm of parenchymal cells. The nuclei were stained intensely and evenly, whereas the cytoplasm showed weak immunoreactivity of different degrees of staining intensity depending on the location of the cells. The cytoplasm of perivenous hepatocytes was stained more intensely, though not so much more, than that of periportal hepatocytes. The cytoplasm of hepatocytes surrounding the terminal hepatic venule (THV), of hepatocytes surrounding the portal triad, and of some other hepatocytes showed a stronger immunoreactivity than that of residual hepatocytes. The nuclear immunoreactivity in hepatocytes surrounding the portal triad and in some other hepatocytes was weak or absent, and positive immunoreactivity was detected at the plasma membrane of some of these cells. After 72 h of fasting, glucokinase immunoreactivity was markedly decreased in all hepatocytes. After the start of refeeding, the cytoplasmic immunoreactivity began to increase first in the parenchymal cells surrounding the THV and extended to those in the intermediate zone followed by those in the periportal zone. In contrast, the increase in nuclear immunoreactivity started in hepatocytes situated in the intermediate zone adjacent to the perivenous zone and then extended to those in the perivenous zone followed by those in the periportal zone. Hepatocytes surrounding either THV or portal triad showed a distinctive change in immunoreactivity during the refeeding period. After 10 h of refeeding, strong immunoreactivity was observed in both the cytoplasm and the nuclei of all hepatocytes, and appreciable glucokinase immunoreactivity was detected at the plasma membrane of some hepatocytes. These findings are discussed from the standpoint of a functional role of glucokinase in hepatic glucose metabolism.
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Affiliation(s)
- Y Toyoda
- Department of Clinical Biochemistry, Faculty of Pharmacy, Meijo University, Nagoya, Japan
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37
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Colombatto S, Giribaldi G, Vargiu C, Grillo MA. Modulation of ornithine aminotransferase activity by oxygen in rat hepatocyte cultures. BIOCHIMICA ET BIOPHYSICA ACTA 1994; 1224:329-32. [PMID: 7803486 DOI: 10.1016/0167-4889(94)90264-x] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
In hepatocytes in culture, ornithine aminotransferase activity remained higher when the cells were cultured at low oxygen tension (5%) than at high tension (21%), that is, it was higher in hepatovenous conditions. Northern blot analysis showed that the amount of the specific mRNA for the enzyme was also higher. Results of experiments performed in the presence of CoCl2, to replace the central Fe2+ in heme, or succinylacetone, to inhibit heme synthesis, support the view that a heme protein participates in the regulation of ornithine aminotransferase activity by oxygen. The oxygen sensor does not appear to act through phosphorylation by kinase C, as TPA has no significant effect on the process, but a phosphorylation dependent on cAMP might be involved.
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Affiliation(s)
- S Colombatto
- Dipartimento di Medicina e Oncologia Sperimentale, Universita' di Torino, Italy
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38
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Gebhardt R, Reichen J. Changes in distribution and activity of glutamine synthetase in carbon tetrachloride-induced cirrhosis in the rat: potential role in hyperammonemia. Hepatology 1994. [PMID: 7915704 DOI: 10.1002/hep.1840200320] [Citation(s) in RCA: 39] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
Abstract
Cirrhosis induced in rats by carbon tetrachloride was used to study alterations in the activities and lobular distribution of carbamoylphosphate synthetase and glutamine synthetase. Specific activity of carbamoylphosphate synthetase in cirrhotic subjects was decreased to 70% of controls. Staining was homogeneous within micronodular areas, but varied from area to area and generally showed a decreased intensity. Specific activity of glutamine synthetase and the size of the glutamine synthetase-positive area were decreased to 20% and less of controls. Glutamine synthetase-positive hepatocytes were rare and scattered at the periphery of nodular areas and within fibrous septa, the normal association with the central veins being widely lost. Rarely, complete micronodules showed a slight homogeneous staining for glutamine synthetase. Arginase activity was not affected, whereas glutaminase activity was enhanced by 50%. Serum levels of ammonia were elevated more than 2-fold and those of glutamine by 30%. In contrast, urea levels tended to be slightly diminished. Serum ammonia levels showed a clear negative correlation with the specific activity of glutamine synthetase and the size of the glutamine synthetase-positive area. Furthermore, blood urea levels correlated with the sum of ammonia and glutamine concentrations, but not with each of these substrate concentrations alone. These data suggest that the changes in activity and distribution of glutamine synthetase contribute to hyperammonemia in cirrhosis. Despite a reduced activity of the initial enzyme of the urea cycle, urea synthesis is not diminished accordingly. This may be due to an enhanced flux caused by the elevated blood level of ammonia and an increased hydrolysis of glutamine, because of higher levels of glutaminase.
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Affiliation(s)
- R Gebhardt
- Physiologisch-chemisches Institut, University of Tübingen, Federal Republic of Germany
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Wagenaar GT, Moorman AF, Chamuleau RA, Deutz NE, De Gier C, De Boer PA, Verbeek FJ, Lamers WH. Vascular branching pattern and zonation of gene expression in the mammalian liver. A comparative study in rat, mouse, cynomolgus monkey, and pig. Anat Rec (Hoboken) 1994; 239:441-52. [PMID: 7978367 DOI: 10.1002/ar.1092390410] [Citation(s) in RCA: 20] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
BACKGROUND A significant part of the liver volume consists of regions in which hepatocytes are in close contact with large branches of the afferent (portal vein) or efferent (hepatic vein) vessels. As most studies have addressed zonation of gene expression around the parenchymal branches of the portal and hepatic vein only, the patterns of gene expression in hepatocytes surrounding larger vessels are largely unknown. METHODS For that reason, we studied the patterns of expression of the mRNAs and proteins of the pericentral marker enzymes glutamine synthase, ornithine aminotransferase, and glutamate dehydrogenase and the periportal marker enzymes phosphoenolpyruvate carboxykinase and carbamoylphosphate synthase in the rat liver, in relation to the branching pattern of the afferent and efferent hepatic veins with immuno and hybridocytochemical techniques. These patterns of expression were compared with those seen in mouse, monkey, and pig liver. RESULTS The distribution patterns of the genes studied appear to reflect the "intensity" of the pericentral and periportal environment, glutamine synthase and phosphoenolypyruvate carboxykinase requiring the most pronounced environment, respectively. The patterns of gene expression around the large branches of the portal and hepatic vein were found to be related to the parenchymal branches in the neighbourhood of these large blood vessels. Only the cells of the limiting plate retain their periportal and pericentral phenotype for those marker enzymes that do not require a pronounced periportal or pericentral environment to be expressed. GS-negative areas in the pericentral limiting plate appear to correlate with a local absence of draining central veins, and become more frequent and extensive around the larger branches of the hepatic vein. CONCLUSIONS The similarity of the observed patterns of gene expression of the genes studied in mouse, rat, monkey, pig, and man suggests that they reflect a general feature of gene expression in the mammalian liver. A comparison of mouse, rat, pig, and human liver suggests that the presence of glutamine synthase-negative areas reflects the branching order of the efferent hepatic blood vessel.
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Affiliation(s)
- G T Wagenaar
- Department of Anatomy and Embryology, University of Amsterdam, The Netherlands
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40
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Gupta S, Vemuru RP, Lee CD, Yerneni PR, Aragona E, Burk RD. Hepatocytes exhibit superior transgene expression after transplantation into liver and spleen compared with peritoneal cavity or dorsal fat pad: implications for hepatic gene therapy. Hum Gene Ther 1994; 5:959-67. [PMID: 7948145 DOI: 10.1089/hum.1994.5.8-959] [Citation(s) in RCA: 55] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023] Open
Abstract
For hepatic gene therapy or applications of hepatocyte transplantation in liver failure, survival and function of transplanted cells is critical. Insights into site-specific gene regulation will significantly facilitate development of appropriate strategies for transplanting hepatocytes. To assess the function of transplanted cells, we used a transgenic hepatitis B virus (HBV) hepatocyte system, which allowed analysis of cellular gene expression with HBV surface antigen (HBsAg) mRNA expression, as well as secretion of HBsAg into peripheral circulation. When congeneic HBV hepatocytes were transplanted into the liver (via spleen), serum HBsAg promptly appeared in circulation and persisted for the entire duration of the studies. In contrast, transplantation of hepatocytes into the peritoneal cavity or dorsal fat pad resulted in serum HBsAg levels that were either significantly lower or gradually rose after a lag period. HBsAg mRNA expression was several-fold greater in transplanted hepatocytes in liver or spleen versus in peritoneal cavity or dorsal fat pad. Despite persistence of transplanted hepatocytes in peritoneal cavity or dorsal fat pad, serum HBsAg was cleared by antibody to HBsAg (anti-HBs) but this was not observed after hepatocyte transplantation into spleen. As the function of transplanted hepatocytes is optimally regulated in the liver, hepatic reconstitution with cell transplantation will be most appropriate for gene therapy.
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Affiliation(s)
- S Gupta
- Department of Medicine, Marion Bessin Liver Research Center, Albert Einstein College of Medicine, Bronx, NY 10461
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41
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Christa L, Simon MT, Flinois JP, Gebhardt R, Brechot C, Lasserre C. Overexpression of glutamine synthetase in human primary liver cancer. Gastroenterology 1994; 106:1312-20. [PMID: 7909780 DOI: 10.1016/0016-5085(94)90024-8] [Citation(s) in RCA: 73] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
BACKGROUND/AIMS We have identified several clones specifically expressed during malignant cell proliferation by screening a complementary DNA library constructed from a human primary liver cancer with subtractive probes. One clone was identified as the glutamine synthetase (GS) transcript. Its expression is tightly regulated during development, especially in the hepatic lobule. Because this enzyme is involved in nitrogen homeostasis, it might contribute to tumor development/progression in primary liver cancer. METHODS We compared the expression of GS messenger RNA (mRNA) and protein in tumorous and nontumorous liver from 34 patients with primary liver cancers, using a combination of Northern blot, dot blot, western blot, and determination of GS enzyme activity. RESULTS GS mRNA was higher in tumors versus nontumors in 23 of 34 primary liver cancer samples. GS activity was higher in 6 of 8 selected primary liver cancer samples with high RNA levels. GS protein levels were proportional to enzyme activity. A major GS transcript of 2.8 kilobase was detected by Northern blotting and sequencing. This comprised the minor 1.8-kb transcript and a long 3' untranslated region; the latter contained an AT-rich zone, fully conserved in the chicken, mouse, and rat, which might be important for stability. CONCLUSIONS Our results show an overexpression of GS in human primary liver cancers and, thus, point to its potential involvement in hepatocyte transformation.
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Affiliation(s)
- L Christa
- Institut de la Santé et de la Recherche Médicale U370, CHU Necker, Paris, France
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42
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Bralet MP, Branchereau S, Brechot C, Ferry N. Cell lineage study in the liver using retroviral mediated gene transfer. Evidence against the streaming of hepatocytes in normal liver. THE AMERICAN JOURNAL OF PATHOLOGY 1994; 144:896-905. [PMID: 8178942 PMCID: PMC1887360] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
The fate of normal hepatocytes in adult rat liver was studied after genetic labeling using the Escherichia coli beta-galactosidase gene coupled to a nuclear localization signal. The marker gene was introduced by direct in vivo retroviral-mediated gene transfer into hepatocytes 24 hours after partial hepatectomy. Analysis of beta-galactosidase expression in the liver at various time after gene transfer revealed that labeled hepatocytes were distributed throughout the entire lobule with a predominance in the periportal and mediolobular regions. Long-term experiments demonstrated that division of hepatocytes did occur as was revealed by the increasing number of beta-galactosidase-positive cells in isolated clusters. There was no evidence for the participation of stem cells in this process. Moreover, we found that after more than 1 year, the pattern of distribution of positive cells within the lobule was not modified. This suggests that hepatocytes do not migrate from the portal space to the perivenous region, as has been previously hypothesized.
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Affiliation(s)
- M P Bralet
- INSERM U370, CHU Necker-Enfants Malades, Paris, France
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43
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Gebhardt R, Gaunitz F, Mecke D. Heterogeneous (positional) expression of hepatic glutamine synthetase: features, regulation and implications for hepatocarcinogenesis. ADVANCES IN ENZYME REGULATION 1994; 34:27-56. [PMID: 7942280 DOI: 10.1016/0065-2571(94)90007-8] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
Glutamine synthetase expression in liver parenchyma is restricted to a small population of pericentral hepatocytes surrounding the central veins. Studies on the development of this heterogeneous (positional) gene expression and of the changes observed in response to experimental alterations of liver physiology or manipulations of hepatocytes in culture have revealed that it is dependent on cell-cell and cell-matrix interactions rather than on the levels of hormones and other modulating factors. The considerable stability of GS expression may point to further events leading to a defined differentiated GS+ phenotype. Observations during experimental hepatocarcinogenesis indicate that strong GS expression may be used for tracing hepatocellular lineages during preneoplastic and early neoplastic stages. Furthermore, these studies suggest a relationship between the GS+ phenotype and enhanced growth of these lesions. Future studies should help to define the diagnostic value of GS and its significance for new chemotherapeutic strategies.
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Affiliation(s)
- R Gebhardt
- Physiologisch-chemisches Institut der Universität Tübingen, Germany
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44
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Bode BP. Novel control of the position-dependent expression of genes in hepatocytes: the Glut-1 transporter. JPEN J Parenter Enteral Nutr 1994; 18:83-4. [PMID: 8164312 DOI: 10.1177/014860719401800183] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Affiliation(s)
- B P Bode
- Division of Surgical Oncology, Massachusetts General Hospital, Boston
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45
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Affiliation(s)
- B M Bilir
- Division of Gastroenterology, University of Michigan Medical Center, Ann Arbor
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46
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Novel control of the position-dependent expression of genes in hepatocytes. The GLUT-1 transporter. J Biol Chem 1993. [DOI: 10.1016/s0021-9258(19)36581-0] [Citation(s) in RCA: 20] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
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Simon T, Roth K, Gordon J. Use of transgenic mice to map cis-acting elements in the liver fatty acid-binding protein gene (Fabpl) that regulate its cell lineage-specific, differentiation-dependent, and spatial patterns of expression in the gut epithelium and in the liver acinus. J Biol Chem 1993. [DOI: 10.1016/s0021-9258(17)46851-7] [Citation(s) in RCA: 59] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022] Open
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48
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Fahrner J, Labruyere WT, Gaunitz C, Moorman AF, Gebhardt R, Lamers WH. Identification and functional characterization of regulatory elements of the glutamine synthetase gene from rat liver. EUROPEAN JOURNAL OF BIOCHEMISTRY 1993; 213:1067-73. [PMID: 8099326 DOI: 10.1111/j.1432-1033.1993.tb17854.x] [Citation(s) in RCA: 55] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
Hepatic glutamine synthetase (GS) shows a unique expression pattern limited to a few hepatocytes surrounding the terminal hepatic veins. Starting from the genomic clone of the rat GS gene, lambda GS1 [Van de Zande, L. P. G. W., Labruyère, W. T., Arnberg, A. C., Wilson, R. H., Van den Bogaert, A. J. W., Das, A. T., Frijters, C., Charles, R., Moorman, A. F. M. & Lamers, W. H. (1990) Gene (Amst.) 87, 225-232] additional genomic clones containing up to 9 kb of 5'flanking region were isolated in order to characterize cis-acting elements involved in the regulation of GS expression. Sequence analysis of the 5'flanking region up to -2520 bp revealed a putative AP2-binding site at -223 bp and a second GC box at -2343 bp in addition to the canonical TATA, CCAAT and GC boxes found proximal to the transcription-start site. A possible negative glucocorticoid-responsive element (GRE) and regions with very weak similarity to a GRE and to a known silencer element were noted at -506 bp, -406 bp and at -798 bp, respectively. Within the sequenced part of the 5'flanking region no known regulatory elements associated with liver-specific gene expression were found except for a putative HNF3-binding site at -896 bp. Functional analysis by transient transfection assays using constructs with the pSSCAT or the pXP1 vector revealed that the elements present within the first 153 bp and particularly the first 368 bp of upstream sequence constitute an active promoter the activity of which is decreased by additional sequences up to -2148 bp. The presence of dexamethasone led to a 2-4-fold increase in the promoter activity of all these constructs. Using the heterologous truncated thymidine-kinase-gene promoter of the plasmid pT81-luc a strong enhancer element was located between -2520 bp and -2148 bp. Its activity was not affected by dexamethasone but was negatively influenced by flanking sequences in both directions. This enhancer was also effective with the homologous GS promoter (-153 to +59 bp) and the heterologous full thymidine-kinase-gene promoter (pT109luc). No further enhancers were found up to -6200 bp. Using the same approach, a second enhancer was found between +259 bp and +950 bp within the first intron. Deoxyribonuclease-I hypersensitivity studies confirmed the presence of a hypersensitive site between +350 bp and +550 bp and suggested a second site between +850 bp and +1200 bp.(ABSTRACT TRUNCATED AT 400 WORDS)
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Affiliation(s)
- J Fahrner
- Physiologisch-chemisches Institut, Universität Tübingen, Germany
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49
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Emerson JA, Vacher J, Cirillo LA, Tilghman SM, Tyner AL. The zonal expression of alpha-fetoprotein transgenes in the livers of adult mice. Dev Dyn 1992; 195:55-66. [PMID: 1284040 DOI: 10.1002/aja.1001950106] [Citation(s) in RCA: 20] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022] Open
Abstract
The developmental regulation of the alpha-fetoprotein (AFP) gene in liver results in high-level expression in the fetus, followed by dramatic transcriptional repression after birth. We have examined the mouse AFP gene for transcriptional control sequences that may be involved in its postnatal repression in liver. We showed previously that removal of a DNA region between positions -250 base pairs (bp) and -838 bp of the AFP gene resulted in the persistence of expression of an AFP minigene in the postpartum liver of transgenic mice (Vacher and Tilghman, Science 250:1732-1735, 1990). This study examines the distribution of these transgene transcripts in liver using in situ hybridization. We show that there is a zonal distribution of minigene transcripts in the adult livers of these animals. Hepatocytes surrounding the central veins express high levels of minigene transcripts, while hepatocytes in the intermediate and portal areas contain few, if any, transcripts. Quantitative RNAse protection analysis shows a decrease in transgene RNA levels after birth, consistent with repression in all but a small subset of hepatocytes. These results indicate that repression in the pericentral hepatocytes is dependent upon the presence of a cis-acting, negative-regulatory domain, which is located between the enhancers and the proximal promoter of the AFP gene. In contrast, this domain is not essential for complete repression of AFP transgenes in the intermediate zone and periportal hepatocytes.
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Affiliation(s)
- J A Emerson
- Howard Hughes Medical Institute, Princeton University, New Jersey
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50
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Palmer CN, Coates PJ, Davies SE, Shephard EA, Phillips IR. Localization of cytochrome P-450 gene expression in normal and diseased human liver by in situ hybridization of wax-embedded archival material. Hepatology 1992; 16:682-7. [PMID: 1505911 DOI: 10.1002/hep.1840160311] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
The localization of the expression of several cytochrome P-450 genes in normal and diseased human liver was investigated by in situ hybridization of formalin-fixed, paraffin wax-embedded archival tissue samples with 35S-labeled antisense RNA probes. The results demonstrated that genes coding for members of the cytochrome P-450 3A subfamily (CYP3A) were preferentially expressed in hepatocytes in acinar zone 3 (the centrilobular region), whereas genes coding for CYP1A2, CYP2A, 2B and 2C were expressed uniformly throughout the liver acinus. In cirrhotic livers, CYP2A and 2B genes (and to a lesser extent, CYP3A genes) were highly expressed in isolated hepatocytes located at the junction of parenchyma with fibrous septa. The cause and significance of the position-dependent expression of specific cytochrome P-450 genes in normal and diseased human liver are discussed.
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Affiliation(s)
- C N Palmer
- Department of Biochemistry, Queen Mary and Westfield College, University of London, United Kingdom
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