1
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Mantilla Rojas C, McGill MP, Salvador AC, Bautz D, Threadgill DW. Epithelial-specific ERBB3 deletion results in a genetic background-dependent increase in intestinal and colon polyps that is mediated by EGFR. PLoS Genet 2021; 17:e1009931. [PMID: 34843459 PMCID: PMC8659709 DOI: 10.1371/journal.pgen.1009931] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2021] [Revised: 12/09/2021] [Accepted: 11/05/2021] [Indexed: 11/18/2022] Open
Abstract
ERBB3 has gained attention as a potential therapeutic target to treat colorectal and other types of cancers. To confirm a previous study showing intestinal polyps are dependent upon ERBB3, we generated an intestinal epithelia-specific ERBB3 deletion in C57BL/6-ApcMin/+ mice. Contrary to the previous report showing a significant reduction in intestinal polyps with ablation of ERBB3 on a B6;129 mixed genetic background, we observed a significant increase in polyp number with ablation of ERBB3 on C57BL/6J compared to control littermates. We confirmed the genetic background dependency of ERBB3 by also analyzing polyp development on B6129 hybrid and B6;129 advanced intercross mixed genetic backgrounds, which showed that ERBB3 deficiency only reduced polyp number on the mixed background as previously reported. Increased polyp number with ablation of ERBB3 was also observed in C57BL/6J mice treated with azoxymethane showing the effect is model independent. Polyps forming in absence of ERBB3 were generally smaller than those forming in control mice, albeit the effect was greatest in genetic backgrounds with reduced polyp numbers. The mechanism for differential polyp number in the absence of ERBB3 was through altered proliferation. Backgrounds with increased polyp number with loss of ERBB3 showed an increase in cell proliferation even in non-tumor epithelia, while backgrounds showing reduced polyp number with loss of ERBB3 showed reduced cellular proliferation. Increase polyp number caused by loss of ERBB3 was mediated by increased epidermal growth factor receptor (EGFR) expression, which was confirmed by deletion of Egfr. Taken together, this study raises substantial implications on the use of ERBB3 inhibitors against colorectal cancer. The prediction is that some patients may have increased progression with ERBB3 inhibitor therapy, which is consistent with observations reported for ERBB3 inhibitor clinical trials.
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Affiliation(s)
- Carolina Mantilla Rojas
- Interdisciplinary Program in Genetics, Texas A&M University, College Station, Texas, United States of America.,Department of Molecular and Cellular Medicine, Texas A&M University, College Station, Texas, United States of America
| | - Michael P McGill
- Interdisciplinary Program in Genetics, Texas A&M University, College Station, Texas, United States of America.,Department of Molecular and Cellular Medicine, Texas A&M University, College Station, Texas, United States of America
| | - Anna C Salvador
- Interdisciplinary Program in Genetics, Texas A&M University, College Station, Texas, United States of America.,Department of Nutrition, Texas A&M University, College Station, Texas, United States of America
| | - David Bautz
- Department of Genetics, North Carolina State University, Raleigh, North Carolina, United States of America
| | - David W Threadgill
- Interdisciplinary Program in Genetics, Texas A&M University, College Station, Texas, United States of America.,Department of Molecular and Cellular Medicine, Texas A&M University, College Station, Texas, United States of America.,Department of Nutrition, Texas A&M University, College Station, Texas, United States of America.,Department of Biochemistry & Biophysics and Department of Nutrition, Texas A&M University, College Station, Texas, United States of America
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2
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Siebert AE, Maroney SA, Martinez ND, Mast AE. Intrauterine lethality in Tfpi gene disrupted mice is differentially suppressed during mid- and late-gestation by platelet TFPIα overexpression. J Thromb Haemost 2021; 19:1483-1492. [PMID: 33728763 PMCID: PMC8165032 DOI: 10.1111/jth.15299] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2020] [Revised: 02/05/2021] [Accepted: 03/02/2021] [Indexed: 01/16/2023]
Abstract
BACKGROUND Tissue factor pathway inhibitor (TFPI) is an anticoagulant protein required for murine embryonic development. Intrauterine lethality of Tfpi-/- mice occurs at mid- and late gestation, the latter of which is associated with severe cerebrovascular defects. Megakaryocytes produce only the TFPIα isoform, which is stored within platelets and released upon activation. OBJECTIVES To examine biological activities of platelet TFPIα (pTFPIα) by characterizing effects of pTFPIα overexpression in Tfpi-/- mice. METHODS Transgenic mice overexpressing pTFPIα were generated and crossed onto the Tfpi-/- background. Genetic and histological analyses of embryos were performed to investigate the function of pTFPIα during embryogenesis. RESULTS The transgene (Tg) increased pTFPIα 4- to 5-fold without altering plasma TFPI in adult Tfpi+/+ and Tfpi+/- mice but did not rescue Tfpi-/- mice to wean. Analyses of the impact of pTFPIα overexpression on Tfpi-/- survival, however, were complicated by linkage between the Tg integration site and the endogenous Tfpi locus on chromosome 2. Strain-specific genetic interactions also modulated Tfpi-/- embryonic survival. After accounting for these underlying genetic factors, pTFPIα overexpression completely suppressed mid-gestational lethality of Tfpi-/- embryos but had no effect on development of cerebrovascular defects during late gestation resulting in their lack of survival to wean. CONCLUSIONS pTFPIα overexpression rescued Tfpi-/- embryos from mid-gestational but not late gestational lethality. The prevalence of underlying genetic factors complicating analyses within our study illustrates the importance of meticulously characterizing transgenic mouse models to avoid spurious interpretation of results.
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Affiliation(s)
| | | | | | - Alan E. Mast
- Versiti Blood Research Institute, Milwaukee, WI, USA
- Department of Cell Biology, Neurobiology and Anatomy, Medical College of Wisconsin, Milwaukee, WI, USA
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3
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Marsh B, Blelloch R. Single nuclei RNA-seq of mouse placental labyrinth development. eLife 2020; 9:e60266. [PMID: 33141023 PMCID: PMC7669270 DOI: 10.7554/elife.60266] [Citation(s) in RCA: 76] [Impact Index Per Article: 19.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2020] [Accepted: 10/30/2020] [Indexed: 12/21/2022] Open
Abstract
The placenta is the interface between mother and fetus in all eutherian species. However, our understanding of this essential organ remains incomplete. A substantial challenge has been the syncytial cells of the placenta, which have made dissociation and independent evaluation of the different cell types of this organ difficult. Here, we address questions concerning the ontogeny, specification, and function of the cell types of a representative hemochorial placenta by performing single nuclei RNA sequencing (snRNA-seq) at multiple stages of mouse embryonic development focusing on the exchange interface, the labyrinth. Timepoints extended from progenitor-driven expansion through terminal differentiation. Analysis by snRNA-seq identified transcript profiles and inferred functions, cell trajectories, signaling interactions, and transcriptional drivers of all but the most highly polyploid cell types of the placenta. These data profile placental development at an unprecedented resolution, provide insights into differentiation and function across time, and provide a resource for future study.
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Affiliation(s)
- Bryan Marsh
- The Eli and Edythe Broad Center of Regeneration Medicine and Stem Cell Research, Center for Reproductive Sciences, University of California, San FranciscoSan FranciscoUnited States
- Department of Urology, University of California, San FranciscoSan FranciscoUnited States
| | - Robert Blelloch
- The Eli and Edythe Broad Center of Regeneration Medicine and Stem Cell Research, Center for Reproductive Sciences, University of California, San FranciscoSan FranciscoUnited States
- Department of Urology, University of California, San FranciscoSan FranciscoUnited States
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4
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Liu Z, Skafar DF, Kilburn B, Das SK, Armant DR. Extraembryonic heparin-binding epidermal growth factor-like growth factor deficiency compromises placentation in mice. Biol Reprod 2020; 100:217-226. [PMID: 30084919 DOI: 10.1093/biolre/ioy174] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2016] [Accepted: 07/27/2018] [Indexed: 01/04/2023] Open
Abstract
Heparin-binding epidermal growth factor (EGF)-like growth factor (HBEGF) is expressed in the embryo and uterus at the implantation site, stimulating trophoblast invasive activity essential for placentation. The effect of extraembryonic HBEGF deficiency on placental development was investigated by breeding mice heterozygous for the Hbegf null mutation. On gestation day 13.5, the average placental weights of the wild-type (Hbegf+/+) and heterozygous (Hbegf+/-) mice were approximately 76 and 77 mg, respectively, as opposed to reduced average placental weights of approximately 61 mg in homozygous null (Hbgef-/-) females. In contrast, fetal weights were not significantly affected by genotype. HBEGF immunostaining in placental sections was Hbegf gene dosage-dependent, while expression of other EGF family members was comparable in Hbegf+/+ and Hbegf-/- placentas. Histological analysis revealed no apparent differences in trophoblast giant cells, but the spongiotrophoblast region was reduced compared to labyrinth (P < 0.05) in Hbegf null placentas. While no differences in cell apoptosis were noted, proliferation as assessed by nuclear Ki67 staining was elevated in the labyrinth and decreased in the spongiotrophoblast region of Hbegf-/- placentas. Labyrinth morphology appeared disrupted in Hbegf -/- placentas stained with laminin, a marker for capillary basement membrane, and the capillary density was reduced. Immunohistochemical staining revealed reduced vascular endothelial growth factor (VEGF) levels in both spongiotrophoblast and labyrinth (P < 0.01) regions of Hbegf-/- placentas. In vitro, HBEGF supplementation increases the expression of VEGF in a human trophoblast cell line. These findings suggest that trophoblast HBEGF promotes placental capillary formation by inducing VEGF in the developing placenta of mice.
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Affiliation(s)
- Zitao Liu
- Department of Pediatrics, Division of Reproductive and Developmental Biology, Vanderbilt University Medical Center, Nashville, Tennessee, USA.,New Hope Fertility Center, New York City, New York, USA
| | - Debra F Skafar
- Department of Physiology, Wayne State University School of Medicine, Detroit, Michigan, USA
| | - Brian Kilburn
- Departments of Obstetrics & Gynecology and Anatomy and Cell Biology, Wayne State University, Detroit, Michigan, USA
| | - Sanjoy K Das
- Department of Pediatrics, Division of Reproductive and Developmental Biology, Vanderbilt University Medical Center, Nashville, Tennessee, USA.,Cincinnati Children's Hospital Medical Center, Cincinnati, Ohio, USA
| | - D Randall Armant
- Departments of Obstetrics & Gynecology and Anatomy and Cell Biology, Wayne State University, Detroit, Michigan, USA
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5
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Foroughi S, Tie J, Gibbs P, Burgess AW. Epidermal growth factor receptor ligands: targets for optimizing treatment of metastatic colorectal cancer. Growth Factors 2019; 37:209-225. [PMID: 31878812 DOI: 10.1080/08977194.2019.1703702] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/17/2023]
Abstract
The discovery of epidermal growth factor (EGF) and its receptor (EGFR) revealed the connection between EGF-like ligands, signaling from the EGFR family members and cancer. Over the next fifty years, analysis of EGFR expression and mutation led to the use of monoclonal antibodies to target EGFR in the treatment of metastatic colorectal cancer (mCRC) and this treatment has improved outcomes for patients. The use of the RAS oncogene mutational status has helped to refine patient selection for EGFR antibody therapy, but an effective molecular predictor of likely responders is lacking. This review analyzes the potential utility of measuring the expression, levels and activation of EGF-like ligands and associated processes as prognostic or predictive markers for the identification of patient risk and more effective mCRC therapies.
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Affiliation(s)
- Siavash Foroughi
- Personalised Oncology Division, The Walter and Eliza Hall Institute of Medical Research, Parkville, Australia
- Department of Medical Biology, The University of Melbourne, Parkville, Australia
| | - Jeanne Tie
- Personalised Oncology Division, The Walter and Eliza Hall Institute of Medical Research, Parkville, Australia
- Department of Medical Biology, The University of Melbourne, Parkville, Australia
- Department of Medical Oncology, Peter MacCallum Cancer Centre, Melbourne, Australia
- Department of Medical Oncology, Western Health, St Albans, Australia
| | - Peter Gibbs
- Personalised Oncology Division, The Walter and Eliza Hall Institute of Medical Research, Parkville, Australia
- Department of Medical Biology, The University of Melbourne, Parkville, Australia
- Department of Medical Oncology, Western Health, St Albans, Australia
| | - Antony Wilks Burgess
- Personalised Oncology Division, The Walter and Eliza Hall Institute of Medical Research, Parkville, Australia
- Department of Medical Biology, The University of Melbourne, Parkville, Australia
- Department of Surgery, Royal Melbourne Hospital, The University of Melbourne, Parkville, Australia
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6
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Sorgini CA, Barrios-Perez I, Brown PJ, Ainsworth EA. Examining Genetic Variation in Maize Inbreds and Mapping Oxidative Stress Response QTL in B73-Mo17 Nearly Isogenic Lines. FRONTIERS IN SUSTAINABLE FOOD SYSTEMS 2019. [DOI: 10.3389/fsufs.2019.00051] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022] Open
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7
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Eggenschwiler R, Patronov A, Hegermann J, Fráguas-Eggenschwiler M, Wu G, Cortnumme L, Ochs M, Antes I, Cantz T. A combined in silico and in vitro study on mouse Serpina1a antitrypsin-deficiency mutants. Sci Rep 2019; 9:7486. [PMID: 31097772 PMCID: PMC6522476 DOI: 10.1038/s41598-019-44043-3] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2018] [Accepted: 05/07/2019] [Indexed: 01/15/2023] Open
Abstract
Certain point-mutations in the human SERPINA1-gene can cause severe α1-antitrypsin-deficiency (A1AT-D). Affected individuals can suffer from loss-of-function lung-disease and from gain-of-function liver-disease phenotypes. However, age of onset and severity of clinical appearance is heterogeneous amongst carriers, suggesting involvement of additional genetic and environmental factors. The generation of authentic A1AT-D mouse-models has been hampered by the complexity of the mouse Serpina1-gene locus and a model with concurrent lung and liver-disease is still missing. Here, we investigate point-mutations in the mouse Serpina1a antitrypsin-orthologue, which are homolog-equivalent to ones known to cause severe A1AT-D in human. We combine in silico and in vitro methods and we find that analyzed mutations do introduce potential disease-causing properties into Serpina1a. Finally, we show that introduction of the King’s-mutation causes inactivation of neutrophil elastase inhibitory-function in both, mouse and human antitrypsin, while the mouse Z-mutant retains activity. This work paves the path to generation of better A1AT-D mouse-models.
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Affiliation(s)
- Reto Eggenschwiler
- Research Group Translational Hepatology and Stem Cell Biology, Cluster of Excellence REBIRTH, Hannover Medical School, Hannover, 30625, Germany. .,Department of Gastroenterology, Hepatology and Endocrinology, Hannover Medical School, Hannover, 30625, Germany.
| | - Atanas Patronov
- Protein Modelling Group, Department of Life Sciences, Technical University Munich, Freising, 85354, Germany.,TUM School of Life Sciences, Center for Integrated Protein Science (CIPSM), Technical University Munich, Freising, 85354, Germany
| | - Jan Hegermann
- Research Core Unit Electron Microscopy, Hannover Medical School, Hannover, 30625, Germany.,Institute of Functional and Applied Anatomy, Hannover Medical School, Hannover, 30625, Germany.,Imaging Platform of the Cluster of Excellence REBIRTH, Hannover Medical School, Hannover, 30625, Germany
| | - Mariane Fráguas-Eggenschwiler
- Department of Gastroenterology, Hepatology and Endocrinology, Hannover Medical School, Hannover, 30625, Germany.,TWINCORE, Centre for Experimental and Clinical Infection Research, Hannover, 30625, Germany
| | - Guangming Wu
- Max Planck Institute for Molecular Biomedicine, Cell and Developmental Biology, Münster, 48149, Germany
| | - Leon Cortnumme
- Research Group Translational Hepatology and Stem Cell Biology, Cluster of Excellence REBIRTH, Hannover Medical School, Hannover, 30625, Germany.,Department of Gastroenterology, Hepatology and Endocrinology, Hannover Medical School, Hannover, 30625, Germany
| | - Matthias Ochs
- Research Core Unit Electron Microscopy, Hannover Medical School, Hannover, 30625, Germany.,Institute of Functional and Applied Anatomy, Hannover Medical School, Hannover, 30625, Germany.,Imaging Platform of the Cluster of Excellence REBIRTH, Hannover Medical School, Hannover, 30625, Germany.,Institute of Vegetative Anatomy Charité - Universitaetsmedizin Berlin, Berlin, 10115, Germany
| | - Iris Antes
- Protein Modelling Group, Department of Life Sciences, Technical University Munich, Freising, 85354, Germany.,TUM School of Life Sciences, Center for Integrated Protein Science (CIPSM), Technical University Munich, Freising, 85354, Germany
| | - Tobias Cantz
- Research Group Translational Hepatology and Stem Cell Biology, Cluster of Excellence REBIRTH, Hannover Medical School, Hannover, 30625, Germany. .,Department of Gastroenterology, Hepatology and Endocrinology, Hannover Medical School, Hannover, 30625, Germany. .,Max Planck Institute for Molecular Biomedicine, Cell and Developmental Biology, Münster, 48149, Germany.
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8
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Yang YP, Ma H, Starchenko A, Huh WJ, Li W, Hickman FE, Zhang Q, Franklin JL, Mortlock DP, Fuhrmann S, Carter BD, Ihrie RA, Coffey RJ. A Chimeric Egfr Protein Reporter Mouse Reveals Egfr Localization and Trafficking In Vivo. Cell Rep 2017; 19:1257-1267. [PMID: 28494873 PMCID: PMC5517093 DOI: 10.1016/j.celrep.2017.04.048] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2016] [Revised: 03/31/2017] [Accepted: 04/17/2017] [Indexed: 01/06/2023] Open
Abstract
EGF receptor (EGFR) is a critical signaling node throughout life. However, it has not been possible to directly visualize endogenous Egfr in mice. Using CRISPR/Cas9 genome editing, we appended a fluorescent reporter to the C terminus of the Egfr. Homozygous reporter mice appear normal and EGFR signaling is intact in vitro and in vivo. We detect distinct patterns of Egfr expression in progenitor and differentiated compartments in embryonic and adult mice. Systemic delivery of EGF or amphiregulin results in markedly different patterns of Egfr internalization and trafficking in hepatocytes. In the normal intestine, Egfr localizes to the crypt rather than villus compartment, expression is higher in adjacent epithelium than in intestinal tumors, and following colonic injury expression appears in distinct cell populations in the stroma. This reporter, under control of its endogenous regulatory elements, enables in vivo monitoring of the dynamics of Egfr localization and trafficking in normal and disease states.
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Affiliation(s)
- Yu-Ping Yang
- Department of Medicine, Vanderbilt University Medical Center, Nashville, TN 37232, USA; Epithelial Biology Center, Vanderbilt University Medical Center, Nashville, TN 37232, USA
| | - Haiting Ma
- Department of Medicine, Vanderbilt University Medical Center, Nashville, TN 37232, USA; Epithelial Biology Center, Vanderbilt University Medical Center, Nashville, TN 37232, USA
| | - Alina Starchenko
- Epithelial Biology Center, Vanderbilt University Medical Center, Nashville, TN 37232, USA; Department of Cell and Developmental Biology, Vanderbilt University, Nashville, TN 37232, USA
| | - Won Jae Huh
- Epithelial Biology Center, Vanderbilt University Medical Center, Nashville, TN 37232, USA; Department of Pathology, Microbiology and Immunology, Vanderbilt University Medical Center, Nashville, TN 37232, USA
| | - Wei Li
- Department of Medicine, Vanderbilt University Medical Center, Nashville, TN 37232, USA; Epithelial Biology Center, Vanderbilt University Medical Center, Nashville, TN 37232, USA
| | - F Edward Hickman
- Department of Biochemistry, Vanderbilt University, Nashville, TN 37232, USA
| | - Qin Zhang
- Department of Medicine, Vanderbilt University Medical Center, Nashville, TN 37232, USA; Epithelial Biology Center, Vanderbilt University Medical Center, Nashville, TN 37232, USA
| | - Jeffrey L Franklin
- Department of Medicine, Vanderbilt University Medical Center, Nashville, TN 37232, USA; Epithelial Biology Center, Vanderbilt University Medical Center, Nashville, TN 37232, USA; Department of Cell and Developmental Biology, Vanderbilt University, Nashville, TN 37232, USA; Department of Veterans Affairs Medical Center, Nashville, TN 37232, USA
| | - Douglas P Mortlock
- Department of Molecular Physiology and Biophysics, Vanderbilt University, Nashville, TN 37232, USA
| | - Sabine Fuhrmann
- Department of Cell and Developmental Biology, Vanderbilt University, Nashville, TN 37232, USA; Department of Ophthalmology and Visual Sciences, Vanderbilt University Medical Center, Nashville, TN 37232, USA
| | - Bruce D Carter
- Department of Biochemistry, Vanderbilt University, Nashville, TN 37232, USA
| | - Rebecca A Ihrie
- Department of Cell and Developmental Biology, Vanderbilt University, Nashville, TN 37232, USA; Department of Cancer Biology, Vanderbilt University, Nashville, TN 37232, USA; Department of Neurological Surgery, Vanderbilt University Medical Center, Nashville, TN 37232, USA
| | - Robert J Coffey
- Department of Medicine, Vanderbilt University Medical Center, Nashville, TN 37232, USA; Epithelial Biology Center, Vanderbilt University Medical Center, Nashville, TN 37232, USA; Department of Cell and Developmental Biology, Vanderbilt University, Nashville, TN 37232, USA; Department of Veterans Affairs Medical Center, Nashville, TN 37232, USA.
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9
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Reilly KM. The Effects of Genetic Background of Mouse Models of Cancer: Friend or Foe? Cold Spring Harb Protoc 2016; 2016:pdb.top076273. [PMID: 26933251 DOI: 10.1101/pdb.top076273] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Over the past century, mice have been selectively bred to give rise to the strains used in biomedical research today. Mouse models of cancer allow researchers to control variables of diet, environment, and genetic heterogeneity to better dissect the role of these factors in cancer in humans. Because of the important role of genetic background in cancer, the strain of the mouse can introduce confounding results in studies of mouse models if not properly controlled. Conversely, genetic variation between strains can also provide important new insights into cancer mechanisms. Here, the sources of genetic heterogeneity in mouse models are reviewed, with an explanation of how heterogeneity modifies cancer phenotypes.
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Affiliation(s)
- Karlyne M Reilly
- Mouse Cancer Genetics Program, National Cancer Institute, Frederick, Maryland 21702
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10
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Abstract
A disintegrin and metalloproteinases (ADAMs) are a family of cell surface proteases that regulate diverse cellular functions, including cell adhesion, migration, cellular signaling, and proteolysis. Proteolytically active ADAMs are responsible for ectodomain shedding of membrane-associated proteins. ADAMs rapidly modulate key cell signaling pathways in response to changes in the extracellular environment (e.g., inflammation) and play a central role in coordinating intercellular communication within the local microenvironment. ADAM10 and ADAM17 are the most studied members of the ADAM family in the gastrointestinal tract. ADAMs regulate many cellular processes associated with intestinal development, cell fate specification, and the maintenance of intestinal stem cell/progenitor populations. Several signaling pathway molecules that undergo ectodomain shedding by ADAMs [e.g., ligands and receptors from epidermal growth factor receptor (EGFR)/ErbB and tumor necrosis factor α (TNFα) receptor (TNFR) families] help drive and control intestinal inflammation and injury/repair responses. Dysregulation of these processes through aberrant ADAM expression or sustained ADAM activity is linked to chronic inflammation, inflammation-associated cancer, and tumorigenesis.
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Affiliation(s)
- Jennifer C Jones
- Cell Biology, Stem Cells, and Development Program and.,Division of Gastroenterology, Hepatology, and Nutrition and Department of Pediatrics, University of Colorado Medical School, Aurora, Colorado 80045; , ,
| | - Shelly Rustagi
- Division of Gastroenterology, Hepatology, and Nutrition and Department of Pediatrics, University of Colorado Medical School, Aurora, Colorado 80045; , ,
| | - Peter J Dempsey
- Cell Biology, Stem Cells, and Development Program and.,Division of Gastroenterology, Hepatology, and Nutrition and Department of Pediatrics, University of Colorado Medical School, Aurora, Colorado 80045; , ,
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11
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Scheving LA, Zhang X, Stevenson MC, Threadgill DW, Russell WE. Loss of hepatocyte EGFR has no effect alone but exacerbates carbon tetrachloride-induced liver injury and impairs regeneration in hepatocyte Met-deficient mice. Am J Physiol Gastrointest Liver Physiol 2015; 308:G364-77. [PMID: 25414100 PMCID: PMC4346751 DOI: 10.1152/ajpgi.00364.2014] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
The role(s) of the epidermal growth factor receptor (EGFR) in hepatocytes is unknown. We generated a murine hepatocyte specific-EGFR knockout (KO) model to evaluate how loss of hepatocellular EGFR expression affects processes such as EGF clearance, circulating EGF concentrations, and liver regeneration following 70% resection or CCl4-induced centrilobular injury. We were able to disrupt EGFR expression effectively in hepatocytes and showed that the ability of EGF and heregulin (HRG) to phosphorylate EGFR and ERBB3, respectively, required EGFR. Loss of hepatocellular EGFR impaired clearance of exogenous EGF from the portal circulation but paradoxically resulted in reduced circulating levels of endogenous EGF. This was associated with decreased submandibular salivary gland production of EGF. EGFR disruption did not result in increased expression of other ERBB proteins or Met, except in neonatal mice. Liver regeneration following 70% hepatectomy revealed a mild phenotype, with no change in cyclin D1 expression and slight differences in cyclin A expression compared with controls. Peak 5-bromo-2'-deoxyuridine labeling was shifted from 36 to 48 h. Centrilobular damage and regenerative response induced by carbon tetrachloride (CCl4) were identical in the KO and wild-type mice. In contrast, loss of Met increased CCl4-induced necrosis and delayed regeneration. Although loss of hepatocellular EGFR alone did not have an effect in this model, EGFR-Met double KOs displayed enhanced necrosis and delayed liver regeneration compared with Met KOs alone. This suggests that EGFR and Met may partially compensate for the loss of the other, although other compensatory mechanisms can be envisioned.
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Affiliation(s)
- Lawrence A. Scheving
- 1Department of Pediatrics, Vanderbilt University Medical Center, Nashville, Tennessee; ,3Digestive Disease Research Center, Vanderbilt University Medical Center, Nashville, Tennessee;
| | - Xiuqi Zhang
- 1Department of Pediatrics, Vanderbilt University Medical Center, Nashville, Tennessee;
| | - Mary C. Stevenson
- 1Department of Pediatrics, Vanderbilt University Medical Center, Nashville, Tennessee;
| | - David W. Threadgill
- 6Department of Veterinary Pathobiology, Texas A&M University, College Station, Texas; and ,7Department of Molecular and Cellular Medicine, Texas A&M University, College Station, Texas
| | - William E. Russell
- 1Department of Pediatrics, Vanderbilt University Medical Center, Nashville, Tennessee; ,2Department of Cell and Developmental Biology, Vanderbilt University Medical Center, Nashville, Tennessee; ,3Digestive Disease Research Center, Vanderbilt University Medical Center, Nashville, Tennessee; ,4Vanderbilt Diabetes Center, Vanderbilt University Medical Center, Nashville, Tennessee; ,5Vanderbilt Ingram Cancer Center, Vanderbilt University Medical Center, Nashville, Tennessee;
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12
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Tsang KH, Lai SK, Li Q, Yung WH, Liu H, Mak PHS, Ng CCP, McAlonan G, Chan YS, Chan SY. The nucleosome assembly protein TSPYL2 regulates the expression of NMDA receptor subunits GluN2A and GluN2B. Sci Rep 2014; 4:3654. [PMID: 24413569 PMCID: PMC3888966 DOI: 10.1038/srep03654] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2013] [Accepted: 12/16/2013] [Indexed: 12/31/2022] Open
Abstract
TSPYL2 is an X-linked gene encoding a nucleosome assembly protein. TSPYL2 interacts with calmodulin-associated serine/threonine kinase, which is implicated in X-linked mental retardation. As nucleosome assembly and chromatin remodeling are important in transcriptional regulation and neuronal function, we addressed the importance of TSPYL2 through analyzing Tspyl2 loss-of-function mice. We detected down-regulation of N-methyl-D-aspartate receptor subunits 2A and 2B (GluN2A and GluN2B) in the mutant hippocampus. Evidence from luciferase reporter assays and chromatin immunoprecipitation supported that TSPYL2 regulated the expression of Grin2a and Grin2b, the genes encoding GluN2A and GluN2B. We also detected an interaction between TSPYL2 and CBP, indicating that TSPYL2 may activate gene expression through binding CBP. In terms of functional outcome, Tspyl2 loss-of-function impaired long-term potentiation at hippocampal Schaffer collateral-CA1 synapses. Moreover, mutant mice showed a deficit in fear learning and memory. We conclude that TSPYL2 contributes to cognitive variability through regulating the expression of Grin2a and Grin2b.
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Affiliation(s)
- Ka Hing Tsang
- 1] Department of Paediatrics and Adolescent Medicine, Li Ka Shing Faculty of Medicine, the University of Hong Kong, Hong Kong, China [2] Centre for Reproduction, Development and Growth, Li Ka Shing Faculty of Medicine, the University of Hong Kong, Hong Kong, China
| | - Suk King Lai
- 1] Department of Physiology, Li Ka Shing Faculty of Medicine, the University of Hong Kong, Hong Kong, China [2] Research Centre of Heart, Brain, Hormone and Healthy Aging, Li Ka Shing Faculty of Medicine, the University of Hong Kong, Hong Kong, China
| | - Qi Li
- 1] Centre for Reproduction, Development and Growth, Li Ka Shing Faculty of Medicine, the University of Hong Kong, Hong Kong, China [2] Department of Psychiatry, Li Ka Shing Faculty of Medicine, the University of Hong Kong, Hong Kong, China
| | - Wing Ho Yung
- School of Biomedical Sciences, the Chinese University of Hong Kong, Hong Kong, China
| | - Hang Liu
- 1] Department of Paediatrics and Adolescent Medicine, Li Ka Shing Faculty of Medicine, the University of Hong Kong, Hong Kong, China [2] Centre for Reproduction, Development and Growth, Li Ka Shing Faculty of Medicine, the University of Hong Kong, Hong Kong, China
| | - Priscilla Hoi Shan Mak
- 1] Department of Paediatrics and Adolescent Medicine, Li Ka Shing Faculty of Medicine, the University of Hong Kong, Hong Kong, China [2] Centre for Reproduction, Development and Growth, Li Ka Shing Faculty of Medicine, the University of Hong Kong, Hong Kong, China
| | - Cypress Chun Pong Ng
- 1] Department of Paediatrics and Adolescent Medicine, Li Ka Shing Faculty of Medicine, the University of Hong Kong, Hong Kong, China [2] Centre for Reproduction, Development and Growth, Li Ka Shing Faculty of Medicine, the University of Hong Kong, Hong Kong, China
| | - Grainne McAlonan
- 1] Centre for Reproduction, Development and Growth, Li Ka Shing Faculty of Medicine, the University of Hong Kong, Hong Kong, China [2] Department of Psychiatry, Li Ka Shing Faculty of Medicine, the University of Hong Kong, Hong Kong, China [3] Department of Forensic and Neurodevelopmental Sciences, Institute of Psychiatry, King's College London, United Kingdom
| | - Ying Shing Chan
- 1] Department of Physiology, Li Ka Shing Faculty of Medicine, the University of Hong Kong, Hong Kong, China [2] Research Centre of Heart, Brain, Hormone and Healthy Aging, Li Ka Shing Faculty of Medicine, the University of Hong Kong, Hong Kong, China
| | - Siu Yuen Chan
- 1] Department of Paediatrics and Adolescent Medicine, Li Ka Shing Faculty of Medicine, the University of Hong Kong, Hong Kong, China [2] Centre for Reproduction, Development and Growth, Li Ka Shing Faculty of Medicine, the University of Hong Kong, Hong Kong, China
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13
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Does your gene need a background check? How genetic background impacts the analysis of mutations, genes, and evolution. Trends Genet 2013; 29:358-66. [PMID: 23453263 DOI: 10.1016/j.tig.2013.01.009] [Citation(s) in RCA: 117] [Impact Index Per Article: 10.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2012] [Revised: 01/09/2013] [Accepted: 01/25/2013] [Indexed: 11/23/2022]
Abstract
The premise of genetic analysis is that a causal link exists between phenotypic and allelic variation. However, it has long been documented that mutant phenotypes are not a simple result of a single DNA lesion, but are instead due to interactions of the focal allele with other genes and the environment. Although an experimentally rigorous approach focused on individual mutations and isogenic control strains has facilitated amazing progress within genetics and related fields, a glimpse back suggests that a vast complexity has been omitted from our current understanding of allelic effects. Armed with traditional genetic analyses and the foundational knowledge they have provided, we argue that the time and tools are ripe to return to the underexplored aspects of gene function and embrace the context-dependent nature of genetic effects. We assert that a broad understanding of genetic effects and the evolutionary dynamics of alleles requires identifying how mutational outcomes depend upon the 'wild type' genetic background. Furthermore, we discuss how best to exploit genetic background effects to broaden genetic research programs.
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14
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Abstract
Mouse models are indispensible tools for understanding the molecular basis of cancer. However, despite the invaluable data provided regarding tumour biology, owing to inbreeding, current mouse models fail to accurately model human populations. Polymorphism is the essential characteristic that makes each of us unique humans, with different disease susceptibility, presentation and progression. Therefore, as we move closer towards designing clinical treatment that is based on an individual's unique biological makeup, it is imperative that we understand how inherited variability influences cancer phenotypes, how it can confound experiments and how it can be exploited to reveal new truths about cancer biology.
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Affiliation(s)
- Kent W Hunter
- Laboratory of Cancer Biology and Genetics, National Cancer Institute, National Institutes of Health, 37/5046, 37 Convent Drive, Bethesda, Maryland 20892-4264, USA.
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15
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Ramsey KM, Bass J. Circadian clocks in fuel harvesting and energy homeostasis. COLD SPRING HARBOR SYMPOSIA ON QUANTITATIVE BIOLOGY 2011; 76:63-72. [PMID: 21890641 PMCID: PMC3970906 DOI: 10.1101/sqb.2011.76.010546] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/13/2023]
Abstract
Circadian systems have evolved in plants, eubacteria, neurospora, and the metazoa as a mechanism to optimize energy acquisition and storage in synchrony with the rotation of the Earth on its axis. In plants, circadian clocks drive the expression of genes involved in oxygenic photosynthesis during the light and nitrogen fixation during the dark, repeating this cycle each day. In mammals, the core clock in the suprachiasmatic nucleus (SCN) functions to entrain extra-SCN and peripheral clocks to the light cycle, including regions central to energy homeostasis and sleep, as well as peripheral tissues involved in glucose and lipid metabolism. Tissue-specific gene targeting has shown a primary role of clock genes in endocrine pancreas insulin secretion, indicating that local clocks play a cell-autonomous role in organismal homeostasis. A present focus is to dissect the consequences of clock disruption on modulation of nuclear hormone receptor signaling and on posttranscriptional regulation of intermediary metabolism. Experimental genetic studies have pointed toward extensive interplay between circadian and metabolic systems and offer a means to dissect the impact of local tissue molecular clocks on fuel utilization across the sleep-wake cycle.
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Affiliation(s)
- K M Ramsey
- Division of Endocrinology, Metabolism and Molecular Medicine, Feinberg School of Medicine and Department of Neurobiology and Physiology, Northwestern University, Chicago, Illinois 60611-3015, USA
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16
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Lu SY, Jin Y, Li X, Sheppard P, Bock ME, Sheikh F, Duckworth ML, Cattini PA. Embryonic survival and severity of cardiac and craniofacial defects are affected by genetic background in fibroblast growth factor-16 null mice. DNA Cell Biol 2010; 29:407-15. [PMID: 20618076 DOI: 10.1089/dna.2010.1024] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Disruption of the X-chromosome fibroblast growth factor 16 (Fgf-16) gene, a member of the FGF-9 subfamily with FGF-20, was linked with an effect on cardiac development in two independent studies. However, poor trabeculation with lethality by embryonic day (E) 11.5 was associated with only one, involving maintenance in Black Swiss (Bsw) versus C57BL/6 mice. The aim of this study was to examine the potential influence of genetic background through breeding the null mutation onto an alternate (C57BL/6) background. After three generations, 25% of Fgf-16(-/Y) mice survived to adulthood, which could be reversed by reducing the contribution of the C57BL/6 genetic background by back crossing to another strain. There was no significant difference between FGF-9 and FGF-20 RNA levels in Fgf-16 null versus wild-type mice regardless of strain. However, FGF-8 RNA levels were reduced significantly in Bsw but not C57BL/6 mice. FGF-8 is linked to anterior heart development and like the FGF-9 subfamily is reportedly expressed at E10.5. Like FGF-16, neuregulin as well as signaling via ErbB2 and ErbB4 receptors have been linked to trabeculae formation and cardiac development around E10.5. Basal neuregulin, ErbB2, and ErbB4 as well as FGF-8, FGF-9, and FGF-16 RNA levels varied in Bsw versus C57BL/6 mice. These data are consistent with the ability of genetic background to modify the phenotype and affect embryonic survival in Fgf-16 null mice.
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Affiliation(s)
- Shun Yan Lu
- Ontario Cancer Institute/Princess Margaret Hospital, Toronto, Ontario, Canada
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17
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Placental and embryonic growth restriction in mice with reduced function epidermal growth factor receptor alleles. Genetics 2009; 183:207-18. [PMID: 19564486 DOI: 10.1534/genetics.109.104372] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Embryos lacking an epidermal growth factor receptor (EGFR) exhibit strain-specific defects in placental development that can result in mid-gestational embryonic lethality. To determine the level of EGFR signaling required for normal placental development, we characterized congenic strains homozygous for the hypomorphic Egfr(wa2) allele or heterozygous for the antimorphic Egfr(Wa5) allele. Egfr(wa2) homozygous embryos and placentas exhibit strain-dependent growth restriction at 15.5 days post-coitus while Egfr(Wa5) heterozygous placentas are only slightly reduced in size with no effect on embryonic growth. Egfr(wa2) homozygous placentas have a reduced spongiotrophoblast layer in some strains, while spongiotrophoblasts and glycogen cells are almost completely absent in others. Our results demonstrate that more EGFR signaling occurs in Egfr(Wa5) heterozygotes than in Egfr(wa2) homozygotes and suggest that Egfr(wa2) homozygous embryos model EGFR-mediated intrauterine growth restriction in humans. We also consistently observed differences between strains in wild-type placenta and embryo size as well as in the cellular composition and expression of trophoblast cell subtype markers and propose that differential expression in the placenta of Glut3, a glucose transporter essential for normal embryonic growth, may contribute to strain-dependent differences in intrauterine growth restriction caused by reduced EGFR activity.
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18
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Barrick CJ, Roberts RB, Rojas M, Rajamannan NM, Suitt CB, O'Brien KD, Smyth SS, Threadgill DW. Reduced EGFR causes abnormal valvular differentiation leading to calcific aortic stenosis and left ventricular hypertrophy in C57BL/6J but not 129S1/SvImJ mice. Am J Physiol Heart Circ Physiol 2009; 297:H65-75. [PMID: 19448146 DOI: 10.1152/ajpheart.00866.2008] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Epidermal growth factor receptor (EGFR) signaling contributes to aortic valve development in mice. Because developmental phenotypes in Egfr-null mice are dependent on genetic background, the hypomorphic Egfr(wa2) allele was made congenic on C57BL/6J (B6) and 129S1/SvImJ (129) backgrounds and used to identify the underlying cellular cause of EGFR-related aortic valve abnormalities. Egfr(wa2/wa2) mice on both genetic backgrounds develop aortic valve hyperplasia. Many B6-Egfr(wa2/wa2) mice die before weaning, and those surviving to 3 mo of age or older develop severe left ventricular hypertrophy and heart failure. The cardiac phenotype was accompanied by significantly thicker aortic cusps and larger transvalvular gradients in B6-Egfr(wa2/wa2) mice compared with heterozygous controls and age-matched Egfr(wa2) homozygous mice on either 129 or B6129F1 backgrounds. Histological analysis revealed cellular changes in B6-Egfr(wa2/wa2) aortic valves underlying elevated pressure gradients and progression to heart failure, including increased cellular proliferation, ectopic cartilage formation, extensive calcification, and inflammatory infiltrate, mimicking changes seen in human calcific aortic stenosis. Despite having congenitally enlarged valves, 129 and B6129F1-Egfr(wa2/wa2) mice have normal lifespans, absence of left ventricular hypertrophy, and normal systolic function. These results show the requirement of EGFR activity for normal valvulogenesis and demonstrate that dominantly acting genetic modifiers curtail pathological changes in congenitally deformed valves. These studies provide a novel model of aortic sclerosis and stenosis and suggest that long-term inhibition of EGFR signaling for cancer therapy may have unexpected consequences on aortic valves in susceptible individuals.
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Affiliation(s)
- Cordelia J Barrick
- Department of Genetics, University of North Carolina, Chapel Hill, NC, USA
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19
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Lee TC, Threadgill DW. Generation and validation of mice carrying a conditional allele of the epidermal growth factor receptor. Genesis 2009; 47:85-92. [PMID: 19115345 DOI: 10.1002/dvg.20464] [Citation(s) in RCA: 84] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
Abstract
The epidermal growth factor receptor (EGFR) is important for normal homeostasis in a variety of tissues and, when abnormally expressed or mutated, contributes to the development of many diseases. However, in vivo functional studies are hindered by the lack of adult mice lacking EGFR because of the pre- and postnatal lethality of EGFR deficient mice. We generated a conditional allele of Egfr (Egfr(tm1Dwt)) by flanking exon 3 with loxP sites in order to investigate tissue-specific functions of this widely expressed receptor tyrosine kinase. The activity of the Egfr(tm1Dwt) allele is indistinguishable from wildtype Egfr. Conversely, the Egfr(Delta) allele, generated by Cre-mediated deletion of exon 3 using the germline EIIa-Cre transgenic line, functions as a null allele. Egfr(Delta/Delta) embryos that have complete ablation of EGFR activity and die at mid-gestation with placental defects identical to those reported for mice homozygous for the Egfr(tm1Mag) null allele. We also inactivated the Egfr(tm1Dwt) allele tissue-specifically in the skin epithelium using the K14-Cre transgenic line. These mice were viable but exhibited wavy coat hair remarkably similar to mice homozygous for the Egfr(wa2) hypomorphic allele or heterozygous for the Egfr(Wa5) antimorphic allele. These results suggest that the hairless phenotype of Egfr nullizygous mice is not solely due to absence of EGFR in the epithelium, but that EGFR activity is required also in skin stromal cells for normal hair morphogenesis. This new mouse model should have wide utility to inactivate Egfr conditionally for functional analysis of EGFR in adult tissues and disease states.
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Affiliation(s)
- Tang-Cheng Lee
- Department of Genetics, University of North Carolina, Chapel Hill, North Carolina 27599, USA
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20
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Takahashi JS, Shimomura K, Kumar V. Searching for genes underlying behavior: lessons from circadian rhythms. Science 2008; 322:909-12. [PMID: 18988844 DOI: 10.1126/science.1158822] [Citation(s) in RCA: 73] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
The success of forward genetic (from phenotype to gene) approaches to uncover genes that drive the molecular mechanism of circadian clocks and control circadian behavior has been unprecedented. Links among genes, cells, neural circuits, and circadian behavior have been uncovered in the Drosophila and mammalian systems, demonstrating the feasibility of finding single genes that have major effects on behavior. Why was this approach so successful in the elucidation of circadian rhythms? This article explores the answers to this question and describes how the methods used successfully for identifying the molecular basis of circadian rhythms can be applied to other behaviors such as anxiety, addiction, and learning and memory.
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Affiliation(s)
- Joseph S Takahashi
- Howard Hughes Medical Institute, Northwestern University, Evanston, IL 60208, USA.
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21
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Gelling RW, Yan W, Al-Noori S, Pardini A, Morton GJ, Ogimoto K, Schwartz MW, Dempsey PJ. Deficiency of TNFalpha converting enzyme (TACE/ADAM17) causes a lean, hypermetabolic phenotype in mice. Endocrinology 2008; 149:6053-64. [PMID: 18687778 PMCID: PMC2734496 DOI: 10.1210/en.2008-0775] [Citation(s) in RCA: 59] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Energy homeostasis involves central nervous system integration of afferent inputs that coordinately regulate food intake and energy expenditure. Here, we report that adult homozygous TNFalpha converting enzyme (TACE)-deficient mice exhibit one of the most dramatic examples of hypermetabolism yet reported in a rodent system. Because this effect is not matched by increased food intake, mice lacking TACE exhibit a lean phenotype. In the hypothalamus of these mice, neurons in the arcuate nucleus exhibit intact responses to reduced fat mass and low circulating leptin levels, suggesting that defects in other components of the energy homeostasis system explain the phenotype of Tace(DeltaZn/DeltaZn) mice. Elevated levels of uncoupling protein-1 in brown adipose tissue from Tace(DeltaZn/DeltaZn) mice when compared with weight-matched controls suggest that deficient TACE activity is linked to increased sympathetic outflow. These findings collectively identify a novel and potentially important role for TACE in energy homeostasis.
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Affiliation(s)
- Richard W Gelling
- Division of Metabolism, Endocrinology, and Nutrition, Department of Medicine, University of Washington, Seattle, Washington 98195, USA
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22
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Abstract
There are four members of the EGFR family: EGFR, erbB2, erbB3 and erbB4. These receptors form ligand-activated oligomers which regulate intracellular processes via an oligomeric tyrosine kinase scaffold. The receptors are activated when the extracellular domain undergoes a conformational change which facilitates either homo- or hetero-oligomerization with other family members. The absence of one EGFR family member leads to embryonic or early post-natal death due to implantation, central nervous system or cardiac defects. Many mouse models of defective or deficient EGFR family members are available for studying physiology and/or pathology of EGFR family members. Sophisticated antibody and kinase inhibitors which target different family members have been designed, produced. EGFR and erbB2 are frequently activated, over expressed or mutated in many common cancers and the antagonists and/or inhibitors of EGFR and/or erbB2 signalling have already been shown to have therapeutic benefits for cancer patients.
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Affiliation(s)
- Antony W Burgess
- Ludwig Institute for cancer Research, Melbourne, Victoria, Australia.
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23
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Schlichting CD. Hidden Reaction Norms, Cryptic Genetic Variation, and Evolvability. Ann N Y Acad Sci 2008; 1133:187-203. [DOI: 10.1196/annals.1438.010] [Citation(s) in RCA: 192] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
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24
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Dackor J, Strunk KE, Wehmeyer MM, Threadgill DW. Altered trophoblast proliferation is insufficient to account for placental dysfunction in Egfr null embryos. Placenta 2007; 28:1211-8. [PMID: 17822758 PMCID: PMC2121666 DOI: 10.1016/j.placenta.2007.07.005] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/18/2007] [Revised: 07/22/2007] [Accepted: 07/23/2007] [Indexed: 01/27/2023]
Abstract
Homozygosity for the Egfr(tm1Mag) null allele in mice leads to genetic background dependent placental abnormalities and embryonic lethality. Molecular mechanisms or genetic modifiers that differentiate strains with surviving versus non-surviving Egfr nullizygous embryos have yet to be identified. Egfr transcripts in wildtype placenta were quantified by ribonuclease protection assay (RPA) and the lowest level of Egfr mRNA expression was found to coincide with Egfr(tm1Mag) homozygous lethality. Immunohistochemical analysis of ERBB family receptors, ERBB2, ERBB3, and ERBB4, showed similar expression between Egfr wildtype and null placentas indicating that Egfr null trophoblast do not up-regulate these receptors to compensate for EGFR deficiency. Significantly fewer numbers of bromodeoxyuridine (BrdU) positive trophoblast were observed in Egfr nullizygous placentas and Cdc25a and Myc, genes associated with proliferation, were significantly down-regulated in null placentas. However, strains with both mild and severe placental phenotypes exhibit reduced proliferation suggesting that this defect alone does not account for strain-specific embryonic lethality. Consistent with this hypothesis, intercrosses generating mice null for cell cycle checkpoint genes (Trp53, Rb1, Cdkn1a, Cdkn1b or Cdkn2c) in combination with Egfr deficiency did not increase survival of Egfr nullizygous embryos. Since complete development of the spongiotrophoblast compartment is not required for survival of Egfr nullizygous embryos, reduction of this layer that is commonly observed in Egfr nullizygous placentas likely accounts for the decrease in proliferation.
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Affiliation(s)
- J. Dackor
- Department of Genetics, , University of North Carolina, Chapel Hill, North Carolina 27599, USA
- Curriculum in Genetics and Molecular Biology, University of North Carolina, Chapel Hill, North Carolina 27599, USA
| | - K. E. Strunk
- Department of Genetics, , University of North Carolina, Chapel Hill, North Carolina 27599, USA
- Department of Cell and Developmental Biology, Vanderbilt University, Nashville, Tennessee 37221, USA
| | - M. M. Wehmeyer
- Department of Genetics, , University of North Carolina, Chapel Hill, North Carolina 27599, USA
| | - D. W. Threadgill
- Department of Genetics, , University of North Carolina, Chapel Hill, North Carolina 27599, USA
- Curriculum in Genetics and Molecular Biology, University of North Carolina, Chapel Hill, North Carolina 27599, USA
- Carolina Center for Genome Sciences, University of North Carolina, Chapel Hill, North Carolina 27599, USA
- **Corresponding author: David Threadgill, Department of Genetics, CB#7264, University of North Carolina, Chapel Hill, North Carolina 27599, Tel: 919-843-6472, Fax: 919-966-3292, E-mail:
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25
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Li N, Boyd K, Dempsey PJ, Vignali DAA. Non-Cell Autonomous Expression of TNF-α-Converting Enzyme ADAM17 Is Required for Normal Lymphocyte Development. THE JOURNAL OF IMMUNOLOGY 2007; 178:4214-21. [PMID: 17371977 DOI: 10.4049/jimmunol.178.7.4214] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
TNF-alpha converting enzyme (TACE; ADAM17), a member of the ADAM (a disintegrin and metalloprotease) family of metalloproteases, has been shown to cleave a wide variety of cell surface proteins of immunological importance. Due to the broad expression of TACE and the early postnatal lethality of TACE-deficient mice, it has been difficult to assess the role of TACE in lymphocyte development. Indeed, it is not known whether hemopoietic and/or nonhemopoietic expression of TACE is required for normal lymphocyte development. In the current study, we analyzed the lymphoid system of tace(DeltaZn/DeltaZn) mice and tace(DeltaZn/DeltaZn) bone marrow RAG1(-/-) recipients. Our results clearly show that nonlymphocyte expression of TACE is required for normal lymphocyte development and lymphoid organ structure. Lack of TACE function resulted in a partial block in T cell development at the double-negative 4:double-positive transition in the thymus, a loss of B cell development/maturation in the spleen, and a lack of B cell follicle and germinal center formation in the spleen. Thus, TACE serves as a lymphocyte extrinsic factor that is essential for normal T development and peripheral B cell maturation.
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Affiliation(s)
- Nianyu Li
- Department of Immunology, St. Jude Children's Research Hospital, 332 North Lauderdale, Memphis, TN 38105, USA
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26
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Roberts RB, Thompson CL, Lee D, Mankinen RW, Sancar A, Threadgill DW. Wildtype epidermal growth factor receptor (Egfr) is not required for daily locomotor or masking behavior in mice. J Circadian Rhythms 2006; 4:15. [PMID: 17109754 PMCID: PMC1657032 DOI: 10.1186/1740-3391-4-15] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2006] [Accepted: 11/16/2006] [Indexed: 11/20/2022] Open
Abstract
Background Recent studies have implicated the epidermal growth factor receptor (EGFR) within the subparaventricular zone as being a major mediator of locomotor and masking behaviors in mice. The results were based on small cohorts of mice homozygous for the hypomorphic Egfrwa2 allele on a mixed, genetically uncontrolled background, and on intraventricular infusion of exogenous EGFR ligands. Subsequenlty, a larger study using the same genetically mixed background failed to replicate the original findings. Since both previous approaches were susceptible to experimental artifacts related to an uncontrolled genetic background, we analyzed the locomotor behaviors in Egfrwa2 mutant mice on genetically defined, congenic backgrounds. Methods Mice carrying the Egfrwa2 hypomorphic allele were bred to congenicity by backcrossing greater than ten generations onto C57BL/6J and 129S1/SvImJ genetic backgrounds. Homozygous Egfrwa2 mutant and wildtype littermates were evaluated for defects in locomotor and masking behaviors. Results Mice homozygous for Egfrwa2 showed normal daily locomotor activity and masking indistinguishable from wildtype littermates at two light intensities (200–300 lux and 400–500 lux). Conclusion Our results demonstrate that reduced EGFR activity alone is insufficient to perturb locomotor and masking behaviors in mice. Our results also suggest that other uncontrolled genetic or environmental parameters confounded previous experiments linking EGFR activity to daily locomotor activity and provide a cautionary tale for genetically uncontrolled studies.
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Affiliation(s)
- Reade B Roberts
- Department of Genetics, CB 7264, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA
| | - Carol L Thompson
- Department of Biochemistry, CB 7260, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA
| | - Daekee Lee
- Department of Genetics, CB 7264, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA
| | - Richard W Mankinen
- Department of Genetics, CB 7264, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA
| | - Aziz Sancar
- Department of Biochemistry, CB 7260, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA
| | - David W Threadgill
- Department of Genetics, CB 7264, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA
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27
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Lee D, Cross SH, Strunk KE, Morgan JE, Bailey CL, Jackson IJ, Threadgill DW. Wa5 is a novel ENU-induced antimorphic allele of the epidermal growth factor receptor. Mamm Genome 2005; 15:525-36. [PMID: 15366372 DOI: 10.1007/s00335-004-2384-2] [Citation(s) in RCA: 46] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
Mice heterozygous for the N-ethyl-N-nitrosourea-induced Waved-5 (Wa5) mutation, isolated in a screen for dominant, visible mutations, exhibit a wavy coat similar to mice homozygous for the recessive Tgfa wa1 or Egfr wa2 alleles. In this study, we show that Wa5 is a new allele of Egfr (Egfr Wa5) containing a missense mutation within the coding region for the highly conserved DFG motif of the tyrosine kinase domain. In vivo analysis of placental development, modification of Apc Min tumorigenesis, and levels of EGF-dependent EGFR phosphorylation demonstrates that Egfr Wa5 functions as an antimorphic allele, recapitulating many abnormalities associated with reduced EGFR activity. Furthermore, Egfr wa5 enhances Egfr Wa2 compound or Tgfa tm1Dcl double mutants exposing additional EGFR-dependent phenotypes. In vitro characterization shows that the antimorphic property of Egfr Wa5 is caused by a kinase-dead receptor acting as a dominant negative.
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Affiliation(s)
- Daekee Lee
- Department of Genetics, University of North Carolina School of Medicine, CB#7264, Chapel Hill, North Carolina, 27599, USA
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