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Mechanosensing by β1 integrin induces angiocrine signals for liver growth and survival. Nature 2018; 562:128-132. [PMID: 30258227 DOI: 10.1038/s41586-018-0522-3] [Citation(s) in RCA: 110] [Impact Index Per Article: 18.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2016] [Accepted: 08/16/2018] [Indexed: 02/06/2023]
Abstract
Angiocrine signals derived from endothelial cells are an important component of intercellular communication and have a key role in organ growth, regeneration and disease1-4. These signals have been identified and studied in multiple organs, including the liver, pancreas, lung, heart, bone, bone marrow, central nervous system, retina and some cancers1-4. Here we use the developing liver as a model organ to study angiocrine signals5,6, and show that the growth rate of the liver correlates both spatially and temporally with blood perfusion to this organ. By manipulating blood flow through the liver vasculature, we demonstrate that vessel perfusion activates β1 integrin and vascular endothelial growth factor receptor 3 (VEGFR3). Notably, both β1 integrin and VEGFR3 are strictly required for normal production of hepatocyte growth factor, survival of hepatocytes and liver growth. Ex vivo perfusion of adult mouse liver and in vitro mechanical stretching of human hepatic endothelial cells illustrate that mechanotransduction alone is sufficient to turn on angiocrine signals. When the endothelial cells are mechanically stretched, angiocrine signals trigger in vitro proliferation and survival of primary human hepatocytes. Our findings uncover a signalling pathway in vascular endothelial cells that translates blood perfusion and mechanotransduction into organ growth and maintenance.
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Singh AP, Foley J, Tandon A, Phadke D, Karimi Kinyamu H, Archer TK. A role for BRG1 in the regulation of genes required for development of the lymphatic system. Oncotarget 2017; 8:54925-54938. [PMID: 28903392 PMCID: PMC5589631 DOI: 10.18632/oncotarget.18976] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2017] [Accepted: 06/16/2017] [Indexed: 12/02/2022] Open
Abstract
Lymphatic vasculature is an important part of the cardiovascular system with multiple functions, including regulation of the return of interstitial fluid (lymph) to the bloodstream, immune responses, and fat absorption. Consequently, lymphatic vasculature defects are involved in many pathological processes, including tumor metastasis and lymphedema. BRG1 is an important player in the developmental window when the lymphatic system is initiated. In the current study, we used tamoxifen inducible Rosa26CreERT2-BRG1floxed/floxed mice that allowed temporal analysis of the impact of BRG1 inactivation in the embryo. The BRG1floxed/floxed/Cre-TM embryos exhibited edema and hemorrhage at embryonic day-13 and began to die. BRG1 deficient embryos had abnormal lymphatic sac linings with fewer LYVE1 positive lymphatic endothelial cells. Indeed, loss of BRG1 attenuated expression of a subset of lymphatic genes in-vivo. Furthermore, BRG1 binds at the promoters of COUP-TFII and LYVE1, suggesting that BRG1 modulates expression of these genes in the developing embryos. Conversely, re-expression of BRG1 in cells lacking endogenous BRG1 resulted in induction of lymphatic gene expression in-vitro, suggesting that BRG1 was both required and sufficient for lymphatic gene expression. These studies provide important insights into intrinsic regulation of BRG1-mediated lymphatic-gene expression, and further an understanding of lymphatic gene dysregulation in lymphedema and other disease conditions.
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Affiliation(s)
- Ajeet Pratap Singh
- Chromatin and Gene Expression Section, Epigenetics and Stem Cell Biology Laboratory, National Institute of Environmental Health Sciences, National Institutes of Health, Research Triangle Park, North Carolina, USA.,Present address: Cornell University, College of Veterinary Medicine, Ithaca, New York, USA
| | - Julie Foley
- Special Techniques Group, Cellular and Molecular Pathology Branch, National Institute of Environmental Health Sciences, National Institutes of Health, Research Triangle Park, North Carolina, USA
| | - Arpit Tandon
- Sciome.com, National Institute of Environmental Health Sciences, National Institutes of Health, Research Triangle Park, North Carolina, USA
| | - Dhiral Phadke
- Sciome.com, National Institute of Environmental Health Sciences, National Institutes of Health, Research Triangle Park, North Carolina, USA
| | - H Karimi Kinyamu
- Chromatin and Gene Expression Section, Epigenetics and Stem Cell Biology Laboratory, National Institute of Environmental Health Sciences, National Institutes of Health, Research Triangle Park, North Carolina, USA
| | - Trevor K Archer
- Chromatin and Gene Expression Section, Epigenetics and Stem Cell Biology Laboratory, National Institute of Environmental Health Sciences, National Institutes of Health, Research Triangle Park, North Carolina, USA
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Gerhardt C, Lier JM, Burmühl S, Struchtrup A, Deutschmann K, Vetter M, Leu T, Reeg S, Grune T, Rüther U. The transition zone protein Rpgrip1l regulates proteasomal activity at the primary cilium. J Cell Biol 2015; 210:115-33. [PMID: 26150391 PMCID: PMC4494006 DOI: 10.1083/jcb.201408060] [Citation(s) in RCA: 66] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023] Open
Abstract
Rpgrip1l regulates proteasomal activity at the basal body via Psmd2 and thereby controls ciliary signaling. Mutations in RPGRIP1L result in severe human diseases called ciliopathies. To unravel the molecular function of RPGRIP1L, we analyzed Rpgrip1l−/− mouse embryos, which display a ciliopathy phenotype and die, at the latest, around birth. In these embryos, cilia-mediated signaling was severely disturbed. Defects in Shh signaling suggested that the Rpgrip1l deficiency causes an impairment of protein degradation and protein processing. Indeed, we detected a cilia-dependent decreased proteasomal activity in the absence of Rpgrip1l. We found different proteasomal components localized to cilia and identified Psmd2, a component of the regulatory proteasomal 19S subunit, as an interaction partner for Rpgrip1l. Quantifications of proteasomal substrates demonstrated that Rpgrip1l regulates proteasomal activity specifically at the basal body. Our study suggests that Rpgrip1l controls ciliary signaling by regulating the activity of the ciliary proteasome via Psmd2.
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Affiliation(s)
- Christoph Gerhardt
- Institute for Animal Developmental and Molecular Biology, Heinrich-Heine University Düsseldorf, 40225 Düsseldorf, Germany
| | - Johanna Maria Lier
- Institute for Animal Developmental and Molecular Biology, Heinrich-Heine University Düsseldorf, 40225 Düsseldorf, Germany
| | - Stephan Burmühl
- Institute for Animal Developmental and Molecular Biology, Heinrich-Heine University Düsseldorf, 40225 Düsseldorf, Germany
| | - Andreas Struchtrup
- Institute for Animal Developmental and Molecular Biology, Heinrich-Heine University Düsseldorf, 40225 Düsseldorf, Germany
| | - Kathleen Deutschmann
- Institute for Animal Developmental and Molecular Biology, Heinrich-Heine University Düsseldorf, 40225 Düsseldorf, Germany
| | - Maik Vetter
- Institute for Animal Developmental and Molecular Biology, Heinrich-Heine University Düsseldorf, 40225 Düsseldorf, Germany
| | - Tristan Leu
- Institute for Animal Developmental and Molecular Biology, Heinrich-Heine University Düsseldorf, 40225 Düsseldorf, Germany
| | - Sandra Reeg
- Department of Nutritional Toxicology, Institute of Nutrition, Friedrich-Schiller University Jena, 07743 Jena, Germany
| | - Tilman Grune
- Department of Nutritional Toxicology, Institute of Nutrition, Friedrich-Schiller University Jena, 07743 Jena, Germany
| | - Ulrich Rüther
- Institute for Animal Developmental and Molecular Biology, Heinrich-Heine University Düsseldorf, 40225 Düsseldorf, Germany
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Kalaskar VK, Lauderdale JD. Mouse embryonic development in a serum-free whole embryo culture system. J Vis Exp 2014. [PMID: 24637443 DOI: 10.3791/50803] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023] Open
Abstract
Mid-gestation stage mouse embryos were cultured utilizing a serum-free culture medium prepared from commercially available stem cell media supplements in an oxygenated rolling bottle culture system. Mouse embryos at E10.5 were carefully isolated from the uterus with intact yolk sac and in a process involving precise surgical maneuver the embryos were gently exteriorized from the yolk sac while maintaining the vascular continuity of the embryo with the yolk sac. Compared to embryos prepared with intact yolk sac or with the yolk sac removed, these embryos exhibited superior survival rate and developmental progression when cultured under similar conditions. We show that these mouse embryos, when cultured in a defined medium in an atmosphere of 95% O2 / 5% CO2 in a rolling bottle culture apparatus at 37 °C for 16-40 hr, exhibit morphological growth and development comparable to the embryos developing in utero. We believe this method will be useful for investigators needing to utilize whole embryo culture to study signaling interactions important in embryonic organogenesis.
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Affiliation(s)
- Vijay K Kalaskar
- Neuroscience Division of the Biomedical & Health Sciences Institute, University of Georgia
| | - James D Lauderdale
- Neuroscience Division of the Biomedical & Health Sciences Institute, University of Georgia; Department of Cellular Biology, University of Georgia;
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Visualization of lymphatic vessel development, growth, and function. ADVANCES IN ANATOMY, EMBRYOLOGY, AND CELL BIOLOGY 2014; 214:167-86. [PMID: 24276894 DOI: 10.1007/978-3-7091-1646-3_13] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
Despite their important physiological and pathophysiological functions, lymphatic endothelial cells and lymphatic vessels remain less well studied compared to the blood vascular system. Lymphatic endothelium differentiates from venous blood vascular endothelium after initial arteriovenous differentiation. Only recently by the use of light sheet microscopy, the precise mechanism of separation of the first lymphatic endothelial progenitors from the cardinal vein has been described as delamination followed by mesenchymal cell migration of lymphatic endothelial cells. Dorsolaterally of the embryonic cardinal vein, lymphatic endothelial cells reaggregate to form the first lumenized lymphatic vessels, the dorsal peripheral longitudinal vessel and the more ventrally positioned primordial thoracic duct. Despite this progress in our understanding of the first lymph vessel formation, intravital observation of lymphatic vessel behavior in the intact organism, during development and in the adult, is prerequisite to a precise understanding of this tissue. Transgenic models and two-photon microscopy, in combination with optical windows, have made live intravital imaging possible: however, new imaging modalities and novel approaches promise gentler, more physiological, and longer intravital imaging of lymphatic vessels.
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Update March 2013. Lymphat Res Biol 2013. [DOI: 10.1089/lrb.2013.1113] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
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