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Wei Z, Lei J, Shen F, Dai Y, Sun Y, Liu Y, Dai Y, Jian Z, Wang S, Chen Z, Liao K, Hong S. Cavin1 Deficiency Causes Disorder of Hepatic Glycogen Metabolism and Neonatal Death by Impacting Fenestrations in Liver Sinusoidal Endothelial Cells. ADVANCED SCIENCE (WEINHEIM, BADEN-WURTTEMBERG, GERMANY) 2020; 7:2000963. [PMID: 33042738 PMCID: PMC7539207 DOI: 10.1002/advs.202000963] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/16/2020] [Revised: 07/10/2020] [Indexed: 05/05/2023]
Abstract
It has been reported that Cavin1 deficiency causes lipodystrophy in both humans and mice by affecting lipid metabolism. The ablation of Cavin1 in rodents also causes a significant deviation from Mendelian ratio at weaning in a background-dependent manner, suggesting the presence of undiscovered functions of Cavin1. In the current study, the results show that Cavin1 deficiency causes neonatal death in C57BL/6J mice by dampening the storage and mobilization of glycogen in the liver, which leads to lethal neonatal hypoglycemia. Further investigation by electron microscopy reveals that Cavin1 deficiency impairs the fenestration in liver sinusoidal endothelial cells (LSECs) and impacts the permeability of endothelial barrier in the liver. Mechanistically, Cavin1 deficiency inhibits the RhoA-Rho-associated protein kinase 2-LIM domain kinase-Cofilin signaling pathway and suppresses the dynamics of the cytoskeleton, and eventually causes the reduction of fenestrae in LSECs. In addition, the defect of fenestration in LSECs caused by Cavin1 deficiency can be rescued by treatment with the F-actin depolymerization reagent latrunculin A. In summary, the current study reveals a novel function of Cavin1 on fenestrae formation in LSECs and liver glycogen metabolism, which provide an explanation for the neonatal death of Cavin1 null mice and a potential mechanism for metabolic disorders in patients with Cavin1 mutation.
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Affiliation(s)
- Zhuang Wei
- State Key Laboratory of Genetic Engineering and School of Life SciencesHuman Phenome InstituteFudan UniversityShanghai200433China
- Key Laboratory of Systems BiologyInnovation Center for Cell Signaling NetworkCAS Center for Excellence in Molecular Cell ScienceInstitute of Biochemistry and Cell BiologyShanghai Institutes for Biological SciencesCAS320 Yueyang RoadShanghai200031China
| | - Jigang Lei
- Key Laboratory of Systems BiologyInnovation Center for Cell Signaling NetworkCAS Center for Excellence in Molecular Cell ScienceInstitute of Biochemistry and Cell BiologyShanghai Institutes for Biological SciencesCAS320 Yueyang RoadShanghai200031China
- The Department of BiologyTongji UniversityShanghai200092China
| | - Feng Shen
- Department of Hepatobiliary SurgeryDongfeng HospitalHubei University of MedicineShiyanHubei442001China
| | - Yuxiang Dai
- Department of CardiologyZhongshan HospitalFudan UniversityShanghai Institute of Cardiovascular DiseaseShanghai200031P. R. China
| | - Yan Sun
- Masonic Medical Research Institute2150 Bleecker StUticaNY13501USA
| | - Yilian Liu
- State Key Laboratory of Genetic Engineering and School of Life SciencesHuman Phenome InstituteFudan UniversityShanghai200433China
| | - Yan Dai
- Key Laboratory of Systems BiologyInnovation Center for Cell Signaling NetworkCAS Center for Excellence in Molecular Cell ScienceInstitute of Biochemistry and Cell BiologyShanghai Institutes for Biological SciencesCAS320 Yueyang RoadShanghai200031China
- State Key Laboratory of Cell BiologyKey Laboratory of Systems BiologyInnovation Center for Cell Signaling NetworkCAS Center for Excellence in Molecular Cell ScienceInstitute of Biochemistry and Cell BiologyShanghai Institutes for Biological SciencesCAS320 Yueyang RoadShanghai200031China
| | - Zhijie Jian
- Department of Radiologythe First Affiliated Hospital of Xi'an Jiaotong UniversityXi'an710049China
| | - Shilong Wang
- The Department of BiologyTongji UniversityShanghai200092China
| | - Zhengjun Chen
- Key Laboratory of Systems BiologyInnovation Center for Cell Signaling NetworkCAS Center for Excellence in Molecular Cell ScienceInstitute of Biochemistry and Cell BiologyShanghai Institutes for Biological SciencesCAS320 Yueyang RoadShanghai200031China
- State Key Laboratory of Cell BiologyKey Laboratory of Systems BiologyInnovation Center for Cell Signaling NetworkCAS Center for Excellence in Molecular Cell ScienceInstitute of Biochemistry and Cell BiologyShanghai Institutes for Biological SciencesCAS320 Yueyang RoadShanghai200031China
| | - Kan Liao
- Key Laboratory of Systems BiologyInnovation Center for Cell Signaling NetworkCAS Center for Excellence in Molecular Cell ScienceInstitute of Biochemistry and Cell BiologyShanghai Institutes for Biological SciencesCAS320 Yueyang RoadShanghai200031China
| | - Shangyu Hong
- State Key Laboratory of Genetic Engineering and School of Life SciencesHuman Phenome InstituteFudan UniversityShanghai200433China
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Lafoz E, Ruart M, Anton A, Oncins A, Hernández-Gea V. The Endothelium as a Driver of Liver Fibrosis and Regeneration. Cells 2020; 9:E929. [PMID: 32290100 PMCID: PMC7226820 DOI: 10.3390/cells9040929] [Citation(s) in RCA: 72] [Impact Index Per Article: 18.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2020] [Revised: 04/05/2020] [Accepted: 04/06/2020] [Indexed: 02/07/2023] Open
Abstract
Liver fibrosis is a common feature of sustained liver injury and represents a major public health problem worldwide. Fibrosis is an active research field and discoveries in the last years have contributed to the development of new antifibrotic drugs, although none of them have been approved yet. Liver sinusoidal endothelial cells (LSEC) are highly specialized endothelial cells localized at the interface between the blood and other liver cell types. They lack a basement membrane and display open channels (fenestrae), making them exceptionally permeable. LSEC are the first cells affected by any kind of liver injury orchestrating the liver response to damage. LSEC govern the regenerative process initiation, but aberrant LSEC activation in chronic liver injury induces fibrosis. LSEC are also main players in fibrosis resolution. They maintain liver homeostasis and keep hepatic stellate cell and Kupffer cell quiescence. After sustained hepatic injury, they lose their phenotype and protective properties, promoting angiogenesis and vasoconstriction and contributing to inflammation and fibrosis. Therefore, improving LSEC phenotype is a promising strategy to prevent liver injury progression and complications. This review focuses on changes occurring in LSEC after liver injury and their consequences on fibrosis progression, liver regeneration, and resolution. Finally, a synopsis of the available strategies for LSEC-specific targeting is provided.
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Affiliation(s)
- Erica Lafoz
- Unidad de Hemodinámica Hepática, Servicio de Hepatología, Hospital Clínic, Universidad de Barcelona, Instituto de Investigaciones Biomédicas Augusto Pi Suñer (IDIBAPS), 08036 Barcelona, Spain; (E.L.); (M.R.); (A.A.); (A.O.)
| | - Maria Ruart
- Unidad de Hemodinámica Hepática, Servicio de Hepatología, Hospital Clínic, Universidad de Barcelona, Instituto de Investigaciones Biomédicas Augusto Pi Suñer (IDIBAPS), 08036 Barcelona, Spain; (E.L.); (M.R.); (A.A.); (A.O.)
| | - Aina Anton
- Unidad de Hemodinámica Hepática, Servicio de Hepatología, Hospital Clínic, Universidad de Barcelona, Instituto de Investigaciones Biomédicas Augusto Pi Suñer (IDIBAPS), 08036 Barcelona, Spain; (E.L.); (M.R.); (A.A.); (A.O.)
| | - Anna Oncins
- Unidad de Hemodinámica Hepática, Servicio de Hepatología, Hospital Clínic, Universidad de Barcelona, Instituto de Investigaciones Biomédicas Augusto Pi Suñer (IDIBAPS), 08036 Barcelona, Spain; (E.L.); (M.R.); (A.A.); (A.O.)
| | - Virginia Hernández-Gea
- Unidad de Hemodinámica Hepática, Servicio de Hepatología, Hospital Clínic, Universidad de Barcelona, Instituto de Investigaciones Biomédicas Augusto Pi Suñer (IDIBAPS), 08036 Barcelona, Spain; (E.L.); (M.R.); (A.A.); (A.O.)
- Centro de Investigación Biomédica en Red de Enfermedades Hepáticas y Digestivas (CIBERehd), Instituto de Salud Carlos III, 28029 Madrid, Spain
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Poisson J, Lemoinne S, Boulanger C, Durand F, Moreau R, Valla D, Rautou PE. Liver sinusoidal endothelial cells: Physiology and role in liver diseases. J Hepatol 2017; 66:212-227. [PMID: 27423426 DOI: 10.1016/j.jhep.2016.07.009] [Citation(s) in RCA: 546] [Impact Index Per Article: 78.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/24/2016] [Revised: 07/05/2016] [Accepted: 07/07/2016] [Indexed: 12/13/2022]
Abstract
Liver sinusoidal endothelial cells (LSECs) are highly specialized endothelial cells representing the interface between blood cells on the one side and hepatocytes and hepatic stellate cells on the other side. LSECs represent a permeable barrier. Indeed, the association of 'fenestrae', absence of diaphragm and lack of basement membrane make them the most permeable endothelial cells of the mammalian body. They also have the highest endocytosis capacity of human cells. In physiological conditions, LSECs regulate hepatic vascular tone contributing to the maintenance of a low portal pressure despite the major changes in hepatic blood flow occurring during digestion. LSECs maintain hepatic stellate cell quiescence, thus inhibiting intrahepatic vasoconstriction and fibrosis development. In pathological conditions, LSECs play a key role in the initiation and progression of chronic liver diseases. Indeed, they become capillarized and lose their protective properties, and they promote angiogenesis and vasoconstriction. LSECs are implicated in liver regeneration following acute liver injury or partial hepatectomy since they renew from LSECs and/or LSEC progenitors, they sense changes in shear stress resulting from surgery, and they interact with platelets and inflammatory cells. LSECs also play a role in hepatocellular carcinoma development and progression, in ageing, and in liver lesions related to inflammation and infection. This review also presents a detailed analysis of the technical aspects relevant for LSEC analysis including the markers these cells express, the available cell lines and the transgenic mouse models. Finally, this review provides an overview of the strategies available for a specific targeting of LSECs.
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Affiliation(s)
- Johanne Poisson
- INSERM, UMR-970, Paris Cardiovascular Research Center - PARCC, Paris, France; Université Paris Descartes, Sorbonne Paris Cité, Paris, France
| | - Sara Lemoinne
- INSERM, UMRS 938, Centre de Recherche Saint-Antoine, Université Pierre et Marie Curie Paris 6, Paris, France; Service d'hépatologie, Hôpital Saint-Antoine, APHP, Paris, France
| | - Chantal Boulanger
- INSERM, UMR-970, Paris Cardiovascular Research Center - PARCC, Paris, France; Université Paris Descartes, Sorbonne Paris Cité, Paris, France
| | - François Durand
- Service d'hépatologie, DHU Unity Hôpital Beaujon, APHP, Clichy, France; INSERM, UMR-1149, Centre de Recherche sur l'inflammation, Paris-Clichy, France; Université Denis Diderot-Paris 7, Sorbonne Paris Cité, 75018 Paris, France
| | - Richard Moreau
- Service d'hépatologie, DHU Unity Hôpital Beaujon, APHP, Clichy, France; INSERM, UMR-1149, Centre de Recherche sur l'inflammation, Paris-Clichy, France; Université Denis Diderot-Paris 7, Sorbonne Paris Cité, 75018 Paris, France
| | - Dominique Valla
- Service d'hépatologie, DHU Unity Hôpital Beaujon, APHP, Clichy, France; INSERM, UMR-1149, Centre de Recherche sur l'inflammation, Paris-Clichy, France; Université Denis Diderot-Paris 7, Sorbonne Paris Cité, 75018 Paris, France
| | - Pierre-Emmanuel Rautou
- INSERM, UMR-970, Paris Cardiovascular Research Center - PARCC, Paris, France; Université Paris Descartes, Sorbonne Paris Cité, Paris, France; Service d'hépatologie, DHU Unity Hôpital Beaujon, APHP, Clichy, France; INSERM, UMR-1149, Centre de Recherche sur l'inflammation, Paris-Clichy, France; Université Denis Diderot-Paris 7, Sorbonne Paris Cité, 75018 Paris, France.
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Cogger VC, Roessner U, Warren A, Fraser R, Le Couteur DG. A Sieve-Raft Hypothesis for the regulation of endothelial fenestrations. Comput Struct Biotechnol J 2013; 8:e201308003. [PMID: 24688743 PMCID: PMC3962122 DOI: 10.5936/csbj.201308003] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2013] [Revised: 07/31/2013] [Accepted: 08/11/2013] [Indexed: 01/13/2023] Open
Affiliation(s)
- Victoria C Cogger
- Centre for Education and Research on Ageing and ANZAC Research Institute, Concord Hospital and University of Sydney, Sydney NSW, Australia ; Charles Perkins Centre, University of Sydney NSW Australia
| | - Ute Roessner
- Metabolomics Australia and Australian Centre for Plant Functional Genomics, The University of Melbourne, 3010 Victoria, Australia
| | - Alessandra Warren
- Centre for Education and Research on Ageing and ANZAC Research Institute, Concord Hospital and University of Sydney, Sydney NSW, Australia ; Charles Perkins Centre, University of Sydney NSW Australia
| | - Robin Fraser
- Christchurch School of Medicine, University of Otago, Christchurch NZ
| | - David G Le Couteur
- Centre for Education and Research on Ageing and ANZAC Research Institute, Concord Hospital and University of Sydney, Sydney NSW, Australia ; Charles Perkins Centre, University of Sydney NSW Australia
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Svistounov D, Warren A, McNerney GP, Owen DM, Zencak D, Zykova SN, Crane H, Huser T, Quinn RJ, Smedsrød B, Le Couteur DG, Cogger VC. The Relationship between fenestrations, sieve plates and rafts in liver sinusoidal endothelial cells. PLoS One 2012; 7:e46134. [PMID: 23029409 PMCID: PMC3454341 DOI: 10.1371/journal.pone.0046134] [Citation(s) in RCA: 52] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2012] [Accepted: 08/28/2012] [Indexed: 01/22/2023] Open
Abstract
Fenestrations are transcellular pores in endothelial cells that facilitate transfer of substrates between blood and the extravascular compartment. In order to understand the regulation and formation of fenestrations, the relationship between membrane rafts and fenestrations was investigated in liver sinusoidal endothelial cells where fenestrations are grouped into sieve plates. Three dimensional structured illumination microscopy, scanning electron microscopy, internal reflectance fluorescence microscopy and two-photon fluorescence microscopy were used to study liver sinusoidal endothelial cells isolated from mice. There was an inverse distribution between sieve plates and membrane rafts visualized by structured illumination microscopy and the fluorescent raft stain, Bodipy FL C5 ganglioside GM1. 7-ketocholesterol and/or cytochalasin D increased both fenestrations and lipid-disordered membrane, while Triton X-100 decreased both fenestrations and lipid-disordered membrane. The effects of cytochalasin D on fenestrations were abrogated by co-administration of Triton X-100, suggesting that actin disruption increases fenestrations by its effects on membrane rafts. Vascular endothelial growth factor (VEGF) depleted lipid-ordered membrane and increased fenestrations. The results are consistent with a sieve-raft interaction, where fenestrations form in non-raft lipid-disordered regions of endothelial cells once the membrane-stabilizing effects of actin cytoskeleton and membrane rafts are diminished.
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Affiliation(s)
- Dmitri Svistounov
- Centre for Education and Research on Ageing and ANZAC Medical Research Institute, University of Sydney and Concord Hospital, Sydney, Australia
| | - Alessandra Warren
- Centre for Education and Research on Ageing and ANZAC Medical Research Institute, University of Sydney and Concord Hospital, Sydney, Australia
| | - Gregory P. McNerney
- NSF Center for Biophotonics Science and Technology, University of California Davis, Sacramento, California, United States of America
| | - Dylan M. Owen
- Centre for Vascular Research, University of New South Wales, Sydney, Australia
| | - Dusan Zencak
- Eskitis Institute, Griffith University, Brisbane, Australia
| | - Svetlana N. Zykova
- Centre for Education and Research on Ageing and ANZAC Medical Research Institute, University of Sydney and Concord Hospital, Sydney, Australia
| | - Harry Crane
- Centre for Education and Research on Ageing and ANZAC Medical Research Institute, University of Sydney and Concord Hospital, Sydney, Australia
| | - Thomas Huser
- NSF Center for Biophotonics Science and Technology, University of California Davis, Sacramento, California, United States of America
| | | | - Bård Smedsrød
- Department of Medical Biology, University of Tromso, Tromso, Norway
| | - David G. Le Couteur
- Centre for Education and Research on Ageing and ANZAC Medical Research Institute, University of Sydney and Concord Hospital, Sydney, Australia
- * E-mail:
| | - Victoria C. Cogger
- Centre for Education and Research on Ageing and ANZAC Medical Research Institute, University of Sydney and Concord Hospital, Sydney, Australia
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Abstract
Caveolae are a specialized subset of lipid domains that are prevalent on the plasma membrane of endothelial cells. They compartmentalize signal transduction molecules which regulate multiple endothelial functions including the production of nitric oxide (NO) by the caveolae resident enzyme endothelial NO synthase (eNOS). eNOS is one of the three isoforms of the NOS enzyme which generates NO upon the conversion of L-arginine to L-citrulline and it is regulated by multiple mechanisms. Caveolin negatively impact eNOS activity through direct interaction with the enzyme. Circulating factors known to modify cardiovascular disease risk also influence the activity of the enzyme. In particular, high density lipoprotein cholesterol (HDL) maintains the lipid environment in caveolae, thereby promoting the retention and function of eNOS in the domain and it also causes direct activation of eNOS via scavenger receptor class B, Type I (SR-BI)-induced kinase signaling. Estrogen binding to estrogen receptors (ER) in caveolae also activates eNOS and this occurs through G protein coupling and kinase activation. Discrete domains within SR-BI and ER mediating signal initiation in caveolae have been identified. Counteracting the promodulatory actions of HDL and estrogen, C-reactive protein (CRP) antagonizes eNOS through FcγRIIB, which is the sole inhibitory receptor for IgG. Through their actions on eNOS, estrogen and CRP also regulate endothelial cell growth and migration. Thus, signaling events in caveolae invoked by known circulating cardiovascular disease risk factors have major impact on eNOS and endothelial cell phenotypes of importance to cardiovascular health and disease.
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Affiliation(s)
- Chieko Mineo
- Department of Pediatrics, University of Texas Southwestern Medical Center, Dallas, TX, USA.
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7
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Biazik JM, Jahn KA, Braet F. Caveolae and caveolin-1 in reptilian liver. Micron 2011; 42:656-61. [DOI: 10.1016/j.micron.2011.03.005] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2010] [Revised: 03/10/2011] [Accepted: 03/12/2011] [Indexed: 11/26/2022]
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Vidal-Vanaclocha F. Architectural and Functional Aspects of the Liver with Implications for Cancer Metastasis. LIVER METASTASIS: BIOLOGY AND CLINICAL MANAGEMENT 2011. [DOI: 10.1007/978-94-007-0292-9_2] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
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Yang SF, Yang JY, Huang CH, Wang SN, Lu CP, Tsai CJ, Chai CY, Yeh YT. Increased caveolin-1 expression associated with prolonged overall survival rate in hepatocellular carcinoma. Pathology 2010; 42:438-45. [PMID: 20632820 DOI: 10.3109/00313025.2010.494293] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
AIMS Recent study indicates that the binding of caveolin-1 (CAV1), the essential constituent of caveolae, to endothelial nitric oxide synthase (eNOS) prevents nitric oxide (NO) production in cirrhotic human liver. However, their interplay in hepatocellular carcinoma (HCC) remains undetermined. METHODS Paraffin-embedded sections from 73 HCC patients were included in this study. The expression patterns of CAV1 and eNOS determined by immunohistochemistry were correlated with the clinicopathological characteristics and overall survival. RESULTS Although CAV1 expression did not correlate with any clinicopathological characteristic, increased CAV1 expression was associated with prolonged overall survival (p = 0.021), even when using the multivariate Cox's regression model (OR = 0.25, 95%CI = 0.08-0.72, p = 0.011). eNOS expression was correlated with an increased histological grade (p = 0.002) and intriguingly, the patients had a decreased overall survival when their lesions presented with high eNOS but low CAV1 expression concomitantly (p = 0.003). Meanwhile, the increased CAV1/eNOS merged level determined by immunofluorescence was significantly associated with a decreased histological grade and better overall survival (p = 0.023 and 0.001, respectively). CONCLUSIONS Our results suggest CAV1 may play a tumour-suppressive role and can serve as a predictive biomarker in HCC. The impacts of CAV1 on hepatocarcinogenesis may occur partly through its modulation of eNOS.
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Affiliation(s)
- Sheau-Fang Yang
- Department of Pathology, Kaohsiung Municipal Ta-Tung Hospital, Kaohsiung, Taiwan
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Warren A, Cogger VC, Arias IM, McCuskey RS, Le Couteur DG. Liver sinusoidal endothelial fenestrations in caveolin-1 knockout mice. Microcirculation 2010; 17:32-8. [PMID: 20141598 DOI: 10.1111/j.1549-8719.2009.00004.x] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
OBJECTIVE Fenestrations are pores in the liver sinusoidal endothelium that facilitate the transfer of particulate substrates between the sinusoidal lumen and hepatocytes. Fenestrations express caveolin-1 and have structural similarities to caveolae, therefore might be a form of caveolae and caveolin-1 may be integral to fenestration structure and function. Therefore, fenestrations were studied in the livers of caveolin-1 knockout mice. METHODS Scanning, transmission and immunogold electron microscopic techniques were used to study the liver sinusoidal endothelium and other tissues in caveolin-1 knockout and wild-type mice. RESULTS Comparison of fenestrations in wild-type and knockout mice did not reveal any differences on either scanning or transmission electron microscopy. The diameter of the fenestrations was not significantly different (74 +/- 13 nm knockout mice vs 78 +/- 12 nm wild-type mice) nor was the fenestration porosity (6.5 +/- 2.1 knockout vs 7.3 +/- 2.4% wild-type mice). In contrast, adipocytes and blood vessels in other tissues lacked caveolae in the knockout mice. Caveolin-1 immunogold of livers of wild-type mice indicated sparse expression in sinusoidal endothelial cells. CONCLUSIONS The normal structure of fenestrations in the liver sinusoidal endothelium is not dependent upon caveolin-1 and fenestrations are not a form of caveolae.
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Affiliation(s)
- Alessandra Warren
- Centre for Education and Research on Ageing and ANZAC Research Institute, University of Sydney and Concord RG Hospital, Sydney, Australia
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11
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Three-dimensional structured illumination microscopy of liver sinusoidal endothelial cell fenestrations. J Struct Biol 2010; 171:382-8. [PMID: 20570732 DOI: 10.1016/j.jsb.2010.06.001] [Citation(s) in RCA: 67] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2010] [Revised: 05/31/2010] [Accepted: 06/01/2010] [Indexed: 11/20/2022]
Abstract
Fenestrations are pores in liver sinusoidal endothelial cells that filter substrates and debris between the blood and hepatocytes. Fenestrations have significant roles in aging and the regulation of lipoproteins. However their small size (<200 nm) has prohibited any functional analysis by light microscopy. We employed structured illumination light microscopy to observe fenestrations in isolated rat liver sinusoidal endothelial cells with great clarity and spatial resolution. With this method, the three-dimensional structure of fenestrations (diameter 123+/-24 nm) and sieve plates was elucidated and it was shown that fenestrations occur in areas of abrupt cytoplasmic thinning (165+/-54 nm vs. 292+/-103 nm in non-fenestrated regions, P<0.0001). Sieve plates were not preferentially co-localized with fluorescently labeled F-actin stress fibers and endothelial nitric oxide synthase but appeared to occur in primarily attenuated non-raft regions of the cell membrane. Labyrinthine structures were not seen and all fenestrations were short cylindrical pores. In conclusion, three-dimensional structured illumination microscopy has enabled the unlimited power of fluorescent immunostaining and co-localization to reveal new structural and functional information about fenestrations and sieve plates.
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Braet F, Riches J, Geerts W, Jahn KA, Wisse E, Frederik P. Three-dimensional organization of fenestrae labyrinths in liver sinusoidal endothelial cells. Liver Int 2009; 29:603-13. [PMID: 18662275 DOI: 10.1111/j.1478-3231.2008.01836.x] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/13/2023]
Abstract
BACKGROUND/AIMS Liver sinusoidal endothelial cell (LSEC) fenestrae are membrane-bound pores that are grouped in sieve plates and act as a bidirectional guardian in regulating transendothelial liver transport. The high permeability of the endothelial lining is explained by the presence of fenestrae and by various membrane-bound transport vesicles. The question as to whether fenestrae relate to other transport compartments remains unclear and has been debated since their discovery almost 40 years ago. METHODS In this study, novel insights concerning the three-dimensional (3D) organization of the fenestrated cytoplasm were built on transmission electron tomographical observations on isolated and cultured whole-mount LSECs. Classical transmission electron microscopy and atomic force microscopy imaging was performed to accumulate cross-correlative structural evidence. RESULTS AND CONCLUSIONS The data presented here indicate that different arrangements of fenestrae have to be considered: i.e. open fenestrae that lack any structural obstruction mainly located in the thin peripheral cytoplasm and complexes of multifolded fenestrae organized as labyrinth-like structures that are found in the proximity of the perinuclear area. Fenestrae in labyrinths constitute about one-third of the total LSEC porosity. The 3D reconstructions also revealed that coated pits and small membrane-bound vesicles are exclusively interspersed in the non-fenestrated cytoplasmic arms.
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Affiliation(s)
- Filip Braet
- Australian Key Centre for Microscopy and Microanalysis, The University of Sydney, NSW, Australia.
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Cheluvappa R, Cogger VC, Kwun SY, O'Reilly JN, Le Couteur DG, Hilmer SN. Liver sinusoidal endothelial cells and acute non-oxidative hepatic injury induced by Pseudomonas aeruginosa pyocyanin. Int J Exp Pathol 2009; 89:410-8. [PMID: 19134050 DOI: 10.1111/j.1365-2613.2008.00602.x] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
The liver sinusoidal endothelial cell (LSEC) is damaged by many toxins, including oxidants and bacterial toxins. Any effect on LSECs of the Pseudomonas aeruginosa virulence factor, pyocyanin, may be relevant for systemic pseudomonal infections and liver transplantation. In this study, the effects of pyocyanin on in vivo rat livers and isolated LSECs were assessed using electron microscopy, immunohistochemistry and biochemistry. In particular, the effect on fenestrations, a crucial morphological aspect of LSECs was assessed. Pyocyanin treatment induced a dose-dependent reduction in fenestrations in isolated LSECs. In the intact liver, intraportal injection of pyocyanin (11.9 microM in blood) was associated with a reduction in endothelial porosity from 3.4 +/- 0.2% (n = 5) to 1.3 +/- 0.1% (n = 7) within 30 min. There were decreases in both diameter and frequency of fenestrations in the intact endothelium. There was also a decrease in endothelial thickness from 175.8 +/- 5.8 to 156.5 +/- 4.0 nm, an endothelial pathology finding previously unreported. Hepatocyte ultrastructure, liver function tests and immunohistochemical markers of oxidative stress (3-nitrotyrosine and malondialdehyde) were not affected. Pyocyanin induces significant ultrastructural changes in the LSEC in the absence of immunohistochemical evidence of oxidative stress or hepatocyte injury pointing to a novel mechanism for pyocyanin pathogenesis.
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Affiliation(s)
- Rajkumar Cheluvappa
- Centre for Education and Research on Ageing and ANZAC Research Institute, University of Sydney and Concord RG Hospital, Concord, NSW, Australia.
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Cogger VC, Arias IM, Warren A, McMahon AC, Kiss DL, Avery VM, Le Couteur DG. The response of fenestrations, actin, and caveolin-1 to vascular endothelial growth factor in SK Hep1 cells. Am J Physiol Gastrointest Liver Physiol 2008; 295:G137-G145. [PMID: 18497335 PMCID: PMC2494729 DOI: 10.1152/ajpgi.00069.2008] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
To study the regulation of fenestrations by vascular endothelial growth factor in liver sinusoidal endothelial cells, SK Hep1 cells were transfected with green fluorescence protein (GFP)-actin and GFP-caveolin-1. SK Hep1 cells had pores; some of which appeared to be fenestrations (diameter 55 +/- 28 nm, porosity 2.0 +/- 1.4%), rudimentary sieve plates, bristle-coated micropinocytotic vesicles and expressed caveolin-1, von Willebrand factor, vascular endothelial growth factor receptor-2, endothelial nitric oxide synthase and clathrin, but not CD31. There was avid uptake of formaldehyde serum albumin, consistent with endocytosis. Vascular endothelial growth factor caused an increase in porosity to 4.8 +/- 2.6% (P < 0.01) and pore diameter to 104 +/- 59 nm (P < 0.001). GFP-actin was expressed throughout the cells, whereas GFP-caveolin-1 had a punctate appearance; both responded to vascular endothelial growth factor by contraction toward the nucleus over hours in parallel with the formation of fenestrations. SK Hep1 cells resemble liver sinusoidal endothelial cells, and the vascular endothelial growth factor-induced formation of fenestration-like pores is preceded by contraction of actin cytoskeleton and attached caveolin-1 toward the nucleus.
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Affiliation(s)
- Victoria C. Cogger
- Centre for Education and Research on Ageing (CERA) and ANZAC Research Institute, Concord RG Hospital and University of Sydney, New South Wales, Australia; National Institute of Health and National Institute of Child Health and Human Development, Bethesda, Maryland; and Discovery Biology, Eskitis Institute for Cell & Molecular Therapies, Griffith University, Brisbane, Australia
| | - Irwin M. Arias
- Centre for Education and Research on Ageing (CERA) and ANZAC Research Institute, Concord RG Hospital and University of Sydney, New South Wales, Australia; National Institute of Health and National Institute of Child Health and Human Development, Bethesda, Maryland; and Discovery Biology, Eskitis Institute for Cell & Molecular Therapies, Griffith University, Brisbane, Australia
| | - Alessandra Warren
- Centre for Education and Research on Ageing (CERA) and ANZAC Research Institute, Concord RG Hospital and University of Sydney, New South Wales, Australia; National Institute of Health and National Institute of Child Health and Human Development, Bethesda, Maryland; and Discovery Biology, Eskitis Institute for Cell & Molecular Therapies, Griffith University, Brisbane, Australia
| | - Aisling C. McMahon
- Centre for Education and Research on Ageing (CERA) and ANZAC Research Institute, Concord RG Hospital and University of Sydney, New South Wales, Australia; National Institute of Health and National Institute of Child Health and Human Development, Bethesda, Maryland; and Discovery Biology, Eskitis Institute for Cell & Molecular Therapies, Griffith University, Brisbane, Australia
| | - Debra L. Kiss
- Centre for Education and Research on Ageing (CERA) and ANZAC Research Institute, Concord RG Hospital and University of Sydney, New South Wales, Australia; National Institute of Health and National Institute of Child Health and Human Development, Bethesda, Maryland; and Discovery Biology, Eskitis Institute for Cell & Molecular Therapies, Griffith University, Brisbane, Australia
| | - Vicky M. Avery
- Centre for Education and Research on Ageing (CERA) and ANZAC Research Institute, Concord RG Hospital and University of Sydney, New South Wales, Australia; National Institute of Health and National Institute of Child Health and Human Development, Bethesda, Maryland; and Discovery Biology, Eskitis Institute for Cell & Molecular Therapies, Griffith University, Brisbane, Australia
| | - David G. Le Couteur
- Centre for Education and Research on Ageing (CERA) and ANZAC Research Institute, Concord RG Hospital and University of Sydney, New South Wales, Australia; National Institute of Health and National Institute of Child Health and Human Development, Bethesda, Maryland; and Discovery Biology, Eskitis Institute for Cell & Molecular Therapies, Griffith University, Brisbane, Australia
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15
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Le Couteur DG, Warren A, Cogger VC, Smedsrød B, Sørensen KK, De Cabo R, Fraser R, McCuskey RS. Old age and the hepatic sinusoid. Anat Rec (Hoboken) 2008; 291:672-83. [PMID: 18484614 DOI: 10.1002/ar.20661] [Citation(s) in RCA: 112] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
Morphological changes in the hepatic sinusoid with old age are increasingly recognized. These include thickening and defenestration of the liver sinusoidal endothelial cell, sporadic deposition of collagen and basal lamina in the extracellular space of Disse, and increased numbers of fat engorged, nonactivated stellate cells. In addition, there is endothelial up-regulation of von Willebrand factor and ICAM-1 with reduced expression of caveolin-1. These changes have been termed age-related pseudocapillarization. The effects of old age on Kupffer cells are inconsistent, but impaired responsiveness is likely. There are functional implications of these aging changes in the hepatic sinusoid. There is reduced sinusoidal perfusion, which will impair the hepatic clearance of highly extracted substrates. Blood clearance of a variety of waste macromolecules takes place in liver sinusoidal endothelial cells (LSECs). Previous studies indicated either that aging had no effect, or reduced the endocytic capacity of LSECs. However, a recent study in mice showed reduced endocytosis in pericentral regions of the liver lobules. Reduced endocytosis may increase systemic exposure to potential harmful waste macromolecules such as advanced glycation end products Loss of fenestrations leads to impaired transfer of lipoproteins from blood to hepatocytes. This provides a mechanism for impaired chylomicron remnant clearance and postprandial hyperlipidemia associated with old age. Given the extensive range of substrates metabolized by the liver, age-related changes in the hepatic sinusoid and microcirculation have important systemic implications for aging and age-related diseases.
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Affiliation(s)
- David G Le Couteur
- Centre for Education and Research on Ageing, University of Sydney and Concord RG Hospital, Sydney, NSW, Australia.
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16
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Distribution of the alphaGal- and the non-alphaGal T-antigens in the pig kidney: potential targets for rejection in pig-to-man xenotransplantation. Immunol Cell Biol 2008; 86:363-71. [PMID: 18301385 DOI: 10.1038/icb.2008.1] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Carbohydrate antigens, present on pig vascular endothelial cells, seem to be the prime agents responsible for graft rejection, and although genetically modified animals that express less amounts of carbohydrate antigen are available, it is still useful to decide the localization of the reactive xenoantigens in organs contemplated for xenotransplantation. Here we compare the distribution in pig kidney of antigens important in xenograft destruction, namely the Galalpha1-3Gal (alphaGal) glycans, with the localization of the T-antigen (Galbeta1-3GalNAc). The alpha-galactose-specific lectin Griffonia simplicifolia isolectin 1B4 was used to detect the Galalpha1-3Gal glycans, whereas Arachis hypogaea (PNA) lectin and a monoclonal antibody (3C9) detected T-antigen. In addition, two vascular markers (anti-caveolin-1 and anti-von Willebrand factor) served to identify vascular structures of the kidney. Both conventional fluorescence and confocal microscopy were used to distinguish lectin and immunohistochemical staining. On the basis of fluorescence signals, the results indicate that the carbohydrate antigens are heterogeneously distributed in the pig kidney. alphaGal epitopes were sparse in the capillary loops forming the glomeruli and in the capillaries surrounding the convoluted tubules, but showed stronger staining in capillaries surrounding the limbs of Henle. In addition, the brush border and basement membranes of the convoluted tubules strongly reacted with the GS1-B4-lectin. Finally, the Galalpha1-3Gal glycans were also present on epithelial cells of the large collecting tubules. Regarding the T-antigen, PNA and 3C9 reacted with different glomerular cells, whereas both reacted strongly with the endothelial cells lining the large kidney vessels. Human serum incubation of pig kidney sections, in which the alphaGal epitopes were blocked by unconjugated GS1-B4, showed staining of the same vascular structures as were obtained after incubation with the T-antigen-detecting agents. The study thus proves a complex spatial distribution of carbohydrate antigens relevant for xenotransplantation of pig kidney.
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LE Couteur DG, Cogger VC, McCuskey RS, DE Cabo R, Smedsrød B, Sorensen KK, Warren A, Fraser R. Age-related changes in the liver sinusoidal endothelium: a mechanism for dyslipidemia. Ann N Y Acad Sci 2007; 1114:79-87. [PMID: 17804522 DOI: 10.1196/annals.1396.003] [Citation(s) in RCA: 44] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
The liver sinusoidal endothelial cell (LSEC) influences the transfer of substrates between the sinusoidal blood and hepatocytes and has a major role in endocytosis; therefore, changes in the LSEC have significant implications for hepatic function. There are major morphological changes in the LSEC in old age called pseudocapillarization. These changes include increased LSEC thickness and reduced numbers of pores in the LSEC, which are called fenestrations. Pseudocapillarization has been found in old humans, rats, mice, and nonhuman primates. In addition, old age is associated with impaired LSEC endocytosis and increased leukocyte adhesion, which contributes to reduced hepatic perfusion. Given that fenestrations in the endothelium allow passage of some lipoproteins, including chylomicron remnants, age-related reduction in fenestrations impairs hepatic lipoprotein metabolism. In old rats, caloric restriction was associated with complete preservation of LSEC morphology and fenestrations. In conclusion, pseudocapillarization of the LSEC is a newly discovered aging change that, through its effects on lipoproteins, contributes to the association between old age, dyslipidemia, and vascular disease.
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Affiliation(s)
- David G LE Couteur
- Centre for Education and Research on Ageing, University of Sydney and Concord RG Hospital, Sydney, NSW 2139, Australia.
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18
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Braet F. How molecular microscopy revealed new insights into the dynamics of hepatic endothelial fenestrae in the past decade. Liver Int 2004; 24:532-9. [PMID: 15566501 DOI: 10.1111/j.1478-3231.2004.0974.x] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
Abstract
This review discusses the current state of knowledge about the ultrastructure of hepatic endothelial fenestrae. The application of different high-resolution correlative microscopic methods during the past decade facilitated the accumulation of new insights in the morpho-functional and structural organization of the liver sieve. The data gathered unambiguously show the involvement of special domains in de novo formation and disappearance of fenestrae, and focuses future research into the (supra)molecular structure of the fenestrae-forming center, defenestration center and fenestrae-associated cytoskeleton ring by using cryo-electron microscopic tomography.
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Affiliation(s)
- Filip Braet
- Australian Key Centre for Microscopy and Microanalysis, Electron Microscope Unit, University of Sydney, Sydney, NSW 2006, Australia.
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Yokomori H, Oda M, Ogi M, Yoshimura K, Nomura M, Fujimaki K, Kamegaya Y, Tsukada N, Ishii H. Endothelin-1 suppresses plasma membrane Ca++-ATPase, concomitant with contraction of hepatic sinusoidal endothelial fenestrae. THE AMERICAN JOURNAL OF PATHOLOGY 2003; 162:557-66. [PMID: 12547713 PMCID: PMC1851144 DOI: 10.1016/s0002-9440(10)63849-7] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Accepted: 11/04/2002] [Indexed: 12/18/2022]
Abstract
Intracytoplasmic free calcium ions (Ca++) are maintained at a very low concentration in mammalian tissue by extruding Ca++ from the cytoplasm against a steep extracellular Ca++ concentration gradient, mainly through the activity of plasma membrane Ca++ pump-ATPase. The present study aimed to elucidate how endothelin-1 (ET-1) affects the morphology of sinusoidal endothelial fenestrae and ultrastructural distribution of plasma membrane ATPases and intracytoplasmic free Ca++ in isolated rat hepatic sinusoidal endothelial cells. Sinusoidal endothelial fenestrae were observed by scanning electron microscope. Ando's electron cytochemical method was used for ultrastructural localization of Ca++-Mg++-ATPase activity, electron immunogold postembedding method for Ca++ pump-ATPase immunoactivity, and antimonate method for intracytoplasmic free Ca++. Addition of ET-1 to sinusoidal endothelial cells significantly decreased Ca++-Mg++-ATPase activity and Ca++ pump-ATPase expression and increased intracytoplasmic free Ca++ concentration, concomitant with a decrease in diameter of sinusoidal endothelial fenestrae. Co-treatment with Bosentan abolished the actions of ET-1. These results suggest that ET-1 suppresses Ca++-Mg++-ATPase activity and Ca++ pump-ATPase expression on the plasma membrane of sinusoidal endothelial fenestrae, thereby attenuating the extrusion of intracytoplasmic free Ca++ into the extracellular space, leading to an increased concentration of intracytoplasmic free calcium ions and contraction of sinusoidal endothelial fenestrae.
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Affiliation(s)
- Hiroaki Yokomori
- Department of Internal Medicine and the Laboratory of Pathology, Kitasato Medical Center Hospital, Saitama.
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20
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Harada H, Pavlick KP, Hines IN, Lefer DJ, Hoffman JM, Bharwani S, Wolf RE, Grisham MB. Sexual dimorphism in reduced-size liver ischemia and reperfusion injury in mice: role of endothelial cell nitric oxide synthase. Proc Natl Acad Sci U S A 2003; 100:739-44. [PMID: 12522262 PMCID: PMC141066 DOI: 10.1073/pnas.0235680100] [Citation(s) in RCA: 42] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
We have recently reported that female mice are protected to a much greater extent from the injurious effects of reduced-size liver ischemia and reperfusion (RSL+I/R) than are males by an estrogen-dependent mechanism. The objective of this study was to examine the possibility that the protective effect observed in female mice depends on the up-regulation and/or activation of endothelial cell NO synthase (eNOS). Anesthetized female and male wild-type or eNOS-deficient C57BL/6 mice were subjected to 70% liver ischemia for 45 min followed by resection of the remaining 30% nonischemic lobes and reperfusion of ischemic tissue. Survival was monitored daily, whereas liver injury was quantified by using serum alanine aminotransferase determinations and histopathology. Hepatic eNOS mRNA, protein, and enzymatic activity were determined in male and female mice subjected to RSL+I/R. We found that liver injury was reduced and survival increased in female mice compared with males. This protective effect correlated with significant increases in hepatic eNOS message levels and enzyme activity but not protein expression compared with males subjected to the surgery. Furthermore, N(omega)-nitro-L-arginine methyl ester-treated or eNOS-deficient female mice responded to RSL+I/R with dramatic increases in liver injury and 100% mortality within 2 days of surgery. Finally, we found that pravastatin pretreatment significantly attenuated hepatocellular injury and increased survival of male mice, which was associated with enhanced expression of eNOS message. We conclude that the protective effect afforded female mice is due to the activation of hepatic eNOS activity and enhanced NO production.
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Affiliation(s)
- Hirohisa Harada
- Department of Molecular and Cellular Physiology, Louisiana State University Health Sciences Center, 1501 Kings Highway, Shreveport, LA 71130, USA
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Leifeld L, Fielenbach M, Dumoulin FL, Speidel N, Sauerbruch T, Spengler U. Inducible nitric oxide synthase (iNOS) and endothelial nitric oxide synthase (eNOS) expression in fulminant hepatic failure. J Hepatol 2002; 37:613-9. [PMID: 12399227 DOI: 10.1016/s0168-8278(02)00271-4] [Citation(s) in RCA: 44] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
BACKGROUND/AIMS Inducible nitric oxide synthase (iNOS) and endothelial nitric oxide synthase (eNOS) have important functions in inflammation and vasoregulation but their role in fulminant hepatic failure (FHF) is not well understood. METHODS Intrahepatic in situ staining and semi-quantification of iNOS and eNOS by immunohistochemistry in 25 patients with FHF, in 40 patients with chronic liver diseases (CLD) and in ten normal controls (NC). RESULTS Expression patterns of iNOS and eNOS differed. While in NC only faint iNOS expression was found in some Kupffer cells/macrophages and hepatocytes, eNOS was expressed constitutively in sinusoidal and vascular endothelial cells. In CLD, iNOS expression was induced in Kupffer cells/macrophages and hepatocytes, representing the main iNOS expressing cell types. Additionally, bile ducts, vascular endothelial cells and lymphocytes also expressed iNOS (P = 0.001). In contrast, no differences were found between eNOS expression in CLD and NC (P = 0.64). The same cell types expressed eNOS and iNOS in FHF but numbers of both were significantly enhanced, exceeding the levels seen in CLD (P < 0.001, P = 0.017). CONCLUSIONS Our data demonstrate that iNOS and eNOS are differently regulated in physiologic conditions and in liver disease. While eNOS seems to be involved in the physiological regulation of hepatic perfusion, strong upregulation of iNOS might contribute to inflammatory processes in FHF.
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Affiliation(s)
- Ludger Leifeld
- Department of Internal Medicine I, University of Bonn, Sigmund Freud Strasse 25, D-53105 Bonn, Germany.
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Goligorsky MS, Li H, Brodsky S, Chen J. Relationships between caveolae and eNOS: everything in proximity and the proximity of everything. Am J Physiol Renal Physiol 2002; 283:F1-10. [PMID: 12060581 DOI: 10.1152/ajprenal.00377.2001] [Citation(s) in RCA: 91] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
Caveolae, flask-shaped invaginations of the plasma membrane occupying up to 30% of cell surface in capillaries, represent a predominant location of endothelial nitric oxide synthase (eNOS) in endothelial cells. The caveolar coat protein caveolin forms high-molecular-weight, Triton-insoluble complexes through oligomerization mediated by interactions between NH2-terminal residues 61-101. eNOS is targeted to caveolae by cotranslational N-myristoylation and posttranslational palmitoylation. Caveolin-1 coimmunoprecipitates with eNOS; interaction with eNOS occurs via the caveolin-1 scaffolding domain and appears to result in the inhibition of NOS activity. The inhibitory conformation of eNOS is reversed by the addition of excess Ca2+/calmodulin and by Akt-induced phosphorylation of eNOS. Here, we shall dissect the system using the classic paradigm of a reflex loop: 1) the action of afferent elements, such as fluid shear stress and its putative caveolar sensor, on caveolae; 2) the ways in which afferent signals may affect the central element, the activation of the eNOS-nitric oxide system; and 3) several resultant well-established and novel physiologically important effector mechanisms, i.e., vasorelaxation, angiogenesis, membrane fluidity, endothelial permeability, deterrance of inflammatory cells, and prevention of platelet aggregation.
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Affiliation(s)
- Michael S Goligorsky
- Department of Medicine, State University of New York at Stony Brook, Stony Brook, New York 11794-8152, USA.
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Braet F, Spector I, Shochet N, Crews P, Higa T, Menu E, de Zanger R, Wisse E. The new anti-actin agent dihydrohalichondramide reveals fenestrae-forming centers in hepatic endothelial cells. BMC Cell Biol 2002; 3:7. [PMID: 11914125 PMCID: PMC101387 DOI: 10.1186/1471-2121-3-7] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2001] [Accepted: 03/21/2002] [Indexed: 01/05/2023] Open
Abstract
BACKGROUND Liver sinusoidal endothelial cells (LSECs) react to different anti-actin agents by increasing their number of fenestrae. A new structure related to fenestrae formation could be observed when LSECs were treated with misakinolide. In this study, we investigated the effects of two new actin-binding agents on fenestrae dynamics. High-resolution microscopy, including immunocytochemistry and a combination of fluorescence- and scanning electron microscopy was applied. RESULTS Halichondramide and dihydrohalichondramide disrupt microfilaments within 10 minutes and double the number of fenestrae in 30 minutes. Dihydrohalichondramide induces fenestrae-forming centers, whereas halichondramide only revealed fenestrae-forming centers without attached rows of fenestrae with increasing diameter. Correlative microscopy showed the absence of actin filaments (F-actin) in sieve plates and fenestrae-forming centers. Comparable experiments on umbilical vein endothelial cells and bone marrow sinusoidal endothelial cells revealed cell contraction without the appearance of fenestrae or fenestrae-forming centers. CONCLUSION (I) A comparison of all anti-actin agents tested so far, revealed that the only activity that misakinolide and dihydrohalichondramide have in common is their barbed end capping activity; (II) this activity seems to slow down the process of fenestrae formation to such extent that it becomes possible to resolve fenestrae-forming centers; (III) fenestrae formation resulting from microfilament disruption is probably unique to LSECs.
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Affiliation(s)
- Filip Braet
- Laboratory for Cell Biology and Histology, Free University of Brussels (VUB), Laarbeeklaan 103, 1090 Brussels-Jette, Belgium
| | - Ilan Spector
- Department of Physiology and Biophysics, Health Science Center, State University of New York at Stony Brook (SUNY), Stony Brook, NY 11794-8661, New York, USA
| | - Nava Shochet
- Department of Physiology and Biophysics, Health Science Center, State University of New York at Stony Brook (SUNY), Stony Brook, NY 11794-8661, New York, USA
| | - Phillip Crews
- Department of Chemistry and Biochemistry, University of California, Santa Cruz, CA 9506, USA
| | - Tatsuo Higa
- Department of Marine Sciences, University of the Ryukyus, Nishihara, Okinawa 903-01, Japan
| | - Eline Menu
- Department of Hematology and Immunology, Free University of Brussels (VUB), Laarbeeklaan 103, 1090 Brussels-Jette, Belgium
| | - Ronald de Zanger
- Laboratory for Cell Biology and Histology, Free University of Brussels (VUB), Laarbeeklaan 103, 1090 Brussels-Jette, Belgium
| | - Eddie Wisse
- Laboratory for Cell Biology and Histology, Free University of Brussels (VUB), Laarbeeklaan 103, 1090 Brussels-Jette, Belgium
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