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Sánchez Romano J, Simón-Santamaría J, McCourt P, Smedsrød B, Mortensen KE, Sagona AP, Sørensen KK, Larsen AK. Liver sinusoidal cells eliminate blood-borne phage K1F. mSphere 2024; 9:e0070223. [PMID: 38415633 PMCID: PMC10964407 DOI: 10.1128/msphere.00702-23] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2023] [Accepted: 01/30/2024] [Indexed: 02/29/2024] Open
Abstract
Phage treatment has regained attention due to an increase in multiresistant bacteria. For phage therapy to be successful, phages must reach their target bacteria in sufficiently high numbers. Blood-borne phages are believed to be captured by macrophages in the liver and spleen. Since liver sinusoids also consist of specialized scavenger liver sinusoidal endothelial cells (LSECs) and Kupffer cells (KCs), this study investigated the contribution of both cell types in the elimination of Escherichia coli phage K1Fg10b::gfp (K1Fgfp) in mice. Circulatory half-life, organ, and hepatocellular distribution of K1Fgfp were determined following intravenous administration. Internalization of K1Fgfp and effects of phage opsonization on uptake were explored using primary mouse and human LSEC and KC cultures. When inoculated with 107 virions, >95% of the total K1Fgfp load was eliminated from the blood within 20 min, and 94% of the total retrieved K1Fgfp was localized to the liver. Higher doses resulted in slower elimination, possibly reflecting temporary saturation of liver scavenging capacity. Phage DNA was detected in both cell types, with a KC:LSEC ratio of 12:1 per population following cell isolation. Opsonization with plasma proteins increased time-dependent cellular uptake in both LSECs and KCs in vitro. Internalized phages were rapidly transported along the endocytic pathway to lysosomal compartments. Reduced viability of intracellular K1Fgfp corroborated inactivation following endocytosis. This study is the first to identify phage distribution in the liver at the hepatocellular level, confirming clearance of K1Fgfp performed mostly by KCs with a significant uptake also in LSECs.IMPORTANCEFaced with the increasing amounts of bacteria with multidrug antimicrobial resistance, phage therapy has regained attention as a possible treatment option. The phage field has recently experienced an emergence in commercial interest as research has identified new and more efficient ways of identifying and matching phages against resistant superbugs. Currently, phages are unapproved drugs in most parts of the world. For phages to reach broad clinical use, they must be shown to be clinically safe and useful. The results presented herein contribute to increased knowledge about the pharmacokinetics of the T7-like phage K1F in the mammalian system. The cell types of the liver that are responsible for rapid phage blood clearance are identified. Our results highlight the need for more research about appropriate dose regimens when phage therapy is delivered intravenously and advise essential knowledge about cell systems that should be investigated further for detailed phage pharmacodynamics.
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Affiliation(s)
| | | | - Peter McCourt
- Department of Medical Biology, UiT The Arctic University of Norway, Tromsø, Norway
| | - Bård Smedsrød
- Department of Medical Biology, UiT The Arctic University of Norway, Tromsø, Norway
| | - Kim Erlend Mortensen
- Gastrointestinal Surgery Unit, University Hospital of North Norway, Tromsø, Norway
| | - Antonia P. Sagona
- School of Life Sciences, University of Warwick, Coventry, United Kingdom
| | | | - Anett Kristin Larsen
- Department of Medical Biology, UiT The Arctic University of Norway, Tromsø, Norway
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Kyrrestad I, Larsen AK, Sánchez Romano J, Simón-Santamaría J, Li R, Sørensen KK. Infection of liver sinusoidal endothelial cells with Muromegalovirus muridbeta1 involves binding to neuropilin-1 and is dynamin-dependent. Front Cell Infect Microbiol 2023; 13:1249894. [PMID: 38029264 PMCID: PMC10665495 DOI: 10.3389/fcimb.2023.1249894] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2023] [Accepted: 10/23/2023] [Indexed: 12/01/2023] Open
Abstract
Liver sinusoidal endothelial cells (LSEC) are scavenger cells with a remarkably high capacity for clearance of several blood-borne macromolecules and nanoparticles, including some viruses. Endocytosis in LSEC is mainly via the clathrin-coated pit mediated route, which is dynamin-dependent. LSEC can also be a site of infection and latency of betaherpesvirus, but mode of virus entry into these cells has not yet been described. In this study we have investigated the role of dynamin in the early stage of muromegalovirus muridbeta1 (MuHV-1, murid betaherpesvirus 1, murine cytomegalovirus) infection in mouse LSECs. LSEC cultures were freshly prepared from C57Bl/6JRj mouse liver. We first examined dose- and time-dependent effects of two dynamin-inhibitors, dynasore and MitMAB, on cell viability, morphology, and endocytosis of model ligands via different LSEC scavenger receptors to establish a protocol for dynamin-inhibition studies in these primary cells. LSECs were challenged with MuHV-1 (MOI 0.2) ± dynamin inhibitors for 1h, then without inhibitors and virus for 11h, and nuclear expression of MuHV-1 immediate early antigen (IE1) measured by immune fluorescence. MuHV-1 efficiently infected LSECs in vitro. Infection was significantly and independently inhibited by dynasore and MitMAB, which block dynamin function via different mechanisms, suggesting that initial steps of MuHV-1 infection is dynamin-dependent in LSECs. Infection was also reduced in the presence of monensin which inhibits acidification of endosomes. Furthermore, competitive binding studies with a neuropilin-1 antibody blocked LSEC infection. This suggests that MuHV-1 infection in mouse LSECs involves virus binding to neuropilin-1 and occurs via endocytosis.
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Affiliation(s)
- Ingelin Kyrrestad
- Department of Medical Biology, Faculty of Health Sciences, UiT - The Arctic University of Norway, Tromsø, Norway
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Antwi MB, Dumitriu G, Simón-Santamaria J, Romano JS, Li R, Smedsrød B, Vik A, Eskild W, Sørensen KK. Liver sinusoidal endothelial cells show reduced scavenger function and downregulation of Fc gamma receptor IIb, yet maintain a preserved fenestration in the Glmpgt/gt mouse model of slowly progressing liver fibrosis. PLoS One 2023; 18:e0293526. [PMID: 37910485 PMCID: PMC10619817 DOI: 10.1371/journal.pone.0293526] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2023] [Accepted: 10/16/2023] [Indexed: 11/03/2023] Open
Abstract
Liver sinusoidal endothelial cells (LSECs) are fenestrated endothelial cells with a unique, high endocytic clearance capacity for blood-borne waste macromolecules and colloids. This LSEC scavenger function has been insufficiently characterized in liver disease. The Glmpgt/gt mouse lacks expression of a subunit of the MFSD1/GLMP lysosomal membrane protein transporter complex, is born normal, but soon develops chronic, mild hepatocyte injury, leading to slowly progressing periportal liver fibrosis, and splenomegaly. This study examined how LSEC scavenger function and morphology are affected in the Glmpgt/gt model. FITC-labelled formaldehyde-treated serum albumin (FITC-FSA), a model ligand for LSEC scavenger receptors was administered intravenously into Glmpgt/gt mice, aged 4 months (peak of liver inflammation), 9-10 month, and age-matched Glmpwt/wt mice. Organs were harvested for light and electron microscopy, quantitative image analysis of ligand uptake, collagen accumulation, LSEC ultrastructure, and endocytosis receptor expression (also examined by qPCR and western blot). In both age groups, the Glmpgt/gt mice showed multifocal liver injury and fibrosis. The uptake of FITC-FSA in LSECs was significantly reduced in Glmpgt/gt compared to wild-type mice. Expression of LSEC receptors stabilin-1 (Stab1), and mannose receptor (Mcr1) was almost similar in liver of Glmpgt/gt mice and age-matched controls. At the same time, immunostaining revealed differences in the stabilin-1 expression pattern in sinusoids and accumulation of stabilin-1-positive macrophages in Glmpgt/gt liver. FcγRIIb (Fcgr2b), which mediates LSEC endocytosis of soluble immune complexes was widely and significantly downregulated in Glmpgt/gt liver. Despite increased collagen in space of Disse, LSECs of Glmpgt/gt mice showed well-preserved fenestrae organized in sieve plates but the frequency of holes >400 nm in diameter was increased, especially in areas with hepatocyte damage. In both genotypes, FITC-FSA also distributed to endothelial cells of spleen and bone marrow sinusoids, suggesting that these locations may function as possible compensatory sites of clearance of blood-borne scavenger receptor ligands in liver fibrosis.
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Affiliation(s)
- Milton Boaheng Antwi
- Department of Medical Biology, UiT-The Arctic University of Norway, Tromsø, Norway
- Section of Haematology, University Hospital of North Norway, Tromsø, Norway
| | - Gianina Dumitriu
- Department of Medical Biology, UiT-The Arctic University of Norway, Tromsø, Norway
| | | | | | - Ruomei Li
- Department of Medical Biology, UiT-The Arctic University of Norway, Tromsø, Norway
| | - Bård Smedsrød
- Department of Medical Biology, UiT-The Arctic University of Norway, Tromsø, Norway
| | - Anders Vik
- Section of Haematology, University Hospital of North Norway, Tromsø, Norway
- Department of Clinical Medicine, UiT-The Arctic University of Norway, Tromsø, Norway
| | - Winnie Eskild
- Department of Biosciences, University of Oslo, Oslo, Norway
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Li R, Bhandari S, Martinez-Zubiaurre I, Bruun JA, Urbarova I, Smedsrød B, Simón-Santamaría J, Sørensen KK. Changes in the proteome and secretome of rat liver sinusoidal endothelial cells during early primary culture and effects of dexamethasone. PLoS One 2022; 17:e0273843. [PMID: 36054185 PMCID: PMC9439253 DOI: 10.1371/journal.pone.0273843] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2021] [Accepted: 08/16/2022] [Indexed: 11/28/2022] Open
Abstract
Introduction Liver sinusoidal endothelial cells (LSECs) are specialized fenestrated scavenger endothelial cells involved in the elimination of modified plasma proteins and tissue turnover waste macromolecules from blood. LSECs also participate in liver immune responses. A challenge when studying LSEC biology is the rapid loss of the in vivo phenotype in culture. In this study, we have examined biological processes and pathways affected during early-stage primary culture of rat LSECs and checked for cell responses to the pro-inflammatory cytokine interleukin (IL)-1β and the anti-inflammatory drug dexamethasone. Methods LSECs from male Sprague Dawley rats were cultured on type I collagen in 5% oxygen atmosphere in DMEM with serum-free supplements for 2 and 24 h. Quantitative proteomics using tandem mass tag technology was used to examine proteins in cells and supernatants. Validation was done with qPCR, ELISA, multiplex immunoassay, and caspase 3/7 assay. Cell ultrastructure was examined by scanning electron microscopy, and scavenger function by quantitative endocytosis assays. Results LSECs cultured for 24 h showed a characteristic pro-inflammatory phenotype both in the presence and absence of IL-1β, with upregulation of cellular responses to cytokines and interferon-γ, cell-cell adhesion, and glycolysis, increased expression of fatty acid binding proteins (FABP4, FABP5), and downregulation of several membrane receptors (STAB1, STAB2, LYVE1, CLEC4G) and proteins in pyruvate metabolism, citric acid cycle, fatty acid elongation, amino acid metabolism, and oxidation-reduction processes. Dexamethasone inhibited apoptosis and improved LSEC viability in culture, repressed inflammatory and immune regulatory pathways and secretion of IL-1β and IL-6, and further upregulated FABP4 and FABP5 compared to time-matched controls. The LSEC porosity and endocytic activity were reduced at 24 h both with and without dexamethasone but the dexamethasone-treated cells showed a less stressed phenotype. Conclusion Rat LSECs become activated towards a pro-inflammatory phenotype during early culture. Dexamethasone represses LSEC activation, inhibits apoptosis, and improves cell viability.
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Affiliation(s)
- Ruomei Li
- Department of Medical Biology, UiT–The Arctic University of Norway, Tromsø, Norway
| | - Sabin Bhandari
- Department of Medical Biology, UiT–The Arctic University of Norway, Tromsø, Norway
| | | | - Jack-Ansgar Bruun
- Department of Medical Biology, UiT–The Arctic University of Norway, Tromsø, Norway
| | - Ilona Urbarova
- Department of Community Medicine, UiT–The Arctic University of Norway, Tromsø, Norway
| | - Bård Smedsrød
- Department of Medical Biology, UiT–The Arctic University of Norway, Tromsø, Norway
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Larsen AK, Simón-Santamaría J, Elvevold K, Ericzon BG, Mortensen KE, McCourt P, Smedsrød B, Sørensen KK. Autofluorescence in freshly isolated adult human liver sinusoidal cells. Eur J Histochem 2021; 65. [PMID: 34897295 PMCID: PMC8696389 DOI: 10.4081/ejh.2021.3337] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2021] [Accepted: 12/01/2021] [Indexed: 11/23/2022] Open
Abstract
Autofluorescent granules of various sizes were observed in primary human liver endothelial cells (LSECs) upon laser irradiation using a wide range of wavelengths. Autofluorescence was detected in LAMP-1 positive vesicles, suggesting lysosomal location. Confocal imaging of freshly prepared cultures and imaging flow cytometry of non-cultured cells revealed fluorescence in all channels used. Treatment with a lipofuscin autofluorescence quencher reduced autofluorescence, most efficiently in the near UV-area. These results, combined with the knowledge of the very active blood clearance function of LSECs support the notion that lysosomally located autofluorescent material reflected accumulation of lipofuscin in the intact liver. These results illustrate the importance of careful selection of fluorophores, especially when labelling of live cells where the quencher is not compatible.
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Affiliation(s)
| | | | - Kjetil Elvevold
- Department of Medical Biology, UiT - The Arctic University of Norway, Tromsø.
| | - Bo Göran Ericzon
- Department of Clinical Science, Intervention and Technology (CLINTEC), Karolinska University Hospital, Stockholm.
| | | | - Peter McCourt
- Department of Medical Biology, UiT - The Arctic University of Norway, Tromsø.
| | - Bård Smedsrød
- Department of Medical Biology, UiT - The Arctic University of Norway, Tromsø.
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Bhandari S, Larsen AK, McCourt P, Smedsrød B, Sørensen KK. The Scavenger Function of Liver Sinusoidal Endothelial Cells in Health and Disease. Front Physiol 2021; 12:757469. [PMID: 34707514 PMCID: PMC8542980 DOI: 10.3389/fphys.2021.757469] [Citation(s) in RCA: 43] [Impact Index Per Article: 14.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2021] [Accepted: 09/14/2021] [Indexed: 12/12/2022] Open
Abstract
The aim of this review is to give an outline of the blood clearance function of the liver sinusoidal endothelial cells (LSECs) in health and disease. Lining the hundreds of millions of hepatic sinusoids in the human liver the LSECs are perfectly located to survey the constituents of the blood. These cells are equipped with high-affinity receptors and an intracellular vesicle transport apparatus, enabling a remarkably efficient machinery for removal of large molecules and nanoparticles from the blood, thus contributing importantly to maintain blood and tissue homeostasis. We describe here central aspects of LSEC signature receptors that enable the cells to recognize and internalize blood-borne waste macromolecules at great speed and high capacity. Notably, this blood clearance system is a silent process, in the sense that it usually neither requires or elicits cell activation or immune responses. Most of our knowledge about LSECs arises from studies in animals, of which mouse and rat make up the great majority, and some species differences relevant for extrapolating from animal models to human are discussed. In the last part of the review, we discuss comparative aspects of the LSEC scavenger functions and specialized scavenger endothelial cells (SECs) in other vascular beds and in different vertebrate classes. In conclusion, the activity of LSECs and other SECs prevent exposure of a great number of waste products to the immune system, and molecules with noxious biological activities are effectively “silenced” by the rapid clearance in LSECs. An undesired consequence of this avid scavenging system is unwanted uptake of nanomedicines and biologics in the cells. As the development of this new generation of therapeutics evolves, there will be a sharp increase in the need to understand the clearance function of LSECs in health and disease. There is still a significant knowledge gap in how the LSEC clearance function is affected in liver disease.
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Affiliation(s)
- Sabin Bhandari
- Vascular Biology Research Group, Department of Medical Biology, University of Tromsø (UiT) - The Arctic University of Norway, Tromsø, Norway
| | - Anett Kristin Larsen
- Vascular Biology Research Group, Department of Medical Biology, University of Tromsø (UiT) - The Arctic University of Norway, Tromsø, Norway
| | - Peter McCourt
- Vascular Biology Research Group, Department of Medical Biology, University of Tromsø (UiT) - The Arctic University of Norway, Tromsø, Norway
| | - Bård Smedsrød
- Vascular Biology Research Group, Department of Medical Biology, University of Tromsø (UiT) - The Arctic University of Norway, Tromsø, Norway
| | - Karen Kristine Sørensen
- Vascular Biology Research Group, Department of Medical Biology, University of Tromsø (UiT) - The Arctic University of Norway, Tromsø, Norway
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Bhandari S, Li R, Simón-Santamaría J, McCourt P, Johansen SD, Smedsrød B, Martinez-Zubiaurre I, Sørensen KK. Transcriptome and proteome profiling reveal complementary scavenger and immune features of rat liver sinusoidal endothelial cells and liver macrophages. BMC Mol Cell Biol 2020; 21:85. [PMID: 33246411 PMCID: PMC7694354 DOI: 10.1186/s12860-020-00331-9] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2020] [Accepted: 11/18/2020] [Indexed: 12/15/2022] Open
Abstract
BACKGROUND Liver sinusoidal endothelial cells (LSECs) and Kupffer cells (KCs; liver resident macrophages) form the body's most effective scavenger cell system for the removal of harmful blood-borne substances, ranging from modified self-proteins to pathogens and xenobiotics. Controversies in the literature regarding the LSEC phenotype pose a challenge when determining distinct functionalities of KCs and LSECs. This may be due to overlapping functions of the two cells, insufficient purification and/or identification of the cells, rapid dedifferentiation of LSECs in vitro, or species differences. We therefore characterized and quantitatively compared expressed gene products of freshly isolated, highly pure LSECs (fenestrated SE-1/FcγRIIb2+) and KCs (CD11b/c+) from Sprague Dawley, Crl:CD (SD), male rats using high throughput mRNA-sequencing and label-free proteomics. RESULTS We observed a robust correlation between the proteomes and transcriptomes of the two cell types. Integrative analysis of the global molecular profile demonstrated the immunological aspects of LSECs. The constitutive expression of several immune genes and corresponding proteins of LSECs bore some resemblance with the expression in macrophages. LSECs and KCs both expressed high levels of scavenger receptors (SR) and C-type lectins. Equivalent expression of SR-A1 (Msr1), mannose receptor (Mrc1), SR-B1 (Scarb1), and SR-B3 (Scarb2) suggested functional similarity between the two cell types, while functional distinction between the cells was evidenced by LSEC-specific expression of the SRs stabilin-1 (Stab1) and stabilin-2 (Stab2), and the C-type lectins LSECtin (Clec4g) and DC-SIGNR (Clec4m). Many immune regulatory factors were differentially expressed in LSECs and KCs, with one cell predominantly expressing a specific cytokine/chemokine and the other cell the cognate receptor, illustrating the complex cytokine milieu of the sinusoids. Both cells expressed genes and proteins involved in antigen processing and presentation, and lymphocyte co-stimulation. CONCLUSIONS Our findings support complementary and partly overlapping scavenging and immune functions of LSECs and KCs. This highlights the importance of including LSECs in studies of liver immunity, and liver clearance and toxicity of large molecule drugs and nano-formulations.
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Affiliation(s)
- Sabin Bhandari
- Department of Medical Biology, Vascular Biology Research Group, University of Tromsø (UiT) -The Arctic University of Norway, Hansine Hansens veg 18, N-9037, Tromsø, Norway
| | - Ruomei Li
- Department of Medical Biology, Vascular Biology Research Group, University of Tromsø (UiT) -The Arctic University of Norway, Hansine Hansens veg 18, N-9037, Tromsø, Norway
| | - Jaione Simón-Santamaría
- Department of Medical Biology, Vascular Biology Research Group, University of Tromsø (UiT) -The Arctic University of Norway, Hansine Hansens veg 18, N-9037, Tromsø, Norway
| | - Peter McCourt
- Department of Medical Biology, Vascular Biology Research Group, University of Tromsø (UiT) -The Arctic University of Norway, Hansine Hansens veg 18, N-9037, Tromsø, Norway
| | - Steinar Daae Johansen
- Department of Medical Biology, Vascular Biology Research Group, University of Tromsø (UiT) -The Arctic University of Norway, Hansine Hansens veg 18, N-9037, Tromsø, Norway.,Faculty of Biosciences and Aquaculture, Nord University, Bodø, Norway
| | - Bård Smedsrød
- Department of Medical Biology, Vascular Biology Research Group, University of Tromsø (UiT) -The Arctic University of Norway, Hansine Hansens veg 18, N-9037, Tromsø, Norway.
| | | | - Karen Kristine Sørensen
- Department of Medical Biology, Vascular Biology Research Group, University of Tromsø (UiT) -The Arctic University of Norway, Hansine Hansens veg 18, N-9037, Tromsø, Norway
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Tryland M, Romano JS, Marcin N, Nymo IH, Josefsen TD, Sørensen KK, Mørk T. Cervid herpesvirus 2 and not Moraxella bovoculi caused keratoconjunctivitis in experimentally inoculated semi-domesticated Eurasian tundra reindeer. Acta Vet Scand 2017; 59:23. [PMID: 28438213 PMCID: PMC5404682 DOI: 10.1186/s13028-017-0291-2] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2017] [Accepted: 04/19/2017] [Indexed: 11/11/2022] Open
Abstract
Background Infectious keratoconjunctivitis (IKC) is a transmissible disease in semi-domesticated Eurasian reindeer (Rangifer tarandus tarandus). It is regarded as multifactorial and a single causative pathogen has not yet been identified. From clinical outbreaks we have previously identified Cervid herpesvirus 2 (CvHV2) and Moraxella bovoculi as candidates for experimental investigations. Eighteen reindeer were inoculated in the right eye with CvHV2 (n = 5), M. bovoculi (n = 5), CvHV2 and M. bovoculi (n = 5) or sterile saline water (n = 3; controls). Results All animals inoculated with CvHv2, alone or in combination with M. bovoculi, showed raised body temperature, increased lacrimation, conjunctivitis, excretion of pus and periorbital oedema; clinical signs that increased in severity from day 2 post inoculation (p.i.) and throughout the experiment, until euthanasia 5–7 days p.i. Examination after euthanasia revealed corneal oedema, and three animals displayed a corneal ulcer. CvHV2 could be identified in swab samples from both the inoculated eye and the control eye from most animals and time points, indicating a viral spread from the inoculation site. Conclusions This study showed that CvHV2 alone and in combination with M. bovoculi was able to cause the characteristic clinical signs of IKC in reindeer, whereas inoculation of M. bovoculi alone, originally isolated from a reindeer with IKC, did not produce clinical signs. Previous studies have suggested that herding procedures, animal stress and subsequent reactivation of latent CvHV2 infection in older animals is a plausible mechanism for IKC outbreaks among reindeer calves and young animals in reindeer herds. However, further studies are needed to fully understand the infection biology and epidemiology associated with IKC in reindeer.
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Simon-Santamaria J, Rinaldo CH, Kardas P, Li R, Malovic I, Elvevold K, McCourt P, Smedsrød B, Hirsch HH, Sørensen KK. Efficient uptake of blood-borne BK and JC polyomavirus-like particles in endothelial cells of liver sinusoids and renal vasa recta. PLoS One 2014; 9:e111762. [PMID: 25375646 PMCID: PMC4222947 DOI: 10.1371/journal.pone.0111762] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2014] [Accepted: 09/30/2014] [Indexed: 12/18/2022] Open
Abstract
Liver sinusoidal endothelial cells (LSECs) are specialized scavenger cells that mediate high-capacity clearance of soluble waste macromolecules and colloid material, including blood-borne adenovirus. To explore if LSECs function as a sink for other viruses in blood, we studied the fate of virus-like particles (VLPs) of two ubiquitous human DNA viruses, BK and JC polyomavirus, in mice. Like complete virions, VLPs specifically bind to receptors and enter cells, but unlike complete virions, they cannot replicate. 125I-labeled VLPs were used to assess blood decay, organ-, and hepatocellular distribution of ligand, and non-labeled VLPs to examine cellular uptake by immunohisto- and -cytochemistry. BK- and JC-VLPs rapidly distributed to liver, with lesser uptake in kidney and spleen. Liver uptake was predominantly in LSECs. Blood half-life (∼1 min), and tissue distribution of JC-VLPs and two JC-VLP-mutants (L55F and S269F) that lack sialic acid binding affinity, were similar, indicating involvement of non-sialic acid receptors in cellular uptake. Liver uptake was not mediated by scavenger receptors. In spleen, the VLPs localized to the red pulp marginal zone reticuloendothelium, and in kidney to the endothelial lining of vasa recta segments, and the transitional epithelium of renal pelvis. Most VLP-positive vessels in renal medulla did not express PV-1/Meca 32, suggesting location to the non-fenestrated part of vasa recta. The endothelial cells of these vessels also efficiently endocytosed a scavenger receptor ligand, formaldehyde-denatured albumin, suggesting high endocytic activity compared to other renal endothelia. We conclude that LSECs very effectively cleared a large fraction of blood-borne BK- and JC-VLPs, indicating a central role of these cells in early removal of polyomavirus from the circulation. In addition, we report the novel finding that a subpopulation of endothelial cells in kidney, the main organ of polyomavirus persistence, showed selective and rapid uptake of VLPs, suggesting a role in viremic organ tropism.
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Affiliation(s)
| | - Christine Hanssen Rinaldo
- Department of Microbiology and Infection Control, University Hospital of North Norway, Tromsø, Norway
- Department of Clinical Medicine, UiT - The Arctic University of Norway, Tromsø, Norway
| | - Piotr Kardas
- Department of Biomedicine, University of Basel, Basel, Switzerland
| | - Ruomei Li
- Department of Medical Biology, UiT – The Arctic University of Norway, Tromsø, Norway
| | - Ivana Malovic
- Department of Medical Biology, UiT – The Arctic University of Norway, Tromsø, Norway
| | - Kjetil Elvevold
- Department of Medical Biology, UiT – The Arctic University of Norway, Tromsø, Norway
| | - Peter McCourt
- Department of Medical Biology, UiT – The Arctic University of Norway, Tromsø, Norway
| | - Bård Smedsrød
- Department of Medical Biology, UiT – The Arctic University of Norway, Tromsø, Norway
| | - Hans H. Hirsch
- Department of Biomedicine, University of Basel, Basel, Switzerland
- Divisions of Infectious Diseases and Hospital Epidemiology, University Hospital of Basel, Basel, Switzerland
| | - Karen Kristine Sørensen
- Department of Medical Biology, UiT – The Arctic University of Norway, Tromsø, Norway
- * E-mail:
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Svistounov D, Oteiza A, Zykova SN, Sørensen KK, McCourt P, McLachlan AJ, McCuskey RS, Smedsrød B. Hepatic disposal of advanced glycation end products during maturation and aging. Exp Gerontol 2013; 48:549-56. [PMID: 23531498 DOI: 10.1016/j.exger.2013.03.005] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2012] [Revised: 02/06/2013] [Accepted: 03/16/2013] [Indexed: 01/10/2023]
Abstract
UNLABELLED Aging is characterized by progressive loss of metabolic and biochemical functions and accumulation of metabolic by-products, including advanced glycation end products (AGEs), which are observed in several pathological conditions. A number of waste macromolecules, including AGEs are taken up from the circulation by endocytosis mainly into liver sinusoidal endothelial cells (LSECs) and Kupffer cells (KCs). However, AGEs still accumulate in different tissues with aging, despite the presence of this clearance mechanism. The aim of the present study was to determine whether the efficiency of LSECs and KCs for disposal of AGEs changes through aging. RESULTS After intravenous administration of (14)C-AGE-albumin in pre-pubertal, young adult, middle aged and old mice, more than 90% of total recovered (14)C-AGE was liver associated, irrespective of age. LSECs and KCs represented the main site of uptake. A fraction of the (14)C-AGE degradation products ((14)C-AGE-DPs) was stored for months in the lysosomes of these cells after uptake. The overall rate of elimination of (14)C-AGE-DPs from the liver was markedly faster in pre-pubertal than in all post-pubertal age groups. The ability to eliminate (14)C-AGE-DPs decreased to similar extents after puberty in LSECs and KCs. A rapid early removal phase was characteristic for all age groups except the old group, where this phase was absent. CONCLUSIONS Removal of AGE-DPs from the liver scavenger cells is a very slow process that changes with age. The ability of these cells to dispose of AGEs declines after puberty. Decreased AGE removal efficiency early in life may lead to AGE accumulation.
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Affiliation(s)
- Dmitri Svistounov
- Department of Medical Biology, University of Tromsø, Tromsø, Norway.
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12
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Sørensen KK, McCourt P, Berg T, Crossley C, Le Couteur D, Wake K, Smedsrød B. The scavenger endothelial cell: a new player in homeostasis and immunity. Am J Physiol Regul Integr Comp Physiol 2012; 303:R1217-30. [PMID: 23076875 DOI: 10.1152/ajpregu.00686.2011] [Citation(s) in RCA: 141] [Impact Index Per Article: 11.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
Abstract
To maintain homeostasis, the animal body is equipped with a powerful system to remove circulating waste. This review presents evidence that the scavenger endothelial cell (SEC) is responsible for the clearance of blood-borne waste macromolecules in vertebrates. SECs express pattern-recognition endocytosis receptors (mannose and scavenger receptors), and in mammals, the endocytic Fc gamma-receptor IIb2. This cell type has an endocytic machinery capable of super-efficient uptake and degradation of physiological and foreign waste material, including all major classes of biological macromolecules. In terrestrial vertebrates, most SECs line the wall of the liver sinusoid. In phylogenetically older vertebrates, SECs reside instead in heart, kidney, or gills. SECs, thus, by virtue of their efficient nonphagocytic elimination of physiological and microbial substances, play a critical role in the innate immunity of vertebrates. In major invertebrate phyla, including insects, the same function is carried out by nephrocytes. The concept of a dual-cell principle of waste clearance is introduced to emphasize that professional phagocytes (macrophages in vertebrates; hemocytes in invertebrates) eliminate larger particles (>0.5 μm) by phagocytosis, whereas soluble macromolecules and smaller particles are eliminated efficiently and preferentially by clathrin-mediated endocytosis in nonphagocytic SECs in vertebrates or nephrocytes in invertebrates. Including these cells as important players in immunology and physiology provides an additional basis for understanding host defense and tissue homeostasis.
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Affiliation(s)
- Karen Kristine Sørensen
- Vascular Biology Research Group, Department of Medical Biology, Faculty of Health Sciences, University of Tromsø, Tromsø, Norway
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Oteiza A, Li R, McCuskey RS, Smedsrød B, Sørensen KK. Effects of oxidized low-density lipoproteins on the hepatic microvasculature. Am J Physiol Gastrointest Liver Physiol 2011; 301:G684-93. [PMID: 21778464 DOI: 10.1152/ajpgi.00347.2010] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
Oxidized low-density lipoproteins (oxLDLs) are involved in proinflammatory and cytotoxic events in different microcirculatory systems. The liver is an important scavenger organ for circulating oxLDLs. However, the interaction of oxLDL with the hepatic microcirculation has been poorly investigated. The present study was conducted to examine the effects of differently modified oxLDLs on the hepatic microvasculature. C57Bl/6J mice were injected intravenously with low-density lipoprotein (LDL), or LDL oxidized for 3 h (oxLDL(3)) or 24 h (oxLDL(24)), at doses resembling oxLDL plasma levels in cardiovascular disease patients. Radioiodinated ligands were used to measure blood decay and organ distribution, and nonlabeled ligands to evaluate microcirculatory responses, examined by in vivo microscopy 30-60 min after ligand injection, immunohistochemistry, and scanning and transmission electron microscopy. Mildly oxLDL (oxLDL(3)) was cleared from blood at a markedly slower rate than heavily oxLDL (oxLDL(24)), but significantly faster than LDL (P < 0.01). Injected oxLDLs distributed to liver. OxLDL effects were most pronounced in central areas of the liver lobules where oxLDL(3) elicited a significant (P < 0.05) reduction in perfused sinusoids, and both oxLDL(3) and oxLDL(24) significantly increased the numbers of swollen endothelial cells and adherent leukocytes compared with LDL (P < 0.05). OxLDL-treated livers also exhibited increased intercellular adhesion molecule (ICAM)-1 centrilobular staining. Electron microscopy showed a 30% increased thickness of the liver sinusoidal endothelium in the oxLDL(3) group (P < 0.05) and a reduced sinusoidal fenestration in centrilobular areas with increased oxidation of LDL (P for linear trend <0.05). In conclusion, OxLDL induced several acute changes in the liver microvasculature, which may lead to sinusoidal endothelial dysfunction.
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Affiliation(s)
- Ana Oteiza
- Vascular Biology Research Group, Dept. of Medical Biology, Univ. of Tromsø, Norway.
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Sørensen KK, Gregersen VR, Christensen OF, Velander IH, Bendixen C. Genomic regions associated with ventro-cranial chronic pleuritis in pig. J Anim Breed Genet 2011; 128:314-8. [PMID: 21749478 DOI: 10.1111/j.1439-0388.2010.00914.x] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
Ventro-cranial chronic pleuritis can be a result of pleuropneumonia and enzootic pneumonia. These diseases cause severe losses in intensive pig production worldwide, but host resistance is difficult to breed for. It could be beneficial to use marker-assisted selection, and a step towards this is to identify genomic regions associated with the trait. For this purpose, 7304 pigs from 11 boar families were analysed for associations between single nucleotide polymorphisms and ventro-cranial chronic pleuritis. The pigs were genotyped by the use of the iSelect Custom 7 K porcine SNP Chip. Quantitative trait loci (QTL), significant at the chromosome-wide level, were identified on Sus scrofa chromosomes (SSC) 2, 4, 11, 12 and 13 in four different boar families. The QTL on SSC 4 in family G was also significant at the genome-wide threshold according to Bonferroni correction. We have identified a number of candidate genes, but the causative mutations still need to be identified. Markers closely associated with the resistance traits have a strong potential for use in breeding towards animals with improved characteristics concerning ventro-cranial chronic pleuritis.
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Affiliation(s)
- K K Sørensen
- Department of Genetics and Biotechnology, Faculty of Agricultural Sciences, Aarhus University, Tjele, Denmark
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Li R, McCourt P, Schledzewski K, Goerdt S, Moldenhauer G, Liu X, Smedsrød B, Sørensen KK. Endocytosis of advanced glycation end-products in bovine choriocapillaris endothelial cells. Microcirculation 2011; 16:640-55. [PMID: 19657967 DOI: 10.1080/10739680903133185] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
Abstract
OBJECTIVES Age-related changes in Bruch's membrane (BM), situated between the retina and the choroid, include the accumulation of advanced glycation end-products (AGEs) and other modified macromolecules. An important clearance mechanism for such molecules is endocytosis via macrophages and specialized endothelial cells. This study examined the endocytic clearance of AGEs in choriocapillaris endothelial (CCE) cells, which are strategically located beneath the BM. MATERIALS AND METHODS Bovine CCE cultures were incubated with radiolabeled or fluorescently labeled AGE-modified bovine serum albumin (AGE-BSA). Cells and tissues were examined for the expression of two AGE-binding scavenger receptors, stabilin-1 and -2, by immunohistochemistry and Western blotting, and with antibody inhibition studies. RESULTS CCE cells effectively endocytosed AGE-BSA via a scavenger receptor-mediated pathway. A polyclonal antibody against stabilin-2 significantly inhibited endocytosis (40%). Tissue sections stained positive for stabilin-2 and -1 in the choriocapillaris layer, which was confirmed by immunoblots of cell extracts. Colocalization of stabilin-1 and -2 and internalized AGE-BSA was seen in early endosomes. CONCLUSIONS CCEs actively endocytose AGE-BSA and express the scavenger receptors, stabilin-1 and -2, of which at least stabilin-2 is involved in AGE-BSA uptake. Impairment of this stabilin-mediated clearance function may contribute to depositions of waste macromolecules in BM and subsequent retinopathy.
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Affiliation(s)
- Ruomei Li
- Department of Cell Biology and Histology, Institute of Medical Biology, University of Tromsø, Norway.
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Li R, Oteiza A, Sørensen KK, McCourt P, Olsen R, Smedsrød B, Svistounov D. Role of liver sinusoidal endothelial cells and stabilins in elimination of oxidized low-density lipoproteins. Am J Physiol Gastrointest Liver Physiol 2011; 300:G71-81. [PMID: 21030611 PMCID: PMC3025507 DOI: 10.1152/ajpgi.00215.2010] [Citation(s) in RCA: 83] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
Atherogenesis is associated with elevated levels of low-density lipoprotein (LDL) and its oxidized form (oxLDL) in the blood. The liver is an important scavenger organ for circulating oxLDLs. The present study aimed to examine endocytosis of mildly oxLDL (the major circulating form of oxLDLs) in liver sinusoidal endothelial cells (LSECs) and the involvement of the scavenger receptors stabilin-1 and stabilin-2 in this process. Freshly isolated LSECs, Kupffer cells (KCs), and stabilin-1- and stabilin-2-transfected human embryonic kidney cells were incubated with fluorescently labeled or radiolabeled oxLDLs [oxidized for 3 h (oxLDL(3)), 6 h, or 24 h (oxLDL(24))] to measure endocytosis. The intracellular localization of oxLDLs and stabilins in LSECs was examined by immunofluorescence and immunogold electron microscopy. Whereas oxLDL(24) was endocytosed both by LSECs and KCs, oxLDL(3) (mildly oxLDL) was taken up by LSECs only. The LSEC uptake of oxLDLs was significantly inhibited by the scavenger receptor ligand formaldehyde-treated serum albumin. Uptake of all modified LDLs was high in stabilin-1-transfected cells, whereas stabilin-2-transfected cells preferentially took up oxLDL(24), suggesting that stabilin-1 is a more important receptor for mildly oxLDLs than stabilin-2. Double immunogold labeling experiments in LSECs indicated interactions of stabilin-1 and stabilin-2 with oxLDL(3) on the cell surface, in coated pits, and endocytic vesicles. LSECs but not KCs endocytosed mildly oxLDL. Both stabilin-1 and stabilin-2 were involved in the LSEC endocytosis of oxLDLs, but experiments with stabilin-transfected cells pointed to stabilin-1 as the most important receptor for mildly oxLDL.
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Affiliation(s)
- Ruomei Li
- Faculty of Health Sciences, 1Vascular Biology Research Group and
| | - Ana Oteiza
- Faculty of Health Sciences, 1Vascular Biology Research Group and
| | | | - Peter McCourt
- Faculty of Health Sciences, 1Vascular Biology Research Group and
| | - Randi Olsen
- 2Department of Electron Microscopy, Institute of Medical Biology, University of Tromsø, Tromsø, Norway
| | - Bård Smedsrød
- Faculty of Health Sciences, 1Vascular Biology Research Group and
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Simon-Santamaria J, Malovic I, Warren A, Oteiza A, Le Couteur D, Smedsrød B, McCourt P, Sørensen KK. Age-related changes in scavenger receptor-mediated endocytosis in rat liver sinusoidal endothelial cells. J Gerontol A Biol Sci Med Sci 2010; 65:951-60. [PMID: 20576648 DOI: 10.1093/gerona/glq108] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
Liver sinusoidal endothelial cells (LSECs) play an essential role in systemic waste clearance by effective endocytosis of blood-borne waste macromolecules. We aimed to study LSECs' scavenger function during aging, and whether age-related morphological changes (eg, defenestration) affect this function, in F344/BN F1 rats. Endocytosis of the scavenger receptor ligand formaldehyde-treated serum albumin was significantly reduced in LSECs from old rats. Ligand degradation, LSEC protein expression of the major scavenger receptors for formaldehyde-treated serum albumin endocytosis, stabilin-1 and stabilin-2, and their staining patterns along liver sinusoids, was similar at young and old age, suggesting that other parts of the endocytic machinery are affected by aging. Formaldehyde-treated serum albumin uptake per cell, and cell porosity evaluated by electron microscopy, was not correlated, indicating that LSEC defenestration is not linked to impaired endocytosis. We report a significantly reduced LSEC endocytic capacity at old age, which may be especially important in situations with increased circulatory waste loads.
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Elvevold K, Simon-Santamaria J, Hasvold H, McCourt P, Smedsrød B, Sørensen KK. Liver sinusoidal endothelial cells depend on mannose receptor-mediated recruitment of lysosomal enzymes for normal degradation capacity. Hepatology 2008; 48:2007-15. [PMID: 19026003 DOI: 10.1002/hep.22527] [Citation(s) in RCA: 60] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Abstract
UNLABELLED Liver sinusoidal endothelial cells (LSECs) are largely responsible for the removal of circulating lysosomal enzymes (LE) via mannose receptor (MR)-mediated endocytosis. We hypothesized that LSECs rely on this uptake to maintain their extraordinarily high degradation capacity for other endocytosed material. Circulatory half-life studies of (125)I-cathepsin-D in MR knockout (MR(-/-)) and wild-type mice, and endocytosis studies in LSEC cultures, showed a total dependence on the MR for effective clearance of cathepsin-D. Radioiodinated formaldehyde-treated serum albumin, a ligand for the LSEC scavenger receptors, was used to study catabolism of endocytosed material in MR(-/-) and wild-type mice. The plasma clearance, liver uptake, and the starting point for release of degradation products to blood, were similar in both experimental groups, indicating normal endocytosis and intracellular transport of scavenger receptor ligands in MR(-/-) mice. However, the rate of formaldehyde-treated serum albumin catabolism in the liver of the MR deficient animals was reduced to approximately 50% of wild-type values. A similar reduction in intracellular degradation was recorded in LSEC cultures from MR(-/-) mice compared to wild-type controls. In accordance with this, MR(-/-) LSECs had markedly and significantly reduced enzyme activities for four out of five LE tested, i.e., cathepsin-D, alpha-mannosidase, beta-hexosaminidase and arylsulfatase, but not acid phosphatase, compared to wild-type controls. Immunoblot analysis showed that the content of pro-cathepsin-D relative to total cathepsin-D in wild-type LSECs was less than one-fifth of that in hepatocytes, indicating lower endogenous LE production in the LSECs. CONCLUSION We show for the first time that LSEC depend on MR-mediated recruitment of LE from their surroundings for effective catabolism of endocytosed macromolecules.
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Affiliation(s)
- Kjetil Elvevold
- Department of Cell Biology and Histology, University of Tromsø, Tromsø, Norway
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Sørensen KK, Mørk T, Sigurdardóttir OG, Asbakk K, Akerstedt J, Bergsjø B, Fuglei E. Acute toxoplasmosis in three wild arctic foxes (Alopex lagopus) from Svalbard; one with co-infections of Salmonella Enteritidis PT1 and Yersinia pseudotuberculosis serotype 2b. Res Vet Sci 2005; 78:161-7. [PMID: 15563924 DOI: 10.1016/j.rvsc.2004.07.010] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 07/12/2004] [Indexed: 11/28/2022]
Abstract
Acute disseminated toxoplasmosis was diagnosed in three wild arctic foxes (Alopex lagopus) that were found dead in the same locality on Svalbard (Norway). The animals included one adult female and two 4-months-old pups. The adult fox was severely jaundiced. Necropsy revealed multifocal, acute, necrotizing hepatitis, acute interstitial pneumonia, and scattered foci of brain gliosis, often associated with Toxoplasma tachyzoites. One pup also had Toxoplasma-associated meningitis. In addition, the latter animal was infected with Yersinia pseudotuberculosis serotype 2b and Salmonella Enteritidis phage type 1 (PT1), which may have contributed to the severity of the Toxoplasma infection in this animal. The diagnosis of toxoplasmosis was confirmed by positive immunohistochemistry and detection of anti-Toxoplasma gondii antibodies in serum of all foxes. The animals were negative for Neospora caninum, canine distemper virus, canine adenovirus, and rabies virus on immunolabelling of tissue sections and smears.
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Affiliation(s)
- K K Sørensen
- National Veterinary Institute, Regional laboratory, NO-9292 Tromsø, Norway.
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Tryland M, Sørensen KK, Godfroid J. Prevalence of Brucella pinnipediae in healthy hooded seals (Cystophora cristata) from the North Atlantic Ocean and ringed seals (Phoca hispida) from Svalbard. Vet Microbiol 2004; 105:103-11. [PMID: 15627521 DOI: 10.1016/j.vetmic.2004.11.001] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2004] [Revised: 10/01/2004] [Accepted: 10/22/2004] [Indexed: 11/21/2022]
Abstract
Investigations for Brucella-infections were conducted in 29 hooded seals (Cystophora cristata) caught between Svalbard and Greenland (North Atlantic Ocean; Greenland Sea) autumn 2002, and from 20 ringed seals (Phoca hispida) caught in Billefjord, Svalbard, spring 2003. All animals were apparently healthy and were caught in their natural habitat. Bacteriology on tissue samples from ringed seals was negative, whereas Brucella sp. were recovered in tissues from 11 of the 29 hooded seals (38%), with the highest tissue prevalence in spleen (9/29) and lung lymph nodes (9/24). Anti-Brucella antibodies were detected in sera from 9 hooded seals (31%) (EDTA-modified Slow Agglutination test of Wright, Rose Bengal test, Complement Fixation Test, and Protein-A ELISA). The bacterial isolates all belonged to the genus Brucella according to classical biotyping and PCR analysis based on Insertion Sequence IS711, and were shown to be typical marine mammal strains, based on the occurrence of an IS711 element downstream of the bp26 gene. Their dependency on CO2 for growth, and the presence of one copy each of the omp2a and omp2b gene finally classified them as Brucella pinnipediae. Furthermore, all the hooded seal isolates showed an A+ M+ agglutination profile, which is different from the profile of reference seal strain 2/94 (harbour seal, Phoca vitulina). Thus, these results indicate that B. pinnipediae may contain different biovars. The present results suggest that infection with B. pinnipediae is enzootic in this population. Since the hooded seal is commercially hunted and consumed in Norway, the pathological impact of such infections and their zoonotic potential should be further addressed.
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Affiliation(s)
- Morten Tryland
- Section of Arctic Veterinary Medicine, Department of Food Safety and Infection Biology, The Norwegian School of Veterinary Science, P.O. Box 6204, NO-9292 Tromsø, Norway.
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Sørensen KK, Tollersrud OK, Evjen G, Smedsrød B. Mannose-receptor-mediated clearance of lysosomal alpha-mannosidase in scavenger endothelium of cod endocardium. Comp Biochem Physiol A Mol Integr Physiol 2001; 129:615-30. [PMID: 11423331 DOI: 10.1016/s1095-6433(01)00300-2] [Citation(s) in RCA: 21] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
Mannose-receptor-mediated clearance of circulating glycoproteins was studied in Atlantic cod (Gadus morhua). Distribution studies with radioiodinated and fluorescently labelled ligands showed that cod liver lysosomal alpha-mannosidase and yeast invertase were rapidly eliminated from blood via a mannose specific pathway in liver parenchymal cells and endocardial endothelial cells of atrium and ventricle. Asialo-orosomucoid, a galactose-terminated glycoprotein, was cleared by liver only. In vitro studies were performed with primary cultures of atrial-endocardial endothelial cells (AEC), incubated at 12 degrees C in a serum free medium. Cod AEC endocytosed mannose-terminated glycoproteins (125I-alpha-mannosidase, 125I-invertase, 125I-mannan, 125I-ovalbumin and unlabelled lysosomal alpha-mannosidase), whereas 125I-asialo-orosomucoid was not recognised. Uptake of radiolabelled mannose-terminated ligands was inhibited 80-100% in the presence of excess amounts of mannan, invertase, D-mannose, L-fucose or EGTA. Our results suggest that the cod endocardial endothelial cells express a specific Ca(2+)-dependent mannose receptor, analogous to the mannose receptor on mammalian macrophages and liver sinusoidal endothelial cells.
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Affiliation(s)
- K K Sørensen
- The Norwegian School of Veterinary Science, Department of Arctic Veterinary Medicine, Tromso, Norway
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Abstract
Scavenger receptors are multifunctional integral membrane proteins that mediate the endocytosis of many different macromolecular polyanions and also participate in host defence reactions and cell adherance. In Atlantic cod (Gadus morhua L.), two intravenously injected scavenger receptor ligands, [125I]tyramine-cellobiose-labelled formaldehyde-treated serum albumin (125I-TC-FSA) and 125I-labelled N-terminal propeptide of type I procollagen (125I-PINP), distributed mainly to the heart. Cellular uptake was visualized by injections of fluorescently labelled FSA (FITC-FSA), which was recovered in discrete vesicles in endocardial endothelial cells of both heart chambers. Studies in vitro showed that radioiodinated FSA and PINP were endocytosed and degraded very efficiently by cultured atrial endocardial endothelial cells. Moreover, uptake of 125I-FSA was Ca2+-independent. Out of a range of unlabelled ligands, only the scavenger receptor ligands FITC-FSA, polyinosinic acid and, to a varying extent, FSA, acetylated low-density lipoprotein (AcLDL) and PINP, were able to compete with radioiodinated FSA, PINP or AcLDL for uptake in isolated endocardial cells. From our findings, we conclude that the endocardial endothelial cells are major carriers of scavenger receptors in cod. In addition, our results strengthen the hypothesis that these cells in cod play the same important function as that established for the scavenger endothelial cells of the mammalian liver.
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Affiliation(s)
- K K Sørensen
- Department of Arctic Veterinary Medicine, Norwegian College of Veterinary Medicine, N-9005 Tromso, Norway
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Line PD, Sørensen KK, Kvernebo K. Postocclusive hyperaemia in skin measured in pigs by laser Doppler: influence of site of arterial stenosis in the limb. Eur J Surg 1996; 162:321-7. [PMID: 8739420] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
OBJECTIVE To investigate how site and severity of arterial stenosis, and distance between tourniquet and measuring probe influences the postocclusive hyperaemic response in limb skin recorded by laser Doppler. DESIGN Open study. MATERIAL Nine Norwegian Landrace pigs. INTERVENTION Experimental stenoses in the abdominal aorta, the external iliac and femoral arteries. The hyperaemic responses were recorded with the probe at two different distances from the tourniquet. MAIN OUTCOME MEASURES Curve pattern, relative reduction in flux between the two peaks in double humped curves, and time to peak hyperaemic flux. RESULTS Double humped curves were produced at all sites, but the blood pressure gradient required at the stenosis was greater the more proximal the stenosis. In distal stenoses there was a greater relative reduction in flux between the two peaks (p < 0.05). The time to peak hyperaemic flux was related to the gradient of the stenosis (mmHg) (r = 0.62, p < 0.0001), but was independent of its site. Increased distance between the tourniquet and the probe gave lower laser Doppler amplitudes and prolonged the time to peak hyperaemia in experiments with femoral artery stenosis (p < 0.05). CONCLUSION The hyperaemic response is governed by both the severity and the site of arterial stenosis. Stenoses distal to the tourniquet seem to impair the initial reperfusion more than comparable lesions proximal to the tourniquet. Time to reach peak hyperaemia is the single variable most closely related to the severity of the stenosis.
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Affiliation(s)
- P D Line
- Surgical Department, Aker Hospital, Oslo, Norway
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Line PD, Sørensen KK, Kvernebo K. Assessment of the physiological importance of iliac artery stenosis by laser Doppler flowmetry in pigs. Eur J Surg 1992; 158:281-6. [PMID: 1354493] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 03/25/2023]
Abstract
OBJECTIVE To test the hypothesis that a curve with two peak values (double hump) recorded by laser Doppler flowmetry over the skin of the lower limb during postocclusive hyperaemia reflects pathological vascular resistance in the aortoiliac segment. DESIGN Open study. MATERIAL Six Norwegian Landrace pigs. INTERVENTION Arterial stenoses were induced in the external iliac arteries. MAIN OUTCOME MEASURES Presence of double humped laser Doppler curves, relative decrease in laser Doppler flux between the two peaks, and time taken to reach peak hyperaemic flux. RESULTS Double humped curves were seen only when arterial stenoses were present. The relative decrease in laser Doppler flux between the two peaks, and the time to reach peak hyperaemic flux were related to the blood pressure gradient (mmHg) at the stenosis (r = 0.88 and 0.83, p less than 0.0001). The laser Doppler curve pattern can be explained by similar dynamic changes in arterial blood pressure distal to the tourniquet during hyperaemia. CONCLUSION These results confirm the hypothesis, and suggest that laser Doppler flowmetry recordings of postocclusive hyperaemia may be a non-invasive way of assessing the condition of the iliac artery.
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Affiliation(s)
- P D Line
- Department of Surgery, Aker Hospital, Oslo, Norway
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