Scavenger-receptor-mediated endocytosis in endocardial endothelial cells of Atlantic cod Gadus morhua.

1998 ◽  
Vol 201 (11) ◽  
pp. 1707-1718 ◽  
Author(s):  
K K Sørensen ◽  
J Melkko ◽  
B Smedsrød
Keyword(s):  
Endothelial Cells ◽  
Gadus Morhua ◽  
Atlantic Cod ◽  
Scavenger Receptor ◽  
Scavenger Receptors ◽  
Type I ◽  
Receptor Ligands ◽  
Endocardial Endothelial Cells ◽  
Scavenger Receptor Ligands

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.

scholarly journals New Scavenger Receptor-Like Receptors for the Binding of Lipopolysaccharide to Liver Endothelial and Kupffer Cells

1998 ◽  
Vol 66 (11) ◽  
pp. 5107-5112 ◽  
Author(s):  
Marijke van Oosten ◽  
Erika van de Bilt ◽  
Theo J. C. van Berkel ◽  
Johan Kuiper
Keyword(s):  
Endothelial Cells ◽  
Kupffer Cells ◽  
Binding Sites ◽  
Oxidized Ldl ◽  
Scavenger Receptor ◽  
Scavenger Receptors ◽  
Liver Endothelial Cells ◽  
Parenchymal Cells

ABSTRACT Lipopolysaccharide (LPS) is cleared from the blood mainly by the liver. The Kupffer cells are primarily responsible for this clearance; liver endothelial and parenchymal cells contribute to a lesser extent. Although several binding sites have been described, only CD14 is known to be involved in LPS signalling. Among the other LPS binding sites that have been identified are scavenger receptors. Scavenger receptor class A (SR-A) types I and II are expressed in the liver on endothelial cells and Kupffer cells, and a 95-kDa receptor, identified as macrosialin, is expressed on Kupffer cells. In this study, we examined the role of scavenger receptors in the binding of LPS by the liver in vivo and in vitro. Fucoidin, a scavenger receptor ligand, significantly reduced the clearance of 125I-LPS from the serum and decreased the liver uptake of 125I-LPS about 40%. Within the liver, the in vivo binding of 125I-LPS to Kupffer and liver endothelial cells was decreased 72 and 71%, respectively, while the binding of 125I-LPS to liver parenchymal cells increased 34% upon fucoidin preinjection. Poly(I) inhibited the binding of 125I-LPS to Kupffer and endothelial cells in vitro 73 and 78%, respectively, while poly(A) had no effect. LPS inhibited the binding of acetylated low-density lipoprotein (acLDL) to Kupffer and liver endothelial cells 40 and 55%, respectively, and the binding of oxidized LDL (oxLDL) to Kupffer and liver endothelial cells 65 and 61%, respectively. oxLDL and acLDL did not significantly inhibit the binding of LPS to these cells. We conclude that on both endothelial cells and Kupffer cells, LPS binds mainly to scavenger receptors, but SR-A and macrosialin contribute to a limited extent to the binding of LPS.

Identification of Scavenger Receptor Sr-Bi in The Endothelial Cells and the Smooth Muscle Cells of Rat Aorta in Vitro and in Vivo

2000 ◽  
Vol 6 (S2) ◽  
pp. 484-485
Author(s):  
Y P. Liu ◽  
Y. C. Yeh ◽  
V. C. Yang
Keyword(s):  
Endothelial Cells ◽  
Smooth Muscle ◽  
Smooth Muscle Cells ◽  
Scavenger Receptor ◽  
Muscle Cells ◽  
Rat Aorta ◽  
Cell Surface Receptor ◽  
Type I

The class B, type I scavenger receptor (SR-BI) was the first molecularly well defined cell surface receptor which binds HDL and mediates the selective uptake of HDL cholesteryl ester. It is expressed primarily in liver and steroidogenic tissues. However, the recent studies also suggested a potentially important role of SR-BI in the initial steps of cholesterol efflux in the peripheral tissues. In this study, we have used immunofluorescence and immunoelectron microscopy to study the expression and subcellular localization of SR-BI in the endothelial cells and the smooth muscle cells of rat aorta in vitro and in vivo.

Specific endocytosis and catabolism in the scavenger endothelial cells of cod (Gadus morhua L.) generate high-energy metabolites

2001 ◽  
Vol 204 (9) ◽  
pp. 1537-1546
Author(s):  
T. Seternes ◽  
I. Oynebraten ◽  
K. Sorensen ◽  
B. Smedsrod
Keyword(s):  
Endothelial Cells ◽  
High Performance ◽  
Gadus Morhua ◽  
Atlantic Cod ◽  
Degradation Products ◽  
Chondroitin Sulphate ◽  
Scavenger Receptor ◽  
High Performance Liquid Chromatographic ◽  
High Energy ◽  
Heart Atrium

The catabolic fate of circulating hyaluronan and the proteoglycan chondroitin sulphate (CSPG) was studied in the Atlantic cod (Gadus morhua L.). Distribution studies using radio-iodinated ligand demonstrated that CSPG was rapidly eliminated from the blood by the endocardial endothelial cells (EECs) of the heart atrium and ventricle. The presence of excess amounts of hyaluronan or CSPG inhibited uptake of [125I]hyaluronan into cultured atrial EECs (aEECs) by 46% and 84%, respectively. Neither formaldehyde-treated serum albumin (FSA) nor mannose inhibited this uptake. The presence of excess amounts of CSPG and hyaluronan inhibited uptake of [125I]CSPG by 90% and 42%, respectively, suggesting that aEECs express a specific hyaluronan binding site that also recognizes CSPG. FSA inhibited endocytosis of [1251]CSPG by 65%, indicating that CSPG is also recognized by the scavenger receptor. Approximately 17% and 57% of added [125I]hyaluronan and 15% and 65% of the added [125I]CSPG were endocytosed after 1 and 24h, respectively. High-performance liquid chromatographic analyses of the spent medium after endocytosis of hyaluronan and CSPG serglycin labelled biosynthetically with 3H in the acetyl groups identified labelled the low-molecular-mass degradation products as [3H]acetate, indicating that aEECs operate anaerobically. These findings suggest that acetate released from cod EECs following catabolism of endocytosed hyaluronan and CSPG represents a high-energy metabolite that may fuel cardiomyocytes.

Fc receptor mediated endocytosis of small soluble immunoglobulin G immune complexes in Kupffer and endothelial cells from rat liver

2000 ◽  
Vol 113 (18) ◽  
pp. 3255-3266
Author(s):  
T. Lovdal ◽  
E. Andersen ◽  
A. Brech ◽  
T. Berg
Keyword(s):  
Endothelial Cells ◽  
Kupffer Cells ◽  
Immune Complexes ◽  
Scavenger Receptor ◽  
Mannose Receptor ◽  
Endocytic Pathway ◽  
Scavenger Receptors ◽  
Receptor Ligands ◽  
Receptor Ligand ◽  
Liver Endothelial Cells

Soluble circulating immunoglobulin G immune complexes are mainly eliminated by the liver, predominantly by uptake in the Kupffer cells, but also the liver endothelial cells seem to be of importance. In the present study we have followed the intracellular turnover of immune complexes after Fc(gamma) receptor mediated endocytosis in cultured rat liver endothelial cells and Kupffer cells by means of isopycnic centrifugation, DAB cross-linking and morphological techniques. For the biochemical experiments the antigen, dinitrophenylated bovine serum albumin (BSA), was labeled with radioiodinated tyramine cellobiose that cannot cross biological membranes and therefore traps labeled degradation products at the site of formation. The endocytic pathway followed by immune complexes was compared with that followed by scavenger receptor ligands, such as formaldehyde treated BSA and dinitrophenylated BSA, and the mannose receptor ligand ovalbumin. Both Kupffer cells and liver endothelial cells took up and degraded the immune complexes, but there was a clear delay in the degradation of immune complexes as compared to degradation of ligands taken up via scavenger receptors. The kinetics of the endocytosis of scavenger receptor ligand was unaffected by simultaneous uptake of immune complexes. Experiments using both biochemical and morphological techniques indicated that the delayed degradation was due to a late arrival of the immune complexes at the lysosomes, which partly was explained by retroendocytosis of immune complexes. Electron microscopy studies revealed that the immune complexes were retained in the early endosomes that remained accessible to other endocytic markers such as ovalbumin. In addition, the immune complexes were seen in multivesicular compartments apparently devoid of other endocytic markers. Finally, the immune complexes were degraded in the same lysosomes as the ligands of scavenger receptors. Thus, immune complexes seem to follow an endocytic pathway that is kinetically or maybe morphologically different from that followed by scavenger and mannose receptor ligands.

Abstract 418: Co-Culture of Endothelial Cells, Smooth Muscle Cells and Monocytes in Collagen Scaffold: A Novel i n vitro Model of Atherosclerosis

2017 ◽  
Vol 37 (suppl_1) ◽  
Author(s):  
Martin Liu ◽  
Angelos Karagiannis ◽  
Matthew Sis ◽  
Srivatsan Kidambi ◽  
Yiannis Chatzizisis
Keyword(s):  
Endothelial Cells ◽  
Smooth Muscle ◽  
Smooth Muscle Cells ◽  
Type I Collagen ◽  
Smooth Muscle Actin ◽  
Muscle Cells ◽  
Type I ◽  
Collagen Gels ◽  
Human Coronary Artery

Objectives: To develop and validate a 3D in-vitro model of atherosclerosis that enables direct interaction between various cell types and/or extracellular matrix. Methods and Results: Type I collagen (0.75 mg/mL) was mixed with human artery smooth muscle cells (SMCs; 6x10 5 cells/mL), medium, and water. Human coronary artery endothelial cells (HCAECs; 10 5 /cm 2 ) were plated on top of the collagen gels and activated with oxidized low density lipoprotein cholesterol (LDL-C). Monocytes (THP-1 cells; 10 5 /cm 2 ) were then added on top of the HCAECs. Immunofluorescence showed the expression of VE-cadherin by HCAECs (A, B) and α-smooth muscle actin by SMCs (A). Green-labelled LDL-C particles were accumulated in the subendothelial space, as well as in the cytoplasm of HCAECs and SMCs (C). Activated monocytes were attached to HCAECs and found in the subendothelial area (G-I). Both HCAECs and SMCs released IL-1β, IL-6, IL-8, PDGF-BB, TGF-ß1, and VEGF. Scanning and transmission electron microscopy showed the HCAECs monolayer forming gap junctions and the SMCs (D-F) and transmigrating monocytes within the collagen matrix (G-I). Conclusions: In this work, we presented a novel, easily reproducible and functional in-vitro experimental model of atherosclerosis that has the potential to enable in-vitro sophisticated molecular and drug development studies.

Disparate cytokine regulation of ICAM-1 in rat alveolar epithelial cells and pulmonary endothelial cells in vitro

1995 ◽  
Vol 269 (1) ◽  
pp. L127-L135 ◽  
Author(s):  
W. W. Barton ◽  
S. Wilcoxen ◽  
P. J. Christensen ◽  
R. Paine
Keyword(s):  
Endothelial Cells ◽  
Epithelial Cells ◽  
Inflammatory Cytokines ◽  
Alveolar Epithelial Cells ◽  
Normal Lung ◽  
Type I ◽  
Type Ii Cells ◽  
Type Ii ◽  
Alveolar Epithelial

Intercellular adhesion molecule-1 (ICAM-1) is expressed at high levels on type I alveolar epithelial cells in the normal lung and is induced in vitro as type II cells spread in primary culture. In contrast, in most nonhematopoetic cells ICAM-1 expression is induced in response to inflammatory cytokines. We have formed the hypothesis that the signals that control ICAM-1 expression in alveolar epithelial cells are fundamentally different from those controlling expression in most other cells. To test this hypothesis, we have investigated the influence of inflammatory cytokines on ICAM-1 expression in isolated type II cells that have spread in culture and compared this response to that of rat pulmonary artery endothelial cells (RPAEC). ICAM-1 protein, determined both by a cell-based enzyme-linked immunosorbent assay and by Western blot analysis, and mRNA were minimally expressed in unstimulated RPAEC but were significantly induced in a time- and dose-dependent manner by treatment with tumor necrosis factor-alpha, interleukin-1 beta, or interferon-gamma. In contrast, these cytokines did not influence the constitutive high level ICAM-1 protein expression in alveolar epithelial cells and only minimally affected steady-state mRNA levels. ICAM-1 mRNA half-life, measured in the presence of actinomycin D, was relatively long at 7 h in alveolar epithelial cells and 4 h in RPAEC. The striking lack of response of ICAM-1 expression by alveolar epithelial cells to inflammatory cytokines is in contrast to virtually all other epithelial cells studied to date and supports the hypothesis that ICAM-1 expression by these cells is a function of cellular differentiation.(ABSTRACT TRUNCATED AT 250 WORDS)

Abstract 16: BcrKinase is a Novel Akt Kinase That Modulates Scavenger Receptor BI- and PDZK1-dependent Actions of HDL in Endothelium

2016 ◽  
Vol 36 (suppl_1) ◽  
Author(s):  
Anastasia Sacharidou ◽  
Wan-Ru Lee ◽  
Philip E Shaul ◽  
Chieko Mineo
Keyword(s):  
Endothelial Cells ◽  
Endothelial Cell ◽  
Kinase Activity ◽  
Scavenger Receptor ◽  
Adaptor Protein ◽  
Myelogenous Leukemia ◽  
Endothelial Cell Migration ◽  
Kinase Assay ◽  
Type I ◽  
Akt Kinase

High density lipoprotein cholesterol (HDL) has direct atheroprotective actions on endothelium. These are mediated by scavenger receptor class B, type I (SR-BI) and its adaptor protein PDZK1, and they entail the activation of Akt kinase, which phosphorylates and thereby stimulates endothelial nitric oxide synthase (eNOS). In the present work we sought to determine how PDZK1 couples HDL/SR-BI to Akt and eNOS to modulate endothelial function. Using tandem affinity purification (TAP) following the infection of the human endothelial cell line EAhy926 with adenovirus expressing TAP-tagged PDZK1, we identified Breakpoint Cluster Region (Bcr) kinase as a PDZK1 interacting protein in endothelium. Whereas Bcr is well-known as a component of the Bcr-Abl fusion protein that results from translocation of the Philadelphia chromosome in chronic myelogenous leukemia, little is known of its function in endothelial cells. Bcr contains several distinctive domains including a C-terminal PDZ binding motif and a serine/threonine protein kinase domain. In primary human aortic endothelial cells (HAEC), we determined that endogenous Bcr interacts with PDZK1 in an HDL-dependent manner, and that Bcr is required for HDL-induced activation of eNOS and HDL stimulation of endothelial cell migration, which underlies the ability of the lipoprotein to promote endothelial monolayer integrity. Studies of mutant forms of Bcr with disruption of PDZK1 binding or kinase activity introduced into endothelial cells further revealed that Bcr-PDZK1 interaction and its kinase function are required for HDL activation of Akt and eNOS. Using a novel kinase assay that we recently developed that employs time-resolved Forster resonance energy transfer, we found that via SR-BI and PDZK1, HDL stimulates Bcr kinase activity in endothelial cells more than 20-fold. In addition, using Akt-based peptides in studies of the two known kinases for Akt, mTOR and PDK1, we determined that HDL activates Bcr kinase to directly phosphorylate Akt-Ser473 in an mTOR independent manner, and that Akt-Thr308 is a direct substrate of PDK1. These collective findings have identified Bcr to be a novel kinase for Akt, and they have revealed that Bcr is critically involved in HDL modulation of endothelial cell phenotype.

Abstract 624: Endothelial Scavenger Receptor Class B, Type I (SR-BI) Mediates LDL Uptake by the Artery Wall and Promotes Atherosclerosis in Hypercholesterolemic Mice

2016 ◽  
Vol 36 (suppl_1) ◽  
Author(s):  
Linzhang Huang ◽  
Ken Chambliss ◽  
Mohamed Ahmed ◽  
Chieko Mineo ◽  
Philip W Shaul
Keyword(s):  
Endothelial Cells ◽  
Scavenger Receptor ◽  
Plasma Lipid ◽  
Density Lipoprotein ◽  
Type I ◽  
Artery Wall ◽  
Blocking Antibody ◽  
Scavenger Receptor Class ◽  
Class B ◽  
Ldl Uptake

In endothelial cells, high density lipoprotein cholesterol (HDL) binding to scavenger receptor class B, type I (SR-BI) promotes the production of the antiatherogenic signaling molecule nitric oxide (NO) and also endothelial repair. To study how SR-BI in endothelium impacts atherosclerosis, we bred newly-created floxed SR-BI mice, vascular endothelial cadherin promoter-driven Cre recombinase transgenic (VECad-Cre), and apoE -/- mice to generate apoE -/- with normal endothelial SR-BI expression (SR-BI ECIN ;apoE -/- ) or selective deletion of SR-BI from endothelium (SR-BI ECOUT ;apoE -/- ). At weaning all mice were placed on an atherogenic diet (20% fat, 1.25% cholesterol), and plasma lipid profiles and atherosclerosis were evaluated 8 weeks later. Endothelial deletion of SR-BI did not alter the plasma lipid profile. Surprisingly, male SR-BI ECOUT ;apoE -/- mice displayed 63% less atherosclerosis in the en face aorta than male SR-BI ECIN ;apoE -/- mice, aortic root lesions were comparably affected, and similar findings were obtained in females. Recognizing that SR-BI binds both HDL and low density lipoprotein cholesterol (LDL), to then discern how endothelial SR-BI promotes atherosclerosis we determined using Di-I-labeled oxidized LDL (oxLDL) if SR-BI influences oxLDL uptake by endothelial cells. Such uptake is the first step in the endothelial transcytosis that delivers LDL to the artery wall to initiate atherogenesis. OxLDL uptake by primary human aortic endothelial cells was blunted by 87% by SR-BI blocking antibody, and it was also decreased by SR-BI deletion via siRNA, and by the chemical inhibitor of SR-BI BLT-1. Furthermore, SR-BI blocking antibody and BLT-1 caused marked declines in endothelial oxLDL transcytosis. Moreover, 4 hours following IV administration, oxLDL uptake in aorta was decreased by 84% in SR-BI ECOUT ;apoE -/- versus SR-BI ECIN ;apoE -/- mice. These collective findings indicate that endothelial SR-BI plays an important role in atherogenesis, and that it likely does so by mediating LDL uptake into the artery wall. They further suggest that there are mechanisms that govern LDL transport across endothelium that may be targeted to provide novel means to combat atherosclerosis.

scholarly journals Uvaol Improves the Functioning of Fibroblasts and Endothelial Cells and Accelerates the Healing of Cutaneous Wounds in Mice

Molecules ◽  
2020 ◽  
Vol 25 (21) ◽  
pp. 4982
Author(s):  
Julianderson Carmo ◽  
Polliane Cavalcante-Araújo ◽  
Juliane Silva ◽  
Jamylle Ferro ◽  
Ana Carolina Correia ◽  
...  
Keyword(s):  
Endothelial Cells ◽  
Healing Process ◽  
Virgin Olive Oil ◽  
Mapk Signaling ◽  
Control Treatment ◽  
Type I ◽  
Pentacyclic Triterpene ◽  
Cutaneous Wounds ◽  
Positive Effects

Uvaol is a natural pentacyclic triterpene that is widely found in olives and virgin olive oil, exerting various pharmacological properties. However, information remains limited about how it affects fibroblasts and endothelial cells in events associated with wound healing. Here, we report the effect of uvaol in the in vitro and in vivo healing process. We show the positive effects of uvaol on migration of fibroblasts and endothelial cells in the scratch assay. Protein synthesis of fibronectin and laminin (but not collagen type I) was improved in uvaol-treated fibroblasts. In comparison, tube formation by endothelial cells was enhanced after uvaol treatment. Mechanistically, the effects of uvaol on cell migration involved the PKA and p38-MAPK signaling pathway in endothelial cells but not in fibroblasts. Thus, the uvaol-induced migratory response was dependent on the PKA pathway. Finally, topical treatment with uvaol caused wounds to close faster than in the control treatment using experimental cutaneous wounds model in mice. In conclusion, uvaol positively affects the behavior of fibroblasts and endothelial cells, potentially promoting cutaneous healing.

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