Thranbospondin Promotes Cell-and Platelet-Substratum Adhesion

1987 ◽  
Author(s):  
George P Tuszynski ◽  
Vicki L Rothman ◽  
Andrew Murphy ◽  
Katherine Siegler ◽  
Linda Smith ◽  
...  
Keyword(s):  
Cell Adhesion ◽  
Cell Surface ◽  
Polyacrylamide Gel Electrophoresis ◽  
Cell Types ◽  
Preliminary Evidence ◽  
Human Platelets ◽  
Cell Surface Receptor ◽  
Binding Assays ◽  
Surface Receptor

Thrombospondin (TSP), isolated from human platelets, promotes the in vitro, calcium-specific adhesion of a variety of cells, including platelets, melanoma cells, muscle cells, endothelial cells, fibroblasts, and epithelial cells. The cell adhesion-promoting activity of TSP is species independent since human, bovine, pig, rat and mouse cells all adhered to TSP. Furthermore, the cell adhesion-promoting activity of TSP is specific and not due to a nonspecific protein effect or to contamination by fibronectin, vitronectin, or laminin. That is, neither bovine serum albumin nor TSP preparations treated with a monospecific anti-TSP antibody support cell adhesion. As analyzed by polyacrylamide-gel electrophoresis and specific antibody binding assays, the TSP preparations used in these studies contained no detectable fibronectin or laminin and less than 0.04% vitronectin. The cell surface receptor for TSP appears distinct frcm that of fibronectin since an antiserum that blocks cell adhesion to fibronectin has no effect on adhesion to TSP. In addition, The platelet cell surface receptor for TSP appears distinct, frcm that of fibrinogen since thrcmbasthenic platelets adhere to TSP as well as control platelets. Antibodies to the GPIIb-GPIIIa complex block platelet adhesion to fibrinogen but have no effect on adhesion to TSP. Initial characterization of the cell surface receptor for TSP shows it to be protein in nature since cells treated with trypsin fail to adhere to TSP. In summary, our results provide the first clear evidence that TSP specifically promotes cell-substratum adhesion of a variety of cell types independent of the animal species. Our preliminary evidence suggests that the cell-surface receptor(s) for TSP is protein and that it is distinct for the receptor for fibronectin and fibrinogen. Our data suggest that TSP may play a central role in normal adhesive events mediated by platelets and other cells, such as those involved in hemostasis and wound healing. In addition, TSP may be involved in pathological adhesive events mediated by platelets and tumor cells, such as those involved in cardiovascular disease and tumor cell metastasis.

scholarly journals ABD-Derived Protein Blockers of Human IL-17 Receptor A as Non-IgG Alternatives for Modulation of IL-17-Dependent Pro-Inflammatory Axis

2018 ◽  
Vol 19 (10) ◽  
pp. 3089 ◽  
Author(s):  
Marie Hlavničková ◽  
Milan Kuchař ◽  
Radim Osička ◽  
Lucie Vaňková ◽  
Hana Petroková ◽  
...  
Keyword(s):  
Cell Surface ◽  
Clinical Manifestations ◽  
Cell Surface Receptor ◽  
Enzyme Linked Immunosorbent Assay ◽  
Interleukin 17 ◽  
Normal Human Skin ◽  
High Affinity ◽  
Th 17 ◽  
Surface Receptor

Interleukin 17 (IL-17) and its cognate receptor A (IL-17RA) play a crucial role in Th17 cells-mediated pro-inflammatory pathway and pathogenesis of several autoimmune disorders including psoriasis. IL-17 is mainly produced by activated Th-17 helper cells upon stimulation by IL-23 and, via binding to its receptors, mediates IL-17-driven cell signaling in keratinocytes. Hyper-proliferation of keratinocytes belongs to major clinical manifestations in psoriasis. To modulate IL-17-mediated inflammatory cascade, we generated a unique collection of IL-17RA-targeting protein binders that prevent from binding of human IL-17A cytokine to its cell-surface receptor. To this goal, we used a highly complex combinatorial library derived from scaffold of albumin-binding domain (ABD) of streptococcal protein G, and ribosome display selection, to yield a collection of ABD-derived high-affinity ligands of human IL-17RA, called ARS binders. From 67 analyzed ABD variants, 7 different sequence families were identified. Representatives of these groups competed with human IL-17A for binding to recombinant IL-17RA receptor as well as to IL-17RA-Immunoglobulin G chimera, as tested in enzyme-linked immunosorbent assay (ELISA). Five ARS variants bound to IL-17RA-expressing THP-1 cells and blocked binding of human IL-17 cytokine to the cell surface, as tested by flow cytometry. Three variants exhibited high-affinity binding with a nanomolar Kd value to human keratinocyte HaCaT cells, as measured using Ligand Tracer Green Line. Upon IL-17-stimulated activation, ARS variants inhibited secretion of Gro-α (CXCL1) by normal human skin fibroblasts in vitro. Thus, we identified a novel class of inhibitory ligands that might serve as immunosuppressive IL-17RA-targeted non-IgG protein antagonists.

scholarly journals Isolation of an adhesion-mediating protein from chick neural retina adherons.

1985 ◽  
Vol 101 (3) ◽  
pp. 1071-1077 ◽  
Author(s):  
D Schubert ◽  
M LaCorbiere
Keyword(s):  
Cell Surface ◽  
Heparan Sulfate ◽  
Cultured Cells ◽  
Cell Types ◽  
Neural Retina ◽  
Cell Surface Receptor ◽  
Isolation And Characterization ◽  
Surface Receptor ◽  
Adhesive Interactions

Adherons are high molecular weight glycoprotein complexes which are released into the growth medium of cultured cells. They mediate the adhesive interactions of many cell types, including those of embryonic chick neural retina. The cell surface receptor for chick neural retina adherons has been purified, and shown to be a heparan sulfate proteoglycan (Schubert, D., and M. LaCorbiere, 1985, J. Cell Biol., 100:56-63). This paper describes the isolation and characterization of a protein in neural retina adherons which interacts specifically with the cell surface receptor. The 20,000-mol-wt protein, called retinal purpurin (RP), stimulates neural retina cell-substratum adhesion and prolongs the survival of neural retina cells in culture. The RP protein interacts with heparin and heparan sulfate, but not with other glycosaminoglycans. Monovalent antibodies against RP inhibit RP-cell adhesion as well as adheron-cell interactions. The RP protein is found in neural retina, but not in other tissues such as brain and muscle. These data suggest that RP plays a role in both the survival and adhesive interactions of neural retina cells.

scholarly journals Phosphatidylserine Is Not the Cell Surface Receptor for Vesicular Stomatitis Virus

2004 ◽  
Vol 78 (20) ◽  
pp. 10920-10926 ◽  
Author(s):  
David A. Coil ◽  
A. Dusty Miller
Keyword(s):  
Cell Surface ◽  
Vesicular Stomatitis Virus ◽  
Virus Entry ◽  
Annexin V ◽  
Cell Types ◽  
Membrane Lipid ◽  
Cell Surface Receptor ◽  
Wide Range ◽  
Surface Receptor ◽  
Vesicular Stomatitis

ABSTRACT The envelope protein from vesicular stomatitis virus (VSV) has become an important tool for gene transfer and gene therapy. It is widely used mainly because of its ability to mediate virus entry into all cell types tested to date. Consistent with the broad tropism of the virus, the receptor for VSV is thought to be a ubiquitous membrane lipid, phosphatidylserine (PS). However, the evidence for this hypothesis is indirect and incomplete. Here, we have examined the potential interaction of VSV and PS at the plasma membrane in more detail. Measurements of cell surface levels of PS show a wide range across cell types from different organisms. We demonstrate that there is no correlation between the cell surface PS levels and VSV infection or binding. We also demonstrate that an excess of annexin V, which binds specifically and tightly to PS, does not inhibit infection or binding by VSV. While the addition of PS to cells does allow increased virus entry, we show that this effect is not specific to the VSV envelope. We conclude that PS is not the cell surface receptor for VSV, although it may be involved in a postbinding step of virus entry.

Role of the Urokinase Receptor (uPAR) in the Cross-Talk of Hematopoietic Stem Cells with the Bone Marrow Microenvironment

Blood ◽  
2008 ◽  
Vol 112 (11) ◽  
pp. 324-324 ◽  
Author(s):  
Nunzia Montuori ◽  
Patrizia Ricci ◽  
Bianca Serio ◽  
Valeria Visconte ◽  
Claudio La Penna ◽  
...  
Keyword(s):  
Bone Marrow ◽  
Cell Adhesion ◽  
Mirror Image ◽  
Cell Surface Receptor ◽  
Hematopoietic Stem ◽  
Stromal Microenvironment ◽  
Surface Receptor ◽  
Cell Adhesion And Migration

Abstract The urokinase-type plasminogen activator receptor (uPAR) is a cell-surface receptor involved in cell adhesion and migration. uPAR binds urokinase (uPA) and vitronectin (VN) and interacts with integrins and chemotaxis receptors. Soluble forms of uPAR (suPAR) have been detected in human plasma and urine. A cleaved form of suPAR (c-suPAR), lacking the N-terminal domain and exposing the sequence SRSRY (aa 88–92), stimulates cell migration by activating fMLP receptors. We recently demonstrated uPAR involvement in G-CSF-induced CD34+ hematopoietic stem cell (HSC) mobilization. We also demonstrated that c-suPAR could induce mobilization of hematopoietic stem/progenitor cells in mice. Since HSC mobilization and homing to bone marrow (BM) are mirror image processes which utilize the same mediators and similar signaling pathways, we investigated whether uPAR and its ligands could play a role in regulating CD34+ HSC interactions with the BM stroma, thus also contributing to HSC homing and engraftment to the BM. We found expression of uPA and VN in cultures of human BM stroma cells. Interestingly, stroma cells also produced suPAR and high amounts of c-suPAR, exposing the chemotactic SRSRY sequence. The role of the different soluble forms of uPAR produced by stroma cells in regulating HSC interactions with the BM microenvironment was analyzed by long term cultures (LTC) of BM and G-CSF mobilized CD34+ HSCs, in the presence of suPAR or the uPAR-derived uPAR84–95 peptide, corresponding to the active site of c-suPAR. Both suPAR and the uPAR84–95 peptide increased the number of adherent and released clonogenic progenitors from LTC of BM and G-CSF mobilized HSCs. To elucidate the mechanism of suPAR and c-suPAR effects on CD34+ HSC interactions with the stromal microenvironment, in vitro adhesion and proliferation assays were performed on CD34+ KG1 cells. suPAR treatment determined a significant increase in CD34+ KG1 cell adhesion whereas c-suPAR increased cell proliferation. Taken together, our results indicate that BM stroma produces soluble forms of uPAR that regulate CD34+ HSC interactions with BM microenvironment, their local proliferation and trafficking from and to BM.

scholarly journals In vivo paracrine interaction between urokinase and its receptor: effect on tumor cell invasion.

1991 ◽  
Vol 115 (4) ◽  
pp. 1107-1112 ◽  
Author(s):  
L Ossowski ◽  
G Clunie ◽  
M T Masucci ◽  
F Blasi
Keyword(s):  
Chorioallantoic Membrane ◽  
Fold Increase ◽  
Cell Types ◽  
Cell Surface Receptor ◽  
In Vivo Model ◽  
Specific Cell ◽  
Upa Receptor ◽  
Surface Receptor

Numerous studies have linked the production of increased levels of urokinase type plasminogen activator (uPA) with the malignant phenotype. It has also been shown that a specific cell surface receptor can bind uPA through a domain distinct and distant from the proteolytic domain. In an in vivo model of invasion, consisting of experimentally modified chorioallantoic membrane (CAM) of a chick embryo, only cells that concurrently expressed both uPA and a receptor for uPA, and in which the receptor was saturated with uPA, were efficient in invasion. To test whether uPA produced by one cell can, in a paracrine fashion, affect the invasive capacity of a receptor-expressing cell, we transfected LB6 mouse cells with human uPA (LB6[uPA]), or human uPA-receptor cDNA (LB6[uPAR]). LB6(uPA) cells released into the medium 1-2 Ploug units of human uPA per 10(6) cells in 24 h. The LB6(uPAR) cells expressed on their surface approximately 12,000 high affinity (Kd 1.7 x 10(-10) M uPA binding sites per cell. Unlabeled LB6(uPA) and 125-IUdR-labeled LB6(uPAR) cells were coinoculated onto experimentally wounded and resealed CAMs and their invasion was compared to that of homologous mixtures of labeled and unlabeled LB6(uPAR) or LB6(uPA) cells. Concurrent presence of both cell types in the CAMs resulted in a 1.8-fold increase of invasion of the uPA-receptor expressing cells. A four-fold stimulation of invasion was observed when cells were cocultured in vitro, prior to in vivo inoculation. Enhancement of invasion was prevented in both sets of experiments by treatment with specific antihuman uPA antibodies, indicating that uPA was the main mediator of the invasion-enhancing, paracrine effect on the receptor-expressing cells.

In vitro biosynthesis of the human cell surface receptor for transferrin

FEBS Letters ◽  
1983 ◽  
Vol 158 (2) ◽  
pp. 259-264 ◽  
Author(s):  
C. Schneider ◽  
U. Asser ◽  
D.R. Sutherland ◽  
M.F. Greaves
Keyword(s):  
Cell Surface ◽  
Human Cell ◽  
Cell Surface Receptor ◽  
Surface Receptor ◽  
In Vitro Biosynthesis

Inhibition of bovine retinal microvascular pericyte proliferation in vitro by adenosine

1992 ◽  
Vol 263 (2) ◽  
pp. H634-H640 ◽  
Author(s):  
J. A. Jackson ◽  
E. C. Carlson
Keyword(s):  
Endothelial Cells ◽  
Cell Surface ◽  
Adenosine Receptor ◽  
Inhibitory Effect ◽  
Cell Surface Receptor ◽  
Dual Function ◽  
Receptor Subtypes ◽  
Retinal Pericytes ◽  
Surface Receptor

Adenosine acts on bovine retinal microvascular pericytes through one or more adenosine receptor subtypes present on the cell surface. Retinal pericytes cultured in medium containing adenosine at concentrations from 10(-6) to 10(-4) M showed significant reduction in proliferation following several days in vitro compared with control cultures. The effects of adenosine were mimicked by polyadenylic acid and inhibited by 8-phenyltheophylline, indicating involvement of a cell surface receptor. Metabolites of adenosine had no effect on pericyte proliferation. An A2 adenosine receptor-specific analogue also inhibited pericyte growth, suggesting that inhibition by adenosine is mediated by A2-receptors and might involve a transient increase in adenosine 3',5'-cyclic monophosphate levels. The results of the present study demonstrate that in addition to demonstrated stimulatory effects on capillary endothelial cells, adenosine also has a direct inhibitory effect on retinal pericytes. We hypothesize a dual function of adenosine within the capillary wall resulting in loss of inhibition of endothelial cells and suggest a role for this nucleoside in pathological neovascularization processes such as proliferative diabetic retinopathy.

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