scholarly journals TLR4 Response to LPS Is Reinforced by Urokinase Receptor

2020 ◽  
Vol 11 ◽  
Author(s):  
Yulia Kiyan ◽  
Sergey Tkachuk ◽  
Song Rong ◽  
Anna Gorrasi ◽  
Pia Ragno ◽  
...  
Keyword(s):  
Scavenger Receptor ◽  
Cecal Ligation ◽  
Type Plasminogen Activator ◽  
Upar Expression ◽  
Urokinase Type Plasminogen Activator ◽  
Sepsis Therapy ◽  
Inflammatory Processes ◽  
Underlying Mechanisms

GPI-anchored uPAR is the receptor for the extracellular serine protease urokinase-type plasminogen activator (uPA). Though uPAR role in inflammatory processes is documented, underlying mechanisms are not fully understood. In this study we demonstrate that uPAR is a part of Toll-like receptor 4 (TLR4) interactome. Downregulation of uPAR expression resulted in diminished LPS-induced TLR4 signaling, less activation of NFκB, and decreased secretion of inflammatory mediators in myeloid and non-myeloid cells in vitro. In vivo uPAR−/− mice demonstrated better survival, strongly diminished inflammatory response and better organ functions in cecal ligation and puncture mouse polymicrobial sepsis model. Mechanistically, GPI-uPAR and soluble uPAR colocalized with TLR4 on the cell membrane and interacted with scavenger receptor CD36. Our data show that uPAR can interfere with innate immunity response via TLR4 and this mechanism represents a potentially important target in inflammation and sepsis therapy.

scholarly journals Urokinase receptor associates with TLR4 interactome to promote LPS response

2020 ◽  
Author(s):  
Yulia Kiyan ◽  
Sergei Tkachuk ◽  
Anna Gorrasi ◽  
Pia Ragno ◽  
Inna Dumler ◽  
...  
Keyword(s):  
Intracellular Signaling ◽  
Transmembrane Domain ◽  
Scavenger Receptor ◽  
Cecal Ligation ◽  
Membrane Receptors ◽  
Proteolytic Cascade ◽  
Sepsis Therapy ◽  
Underlying Mechanisms

AbstractGPI-anchored uPAR is the receptor for the extracellular serine protease urokinase-type plasminogen activator (uPA). Binding of uPA to uPAR localizes proteolytic cascade activation at the cell surface and can induce intracellular signaling. As uPAR possesses no transmembrane domain, it relies on uPAR cross-talk with various membrane receptors. Though uPAR role in inflammatory processes is well documented, underlying mechanisms are not fully understood. In this study we demonstrate that uPAR is a part of Toll-like receptor 4 (TLR4) interactome. GPI-uPAR and soluble uPAR colocalized with TLR4 on the cell membrane and interacted with scavenger receptor CD36. We show that downregulation of uPAR expression resulted in diminished LPS-induced TLR4 signaling, less activation of NFκB, and decreased secretion of inflammatory mediators in myeloid and non-myeloid cells in vitro. In vivo uPAR−/− mice demonstrated strongly diminished inflammatory response and better organ functions in cecal ligation and puncture mouse polymicrobial sepsis model. Our data show that uPAR can interfere with innate immunity response via TLR4 and this mechanism represents a potentially important target in inflammation and sepsis therapy.

ON THE MECHANISM OF THE IN VIVO SYNERGISM BETWEEN TISSUE-TYPE PLASMINOGEN ACTIVATOR (t-PA) AND SINGLE CHAIN UROKINASE-TYPE PLASMINOGEN ACTIVATOR (scu-PA)

1987 ◽  
Author(s):  
J M Stassen ◽  
D Collen
Keyword(s):  
Plasminogen Activator ◽  
Rabbit Model ◽  
Sequential Therapy ◽  
Tissue Type ◽  
Single Chain ◽  
Molar Ratios ◽  
Type Plasminogen Activator ◽  
Urokinase Type Plasminogen Activator

t-PA and scu-PA, in molar ratios between 1:4 and 4:1 do not act synergically in vitro (Thromb. Haemost. 56,35,1986) but display marked synergism in a rabbit model (Circulation 74, 838, 1986) and in man (Am. Heart J. 112, 1083, 1986). To investigate the mechanism of in vivo synergism in the rabbit model (J. Clin. Invest. 71, 368, 1983), t-PA and scu-PA were infused 1) simultaneously over 4 hrs, 2) t-PA over 1 hr, then 15 min later scu-PA over 2 hrs and 3) scu-PA over 1 hr, then 15 min later t-PA over 2 hrs.Significant synergism on thrombolysis is observed when t-PA and scu-PA are infused simultaneously or when t-PA is followed by scu-PA but not when scu-PA is followed by t-PA. These results suggest that low dose t-PA induces some plasminogen activation, sufficient to partially degrade fibrin, exposing COOH-terminal lysines with high affinity for plasminogen (Eur. J. Biochem. 140, 513, 1984). scu-PA might then activate surface-bound Glu-pla-minogen more efficiently.Sequential therapy with t-PA (or any other agent which "predigests" the thrombus), followed by scu-PA might constitute an alternative to simultaneous infusion of synergistic thrombolytic agents.

scholarly journals Soluble Urokinase Receptors in Focal Segmental Glomerulosclerosis: A Review on the Scientific Point of View

2016 ◽  
Vol 2016 ◽  
pp. 1-14 ◽  
Author(s):  
Andreas Kronbichler ◽  
Moin A. Saleem ◽  
Björn Meijers ◽  
Jae Il Shin
Keyword(s):  
Focal Segmental Glomerulosclerosis ◽  
Point Of View ◽  
Soluble Form ◽  
Glomerular Diseases ◽  
Segmental Glomerulosclerosis ◽  
Type Plasminogen Activator ◽  
Urokinase Type Plasminogen Activator ◽  
End Stage

Focal segmental glomerulosclerosis (FSGS) is one of the primary glomerular disorders in both children and adults which can progress to end-stage renal failure. Although there are genetic and secondary causes, circulating factors have also been regarded as an important factor in the pathogenesis of FSGS, because about 40% of the patients with FSGS have recurrence after renal transplantation. Soluble urokinase-type plasminogen activator receptor (suPAR) is a soluble form of uPAR, which is a membrane-bound protein linked to GPI in various immunologically active cells, including podocytes. It has recently been suggested as a potential circulating factor in FSGS by in vitro podocyte experiments, in vivo mice models, and human studies. However, there have also been controversies on this issue, because subsequent studies showed conflicting results. suPAR levels were also increased in patients with other glomerular diseases and were inversely correlated with estimated glomerular filtration rate. Nevertheless, there has been no balanced review on this issue. In this review, we compare the conflicting data on the involvement of suPAR in the pathogenesis of FSGS and shed light on interpretation by taking into account many points and the potential variables and confounders influencing serum suPAR levels.

Participation of urokinase-type plasminogen activator receptor in the clearance of fibrin from the lung

1999 ◽  
Vol 277 (3) ◽  
pp. L573-L579 ◽  
Author(s):  
Noboru Hattori ◽  
Thomas H. Sisson ◽  
Yin Xu ◽  
Tushar J. Desai ◽  
Richard H. Simon
Keyword(s):  
Plasminogen Activator ◽  
Cell Surface Receptor ◽  
Biologically Relevant ◽  
Knowing That ◽  
Type Plasminogen Activator ◽  
Urokinase Type Plasminogen Activator ◽  
Surface Receptor ◽  
Species Specific

In vitro studies have demonstrated that the binding of urokinase-type plasminogen activator (uPA) to its cell surface receptor (uPAR) greatly accelerates plasminogen activation. However, the role of uPAR in clearing abnormal fibrin deposits from the lung is uncertain. Knowing that uPA binding to uPAR is species specific, we used adenoviral vectors to transfer human or murine uPA genes into human or mouse epithelial cells in vitro and to mouse lungs in vivo. By measuring degradation of fluorescein-labeled fibrin, we found that uPA lysed fibrin matrices more efficiently when expressed in cells of the same species. A monoclonal antibody that blocks the binding of human uPA to human uPAR suppressed fibrin degradation by human cells expressing human uPA but not murine uPA. Importantly, 3 days after intratracheal delivery of the vectors, mice receiving murine uPA transgenes degraded fibrin matrices formed within their air spaces more efficiently than animals transduced with human uPA genes. These results show that uPA bound to uPAR increases the efficiency of fibrinolysis on epithelial cell surfaces in a biologically relevant fashion.

scholarly journals In Vitro Study of the Fibrinolytic Activity via Single Chain Urokinase-Type Plasminogen Activator and Molecular Docking of FGFC1

Molecules ◽  
2021 ◽  
Vol 26 (7) ◽  
pp. 1816
Author(s):  
Chunli Gao ◽  
Quan Shen ◽  
Pengjie Tang ◽  
Yuling Cao ◽  
Houwen Lin ◽  
...  
Keyword(s):  
Molecular Docking ◽  
Plasminogen Activator ◽  
Binding Sites ◽  
Fibrinolytic Activity ◽  
Hydrophobic Interactions ◽  
Single Chain ◽  
Type Plasminogen Activator ◽  
Urokinase Type Plasminogen Activator

Fungi fibrinolytic compound 1 (FGFC1) is a rare marine-derived compound that can enhance fibrinolysis both in vitro and in vivo. The fibrinolytic activity characterization of FGFC1 mediated by plasminogen (Glu-/Lys-) and a single-chain urokinase-type plasminogen activator (pro-uPA) was further evaluated. The binding sites and mode of binding between FGFC1 and plasminogen were investigated by means of a combination of in vitro experiments and molecular docking. A 2.2-fold enhancement of fibrinolytic activity was achieved at 0.096 mM FGFC1, whereas the inhibition of fibrinolytic activity occurred when the FGFC1 concentration was above 0.24 mM. The inhibition of fibrinolytic activity of FGFC1 by 6-aminohexanoic acid (EACA) and tranexamic acid (TXA) together with the docking results revealed that the lysine-binding sites (LBSs) play a crucial role in the process of FGFC1 binding to plasminogen. The action mechanism of FGFC1 binding to plasminogen was inferred, and FGFC1 was able to induce plasminogen to exhibit an open conformation by binding through the LBSs. The molecular docking results showed that docking of ligands (EACA, FGFC1) with receptors (KR1–KR5) mainly occurred through hydrophilic and hydrophobic interactions. In addition, the binding affinity values of EACA to KR1–KR5 were −5.2, −4.3, −3.7, −4.5, and −4.3 kcal/moL, respectively, and those of FGFC1 to KR1–KR5 were −7.4, −9.0, −6.3, −8.3, and −6.7 kcal/moL, respectively. The findings demonstrate that both EACA and FGFC1 bound to KR1–KR5 with moderately high affinity. This study could provide a theoretical basis for the clinical pharmacology of FGFC1 and establish a foundation for practical applications of FGFC1.

scholarly journals uPAR Directly Interacts with LDLR-like Proteins to Induce Angiogenic Endothelial Cell Behavior

Blood ◽  
2014 ◽  
Vol 124 (21) ◽  
pp. 4172-4172
Author(s):  
Clemens Pausz ◽  
Rula Mawas ◽  
Matthias Unseld ◽  
Anastasia Chilla ◽  
René Novotny ◽  
...  
Keyword(s):  
Endothelial Cell ◽  
Endothelial Cell Migration ◽  
Migration And Invasion ◽  
Binding Motif ◽  
Wild Type ◽  
Type Plasminogen Activator ◽  
Urokinase Type Plasminogen Activator ◽  
Domain 3

Abstract In this study we characterized a conserved motif of domain 3 of the urokinase-type plasminogen activator receptor (uPAR) to directly interact with low-density lipoprotein receptor (LDLR)-related protein (LRP) family proteins, thereby affecting endothelial cell motility and angiogenesis in vitro and in vivo. There is increasing evidence that uPAR plays a central role in growth factor induced endothelial cell activation. Beside its proteolytic role, urokinase-type plasminogen activator (uPA) / uPAR-complex formation induces intracellular signal transduction, which leads to endothelial cell migration and invasion. Since uPAR is a GPI-anchored protein, an interaction with transmembrane proteins - such as members of the LDL-receptor family - is required, inducing signal transduction but also regulating distribution of uPAR via its internalization and recycling to the leading edge. Recently, a direct interaction between uPAR and LRP-family members has been suggested to be sufficient to mediate internalization of uPAR-complex. A crystal structure analysis revealed a small sequence of domain 3 (D3) of uPAR, to be highly exposed upon uPA binding to its receptor. Applying affinity chromatography analysis as well as mutation expression studies, we identified the sequence as an LRP-binding motif, which affects endothelial cell spreading, migration and invasion upon VEGF in vivo as well as in vitro. In detail, matrigel-filled angioreactors with embedded retroviral constructs, carrying wild-type or modified uPAR genes, were implanted subcutaneously into uPAR deficient C57BL/6 mice. After explantation, blood vessel in-growth analysis revealed that only angioreactors with reconstituted wild-type uPAR but not reactors with modified uPAR, being deficient in LDLR interaction, showed angiogenesis. To test a therapeutic impact, peptides mimicking the binding motif and competitive for LDLR binding were used. We found that in a dose dependent manner the peptides did not only block uPAR/LDLR-like protein interaction, but were also capable of blocking VEGF-induced endothelial cell migration in vitro. In summary, our data show that a conserved motif of uPAR domain 3 is capable to interact with LDLR-like proteins, which is required for efficient growth-factor induced endothelial cell behavior. Preliminary functional data suggest that this extracellular motif might be a potential therapeutic target in angiogenesis dependent diseases such as cancer. Disclosures No relevant conflicts of interest to declare.

scholarly journals Upregulation of Monocyte Urokinase Plasminogen Activator Receptor during Human Endotoxemia

2000 ◽  
Vol 68 (4) ◽  
pp. 2156-2160 ◽  
Author(s):  
Pascale E. P. Dekkers ◽  
Tessa ten Hove ◽  
Anje A. te Velde ◽  
Sander J. H. van Deventer ◽  
Tom van der Poll
Keyword(s):  
Plasminogen Activator ◽  
Leukocyte Adhesion ◽  
Urokinase Plasminogen Activator Receptor ◽  
Necrosis Factor Alpha ◽  
Human Endotoxemia ◽  
Type Plasminogen Activator ◽  
Upar Expression ◽  
And Migration

ABSTRACT The receptor for urokinase-type plasminogen activator (uPAR) (CD87) plays an important role in leukocyte adhesion and migration. To assess the effect of endotoxin on cellular uPAR, uPAR expression was determined on leukocytes by fluorescence-activated cell sorter analysis in seven healthy subjects following intravenous injection of endotoxin (lot G; 4 ng/kg). Endotoxin induced a transient increase in uPAR expression on monocytes, reaching a 92% ± 46% increase over baseline expression after 6 h (P < 0.05). Endotoxin did not influence uPAR expression on granulocytes, while uPAR remained undetectable on lymphocytes. Endotoxin also increased soluble uPAR levels in plasma (P < 0.05). Stimulation of human whole blood with endotoxin or gram-positive stimuli in vitro also resulted in an upregulation of monocyte uPAR expression. Although tumor necrosis factor alpha (TNF) upregulated monocyte uPAR expression, anti-TNF did not influence the endotoxin-induced increase in monocyte uPAR expression. These data suggest that infectious stimuli may influence monocyte function in vivo by enhancing the expression of uPAR.

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