Relation of Urokinase-Type Plasminogen Activator Expression to Presence and Severity of Atherosclerotic Lesions in Human Coronary Arteries

1998 ◽  
Vol 79 (03) ◽  
pp. 579-586 ◽  
Author(s):  
Teresa Padró ◽  
Martin Steins ◽  
Chang-Xun Li ◽  
Kurt Schmid ◽  
Dieter Hammel ◽  
...  
Keyword(s):  
Plasminogen Activator ◽  
Coronary Arteries ◽  
Plasminogen Activator Inhibitor ◽  
Matrix Remodeling ◽  
Plasminogen Activator Inhibitor 1 ◽  
Atherosclerotic Lesions ◽  
Plaque Disruption ◽  
Type Plasminogen Activator ◽  
Urokinase Type Plasminogen Activator ◽  
Tissue Specimens

SummaryUrokinase-type plasminogen activator (UPA) has been implicated in a broad spectrum of pathological processes – e.g. cell adhesion, migration and proliferation and matrix remodeling – that are considered important features of atherogenesis and plaque disruption. In this study, we have analyzed the content and expression of UPA in human coronary arteries and its relation to the presence and severity of atherosclerotic lesions. Segments of coronary arteries obtained from human heart explants (n = 15) were classified by the presence and types of atherosclerotic lesions. UPA was quantitatively determined in protein extracts of the intimal and medial layers. In situ hybridization and immunohistochemical analyses were performed on serial sections of representative tissue specimens. UPA was detected in the extracts as pro-UPA, UPA complexed to plasminogen activator inhibitor-1, or as otherwise inactive UPA antigen, but not in the active two-chain form. Both functional and total UPA were increased several-fold in extracts of advanced lesions, while the ratios of functional over total UPA showed the opposite trend suggesting enhanced UPA inactivation and turnover. UPA expression in early atherosclerotic lesions was particularly prominent in areas of proliferating SMCs in the abluminal part of the neointima, whereas in advanced lesions UPA was widely expressed in macrophage-rich areas adjacent to the rims and shoulder regions of the necrotic cores. The results strongly suggest a causal involvement of UPA in coronary atherogenesis and its clinical outcome.

Increased secretion of urokinase-type plasminogen activator by human lung microvascular endothelial cells

1998 ◽  
Vol 275 (1) ◽  
pp. L47-L54 ◽  
Author(s):  
Kimiko Takahashi ◽  
Yasuhide Uwabe ◽  
Yoshio Sawasaki ◽  
Toshio Kiguchi ◽  
Hiroyuki Nakamura ◽  
...  
Keyword(s):  
Endothelial Cells ◽  
Plasminogen Activator ◽  
Plasminogen Activator Inhibitor ◽  
Lung Fibroblasts ◽  
Microvascular Endothelial Cells ◽  
Plasminogen Activator Inhibitor 1 ◽  
Type Plasminogen Activator ◽  
Urokinase Type Plasminogen Activator ◽  
Microvascular Endothelial ◽  
Activator Inhibitor

Human lung microvascular endothelial cells (HLMECs) secreted 1.5–15 times more urokinase-type plasminogen activator (uPA) antigen than human hepatic microvascular endothelial cells, human umbilical vein endothelial cells (HUVECs), angioma endothelial cells, and lung fibroblasts. All of these cells also secreted a 100-fold greater amount of plasminogen activator inhibitor-1 than of uPA antigen, and uPA activities were not detected in the culture medium. The expression of uPA mRNA in HLMECs was higher (100-fold) compared with HUVECs, angioma endothelial cells, and lung fibroblasts. HLMECs secreted uPA antigen on both the luminal and basal sides of the cells. On the other hand, HLMECs secreted a 10- to 15-fold lower amount of tissue-type plasminogen activator than HUVECs, mostly on the luminal side. After stimulation with interleukin (IL)-1β, HLMECs secreted a six- to ninefold amount of uPA antigen. In contrast, no stimulatory effect was observed in HUVECs even under high IL-1β concentrations. The secretion of uPA and plasminogen activator inhibitor-1 from HLMECs was also enhanced by tumor necrosis factor-α and IL-2. These results suggest that HLMECs may contribute not only to the patency of lung vessels but also to the maintenance of alveolar functions through the production and secretion of uPA, especially in the presence of inflammatory cytokines.

scholarly journals Deep mutational scanning of the plasminogen activator inhibitor-1 functional landscape

2021 ◽  
Author(s):  
Zachary M Huttinger ◽  
Laura M Haynes ◽  
Andrew Yee ◽  
Colin A Kretz ◽  
David R Siemieniak ◽  
...  
Keyword(s):  
Amino Acid ◽  
Plasminogen Activator ◽  
Plasminogen Activator Inhibitor ◽  
Single Amino Acid ◽  
Plasminogen Activator Inhibitor 1 ◽  
Missense Variants ◽  
Type Plasminogen Activator ◽  
Urokinase Type Plasminogen Activator ◽  
Activator Inhibitor ◽  
Pai 1

The serine protease inhibitor (SERPIN) plasminogen activator inhibitor-1 (PAI-1) is a key regulator of the fibrinolytic system, inhibiting the serine proteases tissue- and urokinase-type plasminogen activator (tPA and uPA, respectively). Missense variants may render PAI-1 non-functional through misfolding, leading to its turnover as a protease substrate, or to a more rapid transition to the latent/inactive state. Deep mutational scanning was performed to evaluate the impact of amino acid sequence variation on PAI-1 inhibition of uPA using an M13 filamentous phage display system. The effects of single amino acid substitutions on PAI-1's functional inhibition of its canonical target proteases, tPA and uPA , have been determined for only a small fraction of potential mutations. To construct a more comprehensive dataset, a mutagenized PAI-1 library, encompassing ~70% of potential single amino acid substitutions, was displayed on M13 filamentous phage. From this library, the relative effects of 27% of all possible missense variants on PAI-1 inhibition of urokinase-type plasminogen activator were determined using high-throughput DNA sequencing with 826 missense variants demonstrating conserved inhibitory activity and 1137 resulting in loss of PAI-1 function. Comparison of these deep mutational scanning results to predictions from PolyPhen-2 and SIFT demonstrate the limitations of these algorithms, consistent with similar reports for other proteins. Comparison to common human PAI-1 gene variants present in the gnomAD database is consistent with evolutionary selection against loss of PAI-1 function. These findings provide insight into structure-function relationships for PAI-1 and other members of the SERPIN superfamily.

scholarly journals Is plasminogen activator inhibitor-1 the molecular switch that governs urokinase receptor-mediated cell adhesion and release?

1996 ◽  
Vol 134 (6) ◽  
pp. 1563-1571 ◽  
Author(s):  
G Deng ◽  
S A Curriden ◽  
S Wang ◽  
S Rosenberg ◽  
D J Loskutoff
Keyword(s):  
Cell Adhesion ◽  
Plasminogen Activator ◽  
Plasminogen Activator Inhibitor ◽  
Migration And Invasion ◽  
Binding Motif ◽  
Plasminogen Activator Inhibitor 1 ◽  
Amino Terminal ◽  
Type Plasminogen Activator ◽  
Urokinase Type Plasminogen Activator ◽  
Pai 1

Induction of the urokinase type plasminogen activator receptor (uPAR) promotes cell adhesion through its interaction with vitronectin (VN) in the extracellular matrix, and facilitates cell migration and invasion by localizing uPA to the cell surface. We provide evidence that this balance between cell adhesion and cell detachment is governed by PA inhibitor-1 (PAI-1). First, we demonstrate that uPAR and PAI-1 bind to the same site in VN (i.e., the amino-terminal somatomedin B domain; SMB), and that PAI-1 competes with uPAR for binding to SMB. Domain swapping and mutagenesis studies indicate that the uPAR-binding sequence is located within the central region of the SMB domain, a region previously shown to contain the PAI-1-binding motif. Second, we show that PAI-1 dissociates bound VN from uPAR and detaches U937 cells from their VN substratum. This PAI-1 mediated release of cells from VN appears to occur independently of its ability to function as a protease inhibitor, and may help to explain why high PAI-1 levels indicate a poor prognosis for many cancers. Finally, we show that uPA can rapidly reverse this effect of PAI-1. Taken together, these results suggest a dynamic regulatory role for PAI-1 and uPA in uPAR-mediated cell adhesion and release.

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