scholarly journals In vitro analysis of the tissue plasminogen activator promoter reveals a GC box-binding activity present in murine brain but undetectable in kidney and liver.

1991 ◽  
Vol 11 (6) ◽  
pp. 3139-3147 ◽  
Author(s):  
L T Pecorino ◽  
A L Darrow ◽  
S Strickland
Keyword(s):  
Dna Binding ◽  
Plasminogen Activator ◽  
Tissue Plasminogen Activator ◽  
Binding Activity ◽  
Transcriptional Level ◽  
Mrna Levels ◽  
Tissue Plasminogen ◽  
Murine Brain ◽  
Gc Box

Tissue plasminogen activator (t-PA) mRNA levels are high in murine brain, lower in kidney, and undetectable in liver. Differences in t-PA mRNA levels are regulated in part at the transcriptional level. Brain, kidney, and liver nuclear extracts direct regulated transcription from the murine t-PA promoter in a manner that reflects the relative levels of t-PA gene expression in these tissues in vivo. Analysis of mutants has defined two GC box motifs as important elements for regulated transcription in vitro. Upon investigation of protein-DNA binding, we detected an activity in brain extracts which was not detected in kidney or liver extracts. An Sp1-like factor also binds to this region in all three tissue types. DNA interference experiments show that the brain-enriched binding activity and the Sp1-like factor contact the same GC-rich sequences. These studies provide additional evidence that brain-enriched DNA-binding activities can interact with sequences also recognized by ubiquitous transcription factors.

In vitro analysis of the tissue plasminogen activator promoter reveals a GC box-binding activity present in murine brain but undetectable in kidney and liver

1991 ◽  
Vol 11 (6) ◽  
pp. 3139-3147
Author(s):  
L T Pecorino ◽  
A L Darrow ◽  
S Strickland
Keyword(s):  
Dna Binding ◽  
Plasminogen Activator ◽  
Tissue Plasminogen Activator ◽  
Binding Activity ◽  
Transcriptional Level ◽  
Mrna Levels ◽  
Tissue Plasminogen ◽  
Murine Brain ◽  
Gc Box

Tissue plasminogen activator (t-PA) mRNA levels are high in murine brain, lower in kidney, and undetectable in liver. Differences in t-PA mRNA levels are regulated in part at the transcriptional level. Brain, kidney, and liver nuclear extracts direct regulated transcription from the murine t-PA promoter in a manner that reflects the relative levels of t-PA gene expression in these tissues in vivo. Analysis of mutants has defined two GC box motifs as important elements for regulated transcription in vitro. Upon investigation of protein-DNA binding, we detected an activity in brain extracts which was not detected in kidney or liver extracts. An Sp1-like factor also binds to this region in all three tissue types. DNA interference experiments show that the brain-enriched binding activity and the Sp1-like factor contact the same GC-rich sequences. These studies provide additional evidence that brain-enriched DNA-binding activities can interact with sequences also recognized by ubiquitous transcription factors.

Binding of Tissue Plasminogen Activator to Vascular Grafts

1989 ◽  
Vol 61 (01) ◽  
pp. 131-136 ◽  
Author(s):  
Richard A Harvey ◽  
Hugh C Kim ◽  
Jonathan Pincus ◽  
Stanley Z Trooskin ◽  
Josiah N Wilcox ◽  
...  
Keyword(s):  
Plasminogen Activator ◽  
Tissue Plasminogen Activator ◽  
Fibrinolytic Activity ◽  
Polymer Surface ◽  
Enzymic Activity ◽  
Vascular Prostheses ◽  
Chemically Modified ◽  
Insoluble Surfactant ◽  
Tissue Plasminogen

SummaryTissue plasminogen activator labeled with radioactive iodine (125I-tPA) was immobilized on vascular prostheses chemically modified with a thin coating of water-insoluble surfactant, tridodecylmethylammonium chloride (TDM AC). Surfactant- treated Dacron, polytetrafluoroethylene (PTFE), silastic, polyethylene and polyurethane bound appreciable amounts of 125I- tPA (5-30 μg 125I-tPA/cm2). Upon exposure to human plasma, the amount of 125I-tPA bound to the surface shows an initial drop during the first hour of incubation, followed by a slower, roughly exponential release with a t½ of appoximately 75 hours. Prostheses containing bound tPA show fibrinolytic activity as measured both by lysis of clots formed in vitro, and by hydrolysis of a synthetic polypeptide substrate. Prior to incubation in plasma, tPA bound to a polymer surface has an enzymic activity similar, if not identical to that of the native enzyme in buffered solution. However, exposure to plasma causes a decrease in the fibrinolytic activity of both bound tPA and enzyme released from the surface of the polymer. These data demonstrate that surfactant-treated prostheses can bind tPA, and that these chemically modified devices can act as a slow-release drug delivery system with the potential for reducing prosthesis-induced thromboembolism.

Uptake and Degradation of Tissue Plasminogen Activator in Rat Liver

1988 ◽  
Vol 59 (03) ◽  
pp. 474-479 ◽  
Author(s):  
Monica Einarsson ◽  
Bård Smedsrød ◽  
Håkan Pertoft
Keyword(s):  
Endothelial Cells ◽  
Plasminogen Activator ◽  
Tissue Plasminogen Activator ◽  
Rat Liver ◽  
Liver Cells ◽  
Terminal Phase ◽  
Tissue Plasminogen ◽  
Liver Endothelial Cells ◽  
Parenchymal Cells

SummaryThe mechanism of uptake of tissue plasminogen activator (tPA) in rat liver was studied. Radio-iodinated tPA was removed from the circulation after intravenous administration in a biphasic mode. The initial half life, t1/2(α), and the terminal phase, t1/2(β), were determined to be 0.5 min and 7.5 min, resp. Separation of the liver cells by collagenase perfusion and density centrifugation, revealed that the uptake per cell was two to three times higher in the non-parenchymal cells than in the parenchymal cells.Endocytosis of fluorescein isothiocyanate-labelled or 125I-labelled tPA was studied in pure cultures of liver cells in vitro. Liver endothelial cells and parenchymal cells took up and degraded tPA. Endocytosis was more efficient in liver endothelial cells than in parenchymal cells, and was almost absent in Kupffer cells.Competitivb inhibition experiments showing that excess unlabelled tPA could compete with the uptake and degradation of 125I-tPA, suggested that liver endothelial cells and parenchymal cells interact with the activator in a specific manner. Endocytosis of trace amounts of 125I-tPA in cultures of liver endothelial cells and parenchymal cells was inhibited by 50% in the presence of 19 nM unlabelled tPA. Agents that interfere with one or several steps of the endocytic machinery inhibited uptake and degradation of 125I-tPA in both cell types.These findings suggest that 1) liver endothelial cells and parenchymal cells are responsible for the rapid hepatic clearance of intravenously administered tPA; 2) the activator is taken up in these cells by specific endocytosis, and 3) endocytosed tPA is transported to the lysosomes where it is degraded.

Tissue Plasminogen Activator Expression in Endothelial Cells Exposed to Cyclic Strain in Vitro

1992 ◽  
Vol 1 (1) ◽  
pp. 43-50 ◽  
Author(s):  
Toshiaki Iba ◽  
Bauer E. Sumpio
Keyword(s):  
Endothelial Cells ◽  
Plasminogen Activator ◽  
Tissue Plasminogen Activator ◽  
Cyclic Strain ◽  
Neutral Position ◽  
Messenger Ribonucleic Acid ◽  
Tissue Plasminogen ◽  
Pai 1

The effects of cyclic strain on the production of tissue plasminogen activator (tPA) and type 1 plasminogen activator inhibitor (PAI-1) by cultured endothelial cells (EC) were examined. Human saphenous vein EC were seeded in selective areas of culture plates with flexible membrane bottoms (corresponding to specific strain regions) and grown to confluence. Membranes were deformed by vacuum (-20 kPa) at 60 cycles/min (0.5 s strain alternating with 0.5 s relaxation in the neutral position) for 5 days. EC grown in the periphery were subjected to 7-24% strain, while cells grown in the center experienced less than 7% strain. The results show a significant increase in immunoreactive tPA production on days 1, 3 and 5 compared to day 0 in EC subjected to more than 7% cyclic strain. There was no significant elevation of tPA in the medium of EC subjected to less than 7% strain. tPA activity could only be detected in the medium of EC subjected to more than 7% cyclic strain. PAI-1 levels in the medium were not significantly different in either group. In addition, immunocytochemical detection of intracellular tPA and messenger ribonucleic acid (mRNA) expression of tPA (assessed by the reverse transcriptase polymerase chain reaction utilizing tPA specific sense and antisense primers) was significantly increased in EC subjected to more than 7% cyclic strain. We conclude that a 60 cycles/min regimen of strain that is greater than 7% can selectively stimulate tPA production by EC in vitro and may contribute to the relative nonthrombogenicity of the endothelium in vivo.

scholarly journals Tissue Plasminogen Activator Coating on Implant Surfaces Reduces Staphylococcus aureus Biofilm Formation

2015 ◽  
Vol 82 (1) ◽  
pp. 394-401 ◽  
Author(s):  
Jakub Kwiecinski ◽  
Manli Na ◽  
Anders Jarneborn ◽  
Gunnar Jacobsson ◽  
Marijke Peetermans ◽  
...  
Keyword(s):  
Staphylococcus Aureus ◽  
Plasminogen Activator ◽  
Tissue Plasminogen Activator ◽  
Medical Devices ◽  
Biofilm Formation ◽  
Bacterial Biofilm ◽  
Content Type ◽  
Tissue Plasminogen

ABSTRACTStaphylococcus aureusbiofilm infections of indwelling medical devices are a major medical challenge because of their high prevalence and antibiotic resistance. As fibrin plays an important role inS. aureusbiofilm formation, we hypothesize that coating of the implant surface with fibrinolytic agents can be used as a new method of antibiofilm prophylaxis. The effect of tissue plasminogen activator (tPA) coating onS. aureusbiofilm formation was tested within vitromicroplate biofilm assays and anin vivomouse model of biofilm infection. tPA coating efficiently inhibited biofilm formation by variousS. aureusstrains. The effect was dependent on plasminogen activation by tPA, leading to subsequent local fibrin cleavage. A tPA coating on implant surfaces prevented both early adhesion and later biomass accumulation. Furthermore, tPA coating increased the susceptibility of biofilm infections to antibiotics.In vivo, significantly fewer bacteria were detected on the surfaces of implants coated with tPA than on control implants from mice treated with cloxacillin. Fibrinolytic coatings (e.g., with tPA) reduceS. aureusbiofilm formation bothin vitroandin vivo, suggesting a novel way to prevent bacterial biofilm infections of indwelling medical devices.

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