scholarly journals Apolipoprotein(a) Inhibits In Vitro Tube Formation in Endothelial Cells: Identification of Roles for Kringle V and the Plasminogen Activation System

PLoS ONE ◽  
2013 ◽  
Vol 8 (1) ◽  
pp. e52287 ◽  
Author(s):  
Lei Liu ◽  
Michael B. Boffa ◽  
Marlys L. Koschinsky
2019 ◽  
Vol 235 (5) ◽  
pp. 4545-4558 ◽  
Author(s):  
Luciane Martins ◽  
Bruna Rabelo Amorim ◽  
Cristiane Ribeiro Salmon ◽  
Adriana Franco Paes Leme ◽  
Kamila Rosamilia Kantovitz ◽  
...  

1994 ◽  
Vol 71 (05) ◽  
pp. 684-691 ◽  
Author(s):  
László Damjanovich ◽  
Csaba Turzó ◽  
Róza Ádány

SummaryThe plasminogen activation system is a delicately balanced assembly of enzymes which seems to have primary influence on tumour progression. The conversion of plasminogen into serine protease plasmin with fibrinolytic activity depends on the actual balance between plasminogen activators (urokinase type; u-PA and tissue type; t-PA) and their inhibitors (type 1 and 2 plasminogen activator inhibitors; PAI-1 and PAI-2). The purpose of this study was to determine the exact histological localization of all the major factors involved in plasminogen activation, and activation inhibition (plasmin system) in benign and malignant breast tumour samples. Our results show that factors of the plasmin system are present both in benign and malignant tumours. Cancer cells strongly labelled for both u-PA and t-PA, but epithelial cells of fibroadenoma samples were also stained for plasminogen activators at least as intensively as tumour cells in cancerous tissues. In fibroadenomas, all the epithelial cells were labelled for PAM. Staining became sporadic in malignant tumours, cells located at the periphery of tumour cell clusters regularly did not show reaction for PAI-1. In the benign tumour samples the perialveolar connective tissue stroma contained a lot of PAI-1 positive cells, showing characteristics of fibroblasts; but their number was strongly decreased in the stroma of malignant tumours. These findings indicate that the higher level of u-PA antigen, detected in malignant breast tumour samples by biochemical techniques, does not necessarily indicate increased u-PA production by tumour cells but it might be owing to the increased number of cells producing u-PA as well. In malignant tumours PAI-1 seems to be decreased in the frontage of malignant cell invasion; i.e. malignant cells at the host/tumour interface do not express PAI-1 in morphologically detectable quantity and in the peritumoural connective tissue the number of fibroblasts containing PAI-1 is also decreased.


1997 ◽  
Vol 78 (02) ◽  
pp. 934-938 ◽  
Author(s):  
Hsiun-ing Chen ◽  
Yueh-I Wu ◽  
Yu-Lun Hsieh ◽  
Guey-Yueh Shi ◽  
Meei-Jyh Jiang ◽  
...  

SummaryTo investigate whether the endothelium-platelet interactions may be altered by plasminogen activation, cultured human umbilical vein endothelial cells (ECs) were treated with tissue-type plasminogen activator (t-PA) in the presence of plasminogen, and platelet adhesion to ECs was subsequently measured by using a tapered flow chamber. Our results demonstrated that platelets adhered more readily to t-PA treated EC monolayer than to the control monolayer at all shear stress levels tested. This phenomenon was treatment time-dependent and dose-dependent, and it could be blocked by adding plasmin inhibitors, such as e-amino caproic acid and aprotinin. Adherent platelets on t-PA treated EC monolayer underwent more severe shape change than those on the control monolayer. While the extracellular matrix directly treated with t-PA attracted less platelets than the control matrix did, platelet adhesion to the matrix that was produced by t-PA-treated ECs was unaltered. These data suggest that t-PA treatment on ECs compromised antiplatelet-adhesion capability on their apical surface without altering the reactivity of their extracellular matrix towards platelets.


2021 ◽  
Vol 18 ◽  
Author(s):  
Juxuan Ruan ◽  
Lei Wang ◽  
Jiheng Dai ◽  
Jing Li ◽  
Ning Wang ◽  
...  

Objective: Angiogenesis led by brain microvascular endothelial cells (BMECs) contributes to the remission of brain injury after brain ischemia reperfusion. In this study, we investigated the effects of hydroxysafflor yellow A(HSYA) on angiogenesis of BMECs injured by OGD/R via SIRT1-HIF-1α-VEGFA signaling pathway. Methods: The OGD/R model of BMECs was established in vitro by OGD for 2h and reoxygenation for 24h. At first, the concentrations of vascular endothelial growth factor (VEGF), Angiopoietin (ang) and platelet-derived growth factor (PDGF) in supernatant were detected by ELISA, and the proteins expression of VEGFA, Ang-2 and PDGFB in BMECs were tested by western blot; the proliferation, adhesion, migration (scratch healing and transwell) and tube formation experiment of BMECs; the expression of CD31 and CD34 were tested by immunofluorescence staining. The levels of sirtuin1(SIRT1), hypoxia-inducible factor-1α (HIF-1α), VEGFA mRNA and protein were tested. Results: HSYA up-regulated the levels of VEGF, Ang and PDGF in the supernatant of BMECs under OGD/R, and the protein expression of VEGFA, Ang-2 and PDGFB were increased; HSYA could significantly alleviate the decrease of cell proliferation, adhesion, migration and tube formation ability of BMECs during OGD/R; HSYA enhanced the fluorescence intensity of CD31 and CD34 of BMECs during OGD/R; HSYA remarkably up-regulated the expression of SIRT1, HIF-1α, VEGFA mRNA and protein after OGD/R, and these increase decreased after SIRT1 was inhibited. Conclusion: SIRT1-HIF-1α-VEGFA signaling pathway is involved in HSYA improves angiogenesis of BMECs injured by OGD/R.


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