scholarly journals High-glucose incubation of human umbilical-vein endothelial cells does not alter expression and function either of G-protein α-subunits or of endothelial NO synthase

1996 ◽  
Vol 315 (1) ◽  
pp. 281-287 ◽  
Author(s):  
Gudrun MANCUSI ◽  
Caroline HUTTER ◽  
Sabina BAUMGARTNER-PARZER ◽  
Kurt SCHMIDT ◽  
Wolfgang SCHÜTZ ◽  
...  

Alterations in G-protein-controlled signalling pathways (primarily pathways controlled by Gs and Gi) have been reported to occur in animal models of diabetes mellitus. We have therefore studied the effect of a long-term exposure of human umbilical vein endothelial cells to elevated concentrations of glucose on expression and function of G-protein subunits and endothelial NO synthase. Long-term incubation in high glucose (30 mM for 15 days) did not affect the levels of Giα-2, Gqα, the splice variants (long and short form) of Gsα, and the G-protein β-subunits or adenylate cyclase activity: basal, as well as isoprenaline-, forskolin- and guanosine 5´-[γ-thio]triphosphate-stimulated enzyme activities were comparable in high- and low-glucose-treated cells, thus ruling out any functional changes in the stimulatory pathway. Pretreatment of endothelial cells with pertussis toxin blocked a substantial fraction (50%) of the mitogenic response to serum factor(s) which depend(s) on functional Gi2. The sensitivity of cells cultured in high glucose was comparable with that of the paired controls maintained in normal glucose (EC50 = 3.1±0.5 and 3.3±0.4 ng/ml respectively). Similarly, we failed to detect any differences in endothelial NO synthase expression, or intracellular distribution and basal activity of the enzyme in endothelial cells cultured in high glucose. Stimulation of NO synthase in intact cells revealed a comparable response to the calcium ionophore (A23187). In contrast, stimulation with histamine (which acts via H1-receptors predominantly coupled to Gq) resulted in a significantly increased response in the cells maintained in high glucose. These data are suggestive of an altered H1-histamine receptor–Gq–phospholipase C pathway in endothelial cells cultured in high glucose concentrations, but rule out any glucose-induced functional changes in Gs- and Gi-controlled signalling pathways.

1995 ◽  
Vol 74 (02) ◽  
pp. 698-703 ◽  
Author(s):  
Catherine Lenich ◽  
Ralph Pannell ◽  
Victor Gurewich

SummaryFactor XII has long been implicated in the intrinsic pathway of fibrinolysis, but the mechanism by which it triggers plasminogen activation and targets fibrinolysis has not been established. In the present study, the assembly and function of activated Factor XII (F.XIIa), prourokinase (pro-u-PA), high molecular weight kininogen (H-kininogen), and prekallikrein on human umbilical vein endothelial cells (HUVEC) was investigated. 125I-prekallikrein was shown to bind to HUVEC via receptor-bound H-kininogen in the presence of 50 μM ZnCl2. After the addition of F.XIIa, 78% of the 125I-prekallikrein initially bound to HUVEC was converted to 125I-kallikrein. However, only 6% of the HUVEC-bound 125I-pro-u-PA was thereby activated. This discrepancy was shown to be related to rapid dissociation (>50% within 15 min) of prekallikrein/kallikrein, but not pro-u-PA, from HUVEC. Increasing the level of cell-bound kallikrein increased the portion of cell-bound pro-u-PA activated, indicating that their co-localization was important for this pathway. Finally, F.XIIa was shown to trigger plasminogen activation on HUVEC via this pathway. This assembly of reactants on the endothelium suggests a mechanism whereby local fibrinolysis may be triggered by blood coagulation.


2015 ◽  
Vol 3 (44) ◽  
pp. 8717-8728 ◽  
Author(s):  
Xin Li ◽  
Shuheng Yuan ◽  
Si Chen ◽  
Rifang Luo ◽  
Kaiqin Xiong ◽  
...  

An angiopoietin-1 functionalized surface was establishedviapolydopamine coating and regulated HUVECs survival, proliferation and function.


2021 ◽  
Vol 12 ◽  
Author(s):  
Qin Zhang ◽  
Jing Long ◽  
Nannan Li ◽  
Xuelian Ma ◽  
Lisheng Zheng

Hyperglycemia exposure results in the dysfunction of endothelial cells (ECs) and the development of diabetic complications. Circular RNAs (circRNAs) have been demonstrated to play critical roles in EC dysfunction. The current study aimed to explore the role and mechanism of circRNA CLIP–associating protein 2 (circ_CLASP2, hsa_circ_0064772) on HG-induced dysfunction in human umbilical vein endothelial cells (HUVECs). Quantitative real-time polymerase chain reaction (qRT-PCR) was used to assess the levels of circ_CLASP2, miR-140-5p and F-box, and WD repeat domain-containing 7 (FBXW7). The stability of circ_CLASP2 was identified by the actinomycin D and ribonuclease (RNase) R assays. Cell colony formation, proliferation, and apoptosis were measured by a standard colony formation assay, colorimetric 3-(4, 5-dimethylthiazol-2-yl)-2, 5-diphenyl-2H-tetrazolium bromide (MTT) assay, and flow cytometry, respectively. Western blot analysis was performed to determine the expression of related proteins. Targeted correlations among circ_CLASP2, miR-140-5p, and FBXW7 were confirmed by dual-luciferase reporter assay. High glucose (HG) exposure downregulated the expression of circ_CLASP2 in HUVECs. Circ_CLASP2 overexpression or miR-140-5p knockdown promoted proliferation and inhibited apoptosis of HUVECs under HG conditions. Circ_CLASP2 directly interacted with miR-140-5p via pairing to miR-140-5p. The regulation of circ_CLASP2 overexpression on HG-induced HUVEC dysfunction was mediated by miR-140-5p. Moreover, FBXW7 was a direct target of miR-140-5p, and miR-140-5p regulated HG-induced HUVEC dysfunction via FBXW7. Furthermore, circ_CLASP2 mediated FBXW7 expression through sponging miR-140-5p. Our current study suggested that the overexpression of circ_CLASP2 protected HUVEC from HG-induced dysfunction at least partly through the regulation of the miR-140-5p/FBXW7 axis, highlighting a novel therapeutic approach for the treatment of diabetic-associated vascular injury.


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