scholarly journals Thymosin β4 regulates endothelial cell function via activating the AKT pathway

2021 ◽  
Vol 62 (4) ◽  
pp. 295-306
Author(s):  
Yong Tang ◽  
Hao Dong ◽  
Wenbin Lu ◽  
Xiaofeng Zhang ◽  
Xiao Shen ◽  
...  

The vascular eendothelial cells are highly heterogeneous and associated with numerous diseases. Thymosin β4 (Tβ4) plays pleiotropic roles in endothelial cell differentiation, migration and angiogenesis. However, the underlying mechanisms played by Tβ4 in the regulation of endothelial cells have not yet been well investigated. In the present study, Tβ4 -GFP adenovirus, transfected into human umbilical vein endothelial cells (HUVECs), and cell morphology were analyzed by fluorescence microscopy. ELISA was used to determine the concentration of Tβ4 expression. Furthermore, the effects of Tβ4 overexpression on HUVECs proliferation, apoptosis and migration were investigated. Real-time quantitative PCR and western blot were conducted to examine mRNA and protein expression in HUVECs with Tβ4 overexpression. Moreover, the underlying molecular mechanism of Tβ4 in HUVECs function was tested through treatment with LY294002, a PI3K/AKT inhibitor. Overexpression of Tβ4 increased the cell ability of HUVECs, and up-regulated the expression of the proliferation markers PCNA and Cyclin D1. In addition, overexpression of Tβ4 reduced HUVECs apoptosis, both under normoxic and hypoxic conditions. Moreover, overexpression of Tβ4 increased the ability of HUVECs to migrate through the membrane and up-regulated levels of MMP-2 and MMP-9. The use of LY294002 decreased the p-AKT (Ser473) level, which was induced by Tβ4 overexpression. Importantly, LY294002 reduced Tβ4-induced HUVECs proliferation and migration. In conclusion, our results suggest that Tβ4 is a major regulator of HUVECs function by activating the AKT signaling pathway.

2015 ◽  
Vol 117 (suppl_1) ◽  
Author(s):  
Qi Sun ◽  
Dongcao Lv ◽  
Qiulian Zhou ◽  
Yihua Bei ◽  
Junjie Xiao

MicroRNAs (miRNAs, miRs), endogenous small non-coding RNA, have been shown to act as essential regulators in angiogenesis which plays important roles in improving blood flow and cardiac function following myocardial infarction. The current study investigated the potential of miR-4260 in endothelial cell function and angiogenesis using human umbilical vein endothelial cells (HUVEC). Our data demonstrated that overexpression of miR-4260 was associated with increased proliferation and migration of HUVEC using EdU incorporation assay (17.25%±1.31 vs 25.78%±1.24 in nc-mimics vs miR-4260 mimics, respectively) and wound healing assay, respectively. While downregulation of miR-4260 inhibited the proliferation (17.90%±1.37 vs 10.66%±1.41 in nc-inhibitor vs miR-4260 inhibitor, respectively) and migration of HUVEC. Furthermore, we found that miR-4260 mimics increased (129.75±3.68 vs 147±3.13 in nc-mimics vs miR-4260 mimics, respectively), while miR-4260 inhibitor decreased the tube formation of HUVECs in vitro (123.25±2.17 vs 92±4.45 in nc-inhibitor vs miR-4260 inhibitor expression, respectively). Our data indicate that miR-4260 contributes to the proliferation, migration and tube formation of endothelial cells, and might be essential regulators for angiogenesis. Further study is needed to investigate the underlying mechanism that mediates the role of miR-4260 in angiogenesis by identifying its putative downstream target genes.


Blood ◽  
2006 ◽  
Vol 107 (3) ◽  
pp. 931-939 ◽  
Author(s):  
Cassin Kimmel Williams ◽  
Ji-Liang Li ◽  
Matilde Murga ◽  
Adrian L. Harris ◽  
Giovanna Tosato

AbstractDelta-like 4 (Dll4), a membrane-bound ligand for Notch1 and Notch4, is selectively expressed in the developing endothelium and in some tumor endothelium, and it is induced by vascular endothelial growth factor (VEGF)-A and hypoxia. Gene targeting studies have shown that Dll4 is required for normal embryonic vascular remodeling, but the mechanisms underlying Dll4 regulatory functions are currently not defined. In this study, we generated primary human endothelial cells that overexpress Dll4 protein to study Dll4 function and mechanism of action. Human umbilical vein endothelial cells retrovirally transduced with Dll4 displayed reduced proliferative and migratory responses selectively to VEGF-A. Expression of VEGF receptor-2, the principal signaling receptor for VEGF-A in endothelial cells, and coreceptor neuropilin-1 was significantly decreased in Dll4-transduced endothelial cells. Consistent with Dll4 signaling through Notch, expression of HEY2, one of the transcription factors that mediates Notch function, was significantly induced in Dll4-overexpressing endothelial cells. The γ-secretase inhibitor L-685458 significantly reconstituted endothelial cell proliferation inhibited by immobilized extracellular Dll4 and reconstituted VEGFR2 expression in Dll4-overerexpressing endothelial cells. These results identify the Notch ligand Dll4 as a selective inhibitor of VEGF-A biologic activities down-regulating 2 VEGF receptors expressed on endothelial cells and raise the possibility that Dll4 may be exploited therapeutically to modulate angiogenesis.


2017 ◽  
Vol 117 (04) ◽  
pp. 734-749 ◽  
Author(s):  
Erika Saretzki ◽  
Franziska Pankratz ◽  
Bianca Engert ◽  
Sebastian Grundmann ◽  
Christoph Bode ◽  
...  

SummaryMicroRNAs are small non-coding RNAs that negatively regulate posttranscriptional gene expression. Several microRNAs have been described to regulate the process of angiogenesis. Previously, we have shown that bone morphogenetic protein 4 (BMP4) increased the proangiogenic activity of endothelial cells. In this project, we now investigated how the pro-angiogenic BMP4 effect is mediated by microRNAs. First, we performed a microRNA array with BMP4-stimulated human umbilical vein endothelial cells (HUVECs). Among the topregulated microRNAs, we detected a decreased expression of miR-494 and increased expression of miR-126–5p. Next, we analysed the canonical Smad and alternative signalling pathways, through which BMP4 would regulate miR-126–5p and miR-494 expression. Furthermore, the functional effect of miR-494 and miR-126–5p on endothelial cells was investigated. MicroRNA-494 overexpression decreased endothelial cell proliferation, migration and sprout formation. Consistently, miR-494 inhibition increased endothelial cell function. As potential miR-494 targets, bFGF and BMP endothelial cell precursorderived regulator (BMPER) were identified and confirmed by western blot. Luciferase assays showed direct miR-494 binding in BMPER 3’UTR. In contrast, miR-126–5p overexpression increased pro-angiogenic endothelial cell behaviour and, accordingly, miR-126–5p inhibition decreased endothelial cell function. As a direct miR-126–5p target we identified the anti-angiogenic thrombospondin-1 which was confirmed by western blot analysis and luciferase assays. In the Matrigel plug assay application of antagomiR-494 increased endothelial cell ingrowth, whereas antagomiR-126–5p treatment decreased cell ingrowth in vivo. Taken together, through differential regulation of the anti-angiomiR-494 and the angiomiR-126–5p by BMP4 both microRNAs contribute to the pro-angiogenic BMP4 effect on endothelial cells.Supplementary Material to this article is available online at www.thrombosis-online.com.


2017 ◽  
Vol 7 (1) ◽  
Author(s):  
Tomohisa Sakaue ◽  
Iori Sakakibara ◽  
Takahiro Uesugi ◽  
Ayako Fujisaki ◽  
Koh-ichi Nakashiro ◽  
...  

Abstract Vascular endothelial cell growth factor receptor 2 (VEGFR2) is an essential receptor for the homeostasis of endothelial cells. In this study, we showed that NEDD8-conjugated Cullin3 (CUL3)-based ubiquitin E3 (UbE3) ligase plays a crucial role in VEGFR2 mRNA expression. Human umbilical vein endothelial cells treated with MLN4924, an inhibitor of NEDD8-activating enzyme, or with CUL3 siRNA drastically lost their response to VEGF due to the intense decrease in VEGFR2 expression. Moreover, speckle-type POZ protein (SPOP) and death-domain associated protein (DAXX) were involved in the CUL3 UbE3 ligase complex as a substrate adaptor and a substrate, respectively. Knockdown of SPOP and CUL3 led to the upregulation of DAXX protein and downregulation of VEGFR2 levels. These levels were inversely correlated with one another. In addition, simultaneous knockdown of SPOP and DAXX completely reversed the downregulation of VEGFR2 levels. Moreover, the CUL3-SPOP-DAXX axis had the same effects on NOTCH1, DLL4 and NRP1 expression. Taken together, these findings suggest that the CUL3-SPOP-DAXX axis plays a very important role in endothelial cell function by targeting key angiogenic regulators.


Circulation ◽  
2020 ◽  
Vol 142 (Suppl_3) ◽  
Author(s):  
Vinicius Garcia ◽  
L. Madden Brewster ◽  
Kelly A Stockelman ◽  
Hannah K Fandl ◽  
Clay Rahaman ◽  
...  

Introduction: Gut microbiota-generated increases in trimethylamine N-oxide (TMAO) has been linked to atherosclerosis and major adverse cardiovascular events. Experimental and clinical studies suggest that TMAO impairs endothelial cell function resulting in a proatherogenic endothelial phenotype. Endothelial microvesicles (EMVs) are anucleate vesicles shed constitutively by the endothelium aiding in cell-to-cell communication, activate repair or defense mechanisms, and/or stimulate immune responses. Under pathologic conditions, however, EMVs are released in greater number and their functional phenotype is more likely to evoke dysfunctional cellular effects. The experimental aims of this study were to determine: 1) if TMAO stimulates EMV release from endothelial cells in vitro ; and 2) the effects of TMAO-generated EMVs on endothelial cell inflammation, apoptosis, autophagy and nitric oxide (NO) production. Methods: Human umbilical vein endothelial cells (HUVECs) were treated with TMAO (100 μmol) for 24 h. EMVs released into the supernatant from cells treated with TMAO or vehicle were isolated and quantified by flow cytometry. Fresh HUVECs were treated with either TMAO-derived or control EMVs for 24 h. Results: EMV release was significantly higher in cells treated with TMAO compared with control (55±3 vs 28±3 EMV/μL). TMAO-generated EMVs induced significantly higher release of interleukin (IL)-6 (33.9±2.6 vs 20.2±1.3 pg/mL) and IL-8 (45.4±2.6 vs 33.1±1.6 pg/mL) and active NF-κB p65 (Ser536) (17.4±1.3 vs 7.7±1.0 AU) expression than control EMVs. TMAO EMVs significantly increased cell expression of apoptotic proteins caspase-9 (198.5±19.4 vs 119.7±11.2 AU) and active caspase-3 (17.7±2.8 vs 11.3±0.7 AU) and markedly depressed eNOS activity (10.6±0.9 vs 6.9±0.6 AU) and NO production (7.7±0.4 vs 5.5±0.6 μmol/L). In addition, cell autophagy was dysregulated by TMAO EMVs; cell expression of Beclin-1 (53.8±6.4 vs 36.6±3.6 AU), p62 (34.0±0.8 vs 16.9±1.2 AU) and LC3BII/LC3BI (15.0±0.1 vs 7.5±0.8 AU) were significantly elevated in cells treated with TMAO vs control EMVs. Conclusions: TMAO-generated EMVs adversely affect major functional characteristics of endothelial cells potentially contributing to the proatherogenic profile of TMAO.


2017 ◽  
Vol 121 (suppl_1) ◽  
Author(s):  
Tyler Bammert ◽  
Jamie Hijmans ◽  
Whitney Reiakvam ◽  
Ma’ayan Levy ◽  
Kelly Stockelman ◽  
...  

Clinical interest in endothelial cell-derived microparticles (EMPs) has increased due to their role in the pathogenesis of vascular disease. Although released by the endothelium, EMPs have autocrine properties that can significantly impact endovascular health. Hyperglycemic conditions, such as diabetes, are known to stimulate EMP release; however, the effects of these glucose-related microparticles on endothelial cell function are not well understood. High glucose concentrations induce endothelial cell apoptosis through a caspase-3-dependent mechanism. The aim of this study was to determine the effect of EMPs derived from a hyperglycemic condition on endothelial cell susceptibility to apoptosis. Human umbilical vein endothelial cells (HUVECs) were cultured (3 rd passage) and plated in 6-well plates at a density of 5.0 x 10 5 cell/condition. Cells were incubated with RPMI 1640 media containing 25mM D-glucose (concentration representing a diabetic glycemic state) or 5mM D-glucose (control, normoglycemic, condition) for 48 h to generate EMPs. EMPs derived from both conditions were pelleted by centrifugation and resuspended in culture media. EMP identification (CD144 + expression) and number was determined by flow cytometry. HUVECs (2 x10 6 cells/condition) were treated with EMPs (2:1 ratio) generated from either the hyperglycemic or normoglycemic conditions for 24 h. Thereafter, cells were treated with staurosporine (1μmol/L) for 3 h at 37°C and biotin-ZVKD-fmk inhibitor for 1 h at 37°C. Intracellular concentration of active caspase-3 was determined by enzyme immune assay. Cellular expression of miR-Let7a, an anti-apoptotic microRNA, was determined by RT-PCR using the ΔΔCT normalized to RNU6. Hyperglycemic EMPs resulted in significant increase in basal (1.5 + 0.1 vs 1.0 + 0.1 ng/mL) and staurosporine-stimulated (2.2 + 0.2 vs 1.4 + 0.1 ng/mL) caspase-3 activity compared with normoglycemic EMPs. Additional, the expression of miR-Let7a was markedly reduced (~140%) in response to hyperglycemic EMPs (0.43 + 0.17 fold vs control). These results demonstrate that hyperglycemic-induced EMPs increase endothelial cell apoptotic susceptibility. This apoptotic effect may be mediated, at least in part, by a reduction in miR-Let7a expression.


2003 ◽  
Vol 90 (08) ◽  
pp. 326-334 ◽  
Author(s):  
Ricardo Gomez ◽  
Roberto Pozner ◽  
Maria Lazzari ◽  
Lina D’Atri ◽  
Soledad Negrotto ◽  
...  

SummaryHematologic involvement is the main feature of Argentine hemorrhagic fever (AHF), an endemo-epidemic disease caused by Junin virus (JV). Since endothelial dysfunction could play a role in AHF-altered hemostasis, we studied human umbilical vein endothelial cell (HUVEC) infection with a virulent (JVv) and a non-virulent (JVa) JV strain. Cells were infected by the two JV variants with no detectable apoptosis or cytopathic effect. Both viral variants up-regulated ICAM-1 and VCAM-1 levels, while von Willebrand factor (VWF) production was decreased. Prostacyclin (PGI2) release and decay accelerating factor (DAF) expression were greater in JVv- than in JVa-infected or control cells. Furthermore, nitric oxide (NO) production and endothelial nitric oxide synthase (eNOS) expression was only raised in JVv-infected supernatants. Significant NO and PGI2 values were also detected in AHF patient sera.These data demonstrate that endothelial cell responses are triggered subsequently by JV infection, suggesting that such alterations play a major role in the pathogenesis of AHF and perhaps in other viral-induced hemorrhagic diseases.


Author(s):  
Steven F. Kemeny ◽  
Alisa Morss Clyne

Endothelial cells line the walls of all blood vessels, where they maintain homeostasis through control of vascular tone, permeability, inflammation, and the growth and regression of blood vessels. Endothelial cells are mechanosensitive to fluid shear stress, elongating and aligning in the flow direction [1–2]. This shape change is driven by rearrangement of the actin cytoskeleton and focal adhesions [2]. Hyperglycemia, a hallmark of diabetes, affects endothelial cell function. High glucose has been shown to increase protein kinase C, formation of glucose-derived advanced glycation end-products, and glucose flux through the aldose reductase pathway within endothelial cells [3]. These changes are thought to be related to increased reactive oxygen species production [4]. While endothelial cell mechanics have been widely studied in healthy conditions, many disease states have yet to be explored. Biochemical alterations related to high glucose may alter endothelial cell mechanics.


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