scholarly journals The ATF site mediates downregulation of the cyclin A gene during contact inhibition in vascular endothelial cells.

1995 ◽  
Vol 15 (6) ◽  
pp. 3266-3272 ◽  
Author(s):  
M Yoshizumi ◽  
C M Hsieh ◽  
F Zhou ◽  
J C Tsai ◽  
C Patterson ◽  
...  
Keyword(s):  
Cell Cycle ◽  
Endothelial Cells ◽  
Vascular Endothelial Cells ◽  
Consensus Sequence ◽  
Critical Role ◽  
Cyclin A ◽  
Contact Inhibition ◽  
Mrna Levels ◽  
Vascular Endothelial ◽  
Nuclear Extracts

Contact inhibition mediates monolayer formation and withdrawal from the cell cycle in vascular endothelial cells. In studying the cyclins--key regulators of the cell cycle--in bovine aortic endothelial cells (BAEC), we found that levels of cyclin A mRNA decreased in confluent BAEC despite the presence of 10% fetal calf serum. We then transfected into BAEC a series of plasmids containing various lengths of the human cyclin A 5' flanking sequence and the luciferase gene. Plasmids containing 3,200, 516, 406, 266, or 133 bp of the human cyclin A promoter directed high luciferase activity in growing but not confluent BAEC. In contrast, a plasmid containing 23 bp of the cyclin A promoter was associated with a 65-fold reduction in activity in growing BAEC, and the promoter activities of this plasmid were identical in both growing and confluent BAEC. Mutation of the activating transcription factor (ATF) consensus sequence at bp -80 to -73 of the cyclin A promoter decreased its activity, indicating the critical role of the ATF site. We identified by gel mobility shift analysis protein complexes that bound to the ATF site in nuclear extracts from growing but not confluent BAEC and identified (with antibodies) ATF-1 as a binding protein in nuclear extracts from growing cells. Also, ATF-1 mRNA levels decreased in confluent BAEC. Taken together, these data suggest that the ATF site and its cognate binding proteins play an important role in the downregulation of cyclin A gene expression during contact inhibition.

scholarly journals Low Shear Stress Upregulates CX3CR1 Expression by Inducing VCAM-1 via the NF-κB Pathway in Vascular Endothelial Cells

2020 ◽  
Vol 78 (3) ◽  
pp. 383-389 ◽  
Author(s):  
Yiwei Zhao ◽  
Peile Ren ◽  
Qiufang Li ◽  
Shafiu Adam Umar ◽  
Tan Yang ◽  
...  
Keyword(s):  
Endothelial Cells ◽  
Shear Stress ◽  
Protein Expression ◽  
Vascular Endothelial Cells ◽  
Critical Role ◽  
Mrna Levels ◽  
Vascular Endothelial ◽  
Low Shear Stress ◽  
Low Shear ◽  
Cx3cr1 Expression

Abstract Atherosclerosis is a significant cause of mortality and morbidity. Studies suggest that the chemokine receptor CX3CR1 plays a critical role in atherogenesis. Shear stress is an important mechanical force that affects blood vessel function. In this study, we investigated the effect of shear stress on CX3CR1 expression in vascular endothelial cells (VECs). First, cells were exposed to different shear stress and then CX3CR1 mRNA and protein were measured by quantitative RT-PCR and western blot analysis, respectively. CX3CR1 gene silencing was used to analyze the molecular mechanisms underlying shear stress-mediated effects on CX3CR1 expression. CX3CR1 mRNA and protein expression were significantly increased with 4.14 dyne/cm2 of shear stress compared with other tested levels of shear stress. We observed a significant increase in CX3CR1 mRNA levels at 2 h and CX3CR1 protein expression at 4 h. CX3CR1-induced VCAM-1 expression in response to low shear stress by activating NF-κB signaling pathway in VECs. Our findings demonstrate that low shear stress increases CX3CR1 expression, which increases VCAM-1 expression due to elevated NF-κB activation. The current study provides evidence of the correlation between shear stress and atherosclerosis mediated by CX3CR1.

scholarly journals Confluence of Vascular Endothelial Cells Induces Cell Cycle Exit by Inhibiting p42/p44 Mitogen-Activated Protein Kinase Activity

1999 ◽  
Vol 19 (4) ◽  
pp. 2763-2772 ◽  
Author(s):  
Francesc Viñals ◽  
Jacques Pouysségur
Keyword(s):  
Cell Cycle ◽  
Endothelial Cells ◽  
Growth Factors ◽  
Vascular Endothelial Cells ◽  
Mitogen Activated Protein Kinase ◽  
Vascular Endothelial ◽  
Cell Cycle Exit ◽  
Mapk Activation ◽  
Mapk Activity ◽  
Mitogen Activated Protein

ABSTRACT Like other cellular models, endothelial cells in cultures stop growing when they reach confluence, even in the presence of growth factors. In this work, we have studied the effect of cellular contact on the activation of p42/p44 mitogen-activated protein kinase (MAPK) by growth factors in mouse vascular endothelial cells. p42/p44 MAPK activation by fetal calf serum or fibroblast growth factor was restrained in confluent cells in comparison with the activity found in sparse cells. Consequently, the induction of c-fos, MAPK phosphatases 1 and 2 (MKP1/2), and cyclin D1 was also restrained in confluent cells. In contrast, the activation of Ras and MEK-1, two upstream activators of the p42/p44 MAPK cascade, was not impaired when cells attained confluence. Sodium orthovanadate, but not okadaic acid, restored p42/p44 MAPK activity in confluent cells. Moreover, lysates from confluent 1G11 cells more effectively inactivated a dually phosphorylated active p42 MAPK than lysates from sparse cells. These results, together with the fact that vanadate-sensitive phosphatase activity was higher in confluent cells, suggest that phosphatases play a role in the down-regulation of p42/p44 MAPK activity. Enforced long-term activation of p42/p44 MAPK by expression of the chimera ΔRaf-1:ER, which activates the p42/p44 MAPK cascade at the level of Raf, enhanced the expression of MKP1/2 and cyclin D1 and, more importantly, restored the reentry of confluent cells into the cell cycle. Therefore, inhibition of p42/p44 MAPK activation by cell-cell contact is a critical step initiating cell cycle exit in vascular endothelial cells.

scholarly journals Shear stress augments mitochondrial ATP generation that triggers ATP release and Ca2+ signaling in vascular endothelial cells

2018 ◽  
Vol 315 (5) ◽  
pp. H1477-H1485 ◽  
Author(s):  
Kimiko Yamamoto ◽  
Hiromi Imamura ◽  
Joji Ando
Keyword(s):  
Endothelial Cells ◽  
Shear Stress ◽  
Vascular Endothelial Cells ◽  
Critical Role ◽  
Atp Release ◽  
Vascular Endothelial ◽  
The Novel ◽  
Caveolin 1 ◽  
Atp Generation

Vascular endothelial cells (ECs) sense and transduce hemodynamic shear stress into intracellular biochemical signals, and Ca2+ signaling plays a critical role in this mechanotransduction, i.e., ECs release ATP in the caveolae in response to shear stress and, in turn, the released ATP activates P2 purinoceptors, which results in an influx into the cells of extracellular Ca2+. However, the mechanism by which the shear stress evokes ATP release remains unclear. Here, we demonstrated that cellular mitochondria play a critical role in this process. Cultured human pulmonary artery ECs were exposed to controlled levels of shear stress in a flow-loading device, and changes in the mitochondrial ATP levels were examined by real-time imaging using a fluorescence resonance energy transfer-based ATP biosensor. Immediately upon exposure of the cells to flow, mitochondrial ATP levels increased, which was both reversible and dependent on the intensity of shear stress. Inhibitors of the mitochondrial electron transport chain and ATP synthase as well as knockdown of caveolin-1, a major structural protein of the caveolae, abolished the shear stress-induced mitochondrial ATP generation, resulting in the loss of ATP release and influx of Ca2+ into the cells. These results suggest the novel role of mitochondria in transducing shear stress into ATP generation: ATP generation leads to ATP release in the caveolae, triggering purinergic Ca2+ signaling. Thus, exposure of ECs to shear stress seems to activate mitochondrial ATP generation through caveola- or caveolin-1-mediated mechanisms. NEW & NOTEWORTHY The mechanism of how vascular endothelial cells sense shear stress generated by blood flow and transduce it into functional responses remains unclear. Real-time imaging of mitochondrial ATP demonstrated the novel role of endothelial mitochondria as mechanosignaling organelles that are able to transduce shear stress into ATP generation, triggering ATP release and purinoceptor-mediated Ca2+ signaling within the cells.

scholarly journals PTPN21 Overexpression Promotes Osteogenic and Adipogenic Differentiation of Bone Marrow-Derived Mesenchymal Stem Cells but Inhibits the Immunosuppressive Function

2019 ◽  
Vol 2019 ◽  
pp. 1-19 ◽  
Author(s):  
Huafang Wang ◽  
Xiaohang Ye ◽  
Haowen Xiao ◽  
Ni Zhu ◽  
Cong Wei ◽  
...  
Keyword(s):  
Cell Cycle ◽  
Stem Cells ◽  
Bone Marrow ◽  
Endothelial Cells ◽  
Mesenchymal Stem Cells ◽  
Tumor Cells ◽  
Vascular Endothelial Cells ◽  
Adipogenic Differentiation ◽  
Target Cells ◽  
Vascular Endothelial

Protein tyrosine phosphatases (PTPs) act as key regulators in various cellular processes such as proliferation, differentiation, and migration. Our previous research demonstrated that non-receptor-typed PTP21 (PTPN21), a member of the PTP family, played a critical role in the proliferation, cell cycle, and chemosensitivity of acute lymphoblastic leukemia cells. However, the role of PTPN21 in the bone marrow microenvironment has not yet been elucidated. In the study, we explored the effects of PTPN21 on human bone marrow-derived mesenchymal stem cells (BM-MSCs) via lentiviral-mediated overexpression and knock-down of PTPN21 in vitro. Overexpressing PTPN21 in BM-MSCs inhibited the proliferation through arresting cell cycle at the G0 phase but rendered them a higher osteogenic and adipogenic differentiation potential. In addition, overexpressing PTPN21 in BM-MSCs increased their senescence levels through upregulation of P21 and P53 and dramatically changed the levels of crosstalk with their typical target cells including immunocytes, tumor cells, and vascular endothelial cells. BM-MSCs overexpressing PTPN21 had an impaired immunosuppressive function and an increased capacity of recruiting tumor cells and vascular endothelial cells in a chemotaxis transwell coculture system. Collectively, our data suggested that PTPN21 acted as a pleiotropic factor in modulating the function of human BM-MSCs.

scholarly journals TR3 Orphan Receptor Is Expressed in Vascular Endothelial Cells and Mediates Cell Cycle Arrest

2003 ◽  
Vol 23 (9) ◽  
pp. 1535-1540 ◽  
Author(s):  
E. Karin Arkenbout ◽  
Maaike van Bragt ◽  
Eric Eldering ◽  
Chris van Bree ◽  
Jos M. Grimbergen ◽  
...  
Keyword(s):  
Cell Cycle ◽  
Endothelial Cells ◽  
Cell Cycle Arrest ◽  
Vascular Endothelial Cells ◽  
Orphan Receptor ◽  
Vascular Endothelial ◽  
Cycle Arrest

scholarly journals Stromal Cell-Derived Factor 1 Protects Brain Vascular Endothelial Cells from Radiation-Induced Brain Damage

Cells ◽  
2019 ◽  
Vol 8 (10) ◽  
pp. 1230 ◽  
Author(s):  
Heo ◽  
Kim ◽  
Woo ◽  
Kim ◽  
Choi ◽  
...  
Keyword(s):  
Endothelial Cells ◽  
Stromal Cell ◽  
Radiation Treatment ◽  
Vascular Endothelial Cells ◽  
Critical Role ◽  
Vascular Endothelial ◽  
Brain Endothelial Cells ◽  
Endothelial Cell Function ◽  
Radiation Induced ◽  
Stromal Cell Derived Factor

Stromal cell-derived factor 1 (SDF-1) and its main receptor, CXC chemokine receptor 4 (CXCR4), play a critical role in endothelial cell function regulation during cardiogenesis, angiogenesis, and reendothelialization after injury. The expression of CXCR4 and SDF-1 in brain endothelial cells decreases due to ionizing radiation treatment and aging. SDF-1 protein treatment in the senescent and radiation-damaged cells reduced several senescence phenotypes, such as decreased cell proliferation, upregulated p53 and p21 expression, and increased senescence-associated beta-galactosidase (SA-β-gal) activity, through CXCR4-dependent signaling. By inhibiting extracellular signal-regulated kinase (ERK) and signal transducer and activator of transcription protein 3 (STAT3), we confirmed that activation of both is important in recovery by SDF-1-related mechanisms. A CXCR4 agonist, ATI2341, protected brain endothelial cells from radiation-induced damage. In irradiation-damaged tissue, ATI2341 treatment inhibited cell death in the villi of the small intestine and decreased SA-β-gal activity in arterial tissue. An ischemic injury experiment revealed no decrease in blood flow by irradiation in ATI2341-administrated mice. ATI2341 treatment specifically affected CXCR4 action in mouse brain vessels and partially restored normal cognitive ability in irradiated mice. These results demonstrate that SDF-1 and ATI2341 may offer potential therapeutic approaches to recover tissues damaged during chemotherapy or radiotherapy, particularly by protecting vascular endothelial cells.

scholarly journals Global Transcriptional Profiling Reveals Novel Autocrine Functions of Interleukin 6 in Human Vascular Endothelial Cells

2020 ◽  
Vol 2020 ◽  
pp. 1-12 ◽  
Author(s):  
Liza U. Ljungberg ◽  
Mulugeta M. Zegeye ◽  
Caroline Kardeby ◽  
Knut Fälker ◽  
Dirk Repsilber ◽  
...  
Keyword(s):  
Cell Cycle ◽  
Endothelial Cells ◽  
Pathway Analysis ◽  
Interleukin 6 ◽  
Vascular Endothelial Cells ◽  
Differential Regulation ◽  
Vascular Endothelial ◽  
Human Endothelial Cells ◽  
Cellular Functions ◽  
Cellular Movement

Background. Interleukin 6 (IL6) is a multifunctional cytokine produced by various cells, including vascular endothelial cells. IL6 has both pro- and non-/anti-inflammatory functions, and the response to IL6 is dependent on whether it acts via the membrane-bound IL6 receptor α (IL6Rα) (classic signaling) or the soluble form of the receptor (transsignaling). As human endothelial cells produce IL6 and at the same time express IL6Rα, we hypothesized that IL6 may have autocrine functions. Methods. Knockdown of IL6 in cultured human endothelial cells was performed using siRNA. Knockdown efficiency was evaluated using ELISA. RNA sequencing was employed to characterize the transcriptional consequence of IL6 knockdown, and Ingenuity Pathway Analysis was used to further explore the functional roles of IL6. Results. Knockdown of IL6 in cultured endothelial cells resulted in a 84-92% reduction in the release of IL6. Knockdown of IL6 resulted in dramatic changes in transcriptional pattern; knockdown of IL6 in the absence of soluble IL6Rα (sIL6Rα) led to differential regulation of 1915 genes, and knockdown of IL6 in the presence of sIL6Rα led to differential regulation of 1967 genes (fold change 1.5, false discovery rate<0.05). Pathway analysis revealed that the autocrine functions of IL6 in human endothelial cells are mainly related to basal cellular functions such as regulation of cell cycle, signaling, and cellular movement. Furthermore, we found that knockdown of IL6 activates functions related to adhesion, binding, and interaction of endothelial cells, which seem to be mediated mainly via STAT3. Conclusion. In this study, a large number of novel genes that are under autocrine regulation by IL6 in human endothelial cells were identified. Overall, our data indicate that IL6 acts in an autocrine manner to regulate basal cellular functions, such as cell cycle regulation, signaling, and cellular movement, and suggests that the autocrine functions of IL6 in human endothelial cells are mediated via IL6 classic signaling.

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