Abstract 248: Stabilization of cIAP2 during Postconditioning protects Endothelial Cells from Reperfusion Injury

Circulation ◽  
2007 ◽  
Vol 116 (suppl_16) ◽  
Author(s):  
Krishnaveni Gadiraju ◽  
Frauke V Haertel ◽  
Hans M Piper ◽  
Thomas Noll
Keyword(s):  
Endothelial Cells ◽  
Protective Effect ◽  
Reperfusion Injury ◽  
Intermittent Hypoxia ◽  
Umbilical Vein ◽  
Fold Increase ◽  
Protective Mechanism ◽  
Second Phase ◽  
Induced Apoptosis ◽  
Hypoxia Reoxygenation

Hypoxia-reperfusion causes a perturbance in the complex equilibrium of pro and anti apoptotic mechanisms which ultimately leads to apoptosis in the reperfused myocardium. Postconditioning (intermittent hypoxia at the onset of reperfusion) is a proven strategy to reduce reperfusion injury, however, the mechanisms are largely unknown in endothelial cells. Here we analyze the effect of postconditioning in endothelial cells and hypothesize that the ‘inhibitors of apoptosis proteins’ (IAPs), known as antiapoptotic mediators, are key elements of this protective mechanism. Methods and Results: Exposure of human umbilical vein endothelial cells to severe hypoxia (Po 2 < 2 mmHg) for 2 hrs causes a 2.1±0.5-fold increase in caspase 3 activation (western blot analysis; P<0.05, n=3, for all further parameters) and a 2.3±04-fold increase in apoptosis (annexin V staining) after 24 hrs of reoxygenation. cIAP2 but not cIAP1 is rapidly increased during hypoxia in a biphasic manner. Transcription inhibitor, Actinomycin D (20μg/ml) reveals that the 2.5-fold increase within 5 min of hypoxia (first phase) was independent of transcription, but the 3.1-fold increase after 60 min (second phase) was induced by gene transcription. cIAP2 levels dropped down to basal value with the onset of reperfusion. Importantly, cIAP2 levels could be maintained by postconditioning (3 short periods of intermittent hypoxia, 5 minutes each separated by a 5 minute reoxygenation) which abolished hypoxia-reoxygenation-induced apoptosis. Down regulation of IAP2 by siRNA strategy enhanced hypoxia-reoxygenation-induced apoptosis and diminished the protective effect of postconditioning. Conclusions: The present study shows for the first time that postconditioning can protect endothelial cells against hypoxia-reoxygenation induced apoptosis. This protective effect is conferred by the cIAP2, which is stabilized during hypoxia and could be maintained at an elevated level by postconditioning.

Granulocyte colony-stimulating factor attenuates oxidative stress–induced apoptosis in vascular endothelial cells and exhibits functional and morphologic protective effect in oxygen-induced retinopathy

Blood ◽  
2011 ◽  
Vol 117 (3) ◽  
pp. 1091-1100 ◽  
Author(s):  
Hiroshi Kojima ◽  
Atsushi Otani ◽  
Akio Oishi ◽  
Yukiko Makiyama ◽  
Satoko Nakagawa ◽  
...  
Keyword(s):  
Oxidative Stress ◽  
Endothelial Cells ◽  
Protective Effect ◽  
Vascular Endothelial Cells ◽  
Umbilical Vein ◽  
Granulocyte Colony Stimulating Factor ◽  
Colony Stimulating Factor ◽  
Oxygen Induced Retinopathy ◽  
Induced Apoptosis ◽  
Stimulating Factor

Abstract Granulocyte colony-stimulating factor (G-CSF) is a known hematopoietic glycoprotein, and recent studies have revealed that G-CSF possesses other interesting properties. Oxidative stress is involved in many diseases, such as atherosclerosis, heart failure, myocardial infarction, Alzheimer disease, and diabetic retinopathy. This study was designed to examine whether G-CSF has a protective effect on endothelial cells against oxidative stress and to investigate whether G-CSF has a therapeutic role in ischemic vascular diseases. Expression of G-CSF (P < .01) and G-CSF receptor (P < .05) mRNA in human retinal endothelial cells (HRECs) was significantly up-regulated by oxidative stress. Treatment with 100 ng/mL G-CSF significantly reduced H2O2-induced apoptosis in HRECs from 61.7% to 41.4% (P < .05). Akt was phosphorylated in HRECs by G-CSF addition, and LY294002, a PI3K inhibitor, significantly attenuated the antiapoptotic effect of G-CSF (by 44.1%, P < .05). The rescue effect was also observed in human umbilical vein endothelial cells. In mouse oxygen-induced retinopathy model, G-CSF significantly reduced vascular obliteration (P < .01) and neovascular tuft formation (P < .01). G-CSF treatment also clearly rescued the functional and morphologic deterioration of the neural retina. A possibility of a novel therapeutic strategy for ischemic diseases through attenuating vascular regression using G-CSF was proposed.

The Protective Effect of Tetrahydroxystilbene Glucoside on High Glucose-Induced Injury in Human Umbilical Vein Endothelial Cells through the PI3K/Akt/eNOS Pathway and Regulation of Bcl-2/Bax

2021 ◽  
pp. 1-10
Author(s):  
Jiankun Cui ◽  
Bo Zhang ◽  
Min Gao ◽  
Baohai Liu ◽  
Cong Dai ◽  
...  
Keyword(s):  
Nitric Oxide ◽  
Endothelial Cells ◽  
Protective Effect ◽  
High Glucose ◽  
Umbilical Vein ◽  
Vascular Complications ◽  
Dependent Manner ◽  
Human Umbilical Vein ◽  
Induced Apoptosis ◽  
Umbilical Vein Endothelial Cells

Endothelial dysfunction plays a central role in the patho­genesis of diabetic vascular complications. 2,3,5,4′-tetra­hydroxystilbene-2-O-β-D-glucoside (TSG), an active component extracted from the roots of Polygonum multiflorum Thunb, has been shown to have strong antioxidant and antiapoptotic activities. In the present study, we investigated the protective effect of TSG on apoptosis induced by high glucose in human umbilical vein endothelial cells (HUVECs) and the possible mechanisms. Our data demonstrated that TSG significantly reversed the high glucose-induced decrease in cell viability, suppressed high glucose-induced generation of intracellular reactive oxygen species (ROS), the activity of caspase-3, and decreased the percentage of apoptotic cells in a dose-dependent manner. In addition, we found that TSG not only increased the expression of Bcl-2, while decreasing Bax expression, but also activated phosphorylation of Akt and endothelial nitric oxide synthase (eNOS) with subsequent nitric oxide production and ultimately reduced high glucose-induced apoptosis. However, the antiapoptotic effects of TSG were abrogated by pretreatment of the cells with PI3K inhibitor (LY294002) or eNOS inhibitor N<sup>G</sup>-L-nitro-arginine methyl ester, respectively. These results suggest that TSG inhibits high glucose-induced apoptosis in HUVECs through inhibition of ROS production, activation of the PI3K/Akt/eNOS pathway, and upregulation of the Bcl-2/Bax ratio, and thus may demonstrate significant potential for preventing diabetic cardiovascular complications.

Downregulation of Dicer expression by serum withdrawal sensitizes human endothelial cells to apoptosis

2008 ◽  
Vol 295 (6) ◽  
pp. H2512-H2521 ◽  
Author(s):  
Satoshi Asada ◽  
Tomosaburo Takahashi ◽  
Koji Isodono ◽  
Atsuo Adachi ◽  
Hiroko Imoto ◽  
...  
Keyword(s):  
Endothelial Cells ◽  
Caspase 3 ◽  
Umbilical Vein ◽  
Vascular Endothelial Cell ◽  
Serum Withdrawal ◽  
Tyrosine Kinase 2 ◽  
Nitric Oxide Synthase 3 ◽  
Induced Apoptosis ◽  
Dicer Expression ◽  
Umbilical Vein Endothelial Cells

Although the modulated expression of Dicer is documented upon neoplastic transformation, little is known of the regulation of Dicer expression by environmental stimuli and its roles in the regulation of cellular functions in primary cells. In this study, we found that Dicer expression was downregulated upon serum withdrawal in human umbilical vein endothelial cells (HUVECs). Serum withdrawal induced a time-dependent repression of Dicer expression, which was specifically rescued by vascular endothelial cell growth factor or sphingosine-1-phosphate. When Dicer expression was silenced by short-hairpin RNA against Dicer, the cells were more prone to apoptosis under serum withdrawal, whereas the rate of apoptosis was comparable with control cells in the serum-containing condition. Real-time PCR-based gene expression profiling identified several genes, the expression of which was modulated by Dicer silencing, including adhesion and matrix-related molecules, caspase-3, and nitric oxide synthase 3 (NOS3). Dicer silencing markedly impaired migratory functions without affecting cell adhesion and repressed phosphorylation of focal adhesion kinase and proline-rich tyrosine kinase 2 in adherent HUVECs. Dicer knockdown upregulated caspase-3 and downregulated NOS3 expression, and serum withdrawal indeed increased caspase-3 and decreased NOS3 expression. Furthermore, the overexpression of Dicer in HUVECs resulted in a marked reduction in apoptosis upon serum withdrawal and a decreased caspase-3 and increased NOS3 expression. The inhibition of NOS activity by Nω-nitro-l-arginine methyl ester abrogated the effect of Dicer overexpression to rescue the cells from serum withdrawal-induced apoptosis. These results indicated that serum withdrawal decreases Dicer expression, leading to an increased susceptibility to apoptosis through the regulation of caspase-3 and NOS3 expression.

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