Apoptosis In Human Endothelial Cells Research Articles

The possible role of ursolic acid in Covid-19: A real game changer.

Ursolic acid (UA) is a pentacyclic terpenoid is usually found in the fruit peels and stem bark as secondary metabolites. UA has antiviral, antibacterial, and antiparasitic properties. UA has a wide spectrum of pharmacological activities against different infections. Because of the greatest antiviral and anti-inflammatory properties of UA, so it could be a plausible therapeutic herbal medicine in Covid-19 treatment. Covid-19 is a recent worldwide virulent disease pandemic due to severe acute respiratory coronavirus disease 2 (SARS-CoV-2). The pathogenesis of SARS-CoV-2 infection is related to the direct cytopathic effect and exaggerated immune response by which acute lung injury (ALI) and/or acute respiratory distress syndrome might be developed in critical cases. UA may inhibit main protease of SARS-CoV-2, and inhibits the interface flanked by SARS-CoV-2 viral proteins and its entry point commonly recognized as angiotensin converting enzyme 2 (ACE2). In addition, UA attenuates SARS-CoV-2-induced inflammatory reactions and oxidative stress.Therefore, UA could avert SARS-CoV-2 infection from causing ALI. This opinion proposed that UA might be a potential candidate therapy against Covid-19 and can mitigate post-Covid-19 complications such as lung fibrosis. In this regards, forthcoming studies are reasonable to substantiate the therapeutic role of UA in Covid-19. However, taken into account that Covid-19 is yet to be investigating for further evaluations, therefore, clinical trials are recommended regarding use and dose of UA in Covid-19 treatment, as well as secondary effects.

Colorado tick fever virus induces apoptosis in human endothelial cells to facilitate viral replication

Colorado tick fever virus (CTFV) belongs to the genus Coltivirus of the Reoviridae family, and it is the causative agent of Colorado tick fever. Symptoms of the infection are characterized by sudden biphasic fever, headache, and petechial rash, while severe forms of the disease can include meningoencephalitis, hemorrhagic fever, and death in children. However, the mechanisms underlying CTFV induced pathology and severe complications remain unknown. As CTFV is spread by tick bites and disseminates systemically via hematogenous routes, we performed in vitro analysis examining the interactions between endothelial cells (ECs) and CTFV. Our findings indicate that dermal microvascular ECs, HMEC-1, are susceptible and permissive to CTFV infection. To investigate the role of CTFV infection on endothelial barrier function, we assessed transendothelial electrical resistance (TEER) by xCELLigence and observed a dose-dependent decrease in cell index, indicating increased vascular permeability starting at approximately hour 18 (MOI=1) and hour 26 (MOI=0.1). Since CTFV induced cytopathic effect and increased vascular permeability in HMEC-1 cells, we hypothesized that CTFV causes apoptotic cell death. Our results showed that HMEC-1 cells infected with CTFV at 48 h caused a significant increase in Annexin V staining with reduced viability compared to uninfected cells suggesting CTFV induces apoptotic cell death in human ECs. Electron microscopy also was consistent with apoptotic features, including chromatin condensation and cell blebbing. Furthermore, CTFV induced caspase-3/7 activation at 24 and 48 h post-infection (hpi). The inhibition of caspase activity using Z-VAD-FMK reduced CTFV induced cell death and significantly reduced viral titer. These results indicated that CTFV can infect ECs, exerting direct adverse effects, leading to vascular permeability and cell death. Overall, our data suggest that caspase-mediated apoptosis is a critical mechanism by which CTFV induces disease in the host and enhances viral replication. Future studies will examine the viral and cellular determinants involved in CTFV induced apoptosis in human ECs.

Regulation of docosahexaenoic acid-induced apoptosis of confluent endothelial cells: Contributions of MAPKs and caspases

Endothelial cells, which help to maintain vascular homeostasis, can be functionally modulated by polyunsaturated fatty acids. Previously, we reported that docosahexaenoic acid (DHA) reduced the viability of confluent EA.hy926 endothelial cells with caspase-3 activation. This study therefore examined the molecular mechanism by which DHA affects the viability of confluent cells, with a focus on the interaction between caspase-9, caspase-8, caspase-3, p38 mitogen-activated protein kinase (MAPK) and c-Jun N-terminal kinase (JNK) by Western blotting. Our results revealed that DHA induces apoptosis of confluent cells through both intrinsic and extrinsic pathways, which requires activation of p38 MAPK, and involves activation of JNK, caspase-9, caspase-8 and caspase-3 with the exception that cleavage of caspase-8 was incomplete and truncated BID was not detected at the maximum time (8 h) examined. Apoptosis induced by high levels of DHA in healthy endothelial cells is achieved through positive feedback loops linking these MAPKs to multiple caspases, as well as negative feedback from p38 MAPK to JNK. However, only p38 MAPK is crucial in apoptosis induction in comparison with JNK or any other caspase examined. This study has expanded the knowledge on the molecular mechanism of DHA-induced apoptosis in human endothelial cells and has also implied the differential roles of MAP kinases and caspases in apoptosis.

PM2.5 induces autophagy and apoptosis through endoplasmic reticulum stress in human endothelial cells

Endothelial cells integrally form a crucial interface that maintains homeostasis of the cardiovascular system. As a vulnerable target of PM2.5, the underlying mechanisms of endothelial cell damage have yet to be fully elucidated. In the current study, two types of cell death, including autophagy and apoptosis, and an important organelle of the endoplasmic reticulum (ER) were focalized following PM2.5 exposure. As a result, the internalization of PM2.5 has the ability to induce excess ER stress, which is a crucial step for further autophagy and apoptosis in human endothelial cells, as confirmed by the pre-treatment with the inhibitor of ER stress (4-PBA) which effectively mitigates the apoptosis rate and LC3II expression. Intriguingly, crosstalk between ER stress and autophagy demonstrated that ER stress is probably involved in autophagic events, whereas autophagy has no significant effect on ER stress but confer a protective role against PM2.5-induced endothelial cell apoptosis. Moreover, PM2.5 results in blockage of autophagic flux (failed fusion between autophagosomes and lysosomes), which is detrimental to endothelial cell survival. In conclusion, our findings provide a valuable insight into the relation between autophagy and apoptosis under PM2.5-induced ER stress conditions, where the interplay between them ultimately determines cell fate.

Inhibitory effect of exosomes secreted by human umbilical cord mesenchymal stem cells on apoptosis of oxygen-glucose deprived reoxygenation model of venous endothelial cells

Objective To explore the inhibitory effect of exosomes secreted by human umbilical cord mesenchymal stem cells(HUCMSC) on apoptosis of human umbilical vein endothelial cells(HUVEC) after model group(oxygen-glucose deprivation reoxygenation), and to clarify its possible mechanism. Methods Human umbilical cord mesenchymal stem cells were cultured. The collected cell supernatant was stored in a centrifugal tube. The exosomes secreted by human umbilical cord mesenchymal stem cells were extracted by ultracentrifugation and identified. Human umbilical vein endothelial cells were randomly divided into control group, model group and different concentrations of HUCMSC-EXO(20 μg/ml, 40 μg/ml, 60 μg/ml) treatment groups(adding HUCMSC-EXO into the model group) . The morphological changes of HUVEC cells in each group were observed by inverted phase contrast microscope, and the proliferation inhibition rate of HUVEC in each group was measured by CCK-8 reagent. Western blot was used to detect the expression of apoptosis-related proteins Caspase-3, Bax, Bcl-2 and hypoxia-associated protein hypoxia inducible factor 1α(HIF-1α). Inhibitor(HIF-1α inhibitor) + model group and HUCMSC-EXO + inhibitor + model group were added on the basis of the above experiments. Western blot analysis was performed to observe the effects of HUCMSC-EXO, inhibitor and both of them on HIF-1α and Bax expressions in HUVEC. Results HUCMSC-EXO was successfully extracted and identified. Compared with the control group, the volume of HUVEC in the model group and the HUCMSC-EXO group with different concentrations decreased, became round, connected and evacuated, and the growth state was poor under the inverted phase contrast microscope.CCK-8 detection showed that the cell viability in the HUCMSC-EXO group was significantly higher than that in the model group, the difference was statistically significant (t=9.23, P 0.05)and Bax protein ((0.363±0.069), (0.370±0.064); t=0.18, P>0.05). But both of them were down-regulated compared with the model group (HIF-1α protein (0.919±0.064), Bax protein (0.902±0.071)), the differences were significant( t=13.56, t=13.03, both P<0.05). Conclusion HUCMSC-EXO has a protective effect on OGD/R model of HUVEC, and its mechanism may be related to the down-regulation of HIF-1α expression. Key words: Human umbilical mesenchymal stem cells; Exosomes; Oxygen-glucose deprivation reoxygenation; Human umbilical venous endothelial cells; Apoptosis

Extracellular HtrA2 Induces Apoptosis in Human Umbilical Vein Endothelial Cells.

The serine protease high-temperature-required protein A2 (HtrA2) has been identified as a key intracellular molecule promoting apoptosis in cells during ischemia reperfusion (IR) injury. IR injury in ST-segment elevation myocardial infarction (STEMI) contributes to overall myocardial damage. HtrA2 has further been shown to be significantly increased in the serum of patients with STEMI. In the present pilot study, we use human umbilical vein endothelial cells (HUVECs) to investigate whether extracellular HtrA2 induces apoptosis using Annexin V staining. Furthermore, we examine whether HtrA2 is released extracellularly after staurosporine-induced apoptosis using ELISA. We find that HtrA2 is released upon induction of apoptosis by staurosporine into the cell culture medium. Furthermore, treatment of HUVECs with extracellular HtrA2-induces apoptosis, while the addition of anti-HtrA2 antibodies reduces both HtrA2- and staurosporine-induced endothelial cell apoptosis. In conclusion, we show here that extracellular HtrA2 induces apoptosis in human endothelial cells, although the exact molecular mechanisms have to be investigated in future.

Protective effect of cycloartenyl ferulate on lipopolysaccharide induced endothelial cell apoptosis and its mechanism

Objective To investigate the effect of cycloartenyl ferulate (CF) on lipopolysaccharide (LPS)-induced apoptosis in human umbilical vein endothelial cells (HUVEC), and to explore its relative mechanism. Methods Human umbilical vein endothelial cells were cultured in vitro, and the experiment was divided into the normal group, CF group, LPS group, and LPS+CF groups at different concentrations. After the corresponding treatment of cells in each group, the cell viability and apoptosis of each group were tested by the cell counter Kit-8 (CCK-8) assay and TdT-mediated dUTP nick end labeling (TUNEL) assay. The protein expression of Bax, Bcl-2, caspase-3 and the effect of CF on the protein expression of Nrf2/HO-1 pathway were determined by Western blot. One-way ANOVA were performed in multigroup mean comparison, LSD-t test was used to compare the mean values of two samples, and P<0.05 was considered statistically significant. Results Compared with the LPS group, the survival rate of HUVECs cells in the CF group was significantly increased with different doses, and the survival rate increased significantly in the 320 μmol/L CF group [(69.85±1.2)% vs ( 100.2±1.824)%, P< 0.01]. TUNEL staining showed that compared with the LPS group, the number of apoptotic positive cells in the 320 μmol/L CF group was significantly reduced [(27.33 ± 3.40) vs (11.67 ± 2.04), P<0.01]. Compared with the LPS group, Bcl-2 protein expression level was significantly increased in the CF group at different doses (P<0.01), caspase-3 and Bax protein expression were significantly decreased (P<0.01). Nrf2 protein expression level increased significantly (P<0.01), and HO-1 protein level increased significantly (P<0.01). Conclusion CF can alleviate LPS-induced apoptosis of HUVEC, which may be related to the increase of bcl-2 expression, the decrease of caspase-3 and Bax protein expression and the activation of Nrf2/ HO-1 signaling pathway. Key words: Cycloartenyl ferulate; Lipopolysaccharide; Vascular endothelial cells; Apoptosis; Nrf2/HO-1 signaling pathway

MicroRNA-34a promotes hypertension-induced vascular injury by targeting B-lymphocytoma-2

Objective To investigate the level of microRNA (miRNA, miR)-34a in serum of hypertensive patients and its effect on proliferation and apoptosis of human umbilical vein endothelial cells (HUVECs) by targeting B cell lymphoma/leukemia-2 (bcl-2), and clarify the underlying mechanism of hypertension-induced vascular injury. Methods Real-time quantitative polymerase chain reaction (qPCR) was used to detect the level of miR-34a in serum of 98 hypertensive patients and 65 healthy controls; the potential targets of miR-34a was predicted by TargetScan; the interaction between miR-34a and bcl-2 was measured by dual luciferase reporter assay, western blot and qPCR; the effect of miR-34a on proliferation and apoptosis of HUVECs was detected by methyl thiazol tetrazolium (MTT) and flow cytometry. Results The level of miR-34a in serum of 98 hypertensive patients (2.432±0.201) was significantly higher than that of 65 healthy controls (0.996±0.112, P 0.05). The protein and mRNA level of bcl-2 in HUVECs after overexpressing miR-34a (0.403±0.041, 0.206±0.018) decreased significantly than that in Blank group (1.000±0.098, 1.000±0.067) and miR-NC group (0.996±0.087, 1.012±0.049). The proliferation of HUVECs after overexpressing miR-34a (48 h: 0.269±0.021, 72 h: 0.324±0.028) decreased significantly than that of the Blank group (48 h: 0.324±0.025, 72 h: 0.458±0.044) and miR-NC group (48 h: 0.335±0.028, 72 h: 0.469±0.051, P<0.05), and apoptosis (23.54±2.65) was significantly higher than that of Blank (6.45±0.42) and miR-NC (7.32±0.54, P<0.05). Conclusion MiR-34a is overexpressed in serum of hypertensive patients. Overexpressing miR-34a can inhibit proliferation of HUVECs by targeting bcl-2 expression, which may be one of the potential mechanisms of vascular injury in hypertensive patients and provide experimental basis for using miR-34a as a new target to diagnose and treat hypertension in the future. Key words: MicroRNA-34a; B cell lymphoma/leukemia-2; Hypertension; Vascular injury

3D matrix-embedding inhibits cycloheximide-mediated sensitization to TNF-alpha-induced apoptosis of human endothelial cells.

The programmed form of cell death (apoptosis) is essential for normal development of multicellular organisms. Dysregulation of apoptosis has been linked with embryonal death and is involved in the pathophysiology of various diseases. Others and we previously demonstrated endothelial biology being intertwined with biochemical and structural composition of the subendothelial basement membrane. We now demonstrate that a three-dimensional growing environment significantly shields endothelial cells from cytokine-induced apoptosis. Detailed analysis reveals differences in intracellular signaling pathways in naive endothelial cells and cytokine-stimulated endothelial cells when cells are grown within a three-dimensional collagen-based matrix compared to cells grown on two-dimensional tissue culture plates. Main findings are significantly reduced p53 expression and level of p38-phosphorylation in three-dimensional grown endothelial cells. Despite similar concentrations of focal adhesion kinase, three-dimensional matrix-embedded endothelial cells express significantly less tyrosine-phosphorylated focal adhesion kinase. Pretreatment with antibodies against integrin αv β3 partially reversed the protective effect of three-dimensional matrix-embedding on endothelial apoptosis. Our findings provide detailed insights into the mechanisms of endothelial apoptosis with respect to the spatial matrix environment. These results enhance our understanding of endothelial biology and may otherwise help in the design of tissue-engineered materials. Furthermore, findings on focal adhesion kinase phosphorylation might enhance our understanding of clinical studies with tyrosine kinase inhibitors.

Activation of Nrf2-mediated anti-oxidant genes by antrodin C prevents hyperglycemia-induced senescence and apoptosis in human endothelial cells.

In the present study, we investigated the effects of antrodin C (ADC), a maleimide derivative isolated from mycelia of Antrodia cinnamomea, on high glucose (HG, 30 mM)-accelerated endothelial dysfunction in vitro. HG-induced cytotoxicity in human umbilical vein endothelial cells (HUVECs) was significantly ameliorated by ADC. In addition, treatment with ADC significantly prevented HG-induced senescence, growth arrest at the G1-S transition phase and apoptosis in HUVECs. Moreover, the increased level of intracellular reactive oxygen species (ROS) under HG condition was significantly ameliorated by ADC. Further analysis revealed that ADC-mediated anti-oxidant effects were due to up-regulation of cellular anti-oxidant genes, such as HO-1 and NQO-1 via promotion of the transcriptional activity of Nrf2, which was further confirmed by the failure of ADC to protect HUVECs from HG-induced dysfunction under HO-1 inhibition or Nrf2 silencing. Furthermore, hyperosmotic glucose (HOG, 60 mM)-induced uncontrolled production of ROS, rapid apoptotic cell death and HUVEC injury were significantly prevented by ADC, whereas these preventive effects were barely observed in HO-1 inhibited or Nrf2 silenced cells. Taken together, these results suggest that ADC may represent a promising intervention in diabetic-associated cardiovascular diseases by activating the Nrf2-dependent cellular anti-oxidant defense system.

Novel role for p56/Lck in regulation of endothelial cell survival and angiogenesis

Previous studies have demonstrated that cleaved high-molecular-weight kininogen (HKa) induces endothelial apoptosis and inhibits angiogenesis and have suggested that this occurs through inhibition of Src family kinases. This study assessed the role of tyrosine-protein kinase Lck (p56/Lck) in this pathway. We analyzed early events leading to apoptosis of human endothelial cells exposed to HKa. The role of p56/Lck was investigated using short interfering (si) RNA knockdown and lentivirus expression in assays of endothelial tube formation, sprouting of neovessels from murine aorta, and angiogenesis in Matrigel plugs. HKa stimulated expression and phosphorylation of p56/Lck. siRNA knockdown of p56/Lck promoted endothelial proliferation and blocked HKa-induced apoptosis and activation of p53, Bax, and Bak. Lentivirus expression of p56/Lck in endothelial cells induced apoptosis and blocked tube formation. Expression of p56/Lck in murine aortic rings blocked sprouting angiogenesis. Lentivirus expressing p56/Lck blocked angiogenesis in Matrigel plugs, while p56/Lck short hairpin RNA inhibited the antiangiogenic effect of HKa. Scrambled siRNAs and empty lentiviral vectors were used in all experiments. Apoptosis of proliferating endothelial cells and inhibition of angiogenesis by HKa requires p56/Lck. This suggests a novel role for p56/Lck in regulation of endothelial cell survival and angiogenesis.-Betapudi, V., Shukla, M., Alluri, R., Merkulov, S., McCrae, K. R. Novel role for p56/Lck in regulation of endothelial cell survival and angiogenesis.

Concentration Polarization of Ox-LDL and Its Effect on Cell Proliferation and Apoptosis in Human Endothelial Cells

Concentration Polarization of Ox-LDL and Its Effect on Cell Proliferation and Apoptosis in Human Endothelial Cells

Effect of Glucagon-like Peptide-1 on High-Glucose-induced Oxidative Stress and Cell Apoptosis in Human Endothelial Cells and Its Underlying Mechanism.

Glucagon-like peptide-1 (GLP-1) has been demonstrated to play an important role in type 2 diabetes mellitus, leading to cardiovascular diseases. This study aimed to examine the GLP-1 regulation of high-glucose-induced oxidative stress and cell apoptosis in human umbilical vein endothelial cells (HUVECs) and its underlying mechanism. HUVECs were isolated from healthy umbilical cords and cultured. GLP-1 and the GLP-1R antagonist, exendin (9-39), were used to pretreat the cells. The expression of NADPH oxidase subunits gp91 and p22 messenger RNA was detected by real-time quantitative polymerase chain reaction. Reactive oxygen species production was detected with flow cytometry and fluorescence microscopy. Lucigenin assay was used to measure the NADPH oxidase activity. The terminal deoxynucleotidyltransferase-mediated dUTP nick end labeling assay was used to investigate endothelial cell apoptosis. Apoptosis proteins were detected by immunoblotting. GLP-1 decreased high-glucose-induced oxidative stress, the expression of gp91 and p22phox messenger RNAs, and NADPH oxidase activation. Exendin (9-39) antagonized the effects of GLP-1 on high-glucose-induced oxidative stress. GLP-1 also increased HUVEC's high-glucose-induced proliferation and inhibited apoptosis. GLP-1 inhibited high-glucose-induced oxidative stress and cell apoptosis in HUVECs through GLP-1R-dependent and GLP-1 (9-36)-related pathways. GLP-1 suppressed high-glucose-induced oxidative stress and consequently may have an antiatherosclerosis effect on diabetes mellitus patients.

Tribbles homolog 3 is induced by high glucose and associated with apoptosis in human endothelial cells.

Tribbles homolog 3 (TRIB3) is an intracellular kinase-like molecule that modifies cellular survival and metabolism. The present study aimed to investigate the function of TRIB3 regulation in the process of high glucose-induced apoptosis in endothelial cells, with the aim of identifying a novel intervention target for the prevention and treatment of diabetes mellitus. Human umbilical vein endothelial cells (HUVECs) grown in medium with various concentrations of glucose (5.5, 10, 20, 30 and 40 mmol/l) were assessed for mRNA expression of TRIB1, TRIB2 and TRIB3 using reverse transcription quantitative polymerase chain reaction. In addition, protein expression of TRIB3 was examined using western blot analysis. Immunofluorescence staining was performed in order to determine the distribution and localization of TRIB3 in HUVECs. Furthermore, cells grown in normal (5.5 mmol/l) or high glucose (HG; 30 mmol/l) medium were subjected to TRIB3 inhibition through small interfering (si)RNA knockdown. These cells were then examined in order to determine whether TRIB3 upregulation was associated with endothelial cell apoptosis. HUVECs treated with 30 and 40 mmol/l glucose for 48 h and 72 h showed significantly lower survival rates compared with those treated with normal glucose levels. In addition, slight but not significant increases in TRIB1 and TRIB2 mRNA expression were observed in HUVECs incubated with various concentrations of glucose for different durations. By contrast, TRIB3 mRNA expression was increased 7.2-fold following incubation with HG. Western blot analysis revealed a 5.44-fold increase in TRIB3 protein levels in cells grown in HG medium for 24 h compared with those grown in normal medium. Immunostaining assays revealed a markedly higher and well-defined nucleolar fluorescence intensity for TRIB3 expression at 24 h in HG medium compared with that of the control group. Furthermore, the apoptotic rate of HG-treated TRIB3 siRNA-transfected HUVECs was significantly increased compared with that of those transfected with control siRNA In conclusion, the results of the present study suggested that TRIB3 was associated with high glucose-induced HUVECs apoptosis, which was attenuated following transfection with TRIB3 siRNA.

Influenza virus aggravates the ox-LDL-induced apoptosis of human endothelial cells via promoting p53 signaling.

Oxidized low-density lipoprotein (ox-LDL) is well recognized to play a key role in the development of atherosclerosis. And influenza virus infection has been also recognized to promote the atherosclerosis onset and progressing. However, little is known about the mechanism into it. In present study, we investigated the infection of A/Porto Rico/8/1934 (H1N1) (PR8) influenza virus in human endothelial Eahy926 cells, and determined the induction of apoptosis by the virus infection in the cell. Then we investigated the apoptosis induced by ox-LDL in Eahy926 cells, determined the influence of influenza virus infection on the ox-LDL-induced apoptosis in Eahy926 cells. Results demonstrated that PR8 virus infected human endothelial Eahy926 cells, forming plaques and replicated efficiently in the cell. And the virus infection promoted apoptosis in the cell, upregulated cytchrome c release, activated caspase 3. And what's more, we found that combined PR8 virus infection and ox-LDL treatment promoted higher level of apoptosis and higher level of the activation of apoptosis-associated molecules. Further examination indicated that the p53 signaling was more significantly promoted by both treatments. Therefore, present study confirmed that influenza virus aggravated the ox-LDL-induced apoptosis of human endothelial Eahy926 cells via promoting p53 signaling.

The effects of interleukin 17 on the proliferation, migration and apoptosis of human retinal vascular endothelial cells

Objective To address the effect and mechanism of interleukin 17 (IL-17) on the proliferation, migration and apoptosis of human retinal vascular endothelial cells (HREC). Methods IL-17 receptor (IL-17R) mRNA and protein expression in human retinal vascular endothelial cells (HREC) were quantified by reverse transcription polymerase chain reaction (RT-PCR) and Western blot. Cell proliferation of HREC was examined using CCK-8 assay in the presence of different concentrations of IL-17. Cell migration of HREC was detected using wound scratch assay. Flow cytometry was used to test the effect of IL-17 on the apoptosis of HREC. The effects of IL-17 on HREC expression of basic fibroblast growth factor (bFGF), Caspase-3 and thrombospondin-1 (TSP-1) were quantified by reverse transcriptase polymerase chain reaction (RT-PCR). The effect of IL-17 on HREC expression of Caspase-3 was examined using Western blot. Results IL-17 receptor (IL-17R) expressed in HREC as quantified by RT-PCR and Western blot. The proliferation of HREC in the presence of IL-17 was promoted in a dosage-dependent manner (t=-3.235, -6.276; P=0.032, 0.000). Wound scratch assay showed a significant increase in the migrated distance of HREC with IL-17 stimulation under the concentration of 100 μg/L(t=-3.551, -2.849; P=0.006, 0.019), 200 μg/L(t=-10.347, -4.519; P=0.000, 0.001) and 500 μg/L (t=-3.541, -2.607; P=0.008, 0.036). The intervention of 200 μg/L IL-17 can effectively inhibit the apoptosis of HREC, compared with the control group using flow cytometry (t=5.682, P=0.047). RT-PCR results showed that IL-17 can promote the expression of bFGF and inhibit the expression of Caspase-3 and TSP-1. Western blot result also showed that IL-17 can suppress the protein expression of Caspase-3. Conclusion The mechanism of IL-17 promoting proliferation, migration but suppress apoptosis of HREC may via regulating the expression of bFGF and Caspase-3. Key words: Interleukin-17; Endothelial cells/pathophysiology; Cell proliferation; Cell movement; Apoptosis

Endothelial modulation of ICAM-1, CD36 and inflammatory cytokines IL-6, IL-8 and MCP-1 by P. falciparum-infected erythrocytes.

Endothelial modulation of ICAM-1, CD36 and inflammatory cytokines IL-6, IL-8 and MCP-1 by P. falciparum-infected erythrocytes.

LR-90 prevents methylglyoxal-induced oxidative stress and apoptosis in human endothelial cells

Methylglyoxal (MGO) is a highly reactive dicarbonyl compound known to induce cellular injury and cytoxicity, including apoptosis in vascular cells. Vascular endothelial cell apoptosis has been implicated in the pathophysiology and progression of atherosclerosis. We investigated whether the advanced glycation end-product inhibitor LR-90 could prevent MGO-induced apoptosis in human umbilical vascular endothelial cells (HUVECs). HUVECs were pre-treated with LR-90 and then stimulated with MGO. Cell morphology, cytotoxicity and apoptosis were evaluated by light microscopy, MTT assay, and Annexin V-FITC and propidium iodide double staining, respectively. Levels of Bax, Bcl-2, cytochrome c, mitogen-activated protein kinases (MAPKs) and caspase activities were assessed by Western blotting. Reactive oxygen species (ROS) generation and mitochondrial membrane potential (MMP) were measured with fluorescent probes. LR-90 dose-dependently prevented MGO-associated HUVEC cytotoxicity and apoptotic biochemical changes such as loss of MMP, increased Bax/Bcl-2 protein ratio, mitochondrial cytochrome c release and activation of caspase-3 and 9. Additionally, LR-90 blocked intracellular ROS formation and MAPK (p44/p42, p38, JNK) activation, though the latter seem to be not directly involved in MGO-induced HUVEC apoptosis. LR-90 prevents MGO-induced HUVEC apoptosis by inhibiting ROS and associated mitochondrial-dependent apoptotic signaling cascades, suggesting that LR-90 possess cytoprotective ability which could be beneficial in prevention of diabetic related-atherosclerosis.

A phosphoramidon-sensitive metalloprotease induces apoptosis of human endothelial cells by Group B Streptococcus

We explored Group B Streptococcus (GBS)-induced apoptosis in human umbilical vein endothelial cells (HUVEC) and the role of phosphoramidon, a zinc metalloprotease inhibitor, in this process. GBS 90186 strain (serotype V, a blood isolate) and concentrated supernatant (CS) were used to investigate the viability and morphological alterations in HUVEC by Trypan blue uptake, electrophoresis in 2 % agarose gel and scanning electron microscopy assays. Apoptosis before and after phosphoramidon-treatment were verified by flow cytometry using annexin V-FITC labeling. Differences were considered significant when P < 0.05 using unpaired Student's t test. GBS and CS induced HUVEC death by apoptosis (76.5 and 32 %, respectively) with an increasing pro-apoptotic Bax expression and decreasing anti-apoptotic Bcl-2 expression. Caspase-3 was activated during GBS-induced endothelial apoptosis. Phosphoramidon reduced 89.3 and 100 % of GBS and CS cell death by apoptosis, respectively. Some GBS strains may induce cell death by apoptosis with involvement of metalloproteases and signaling through the intrinsic pathway of apoptosis, which may contribute to GBS survival during sepsis of adults and neonates.

TcpC induces apoptosis of human vascular endothelial cells and its mechanisms

To investigate the effects of TcpC on human umbilical vascular endothelial cells (HUVECs) and its mechanisms. HUVECs were co-cultured with TcpC secreting wild-type E. coli strain CFT073 (TcpC(wt)) or tcpc gene-deleted CFT073 mutant strain (TcpC(mut)) in transwell system,respectively. Apoptosis of HUVECs was analyzed by Annexin-V/PI double staining. Mitochondrial membrane depolarization was detected by JC-1 staining. Expression of apoptosis-related proteins in HUVECs was determined by Western blot. HUVECs showed morphological changes after co-cultured with TcpC(wt) for 24 h: the cells became detached and cell debris increased,and cell number was also decreased when compared to HUVECs co-cultured with TcpC(mut). The apoptosis of HUVEC cells co-cultured with TcpC(wt) for 24 h significantly increased,compared to that of control group and TcpC(mut) group (60.1% 9.7% compared with 9.0% 1.3% and 16.9% 0.4%,respectively, P<0.05); meanwhile the mitochondrial depolarization of HUVECs co-cultured with TcpC(wt) was significantly increased,compared to that in control and TcpC(mut) groups (64.5% 0.9% compared with 14.5% 2.1% and 15.6% 3.3%, respectively,P<0.05). Cleavage of PARP and inhibition of Mcl-1 and XIAP expression were seen in HUVECs co-cultured with TcpC(wt),but not in groups of control and TcpC(mut). TcpC secreted from CFT073 can induce apoptosis of HUVECs through mitochondrial pathway, in which PARP is cleaved and Mcl-1 and XIAP expressions are inhibited.