Objective To investigate the effects of ROCK-siRNA transfection on endothelial cell senescence and endothelial microparticles (EMPs) induced by angiotensin II (Ang II). Methods Human umbilical vein endothelial cells (HUVECs) were treated with Ang II (1.0 μmo/L) to induce cellular senescence models, followed by transfection with ROCK-siRNA. The cells were divided into four groups: control group, model group, negative transfection control group (Ang II combined with NC-siRNA), and ROCK-siRNA transfection group (Ang II combined with ROCK-siRNA). Cellular senescence was assessed by SA-β-Gal staining. EMP levels in cell supernatants and intracellular reactive oxygen species (ROS) levels were assessed using flow cytometry. The expression levels of silenced information regulator 1(SIRT1) and p53 protein in each group were analyzed by Western blotting. Results Following ROCK-siRNA transfection, the number of senescent cells induced by Ang II was significantly reduced, accompanied by decreased CD31⁺ EMP levels and suppressed intracellular ROS levels. Meanwhile, the expression levels of SIRT1 were up-regulated, while the expression levels of p53 were down-regulated. Conclusion Silencing ROCK expression suppresses EMP release, reduces ROS generation, regulates the expression of SIRT1 and p53, and ultimately attenuates Ang II-induced endothelial cell senescence.
Humans ; Angiotensin II/pharmacology* ; Cellular Senescence/genetics* ; Human Umbilical Vein Endothelial Cells/cytology* ; RNA, Small Interfering/metabolism* ; Reactive Oxygen Species/metabolism* ; Sirtuin 1/genetics* ; Transfection ; Tumor Suppressor Protein p53/genetics* ; Cell-Derived Microparticles/drug effects* ; rho-Associated Kinases/metabolism* ; Endothelial Cells/metabolism* ; Cells, Cultured

OBJECTIVES: To investigate the effects of Astragaloside IV (AST) on diastolic function of rat thoracic aorta rings which was injured by microvesicles derived from hypoxia/reoxygenation (H/R)-treated human umbilical vein endothelial cells (HUVECs), and the mechanism of AST. METHODS: H/R-induced endothelial microvesicles (H/R-EMVs) were generated from cultured HUVECs under the condition of hypoxia for 12 hour/Reoxygenation for 4 hour, H/R-EMVs were stored in D-Hank's solution. Male Wistar rats were underwent thoracotomy, the thoracic aorta with intact endothelium were carefully removed and cut into 3~4 mm rings. The experiment was divided into six groups. H/R-EMVs group:thoracic aortic rings of rats were incubated in culture medium and treated with H/R-EMVs in a final concentration of 10g/ml; different doses of AST groups:thoracic aortic rings of rats were treated with 10, 20, 40, 60 mg/L AST co-incubated with 10g/ml H/R-EMVs respectively; control group were treated with the same volume of D-Hank's solution. Duration of incubation was 4 h, each group was tested in five replicate aortic rings. Effects of AST on endothelium-dependent relaxation were detected. The production of nitric oxide (NO) and the level of endothelial NO synthase (eNOS), phosphorylated eNOS (p-eNOS, Ser-1177), serine/threonine kinase (Akt), phosphorylated Akt (p-Akt, Ser-473), extracellular regulated protein kinases (ERK1/2) and phosphorylated ERK1/2 (p-ERK1/2, Thr202/Tyr204) of rat thoracic aortic rings were detected. RESULTS: Teng/ml H/R-EMVs could impaire the relaxation of rat thoracic aortic rings significantly (<0.01). Compared with H/R-EMVs group, relaxation of rat thoracic aortic rings was increased by 20, 40 and 60 mg/L AST in a concentration-dependent manner (<0.01), the level of NO production was also enhanced (<0.05, <0.01). The level of t-eNOS, t-Akt and ERK1/2 was not changed, but the level of p-eNOS, p-Akt and p-ERK1/2 increased by the treatment with AST (<0.01). CONCLUSIONS AST could effectively ameliorate endotheliumdependent relaxation of rat thoracic aortic rings impaired by H/R-EMVs in a concentration-dependent manner, the mechanism might involve the increase in production of NO, and the protein level of p-eNOS, p-Akt and p-ERK1/2.
Animals ; Aorta, Thoracic ; drug effects ; Cell-Derived Microparticles ; pathology ; Human Umbilical Vein Endothelial Cells ; Humans ; In Vitro Techniques ; MAP Kinase Signaling System ; Male ; Nitric Oxide ; metabolism ; Nitric Oxide Synthase Type III ; metabolism ; Proto-Oncogene Proteins c-akt ; metabolism ; Rats ; Rats, Wistar ; Saponins ; pharmacology ; Triterpenes ; pharmacology ; Vasodilation

MicroRNAs (miRNAs) are a class of noncoding RNAs that regulates target gene expression at posttranscriptional level, leading to further biological functions. We have demonstrated that microvesicles (MVs) can deliver miRNAs into target cells as a novel way of intercellular communication. It is reported that in central nervous system, glial cells release MVs, which modulate neuronal function in normal condition. To elucidate the potential role of glial MVs in disease, we evaluated the effects of secreted astrocytic MVs on stress condition. Our results demonstrated that after Lipopolysaccharide (LPS) stimulation, astrocytes released shedding vesicles (SVs) that enhanced vulnerability of dopaminergic neurons to neurotoxin. Further investigation showed that increased astrocytic miR-34a in SVs was involved in this progress via targeting anti-apoptotic protein Bcl-2 in dopaminergic neurons. We also found that inhibition of astrocytic miR-34a after LPS stimulation can postpone dopaminergic neuron loss under neurotoxin stress. These data revealed a novel mechanism underlying astrocyte-neuron interaction in disease.
Animals ; Astrocytes ; cytology ; drug effects ; metabolism ; Cell Line, Tumor ; Cell Survival ; drug effects ; Cell-Derived Microparticles ; metabolism ; Disease Models, Animal ; Dopaminergic Neurons ; drug effects ; pathology ; Down-Regulation ; drug effects ; Humans ; Lipopolysaccharides ; pharmacology ; MicroRNAs ; metabolism ; Neurotoxins ; toxicity ; Oxidopamine ; Proto-Oncogene Proteins c-bcl-2 ; metabolism ; Rats ; Stress, Physiological ; drug effects

BACKGROUNDEndothelial cells derived microRNAs can be detected in plasma and serum and there is evidence that inflammatory disease states may affect the levels of circulating microRNAs. However, there is no direct proof that inflammation induces endothelial cells to release microRNAs into circulation. This study aimed to explore whether inflammation could induce endothelial cells to release microRNAs into circulation and to investigate whether these released microRNAs derived from endothelial cells were transported in microparticles.

METHODSMicroparticles were isolated from human atherosclerotic plaques with an active inflammatory phenotype and normal vascular tissue. Flow cytometry and real-time PCR were used to detect the levels of microparticles and microRNAs. Human umbilical vein endothelial cells (HUVEC) was treated with tumour necrosis factor a (TNF-α, 10 ng/ml) for 24 hours, and then HUVEC and the culture medium were respectively collected.

RESULTSBy comparing microparticles isolated from human atherosclerotic plaques with an active inflammatory phenotype (n = 9) and those from normal vascular tissues (n = 9), we found levels of annexin V(+) microparticles and annexin V(+) CD144(+) microparticles were significantly increased in plaques and angiogenesis associated microRNAs (106b, 25, 92a and 21) were also significantly increased in microparticles from plaques. After exposure to TNF-α at a concentration of 10 ng/ml (TNF-α group, n = 3) or DMEM (control group, n = 3) for 24 hours, counts of microparticles and expressions of microRNAs 106b, 25, 92a and 21 in microparticles isolated from medium significantly increased. However, there were no differences in the intracellular levels of microRNAs 25, 92a or 21 isolated from HUVEC between TNF-α group and control group, while microRNA 106b decreased in TNF-α group.

CONCLUSIONInflammation could induce endothelial cells to release angiogenesis associated microRNAs into circulation, causing higher levels of circulating endothelial cells derived microRNAs in atherosclerosis.

Annexin A5 ; metabolism ; Cell-Derived Microparticles ; metabolism ; Cells, Cultured ; Gene Expression Regulation ; drug effects ; Human Umbilical Vein Endothelial Cells ; drug effects ; metabolism ; Humans ; Inflammation ; genetics ; immunology ; MicroRNAs ; genetics ; metabolism ; Real-Time Polymerase Chain Reaction ; Tumor Necrosis Factor-alpha ; pharmacology

OBJECTIVETo explore the correlation between circulating endothelial microparticles (EMPs) and flow-mediated dialation (FMD) in patients with coronary artery disease (CAD), and investigate the role of NADPH oxidase in endothelial cell dysfunction caused by EMPs.

METHODSFifteen patients with CAD and 15 at high risks of CAD were tested for the level of EMPs and FMD and other biochemical indices, and the correlation between the indices were analyzed. EMPs obtained from cultured human umbilical vein endothelial cells (HUVECs) were phenotyped and used to stimulate the HUVECs, whose ROS and NO production was tested.

RESULTSEndothelial dilation function could be damaged by circulating EMPs in CAD patients. Dysfunction of HUVECs caused by 10(5)/ml EMPs could be reversed by pretreatment with 20 micromol/L apocynin, a NADPH oxidase inhibitor.

CONCLUSIONEndothelial dialation function of the endothelial cells can be damaged by circulating EMPs in patients with CAD in association with NADPH oxidase activation.

Adult ; Aged ; Cell-Derived Microparticles ; drug effects ; metabolism ; Cells, Cultured ; Coronary Disease ; pathology ; Endothelial Cells ; cytology ; drug effects ; physiology ; Female ; Humans ; Male ; Middle Aged ; NADPH Oxidases ; metabolism ; Umbilical Veins ; cytology

This study was purposed to investigate the angiogenesis effect of platelet-derived membrane microparticles (PMPs) in chick chorioallantoic membranes (CAM). Thrombin were adopted to activate the platelets and then PMPs were obtained. PMPs were isolated by high speed centrifugation. Flow cytometry (FCM) was adopted to evaluate the efficiency of thrombin to produce PMPs and BCA method was adopted to evaluate the content of PMPs. PMPs were put into CAM and the effects of PMPs on angiogenesis in CAM were observed. The results indicated that after incubation for 72 hours at the concentration of 80 microg/ml PMPs, the vessel nets in a 'spoked-wheel' pattern were shown around mixed fibrous filter membranes, number of vessel ramification was 112.5 +/- 11.31 and ratio of vessel area/CAM area was 6.19 +/- 1.29%, but there were not localized allantoic vessels developing in the control group, the number of vessel ramification and ratio of vessel area/CAM area in control group were 82.6 +/- 8.05 and 1.78 +/- 0.33 respectively, so there was significant difference between PMP and control groups. In above mentioned conditions, the number of vessel ramification and ratio of vessel area/CAM area in VEGF group were 128.4 +/- 10.02 and 7.44 +/- 1.36 respectively, so there was no difference between PMP and VEGF groups. It is concluded that PMPs show promotive effect on the formation of capillaries in chick chorioallantoic membranes.
Animals ; Blood Platelets ; physiology ; Cell-Derived Microparticles ; physiology ; Chick Embryo ; Chorioallantoic Membrane ; blood supply ; Humans ; Neovascularization, Physiologic ; drug effects ; Particle Size

This study was purposed to investigate the effects of platelet-derived membrane microparticles (PMP) on the proliferation and apoptosis of human umbilical vein endothelial cells (HUVEC). Different concentrations of thrombin were adopted to activate the platelets so as to release PMPs. Flow cytometry (FCM) was adopted to evaluate the efficiencies of different concentrations of thrombin to release PMPs. By using the HUVEC cultivated in vitro as vector, the effects of PMPs on the proliferation and apoptosis of HUVEC were investigated by MTT and FCM. The results showed that the efficiencies releasing PMPs from platelets activated by 2.0, 1.5, 1.0, 0.5 U/ml thrombin were 28.7, 47.7, 50.1 and 43.9% respectively; PMPs induced proliferation of HUVEC in a dose dependent manner. At the concentration of 40 microg/ml PMPs, the proliferation rate of HUVEC was 1.8 +/- 0.3 times as much as blank control, the proliferation rate in group of vascular endothelial growth factor was 1.9 +/- 0.5 times of as much as blank control, there was no statistic difference (p > 0.05). The PMPs inhibited HUVEC apoptosis. Compared with the apoptosis rate of control (9.4 +/- 0.5)%, apoptosis rate in PMP group (40 microg/ml) was (3.9 +/- 0.4)% (p < 0.05). The addition of VEGF (10 microl/ml) did not successfully prevented apoptosis of HUVEC with apoptosis rate of (8.0 +/- 0.8)%. It is concluded that platelets activated by 1 U/ml thrombin gets the best efficiency of PMP release, which stimulates proliferation of HUVEC and inhibits its apoptosis.
Apoptosis ; drug effects ; Blood Platelets ; physiology ; Cell Proliferation ; drug effects ; Cell-Derived Microparticles ; physiology ; Cells, Cultured ; Endothelial Cells ; cytology ; Humans ; Particle Size ; Platelet Membrane Glycoproteins ; physiology ; Thrombin ; pharmacology ; Umbilical Veins ; cytology