Inhibition of ceramide synthesis reverses endothelial dysfunction and atherosclerosis in streptozotocin-induced diabetic rats

Objectives

To explore the effect of myriocin on EDVD and atherosclerosis in diabetic rats.

Methods

Rats were fed with a high-fat/high-sucrose/high-cholesterol diet (20% sucrose, 10% animal oil, 1.0% bile salt and 2.5% cholesterol) (hereinafter defined as diabetic groups) or Purina Rodent Chow (NC group), the former was intervened with low dose streptozotocin (30 mg/kg) after feeding 1 month to make diabetic model. The NC group was intervened with citrate buffer and the diabetic rats were intervened with myriocin (0.3 mg/kg Qod) (MTD group) or just solvent (DC group) for 14 weeks. The EDVD, thickness of fatty deposition under endothelium, ceramide, PI3K/PKB/eNOS, NO and other vital parameters were measured after the rats sacrificed.

Results

In DC group, the ceramide contents in serum and aorta increased, the EDVD was impaired, the fatty deposition under endothelium increased, and the phosphorylation of PI3K/PKB/eNOS and NO release decreased all compared with the NC group (P < 0.05). Compared with the DC group, the ceramide contents in MTD group decreased, the EDVD ameliorated, the fatty deposition diminished, and PI3K/PKB/eNOS phosphorylation and NO release (P < 0.05) increased.

Conclusions

After treated with myriocin, the EDVD in diabetic rats has been improved by increasing PI3K/PKB/eNOS phosphorylation and NO release, and meanwhile the atherosclerosis has reversed.     

The effects of cadmium on VEGF-mediated angiogenesis in HUVECs

Cadmium (Cd) is a highly toxic element that causes morphologic alterations and dysfunction in blood vessels. The altered vascular function caused by cadmium has been implicated in a range of chronic diseases, including hypertension. The effects of cadmium are a multisystem phenomenon involving inflammation, hypertrophy, apoptosis, angiogenesis and important processes involved in vascular remodeling systems. Vascular endothelial growth factor (VEGF) plays a major role in cell growth and angiogenesis under pathologic conditions. VEGF secretion is related to anti-apoptosis protein expression and attenuates apoptosis in endothelial cells. This study examined the VEGF-dependent mechanisms of angiogenesis and apoptosis in cadmium-treated endothelial cells (HUVECs). The effects and mechanisms of cadmium in endothelial cells (HUVECs) were examined by exposing the cells to different doses of cadmium chloride (2.5-40 μ m). After the cadmium treatment, the angiogenesis and apoptosis mechanisms related to VEGF in cadmium-treated HUVECs were examined. As a result, the low concentration of cadmium increased the tube formation in HUVECs. In addition, cadmium at concentrations of 5 and 10 μ m increased VEGF secretion and VEGFR2 activity, which suggest that cadmium affects the growth of blood vessels. All three MAPK pathways, namely ERK, JNK and p38, were activated by cadmium in HUVECs. However, high concentrations of cadmium caused cell damage, disrupted tube formation and inhibited VEGF expression and the activities of VEGFR2 and MAPK in HUVECs. Cadmium has dual functions through VEGF-dependent mechanisms in a dose-dependent manner. In this study, the dual effects of cadmium might alter angiogenesis and induce apoptosis through VEGF pathways in HUVECs.     

Cardioprotective effects of a proanthocyanidin-rich fraction from Croton celtidifolius Baill: Focus on atherosclerosis

Proanthocyanidins are the most abundant polyphenols in human diets. Epidemiological studies have pointed to proanthocyanidins as promising molecules that could prevent the development of several coronary syndromes by inhibiting the atherogenic process. The present study was designed to investigate the antiatherogenic effects of a proanthocyanidin-rich fraction (PRF) obtained from Croton celtidifolius Baill (Euphorbiaceae) barks. In isolated human LDL, PRF caused a concentration-dependent inhibition of Cu²⁺-induced oxidative modifications, evidenced by the increasing of the lag phase of lipid peroxidation and decreasing in the oxidation rate (V_max), moreover, the protein moieties from LDL were protected against Cu²⁺-induced oxidation. In human umbilical vein endothelial cells (HUVECs), PRF reduced the ROS production stimulated by oxidized LDL. Herein, we demonstrate that oral treatment with PRF improved endothelium-dependent vasorelaxation in hypercholesterolemic LDL receptor knockout mice (LDLr^−/−), however, the fraction did not modify plasma lipids and atherosclerotic lesion size in this experimental model. Finally, our results showed for the first time that PRF prevent isolated LDL oxidation, decrease oxidative stress in endothelial cells and improve endothelial function in mice.     

Effects of netrin-1 and netrin-1 knockdown on human umbilical vein endothelial cells and angiogenesis of rat placenta

Angiogenesis is an important process essential for the development of placenta. Netrin-1 was first discovered in nervous system and was later found to play roles in angiogenesis. In order to better understand the functional relevance of netrin-1 in placental angiogenesis, we investigated the effect of netrin-1 on human umbilical vein endothelial cells (HUVECs) and rat placenta by employing up-regulation and down-regulation strategies. HUVECs and rat placenta were treated with recombinant netrin-1, and netrin-1 expression in the cells and placenta was reduced by short hairpin RNA (shRNA) in vitro and in vivo. The inhibition efficiency was determined by real-time quantitative polymerase chain reaction (RT-PCR) and Western blotting. The expression of netrin-1 was immunohistochemically located. The results demonstrated that netrin-1 promoted viability, proliferation, migration and tube formation of HUVECs. A strong reduction in cell capability was observed in vitro after netrin-1 expression was inhibited with shRNA. Netrin-1 accelerated neovascularization of placenta in pregnant rats. Suppression of netrin-1 expression in placenta resulted in reduced vascular sprouting in vivo. These findings suggest that netrin-1 is essential for the proper functioning of HUVECs and angiogenesis of rat placenta, and it is involved in the development of placenta and fetus. The proangiogenic effect of netrin-1 might offer an alternative therapeutic approach for the treatment of vascular disease of placenta.     

shRNA抑制p115表达对胃癌体外血管形成的影响

目的初步探讨胃癌BGC-823细胞高尔基体囊泡转运蛋白(golgi-vesicular transport protein,p115)对胃癌血管形成的影响及其可能机制。方法采用脂质体介导法将p115 shRNA-1318转染入胃癌BGC-823细胞株,经G418筛选出稳定转染的细胞株。利用Western blot、RT-PCR和细胞免疫荧光方法检测转染后的p115抑制效应及其对MIF、p-Akt、VEGF-A的调控情况;采用细胞活性检测实验、Transwell体外侵袭实验和血管形成实验方法分别检测转染p115 shRNA的胃癌BGC-823细胞对人脐静脉血管内皮细胞(human umbilical vein endothelial cells,HUVECs)增殖,迁移和血管形成的影响。结果 p115 shRNA-1318转染后胃癌BGC-823细胞p115、MIF、p-Akt和VEGF-A的蛋白及mRNA表达明显抑制(P<0.01);细胞免疫荧光:与对照组相比,p115 shRNA组p115、MIF及VEGF-A的色泽暗红且抑制率分别为63%、65%、68%;细胞活性检测:与对照组相比,p115 shRNA组...     

Carbon monoxide (CO)-releasing molecule-derived CO regulates tissue factor and plasminogen activator inhibitor type 1 in human endothelial cells

Introduction

Heme oxygenase-1 (HO-1) is the rate limiting enzyme that catalyzes the conversion of heme into biliverdin, free iron, and carbon monoxide (CO). The first human case of HO-1 deficiency showed abnormalities in blood coagulation and the fibrinolytic system. Thus, HO-1 or HO-1 products, such as CO, might regulate coagulation and the fibrinolytic system. This study examined whether tricarbonyldichlororuthenium (II) dimer (CORM-2), which liberates CO, modulates the expression of tissue factor (TF) and plasminogen activator inhibitor type 1 (PAI-1) in human umbilical vein endothelial cells (HUVECs), and TF expression in peripheral blood mononuclear cells (PBMCs). Additionally, we examined the mechanism by which CO exerts its effects.

Materials and Methods

HUVECs were pretreated with 50 μM CORM-2 for 3 hours, and stimulated with tumor necrosis factor-α (TNF-α, 10 ng/ml) for an additional 0-5 hours. PBMCs were pretreated with 50-100 μM CORM-2 for 1hour followed by stimulating with lipopolysaccharid (LPS, 10 ng/ml) for additional 0-9 hours. The mRNA and protein levels were determined by RT-PCR and western blotting, respectively.

Results

Pretreatment with CORM-2 significantly inhibited TNF-α-induced TF and PAI-1 up-regulation in HUVECs, and LPS-induced TF expression in PBMCs. CORM-2 inhibited TNF-α-induced activation of p38 MAPK, ERK1/2, JNK, and NF-κB signaling pathways in HUVECs.

Conclusions

CORM-2 suppresses TNF-α-induced TF and PAI-1 up-regulation, and MAPKs and NF-κB signaling pathways activation by TNF-α in HUVECs. CORM-2 suppresses LPS-induced TF up-regulation in PBMCs. Therefore, we envision that the antithrombotic activity of CORM-2 might be used as a pharmaceutical agent for the treatment of various inflammatory conditions.     

血管紧张素Ⅱ对人脐静脉内皮细胞衰老的诱导作用及对端粒酶活性的影响*

目的观察血管紧张素Ⅱ(angiotensinⅡ,AngⅡ)对人脐静脉内皮细胞(human umbilical vein endo-thelial cell,HUVECs)衰老的诱导作用及对端粒酶活性的影响。方法体外培养HUVECs,采用CCK-8法检测细胞存活率,用AngⅡ(终浓度10-6mol/L)干预,分为对照组和AngⅡ诱导组。β-半乳糖苷酶活性采用免疫化学染色方法,流式细胞术检测细胞周期来反映细胞的增殖能力;用聚合酶链反应-酶联免疫吸附法(PCR-ELISA)检测端粒酶活性。结果与对照组比较,10-6mol/L AngⅡ诱导组存活的细胞数为对照组的(77.15±6.83)%;(71.10±6.81)%的细胞呈现β-半乳糖苷酶阳性染色,流式细胞仪检测细胞周期多停滞于G0/G1期[(84.11±7.92)%],证实细胞衰老;与对照组相比,10-6mol/L AngⅡ诱导组端粒酶活性明显下降(P<0.01)。结论 AngⅡ可以诱导HUVECs衰老,其机制可能与抑制衰老细胞端粒酶活性有关。     

芹菜素对同型半胱氨酸诱导的人脐静脉内皮细胞氧化损伤的保护作用

目的:探讨芹菜素(Apigenin)对同型半胱氨酸氧化损伤的人脐静脉内皮细胞的保护作用。方法:体外培养内皮细胞,将细胞分为7组,即空白对照组(control)、溶剂对照组(DMSO)、Hcy氧化损伤组(Hcy)、氧化损伤加入槲皮素对照组(quercetin+Hcy)、氧化损伤加入芹菜素低、中、高浓度组(Apigenin-L+Hcy、Apigenin-M+Hcy、Apigenin-H+Hcy)。将5mmol/L Hcy作用于加入槲皮素及不同浓度芹菜素预培养6h的内皮细胞,继续培养24h,以细胞毒四唑盐(MTT)比色试验,乳酸脱氢酶(LDH)、谷胱甘肽过氧化酶(GSH-px)、丙二醛(MDA)、活性氧,NADPH酶活性、流式细胞凋亡率为检测指标。结果:芹菜素呈剂量依赖性降低同型半胱氨酸对内皮细胞活力的影响,降低MDA、LDH量,增加培养液中GSH-px活性,并显著减少活性氧、NADPH酶活性和细胞凋亡数量,各指标差异有显著性(P0.01)。结论:芹菜素可保护和修复同型半胱氨酸诱导的内皮细胞的损伤,其作用可能与抗氧化、抑制内皮细胞凋亡有关。     

Arginine bioavailability and endothelin-1 system in the regulation of vascular function of umbilical vein endothelial cells from intrauterine growth restricted newborns

Background and aims

Intrauterine growth restriction (IUGR) is a major risk factor for perinatal morbidity and mortality, leading to long-term adverse cardiovascular outcomes. The present study aimed to investigate the potential mechanisms in IUGR-associated vascular endothelial dysfunction.

萝卜硫素对饥饿诱导人脐静脉内皮细胞凋亡的抑制作用

目的:研究萝卜硫素抑制饥饿诱导人脐静脉内皮细胞(HUVECs)凋亡的作用。方法:以饥饿培养法诱导HUVECs凋亡。试验随机均分为正常对照(完全培养液)组、模型(模型培养液)组与萝卜硫素高、低浓度(10、5μmol/L)组。观察HUVECs形态;SRB法检测HUVECs存活率;Hoechst 33258染色法观察HUVECs的凋亡程度;吖啶橙染色和Western blot法观察HUVECs自噬水平的变化。结果:在饥饿条件下,萝卜硫素可以有效抑制饥饿HUVECs边缘发亮,脱离皿底的现象随时间延长而愈加明显;提高HUVECs的存活率;抑制HUVECs的凋亡,且具有剂量、时间依赖性;提高HUVECs的自噬水平。结论:萝卜硫素可能通过诱导自噬而起到抑制饥饿诱导HUVECs凋亡的作用。