Effect of IBD sera on expression of inducible and endothelial nitric oxide synthase in human umbilical vein endothelial cells

AIM： To study the expression of endothelial and inducible nitric oxide synthases （eNOS and iNOS） and their role in inflammatory bowel disease （IBD）. METHODS： We examined the effect of sera obtained from patients with active Crohn＇s disease （CD） and ulcerative colitis （UC） on the function and viability of human umbilical vein endothelial cells （HUVEC）. HUVECs were cultured for 0-48 h in the presence of a medium containing pooled serum of healthy controls, or serum from patients with active CD or UC. Expression of eNOS and iNOS was visualized by immunofluorescence, and quantified by the densitometry of Western blots. Proliferation activity was assessed by computerized image analyses of Ki-67 immunoreactive cells, and also tested in the presence of the NOS inhibitor, 10^-4 mol/L L-NAME. Apoptosis and necrosis was examined by the annexin-V-biotin method and by propidium iodide staining, respectively. RESULTS： In HUVEC immediately after exposure to UC, serum eNOS was markedly induced, reaching a peak at 12 h. In contrast, a decrease in eNOS was observed after incubation with CD sera and the eNOS level was minimal at 20 h compared to control （18%±16% vs 23%± 15% P〈0.01）. UC or CD serum caused a significant increase in iNOS compared to control （UC： 300%±21%; CD： 275% ± 27% vs 108% ± 14%, P〈0.01）. Apoptosis/necrosis characteristics did not differ significantly in either experiment. Increased proliferation activity was detected in the presence of CD serum or after treatment with L-NAME. Cultures showed tube-like formations after 24 h treatment with CD serum. CONCLUSION： IBD sera evoked changes in the ratio of eNOS/iNOS, whereas did not influence the viability of HUVEC. These involved down-regulation of eNOS and up-regulation of iNOS simultaneously, leading to increased proliferation activity and possibly a reduced antiinflammatory protection of endothelial cells.

Endothelial nitric oxide synthase deficiency influences normal cell cycle progression and apoptosis in trabecular meshwork cells

AIM： To clarify how the endothelial nitric oxide synthase （eNOS, NOS3） make effect on outflow facility through the trabecular meshwork （TM）. METHODS： Inhibition of NOS3 gene expression in human TM cells were conducted by three siRNAs. Then the mRNA and protein levels of NOS3 in siRNA-treated and negative control （NC） cells were determined, still were the collagen, type IV, alpha 1 （COL4A1） and fibronectin 1 by real-time PCR and Western blot analysis. In addition, NOS3 concentrations in culture supernatant fluids of TM cells were measured. Cell cycle and cell apoptosis analysis were performed using flow cytometry. RESULTS： The mRNA level of NOS3 was decreased by three different siRNA interference, similar results were obtained not only of the relative levels of NOS3 protein, but also the expression levels of COL4A1 and fibronectin 1. The number of cells in S phase was decreased, while contrary result was obtained in G2 phase. The number of apoptotic cells in siRNA-treated groups were significant increased compared to the NC samples. CONCLUSION： Abnormal NOS3 expression can make effects on the proteins levels of extracellular matrix component （e.g. fibronectin 1 and COL4A1）. Reduced NOS3 restrains the TM cell cycle progression at the G2/ M-phase transition and induced cell apoptosis.

Changes in Human Umbilical Vein Endothelial Cells Induced by Endothelial Nitric Oxide Synthase Traffic Inducer

This study investigated the changes in human umbilical vein endothelial cells （HUVECs） induced by overexpression of endothelial nitric oxide synthase traffic inducer （NOSTRIN） and its role in cellular injury. Recombinant NOSTRIN-expressing and empty vectors were transfected into cultured HUVECs, and factor Ⅷ-related antigen was examined by using immunohistochemical analysis. Growth curves were generated for both transfected and untransfected cells and these indicated that the prolifera- tive ability of cells overexpressing NOSTRIN was significantly decreased. The expression of NOSTRIN and eNOS proteins was detected by using Western blot analysis, endothelial NOS （eNOS） activity was assayed by using spectrophotometry, and NO2-/NO3- levels were measured usin~ nitrate reductase. Immunohistochemical analysis demonstrated that all groups expressed NOSTRIN in the plasma mem- brane and cytoplasm, and Western blot analysis confirmed that NOSTR1N levels were significantly higher in cells transfected with the NOSTR1N plasmid （P〈0.01）. The activity of eNOS and the levels of NO2-/NO3 were significantly decreased in NOSTRIN overexpressing cells as compared with empty vector and untransfected cells （P〈0.01 and P〈0.01, respectively）. Morphological and ultrastructural changes were observed under light and electron microscopy, and it was found that NOS- TRIN-overexpressing cells were elongated with deformities of the karyotheca, injury to the plasma membrane, increased lipids in the cytoplasm, and shortened microvilli. This study showed that overex- pression of NOSTRIN had a significant effect on eNOS activity in HUVECs and resulted in significant cellular damage.

INSULIN INDUCES NITRIC OXIDE PRODUCTION IN BOVINE AORTIC ENDOTHELIAL CELLS

Objective To examine the effects of insulin on cell proliferation, nitric oxide (NO) release and nitric oxide synthase (NOS) gene expression in bovine aortic endothelial cells ( BAEC ) . Methods The mi togenesis was assessed by MTT method; the products of NO in the culture media, by Griess reaction; and the levels of NOS mRNA in BAEC , by RT/PCR tech nique. Results BAEC were not responsive to the growth-promoting effects of insulin. Stimulation with insulin resulted a dose-dependent rise of NO in the culture supernatants 2h later, with a maximum at 12～24h and a decline at 24h. This rise was inhibited by an inhibitor of NOS (L-NAME). NOS mRNA increased slightly in BAEC without statistical significance. Conelu sion The study suggested that the insulin-induced NO release might be caused directly by NOS activation.

Shear stress effect on endothelial nitric oxide synthase in cultured human umbilical vein endothelial cells

Background: Low shear stress caused by disturbed or turbulent flow at arterial branch points is known to associate with atherosclerosis. However, shear stress at the venous valve location and its association with deep vein thrombosis are less understood due to the complex and poorly understood bi-directional flow in the valve pocket region. We investigated how venous endothelial cells respond to flow shear stress around the venous valve region using a novel in vitro system that mimics venous flow. Results: Human umbilical vein EAhy. 926 cells were cultured on a flexible silastic membrane that mimicked venous tissue. Confluent cells were exposed to sinusoidal uni-and bi-directional pulsatile shear stress (0.1 to 1 dyne/cm2) for up to 6 h. Western-blot analyses indicated that endothelial nitric oxide (eNOS) expression levels decreased regardless of all tested flow patterns, stress magnitude, and shearing time. In contrast, the expression levels of inhibitor of κB (kappa B) and α (alpha)-tubulin were unaffected by the shear stress. Conclusions: Our results indicate that shear stress causes a decrease specifically in eNOS expression, suggesting that it may play a significant role in regulating inflammation related protein expression in endothelial cells.

Simvastatin Increases the Activity of Endothelial Nitric Oxide Synthase via Enhancing Phosphorylation

3-hydroxy-3-methylgulutaryl-coenzyme A （HMG-CoA） reductase inhibitors or statins are a kind of lipid-lowering agents and have been used for the prevention and treatment of Cardiovascular diseases. Recent studies suggested that statins, besides lowering cholesterol, may protect vessels by enhancing the activity of endothelial nitric oxide synthase （eNOS）. In the present study, we investigated if simvastatin increases eNOS activity through its phosphorylation in 293 cells （293-eNOS） with stable expression of eNOS. The results showed that incubation of 293-eNOS cells with simvastatin （10 μm/L） for 2 h significantly increased in the activity of eNOS as shown by the conversion of L-arginine to L-citrulline （2889.70±201.51 versus 5630.18＋218.75 pmol/min . mg proteins） （P〈0.01）. Western blotting revealed that simvastatin increased phosphorylation of eNOS at 1177 （ser） and also 495 （thr） but did not affect the overall expression of eNOS or inducible NOS. Further study found that simvastatin raised phosphorylation levels of Akt and AMPK, and such effect could be antagonized by Akt inhibitor or AMPK inhibitor. These results suggest that simvastatin could stimulate,the activity of eNOS via its phosphorylation by Akt and AMPK, which provides a new mechanism, other than lipid-lowering effect, for the cardiovascular protection of statins.

Dexamethasone, tetrahydrobiopterin and uncoupling of endothelial nitric oxide synthase

Objective To find out whether dexamethasone induces an uncoupling of the endothelial nitric oxide synthase （eNOS）. Methods ＆ Results A major cause of eNOS uncoupling is a deficiency of its cofactor tetrahydrobiopterin （BH4）. Treatment of human EA.hy 926 endothelial cells with dexamethasone decreased mRNA and protein expression of both BH4-synthesizing enzymes： GTP cyclobydrolase I and dihydrofolate reductase. Consistently, a concentration- and time-dependent reduction of BH4, dihydrobiopterin （BH2） as well as BH4：BH2 ratio was observed in dexamethasone-treated cells. Surprisingly, no evidence for eNOS uncoupling was found. We then analyzed the expression and phosphorylation of the eNOS enzyme. Dexamethasone treatment led to a down-regulation of eNOS protein and a reduction of eNOS phosphorylation at serine 1177. A reduction of eNOS expression may lead to a relatively normal BH4： eNOS molar ratio in dexamethasone-treated cells. Because the BH4-eNOS stoichiometry rather than the absolute BH4 amount is the key determinant of eNOS functionality （i.e., coupled or uncoupled）, the down-regulation of eNOS may represent an explanation for the absence of eNOS uncoupling. Phosphorylation of eNOS at serine 1177 is needed for both the NO-producing activity of the coupled eNOS and the superoxide-producing activity of the uncoupled eNOS. Thus, a reduction of serine 1177 phosphorylation may render a potentially uncoupled eNOS hardly detectable. Conclusions Although dexamethasone reduces BH4 levels in endothelial cells, eNOS uncoupling is not evident. The reduction of NO production in dexamethasone-treated endothelial cells is mainly attributable to reduced eNOS expression and decreased eNOS phosphorylation at serine 1177.

Prednisolone inhibits SaOS2 osteosarcoma cell proliferation by activating inducible nitric oxide synthase

AIM:To investigate the effect of prednisolone,a synthetic glucocorticoid used in inflammatory diseases,on the growth of cultured osteosarcoma cells.METHODS:Two osteosarcoma cell lines with different degree of differentiation were used.SaOS2 show a rather mature phenotype,while U2 OS are negative for almost all osteoblastic markers.The cells were exposed to different concentrations of prednisolone(1-9 μmol/L) with or without antioxidants or the inhibitor of inducible nitric oxide synthase(i NOS) l-N6-(iminoethyl)-lysine-HCl(L-NIL).Cell growth was assessed by counting viable cells.The production of nitric oxide(NO) was measured in the conditioned media by the Griess method.The production of reactive oxygen species was quantified using 2'-7'-dichlorofluorescein diacetate.Western blot with specific antibodies against NOSs was performed on cell extracts.RESULTS:Prednisolone inhibited SaOS2 cell growth in a dose dependent manner.No significant effects were observed in U2OS.The inhibition of SaOS2 growth is not due to oxidative stress,because antioxidants do not rescue cell proliferation.Since high concentrations of NO inhibit bone formation,we also measured NO and found it induced in SaOS2,but not in U2 OS,exposed to prednisolone,because of the upregulation of i NOS as detected by western blot.Therefore,we treated SaOS2 with prednisolone in the presence or in the absence of L-NIL.L-NIL prevented NO release induced by prednisolone at all the concentrations apart from 9 μmol/L.At the same concentrations,we found that L-NIL rescued SaOS2 growth after exposure to prednisolone.In U2 OS cells,prednisolone did not induce NO production nor affected cell growth.All together,these data indicate that a link exists between increased amounts of NO and growth inhibition in response to prednisolone in SaOS2.CONCLUSION:Prednisolone inhibited SaOS2 proliferation by increasing the release of NO through the upregulation of i NOS,while no effect was exerted on U2OS.

Role of p38 MAPK in lipopolysaccharide-induced iNOS expression by endothelial cells

Objective:To examine the role of p38 mitogen-activated protein kinase (MAPK) in NO production and Inos expression in human endothelial cells stimulated by lipopolysaccharide (LPS). Methods: The NO level in the supernatant of the cell culture media was measured with Griess method, expressions of Inos protein and Mrna in vitro cultured endothelial cell line ECV304 were detected with immunofluorescence analysis and reverse transcriptase-PCR respectively. Immunokinase assay was employed to measure P38mapk activity. Results: Compared with the basal level of Inos expression and NO production, the NO level and the expressions of Inos Mrna and protein in the cells were increased after LPS stimulation. P38mapk activity in ECV304 cells exhibited a marked increase at 15 min after LPS stimulation, lasting for about 45 min before gradually decline. The Inos protein and Mrna expressions induced by LPS stimulation was significantly inhibited by SB203580 [4-(4-fluorophenyl)-2-(4- methylsulfinylphenyl)-5-(4-pyridyl) imidazole], a highly specific inhibitor of p38 MAPK. Conclusion: p38 MAPK plays an important role in iNOS expression and NO production in ECV304 cells, and the inhibition of the signal transduction pathway can be effective to reduce the production of iNOS and other cytokines, and therefore constitutes a useful strategy for treating septic shock or inflammation.

Relationship of endothelial nitric oxide synthase gene polymorphism with blood pressure,lipid profile and blood glucose level

To study the relationship of the polymorphism of endothelial nitric oxide synthase(eNOS)gene and blood pressure,lipid profiles and blood glucose level.By using PCR-RFLP,the eNOS Glu298Asp gene polymorphism was detected in 184 patients with essential hypertension and 196 matched healthy individuals with normal blood pressure.Taking into account eNOS Glu298Asp poly-morphisms,the relationship of blood pressure with trigly-cerides(TG),total cholesterol(TC),high density lipoprotein(HDL),low density lipoprotein(LDL)and blood glucose level was analyzed.The distribution of eNOS Glu298Asp polymorphism had no significant differ-ence between different blood pressure groups and gender groups,but there was a significant difference between dif-ferent age groups,diastolic blood pressure groups or BMI groups(P<0.05).Asp/Asp genotype significantly increased the risk of hypertension in individuals with serum TC above 5.4 mmol/L(P=0.03,OR=52.65).eNOS Glu298Asp polymorphism and serum lipid could synergis-tically modulate the blood pressure.eNOS Asp/Asp geno-type could significantly increase the risk of hypertension in individuals with serum TC over 5.4 mmol/L.eNOS Glu298Asp in combination with serum TC could be used to predict the risk of hypertension.

硝化应激在肺动脉高压中的研究进展

肺动脉高压(pulmonary hypertension,PH)是一种进行性发展的肺血管疾病,病理基础包括内皮功能障碍、平滑肌细胞异常增生、炎症浸润以及肺纤维化。PH的发生机制尚不完全清楚,但硝化应激已经证实在PH中发挥了重要作用。该文综述了活性氮(reactive nitrogen species,RNS)的种类及肺循环中RNS的来源,以及由此引发的硝化应激在PH发生发展中的作用,以期为靶向抗硝化治疗的临床应用提供参考依据。

长链非编码RNA-MEG3在人心脏微血管内皮细胞缺氧损伤中的作用

目的研究长链非编码RNA-MEG3在人心脏微血管内皮细胞(HCMEC)缺氧损伤中的作用。方法将HCMEC分为对照组、缺氧/复氧(H/R)组及缺氧/复氧联合MEG3敲减(H/R+siMEG3)组。荧光定量PCR检测MEG3及炎性因子的表达情况[白介素1β(IL-β)、IL-6、IL-8、IL-10、肿瘤坏死因子(TNF-α)];CCK-8检测HCMEC细胞的增殖活性;流式细胞术分析细胞凋亡情况;Western blotting检测PI3K/AKT/eNOS信号通路表达变化,ELISA检测一氧化氮(NO)、超氧化物歧化酶(SOD)、血管内皮生长因子(VEGF)和活性氧(ROS)表达水平。结果利用qPCR检测对照组及H/R组细胞MEG3表达,结果发现:H/R组MEG3相对表达倍数[(6.87±0.239)倍]较对照组MEG3表达倍数(1.00±0.026)倍显著升高(n=3,t=42.32,P<0.0001),提示MEG3可能在心脏微血管内皮细胞IRI中起到重要作用。H/R组细胞与对照组比较,细胞增殖活性显著减弱(P<0.01);而H/R+siMEG3组与H/R组比较,细胞增殖活性进步受到抑制(P<0.01)。H/R组较对照组PI3K、AKT及eNOS磷酸化水平显著减低,而H/R+siMEG3组细胞较H/R组磷酸化水平更低(P<0.05)。H/R组与对照组比较,NO、SOD及VEGF显著减低,而ROS水平升高(P<0.05);而H/R+siMEG3组与H/R组比较,NO、SOD及VEGF水平进步下降,ROS升高显著。利用qPCR检测各处理组细胞相关炎症基因表达,结果发现:H/R组较对照组基因表达显著升高(P<0.05);H/R+SiMEG3组较H/R组基因表达进一步升高(P<0.01)。结论长链非编码RNA-MEG3在心脏微血管内皮细胞H/R损伤过程中起到重要保护作用,靶向提升MEG3水平有望成为减缓心脏微血管IRI的潜在治疗靶点。

Decreased and dysfunctional circulating endothelial progenitor cells in patients with chronic obstructive pulmonary disease

Background It has been widely demonstrated that endothelial progenitor cells are involved in several diseases and that they have therapeutic implications. In order to define the altered pulmonary vascular homeostasis in chronic obstructive pulmonary disease, we sought to observe the level and functions of circulating endothelial progenitor calls in patients with chronic obstructive pulmonary disease. Methods The total study population included 20 patients with chronic obstructive pulmonary disease and 20 control subjects. The number of circulating endothelial progenitor cells （CD34＋/CD133＋/IVEGFR-2＋cells） was counted by flow cytometry. Circulating endothelial progenitor cells were also cultured in vitro and characterized by uptake of Dil- acLDL, combining with UEA-I, and expression of von Willebrand factor and endothelial nitric oxide synthase. Adhesion, proliferation, production of nitric oxide, and expression of endothelial nitric oxide synthase and phosphorylated-endothelial nitric oxide synthase were detected to determine functions of circulating endothelial progenitor cells in patients with chronic obstructive pulmonary disease. Results The number of circulating endothelial progenitor cells in the chronic obstructive pulmonary disease group was lower than in the control group： （0.54±0.16）% vs. （1.15±0.57）%, P 〈0.05. About 80% of adherent peripheral blood mononuclear cells cultured in vitro were double labeled with Dil-acLDL and UEA-I. The 92% and 91% of them were positive for von Willebrand factor and endothelial nitric oxide synthase, respectively. Compared with the control, there were significantly fewer adhering endothelial progenitor cells in chronic obstructive pulmonary disease patients： 18.7±4.8/field vs. 45.0±5.9/field, P 〈0.05. The proliferation assay showed that the proliferative capacity of circulating endothelial progenitor cells from chronic obstructive pulmonary disease patients was significantly impaired： 0.135±0.038 vs. 0.224±0.042, P 〈0.05. Furthermore, nitric oxide synthase （112.06±10.00 vs. 135.41±5.38, P 〈0.05）, phosphorylated endothelial nitric oxide synthase protein expression （88.89±4.98 vs. 117.98±16.49, P 〈0.05） and nitric oxide production （（25.11±5.27） Iμmol/L vs. （37.72±7.10） μmol/L, P 〈0.05） were remarkably lower in endothelial cells from the chronic obstructive pulmonary disease group than the control. Conclusion Circulating endothelial progenitor cells were decreased and functionally impaired in patients with chronic obstructive pulmonary disease.

TSB2通过减少脱偶联内皮型一氧化氮合酶氧自由基生成抑制动脉粥样硬化形成

[目的]观察TSB2抑制热休克蛋白90(HSP90)与内皮型一氧化氮合酶(eNOS)的结合对动脉粥样硬化形成的影响。[方法]用TSB2处理人脐静脉内皮细胞,用免疫共沉淀法检测HSP90与eNOS的结合情况。利用C57BL/6小鼠和低密度脂蛋白受体敲除(LDLR^(-/-))小鼠,普通饮食(ND)或高脂饮食(HFD)喂养12周,同时腹腔注射PBS或TSB2,分为4组:C57BL/6+ND+PBS组、LDLR^(-/-)+ND+PBS组、LDLR^(-/-)+HFD+PBS组、LDLR^(-/-)+HFD+TSB2组。提取主动脉检测HSP90与eNOS的结合情况,检测主动脉和主动脉窦的粥样硬化斑块情况、一氧化氮(NO)和氧自由基(O_(2)^(·-))生成情况,同时使用左旋精氨酸的竞争性底物L-单甲基-精氨酸(L-NMMA)明确NO的生成和一氧化氮合酶抑制剂左旋硝基精氨酸甲酯(L-NAME)明确O_(2)^(·-)的生成。[结果]与对照组相比,加入TSB2处理的人脐静脉内皮细胞后,HSP90与eNOS的结合水平减少41.06%(P<0.05)。与LDLR^(-/-)+HFD+PBS组相比,LDLR^(-/-)+HFD+TSB2组小鼠主动脉中HSP90与eNOS的结合水平减少40.95%(P<0.05),主动脉内皮细胞O_(2)^(·-)生成水平减少63.73%(P<0.05)(L-NAME明显抑制LDLR^(-/-)+HFD+PBS组O_(2)^(·-)的生成),但NO生成量未见明显变化(L-NMMA抑制所有组NO的生成),同时主动脉及主动脉窦的斑块形成水平分别减少59.39%和68.86%(P<0.05)。[结论]TSB2通过抑制主动脉血管内皮细胞HSP90与eNOS的结合,减少血管内皮细胞脱偶联eNOS的O_(2)^(·-)生成,最终抑制动脉粥样硬化形成。

神经营养素-3过表达诱导多能干细胞治疗糖尿病性勃起功能障碍大鼠的实验研究

目的 探讨神经营养素-3过表达诱导多能干细胞(iPSC-NT-3)对糖尿病性勃起功能障碍(DIED)大鼠的治疗作用。方法 腹腔注射链脲佐菌素建立糖尿病模型大鼠,皮下注射阿扑吗啡对DIED模型进行验证。选择24只造模成功的DIED大鼠,随机分为模型对照组、诱导多能干细胞(iPSC)治疗组和iPSC-NT-3治疗组;腹腔注射柠檬酸钠-柠檬酸缓冲液的8只SD大鼠作为正常对照组。各组大鼠腹腔注射戊巴比妥钠进行麻醉,iPSC治疗组和iPSC-NT-3治疗组分别将iPSC和iPSC-NT-3用微量注射针注射入大鼠阴茎海绵体内,正常对照组和模型对照组同法注射同体积的磷酸缓冲液。治疗后第4周,观察各组大鼠的一般情况,评估性功能和阴茎勃起功能。采用定量聚合酶链反应(q-PCR)和Western blot实验检测神经营养素-3(NT-3)、CD31、血管内皮生长因子(VEGF)、内皮型一氧化氮合酶(eNOS)、结蛋白(Desmin)、α-平滑肌肌动蛋白(α-SMA)的mRNA和蛋白的表达。结果 治疗前和治疗后4周,模型对照组、iPSC治疗组和iPSC-NT-3治疗组大鼠体质量和血糖水平的组内、组间差异均无统计学意义(P>0.05)。在大鼠首次爬背时间比较中,模型对照组较正常对照组延长,iPSC治疗组、iPSC-NT-3治疗组较模型对照组缩短,iPSC-NT-3治疗组较iPSC治疗组缩短,差异均有统计学意义(P<0.05);在舔嗅次数、骑跨次数和插入次数的比较中,模型对照组均较正常对照组减少,iPSC治疗组、iPSC-NT-3治疗组较模型对照组增加,iPSC-NT-3治疗组较iPSC治疗组增加,差异均有统计学意义(P<0.05)。在ICP和ICP/MAP的比较中,模型对照组较正常对照组降低,iPSC治疗组、iPSC-NT-3治疗组较模型对照组升高,iPSC-NT-3治疗组较iPSC治疗组升高,差异均有统计学意义(P<0.05)。在大鼠阴茎海绵体NT-3、CD31、VEGF、eNOS、Desmin和α-SMA的mRNA表达水平比较中,模型对照组较正常对照组降低,iPSC治疗组、iPSC-NT-3治疗组较模型对照组升高,iPSC-NT-3治疗组较iPSC治疗组升高,差异均有统计学意义(P<0.05)。在大鼠阴茎海绵体NT-3、CD31、VEGF、eNOS、Desmin、α-SMA蛋白水平比较中,模型对照组较正常对照组降低,iPSC治疗组、iPSC-NT-3治疗组较模型对照组升高,iPSC-NT-3治疗组较iPSC治疗组升高,差异有统计学意义(P<0.05)。结论 iPSC-NT-3可通过促进海绵体组织eNOS、血管内皮及平滑肌的生成而改善DIED大鼠的性功能和勃起功能,是一种潜在的治疗DIED的方法。

氧化苦参碱通过Akt-eNOS-NO信号通路改善棕榈酸诱导的血管内皮细胞损伤

目的探讨氧化苦参碱(oxymatrine,OMT)对棕榈酸(palmitic acid,PA)致血管内皮细胞损伤的改善作用及其机制。方法MTT法检测人脐静脉血管内皮细胞(human umbilical vein endothelial cells,HUVECs)存活率;流式细胞仪检测细胞凋亡;ELISA法检测细胞内活性氧(ROS)水平以及细胞培养液中乳酸脱氢酶(LDH)、丙二醛(MDA)、超氧化物歧化酶(SOD)、谷胱甘肽过氧化物酶(GSH-PX)及一氧化氮(NO)水平;Western blot法检测bcl-2、bax、caspase-3、Akt和内皮型一氧化氮合酶(endothelial nitric oxide synthase,eNOS)的蛋白表达。结果OMT对PA诱导的HUVECs细胞存活率下降和LDH水平升高有明显的抑制作用;降低细胞凋亡;上调bcl-2/bax蛋白比值及下调caspase-3蛋白表达;在细胞培养液中降低ROS和MDA水平而提高SOD、GSH-PX和NO水平;上调Akt和eNOS的磷酸化蛋白表达。结论OMT通过Akt-eNOS-NO信号通路改善PA诱导的血管内皮细胞损伤。

切应力通过Pim1/Akt调节人脐静脉内皮细胞内皮型一氧化氮合酶Ser633和Ser1177位点磷酸化

目的探讨不同模式的血流切应力对人脐静脉内皮细胞(HUVECs)Pim1表达的影响,以及对内皮型一氧化氮合酶(eNOS)Ser1177和Ser633位点磷酸化的调控作用。方法体外原代培养的HUVECs,采用平行平板流动腔系统给HUVECs分别施加15 dyn/cm2层流切应力(LSS)和(0.5±4)dyn/cm2振荡切应力(OSS),Western blotting法检测Pim1、Akt和Akt Ser473磷酸化、eNOS、eNOS Ser1177和Ser633位点磷酸化蛋白表达。用特异性小干扰RNA(siRNA)技术分别敲低HUVECs中Pim1和Akt进行干预。结果与OSS刺激相比较,LSS显著上调HUVECs中Pim1蛋白表达水平(P<0.01),同时,Akt Ser473磷酸化、eNOS Ser633和Ser1177位点磷酸化蛋白表达增加(P<0.05或P<0.01);siPim1和Pim1特异性抑制剂SMI-4a干预后,LSS诱导的Pim1蛋白表达显著被抑制(P<0.05),同时Akt Ser473磷酸化、eNOS Ser633和Ser1177位点磷酸化蛋白表达均降低(P<0.05或P<0.01)。敲低Akt,LSS诱导的Akt Ser473磷酸化蛋白表达显著被抑制(P<0.05),同时也显著抑制LSS上调的eNOS Ser633和Ser1177磷酸化蛋白表达(P<0.05),而对LSS上调的Pim1表达无影响(P>0.05)。结论切应力可以通过Pim1/Akt信号通路调节HUVECs eNOS Ser633和Ser1177位点磷酸化。

棕榈酸激活PP4和PP2A诱导HUVECs内皮功能障碍的作用机制

目的探讨蛋白磷酸酶4(PP4)和蛋白磷酸酶2A(PP2A)在棕榈酸(PA)诱导的内皮功能障碍中的作用及机制。方法采用PA处理人脐静脉内皮细胞(HUVECs)体外建立脂毒性细胞模型,用PP2A亚家族抑制剂福司曲星(FST)或冈田酸(OA)预处理和特异性小干扰RNA(siRNA)技术沉默PP2Ac和PP4c基因,用慢病毒感染过表达PP4R2基因转染HUVECs;蛋白免疫印迹分析(Western blot)检测eNOS总蛋白、eNOS Ser633和eNOS Ser1177磷酸化水平及PP4各亚基、PP2Ac亚基蛋白表达水平,DAF-FM DA荧光探针检测细胞内一氧化氮(NO)含量,划痕实验以及小管形成实验检测内皮细胞迁移能力(迁移率)和小管形成能力(管长度),免疫共沉淀(Co-IP)法观察HUVECs内eNOS、PP4c、PP4调节亚基PP4R2及PP4R3α之间的相互作用。结果与Control组相比,PA组eNOS Ser633和eNOS Ser1177磷酸化水平呈时间和浓度依赖性增加(P<0.05),但eNOS总蛋白表达水平变化不明显(P>0.05);与PA组相比,FST+PA组、OA+PA组eNOS Ser633和Ser1177的磷酸化水平增加(P<0.05),细胞内NO含量增加(P<0.05);与si-Control+PA组相比,si-PP2Ac+PA组eNOS Ser1177的磷酸化水平增加(P<0.05),si-PP4c+PA组eNOS Ser633磷酸化水平增加(P<0.05);与Control相比,PA组抑制PP4R2蛋白表达(P<0.05);与Vector+PA组相比,OE-PP4R2+PA组eNOS Ser633磷酸化水平增加(P<0.05),但eNOS Ser1177磷酸化水平无明显变化(P>0.05),同时细胞内NO产量增加,内皮细胞的迁移能力以及小管形成能力增强(P<0.05);Co-IP检测显示,eNOS蛋白与PP4c蛋白、PP4R2蛋白、PP4R3α蛋白存在共定位关系。结论PA激活PP2A和PP4分别诱导eNOS在Ser1177和Ser633去磷酸化,降低eNOS活性,导致内皮功能障碍,且PP4可能以三聚体形式(PP4R2-PP4c-PP4R3α)存在,提示在血浆游离脂肪酸增多时,调节PP4R2或PP4R3α活性可减轻细胞脂毒性,保护血管内皮细胞,改善内皮功能障碍。