17β-雌二醇对牛视网膜毛细血管内皮细胞eNOS mRNA及NO调控的实验研究

目的探讨17β-雌二醇(E2)在不同氧(O2)环境下对牛视网膜毛细血管内皮细胞(BRECs)一氧化氮合酶(eNOS)mRNA及NO的影响。方法在正常O2及缺O2环境下,采用不同生理浓度(10-12、10-10、10-8mol/L)的17β-E2及雌激素受体拮抗剂他莫昔芬处理培养的BRECs。采用RT-PCR检测eNOS mRNA,硝酸还原酶法测定NO。结果①低O2条件下BRECs的eNOS mRNA、NO表达较正常O2条件下明显增多(P<0.05)。②正常O2及低O2条件下,不同生理浓度17β-E2作用24 h后,17β-E2均呈浓度依赖性促进BRECs的eNOS mRNA、NO表达(P<0.05);10-8mol/L 17β-E2作用8、24 h,eNOS mRNA表达量呈时间依赖性增多(P<0.05)。结论生理浓度的17β-E2使BRECs的eNOS mRNA、NO表达呈浓度、时间依赖性增加。     

苯扎贝特对牛主动脉内皮细胞一氧化氮合酶基因表达的影响及其机制的研究

目的研究过氧化物酶体增生物激活受体α(peroxisomeproliferator-activatedreceptoralpha,PPARα)的配体苯扎贝特对原代牛主动脉内皮细胞(bovineaortaendothelialcells,BAEC)一氧化氮合酶(endothelialnitricoxidesynthase,eNOS)基因表达的影响并探讨其机制。方法分离和培养牛主动脉内皮细胞,采用Northern印迹法、Western印迹法检测苯扎贝特对BAECeNOSmRNA和蛋白质表达的影响,采用定量PCR的方法及NO试剂盒检测苯扎贝特对eNOSmRNA半衰期及NO产生的影响;继而采用Western印迹法,给予不同的信号转导通路抑制剂研究苯扎贝特影响eNOS表达所通过的信号转导途径,此外,构建了由人eNOS启动子驱动的荧光报告基因,研究苯扎贝特对eNOS启动子活性的影响。结果苯扎贝特以浓度(50~200μmol/L)依赖的方式明显上调BAEC细胞eNOS的mRNA和蛋白质表达(P<0.05),并促进一氧化氮(nitricoxide,NO)的生成[对照组(14.97±1.29)μmol/L,苯扎贝特不同浓度组(25.12±1.25)μmol/L,(30.12±1.85)μmol/L,(33.47±1.22)μmol/L],增强eNOS-ser-1179位点的磷酸化表达(P<0.05),但是对eNOS-thr-497位点的磷酸化表达几乎没有抑制作用,定量PCR证实苯扎贝特增加eNOSmRNA的半衰期(从3.1~6.1h),进一步的研究显示苯扎贝特以浓度依赖的方式增加人eNOS启动子驱动的荧光报告基因的荧光活性(相对的荧光活性在100μmol/L和200μmol/L组分别为4429.43±391.41,6187.5±307.53,对照组为3361.81±316.85),增加磷酸化丝裂原激活的蛋白激酶(mitogen-activatedproteinkinase,MAPK)的蛋白质表达(P<0.05及P<0.01),而PPARα、磷脂酰肌醇3-激酶(phosphatidylinositol3-kinase,PI3K)和MAPK抑制剂可明显逆转苯扎贝特对eNOS表达的上调作用(P<0.01)。结论苯扎贝特通过上调eNOS的蛋白质表达、促进eNOS的磷酸化、增强eNOS的转录及eNOSmRNA的稳定性,从而促进NO的生成,其效应的发挥既通过依赖于PPARα的方式,也可以经MAPK和PI3K信号通路介导的不依赖于PPARα的“非基因效应”,揭示了PPARα的配基苯扎贝特的降脂外作用包括抗动脉粥样硬化和抗高血压的可能作用机制。     

二陈汤合桃红四物汤含药血清对ox-LDL诱导内皮细胞损伤的保护作用及机制

目的观察二陈汤合桃红四物汤含药血清对氧化型低密度脂蛋白(ox-LDL)诱导内皮细胞损伤的保护作用并探讨其可能的机制。方法培养EA.hy926细胞,随机分为对照组、ox-LDL组、干预组、抑制剂组。流式细胞仪检测各组细胞凋亡水平,比色法检测细胞内丙二醛(MDA)、一氧化氮(NO)水平及超氧化物歧化酶(SOD)活性,ELISA检测细胞上清液中肿瘤坏死因子α(TNF-α)、白细胞介素6(IL-6)水平,Western blot检测磷脂酰肌醇3-激酶(PI3K)、磷酸化AKT(p-AKT)、内皮型一氧化氮合酶(eNOS)蛋白表达水平。结果与对照组比较,ox-LDL组细胞上清液中TNF-α和IL-6水平显著升高(P0.01),细胞内MDA含量显著升高(P0.01),SOD活性明显降低(P0.05),上清液中NO水平显著降低(P0.01),活性氧(ROS)含量和细胞凋亡率明显升高,PI3K、eNOS蛋白表达水平和AKT蛋白磷酸化水平显著降低(P0.01)。与ox-LDL组比较,干预组细胞上清液中TNF-α和IL-6水平显著降低(P0.01),细胞内MDA含量显著降低(P0.01),SOD活性明显升高(P0.05),上清液中NO水平显著升高(P0.01),ROS含量和细胞凋亡率明显降低,PI3K、eNOS蛋白表达水平和AKT蛋白磷酸化水平显著升高(P 0.01)。与干预组比较,抑制剂组细胞上清液中TNF-α和IL-6水平显著升高(P0.01),细胞内MDA含量显著升高(P0.01)、SOD活性明显降低(P0.05),上清液中NO水平明显降低(P0.05),细胞内ROS含量升高,PI3K、eNOS蛋白表达水平和AKT蛋白磷酸化水平显著降低(P0.01)。结论二陈汤合桃红四物汤含药血清能有效保护ox-LDL诱导的内皮细胞损伤,其机制可能与激活PI3K/AKT/eNOS信号通路有关。     

天麻酚类成分对脑缺血模型大鼠海马一氧化氮和一氧化氮合酶的影响

目的探讨天麻酚类成分对脑缺血大鼠海马NO和一氧化氮合酶(NOS)的影响。方法采用双侧颈总动脉永久性结扎法,造成大鼠脑缺血模型。造模6周后,SD大鼠40只随机分为5组,假手术组、模型组、尼莫地平组、天麻酚类成分高剂量组(高剂量组)和天麻酚类成分低剂量组(低剂量组),每组8只。给药3周后,比色法检测海马NO含量和NOS活性,免疫印记法检测大鼠海马NOS 3种亚型(nNOS,iNOS,eNOS)的表达。结果与假手术组比较,模型组大鼠海马NO含量、NOS活性及nNOS和iNOS表达明显升高,eNOS表达明显降低;与模型组比较,尼莫地平组和高剂量组大鼠海马NO含量、NOS活性及nNOS和iNOS表达明显降低,eNOS表达明显升高;低剂量组大鼠NOS活性和iNOS表达明显降低,差异有统计学意义(P<0.05,P<0.01)。结论天麻酚类成分对脑缺血大鼠海马NO损伤有保护作用。     

氟伐他汀对人脐静脉内皮细胞游离钙离子水平及内皮型一氧化氮合酶活性的影响

目的:观察氟伐他汀对人脐静脉内皮细胞(HUVECs)游离钙离子水平及内皮型一氧化氮合酶(eNOS)活性的影响及可能机制。方法:体外培养HUVECs,随机分为5组:空白对照组,氟伐他汀(10-8,10-7,10-6,10-5mol/L)组。采用硝酸还原酶法测定细胞上清液中NO含量,液体闪烁计数仪测定L-[3H]-精氨酸和L-[3H]-瓜氨酸的含量,用激光共聚焦扫描显像系统检测内皮细胞内游离钙离子浓度([Ca2 ]i)水平的变化。结果:与空白对照组比较,10-8,10-7,10-6,10-5mol/L氟伐他汀孵育细胞12h后可显著升高HUVECs细胞内eNOS活性,促进NO释放,同时伴有[Ca2 ]i升高,且呈浓度依赖性。另外,10-5mol/L氟伐他汀在0～12h时间段呈时间依赖性增高eNOS活性,作用12h使eNOS活性达到最高(P<0.01)。结论:氟伐他汀呈浓度依赖性升高HUVECseNOS活性和促进NO释放,该作用与其增加内皮细胞内[Ca2 ]i有关。     

沙格列汀对过氧化氢诱导损伤的血管内皮细胞二甲基精氨酸二甲胺水解酶/非对称性二甲基精氨酸/内源性一氧化氮合酶通路影响的研究

目的观察二肽基肽酶-4(DPP-4)抑制剂沙格列汀对过氧化氢(H2O2)诱导损伤的血管内皮细胞二甲基精氨酸二甲胺水解酶/非对称性二甲基精氨酸/内源性一氧化氮合酶(DDAH/ADMA/eNOS)通路的影响。方法以培养人脐静脉内皮细胞株(HUVEC)作为靶细胞,在内皮细胞培养基中加入100μmol/L的H2O2制备细胞损伤模型,以20μmol/L沙格列汀进行干预,观察24~72h,检测细胞上清一氧化氮(NO)含量、ADMA浓度,检测细胞中NOS活性、DDAH活性及DDAH蛋白表达量。结果H2O2作用HUVEC后,细胞上清中NO含量降低,而ADMA浓度增加(P0.05)。细胞中NOS活性、DDAH活性、DDAH-Ⅱ蛋白表达量降低(P0.05);而加入沙格列汀,细胞上清中NO含量升高,ADMA浓度降低(P0.05)。细胞中NOS活性、DDAH活性、DDAH-Ⅱ蛋白表达量升高(P0.05)。结论沙格列汀通过对DDAH/ADMA/eNOS通路的调节作用改善H2O2诱导的内皮细胞NO生成减少。     

丹参酮ⅡA对血管紧张素Ⅱ所致主动脉内皮细胞游离钙离子及产生一氧化氮的影响

目的 通过观察猪主动脉内皮细胞在血管紧张素Ⅱ(AngⅡ)作用下时,不同浓度和不同作用时间的丹参酮ⅡA(TSN)对血管内皮细胞分泌一氧化氮(NO)及其内皮型一氧化氮合酶(eNOS)基因表达的影响、细胞内游离钙离子浓度的变化,探讨TSN对血管内皮细胞的保护作用.方法 采用硝酸还原法、免疫组织化学法,首先分别检测不同浓度(10-8～10-6 mol/L)和不同作用时间(1、6、24 h)的AngⅡ对培养的猪主动脉内皮细胞产生NO及其eNOS蛋白质表达的影响;然后比较在10-6mol/L的AngⅡ作用的不同点(0 h点为A组、6 h点为B组)加入不同浓度(10、50 mg/L)TSN,分别检测作用1、6、24 h后内皮细胞的NO生成和eNOS的蛋白质表达变化.用激光共聚焦扫描显像系统检测内皮细胞内游离钙离子浓度([Ca2+]i)水平的变化.结果 (1)随着AngⅡ浓度的增加、作用时间的延长,内皮细胞NO的产生及eNOS的表达呈顺序下降(P＜0.01),表现出剂量、时间依赖性的负性作用.(2)TSN可抑制AngⅡ对内皮细胞分泌NO及eNOS表达的负性作用(P＜0.01),但尚不能恢复到空白对照组水平(P＜0.05);此作用与TSN的浓度无明显关系(P＞0.05).在TSN作用1、6 h,A组的抑制效应明显强于B组(P＜0.05);随着作用时间延长至24 h,两组间差异无显著性(P＞0.05).(3)AngⅡ可引起主动脉内皮细胞[Ca2+]i显著升高(P＜0.01),TSN可部分抑制AngⅡ诱导的内皮细胞[Ca2+]i升高(P＜0.05).结论 TSN可抑制AngⅡ对血管内皮细胞分泌NO以及细胞eNOS蛋白质表达的负性作用,可能通过多种途径对血管内皮细胞及其功能起到保护作用.     

小葱葱白提取物对人脐静脉内皮细胞一氧化氮及一氧化氮合酶的影响

目的观察小葱葱白提取物对人脐静脉内皮细胞(HUVECs)分泌一氧化氮(NO)和内皮型一氧化氮合酶(eNOS)的影响,探讨其对HUVECs血管活性分子分泌的调节作用。方法从小葱葱白中提取活性成分,体外培养HUVECs用不同浓度(100g/L,50g/L,25g/L,12.5g/L)的葱白提取物分别作用于HUVECs。观察细胞形态,MTT法观察葱白提取物对HUVECs活性的影响,比色法测定各组的NO含量,RT-PCR法及Western Blot法测定内皮型eNOS的表达水平。结果和对照组比较,小葱葱白提取物对内皮细胞形态和活性无明显影响,能增加HUVECs释放NO及eNOS生成(P<0.05或P<0.01)。结论小葱葱白提取物可能通过增加eNOS生成而提高HUVECs释放NO,从而保护内皮功能。     

肿瘤坏死因子-α对内皮祖细胞功能及其一氧化氮合酶含量的影响

目的观察肿瘤坏死因子-α(TNF-α)对外周血内皮祖细胞(EPC)功能及一氧化氮合酶含量的影响。方法采用密度梯度离心法从外周血获得单个核细胞,将其接种在人纤维连接蛋白包被的培养板上,培养7d后收集贴壁细胞,加入不同浓度TNF-α(分别为0,10,20,50和100mg/L)分别培养0,6,12,24和48h。激光共聚焦显微镜鉴定异硫氰酸荧光黄标记荆豆凝集素Ⅰ和Dil标记的乙酰化低密度脂蛋白双染色阳性的细胞为正在分化的EPC;将其在倒置荧光显微镜下计数,然后分别采用MTT比色法、改良的Boyden小室、黏附能力测定实验和体外血管生成试剂盒来观察EPC的增殖、迁移、黏附和体外血管形成能力。免疫印迹杂交法(Westernblot)半定量测定诱导型和内皮型一氧化氮合酶(iNOS和eNOS)含量。结果TNF-α降低外周血EPC增殖、迁移、黏附、体外血管形成能力、iNOS和eNOS含量,并且EPC增殖、迁移、黏附、体外血管形成能力、iNOS和eNOS含量随TNF-α浓度与作用时间增加而降低。结论TNF-α降低EPC的增殖、迁移、黏附和体外血管形成能力,还减少EPC中iNOS和eNOS含量。     

比索洛尔对一氧化氮和内皮型一氧化氮合酶昼夜节律的影响

目的探讨比索洛尔对大鼠一氧化氮和内皮型一氧化氮合酶(eNOS)及心肌组织eNOSmRNA表达水平昼夜节律的影响。方法健康雄性SD大鼠128只,体质量250～300g,随机分为4组:7:00灌药组(早灌药组)、19:00灌药组(晚灌药组)、7:00对照组(早对照组)、19:00对照组(晚对照组),每组32只。每日早灌药组与晚灌药组均给予比索洛尔3mg/kg灌服,两对照组分别于7:00与19:00给予相同剂量的安慰剂灌服。4周后,分别于同日内不同时间点(2:00,8:00,14:00,20:00)处死4大组大鼠中各8只大鼠,留取血清和心肌组织。分别采用比色法和硝酸还原法、逆转录多聚酶链反应法检测血和心肌组织中eNOS、一氧化氮的含量或活性以及eNOSmRNA的表达水平。结果两灌药组之间、两对照组之间血清及组织一氧化氮、eNOS含量或表达差异无统计学意义(均P>0.05),但灌药组和对照组之间血清及组织一氧化氮、eNOS含量或表达差异有统计学意义(均P<0.05),灌药组的一氧化氮、eNOS含量明显升高,eNOSmRNA的表达增强(P<0.05)。各组血清及组织一氧化氮、eNOS含量或表达均存在昼夜节律,灌药组部分节律振幅、峰值改变。灌药组和对照组各组的组织eNOSmRNA存在典型昼夜节律,节律振幅无差异。早、晚灌服比索洛尔对于一氧化氮、eNOS以及eNOSmRNA昼夜节律的影响有所不同。结论比索洛尔升高血清及组织一氧化氮、eNOS的含量,促进组织eNOSmRNA的表达。比索洛尔可对内皮源性血管活性物质的时间生物学特征产生影响,用药时间不同,对各参数的影响亦有所不同。     

Sesamin induces nitric oxide and decreases endothelin-1 production in HUVECs: possible implications for its antihypertensive effect

OBJECTIVE: Sesamin has been proved to be antihypertensive. Nitric oxide (NO) is the most important vascular relaxing factor that is regulated in endothelium. Endothelin-1 (ET-1) is characterized as a potent vasoconstrictor and is also regulated in endothelium. Alterations in the endothelial production of NO and ET-1 are known to correlate with hypertension. This study investigated the effect of sesamin on NO and ET-1 in the human umbilical vein endothelial cells (HUVECs). DESIGN: The concentrations of NO and ET-1 in the medium of HUVECs treated by sesamin were measured. The mRNA and protein expressions of nitric oxide synthase (NOS), endothelin converting enzyme-1 (ECE-1), and endothelin-1 (ET-1) were also investigated. Other than the mRNA and protein expression, NOS activity and cyclic GMP (cGMP) were detected. METHODS: The NO concentration was detected by colorimetric assay. The cGMP and ET-1 were analyzed by EIA. The eNOS, ECE-1, and ET-1 mRNA expressions were assayed by Northern blot. The eNOS and ECE-1 protein expressions were analyzed by Western blot. The NOS activity was assayed by detecting the level of [H]-1-citrullin transformed from [H]-1-arginine. RESULTS: Sesamin not only increased the NO concentration in the medium of HUVECs in a dose-dependent manner after 24 h, but also induced eNOS mRNA and protein expressions. NOS activity in the HUVECs was also induced by sesamin. The content of cGMP was induced by sesamin through NO signaling. On the other hand, the ET-1 concentration in the medium of HUVECs treated by sesamin was suppressed in a dose-dependent manner after 24 h. The ECE-1 protein and mRNA expressions were also inhibited by sesamin. However, the mRNA expression of prepro ET-1 was not influenced by sesamin. CONCLUSION: From the above results, it is suggested that sesamin may improve hypertension by its ability to induce NO and inhibit ET-1 production from endothelial cells. The increase of NO by sesamin is through the induction of eNOS gene expression. The decrease of ET-1 by sesamin is through the inhibition of ECE gene expression, but is not through the inhibition of prepro ET-1 gene expression.     

糖基化终产物对人脐静脉内皮细胞一氧化氮合酶活性和表达的影响及二甲双胍的保护作用

目的 探讨糖基化终产物及二甲双胍对人脐静脉内皮细胞一氧化氮合酶活性和表达的影响.方法 用胶原酶法分离人脐静脉内皮细胞并加以培养.将内皮细胞与不同浓度的糖基化终产物和二甲双胍分别孵育3、6、12、24 h,CCK-8法测定人脐静脉内皮细胞增殖活性.硝酸还原酶法测定一氧化氮含量,分光光度法测定一氧化氮合酶活性,蛋白免疫印迹法检测内皮型一氧化氮合酶蛋白表达水平.结果 糖基化终产物抑制人脐静脉内皮细胞增殖,二甲双胍促进人脐静脉内皮细胞增殖.糖基化终产物抑制人脐静脉内皮细胞的一氧化氮生成和一氧化氮合酶活性(P<0.01),呈剂量、时间依赖关系.二甲双胍(与对照组相比)或与糖基化终产物共同干预(与糖基化终产物组相比)均增加人脐静脉内皮细胞一氧化氮生成和一氧化氮合酶活性(P<0.01).糖基化终产物与人脐静脉内皮细胞共同孵育24 h后,内皮型一氧化氮合酶表达水平明显下降;二甲双胍上调内皮型一氧化氮合酶的表达;与糖基化终产物组相比,糖基化终产物与二甲双胍共同干预组内皮型一氧化氮合酶表达上调(P<0.01).结论 二甲双胍能够改善糖基化终产物导致的人脐静脉内皮细胞损伤.     

葛根素对心肌细胞一氧化氮影响的研究

目的 研究葛根素对心肌细胞H9C2一氧化氮的影响.方法 eNOS蛋白用Western blot方法检测,eNOS基因用RT-PCR方法检测,并测定一氧化氮含量.结果 在葛根素2 mg/ml浓度下作用24 h,可明显提高心肌细胞H9C2 eNOS蛋白和基因表达.结论 葛根素在心血管方面的保护作用很可能与调节一氧化氮含量及其合酶表达有关.     

TNF-α对血栓调节蛋白表达活性的影响及其作用机制的探讨

目的 观察肿瘤坏死因子(TNF)-α对血栓调节蛋白(TM)在原代人脐静脉内皮细胞(HUVECs)的表达和活性的影响,并初步探讨其作用机制。方法 体外培养HUVECs,实验分为3组:1对照组:加入与TNF-α等体积的PBS培养细胞6 h;2 TNF-α组:TNF-α终浓度为10 ng/ml孵育细胞6 h;3 BAY11-7082抑制组:BAY11-7082终浓度2μg/ml孵育细胞1 h阻断NF-κB通路后再用10 ng/ml的TNF-α干预细胞6 h。分别采用流式细胞技术、荧光定量聚合酶链反应(RT-PCR)和酶标仪检测TM蛋白、mRNA表达及活性强度。结果 TNF-α组相比与对照组和BAY11-7082抑制组在TM的蛋白、mRNA水平上均明显降低(P<0.05),TM活性也明显减弱(P<0.05)。而BAY11-7082抑制组相比与对照组在TM蛋白水平和活性均无差异,在mRNA水平上升高(P<0.05)。结论 TNF-α可明显降低TM表达,并抑制其活性,NF-κB通路参与了这一过程。     

Co-expression and modulation of neuronal and endothelial nitric oxide synthase in human endothelial cells

Despite originally identified in neurones, the neuronal type of nitric oxide synthase (nNOS) is present also in cardiac and skeletal myocytes. Whether nNOS is functionally expressed in human endothelial cells--as the endothelial enzyme (eNOS)--is unknown. Human umbilical vein endothelial cells (HUVEC) were studied under control culture conditions and after 48 h treatment with cytomix (human tumour necrosis factor-alpha, interferon-gamma and E. coli endotoxin). We tested: (i) localisation and expression of nNOS and eNOS proteins by immunostaining and immunoblotting; (ii) activity of nNOS and eNOS by measuring L-arginine to L-citrulline conversion with 1-(2-trifluoromethylphenyl)imidazole (TRIM), a specific nNOS antagonist, in sub-cellular fractions; (iii) intracellular cGMP levels, as a marker for nitric oxide production, after TRIM pre-treatment, by radioimmunoassay. nNOS protein was expressed in the cytosolic fraction and immunolocalised in cultured HUVEC, and co-localised with the eNOS protein in frozen sections of the human umbilical cord. nNOS protein contributed to total L-citrulline production as TRIM selectively and dose-dependently reduced L-citrulline synthesis in the cytosolic but not particulate fraction of HUVEC. Similarly, TRIM reduced intracellular cGMP content both at baseline and after stimulation with a calcium ionophore. Cytomix down-regulated the expression and function of both nNOS and eNOS while no inducible NOS (iNOS) was detected. In conclusion, a functional neuronal type of NOS is co-expressed with the endothelial NOS type in HUVEC, suggesting a possible role for nNOS in regulation of blood flow.     

一氧化氮/环鸟苷酸信号传导通路对高葡萄糖环境中人脐静脉内皮细胞内皮抑素表达的影响

目的 研究一氧化氮/环鸟苷酸信号传导通路对高葡萄糖时人脐静脉内皮细胞表达内皮抑素的调控.方法 采用5.6、11.2、22.4 mmol/L葡萄糖培养人脐静脉内皮细胞72 h,硝酸还原酶法测定培养上清液中一氧化氮含量,Western blot法检测内皮抑素蛋白表达水平.在11.2 mmol/L葡萄糖作用72 h(对照组)...     

Glucagon-like Peptide-1 Receptor Agonist Liraglutide Inhibits Endothelin-1 in Endothelial Cell by Repressing Nuclear Factor-Kappa B Activation

Purpose

The increase in endothelin-1 (ET-1) and the decrease in endothelial nitric oxide synthase (eNOS) both induce vasoconstriction and lead to molecular changes associated with diabetes mellitus and atherosclerosis. Glucagon-like peptide-1 (GLP-1) activation stimulates insulin secretion and may prevent atherosclerosis by increasing eNOS synthesis. However, there is paucity of information on the effect of GLP-1 activation on ET-1 expression. This study was conducted to address this issue.

Methods and Results

Human umbilical vein endothelial cells (HUVECs) were incubated with different concentrations of liraglutide, a GLP-1 agonist, and the expression of ET-1 and eNOS and activity of NF-κB were measured. Liraglutide, in a concentration-dependent manner, was observed to promote eNOS expression and to inhibit ET-1 expression both at mRNA and protein levels. Liraglutide also inhibited NF-κB phosphorylation and its translocation from cytoplasm to the nucleus. To ascertain the role of NF-κB activation in the altered expression of ET-1 and eNOS, we treated HUVECs with phorbol 12-myristate 13-acetate (PMA). PMA activated NF-κB and reversed the effects of liraglutide on eNOS and ET-1 expression. The effects of PMA on eNOS and ET-1 expression were reproduced in experiments wherein cells were treated with TNF-α. Further, we measured the generation of IL-6, apowerful pro-inflammatory molecule released by endothelial cells, as a measure of cellular function. PMA increased IL-6 generation, and this effect was blocked by liraglutide.

Conclusions

Our observations suggest liraglutide suppresses ET-1 expression by inhibiting the phosphorylation of NF-κB. This mechanism may underlie the potential anti-atherosclerotic effects of GLP-1 agonists. Of note, these effects of liraglutide were seen in an in vitro setting wherein cellular glucose concentrations were elevated.