阿司匹林抑制肿瘤坏死因子α诱导的人脐静脉内皮细胞分形趋化因子表达

背景 分形趋化因子通过介导炎症细胞的趋化与血管内皮损伤相关,阿司匹林具有抗炎作用,抑制多种细胞因子表达,其对分形趋化因子的影响尚无报道.目的 探讨阿司匹林对肿瘤坏死因子α(TNF-α)刺激的人脐静脉内皮细胞(HUVEC)分形趋化因子表达的影响和作用机制.方法 将HUVEC随机分为:空白组(无TNF-α刺激和药物干预),TNF-α刺激组,TNF-α PDTC干预组(PDTC系核因子κB的特异性活性抑制剂),TNF-α NS398干预组(NS398是COX-2的特异性活性抑制剂).TNF-α 阿司匹林0 02 mol/L干预组,TNF-α 阿司匹林0 2 mol/L干预组,TNF-α 阿司匹林1 mol/L干预组,TNF-α 阿司匹林5 mol/L干预组,共8组,每组3例.分别用RT-PCR法和Western blot法检测各组细胞分形趋化因子(分形素)和核因子κB p65(NF-κB p65)的mRNA水平和蛋白表达.结果 1)4 μg/L TNF-α使HUVEC的分形趋化因子mRNA水平和蛋白表达明显增加(P<0 01).2)阿司匹林浓度依赖性抑制TNF-α诱导的HUVEC分形趋化因子mRNA水平和蛋白表达(P<0 01);阿司匹林浓度依赖性地抑制HUVEC的NF-κB p65 mRNA水平和蛋白表达(P<0 01).3)PDTC抑制TNF-α诱导的HUVEC分形趋化因子mRNA水平和蛋白表达(均P<0 01).结论 阿司匹林通过NF-κB p65途径抑制TNF-α诱导的HUVEC 分形趋化因子mRNA水平和蛋白表达,并可能借此发挥抗动脉粥样硬化作用.     

NF-κB在TNF-α致人脐静脉内皮细胞凋亡中的作用

目的研究核转录因子-κB（nuc lear factor-κB,NF-κB）在TNF-α诱导培养的人脐静脉内皮细胞凋亡过程中的作用。方法体外培养人脐静脉内皮细胞,并用10 ng/m l的TNF-α进行诱导,不同时间段观察NF-κB活性、NF-κB抑制物IκBα表达以及细胞凋亡的情况,EMSA测定NF-κB活性,W estern-b lot检测IκBα的表达情况;Tunel法检测细胞凋亡;并用NF-κB的抑制剂PDTC预处理细胞后来观察TNF-α诱导细胞凋亡的情况。结果TNF-α以时间依赖性诱导人脐静脉内皮细胞凋亡,NF-κB的活性在处理后10 m in开始增强,2 h后恢复正常,IκBα的表达在10m in开始下降,2 h恢复正常;PDTC能抑制TNF-α诱导的凋亡。结论TNF-α在诱导体外培养的人脐静脉内皮细胞时,IκBα降解,NF-κB激活,从而引起细胞的凋亡。     

肿瘤坏死因子-α对单核细胞妊娠相关血浆蛋白A表达的影响及调节机制

目的探讨肿瘤坏死因子-α(TNF-α)对人外周血单核细胞妊娠相关血浆蛋白(PAPP)-A蛋白和mRNA表达的影响及其机制。方法采用密度梯度离心法分离及培养人外周血单核细胞,采用Western印迹法和实时荧光定量PCR法观察TNF-α诱导单核细胞PAPP-A蛋白和mRNA表达的时间及剂量效应。采用TransAMTM技术检测TNF-α对单核细胞NF-κB活性的影响。此外观察给予核转录因子κB(NF-κB)抑制剂BAY11-70682预处理后,TNF-α对单核细胞PAPP-A表达的影响。结果 TNF-α(100 ng/ml)刺激单核细胞后,PAPP-A的蛋白和mRNA表达分别在8 h和2 h达高峰,且呈剂量依赖性诱导单核细胞的PAPP-A表达。TNF-α可显著增加单核细胞的磷酸化NF-κB p65水平,在给与BAY11-70682预处理后,TNF-α诱导PAPP-A表达的作用受到抑制。结论促炎因子TNF-α通过激活NF-κB途径上调单核细胞PAPP-A的蛋白和基因表达,这可能是急性冠脉综合征(ACS)患者血清PAPP-A升高的机制之一。     

TNF-α诱导脑胶质瘤细胞凋亡过程中NF-κB、IκB活性的研究

目的探讨核转录因子-κB(NF-κB)及其抑制因子(IκB)在肿瘤坏死因子-α(TNF-α)诱导人脑胶质瘤细胞株U 251细胞凋亡过程中生物活性的变化。方法应用流式细胞仪检测TNF-α对U-251细胞生长的抑制和诱导凋亡作用。用免疫组化方法检测肿瘤细胞p65的表达,用W estern b lot检测IκB蛋白的变化。结果TNF-α可诱导U 251细胞凋亡,激活细胞中p65并诱导IκB降解;抗氧化剂二硫碳吡咯烷醇(PDTC)可抑制TNF-α诱导的IκB的降解及NF-κB的激活,增强TNF-α诱导U 251细胞的凋亡。结论TNF-α在诱导U 251细胞凋亡的过程中可激活NF-κB。抑制NF-κB活性,可增强TNF-α诱导细胞凋亡的作用。     

脂多糖诱导肺微血管内皮细胞炎性损伤机制的探讨

目的 探讨脂多糖诱导的肺微血管内皮细胞( PMVECs)炎性反应及可能的机制.方法 分离培养SD大鼠肺微血管内皮细胞,将其分为对照组和LPS (0.01、0.1、1、10 mg/L)干预组.酶联免疫吸附法检测细胞间黏附分子-1( ICAM-1),放射免疫法检测肿瘤坏死因子-α(TNF-α)和白细胞介素-8 (IL-8)的水平,实时荧光定量PCR检测TLR-4 mRNA的表达;蛋白质免疫印迹法检测核转录因子-κB (NF-κB)抑制蛋白IκB-α和NF-κB p65蛋白水平以及免疫细胞化学染色(NF-κB p65)观察NF-κB的活性变化.结果 与对照组比较,LPS组分泌的细胞因子显著增加并呈剂量依赖性;以10 mg/L的LPS刺激PMVECs,3种细胞因子于2、6和12 h均升高;ICAM-1、TNF-α于2h达分泌高峰,IL-8于12 h达分泌高峰;2 h TLR-4 mRNA表达明显增高达峰值,并持续12 h(分别为4.34±1.42、3.62+1.45和3.32±1.36),均高于对照组(1.00±0.00),差异有统计学意义(均P＜0.05);LPS刺激0.5、2、6和12 h后,NF-κB的活性显著增加,表现为抑制蛋白IκB-α迅速降解,p65蛋白同步释出并转入细胞核内.结论 LPS刺激PMVECs释放细胞因子,其效应并呈剂量依赖性,可能是通过激活TLR-4-NF-κB信号通路诱导了PMVECs的炎性损伤.     

铜绿假单胞菌肺炎大鼠核因子-κB表达及二硫代氨基甲酸吡咯烷对其的影响

目的探讨NF-κB及其诱导TNFα在大鼠铜绿假单胞菌（PA）肺炎中的表达及二硫代氨基甲酸吡咯烷（PDTC）对其的影响。方法72只SD大鼠分为健康对照组、PA组、PDTC干预组。每组24只。PA组大鼠制作PA模型,PDTC干预组制作PA模型前腹腔注射PDTC200mg／kg体重。PA组、PDTC干预组接种铜绿假单胞菌悬液0．2ml（6×10^8CFU／m1）。观察大鼠肺组织形态学改变,免疫组化及Western blot检测肺组织NF-κB表达,RT-PCR检测肺组织TNFαmRNA表达。结果PA组大鼠肺组织明显充血、水肿,大量炎性细胞浸润;PDTC干预组大鼠肺组织充血、水肿等炎性表现较PA组明显减轻。PA组大鼠肺组织NF-κB表达阳性细胞明显增多,PDTC干预组NF—κB表达阳性细胞明显减少。Western blot显示,各时间点NF-κB表达不同,3h达高峰。RT—PCR显示,PA组TNFαmRNA高表达,以6h最为明显;PDTC干预组TNFαmRNA表达明显下调,与PA组相比,差异有统计学意义（P〈0．01）。结论NF-κB及其诱导的TNFα在PA肺炎中发挥重要作用,PDTC可能通过抑制NF-κB的活性减轻PA引起的肺损伤。     

Toll样受体4和核因子-κB信号通路在溶血磷脂酸致动脉粥样硬化中的作用

目的探讨Toll样受体4(TLR4)/NF-κB信号通路在溶血磷脂酸(LPA)致动脉粥样硬化中的作用。方法以不同浓度LPA(0¹0μmol/L)刺激人单核细胞株THP-1细胞4h,以及LPA 1μmol/L处理THP-1细胞不同时间(010μmol/L)刺激人单核细胞株THP-1细胞4h,以及LPA 1μmol/L处理THP-1细胞不同时间(0⁸h),荧光定量RT-PCR法测定TLR4mRNA表达,Western blot检测TLR4蛋白、细胞核NF-κB p65表达变化,ELISA法测定细胞因子TNF-α,随后在LPA 1μmol/L条件下,TLR4单抗干预THP-1细胞,观察其对LPA诱导的细胞核NF-κB p65表达及TNF-α分泌水平的影响。结果当LPA 1μmol/L时,TLR4mRNA和蛋白及细胞核NF-κB p65表达较0μmol/L、0.1μmol/L、0.5μmol/L、5μmol/L、10μmol/L LPA明显增高,差异有统计学意义(P<0.01)。LPA 1μmol/L处理THP-1细胞4h时,THP-1细胞TLR4mRNA和蛋白及细胞核NF-κB p65表达水平明显高于0、1、2、8h(P<0.01)。与TLR4单抗干预前比较,TLR4干预后LPA诱导的THP-1细胞NF-κB p65表达及TNF-α分泌水平明显升高,差异有统计学意义(P<0.01)。结论 LPA可显著上调THP-1细胞TLR4表达及促进NF-κB的活化,LPA致动脉粥样硬化作用可能部分是由TLR4/NF-κB信号途径介导的。     

丙泊酚对脂多糖诱导的小胶质细胞肿瘤坏死因子-α表达的影响

目的探讨丙泊酚能否通过抑制核因子(NF)-κB活化下调脂多糖(LPS)诱导的小胶质细胞肿瘤坏死因子(TNF)-α的表达。方法将BV2细胞分为4组即对照组、丙泊酚组、丙泊酚+LPS组和LPS组。在干预0 h和24 h时使用MTT法检测BV2细胞活性。在干预24 h后使用RTPCR法和Western印迹法对BV2细胞TNF-αmRNA和蛋白的表达水平进行检测;并使用Western印迹法对细胞NF-κB p65磷酸化水平(phospho-NF-κB p65/NF-κB p65比值)进行分析。结果在给予LPS干预24 h后BV2细胞活性明显降低(P均0.05);但丙泊酚+LPS组细胞活性较LPS组增加(P均0.05),同时对照组和丙泊酚组细胞活性无统计学差异(P均0.05)。与对照组相比较,在LPS干预24 h后BV2细胞TNF-αmRNA和蛋白的表达水平以及phospho-NF-κB p65/NF-κB p65比值均明显升高(P均0.05);但LPS组较丙泊酚+LPS组TNF-α表达的升高以及phospho-NF-κB p65/NF-κB p65比值的增加更加显著(P均0.05);同时对照组和丙泊酚组TNF-α表达水平和phospho-NF-κB p65/NF-κB p65比值无统计学差异(P均0.05)。结论丙泊酚可能通过抑制NF-κB的激活下调了BV2细胞TNF-α合成和释放。     

呼吸道合胞病毒感染巨噬细胞诱导炎性基因表达的部分机制研究

目的探讨呼吸道合胞病毒(RSV)感染巨噬细胞时前炎介质肿瘤坏死因子-α(TNF-α)和诱导型一氧化氮合酶(iNOS)的基因表达变化及其调控的相关机制,为研究RSV的致病机制及有效预防和治疗RSV疾病提供新的思路。方法以RSV感染RAW264.7巨噬细胞,并设立不同的感染时间点(1h、4h、8h、16h和24h),同时给予PDTC(核转录因子NF-κB的特异性抑制剂)处理。以紫外线灭活RSV(UV-RSV)来分析有传染性的病毒的感染变化。收集各组细胞,用Western blot法检测细胞核内活性NF-κBp65蛋白的表达,半定量RT-PCR法检测TNF-α和iNOS mRNA表达量。结果RSV感染4h后,细胞核内活性NF-κBp65蛋白、TNF-α和iNOS mRNA表达均明显升高,各指标的变化与正常对照相比,差异均有显著性,并且与RSV感染存在时间依赖关系。当加入PDTC抑制NF-κB的入核活化后,则可显著下调相应时间点的RSV感染升高的TNF-α和iNOS mRNA表达量,使其降低至基线水平。而UV-RSV感染后并不引起NF-κB蛋白、TNF-α和iNOS mRNA的表达量增加(P>0.05)。结论RSV感染巨噬细胞可诱导前炎基因TNF-α和iNOS的大量表达,其表达可能主要依赖NF-κB活化,并且与病毒复制有关。提示在RSV感染的巨噬细胞中,NF-κB活化对TNF-α和iNOS基因表达具有重要的正调控作用。     

TNF-α诱导脑胶质瘤细胞凋亡过程中NF-κB、IκB活性的研究

目的探讨核转录因子-κB（NF-κB）及其抑制因子（ⅠκB）在肿瘤坏死因子-α（TNF-α）诱导人脑胶质瘤细胞株U251细胞凋亡过程中生物活性的变化。方法应用流式细胞仪检测TNF-α对U-251细胞生长的抑制和诱导凋亡作用。用免疫组化方法检测肿瘤细胞p65的表达，用Western blot检测IκB蛋白的变化。结果TNF-α可诱导U251细胞凋亡，激活细胞中p65并诱导ⅠκB降解；抗氧化剂二硫碳吡咯烷醇（PDTC）可抑制TNF-α诱导的ⅠκB的降解及NF—κB的激活，增强TNF-α诱导U251细胞的凋亡。结论TNF-α在诱导U251细胞凋亡的过程中可激活NF—κB。抑制NF—κB活性。可增强TNF-α诱导细胞凋亡的作用。     

Nuclear factor-κB inhibition improves myocardial contractility in rats with cirrhotic cardiomyopathy

Background/Aims: Cytokines such as tumour necrosis factor (TNF-α) contribute to the pathogenesis of cirrhotic cardiomyopathy. Nuclear factor-κB (NF-κB) is crucial for cytokine regulation, and induces cardiac dysfunction in several heart disease models. We aimed to elucidate possible NF-κB involvement in cirrhotic cardiomyopathy. Methods: Rats were bile duct ligated (BDL) to produce cirrhosis; controls received sham operation. Animals were studied 4 weeks later. Two NF-κB inhibitors were used: pyrrolidine dithiocarbamate (PDTC) and Bay 11-7082. Four groups were studied in most protocols: sham control, sham+PDTC, BDL and BDL+PDTC. Additional contractility studies were performed with Bay 11-7082. Myocardial NF-κB and TNF-α expression was measured by Western blot and ELISA. The contractility of isolated cardiomyocytes was observed under direct microscopy. Results: Nuclear factor-κB and TNF-α levels were increased in cirrhotic hearts compared with controls. PDTC significantly reduced NF-κB activity and TNF-α expression in cirrhotic hearts; controls were unaffected. Cirrhotic cardiomyocytes showed decreased systolic and diatolic velocity compared with sham controls. Both PDTC and Bay 11-7082 restored contractile function in cirrhotic cardiomyocytes, but did not affect controls. Conclusions: Inhibition of the increased NF-κB activity in cirrhotic hearts was associated with improvement of attenuated cardiomyocyte contractility. NF-κB, via effects on cytokine expression, may contribute to the pathogenesis of cirrhotic cardiomyopathy.     

HDL和阿托伐他汀对oxLDL刺激下脂肪细胞炎症反应的影响

目的 观察高密度脂蛋白（HDL）及阿托伐他汀对氧化型低密度脂蛋白（oxLDL）刺激下3T3-L1脂肪细胞肿瘤坏死因子-α（TNFα）分泌及mRNA表达的影响,并探讨其可能的作用机制.方法 3T3-L1脂肪细胞促分化成熟后,oxLDL刺激脂肪细胞,给予不同浓度的HDL（10～100 μg/mL）和阿托伐他汀（0.1～10 μM）,及H-89（10 μM）＋HDL（100 μg/mL）干预,收集细胞,测定脂肪细胞TNFα水平、TNFα mRNA表达水平、核因子-κB（NF-κB）活性及NF-κB抑制单位（IκB）蛋白浓度.结果 oxLDL刺激使3T3-L1脂肪细胞TNFα分泌、mRNA表达水平及NF-κB活性明显增强.阿托伐他汀浓度依赖性降低TNFα 分泌及mRNA表达,抑制NF-κB活化.10 μM阿托伐他汀使oxLDL诱导的脂肪细胞TNFα mRNA表达降低56.5%,NF-κB活性减少41.2%.HDL也呈浓度依赖性抑制TNFα分泌及mRNA表达,降低NF-κB活性,减少IκB降解.与oxLDL刺激组比较,100 μg/ml HDL使TNFα mRNA表达降低64.5%,NF-κB活性减少49%,并明显增加IκB蛋白水平.HDL的这些抗炎效应能被蛋白激酶A（PKA）抑制剂（应放在H89第一次出现之处）H-89部分抑制.结论 HDL能抑制oxLDL诱导的3T3-L1脂肪细胞TNFα分泌和mRNA表达,PKA-IκB-NF-κB信号通路可能是其中作用途径之一,该效应不需要HDL与oxLDL的直接接触作用.阿托伐他汀亦通过NF-κB途径抑制oxLDL诱导的3T3-L1脂肪细胞TNFα分泌和mRNA表达.HDL的抗炎作用强度与阿托伐他汀相似.     

脂多糖诱导肺泡上皮细胞炎性损伤及损伤机制

目的 探讨细菌脂多糖(LPS)诱导的肺泡上皮细胞(AEC)炎症反应及可能的反应机制.方法 将人肺腺癌细胞系A549细胞株分为2组:对照组和LPS干预组,分别培养并于0.5 h、2 h、6 h和12 h时留取标本进行相关细胞因子检测.酶联免疫吸附法(ELISA)检测细胞间黏附分子-1(ICAM-1),放射免疫法检测肿瘤坏死因子-α(TNF-α)和白细胞介素-8(IL-8)的水平.实时荧光定量PCR检测TLR-4 mRNA的表达;蛋白质免疫印迹(Western blot)法检测核转录因子-κB(NF-κB)抑制蛋白IκBα和NF-κB p65蛋白水平,观察NF-κB的活性变化.结果 与对照组比较,LPS使AECs分泌的ICAM-1,TNF-α和IL-8于2 h、6 h和12 h均升高,ICAM-1,TNF-α于2 h、IL-8于12 h达分泌高峰;作用2 h后TLR-4 mRNA表达明显升高并达到峰值(27.88±13.31),6 h后(19.82±15.58)仍高于对照组(1.00±0.00),组间比较差异有统计学意义(P＜0.05),12 h时(12.86±11.45)组间比较差异无统计学意义(P＞0.05);NF-κB活性于刺激后0.5 h、2 h、6 h和12 h均明显增加,表现为抑制蛋白IκBα迅速降解,NF-κB p65蛋白同步释出并转入细胞核内.结论 LPS能够激活肺泡上皮细胞使其释放大量炎性因子,这一过程可能是通过激活TLR-4并进而激活NF-κB而诱导了AECs的炎性损伤.

Abstract：

Objective Lipopolysaccharide(LPS)can activate alveolar epithelial cells(AECs)and induce inflammatory injury.Toll-like receptor-4(TLR-4)is integrally involved in LPS signaling and plays a requisite role in the activation of NF-κB.NF-κB is a key intercellular signaling event that mediates cell inflammatory responses.The aim of the study wss to investigate in an in vitro model the inflammatory responses of AECs induced by LPS and the underlying mechanisms.Methods The study was performed on A549 cells(Human lung adenocarcinoma cell line).A549 cells were divided into 2 groups:a control group and a LPS stimulation group.Pminflammatory cytokines ICAM-1,TNF-α and IL-8 were detected by ELISA or radioimmunological methods.The expression of TLR-4 mRNA was detected by real time PCR.The activation of NF-κB was detected by Western blot(proteins of I-κBα and NF-κB p65).Results Compared with the control group.the ICAM-1 and TNF-α levels of the LPS-stimulated group were significantly higher,peaked after 2 h,and then gradually decreased at 6 and 12 h.IL-8 was also significantly increased after 2 h, which continued up to 12 h.The expression of TLR-4 mRNA in the LPS group was significantly higher,peaked after 2 h and gradually decreased at 6 and 12 h.NF-κB was activated after 0.5,2,6 and 12 h,indicated by the significant degradation of IκB-α and the significant release of NF-κB P65 and its subsequent translocation into the nucleus approximately synchronized.Conclusion The results demonstrate that LPS induced inflammatory injury in AECs via activating TLR-4 and subsequently NF-κB.     

Ghrelin inhibits IKKβ/NF-κB activation and reduces pro-inflammatory cytokine production in pancreatic acinar AR42J cells treated with cerulein

Background: Previous studies have provided conflicting results regarding whether the serum ghrelin concentration can reflect the severity of acute pancreatitis(AP). The present study examined the correlation between the serum ghrelin concentration and AP severity in animal models and investigated whether altered ghrelin expression in pancreatic acinar cells influences IKK β/NF-κ B signaling and pro-inflammatory cytokine production. Methods: Mild or severe AP was induced in rats by intraperitoneal injection of cerulein or retrograde cholangiopancreatic duct injection of sodium taurocholate, respectively. After successful model induction, serum ghrelin, tumor necrosis factor-α(TNF-α), and interleukin-6(IL-6) concentrations were determined by enzyme-linked immunosorbent assay, and IKK β/NF-κ B activation was assessed by immunohistochemistry. Subsequently, stable overexpression or knockdown of ghrelin in AR42 J cells was achieved by lentiviral transfection. After transfected cells and control cells were treated with cerulein for 24 h, the TNF-αand IL-1 β levels in the supernatants were determined by enzyme-linked immunosorbent assay, and the expression levels of p-p65, IKK β, and p-IKK β were detected by Western blotting. Results: In rat AP models, AP severity was correlated with increased IKK β/NF-κ B activation, proinflammatory cytokine production, and ghrelin secretion. The levels of pro-inflammatory cytokines TNF-αand IL-1 β as well as IKK β/NF-κ B signaling activity were increased upon knockdown of ghrelin in the AP acinar cell model and decreased with ghrelin overexpression. Conclusions: Serum ghrelin is related to the severity of AP. Ghrelin may play a protective role in the pathogenesis of AP by inhibiting the pro-inflammatory cytokines and the activation of the IKK β/NF-κ B signaling pathway.     

蛋白磷酸酶2A抑制剂对胰腺癌细胞活力的影响及其机制

目的 研究蛋白磷酸酶2A(PP2A)抑制剂对胰腺癌细胞系PANC-1活力的影响及其机制.方法 用PP2A抑制剂斑蝥素和冈田酸处理PANC-1细胞.通过Western印迹检测核因子(NF) -κB通路的激活程度.通过转染PP2A活性亚基cα(PP2A cα)表达质粒、NF-κB抑制蛋白激酶(IKK)α和NF-κB抑制蛋白(IκB)α的显性负性突变体、p65干扰质粒,分别从各环节阻断NF-κB通路,通过四甲基偶氮唑盐比色法(MTT法)检测细胞活力.结果 PP2A抑制剂可使IKKa磷酸化,进一步使IκBa磷酸化并降解,继而释放p65入核.过表达PP2Acα、IKKα显性负性突变体、IκBα显性负性突变体或干扰p65可分别使斑蝥素对细胞活力的抑制率下降(31.85±13.37)％、(23.48±8.98)％、(22.63±5.81)％、(20.88±3.24)％,使冈田酸对细胞活力的抑制率下降(40.17±11.65)％、(27.34±14.28)％、(24.85±3.39)％、(27.08±3.81)％.结论 PP2A抑制剂通过PP2A/IKKα/IκBα/p65依赖性通路发挥抗胰腺癌作用.