地塞米松通过影响Caspase-3及NF-κB表达加重脑缺血再灌注凋亡作用

目的研究地塞米松是否加重脑缺血再灌注细胞凋亡及核转录因子NF-κB、Caspase-3在此过程中的作用.方法采用线栓法建立大鼠局灶性脑缺血再灌注模型.缺血1 h后生理盐水组腹腔注射0.9%氯化钠注射液(0.5mL),地塞米松组腹腔注射地塞米松[0.5 mg/(kg·d)].利用TUNEL法研究凋亡细胞的变化,应用免疫组化、原位杂交法检测NF-κB蛋白、Caspase-3 mRNA的表达.结果各缺血组凋亡细胞显著增多.地塞米松组各时点凋亡细胞数多于生理盐水组,NF-κB活化程度均明显低于生理盐水组,Caspase-3染色阳性细胞数明显高于生理盐水组(P＜0.01).结论地塞米松加重大鼠局灶性脑缺血再灌注损伤可能是与其阻碍NF-κB蛋白活化与上调Caspase-3 mRNA表达,并继而加重脑神经细胞凋亡的机制有关.     

NF-κB在多柔比星所致大鼠心肌损伤中的作用及褪黑素的治疗作用

目的探讨NF-κB在多柔比星(Dox)心肌病中的作用及褪黑素(MT)的干预作用。方法30只雄性SD大鼠随机分为正常对照组、Dox模型组、Dox+MT组。免疫组织化学法检测NF-κB的活性,分光光密度法检测心肌组织中一氧化氮(NO)含量和诱导型一氧化氮合酶(iNOS)活性,TUNEL法检测心肌细胞凋亡。结果与正常对照组相比,NF-κB在Dox模型组显著活化,MT可抑制NF-κB的激活(P<0.05);与正常对照组相比,Dox组NO含量、iNOS活性和心肌细胞凋亡率显著升高(P<0.05),MT干预后均显著降低。结论NF-κB参与心肌氧化应激损伤,促进心肌细胞凋亡。MT可抑制NF-κB活化,减少自由基的生成,抑制心肌细胞凋亡,对Dox心肌病具有保护作用。     

PDTC对重症急性胰腺炎大鼠腺胞细胞凋亡的影响

目的观察胰腺腺胞细胞凋亡在大鼠重症急性胰腺炎中的表达。方法大鼠60只随机分为对照组、模型组、干预组。造模开始第3、6、12 h麻醉后左心室采血处死,取胰腺组织;TUNEL法进行细胞凋亡检测,双抗体夹心ABC-ELISA法测定NF-κB及Bcl-2的含量。结果与对照组比较,模型组大鼠血清淀粉酶、胰腺组织病理学评分、血浆NF-κB、Bcl-2含量显著增高(P<0.01),NF-κB与Bcl-2呈正相关关系(r=0.435,P<0.05);与模型组比较,干预组血淀粉酶升高幅度和NF-κB、Bcl-2含量明显降低,细胞凋亡指数增加(P<0.01)。结论 NF-κB激活介导上调Bcl-2参与L-精氨酸诱导的SAP发生、发展过程;PDTC干预NF-κB激活使大鼠胰腺腺胞细胞凋亡增加,改善胰腺病理损伤。     

丹皮酚通过抑制NF-κB信号通路诱导Tca8113细胞凋亡

目的 研究丹皮酚对核因子κB（NF-κB）信号通路的影响,探讨其诱导肿瘤细胞凋亡的分子机制。方法 将丹皮酚以不同浓度及不同时间作用于人舌鳞癌Tca8113细胞,应用MTT法观察不同浓度丹皮酚在不同作用时间下对Tca8113细胞增殖的抑制作用,Hoechst 33342荧光染色及流式细胞仪检测细胞凋亡情况,Western blot法检测凋亡相关蛋白Bax和Bcl-2,以及NF-κB信号通路组分中IκBα和p-IκBα的表达情况,并采用凝胶电泳迁移率检测（EMSA）对NF-κB活性进行测定。结果 经丹皮酚作用后,Tca8113细胞生长受到明显抑制,并呈明显的时间、剂量依赖效应关系。丹皮酚有明显诱导Tca8113细胞凋亡的作用,Western Blot 以及EMSA检测结果显示,丹皮酚上调Tca8113细胞中Bax与IκBα的表达,下调Bcl-2的表达,并能下调IκBα磷酸化及NF κB活性。结论 丹皮酚能够抑制NF-κB信号转导通路,进而抑制Tca8113细胞的增殖并诱导其凋亡。     

文冠果壳苷诱导人恶性黑色素瘤A375.S2细胞的凋亡及机制

目的观察文冠果壳苷对人恶性黑色素瘤A375.S2细胞增殖抑制作用及诱导凋亡的机理。方法采用四甲基噻唑蓝法(MTT法)检测化合物对细胞的生长抑制作用,光学显微镜及荧光显微镜观察细胞形态学变化,免疫印迹法(Western blotting)检测p-p38、p38、核转录因子-κB(nuclear factor kappa B,NF-κB)p65及核转录抑制因子-κB(nuclear factor kappa B inhibitor,I-κB)蛋白表达水平,检测细胞核内NF-κB p65表达水平。结果文冠果壳苷可浓度依赖性地抑制A375.S2细胞增殖,并优于5-氟尿嘧啶(5-FU);10μmol·L-1文冠果壳苷作用于A375.S2细胞,形态学观察发现明显的凋亡小体和核固缩;Western blotting检测发现文冠果壳苷可时间依赖性地降低p-p38、p38、NF-κB p65及I-κB的蛋白表达水平;文冠果壳苷抑制NF-κB p65自细胞浆到细胞核的转位。结论文冠果壳苷可能通过抑制NF-κB和p38的活化诱导人恶性黑色素瘤A375.S2细胞凋亡。     

以TNF-α刺激A549细胞构建急性肺损伤细胞模型

目的构建急性肺损伤体外细胞模型。方法以TNF-α10ng/mL刺激肺泡Ⅱ型上皮A549细胞,采用酶联免疫吸附法检测细胞上清液中IL-4、IL-1β浓度,比色法检测丙二醛浓度、总超氧化物歧化酶活力,RT-PCR及免疫印迹法分别检测NF-κB m RNA及蛋白的表达水平,流式细胞术检测细胞凋亡率。结果以TNF-α刺激A549细胞,细胞上清液IL-1β、IL-4浓度上升;细胞内丙二醛增多,超氧化物歧化酶活力下降;NF-κB在基因及蛋白水平表达上调(P<0.05)。结论以TNF-α刺激肺泡Ⅱ型上皮A549细胞可诱导炎症反应放大、氧化应激失衡、NF-κB通路活化、细胞凋亡增加,符合急性肺损伤的主要特点,可作为ALI体外细胞模型。     

促红细胞生成素抗高糖体外培养大鼠视网膜神经细胞凋亡的NF-κB机制

目的研究促红细胞生成素(EPO)抗高糖体外培养大鼠视网膜神经细胞凋亡的NF-κB机制。方法胰酶消化法提取大鼠视网膜神经细胞进行原代培养,随机分为对照组、模型组及不同浓度EPO治疗组,培养48 h后TUNEL法测定细胞凋亡情况,免疫细胞化学法(SP法)测定NF-κB蛋白表达。结果细胞凋亡检测显示模型组同对照组相比凋亡细胞明显增多(P<0.01),各EPO治疗组同模型组相比凋亡细胞明显减少(P<0.01);免疫细胞化学法见NF-κB蛋白在对照组仅有极少量表达,在模型组呈弱阳性表达,而各EPO治疗组较模型组表达明显增强(P<0.01)。随着EPO浓度从5 kU.L-1增加到40 kU.L-1,视网膜神经细胞的凋亡明显减少,NF-κB蛋白的表达明显上升,呈一定浓度依赖性。结论高糖状态是引发大鼠视网膜神经细胞发生凋亡的损伤性因素之一,EPO能抑制高糖引发的凋亡,发挥神经保护作用,其机制可能是通过上调NF-κB的表达来实现,这为临床早期糖尿病视网膜病变的治疗提供了理论依据。     

NF-kB/IκB-α信号通路对ATRA诱导HL-60细胞凋亡的影响

目的探讨NF-kB/IκB-α信号通路对全反式维甲酸(ATRA)诱导HL-60细胞凋亡的影响。方法将HL-60细胞与不同浓度的ATRA共同孵育,MTT法观察ATRA对细胞增殖作用,流式细胞术及电镜分析细胞凋亡,Western-Blot检测NF-κB及IκB-α的变化。结果MTT显示ATRA呈时间-剂量依赖方式抗HL-60细胞增殖,作用72h流式细胞术DNA直方图上出现典型的亚二倍体凋亡峰,透射电镜下见细胞核染色质致密浓缩,凋亡小体形成,Western-Blot产物显示HL-60细胞NF-κBp65下降,而IκB-α上升。结论ATRA能抗HL-60细胞增殖诱导凋亡,该过程可能与抑制IκB-α的降解阻止NF-κB的活化有关。     

胡黄连苷Ⅱ对大鼠脑缺血/再灌注损伤NF-κB和I-κB的干预作用

目的研究胡黄连苷Ⅱ对大鼠脑缺血/再灌注后核转录因子κB(NF-κB)和NF-κB抑制因子(I-κB)表达的影响。方法应用线栓法建立大鼠大脑中动脉闭塞再灌注模型,经尾静脉注射胡黄连苷Ⅱ(10mg·kg-1)和丹参素钠(10mg·kg-1)干预治疗,原位TUNEL检测神经细胞凋亡,免疫组化检测NF-κB和I-κB的表达,ELISA法检测脑组织匀浆NF-κB和I-κB的含量。结果假手术组大鼠皮质、纹状体和海马区脑组织NF-κB和I-κB弱表达,TUNEL阳性细胞数量较少,散在分布。阴性对照组大鼠各区脑组织TUNEL阳性细胞数量较假手术组均增多,NF-κB和I-κB表达增强,脑组织匀浆NF-κB和I-κB增高(P<0.05)。阳性对照组和胡黄连苷组各区脑组织TUNEL阳性细胞数量,NF-κB和I-κB表达(A值)及脑组织匀浆NF-κB和I-κB含量均低于阴性对照组(P<0.05),阳性对照组与胡黄连苷组比较,各指标差异均无显著性(P>0.05)。结论胡黄连苷Ⅱ可能通过下调NF-κB和I-κB的表达,抑制脑缺血/再灌注损伤的炎症反应导致的神经细胞凋亡。     

NF-κB/IκB在二苯乙烯苷抑制过氧化氢诱导内皮细胞凋亡中的表达变化

目的探讨二苯乙烯苷(TSG)对过氧化氢(H2O2)诱导人脐静脉内皮细胞凋亡及对核因子κB(NF-κB)、NF-κB抑制因子(IκB)基因表达的影响。方法体外培养人脐静脉内皮细胞,实验分为对照组、H2O2组、TSG组,采用Ho-echst 33258染色观察细胞凋亡形态,MTT法检测细胞增殖率,流式细胞术检测细胞凋亡率,RT-PCR检测NF-κB与IκB mR-NA表达,Western blot检测NF-κB p65、IκB蛋白表达。结果与对照组比较,H2O2组凋亡细胞数增多,细胞凋亡率增加,细胞增殖降低;NF-κB mRNA和蛋白表达增加,IκB mRNA和蛋白表达降低,差异均有显著性(P<0.01)。经TSG预处理后,细胞的增殖率较H2O2组增加,细胞凋亡率减少;NF-κBmRNA和蛋白表达减少,IκB mRNA和蛋白表达增加(P<0.01)。结论二苯乙烯苷能抑制H2O2诱导的人脐静脉内皮细胞凋亡,其作用机制可能与调节NF-κB/IκB表达有关。     

NF-κB在甘精胰岛素拮抗胰岛β细胞脂性凋亡中的作用

目的探讨①核因子κB(NF-κB)在游离脂肪酸(FFA)诱导的胰岛β细胞凋亡中的作用;②观察甘精胰岛素(glargine)对FFA诱导的胰岛β细胞凋亡的拮抗作用是否与NF-κB有关。方法Western blot检测FFA对RIN-m细胞NF-κB活性的影响,以及glargine或普通胰岛素(RI)和FFA共同孵育细胞对NF-κB活性的影响;流式细胞仪测定NF-κB抑制剂Bay-117082对FFA诱导的RIN-m细胞凋亡的影响,以及Bay-117082对glargine和RI的抗凋亡作用的影响。结果NF-κB活性在FFA孵育后增加,抑制NF-κB活性使FFA诱导的凋亡增加;glargine和RI增加FFA所导致的NF-κB激活,抑制NF-κB活性能阻断glargine及RI的抗凋亡作用。结论NF-κB在FFA诱导胰岛β细胞凋亡时被激活,NF-κB激活对FFA诱导的凋亡可能起拮抗作用;glargine和RI的抗凋亡作用可能通过NF-κB途径。     

重症急性胰腺炎大鼠海马NF-κB与Caspase-3的表达

目的研究大鼠重症急性胰腺炎(SAP)合并脑损伤时脑组织海马区核因子-κB p65(NF-κB p65)和半胱天冬氨酸蛋白酶3(Caspase-3)的表达及与脑损伤的关系。方法 4%牛磺胆酸钠逆行注入大鼠胰胆管建立SAP模型(SD大鼠32只,SAP组),对照组32只SD大鼠应用生理盐水(NS组)。尼氏染色检测脑组织海马区神经元损伤情况,免疫组化检测海马组织NF-κB p65和Caspase-3的蛋白表达。结果与NS组比较,在3、6、12h,SAP组NF-κB p65和Caspase-3的表达均明显增加,6h达高峰(P<0.05),且海马神经元损伤也明显加重(P<0.05)。结论 NF-κB p65参与了SAP大鼠脑损伤的发生、发展;NF-κB p65可能通过促进Caspase-3的表达来加速神经元凋亡。     

PCSK9抑制剂在ox-LDL诱导HUVECs损伤中的保护作用研究

目的　探讨人类枯草溶菌素转化酶9（PCSK9）抑制剂对氧化型低密度脂蛋白（ox-LDL）导致的人脐静脉内皮细胞（HUVECs）损伤的保护机制。方法　对数生长期HUVECs细胞分为Control组（正常培养）,ox-LDL组（50 mg/L ox-LDL诱导24 h）,低、中、高剂量PCSK9抑制剂组（分别用5、10、20 μmol/L PCSK9抑制剂预处理24 h,再加入50 mg/L ox-LDL诱导24 h）。采用CCK-8法检测各组细胞活性并计算细胞存活率,实时荧光定量PCR（qPCR）和酶联免疫吸附测定（ELISA）法检测细胞或细胞培养上清液中肿瘤坏死因子（TNF）-α,白细胞介素（IL）-6和单核细胞趋化蛋白（MCP）-1的转录和分泌水平;流式细胞术检测细胞凋亡情况。Western blot检测细胞凋亡相关蛋白（Bax、Bcl-2、Cleaved-Caspase-3）和核因子（NF）-κB通路相关蛋白的表达水平。结果　与Control组比较,ox-LDL组细胞存活率下降,TNF-α、IL-6和MCP-1转录及分泌水平升高,细胞凋亡率升高,促凋亡蛋白Bax、Cleaved-Caspase-3表达上调,抗凋亡蛋白Bcl-2下调,磷酸化NF-κB（p-NF-κB）水平上调;同时NF-κB在细胞核内表达上调,胞质中表达下调。中、高剂量PCSK9抑制剂处理后,与ox-LDL组比较,细胞存活率升高,TNF-α、IL-6和MCP-1转录和分泌水平下降,细胞凋亡率下降, Bax、Cleaved-Caspase-3表达下调,Bcl-2表达上调,p-NF-κB水平下降。进一步分析发现,PCSK9抑制剂下调ox-LDL导致的HUVECs细胞核中NF-κB表达,上调胞质中NF-κB的表达（P＜0.05）。结论　PCSK9抑制剂可以抑制ox-LDL导致的HUVECs炎症反应和细胞凋亡,发挥内皮功能保护作用。     

NF-kappaB inhibition improves the sensitivity of human glioblastoma cells to 5-aminolevulinic acid-based photodynamic therapy

Glioblastoma constitute the most frequent and deadliest brain tumors of astrocytic origin. They are very resistant to all current therapies and are associated with a huge rate of recurrence. In most cases, this type of tumor is characterized by a constitutive activation of the nuclear factor-kappaB (NF-κB). This factor is known to be a key regulator of various physiological processes such as inflammation, immune response, cell growth or apoptosis. In the present study, we explored the role of NF-κB activation in the sensitivity of human glioblastoma cells to a treatment by 5-aminolevulinic acid (5-ALA)-based photodynamic therapy (PDT). 5-ALA is a physiological compound widely used in PDT as well as in tumor photodetection (PDD). Our results show that inhibition of NF-κB improves glioblastoma cell death in response to 5-ALA-PDT. We then studied the molecular mechanisms underlying the cell death induced by PDT combined or not with NF-κB inhibition. We found that apoptosis was induced by PDT but in an incomplete manner and that, unexpectedly, NF-κB inhibition reduced its level. Oppositely PDT mainly induces necrosis in glioblastoma cells and NF-κB is found to have anti-necrotic functions in this context. The autophagic flux was also enhanced as a result of 5-ALA-PDT and we demonstrate that stimulation of autophagy acts as a pro-survival mechanism confering protection against PDT-mediated necrosis. These data point out that 5-ALA-PDT has an interesting potential as a mean to treat glioblastoma and that inhibition of NF-κB renders glioblastoma cells more sensitive to the treatment.     

Phillyrin protects mice from traumatic brain injury by inhibiting the inflammation of microglia via PPARγ signaling pathway

The neuroinflammatory response induced by microglia plays a vital role in causing secondary brain damage after traumatic brain injury (TBI). Previous studies have found that the improved regulation of activated microglia could reduce neurological damage post-TBI. Phillyrin (Phi) is one of the main active ingredients extracted from the fruits of the medicinal plant Forsythia suspensa (Thunb.) with anti-inflammatory effects. Our study attempted to investigate the effects of phillyrin on microglial activation and neuron damage after TBI. The TBI model was applied to induce brain injury in mice, and neurological scores, brain water content, hematoxylin and eosin staining and Nissl staining were employed to determine the neuroprotective effects of phillyrin. Immunofluorescent staining and western blot analysis were used to detect nuclear factor-kappa B (NF-κB) and peroxisome proliferator–activated receptor gamma (PPARγ) expression and nuclear translocation, and the inflammation-related proteins and mRNAs were assessed by western blot analysis and quantitative real-time PCR. The results revealed that phillyrin not only inhibited the proinflammatory response induced by activated microglia but also attenuated neurological impairment and brain edema in vivo in a mouse TBI model. Additionally, phillyrin suppressed the phosphorylation of NF-κB in microglia after TBI insult. These effects of phillyrin were mostly abolished by the antagonist of PPARγ. Our results reveal that phillyrin could prominently inhibit the inflammation of microglia via the PPARγ signaling pathway, thus leading to potential neuroprotective treatment after traumatic brain injury.     

An antitumor peptide from Musca domestica pupae (MATP) induces apoptosis in HepG2 cells through a JNK-mediated and Akt-mediated NF-κB pathway

An antitumor peptide from Musca domestica pupae (MATP) was seen to inhibit proliferation and induce apoptosis in cancer cells in our previous investigation. However, the molecular mechanisms involved in MATP-induced apoptosis are still uncharacterized in the human liver cancer cell line HepG2. The present study was undertaken to elucidate the signaling events in MATP-induced apoptosis of HepG2 cells. In this study, the sustained activation of phosphorylated c-Jun N-terminal kinase (JNK) and the obvious inactivation of phosphorylated Akt(Ser473), which prevented IκBα from degeneration, were induced by MATP. Simultaneously, the apoptosis induced by MATP was reversed by SP600125 (a JNK inhibitor) whereas it was aggravated by LY294002 (an Akt inhibitor). These results proved that JNK and Akt independently participated in the apoptosis of HepG2 cells, which were treated with MATP. Moreover, the activation of phosphorylated JNK together with the inactivation of phosphorylated Akt(Ser473) restrained nuclear factor-κB (NF-κB p65) from entering the nucleus. The apoptosis induced by MATP was increased by pyrrolidine dithiocarbamate (NF-κB p65 inhibitor) and the restriction of NF-κB p65 from entering the nucleus induced the decrease of Bcl-2. Simultaneously, MATP induced the increase of Bax, but this mechanism did not depend on the decrease of NF-κB p65 in the nucleus. The release of cytochrome c from the mitochondria, which intensified the expression of caspase-9 and caspase-3, was enhanced by the increase in Bax-to-Bcl-2 expression ratio. The apoptosis of HepG2 cells was induced ultimately by the increase in caspase-3. Taken together, these findings suggest that MATP-induced apoptosis through a JNK-mediated and Akt-mediated NF-κB pathway.     

A novel pentamethoxyflavone down-regulates tumor cell survival and proliferative and angiogenic gene products through inhibition of IκB kinase activation and sensitizes tumor cells to apoptosis by cytokines and chemotherapeutic agents

Most anticancer drugs have their origin in traditional medicinal plants. We describe here a flavone, 5,3'-dihydroxy-3,6,7,8,4'-pentamethoxyflavone (PMF), from the leaves of the Thai plant Gardenia obtusifolia, that has anti-inflammatory and anticancer potential. Because the nuclear factor-κB (NF-κB) pathway is linked to inflammation and tumorigenesis, we investigated the effect of PMF on this pathway. We found that PMF suppressed NF-κB activation induced by inflammatory agents, tumor promoters, and carcinogens. This suppression was not specific to the cell type. Although PMF did not directly modify the ability of NF-κB proteins to bind to DNA, it inhibited IκBα (inhibitory subunit of NF-κB) kinase, leading to suppression of phosphorylation and degradation of IκBα, and suppressed consequent p65 nuclear translocation, thus abrogating NF-κB-dependent reporter gene expression. Suppression of the NF-κB cell signaling pathway by the flavone led to the inhibition of expression of NF-κB-regulated gene products that mediate inflammation (cyclooxygenase-2), survival (XIAP, survivin, Bcl-xL, and cFLIP), proliferation (cyclin D1), invasion (matrix metalloproteinase-9), and angiogenesis (vascular endothelial growth factor). Suppression of antiapoptotic gene products by PMF correlated with the enhancement of apoptosis induced by tumor necrosis factor-α and the chemotherapeutic agents cisplatin, paclitaxel, and 5-flurouracil. Overall, our results indicate that PMF suppresses the activation of NF-κB and NF-κB-regulated gene expression, leading to the enhancement of apoptosis. This is the first report to demonstrate that this novel flavone has anti-inflammatory and anticancer effects by targeting the IKK complex.