Increased expression and activity of MMP-9 in C-reactive protein- induced human THP-1 mononuclear cells is related to activation of nuclear factor kappa-B

The relation between the expression and activity of MMP-9 in C-reactive protein （CRP）-induced human THP-1 mononuclear cells and the activation of nuclear factor kappa-B （NF-κB） was studied to investigate the possible role of CRP in plaque destabilization. Human THP-1 cells were incubated in the presence of CRP at 0 （control group）, 25, 50 and 100 μg/mL （CRP groups） for 24 h. In PDTC （a specific NF-κB inhibitor） group, the cells were pre-treated with PDTC at 10 μmol/L and then with 100 μg/mL CRP. The conditioned media （CM） and human THP-1 cells in different groups were harvested. MMP-9 expression in CM and human THP-1 cells was measured by ELISA and Western blotting. MMP-9 activity was assessed by fluorogenic substrates. The expression of NF-κB inhibitor α （IκB-α） and NF-κB p65 was detected by Western blotting and ELISA respectively. The results showed that CRP increased the expression and activity of MMP-9 in a dose-dependent manner in the human THP-1 cells. Western blotting revealed that IiB-α expression was decreased in the cells with the concentrations of CRP and ELISA demonstrated that NF-κB p65 expression in the CRP-induced cells was increased. After pre-treatment of the cells with PDTC at 10 μmol/L, the decrease in IκB-α expression and the increase in NF-κB p65 expression in the CRP-induced cells were inhibited, and the expression and activity of MMP-9 were lowered too. It is concluded that increased expression and activity of MMP-9 in CRP-induced human THP-1 cells may be associated with activation of NF-κB. Down-regulation of the expression and activity of MMP-9 may be a new treatment alternative for plaque stabilization by inhibiting the NF-κB activation.     

Anisodamine Inhibits Engotoxin—induced Tissue Factor Expression in Human Endothelial Cells

By study on the effect of anisodamine on lipopolysaccharide-induced expression of tissue factor(TF) in vascular endothelial cells (EC),the mechanism of anisodamine antithrombosis,as well as in the treatment of bacteraemic shock was investigated.Human umbilical vein endothelial cells (HUVECs) were cultured by trypsin digestion method.TF activity was measured in the lysates of HUVEC by using a single step clotting assay.Specific mRNA expression was detected by Northern blotting.In order to evaluate a possible contribution of the nuclear factor (NF)-κB pathway on the effects observed,electrophoretic mobility shift assays (EMSA) were performed using nuclear extracts from HUVECs and NF-κB-binding oligonucleotides.The results showed that treatment of HUVEC with LPS resulted in a significant increase in TF activity.Anisodamine dose-dependently inhibited LPS-induced upregulation of TF.These effects was also confirmed on the level of specific TF mRNA expression by Northern blotting.Furthermore,EMSA showed that anisodamine completely abolished LPS-induced NF-κB DNA binding activity in nuclear extracts from HUVECs treated with LPS together with anisodamine.The results suggest that anisodamine counteracts endothelial cell activation by inhibiting LPS-induced TF expression in these cells.Its interference with the NF-κB pathway might-at least in part-contribute to this effect.The ability of anisodamine to counteract LPS effect on endothelial cells might be one underlying mechanism explaining its antithrombosis and efficacy in the treatment of bacteraemic shock.     

Inhibition of NF-κB by mutant IκBα enhances TNF-α-induced apoptosis in HL-60 cells by controlling bcl-xL expression

Backgound The aim of this study was to explore whether the inhibition of nuclear factor-κB (NF-κB)activation by mutant IκBα (S32,36→A) can enhance TNF-α-induced apoptosis of leukemia cells and to investigate the possible mechanism. Methods The mutant IκBα gene was transfected into HL-60 cells by liposome-mediated techniques. G418 resistant clones stably expressing mutant IκBα were obtained by the limiting dilution method. TNF-α-induced NF-κB activation was measured by electrophoretic mobility shift assay (EMSA). The expression of bcl-xL was detected by RT-PCR and Western blot after 4 hours exposure of parental HL-60 and transfected HL-60 cells to a variety of concentrations of TNF-α. The percentage of apoptotic leukemia cells was evaluated by flow cytometry (FCM). Results Mutant IκBα protein was confirmed to exist by Western blot. The results of EMSA showed that NF-κB activation by TNF-α in HL-60 cells was induced in a dose-dependent manner, but was almost completely inhibited by mutant IκBα repressor in transfected cells. The levels of bcl-xL mRNA and protein in HL-60 cells increased after exposure to TNF-α, but changed very little in transfected HL-60 cells. The inhibition of NF-κB activation by mutant IκBα enhanced TNF-α-induced apoptosis. Thecytotoxic effects of TNF-α were amplified in a time- and dose-dependent manner. Conclusions NF-κB activation plays an important role in the resistance to TNF-α-induced apoptosis. The inhibition of NF-κB by mutant IκBα could provide a new approach that may enhance the antileukemia effects of TNF-α or even of other cytotoxic agents.     

LPS-induced NF-κB activation requires Ca2+ as a mediator in isolated pancreatic acinar cells of rat

Objective To investigate the effect of Ca2+ on lipopolysaccharide (LPS)-induced NF-κB activation in pancreatic acinar cells and the role of NF-κB in LPS-induced acinar cell injury. Methods Male rat pancreatic acinar cells were isolated by collagenase digestion, then exposed to varying concentrations of LPS (from 1 to 20 mg/L) in the presence or absence of EGTA. At various time points (30 minutes, 1 hour, 2 hours, 4 hours and 10 hours) after treatment with the agents, cell viability was determined by MTT. Nuclear translocation of NF-κB’s subunit p65 was visualized by immunofluorescence staining and nuclei protein was extracted to perform EMSA which was used to assay the activity of NF-κB binding to the DNA sequence containing the recognition site of NF-κB. Results LPS induced cell damage in a time- and concentration-dependent manner while EGTA attenuated LPS-induced cell damage (P<0.05). NF-κB p65 immunofluorescence staining had increased intensity in the cytoplasm and indicated that nuclear translocation occurred within 30 minutes and its zenith was reached at 1 hour after LPS (10 mg/L) treatment. Testing of NF-κB DNA binding activity showed the same alteration phase as p65 immunofluorescence staining. NF-κB activation preceded the pathological alteration of pancreatic acinar cells. The Ca2+ chelator EGTA inhibited LPS-induced NF-κB activation. Conclusions NF-κB activation is an important early event in LPS-induced injury to pancreatic acinar cells. Ca2+ is an important mediator in the process of LPS-induced NF-κB activation.     

Homocysteine-induced Enhanced Expression of Tissue Factor in Human Vascular Smooth Muscle Cells

The homocysteine (Hcy)-induced tissue factor (TF) expression in human vascular smooth muscle cells (VSMCs) and the effect of Hcy on the activity of nuclear factor-kappaB (NF-кB) and the expression of inducible nitric oxide synthase (iNOS) were investigated. Human umbilical artery VSMCs were cultured by tissue explanting method, identified by α-actin immunohistochemistry, and incubated with different concentrations of Hcy/PTDC (NF-кB inhibitor). Semi-quantitative RT-PCR was performed to detect the expression of TF mRNA in VSMCs. Flow cytometry was used to assay the expression of TF protein on the surface of VSMCs and the expression of iNOS in VSMCs. Western blot was carried out to detect the expression of NF-кB protein in nuclei. The results showed that Hcy could induce VSMCs expressing TF mRNA significantly after the VSMCs were incubated with Hcy at concentrations of 10, 100, 500 μmol/L respectively. There was low expression level of TF protein on the surface of the resting VSMCs and Hcy could also induce VSMCs expressing TF pro- tein on the cell surface in different concentrations. Additionally, Hcy could rapidly induce the activation of NF-кB and this effect could be significantly inhibited by PDTC. Hcy alone could not induce the expression of iNOS in VSMCs. It was concluded that Hcy could significantly induce the expression of TF in VSMCs and enhance the activation of NF-ΚB, subsequently mediate TF gene expression and protein synthesis. NF-кB-mediated expression of TF in VSMCs might be the important mechanism of atherosclerosis and thrombosis induced by Hcy.     

Expression of NF-κB in hRPE Cells Stimulated by PDTC and IL-1β

The constitutive expression of nuclear-factor-κB (NF-κB) in human pigment epithelial (hRPE) cells cultivated in vitro and the possible changes when incubated with PDTC and IL-I were investigated. The synchronized hRPE cells in vitro were divided into two groups. In nonPDTC group, hRPE cells were exposed respectively to IL-1β and NS (for detecting the constitutive expressions of NF-κB in hRPE cells) ; In PDTC group, PDTC-pretreated hRPE cells were exposed respectively to IL-1β?Aand NS. (for detecting the constitutive expression of NF-κB in PDTC-pretreated hRPE cells). The expression of NF-κB in hRPE cells in two groups was detected by immunofluorescence stain and flow cytometry. The results showed that the constitutive expression of NF-κB in hRPE cells in vitro was 8.05 %, and increased to 30.26 % by IL-1β. After PDTC pretreatment, the constitutive expression of NF-κB in hRPE cells was decreased to 3.74%, and 3.66 % by IL-l,respectively. It was concluded that the expressions of NF-κB in hRPE cells could be increased significantly by IL-1βand depressed effectively by PDTC. Also, PDTC could significantly inhibit the activation of NF-κB induced by IL-1β.     

Effect of N-tosyl-L-phenylalanylchloromethyl Ketone on Tumor Necrosis Factor-alpha -induced NF-κB Activation and Apoptosis in U937 Cell Line

Summary: To investigate the effect of N-tosyl-L-phenylalanylchloromethyl ketone (TPCK) on tumor necrosis factor-alpha-induced NF-κB activation and apoptosis in U937 cell line, changes and subcellular localization of NF-κB/p65 and IκB-α were observed by fluorescencemicroscopy and expression and degradation of IκB-α by flow cytometry. The apoptosis of U937 cells was measured by flow cytometry and electrophoresis of DNA. Immunolfluorescence assay showed that NF-κB/p65,IκB-α only localized in cytoplasm. After TNF-α stimulation, p65 was localized only in nuclei, and IκB-α was only localized in cytoplasm and decreased. The changes of TNF-α stimulation were specifically inhibited by TPCK. Flow cytometry also revealed the downregulation of IκB-α protein during TNF-α-induced apoptosis and the down-regulation was specifically inhibited by TPCK. Flow cytometry also showed the apoptosis of U937 cells after TNF-α induction. DNA ladder can be detected in cells treated by TNF-α. It is concluded that degradation of IκB-α protein and NF-κB/p65 translocation occur during TNF-α-induced apoptosis of U937 cells, suggesting the activation of NF-κB.TPCK-sensitive protease plays an important role in the degradation of IκB-α protein induced by TNF-α in U937 cells. TPCK sensitive protease also plays an important role in the apoptosis of U937 cells induced by TNF-α.     

AGEs对老年大鼠内皮细胞NF-κB活性与Fn mRNA表达的影响

目的：探讨糖基化终末产物（AGEs）对老年大鼠内皮细胞中NF-κB活性及纤维结合蛋白fibronectin（Fn）mRNA表达的影响。方法：取24月龄的SD大鼠主动脉内皮细胞进行原代培养．实验分为3组。A组葡萄糖（5mmol／L）的对照组;B组AGEs（25mg／L,48h）处理组;C组AGEs（50mg／L．48h）处理组。采用荧光免疫化学法检测NF-κB活性和逆转录聚合酶链式反应（RT-PCR）检测Fn mRNA的表达。结果：与对照组相比,AGEs呈浓度依赖性地诱导NF-κB的激活（P〈0．05）和上调Fn mRNA表达（P〈0．05）。结论：AGEs呈浓度依赖性地诱导内皮细胞NF-κB的活化、Fn的基因表达上调,这可能与糖尿病慢性血管并发症的发生发展有关。     

N-乙酰半胱氨酸对脂多糖刺激人子宫平滑肌细胞白细胞介素8表达的影响

目的探讨N-乙酰半胱氨酸(NAC)对脂多糖(LPS)刺激离体培养的人晚期妊娠子宫平滑肌细胞IL-8表达和核转录因子(NF-κB)活性的影响。方法原代培养足月未临产的子宫平滑肌细胞,10μg/mL LPS与经浓度分别为0(生理盐水对照,NS)、5、10、15 mmol/L的NAC预处理的子宫平滑肌细胞作用8 h,以及10 mmol/L的NAC或NS预处理的子宫平滑肌细胞经LPS干预0 h、3 h、6 h、12 h、24 h、48 h,收集细胞免疫印迹检测NF-κB P65合成情况、RT-PCR检测IL-8 mRNA表达及上清液ELISA检测IL-8浓度。结果1NAC在5~15 mmol/L呈剂量依赖性抑制LPS刺激IL-8蛋白合成和mRNA表达。2随着NAC浓度由低至高,NF-κB P65合成由强到弱,差异有统计学意义(P<0.01),其变化趋势与IL-8 mRNA一致。结论NAC能抑制LPS刺激晚期妊娠子宫平滑肌细胞IL-8蛋白合成和基因表达,可能与其抑制NF-κB激活有关。     

趋化因子Fractalkine在血管紧张素II诱导内皮细胞ICAM-1表达中的作用

目的 研究Fractalkine（FKN）在血管紧张素II（Ang II）诱导内皮细胞表达细胞间黏附分子-1（ICAM-1）中的作用.方法 取人脐静脉内皮细胞（HUVECs）培养,分别给予低、高浓度（10-7 mol/L,10-6 mol/L）Ang II干预12、24、48 h,采用MTT检测内皮细胞活性,Western blot检测ICAM-1和FKN蛋白表达;小RNA转染内皮细胞后,用高浓度Ang II培养24 h并检测各组细胞FKN mRNA表达及ICAM-1和FKN蛋白表达.结果 Ang II可降低HUVECs活性并促进ICAM-1及FKN蛋白表达,高浓度AngII对内皮细胞活性影响较大;FKN siRNA转染可显著抑制FKN mRNA表达,且在高浓度Ang II作用24 h后,被转染细胞的FKN mRNA表达量仍显著低于阴性对照＋Ang II组（P＜0.05）,且ICAM-1及FKN蛋白表达显著减少.结论 Ang II可降低内皮细胞活性并促进内皮细胞ICAM-1和FKN蛋白表达,趋化因子FKN介导了Ang II诱导的内皮细胞ICAM-1蛋白表达过程.     

TGFβ1对人血管内皮细胞整合素β3及粘着斑激酶表达的影响

OBJECTIVE: To observe the effects of transforming growth factors beta 1 (TGF beta 1) on the expression of integrin beta 3 and the activity of focal adhesion kinase (FAK). METHODS: This study was performed on cultured human endothelial cells (EC) by using cell-ELISA and immunoprecipitation-tyrosine kinase assay respectively. RESULTS: Under the stimulus of TGF beta 1, there a dose-dependent increase in the expression of integrin beta 3 chain in the surface of EC. And after the cultured EC were treated with 5 ng/ml or 10 ng/ml TGF beta 1 for 6 or 24 hours, the FAK activity in EC increased significantly as compared with the control group (P < 0.05). CONCLUSION: The expression of integrin beta 3 and the activity of FAK on EC were regulated by TGF beta 1, and this regulation may be important in cell adherence, angiogenesis, and in the pathophysiology of atherosclerosis.     

NF-κB/IκB信号通路介导血管紧张素Ⅱ诱导的系膜细胞促炎性细胞因子表达

目的：探讨核因子—κB(NF—κB)／IκB信号通路在血管紧张素Ⅱ(AngⅡ)诱导的肾小球系膜细胞促炎性细胞因子表达中的作用。方法：应用核酸酶保护法检测系膜细胞肿瘤坏死因子α(TNF—α)、IL-1α和IL-1β mRNA表达；应用凝胶电泳迁移率和Western blot检测肾小球系膜细胞中NF—κB活化、p65亚基核转位以及IκBα和IκBβ的降解。结果：正常培养状态下，系膜细胞可组成型表达TNF—α和IL—1β，而不表达IL-1αmRNA，AngⅡ刺激后促炎性细胞因子表达显著上调，NF—κB特异性抑制剂2-硫代氨基甲酸吡咯烷显著抑制AngⅡ诱导的促炎性细胞因子基因表达；AngⅡ诱导系膜细胞NF—κB活化，p65核转位及胞质内IκBα和IκBα的降解。结论：AngⅡ诱导肾小球系膜细胞中促炎性细胞因子表达可能通过NF—κB／IκB信号转导通路来实现。     

雌、孕激素对子宫内膜癌细胞孤儿受体ERRα的调控作用

目的:探讨孤儿受体ERRα与雌激素(E)、孕激素(P)之间的相互关系及其在子宫内膜癌发病中的作用.方法:采用逆转录聚合酶链反应(RT-PCR)方法,检测不同浓度(10-10,10-8,10-6mol/L)17β-雌二醇(17β-E2)作用于Ishikawa细胞系不同时间(0 min,15 rmin,30 min和24 h)后ERRα mRNA的变化,并应用ER拮抗剂ICI182780同时作用细胞,观察是否可阻断E2对ERRα的调控作用;检测不同浓度孕酮(10-8,10-7,10-6,10-5mol/L)作用于Ishikawa细胞系24 h后ERRα mRNA的变化.结果:10-10mol/L 17β-E2作用于Ishikawa细胞系15 min,30 min及24 h后ERRα mRNA水平与未加E2相比均稍有增加,而10-8,10-6mol/L 17β-E2作用于细胞系15 min,30 min及24 h后ERRα mRNA明显减小,以10-8mol/L作用后减少最明显.同时加入E2和ICI182780作用于细胞系后,E2对ERRα mRNA的减小作用被阻断.10-8mol/L孕酮作用于细胞系24 h后,ERRα mRNA与对照组相比无明显变化,但加入10-7,10-6和10-5mol/L孕酮后,ERRα mRNA表达均出现明显增加.结论:17β-E2可减少子宫内膜癌细胞系Ishikawa细胞ERRα mRNA的表达,此减少作用是通过ER介导完成的.孕酮可增加ERRα mRNA的表达.     

罗格列酮对高糖刺激下肾小管上皮细胞凋亡及整合素β1表达的影响

目的 观察罗格列酮(ROS)对肾小管上皮细胞凋亡及整合素β1 (integrin β1)水平的影响.方法 将体外培养的大鼠近端肾小管上皮细胞分为空白对照组、正常血糖(5 mmol/L)组、高糖(30 mmol/L)组、ROS (10 μmol/L)组、高糖(30 mmol/L) ROS (5 μmol/L)组和高糖30 mmol/L ROS 10 μmol/L 6组, 采用流式细胞仪检测细胞培养后24、48、72 h的凋亡情况、Western blot及RT-PCR检测不同浓度的ROS对高糖刺激下integrin β1蛋白质和mRNA表达的影响.结果 integrin β1的蛋白质和mRNA的改变趋势相同,高糖组较对照组及正常血糖组增加(P＜0.05) ,经ROS处理后integrin β1的表达较高糖组降低,且与ROS浓度呈剂量相关.各实验组在48 h、72 h的细胞凋亡率与空白对照组相比均降低(P＜0.05);48、72 h的细胞凋亡率低于24 h(P＜0.05),但48 h与72 h间的比较差异无统计学意义.结论 ROS可明显抑制高糖刺激下肾小管上皮细胞integrin β1的表达,且有明显剂量依赖关系,而ROS对细胞凋亡的影响可能与 integrin β1的参与有关.     

mm—LDL对内皮细胞转录因子NF—kB活性的影响

目的 研究轻微修饰低密度脂蛋白（mm-LDL）激活内皮细胞转录因子NF－kB的信号传导途径以及NF－kB对血小板源性生长因子B链（PDGFb）表达的调控作用。方法 以FeSO4修饰法制备mm-LDL,以正常LDL（n-LDL）作对照,作用于培养内皮细胞后提取核蛋白,用凝胶阻滞实验检测转录因子NF－kB停车场 及结合活性的变化。观察自由基清除剂probucol及PDTC对mm-LDL激活内皮细胞转录因子NF－kB的影响。通过检测报告基因探讨核因子诱导激酶（NIK）和核因子－kB抑制亚基激酶（IKK）在激活内皮细胞转录因子NF－kB的信号传导途径中的作用以及mm-LDL激活的NF－kB对PDGFb基因启动子的作用。结果 mm-LDL能激活培养内皮细胞转录因子NF－kB,自由基清除剂probucol和PDTC对mm-LDL激活内皮细胞转录因子NF－kB还能增加带有PDGFb基因上游调控序列（－189／＋43)的报告基因荧光素酶的活性。Slot blot结果显示变异型NIK能显著减少受mm-LDL刺激的内皮细胞PDGFb mRNA含量。结论 mm-LDL可通过NIK－IKK途径激活内皮细胞转录因子NF－kB并促进PDGFb基因表达。