载脂蛋白嵌合模拟肽对巨噬细胞胆固醇流出的影响

目的观察载脂蛋白嵌合模拟肽Ac-hE-18A-NH2对RAW264.7巨噬细胞胆固醇流出的影响,并探讨其机制。方法 RAW264.7巨噬细胞种植于24孔板,用0.5μCi/孔3H-胆固醇和含50mg·mL-1氧化低密度脂蛋白共同孵育24h之后,给予不同浓度的Ac-hE-18A-NH2(0～100mg·mL-1)干预24h,收集细胞用液体闪烁计数法检测胆固醇流出。采用ELISA测定细胞内cAMP含量,采用实时荧光定量PCR及Westernblot检测ABCA1、LXRα和PPARγ的mRNA及蛋白表达。结果 Ac-hE-18A-NH2以浓度依赖方式介导胆固醇流出;50mg·mL-1Ac-hE-18A-NH2干预不同时间,其介导的胆固醇流出率分别为(10.86±1.46)%(6h),(13.43±1.55)%(12h),(20.58±1.34)%(18h),和(26.93±4.37)%(24h)。同时,Ac-hE-18A-NH2还以浓度依赖方式增加细胞内cAMP水平,上调ABCA1、LXRα和PPARγmR-NA和蛋白表达。加用cAMP刺激剂8-Br-cAMP,Ac-hE-18A-NH2介导的胆固醇流出率由26.93±4.37增加至35.81±2.73,ABCA1mRNA表达增加了66.67%。而加用PPARγ特异性抑制剂预处理细胞后,PPARγ的表达几乎完全抑制,ABCA1和LXRα的表达也受到一定程度抑制,Ac-hE-18A-NH2介导的胆固醇流出率明显减少。结论模拟肽Ac-hE-18A-NH2可以明显促进巨噬细胞胆固醇流出,其机制可能与cAMP-ABCA1和PPARγ-LXRα-ABCA1两种途径有关。     

尼曼-匹克C1型类似蛋白1介导依泽替米贝对RAW264.7细胞脂质蓄积的抑制作用

目的观察肠道胆固醇吸收抑制剂依泽替米贝(ezetimibe)对RAW264.7细胞源性荷脂细胞脂质蓄积的影响并对其机制进行初步探讨。方法采用油红O染色、高效液相色谱法检测细胞内脂滴数量和细胞内脂质含量,Western blot对NPC1L1(Niemann-Pick type C1Like-1)进行定性和半定量检测。结果RAW264.7细胞中有NPC1L1蛋白表达。不同浓度(0、0.003、0.01和0.03mol.L-1)依泽替米贝预先孵育RAW264.7细胞24h或最佳浓度(0.03mol.L-1)预先孵育不同时间(0、6、12和24h)后,换50mg.L-1oxLDL继续孵育24h,结果显示不同浓度ezetimibe预先孵育后,细胞内脂滴数量与面积随着浓度的增加而逐渐减少;Ezetimibe预先孵育可减少细胞内脂质蓄积,并呈浓度和时间依赖性。其中0.03mol.L-1ezetimibe预先孵育24h组作用最明显,CE百分比较oxLDL单独孵育组减少了约47%±0.1%。结论小鼠源性巨噬细胞RAW264.7中存在NPC1L1蛋白表达;依泽替米贝能够减少RAW264.7细胞中NPC1L1蛋白表达;依泽替米贝抑制RAW264.7细胞中脂质蓄积。     

PPARγ激动剂对RAW264.7巨噬细胞源性泡沫细胞胆固醇流出的影响

目的观察PPARγ激动剂吡格列酮对RAW264.7巨噬细胞源性泡沫细胞胆固醇流出调节蛋白三磷酸腺苷结合核转运蛋白G1(ABCG1)、肝X受体α(LXRα)表达的影响。方法 (1)体外培养RAW 264.7巨噬细胞,用50 mg/L的氧化型低密度脂蛋白胆固醇(ox-LDL)孵育48 h诱导成泡沫细胞,油红O染色并在光镜下鉴定泡沫细胞形态及变化。(2)以不同浓度吡格列酮(0、5、10、20、30μmol/L)作用泡沫细胞24 h后,酶法检测泡沫细胞内胆固醇酯的含量。用反转录-聚合酶链反应(RT-PCR)及免疫印迹法测定ABCG1、LXRα的mRNA及蛋白的表达。结果 PPARγ激动剂吡格列酮可显著减少泡沫细胞内胆固醇酯含量,并呈浓度依赖性增加RAW264.7巨噬细胞源性泡沫细胞ABCG1、LXRα的mRNA和蛋白的表达。结论 PPARγ激动剂吡格列酮减少泡沫细胞内胆固醇酯的含量可能是通过上ABCG1、LXRα的mRNA及蛋白表达来实现的。     

脂联素对巨噬细胞源性泡沫细胞ABCA1及胆固醇含量的影响及机制

目的探讨脂联素对RAW264.7巨噬细胞源性泡沫细胞ABCA1及胆固醇含量的影响及其可能的机制。方法体外培养RAW264.7细胞,加入20 mg/L氧化低密度脂蛋白(ox-LDL)共同孵育48 h,将其诱导成泡沫细胞,加入不同浓度(0、1、5、10μg/mL)的脂联素干预24 h,RT-PCR测定ABCA1 mRNA的表达,高效液相色谱测定细胞内胆固醇含量。观察脂联素对泡沫细胞中ABCA1表达的影响。结果脂联素显著增加RAW264.7巨噬细胞源性泡沫细胞ABCA1 mRNA的表达(P<0.05),并增加细胞内胆固醇含量,且呈浓度依赖性(P<0.05)。结论脂联素可以增加巨噬源性泡沫细胞ABCA1转录水平,促进胆固醇流出,延缓AS的发生发展。     

五味子甲素对脂多糖诱导的小鼠RAW264.7细胞的抗炎作用

目的：探讨五味子甲素对脂多糖诱导的小鼠RAW264.7细胞的抗炎作用。方法：检测五味子甲素对于脂多糖诱导的RAW264.7细胞的增殖、凋亡、吞噬及细胞内白细胞介素-lβ（IL-lβ）、肿瘤坏死因子-α（TNF-α）、前列腺素E2（PGE2）和环氧合酶-2（COX-2）水平的影响。脂多糖诱导后加入不同浓度五味子甲素,CCK8法测定RAW264.7细胞增殖,中性红试剂检测诱导后RAW264.7细胞的吞噬能力。经酶联免疫吸附试验（ELISA）法测定细胞培养血清中IL-lβ、TNF-α、PGE2和COX-2水平的表达。Annexin V-FITC/PI双染检测五味子甲素对诱导后RAW264.7细胞凋亡的影响。结果：五味子甲素可明显抑制脂多糖诱导的RAW264.7细胞的增殖、吞噬能力及诱导刺激的细胞凋亡;ELISA结果显示,五味子甲素可以抑制细胞IL-lβ、TNF-α、PGE2和COX-2的水平。结论：五味子甲素对脂多糖诱导的小鼠RAW264.7细胞炎症具有明显的抑制作用,其机制可能与抑制炎症细胞的增殖、吞噬,减少炎症因子释放,减轻脂多糖诱导引起的细胞凋亡有关。     

八肽胆囊收缩素通过p38MAPK通路抑制LPS诱导的RAW264.7细胞IL-1β表达

目的研究八肽胆囊收缩素(CCK-8)对LPS诱导RAW264.7细胞IL-1β表达的影响及相关机制。方法用ELISA及RT-PCR法检测RAW264.7细胞IL-1βmRNA及蛋白表达;用Western blot检测RAW264.7细胞p38 MAPK的磷酸化水平。结果①LPS可时间依赖性的诱导RAW264.7细胞IL-1βmRNA及蛋白的表达,分别于刺激后3 h及6 h达到高峰;②10-10 mol.L-1 CCK-8对LPS诱导的RAW264.7细胞IL-1β表达无影响;10-8、10-6 mol.L-1CCK-8浓度依赖性地抑制了LPS诱导的RAW264.7细胞IL-1β表达;③10-10 mol.L-1 CCK-8未影响LPS诱导的p-p38MAPK水平,10-8、10-6 mol.L-1 CCK-8浓度依赖性地抑制了LPS诱导的p-p38 MAPK水平;④p38 MAPK特异性抑制剂SB203580可抑制LPS诱导的RAW264.7细胞IL-1β表达,与CCK-8共同作用后,抑制作用进一步加强。结论 CCK-8通过抑制p38 MAPK磷酸化而抑制了LPS诱导的RAW264.7细胞IL-1β表达,这可能是CCK-8发挥抗炎作用的信号转导机制之一。     

香青兰总黄酮对RAW264.7巨噬细胞泡沫化及炎症反应的调控作用北大核心CSCD

目的研究香青兰总黄酮(total flavonoids of Dracocephalum moldavica L.,TFDM)对氧化低密度脂蛋白(oxidized low density lipoprotein,ox-LDL)诱导的小鼠单核巨噬细胞白血病细胞(RAW264.7)泡沫化及炎症的影响,进一步阐明TFDM抗动脉粥样硬化(atherosclerosis,AS)的作用机制。方法体外培养RAW264.7巨噬细胞,采用ox-LDL刺激诱导使其成为泡沫细胞,TFDM(25、50、100 mg·L^(-1))及辛伐他汀(10μmol·L^(-1))进行干预,油红O染色法观察胞内脂滴的聚集情况,CCK-8法检测细胞活力,活性氧试剂盒测定ROS的生成,实时荧光定量PCR测定细胞中NF-κB、NLRP3、caspase-1、IL-18和IL-1βmRNA的表达,免疫蛋白印迹法检测巨噬细胞中IκBα、NF-κB p65、NLRP3、pro-caspase-1、caspase-1、IL-1β以及IL-18蛋白的表达,ELISA法检测TNF-α和IL-10的表达。结果TFDM可以减少泡沫巨噬细胞的形成,降低炎症因子IL-1β、IL-18和TNF-α的表达,增加抑炎因子IL-10的表达;并且下调NF-κB p65、NLRP3、pro-caspase-1、caspase-1蛋白的表达,上调IκBα的蛋白表达。结论TFDM能够减轻巨噬细胞的泡沫化,抑制炎症因子的表达,从而可能延缓动脉粥样硬化的发展进程。其作用机制可能是通过抑制NF-κB途径,减少ox-LDL诱导的RAW264.7细胞中炎症介质的产生。     

线粒体复合体Ⅲ抑制剂抗霉素A对巨噬细胞免疫功能的影响

目的研究线粒体复合体Ⅲ抑制剂抗霉素A(AMA)对巨噬细胞免疫功能的影响,并探讨其可能的作用机制。方法 AMA 0.0005,0.05,0.5,5和10 mg·L-1与RAW264.7巨噬细胞分别作用2,24和48 h后,WST-1法检测巨噬细胞增殖;AMA 0.0005,0.05和0.5 mg·L-1与RAW264.7作用2 h后,定量荧光法检测巨噬细胞产生活性氧水平、线粒体膜电位和对白色念珠菌的吞噬作用;Western蛋白印迹法检测丝裂原活化蛋白激酶(MAPK)P38蛋白磷酸化水平;Griess法检测细胞培养上清一氧化氮含量。结果 AMA作用2 h对RAW264.7巨噬细胞增殖无明显影响,当作用时间延长到24和48 h后,可显著抑制RAW264.7巨噬细胞增殖(P<0.01)。AMA作用2 h可显著诱导RAW264.7巨噬细胞产生活性氧(P<0.01),降低线粒体膜电位(P<0.01)。AMA可增强RAW264.7巨噬细胞对白色念珠菌的吞噬功能,显著降低脂多糖诱导的巨噬细胞炎症介质一氧化氮的产生(P<0.01)。AMA显著诱导MAPK P38磷酸化(P<0.01)。结论 AMA能够诱导RAW264.7巨噬细胞线粒体损伤,增强巨噬细胞对白色念珠菌的吞噬功用,降低脂多糖诱导的炎症反应,可能与激活MAPK P38磷酸化,进而激活MAPK信号转导通路有关。     

微囊藻毒素-LR对小鼠巨噬细胞吞噬功能及活性氧水平的影响

目的观察微囊藻毒素LR(MC-LR)对原代和传代巨噬细胞功能的影响。方法取BALB/c小鼠腹腔巨噬细胞,体外培养液中分别加入终浓度为1,10,100和1000nmol.L-1的MC-LR,同时以巨噬细胞株RAW264.7为对照,分别采用中性红吞噬实验和二氢罗丹明123探针检测实验,测定细胞吞噬活性和细胞内活性氧(ROS)水平。结果MC-LR对小鼠腹腔巨噬细胞的吞噬功能有浓度依赖的抑制作用。当MC-LR浓度高于10nmol.L-1时,小鼠腹腔巨噬细胞的胞内ROS水平也明显降低。但MC-LR对小鼠巨噬细胞系RAW264.7细胞的吞噬功能和细胞内ROS水平均无明显影响。结论MC-LR可抑制小鼠腹腔巨噬细胞的吞噬功能和ROS水平,原代巨噬细胞对MC-LR的敏感性高于传代细胞RAW264.7。     

染料木素通过TIPE 2负性调控Akt活性促进脂多糖活化的巨噬细胞凋亡

目的探究染料木素(genistein,GEN)对脂多糖(lipopolysaccharide,LPS)活化的RAW264.7细胞凋亡的影响及其可能的药理学作用机制。方法GEN预孵育RAW264.7细胞或慢病毒介导的肿瘤坏死因子α诱导蛋白8样分子2(tumor necrosis factor-α-induced protein 8-like 2,TIPE 2)过表达细胞2 h,再与LPS共孵育24 h,采用CCK 8试剂盒检测细胞活力,Annexin V-FITC/PI试剂盒检测细胞凋亡水平,qRT-PCR检测TNF-α、IL-6、caspase-8、caspase-3和TIPE 2 mRNA,Western blot检测iNOS、COX-2、caspase-8、caspase-3、TIPE 2、Akt和p-Akt蛋白表达。结果LPS促进RAW264.7细胞TNF-α、IL-6、iNOS、COX-2合成;GEN抑制LPS活化的RAW264.7细胞活力,凋亡细胞增多,并上调caspase-8、caspase-3、TIPE 2 mRNA及蛋白表达;TIPE 2过表达上调活化RAW264.7细胞caspase-8、caspase-3 mRNA及蛋白表达,减少Akt磷酸化,且与GEN具有协同作用。结论GEN可能通过上调TIPE 2抑制Akt活性,激活外源性凋亡途径,促进LPS活化的RAW264.7细胞凋亡。     

Berberine-induced inhibition of adipocyte enhancer-binding protein 1 attenuates oxidized low-density lipoprotein accumulation and foam cell formation in phorbol 12-myristate 13-acetate-induced macrophages

The phagocytosis of oxidized low-density lipoprotein (oxLDL) by monocyte-derived macrophages and the subsequent differentiation of macrophages into foam cells are the key steps in atherogenesis. Scavenger receptors, such as CD36 and lectin-like low-density lipoprotein receptor 1 (LOX-1), are responsible for the uptake of oxLDL. Adipocyte enhancer-binding protein 1 (AEBP1) regulates many key genes associated with intracellular cholesterol efflux. The present study investigated the function of berberine, a compound isolated from Rhizoma coptidis, on foam cell formation, and explored the possible underlying mechanism. We found that berberine inhibited the oxLDL uptake of macrophages and reduced foam cell formation in a dose-dependent manner. Moreover, AEBP1 expression in macrophages increased and decreased after oxLDL and berberine treatments in a dose-dependent manner, respectively. Berberine reduced the expression of scavenger receptors CD36 and LOX-1, but did not affect the expression of CD68 in oxLDL-stimulated macrophages. Overall, berberine reduced foam cell formation by a dual mechanism, which decreased oxLDL internalization via the suppression of CD36 and LOX-1, and increased cholesterol efflux by inhibiting AEBP1 expression in macrophages.     

Hibiscus anthocyanins-rich extract inhibited LDL oxidation and oxLDL-mediated macrophages apoptosis.

The oxidative modification of low-density lipoprotein (LDL) plays a key role in the pathogenesis of atherosclerosis. Anti-oxidative reagents, which can effectively inhibit LDL oxidation, may prevent atherosclerosis via reducing early atherogenesis, and slowing down the progression to advance stages. As shown in previous studies Hibiscus sabdariffa L. is a natural plant containing a lot of pigments that was found to possess anti-oxidative of activity. Therefore, in this study, we evaluated the anti-oxidative activity of Hibiscus anthocyanins (HAs) by measuring their effects on LDL oxidation (in cell-free system) and anti-apoptotic abilities (in RAW264.7 cells). HAs have been tested in vitro examining their relative electrophoretic mobility (REM), Apo B fragmentation, thiobarbituric acid relative substances (TBARS) and radical 1,1-diphenyl-2-picrylhydrazyl (DPPH) scavenging activity assay. The anti-oxidative activity of HAs was defined by relative electrophoretic mobility of oxLDL (decrease of 50% at 2 mg/ml), fragmentation of Apo B (inhibition of 61% at 1mg/ml), and TBARS assay (IC(50): 0.46 mg/ml) in the Cu(2+)-mediated oxidize LDL. Furthermore, the addition of >0.1 mg/ml of HAs could scavenge over 95% of free DPPH radicals, HAs showed strong potential in inhibiting LDL oxidation induced by copper. In addition, to determine whether oxLDL-induced apoptosis in macrophages is inhibited by HAs, we studied the viability, morphology and caspase-3 expression of RAW 264.7 cells. MTT assay, Leukostate staining analysis and Western blotting reveals that HAs could inhibit oxLDL-induced apoptosis. According to these findings, we suggest that HAs may be used to inhibit LDL oxidation and oxLDL-mediated macrophage apoptosis, serving as a chemopreventive agent. However, further investigations into the specificity and mechanism(s) of HAs are needed.     

Involvement of phospholipase A2 in the supply of fatty acids required for cholesterol esterification associated with uptake of oxidized low-density lipoprotein in macrophages

The formation of foam cells, a critical event in the early stages of atherosclerosis, is associated with the uptake of oxidized low-density lipoprotein (oxLDL) by macrophages and the subsequent accumulation of cholesterol ester formed by the catalytic action of acyl-CoA: cholesterol acyltransferase (ACAT). Although free cholesterol, a substrate for ACAT, is supplied from the intracellular cholesterol pool, little is known about the pathways involved in the supply of fatty acids, precursors for fatty acyl-CoA as another substrate for ACAT. Our recent studies were undertaken to examine the possible involvement of phospholipase A2 (PLA2) in the supply of fatty acids required for the cholesterol esterification. In mouse peritoneal macrophages and RAW264.7 macrophages, oxLDL induced the liberation of fatty acids from membrane phospholipids to increase cholesterol ester having the fatty acids as an acyl chain. The changes in these lipids were suppressed by the inhibition of cytosolic PLA2 (cPLA2). Although oxLDL did not affect the activity or amounts of cPLA2, preincubation with oxLDL enhanced the release of fatty acids induced by Ca2+ ionophore, which accelerates the hydrolytic action of cPLA2. We further observed that oxLDL induced the generation of ceramide through the de novo synthesis. Exogenous ceramide and 13-hydroxyoctadecadienoic acid, an oxidized lipid in oxLDL particles, also stimulated fatty acid release. Based on these findings, we propose that oxLDL activates cPLA2 to supply fatty acids required for the cholesterol esterification, through the acceleration of the hydrolytic action of cPLA2 by endogenous ceramide and by oxidized lipids in oxLDL particles in macrophages.     

Varenicline aggravates atherosclerotic plaque formation in nicotine-pretreated ApoE knockout mice due to enhanced oxLDL uptake by macrophages through downregulation of ABCA1 and ABCG1 expression

Varenicline is a widely used and effective drug for smoking cessation. We previously reported that varenicline aggravates atherosclerosis in apolipoprotein E knockout (ApoE KO) mice. However, it remains unknown whether varenicline affects cardiovascular events in patients with nicotine addiction. Here, we examined the effect of varenicline on atherosclerotic plaque formation in nicotine-pretreated ApoE KO mice and oxidized low-density lipoprotein (oxLDL) uptake in nicotine-treated peritoneal macrophages. Varenicline caused significant progression of plaque formation in the whole aorta and aortic root and further accelerated the increased formation of a macrophage-rich plaque area in the aortic root in nicotine-pretreated ApoE KO mice. Varenicline (10 μM) enhanced oxLDL uptake in peritoneal macrophages. Furthermore, this treatment significantly further lowered the decreased protein levels of ATP-binding cassette (ABC) transporter without affecting the expression of scavenger receptors LOX-1 and CD36 in RAW264.7 cells treated with 100 nM nicotine. Varenicline enhanced nicotine-induced oxLDL uptake in macrophages through decreased expression of cholesterol efflux transporters ABCA1 and ABCG1 and thereby progressed atherosclerotic plaque formation. Taken together, we tentatively conclude that nicotine exposure before and/or during varenicline treatment can aggravate varenicline-increased atherosclerotic plaque formation and progression. Therefore, this enhanced risk requires special consideration when prescribing varenicline to smoker patients.     

八肽胆囊收缩素抑制LPS诱导的RAW264.7细胞AP-1活性及IL-6表达

目的研究八肽胆囊收缩素(CCK-8)对LPS诱导RAW264.7细胞IL-6表达的影响及相关机制。方法用ELISA及RT-PCR法检测RAW264.7细胞IL-6蛋白及mR-NA表达;用EMSA方法检测RAW264.7细胞AP-1 DNA结合活性。结果①LPS可时间依赖性的诱导RAW264.7细胞IL-6蛋白及mRNA表达;②10-10 mol.L-1 CCK-8对LPS诱导的RAW264.7细胞IL-6表达无明显影响;10-8、10-6 mol.L-1 CCK-8浓度依赖性地抑制了LPS诱导的RAW264.7细胞IL-6表达;③10-10 mol.L-1 CCK-8未影响LPS诱导的AP-1活性,10-8、10-6 mol.L-1 CCK-8浓度依赖性地抑制了LPS诱导的AP-1活性。结论 CCK-8通过抑制AP-1 DNA结合活性而抑制了LPS诱导的RAW264.7细胞IL-6表达,这可能是CCK-8发挥抗炎作用的信号转导机制之一。