莲心碱通过抑制NF-κB激活Nrf2/HO-1通路发挥抗炎抗氧化作用

目的 探讨莲心碱(liensinine, lie)在脂多糖(lipid polysaccharides, lPS)诱导的RAW264.7细胞炎症模型中的抗炎抗氧化作用机制。方法 将细胞分为对照组(Control group),LPS组(LPS group),莲心碱(0.5、1、2μmol/L)组。采用CCK-8法筛选莲心碱的无细胞毒性浓度,Griess法检测一氧化氮(NO)的浓度,酶联免疫法(ELISA)检测前列腺素2(PGE2)的浓度以及促炎因子(TNF-α、IL-6和IL-1β)的含量、实时荧光定量PCR(qRT-PCR)检测COX-2和iNOS mRNA的表达,DCFH-DA探针检测细胞中活性氧(ROS)含量,试剂盒检测细胞中超氧化物歧化酶(SOD)的活性以及谷胱甘肽(GSH)和丙二醛(MDA)的含量,蛋白质免疫印迹法(Western Blot)检测NF-κB、MAPK和Nrf2/HO-1通路中关键蛋白的表达情况。结果 0～4μmol/L莲心碱对细胞活力无影响,与LPS组相比,莲心碱组(0.5、1、2μmol/L)细胞中的促炎因子含量下降(P<0.05),NO和PGE2浓度...     

EGCG通过STAT3抑制血管内皮细胞炎性因子表达

[目的]研究茶多酚EGCG对脂多糖(LPS)诱导的血管内皮细胞炎性因子表达的抑制作用及其机制。[方法]利用MTT和流式检测LPS和EGCG对血管内皮细胞的毒性作用,实时荧光定量PCR检测炎性因子mRNA的水平,多重液相蛋白定量技术检测炎性因子的蛋白表达,Western Blot检测STAT3及其磷酸化水平。[结果]EGCG最大浓度(100μmol/L)对血管内皮细胞无毒性;LPS处理可显著或极显著诱导炎性因子(TNF-α、IL-1β、IL-6和IL-8)在mRNA和蛋白水平的表达(P<0.05或P<0.01),LPS对炎性因子的促进作用具有剂量效应;25μmol/L或50μmol/L EGCG预处理能极显著抑制LPS诱导的血管内皮细胞炎性因子的表达(P<0.01),同时抑制LPS诱导的STAT3磷酸化;STAT3抑制剂能显著增强EGCG抗炎效果。[结论]EGCG通过STAT3通路抑制LPS诱导的血管内皮细胞炎症因子的表达。     

蒲公英三萜类物质的抗炎作用研究进展

蒲公英三萜类物质是传统药用植物蒲公英中一类成分,包括蒲公英甾醇、蒲公英赛醇等。研究表明蒲公英三萜类物质具有良好的抗炎作用,除对多种炎症模型都有明确的防治作用外,还可抑制LPS诱导的炎症相关诱导酶类的合成以及多种炎症介质的释放。在抗炎的分子机制方面,蒲公英三萜类物质可显著抑制脂多糖(LPS)诱导的MAPKs通路和NF-κB通路的激活。综上表明蒲公英三萜类物质是蒲公英抗炎的重要成分。     

天麻素抑制脂多糖诱导的BV-2小胶质细胞炎症反应及机制研究

目的:研究天麻素对脂多糖(LPS)诱导的小胶质细胞炎性反应的影响,并探讨其潜在的作用机制。方法:BV-2小胶质细胞分为对照组、LPS组和天麻素组。LPS和天麻素处理24 h后,MTT和LDH试验检测细胞活性。ELISA实验检测炎性因子白介素-1β(IL-1β)、白介素-6(IL-6)和肿瘤坏死因子-α(TNF-α)的含量。Western blot检测细胞中Iba-1和TLR4的表达,以及IκBα的降解和NFκB-P65的核转位情况。结果:LPS刺激后,BV-2细胞活性下降(65.46±3.70%),LDH释放量增加(264.54±17.78 U/L),各炎性因子水平也显著升高。给予天麻素处理后,细胞活性升高(74.33±4.22%),LDH释放量减少(173.88±15.23 U/L),炎性反应降低。同时,天麻素显著抑制LPS诱导的BV-2细胞Iba-1升高,降低了LPS处理后细胞TLR4的升高,IκBα的磷酸化水平和P65的核转位。结论:天麻素可以提高BV-2细胞活性,缓解LPS诱导的炎症反应。其作用机制可能是通过抑制BV-2细胞的过度活化,调控TLR4/NFκB信号通路,最终减少炎症因子的表达。     

适宜浓度短链脂肪酸混合物对小胶质细胞炎症 抑制及机制研究

本研究的主要目的是探讨适宜浓度短链脂肪酸(short chain fatty acids,SCFAs)混合物对炎症环境下小胶质细胞的抑炎作用及其机制.采用脂多糖(LPS)刺激小鼠小胶质细胞系BV-2细胞建立神经炎症模型,并利用CCK8试剂盒检测不同浓度单一的乙酸钠、丙酸钠、丁酸钠处理后的细胞活力.设计选取这三种SCFAs对细胞活力无影响、且有抑炎效果的特定浓度进行组合(SCFAs mix),进一步检测SCFAs mix对LPS刺激下BV-2细胞炎症反应的影响及机制,包括:a.用一氧化氮(NO)试剂盒检测NO的释放;b.用ELISA检测炎症因子TNF-α、IL-6的释放;c.用qRT-PCR和Western blot检测炎症因子TNF-α、IL-6、炎症小体NLRP3、炎症通路相关蛋白TLR4、NF-κB等的表达变化.结果表明LPS刺激BV-2细胞4 h后,在体系中添加特定浓度的单一SCFA处理12 h后,不能缓解BV-2细胞的炎症反应,而将上述SCFAs配制成同等终浓度的SCFAs mix处理12 h却能显著降低细胞培养上清液中NO、TNF-α和IL-6 (均P0.001)的量,还能抑制BV-2细胞内iNOS、TNF-α、IL-6和NLRP3 mRNA的升高(均P0.001);通过对炎症信号通路关键分子的检测发现,SCFAs mix可以抑制LPS诱导的BV-2细胞内TLR4、MyD88、TRAF6和NF-κB蛋白的表达升高.综上可见:适宜浓度的混合SCFAs可通过调控TLR4/MyD88/TRAF6/NF-κB炎症通路抑制LPS诱导的小胶质细胞的炎症反应,而起到抗炎的保护作用.     

连翘脂素对LPS诱导RAW264.7细胞炎症反应的影响

为研究连翘脂素的抗炎效应及其抗炎机制,以地塞米松作为阳性对照,建立脂多糖(LPS)诱导小鼠巨噬细胞RAW264.7炎症模型,检测炎症因子的释放及相关蛋白和mRNA的表达,以期提高对连翘脂素抗炎作用的全面认识并为连翘脂素临床开发提供有力的科学依据。实验采用Griess法检测细胞上清液中NO含量,ELISA法检测TNF-α和IL-6的含量,Westernblot法检测iNOS、COX-2蛋白的表达,RT-qPCR法检测iNOS、COX-2mRNA的表达。与LPS组比较,连翘脂素组和地塞米松组可以明显降低LPS诱导的RAW264.7细胞释放NO、TNF-α和IL-6的量,并呈现浓度依赖关系。Westrenblot和RT-qPCR结果显示连翘脂素能抑制LPS诱导的iNOS、COX-2的蛋白表达以及mRNA的表达,并呈浓度依赖关系。实验研究表明连翘脂素能够明显抑制LPS诱导的RAW264.7细胞炎症因子的释放,iNOS、COX-2蛋白及mRNA的表达从而抑制炎症反应。     

综述:炎症小体信号通路的负调控

炎症小体(inflammasomes)活化后产生的IL-1β和IL-18等促炎因子对天然免疫和适应性免疫具有重要作用.炎症小体持续活化可引起促炎因子过度表达,导致慢性炎症和自身免疫疾病的发生.正常生理状态下,机体存在多种炎症小体负调机制,以维持免疫反应平衡.病理状态下,感染机体的病原微生物通过多种途径抑制炎症小体信号通路的活化及促炎因子的产生,以利于免疫逃逸.本文综述了机体和病原微生物对炎症小体信号通路的负调控机理.阐明炎症小体信号通路负调控机制将为感染性疾病及其他炎症小体相关炎症性疾病的治疗提供策略.     

基于PI3K/AKT/mTOR通路的三百棒促进脂多糖诱导的RAW 264.7细胞自噬并抑制炎症CSCD

三百棒来源于芸香科植物飞龙掌血Toddalia asiatica(L.)Lam的根,是一种天然土家族中草药,具有抗炎、抗风湿、抗肿瘤、抗微生物等药理活性。其毒副作用小,疗效显著的特点使之成为当前研究热点。许多天然产物已被证明可通过靶向PI3K/AKT/mTOR介导的自噬来抑制炎症及自身免疫性疾病,本项研究通过调节PI3K/AKT/mTOR信号通路来研究三百棒醇提物(Toddalia asiatica alcohol extract,TAAE)对自噬的影响,用脂多糖(LPS)诱导单核巨噬细胞(RAW 264.7)建立炎症模型,通过细胞毒性检测试剂盒检测TAAE对细胞活力的影响,并筛选出药物的浓度及干预时间,透射电镜和单丹磺酰尸胺染色检测巨噬细胞的生物学功能,酶联免疫吸附法检测上清液中相关炎症因子水平,Western blot检测自噬和通路相关蛋白的表达水平;并采用自噬早期抑制剂(3-MA)和通路PI3K激动剂(740Y-P)进一步验证自噬对炎症和信号通路的影响。实验结果表明TAAE可能通过抑制PI3K/AKT/mTOR信号通路,促进自噬泡的形成、自噬体溶酶体融合和降解,降低LPS处理的RAW 264.7细胞中炎性细胞因子的表达和分泌。总体而言,本研究结果为三百棒的抗炎机制的研究提供了新的线索,并为临床更好的应用三百棒治疗炎症性疾病提供理论依据。     

FABP4对脂多糖诱导Kupffer细胞NF-κB活化和炎症的影响

目的:研究脂肪型脂肪酸结合蛋白(FABP4)对脂多糖(LPS)诱导Kupffer细胞(KCs)NF-κB通路活化和炎症反应的影响。方法:通过梯度离心的方法分离大鼠KCs,按照1×10~5接种于6孔板,贴壁后饥饿24 h,不同浓度脂多糖(LPS,0、5、10和20ng/mL)刺激24 h,提取蛋白和RNA,通过Western-Blot检测NF-κB通路蛋白表达变化,利用荧光定量PCR检测IL-1β和IL-6m RNA表达变化;利用RNAi沉默KCs FABP4表达,通过Western-Blot和荧光定量PCR检测其对LPS诱导NF-κB通路活化的影响;分别利用FABP4细胞因子刺激和慢病毒上调FABP4的表达,通过Western-Blot和荧光定量PCR检测其对KCs NF-κB通路和炎症反应的影响。结果:LPS能够以浓度依赖的方式(0、5、10和20 ng/m L)诱导KCs FABP4 m RNA和蛋白的表达,以20 ng/mL最为明显(P0.05);沉默FABP4可以显著减弱LPS(20 ng/m L)诱导的p-p65和p-IκBα的表达,以及炎症细胞因子IL-1β和IL-6的释放(P0.05);外源性FABP4(10 ng/mL和20 ng/m L)刺激24h后,能够明显诱导p-p65和p-IκBα的表达,促进炎症因子(IL-1β和IL-6)的合成(P0.05);利用慢病毒上调FABP4,可以显著诱导p-p65和p-IκBα的表达以及炎症因子(IL-1β和IL-6)的表达(P0.05),而抗氧化剂NAC(10μM)处理,则显著减弱此效应(P0.05)。结论:FABP4介导了LPS刺激KCs NF-κB通路的活化和炎症反应。     

荷叶碱对脂多糖诱导的大鼠软骨细胞炎症的抗炎作用研究

目的探讨荷叶碱对软骨细胞的保护作用及对软骨细胞炎症的抗炎作用。方法取体外分离培养3~5天的SD大鼠膝关节软骨细胞,应用10μg/ml LPS诱导软骨细胞建立体外骨关节炎模型。将实验分为3组,即空白组、模型组(LPS)和实验组(LPS+荷叶碱)。通过活/死细胞(Calcein-AM/EthD-I)双染色,实时荧光定量聚合酶链反应(qRT-PCR),HE染色(苏木素-伊红),番红O染色,免疫荧光染色,检测荷叶碱抑制软骨细胞外基质降解作用及缓解软骨细胞炎症的作用。结果荷叶碱浓度为10μM时,无明显毒性,Calcein-AM/EthD-I染色表明该浓度对炎症诱导的软骨细胞有保护作用。qRT-PCR表明,与模型组相比,实验组的Col2al表达升高,MMP-13和IL-6表达下降。HE染色(苏木素-伊红)、番红O染色、免疫荧光染色结果表明荷叶碱能够维持软骨细胞的形态,促进软骨细胞蛋白多糖的分泌,抑制MMP-13的表达。结论浓度为10μM的荷叶碱对LPS诱导的软骨细胞有较好保护作用及抗炎作用,无毒副作用。     

Lycorine: a eukaryotic termination inhibitor?

The effect of the alkaloid lycorine on viral protein synthesis was studied in poliovirus-infected HeLa cells. The incorporation of [3H]leucine was inhibited by lycorine in a dose-dependent way, although lycorine never completely abolished translation. Using polyacrylamide gel electrophoresis, the viral proteins were identified as derived from the P1 (5' terminal), P2 (middle), or P3 (3' terminal) region of the poliovirus translation unit. The residual labeling of viral proteins in the presence of lycorine was mainly due to synthesis of P1 proteins and slightly less to P2 proteins, while virtually no P3-derived proteins were made. It is suggested that lycorine may act at the level of termination.     

Various sensitivities of yeasts to lycorine

Lycorine, an Amaryllidaceae alkaloid, is a powerful inhibitor of growth in higher plants and algae. Thirty-one strains of yeasts, belonging to different genera and species, were screened to study the effect of lycorine on their growth. The strains were incubated at 25 degrees C in a 2% glucose medium with different concentrations of lycorine (10, 50 and 100 microM), and their growth after 72 hours was evaluated. Most of the strains showed no sensitivity to lycorine. However, in Schizosaccharomyces pombe (IMAT-V Pbx) and Aureobasidium pullulans (DBV A77) lycorine significantly inhibited growth (59-73%), while, on the contrary, in Saccharomycopsis fibuligera (DBV 3812) and Cryptococcus terreus (CBS 1895) it was clearly stimulated (76-140%). The fact that lycorine inhibits growth in some yeasts while it stimulates it in others means that neither of the two previously formulated interpretations on the molecular mechanism of action of alkaloid can explain all cases. In other words, it does not seem that lycorine just inhibits protein synthesis, as claimed by Kukhanova et al. (1983), nor, on the other hand, do the data presented here prove that lycorine specifically inhibits ascorbic acid biosynthesis (Arrigoni et al., 1975). We must now check the ability of yeasts to split lycorine and study whether yeasts do actually have an ascorbic acid system.     

Lycorine,a non-nucleoside RNA dependent RNA polymerase inhibitor,as potential treatment for emerging coronavirus infections

Background: Highly effective novel treatments need to be developed to suppress emerging coronavirus (CoV) infections such as COVID-19. The RNA dependent RNA polymerase (RdRp) among the viral proteins is known as an effective antiviral target. Lycorine is a phenanthridine Amaryllidaceae alkaloid isolated from the bulbs of Lycoris radiata (L'Hér.) Herb. and has various pharmacological bioactivities including antiviral function.Purpose: We investigated the direct-inhibiting action of lycorine on CoV's RdRp, as potential treatment for emerging CoV infections.Methods: We examined the inhibitory effect of lycorine on MERS-CoV, SARS-CoV, and SARS-CoV-2 infections, and then quantitatively measured the inhibitory effect of lycorine on MERS-CoV RdRp activity using a cell-based reporter assay. Finally, we performed the docking simulation with lycorine and SARS-CoV-2 RdRp.Results: Lycorine efficiently inhibited these CoVs with IC₅₀ values of 2.123 ± 0.053, 1.021 ± 0.025, and 0.878 ± 0.022 μM, respectively, comparable with anti-CoV effects of remdesivir. Lycorine directly inhibited MERS-CoV RdRp activity with an IC₅₀ of 1.406 ± 0.260 μM, compared with remdesivir's IC₅₀ value of 6.335 ± 0.731 μM. In addition, docking simulation showed that lycorine interacts with SARS-CoV-2 RdRp at the Asp623, Asn691, and Ser759 residues through hydrogen bonding, at which the binding affinities of lycorine (−6.2 kcal/mol) were higher than those of remdesivir (−4.7 kcal/mol).Conclusions: Lycorine is a potent non-nucleoside direct-acting antiviral against emerging coronavirus infections and acts by inhibiting viral RdRp activity; therefore, lycorine may be a candidate against the current COVID-19 pandemic.     

Lycorine inhibits breast cancer growth and metastasis via inducing apoptosis and blocking Src/FAK-involved pathway

Breast cancer is the most commonly diagnosed cancer type worldwide among women and more than 90% of patients die from tumor metastasis. Lycorine, a natural alkaloid, has been widely reported possessing potential efficacy against cancer proliferation and metastasis. In our study, the anti-tumor potency on breast cancer was evaluated in vitro and in vivo for the first time. Our results indicated that lycorine inhibited breast cancer cells growth, migration and invasion as well as induced their apoptosis.In in vivo study, lycorine not only suppressed breast tumor growth in xenograft models and inhibited breast tumor metastasis in MDA-MB-231 tail vein model. More importantly, we found lycorine had less toxicity than first-line chemotherapy drug paclitaxel at the same effective dose in vivo. Furthermore, on mechanism, lycorine inhibited tumor cell migration and invasion via blocking the Src/FAK(focal adhesion kinase)-involved pathway. In conclusion, our study implied lycorine was a potential candidate for the treatment of breast cancer by inhibition of tumor growth and metastasis.     

Anti-inflammatory properties and regulatory mechanism of a novel derivative of artemisinin in experimental autoimmune encephalomyelitis

Ethyl 2-[4-(12-beta-artemisininoxy)]phenoxylpropionate (SM933) is a novel derivative of artemisinin, an herbal compound approved for the treatment of malaria. In this study, we show that SM933 has unique anti-inflammatory properties through regulation of signaling pathways, leading to amelioration of experimental autoimmune encephalomyelitis. The anti-inflammatory properties of SM933 were characterized by inhibition of encephalitogenic T cell responses that were altered to exhibit a Th2 immune deviation and reduced activity and concentration of NO and inducible NO synthase. The observed effect of SM933 was mediated through regulatory mechanisms involving the NFkappaB and the Rig-G/JAB1 signaling pathways. SM933 was found to inhibit the activity of NFkappaB by up-regulating IkappaB, which accounted for various down-stream anti-inflammatory actions. Furthermore, it up-regulated Rig-G through the action of IFN-alpha and prevented JAB1, a master cell cycle regulator, from entering the nucleus to promote p27 degradation, resulting in down-regulation of CDK2 and cyclin A and cell cycle progression. Regulation of the Rig-G/JAB1 pathway by SM933 led to altered cell cycle activity of encephalitogenic T cells as a result of its selective effect on activated, but not resting, T cells. The study indicates that SM933 is a novel anti-inflammatory agent acting through defined signaling mechanisms and provides regulatory mechanisms required for effective drug targeting in treatment of autoimmune disease and inflammation.     

Adventitious shoot regeneration from in vitro leaf explants of <Emphasis Type="Italic">Fraxinus nigra</Emphasis>

In order to establish an attractive method for the production of valuable medicinal alkaloids (galanthamine and lycorine), the plants of Leucojum aestivum and L. aestivum ‘Gravety Giant’ grown in bioreactor RITA® were subjected to various concentrations of methyl jasmonate (MeJA), salicylic acid (SA), 1-aminocyclopropane-1-carboxylic acid (ACC) and 2-chloroethylphosphonic acid (ethephon) at different times of culture. The application of MeJA showed a negative effect on L. aestivum and L. aestivum ‘Gravety Giant’ plant growth. We observed that the incubation of plants during 168 h with 100 µM of MeJA resulted above two times lower F.W. (fresh weight) increments compared with control. While SA showed an inhibitory effect only on the growth of L. aestivum cultures. ACC and ethephon had a positive effect on both types of culture. Treatment with 50 µM of MeJA during 168 h stimulated galanthamine and lycorine biosynthesis in L. aestivum and L. aestivum ‘Gravety Giant’ cultures. In addition, the accumulation of galanthamine was increased when 10 µM of ACC were added to both types of culture. 10 µM of ACC stimulated also lycorine biosynthesis by L. aestivum ‘Gravety Giant’. The addition of 10 µM of ethephon had a positive effect only on lycorine production in plants of L. aestivum. SA promoted galanthamine and lycorine biosynthesis in tested plants. Indeed the highest galanthamine (0.8 mg/g dry weight: D.W.) and lycorine (1.53 mg/g D.W.) concentrations were observed in L. aestivum ‘Gravety Giant’ plants treated with 5 µM of SA during 10 h.