RNA干扰在功能基因组学和疾病基因治疗中应用进展

RNA干扰 (RNAi)是由双链小分子干扰RNA片段引发的特异性基因沉默 ,是一种转录后基因沉默机制。RNAi是一种生物体广泛存在的基因调控机制 ,参与了机体正常发育和抵抗外源性病毒入侵等多种生命活动。作为一种简单、高效的代替基因敲除的遗传工具 ,RNAi正在功能基因组学和疾病基因治疗领域掀起一场革命 ,并将彻底改变这些领域的研究步伐。该文重点介绍了RNAi在功能基因组学和疾病基因治疗中应用进展。     

Phase I and pharmacologic study of the human DNA methyltransferase antisense oligodeoxynucleotide MG98 given as a 21-day continuous infusion every 4 weeks

Purpose: MG98 is a second generation phosphorothioate antisense oligodeoxynucleotide which is a highly specific inhibitor of translation of the mRNA for human DNA MeTase I (DNMT 1). This phase I study examined the toxicity and pharmacologic profile of MG98 administered as a continuous 21-day intravenous infusion every 4 weeks. Patients and methods: Fourteen patients with solid cancers received a total of 25 cycles of MG98 at doses ranging from 40 to 240 mg/m²/day. Steady-state concentrations of MG98 were measured as were several pharmacodynamic assessments including mRNA of the target gene, DNMT1, in PBMC. In addition, other potential surrogate markers of drug effects were explored, including hemoglobin F, Vimentin and GADD45. Results: Dose limiting effects were drug-related reversible transaminase elevation and fatigue seen at doses of 240, 200 and 160 mg/m²/day. The dose level of 80 mg/m²/day was felt to be safe and tolerable when delivered on this schedule. No evidence of antitumor activity was observed. Although pharmacokinetic analysis revealed that at the higher dose levels, mean Css values of MG98 were approximately 10-fold times the IC₅₀ values associated with target inhibition in vitro, the extent of MG98 penetration into target tumors in this trial was not determined. No consistent, dose-related changes in correlative markers including DNMT1 mRNA, hemoglobin F, Vimentin and GADD45, were observed. Conclusions: This schedule of MG98 given as a 21-day continuous intravenous infusion every 4 weeks was poorly tolerated in the highest doses; therefore, further disease-site specific evaluation of the efficacy of this agent will utilize a more favorable, intermittent dosing schedule. Pharmacodynamic evaluations undertaken in an attempt to explore and validate the biological mechanisms of MG98 did not show dose-related effects.     

肠道病毒71型感染的药物治疗和疫苗预防

肠道病毒71型(EV71)是引起手足口病的重要病原,能引发严重的神经系统并发症甚至死亡,构成严重的危害,但目前对ET71尚无有效的抗病毒治疗策略.此文就抗EV71的药物、疫苗及RNA干扰技术的研究进展作了综述,为EV71的防治工作提供借鉴.     

红景天提取物对胰岛素抵抗大鼠肝脏过氧化物酶体增殖物激活受体-γmRNA 表达的影响

目的：观察中药红景天提取物对高脂饮食诱导的胰岛素抵抗大鼠胰岛素敏感性及过氧化物酶体增殖物激活受体-γ（ PPAR-γ） mRNA表达的影响。方法将70只Wistar大鼠随机分为2组,正常对照组20只,高脂模型组50只。正常对照组给予基础饲料,高脂模型组给予高脂饲料,均喂养4周后2组各随机选取10只大鼠行高胰岛素-正葡萄糖钳夹试验判断造模是否成功,确认造模成功后将剩余高脂模型组大鼠随机分为高脂对照组和高脂＋红景天干预组,每组20只。高脂＋红景天干预组给予红景天提取物1 g/（ kg ＆#183; d）灌胃,正常对照组及高脂对照组给予等容积0．9％氯化钠注射液灌胃,其他饲养条件不变,继续喂养4周。观察比较各组大鼠造模后和灌胃4周后血清甘油三酯（ TG）、血清总胆固醇（ TC）、游离脂肪酸（ FFA）、空腹血糖（ FPG）及空腹血清胰岛素（ FINS）的含量变化,并记录葡萄糖输注率（ GIR）变化及PPAR-γmRNA的表达情况。结果高脂模型组大鼠造模后与正常对照组比较FPG、FINS明显升高（P＜0．05）,GIR明显下降（P＜0．05）;高脂对照组灌胃4周后与正常对照组比较TG、TC及FFA水平均明显升高（P＜0．05）,高脂＋红景天干预组较高脂对照组TC、TG及FFA水平均明显下降（P＜0．05）,与正常对照组水平相当（P＞0．05）;高脂对照组灌胃4周后与正常对照组比较FPG、FINS明显升高（P＜0．05）,GIR明显下降（P＜0．05）,高脂＋红景天干预组较高脂对照组FPG、FINS水平明显下降（P＜0．05）,GIR明显升高（P＜0．05）,与正常对照组水平相当相（P＞0．05）;高脂对照组灌胃4周后PPAR-γmRNA表达水平与正常对照组表达水平相当（P＞0．05）,高脂＋红景天干预组较正常对照组及高脂对照组比较PPAR-γmRNA表达水平均有明显升高（P＜0．05）。结论红景天提取物对大鼠的     

靶向VEGF发夹状RNA对宫颈癌HeLa细胞抑制作用的研究

目的:运用RNAi技术下调血管内皮生长因子(VEGF)在HeLa细胞中的表达,观察其对肿瘤细胞凋亡的影响,为人宫颈癌治疗提供理论依据。方法:设计并构建针对VEGF的携带绿色荧光蛋白(GFP)发夹状RNA(shRNA)质粒表达载体(PGPU6/GFP/Neo-shRNA),脂质体法转染HeLa细胞;荧光显微镜观察GFP的表达,并计算转染效率;RT-PCR检测HeLa细胞VEGF的表达,筛选出靶序列;再用流式细胞仪法检测细胞凋亡。结果:构建的PGPU6/GFP/Neo载体成功转入HeLa细胞;转染48h后,HeLa-shVEGF1组HeLa细胞VEGFmRNA表达的抑制率为75.0%;与HeLa组和HeLa-shNC组相比,HeLa-shVEGF1组HeLa细胞凋亡率明显增加,P<0.01。结论:本研究构建的PGPU6-shRNA表达载体携带GFP便于观察细胞的转染情况,且不影响U6启动子的转录,同时有效沉默了VEGF基因,明显增加HeLa细胞的凋亡,为未来肿瘤的治疗提供新途径。     

肺腺癌中关键lncRNA的表达及免疫相关分析

目的:通过鉴定与肺腺癌（LUAD）预后相关的长非编码RNA（lncRNA）,研究LUAD的发生机制及其预后意义,确定与LUAD预后相关的敏感性生物标志物,并对其进行免疫途径相关性分析。方法:从肿瘤基因组图谱数据库(TCGA)中获取与LUAD相关的数据,通过单因素Cox回归分析及套索算法（LASSO）筛选lncRNA,使用多因素Cox回归进行预后风险评分分析,建立预后风险模型,用计算曲线下面积（AUC）和Kaplan-Meier（K-M）生存分析方法评价模型的稳健性和准确性。利用K-M生存分析方法确定与生存状态相关的潜在生物标志物,并通过ImmLnc平台对其进行免疫途径相关性研究。结果:从49个与生存相关的lncRNAs中确定了12个预后相关生物标志物,通过K-M生存分析,MIR34AHG和PRKCA-AS1被确定为与预后相关的生物标志物(P＜0.05)。模型的3年和5年生存率的AUC分别为0.82和0.846。与MIR34AHG相关的免疫途径分别为“细胞因子受体”(P＜0.05),“抗原处理和提呈”(P＜0.05),与PRKCA-AS1相关的免疫途径为“抗原处理和提呈”(P＜0.05)。结论:通过对生物信息大数据的分析,我们确定了两个关键lncRNAs及其相关的免疫途径,为LUAD的预后评估提供了新的生物标志物。     

Immunomodulatory and anti-SARS activities of Houttuynia cordata

BACKGROUND: Severe acute respiratory syndrome (SARS) is a life-threatening form of pneumonia caused by SARS coronavirus (SARS-CoV). From late 2002 to mid 2003, it infected more than 8000 people worldwide, of which a majority of cases were found in China. Owing to the absence of definitive therapeutic Western medicines, Houttuynia cordata Thunb. (Saururaceae)(HC) was shortlisted by Chinese scientists to tackle SARS problem as it is conventionally used to treat pneumonia. AIM OF THE STUDY: The present study aimed to explore the SARS-preventing mechanisms of HC in the immunological and anti-viral aspects. RESULTS: Results showed that HC water extract could stimulate the proliferation of mouse splenic lymphocytes significantly and dose-dependently. By flow cytometry, it was revealed that HC increased the proportion of CD4(+) and CD8(+) T cells. Moreover, it caused a significant increase in the secretion of IL-2 and IL-10 by mouse splenic lymphocytes. In the anti-viral aspect, HC exhibited significant inhibitory effects on SARS-CoV 3C-like protease (3CL(pro)) and RNA-dependent RNA polymerase (RdRp). On the other hand, oral acute toxicity test demonstrated that HC was non-toxic to laboratory animals following oral administration at 16 g/kg. CONCLUSION: The results of this study provided scientific data to support the efficient and safe use of HC to combat SARS.     

超声靶向破坏微泡技术介导小鼠肝癌细胞株JNK1基因表达、细胞迁移和侵袭抑制

目的: 探讨应用超声靶向破坏微泡 (UTMD) 技术介导小鼠肝癌细胞株JNK1基因的表达、细胞迁移和侵袭抑制的作用,阐明其作用机制。方法: 构建并筛选RNA干扰效果最好的短发夹RNA(shRNA)。将小鼠肝癌细胞株Hca-F分为正常Hca-F细胞组、shRNA质粒组、脂质体组、超声微泡结合超声辐照组及脂质体结合超声微泡加超声辐照组。采用倒置荧光显微镜观察各组细胞转染率,荧光定量PCR和Western blotting 法检测JNK1基因mRNA和蛋白表达水平,CCK-8法检测各组细胞的细胞活性,应用Transwell 实验检测各组细胞的体外迁移能力。结果: 脂质体结合超声微泡加超声辐照组细胞转染率高于shRNA质粒组、脂质体组和超声微泡结合超声辐照组(均P<0.05),脂质体组和超声微泡结合超声辐照组比较差异无统计学意义(P>0.05)。脂质体结合超声微泡加超声辐照组JNK1 mRNA和蛋白表达水平低于其他各组(P<0.05);脂质体结合超声微泡加超声辐照组细胞活性和平均穿膜细胞数均低于其他各组(P<0.05)。结论: UTMD技术结合脂质体转染法可以提高小鼠肝癌细胞株JNK1 shRNA的转染效率,增强其对基因表达、细胞活力、迁移和侵袭能力的抑制。     

探讨不同实验条件对U87细胞体外增殖的影响

目的:探讨RNA干扰肝癌衍生生长因子(HDGF)后,U87细胞增殖抑制的最佳实验条件。方法:用LipofectamineTM2000将HDGF siRNA转染U87细胞后,将细胞接种于96孔板中,分别在无血清、含10%FBS和无血清Matrigel胶预处理细胞培养板条件下,采用MTS法检测细胞增殖能力。结果:HDGF表达水平下调后,U87细胞增殖能力受到抑制。在无血清、含10%FBS和无血清Matrigel胶预处理细胞培养板条件下,细胞增殖抑制率分别是18%、9%和28%。结论:在无血清Matrigel胶预先处理的培养条件下,能最大程度上反映出HDGFsiRNA对U87细胞增殖能力的抑制。     

Single-Domain Antibodies as Therapeutics for Respiratory RNA Virus Infections

Over the years, infectious diseases with high morbidity and mortality disrupted human healthcare systems and devastated economies globally. Respiratory viruses, especially emerging or re-emerging RNA viruses, including influenza and human coronavirus, are the main pathogens of acute respiratory diseases that cause epidemics or even global pandemics. Importantly, due to the rapid mutation of viruses, there are few effective drugs and vaccines for the treatment and prevention of these RNA virus infections. Of note, a class of antibodies derived from camelid and shark, named nanobody or single-domain antibody (sdAb), was characterized by smaller size, lower production costs, more accessible binding epitopes, and inhalable properties, which have advantages in the treatment of respiratory diseases compared to conventional antibodies. Currently, a number of sdAbs have been developed against various respiratory RNA viruses and demonstrated potent therapeutic efficacy in mouse models. Here, we review the current status of the development of antiviral sdAb and discuss their potential as therapeutics for respiratory RNA viral diseases.