miR-181b-5p调控TIMP3对apoE~(-/-)鼠动脉粥样硬化炎症影响及相关因子检验

为探究mi R-181b-5p靶向调控TIMP3对apo E~(-/-)鼠动脉粥样硬化炎症的影响,本研究基于生物信息学预测筛选,并采用双荧光素酶报告基因系统验证mi R-181b-5p靶基因。同时在ox-LDL刺激THP-1巨噬细胞及apo E~(-/-)动脉粥样硬化模型小鼠中检测mi R-181b-5p靶基因m RNA及蛋白水平的表达情况,并且检测转染mi R-181b-5p后细胞水平和动物体内炎症因子TNF-α、INF-γ、IL-1β、IL-18、CCL2的表达变化。此外,通过病理切片方法检测转染mi R-181b-5p后小鼠主动脉窦处病变情况。研究通过双荧光素酶报告基因系统验证TIMP3为mi R-181b-5p靶基因,并在ox-LDL刺激THP-1巨噬细胞及apo E~(-/-)动脉粥样硬化模型小鼠中证明了mi R-181b-5p可以降低TIMP3转录水平从而降低其蛋白水平表达,同时研究发现mi R-181b-5p在细胞水平和动物体内均会增强炎症因子TNF-α、INF-γ、IL-1β、IL-18、CCL2的表达,并可以增加小鼠主动脉窦处病变面积。研究认为在动脉粥样硬化发生中,mi R-181b-5p可以增加病变面积并且提升相关炎症因子的表达、分泌,其作用机理很可能是通过抑制靶基因TIMP3表达,进而降低TIMP3蛋白水平实现的,为研究动脉粥样硬化机制提供了理论依据。     

miR-106b-93-25簇对子宫内膜癌细胞的调控作用研究

目的:检测mi R-106b-93-25基因簇对子宫内膜癌细胞增殖及凋亡的影响,并探讨其机制。方法:q RT-PCR检测临床子宫内膜癌标本及癌旁正常组织中mi R-106b、mi R-93和mi R-25及其宿主基因MCM7的表达情况。将micro RNA及其拮抗剂转染ECC-1细胞后,MTT实验检测ECC-1细胞增殖情况,流式细胞术检测ECC-1细胞周期及细胞凋亡情况。荧光素酶报告系统验证mi R-106b和mi R-25分别直接调控p21和Bim。结果:临床标本子宫内膜癌组织与癌旁正常组织相比mi R-106b-93-25簇及其宿主基因MCM7的表达明显增高。mi R-106b-93-25簇能够促进ECC-1细胞增殖,减少凋亡。转染mi R-106b和mi R-93的细胞出现明显的S期阻滞,过表达mi R-25的细胞凋亡明显减少。mi R-106b-93-25簇通过抑制靶基因p21和Bim的表达,引起促增殖、抗凋亡作用。结论:mi R-106b-93-25簇能够促进子宫内膜癌细胞增殖,抑制凋亡,并使细胞发生S期阻滞。mi R-106b-93-25簇在子宫内膜癌的发生与发展中具有重要的作用。     

miR-181a调控骨髓间充质干细胞中OPG水平及对破骨细胞活性的影响

该研究预测并验证骨髓间充质干细胞(bone marrow mesenchymal stem cells,BMMSCs)中mi R-181a对靶分子骨保护素(osteoprotegerin,OPG)m RNA水平的调控作用,探讨其在骨质疏松发病过程中对破骨细胞活性的影响。通过生物信息学预测mi R-181a可能调控的靶基因OPG,构建含mi R-181a结合位点的OPG m RNA 3′UTR(3′untranslated regions)荧光素酶报告载体。通过双荧光素酶载体系统检测mi R-181a与OPG m RNA 3′UTR相互作用对荧光素酶活性的影响;转染mi R-181a进入BMMSCs并与破骨细胞共培养,TRAP(tartrate resistant acid phosphatase)染色检测共培养体系中破骨细胞数目的改变。结果表明,双荧光素酶报告提示,mi R-181a的靶分子为OPG m RNA,上调mi R-181a(mimics组)水平后,破骨细胞数目较对照组显著增多(P0.05);下调mi R-181a(inhibitor组)水平后,破骨细胞数目较对照组显著降低(P0.05)。研究结果显示,mi R-181a可以负调控OPG的蛋白水平,进而影响破骨细胞活性。     

小鼠精子发生早期microRNA的表达谱和调控模式——miRNA在小鼠精子发生中的作用

精子发生是一个依赖于精原干细胞自我更新和精原细胞分化的精确而又复杂的调控过程,目前对这一过程知之甚少.mi RNA作为转录和转录后基因沉默的关键调节子,参与很多生物的多种发育过程.本研究采用高通量小RNA测序系统研究了mi RNA在小鼠B型精原细胞(BSc)和初级精母细胞(PSc)中的表达谱.结果显示,在这2种细胞类型中let-7mi RNA家族的表达水平都相当高.并且在BSc向PSc的转化过程中,mi R-21,mi R-140-3p,mi R-103,mi R-30a,mi R-101b和mi R-99b的表达水平明显降低.这些mi RNA参与调控与细胞凋亡、细胞增殖和分化、连接组装和细胞周期调控相关的诸多基因的表达.上述结果表明,mi RNAs在精子发生过程中发挥着不可替代的作用.     

DLX6-AS1通过竞争性结合miR-15上调Caspase-1诱导巨噬细胞焦亡

为探讨长链非编码RNA (long noncoding RNA, lncRNA) DLX6-AS1在巨噬细胞焦亡中的作用及相关机制,采用生物信息学分析、实时荧光定量PCR和双荧光素酶报告基因实验等,在THP-1巨噬细胞中分析并验证lncRNA DLX6-AS1下游微RNA (microRNA, mi RNA)及mi RNA的下游靶基因;通过免疫荧光染色等实验检测DLX6-AS1/miR-15/caspase-1轴对巨噬细胞焦亡的影响。结果显示, DLX6-AS1在焦亡巨噬细胞中表达上调,敲降DLX6-AS1可抑制巨噬细胞焦亡,但这种抑制作用被mi R-15抑制剂逆转; mi R-15通过调控其靶基因caspase-1表达,抑制巨噬细胞焦亡。本研究表明, DLX6-AS1通过竞争性结合mi R-15,解除mi R-15对其靶基因caspase-1的抑制作用,从而诱导巨噬细胞焦亡,这将丰富lncRNA调控巨噬细胞焦亡的理论基础。     

靶向Wnt1的miRNA与circRNA及其靶基因间相互作用的生物信息学分析

为对靶向Wnt1的7种mi RNAs进行circ RNAs及其靶基因的预测,同时分析其与circ RNAs及靶基因间的相互作用,分别采用Starbase及mi RWALK软件,对文献报道的靶向Wnt1基因的let-7e、mi R-21、mi R-34a、mi R-122、mi R-148a、mi R-148b与mi R-152等7种mi RNAs的circ RNAs和对应的靶基因进行生物信息学预测.利用Cytoscape 3.2.1对这7种mi RNAs和预测所得到的circ RNAs及对应的靶基因进行网络分析.并进一步对预测到的靶基因通过DAVID软件进行通路分析.Starbase软件对这7种不同mi RNAs所预测的靶circ RNAs的数量分别为58、15、41、20、28、28、28个.分别比较mi RWALK中7~9个以上软件共有的mi RNAs及其与靶基因的关系,发现CHD7基因是唯一一个在三种不同预测范围内与mi R-21、mi R-148a、mi R-148b和mi R-152等4种mi RNAs相对应的靶基因.CNOT6、NBEA、ZFYVE26与ZDHHC17是在两种不同预测范围内与至少4个mi RNAs相对应的靶基因.在7种mi RNAs所预测靶基因相关的KEGG信号通路中,7~9个软件以上共有的信号通路为Focal adhesion信号通路、MAPK信号通路、Notch信号通路与TGF-beta信号通路.在MAPK信号通路中DUSP1与MRPS35_hsa_circ_001042均分别是与mi R-21、mi R-148a、mi R-148b及mi R-152等4种mi RNAs相互作用的靶基因与circ RNA.本研究对靶向Wnt1的mi RNAs及其相互作用的circ RNAs、靶基因与信号通路等进行了网络分析与预测,为进一步分析它们之间的相互作用奠定了基础.     

miR-199a-3p/Nme2在TGF-β1信号通路中的作用分析

通过microRNA芯片技术在小鼠GC-1 spg细胞中筛选发现microRNA-199a-3p(miR-199a-3p)受转化生长因子TGF-β1调节。为了进一步探讨二者的关系,通过基因克隆与载体构建技术、双荧光素酶报告基因检测及定量PCR实验,发现miR-199a-3p靶向识别肿瘤转移抑制基因2(Nme2)的3'非编码区(UTR)序列,且正向调控Nme2的表达。利用TGF-β1处理GC-1 spg细胞后,结果显示Nme2和miR-199a-3p在mRNA水平的表达均显著上调;进一步将miR-199a-3p和TGF-β1双重作用于GC-1 spg细胞后,结果表明Nme2的表达会明显增强,而且在TGF-β1通路中,miR-199a-3p被抑制的部分功能可能会被Nme2补偿。综上,miR-199a-3p对Nme2基因具有直接靶向识别和调控作用,且在参与TGF-β1信号通路的生物学效应中,二者在功能上相互关联。     

抑癌因子miR-10a抑制Tiam1表达对胃癌细胞凋亡和迁移的影响

目的:探讨miR-10a抑制Tiam1表达对胃癌细胞凋亡和侵袭的影响。方法:获取胃上皮组织细胞及胃癌组织细胞,利用q PCR及Western blot实验检测两种细胞中mi R-10a表达与Tiam1的m RNA及蛋白表达水平,同时检测胃癌细胞S746T及正常胃粘膜细胞RGM-1和NGEC中mi R-10a表达与Tiam1蛋白表达水平。通过将mi R-10a mimic和mi R-10a inhibitor转染HS746T细胞,利用流式细胞术检测HS746T的细胞周期和细胞凋亡,TranswellTM实验检测HS746T细胞的侵袭能力,qPCR及Western blot实验检测凋亡相关蛋白caspase3、caspase9和Bax以及周期相关蛋白P21表达水平;荧光素酶活性分析实验检测Tiam1是mi R-10a的作用靶点。已构建的Tiam1高表达的Tiam1-pcDNA3.1质粒和敲除Tiam1基因的PX458质粒分别转染HS746T细胞,通过流式细胞术及TranswellTM实验检测HS746T细胞的凋亡及侵袭能力。结果:与胃上皮组织细胞相比,早期胃癌临床组织细胞中mi R-10a表达降低,Tiam1的m RNA及蛋白表达升高;mi R-10a的表达与早期胃癌患者的肿瘤转移密切相关,与年龄、性别和肿瘤分期无关;与正常胃粘膜细胞RGM-1和NGEC相比,胃癌细胞HS746T中的mi R-10a表达降低,而Tiam1蛋白表达升高;mi R-10a可抑制HS746T细胞侵袭,促进细胞凋亡,使其停滞于G0/G1期;mi R-10a靶向作用于Tiam1基因的3'非翻译区(3'UTR),减少Tiam1的蛋白表达;Tiam1可抑制HS746T细胞凋亡,促进HS746T细胞侵袭。结论:mi R-10a靶向作用于Tiam1基因的3'UTR,抑制HS746T细胞的增殖及侵袭,促进HS746T细胞凋亡。     

miR-10a对类风湿性关节炎滑膜细胞侵袭、迁移能力的影响及机制

目的:以类风湿性关节炎(RA)患者滑膜细胞为研究对象,明确mi R-10a对滑膜细胞侵袭、迁移能力的影响及机制。方法:首先用q RT-PCR对筛选得到的异常表达mi RNA进行验证,进而利用生物信息学分析结合报告基因、Western印迹方法,明确mi R-10a的靶基因,最后采用Transwell、划痕实验考察mi R-10a对RA成纤维细胞样滑膜细胞(FLS细胞)侵袭能力的影响。结果:mi R-10a在RA患者滑膜组织及细胞中低表达;TAK1和BTRC是mi R-10a的靶基因;mi R-10a可促进IL-6、IL-8等炎症因子的表达;mi R-10a可促进FLS细胞的侵袭、迁移。结论:mi R-10a可通过调节NF-κB的活性影响RA FLS细胞的侵袭、迁移。     

miR-17-92、自噬在肿瘤中的研究进展

micro RNA(mi RNA)是一类在转录后水平调控目的基因表达的功能性小RNA分子。mi R-17-92基因簇是一个高度保守的基因簇,编码6个mi RNAs,分别为:mi R-17、mi R-18a、mi R-19a、mi R-19b-1、mi R-20a和mi R-92a。细胞自噬(autophagy)是将细胞内受损、变性或衰老的蛋白质以及细胞器运输到溶酶体进行消化降解的过程。mi RNA的异常表达可影响自噬水平,从而影响肿瘤的发生发展。研究证明mi R-17-92基因簇与细胞自噬及肿瘤的发生密切相关,有望成为具有潜在价值的肿瘤标志物或肿瘤治疗的新靶点。现对mi R-17-92基因簇与细胞自噬和肿瘤的关系进行综述。     

DEC1 and MIC-1

Comment on: Qian Y, et al. Proc Natl Acad Sci USA 2012; 109:11300-5.     

LINE-1编码蛋白L1-ORF1的原核表达纯化和多克隆抗体制备

目的: 制备具有肿瘤组织特异性表达的L1-ORF1蛋白多克隆抗体并进行初步应用研究。方法:采取基因工程表达方法制备L1-ORF1蛋白,免疫家兔制备多克隆抗体,间接ELISA检测抗体效价,Western blot和细胞免疫荧光方法检测抗体特异性,免疫检测验证其识别肿瘤细胞内L1-ORF1蛋白的特异性。结果:制备的抗L1-ORF1蛋白多克隆抗体具有很高的敏感性与特异性,免疫学检测表明该抗体不仅能检测出正常细胞中瞬时表达的L1-ORF1蛋白,而且可检测出肿瘤细胞中天然表达的L1-ORF1蛋白。结论:制备的多克隆抗体具有较高的敏感性与特异性,为以后该抗体的进一步应用奠定了基础。     

Role of the ASK1-SEK1-JNK1-HIPK1 signal in Daxx trafficking and ASK1 oligomerization

Overexpression of JNK binding domain inhibited glucose deprivation-induced JNK1 activation, relocalization of Daxx from the nucleus to the cytoplasm, and apoptosis signal-regulating kinase 1 (ASK1) oligomerization in human prostate adenocarcinoma DU-145 cells. However, SB203580, a p38 inhibitor, did not prevent relocalization of Daxx and oligomerization of ASK1 during glucose deprivation. Studies from in vivo labeling and immune complex kinase assay demonstrated that phosphorylation of Daxx occurred during glucose deprivation, and its phosphorylation was mediated through the ASK1-SEK1-JNK1-HIPK1 signal transduction pathway. Data from immunofluorescence staining and protein interaction assay suggest that phosphorylated Daxx may be translocated to the cytoplasm, bind to ASK1, and subsequently lead to ASK1 oligomerization. Mutation of Daxx Ser667 to Ala results in suppression of Daxx relocalization during glucose deprivation, suggesting that Ser667 residue plays an important role in the relocalization of Daxx. Unlike wild-type Daxx, a Daxx deletion mutant (amino acids 501-625) mainly localized to the cytoplasm, where it associated with ASK1, activated JNK1, and induced ASK1 oligomerization without glucose deprivation. Taken together, these results show that glucose deprivation activates the ASK1-SEK1-JNK1-HIPK1 pathway, and the activated HIPK1 is probably involved in the relocalization of Daxx from the nucleus to the cytoplasm. The relocalized Daxx may play an important role in glucose deprivation-induced ASK1 oligomerization.     

Antagonism between Cry1Ac1 and Cyt1A1 toxins of bacillus thuringiensis

Most strains of the insecticidal bacterium Bacillus thuringiensis have a combination of different protoxins in their parasporal crystals. Some of the combinations clearly interact synergistically, like the toxins present in B. thuringiensis subsp. israelensis. In this paper we describe a novel joint activity of toxins from different strains of B. thuringiensis. In vitro bioassays in which we used pure, trypsin-activated Cry1Ac1 proteins from B. thuringiensis subsp. kurstaki, Cyt1A1 from B. thuringiensis subsp. israelensis, and Trichoplusia ni BTI-Tn5B1-4 cells revealed contrasting susceptibility characteristics. The 50% lethal concentrations (LC50s) were estimated to be 4,967 of Cry1Ac1 per ml of medium and 11.69 ng of Cyt1A1 per ml of medium. When mixtures of these toxins in different proportions were assayed, eight different LC50s were obtained. All of these LC50s were significantly higher than the expected LC50s of the mixtures. In addition, a series of bioassays were performed with late first-instar larvae of the cabbage looper and pure Cry1Ac1 and Cyt1A1 crystals, as well as two different combinations of the two toxins. The estimated mean LC50 of Cry1Ac1 was 2.46 ng/cm2 of diet, while Cyt1A1 crystals exhibited no toxicity, even at very high concentrations. The estimated mean LC50s of Cry1Ac1 crystals were 15.69 and 19.05 ng per cm2 of diet when these crystals were mixed with 100 and 1,000 ng of Cyt1A1 crystals per cm2 of diet, respectively. These results indicate that there is clear antagonism between the two toxins both in vitro and in vivo. Other joint-action analyses corroborated these results. Although this is the second report of antagonism between B. thuringiensis toxins, our evidence is the first evidence of antagonism between toxins from different subspecies of B. thuringiensis (B. thuringiensis subsp. kurstaki and B. thuringiensis subsp. israelensis) detected both in vivo and in vitro. Some possible explanations for this relationship are discussed.     

Regulation of PCTAIRE1 protein stability by AKT1, LKB1 and BRCA1

PCTAIRE1, also known as CDK16, is a cyclin-dependent kinase that is regulated by cyclin Y. It is a member of the serine-threonine family of kinases and its functions have primarily been implicated in cellular processes like vesicular transport, neuronal growth and development, myogenesis, spermatogenesis and cell proliferation. However, as extensive studies on PCTAIRE1 have not yet been conducted, the signaling pathways for this kinase involved in governing many cellular processes are yet to be elucidated in detail. Here, we report the association of PCTAIRE1 with important cellular proteins involved in major cell signaling pathways, especially cell proliferation. In particular, here we show that PCTAIRE1 interacts with AKT1, a key player of the PI3K signaling pathway that is responsible for promoting cell survival and proliferation. Our studies show that PCTAIRE1 is a substrate of AKT1 that gets stabilized by it. Further, we show that PCTAIRE1 also interacts with and is degraded by LKB1, a kinase that is known to suppress cellular proliferation and also regulate cellular energy metabolism. Moreover, our results show that PCTAIRE1 is also degraded by BRCA1, a well-known tumor suppressor. Together, our studies highlight the regulation of PCTAIRE1 by key players of the major cell signaling pathways involved in regulating cell proliferation, and therefore, provide crucial links that could be explored further to elucidate the mechanistic role of PCTAIRE1 in cell proliferation and tumorigenesis.     

Antagonism between Cry1Ac1 and Cyt1A1 Toxins of Bacillus thuringiensis

Most strains of the insecticidal bacterium Bacillus thuringiensis have a combination of different protoxins in their parasporal crystals. Some of the combinations clearly interact synergistically, like the toxins present in B. thuringiensis subsp. israelensis. In this paper we describe a novel joint activity of toxins from different strains of B. thuringiensis. In vitro bioassays in which we used pure, trypsin-activated Cry1Ac1 proteins from B. thuringiensis subsp. kurstaki, Cyt1A1 from B. thuringiensis subsp. israelensis, and Trichoplusia ni BTI-Tn5B1-4 cells revealed contrasting susceptibility characteristics. The 50% lethal concentrations (LC₅₀s) were estimated to be 4,967 of Cry1Ac1 per ml of medium and 11.69 ng of Cyt1A1 per ml of medium. When mixtures of these toxins in different proportions were assayed, eight different LC₅₀s were obtained. All of these LC₅₀s were significantly higher than the expected LC₅₀s of the mixtures. In addition, a series of bioassays were performed with late first-instar larvae of the cabbage looper and pure Cry1Ac1 and Cyt1A1 crystals, as well as two different combinations of the two toxins. The estimated mean LC₅₀ of Cry1Ac1 was 2.46 ng/cm² of diet, while Cyt1A1 crystals exhibited no toxicity, even at very high concentrations. The estimated mean LC₅₀s of Cry1Ac1 crystals were 15.69 and 19.05 ng per cm² of diet when these crystals were mixed with 100 and 1,000 ng of Cyt1A1 crystals per cm² of diet, respectively. These results indicate that there is clear antagonism between the two toxins both in vitro and in vivo. Other joint-action analyses corroborated these results. Although this is the second report of antagonism between B. thuringiensis toxins, our evidence is the first evidence of antagonism between toxins from different subspecies of B. thuringiensis (B. thuringiensis subsp. kurstaki and B. thuringiensis subsp. israelensis) detected both in vivo and in vitro. Some possible explanations for this relationship are discussed.     

Dial 9-1-1 for DNA damage: the Rad9-Hus1-Rad1 (9-1-1) clamp complex

Genotoxic stress activates checkpoint signaling pathways that block cell cycle progression, trigger apoptosis, and regulate DNA repair. Studies in yeast and humans have shown that Rad9, Hus1, Rad1, and Rad17 play key roles in checkpoint activation. Three of these proteins-Rad9, Hus1, and Rad1-interact in a heterotrimeric complex (dubbed the 9-1-1 complex), which resembles a PCNA-like sliding clamp, whereas Rad17 is part of a clamp-loading complex that is related to the PCNA clamp loader, replication factor-C (RFC). In response to genotoxic damage, the 9-1-1 complex is loaded around DNA by the Rad17-containing clamp loader. The DNA-bound 9-1-1 complex then facilitates ATR-mediated phosphorylation and activation of Chk1, a protein kinase that regulates S-phase progression, G2/M arrest, and replication fork stabilization. In addition to its role in checkpoint activation, accumulating evidence suggests that the 9-1-1 complex also participates in DNA repair. Taken together, these findings suggest that the 9-1-1 clamp is a multifunctional complex that is loaded onto DNA at sites of damage, where it coordinates checkpoint activation and DNA repair.