Let-7a gene knockdown protects against cerebral ischemia/reperfusion injury

The micro RNA（mi RNA） let-7 was one of the first mi RNAs to be discovered, and is highly conserved and widely expressed among species. let-7 expression increases in brain tissue after cerebral ischemia/reperfusion injury; however, no studies have reported let-7 effects on nerve injury after cerebral ischemia/reperfusion injury. To investigate the effects of let-7 gene knockdown on cerebral ischemia/reperfusion injury, we established a rat model of cerebral ischemia/reperfusion injury. Quantitative reverse transcription-polymerase chain reaction demonstrated that 12 hours after cerebral ischemia/reperfusion injury, let-7 expression was up-regulated, peaked at 24 hours, and was still higher than that in control rats after 72 hours. Let-7 gene knockdown in rats suppressed microglial activation and inflammatory factor release, reduced neuronal apoptosis and infarct volume in brain tissue after cerebral ischemia/reperfusion injury. Western blot assays and luciferase assays revealed that mitogen-activated protein kinase phosphatase-1（MKP1） is a direct target of let-7. Let-7 enhanced phosphorylated p38 mitogen-activated protein kinase（MAPK） and c-Jun N-terminal kinase（JNK） expression by down-regulating MKP1. These findings suggest that knockdown of let-7 inhibited the activation of p38 MAPK and JNK signaling pathways by up-regulating MKP1 expression, reduced apoptosis and the inflammatory reaction, and exerted a neuroprotective effect following cerebral ischemia/reperfusion injury.

Impact of Pitx3 gene knockdown on glial cell line-derived neurotrophic factor transcriptional activity in dopaminergic neurons

Pitx3 is strongly associated with the phenotype, differentiation, and survival of dopaminergic neurons. The relationship between Pitx3 and glial cell line-derived neurotrophic factor（GDNF） in dopaminergic neurons remains poorly understood. The present investigation sought to construct and screen a lentivirus expression plasmid carrying a rat Pitx3 short hairpin（sh）RNA and to assess the impact of Pitx3 gene knockdown on GDNF transcriptional activity in MES23.5 dopaminergic neurons. Three pairs of interference sequences were designed and separately ligated into GV102 expression vectors. These recombinant plasmids were transfected into MES23.5 cells and western blot assays were performed to detect Pitx3 protein expression. Finally, the most effective Pitx3 sh RNA and a dual-luciferase reporter gene plasmid carrying the GDNF promoter region（GDNF-luciferase） were cotransfected into MES23.5 cells. Sequencing showed that the synthesized sequences were identical to the three Pitx3 interference sequences. Inverted fluorescence microscopy revealed that the lentivirus expression plasmids carrying Pitx3-sh RNA had 40-50% transfection efficiency. Western blot assay confirmed that the corresponding Pitx3 of the third knockdown sequence had the lowest expression level. Dual-luciferase reporter gene results showed that the GDNF transcriptional activity in dopaminergic cells cotransfected with both plasmids was decreased compared with those transfected with GDNF-luciferase alone. Together, the results showed that the designed Pitx3-sh RNA interference sequence decreased Pitx3 protein expression, which decreased GDNF transcriptional activity.

Design of artificial small regulatory trans-RNA for gene knockdown in Bacillus subtilis

Bacillus subtilis as the Gram-positive model bacterium has been widely used in synthetic biology and biotechnology while the regulatory RNA tools for B.subtilis are still not fully explored.Here,a bottom-up approach is proposed for designing artificial trans-acting sRNAs.By engineering the intrinsic sRNA SR6,a minimized core scaffold structure consisting of an 8 bp stem,a 4 nt loop,and a 9 nt polyU tail was generated and proven to be sufficient for constructing sRNAs with strong repression activity(83%).Moreover,we demonstrate this artificial sRNA system functions well in an hfq-independent manner and also achieves strong repression efficiency in Escherichia coli(above 80%).A structure-based sRNA design principle was further developed for the automatic generation of custom sRNAs with this core scaffold but various sequences,which facilitates the manipulation and avoids structure disruption when fusing any base-pairing sequence.By applying these auto-designed sRNAs,we rapidly modified the cell morphology and biofilm formation,and regulated metabolic flux toward acetoin biosynthesis.This sRNA system with cross-species regulatory activities not only enriched the gene regulation toolkit in synthetic biology for B.subtilis and E.coli but also enhanced our understanding of trans-acting sRNAs.

敲减ARHGAP30基因对宫颈癌Siha细胞增殖及凋亡的影响

目的探究敲减Rho鸟苷三磷酸酶激活蛋白30(Rho GTPase-activating protein 30,ARHGAP30)后,宫颈癌Siha细胞增殖及凋亡的变化。方法设计特异性shARHGAP30引物并连接pLKO.1载体,转化到大肠杆菌感受态细胞中,再与慢病毒辅助质粒转入HEK-293T细胞,收集细胞上清获得的病毒过滤后感染Siha细胞,RT-qPCR和Western blot检测敲减效率,以及转染后Bax及Bcl-2的表达变化;CCK-8法检测敲减后细胞的增殖水平。结果成功构建敲减ARHGAP30基因的慢病毒质粒,并建立Siha稳转细胞,ARHGAP30在Siha细胞中的转录和翻译减少(P<0.01),Bax/Bcl-2明显降低(P<0.01),凋亡减少,细胞增殖水平升高(P<0.01)。结论ARHGAP30参与Siha细胞的增殖与凋亡,调控ARHGAP30基因或将干扰宫颈癌的发生和发展。

RNAi Mediated Silencing of Gene Encoding 1-Deoxy-D-Xylulose-5-Phosphate Reductoisomerase (DXR) in <i>Centella asiatica</i>

Centella asiatica (L.) is one of the most valuable medicinal plants since prehistoric times. The pharmaceutical importance of this herb is due to the accumulation of large quantities of pentacyclic triterpenoid saponins, collectively known as centelloids synthesized by the isoprenoid biosynthesis pathway. Biosynthesis of triterpenoid in the plants proceeds via either of the two pathways, viz. Mevalonate (MVA) pathway (in the cytosol) or 2-C-methyl-D-erythritol 4-phosphate (MEP) pathway (in plastid). In Centella, the pathway leading to the accumulation of triterpenoid is still not known or elucidated. Thus, to know whether the MVA or MEP pathway or a cross-talk between the pathway leads to the biosynthesis of triterpenoid, silencing the key regulatory gene using RNAi tool, of each of the pathway and then analyze a metabolite is an efficient approach. The key regulatory enzyme of the MVA pathway i.e. 3-Hydroxy-3-methylglutaryl-coenzyme A reductase (HMGR) has already been successfully silenced using RNAi tool [1]. In the present study, the 1-deoxy-D-xylulose-5-phosphate reductoisomerase (DXR) a key regulatory enzyme in MEP pathway is silenced. The RNAi-DXR construct in pHANNIBAL vector was cloned into a binary vector pART27 and subsequently transformed into Agrobacterium strain AGL1. The transient analysis of the RNAi-CaDXR using semi-quantitative RT-PCR confirmed the silencing of the endogenous DXR gene in Nicotiana and further confirmed in Centella asiatica. The present study is the first step aimed to delineate the MEP pathway using RNAi silencing approach to elucidate its role in the accumulation of triterpenoid in this important medicinal plant.

Cell-type specific and non-redundant anti-proliferative effects of shRNA-mediated Galpha12- and Galpha13 knockdown in lung cancer cell lines

In small cell lung cancer cells, various autocrine stimuli lead to the parallel activation of Gq/11 and G12/13 proteins. The contribution of the Gq/11-PLC-β cascade to the mitogenic effects in SCLC cells is well established, but the relevance of G12/13 signaling is less explored. While in prostate and breast cancer, G12/13 activation has been shown previously to promote invasiveness without being involved in cellular proliferation, previous data from our group indicate anti-proliferative effects of G12/13 knockdown in small cell lung cancer (SCLC) cells. To further investigate the role of G12/13-dependent signaling in lung tumor cells, we employed shRNA-mediated targeting of Gα12, Gα13, or both, in SCLC and NSCLC cell lines. Lentiviral expression of shRNAs resulted in specific Gα12 and Gα13 knockdown. Of note, upon single knockdown of one family member, no counter-upregulation of the other one was observed. Interestingly, inhibition of proliferation was cell line dependent. In cell lines where knock-down led to antiproliferation, single knockdown of either Gα12 or Gα13 was sufficient to impair proliferation and double knockdown of Gα12 and Gα13 tended not to further increase anti-proliferative effects. Likewise, when single knockdown was insufficient for an inhibition of proliferation, no effects were observed in double knockdowns. Taken together, these findings indicate that both Gα12 and Gα13 affect cellular proliferation individually and interference with one family member is sufficient for anti-tumor effects.

The emerging potential of siRNA nanotherapeutics in treatment of arthritis

RNA interference(RNAi)using small interfering RNA(siRNA)has shown potential as a therapeutic option for the treatment of arthritis by silencing specific genes.However,siRNA delivery faces several challenges,including stability,targeting,off-target effects,endosomal escape,immune response activation,intravascular degradation,and renal clearance.A variety of nanotherapeutics like lipidic nanoparticles,liposomes,polymeric nanoparticles,and solid lipid nanoparticles have been developed to improve siRNA cellular uptake,protect it from degradation,and enhance its therapeutic efficacy.Researchers are also investigating chemical modifications and bioconjugation to reduce its immunogenicity.This review discusses the potential of siRNA nanotherapeutics as a therapeutic option for various immune-mediated diseases,including rheumatoid arthritis,osteoarthritis,etc.siRNA nanotherapeutics have shown an upsurge of interest and the future looks promising for such interdisciplinary approach-based modalities that combine the principles of molecular biology,nanotechnology,and formulation sciences.

A molecular, phylogenetic and functional study of the <i>dADAR</i>mRNA truncated isoform during <i>Drosophila</i>embryonic development reveals an editing-independent function

Adenosine Deaminases Acting on RNA (ADARs) have been studied in many animal phyla, where they have been shown to deaminate specific adenosines into inosines in duplex mRNA regions. In Drosophila, two isoform classes are encoded, designated full-length (contains the editase domain) and truncated (lacks this domain). Much is known about the full-length isoform, which plays a major role in regulating functions of voltage-gated ion channel proteins in the adult brain. In contrast, almost nothing is known about the functional significance of the truncated isoform. In situ hybridization shows that both isoform mRNA classes are maternally derived and transcripts for both localize primarily to the developing central nervous system. Quantitative RT-PCR shows that about 35% of all dADAR mRNA transcripts belong to the truncated class in embryos. 3’-RACE results show that abundance of the truncated isoform class is developmentally regulated, with a longer transcript appearing after the mid-blastula transition.3’-UTR sequences for the truncated isoform have been determined from diverse Drosophila species and important regulatory regions including stop codons have been mapped. Western analysis shows that both mRNA isoform classes are translated into protein during embryonic development, as full-length variant levels gradually diminish. The truncated protein isoform is present in every Drosophila species studied, extending over a period spanning about 40 x 106 years, implying a conserved function. Previous work has shown that a dADAR protein isoform binds to the evolutionarily conserved rnp-4f pre-mRNA stem-loop located in the 5’-UTR to regulate splicing, while no RNA editing was observed, suggesting the hypothesis that it is the non-catalytic truncated isoform which regulates splicing. To test this hypothesis, we have utilized RNAi technology, the results of which support the hypothesis. These results demonstrate a novel, non-catalytic function for the truncated dADAR protein isoform in Drosophila embryonic development, which is very likely evolutionarily conserved.

转录因子NbNAC062及其纳米药物对PVY侵染的抑制作用

前期研究表明NbNAC062能够抑制PVY早期侵染,本研究通过构建NbNAC062敲除突变体和过表达植株进一步明确NbNAC062的抗病毒功能,并利用异硫氰酸荧光素(fluorescein-5-isothiocyanate,FITC)标记的壳聚糖季铵盐(chitosan quaternary ammonium salt,HACC)包被NbNAC062质粒,制备HACC-NbNAC062纳米药物。激光共聚焦显微镜对纳米药物进行示踪;透射电镜和激光粒子分析仪对其表征进行分析。通过GFP荧光差异、qRT-PCR和蛋白免疫印迹检测病毒含量来探明纳米药物对PVY侵染的影响。结果显示,敲除组病毒GFP荧光增强,而过表达组病毒GFP荧光减弱,PVY CP含量与上述结果一致。纳米药物粒径集中分布在18~32 nm之间;Zeta电位为+41.8 mV。浸润纳米药物HACC-NbNAC062后48 h,在细胞内观察到FITC-HACC(绿色荧光)与RFP-NbNAC062(红色荧光);接种PVY-GFP后5、7、9 d,NbNAC062-HACC施药组的PVY CP mRNA水平较对照组分别下调17.41%、47.81%、13.03%;第7天施药组PVY CP蛋白水平明显低于对照组,病毒荧光强度显著暗于对照组。上述研究结果说明HACC-NbNAC062纳米药物成功递送了NbNAC062,并发挥了其对PVY初期侵染的抑制作用。

中华绒螯蟹Scarb1基因功能及其与生长性状的关联分析

为研究B类Ⅰ型清道夫受体(SCARB1/SR-BI)在中华绒螯蟹代谢、生长以及免疫等生物学过程中的分子功能,实验对中华绒螯蟹Scarb1的克隆及时空表达进行了分析,观察了RNA干扰该基因后的相关组织结构和类胡萝卜素含量变化,筛选了该基因的SNP标记并与生长相关性状进行关联分析。结果显示,中华绒螯蟹的Scarb1由2个外显子和1个内含子组成,开放阅读框为2415 bp,编码805个氨基酸;系统进化分析显示中华绒螯蟹与三疣梭子蟹的氨基酸同源性高达80.51%,具有较高的物种间保守性。该基因在不同蜕壳时期的肝胰腺、肠道、血淋巴细胞、心脏、鳃和肌肉组织中均有表达,但在肝胰腺、肠道和血淋巴细胞中的表达量相对较高。RNA干扰Scarb1后,组织切片观察发现肝胰腺的肝小管管腔模糊并产生了部分空泡化结构,肠道内膜的肌肉层和黏膜下层处出现显著空洞现象;肝胰腺的颜色由黄色变成灰白色,其中的类胡萝卜素含量显著下降。在该基因的第一外显子筛选到1个SNP位点(C432T)与蜕壳后体重和壳长增长率存在显著相关性。本研究结果为Scarb1在中华绒螯蟹的遗传研究和育种应用提供参考。

载Cas9-RNP细胞膜囊泡仿生纳米粒的制备及其对小鼠巨噬细胞NLRP3基因的敲低作用

目的通过使用小鼠巨噬细胞膜包裹Cas9核糖核蛋白复合物(RNP),制备Cas9-RNP仿生纳米粒Cas9-RNP@MMs,旨在利用此仿生纳米粒递送Cas9-RNP复合物用于基因编辑,并进一步在体外研究小鼠巨噬细胞RAW264.7对Cas9-RNP@MMs的内吞情况及其基因编辑效果,为开发低毒性的抑制NLRP3治疗靶点的仿生纳米粒载体提供证据。方法将提取的小鼠巨噬细胞细胞膜与制备的Cas9-RNP混合,超声后使用脂质体挤压仪挤压得到Cas9-RNP@MMs。使用纳米颗粒跟踪仪检测Cas9-RNP@MMs的颗粒直径,透射电子显微镜下观察Cas9-RNP@MMs的颗粒形态。激光共聚焦荧光显微镜成像分析细胞对Cas9-RNP@MMs的内吞情况。采用MTT法检测Cas9-RNP@MMs生物相容性。通过qPCR和Western blot检测NLRP3表达,来验证Cas9-RNP@MMs敲低NLRP3基因的效果。结果采用巨噬细胞细胞膜制备的Cas9-RNP@MMs平均粒径约为216 nm;激光共聚焦荧光显微镜下,Cas9-RNP@MMs能成功被RAW246.7细胞摄取;MTT检测结果显示Cas9-RNP@MMs处理的小鼠巨噬细胞RAW246.7具有良好的生物相容性;qPCR和Western blot检测显示,有两条NLRP3特异的向导RNA(sgRNA)通过Cas9-RNP@MMs介导,有良好的敲低NLRP3基因表达的效果。结论利用仿生纳米粒成功制备了内腔载有Cas9-RNP复合物的纳米级囊泡Cas9-RNP@MMs,Cas9-RNP@MMs具有良好的生物相容性并且可以被RAW246.7细胞高效内吞;含有NLRP3特异的sgRNA的Cas9-RNP@MMs能够特异性敲低NLRP3基因表达。

一种肺血管基因敲减动物模型的构建及在肺动脉高压中的运用

目的 探讨经大鼠的气道注入1型腺相关病毒(AAV1)携带的KLF4-shRNA能否有效构建肺血管基因敲减动物模型以及其在肺动脉高压中的运用。方法 根据大鼠KLF4基因序列,设计针对大鼠特异性的siRNA序列,并以细胞计数和细胞迁移实验加以验证,然后进一步构建AAV1-KLF4-shRNA腺相关病毒载体。将44只清洁级SD大鼠随机分为4组:健康对照组、盐水模型组、对照病毒载体组、基因敲减组。后3组大鼠分别气管内注入生理盐水(盐水模型组)、AAV1-control vector(对照病毒载体组)、AAV1-KLF4-shRNA(基因敲减组)。1个月后对后3组进行烟熏造模,烟熏4个月后麻醉各组大鼠,分别检测右心室收缩压和平均右心室压,并取肺组织以免疫荧光法观察病毒载体在肺血管中的表达情况,通过PCR方法测定肺动脉中KLF4水平,通过HE染色比较肺小血管中膜厚度评估肺血管肥厚程度。取大鼠心脏计算右心肥厚指数。结果 细胞计数和细胞迁移实验证实选用的KLF4-siRNA链有效。免疫荧光实验显示,经大鼠气道注入的1型腺相关病毒载体均沿肺血管分布。荧光定量PCR实验显示,基因敲减(AAV1-KLF4-shRNA)组大鼠肺小动脉中KLF4的mRNA表达量明显低于其他两组。血流动力学检测结果显示,盐水模型组及对照病毒载体组的右心室收缩压和平均右心室压均明显高于健康对照组,而接受肺血管KLF4基因敲减的大鼠的右心室收缩压和平均右心室压均明显低于盐水模型组及对照病毒载体组。HE染色及右心肥厚指数结果显示,盐水模型组及对照病毒载体组的肺小血管重构及心室重构程度明显高于健康对照组,而接受肺血管KLF4基因敲减的大鼠的肺小血管重构及心室重构程度明显低于盐水模型组及对照病毒载体组。结论 肺血管特异性KLF4基因敲减模型构建成功并成功地在肺动脉高压中发挥作用,为进一步深入研究肺动脉高压的发病机制提供了平台和实验基础。

小鼠shRNA-Slfn3重组腺病毒载体的构建及其在EPCs中转染效率的测定

目的构建小鼠短发夹RNA(shRNA)-Schlafen3(Slfn3)重组腺病毒载体,并检测其在内皮祖细胞(EPCs)中的转染效率。方法采用GenBank基因软件查询小鼠Slfn3基因序列,设计并合成3个siRNA片段及其引物,取腺病毒干扰载体pADV-U6-shRNA-CMV-EGFP,采用限制性内切酶进行酶切,线性化后连接siRNA片段,获得重组腺病毒载体shRNA-Slfn3,从中筛选阳性克隆抽提质粒,进行DNA测序验证;取对数生长期的人胚胎肾细胞HEK293,采用Admax系统将目的质粒转染至HEK293细胞,获得重组腺病毒shRNA-Slfn3后进行小量扩增及病毒滴度测定;取小鼠脾脏单个核细胞体外培养至对数期EPCs,用前述所得重组腺病毒shRNA-Slfn3对其进行转染48 h,采用绿色荧光蛋白量检测重组腺病毒的转染效率。结果测序验证3组目的质粒构建成功;获得shRNA-Slfn3重组腺病毒,病毒滴度分别为2.37×10^(13)pfu/L、3.16×10^(13)pfu/L及4.74×10^(13)pfu/L;EPCs转染效率为(63.64±2.58)%。结论成功构建了小鼠shRNA-Slfn3重组腺病毒载体,转染小鼠脾源EPCs后的转染效率较高。

臭虫击倒抗性基因突变检测及抗性测定

近20多年,臭虫(Cimex spp.)在世界范围内成为常见的卫生害虫,其防治主要采用化学防治,但很多种群发现击倒抗性(Knockdown resistance gene,kdr)基因突变的存在以及抗药性。监测kdr的发生频率以及不同种群对农药的抗性对臭虫有效防治很重要,但我国对臭虫种群的抗药性报道很少。本试验采用点滴法测定了1个温带臭虫Cimex lectularius野外种群对氯虫苯甲酰胺、呋虫胺、吡虫啉、噻虫嗪和高效氯氰菊酯等5种药剂的毒性及抗性水平,使用区分剂量快速鉴定抗性方法对2个温带臭虫和2个热带臭虫Cimex hemipterus种群对高效氯氰菊酯的抗性水平进行了检测,此外用PCR方法检测8个臭虫地理种群(1个温带臭虫实验室种群,1个温带臭虫野外种群和6个热带臭虫野外种群)174个个体的kdr突变频率。点滴法结果表明,5种杀虫剂对温带臭虫的毒性是吡虫啉和呋虫胺>噻虫嗪>氯虫苯甲酰胺和高效氯氰菊酯,测试的野外温带臭虫种群仅对噻虫嗪无明显抗性。热带臭虫2个野外种群对高效氯氰菊酯的抗性均远高于温带臭虫。在温带臭虫的实验室种群中未检测到突变,在野外种群中检测到了V419L和L925I突变,可分为2种基因型类型(A:无突变位点;B:同时有L925I和V419L),而在热带臭虫的6个种群检测到M918I和L1014F突变,只有1种基因型类型,即M918I和L1014F双位点突变。温带臭虫1个野外种群及热带臭虫6个野外种群kdr突变的存在与臭虫对高效氯氰菊酯敏感密切关联。基于kdr基因突变检测结果推测我国臭虫种群广泛存在对拟除虫菊酯的抗性。

靶向敲减KLF4基因的重组腺相关病毒载体的构建及其在肺动脉高压动物模型中的应用

目的构建靶向敲减KLF4基因的重组腺相关病毒载体,并应用于肺血管疾病,为后期研究肺血管KLF4基因敲减在肺动脉高压大鼠中的作用及相关分子机制奠定基础。方法根据大鼠KLF4基因序列,设计针对大鼠特异性的siRNA序列,以pHBAAV-U6-MCS-CMV-EGFP作为空白载体,通过酶切技术构建带有GFP荧光标记的KLF4干扰腺病毒载体pHBAAV-r-KLF4shRNA-GFP,行测序分析,并进行病毒扩增、纯化及滴度测定。本研究对长时间(3个月)接触香烟烟雾的大鼠进行气道注入AAV1-KLF4-shRNA的干预治疗,观察大鼠右心室收缩压、平均右心室压等血流动力学指标改变。结果经测序检测显示,大鼠AAV1-KLF4-shRNA腺相关病毒载体构建成功。健康对照组、生理盐水模型组、对照病毒模型组、治疗干预组的右心室收缩压和平均右心室压比较,差异均有统计学意义(P<0.05)。结论对长时间接触香烟烟雾的肺动脉高压模型大鼠应用AAV1-KLF4-shRNA腺相关病毒载体,能有效改善右心室收缩压和平均右心室压,该载体在相关疾病动物模型中应用有效,为后期顺利开展AAV1-KLF4-shRNA在肺动脉高压中的预防和治疗作用,以及相关分子机制的深入研究提供基础条件。

MC4R基因沉默对牛成纤维细胞内基因表达的影响

旨在研究黑素皮质激素4受体基因(Melanocortin-4receptor,MC4R)沉默对牛成纤维细胞内能量与脂肪代谢相关通路上基因表达的影响,进一步揭示MC4R基因与肉牛胴体品质以及能量平衡与脂肪代谢之间的关系。本试验使用MC4R被敲降的牛成纤维细胞系,借助深度测序技术寻找试验组(MC4R敲降)和阴性对照组(MC4R未敲降)中表达量差异显著的基因。利用GO注释聚类分析和KEGG通路富集分析对涉及能量代谢、脂肪运输及相关调控通路的差异基因进行了深入的富集分析。随机选取差异表达基因中的10个基因,利用实时定量PCR对深度测序结果进行验证。此外,本研究借助牛SNP芯片对上述目标基因的单核苷酸多态性(SNP)进行了检测,并对136头西门塔尔牛进行了基于目标基因各SNP的基因型检测。基于各SNP的分型数据,本研究进一步利用PLINK软件对SNP与牛各胴体性状的关联性进行分析。通过深度测序,在两组阳性MC4R被敲降的牛成纤维细胞系中共发现7 799个差异表达基因,其中上调基因1 703个,下调基因6 096个。显著性GO分类在两组不同干扰水平处理组间共选出与能量代谢调节、脂肪运输过程相关的差异表达基因265个,功能聚类分析进一步筛选出与能量代谢相关的基因29个。KEGG通路富集分析发现,与能量代谢、脂肪运输等过程相关的265个差异表达基因共涉及到40个不同的通路,其中与MC4R基因及能量代谢调控有密切关联的Leptin、AGRP、NPY和POMC等基因同属于脂联素信号通路。MC4R敲降引起该通路上22个基因的表达发生显著变化。实时定量PCR结果表明,所选择的10个基因(表达量上调基因:CFB、RSAD2、IFIT3、CHI3L1和BOLA-N;表达量下调基因:UPK1B、IER2、LASS3、TGFβ3和AXUD1)的mRNA表达水平与测序结果无显著差异,从而证实了深度测序数据的准确性和可重复性。此外,借助50K密度的牛SNP芯片,本研究共发现了16个SNPs位点,共涉及11个目标基因。SNPs与牛各胴体性状的关联分析结果表明,10号染色体上的TGFβ3对西门塔尔牛眼肌面积、胴体重、腰部肉厚、大腿肉厚和外脊重有显著影响(P<0.05),对眼肉重、里脊重有极显著影响(P<0.01);同样位于10号染色体的RHOJ基因对西门塔尔牛眼肌面积也有显著影响(P<0.05)。19号染色体上的KRT17基因和7号染色体上VCAN基因均显著影响西门塔尔牛肉剪切力(P<0.01,P<0.05)。1号染色体的MASP1基因对肉色有显著影响(P<0.05)。结果显示,MC4R基因沉默显著影响牛成纤维细胞内参与能量代谢、脂肪代谢和能量稳态平衡调控过程相关基因的表达,进一步证实了MC4R基因能调控肉牛能量平衡和脂肪代谢以及影响肉牛胴体品质。

Kir 4.1基因沉默对U-251细胞周期的影响

目的:针对人内向整流性钾离子通道(inwardly rectifying potassium channel protein,Kir)4.1基因构建si RNA干扰载体,探讨其对U-251细胞增殖、生长的影响,为临床治疗及开发新的抗肿瘤药物提供实验依据。方法:采用细胞培养、质粒转染、流式分选、RT-PCR、Western blot及流式细胞仪对构建的质粒进行鉴定并观察对照组和干扰组细胞周期的变化。结果:对DH5α中抽提的重组载体测序验证结果和插入序列一致;成功筛选出一个有效质粒;质粒转染U-251细胞后,细胞周期中的G2期细胞数量由19.39%降至1.5%,明显减少(P=0.018),S期细胞数量由36.32%升至51.22%,明显增多(P=0.027)。结论:成功构建针对人Kir 4.1基因的si RNA干扰载体;Kir 4.1干扰载体可能是通过抑制U-251细胞周期中的G2期,使U-251细胞的生长停滞在S期,从而达到干扰U-251细胞的增殖能力。

应用CRISPR/Cas9技术构建IL-15敲除的MGC-803胃癌细胞株

目的 :运用CRISPR/Cas9基因编辑技术,建立IL-15基因敲除的MGC-803胃癌细胞株。方法 :针对IL-15基因作用的功能域,设计了靶向IL-15基因Exon2的gRNA。构建PX458-gRNA重组质粒并转化感受态细胞Stbl3,筛选出重组子后进行测序,通过测序确认了所设计的gRNA的有效性。并进一步通过流式细胞分选以及ELISA法检测筛选出的MGC-803胃癌细胞株IL-15基因的表达水平。结果 :测序结果显示敲除质粒构建成功,与阴性对照组相比,转染PX458-IL-15-g RNA质粒组IL-15的表达水平明显低于阴性对照组,差异具有统计学意义(P<0.001)。结论:利用CRISPR-Cas9系统成功构建了IL-15基因敲除的MGC-803细胞,为后续研究IL-15在肿瘤中的作用机制和功能奠定了基础。

抑制NSCLC细胞株H1299中EIF5A2表达对肿瘤生长及转移的影响

目的研究真核翻译起始因子5A2(eukaryotic translation initiation factor 5A2,EIF5A2)在非小细胞肺癌(non-small cell lung cancer,NSCLC)细胞株H1299中的作用和潜在分子机制。方法采用EIF5A2干扰RNA,敲除NSCLC细胞株H1299中的EIF5A2后,评估细胞的增殖能力、细胞凋亡率、细胞迁移和侵袭能力;采用Western印迹法检测NSCLC细胞株H1299敲除EIF5A2后,肿瘤相关蛋白和E-cadherin的表达情况。结果 EIF5A2的表达在NSCLS细胞株H1299中上调。而在体外实验中,EIF5A2的沉默可以抑制肿瘤细胞生长并诱导凋亡,降低细胞的迁移和侵袭能力,上调c-Myc、Bcl-2、Rac1表达,下调E-cadherin的表达。结论 EIF5A2可以促进NSCLC细胞株H1299的增殖和转移,可能成为NSCLS药物作用新靶点。

硒蛋白x基因沉默和过氧化氢处理对人正常肝脏细胞中硒蛋白基因表达和抗氧化酶活性的影响

本试验旨在探讨硒蛋白x(Selx)基因沉默和过氧化氢(H2O2)处理对人正常肝脏细胞(LO2)中硒蛋白基因表达和抗氧化酶活性的影响,为探索Selx与其他硒蛋白之间的调控关系及Selx的功能奠定基础。对本实验室保存的Selx基因稳定沉默LO2细胞株(si Selx)和对照细胞株(CK),利用噻唑兰(MTT)法比较其生长速率;si Selx和CK用200μmol/L H2O2处理2.5 h后,采用荧光定量PCR技术考察25个硒蛋白基因的表达量;同时比较Selx基因沉默以及H2O2处理对LO2细胞株中谷胱甘肽过氧化物酶(GSH-Px)、超氧化物歧化酶(SOD)活性及总抗氧化能力(T-AOC)的影响。结果显示:1)Selx基因沉默显著降低了LO2细胞株的生长速率(P<0.05);2)Selx基因沉默显著上调了G px6、Txnrd2、Seli基因的表达量(P<0.05),显著下调了Dio2、Dio3、Selm、Sepw1基因的表达量(P<0.05);H2O2处理显著上调了Dio1基因的表达量(P<0.05),显著下调了G px2基因的表达量(P<0.05);Selx基因沉默后H2O2处理显著上调了G px6、Txnrd2、Dio1基因的表达量(P<0.05),显著下调了Txnrd3、Dio2、Selm、Sepw1、Selv基因的表达量(P<0.05);3)Selx基因沉默显著提高了LO2细胞株GSH-Px活性(P<0.05),显著提高了SOD的活性(P<0.05);Selx基因沉默后H2O2处理显著提高了GSH-Px活性(P<0.05)。由此可见,Selx基因沉默降低了LO2细胞株的生长速率,Selx基因沉默后H2O2处理影响部分硒蛋白基因在细胞中的表达量,同时也影响了GSH-Px、SOD活性。