miR-451对肾小球系膜细胞增殖的抑制作用及其机制

目的探讨微小RNA(microRNA,miRNA)-451对肾小球系膜细胞增殖的抑制作用及其机制。方法在Lipofectamine 2000介导下,将miR-451模拟物(miR-451 mimics)及mimics对照分别转染高糖培养的肾小球系膜细胞,另设高糖未转染组和低糖未转染组,实时荧光RT-PCR法检测各组细胞中miR-451的表达水平;MTT法检测miR-451对小鼠肾小球系膜细胞增殖的影响;Western blot法检测靶蛋白Ywhaz、p-p38 MAPK和p-MKK3的表达水平。结果 miR-451组细胞中miR-451的表达水平较mimics对照组明显升高(P<0.01);miR-451组第2、3、4天的细胞增殖能力明显低于高糖未转染组(P均<0.05),第3、4天明显低于mimics对照组(P均<0.05);与mimics对照组和高糖未转染组比较,miR-451组细胞中Ywhaz、p-p38 MAPK和p-MKK3的表达水平均明显下降(P均<0.05)。结论 miR-451可抑制Ywhaz蛋白的表达,降低p38 MAPK信号途径中p-p38 MAPK和p-MKK3蛋白的表达,从而降低高糖诱导的肾小球系膜的增殖。本实验为研究糖尿病肾病(diabetic nephropathy,DN)的发病机制提供了新的思路。     

RECK基因3′UTR荧光素酶报告基因载体的构建

目的构建RECK(reversion-inducing cysteine-rich protein with kazal motifs)基因mRNA 3′非编码区(3′-untranslated region,3′UTR)全长及两个截短片段的荧光素酶报告基因载体,以进一步研究microRNA对RECK基因的调控。方法以人乳腺癌细胞系MCF-7基因组DNA为模板,PCR扩增RECK基因mRNA的3′UTR全长及两个截短片段,利用双酶切将目的片段定向插入报告基因载体pGL3-Control中,将克隆载体转化大肠埃希菌DH5α感受态细胞进行扩增,采用菌落PCR、双酶切、测序鉴定重组子,双荧光报告基因检测其表达活性。结果重组载体中RECK3′UTR序列与GenBank序列比对一致且插入方向正确;3个重组载体分别命名为pGL3-RECK 3′UTR-1、pGL3-RECK3′UTR-2和pGL3-RECK 3′UTR-3,转染细胞后可表达荧光素酶基因。结论成功构建了RECK基因3′UTR全长及两个截短片段的荧光素酶报告基因载体,为进一步研究microRNA对靶基因RECK的调控奠定了基础。     

糖尿病肾病相关微小RNA对高糖下肾小球系膜细胞增殖的影响及其机制

目的探讨在高糖培养条件下,糖尿病肾病相关微小RNA(MicroRNA,miRNA)即miR-21对小鼠肾小球系膜细胞生长、增殖的影响,及miR-21高表达对PTEN/PI3K信号途径的影响。方法采用高糖培养的小鼠肾小球系膜细胞模拟糖尿病状态,在Lipofectamine2000介导下经miR-21真核表达质粒pGenesil-miR-21转染,G418筛选获得稳定表达细胞株。采用实时RT-PCR检测转染细胞miR-21的表达水平,MTT法检测细胞增殖,细胞免疫化学法和Western blot法检测PTEN/PI3K信号途径关键分子PTEN、phospho-Ak(tSer473)和PI3Kp85α蛋白的表达水平。结果筛选出的肾小球系膜细胞能稳定高表达miR-21;高表达的miR-21对细胞增殖能力有明显的抑制作用,且可显著下调PTEN的表达水平(P<0.05),同时上调phospho-Akt(Ser473)和PI3Kp85α的表达水平(P<0.05)。结论 miR-21可通过特异性靶向抑制PTEN蛋白的表达,提高phospho-Akt(Ser473)和PI3Kp85α蛋白的表达水平,以减缓肾小球系膜细胞增殖,可能为一个预防和治疗糖尿病肾病新型的潜在靶点。     

锌指蛋白转录抑制因子145′非翻译区内部核糖体进入位点的活性

目的检测锌指蛋白转录抑制因子14(positive regulatory domain zinc finger protein 14,PRDM14)5′非翻译区(5′untranslated region,5′UTR)内部核糖体进入位点(internal ribosome entry site,IRES)的活性。方法 PCR扩增PRDM14 5′UTR各截短序列的基因及全长基因,分别插入至双荧光素酶和红绿荧光报告基因中,构建重组质粒p RLPRDM14 S1-FL、p RL-PRDM14 S2-FL、p RL-PRDM14 S3-FL及p G-PRDM 14-R。将各重组质粒分别转染HEK293细胞,检测PRDM14 5′UTR IRES元件的活性、内部剪切位点和自身启动子的活性及影响IRES活性的序列。将重组质粒p RL-FL/5′UTR分别转染HCT-8/WT、Hep-2、Bel7402/WT和NIH3T3细胞,检测各细胞中PRDM14 5′UTR IRES元件的活性。结果 PRDM14 5′UTR具有内部核糖体进入位点元件活性;不具有内部剪切位点和自身启动子活性;PRDM14 5′UTR的活性激活中心位于25~60 nt,活性抑制中心位于60~95 nt;除NIH3T3细胞外,其他细胞均具有IRES活性。结论 PRDM14 5′UTR具有典型的IRES活性,为今后深入研究PRDM14表达的调控机制奠定了基础。     

小鼠微RNA miR-21真核表达质粒的构建及其在小鼠肾小球系膜细胞中的表达

目的构建小鼠微RNA miR-21真核表达质粒,并在小鼠肾小球系膜细胞中表达。方法人工合成小鼠miR-21基因序列,构建miR-21真核表达质粒pGenesil-miR-21。使用脂质体Lipofectamine2000转染小鼠肾小球系膜细胞后,G418筛选,获得稳定转染克隆,提取总RNA,通过实时荧光定量RT-PCR技术检测miR-21的表达。结果经酶切鉴定和测序证实,合成的miR-21基因序列完全正确,并已成功克隆到真核表达质粒pGenesil-1上。重组真核表达质粒转染小鼠肾小球系膜细胞后,筛选出的阳性克隆可稳定高表达miR-21。结论已成功构建miR-21真核表达质粒,并在小鼠肾小球系膜细胞中高效表达,为进一步探讨miR-21的生物学功能奠定了基础。     

靶向小鼠Tsc1和Tsc2基因的CRISPR/Cas9系统的构建及其打靶效力验证

目的 设计并构建靶向Tsc1和Tsc2基因的CRISPR/Cas9基因编辑系统，并在细胞水平验证基因编辑效力。方法针对小鼠Tsc1和Tsc2基因分别设计3个sgRNA导向序列，构建sgRNA表达载体，与Cas9表达质粒共转染小鼠N2a细胞，经药物筛选获得阳性细胞后，PCR扩增打靶位点的DNA片段，利用TA克隆测序验证打靶效率。结果 Tsc1基因Tsc1-M-sgRNA2、Tsc1-M-sgRNA3及Tsc2基因Tsc2-M-sgRNA1、Tsc2-M-sgRNA2、Tsc2-M-sgRNA3这5个靶点均发生基因编辑，编辑效率分别为40%、80%、30%、30%和20%。结论 成功构建了有编辑效力的靶向小鼠Tsc1和Tsc2基因的CRISPR-Cas9基因编辑系统。     

HIV-1中和抗体检测方法的建立

目的以荧光素酶作为报告基因,表达假病毒,建立快速、有效的HIV-1中和抗体检测方法。方法将HIV-1中国流行株B/C重组亚型和C亚型Envelope基因的真核表达质粒分别与带有荧光素酶报告基因的pNL4-3.Luc.R-E质粒共转染293T细胞,培养48h后收获含有假病毒的上清液,感染表达CD4受体和一个辅助受体CCR5的HOS细胞,培养72h后,裂解细胞,检测荧光素酶含量。结果HIV-1的B/C重组亚型和C亚型Envelope基因真核表达质粒分别与pNL4-3.Luc.R-E质粒共转染的293T细胞,均有HIV-1结构蛋白Gagpol和Env的表达,相对分子质量分别为55000和160000,用产生的假病毒感染HOS-CD4-CCR5/CXCR4细胞后,产生的荧光素酶含量明显高于对照组。结论已建立了瞬时转染检测HIV-1中和抗体的方法,为今后抗体样本及病毒样本的检测提供了参考。     

microRNA-143阻遏乳腺癌细胞免疫抑制的作用及其机制

目的探讨microRNA-143(miR-143)阻遏乳腺癌细胞免疫抑制的作用及其分子机制。方法采用MTT法检测乳腺细胞HBL-100和乳腺癌细胞MCF-7、MDA-MB-231、BT549补体依赖的细胞毒性(complement-dependent cytotoxicity,CDC);在脂质体介导下,将miR-143、miR-143对照物(scramble)和miR-143抑制剂(inhibitor)分别转染MCF-7细胞,将miR-143 scramble和miR-143 inhibitor分别转染HBL-100细胞,采用MTT法检测CDC,RT-PCR法检测细胞中补体调节蛋白CD46基因mRNA的转录水平,Western blot法检测CD46蛋白的表达水平。结果乳腺癌细胞MCF-7、MDA-MB-231、BT-549的A570值与正常乳腺细胞HBL-100相比,均明显升高(P<0.01);与miR-143 scramble转染的MCF-7细胞的A570值相比,miR-143转染组的A570值明显下降(P<0.001),与miR-143 scramble转染的HBL-100细胞的A570值相比,miR-143 inhibitor转染的HBL-100细胞的A570值明显上升(P<0.001);与HBL-100细胞相比,CD46蛋白在MCF-7、MDA-MB-231和BT-549细胞中表达均上调,且与抑制CDC的作用呈正相关;在HBL-100细胞中过表达miR-143 inhibitor能上调CD46蛋白的表达水平,而不影响CD46基因mRNA的转录水平;在MCF-7细胞中过表达miR-143能明显抑制CD46蛋白的表达水平。结论 CD46在乳腺癌细胞中的上调导致了癌细胞对CDC的抵抗作用,是产生免疫抑制的机制之一;miR-143通过抑制CD46蛋白的表达水平,使细胞对CDC的作用更为敏感,提高了补体系统对乳腺癌细胞的杀伤作用,降低了其免疫抑制能力。     

miR-628-3p靶向结合STK17B基因对卵巢癌进展的抑制作用

目的 分析miR-628-3p通过靶向丝氨酸/苏氨酸激酶17B(serine/threonine kinase 17B,STK17B)抑制卵巢癌（ovarian cancer,OV）增殖、迁移和侵袭的能力。方法 生物信息学分析miR-628-3p在OV组织中的表达水平及预后。分别将空载NC质粒（miR-NC）、miR-628-3p、miR-628-3p+STK17B转染至人OV细胞SKOV3和HO8910中,RT-qPCR法检测转染细胞中miR-628-3p表达水平;CCK-8法和克隆试验检测各组细胞增殖能力;划痕愈合试验检测各组细胞迁移能力;Transwell侵袭试验检测各组细胞侵袭能力。裸鼠成瘤试验检测瘤体质量及体积变化。Starbase数据库预测miR-628-3p靶基因,双荧光酶素报告试验进行验证。Western blot法测定各组细胞STK17B蛋白表达水平。结果miR-628-3p在OV组织中低表达,且患者无病生存期低。与miR-NC组相比,miR-628-3p组SKOV3和HO8910细胞中miR-628-3p表达均上调（t分别为7.789和7.862,P均<0.0...     

Hyperphosphorylation of Tau Due to the Interference of Protein Phosphatase Methylesterase-1 Overexpression by MiR-125b-5p in Melatonin Receptor Knockout Mice

Melatonin has been indicated to ameliorate tau hyperphosphorylation in the pathogenesis of tau diseases, but the role of melatonin-receptor signal transduction has not been clearly discovered. In this study, we found intensive tau hyperphosphorylation in melatonin receptor knockout mice. Bielschowsky silver staining showed ghostlike neurofibrillary tangles in melatonin receptor-2 knockout (MT2KO) as well as melatonin receptors-1 and -2 knockout (DKO) mice, and an argyrophilic substance was deposited in melatonin receptor-1 knockout (MT1KO) mice. Furthermore, we found significantly decreased activity of protein phosphatase 2A (PP2A) by Western blot and enzyme-linked immunosorbent assay (ELISA), which was partly due to the overexpression of protein phosphatase methylesterase-1 (PME-1), but not glycogen synthase kinase-3β (GSK-3β), cyclin-dependent kinase 5 (CDK5) or protein kinase B (Akt). Finally, we observed a significant increase in cyclic adenosine monophosphate (cAMP) and a decrease in miR-125b-5p levels in MT1KO, MT2KO and DKO mice. Using a luciferase reporter assay, we discovered that miR-125b-5p largely decreased the expression of firefly luciferase by interfering with the 3′UTR of PME-1. Furthermore, miR-125b-5p mimics significantly decreased the expression of PME-1, while miR-125b-5p inhibitor induced tau hyperphosphorylation. These results show that melatonin-receptor signal transduction plays an important role in tau hyperphosphorylation and tangle formation.     

胰岛素诱导基因-2启动子荧光素酶报告基因重组质粒的构建与鉴定

目的构建胰岛素诱导基因-2(Insulin induced gene-2,Insig-2)启动子荧光素酶报告基因重组质粒,并检测其转录活性。方法从人基因组DNA中扩增Insig-2基因转录起始位点上游1 389 bp的启动子片段,插入pGL3-basic质粒中,构建重组质粒pGL3-Insig-2,将其与内参质粒pRL-TK瞬时共转染HEK293、HepG2和3T3-L1细胞,采用双荧光素酶法检测Insig-2启动子活性。结果重组质粒pGL3-Insig-2经双酶切和DNA测序,证实构建正确;pGL3-Insig-2质粒在HEK293、HepG2和3T3-L1细胞中均具有启动子活性,分别为阴性对照组(pGL3-basic空载体)的28、40和214倍、阳性对照组(pGL3-SV40)的2.6、5.5和30倍,呈现出强启动子活性。结论成功构建了Insig-2基因启动子荧光素酶报告基因重组质粒,为后续Insig-2基因的深入研究奠定了基础。     

MiR-181a-5p Regulates NIS Expression in Papillary Thyroid Carcinoma

NIS is a potent iodide transporter encoded by the SLC5A5 gene. Its expression is reduced in papillary thyroid carcinoma (PTC). In this study we analyzed the impact of miR-181a-5p on NIS expression in the context of PTC. We used real-time PCR to analyze the expression of SLC5A5 and miR-181a-5p in 49 PTC/normal tissue pairs. Luciferase assays and mutagenesis were performed to confirm direct binding of miR-181a-5p to the 3′UTR of SLC5A5 and identify the binding site. The impact of modulation of miR-181a-5p using appropriate plasmids on endogenous NIS and radioactive iodine accumulation was verified. We confirmed downregulation of SLC5A5 and concomitant upregulation of miR-181a-5p in PTC. Broadly used algorithms did not predict the binding site of miR-181a-5p in 3′UTR of SLC5A5, but we identified and confirmed the binding site through mutagenesis using luciferase assays. In MCF7 and HEK293-flhNIS cell lines, transfection with mir-181a-expressing plasmid decreased endogenous SLC5A5, whereas silencing of miR-181a-5p increased it. We observed similar tendencies in protein expression and radioactive iodine accumulation. This study shows for the first time that miR-181a-5p directly regulates SLC5A5 expression in the context of PTC and may decrease efficacy of radioiodine treatment. Accordingly, miR-181a-5p may serve as an emerging target to enhance the efficacy of radioactive iodine therapy.     

Targeted Suppression of Chaperone-Mediated Autophagy by miR-320a Promotes α-Synuclein Aggregation

Chaperone-mediated autophagy (CMA) is involved in wild-type α-synuclein degradation in Parkinson’s disease (PD), and LAMP2A and Hsc 70 have recently been indicated to be deregulated by microRNAs. To recognize the regularory role of miR-320a in CMA and the possible role in α-synuclein degradation, in the present study, we examined the targeting and regulating role of miR-320 in Hsc 70 expression. We first constructed an α-synuclein-overexpressed human neuroblastoma cell line, SH-SY5Y-Syn(+), stably over-expressing wild-type α-synuclein and sensitive to an autophagy inhibitor, which exerted no effect on the expression of LAMP2A and Hsc 70. Then we evaluated the influence on the CMA by miR-320a in the SH-SY5Y-Syn(+) cells. It was shown that miR-320a mimics transfection of specifically targeted Hsc 70 and reduced its expression at both mRNA and protein levels, however, the other key CMA molecule, LAMP2A was not regulated by miR-320a. Further, the reduced Hsc 70 attenuated the α-synuclein degradation in the SH-SY5Y-Syn(+) cells, and induced a significantly high level of α-synuclein accumulation. In conclusion, we demonstrate that miR-320a specifically targeted the 3'' UTR of Hsc 70, decreased Hsc 70 expression at both protein and mRNA levels in α-synuclein-over-expressed SH-SY5Y cells, and resulted in significant α-synuclein intracellular accumulation. These results imply that miR-320a might be implicated in the α-synuclein aggravation in PD.