miR-486-5p通过抑制端粒酶活性促进人骨髓间充质干细胞衰老

目的:研究年龄相关microRNA-486-5p(miR-486-5p)对人骨髓间充质干细胞(h MSCs)衰老的调控作用。方法:通过microRNA芯片和real-time PCR检测供体年龄对h MSCs中miR-486-5p表达的影响;通过转染miR-486-5p模拟物或抑制物,过表达miR-486-5p或抑制其表达;用β-半乳糖苷酶染色检测miR-486-5p对h MSCs衰老的影响;通过siRNA研究沉默信息调节因子1(SIRT1)对h MSCs端粒酶逆转录酶(TERT)、端粒酶活性及衰老的影响。结果:随供体年龄增加,h MSCs中miR-486-5p的表达增加。过表达miR-486-5p可促进h MSCs衰老。相反,抑制miR-486-5p的表达可减少h MSCs的衰老。SIRT1及TERT随供体年龄增加而表达下降,直接抑制SIRT1的表达可减少TERT表达,抑制端粒酶活性,促进细胞衰老。同时抑制miR-486-5p和SIRT1的表达,使miR-486-5p失去对h MSCs端粒酶活性及衰老的调控作用。结论:miR-486-5p通过抑制SIRT1,减少h MSCs端粒酶活性,促进h MSCs衰老。     

微小RNA-199a-5p通过靶向SIRT1促进心肌纤维化相关基因表达

目的:研究微小RNA-199a-5p(miR-199a-5p)对心肌成纤维细胞中纤维化相关基因表达的调控作用及其可能作用的靶基因。方法:原代分离并体外培养成体C57BL/6小鼠心肌成纤维细胞;双萤光素酶报告基因实验检测miR-199a-5p与潜在靶基因沉默信息调节因子1(SIRT1)3’端非翻译区(3’-UTR)的结合作用;实时荧光定量PCR(RT-q PCR)和Western blot法分别检测SIRT1以及纤维化标志物胶原蛋白(Col)1a1、Col3a1和α-平滑肌肌动蛋白(α-SMA)的mRNA和蛋白表达。结果:在血管紧张素Ⅱ(AngⅡ)诱导的小鼠心肌成纤维细胞中,Col1a1、Col3a1和α-SMA的表达增强,miR-199a-5p表达上调。在心肌成纤维细胞中过表达miR-199a-5p可以增强Col1a1、Col3a1和α-SMA的表达。双萤光素酶报告基因实验显示miR-199a-5p与SIRT1 3’-UTR有结合作用。RT-q PCR和Western blot结果证实miR-199a-5p可在转录水平抑制SIRT1表达。过表达miR-199a-5p和沉默SIRT1均能一致性促进心肌成纤维细胞中Col1a1、Col3a1和α-SMA的表达。抑制AngⅡ诱导的小鼠心肌成纤维细胞中NF-κB激活,可显著降低miR-199a-5p表达。结论:SIRT1是miR-199a-5p的作用靶基因,并介导miR-199a-5p促进纤维化标志物Col1a1、Col3a1和α-SMA的表达。     

miR-7-5p和miR-152-3p联合调控Wnt/β-catenin通路对乳腺癌细胞上皮-间质转化及化疗耐药的影响

目的探讨miR-7-5p和miR-152-3p协同抑制乳腺癌细胞上皮-间质转化(epithelial-mesenchymal transition, EMT)进程及紫杉醇耐药的分子机制。方法采用生物信息学软件预测miR-7-5p和miR-152-3p的靶基因,双荧光素酶报告基因检测两者与TCF4的靶向关系;Western blot法检测各组细胞中Wnt/β-catenin信号通路关键调控因子β-catenin及TCF4蛋白的表达;在转染miR-7-5p mimics和miR-152-3p mimics基础上给予Wnt/β-catenin通路激活剂LiCl处理后,Western blot法检测MCF-7/TAX细胞中β-catenin、TCF4和EMT相关蛋白(E-cadherin、vimentin)的表达,Transwell小室实验检测MCF-7/TAX细胞侵袭和迁移能力;MTT实验检测激活Wnt/β-catenin信号通路对MCF-7/TAX细胞紫杉醇耐药性的影响。结果 TCF4 3′UTR区域存在能够与miR-7-5p及miR-152-3p互补的结合位点;转染miR-7-5p mimics和miR-152-3p mimics后可使TCF4野生型(TCF4-WT)报告基因载体的荧光素酶活性较NC组明显降低(P0.05)。Western blot结果显示,与NC组相比,转染miR-7-5p mimics和miR-152-3p mimics后各组紫杉醇耐药MCF-7/TAX细胞中β-catenin和TCF4蛋白的表达水平明显降低(P0.05),且两者共同转染后MCF-7/TAX细胞中β-catenin和TCF4蛋白的表达水平较miR-7-5p组或miR-152-3p组进一步降低(P0.05)。Western blot结果显示,LiCl处理后MCF-7/TAX细胞中β-catenin、TCF4和vimentin蛋白表达水平明显升高,而E-cadherin蛋白表达水平明显降低(P0.05)。Transwell小室结果显示,LiCl处理后MCF-7/TAX细胞侵袭和迁移能力明显增强(P0.05)。MTT结果显示,不同浓度紫杉醇作用下,miR-7-5p+LiCl组细胞增殖活力较miR-7-5p组明显升高;同时miR-152-3p+LiCl组和miR-7-5p/152-3p+LiCl组细胞的增殖活力较NC组均明显升高(P0.05)。结论 TCF4是miR-7-5p和miR-152-3p的共同靶标。miR-7-5p和miR-152-3p可共同抑制MCF-7/TAX细胞中Wnt/β-catenin信号通路的活化。     

miR-9-5p通过抑制SIRT1调控骨关节炎发病进程中软骨细胞的凋亡

为研究miR-9-5p靶向沉默信息调节因子2相关酶1(silent information regulator factor 2-related enzyme 1, SIRT1)对骨关节炎(osteoarthritis, OA)软骨细胞凋亡的影响及相关机制,对小鼠的原代软骨细胞进行分离、培养并构建OA细胞模型(加入IL-1β)和OA小鼠模型,检测miR-9-5p的表达、Caspase-3活性、细胞活性及凋亡。确定miR-9-5p和SIRT1存在靶向关系后检测SIRT1活性和上述指标。用番红O-固绿对OA小鼠组织进行染色并分析,在OA小鼠模型中再次验证miR-9-5p通过抑制SIRT1对软骨细胞凋亡的影响。结果显示,miR-9-5p mRNA在OA组织及IL-1β处理的软骨细胞中表达显著升高(P<0.001), miR-9-5p可抑制OA软骨细胞活性(P<0.001)并促进其凋亡(P<0.01)。miR-9-5p靶向作用于SIRT1,并通过抑制SIRT1抑制OA软骨细胞活性(P<0.001),促进其凋亡(P<0.05)。在OA动物模型的验证中得到相同的结果。...     

miR-98-5p通过降低STAT3水平促进A549细胞凋亡并抑制其侵袭和迁移

目的研究微小RNA-98-5p (miR-98-5p)对肺癌A549细胞生长的影响及机制。方法实时定量PCR检测正常支气管上皮细胞HBE细胞和非小细胞肺癌来源的细胞(A549细胞、H1299细胞和H460细胞)中miR-98-5p的水平,后续选择miR-98-5p水平最低的A549细胞进行实验。CCK-8法检测miR-98-5p模拟物(miR-98-5p mimic)及miR-98-5p抑制物(anti-miR-98-5p)对A549细胞增殖的影响,流式细胞术检测miR-98-5p对A549细胞的凋亡的影响,商品化试剂盒检测胱天蛋白酶3(caspase-3)和caspase-9的活性,TranswellTM小室实验检测miR-98-5p对A549细胞侵袭和迁移的影响,实时定量PCR检测miR-98-5p对A549细胞信号转导子与转录激活子3(STAT3) mRNA水平的影响,Western blot法检测miR-98-5p对A549细胞STAT3蛋白水平的影响。结果与HBE细胞相比,A549细胞、H1299细胞和H460细胞中miR-98-5p的表达水平降低。上调A549细胞miR-98-5p水平后,能够显著抑制A549细胞的增殖、促进细胞凋亡,并抑制细胞侵袭和迁移,同时,miR-98-5p可以显著降低STAT3的表达。结论 miR-98-5p通过降低STAT3水平促进A549细胞凋亡,并抑制其增殖、侵袭和迁移。     

微小RNA-98-5p靶向Kruppel样转录因子9对大鼠心肌缺血再灌注损伤的保护作用

目的 探讨微小RNA（miR)-98-5p靶向Kruppel样转录因子9(KLF9)对大鼠心肌缺血/再灌注（MI/R）损伤的保护作用。 方法 50只大鼠随机分为假手术组、模型组、miR-98-5p agomir组、agomir-NC组及miR-98-5p agomir+pcDNA-3. 1-KLF9组,每组10只。通过冠状动脉结扎法建立MI/R注模型。HE染色观察心肌组织病理情况;TUNEL检测心肌组织细胞凋亡情况;ELISA检测血清肌酸激酶(CK)、肌酸激酶同工酶(CK-MB)、乳酸脱氢酶(LDH)含量;Real-time PCR检测心肌组织miR-98-5p、KLF9 mRNA表达水平;Western blotting检测心肌组织KLF9、Bax和JAK2/STAT3信号通路相关蛋白表达;双荧光素酶报告实验验证miR-98-5p与KLF9的关系。 结果 与假手术组相比,模型组大鼠心肌细胞排列较乱,出现坏死;心肌组织细胞凋亡率、血清CK、CK-MB、LDH含量均升高,心肌组织miR-98-5p表达水平下降,KLF9 mRNA和蛋白及p-JAK2和p-STAT3蛋白表达均升高（P<0.05）。过表达miR-98-5p后,大鼠心肌细胞排列较为整齐,心肌细胞坏死减少;心肌组织细胞凋亡率、血清CK、CK-MB、LDH含量及心肌组织p-JAK2、p-STAT3蛋白表达均下降（P＜0.05）。双荧光素酶报告实验结果验证KLF9是miR-98-5p的靶基因。过表达KLF9逆转了miR-98-5p agomir对心肌损伤大鼠产生的作用。 结论 MiR-98-5p靶向KLF9改善MI/R大鼠心肌损伤,其机制可能与miR-98-5p调控JAK2/STAT3信号通路抑制心肌细胞凋亡相关。     

miR-150-5p靶向SIRT1提高肝癌细胞系HepG2放疗敏感性

目的探究miR-150-5p靶向SIRT1提高肝癌细胞放射敏感性的作用机制。方法用分次放疗放射递增法诱导建立放射抵抗型细胞株(RR-HepG2);RT-qPCR检测HepG2和RR-HepG2在不同放射剂量下miR-150-5p的表达水平;细胞克隆实验检测相同放射剂量下两种细胞的放疗敏感性;流式细胞计量术和Western blot检测过表达miR-150-5p对HepG2凋亡的影响;双荧光素酶报告基因法检测miR-150-5p与SIRT1的关联;细胞克隆实验和Western blot检测过表达SIRT1后,细胞的放疗敏感性和凋亡蛋白的变化。结果与亲代HepG2比较,相同放射剂量下,RRHepG2组miR-150-5p的表达量均显著降低(P<0. 05);放射处理后,与control、agomiR-NC组比较,agomiR-150-5p组的细胞存活分数显著降低,敏感性高(P<0. 05),Bax、caspase-9蛋白表达水平显著升高,Bcl-2蛋白表达水平显著降低,细胞凋亡率显著升高;双荧光素酶报告基因法验证miR-150-5p靶向调控SIRT1。与agomiR-NC组比较,野生型(WT) agomiR-150-5p荧光素酶活性显著降低,SIRT1蛋白水平显著降低(P<0. 05);与anta-agomiR-NC比较,野生型(WT) anta-agomiR-150-5p荧光素酶活性显著升高,SIRT1蛋白水平显著升高(P<0. 05);放射处理后,与agomiR-NC组比较,agomiR-150-5p组的细胞存活分数显著降低,Bax、caspase-9蛋白表达水平显著升高,Bcl-2蛋白表达水平显著降低(P<0. 05);与agomiR-150-5p+vector组比较,agomiR-150-5p+SIRT1组的细胞存活分数显著升高,Bax、caspase-9蛋白表达水平显著降低,Bcl-2蛋白表达水平显著升高(P<0. 05)。结论 miR-150-5p靶向SIRT1,下调其表达,提高肝癌细胞放射敏感性,可为临床肝癌放射治疗增敏提供靶点。     

白头翁皂苷A通过调控miR-24-3p/RNF2的表达影响乳腺癌细胞增殖及放射敏感性

目的:探讨白头翁皂苷A对乳腺癌细胞增殖及放射敏感性的影响及其作用机制。方法:用浓度为0、5、10、15和20 mg/L的白头翁皂苷A作用于人乳腺癌MCF-7细胞,并转染微小RNA-24-3p(miR-24-3p)过表达载体或抑制表达载体。用MTT法检测细胞活力的变化;集落形成实验检测细胞放射敏感性;RT-qPCR分析miR-24-3p和环指蛋白2(RNF2)的mRNA表达水平;Western blot检测RNF2的蛋白表达;萤光素酶报告基因实验检测miR-24-3p和RNF2的靶向关系。结果:与对照组(0 mg/L)相比,5、10、15和20 mg/L的白头翁皂苷A组MCF-7细胞的增殖抑制率显著升高(P<0.05),白头翁皂苷A处理的MCF-7细胞经射线照射后存活分数显著降低,RNF2表达水平显著降低(P<0.05);miR-24-3p靶向负调控RNF2。白头翁皂苷A和miR-24-3p同时处理的MCF-7细胞经射线照射后,存活曲线下移;抑制miR-24-3p表达可逆转白头翁皂苷A对MCF-7细胞的增殖抑制和放射增敏作用。结论:白头翁皂苷A可能通过miR-24-3p/RNF2影响乳腺癌细胞的增殖和放射敏感性。     

miR-7-5p靶向丝氨酸/苏氨酸激酶11调控非小细胞肺癌细胞A549的凋亡

目的探讨miR-7-5p是否靶向丝氨酸/苏氨酸激酶11(LKB1)调控非小细胞肺癌细胞A549的凋亡。方法通过TargetScanHuman分析miR-7-5p与LKB1的匹配情况,然后通过荧光素酶报告系统检测miR-7-5p是否靶向LBK1;miR-7-5p mimics过表达或者miR-7-5p inhibitor敲低miR-7-5p的情况下,通过免疫印迹检测凋亡相关蛋白质Cleaved-caspase3和Bax的表达量,AMPK的总蛋白和是p-AMPK的表达量;通过Annexin-V染色检测非小细胞肺癌细胞A549的细胞凋亡水平。结果 miR-7-5p靶向LKB1的3′UTR;过表达miR-7-5p后,LKB1的表达量下降(P0.05),凋亡相关蛋白质Cleaved-caspase3和Bax的表达量上升(P0.05),p-AMPK的表达量减少(P0.05),非小细胞肺癌细胞A549的凋亡水平上升(P0.05),但是此种效应能被AMPK的抑制剂BML-275抑制;敲低miR-7-5p后,LKB1的表达量下降(P0.05),凋亡相关蛋白质Cleaved-caspase3和Bax的表达量下降(P0.05),p-AMPK的表达量上升(P0.05),非小细胞肺癌细胞A549的凋亡水平下降(P0.05)。结论 miR-7-5p通过靶向LKB1的3′UTR通过AMPK通路促进非小细胞肺癌细胞A549的细胞凋亡。     

miR-483-5p通过上调IGF2基因转录促进肝癌细胞生长、迁移与侵袭

目的:探讨miR-483-5p对人胰岛素样生长因子2(IGF2)基因P3启动子驱动的m RNA(P3 m RNA)表达的影响及其在肝细胞癌发生发展中的作用。方法:(1)采用real-time PCR检测人肝癌细胞株Huh7、Hep3B、Bel-7402、Hep G2和SMMC-7721,人正常肝细胞株HL-7702,83例人肝细胞癌组织和配对的癌旁组织,22例正常肝组织中miR-483-5p和P3 m RNA的表达水平,并应用Pearson相关分析评估P3 m RNA与miR-483-5p表达水平之间的关系。(2)将IGF2基因P3 m RNA的5’端非翻译区(5’UTR)克隆入p GL3启动子载体,构建P3 m RNA 5’UTR野生型(p GL3-P3-5’UTR-WT)及P3 m RNA 5’UTR突变型(p GL3-P3-5’UTR-MUT)重组萤光素酶报告质粒,将其分别与miR-483-5p mimic、miR-483-5p inhibitor及scrambled control共转染He La、293T及Huh7细胞,采用双萤光素酶报告系统检测萤光素酶活性。(3)分别将miR-483-5p mimic、miR-483-5p inhibitor及scrambled control转染Huh7及Hep3B肝癌细胞,应用real-time PCR检测这2种肝癌细胞P3 m RNA表达水平的变化。(4)应用real-time PCR检测肝癌细胞Huh7及Hep3B的细胞核和细胞质中miR-483-5p的表达水平;应用核连缀实验(nuclear run-on assay)分析miR-483-5p对P3 m RNA转录的影响;应用RNA稳定性实验分析miR-483-5p对P3 m RNA稳定性影响。(5)应用体外细胞功能实验研究miR-483-5p对Huh7肝癌细胞生长、凋亡、迁移与侵袭能力的影响。结果:(1)5种肝癌细胞株miR-483-5p及P3 m RNA表达水平均明显高于正常肝细胞株HL-7702(P0.01),肝细胞癌组织中miR-483-5p及P3 m RNA表达水平均明显高于配对的癌旁组织及正常肝组织(P0.01);线性相关分析显示,在5种肝癌细胞株及肝细胞癌组织中,P3 m RNA表达水平均与miR-483-5p水平呈正相关。(2)萤光素酶实验显示,miR-483-5p与P3m RNA 5’UTR的同源位点互补结合可促进P3 m RNA的表达。(3)瞬时转染实验显示,过表达miR-483-5p呈剂量依赖性促进Hep3B和Huh7肝癌细胞P3 m RNA表达水平的增高。(4)miR-483-5p表达实验显示,成熟miR-483-5p存在于肝癌细胞Hep3B和Huh7的细胞质和细胞核中;核连缀实验显示,miR-483-5p诱导Huh7肝癌细胞核中新生P3 m RNA转录;RNA稳定性实验表明,miR-483-5p不改变Huh7肝癌细胞P3 m RNA稳定性。(5)体外细胞功能实验显示,miR-483-5p促进Huh7肝癌细胞增殖,抑制其凋亡,并增强迁移与侵袭能力。结论:miR-483-5p高表达可部分通过上调IGF2基因P3 m RNA转录促进肝癌细胞生长、迁移与侵袭,进而参与肝细胞癌发生。     

Heterotypic interference between influenza viruses A/Aichi/2/68 and B/Massachusetts/1/71.

Virus particles produced by MDCK cells mixedly infected with 3 PFU/cell each of A/Aichi/2/68 (H3N2) (Aichi) and B/Massachusetts/1/71 (Mass) influenza viruses exclusively possessed haemagglutinin (HA) of Mass, although approximately one-fifth of the mixed yield had coding potential for Aichi serotype. Synthesis of major viral proteins of Aichi was markedly suppressed by co-infecting Mass. By increasing the multiplicity of co-infecting Aichi to 30 PFU/cell, interference became reciprocal. Aichi interfered with replication of Mass more severely than Mass did with replication of Aichi. All the major viral proteins of both Aichi and Mass were expressed within the infected cells.     

Associations Between G/A1229, A/G3944, T/C30875, C/T48200 and C/T65013 Genotypes and Haplotypes in the Vitamin D Receptor Gene, Ultraviolet Radiation and Susceptibility to Prostate Cancer

Ultraviolet radiation (UVR) may protect against prostate cancer via a mechanism involving vitamin D. Thus, the vitamin D receptor (VDR) gene is a susceptibility candidate, though published data are discrepant. We studied the association of prostate cancer risk with five VDR single nucleotide polymorphisms (SNPs): G/A¹²²⁹ (SNP 1), A/G³⁹⁴⁴ (SNP 2), T/C³⁰⁸⁷⁵ (SNP 3), C/T⁴⁸²⁰⁰ (SNP 4) and C/T⁶⁵⁰¹³ (SNP 5), in 430 cancer and 310 benign prostatic hypertrophy (BPH) patients. The SNP 2 GG genotype frequency was lower in cancer than BPH patients (odds ratio = 0.63, 95% CI = 0.41–0.98, p = 0.039). SNPs 1 and 2, and SNPs 4 and 5, were in linkage disequilibrium. Two copies of haplotypes comprising SNPs 1‐2, G‐G (odds ratio = 0.63, p = 0.039), SNPs 2‐3 G‐C (odds ratio = 0.45, p = 0.008) and SNPs 1‐2‐3 G‐G‐C (odds ratio = 0.44, p = 0.006), but not SNPs 1‐3, G‐C (odds ratio = 0.81, p = 0.34), were associated with reduced risk (reference, no copies of the haplotypes) . These associations were observed after stratification of subjects by extent of UVR exposure. These data show that SNP 2 GG genotype mediates prostate cancer risk, complementing studies reporting this allele is protective in malignant melanoma pathogenesis. They further suggest that published associations of risk with SNP 1 may result from linkage disequilibrium with SNP 2.     

Pathogenicity of PMV-3/parakeet/Netherlands/449/75 for chickens

Infection of 1-day-old chicks with PMV-3/parakeet/Netherlands/449/75 (449) by intramuscular, intranasal or contact routes resulted in severe impairment of growth in all groups compared to uninfected control birds. In the group infected intramuscularly with 449 virus 16/22 birds died within 14 days of infection. No clinical signs were seen in 6-week-old chickens infected with 449 by intramuscular, intranasal or contact routes. One-day-old chicks infected with a large dose of NDV-B(1) and one-day-old chicks placed in contact with these birds also showed significant impairment of growth compared to uninfected controls.     

Immunogenic and isotype-specific responses to Russian and US cold-adapted influenza a vaccine donor strains A/Leningrad/134/17/57, A/Leningrad/134/47/57, and A/Ann Arbor/6/60 (H2N2) in mice

The immunogenicity of the Russian cold-adapted (ca) donor stains, A/Leningrad (Len)/134/17/57 and A/Leningrad/134/47/57, and the US strain A/Ann Arbor (AA)/6/60-ca, were compared in BALB/c mice with their respective wild-type parental viruses. Each ca donor strain was less immunogenic than its wild-type parent. The vaccinating dose, when administered twice, which prevented multiplication of a standard challenge of parental wild-type virus in 50% of mice (the 50% protective dose or PD(50)), was shown for A/Len/134/17/57-ca, A/Len/134/47/57-ca, and A/AA/6/60-ca to be 10(3.77), 10(4.32), and 10(4.70), respectively. These findings were extended by measuring the number of antibody secreting cells induced in the lungs and mediastinal lymph nodes of mice infected with the same ca donors using an ELISPOT assay. When each donor strain was administered twice at a dose of 100 PD(50) over a 3-week interval, the overall immunoglobulin isotype antibody secreting cell profiles were shown to be similar. However, A/Len/134/17/57-ca and A/Len/134/47/57-ca induced significantly higher total immunoglobulin responses in the lungs than A/AA/6/60-ca (P < 0.05). A/Len/134/17/57-ca also induced a significantly greater IgA response in the lungs than A/AA/6/60-ca (P < 0.05). These results suggest that A/Len/134/17/57-ca is a superior immunogen to A/Len/134/47/57-ca which in turn is more immunogenic than A/AA/6/60-ca.     

Recent H1N1 viruses (A/USSR/90/77, A/Fiji/15899/83, A/Firenze/13/83) replicate poorly in ferret bronchial epithelium

Summary Three recent wild-type H1N1 influenza virus isolates (A/USSR/90/77, A/Fiji/15899/83 and A/Firenze/13/83) replicated poorly in organ cultures of ferret bronchial tissue compared with the replication of an H3N2 wild-type virus (A/England/939/69). All four viruses replicated well in nasal turbinate tissue. Examination of one H1N1 virus (A/USSR/90/77)in vivo showed heavy infection in the upper respiratory tract of ferrets but little in the lower respiratory tract. These results raise the possibility that the mildness of human influenza arising from the H1N1 strains may be due to lack of capacity to attack the lower respiratory tract as well as the presence of antibody in previously exposed persons.With 1 Figure