miR-1和miR-133a对大鼠肥大心肌细胞L-型钙通道Cavβ_2和α1C亚基的调控作用

目的研究miR-1和miR-133a在大鼠心肌细胞肥大中对L-型钙通道β2亚基(Cavβ2)和α1C亚基的调控作用。方法异丙肾上腺素(ISO)诱导大鼠心肌细胞肥大;在线数据库micro Cosm和Targetscan预测miR-1和miR-133a的靶基因;分别构建含有Cavβ23'UTR或α1C 3'UTR的重组质粒,与miR-1或miR-133a共转染HEK293细胞,验证Cavβ2亚基是miR-1的靶基因,α1C亚基是miR-133a的靶基因;用Western blot法检测心肌细胞内Cavβ2和α1C蛋白表达;用siRNA干扰Cavβ2和α1C表达,明确Cavβ2和α1C在心肌细胞肥大中的作用。结果 1)Cavβ2为miR-1的潜在靶基因,α1C为miR-133a的潜在靶基因。2)分别将miR-1和Cavβ23'UTR,miR-133a和α1C 3'UTR共转染HEK293细胞,荧光素酶荧光值均显著降低(P0.05,P0.01)。3)分别转染miR-1 mimic、miR-133a mimic上调miR-1、miR-133a的表达后,心肌细胞内Cavβ2和α1C蛋白表达均明显下降(P0.01,P0.05)。4)用RNAi下调Cavβ2和α1C表达可明显抑制心肌细胞表面积(P0.01),ANP和β-MHC mRNA表达增加(P0.05)。结论Cavβ2亚基是miR-1的靶基因,α1C亚基是miR-133a的靶基因。miR-1和miR-133a可能通过负性调控L-型钙通道Cavβ2和α1C蛋白表达,抑制心肌细胞肥大。     

miR-34a 通过靶向SIRT1 对MPP+ 诱导的帕金森病模型细胞凋亡和氧化应激损伤的影响

目的:探讨miR-34a通过靶向SIRT1对MPP~+诱导的帕金森病模型细胞凋亡和氧化应激损伤的影响。方法:以MPP~+处理SH-SY5Y细胞建立帕金森病细胞模型,MTT法检测细胞存活率,RT-PCR检测细胞中miR-34a和SIRT1 mRNA的表达,Western blot检测SIRT1蛋白的表达。脂质体介导转染miR-34a模拟物和miR-34a抑制剂,RT-PCR和Western blot检测miR-34a对SIRT1 mRNA和蛋白表达的影响。采用荧光素酶实验检测miR-34a与SIRT1的靶向关系。将miR-34a抑制剂和SIRT1干扰序列转染至SH-SY5Y细胞后,采用流式细胞仪和LDH、SOD、MDA试剂盒分别检测miR-34a低表达靶向SIRT1对MPP~+诱导的SH-SY5Y细胞凋亡和氧化应激损伤的影响。结果:与对照组相比,500μmol/L、1 000μmol/L和2 000μmol/L MPP~+能够降低SH-SY5Y细胞的存活率、上调miR-34a和下调SIRT1表达(P0.05),且呈浓度依赖性。miR-34a模拟物可引起SIRT1 mRNA和蛋白表达降低,miR-34a抑制剂可引起SIRT1 mRNA和蛋白表达升高;荧光素酶实验证实SIRT1是miR-34a的靶基因。2 000μmol/L MPP~+可诱导SH-SY5Y细胞凋亡,细胞上清液中MDA含量和LDH活性显著升高,而SOD活性降低;转染miR-34a抑制剂成功下调miR-34a表达后可逆转MPP~+引起的上述变化,而转染SIRT1干扰序列成功下调SIRT1表达后可减弱miR-34a低表达引起的上述变化。结论:miR-34a低表达可通过靶向调控SIRT1抑制MPP~+诱导的帕金森病模型细胞凋亡和氧化应激损伤。     

circNCX1通过miR-103-3p调节阿霉素诱导的心肌细胞凋亡

目的:探究环状RNA NCX1(circNCX1)对阿霉素(又称多柔比星,DOX)诱导的心肌细胞凋亡的调节作用。方法:通过RT-qPCR检测经DOX处理的H9c2细胞和注射DOX的小鼠心肌组织中circNCX1表达量的变化;TUNEL染色和凋亡相关蛋白caspase-3/-7的活性检测试剂盒检测细胞凋亡水平;台盼蓝染色检测细胞存活率;RNA pull-down实验验证circNCX1与其下游微小RNA-103-3p(miR-103-3p)的直接结合。结果:DOX诱导的H9c2细胞及小鼠心肌组织中circNCX1升高,并且DOX可诱导心肌细胞凋亡,表现为心肌细胞TUNEL阳性率及caspase-3/-7活性升高。抑制circNCX1表达能够显著减少DOX诱导的心肌细胞TUNEL阳性率,并且降低caspase-3/-7的活性。circNCX1通过直接结合miR-103-3p抑制其表达。此外,过表达miR-103-3p同样能够抑制DOX诱导的心肌细胞死亡和caspase-3/-7活性。结论:circNCX1通过靶向miR-103-3p促进DOX诱导的心肌细胞凋亡。     

miR-25对缺氧/复氧诱导的H9c2细胞凋亡的作用

目的:探讨微小RNA-25(miR-25)在缺氧/复氧诱导的H9c2细胞凋亡过程中的作用及机制。方法:构建miR-25高表达H9c2细胞系,行缺氧/复氧损伤处理,real-time PCR检测miR-25及高迁移率族蛋白B1(HMGB1)mRNA的表达,Western blot检测HMGB1及细胞凋亡相关蛋白Bcl-2和cleaved caspase-3的蛋白表达水平,流式细胞术检测细胞凋亡及细胞周期的变化,明确miR-25的高表达对缺氧/复氧所诱导的H9c2细胞凋亡及HMGB1表达的影响。然后通过双萤光素酶报告基因验证miR-25与HMGB1的靶向关系,并构建转染HMGB1 shRNA的H9c2稳定细胞系,行缺氧/复氧损伤处理,验证HMGB1是否参与缺氧/复氧诱导的H9c2细胞凋亡的调控。结果:与对照组相比,高表达miR-25组的H9c2细胞在缺氧/复氧诱导后HMGB1表达下调,Bcl-2表达上调,cleaved caspase-3蛋白水平下调,流式细胞术提示处于S期的细胞增多,G1期减少(P0.01)。双萤光素报告基因显示,转染miR-25 mimic+野生型HMGB1-3’UTR报告基因载体组萤光素酶活性明显下降;转染miR-25 inhibitor+野生型HMGB1-3’UTR和转染miR-25 mimic+突变型HMGB1-3’UTR报告基因载体组萤光素酶活性没有变化。转染HMGB1-shRNA的H9c2细胞中抗凋亡蛋白Bcl-2表达上调,凋亡蛋白cleaved caspase-3蛋白水平下调,流式细胞术分析提示细胞凋亡减少,处于S期的细胞增多,G1期减少(P0.05)。结论:miR-25减少缺氧/复氧诱导的H9c2细胞凋亡,期作用机制可能与靶向调控HMGB1表达有关。     

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。     

MicroRNA-29a对大鼠心肌细胞Bcl-2和Mcl-1表达的调控作用及其机制

 目的：探讨microRNA-29a（miR-29a）对大鼠心肌细胞(CM细胞)B细胞白血病/淋巴瘤-2（Bcl-2） 和髓样细胞白血病-1（Mcl-1）表达的调控机制。方法：体外培养新生Sprague-Dawley大鼠CM细胞和人胚肾细胞株293T。合成大鼠miR-29a的拟似物（mimic）和抑制剂（inhibitor）。用脂质体Lipofectamine RNAiMAX转染miR-29a mimic进入CM细胞，转染 48 h后分别用实时荧光定量PCR和Western blotting检测Bcl-2和Mcl-1 mRNA和蛋白的表达变化。构建Bcl-2 和Mcl-1 的萤光素酶报告基因载体（DNA质粒），转染293T 细胞(DNA质粒和miRNA共转染)和CM细胞（miRNA和 DNA 质粒先后转染），双萤光素酶报告基因系统检测萤光素酶的表达变化。结果：CM细胞转染miR-29a mimic 48 h后，Bcl-2 和Mcl-1 mRNA和蛋白的水平均下调（P<0.05）。双萤光素酶报告基因系统显示，在293T细胞中，miR-29a可特异抑制带有 bcl-2和mcl-1 3’UTR上野生型识别元件的报告基因表达（P<0.05），在CM细胞中，抑制内源性的miR-29a水平能促进bcl-2和mcl-1 3’UTR上野生型识别元件的报告基因表达。结论：抗凋亡基因bcl-2和mcl-1是miR-29a的靶基因。miR-29a可能通过作用于Bcl-2和Mcl-1实现对心肌细胞凋亡的调控作用，具体效应仍待进一步阐明。     

程序化细胞死亡因子5对缺氧/复氧诱导的心肌细胞凋亡和自噬的影响及机制

目的:探讨程序化细胞死亡因子5(PDCD5)对缺氧/复氧(H/R)诱导的心肌细胞凋亡和自噬的影响及其作用机制。方法:以H9c2心肌细胞系为研究对象,建立H/R损伤模型,采用RNA干扰方法抑制PDCD5的表达,MTT法检测心肌细胞的存活率,TUNEL显色法检测细胞凋亡率,RT-qPCR和Western blot法分别检测mRNA和蛋白的表达水平。结果:H/R损伤的H9c2心肌细胞中,PDCD5表达水平升高,同时细胞的存活率降低,细胞凋亡率和自噬水平增加,而PDCD5沉默能够增加细胞存活率,同时减少细胞凋亡率,促进Bax表达且抑制抑Bcl-2、LC3-Ⅱ/LC3-Ⅰ及自噬相关蛋白beclin-1的表达。此外,沉默PDCD5可通过降低p-P65的蛋白水平抑制NF-κB通路。结论:沉默PDCD5通过阻断NF-κB信号通路而抑制H/R损伤诱导的心肌细胞凋亡和自噬,从而保护心肌细胞。     

miR-30a抑制Ang2诱导的大鼠心肌细胞系H9c2自噬

目的探索miR-30a对血管紧张素2(Ang2)诱导的大鼠心肌细胞自噬的影响。方法 1)将H9c2细胞分为对照组(control)、Ang2处理组(Ang2 2×10~(-6) mol/L)、去甲肾上腺素阳性对照组(NE 5×10~(-6) mol/L)。处理细胞48 h, RT-qPCR检测miR-30a表达;Western blot检测LC3、Beclin-1自噬蛋白表达。2)将miR-30a mimics、miR-30a inhibitor、miR-30a NC通过Lipofectamine 2000转染至H9c2细胞中培养24 h,荧光显微镜检测转染率;转染成功后在Ang2刺激基础上设立Ang2+miR-30a mimics组、Ang2+miR-30a inhibitor组、Ang2+miR-NC组。检测miR-30a干预对Ang2诱导H9c2心肌细胞自噬的影响。结果 1)与对照组相比,Ang2处理组、NE阳性对照组miR-30a mRNA表达显著下调(P0.05);而LC3、Beclin-1蛋白表达显著升高(P0.001);2)与Ang2处理组相比,Ang2+miR-30a mimics组LC3、Beclin1蛋白表达显著降低(P0.001)。结论 Ang2能下调miR-30a表达,诱导H9c2心肌细胞自噬;miR-30a mimics能够抑制Ang2诱导的H9c2心肌细胞自噬。     

miR-323通过FGF9调控缺氧诱导的心肌H9C2细胞凋亡

目的:探讨微小RNA-323(miR-323)对缺氧诱导大鼠心肌H9C2细胞凋亡的影响及其机制。方法:建立缺氧损伤的H9C2细胞模型,在H9C2细胞转染anti-miR-323、pcDNA-FGF9和si-FGF9,并缺氧处理48 h。采用qPCR检测miR-323的表达,Western blot检测成纤维细胞生长因子9(FGF9)、cleaved caspase-3、c-Jun氨基末端激酶(JNK)和p-JNK的蛋白水平,MTT比色法检测细胞活力,流式细胞术检测细胞凋亡。生物学信息预测miR-323的靶基因并用双萤光素酶报告基因进一步验证。结果:缺氧明显降低H9C2细胞12 h、24 h和48 h的细胞活力(P<0.05),显著提高细胞凋亡率和cleaved caspase-3的蛋白水平(P<0.05),效应均呈时间依赖性。缺氧处理的H9C2细胞中miR-323和p-JNK水平上调,FGF9蛋白表达下调(P<0.05)。下调miR-323表达或过表达FGF9显著提高缺氧处理的H9C2细胞活力,降低细胞凋亡率和cleaved caspase-3蛋白的水平(P<0.05)。FGF9是miR-323的靶基因。下调FGF9表达逆转下调miR-323表达对缺氧诱导H9C2细胞损伤的抑制作用。miR-323调控FGF9影响p-JNK水平。结论:miR-323通过靶向FGF9调节JNK信号通路,从而影响缺氧处理心肌H9C2细胞的活力和凋亡。     

miR-9和miR-124共表达载体的构建与靶分子鉴定

目的构建miR-9和miR-124单独表达和串联共表达的真核表达载体,并鉴定其共同靶分子。方法将pri-miR-9和pri-miR-124的编码序列分别插入或串联后插入真核表达载体p CAG,转染He La细胞后,实时定量PCR鉴定成熟miRNA的表达水平。构建miR-9和miR-124分子完全互补的靶基因萤光素酶报告载体,双萤光素酶报告系统检测表达的成熟miRNA的生物学功能。利用生物信息学软件预测miR-9和miR-124的共同靶分子,将靶分子mRNA的3'非翻译区(UTR)克隆入p GL3luciferase报告基因载体中,观察转染细胞后miRNA对报告基因表达的影响。结果经测序及酶切鉴定证实3种miRNA表达载体构建完全正确,实时定量PCR检测表明这3种表达载体均能正确高表达成熟的miRNA。双萤光素酶报告系统检测证实3种载体表达的miRNA分子具有生物学活性。生物学软件预测发现小分子GTP结合蛋白Ras相关蛋白2a(Rap2a)是miR-9和miR-124的靶基因,成功构建了含有Rap2a 3'UTR的萤光素酶报告基因载体。双萤光素酶报告系统提示miR-9和miR-124均能抑制Rap2a的表达。结论成功构建了miR-9和miR-124的单独表达和共表达载体,并能高表达具有生物学活性的成熟的miR-9和miR-124分子。Rap2a可能是miR-9和miR-124的一个共同靶分子。     

Overexpression of angiopoietin-1 reduces doxorubicin-induced apoptosis in cardiomyocytes

Doxorubicin(Dox) is a major anticancer chemotherapeutic agent.However,it causes cardiomyopathy due to the side effect of cardiomyocyte apoptosis.We have previously reported that angiopoietin-1 significantly reduced myocardial infarction after ischemic injury and protected cardiomyocytes from oxidative stress-induced apoptosis.It is hypothesized that angiopoietin-1 may protect cardiomyocytes from Dox-induced apoptosis.Cardiomyocytes H9C2 were transfected with adenovirus expressing angiopoietin-1(Ad5-Ang-1) 24 h before the cells were challenged with Dox at a concentration of 2 μmol/L.Ad5-GFP served as the vector control.Cardiomyocyte apoptosis was evaluated using Annexin V-FITC staining and caspase-3 and caspase-8 activity was determined by Western blotting.The results showed that Dox treatment significantly induced cardiomyocyte apoptosis as evidenced by the greater number of Annexin V-FITC stained cells and increases in caspase-3 and caspase-8 activity.In contrast,overexpression of angiopoietin-1 significantly prevented Dox-induced cardiomyocyte apoptosis.To elucidate the mechanisms by which angiopoietin-1 protected cells from Dox-induced apoptosis,we analyzed both extrinsic and intrinsic apoptotic signaling pathways.We observed that angiopoietin-1 prevented Dox-induced activation of both extrinsic and intrinsic apoptotic signaling pathways.Specifically,angiopoietin-1 prevented DOX-induced increases in FasL and Bax levels and cleaved caspase-3 and caspase-8 levels in H9C2 cells.In addition,overexpression of angiopoietin-1 also activated the pro-survival phosphoinositide-3 kinase(PI3K)/Akt signaling pathway and decreased Dox-induced nuclear factor-kappaB(NF-κB) activation.Our data suggest that promoting the expression of angiopoietin-1 could be a potential approach for reducing Dox-induced cardiomyocyte cytoxicity.     

MEF2C介导microRNA-214发挥抑制心肌细胞肥大的作用

目的:研究微小RNA-214(mi R-214)对心肌细胞肥大的调控作用及其可能的作用靶基因。方法:建立血管紧张素Ⅱ(angiotensin-Ⅱ,Ang-Ⅱ)诱导的C57BL/6乳小鼠心室肌细胞肥大模型;双萤光素酶报告基因实验检测mi R-214与潜在靶基因MEF2C 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MEF2C及肥厚标志物的m RNA和蛋白表达水平。结果:心肌肥厚标志物ANP、ACTA1和β-MHC,以及mi R-214的表达在Ang-II诱导肥大的小鼠心肌细胞中显著增强;双萤光素酶报告基因实验提示mi R-214与MEF2C 3’UTR相互作用,证实mi R-214可在转录水平抑制MEF2C的表达,MEF2C蛋白水平在肥大的心肌细胞中显著上调;过表达mi R-214及沉默MEF2C均能一致性地抑制Ang-Ⅱ诱导的心肌细胞中肥大标志物的表达。结论:MEF2C是mi R-214的靶基因,并介导了mi R-214发挥抑制心肌细胞肥大的作用。     

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。     

miR-217调控lncRNAMALAT1影响食管鳞癌细胞的生物学行为

目的　探讨miR-217通过调控lncRNA MALAT1抑制食管鳞状细胞癌细胞的增殖,迁移和侵袭行为及其机制。 方法　qPCR检测miR-217在食管鳞状细胞癌组织和不同细胞株中的表达情况;双荧光素酶报告基因检测miR-217与MALAT1之间的相互作用;MTT增殖实验检测抑制miR-217后食管鳞状细胞癌细胞的增殖能力的变化情况;划痕愈合试验和Transwell侵袭实验检测抑制miR-217后食管鳞状细胞癌细胞的迁移和侵袭行为的变化情况;Western blotting实验检测miR-217对MALAT1下游相关蛋白表达情况的影响。 结果　与正常食管组织相比,食管鳞状细胞癌组织中miR-217的表达水平相对上调,与其他细胞株相比,Ec109细胞中miR-217表达最高;双荧光素酶实验证实miR-217能与MALAT1的3’ UTR特异性结合,可以调控MALAT1的表达与活性;抑制miR-217的表达后可以抑制食管鳞状细胞癌细胞的增殖、迁移和侵袭能力;抑制miR-217后MALAT1下游MIA2,ROBO1表达明显下调。 结论　miR-217可以调控MALAT1的表达影响食管鳞状细胞癌细胞的生物学行为。     

反义miR-196a对人胰腺癌PANC-1细胞侵袭和迁移的抑制作用

目的:探讨微小RNA-196a(miR-196a)在胰腺癌细胞系中表达状况及反义miR-196a对人胰腺癌PANC-1细胞生物学行为的影响。方法:miR-196a采用实时荧光定量PCR检测。人工化学合成反义miR-196a并转染PANC-1细胞。CCK-8法检测细胞增殖。流式细胞术检测细胞凋亡情况。通过划痕损伤实验和Transwell小室细胞侵袭、迁移实验检测PANC-1细胞侵袭和迁移能力。构建野生型及突变型核因子κB抑制蛋白α(NFKBIA)3'UTR的萤光素酶报告载体,检测海肾萤光素酶的相对活性以验证miR-196a对NFKBIAmRNA的作用靶点。结果:人胰腺癌细胞系中miR-196a呈高表达;转染反义miR-196a后,PANC-1细胞miR-196a表达下降,其细胞增殖和凋亡无显著改变(P>0.05);而转染反义miR-196a组中通过Transwell小室的细胞数明显低于各对照组(P<0.01)。与各对照组相比,共转染野生型NFKBIA的3'UTR和反义miR-196a可使海肾萤光素酶相对活性显著提高。结论:miR-196a可能是癌微RNA(oncomiR)之一,有望成为人胰腺癌基因治疗的候选靶点。     

microRNA-34a aggravates coxsackievirus B3-induced apoptosis of cardiomyocytes through the SIRT1-p53 pathway

Viral myocarditis is inflammation of the myocardium mainly caused by a viral infection, and coxsackievirus B3 (CVB3) infection is one of the most common. It is well known that cardiomyocyte apoptosis is involved in the pathogenesis of viral myocarditis. microRNAs (miRNAs, miRs) are endogenous noncoding oligoribonucleotides involved in various pathological conditions, and miR-34a is one of the miRNAs causing apoptosis. Whether miR-34a participates in cardiomyocyte apoptosis during CVB3 infection and the underlying mechanisms is still unclear. In this in vitro study, we found that miR-34a expression increased in cardiomyocytes after CVB3 infection. Furthermore, we found that CVB3 infection augmented histone deacetylase 1 (HDAC1) and Bax expression while inhibiting sirtuin 1 (SIRT1) and Bcl-2 expression, along with the acetylated p53 (Ac-p53) upregulation in cardiomyocytes. The above-mentioned phenomenon was reversed by a miR-34a inhibitor after CVB3 infection. In addition, the Ac-p53 amount increased in CVB3-infected cardiomyocytes, and SRT1720 and trichostatin A (TSA) pretreatment decreased Ac-p53 levels. After pifithrin-α pretreatment of CVB3-infected cardiomyocytes, the protein expression level of HDAC1 decreased while that of SIRT1 increased. Moreover, miR-34a expression and CVB3-induced apoptosis of cardiomyocytes were attenuated by pretreatment with SRT1720, TSA, or pifithrin-α, accompanied with Bax downregulation and Bcl-2 upregulation. In summary, these data indicate that miR-34a induces cardiomyocyte apoptosis by downregulating SIRT1, and the activation of the SIRT1-p53 pathway contributes to CVB3-induced apoptosis of cardiomyocytes. Thus, miR-34a might serve as a potential therapeutic target because it promotes cardiomyocyte apoptosis through the SIRT1-p53 signaling pathway.     

miR-23a和ESRP1在直肠癌中的作用

目的:研究miR-23a和上皮剪接调节蛋白1(epithelial splicing regulatory protein 1,ESRP1)在直肠癌组织及细胞系中的表达,以及对体外直肠癌细胞活力和凋亡的作用。方法:采用RT-q PCR分析miR-23a在36例直肠癌组织和癌旁组织中的表达,免疫组化检测ESRP1在直肠癌组织中的表达,分析miR-23a和ESRPl在直肠癌组织中的相关性;利用RT-q PCR检测miR-23a在直肠癌Caco-2和SW480细胞及人正常结肠上皮细胞株NCM460中的表达;合成miR-23a inhibitor和inhibitor阴性对照(inhibitor NC),并将其分别转染至SW480细胞后,通过CCK-8法检测miR-23a inhibitor转染SW480细胞后对细胞活力的影响,流式细胞术检测转染后细胞凋亡率,Transwell小室实验检测细胞侵袭;通过Western blot技术检测SW480细胞中ESRPl蛋白的表达;构建野生型pGL3-ESRP1-3’UTR(wt-pGL3-ESRP1-3’UTR)或突变型pGL3-ESRP1-3’UTR(mut-pGL3-ESRP1-3’UTR)质粒,并分别与miR-23a inhibitor或inhibitor NC共转染至HEK293和SW480细胞中,利用双萤光素酶报告基因检测试剂盒说明检测双萤光素酶活性;将ESRP1 mimic或mimic NC瞬时转染SW480细胞后,CCK-8法和流式细胞术分别检测细胞活力和凋亡;Western blot法检测瞬转ESRP1 mimic后对ESRP1、caspase-3、Smac和XIAP蛋白表达的影响。结果:miR-23a和ESRP1在直肠癌组织的表达较癌旁正常组织分别上调和下调,两者呈明显负相关(P0.01);miR-23a的表达与直肠癌的淋巴结转移和肿瘤浸润深度相关;与NCM460细胞相比较,miR-23a在SW480细胞中的表达量显著上调(P0.01);转染miR-23a inhibitor后,SW480细胞活力较inhibitor NC组显著下降(P0.01);转染miR-23a inhibitor后SW480细胞早期凋亡率明显升高,同时细胞体外侵袭能力受到抑制;萤光素酶报告基因结果表明ESRP1是miR-23a的直接靶基因;转染miR-23a inhibitor至SW480细胞后ESRP1蛋白表达水平明显升高;ESRP1 mimic转染SW480细胞后可抑制细胞活力并诱导细胞凋亡,同时上调caspase-3和Smac的表达,下调XIAP的表达。结论:miR-23a可通过负向调控下游靶基因ESRP1从而影响直肠癌细胞生长和凋亡。     

CO and bilirubin inhibit doxorubicin-induced cardiac cell death

The clinical utility of anthracycline anticancer agents, especially doxorubicin (DOX), is limited by progressive toxic cardiomyopathy linked to cardiomyocyte apoptosis. This study examined the protective effects of CO and bilirubin on DOX-induced cardiomyocyte toxicity. In vitro, DOX significantly decreased the viability of H9c2 cells and increased apoptotic features, such as changes in nuclear morphology and caspase protease activation. CO and bilirubin significantly inhibited DOX-induced cell death and caspase-3 activation, which may be explained by increased Bcl-2 expression and inhibition of Bax expression. CO and bilirubin up-regulated the heme oxygenase-1 (HO-1), which was required for the protective effect of CO, and a single bilirubin treatment increased DOX-induced apoptosis in H9c2 cells. The inhibition of HO-1 with ZnPP resulted in a striking increase in apoptosis in the CO, bilirubin, and DOX-treated cells. Furthermore, HO-1 overexpression increased resistance against DOX-induced cytotoxicity in H9c2 cells. In conclusion, CO and bilirubin can inhibit DOX-induced apoptosis in H9c2 cardiomyocytes. These findings imply that the therapeutic index of anthracycline cancer chemotherapeutics can be improved by protecting against cardiomyocyte death.     

CO and bilirubin inhibit doxorubicin-induced cardiac cell death

The clinical utility of anthracycline anticancer agents, especially doxorubicin (DOX), is limited by progressive toxic cardiomyopathy linked to cardiomyocyte apoptosis. This study examined the protective effects of CO and bilirubin on DOX-induced cardiomyocyte toxicity. In vitro, DOX significantly decreased the viability of H9c2 cells and increased apoptotic features, such as changes in nuclear morphology and caspase protease activation. CO and bilirubin significantly inhibited DOX-induced cell death and caspase-3 activation, which may be explained by increased Bcl-2 expression and inhibition of Bax expression. CO and bilirubin up-regulated the heme oxygenase-1 (HO-1), which was required for the protective effect of CO, and a single bilirubin treatment increased DOX-induced apoptosis in H9c2 cells. The inhibition of HO-1 with ZnPP resulted in a striking increase in apoptosis in the CO, bilirubin, and DOX-treated cells. Furthermore, HO-1 overexpression increased resistance against DOX-induced cytotoxicity in H9c2 cells. In conclusion, CO and bilirubin can inhibit DOX-induced apoptosis in H9c2 cardiomyocytes. These findings imply that the therapeutic index of anthracycline cancer chemotherapeutics can be improved by protecting against cardiomyocyte death.