MiR-186-5p对3T3-L1前脂肪细胞增殖分化的影响研究

目的:探究miR-186-5p对小鼠3T3-L1前脂肪细胞增殖、分化的影响及其潜在的分子机制。方法:qRT-PCR检测miR-186-5p在不同周龄小鼠白色脂肪组织及3T3-L1前脂肪细胞增殖分化过程中的表达变化;通过脂质体将miR-186-5p mimics、inhibitors转染入增殖液或分化液培养的3T3-L1细胞后,利用CCK-8、EdU和qRT-PCR检测3T3-L1前脂肪细胞增殖变化,油红O染色观察其脂滴形态;通过生物信息软件TargetScan和双荧光报告系统分别对miR-186-5p靶基因进行预测和确认。结果:(1) miR-186-5p在1～6周龄小鼠的白色脂肪组织及3T3-L1前脂肪细胞自然分化过程中表达量均逐渐上调。(2)与阴性对照相比,mimics或inhibitors转染分别显著地促进或抑制了miR-186-5p的表达。(3)过表达miR-186-5p后,3T3-L1前脂肪细胞的增殖速率减慢,脂滴增大增多;而抑制miR-186-5p后,3T3-L1前脂肪细胞增殖速率增快,脂滴数量减少,且粒径变小。其中过表达miR-186-5p显著地降低了野生型Wnt5a和Mapk1 3'-UTR活性,而突变相应的绑定位点可解除该抑制作用。结论:miR-186-5p可抑制3T3-L1前脂肪细胞增殖,且通过直接靶向Wnt5a和Mapk1以促进其分化为成熟脂肪细胞。     

MiR-186-5p对3T3-L1前脂肪细胞增殖分化的影响研究 *

目的 探究miR-186-5p对小鼠3T3-L1前脂肪细胞增殖,分化的影响及其潜在的分子机制.方法: qRT-PCR检测miR-186-5p在不同周龄小鼠白色脂肪组织及3T3-L1前脂肪细胞增殖分化过程中的表达变化;通过脂质体将miR-186-5p mimics,inhibitors转染入增殖液或分化液培养的3T3-L1细胞后,利用CCK-8,EdU和qRT-PCR检测3T3-L1前脂肪细胞增殖变化,油红O染色观察其脂滴形态;通过生物信息软件TargetScan和双荧光报告系统分别对miR-186-5p靶基因进行预测和确认.结果: (1)miR-186-5p在1~6周龄小鼠的白色脂肪组织及3T3-L1前脂肪细胞自然分化过程中表达量均逐渐上调.(2)与阴性对照相比,mimics或inhibitors转染分别显著地促进或抑制了miR-186-5p的表达.(3)过表达miR-186-5p后,3T3-L1前脂肪细胞的增殖速率减慢,脂滴增大增多;而抑制miR-186-5p后,3T3-L1前脂肪细胞增殖速率增快,脂滴数量减少,且粒径变小.其中过表达miR-186-5p显著地降低了野生型Wnt5a和Mapk1 3'-UTR活性,而突变相应的绑定位点可解除该抑制作用.结论: miR-186-5p可抑制3T3-L1前脂肪细胞增殖,且通过直接靶向Wnt5a和Mapk1以促进其分化为成熟脂肪细胞.     

MiR-125a-5p抑制3T3-L1前体脂肪细胞分化

MicroRNAs(miRNAs) 是一类在脂肪组织发育中发挥重要作用的小非编码RNA. 为探明miR-125a-5p在3T3-L1前体脂肪细胞中的作用,采用实时qPCR检测了miR-125a-5p在小鼠各组织及3T3-L1前体脂肪细胞分化过程中的表达|使用经化学修饰的miR-125a-5p模拟物agomir及抑制剂antagomir转染3T3-L1前体脂肪细胞,采用实时qPCR 和 Western印迹检测成脂标志基因Pparγ和aP2的表达,油红O染色观察脂肪细胞脂质积累. 结果显示,miR-125-5p在小鼠脂肪组织中高丰度表达,在3T3-L1前体脂肪细胞分化过程中表达下降.过表达miR-125a-5p,与对照组相比,成脂标志基因Pparγ和aP2在mRNA和蛋白质水平均明显下降|油红O染色及定量结果显示脂质积累减少. 抑制剂处理结果显示,Pparγ和aP2在mRNA和蛋白质水平均有不同程度上升,但油红O染色及定量结果差异不显著. 以上结果表明,miR-125a-5p在脂肪细胞分化中发挥负调控作用.     

miR-130a-3p调控SOX4对骨关节炎软骨细胞增殖、分化和炎症因子释放的影响

目的:探讨miR-130a-3p对骨关节炎(osteoarthritis, OA)软骨细胞增殖、分化和炎症因子释放的影响及作用机制。方法:收集我院住院的40例半月板损伤患者和40例OA患者,采用RT-PCR检测半月板损伤患者和OA患者膝关节软骨组织中miR-130a-3p的表达。在OA软骨细胞中分别转染miR-NC、miR-130a-3p mimics、miR-130a-3p inhibitors、si RNA-SOX4(si-SOX4)或过表达SOX4的慢病毒载体(LV-SOX4),采用CCK8法检测细胞增殖情况;RT-PCR和western blot检测细胞分化相关分子BMP2和BMP4;RT-PCR检测炎症因子IFN-γ和TNF-α的表达。结果:半月板损伤患者软骨组织和软骨细胞中miR-130a-3p的表达明显高于OA患者(P均0.05),而SOX4的表达水平明显低于OA患者(P0.05)。OA患者膝关节软骨组织中miR-130a-3p和SOX4的表达呈显著负相关(P0.05)。miR-130a-3p mimics能够明显促进OA软骨细胞增殖(P0.05)、增加分化相关分子BMP2和BMP4的表达(P均0.05)以及抑制炎症因子IFN-γ和TNF-α的表达(P均0.05)。miR-130a-3p inhibitors能够明显抑制OA软骨细胞增殖(P0.05)、分化相关分子BMP2和BMP4的表达(P均0.05)以及促进炎症因子IFN-γ和TNF-α的表达(P均0.05)。OA软骨细胞在转染miR-130a-3p mimics后,SOX4 mRNA和蛋白的表达水平明显降低(P均0.05),在转染miR-130a-3p inhibitors后,SOX4 mRNA和蛋白的表达水平明显升高(P均0.05)。双荧光素酶结果显示miR-130a-3p能够靶向结合SOX4。在OA软骨细胞中,采用si RNA低表达SOX4后,明显促进细胞增殖和分化以及抑制炎症因子的释放。共转染miR-130a-3p mimics和LV-SOX4能够逆转过表达miR-130a-3p对OA软骨细胞增殖、分化和炎症因子释放的影响(P均0.05),而共转染miR-130a-3p inhibitors和LV-SOX4能够进一步加强低表达miR-130a-3p对OA软骨细胞增殖、分化和炎症因子的影响(P均0.05)。结论:miR-130a-3p在OA中明显低表达,并能够通过靶向抑制SOX4促进OA软骨细胞增殖、分化和炎症因子释放。     

MiR-324-5p可能通过靶向淀粉样前体蛋白抑制棕榈酸诱导的3T3-L1脂肪细胞凋亡

miRNAs是一种非编码的小RNA,通过靶向mRNA的3′UTR调控基因的转录后翻译。为明确miR-324-5p对棕榈酸诱导的3T3-L1脂肪细胞凋亡的作用和机制,体外培养3T3-L1脂肪细胞,利用棕榈酸诱导细胞凋亡的同时过表达或抑制miR-324-5p,通过Annexin-V/FITC染色、RT-qPCR等方法检测miR-324-5p对3T3-L1脂肪细胞凋亡的作用。通过在线软件预测miR-324-5p的靶基因并进行验证。结果显示,过表达miR-324-5p能够显著抑制凋亡相关基因BCL-2相关X蛋白(BCL2-associated X protein, Bax)和胱天蛋白酶3(caspase3)的表达水平(P0.05);而抑制miR-324-5p后能够显著促进这些基因的表达(P0.05);靶基因预测及验证结果表明,miR-324-5p能够显著降低淀粉样前体蛋白(amyloid precursor protein, APP)的表达水平(P0.05)。本研究认为,miR-324-5p可能通过靶定APP抑制棕榈酸诱导的3T3-L1脂肪细胞凋亡。     

Rheb过表达在前体脂肪细胞株3T3-L1分化中的作用

目的:利用前体脂肪细胞株3T3-L1细胞观察mTOR(mammalian target of rapamycin)信号通路中上游调控因子Rheb(Ras homolog enriched in brain)对其分化的影响。方法:利用高表达Rheb的基因重组质粒转染前体脂肪细胞株,3T3-L1。通过蛋白质免疫印迹实验鉴定质粒成功转染细胞后,诱导该细胞脂肪分化。予以分化第8天的3T3-L1细胞油红染色,并检测细胞内甘油三酯的含量。另外,我们用Western blot方法检测脂肪细胞特异性转录因子PPAR-γ(Peroxisome proliferator-activated receptor-γ)和C/EBP-α(CCAAT-enhancer-binding protein-α)的表达情况来研究Rheb在脂肪细胞分化过程中的作用。结果:我们成功构建了高表达Rheb的3T3-L1细胞株,发现高表达Rheb后可以促进脂滴的生成,油红O染色有显著区别,与对照组相比Rheb高表达组的三酰甘油含量明显升高(P0.05);C/EBP-α和PPAR-γ等脂肪细胞特异性的转录因子蛋白表达量与对照组相比也均有升高(P0.05)。结论:Rheb基因作为mTOR通路上游调控因子,可以促进脂肪细胞的分化。     

MiR-130a 在猪皮下脂肪细胞分化中的调节作用

为研究miR-130a对猪皮下脂肪细胞分化的影响及可能机制,本试验分离猪皮下脂肪前体细胞,诱导分化为成熟脂肪细胞,检测脂肪细胞分化过程中脂滴变化及miR-130a及其可能靶基因TNF α和PPARγ的表达模式.同时合成miR-130a mimics及inhibitor 对细胞进行转染,并以乱序序列作为阴性对照（NC）.细胞转染24 h后进行诱导分化,连续诱导8 d,检测各处理细胞的聚脂情况及甘油三酯含量变化,荧光定量PCR检测脂肪细胞分化相关基因的表达变化.结果显示,猪皮下脂肪前体细胞分化过程中脂滴逐渐变大增多,miR-130a、TNF α和PPARγ的表达模式具有一定的相似性.转染结果显示,相对于对照组,miR 130a mimics转染组细胞脂滴减少变小,甘油三酯含量降低（P<0.05）,脂肪细胞分化相关基因LPL、PPARγ、adiponectin、FASN和葡萄糖转运相关基因GLUT1,GLUT4以及JNK通路上的PDE3B的表达均比对照组显著下调（P<0.01）;而miR-130a inhibitor转染组细胞则脂滴增多,甘油三酯含量提高（P<0.05）,但大部分分化相关基因的表达与对照组无显著差异,提示miR-130a可能不只通过单一的靶基因影响脂肪细胞分化.其结果为后续深入研究miR-130a调节猪脂肪细胞分化的通路及机制奠定基础.     

miR-382-5p通过靶基因PTEN阻滞NB4细胞分化

该文主要研究在急性早幼粒细胞白血病NB4细胞中, miR-382-5p通过调控靶基因PTEN(phosphatase and tensin homologue)抑制了全反式维甲酸(all-trans retinoic acid, ATRA)诱导的急性早幼粒细胞分化。我们运用ATRA(1μmol/L)诱导细胞分化; Western blot检测PTEN及髓系分化标志物CD11b的蛋白质水平;实时荧光定量PCR检测miR-382-5p的表达水平;过表达PTEN的慢病毒载体分别感染NB4细胞和HL-60、THP-1细胞;脂质体转染miR-382-5p的模拟剂(mimics)和特异性抑制剂(inhibitors)NB4细胞。结果显示, PTEN促进ATRA诱导的NB4细胞分化,而在HL-60和THP-1细胞中并无明显促分化效应。NB4细胞中,脂质体转染miR-382-5p mimics在mRNA和蛋白水平均抑制了PTEN的表达,并且抑制了ATRA诱导的分化;转染miR-382-5p inhibitors则恢复了PTEN表达,同时促进了ATRA诱导的急性早幼粒细胞NB4细胞的分化。该文结果提示, miR-382-5p靶向抑制了PTEN的表达从而抑制ATRA诱导的NB4细胞分化。     

CRISPR/Cas9敲除PLIN1基因增强3T3-L1脂肪细胞的脂解作用

应用CRISPR/Cas9技术敲除3T3-L1前脂肪细胞plin1,观察PLIN1缺失对脂肪细胞中脂肪水解的影响并探究可能机制。常规培养3T3-L1前脂肪细胞,电穿孔法转染plin1敲除载体,嘌呤霉素培养基挑选plin1敲除细胞,观察转染及筛选后的细胞存活率。"鸡尾酒"法诱导3T3-L1前脂肪细胞分化,酶法测定甘油和TG含量,油红O染色观察脂滴形态及数目的变化。Western blotting检测PLIN1、PPARγ、Fsp27和脂肪酶的蛋白表达;RT-PCR检测PLIN1和脂肪酶的mRNA表达。对照组细胞诱导分化后,微小脂滴数目较少,单房脂滴数目较多并围绕细胞核呈环型排列。相较于对照组,敲除组细胞诱导分化后微小脂滴数目增加,单房脂滴体积缩小,数目减少;细胞中PLIN1mRNA及蛋白表达被显著抑制(P0.05);甘油水平显著上升(0.0984±0.0076),TG含量显著下降(0.031 0±0.005 3);HSL和ATGL两种脂肪酶的mRNA及蛋白表达均升高(P0.05);PPARγ和Fsp27的表达未有明显变化。上述结果表明plin1敲除后通过暴露脂滴中脂质以及上调脂肪酶等效应增强了3T3-L1脂肪细胞的脂解作用。     

长非编码RNA ILF3-AS1通过调控miR-130a-3p/PTEN轴抑制宫颈癌细胞的增殖

ILF3反义RNA 1（ILF3 antisense RNA 1,ILF3-AS1）是一条定位于染色体19p13.2的lncRNA,它是白介素增强子结合因子3 (interleukin enhancer binding factor 3,ILF3)的反义RNA。ILF3-AS1在多种肿瘤发生发展中发挥关键作用,但其在宫颈癌中的作用尚无研究探讨。本文利用TCGA及GTEx数据库进行生物信息学分析提示,ILF3-AS1在宫颈癌组织中低表达（P<0.001）并与良好预后相关（P=0.045）。qRT-PCR结果显示,ILF3-AS1在宫颈癌组织及SiHa、HeLa、CaSki宫颈癌细胞系中表达较对照组均呈下降趋势。过表达ILF3-AS1可明显抑制宫颈癌细胞增殖活力及促进宫颈癌细胞凋亡。Star Base v3.0数据库分析提示,ILF3-AS1可靶向吸附miR-130a-3p;而miR-130a-3p可靶向结合PTEN。qRT-PCR检测显示,miR-130a-3p在宫颈癌中的表达量明显高于正常宫颈组织（P<0.01）。荧光素酶报告基因结果显示,ILF3-AS1可以与miR-130a-3p 特异性结合（P<0.01）。HeLa细胞过表达ILF3-AS1后,miR-130a-3p表达量明显下调（P<0.01）;在过表达ILF3-AS1细胞中,同时转染miR-130a-3p mimics,能部分逆转LF3-AS1对于细胞增殖的抑制作用（P<0.001）。HeLa细胞在过表达ILF3-AS1后,磷酸酶及张力蛋白同源物基因(phosphatase and tensin homolog deleted on chromosome ten,PTEN) mRNA（P<0.001）及蛋白质（P<0.001）表达量显著升高;当同时转染miR-130a-3p mimics,PTEN的 mRNA（P<0.001)及蛋白质（P<0.001）的表达升高被明显抑制。综上,ILF3-AS1可以作为miR-130a-3p的吸附海绵靶向调控PTEN表达,从而抑制宫颈癌细胞的增殖。     

Synthesis and biological activity of 3 beta-fluorovitamin D3: comparison of the biological activity of 3 beta-fluorovitamin D3 and 3-deoxyvitamin D3

The alteration in the biologic activity of the vitamin D3 molecule resulting from the replacement of a hydrogen atom with a fluorine atom is a subject of fundamental interest. To investigate this problem we synthesized 3 beta-fluorovitamin D3 6 and its hydrogen analog, 3-deoxyvitamin D3 7, and tested the biologic activity of each by in vitro and in vivo methods. Contrary to previous reports which showed that 3 beta-fluorovitamin D3 was as active as vitamin D3 in vivo, we found that the fluoro-analog was less active than vitamin D3. With regard to stimulation of intestinal calcium transport and bone calcium mobilization in the D-deficient hypocalcemic rat, 3 beta-fluorovitamin D3 showed significantly greater biologic activity than its hydrogen analog, 3-deoxyvitamin D3. In the organ-cultured, embryonic chick duodenum, 3 beta-fluorovitamin D3 was approx 1/1000th as active as the native hormone, 1,25-dihydroxyvitamin D3, while 3-deoxyvitamin D3 was inactive even at microM concentrations, in the induction of the vitamin D-dependent, calcium-binding protein. With regard to in vitro activity in displacing radiolabeled 25-hydroxyvitamin D3 from vitamin D binding protein and radiolabelled 1,25-dihydroxyvitamin D3 from a chick intestinal cytosol receptor, 3 beta-fluorovitamin D3 and 3 beta-deoxyvitamin D3 both showed very poor binding efficiencies when compared with vitamin D3. Our results show that the substitution of a fluorine atom for a hydrogen atom at the C-3 position of the vitamin D3 molecule results in a fluorovitamin 6 with significantly more biological activity than its hydrogen analog, 3-deoxyvitamin D3 7.     

Ether-linked lipids of Balb/c3T3, SV3T3 and concanavalin A-selected SV3T3 revertant cells

Ether-linked lipids were analyzed in Balb/c3T3, SV3T3 and Concanavalin A-selected SV3T3 revertant cells. The three cell lines were found to contain significant quantities of alk-1-enyl- and alkyl-linked phosphatidylethanolamine (PE) and phosphatidylcholine (PC) and small amounts of alkyldiacylglycerols. Compared to 3T3 cells, SV3T3 cells contain a higher amount of alk-1-enyl-linked PC, while in SV3T3 revertant cells the concentrations of the various ether lipids are similar to those of 3T3 cells. The major difference in the composition of ether groups of SV3T3 cells, compared to 3T3 cells, is an increase of 18:0 accompanied by a decrease of 18:1 in the alk-1-enyl-linked PE and PC. Alk-1-enyl-linked PC of SV3T3 revertant cells also shows an increase of 18:0, while the decrease of 18:1 was not statistically significant.     

Export of Galectin-3 from Nuclei of Digitonin-Permeabilized Mouse 3T3 Fibroblasts

Galectin-3 is a galactose-/lactose-binding protein (M(r) approximately 30,000), identified as a required factor in the splicing of pre-mRNA. Immunofluorescence staining revealed that galectin-3 distributes differentially between the nucleus and the cytoplasm, depending on the proliferative state of the cells under analysis. Using digitonin-permeabilized mouse 3T3 fibroblasts, we provide evidence that galectin-3 is rapidly and selectively exported from the nucleus. Although both phosphorylated and nonphosphorylated isoforms of galectin-3 are found in the nuclear fraction, only phosphorylated galectin-3 is identified in the exported fraction, implying that phosphorylation is important for the nuclear export of the protein. The rate of galectin-3 export is temperature dependent and is decreased by the addition of wheat germ agglutinin. More strikingly, galectin-3 export can be inhibited by the addition of leptomycin B, a drug that disrupts the interaction between the leucine-rich nuclear export signal and its receptor, CRM1 (chromosome maintenance region 1). Indeed, a putative leucine-rich nuclear export signal can be found in residues 241-249 of the murine galectin-3 sequence. Finally, gel filtration of the exported material showed that galectin-3 can be found in at least two high molecular weight complexes (approximately 650 and approximately 60 kDa), both of which can be disrupted by lactose.     

Anaerobic degradation of poly-3-hydroxybutyrate and poly-3-hydroxybutyrate-co-3-hydroxyvalerate

The anaerobic degradation of the polyesterspoly-3-hydroxybutyrate (PHB) andpoly-3-hydroxybutyrate-co-3-hydroxyvalerate (PHBV) wasinvestigated with special regard to intermediateproducts, kinetics, and yields. During the degradationof PHBV acetate, propionate, n-butyrate, andn-valerate were detected. Additionally,3-hydroxybutyrate and 3-hydroxyvalerate and fourdimeric esters of these two molecules were identifiedby GC-MS measurements. Three different test systemsfor the anaerobic degradation of polyesters werestudied. It was not possible to get reproducibleresults by means of the Anaerobic Sturm-test, a simplesystem based on carbon dioxide measurement. Secondly,a system based on the GC measurement of accumulatedorganic acids was investigated. A degradation of 90%in two days was calculated by a carbon balance. Bestresults were reached with the third test system basedon the measurement of methane with a gas meter. Adegradation of 99% was observed within 30 days.     

Synchronization of mouse 3T3 and SV40 3T3 cells by way of centrifugal elutriation

Populations of G1 phase 3T3 and SV40 3T3 mouse fibroblasts have been isolated from exponentially growing cultures by the technique of centrifugal elutriation. Return of the G1 phase cells to growth conditions results in their synchronous passage through the cell cycle, as determined from monitoring of cell number, [³H]thymidine ([³H]TdR) incorporation and fraction of [³H]TdR labeled nuclei. The durations of G1, S and G2 phases are consistent with values obtained by previous investigators using conventional induction techniques for synchronization. The method for isolation of the G1 phase cells is rapid, the yield is high and the process does not appear to alter the temporal aspects of the cell cycle in either cell type.     

Properties of 3-hydroxypropionaldehyde 3-phosphate.

Several modifications to the synthesis of the diethyl acetal of 3-hydroxypropionaldehyde-3-P (HPAP) are described. HPAP is liberated from its acetal by treatment with Dowex 50-H⁺ at 40 °C for 4 min, and longer time or higher temperature lower yields. Breakdown of the dianion of HPAP (pK 6.7) is self-catalyzed, with the phosphate acting as a general base to remove a proton from carbon 2 and allow elimination of phosphate to give acrolein. Monoanion breakdown is at least 400-fold slower. At 25 °C the dianion breaks down with k = 0.025 min^?1, and the activation energy for the process is 24 kcal/mol. Buffers have little effect on breakdown of HPAP, except for those containing primary or secondary amines. Thus morpholine enhances breakdown by forming a Schiff's base with a positively charged nitrogen, and Tris inhibits breakdown by forming one with an uncharged nitrogen. The aldehyde group of HPAP is 60% hydrated in water.