对羟基苯甲醇通过SIRT1/PGC-1α/TFAM信号通路抗脑缺血再灌注损伤的作用及机制研究

目的:基于SIRT1/PGC-1α/TFAM信号通路探讨对羟基苯甲醇(HBA)抗脑缺血再灌注损伤作用。方法:通过线栓法复制MCAO/R大鼠模型,分为假手术组、模型组(MCAO/R)、HBA组、抑制剂(EX527)组。其中抑制剂组是侧脑注射EX527(10mmol·L^-1,10μL),HBA治疗组给予HBA 20mg·kg^-1进行药物干预。旷场实验、转棒实验、Morris水迷宫实验观察大鼠行为学变化;TTC法检测脑梗死体积;取缺血侧脑组织,电镜观察线粒体显微结构变化,检测组织中活性氧(ROS)、线粒体膜电位(MMP)、呼吸链酶复合体Ⅰ~Ⅳ活性、ATP水平;免疫组化法检测脑源性神经营养因子(BDNF)和神经生长相关蛋白(GAP-43)蛋白阳性表达;Western blot法检测脑组织中SIRT1、PGC-1a、NRF1/2、TFAM蛋白表达。结果:HBA干预后能改善MCAO/R大鼠记忆空间学习及运动能力等行为学变化,明显降低脑梗死体积;改善线粒体结构损伤,降低ROS水平,提高线粒体呼吸链酶复合体Ⅰ~Ⅳ活性、MMP以及ATP水平。促进BDNF和GAP-43及SIRT1/PGC-1a途径相关蛋白表达。SIRT1抑制剂处理后可逆转HBA的治疗作用。结论:HBA可促进缺血再灌注过程中神经元的修复,其可能与激活SIRT1/PGC-1a/TFAM信号通路有关。     

miR-211通过靶向调控TFAM抑制人乳腺癌细胞系增殖

目的探讨miR-211靶向线粒体转录因子A(TFAM)对人乳腺癌细胞增殖的影响。方法用miR-211及TFAM作为研究对象。首先,在乳腺癌细胞中转染miR-211 mimics或miR-211抑制剂以实现miR-211过表达或miR-211沉默,并检测miR-211过表达或沉默时TFAM蛋白质的表达水平;其次,构建了在TFAM的5'端有或无6对碱基突变的荧光酶报告基因质粒(mut-TFAM/wt-TFAM),与miR-211 mimics或miR-211抑制剂共转染后检测荧光酶活性变化;然后,构建pc DNA3.1/TFAM质粒,与miR-211 mimics或miR-211抑制剂共转染后检测TFAM蛋白质表达水平变化;最后,检测pc DNA3.1/TFAM和mimics NC/miR-211 mimics共转染后乳腺癌细胞增殖的增殖。结果miR-211过表达抑制TFAM蛋白质表达(P0.01),miR-211沉默促进TFAM蛋白质表达(P0.01);miR-211可靶向结合TFAM调控其表达;pc DNA3.1/TFAM可实现TFAM过表达(mRNA P0.01,蛋白质P0.01),并可恢复miR-211对TFAM的抑制作用;miR-211可抑制乳腺癌细胞的增殖和增殖(P0.05),TFAM可促进乳腺癌细胞增殖增殖(P0.01),TFAM可回复miR-211对乳腺癌细胞增殖增殖的抑制作用(P0.05)。结论 miR-211靶向TFAM基因抑制人乳腺癌细胞的增殖。     

What have we learned recently from transgenic mouse models about neurodegeneration? The most promising discoveries of this millennium

Neurodegenerative diseases are currently a major challenge in elderly care due to demographic changes and dramatic increases in the aging population worldwide. This review is focused on the most promising research discovering ways to attenuate neural loss or enhance neuroprotection and unraveling the basis of neurodegeneration using transgenic mouse models. With the recent introduction of the powerful and relatively simple gene-editing tool CRISPR-Cas9, we have entered a new era in genetic engineering that will certainly lead to a variety of new transgenic models in the near future. The aim of this review is to note the most interesting avenues addressing unmet needs in neurodegenerative disease research that could provide promising targets for both the development of new models and the study of existing ones.     

骨关节炎患者线粒体转录因子A表达与线粒体DNA拷贝数关系的研究

目的研究膝关节骨关节炎患者与正常人外周血及关节软骨细胞中的线粒体转录因子A(TFAM)表达和线粒体DNA拷贝数的关系,探讨其相关性。方法选择20例的膝关节骨关节炎患者为骨关节炎组,以正常关节软骨患者20例为对照组。各收集其外周血及关节软骨细胞,逆转录-聚合酶链反应(RT-PCR)及实时荧光PCR(SYBR GREEN I染料法)检测外周血及软骨组织中TFAM mRNA的表达水平和软骨细胞线粒体DNA拷贝数。结果骨关节炎组外周血和软骨细胞TFAM mRNA的表达量均低于正常组患者(P0.05),且二者表达量呈正相关(P0.01);骨关节炎组线粒体DNA的平均拷贝数均于正常组患者软骨细胞(P0.01),且与软骨细胞TFAM mRNA的表达量呈正相关(P0.01)。结论 TFAM通过增加其线粒体DNA拷贝数,这将可以对骨关节炎的病因提出新的解释和补充,可能为骨关节炎的检测和治疗提供新的途径。