microRNA-122可调节线粒体的生物发生

目的探讨microRNA-122在代谢中的作用机制。方法首先通过生物信息学预测和双荧光素酶报告基因实验去验证14个代谢相关的microRNA-122靶基因,接着分别利用瞬时转染microRNA-122前体的293A细胞、HeLa细胞和HepG2细胞去检测维持线粒体形态功能的3种标志蛋白Immt、AIF、Cox IV的含量以及通过NRF-1/2及ERR-α途径直接调控线粒体生物生成的PGC-1α的表达,并同时采用线粒体DNA定量实验和活体细胞线粒体损伤/氧化(NAO)荧光测定实验检测这些相应的细胞稳定克隆中线粒体的拷贝数。结果发现其中一些预测的线粒体生物发生相关的靶基因能被microRNA-122显著影响,并且在过表达了microRNA-122前体的不同种类的细胞中Immt、AIF和Cox IV的蛋白水平,PGC-1α的RNA水平和线粒体的拷贝数都呈现较为显著的下降。结论 mi-croRNA-122可通过调节线粒体的生物发生来影响代谢。

microRNA-122 affects the biogenesis of mitochondria

Objective Although microRNA-122 played an important role in metabolism as reported recently,the mechanism was far from clear.Method 14 metabolism related targets of microRNA-122 by bioinformatics and luciferase reporter assay were predicted and testified.Subsequently,293A,HeLa and HepG2 transient-transfected cell lines over-expressing miR-122 were used to testify the expression of three marker proteins Immt,AIF,Cox IV for mitochondrial phenotype and function and PGC-1α,which directly regulates mitochondrial biogenesis through NRF-1/2 and ERR-α pathway.Meanwhile,quantifying mitochondrial DNA and NAO assay in these stable cell clones were exploited to determine the copy number of mitochondria.Result Some mitochondrial biogenesis related targets were obviously affected by microRNA-122.And there was significant decrease for all of Immt,AIF,Cox IV in protein level,PGC-1α in RNA level and the copy number of mitochondria in different kinds of microRNA-122 over-expression cell systems.Conclusion MicroRNA-122 can affect metabolism through regulating the biogenesis of mitochondria.