本项目以miRNA为视角，沿着miR-140-5p靶向作用LIFR的思路，朝着阐述miR-140-5p调控成脂分化机制的目标开展工作。研究分体内和体外二部分，体外试验以人类骨髓间充质干细胞成脂分化过程为对象，应用定量PCR、慢病毒介导的RNAi和免疫印迹等技术证实miR-140-5p靶向作用于LIFR这一预实验结果，采用上\下调miR-140-5p表达的方法验证LIFR是miR-140-5p的靶基因，并用荧光素酶报告系统鉴定靶位点；通过改变miR-140-5p、LIFR表达，检测JAK2-STAT3信号通路、成脂表型及成脂特征基因表达。体内试验将miR-140-5p和LIFR表达水平不同的hMSCs植入裸鼠皮下，获取新生组织采用与体外相同的评价指标，从体内和体外二方面阐述miR-140-5p靶向作用LIFR经JAK2-STAT3通路调控成脂分化的机制，为认识和治疗骨质疏松提供新的理论依据。

The research aims to demonstrate that the mechanisms of miR-140-5p targeting on LIFR in adipogenic differentitation. This study is divided into two parts (in vitro and vivo). It will be as an object of study that human bone marrow mesenchymal stem cells differentiate into adipoctyes in vitro. We will confirm the pre-experiments results that miR-140-5p target on the LIFR by real time quantitative PCR,lentiviral-mediated RNAi and western-blotting. Then we identify miR-140-5p target gene is LIFR by up\down regulation of miR-140-5p expression and further confirm the target sites by dual luciferase system.Subsequently,we analysis the JAK2-STAT3 signal pathway, the adipogenic phenotype and the gene expression of adipogenic characteristics by up\down regulation of miR-140-5p and LIFR expression. In vivo, miR-140-5p and LIFR of the different gene expression level are implanted in the nude mice subcutaneous where adipogenic differentitation will happen. After the newborn subcutaneous adipose tissue will be removed. We also make a analysis using the same assessment methods adopted in vitro. In this way, we can further clarify the regulatory mechanisms of adipogenic differentiation which miR-140-5p target on LIFR through JAK2-STAT2 signaling pathway in vitro and vivo experiments. It will provide a new theoretical basis for profound understanding and effective treatment of osteoporosis.