阐明间充质干细胞牙向分化的功能和机制是提高生物牙根成功率的关键。miRNA在细胞分化过程中有着重要作用。课题组前期发现miR615-3p和下游基因FBLN1可能具有调控间充质干细胞牙向分化的能力；miR615-3p通过与FBLN1的3’UTR端结合负向调控FBLN1。但是miR615-FBLN1信号通路对间充质干细胞牙向分化和生物牙根再生的功能和调控机制不清。在此基础上，本课题拟利用获得性和丧失性功能研究阐明miR615-3p及FBLN1对间充质干细胞牙向分化的作用；通过生物信息学、RNA pull-down、RIP、生物素标记miRNA共沉淀等技术明确与miR615-3p结合的circRNA，及二者的相互作用；利用生物信息学、荧光素酶报告基因、CHIRP、qRT-PCR等方法揭示miR615-3p对FBLN1的表观遗传调控机制。本课题为促进生物牙根再生提供理论依据和候选靶点。

Elucidating the function and underlying mechanism of dentinogenic differentiation in mesenchymal stem cells is the key to improve the success of bio-root regeneration. miRNAs are found involving in cells differentiation. Our previous studies find that miR615-3p and the downstream gene FBLN1 may own the ability of regulating dentinogenic differentiation of mesenchymal stem cells. miR615-3p negatively regulates the FBLN1 by directly targets 3 'UTR of FBLN1. However, the detailed function and underlying mechanism of miR615-FBLN1 signaling pathway on mesenchymal stem cells mediated dentinogenesis and bio-root regeneration are still unclear. Based on the data, the loss/gain function studies are to investigate whether miR615-3p and FBLN1 participate in modulating the dentinogenic differentiate capacity of mesenchymal stem cells in vitro and in vivo. Moreover, informatics analysis, cell fractionation assay, RNA pull-down, RIP-qPCR, and luciferase assay are used to identify the circRNA binding to miR615-3p, and the interaction between miR615-3p and circRNA. Furthermore, informatics analysis, CHIRP, luciferase assay, and qRT-PCR are used to reveal the regulation mechanism of miR615-3p on FBLN1. This study will help us to discover the molecular regulation mechanism of miR615-FBLN1 signaling pathway in dentinogenic differentiation of mesenchymal stem cells, and provide theoretical basis and candidate target for bio-root regeneration.