Wnt和FoxG1协同调控Lgr5+内耳干细胞再生毛细胞的研究

感音神经性聋主要是耳蜗毛细胞不可逆损失造成的。申请人前期研究发现内耳中Lgr5阳性细胞是内耳干细胞，激活Wnt信号能促进其增殖，但单独调控Wnt信号促进毛细胞再生的效果不显著，需要通过多种信号协同调控来有效促进毛细胞再生。FoxG1是Wnt上游调控信号，也与BMP，Notch，Shh等多种信号通路有相互作用。目前FoxG1在毛细胞再生中的作用以及对内耳干细胞的调控机制都不清楚。本项目将系统研究Wnt和FoxG1对内耳干细胞的协同调控机制，拟通过两种信号协同调控促进内耳干细胞再生有功能的毛细胞。拟实现目标：一、在正常小鼠中研究FoxG1对内耳干细胞的调控作用；二、在毛细胞损伤模型中研究FoxG1在毛细胞再生中的作用；三、研究通过两种信号协同调控促进内耳干细胞再生毛细胞；四、研究两种信号协同调控后新生毛细胞功能及小鼠听觉功能的情况。本项目将为临床上通过内耳干细胞治疗听力损失奠定理论和实验基础。

The main reason for sensorineural hearing loss is the irreversible loss of sensory hair cells. My previous studies have reported the Wnt responsive Lgr5+ cells are inner ear stem cells, and activation of Wnt signals can promote the proliferation of these inner ear stem cells, and a small part of these Lgr5+ inner ear stem cells can regenerate hair cells. However, regulation of the Wnt signaling pathway alone fails to significantly promote the hair cell regeneration; thus the co-regulation of several signaling pathways is needed to significantly promote the hair cell regeneration after hair cell loss. FoxG1 is a transcription factor upstream of Wnt signaling, and has been reported to have interaction with multiply signaling pathways, including BMP，Notch and Shh. However, in mice cochlea, the role of FoxG1 in hair cell regeneration and in regulating the Lgr5+ inner ear stem cells remain uninvestigated. This project has been designed to systematically investigate the co-regulation mechanism of Wnt and FoxG1 in regulating the Lgr5+ inner ear stem cells with or without hair cell injury; with the goal to promote the regeneration of functional hair cells from Lgr5+ inner ear stem cells though the co-regulation of Wnt and FoxG1 signaling pathways. In this project we propose to fulfill the following aims: Aim1: we will investigate the role of FoxG1 in regulating the inner ear stem cells in undamaged mice cochlea both in vitro and in vivo; Aim2: In hair cell damage model, we will investigate how FoxG1 regulate the inner ear stem cells to promote hair cell regeneration both in vitro and in vivo; Aim3: we will investigate how the co-regulation of Wnt and FoxG1 signaling promote the inner ear stem cells to regenerate the functional hair cells; Aim4: After co-regulation of Wnt and FoxG1 signaling, we will investigate the function of new regenerated hair cells originated from inner ear stem cells and test the correlative recovery of hearing function by ABR and DPOAE. The goal of this study is to establish the theory and experimental foundation for the clinical treatment of sensorineural hearing loss by stem cell therapy.