联合调控Shh和Wnt/β-catenin信号通路促进小鼠耳蜗毛细胞再生的作用及其机制研究

哺乳动物耳蜗毛细胞不能自发再生，一旦毛细胞丢失将造成永久性耳聋。激活耳蜗毛细胞再生是治疗感音神经性聋的理想途径。Shh和Wnt/β-catenin信号在胚胎期内耳前体细胞的增殖、分化和命运决定过程中发挥重要作用。毛细胞损伤后在新生小鼠耳蜗支持细胞中单上调Wnt/β-catenin信号能够促进前体细胞增殖，但增殖细胞分化为毛细胞的比例很低；而单上调Shh信号时虽然增殖细胞较少，但增殖细胞分化为毛细胞的比例较高。本项目拟在前期工作基础上，借助Shh和Wnt/β-catenin信号条件性基因高表达小鼠，结合Shh和Wnt信号的激动剂和抑制剂，研究联合调控Shh和Wnt/β-catenin信号对新生小鼠内耳前体细胞和耳蜗毛细胞再生的作用。拟采用高通量测序方法分析耳蜗前体细胞基因表达水平，阐明联合调控Shh和Wnt/β-catenin信号促进毛细胞再生的机制，为感音神经性耳聋的防治提供实验依据。

Unlike lower vertebrates, mammalian cochlear hair cells cannot regenerate spontaneously after damage, although the vestibular system maintains limited hair cell regeneration capacity. As a result, hair cell loss is the major cause of permanent sensorineural hearing loss. In situ cochlear hair cell regeneration should be explored as one of the main approaches to restore hearing that is lost due to hair cell loss. Shh and Wnt/β-catenin signaling play important roles in the proliferation, differentiation, and cell fate decision of embryonic inner ear progenitor cells. Our in vitro experiment study showed that Shh could effectively promote the proliferation and differentiation of mouse neonatal Lgr5 positive progenitor cells. Up-regulation of Wnt/beta-catenin signal in mouse neonatal cochlear support cells could promote precursor cells to proliferate, but a very low proportion of the proliferating cells differentiated into hair cells, and while up-regulation of Shh signaling induced few proliferating cells, but the higher percentage of proliferating cells differentiated into hair cells. In this project, we aim to explore whether co-regulation of Shh and Wnt signaling could promote cochlear hair cell regeneration by using transgenic mice, agonists, and antagonists of Shh and Wnt/β-catenin signaling. The mechanism of hair cell regeneration and the interaction of Shh and Wnt signaling will also be investigated. This study has important scientific value and application prospect for the treatment of sensorineural hearing loss by providing experimental evidence.