Canonical Wnt Signaling Pathway on Polarity Formation of Utricle Hair Cells.

Di Deng,Dongdong Ren,Xiaoyu Yang,Yanmei Wang,Yu Zhao,Yibo Huang,Xiaoqing Qian,Fanglu Chi,Binjun Chen,Renjie Chai

doi:10.1155/2021/9950533

Abstract

As part of the inner ear, the vestibular system is responsible for sense of balance, which consists of three semicircular canals, the utricle, and the saccule. Increasing evidence has indicated that the noncanonical Wnt/PCP signaling pathway plays a significant role in the development of the polarity of the inner ear. However, the role of canonical Wnt signaling in the polarity of the vestibule is still not completely clear. In this study, we found that canonical Wnt pathway-related genes are expressed in the early stage of development of the utricle and change dynamically. We conditionally knocked out β-catenin, a canonical Wnt signaling core protein, and found that the cilia orientation of hair cells was disordered with reduced number of hair cells in the utricle. Moreover, regulating the canonical Wnt pathway (Licl and IWP2) in vitro also affected hair cell polarity and indicated that Axin2 may be important in this process. In conclusion, our results not only confirm that the regulation of canonical Wnt signaling affects the number of hair cells in the utricle but also provide evidence for its role in polarity development.

Highlights

The cochlea and vestibule are important for hearing and balance, respectively
The stereocilia are arranged in an ascending cluster, with the highest being located adjacent to the kinocilium [6, 7]
hair cells (HCs) are oriented such that their stereociliary bundles point toward the line of polarity reversal (LPR) in the mammalian utricle

Summary

Introduction

The cochlea and vestibule are important for hearing and balance, respectively. They detect sound and position signals through stereociliary bundle on the surface of hair cells (HCs) [1,2,3,4]. The vestibular system contains utricular maculae, saccular maculae, and three semicircular canal cristae. Planar polarity of the stereociliary bundle guarantees that the range of motion is detected properly by vestibular HCs [5]. The direction of stereociliary bundle between adjacent HCs are highly similar. The maculae are divided into two regions: the kinocilium of the utricular maculae faces the LPR, while the kinocilium of the saccular maculae points away from the LPR [8]

Objectives

Findings

Discussion

Conclusion