Postnatal Changes of Neural Stem Cells in the Mammalian Auditory Cortex

Zhengqing Hu,Li Tao,Meng Deng

doi:10.3390/ijms22041550

Abstract

Our previous study reported neural stem cells (NSCs) in the auditory cortex (AC) of postnatal day 3 (P3) mice in vitro. It is unclear whether AC-NSCs exist in vivo. This study aims to determine the presence and changes of AC-NSCs during postnatal development and maturation both in vitro and in vivo. P3, postnatal day 14 (P14), 2-month-old (2M), and 4-month-old (4M) mouse brain tissues were fixed and cryosectioned for NSC marker immunostaining. In vitro, P3, P14, and 2M AC tissues were dissected and cultured in suspension to study NSCs. NSC proliferation was examined by EdU incorporation and cell doubling time assays in vitro. The results show that Nestin and Sox2 double expressing NSCs were observed in the AC area from P3 to 4M in vivo, in which the number of NSCs remarkably reduced with age. In vitro, the neurosphere forming capability, cell proliferation, and percentage of Nestin and Sox2 double expressing NSCs significantly diminished with age. These results suggest that AC-NSCs exist in the mouse AC area both in vitro and in vivo, and the percentage of AC-NSCs decreases during postnatal development and maturation. The results may provide important cues for the future research of the central auditory system.

Highlights

In the auditory system, the sound is captured and converted into auditory signals in the ear, which is transferred to the central auditory system, including the auditory cortex (AC)
Our previous reports showed that the AC tissue was harvested from the postnatal mouse brain, and AC-neural stem cells (NSCs) were identified in the culturing of these tissues [26]
AC-NSCs were identified in the postnatal day 3 (P3) mouse brain, and these NSCsInweoruerapbrleevtiooubes creupltourrte,dAiCn-vNitSrCos[2w6]e.rIenidtheinstsifitueddyi,nPt3h, eP1P43, m2Mou, asendbr4aMin,maonudsethAesCe tNtiisssSsuCueessswwweeerrereeassbttulueddtioieeddbeffoocrurtlththueerpepdrreeissneennvccieteroooff[N2N6SS].CCIssniintnhvivsiivvsotou..dTTyhh,eePNN3,SSPCC14mm, a2arMrkke,erarssnSdSoo4xxM22aamnndoduNNseeessAttiinCn double-positive cells were found in the mouse AC sections from P3 to 4M, suggesting the presence of NSCs in the mouse AC area in vivo

Summary

Introduction

The sound is captured and converted into auditory signals in the ear, which is transferred to the central auditory system, including the auditory cortex (AC). The peripheral auditory system is vulnerable to a variety of insults, including sound overstimulation, genetic disorder, ototoxic drugs, and trauma, which usually leads to irreversible damage to hair cells and spiral ganglion neurons to cause hearing impairment [1,2,3]. Extensive efforts have been focused on the regeneration of the peripheral auditory system, including hearing aids, cochlear implants, stem cell-based replacement, gene therapy, and stria vascularis regeneration [4,5,6,7,8,9,10,11,12,13]. The central auditory system can be damaged by degeneration secondary to the peripheral auditory system injury. It is currently unclear whether the central auditory system can be regenerated following injuries, which is an understudied area

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