Wnt signaling activation in the inner ear development and regeneration

2024 Fiscal Year Final Research Report

• Project/Area Number: 21K09656
• Research Category: Grant-in-Aid for Scientific Research (C)
• Allocation Type: Multi-year Fund
• Section: 一般
• Review Section: Basic Section 56050:Otorhinolaryngology-related
• Research Institution: Kyushu University
• Principal Investigator: NODA Teppei 九州大学, 医学研究院, 助教 (20707179)
• Co-Investigator(Kenkyū-buntansha): 目野 主税 九州大学, 医学研究院, 教授 (20311764) ; 安井 徹郎 九州大学, 医学研究院, 共同研究員 (60803468)
• Project Period (FY): 2021-04-01 – 2025-03-31
• Keywords: 内耳発生 / 内耳再生 / Wntシグナル / ラセン神経節ニューロン

Outline of Final Research Achievements

The auditory system lacks regenerative ability, whereas the vestibular system exhibit limited regenerative potential. The spiral ganglion neurons actively proliferate until birth but lose this ability within a week postnatally. This study investigated the role of the canonical Wnt signaling pathway as a potential regulator of these cells. Wnt signaling plays a crucial role in otic development and inner ear morphogenesis. Using reporter mice, we analyzed the activity of the Wnt pathway during inner ear developmenet. Our findings demonstrate that Wnt signaling remains active in the vestibular hair cells and in the supporting cells of both the cochlea and vestibule throughout development and into adulthood. In addition, Wnt activity was observed in spiral ganglion neurons up to 7 days after birth, coinciding with their period of proliferative potential. These findings suggest that Wnt signaling is integral to cell proliferation in the inner ear both before and after birth.

Free Research Field

耳科学

Academic Significance and Societal Importance of the Research Achievements

哺乳類の耳では、音を感じる蝸牛の有毛細胞は再生できませんが、バランスをつかさどる前庭の有毛細胞は一部再生します。ただし、蝸牛内の支持細胞には再生の可能性があり、再生医療の研究対象となっています。また、音を脳に伝える神経（らせん神経節ニューロン）も、生後すぐに増殖能力を失います。本研究では、細胞の再生や発達に関わる「Wntシグナル」という仕組みの働きをマウスで調べました。その結果、Wntシグナルは発達期から成体まで、蝸牛や前庭の支持細胞、前庭の有毛細胞、さらに出生直後の神経細胞でも活発に働いており、耳の細胞の再生や成長に重要な役割を果たしていることが示されました。