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Updated: Jul 16, 2025

Dextran Labeling and Uptake in Live and Functional Murine Cochlear Hair Cells
Published on: February 8, 2020
mTORC2 regulates auditory hair cell structure and function
Maurizio Cortada1, Soledad Levano1, Michael N Hall2
1Department of Biomedicine, University of Basel, CH-4031 Basel, Switzerland.
Abstract:
mTOR broadly controls cell growth, but little is known about the role of mTOR complex 2 (mTORC2) in the inner ear. To investigate the role of mTORC2 in sensory hair cells (HCs), we generated HC-specific Rictor knockout (HC-RicKO) mice. HC-RicKO mice exhibited early-onset, progressive, and profound hearing loss. Increased DPOAE thresholds indicated outer HC dysfunction. HCs are lost, but this occurs after hearing loss. Ultrastructural analysis revealed stunted and absent stereocilia in outer HCs. In inner HCs, the number of synapses was significantly decreased and the remaining synapses displayed a disrupted actin cytoskeleton and disorganized Ca2+ channels. Thus, the mTORC2 signaling pathway plays an important role in regulating auditory HC structure and function via regulation of the actin cytoskeleton. These results provide molecular insights on a central regulator of cochlear HCs and thus hearing.
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