Research ArticleBIOPHYSICS

Cochlear outer hair cell horizontal top connectors mediate mature stereocilia bundle mechanics

See allHide authors and affiliations

Science Advances  20 Feb 2019:
Vol. 5, no. 2, eaat9934
DOI: 10.1126/sciadv.aat9934


Outer hair cell (OHC) stereocilia bundle deflection opens mechanoelectrical transduction channels at the tips of the stereocilia from the middle and short rows, while bundle cohesion is maintained owing to the presence of horizontal top connectors. Here, we used a quantitative noncontact atomic force microscopy method to investigate stereocilia bundle stiffness and damping, when stimulated at acoustic frequencies and nanometer distances from the bundle. Stereocilia bundle mechanics were determined in stereocilin-deficient mice lacking top connectors and with detached tectorial membrane (Strc−/−/Tecta−/− double knockout) and heterozygous littermate controls (Strc+/−/Tecta−/−). A substantial decrease in bundle stiffness and damping by ~60 and ~74% on postnatal days P13 to P15 was observed when top connectors were absent. Additionally, we followed bundle mechanics during OHC top connectors development between P9 and P15 and quantified the observed increase in OHC bundle stiffness and damping in Strc+/−/Tecta−/− mice while no significant change was detected in Strc−/−/Tecta−/− animals.

This is an open-access article distributed under the terms of the Creative Commons Attribution-NonCommercial license, which permits use, distribution, and reproduction in any medium, so long as the resultant use is not for commercial advantage and provided the original work is properly cited.

View Full Text

Stay Connected to Science Advances