Initiation and formation of stereocilia during the development of mouse cochlear hair cells
- 1National Centre for Biological Sciences, Tata Institute for Fundamental Research, Bangalore, India
- 2Instituto de Nanociencia y Materiales de Aragón (INMA), CSIC-Universidad de Zaragoza and CIBER-BBN, Zaragoza, Spain
- 3Fundación Agencia Aragonesa Para la Investigación y el Desarrollo (ARAID), Zaragoza, Spain
Abstract
IntroductionStereocilia are apically located actin-protrusions of inner-ear hair cells that form graded staircase-like bundles essential for mechanosensation. Although stereocilia morphogenesis has been described in several species, quantitative analysis of this process in the mouse cochlea remains limited, and previous studies have relied largely on scanning electron microscopy.MethodsHere, we combined scanning electron microscopy and fluorescence microscopy to characterise hair cell apical surface development and stereocilia formation in the mouse organ of Corti from early specification through postnatal development.ResultsBefore hair cell differentiation, sensory progenitors exhibit a dense lawn of microvilli on their apical surface. Hair cell differentiation is accompanied by progressive remodeling of the apical surface, beginning with enrichment of junctional actin, followed by eccentric relocalisation of the kinocilium, microvillar blooming, and selective thickening of microvilli proximal to the kinocilium. These morphological changes are followed by further protrusion widening, row specialisation, and progressive microvillar resorption during postnatal bundle maturation. To quantitatively characterise the spatial organisation of F-actin during these transitions, we developed an unbiased normalized radial projection analysis (UN-RaPA), which maps relative actin filament distribution across individual cells while accounting for differences in cell shape, size and orientation. This approach enables comparison of actin signatures across developmental stages and cell types and can be extended to additional fluorescence channels. Using this multichannel capability, we mapped the spatial distributions of the actin-associated proteins Ezrin and Radixin onto developmental actin signatures, revealing distinct patterns associated with different stages of hair-cell and stereocilia development.Discussion and ConclusionTogether, our imaging and quantitative analysis framework defines developmental changes in the hair-cell apical surface and provides a quantitative approach for relating the spatial distribution of actin-associated proteins to morphological progression during stereocilia formation.
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BibTeX
@article{chakravarthy2026initiation,
title = {{Initiation and formation of stereocilia during the development of mouse cochlear hair cells}},
author = {Suraj Ranganath Chakravarthy and Raj K. Ladher and Thomas S. van Zanten and Thomas S. van Zanten},
journal = {Frontiers in Cell and Developmental Biology},
year = {2026},
month = oct,
doi = {10.3389/fcell.2026.1928332},
url = {https://doi.org/10.3389/fcell.2026.1928332},
note = {CC BY},
}
RIS
TY - JOUR
TI - Initiation and formation of stereocilia during the development of mouse cochlear hair cells
AU - Suraj Ranganath Chakravarthy
AU - Raj K. Ladher
AU - Thomas S. van Zanten
AU - Thomas S. van Zanten
PY - 2026
DA - 2026/10/23
JO - Frontiers in Cell and Developmental Biology
DO - 10.3389/fcell.2026.1928332
UR - https://doi.org/10.3389/fcell.2026.1928332
AB - IntroductionStereocilia are apically located actin-protrusions of inner-ear hair cells that form graded staircase-like bundles essential for mechanosensation. Although stereocilia morphogenesis has been described in several species, quantitative analysis of this process in the mouse cochlea remains limited, and previous studies have relied largely on scanning electron microscopy.MethodsHere, we combined scanning electron microscopy and fluorescence microscopy to characterise hair cell apical surface development and stereocilia formation in the mouse organ of Corti from early specification through postnatal development.ResultsBefore hair cell differentiation, sensory progenitors exhibit a dense lawn of microvilli on their apical surface. Hair cell differentiation is accompanied by progressive remodeling of the apical surface, beginning with enrichment of junctional actin, followed by eccentric relocalisation of the kinocilium, microvillar blooming, and selective thickening of microvilli proximal to the kinocilium. These morphological changes are followed by further protrusion widening, row specialisation, and progressive microvillar resorption during postnatal bundle maturation. To quantitatively characterise the spatial organisation of F-actin during these transitions, we developed an unbiased normalized radial projection analysis (UN-RaPA), which maps relative actin filament distribution across individual cells while accounting for differences in cell shape, size and orientation. This approach enables comparison of actin signatures across developmental stages and cell types and can be extended to additional fluorescence channels. Using this multichannel capability, we mapped the spatial distributions of the actin-associated proteins Ezrin and Radixin onto developmental actin signatures, revealing distinct patterns associated with different stages of hair-cell and stereocilia development.Discussion and ConclusionTogether, our imaging and quantitative analysis framework defines developmental changes in the hair-cell apical surface and provides a quantitative approach for relating the spatial distribution of actin-associated proteins to morphological progression during stereocilia formation.
SN - 2296-634X
ER -