A checkerboard pattern of inner ear cells enables us to hear

A Japanese research group has become the first to reveal that the checkerboard-like arrangement of cells in the inner ear’s organ of Corti is vital for hearing. The discovery gives a new insight into how hearing works from the perspective of cell self-organization and will also enable various hearing loss disorders to be better understood.

The research group included Assistant Professor TOGASHI Hideru of Kobe University’s Graduate School of Medicine and Dr. KATSUNUMA Sayaka of Hyogo Prefectural Kobe Children’s Hospital.

These research results were published online in Frontiers in Cell and Developmental Biology on December 8, 2022.

Main Points

In the organ of Corti in the inner ear, there are two types of cells arranged in a checkerboard-like mosaic pattern; hair cells responsible for hearing and their support cells. However, the relationship between this checkerboard pattern and hearing function has long remained unclear.
In mice in which the cells in the organ of Corti could not form into this checkerboard pattern, only the hair cells died (apoptosis), which resulted in deafness.
For the first time in the world, it was understood that the checkerboard layout plays a fundamental structural role in preserving hair cells and their functionality as the arrangement prevents hair cells from adhering to each other.
This mosaic pattern of cells has been observed in various sensory organs in many different kinds of animals. Understanding the mechanism behind how cell self-organization forms these mosaic patterns will help illuminate the functions of a variety of sensory organs and the mechanisms behind disorders.

Research Background

The inner ear cochlea is necessary for hearing sound, and located inside it is the organ of Corti (*1). When the organ of Corti is viewed from above under a microscope, two types of cells arranged in a precisely ordered layout resembling a chess or checkerboard can be seen. Hair cells that convey sound waves to the brain are separated by support cells, which prevent the hair cells from touching each other. Although it has been thought that this checkerboard arrangement is necessary for the organ of Corti to function properly, the relationship between this pattern and hearing function has long remained unclear.

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