Scientists at UCL Ear Institute have discovered how the inner ear’s sensory organs (which are essential for hearing and balance) take shape during early development. This research was supported by RNID.
Key research findings
The inner ear contains sensory organs that detect sound and help us keep our balance. These organs must form in the right place and stay separate for the ear to work properly.
Two researchers led the study: Ziqi Chen and Magdalena Żak, RNID-Vivensa Foundation Fellow. They found that a group of cells acts like a “fence” between the developing sensory organs. This boundary prevents the cells from mixing and helps guide the formation of other, non-sensory regions.
Two key players make this boundary work:
- Lmx1a, a gene that tells some cells to become non-sensory cells, while others go on to form sensory organs
- Actomyosin activity, a network of proteins that contract to create a physical division between cell groups
When this boundary fails – either because Lmx1a is missing or actomyosin activity is blocked – the sensory organs fuse together, disrupting normal inner ear structure.
These mechanisms are also seen in other animals, like mammals, birds, reptiles, and insects, suggesting that inner ear development is an ancient evolutionary process.
Why this discovery matters
Building the inner ear is a highly organised process. Different groups of cells must adopt specific roles and stay in the right place to form the specialised structures that allow us to hear and maintain our balance.
This study shows that the boundaries between cell groups in the inner ear are not just passive barriers – they actively coordinate how cells grow and specialise. The researchers found that these boundaries form through a combination of genetic instructions and mechanical forces: genes like Lmx1a give cells their “identity”, while actomyosin keeps them in separate zones.
Understanding these mechanisms fills an important gap in our knowledge of inner ear development and helps explain why, when these processes go wrong, the result can be hearing loss or balance problems.
What next
This discovery was made possible thanks to RNID’s supporters and funding. By deepening our understanding of how the inner ear develops, researchers can build on these foundations in future work, exploring strategies to repair or regenerate the inner ear sensory organs.
Dr Magdalena Żak, co-author of the study, said:
A better understanding of how the inner ear sensory organs develop, along with identification of the key molecular factors that control this process, enables us to replicate these mechanisms in vitro using stem cell cultures.
This approach leads to the formation of inner ear organoids, which could serve as alternatives to animal models in research. These organoids can be used to study inner ear development and diseases, ultimately facilitating the development and testing of novel therapies for hearing loss and vestibular disorders.”
For more information
This research was published in the journal eLife in November 2025.
