In the auditory apparatus there are several types of neurons that are responsible for encoding the various characteristics of the sounds that the ear picks up and transmitting them to the brain, and a team of scientists from the Karolinska Institutet, in Sweden, has discovered that these auditory neurons are already present before birth in a study in mice.
Researchers have shown that during the prenatal period auditory neuron subtypes are under genetic control and have also discovered the complex molecular networks that control their origin. “Our findings demonstrate that most aspects directly related to the functional diversity of auditory neurons appear to be intrinsically molecularly defined before birth,” said Francois Lallemend, Associate Professor in the Department of Neuroscience and last author of the article published in Nature Communications. .
“This -continues the expert- has implications for how we can interpret peripheral auditory (dysfunctions) at birth, but also to devise ways to convert types of neurons in pathological conditions or congenitally deaf cochlea and hopefully improve hearing”.
Using molecular tools to restore normal hearing
“We mapped the gene expression of auditory neurons over several days of development, using a single-cell transcriptomics approach, and used advanced analytical tools to reveal a hierarchical tree of neuronal diversification,” said Saida Hadjab, Principal Investigator in the Department of Neuroscience and last co-author of the article. “We could explore in detail, at the single-cell level, the dynamics of changes in molecular development as neuron types diverged and their identities were progressively acquired.”
“Use our new knowledge and molecular tools to restore the function of auditory neurons and restore normal hearing”
“We publish the entire molecular program that defines the diversification events. We then used mouse genetics to functionally assess this program and finally compared it to published datasets of deafness genes, revealing deafness genes associated with neuronal differentiation,” he adds.
Researchers demonstrated a few years ago that neuronal diversity in the peripheral auditory system had a strong molecular basis, and this offered the possibility of manipulating each subtype in various ways to better understand their role in hearing.
The new research demonstrates the molecular programs that make up this diversity early, even before the peripheral system is active. “Our next step is to explore whether and how this diversity is affected in pathological conditions, for example after noise trauma or aging, and to use our new insights and molecular tools to restore the function of auditory neurons. and regain normal hearing,” says Francois Lallemend.
.
