A new genetic study could help find revolutionary treatment for hearing loss that occurs due to impairment of hair cells responsible for auditory functioning. The details of the study have appeared in the periodical ‘eLife’. The researchers tried to analyze the development of hair cells and their replacement in case of damage; as according to them any issues with them or the nerves connecting them to the brain played a large role in hearing loss.
The working of outer and inner hair cells which coat the curved hollow called the cochlea in the inner ear determines detection of sound. The growth of these hair cells during the development of the embryo is a very complex process. Researchers have gathered a lot of information on development of hair cells yet the detailed working of molecular signals that determine hearing was not very clear. For better understanding, the researchers looked closely at the development of cochlea in mouse embryos. In the process they realized that two proteins called follistatin and Activin A, played a major role in the formation of hair cells as their levels altered while precursor cells developed into mature hair cells within the cochlea. The proteins exhibited varying levels based on the location and timing of the formation pattern.
The change from high to low levels of the proteins was referred to as signaling gradients by the researchers. The signaling gradient of Activin A followed an inward moving wave path while that of follistatin followed an outward moving wave path. The detailed and highly accurate growth of hair cells was controlled by the two proteins by functioning in opposite ways. Any disruption in the precisely timed action of the two proteins would cause an adverse impact on the cochlea’s organization. The study findings were confirmed after testing them out in genetically engineered and normal mice. Researchers are hopeful that the study results could help find a remedy for hearing loss caused due to hair cell loss.