By copying genetic pathways found in fish and chickens, researchers have been able to regenerative auditory hair cells in mice
Humans and mice have sadly lost the ability to regenerate auditory cells, which are gradually lost after exposure to illness, chemotherapy, noise and general aging. Thankfully, some animals such as fish and chickens do retain this ability - providing us with a helpful template for research.
By copying pathways found in those animals, a group of scientists from St. Jude Children's Research Hospital have succeeded in restoring these cells in adult mice. After monitoring these creatures which are able to regenerate these cells, the team discovered that this process was triggered by downregulation of the protein p27 in conjunction with upregulation of Atoh1. Through their research they isolated 4 proteins involved in a regeneration pathway: GATA3 and POU4F3 along with p27 and ATOH1. On closer analysis they determined that POU4F3 and Atoh1 were most crucial to the hair cell regeneration signalling. Atoh1 is a known transcription factor responsible for auditory hair cell development, but after birth this signal is sadly switched off permanently in mammals - blocking the regeneration process.
"Work in other organs has shown that reprogramming cells is rarely accomplished by manipulating a single factor. This study suggests that supporting cells in the cochlea are no exception and may benefit from therapies that target the proteins identified in this study. This study suggests that targeting p27, GATA3 and POU4F3 may enhance the outcome of gene therapy and other approaches that aim to restart ATOH1 expression"
While these were specially bred mice which were easier to genetically manipulate, the study certainly raises hope that endogenous signalling pathways in humans could be reactivated through various approaches to trigger hearing renewal.
Read more at MedicalXpress