A Counter Gradient of Activin A and Follistatin Instructs the Timing of Hair Cell Differentiation in the Murine Cochlea
TLDR Activin A speeds up ear hair cell differentiation, while Follistatin slows it down.
In 2019, Prajapati-DiNubila, Benito-Gonzalez, and their colleagues from the Doetzlhofer lab conducted a study on the development of the mammalian hearing organ, specifically focusing on hair cell (HC) differentiation. They used genetic mouse models and embryonic cochlear cultures to examine the counter-effects of two secreted factors, Activin A and Follistatin (FST). Their results showed that Activin A promotes HC differentiation while FST delays it. This effect was observed along the longitudinal axis and also along a radial axis. The delay in HC differentiation due to overexpression of FST was largely due to delayed cell cycle exit in the prosensory domain of the cochlea. The study concluded that a shared molecular mechanism operates both along and across the developing cochlea to regulate the timing of HC differentiation.
