A Counter Gradient of Activin A and Follistatin Instructs the Timing of Hair Cell Differentiation in the Murine Cochlea

In 2019, a study investigated the role of Activin A and follistatin in hair cell differentiation in the murine cochlea. The researchers discovered that a counter gradient of these two proteins instructs the timing of hair cell differentiation. High levels of Activin A promoted early differentiation, while high levels of follistatin delayed it. The study also found that follistatin overexpression resulted in the formation of additional inner hair cells and delayed hair cell maturation. The findings suggest that follistatin antagonizes hair cell differentiation in an Activin A-dependent manner. The study concluded that Activin A and follistatin play key roles in timing hair cell differentiation and regulating the cell cycle withdrawal of pro-sensory cells in the developing murine cochlea.