In the past year we have been investigating whether we are able to use genetic reprogramming techniques to generate new hair cells in the mouse cochlea. The results of this work are extremely promising: We were able to turn nonsensory cells of the mouse cochlea into hair cells. However, we consistently find that supporting cells in our mouse models do not respond to reprogramming. This is curious, as supporting cells are the cells responsible for producing new sensory hair cells in birds and fish. In the coming year, we will first examine supporting cells after our reprogramming attempts to see whether they have been able to activate any aspects of a hair cell program. Second, we will test whether hair cell death alters the adjacent supporting cells so that they become more responsive to reprogramming.