Hedgehog actively maintains adult lung quiescence and regulates repair and regeneration

It is generally thought that the quiescence of tissue is not actively maintained, but rather a state reflecting the absence of proliferative signal; here the authors find that quiescence is actively maintained by paracrine hedgehog signalling provided by the epithelium in the mouse adult lung, and that hedgehog is dynamically regulated during injury repair and resolution for proper restoration of tissue homeostasis after injury.