Hypoxia is associated with tissue injury and fibrosis but its functional role in fibroblast
activation and tissue repair/regeneration is unknown. Using kidney injury as a model
system, we demonstrate that injured epithelial cells produce an increased number of
exosomes with defined genetic information to activate fibroblasts. Exosomes released by
injured epithelial cells promote proliferation, α-smooth muscle actin expression, F-actin
expression, and type I collagen production in fibroblasts. Fibroblast activation is dependent …