Myofibroblasts accumulate in the spaces between organ structures and produce
extracellular matrix (ECM) proteins, including collagen I. They are the primary “effector” cells
in tissue remodeling and fibrosis. Previously, leukocyte progenitors termed fibrocytes and
myofibroblasts generated from epithelial cells through epithelial-to-mesenchymal transition
(EMT) were considered the primary sources of ECM-producing myofibroblasts in injured
tissues. However, genetic fate mapping experiments suggest that mesenchyme-derived …