Figure 1. Expanding the state space for cardiac fibroblast fate post-MI.

Upon injury, TCF21⁺ resident cardiac fibroblasts transition to a heterogeneous population of activated fibroblasts and myofibroblasts which are defined by the expression of Postn and αSMA stress fibers. Myofibroblast can also transition to a matrifibrocyte, which is defined by cartilage and osteogenic gene expression beinging around 2 weeks after myocardial infarction. Activated intermediates including fibroblasts which express periostin but not αSMA have been identified in vivo.