Understanding myofibroblast origin in the fibrotic lung

Idiopathic pulmonary fibrosis (IPF) is characterized by accumulation of myofibroblasts (MYFs) and extracellular matrix components, which leads to severe distortion and scarring of the gas exchange units of the lung, the alveoli, and ultimately respiratory failure. Fibrosis-associated MYFs are therefore widely regarded as the culprits that compromise the architectural makeup of the lung in fibrotic disease. During the past decade, the cellular source of MYFs has been intensely investigated. The rationale for such studies is that identifying the origin of these cells might help identify novel therapeutic targets and candidates to treat IPF patients. Recent advances in basic and translational research employing lineage tracing and multi-omics approaches have helped address the identity of MYF precursors, highlight the underlying heterogeneity, and to a less extent investigate MYF fate during fibrosis resolution. In this review, we discuss the current understanding of such important aspects of MYF biology as well as recent developments in the treatment of IPF.