Regulators of cardiac fibroblast cell state

Fibroblasts are the primary regulator of cardiac extracellular matrix (ECM). In response to disease stimuli car-diac fibroblasts undergo cell state transitions to a myofibroblast phenotype, which underlies the fibrotic response in the heart and other organs. Identifying regulators of fibroblast state transitions would inform which pathways could be therapeutically modulated to tactically control maladaptive extracellular matrix remodeling. Indeed, a deeper understanding of fibroblast cell state and plasticity is necessary for controlling its fate for therapeutic benefit. p38 mitogen activated protein kinase (MAPK), which is part of the noncanonical trans-forming growth factor 8 (TGF8) pathway, is a central regulator of fibroblast to myofibroblast cell state transi-tions that is activated by chemical and mechanical stress signals. Fibroblast intrinsic signaling, local and global cardiac mechanics, and multicellular interactions individually and synergistically impact these state transitions and hence the ECM, which will be reviewed here in the context of cardiac fibrosis. (c) 2020 Elsevier B.V. All rights reserved.