Runx1 in Postn-Expressing Fibroblasts But Not Cardiomyocytes Exacerbates Adverse Cardiac Remodeling Post-Myocardial Infarction.

Runx1 is strongly induced in the heart after acute injury and in chronic disease settings. Its expression negatively correlates with outcomes, and past work demonstrates a protective effect when Runx1 is inhibited through a variety of experimental means. We sought to establish which Runx1-expressing cell type(s) are responsible for the adverse remodeling phenotypes observed upon its induction. Using distinct Cre drivers, we ablated Runx1 from cardiomyocytes and fibroblasts. Following experimental myocardial infarction, we established that loss of Runx1 in fibroblasts, but not cardiomyocytes, is able to protect from adverse remodeling.