Cardiac pericytes mediate the fibrotic remodeling response to myocardial infarction

Despite the prevalence of pericytes amongst the microvasculature of the heart, the role of pericytes during ischemia-induced remodeling remains unclear. Using chondroitin sulfate proteoglycan 4 (Cspg4) lineage mouse reporters we observed pericytes migrating to the site of injury, expressing pro-fibrotic genes, and causing increased vessel leakage after myocardial infarction. Single cell RNA-sequencing of injured cardiac pericytes exhibited increased expression of genes related to vascular permeability, extracellular matrix production, basement membrane degradation and transforming growth factor-b (TGFb) signaling. Deletion of TGFb receptor 1 in Cspg4-expressing cells improved cardiac ejection fraction and reduced fibrosis post-MI. Whereas genetic ablation of Cspg4-expressing cells resulted in a rapid decline in cardiac function and increased vascular permeability following MI. Collectively, we show that cardiac pericytes participate in the post-fibrotic response after acute ischemic injury, information that will help guide the development of novel strategies to preserve vascular integrity and attenuate cardiac fibrosis. Hearts from Cspg4-CreER/+;Rosa26-tdT/+ mice were extracted and single-cell RNA sequencing was performed. Mice received either a Sham operation or an MI via LAD ligation.