Pericytes exhibit a parallel pro-fibrotic response after vascular injury in the heart and brain

Ischemic injury leads to irreversible loss of neurons and cardiomyocytes in the brain and heart, respectively which ultimately results in fibrotic scar formation. Despite recent advances in tissue fibrosis, cellular mediators of scar formation in the heart and brain remain elusive. Pericytes are a heterogeneous population of mural cells that surround microvessels in various organs including the brain and heart. Their function beyond vascular integrity and contractility is poorly understood, although recent studies have suggested they may be a major contributor to tissue fibrosis. In both the heart and brain, differences in injury models, lack of proper transgenic mouse models for lineage tracing and absence of pericyte-specific markers have contributed to discrepancies in the literature regarding their direct contributions to fibrosis. Here, by performing a set of complementary experiments using a common pericyte transgenic model and clinically-relevant ischemic injury models of stroke and myocardial infarction, we demonstrated the parallel pro-fibrotic response of pericyte after vascular injury.