Cardiac pericytes mediate the remodeling response to myocardial infarction

Area of Science:

• Cardiovascular Biology
• Cellular Biology
• Regenerative Medicine

Background:

• Cardiac pericytes are abundant in heart microvasculature but their function post-myocardial infarction (MI) is poorly understood.
• Ischemia-induced cardiac remodeling involves complex cellular and molecular changes affecting vascular integrity and tissue repair.

Purpose of the Study:

• To elucidate the role of cardiac pericytes in the pathological remodeling of the heart following myocardial infarction (MI).
• To investigate the molecular mechanisms by which pericytes contribute to fibrosis and vascular dysfunction after ischemic injury.

Main Methods:

• Utilized multiple lineage-tracing mouse models to track pericyte behavior after MI.
• Performed single-cell RNA sequencing (scRNA-Seq) on cardiac pericytes at different time points post-MI.
• Genetically manipulated TGF-β receptor 1 and Cspg4-expressing cells to assess functional consequences.

Main Results:

• Pericytes migrated to the MI site, expressed profibrotic genes, and correlated with increased vascular leakage.
• scRNA-Seq identified temporally regulated gene expression in pericytes related to vascular permeability, ECM remodeling, and TGF-β signaling.
• Deletion of TGF-β receptor 1 in Cspg4+ cells reduced fibrosis and transiently improved ejection fraction.
• Genetic ablation of Cspg4+ cells led to exacerbated vascular permeability, cardiac dysfunction, and increased mortality.

Conclusions:

• Cardiac pericytes play a critical role in regulating vascular homeostasis and fibrotic responses after acute ischemic injury.
• Pericyte-derived TGF-β signaling is crucial for controlling cardiac fibrosis post-MI.
• Understanding pericyte function offers potential therapeutic targets for preserving vascular integrity and mitigating adverse cardiac remodeling.