Cardiac reprogramming reduces inflammatory macrophages and improves cardiac function in chronic myocardial infarction

Area of Science:

• Cardiovascular Biology
• Regenerative Medicine
• Immunology

Background:

• Cardiomyocytes (CMs) exhibit limited regenerative capacity, leading to heart failure (HF) post-myocardial infarction (MI).
• Persistent activation of cardiac fibroblasts (CFs) and inflammatory cells contributes to cardiac remodeling and fibrosis after MI.
• Current therapies for targeting these cell types in MI remain limited.

Purpose of the Study:

• To investigate whether cardiac reprogramming reduces inflammation in infarcted hearts.
• To elucidate the mechanism by which Mef2c/Gata4/Tbx5/Hand2 (MGTH) overexpression in CFs impacts inflammatory cells.
• To assess the effect of cardiac reprogramming on inflammatory cell profiles and myocardial remodeling in chronic MI.

Main Methods:

• Single-cell RNA sequencing to analyze CF-inflammatory cell interactions in chronic MI.
• Cardiac reprogramming via MGTH overexpression in CFs.
• Fluorescence-activated cell sorting (FACS) to quantify specific inflammatory cell populations, including CCR2+ macrophages.

Main Results:

• Inflammation persists in the myocardium for up to three months post-MI and is reversible with cardiac reprogramming.
• Cardiac reprogramming suppressed pro-inflammatory gene expression in CFs and modulated cardiac macrophage populations.
• Reprogramming reduced the number of CCR2-positive inflammatory macrophages in non-infarct areas, improving myocardial remodeling.

Conclusions:

• Cardiac reprogramming effectively reduces inflammation in chronic MI by targeting CFs and inflammatory macrophages.
• The study reveals a novel mechanism by which MGTH-induced reprogramming mitigates cardiac inflammation and promotes functional recovery.
• Cardiac reprogramming represents a promising therapeutic strategy for improving outcomes after myocardial infarction.