M2 macrophage exosomes reverse heart failure post-myocardial infarction by suppressing type 1 interferon signaling in...

Effective treatment strategies to alleviate heart failure that develops as a consequence of myocardial infarction (MI) remain an unmet need in cardiovascular medicine. In this study, we uncover that exosomes produced by human Tohoku Hospital Pediatrics-1 (THP-1) macrophages cultured with the cytokine interleukin-4 (THP1-IL4-exo) reverse cardiac functional decline in mice that developed MI in response to diet-induced occlusive coronary atherosclerosis. The therapeutic benefits of THP1-IL4-exo stem from their ability to drive transcriptional reprogramming of inflammatory responses in myeloid cells. Notably, repeated infusions of THP1-IL4-exo led to the suppression of type 1 interferon signaling in circulating Ly-6C^hi monocytes as well as in myeloid cells within the bone marrow and cardiac tissue. In vitro studies with primary macrophages stimulated with double-stranded DNA confirmed an ability for THP1-IL4-exo to confer suppression of type 1 interferon-mediated immune activation and inflammation. Collectively, these benefits contribute to the control of myelopoiesis, recruitment of cardiac myeloid cells, and preservation of populations of resident cardiac macrophages that together mitigate cardiac inflammation, adverse ventricular remodeling, and heart failure. Our findings introduce THP1-IL4-exo, one form of M2-macrophage exosomes, as novel anti-inflammatory and tissue repair therapeutics to preserve cardiac function post-MI.