Mechanical regulation of macrophage metabolism by allograft inflammatory factor 1 leads to adverse remodeling after cardiac injury.

Myocardial infarction (MI) mobilizes macrophages, the central protagonists of tissue repair in the infarcted heart. Although necessary for repair, macrophages also contribute to adverse remodeling and progression to heart failure. In this context, specific targeting of inflammatory macrophage activation may attenuate maladaptive responses and enhance cardiac repair. Allograft inflammatory factor 1 (AIF1) is a macrophage-specific protein expressed in a variety of inflammatory settings, but its function after MI is unknown. Here we identify a maladaptive role for macrophage AIF1 after MI in mice. Mechanistic studies show that AIF1 increases actin remodeling in macrophages to promote reactive oxygen species-dependent activation of hypoxia-inducible factor (HIF)-1α. This directs a switch to glycolytic metabolism to fuel macrophage-mediated inflammation, adverse ventricular remodeling and progression to heart failure. Targeted knockdown of Aif1 using antisense oligonucleotides improved cardiac repair, supporting further exploration of macrophage AIF1 as a therapeutic target after MI.