ATF3 coordinates the survival/proliferation of cardiac macrophages to protect against ischemia-reperfusion injury

Cardiac resident MerTK+ macrophages exert multiple protective roles post-ischemic injury, however, the mechanisms regulating their fate are not fully understood. Here we show that GAS6-inducible transcription factor ATF3 prevents apoptosis of MerTK+ macrophages after ischemia-reperfusion (IR) injury, by repressing the transcription of multiple genes involved in type I interferon expression (Ifih1 and Infb1) and apoptosis (Apaf1). Mice lacking ATF3 in cardiac macrophages or myeloid cells showed excessive loss of MerTK+ cardiac macrophages, poor angiogenesis, and worse heart dysfunction post-IR, which were rescued by the transfer of MerTK+ cardiac macrophages. GAS6 administration improved cardiac repair in an ATF3-dependent manner. Finally, we showed a negative association of GAS6 and ATF3 expression with the risk of major adverse cardiac events in patients with ischemic heart disease. These results indicate that the GAS6-ATF3 axis has a protective role against IR injury by regulating MerTK+ cardiac macrophage survival/proliferation. Six hours after IR or sham operation, single-cell suspension of left ventricle tissues were prepared and loaded into a 10× Chromium Controller (10X Genomics). RNA from the barcoded cells was subsequently reverse-transcribed, and sequencing libraries were constructed with reagents from a 10× Chromium Single Cell 30 v2 reagent kit (10X Genomics) according to the manufacturer’s protocol. The resulting libraries were sequenced on an Illumina NovaSeq6000 platform.