Mitochondria are a critical metabolic control mechanism for orchestrating phase-specific repair behaviors in wound macrophages

Here we demonstrate that skin injury induces different metabolic programs in wound macrophages by profiling their early versus late stages at both the transcriptional and functional levels. We show that glycolytic metabolism in early phase wound macrophages is not sufficient to ensure a productive repair response. Instead, combining conditional disruption of the electron transport chain in myeloid cells by deletion of mitochondrial aspartyl-tRNA synthetase (DARS2) with single cell sequencing analysis of wound macrophages, we found that at early stage a defined subpopulation of macrophages requires repurposing of mitochondrial activity to initiate a cascade of mitochondrial ROS production, HIF1a stabilization, ultimately driving an effective pro-angiogenic transcriptional program essential for timely healing. In contrast, to convey late phase wound macrophages into repair mode they depend on IL-4Ra-mediated mitochondrial respiration and so far unknown regulation of mitohormesis. Collectively, we identify mitochondria as critical metabolic control mechanism for wound macrophage effector functions. BMDMs form WT and Dars2 KO animals were seeded in 12-well plates (Sigma-Aldrich) in a density of 250,000 cells/cm2 in growth medium. Cells were stimulated with IL-4 + IL-13 (50 ng/mL each) or vehicle for 48 h. Cells were washed twice in PBS (4°C) and lysed in RLT lysis buffer (Qiagen). Total RNA was isolated using the RNeasy Plus Mini Kit (Qiagen) according to the manufacturer’s instructions. Libraries were prepared using the Illumina® Stranded TruSeq® RNA sample preparation Kit.