Transcriptional analysis of efferocytosis in mouse skin wounds

Defects in apoptotic cell clearance, or efferocytosis, can cause inflammatory diseases and prevent tissue repair due in part, to a key role of efferocytosis in inducing a pro-repair transcriptional program in phagocytic cells like macrophages. While the cellular machinery and metabolic pathways involved in efferocytosis have been characterized, the precise efferocytic response of macrophages is dependent on the identity and macromolecular cues of apoptotic cells, and the complex tissue microenvironment in which efferocytosis occurs. Here, we find that macrophages undergoing active efferocytosis in mid-stage mouse skin wounds in vivo display a pro-repair gene program, while efferocytosis of apoptotic skin fibroblasts in vitro induces an immature/inflammatory transcription response. These data provide a resource for understanding how the skin wound niche influences macrophage efferocytosis and will be useful for future investigations that define the role of efferocytosis during tissue repair In order to better understand efferocytosis function in the skin, we used both an in-vivo and in-vitro model of efferocytosis, followed by FACS isolation of Eff+ and Eff- cells. In-vivo samples were macrophages isolated from day 3 wounds on LysMCreER/mTmG mice. In-vitro samples were bone marrow derived macrophages treated with labled apoptotic fibroblasts and sorted by FACS.