DEL-1 promotes macrophage efferocytosis and clearance of inflammation

I Kourtzelis, X Li, I Mitroulis, D Grosser, T Kajikawa… - Nature …, 2019 - nature.com
I Kourtzelis, X Li, I Mitroulis, D Grosser, T Kajikawa, B Wang, M Grzybek, J Von Renesse…
Nature immunology, 2019nature.com
Resolution of inflammation is essential for tissue homeostasis and represents a promising
approach to inflammatory disorders. Here we found that developmental endothelial locus-1
(DEL-1), a secreted protein that inhibits leukocyte–endothelial adhesion and inflammation
initiation, also functions as a non-redundant downstream effector in inflammation clearance.
In human and mouse periodontitis, waning of inflammation was correlated with DEL-1
upregulation, whereas resolution of experimental periodontitis failed in DEL-1 deficiency …
Abstract
Resolution of inflammation is essential for tissue homeostasis and represents a promising approach to inflammatory disorders. Here we found that developmental endothelial locus-1 (DEL-1), a secreted protein that inhibits leukocyte–endothelial adhesion and inflammation initiation, also functions as a non-redundant downstream effector in inflammation clearance. In human and mouse periodontitis, waning of inflammation was correlated with DEL-1 upregulation, whereas resolution of experimental periodontitis failed in DEL-1 deficiency. This concept was mechanistically substantiated in acute monosodium-urate-crystal-induced inflammation, where the pro-resolution function of DEL-1 was attributed to effective apoptotic neutrophil clearance (efferocytosis). DEL-1-mediated efferocytosis induced liver X receptor–dependent macrophage reprogramming to a pro-resolving phenotype and was required for optimal production of at least certain specific pro-resolving mediators. Experiments in transgenic mice with cell-specific overexpression of DEL-1 linked its anti-leukocyte-recruitment action to endothelial cell–derived DEL-1 and its efferocytic/pro-resolving action to macrophage-derived DEL-1. Thus, the compartmentalized expression of DEL-1 facilitates distinct homeostatic functions in an appropriate context that can be harnessed therapeutically.
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