CCRL2 expression by specialized lung capillary endothelial cells controls NK cells homing in lung cancer

Patterns of chemotactic receptors regulate the homing of leukocytes to tissues. Here we report that the CCRL2/chemerin/CMKLR1 axis represent a selective pathway for the homing of NK cells to the lung. CCRL2 is a non-signaling seven-transmembrane domain receptor able to control lung tumor growth. Total or endothelial cell targeted CCRL2 deletion or the deletion of its ligand chemerin were found to promote tumor progression in a KrasG12D/+;p53LoxP lung cancer model. This phenotype was dependent on the reduced recruitment of CD27-CD11b+ mature NK cells. Mining scRNA-seq databases identified CCRL2 expression as the hallmark of general alveolar lung capillary endothelial cells (gCaps). CCRL2 expression is epigenetically regulated in lung endothelium. In vivo administration of low doses of the demethylating agent 5-Aza induced CCRL2 upregulation, increased recruitment of NK cells and lung protection in a tumor model. These results identify CCRL2 as a NK cell lung homing molecule that might be exploited to promote NK cell-mediated lung immune surveillance. To investigate the role of Ccrl2 in lung NK cells recruitment, scRNA sequencing was performed in total ILCs (CD45 + NKp46 + CD127 + cells) purified from Kras G12D/+ /p53 LoxP TK WT and Ccrl2 deficient mice.