Diacylglycerol Lipase-β Is Required for TNF-α Response but Not CD8+ T Cell Priming Capacity of Dendritic Cells.

Diacylglycerol lipase-β (DAGLβ) hydrolyzes arachidonic acid (AA)-esterified diacylglycerols to produce 2-arachidonoylglycerol (2-AG) and downstream prostanoids that mediate inflammatory responses of macrophages. Here, we utilized DAGL-tailored activity-based protein profiling and genetic disruption models to discover that DAGLβ regulates inflammatory lipid and protein signaling pathways in primary dendritic cells (DCs). DCs serve as an important link between innate and adaptive immune pathways by relaying innate signals and antigen to drive T cell clonal expansion and prime antigen-specific immunity. We discovered that disruption of DAGLβ in DCs lowers cellular 2-AG and AA that is accompanied by reductions in lipopolysaccharide (LPS) stimulated tumor necrosis factor α secretion. Cell-based vaccination studies revealed that DC maturation ex vivo and immunogenicity in vivo was surprisingly unaffected by DAGLβ inactivation. Collectively, we identify DAGLβ pathways as a means for attenuating DC inflammatory signaling while sparing critical adaptive immune functions and further expand the utility of targeting lipid pathways for immunomodulation.