Novel resolvin D2 receptor axis in infectious inflammation

N Chiang, X de la Rosa, S Libreros… - The Journal of …, 2017 - journals.aai.org
The Journal of Immunology, 2017journals.aai.org
Resolution of acute inflammation is an active process governed by specialized proresolving
mediators, including resolvin (Rv) D2, that activates a cell surface G protein–coupled
receptor, GPR18/DRV2. In this study, we investigated RvD2-DRV2–dependent resolution
mechanisms using DRV2-deficient mice (DRV2-knockout [KO]). In polymicrobial sepsis
initiated by cecal ligation and puncture, RvD2 (∼ 2.7 nmol/mouse) significantly increased
survival (> 50%) of wild-type mice and reduced hypothermia and bacterial titers compared …
Abstract
Resolution of acute inflammation is an active process governed by specialized proresolving mediators, including resolvin (Rv) D2, that activates a cell surface G protein–coupled receptor, GPR18/DRV2. In this study, we investigated RvD2-DRV2–dependent resolution mechanisms using DRV2-deficient mice (DRV2-knockout [KO]). In polymicrobial sepsis initiated by cecal ligation and puncture, RvD2 (∼ 2.7 nmol/mouse) significantly increased survival (> 50%) of wild-type mice and reduced hypothermia and bacterial titers compared with vehicle-treated cecal ligation and puncture mice that succumbed at 48 h. Protection by RvD2 was abolished in DRV2-KO mice. Mass spectrometry–based lipid mediator metabololipidomics demonstrated that DRV2-KO infectious exudates gave higher proinflammatory leukotriene B 4 and procoagulating thromboxane B 2, as well as lower specialized proresolving mediators, including RvD1 and RvD3, compared with wild-type. RvD2-DRV2–initiated intracellular signals were investigated using mass cytometry (cytometry by time-of-flight), which demonstrated that RvD2 enhanced phosphorylation of CREB, ERK1/2, and STAT3 in WT but not DRV2-KO macrophages. Monitored by real-time imaging, RvD2–DRV2 interaction significantly enhanced phagocytosis of live Escherichia coli, an action dependent on protein kinase A and STAT3 in macrophages. Taken together, we identified an RvD2/DRV2 axis that activates intracellular signaling pathways that increase phagocytosis-mediated bacterial clearance, survival, and organ protection. Moreover, these results provide evidence for RvD2-DRV2 and their downstream pathways in pathophysiology of infectious inflammation.
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