Abstract
Resolution of inflammation is now recognized as a biosynthetically active process involving pro-resolving mediators. Here, we show in zymosan-initiated peritoneal inflammation that the vagus nerve regulates local expression of netrin-1, an axonal guidance molecule that activates resolution, and that vagotomy reduced local pro-resolving mediators, thereby delaying resolution. In netrin-1(+/-) mice, resolvin D1 (RvD1) was less effective in reducing neutrophil influx promoting resolution of peritonitis compared with Ntn1(+/+). Netrin-1 shortened the resolution interval, decreasing exudate neutrophils, reducing proinflammatory mediators, and stimulating the production of resolvins, protectins, and lipoxins. Human monocytes incubated with netrin-1 produced proresolving mediators, including resolvins and lipoxins. Netrin-1 and RvD1 displayed bidirectional activation in that they stimulated each other's expression and enhanced efferocytosis. These results indicate that the vagus nerve regulates both netrin-1 and pro-resolving lipid mediators, which act in a bidirectional fashion to stimulate resolution, and provide evidence for a novel mechanism for local neuronal control of resolution.