Resolvin E1 promotes mucosal surface clearance of neutrophils: a new paradigm for inflammatory resolution

Abstract

Migration of neutrophils (PMN) across epithelia is a pathological hallmark of numerous muco- sal diseases. Whereas lesions at mucosal surfaces are generally self-limiting, endogenous mechanisms of res- olution are incompletely understood. Previous studies revealed that resolvins directly act on PMN to attenuate transendothelial migration, less is known about the influence of resolvins on PMN-epithelial interactions and whether they act on epithelia. We studied the dynamics of resolvin E1 (RvE1) actions on leukocyte transepithelial migration. PMN exposure to RvE1 or chemerin (peptide agonist of ChemR23) reduced trans- epithelial migration in a concentration-dependent man- ner. Conversely, activation of epithelial ChemR23 pro- moted apical clearance of PMN. A nonbiased screen of known PMN ligands expressed on epithelial cells in response to RvE1 revealed selective induction of CD55, an apically expressed antiadhesive molecule. CD55 promoter analysis demonstrated that both RvE1 and chemerin activate the CD55 promoter. Inhibition of CD55 by neutralizing antibody prevented RvE1-depen- dent augmentation of apical PMN clearance. Taken together these findings implicate a "two-hit" model of inflammatory resolution, whereby activation of the PMN RvE1 receptor attenuates transepithelial migra- tion and subsequent actions on the epithelium promote CD55-dependent clearance of PMN across the epithe- lial cell surface promoting active inflammatory resolu- tion.—Campbell, E. L., Louis, N. A., Tomassetti, S. E., Canny, G. O., Arita, M., Serhan, C. N., Colgan, S. P. Resolvin E1 promotes mucosal surface clearance of neutrophils: a new paradigm for inflammatory resolu- tion. FASEB J. 21, 3162-3170 (2007)