Triggering of NOD2 receptor converts inflammatory Ly6Chigh into Ly6Clow monocytes with patrolling properties.. Mus musculus

In the present study, we demonstrate that NOD2 receptor triggering by muramyl dipeptide converts blood inflammatory Ly6Chigh monocytes into patrolling Ly6Clow monocytes. Muramyl dipeptide administration to Nr4a1-/- mice, which lack Ly6Clow monocytes, and to Ly6Clow-depleted mice leads to the emergence of blood patrolling monocytes expressing phenotypic profile of typical Ly6Clow monocytes, including high expression of CX3CR1 and LFA1. Furthermore using intravital microscopy in live animal models of inflammatory diseases, we observed that converted Ly6Chigh monocytes are capable of patrolling the endothelium of blood vessels and their presence contributes to reduce the inflammatory response following muramyl dipeptide injection. Overall design: We study the effects of NOD2 triggering by muramyldipeptide on the monocytes subtypes in C57Bl/6, NR4A1-/- and NOD2-/- mice.