Distinct signature, origin and dynamics of macrophages in the peripheral and central nervous system (microarray)

We performed ontogenic, transcriptomic and spatial characterization of sciatic nerve Macs (snMacs). Using multiple fate-mapping systems, we show that snMacs do not derive from the early embryonic precursors colonizing the CNS, but originate primarily from late embryonic precursors and get replaced by bone marrow-derived Macs over time. Using single-cell profiling, we identified a tissue-specific core signature of snMacs and found two spatially-separated snMacs: Relmα + Mgl1 + snMacs in the epineurium and Relmα Mgl1 snMacs in the endoneurium. Globally, snMacs lack most core signature genes of microglia, with only the endoneurial subset expressing a restricted number of these genes. Single-cell transcriptomics revealed that in response to injury both snMacs respond differently and that the PNS, in contrast to the CNS, is permissive to prolonged engraftment of monocyte-derived Macs recruited upon injury.

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Ydens E, Amann L, Asselbergh B, Scott CL, Martens L, Sichien D, Mossad O, Blank T, De Prijck S, Low D, Masuda T, Saeys Y, Timmerman V, Stumm R, Ginhoux F, Prinz M, Janssens S, Guilliams M