Language

English

Publication Date

12-13-2022

Journal

Immunity

DOI

10.1016/j.immuni.2022.10.018

PMID

36379210

PMCID

PMC9772037

PubMedCentral® Posted Date

12-13-2023

PubMedCentral® Full Text Version

Post-print

Abstract

Microglia utilize their phagocytic activity to prune redundant synapses and refine neural circuits during precise developmental periods. However, the neuronal signals that control this phagocytic clockwork remain largely undefined. Here, we show that neuronal signal-regulatory protein alpha (SIRPα) is a permissive cue for microglial phagocytosis in the developing murine retina. Removal of neuronal, but not microglial, SIRPα reduced microglial phagocytosis, increased synpase numbers, and impaired circuit function. Conversely, prolonging neuronal SIRPα expression extended developmental microglial phagocytosis. These outcomes depended on the interaction of presynaptic SIRPα with postsynaptic CD47. Global CD47 deficiency modestly increased microglial phagocytosis, while CD47 overexpression reduced it. This effect was rescued by coexpression of neuronal SIRPα or codeletion of neuronal SIRPα and CD47. These data indicate that neuronal SIRPα regulates microglial phagocytosis by limiting microglial SIRPα access to neuronal CD47. This discovery may aid our understanding of synapse loss in neurological diseases.

Keywords

Mice, Animals, CD47 Antigen, Receptors, Immunologic, Macrophages, Phagocytosis, Retina, Antigens, Differentiation, microglia, SIRPα, synapse refinement, retina

Published Open-Access

yes

nihms-1850845-f0001.jpg (260 kB)
Graphical Abstract

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