Deletion of SIRPα (signal regulatory protein-α) promotes phagocytic clearance of myelin debris in Wallerian degeneration axon regeneration and recovery from nerve injury

摘要

Macrophages present in Wallerian degeneration express SIRPα in wild-type mice. – Cryostat sections in which CD47 ( , , ) and SIRPα ( , , ) were visualized by immunofluorescence microscopy using anti-CD47 and anti-SIRPα mAbs. Sections were taken from intact sciatic nerve ( , ), sciatic nerve undergoing in vivo Wallerian degeneration for 5 days ( , ), and cultured sciatic nerve explant undergoing in vitro Wallerian degeneration for 5 days ( , ). All three tissues displayed immunoreactivity to CD47 whereas only sciatic nerve undergoing in vivo Wallerian degeneration displayed immunoreactivity to SIRPα. Bar in : 100 μm, for through . – Three macrophages ( – ), ( – ), and ( – ) from 7 days in vivo Wallerian degenerating nerve segments were visualized by immunofluorescence microscopy using anti-SIRPα ( , , ; red) and anti-αM/CD11b subunit of CR3 ( , , ; green) Abs. SIRPα and CR3 combined ( , , ). Hoechst staining visualized nuclei (blue). The three cells displayed immunoreactivity to both SIRPα and CR3. Bar in : 5 μm, for through .