A role for Nogo receptor in macrophage clearance from injured peripheral nerve

EJ Fry, C Ho, S David - Neuron, 2007 - cell.com
EJ Fry, C Ho, S David
Neuron, 2007cell.com
We report a role for Nogo receptors (NgRs) in macrophage efflux from sites of inflammation
in peripheral nerve. Increasing numbers of macrophages in crushed rat sciatic nerves
express NgR1 and NgR2 on the cell surface in the first week after injury. These
macrophages show reduced binding to myelin and MAG in vitro, which is reversed by NgR
siRNA knockdown and by inhibiting Rho-associated kinase. Fourteen days after sciatic
nerve crush, regenerating nerves with newly synthesized myelin have fewer macrophages …
Summary
We report a role for Nogo receptors (NgRs) in macrophage efflux from sites of inflammation in peripheral nerve. Increasing numbers of macrophages in crushed rat sciatic nerves express NgR1 and NgR2 on the cell surface in the first week after injury. These macrophages show reduced binding to myelin and MAG in vitro, which is reversed by NgR siRNA knockdown and by inhibiting Rho-associated kinase. Fourteen days after sciatic nerve crush, regenerating nerves with newly synthesized myelin have fewer macrophages than cut/ligated nerves that lack axons and myelin. Almost all macrophages in the cut/ligated nerves lie within the Schwann cell basal lamina, while in the crushed regenerating nerves the majority migrate out. Furthermore, crush-injured nerves of NgR1- and MAG-deficient mice and Y-27632-treated rats show impaired macrophage efflux from Schwann cell basal lamina containing myelinated axons. These data have implications for the resolution of inflammation in peripheral nerve and CNS pathologies.
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