Membrane-type Matrix Metalloproteinase-3 Regulates Neuronal Responsiveness to Myelin through Nogo-66 Receptor 1 Cleavage

Gino B Ferraro,Charlotte J Morrison,Christopher M Overall,Stephen M Strittmatter,Alyson E Fournier

doi:10.1074/jbc.m111.249169

Abstract

Nogo-66 receptor 1 (NgR1) is a glycosylphosphatidylinositol-anchored receptor for myelin-associated inhibitors that restricts plasticity and axonal regrowth in the CNS. NgR1 is cleaved from the cell surface of SH-SY5Y neuroblastoma cells in a metalloproteinase-dependent manner; however, the mechanism and physiological consequence of NgR1 shedding have not been explored. We now demonstrate that NgR1 is shed from multiple populations of primary neurons. Through a loss-of-function approach, we found that membrane-type matrix metalloproteinase-3 (MT3-MMP) regulates endogenous NgR1 shedding in primary neurons. Neuronal knockdown of MT3-MMP resulted in the accumulation of NgR1 at the cell surface and reduced the accumulation of the NgR1 cleavage fragment in medium conditioned by cortical neurons. Recombinant MT1-, MT2-, MT3-, and MT5-MMPs promoted NgR1 shedding from the surface of primary neurons, and this treatment rendered neurons resistant to myelin-associated inhibitors. Introduction of a cleavage-resistant form of NgR1 reconstitutes the neuronal response to these inhibitors, demonstrating that specific metalloproteinases attenuate neuronal responses to myelin in an NgR1-dependent manner.

Highlights

Nogo-66 receptor 1 (NgR1)2 was originally identified as a receptor for myelin-associated inhibitors (MAIs) (1)
We found that NgR1 was constitutively shed from SH-SY5Y cells, cortical neurons, dorsal root ganglion (DRG) neurons, cerebellar granule neurons, and brain lysates (Fig. 1C) and that shedding was blocked by the MMP inhibitors BB-94 and GM6001, but not by the inactive analog of GM6001
Our data identify MT3-MMP as a regulator of basal NgR1 shedding in cortical neurons

Summary

Introduction

Nogo-66 receptor 1 (NgR1)2 was originally identified as a receptor for myelin-associated inhibitors (MAIs) (1). Treatment of cortical neurons with recombinant MT1-, MT2-, and MT3-MMPs for 4 h resulted in accumulation of the NgR1 fragment in the medium and decreased full-length NgR1 at the cell surface (Fig. 2C).

Results

Conclusion