Transcription factor REST/NRSF regulates optic nerve regeneration and RGC survival

Abstract

Purpose : Like other pathways in the mature central nervous system, the optic nerve cannot regenerate if injured, resulting in lifelong losses in vision. Discoveries over the past few decades have demonstrated the importance of growth factors derived from inflammatory cells, cell-intrinsic suppressors of key signal transduction pathways, transcription factors (TFs), intercellular communication networks, and cell-extrinsic suppressors of axon growth as all playing an important role in regulating optic nerve regeneration and retinal ganglion cell (RGC) survival. Despite these advances, however, little is known about genes that act as upstream drivers of regenerative failure.

Methods : We used system-genomics approaches to characterize regulatory relationships of regeneration-associated TFs and to identify transcriptional regulators of the regenerative program. Cell culture and in vivo experiments in mice enabled us to validate the role of leading candidate TFs.

Results : We identified RE1-Silencing Transcription Factor (REST; Neuron-Restrictive Silencer Factor, NRSF) as a potential upstream inhibitor of axon regeneration. Down-regulation of REST using adeno-associated virus-mediated expression of a dominant-negative REST mutant (AAV2-d/nREST) increased axon outgrowth in RGC cultures and greatly enhanced outgrowth induced by the neutrophil-derived growth factor oncomodulin (Ocm) combined with cAMP (a co-factor for Ocm). REST knockdown up-regulated other regeneration-related transcription factors (e.g., Sox11, ATF3) and downstream growth-associated genes (e.g., GAP-43). In vivo, conditional knockout of REST in RGCs or expression of AAV2-d/nREST led to considerable axon regeneration and increased RGC survival after optic nerve injury.

Conclusions : REST is a critical upstream regulator of optic nerve regeneration and RGC survival.

This is a 2020 ARVO Annual Meeting abstract.

 

Inactivation of REST leads to optic nerve regeneration. Wildtype mice received AAV2-d/nREST virus (d/nREST) or AAV2-GFP (Control) intraocularly 2 weeks before the optic nerve crush and combined with Ocm+cAMP (Ocm+cAMP) immediately after the nerve injury. Regenerating axons are labeled by CTB (green fluorescence). Asterisk: nerve injury site. Scale bar: 200 µm