Optic nerve regeneration screen identifies multiple genes restricting adult neural repair

Cell Rep. 2021 Mar 2;34(9):108777. doi: 10.1016/j.celrep.2021.108777.


Adult mammalian central nervous system (CNS) trauma interrupts neural networks and, because axonal regeneration is minimal, neurological deficits persist. Repair via axonal growth is limited by extracellular inhibitors and cell-autonomous factors. Based on results from a screen in vitro, we evaluate nearly 400 genes through a large-scale in vivo regeneration screen. Suppression of 40 genes using viral-driven short hairpin RNAs (shRNAs) promotes retinal ganglion cell (RGC) axon regeneration after optic nerve crush (ONC), and most are validated by separate CRISPR-Cas9 editing experiments. Expression of these axon-regeneration-suppressing genes is not significantly altered by axotomy. Among regeneration-limiting genes, loss of the interleukin 22 (IL-22) cytokine allows an early, yet transient, inflammatory response in the retina after injury. Reduced IL-22 drives concurrent activation of signal transducer and activator of transcription 3 (Stat3) and dual leucine zipper kinase (DLK) pathways and upregulation of multiple neuron-intrinsic regeneration-associated genes (RAGs). Including IL-22, our screen identifies dozens of genes that limit CNS regeneration. Suppression of these genes in the context of axonal damage could support improved neural repair.

Keywords: AAV; CRISPR; IL-22; axon regeneration; gene editing; inflammation; optic nerve; retina; shRNA.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Axons / metabolism
  • Axons / pathology
  • CRISPR-Cas Systems
  • Dependovirus / genetics
  • Female
  • Gene Editing
  • Gene Expression Regulation
  • Genetic Association Studies
  • HEK293 Cells
  • Humans
  • Interleukins / genetics
  • Interleukins / metabolism
  • MAP Kinase Kinase Kinases / genetics
  • MAP Kinase Kinase Kinases / metabolism
  • Male
  • Mice, Inbred C57BL
  • Mice, Transgenic
  • Nerve Regeneration / genetics*
  • Neurogenesis / genetics*
  • Optic Nerve / metabolism*
  • Optic Nerve / pathology
  • Optic Nerve / physiopathology
  • Optic Nerve Injuries / genetics*
  • Optic Nerve Injuries / metabolism
  • Optic Nerve Injuries / pathology
  • Optic Nerve Injuries / physiopathology
  • Retinal Ganglion Cells / metabolism
  • Retinal Ganglion Cells / pathology
  • STAT3 Transcription Factor / genetics
  • STAT3 Transcription Factor / metabolism
  • Signal Transduction


  • Interleukins
  • STAT3 Transcription Factor
  • Stat3 protein, mouse
  • MAP Kinase Kinase Kinases
  • mitogen-activated protein kinase kinase kinase 12
  • interleukin-22