Enhanced Functional Genomic Screening Identifies Novel Mediators of Dual Leucine Zipper Kinase-Dependent Injury Signaling in Neurons

Neuron. 2017 Jun 21;94(6):1142-1154.e6. doi: 10.1016/j.neuron.2017.06.008.

Abstract

Dual leucine zipper kinase (DLK) has been implicated in cell death signaling secondary to axonal damage in retinal ganglion cells (RGCs) and other neurons. To better understand the pathway through which DLK acts, we developed enhanced functional genomic screens in primary RGCs, including use of arrayed, whole-genome, small interfering RNA libraries. Explaining why DLK inhibition is only partially protective, we identify leucine zipper kinase (LZK) as cooperating with DLK to activate downstream signaling and cell death in RGCs, including in a mouse model of optic nerve injury, and show that the same pathway is active in human stem cell-derived RGCs. Moreover, we identify four transcription factors, JUN, activating transcription factor 2 (ATF2), myocyte-specific enhancer factor 2A (MEF2A), and SRY-Box 11 (SOX11), as being the major downstream mediators through which DLK/LZK activation leads to RGC cell death. Increased understanding of the DLK pathway has implications for understanding and treating neurodegenerative diseases.

Keywords: DLK (dual leucine zipper kinase); LZK (leucine zipper kinase); Neuroprotection; RGC (retinal ganglion cell); RNAi screen; cell death signaling; glaucoma.

MeSH terms

  • Animals
  • Cell Death
  • Cell Survival / drug effects
  • Cell Survival / genetics*
  • Disease Models, Animal
  • Flow Cytometry
  • Human Embryonic Stem Cells / cytology
  • Humans
  • Immunoprecipitation
  • MAP Kinase Kinase Kinases / genetics*
  • MAP Kinase Kinase Kinases / metabolism*
  • Mice
  • Mice, Knockout
  • Neurites
  • Neurons
  • Optic Nerve Injuries / genetics*
  • Optic Nerve Injuries / pathology
  • Piperazines / pharmacology
  • Protein Kinase Inhibitors / pharmacology
  • Real-Time Polymerase Chain Reaction
  • Retina / cytology
  • Retinal Ganglion Cells / drug effects
  • Retinal Ganglion Cells / metabolism*
  • Retinal Ganglion Cells / pathology

Substances

  • Piperazines
  • Protein Kinase Inhibitors
  • VX680
  • Lzk protein, mouse
  • MAP Kinase Kinase Kinases
  • mitogen-activated protein kinase kinase kinase 12