Critical examination of Ptbp1-mediated glia-to-neuron conversion in the mouse retina

Cell Rep. 2022 Jun 14;39(11):110960. doi: 10.1016/j.celrep.2022.110960.

Abstract

Reprogramming glial cells to convert them into neurons represents a potential therapeutic strategy that could repair damaged neural circuits and restore function. Recent studies show that downregulation of the RNA-binding protein PTBP1 leads to one-step conversion of Müller glia (MG) into retinal ganglion cells (RGCs) with a high efficiency. However, the original study did not perform fate-mapping experiments to confirm MG-to-RGC conversion after Ptbp1 downregulation. To address the fundamental question of whether Ptbp1 downregulation can convert MG into RGCs in the mouse retina, we perform fate-mapping experiments to lineage trace MG independent of the adeno-associated virus (AAV)-mediated labeling system. Here, we report that Ptbp1 downregulation by CRISPR-CasRx or small hairpin RNA is insufficient to convert MG to RGCs. The original conclusion of MG-to-RGC conversion is due to leaky labeling of endogenous RGCs. Our results emphasize the importance of using stringent fate mapping to determine glia-to-neuron conversion in cell reprogramming research.

Keywords: CP: Neuroscience; CP: Stem cell research; Müller glia; fate mapping; glia-to-neuron conversion; lineage tracing; reprogramming; retinal ganglion cells.

Publication types

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

MeSH terms

  • Animals
  • Cellular Reprogramming* / genetics
  • Dependovirus
  • Heterogeneous-Nuclear Ribonucleoproteins* / metabolism
  • Mice
  • Neuroglia* / metabolism
  • Polypyrimidine Tract-Binding Protein* / genetics
  • Polypyrimidine Tract-Binding Protein* / metabolism
  • RNA-Binding Proteins / metabolism
  • Retina
  • Retinal Ganglion Cells* / metabolism

Substances

  • Heterogeneous-Nuclear Ribonucleoproteins
  • Ptbp1 protein, mouse
  • RNA-Binding Proteins
  • Polypyrimidine Tract-Binding Protein