Live, die, or regenerate? New insights from multi-omic analyses

Abstract

In this issue of Neuron, three studies establish new strategies to uncover mediators of retinal neuroprotection and optic nerve regeneration. Tian et al. (2022) carry out a multi-omics screen and identify transcriptional regulators of axon injury signaling leading to cell death; Jacobi et al. (2022) and Li et al. (2022) combine retrograde tracing and single-cell RNA-seq (scRNA-seq) to uncover molecular targets for axon regeneration.

Figure 1.. Multi-omics approaches to uncover new transcriptional pathways for neuroprotection and molecular targets for effective axon regeneration.

(A) Tian et al. performed an AAV-mediated in vivo CRISPR loss-of-function screen against all known mammalian TFs following ONC. RGC counts reflecting neuroprotection and RGC axon regeneration were assessed following the deletion of each TF. By integrating their CRISPR screening results with ATAC-Seq and RNA-Seq of injured RGCs following ONC, the authors uncovered parallel core transcriptional machinery to boost neuroprotection with synergistic effects in ONC and glaucomatous conditions. (B & C) Jacobi et al. and Li et al. profiled RGCs primed for regeneration with scRNA-Seq following ONC and used retrograde labeling methods to distinguish regenerating from surviving but non-regenerating RGCs. The two studies used different surgical methods, as shown, to deliver a small-molecular weight fluorescent dye for retrograde labeling. (B) Jacobi et al. uncovered RGC taxonomy changes under three different regenerative interventions; differentiated GO patterns among dying, surviving, and regenerating RGCs; and showed that several molecules in neuropeptide signaling are critical for optic nerve regeneration. (C) Li et al. compared regenerating RGCs to surviving but non-regenerating RGCs followed by PTEN KO and identified differentially expressed genes between the two RGC groups. They then tested the regeneration-associated genes using an AAV-overexpression screen. They uncovered a role for the tPA/Anxa2 pathway in promoting axon regeneration and protecting RGC loss under glaucomatous conditions.