eLife Assessment
Following retinal injury, zebrafish Müller glia reenter the cell cycle and generate replacement cells; this potentially valuable study proposes that injury induces a cxcl18b+ transitional state in Müller cells, which then express nitric oxide, inhibiting Notch signaling and allowing Müller glial cells to reenter the cell cycle. However, the evidence supporting the claims is incomplete, and the authors have made interpretations and conclusions that are not supported by the data. Questions of the temporal expression and function of cxcl18b, as well as the source of potential inflammatory cues before cxcl18b expression, remain unanswered and technical limitations and data inconsistencies raise concerns. Using larval animals complicates the analysis since the retina is still forming, and distinguishing between injury-induced regeneration and ongoing development is complex. With more rigorous testing of the signaling pathways proposed and a clear demonstration of their interdependence, the link between nitric oxide signaling and Notch activity, particularly, would interest those investigating retinal regeneration.