Teneurin trans-axonal signaling prunes topographically missorted axons

• Published in: Cell reports (Cambridge) Vol. 42; no. 3; p. 112192
• Main Authors: Spead, Olivia, Moreland, Trevor, Weaver, Cory J., Costa, Irene Dalla, Hegarty, Brianna, Kramer, Kenneth L., Poulain, Fabienne E.
• Format: Journal Article
• Language: English
• Published: United States Elsevier Inc 28.03.2023; Elsevier
• Subjects: axon signaling; axon-axon interactions; Axons - metabolism; CP: Neuroscience; degeneration; Glypicans - metabolism; heparan sulfate; pre-target axon sorting; refinement; Retina - physiology; Retinal Ganglion Cells - metabolism; Visual Pathways - physiology; zebrafish; heparan sulfate; CP: Neuroscience; pre-target axon sorting; axon-axon interactions; axon signaling; refinement; zebrafish; degeneration
• ISSN: 2211-1247; 2211-1247
• DOI: 10.1016/j.celrep.2023.112192

Building precise neural circuits necessitates the elimination of axonal projections that have inaccurately formed during development. Although axonal pruning is a selective process, how it is initiated and controlled in vivo remains unclear. Here, we show that trans-axonal signaling mediated by the cell surface molecules Glypican-3, Teneurin-3, and Latrophilin-3 prunes misrouted retinal axons in the visual system. Retinotopic neuron transplantations revealed that pioneer ventral axons that elongate first along the optic tract instruct the pruning of dorsal axons that missort in that region. Glypican-3 and Teneurin-3 are both selectively expressed by ventral retinal ganglion cells and cooperate for correcting missorted dorsal axons. The adhesion G-protein-coupled receptor Latrophilin-3 signals along dorsal axons to initiate the elimination of topographic sorting errors. Altogether, our findings show an essential function for Glypican-3, Teneurin-3, and Latrophilin-3 in topographic tract organization and demonstrate that axonal pruning can be initiated by signaling among axons themselves. [Display omitted] •Pioneer axons instruct the pruning of follower axons that topographically missort•Glypican-3 and Teneurin-3 cooperate along pioneer axons to initiate pruning•The receptor Latrophilin-3.1 signals cell autonomously for pruning•Neuropilin-1 signaling is dispensable for pre-target retinal axon sorting Building accurate neural circuits requires eliminating axonal projections that have inaccurately formed during development. Spead et al. report that trans-axonal signaling mediated by Glypican-3, Teneurin-3, and Latrophilin-3.1 eliminates the axons that topographically misroute in the visual system. Thus, axons can instruct the pruning of other axons for precise circuit wiring.