PUBLICATION

Serotonin neuromodulation directs optic nerve regeneration

Authors
Saied-Santiago, K., Baxter, M., Mathiaparanam, J., Granato, M.
ID
ZDB-PUB-250617-11
Date
2025
Source
Development (Cambridge, England)   152: dev204334 (Journal)
Registered Authors
Granato, Michael
Keywords
Optic nerve, 5HT, Axon regeneration, Serotonin, Zebrafish
MeSH Terms
  • Animals
  • Axons/metabolism
  • Axons/physiology
  • Nerve Regeneration*/drug effects
  • Nerve Regeneration*/physiology
  • Optic Nerve*/drug effects
  • Optic Nerve*/physiology
  • Optic Nerve Injuries
  • Receptors, Serotonin, 5-HT1/genetics
  • Receptors, Serotonin, 5-HT1/metabolism
  • Retinal Ganglion Cells/metabolism
  • Serotonin*/metabolism
  • Signal Transduction/drug effects
  • Zebrafish/physiology
  • Zebrafish Proteins/genetics
  • Zebrafish Proteins/metabolism
PubMed
40521655 Full text @ Development
Abstract
Optic nerve (ON) regeneration in mammalian systems is limited by an overshadowing dominance of inhibitory factors. This has severely hampered the identification of pro-regenerative pathways. Here, we take advantage of the regenerative capacity of larval zebrafish to identify pathways that promote ON regeneration. From a small molecule screen, we identified modulators of serotonin (5-HT) signaling that inhibit ON regeneration. We find several serotonin type-1 receptor genes are expressed in RGC neurons during regeneration and that inhibiting 5-HT1 receptors or components of the 5-HT pathway selectively impedes ON regeneration. We show that 5-HT1 receptor signaling is dispensable during ON development yet is critical for regenerating axons to emerge from the injury site. Blocking 5-HT receptors once ON axons have crossed the chiasm does not inhibit regeneration, suggesting a selective role for 5-HT receptor signaling early during ON regeneration. Finally, we show that agonist-mediated activation of 5-HT1 receptors leads to enhanced and ectopic axonal regrowth. Combined, our results provide evidence for mechanisms through which serotonin-dependent neuromodulation directs ON regeneration in vivo.
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