rab-27 acts in an intestinal pathway to inhibit axon regeneration in C. elegans

PLoS Genet. 2021 Nov 24;17(11):e1009877. doi: 10.1371/journal.pgen.1009877. eCollection 2021 Nov.

Abstract

Injured axons must regenerate to restore nervous system function, and regeneration is regulated in part by external factors from non-neuronal tissues. Many of these extrinsic factors act in the immediate cellular environment of the axon to promote or restrict regeneration, but the existence of long-distance signals regulating axon regeneration has not been clear. Here we show that the Rab GTPase rab-27 inhibits regeneration of GABAergic motor neurons in C. elegans through activity in the intestine. Re-expression of RAB-27, but not the closely related RAB-3, in the intestine of rab-27 mutant animals is sufficient to rescue normal regeneration. Several additional components of an intestinal neuropeptide secretion pathway also inhibit axon regeneration, including NPDC1/cab-1, SNAP25/aex-4, KPC3/aex-5, and the neuropeptide NLP-40, and re-expression of these genes in the intestine of mutant animals is sufficient to restore normal regeneration success. Additionally, NPDC1/cab-1 and SNAP25/aex-4 genetically interact with rab-27 in the context of axon regeneration inhibition. Together these data indicate that RAB-27-dependent neuropeptide secretion from the intestine inhibits axon regeneration, and point to distal tissues as potent extrinsic regulators of regeneration.

Publication types

  • Research Support, N.I.H., Extramural

MeSH terms

  • Animals
  • Axons / physiology*
  • Caenorhabditis elegans / physiology*
  • Caenorhabditis elegans Proteins / genetics
  • Caenorhabditis elegans Proteins / metabolism*
  • GABAergic Neurons / physiology*
  • Intestines / metabolism*
  • Regeneration*
  • Signal Transduction
  • Synaptic Vesicles / metabolism
  • rab GTP-Binding Proteins / genetics
  • rab GTP-Binding Proteins / metabolism*
  • rab27 GTP-Binding Proteins / genetics
  • rab27 GTP-Binding Proteins / metabolism*

Substances

  • Caenorhabditis elegans Proteins
  • rab27 GTP-Binding Proteins
  • aex-6 protein, C elegans
  • rab GTP-Binding Proteins