Frontiers in Neural Circuits (Dec 2013)

Regulation of thalamocortical axon branching by BDNF and synaptic vesicle cycling

  • Björn eGranseth,
  • Björn eGranseth,
  • Yuichi eFukushima,
  • Noriyuki eSugo,
  • Leon eLagnado,
  • Nobuhiko eYamamoto

DOI
https://doi.org/10.3389/fncir.2013.00202
Journal volume & issue
Vol. 7

Abstract

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During development, axons form branches in response to extracellular molecules. Little is known about the underlying molecular mechanisms. Here, we investigate how neurotrophin-induced axon branching is related to synaptic vesicle cycling for thalamocortical axons. The exogenous application of brain-derived neurotrophic factor (BDNF) markedly increased axon branching in thalamocortical co-cultures, while removal of endogenous BDNF reduced branching. Over-expression of a C-terminal fragment of AP180 that inhibits clathrin-mediated endocytosis affected the laminar distribution and the number of branch points. A dominant-negative synaptotagmin mutant that selectively targets synaptic vesicle cycling, strongly suppressed axon branching. Moreover, axons expressing the mutant synaptotagmin were resistant to the branch-promoting effect of BDNF. These results suggest that synaptic vesicle cycling might regulate BDNF induced branching during the development of the axonal arbor.

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