Molecular Neurobiology

, Volume 24, Issue 1, pp 1–28

Anterograde axonal transport, transcytosis, and recycling of neurotrophic factors

The concept of trophic currencies in neural networks
  • Christopher S. von Bartheld
  • XiaoXia Wang
  • Rafal Butowt
Article

DOI: 10.1385/MN:24:1-3:001

Cite this article as:
von Bartheld, C.S., Wang, X. & Butowt, R. Mol Neurobiol (2001) 24: 1. doi:10.1385/MN:24:1-3:001

Abstract

Traditional views of neurotrophic factor biology held that trophic factors are released from target cells, retrogradely transported along their axons, and rapidly degraded upon arrival in cell bodies. Increasing evidence indicates that several trophic factors such as brain-derived neurotrophic factor (BDNF), fibroblast growth factor (FGF-2), glial cell-line derived neurotrophic factor (GDNF), insulin-like growth factor (IGF-I), and neurotrophin-3 (NT-3), can move anterogradely along axons. They can escape the degradative pathway upon internalization and are recycled for future uses. Internalized ligands can move through intermediary cells by transcytosis, presumably by endocytosis via endosomes to the Golgi system, by trafficking of the factor to dendrites or by sorting into anterograde axonal transport with subsequent release from axon terminals and uptake by second- or third-order target neurons. Such data suggest the existence of multiple “trophic currencies,” which may be used over several steps in neural networks to enable nurturing relationships between connected neurons or glial cells, not unlike currency exchanges between trading partners in the world economy. Functions of multistep transfer of trophic material through neural networks may include regulation of neuronal survival, differentiation of phenotypes and dendritic morphology, synapse plasticity, as well as excitatory neurotransmission. The molecular mechanisms of sorting, trafficking, and release of trophic factors from distinct neuronal compartments are important for an understanding of neurotrophism, but they present challenging tasks owing to the low levels of the endogeneous factors.

Index Entries

Neurotrophic factoranterograde axonal transporttranscytosisneurotrophininternalizationendocytosisreleasedegradationNGFBDNFNT-3GDNFIGF-I

Copyright information

© Humana Press Inc 2001

Authors and Affiliations

  • Christopher S. von Bartheld
    • 1
  • XiaoXia Wang
    • 1
  • Rafal Butowt
    • 1
    • 2
  1. 1.Department of Physiology and Cell BiologyUniversity of Nevada School of MedicineReno
  2. 2.Department of NeurophysiologyNencki Institute of Experimental BiologyWarsawPoland