Intrastriatally Infused Exogenous CDNF Is Endocytosed and Retrogradely Transported to Substantia Nigra

eNeuro. 2017 Feb 20;4(1):ENEURO.0128-16.2017. doi: 10.1523/ENEURO.0128-16.2017. eCollection Jan-Feb 2017.

Abstract

Cerebral dopamine neurotrophic factor (CDNF) protects the nigrostriatal dopaminergic (DA) neurons in rodent models of Parkinson's disease and restores DA circuitry when delivered after these neurons have begun to degenerate. These DA neurons have been suggested to transport striatal CDNF retrogradely to the substantia nigra (SN). However, in cultured cells the binding and internalization of extracellular CDNF has not been reported. The first aim of this study was to examine the cellular localization and pharmacokinetic properties of recombinant human CDNF (rhCDNF) protein after its infusion into rat brain parenchyma. Second, we aimed to study whether the transport of rhCDNF from the striatum to the SN results from its retrograde transport via DA neurons or from its anterograde transport via striatal GABAergic projection neurons. We show that after intrastriatal infusion, rhCDNF diffuses rapidly and broadly, and is cleared with a half-life of 5.5 h. Confocal microscopy analysis of brain sections at 2 and 6 h after infusion of rhCDNF revealed its widespread unspecific internalization by cortical and striatal neurons, exhibiting different patterns of subcellular rhCDNF distribution. Electron microscopy analysis showed that rhCDNF is present inside the endosomes and multivesicular bodies. In addition, we present data that after intrastriatal infusion the rhCDNF found in the SN is almost exclusively localized to the DA neurons, thus showing that it is retrogradely transported.

Keywords: CDNF; Parkinson’s disease.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adrenergic Agents / pharmacology
  • Animals
  • Corpus Striatum / drug effects
  • Corpus Striatum / metabolism*
  • Dopaminergic Neurons / metabolism
  • Dopaminergic Neurons / ultrastructure
  • Endocytosis / drug effects
  • Endocytosis / physiology*
  • Humans
  • Male
  • Mice
  • Microscopy, Immunoelectron
  • Nerve Growth Factors / administration & dosage*
  • Nerve Growth Factors / metabolism
  • Nerve Growth Factors / ultrastructure
  • Neural Pathways / drug effects
  • Neural Pathways / physiology
  • Oxidopamine / pharmacology
  • Phosphopyruvate Hydratase / metabolism
  • Protein Transport / drug effects
  • Protein Transport / genetics
  • Rats
  • Rats, Transgenic
  • Rats, Wistar
  • Substantia Nigra / drug effects
  • Substantia Nigra / metabolism*
  • Time Factors
  • Tyrosine 3-Monooxygenase / metabolism

Substances

  • Adrenergic Agents
  • CDNF protein, human
  • Nerve Growth Factors
  • Oxidopamine
  • Tyrosine 3-Monooxygenase
  • Phosphopyruvate Hydratase