Regulation of glutamate transporter trafficking by Nedd4-2 in a Parkinson's disease model

Cell Death Dis. 2017 Feb 2;8(2):e2574. doi: 10.1038/cddis.2016.454.

Abstract

Glutamate transporters play a key role in glutamate clearance and protect the central nervous system from glutamate excitotoxicity. Dysfunctional glutamate transporters contribute to the pathogenesis of Parkinson's disease (PD); however, the mechanisms that underlie the regulation of glutamate transporters in PD are still not well characterized. Here we report that Nedd4-2 mediates the ubiquitination of glutamate transporters in 1-methyl-4- phenylpyridinium (MPP+)-treated astrocytes and in the midbrain of 1-methyl-4-phenyl-1,2,3,6- tetrahydropyridine (MPTP)-constructed PD model mice. Nedd4-2-mediated ubiquitination induces abnormal glutamate transporter trafficking between the membrane and cytoplasm and consequently decreases the expression and function of glutamate transporters in the membrane. Conversely, Nedd4-2 knockdown decreases glutamate transporter ubiquitination, promotes glutamate uptake and increases glutamate transporter expression in vitro and in vivo. We report for the first time that Nedd4-2 knockdown ameliorates movement disorders in PD mice and increases tyrosine hydroxylase expression in the midbrain and striatum of PD mice; Nedd4-2 knockdown also attenuates astrogliosis and reactive microgliosis in the MPTP model that may be associated with glutamate excitotoxicity. Furthermore, the SGK/PKC pathway is regulated downstream of Nedd4-2 in MPTP-treated mice. These findings indicate that Nedd4-2 may serve as a potential therapeutic target for the treatment of PD.

MeSH terms

  • 1-Methyl-4-phenyl-1,2,3,6-tetrahydropyridine / pharmacology
  • 1-Methyl-4-phenylpyridinium / pharmacology
  • Amino Acid Transport System X-AG / metabolism*
  • Animals
  • Astrocytes / drug effects
  • Astrocytes / metabolism
  • Cells, Cultured
  • Corpus Striatum / drug effects
  • Corpus Striatum / metabolism
  • Cytoplasm / drug effects
  • Cytoplasm / metabolism
  • Disease Models, Animal
  • Endosomal Sorting Complexes Required for Transport / metabolism*
  • Glutamic Acid / metabolism
  • Male
  • Membranes / drug effects
  • Membranes / metabolism
  • Mesencephalon / drug effects
  • Mesencephalon / metabolism
  • Mice
  • Mice, Inbred C57BL
  • Nedd4 Ubiquitin Protein Ligases
  • Parkinson Disease / metabolism*
  • Protein Kinase C / metabolism
  • Protein Serine-Threonine Kinases / metabolism
  • Protein Transport / drug effects
  • Tyrosine 3-Monooxygenase / metabolism
  • Ubiquitin-Protein Ligases / metabolism*
  • Ubiquitination / drug effects

Substances

  • Amino Acid Transport System X-AG
  • Endosomal Sorting Complexes Required for Transport
  • Glutamic Acid
  • 1-Methyl-4-phenyl-1,2,3,6-tetrahydropyridine
  • Tyrosine 3-Monooxygenase
  • Nedd4 Ubiquitin Protein Ligases
  • Nedd4l protein, mouse
  • Ubiquitin-Protein Ligases
  • Protein Serine-Threonine Kinases
  • Protein Kinase C
  • 1-Methyl-4-phenylpyridinium