Down-regulation of dopamine transporter by iron chelation in vitro is mediated by altered trafficking, not synthesis

Jason A. Wiesinger, James P. Buwen, Christopher J. Cifelli, Erica L. Unger, Byron Jones, John L. Beard

Research output: Contribution to journalArticle

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Abstract

Neurological development and functioning of dopamine (DA) neurotransmission is adversely affected by iron deficiency in early life. Iron-deficient rats demonstrate significant elevations in extracellular DA and a reduction in dopamine transporter (DAT) densities in the caudate putamen and nucleus accumbens. To explore possible mechanisms by which cellular iron concentrations control DAT functioning, endogenous DAT-expressing PC12 cells were used to determine the effect of iron chelation on DAT protein and mRNA expression patterns. In addition, we used human DAT (hDAT)-transfected Neuro2a (N2A) cells to examine DAT degradation and trafficking patterns. A 50 μm treatment for 24 h with the iron chelator, desferrioxamine (DFO), significantly decreased dopamine uptake in a dose-dependent manner, with no apparent change in K m, in both PC12 and N2A cells. Reduced DA uptake was accompanied by concentration- and time-dependent reductions in total DAT protein levels in both cell lines. Exposure to increasing concentrations of DFO did not significantly alter DAT mRNA in either PC12 or N2A cells. However, DAT degradation rates increased three-fivefold in both cell types exposed to 50 μm DFO for 24 h. Biotinylation studies in N2A cells indicate a more dramatic loss of DAT in the membrane fraction, while OptiPrep fractionation experiments revealed an increase in lysosomal DAT with iron chelation. Inhibition of protein kinase C activation with staurosporin prevented the effect of iron chelation on DAT function, suggesting that in vitro iron chelation affects DAT primarily through the effects on trafficking rather than on synthesis.

Original languageEnglish (US)
Pages (from-to)167-179
Number of pages13
JournalJournal of Neurochemistry
Volume100
Issue number1
DOIs
StatePublished - Jan 1 2007
Externally publishedYes

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Dopamine Plasma Membrane Transport Proteins
Chelation
Down-Regulation
Iron
Deferoxamine
Dopamine
PC12 Cells
In Vitro Techniques
Biotinylation
Degradation
Messenger RNA
Caudate Nucleus
Putamen
Nucleus Accumbens
Fractionation
Chelating Agents
Synaptic Transmission
Protein Kinase C
Rats

All Science Journal Classification (ASJC) codes

  • Biochemistry
  • Cellular and Molecular Neuroscience

Cite this

Down-regulation of dopamine transporter by iron chelation in vitro is mediated by altered trafficking, not synthesis. / Wiesinger, Jason A.; Buwen, James P.; Cifelli, Christopher J.; Unger, Erica L.; Jones, Byron; Beard, John L.

In: Journal of Neurochemistry, Vol. 100, No. 1, 01.01.2007, p. 167-179.

Research output: Contribution to journalArticle

Wiesinger, Jason A. ; Buwen, James P. ; Cifelli, Christopher J. ; Unger, Erica L. ; Jones, Byron ; Beard, John L. / Down-regulation of dopamine transporter by iron chelation in vitro is mediated by altered trafficking, not synthesis. In: Journal of Neurochemistry. 2007 ; Vol. 100, No. 1. pp. 167-179.
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