Impact of alcohol abuse on protein expression of midkine and excitatory amino acid transporter 1 in the human prefrontal cortex

Flatscher-Bader, Traute and Wilce, Peter A. (2008) Impact of alcohol abuse on protein expression of midkine and excitatory amino acid transporter 1 in the human prefrontal cortex. Alcoholism: Clinical and Experimental Research, 32 10: 1849-1858. doi:10.1111/j.1530-0277.2008.00754.x


Author Flatscher-Bader, Traute
Wilce, Peter A.
Title Impact of alcohol abuse on protein expression of midkine and excitatory amino acid transporter 1 in the human prefrontal cortex
Journal name Alcoholism: Clinical and Experimental Research   Check publisher's open access policy
ISSN 0145-6008
1530-0277
Publication date 2008-10-01
Sub-type Article (original research)
DOI 10.1111/j.1530-0277.2008.00754.x
Open Access Status Not yet assessed
Volume 32
Issue 10
Start page 1849
End page 1858
Total pages 10
Place of publication Oxford, England
Publisher Wiley-Blackwell Publishing
Language eng
Subject C1
110199 Medical Biochemistry and Metabolomics not elsewhere classified
970106 Expanding Knowledge in the Biological Sciences
Formatted abstract
Background:
Alcoholism is associated with shrinkage of brain tissue and reduction in the number of neurons and dendritic arbors particularly in the prefrontal cortex. These changes correlate with the cognitive defects common in alcoholics. A recent study investigated the mRNA expression of selected genes in the prefrontal cortex and found that the levels of mRNA encoding the neurotrophic factor, midkine (MDK), and the excitatory amino acid transporter 1 (EAAT1) were significantly higher in alcoholics compared with nonalcoholic controls. This study aimed to investigate, whether the transcriptional changes observed result in alterations to protein expression. Additionally, the study aimed to expand our understanding of MDK and EAAT1 action by localizing their expression within morphologically and functionally distinct layers of this brain region.

Methods:
Quantitative changes in protein levels of MDK and EAAT1 were investigated in alcoholic and control cases using Western blots. Immunohistochemistry was utilized to localize proteins expression in formalin-fixed sagittal sections of the prefrontal cortex.

Results:
A marked increase was revealed in protein expression of both genes in the prefrontal cortex of chronic alcoholics. MDK-like immunofluorescence in alcoholic and control cases was present in nuclei throughout the prefrontal cortex and was particularly apparent in cell bodies of astrocytes in cortical layer II. Immunolabeling of the EAAT1 was densest in cortical layer II in control cases and induced in deeper layers in alcoholic cases.

Conclusion:
Midkine promotes neuronal outgrowth and survival. The up-regulation of MDK protein expression may indicate the induction of reparative processes. The amino acid transporter is vital for the removal of glutamate from the synaptic cleft. At alcohol withdrawal, extracellular glutamate is thought to reach excitotoxic concentrations. Up-regulation of EAAT1 throughout the cortical layers may indicate an attempt to combat elevated glutamate concentrations. The predominant expression of the two proteins in layer II of the cortex implies a region-specific role of astrocytes.
Keyword drug abuse
alcohol abuse
mesocorticolimbic system
neuroprotection
glutamate
Q-Index Code C1
Q-Index Status Confirmed Code

Document type: Journal Article
Sub-type: Article (original research)
Collections: 2009 Higher Education Research Data Collection
School of Chemistry and Molecular Biosciences
 
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Citation counts: TR Web of Science Citation Count  Cited 32 times in Thomson Reuters Web of Science Article | Citations
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Created: Sat, 18 Apr 2009, 02:06:29 EST by Jennifer Falknau on behalf of School of Chemistry & Molecular Biosciences