TY - JOUR
T1 - Reduced neuronal expression of synaptic transmission modulator HNK-1/neural cell adhesion molecule as a potential consequence of amyloid β-mediated oxidative stress
T2 - A proteomic approach
AU - Thomas, Stefani N.
AU - Soreghan, Brian A.
AU - Nistor, Mihaela
AU - Sarsoza, Floyd
AU - Head, Elizabeth
AU - Yang, Austin J.
PY - 2005/2
Y1 - 2005/2
N2 - Oxidative stress imparted by reactive oxygen species (ROS) is implicated in the pathogenesis of Alzheimer's disease (AD). Given that amyloid β (Aβ) itself generates ROS that can directly damage proteins, elucidating the functional consequences of protein oxidation can enhance our understanding of the process of Aβ-mediated neurodegeneration. In this study, we employed a biocytin hydrazide/streptavidin affinity purification methodology followed by two-dimensional liquid chromatography tandem mass spectrometry coupled with SEQUEST bioinformatics technology, to identify the targets of Aβ-induced oxidative stress in cultured primary cortical mouse neurons. The Golgi-resident enzyme glucuronyltransferase (GlcAT-P) was a carbonylated target that we investigated further owing to its involvement in the biosynthesis of HNK-1, a carbohydrate epitope expressed on cell adhesion molecules and implicated in modulating the effectiveness of synaptic transmission in the brain. We found that increasing amounts of Aβ, added exogenously to the culture media of primary cortical neurons, significantly decreased HNK-1 expression. Moreover, in vivo, HNK-1 immunoreactivity was decreased in brain tissue of a transgenic mouse model of AD. We conclude that a potential consequence of Aβ-mediated oxidation of GlcAT-P is impairment of its enzymatic function, thereby disrupting HNK-1 biosynthesis and possibly adversely affecting synaptic plasticity. Considering that AD is partly characterized by progressive memory impairment and disordered cognitive function, the data from our in vitro studies can be reconciled with results from in vivo studies that have demonstrated that HNK-1 modulates synaptic plasticity and is critically involved in memory consolidation.
AB - Oxidative stress imparted by reactive oxygen species (ROS) is implicated in the pathogenesis of Alzheimer's disease (AD). Given that amyloid β (Aβ) itself generates ROS that can directly damage proteins, elucidating the functional consequences of protein oxidation can enhance our understanding of the process of Aβ-mediated neurodegeneration. In this study, we employed a biocytin hydrazide/streptavidin affinity purification methodology followed by two-dimensional liquid chromatography tandem mass spectrometry coupled with SEQUEST bioinformatics technology, to identify the targets of Aβ-induced oxidative stress in cultured primary cortical mouse neurons. The Golgi-resident enzyme glucuronyltransferase (GlcAT-P) was a carbonylated target that we investigated further owing to its involvement in the biosynthesis of HNK-1, a carbohydrate epitope expressed on cell adhesion molecules and implicated in modulating the effectiveness of synaptic transmission in the brain. We found that increasing amounts of Aβ, added exogenously to the culture media of primary cortical neurons, significantly decreased HNK-1 expression. Moreover, in vivo, HNK-1 immunoreactivity was decreased in brain tissue of a transgenic mouse model of AD. We conclude that a potential consequence of Aβ-mediated oxidation of GlcAT-P is impairment of its enzymatic function, thereby disrupting HNK-1 biosynthesis and possibly adversely affecting synaptic plasticity. Considering that AD is partly characterized by progressive memory impairment and disordered cognitive function, the data from our in vitro studies can be reconciled with results from in vivo studies that have demonstrated that HNK-1 modulates synaptic plasticity and is critically involved in memory consolidation.
KW - Amyloid-β
KW - Glucuronyltransferase
KW - Human Natural Killer (HNK-1)
KW - Liquid chromatography tandem mass spectrometry
KW - Oxidative stress
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U2 - 10.1111/j.1471-4159.2004.02892.x
DO - 10.1111/j.1471-4159.2004.02892.x
M3 - Article
C2 - 15686472
AN - SCOPUS:13644259768
SN - 0022-3042
VL - 92
SP - 705
EP - 717
JO - Journal of Neurochemistry
JF - Journal of Neurochemistry
IS - 4
ER -