The Journal of Neuroscience, April 8, 2009, 29(14):4442-4460; doi:10.1523/JNEUROSCI.6017-08.2009
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Neurobiology of Disease
Synaptic NMDA Receptor Activation Stimulates
-Secretase Amyloid Precursor Protein Processing and Inhibits Amyloid-β Production
Sarah E. Hoey,
Robert J. Williams, and
Michael S. Perkinton
King's College London, Wolfson Centre for Age-Related Diseases, London SE1 1UL, United Kingdom
Correspondence should be addressed to Dr. Michael S. Perkinton at his present address: Medical Research Council Centre for Neurodegeneration Research, Department of Neuroscience, PO37, Institute of Psychiatry, De Crespigny Park, London SE5 8AF, UK. Email: michael.perkinton{at}kcl.ac.uk
Altered amyloid precursor protein (APP) processing leading to increased production and oligomerization of Aβ may contribute to Alzheimer's disease (AD). Understanding how APP processing is regulated under physiological conditions may provide new insights into AD pathogenesis. Recent reports demonstrate that excitatory neural activity regulates APP metabolism and Aβ levels, although understanding of the molecular mechanisms involved is incomplete. We have investigated whether NMDA receptor activity regulates APP metabolism in primary cultured cortical neurons. We report that a pool of APP is localized to the postsynaptic compartment in cortical neurons and observed partial overlap of APP with both NR1 and PSD-95. NMDA receptor stimulation increased nonamyloidogenic
-secretase-mediated APP processing, as measured by a 2.5-fold increase in cellular
-C-terminal fragment (C83) levels after glutamate or NMDA treatment. This increase was blocked by the NMDA receptor antagonists D-AP5 and MK801 but not by the AMPA receptor antagonist CNQX or the L-type calcium channel blocker nifedipine, was prevented by chelation of extracellular calcium, and was blocked by the
-secretase inhibitor TAPI-1. Cotreatment of cortical neurons with bicuculline and 4-AP, which stimulates glutamate release and activates synaptic NMDA receptors, evoked an MK801-sensitive increase in C83 levels. Furthermore, NMDA receptor stimulation caused a twofold increase in the amount of soluble APP detected in the neuronal culture medium. Finally, NMDA receptor activity inhibited both Aβ1-40 release and Gal4-dependent luciferase activity induced by β-
-secretase-mediated cleavage of an APP-Gal4 fusion protein. Altogether, these data suggest that calcium influx through synaptic NMDA receptors promotes nonamyloidogenic
-secretase-mediated APP processing.
Received Dec. 18, 2008;
revised Feb. 3, 2009;
accepted Feb. 20, 2009.
Correspondence should be addressed to Dr. Michael S. Perkinton at his present address: Medical Research Council Centre for Neurodegeneration Research, Department of Neuroscience, PO37, Institute of Psychiatry, De Crespigny Park, London SE5 8AF, UK. Email: michael.perkinton{at}kcl.ac.uk
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Z. V. Goodger, L. Rajendran, A. Trutzel, B. M. Kohli, R. M. Nitsch, and U. Konietzko
Nuclear signaling by the APP intracellular domain occurs predominantly through the amyloidogenic processing pathway
J. Cell Sci.,
October 15, 2009;
122(20):
3703 - 3714.
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