The Journal of Neuroscience, August 26, 2009, 29(34):10627-10637; doi:10.1523/JNEUROSCI.0620-09.2009
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Neurobiology of Disease
The p75 Neurotrophin Receptor Promotes Amyloid-β(1-42)-Induced Neuritic Dystrophy In Vitro and In Vivo
Juliet K. Knowles,1,3
Jayakumar Rajadas,1,2
Thuy-Vi V. Nguyen,1
Tao Yang,1,3
Melburne C. LeMieux,2
Lilith Vander Griend,1
Chihiro Ishikawa,1,4
Stephen M. Massa,5,6
Tony Wyss-Coray,1,4 and
Frank M. Longo1,3
Departments of 1Neurology and Neurological Science, and 2Chemical Engineering, Stanford University, Stanford, California 94305, 3Department of Neurology, University of North Carolina–Chapel Hill, Chapel Hill, North Carolina 27599, 4Palo Alto Veterans Affairs Health Care System, Palo Alto, California 94304, 5Department of Neurology and Laboratory for Computational Neurochemistry and Drug Discovery, Department of Veterans Affairs Medical Center, San Francisco, and 6Department of Neurology, University of California, San Francisco, San Francisco, California 94121
Correspondence should be addressed to Dr. Frank M. Longo, Department of Neurology and Neurological Sciences, Stanford University School of Medicine, 300 Pasteur Drive, Room H3160, Stanford, CA 94305. Email: longo{at}stanford.edu
Oligomeric forms of amyloid-β (Aβ) are thought to play a causal role in Alzheimer's disease (AD), and the p75 neurotrophin receptor (p75NTR) has been implicated in Aβ-induced neurodegeneration. To further define the functions of p75NTR in AD, we examined the interaction of oligomeric Aβ(1-42) with p75NTR, and the effects of that interaction on neurite integrity in neuron cultures and in a chronic AD mouse model. Atomic force microscopy was used to ascertain the aggregated state of Aβ, and fluorescence resonance energy transfer analysis revealed that Aβ oligomers interact with the extracellular domain of p75NTR. In vitro studies of Aβ-induced death in neuron cultures isolated from wild-type and p75NTR–/– mice, in which the p75NTR extracellular domain is deleted, showed reduced sensitivity of mutant cells to Aβ-induced cell death. Interestingly, Aβ-induced neuritic dystrophy and activation of c-Jun, a known mediator of Aβ-induced deleterious signaling, were completely prevented in p75NTR–/– neuron cultures. Thy1-hAPPLond/Swe x p75NTR–/– mice exhibited significantly diminished hippocampal neuritic dystrophy and complete reversal of basal forebrain cholinergic neurite degeneration relative to those expressing wild-type p75NTR. Aβ levels were not affected, suggesting that removal of p75NTR extracellular domain reduced the ability of excess Aβ to promote neuritic degeneration. These findings indicate that although p75NTR likely does not mediate all Aβ effects, it does play a significant role in enabling Aβ-induced neurodegeneration in vitro and in vivo, establishing p75NTR as an important therapeutic target for AD.
Received Feb. 5, 2009;
revised June 16, 2009;
accepted July 14, 2009.
Correspondence should be addressed to Dr. Frank M. Longo, Department of Neurology and Neurological Sciences, Stanford University School of Medicine, 300 Pasteur Drive, Room H3160, Stanford, CA 94305. Email: longo{at}stanford.edu