Anatomy and Cell Biology Publications
Document Type
Article
Publication Date
10-16-2013
Issue
42
Journal
JOURNAL OF NEUROSCIENCE
Volume
33
First Page
16552
Last Page
16564
URL with Digital Object Identifier
10.1523/JNEUROSCI.3214-13.2013
Abstract
In Alzheimer's disease (AD), soluble amyloid-beta oligomers (A beta Os) trigger neurotoxic signaling, at least partially, via the cellular prion protein (PrPC). However, it is unknown whether other ligands of PrPC can regulate this potentially toxic interaction. Stress-inducible phosphoprotein 1 (STI1), an Hsp90 cochaperone secreted by astrocytes, binds to PrPC in the vicinity of the A beta O binding site to protect neurons against toxic stimuli. Here, we investigated a potential role of STI1 in A beta O toxicity. We confirmed the specific binding of A beta Os and STI1 to the PrP and showed that STI1 efficiently inhibited A beta O binding to PrP in vitro (IC50 of similar to 70 nM) and also decreased A beta O binding to cultured mouse primary hippocampal neurons. Treatment with STI1 prevented A beta O-induced synaptic loss and neuronal death in mouse cultured neurons and long-term potentiation inhibition in mouse hippocampal slices. Interestingly, STI1-haploinsufficient neurons were more sensitive to A beta O-induced cell death and could be rescued by treatment with recombinant STI1. Noteworthy, both A beta O binding to PrPC and PrPC-dependent A beta O toxicity were inhibited by TPR2A, the PrPC-interacting domain of STI1. Additionally, PrPC-STI1 engagement activated alpha 7 nicotinic acetylcholine receptors, which participated in neuroprotection against A beta O-induced toxicity. We found an age-dependent upregulation of cortical STI1 in the APPswe/PS1dE9 mouse model of AD and in the brains of AD-affected individuals, suggesting a compensatory response. Our findings reveal a previously unrecognized role of the PrPC ligand STI1 in protecting neurons in AD and suggest a novel pathway that may help to offset A beta O-induced toxicity.
