Mutant prion protein enhances NMDA receptor activity, activates PKC, and triggers rapid excitotoxicity in mice
Joie Lin, … , John R. Yates III, Christina J. Sigurdson
Joie Lin, … , John R. Yates III, Christina J. Sigurdson
Published April 4, 2025
Citation Information: J Clin Invest. 2025;135(10):e186432. https://doi.org/10.1172/JCI186432.
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Research Article Aging Neuroscience

Mutant prion protein enhances NMDA receptor activity, activates PKC, and triggers rapid excitotoxicity in mice

Abstract

Neuronal hyperexcitability precedes synapse loss in certain neurodegenerative diseases, yet the synaptic membrane interactions and downstream signaling events remain unclear. The disordered amino terminus of the prion protein (PrPC) has been implicated in aberrant signaling in prion and Alzheimer’s disease. To disrupt neuronal interactions and signaling linked to the amino terminus, we CRISPR-engineered a knockin mouse expressing mutant PrPC (G92N), generating an N-linked glycosylation site between 2 functional motifs. Mice developed seizures and necrosis of hippocampal pyramidal neurons, similar to prion-infected mice and consistent with excitotoxicity. Phosphoproteomics analysis revealed phosphorylated glutamate receptors and calcium-sensitive kinases, including protein kinase C (PKC). Additionally, 92N-PrPC-expressing neurons showed persistent calcium influx as well as dendritic beading, which was rescued by an N-methyl-d-aspartate receptor (NMDAR) antagonist. Finally, survival of Prnp92N mice was prolonged by blocking active NMDAR channels. We propose that dysregulated PrPC-NMDAR–induced signaling can trigger an excitatory-inhibitory imbalance, spongiform degeneration, and neurotoxicity and that calcium dysregulation is central to PrPC-linked neurodegeneration.

Authors

Joie Lin, Julia A. Callender, Joshua E. Mayfield, Daniel B. McClatchy, Daniel Ojeda-Juárez, Mahsa Pourhamzeh, Katrin Soldau, Timothy D. Kurt, Garrett A. Danque, Helen Khuu, Josephina E. Ronson, Donald P. Pizzo, Yixing Du, Maxwell A. Gruber, Alejandro M. Sevillano, Jin Wang, Christina D. Orrú, Joy Chen, Gail Funk, Patricia Aguilar-Calvo, Brent D. Aulston, Subhojit Roy, Jong M. Rho, Jack D. Bui, Alexandra C. Newton, Stuart A. Lipton, Byron Caughey, Gentry N. Patrick, Kim Doré, John R. Yates III, Christina J. Sigurdson

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Figure 2

Targeting Prnp92N exclusively to neurons induces rapid neurodegeneration in mice.

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Targeting Prnp92N exclusively to neurons induces rapid neurodegeneration...
(A) Experimental design of the AAV constructs and i.v. injection into the superficial facial vein in P1 Prnp–/– mice. (B) Western blot and quantification of 92N-PrPC and WT-PrPC in brain lysates. (C) Survival curve for 92N-PrPC– and WT-PrPC–expressing mice (n = 4 and 5 for AAV-WT and AAV-92N, respectively). (D) Approximate age and survival of juvenile and adult Prnp–/– mice transduced with AAV-hSyn1Prnp92N (n = 4 and 3 per genotype for the juvenile and adult groups, respectively). Mice transduced with AAV-hSyn1PrnpWT did not show clinical signs. (E) Representative images of H&E-stained sections of hippocampus (CA1) (left and middle panels) and brainstem (right) show CA1 hippocampal necrosis and spongiform changes in 92N-PrPC–expressing mice. The boxed region in CA1 is shown at higher magnification (middle panel). Scale bars: 200 μm (left, right) and 50 μm (middle). Bar graphs show the mean ± SEM. **P < 0.01, by unpaired, 2-tailed t test with Welch’s correction (B), log-rank (Mantel-Cox) test (C), and Mann-Whitney U test (E). Illustrations in A and D were created with BioRender.com.