A cerebrospinal fluid synaptic protein biomarker for prediction of cognitive resilience versus decline in Alzheimer’s disease

Author(s): Oh, HS; Urey, DY; Karlsson, L; Zhu, Z; Shen, Y; Farinas, A; Timsina, J; Duggan, MR; Chen, J; Guldner, IH; Morshed, N; Yang, C; Western, D; Ali, M; Le Guen, Y; Trelle, A; Herukka, S; Rauramaa, T; Hiltunen, M; Lipponen, A; Luikku, AJ; Poston, KL; Mormino, E; Wagner, AD; Wilson, EN; Channappa, D; Leinonen, V; Stevens, B; Ehrenberg, AJ; Gottesman, RF; Coresh, J; Walker, KA; Zetterberg, H; Bennett, DA; Franzmeier, N; Hansson, O; Cruchaga, C; Wyss-Coray, T;
Year: 2025;  
Journal: Nature Medicine;  
Volume: 31;  
Issue: 5;  
Abstract:

Rates of cognitive decline in Alzheimer’s disease (AD) are extremely heterogeneous. Although biomarkers for amyloid-beta (Aβ) and tau proteins, the hallmark AD pathologies, have improved pathology-based diagnosis, they explain only 20-40% of the variance in AD-related cognitive impairment (CI). To discover novel biomarkers of CI in AD, we performed cerebrospinal fluid (CSF) proteomics on 3,397 individuals from six major prospective AD case-control cohorts. Synapse proteins emerged as the strongest correlates of CI, independent of Aβ and tau. Using machine learning, we derived the CSF YWHAG:NPTX2 synapse protein ratio, which explained 27% of the variance in CI beyond CSF pTau181:Aβ42, 11% beyond tau positron emission tomography, and 28% beyond CSF neurofilament, growth-associated protein 43 and neurogranin in Aβ+ and phosphorylated tau+ (A+T1+) individuals. CSF YWHAG:NPTX2 also increased with normal aging and 20 years before estimated symptom onset in carriers of autosomal dominant AD mutations. Regarding cognitive prognosis, CSF YWHAG:NPTX2 predicted conversion from A+T1+ cognitively normal to mild cognitive impairment (standard deviation increase hazard ratio = 3.0, P = 7.0 × 10-4) and A+T1+ mild cognitive impairment to dementia (standard deviation increase hazard ratio = 2.2, P = 8.2 × 10-16) over a 15-year follow-up, adjusting for CSF pTau181:Aβ42, CSF neurofilament, CSF neurogranin, CSF growth-associated protein 43, age, APOE4 and sex. We also developed a plasma proteomic signature of CI, which we evaluated in 13,401 samples, which partly recapitulated CSF YWHAG:NPTX2. Overall, our findings underscore CSF YWHAG:NPTX2 as a robust prognostic biomarker for cognitive resilience versus AD onset and progression, highlight the potential of plasma proteomics in replacing CSF measurement and further implicate synapse dysfunction as a core driver of AD dementia.