Plasma proteomic signatures of preclinical Alzheimer’s disease biomarkers and memory in clinically unimpaired older adults

Product:
CNS Disease Panel 120
Topic:
Neurology
Disease Area:
Alzheimer's Disease
Sample Type:
Plasma
Topic/Product:
CNS Disease Panel 120
Disease Area:
Alzheimer's Disease
Sample Type:
Plasma

Abstract

Background Multianalyte plasma proteomic panels that can accurately detect initial AD pathology in preclinical populations and simultaneously measure related biological processes relevant for disease risk are critical for advancing early detection and prognosis.

Methods Using the NULISAseq CNS panel, we measured plasma from 193 clinically unimpaired (CU) older adults enrolled in the Stanford Aging and Memory Study (SAMS). We evaluated correspondence of core AD-relevant biomarkers Aβ42, Aβ40, pTau217, pTau181, GFAP, NfL, Aβ42/Aβ40, and pTau217/Aβ42 measured using NULISAseq and established Lumipulse immunoassays. ROC curve analyses compared the accuracy of these biomarkers for detecting Lumipulse CSF Aβ-positivity across platforms. Linear models were applied across 124 NULISAseq proteins to examine associations with common AD risk factors, including age, female sex, and APOE-ε4, as well as with biomarkers CSF Aβ42/Aβ40 and pTau181, 18F-PI2620 Tau PET, and memory. Fold change differences in NULISAseq proteins as a function of CSF Aβ (A+) and pTau181 (T+) status were examined using Wilcoxon rank-sum tests.

Results Moderate to high correlations were observed between NULISAseq and Lumipulse AD plasma biomarkers. Across platforms, plasma pTau217/Aβ42 exhibited the highest performance in discriminating CSF A+ (NULISAseq AUC: 0.940, 95%CI: 0.885-0.995; Lumipulse AUC: 0.907, 95%CI: 0.849-0.966). Age and sex were associated with differential expression of NULISAseq targets linked to neurodegeneration, microglial activation, and inflammation. CSF A+ was associated with fold change differences in Aβ42, pTau217, pTau231, pTau181, and GFAP, while CSF T+ was additionally associated with increases in TREM1, TIMP3, SAA1, and S100A12. When stratified by AT groups, A+T-exhibited lower Aβ42 and elevated pTau217 compared to A-T-, whereas A+T+ exhibited elevated pTau231 and pTau181 compared to A+T-. Temporal cortex tau was positively associated with NULISAseq pTau217, pTau231, pTau181, and pTau217/Aβ42. Memory function was negatively associated with pTau isoforms and PRDX6, YWHAZ, ENO2, ARSA, CHI3L1, CXCL8, and FCN2. These associations remained when controlling for pTau217 and restricting to A-CU, suggesting these targets may represent AD-independent biological pathways relevant for memory function.

Conclusions NULISAseq immunoassay-based multiplexing accurately detects AD pathology among CU older adults and identifies multiple biological pathways related to early biomarker abnormality and memory function that may become dysregulated in preclinical AD.

Authors & Affiliations

Alexandra N Trelle1, Karly A Cody1, Tran T Nguyen2, Joseph R Winer1, Skylar Weiss1, Isha Sai1, Divya Channappa1, Justin Mendiola1, Amal Al-Rajhi1, Keerthana Raghuraman1, Sharon J Sha1, Edward N Wilson1,3,4, Tony Wyss-Coray1,3,4, Anthony D Wagner3,5, Holden T Maecker6, Elizabeth C Mormino1,3,7

Affiliations:
1. Department of Neurology & Neurological Sciences, Stanford University School of Medicine,
Stanford, CA 94305
2. Institute for Immunity, Transplantation, and Infection Operations, Stanford University
3. Wu Tsai Neurosciences Institute, Stanford University, Stanford, CA 94305
4. Phil and Penny Knight Initiative for Brain Resilience, Stanford University, Stanford, CA 94305
5. Department of Psychology, Stanford University, Stanford, CA 94305
6. Department of Microbiology and Immunology, Stanford University
7. Molecular Imaging Program at Stanford (MIPS), Stanford University, Stanford, CA 94305

Steve Williams, MD, PhD

CSO

Dr. Willams serves as the company’s Chief Scientific Officer. He was previously Chief Medical Officer at Standard Biotools and at SomaLogic where he pioneered the discipline for discovery and validation of predictive, diagnostic and prognostic models using machine-learning applied to large-plex proteomics. 20 such tests were used for drug characterization, safety and efficacy when incorporated in clinical drug trials at Pharma/Biotech and 17 different multivariate tests were validated and translated into regulated healthcare uses. Prior to SomaLogic, Dr. Williams was at Pfizer in the UK and the USA as a clinical triallist in Translational Medicine, and subsequently as VP, Global Clinical Technology. He sat on the National Advisory Council for the National Institute of Biomedical Imaging and Bioengineering, the Executive Committee for the FNIH Biomarkers Consortium, and worked with FDA and PhRMA on developing evidentiary standards for biomarker qualification. Dr. William’s medical training was in London, at Charing Cross and Westminster Medical School, followed by a PhD in medicine/physiology at the same institution and training in Radiology at the University of Newcastle Upon Tyne. Steve is co-inventor on 26 proteomics patents and author/coauthor on multiple foundational proteomics manuscripts.

Justin McAnear

CFO

Mr. McAnear serves as the company’s Chief Financial Officer. He brings over 25 years of operational and financial leadership experience across various sectors and was instrumental in taking 10x Genomics public in 2019, serving as its CFO for over five years. Mr. McAnear served for over 3 years as Tesla’s VP of Worldwide Finance and Operations, supporting landmark initiatives such as the Model X and Model 3 launches and Solar City acquisition.  He also held various roles at Apple and J&J earlier in his career and served as a naval officer and aviator for over 9 years.