Genome-Wide Mapping Implicates 5-Hydroxymethylcytosines in Diabetes Mellitus and Alzheimer’s Disease

Article type: Research Article

Authors: Beadell, Alana V.^{a; 1} | Zhang, Zhou^{b; 1} | Capuano, Ana W.^c | Bennett, David A.^c | He, Chuan^{d; e} | Zhang, Wei^{b; *} | Arvanitakis, Zoe^{c; *}

Affiliations: [a] Department of Chemistry, The University of Chicago, Chicago, IL, USA | [b] Department of Preventive Medicine, Northwestern University Feinberg School of Medicine, Chicago, IL, USA | [c] Rush Alzheimer’s Disease Center, Rush University Medical Center, Chicago, IL, USA | [d] Department of Chemistry, Department of Biochemistry and Molecular Biology, Institute for Biophysical Dynamics, The University of Chicago, Chicago, IL, USA | [e] Howard Hughes Medical Institute, The University of Chicago, Chicago, IL, USA

Correspondence: [*] Correspondence to: Zoe Arvanitakis, MD, MS, Rush Alzheimer’s Disease Center, Rush University Medical Center 1750 W. Harrison St., Suite 1000, Chicago, IL 60612, USA. Tel.: +1 312 942 2028; and Wei Zhang, PhD, Department of Preventive Medicine, Northwestern University Feinberg School of Medicine, 680 N. Lake Shore Dr., Suite 1400, Chicago, IL 60611 USA. Tel.: +1 312 503 1040; E-mail: wei.zhang1@northwestern.edu.

Note: [1] These authors contributed equally.

Abstract: Background:Diabetes mellitus (DM) is a recognized risk factor for dementia. Because DM is a potentially modifiable condition, greater understanding of the mechanisms linking DM to the clinical expression of Alzheimer’s disease dementia may provide insights into much needed dementia therapeutics. Objective:In this feasibility study, we investigated DM as a dementia risk factor by examining genome-wide distributions of the epigenetic DNA modification 5-hydroxymethylcytosine (5hmC). Methods:We obtained biologic samples from the Rush Memory and Aging Project and used the highly sensitive 5hmC-Seal technique to perform genome-wide profiling of 5hmC in circulating cell-free DNA (cfDNA) from antemortem serum samples and in genomic DNA from postmortem prefrontal cortex brain tissue from 80 individuals across four groups: Alzheimer’s disease neuropathologically defined (AD), DM clinically defined, AD with DM, and individuals with neither disease (controls). Results:Distinct 5hmC signatures and biological pathways were enriched in persons with both AD and DM versus AD alone, DM alone, or controls, including genes inhibited by EGFR signaling in oligodendroglia and those activated by constitutive RHOA. We also demonstrate the potential diagnostic value of 5hmC profiling in circulating cfDNA. Specifically, an 11-gene weighted model distinguished AD from non-AD/non-DM controls (AUC = 91.8%; 95% CI, 82.9–100.0%), while a 4-gene model distinguished DM-associated AD from AD alone (AUC = 87.9%; 95% CI, 77.5–98.3%). Conclusion:We demonstrate in this small sample, the feasibility of detecting and characterizing 5hmC in DM-associated AD and of using 5hmC information contained in circulating cfDNA to detect AD in high-risk individuals, such as those with diabetes.

Keywords: Alzheimer’s disease, cell-free DNA, dementia, diabetes mellitus, epigenetics, 5-hydroxymethylcytosine

DOI: 10.3233/JAD-221113

Journal: Journal of Alzheimer's Disease, vol. 93, no. 3, pp. 1135-1151, 2023