A multi-omics approach identifies a blood-based miRNA signature of cognitive decline in two large observational trials

Identifying individuals before the onset of overt symptoms is a key prerequisite for the prevention of Alzheimer’s disease (AD). A wealth of data reports dysregulated microRNA (miRNA) expression in the blood of individuals with AD, but evidence in individuals at subclinical stages is sparse. In this study, a qPCR analysis of a prioritised set of 38 candidate miRNAs in the blood of 830 healthy individuals from the CHARIOT PRO cohort (West London, UK) was undertaken. Here, we identified six differentially expressed miRNAs (hsa-miR-128-3p, hsa-miR-144-5p, hsa-miR-146a-5p, hsa-miR-26a-5p, hsa-miR-29c-3p and hsa-miR-363-3p) in the blood of individuals with low cognitive performance on the Repeatable Battery for the Assessment of Neuropsychological Status (RBANS). A pathway enrichment analysis for the six miRNAs indicated involvement of apoptosis and inflammation, relevant in early AD stages. Subsequently, we used whole genome sequencing (WGS) data from 750 individuals from the AD Neuroimaging Initiative (ADNI) to perform a genetic association analysis for polymorphisms within the significant miRNAs’ genes and CSF concentrations of phosphorylated-tau, total-tau, amyloid-β42 and soluble-TREM2 and BACE1 activity. Our analysis revealed 24 SNPs within MIR29C to be associated with CSF levels of amyloid-β42 and soluble-TREM2 and BACE1 activity. Our study shows the potential of a six-miRNA set as diagnostic blood biomarker of subclinical cognitive deficits in AD. Polymorphisms within MIR29C suggest a possible interplay between the amyloid cascade and microglial activation at preclinical stages of AD. ### Competing Interest Statement The authors have declared no competing interest. ### Funding Statement The authors thank Janssen Pharmaceuticals Research & Development LLC. for funding CHARIOT PRO. The miRNA qPCR analysis was funded by Stevenage Bioscience Catalyst. For the ADNI, data collection and sharing for this project was funded by the Alzheimer s Disease Neuroimaging Initiative (ADNI) (National Institutes of Health Grant U01 AG024904) and DOD ADNI (Department of Defense award number W81XWH-12-2-0012). ADNI is funded by the National Institute on Aging, the National Institute of Biomedical Imaging and Bioengineering and through generous contributions of: AbbVie, Alzheimer s Association; Alzheimer s Drug Discovery Foundation; Araclon Biotech; BioClinica, Inc.; Biogen; Bristol-Myers Squibb Company; CereSpir, Inc.; Cogstate; Eisai Inc.; Elan Pharmaceuticals, Inc.; Eli Lilly and Company; EuroImmun; F. Hoffmann-La Roche Ltd and its affiliated company Genentech, Inc.; Fujirebio; GE Healthcare; IXICO Ltd.; Janssen Alzheimer Immunotherapy Research & Development, LLC.; Johnson & Johnson Pharmaceutical Research & Development LLC.; Lumosity; Lundbeck; Merck & Co., Inc.; Meso Scale Diagnostics, LLC.; NeuroRx Research; Neurotrack Technologies; Novartis Pharmaceuticals Corporation; Pfizer Inc.; Piramal Imaging; Servier; Takeda Pharmaceutical Company; and Transition Therapeutics. The Canadian Institutes of Health Research is providing funds to support ADNI clinical sites in Canada. Private sector contributions are facilitated by the Foundation for the National Institutes of Health ([www.fnih.org][1]). The grantee organization is the Northern California Institute for Research and Education, and the study is coordinated by the Alzheimer s Therapeutic Research Institute at the University of Southern California. ADNI data are disseminated by the Laboratory for Neuro Imaging at the University of Southern California. A.S received funding from the Imperial College London President s PhD Scholarship (2017-2021). I.P. is funded by the Diabetes UK (BDA number: 20/0006307), the European Union s Horizon 2020 research and innovation programme (LONGITOOLS, H2020-SC1-2019-874739), Agence Nationale de la Recherche (PreciDIAB, ANR-18-IBHU-0001), by the European Union through the Fonds europeen de developpement regional (FEDER), by the Conseil Regional des Hauts-de-France (Hauts-de-France Regional Council) and by the Metropole Europeenne de Lille (MEL, European Metropolis of Lille). ### Author Declarations I confirm all relevant ethical guidelines have been followed, and any necessary IRB and/or ethics committee approvals have been obtained. Yes The details of the IRB/oversight body that provided approval or exemption for the research described are given below: CHARIOT PRO: The Chariot-Pro Main study has received National Research Ethics Services approval (15/L0/0711) and internal Imperial College London (ICL) Research Ethics, Joint Research Compliance Office approval (JRCO:15/1C/2791). ADNI: ADNI obtained all IRB approvals and met all ethical standards. The Ethics committees/institutional review boards that approved the ADNI study are: Albany Medical Center Committee on Research Involving Human Subjects Institutional Review Board, Boston University Medical Campus and Boston Medical Center Institutional Review Board, Butler Hospital Institutional Review Board, Cleveland Clinic Institutional Review Board, Columbia University Medical Center Institutional Review Board, Duke University Health System Institutional Review Board, Emory Institutional Review Board, Georgetown University Institutional Review Board, Health Sciences Institutional Review Board, Houston Methodist Institutional Review Board, Howard University Office of Regulatory Research Compliance, Icahn School of Medicine at Mount Sinai Program for the Protection of Human Subjects, Indiana University Institutional Review Board, Institutional Review Board of Baylor College of Medicine, Jewish General Hospital Research Ethics Board, Johns Hopkins Medicine Institutional Review Board, Lifespan - Rhode Island Hospital Institutional Review Board, Mayo Clinic Institutional Review Board, Mount Sinai Medical Center Institutional Review Board, Nathan Kline Institute for Psychiatric Research & Rockland Psychiatric Center Institutional Review Board, New York University Langone Medical Center School of Medicine Institutional Review Board, Northwestern University Institutional Review Board, Oregon Health and Science University Institutional Review Board, Partners Human Research Committee Research Ethics, Board Sunnybrook Health Sciences Centre, Roper St. Francis Healthcare Institutional Review Board, Rush University Medical Center Institutional Review Board, St. Joseph's Phoenix Institutional Review Board, Stanford Institutional Review Board, The Ohio State University Institutional Review Board, University Hospitals Cleveland Medical Center Institutional Review Board, University of Alabama Office of the IRB, University of British Columbia Research Ethics Board, University of California Davis Institutional Review Board Administration, University of California Los Angeles Office of the Human Research Protection Program, University of California San Diego Human Research Protections Program, University of California San Francisco Human Research Protection Program, University of Iowa Institutional Review Board, University of Kansas Medical Center Human Subjects Committee, University of Kentucky Medical Institutional Review Board, University of Michigan Medical School Institutional Review Board, University of Pennsylvania Institutional Review Board, University of Pittsburgh Institutional Review Board, University of Rochester Research Subjects Review Board, University of South Florida Institutional Review Board, University of Southern, California Institutional Review Board, UT Southwestern Institution Review Board, VA Long Beach Healthcare System Institutional Review Board, Vanderbilt University Medical Center Institutional Review Board, Wake Forest School of Medicine Institutional Review Board, Washington University School of Medicine Institutional Review Board, Western Institutional Review Board, Western University Health Sciences Research Ethics Board, and Yale University Institutional Review Board. I confirm that all necessary patient/participant consent has been obtained and the appropriate institutional forms have been archived, and that any patient/participant/sample identifiers included were not known to anyone (e.g., hospital staff, patients or participants themselves) outside the research group so cannot be used to identify individuals. Yes I understand that all clinical trials and any other prospective interventional studies must be registered with an ICMJE-approved registry, such as ClinicalTrials.gov. I confirm that any such study reported in the manuscript has been registered and the trial registration ID is provided (note: if posting a prospective study registered retrospectively, please provide a statement in the trial ID field explaining why the study was not registered in advance). Yes I have followed all appropriate research reporting guidelines and uploaded the relevant EQUATOR Network research reporting checklist(s) and other pertinent material as supplementary files, if applicable. Yes All data produced in the present work are contained in the manuscript [1]: http://www.fnih.org