This project was funded by NIA (R01AG064786, 9/1/2019-4/30/2024, PI: Jinying Zhao). The objectives of this project are to generate the first detailed map of brain 6mA methylome and identify causative genes harboring aberrant 6mA alterations associated with quantitative neuropathological measures for early features of AD pathology (e.g., amyloid plaques, neurofibrillary tangles). To achieve this, we propose three specific aims: (1) Genome-wide mapping of brain DNA 6mA methylome to identify differentially methylated genes/regions harboring altered 6mA sites (D6AMRs) associated with AD pathology in 1,200 postmortem brain tissue samples collected by two large, community-based population cohorts of aging and dementia. (2) Integrated multiomics analysis to elucidate the potential mechanistic role of 6mA alteration in AD pathology; and (3) Functionally validation of top-ranked candidate genes in 3D brain organoids derived from human iPSCs.