Abstract
BACKGROUND: Biofluid proteomics can enhance our understanding of the neurodegenerative mechanisms underlying Alzheimer's disease and related dementias (ADRDs). Oligodendrocyte myelin glycoprotein (OMG) is a brain-specific protein implicated in myelination, but its potential mechanistic, biomarker, and therapeutic roles in ADRDs requires further elucidation. METHODS: After detecting an inverse association between its abundance in peripheral circulation and cortical amyloid deposition in two community-based cohorts, the current study characterized OMG's role in ADRDs with high-throughput proteomics from sixteen independent cohorts. Data included a variety of cross-sectional and longitudinal community-based and clinical cohorts from North America, Europe, and Asia, and incorporated complementary biofluids, biospecimens, and proteomic platforms. Statistical analyses were conducted separately in each cohort. RESULTS: We detected lower plasma OMG in individuals with cortical amyloid deposition, compromised brain structure, dementia, and multiple sclerosis, as well as in individuals who developed dementia over 7- to 20-year follow-up periods. OMG's CSF and brain proteomic signatures reflected broader neuroprotective mechanisms, especially axonal structural integrity, and two-sample Mendelian randomization causally implicated OMG as protective against multiple neurodegenerative diseases. CONCLUSIONS: Our findings implicate OMG as a mechanistic determinant of neurodegenerative resiliency among older adults, which is reliably captured by its abundance in peripheral circulation.