Journal Article

Myelin dysfunction drives amyloid-β deposition in models of Alzheimer’s disease

Willem, Michael, Ruhwedel, Torben, Nave, Klaus-Armin, Wirths, Oliver, Zampar, Silvia, Simons, Mikael, Subramanian, Swati, Werner, Hauke B., Stassart, Ruth, Overhoff, Katharina, Spieth, Lena, Ehrenreich, Hannelore, Kawaguchi, Riki, Geschwind, Daniel, Arinrad, Sahab, Haass, Christian, Sun, Ting, Saher, Gesine, Saito, Takashi, Möbius, Wiebke, Saido, Takaomi, Depp, Constanze, Krueger-Burg, Dilja, Steixner-Kumar, Agnes A., Nazarenko, Taisiia, Berghoff, Stefan A., Damkou, Alkmini, Thalmann, Maik, Sasmita, Andrew Octavian, Göbbels, Sandra

2023

Overview

The incidence of Alzheimer’s disease (AD), the leading cause of dementia, increases rapidly with age, but why age constitutes the main risk factor is still poorly understood. Brain ageing affects oligodendrocytes and the structural integrity of myelin sheaths 1 , the latter of which is associated with secondary neuroinflammation 2 , 3 . As oligodendrocytes support axonal energy metabolism and neuronal health 4 – 7 , we hypothesized that loss of myelin integrity could be an upstream risk factor for neuronal amyloid-β (Aβ) deposition, the central neuropathological hallmark of AD. Here we identify genetic pathways of myelin dysfunction and demyelinating injuries as potent drivers of amyloid deposition in mouse models of AD. Mechanistically, myelin dysfunction causes the accumulation of the Aβ-producing machinery within axonal swellings and increases the cleavage of cortical amyloid precursor protein. Suprisingly, AD mice with dysfunctional myelin lack plaque-corralling microglia despite an overall increase in their numbers. Bulk and single-cell transcriptomics of AD mouse models with myelin defects show that there is a concomitant induction of highly similar but distinct disease-associated microglia signatures specific to myelin damage and amyloid plaques, respectively. Despite successful induction, amyloid disease-associated microglia (DAM) that usually clear amyloid plaques are apparently distracted to nearby myelin damage. Our data suggest a working model whereby age-dependent structural defects of myelin promote Aβ plaque formation directly and indirectly and are therefore an upstream AD risk factor. Improving oligodendrocyte health and myelin integrity could be a promising target to delay development and slow progression of AD. Mouse models show that myelin dysfunction and associated inflammation increase with age, which can promote amyloid-β deposition and therefore risk of developing Alzheimer’s disease.

• Publisher: Nature Publishing Group UK,Nature Publishing Group
• Subject: 14 / 14/63 / 38/91 / 631/378/1689/1283 / 631/378/2596/1705 / 64/60 / Age / Aging / Alzheimer Disease - metabolism / Alzheimer Disease - pathology / Alzheimer's disease / Amyloid beta-Peptides - metabolism / Amyloid precursor protein / Amyloidosis / Animal models / Animals / Axons - metabolism / Axons - pathology / Brain / Brain injury / Cell culture / Damage / Defects / Dementia disorders / Demyelination / Deposition / Disease Models, Animal / Disease Progression / Energy metabolism / Humanities and Social Sciences / Hypotheses / Inflammation / Mice / Microglia / Microglia - metabolism / Microglia - pathology / Microscopy / Modelling / multidisciplinary / Myelin / Myelin Sheath - metabolism / Myelin Sheath - pathology / Neurodegenerative diseases / Oligodendrocytes / Pathology / Plaque, Amyloid - genetics / Plaque, Amyloid - metabolism / Plaque, Amyloid - pathology / Proteins / Risk Factors / Science / Science (multidisciplinary) / Senile plaques / Single-Cell Gene Expression Analysis / Structural integrity / Transcriptomics / Upstream / β-Amyloid