Methylomic signatures of tau and beta amyloid in transgenic mouse models of Alzheimer’s disease neuropathology [HorvathMammalMethylChip40 Methylation Beadchip]
Ontology highlight
ABSTRACT: We identified widespread DNA methylation changes associated with the development of both tau and amyloid neuropathology, including differentially methylated positions (DMPs) and regions (DMRs) at loci previously implicated in AD and overlapping changes identified in our ongoing analyses of human post-mortem AD brains.
ORGANISM(S): Mus musculus Rattus norvegicus Homo sapiens
Project description:We identified widespread DNA methylation changes associated with the development of both tau and amyloid neuropathology, including differentially methylated positions (DMPs) and regions (DMRs) at loci previously implicated in AD and overlapping changes identified in our ongoing analyses of human post-mortem AD brains.
Project description:Alzheimer’s disease (AD) is a chronic neurodegenerative disorder that is characterized by progressive neuropathology and cognitive decline. We performed a cross-tissue analysis of methylomic variation in AD using samples from three independent human post-mortem brain cohorts. We identified a differentially methylated region in the ankyrin 1 (ANK1) gene that was associated with neuropathology in the entorhinal cortex, a primary site of AD manifestation. This region was confirmed as being substantially hypermethylated in two other cortical regions (superior temporal gyrus and prefrontal cortex), but not in the cerebellum, a region largely protected from neurodegeneration in AD, or whole blood obtained pre-mortem from the same individuals. Neuropathology-associated ANK1 hypermethylation was subsequently confirmed in cortical samples from three independent brain cohorts. This study represents, to the best of our knowledge, the first epigenome-wide association study of AD employing a sequential replication design across multiple tissues and highlights the power of this approach for identifying methylomic variation associated with complex disease. For the first (discovery) stage of our analysis, we used multiple tissues from donors (N = 122) archived in the MRC London Brainbank for Neurodegenerative Disease. From each donor, we isolated genomic DNA from four brain regions (EC, superior temporal gyrus (STG), prefrontal cortex (PFC) and CER) and, where available, from whole blood obtained pre-mortem. Our analyses focused on identifying differentially methylated positions (DMPs) associated with Braak staging, a standardized measure of neurofibrillary tangle burden determined at autopsy.
Project description:Alzheimer’s disease (AD) is a chronic neurodegenerative disorder that is characterized by progressive neuropathology and cognitive decline. We performed a cross-tissue analysis of methylomic variation in AD using samples from three independent human post-mortem brain cohorts. We identified a differentially methylated region in the ankyrin 1 (ANK1) gene that was associated with neuropathology in the entorhinal cortex, a primary site of AD manifestation. This region was confirmed as being substantially hypermethylated in two other cortical regions (superior temporal gyrus and prefrontal cortex), but not in the cerebellum, a region largely protected from neurodegeneration in AD, or whole blood obtained pre-mortem from the same individuals. Neuropathology-associated ANK1 hypermethylation was subsequently confirmed in cortical samples from three independent brain cohorts. This study represents, to the best of our knowledge, the first epigenome-wide association study of AD employing a sequential replication design across multiple tissues and highlights the power of this approach for identifying methylomic variation associated with complex disease.
Project description:Alzheimer’s disease (AD) is characterized by memory loss and neuropsychiatric symptoms associated with cerebral accumulation of amyloid-β (Aβ) and tau, but how memory and emotional neural circuits are disrupted by AD pathology remains unclear. Here, we investigated the transcriptional vulnerability of memory and emotional circuits to concomitant Aβ and tau pathologies in transgenic mice expressing mutant human amyloid precursor protein (APP) and Tau (APP/Tau mice) in excitatory neurons. At 9 months, we detected common and region-specific transcriptional responses in the hippocampus and basolateral amygdala (BLA) of APP/Tau mice, including astrocytic, microglia and 63 AD-associated genes. These findings suggest that Aβ and tau pathologies disrupt region-specific gene expression programs underlying vulnerability of memory and emotional circuits to AD neuropathology.
Project description:Methylomic signatures of tau and beta amyloid in transgenic mouse models of Alzheimer’s disease neuropathology [HorvathMammalMethylChip40 Methylation Beadchip]
Project description:Alzheimer’s disease (AD) is characterized by memory loss associated with accumulation of amyloid-β (Aβ) and tau in the brain, but how memory-processing neural circuits are differentially affected by each pathology remains unclear. Here, we investigated the transcriptional vulnerability to single and concomitant Aβ and tau pathologies in 6-month-old transgenic mice expressing mutant human amyloid precursor protein (APP), Tau, or both (APP/Tau mice) in excitatory neurons. We identified differential and synergistic pathology-induced transcriptional responses in the hippocampus of AD transgenic mice. These findings support the idea that Aβ and tau pathologies exert synergistic effects to disrupt gene expression programs underlying vulnerability of memory neural circuits in AD.
Project description:Alzheimer’s disease (AD) is the most prevalent form of dementia and is characterized by abnormal extracellular aggregates of amyloid-b and intraneuronal hyperphosphorylated, tau tangles and neuropil threads. Microglia, the tissue-resident macrophages of the central nervous system (CNS), are important for CNS homeostasis and implicated in AD pathology. In amyloid mouse models, a phagocytic/activated microglia phenotype has been identified. How increasing levels of amyloid-b and tau pathology affect human microglia transcriptional profiles is unknown. Here, we performed snRNAseq on 482,472 nuclei from non-demented control brains and AD brains containing only amyloid-b plaques or both amyloid-b plaques and tau pathology. Within the microglia population, distinct expression profiles were identified of which two were AD pathology-associated. The phagocytic/activated AD1-microglia population abundance strongly correlated with tissue amyloid-b load and localized to amyloid-b plaques. The AD2-microglia abundance strongly correlated with tissue phospho-tau load and these microglia were more abundant in samples with over tau pathology. This full characterization of human disease associated microglia phenotypes provides new insights in the pathophysiological role of microglia in AD and offers new targets for microglia-state-specific therapeutic strategies.