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:Total of 56 microglia samples from postmortem brain tissue of four different brain regions, medial frontal gyrus (MFG), superior temporal gyrus (STG), subventricular zone (SVZ) and thalamus (THA), of 22 donors, encompassing 1 patient with schizophrenia, 13 patients with mood disorder pathology, and 8 control subjects, were isolated and assayed using a genome-wide methylation array to characterize the DNA methylation landscape of human microglia and the factors that contribute to variations in the microglia methylome
Project description:Gene expression changes determine functional differentiation during development and are associated with functional decline during aging. While developmental changes are tightly regulated, regulation of aging changes is not well established. To assess the regulatory basis of age-related changes and investigate the mechanism of regulatory transition between development and aging, we measured mRNA and microRNA expression patterns in brains (superior frontal gyrus) of humans and rhesus macaques over the entire speciesâ lifespan. We find that in both species, developmental and aging changes overlap in the course of lifetime with many changes found at the late age initiating in early childhood. Human post-mortem brain samples from the superior frontal gyrus region of the prefrontal cortex were collected. The age ranges of the indibiual in human covered its whole life span fom newborn to death. RNA extracted from the dissected tissue was hybridized to Affymetrix® Human Gene 1.0 ST arrays. Rhesus macaque post-mortem brain samples from the superior frontal gyrus region of the prefrontal cortex were collected. The age ranges of the indibiual in rhesus macaque covered the whole life span fom newborn to death. RNA extracted from the dissected tissue was hybridized to Affymetrix® Human Gene 1.0 ST arrays.
Project description:In development, timing is of the utmost importance, and the timing of various developmental processes are often changed during evolution. During human evolution sexual maturation has been delayed relative to other primates and this may have played a critical role for both the increase of human brain size and the rise of human-specific cognitive traits . We measured the timing of gene expression changes in the superior frontal gyrus region of the brains of humans, chimpanzees, and rhesus macaques throughout postnatal development. Keywords: Age series Human, chimpanzee and rhesus macaque post-mortem brain samples from the superior frontal gyrus region of the prefrontal cortex were collected. The age ranges of the individuals in all three species covered the respective species' postnatal maturation period from infancy to adulthood. RNA extracted from the dissected tissue was hybridized to Affymetrix® Human Gene 1.0 ST arrays.
Project description:Layer II stellate neurons (entorhinal cortex) and layer III cortical neurons (hippocampus CA1, middle temporal gyrus, posterior cingulate, superior frontal gyrus, primary visual cortex) were gene expression profiled. Brain regions are from non-demented individuals with intermediate Alzheimer's disease neuropathologies Keywords: neuronal gene expression profiling
Project description:The temporal lobe is the cerebral cortex with critical function. The superior and middle gyrus of temporal lobe have been well studied, however, present perceptions on inferior temporal gyrus remains limited. The understanding of age-related protein profile change in human inferior temporal gyrus has not yet been well established. This 3-plex TMT labeled proteomic study is performed based on the human brain bank at the Chinese Academy of Medical Sciences & Peking Union Medical College. Age distribution of the donors ranges from 22 to 90 years old, and were assigned to three age groups: 20-50, 50-70, and 70-90 years of death age. In this ageing cohort, no neurodegenerative disorders or major stroke events were identified via standard neuropathological classification. Proteomics and bioinformatics strategies were applied to identify the perturbations of protein expression and associated pathways. Among all the ITG samples, 3113 proteins were isolated, with 37 proteins upregulated and 21 proteins downregulated.
Project description:Alzheimer's disease is a progressive neurodegenerative disorder that is hypothesized to involve epigenetic dysfunction. We undertook an epigenome-wide association study across three independent brain tissue cohorts (total n = 999) to identify differential DNA methylation associated with neuropathology in the superior temporal gyrus and prefrontal cortex. We present robust evidence for elevated DNA methylation associated with AD neuropathology across an extended region spanning the HOXA gene cluster on chromosome 7. Prefrontal cortex and superior temporal gyrus tissue from 147 individuals with varying levels of AD pathology. DNA modifications for these samples were quantified using the Illumina Infinium Human 450K Methylation Array.
Project description:Recent work has identified roles for environmental, genetic and epigenetic factors in AD risk. Motivated by suspected roles for epigenetic modifications in AD, we performed a genome-wide screen of DNA methylation using the Illumina Infinium HumanMethylation450 array platform on bulk tissue samples from the superior temporal gyrus (STG) of AD cases and non-demented controls. We paired a sliding window approach with linear models that account for age, gender, ethnicity, and estimated cellular proportions (neuronal vs. glial), to characterize AD-associated differentially methylated regions (DMRs). Whole DNA was extracted from STG tissue dissections collected from deceased individuals with and without Alzheimers Disease. DNA was bisulfite converted and global DNA methylation levels were assessed using Illumina Infinium HumanMethylation450 BeadChip.
Project description:Layer II stellate neurons (entorhinal cortex) and layer III cortical neurons (hippocampus CA1, middle temporal gyrus, posterior cingulate, superior frontal gyrus, primary visual cortex) were gene expression profiled. Brain regions are from individuals who had been diagnosed with mild cognitive impairment. Experiment Overall Design: ~500 neurons were selected from each of 6 brain regions. Total RNA was isolated from each batch of neurons, double round amplified, and hybridized to Affymetrix Human Genome U133 Plus 2.0 arrays.
Project description:Circular RNAs (circRNAs) represent a class of endogenous, non-coding RNAs that are formed when exons back splice to each other and that are both highly conserved and pervasively expressed in the mammalian brain. The goal of this study was thus to systematically identify and characterize circRNA expression and as well as to evaluate the predicted impact on regulatory networks in five functionally distinct cortical regions of healthy aged human brain - cerebellum (BC), inferior parietal lobe (IPL), middle temporal gyrus (MTG), occipital cortex (OC) and superior frontal gyrus (SGF).