Biology subjects

Felsky, D.

Publications and source records attributed to Felsky, D..

3 recordsLinked to original sources

bioRxiv2018

Neuropathological correlates and genetic architecture of microglial activation in elderly human brain

Microglia, the resident immune cells of the brain, have important roles in brain health. However, little is known about the regulation and consequences of microglial activation in the aging human brain. We assessed the effect of microglial activation in the aging human brain by calculating the proportion of activated microglia (PAM), based on morphologically defined stages of activation in four regions sampled postmortem from up to 225 elderly individuals. We found that cortical and not subcortical PAM measures were strongly associated with {beta}-amyloid, tau-related neuropathology, and rates of cognitive decline. Effect sizes for PAM measures are substantial, comparable to that of APOE {varepsilon}4, the strongest genetic risk factor for Alzheimers disease. Mediation modeling suggests that PAM accelerates accumulation of tau pathology leading to cognitive decline, supporting an upstream role for microglial activation in Alzheimers disease. Genome-wide analyses identified a common variant (rs2997325) influencing cortical PAM that also affected in vivo microglial activation measured by positron emission tomography using [11C]-PBR28 in an independent cohort. Finally, we identify overlaps of PAMs genetic architecture with those of Alzheimers disease, educational attainment, and several other traits.

genomics↗

bioRxiv2018

A multi-omic atlas of the human frontal cortex for aging and Alzheimer's disease research

We initiated the systematic profiling of the dorsolateral prefrontal cortex obtained from a subset of autopsied individuals enrolled in the Religious Orders Study (ROS) or the Rush Memory and Aging Project (MAP), which are jointly designed and belong to a very few prospective studies of aging and dementia with detailed, longitudinal cognitive phenotyping during life and a quantitative, structured neuropathologic examination after death for >3,322 subjects. Here, we outline the first generation of data including genome-wide genotypes (n=2,090), whole genome sequencing (n=1,179), DNA methylation (n=740), chromatin immunoprecipitation with sequencing using an anti-Histone 3 Lysine 9 acetylation (H3K9Ac) antibody (n=712), RNA sequencing (n=638), and miRNA profile (n=702). Generation of other omic data including ATACseq, proteomic and metabolomics profiles is ongoing. Thanks to its prospective design and recruitment of older, non-demented individuals, these data can be repurposed to investigate a large number of syndromic and quantitative neuroscience phenotypes. The many subjects that are cognitively non-impaired at death also offer insights into the biology of the human brain in older non-impaired individuals.

cell biology↗

bioRxiv2017

A cortical immune network map identifies a subset of human microglia involved in Tau pathology

Microglial dysfunction has been proposed as one of the many cellular mechanisms that can contribute to the development of Alzheimer's disease (AD). Here, using a transcriptional network map of the human frontal cortex, we identify five gene modules of co-expressed genes related to microglia and assess their role in the neuropathologic features of AD in 541 subjects from two cohort studies of brain aging. Two of these transcriptional programs - modules 113 and 114 - relate to the accumulation of {beta}-amyloid, while module 5 relates to tau pathology. These modules are also detectable in the human brain's epigenome, where we replicate these associations. In terms of tau, we propose that module 5, a marker of activated microglia, may lead to tau accumulation and subsequent cognitive decline. We validate our model further by showing that VASP, a representative module 5 gene, encodes a protein that is upregulated in activated microglia in AD.

neuroscience↗