Marta Olah, United States of America
Columbia University Taub InstituteAuthor Of 1 Presentation
A MOLECULAR NETWORK FOR LIVING HUMAN MICROGLIAL SUBSETS IN AGING AND NEURODEGENERATIVE DISEASES
Abstract
Aims
The goal of the project involved empirically determining (1) the population structure of living human microglia, (2) the genetic architecture of microglial gene expression, and (3) the key regulator genes for microglial function.
Methods
We have purified live human microglia from autopsy tissue of 75 subjects - including 41 with a diagnosis of Alzheimer’s disease or MCI and 8 with a Parkinsonian syndrome - for single cell RNAseq. We sampled the neocortex (BA4, BA9, BA20/21), substantia nigra, hippocampus, and spinal cord. ARACNE-AP was used to map regulatory networks, and the VIPER algorithm was used to identify candidate regulators.
Results
We had 215,680 individual microglial transcriptomes after QC. We identified 13 discrete subtypes of microglia. There are two families of microglial subtypes, suggesting that there may be two primary paths of differentiation, which then lead to a diverse array of terminally differentiated states. To date, we have found one cluster, marked by high expression of CD74, to be reduced in frequency in AD, and have validated this result in histological data and brain single nucleus data. We have mapped cis-expression quantitative trait loci (cis-eQTL) in each subtype. Finally, we defined modules of co-expressed genes within and across the 13 clusters. We then used these modules to derive a network map of microglial subsets and their relation to different diseases and to identify candidate master regulators associated with each subtype.
Conclusions
We have generated an initial map of human microglial regulatory networks from 13 subsets of live microglia, highlighting key nodes that contribute to aging and neurodegeneration.