A single-nuclei RNA sequencing study of Mendelian and sporadic AD in the human brain.

TitleA single-nuclei RNA sequencing study of Mendelian and sporadic AD in the human brain.
Publication TypeJournal Article
Year of Publication2019
AuthorsDel-Aguila JL, Li Z, Dube U, Mihindukulasuriya KA, Budde JP, Fernández MVictoria, Ibañez L, Bradley J, Wang F, Bergmann K, Davenport R, Morris JC, Holtzman DM, Perrin RJ, Benitez BA, Dougherty J, Cruchaga C, Harari O
JournalAlzheimers Res Ther
Date Published2019 08 09
KeywordsAged, 80 and over, Alzheimer Disease, Atlases as Topic, Female, Gene Expression, Humans, Male, Microglia, Mutation, Neurons, Parietal Lobe, Presenilin-1, Sequence Analysis, RNA

BACKGROUND: Alzheimer's disease (AD) is the most common form of dementia. This neurodegenerative disorder is associated with neuronal death and gliosis heavily impacting the cerebral cortex. AD has a substantial but heterogeneous genetic component, presenting both Mendelian and complex genetic architectures. Using bulk RNA-seq from the parietal lobes and deconvolution methods, we previously reported that brains exhibiting different AD genetic architecture exhibit different cellular proportions. Here, we sought to directly investigate AD brain changes in cell proportion and gene expression using single-cell resolution.

METHODS: We generated unsorted single-nuclei RNA sequencing data from brain tissue. We leveraged the tissue donated from a carrier of a Mendelian genetic mutation, PSEN1 p.A79V, and two family members who suffer from sporadic AD, but do not carry any autosomal mutations. We evaluated alternative alignment approaches to maximize the titer of reads, genes, and cells with high quality. In addition, we employed distinct clustering strategies to determine the best approach to identify cell clusters that reveal neuronal and glial cell types and avoid artifacts such as sample and batch effects. We propose an approach to cluster cells that reduces biases and enable further analyses.

RESULTS: We identified distinct types of neurons, both excitatory and inhibitory, and glial cells, including astrocytes, oligodendrocytes, and microglia, among others. In particular, we identified a reduced proportion of excitatory neurons in the Mendelian mutation carrier, but a similar distribution of inhibitory neurons. Furthermore, we investigated whether single-nuclei RNA-seq from the human brains recapitulate the expression profile of disease-associated microglia (DAM) discovered in mouse models. We also determined that when analyzing human single-nuclei data, it is critical to control for biases introduced by donor-specific expression profiles.

CONCLUSION: We propose a collection of best practices to generate a highly detailed molecular cell atlas of highly informative frozen tissue stored in brain banks. Importantly, we have developed a new web application to make this unique single-nuclei molecular atlas publicly available.

Alternate JournalAlzheimers Res Ther
PubMed ID31399126
PubMed Central IDPMC6689177
Grant ListR01 AG057777 / AG / NIA NIH HHS / United States
P01 AG026276 / AG / NIA NIH HHS / United States
R01AG057777 / GF / NIH HHS / United States
P01 AG003991 / AG / NIA NIH HHS / United States
P50 AG005681 / AG / NIA NIH HHS / United States