Gotz, J. | bioRxiv Science

bioRxiv2022

Genome-wide CRISPRi screening reveals regulators of Alzheimee's tau pathology shared between exosomal and vesicle-free tau seeds.

Aggregation of the microtubule-associated protein tau is a defining feature of Alzheimers disease and other tauopathies. Tau pathology is believed to be driven by both free tau aggregates and tau carried within exosomes, which propagate trans-synaptically and induce tau pathology in recipient neurons by a corrupting process of seeding. Here, we performed a genome-wide CRISPRi screen in tau biosensor cells and identified cellular regulators shared by both mechanisms of tau seeding. The top validated regulators are ANKLE2, BANF1, NUSAP1, EIF1AD, and VPS18, which work as factors that restrict tau aggregation initiated by both exosomal and vesicle-free tau seeds. Interestingly, ANKLE2 and BANF1 more robustly affected exosomal tau seeding than free aggregates. Lastly, validation studies revealed that several of the identified protein hits are downregulated in the brains of Alzheimers patients, suggesting that their decreased activity may be required for the emergence or progression of tau pathology in the human brain.

neuroscience↗

bioRxiv2021

Transcriptional signature in microglia isolated from an Alzheimers disease mouse model treated with scanning ultrasound

RationaleIntracranial scanning ultrasound combined with intravenously injected microbubbles (SUS+MB) has been shown to transiently open the blood-brain barrier and reduce amyloid-{beta} (A{beta}) pathology in the APP23 mouse model of Alzheimers disease (AD). This has been accomplished, at least in part, through the activation of microglial cells; however, their response to the SUS treatment is only incompletely understood. MethodsWild-type (WT) and APP23 mice were subjected to SUS+MB, using non-SUS+MB-treated mice as sham controls. After 48 hours, the APP23 mice were injected with methoxy-XO4 to label A{beta} aggregates, followed by microglial isolation into XO4+ and XO4- populations using flow cytometry. Both XO4+ and XO4- cells were subjected to RNA sequencing and their transcriptome was analyzed through a bioinformatics pipeline. ResultsThe transcriptomic analysis of the microglial cells revealed a clear segregation depending on genotype (AD model versus WT mice), as well as treatment (SUS+MB versus sham) and A{beta} internalization (XO4+ versus XO4- microglia). Differential gene expression analysis detected 278 genes that were significantly changed by SUS+MB in the XO4+ cells (248 up/30 down) and 242 in XO- cells (225 up/17 down). Not surprisingly given previous findings of increased phagocytosis of plaques following SUS+MB, the pathway analysis highlighted that the treatment induced an enrichment in genes related to the phagosome pathway in XO4+ microglia; however, when comparing SUS+MB to sham, the analysis revealed an enrichment in genes involved in the cell cycle in both the XO4+ and XO4- microglial population. ConclusionOur data provide a comprehensive analysis of microglia in an AD mouse model subjected to ultrasound treatment as a function of A{beta} internalization, one of the defining hallmarks of AD. Several differentially expressed genes are highlighted, pointing to an ultrasound-induced activation of cell cycle mechanisms in microglial cells isolated from APP23 mice treated with SUS+MB. Graphical abstract O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=86 SRC="FIGDIR/small/473590v1_ufig1.gif" ALT="Figure 1"> View larger version (22K): org.highwire.dtl.DTLVardef@9ae94org.highwire.dtl.DTLVardef@1a48d22org.highwire.dtl.DTLVardef@2dcb9dorg.highwire.dtl.DTLVardef@92dfb2_HPS_FORMAT_FIGEXP M_FIG C_FIG

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