Paper

Compromised function of the ESCRT pathway promotes endolysosomal escape of tau seeds and propagation of tau aggregation

Chen, John J, Hein, Marco Y, Southworth, Daniel R, Leonetti, Manuel D, Tse, Eric, Gestwicki, Jason E, Nelson, Maxine, Nathaniel, Diane L, Kampmann, Martin, Grinberg, Lea T, Hong, Jason Y, Tian, Ruilin, Raghavan, Preethi, See, Stephanie K, Mok, Sue-Ann

2019

Overview

Intercellular propagation of protein aggregation is emerging as a key mechanism in the progression of several neurodegenerative diseases, including Alzheimer's Disease and frontotemporal dementia. However, we lack a systematic understanding of the cellular pathways controlling prion-like propagation. To uncover such pathways, we performed CRISPR interference (CRISPRi) screens in a human cell-based model of propagation of tau aggregation. Our screens uncovered that knockdown of several components of the ESCRT machinery, including CHMP6, or CHMP2A in combination with CHMP2B (a gene linked to familial frontotemporal dementia), promote propagation of tau aggregation. We found that knockdown of these genes caused damage to endolysosomal membranes, consistent with a role for the ESCRT pathway in endolysosomal membrane repair. Leakiness of the endolysosomal compartment significantly enhanced prion-like propagation of tau aggregation, likely by making tau seeds more available to pools of cytoplasmic tau. Together, these findings suggest that endolysosomal escape is a critical step in tau propagation. Footnotes * In additional experiments, we: - Showed that several ESCRT proteins, including a member of the ESCRT-I complex, had similar phenotypes to CHMP6 (new Fig. 4F), and we updated the title and the abstract of the manuscript accordingly. - Conducted longitudinal imaging for 48 hours to quantify co-localization of labeled tau fibrils with the endolysosomal compartment (new Fig. 4B,C and new Supplementary Movies 4,5), and found consistently lower co-localization in CHMP-6 knockdown cells. - Showed that tau fibrils by themselves did not cause endolysosomal damage in our cell-based model (new Fig. 4D,E).

• Publisher: Cold Spring Harbor Laboratory Press,Cold Spring Harbor Laboratory
• Subject: Alzheimer's disease / Cell Biology / CRISPR / Dementia / Dementia disorders / Frontotemporal dementia / Neurodegenerative diseases / Propagation / Protein interaction / Seeds / Tau protein