
==== Front
bioRxiv
BIORXIV
bioRxiv
2692-8205
Cold Spring Harbor Laboratory

10.1101/2024.08.19.608477
preprint
1
Article
Molecular Visualization of Neuronal TDP43 Pathology In Situ
Erwin Amanda L.
Chang Matthew L.
Fernandez Martin G.
Attili Durga
Russ Jennifer E.
Sutanto Renaldo
Pinarbasi Emile S.
Bekier Michael
Brant Tyler S.
Hahn Terry
Dykstra Megan
Thomas Dafydd
Li Xingli
Baldridge Ryan D. http://orcid.org/0000-0001-7158-7812

Tank Elizabeth M. H.
Barmada Sami J. http://orcid.org/0000-0002-9604-968X

Mosalaganti Shyamal http://orcid.org/0000-0002-5934-687X

19 8 2024
2024.08.19.608477https://creativecommons.org/licenses/by-nc-nd/4.0/ This work is licensed under a Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International License, which allows reusers to copy and distribute the material in any medium or format in unadapted form only, for noncommercial purposes only, and only so long as attribution is given to the creator.
http://biorxiv.org/lookup/doi/10.1101/2024.08.19.608477
nihpp-2024.08.19.608477.pdf
Abstract

Nuclear exclusion and cytoplasmic accumulation of the RNA-binding protein TDP43 are characteristic of amyotrophic lateral sclerosis (ALS) and frontotemporal lobar degeneration (FTLD). Despite this, the origin and ultrastructure of cytosolic TDP43 deposits remain unknown. Accumulating evidence suggests that abnormal RNA homeostasis can drive pathological TDP43 mislocalization, enhancing RNA misprocessing due to loss of nuclear TDP43 and engendering a cycle that ends in cell death. Here, we show that adding small monovalent oligonucleotides successfully recapitulates pathological TDP43 mislocalization and aggregation in iPSC-derived neurons (iNeurons). By employing a multimodal in situ cryo-correlative light and electron microscopy pipeline, we examine how RNA influences the localization and aggregation of TDP43 in near-native conditions. We find that mislocalized TDP43 forms ordered fibrils within lysosomes and autophagosomes in iNeurons as well as in patient tissue, and provide the first high-resolution snapshots of TDP43 aggregates in situ . In so doing, we provide a cellular model for studying initial pathogenic events underlying ALS, FTLD, and related TDP43-proteinopathies.
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pmc
