bioRxiv preprint doi: https://doi.org/10.1101/2020.05.12.091819; this version posted May 14, 2020. The copyright holder for this preprint (which was not certified by peer review) is the author/funder, who has granted bioRxiv a license to display the preprint in perpetuity. It is made available under aCC-BY 4.0 International license.

Seizures are a druggable mechanistic link between TBI and subsequent tauopathy

Hadeel Alyenbaawi1,2,7, Richard Kanyo1,3, Laszlo F. Locskai1,3, Razieh Kamali-Jamil1,4, Michèle G. DuVal3, Qing Bai5, Holger Wille1,4, Edward A. Burton5,6, W. Ted Allison1,2,3*

1 Centre for Prions & Protein Folding Disease, University of Alberta, Edmonton AB, T6G 2M8, Canada 2 Department of Medical Genetics, University of Alberta, Edmonton AB, T6G 2H7, Canada 3 Department of Biological Sciences, University of Alberta, Edmonton AB, T6G 2E9, Canada 4 Department of Biochemistry, University of Alberta, Edmonton, AB, Canada 5 Department of , University of Pittsburgh, Pittsburgh, PA, USA 6 Geriatric Research, Education and Clinical Center, Pittsburgh VA Healthcare System, Pittsburgh, PA, USA. 7 Majmaah University, Majmaah,11952, Saudi Arabia

* Author for correspondence: [email protected], 780-492-4430

Running title: link TBI to subsequent Tauopathy

1 bioRxiv preprint doi: https://doi.org/10.1101/2020.05.12.091819; this version posted May 14, 2020. The copyright holder for this preprint (which was not certified by peer review) is the author/funder, who has granted bioRxiv a license to display the preprint in perpetuity. It is made available under aCC-BY 4.0 International license.

Graphical Abstract:

Highlights:

• Introduces first Traumatic Brain Injury (TBI) model in larval zebrafish, and its easy • TBI induces clinically relevant cell death, haemorrhage & post-traumatic seizures • Ca2+ imaging during TBI reveals spike in brain activity concomitant with seizures • Tau-GFP Biosensor allows repeated in vivo measures of prion-like tau aggregation • post-TBI, anticonvulsants stop tauopathies akin to Chronic Traumatic

2 bioRxiv preprint doi: https://doi.org/10.1101/2020.05.12.091819; this version posted May 14, 2020. The copyright holder for this preprint (which was not certified by peer review) is the author/funder, who has granted bioRxiv a license to display the preprint in perpetuity. It is made available under aCC-BY 4.0 International license.

Summary: 1 Traumatic brain injury (TBI) is a prominent risk factor for neurodegenerative diseases 2 and including chronic traumatic encephalopathy (CTE). TBI and CTE, like all 3 tauopathies, are characterized by accumulation of Tau into aggregates that 4 progressively spread to other brain regions in a prion-like manner. The mechanisms that 5 promote spreading and cellular uptake of tau seeds after TBI are not fully understood, in 6 part due to lack of tractable animal models. Here, we test the putative roles for excess 7 neuronal activity and dynamin-dependent endocytosis in promoting the in vivo spread of 8 tauopathy. We introduce ‘tauopathy reporter’ zebrafish expressing a genetically- 9 encoded fluorescent Tau biosensor that reliably reports accumulation of human tau 10 species when seeded via intra-ventricular brain injections. Subjecting zebrafish larvae to 11 a novel TBI paradigm produced various TBI symptoms including cell death, 12 hemorrhage, blood flow abnormalities, post–traumatic seizures, and Tau inclusions. 13 Bath application of anticonvulsant drugs rescued TBI-induced tauopathy and cell death; 14 these benefits were attributable to inhibition of post-traumatic seizures because co- 15 application of convulsants reversed these beneficial effects. However, one convulsant 16 drug, 4-Aminopyridine, unexpectedly abrogated TBI-induced tauopathy - this was due to 17 its