title: Sodium selenate, a protein phosphatase 2A activator, mitigates hyperphosphorylated tau and improves repeated mild traumatic brain injury outcomes.
abstract: Mild traumatic brain injuries may result in cumulative brain damage and neurodegenerative disease. To date, there is no pharmaceutical intervention known to prevent these consequences. Hyperphosphorylated tau has been associated in this process, and protein phosphatase 2A 55 kDa regulatory B subunit (PP2A/PR55) - the major tau phosphatase - is decreased after a brain insult. Sodium selenate up-regulates PP2A/PR55 and dephosphorylates tau, and may hold promise as a treatment in the mild brain injury setting. Here we investigated sodium selenate treatment in rats given repeated mild traumatic brain injuries. Rats were given three mild fluid percussion injuries or three sham-injuries, and treated with sodium selenate (1 mg/kg/day) or saline-vehicle for three months before undergoing behavioral testing, MRI, and post-mortem analysis of brain tissue. Repeated mild traumatic brain injuries increased the phosphorylation of tau and decreased PP2A/PR55, whilst inducing brain atrophy and cognitive and sensorimotor deficits. Sodium selenate treatment increased PP2A/PR55, and decreased tau phosphorylation, brain damage, and cognitive and motor impairments in rats given repeated mild traumatic brain injuries. Our findings implicate PP2A/PR55 and tau as important mechanisms in the pathophysiological aftermath of repeated mild brain traumas, and support sodium selenate as a novel and translatable treatment for these common injuries.
authors.affiliation: Department of Medicine, The Royal Melbourne Hospital, The University of Melbourne, Parkville, VIC, 3050, Australia.
authors.forename: Xin L
authors.initials: XL
authors.lastname: Tan
authors.affiliation: Anatomy and Neuroscience, The University of Melbourne, Parkville, VIC, 3010, Australia; The Florey Institute of Neuroscience and Mental Health, Parkville, VIC, 3052, Australia.
authors.forename: David K
authors.initials: DK
authors.lastname: Wright
authors.affiliation: Department of Medicine, The Royal Melbourne Hospital, The University of Melbourne, Parkville, VIC, 3050, Australia.
authors.forename: Shijie
authors.initials: S
authors.lastname: Liu
authors.affiliation: Department of Surgery, The Royal Melbourne Hospital, The University of Melbourne, Parkville, VIC, 3050, Australia.
authors.forename: Christopher
authors.initials: C
authors.lastname: Hovens
authors.affiliation: Department of Medicine, The Royal Melbourne Hospital, The University of Melbourne, Parkville, VIC, 3050, Australia.
authors.forename: Terence J
authors.initials: TJ
authors.lastname: O'Brien
authors.affiliation: Department of Medicine, The Royal Melbourne Hospital, The University of Melbourne, Parkville, VIC, 3050, Australia. Electronic address: sshultz@unimelb.edu.au.
authors.forename: Sandy R
authors.initials: SR
authors.lastname: Shultz
mesh_terms: D000818:Animals; D001924:Brain Concussion / Q000188:drug therapy* / Q000378:metabolism*; D004789:Enzyme Activation / Q000187:drug effects / Q000502:physiology; D008297:Male; D010766:Phosphorylation / Q000187:drug effects / Q000502:physiology; D054648:Protein Phosphatase 2 / Q000378:metabolism*; D051381:Rats; D020318:Rats, Long-Evans; D064586:Selenic Acid / Q000494:pharmacology / Q000627:therapeutic use*; D016875:tau Proteins / Q000037:antagonists & inhibitors / Q000378:metabolism*
chemical_list: D016875:tau Proteins; D054648:Protein Phosphatase 2; D064586:Selenic Acid
keywords: MRI; chronic traumatic encephalopathy; concussion; diffusion tensor imaging; tauopathy; traumatic brain injury