title: Progressive Motor Deficit is Mediated by the Denervation of Neuromuscular Junctions and Axonal Degeneration in Transgenic Mice Expressing Mutant (P301S) Tau Protein.
abstract: Tauopathies include a variety of neurodegenerative diseases associated with the pathological aggregation of hyperphosphorylated tau, resulting in progressive cognitive decline and motor impairment. The underlying mechanism for motor deficits related to tauopathy is not yet fully understood. Here, we use a novel transgenic tau mouse line, Tau 58/4, with enhanced neuron-specific expression of P301S mutant tau to investigate the motor abnormalities in association with the peripheral nervous system. Using stationary beam, gait, and rotarod tests, motor deficits were found in Tau 58/4 mice already 3 months after birth, which deteriorated during aging. Hyperphosphorylated tau was detected in the cell bodies and axons of motor neurons. At the age of 9 and 12 months, significant denervation of the neuromuscular junction in the extensor digitorum longus muscle was observed in Tau 58/4 mice, compared to wild-type mice. Muscle hypotrophy was observed in Tau 58/4 mice at 9 and 12 months. Using electron microscopy, we observed ultrastructural changes in the sciatic nerve of 12-month-old Tau 58/4 mice indicative of the loss of large axonal fibers and hypomyelination (assessed by g-ratio). We conclude that the accumulated hyperphosphorylated tau in the axon terminals may induce dying-back axonal degeneration, myelin abnormalities, neuromuscular junction denervation, and muscular atrophy, which may be the mechanisms responsible for the deterioration of the motor function in Tau 58/4 mice. Tau 58/4 mice represent an interesting neuromuscular degeneration model, and the pathological mechanisms might be responsible for motor signs observed in some human tauopathies.
authors.affiliation: Department of Neuroscience, Section Medical Physiology, University Medical Center Groningen, University of Groningen, Groningen, The Netherlands.|Department of Medical Ultrasound, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China.
authors.forename: Zhuoran
authors.initials: Z
authors.lastname: Yin
authors.affiliation: Laboratory of Neurochemistry and Behavior, Institute Born-Bunge, University of Antwerp, Antwerp, Belgium.
authors.forename: Femke
authors.initials: F
authors.lastname: Valkenburg
authors.affiliation: Department of Neurobiology, Groningen Institute for Evolutionary Life Science, University of Groningen, Groningen, The Netherlands.
authors.forename: Betty E
authors.initials: BE
authors.lastname: Hornix
authors.affiliation: Department of Neuroscience, Section Medical Physiology, University Medical Center Groningen, University of Groningen, Groningen, The Netherlands.
authors.forename: Ietje
authors.initials: I
authors.lastname: Mantingh-Otter
authors.affiliation: Department of Cell Biology, University Medical Center Groningen, University of Groningen, Groningen, The Netherlands.|Department of Preventive Veterinary Medicine, College of Veterinary Medicine, Northeast Agricultural University, Harbin, China.
authors.forename: Xingdong
authors.initials: X
authors.lastname: Zhou
authors.affiliation: Department of Cell Biology, University Medical Center Groningen, University of Groningen, Groningen, The Netherlands.
authors.forename: Muriel
authors.initials: M
authors.lastname: Mari
authors.affiliation: Department of Cell Biology, University Medical Center Groningen, University of Groningen, Groningen, The Netherlands.
authors.forename: Fulvio
authors.initials: F
authors.lastname: Reggiori
authors.affiliation: Laboratory of Neurochemistry and Behavior, Institute Born-Bunge, University of Antwerp, Antwerp, Belgium.|Department of Neurology and Alzheimer Research Center, University Medical Center Groningen, University of Groningen, Groningen, The Netherlands.
authors.forename: Debby
authors.initials: D
authors.lastname: Van Dam
authors.affiliation: Department of Neuroscience, Section Medical Physiology, University Medical Center Groningen, University of Groningen, Groningen, The Netherlands.
authors.forename: Bart J L
authors.initials: BJL
authors.lastname: Eggen
authors.affiliation: Laboratory of Neurochemistry and Behavior, Institute Born-Bunge, University of Antwerp, Antwerp, Belgium.|Department of Neurology and Alzheimer Research Center, University Medical Center Groningen, University of Groningen, Groningen, The Netherlands.|Biobank, Institute Born-Bunge, Antwerp, Belgium.
authors.forename: Peter P
authors.initials: PP
authors.lastname: De Deyn
authors.affiliation: Department of Neuroscience, Section Medical Physiology, University Medical Center Groningen, University of Groningen, Groningen, The Netherlands.
authors.forename: Erik
authors.initials: E
authors.lastname: Boddeke
mesh_terms: D000367:Age Factors; D000818:Animals; D001369:Axons / Q000473:pathology / Q000648:ultrastructure; D004195:Disease Models, Animal; D005684:Gait / Q000235:genetics; D006801:Humans; D051379:Mice; D008822:Mice, Transgenic; D008854:Microscopy, Electron; D000068079:Motor Disorders / Q000209:etiology*; D009046:Motor Neurons / Q000378:metabolism / Q000473:pathology; D053580:Muscle Strength / Q000235:genetics; D009154:Mutation / Q000235:genetics*; D009186:Myelin Sheath / Q000473:pathology / Q000648:ultrastructure; D009410:Nerve Degeneration / Q000150:complications* / Q000235:genetics* / Q000473:pathology; D020511:Neuromuscular Junction Diseases / Q000209:etiology*; D011597:Psychomotor Performance / Q000502:physiology; D045442:Rotarod Performance Test; D018709:Statistics, Nonparametric; D016875:tau Proteins / Q000235:genetics* / Q000378:metabolism
chemical_list: D016875:tau Proteins
keywords: Alzheimer’s disease; axonal degeneration; motor dysfunction; neuromuscular junction denervation; tauopathy