title: Behavioral abnormalities precede neuropathological markers in rats transgenic for Huntington's disease.
abstract: Huntington's disease (HD) is caused by an expanded CAG repeat leading to the synthesis of an aberrant protein and to the formation of polyglutamine (polyQ)-containing inclusions and aggregates. Limited information is available concerning the association of neuropathological markers with the development of behavioral markers in HD. Using a previously generated transgenic rat model of HD (tgHD rat), we performed association studies on the time-course of behavioral symptoms (motor function, learning, anxiety) and the appearance of striatal atrophy, 1C2 immunopositive aggregates and polyQ recruitment sites, a precursor to these aggregates. At the age of 1 month, tgHD rats exhibited reduced anxiety and improved motor performance, while at 6 months motor impairments and at 9 months cognitive decline occurred. In contrast, polyQ recruitment sites appeared at around 6-9 months of age, indicating that HD-like behavioral markers preceded the appearance of currently detectable neuropathological markers. Interestingly, numerous punctate sites containing polyQ aggregates were also seen in areas receiving afferents from the densely recruiting regions suggesting either transport of recruitment-competent aggregates to terminal projections where initially 1C2 positive aggregates were formed or different internal properties of neurons in different regions. Furthermore, striatal atrophy was observed at the age of 12 months. Taken together, our findings support the hypothesis of a dynamic process leading to region- and age-specific polyQ recruitment and aggregation. The dissociation of onset between behavioral and neuropathological markers is suggestive of as yet undetected processes, which contribute to the early phenotype of these HD transgenic rats.
authors.affiliation: Department of Functional and Applied Anatomy, Medical School of Hannover, Germany.
authors.forename: Huu Phuc
authors.initials: HP
authors.lastname: Nguyen
authors.forename: Philipp
authors.initials: P
authors.lastname: Kobbe
authors.forename: Henning
authors.initials: H
authors.lastname: Rahne
authors.forename: Till
authors.initials: T
authors.lastname: Wörpel
authors.forename: Burkard
authors.initials: B
authors.lastname: Jäger
authors.forename: Michael
authors.initials: M
authors.lastname: Stephan
authors.forename: Reinhard
authors.initials: R
authors.lastname: Pabst
authors.forename: Carsten
authors.initials: C
authors.lastname: Holzmann
authors.forename: Olaf
authors.initials: O
authors.lastname: Riess
authors.forename: Hubert
authors.initials: H
authors.lastname: Korr
authors.forename: Orsolya
authors.initials: O
authors.lastname: Kántor
authors.forename: Elisabeth
authors.initials: E
authors.lastname: Petrasch-Parwez
authors.forename: Ronald
authors.initials: R
authors.lastname: Wetzel
authors.forename: Alexander
authors.initials: A
authors.lastname: Osmand
authors.forename: Stephan
authors.initials: S
authors.lastname: von Hörsten
mesh_terms: D000375:Aging; D000818:Animals; D030801:Animals, Genetically Modified; D001007:Anxiety; D001362:Avoidance Learning; D001522:Behavior, Animal; D001921:Brain / Q000378:metabolism / Q000473:pathology*; D003342:Corpus Striatum / Q000378:metabolism / Q000473:pathology; D006816:Huntington Disease / Q000473:pathology* / Q000503:physiopathology / Q000523:psychology*; D008297:Male; D018782:Maze Learning; D009043:Motor Activity; D011099:Polyglutamic Acid / Q000378:metabolism; D011597:Psychomotor Performance; D051381:Rats; D017207:Rats, Sprague-Dawley
chemical_list: D011099:Polyglutamic Acid