title: Striatal and nigral pathology in a lentiviral rat model of Machado-Joseph disease.
abstract: Machado-Joseph disease (MJD) is a fatal, dominant neurodegenerative disorder. MJD results from polyglutamine repeat expansion in the MJD-1 gene, conferring a toxic gain of function to the ataxin-3 protein. In this study, we aimed at overexpressing ataxin-3 in the rat brain using lentiviral vectors (LV), to generate an in vivo MJD genetic model and, to study the disorder in defined brain regions: substantia nigra, an area affected in MJD, cortex and striatum, regions not previously reported to be affected in MJD. LV encoding mutant or wild-type human ataxin-3 was injected in the brain of adult rats and the animals were tested for behavioral deficits and neuropathological abnormalities. Striatal pathology was confirmed in transgenic mice and human tissue. In substantia nigra, unilateral overexpression of mutant ataxin-3 led to: apomorphine-induced turning behavior; formation of ubiquitinated ataxin-3 aggregates; alpha-synuclein immunoreactivity; and loss of dopaminergic markers (TH and VMAT2). No neuropathological changes were observed upon wild-type ataxin-3 overexpression. Mutant ataxin-3 expression in striatum and cortex, resulted in accumulation of misfolded ataxin-3, and within striatum, loss of neuronal markers. Striatal pathology was confirmed by observation in MJD transgenic mice of ataxin-3 aggregates and substantial reduction of DARPP-32 immunoreactivity and, in human striata, by ataxin-3 inclusions, immunoreactive for ubiquitin and alpha-synuclein. This study demonstrates the use of LV encoding mutant ataxin-3 to produce a model of MJD and brings evidence of striatal pathology, suggesting that this region may contribute to dystonia and chorea observed in some MJD patients and may represent a target for therapies.
authors.affiliation: Center for Neurosciences and Cell Biology, University of Coimbra, Coimbra, Portugal.
authors.forename: Sandro
authors.initials: S
authors.lastname: Alves
authors.forename: Etienne
authors.initials: E
authors.lastname: Régulier
authors.forename: Isabel
authors.initials: I
authors.lastname: Nascimento-Ferreira
authors.forename: Raymonde
authors.initials: R
authors.lastname: Hassig
authors.forename: Noelle
authors.initials: N
authors.lastname: Dufour
authors.forename: Arnulf
authors.initials: A
authors.lastname: Koeppen
authors.forename: Ana Luísa
authors.initials: AL
authors.lastname: Carvalho
authors.forename: Sérgio
authors.initials: S
authors.lastname: Simões
authors.forename: Maria C Pedroso
authors.initials: MC
authors.lastname: de Lima
authors.forename: Emmanuel
authors.initials: E
authors.lastname: Brouillet
authors.forename: Veronica Colomer
authors.initials: VC
authors.lastname: Gould
authors.forename: Nicole
authors.initials: N
authors.lastname: Déglon
authors.forename: Luís Pereira
authors.initials: LP
authors.lastname: de Almeida
mesh_terms: D000368:Aged; D000818:Animals; D000067699:Ataxin-3; D001522:Behavior, Animal; D002460:Cell Line; D004195:Disease Models, Animal; D005260:Female; D015870:Gene Expression; D015316:Genetic Therapy; D005822:Genetic Vectors / Q000235:genetics; D006801:Humans; D016086:Lentivirus / Q000235:genetics* / Q000378:metabolism; D017827:Machado-Joseph Disease / Q000378:metabolism / Q000473:pathology / Q000503:physiopathology* / Q000628:therapy*; D008297:Male; D051379:Mice; D008822:Mice, Transgenic; D008875:Middle Aged; D009419:Nerve Tissue Proteins / Q000235:genetics / Q000378:metabolism* / Q000494:pharmacology / Q000627:therapeutic use; D009687:Nuclear Proteins / Q000235:genetics / Q000378:metabolism* / Q000494:pharmacology / Q000627:therapeutic use; D051381:Rats; D017208:Rats, Wistar; D012097:Repressor Proteins / Q000235:genetics / Q000378:metabolism* / Q000494:pharmacology / Q000627:therapeutic use; D013378:Substantia Nigra / Q000378:metabolism / Q000473:pathology / Q000503:physiopathology*; D014446:Tyrosine 3-Monooxygenase / Q000378:metabolism; D050493:Vesicular Monoamine Transport Proteins / Q000378:metabolism; D014793:Visual Cortex / Q000378:metabolism / Q000473:pathology / Q000503:physiopathology*
chemical_list: D009419:Nerve Tissue Proteins; D009687:Nuclear Proteins; D012097:Repressor Proteins; D050493:Vesicular Monoamine Transport Proteins; D014446:Tyrosine 3-Monooxygenase; C092341:ATXN3 protein, human; D000067699:Ataxin-3