title: α-Synuclein expression in rat substantia nigra suppresses phospholipase D2 toxicity and nigral neurodegeneration.
abstract: We present genetic evidence that an in vivo role of α-synuclein (α-syn) is to inhibit phospholipase D2 (PLD2), an enzyme that is believed to participate in vesicle trafficking, membrane signaling, and both endo- and exocytosis. Overexpression of PLD2 in rat substantia nigra pars compacta (SNc) caused severe neurodegeneration of dopamine (DA) neurons, loss of striatal DA, and an associated ipsilateral amphetamine-induced rotational asymmetry. Coexpression of human wild type α-syn suppressed PLD2 neurodegeneration, DA loss, and amphetamine-induced rotational asymmetry. However, an α-syn mutant defective for inhibition of PLD2 in vitro also failed to inhibit PLD toxicity in vivo. Further, reduction of PLD2 activity in SNc, either by siRNA knockdown of PLD2 or overexpression of α-syn, both produced an unusual contralateral amphetamine-induced rotational asymmetry, opposite to that seen with overexpression of PLD2, suggesting that PLD2 and α-syn were both involved in DA release or reuptake. Finally, α-syn coimmunoprecipitated with PLD2 from extracts prepared from striatal tissues. Taken together, our data demonstrate that α-syn is an inhibitor of PLD2 in vivo, and confirm earlier reports that α-syn inhibits PLD2 in vitro. Our data also demonstrate that it is possible to use viral-mediated gene transfer to study gene interactions in vivo.
authors.affiliation: Department of Molecular Genetics and Microbiology, College of Medicine, University of Florida, Gainesville, Florida, USA. olegor@ufl.edu
authors.forename: Oleg S
authors.initials: OS
authors.lastname: Gorbatyuk
authors.forename: Shoudong
authors.initials: S
authors.lastname: Li
authors.forename: Frederic Nha
authors.initials: FN
authors.lastname: Nguyen
authors.forename: Fredric P
authors.initials: FP
authors.lastname: Manfredsson
authors.forename: Galina
authors.initials: G
authors.lastname: Kondrikova
authors.forename: Layla F
authors.initials: LF
authors.lastname: Sullivan
authors.forename: Craig
authors.initials: C
authors.lastname: Meyers
authors.forename: Weijun
authors.initials: W
authors.lastname: Chen
authors.forename: Ronald J
authors.initials: RJ
authors.lastname: Mandel
authors.forename: Nicholas
authors.initials: N
authors.lastname: Muzyczka
mesh_terms: D000818:Animals; D000229:Dependovirus / Q000235:genetics; D004298:Dopamine / Q000378:metabolism; D005822:Genetic Vectors / Q000235:genetics; D015151:Immunoblotting; D007150:Immunohistochemistry; D018613:Microscopy, Confocal; D009410:Nerve Degeneration / Q000235:genetics / Q000378:metabolism*; D010739:Phospholipase D / Q000235:genetics / Q000378:metabolism*; D010957:Plasmids / Q000235:genetics; D051381:Rats; D020133:Reverse Transcriptase Polymerase Chain Reaction; D013378:Substantia Nigra / Q000378:metabolism* / Q000473:pathology*; D051844:alpha-Synuclein / Q000235:genetics / Q000378:metabolism*
chemical_list: D051844:alpha-Synuclein; C105606:phospholipase D2; D010739:Phospholipase D; D004298:Dopamine