title: Non-motor parkinsonian pathology in aging A53T α-synuclein mice is associated with progressive synucleinopathy and altered enzymatic function.
abstract: Aging, the main risk factor for Parkinson's disease (PD), is associated with increased α-synuclein levels in substantia nigra pars compacta (SNc). Excess α-synuclein spurs Lewy-like pathology and dysregulates the activity of protein phosphatase 2A (PP2A). PP2A dephosphorylates many neuroproteins, including the catecholamine rate-limiting enzyme, tyrosine hydroxylase (TH). A loss of nigral dopaminergic neurons induces PD movement problems, but before those abnormalities occur, behaviors such as olfactory loss, anxiety, and constipation often manifest. Identifying mouse models with early PD behavioral changes could provide a model in which to test emerging therapeutic compounds. To this end, we evaluated mice expressing A53T mutant human (A53T) α-synuclein for behavior and α-synuclein pathology in olfactory bulb, adrenal gland, and gut. Aging A53T mice exhibited olfactory loss and anxiety that paralleled olfactory and adrenal α-synuclein aggregation. PP2A activity was also diminished in olfactory and adrenal tissues harboring insoluble α-synuclein. Low adrenal PP2A activity co-occurred with TH hyperactivity, making this the first study to link adrenal synucleinopathy to anxiety and catecholamine dysregulation. Aggregated A53T α-synuclein recombinant protein also had impaired stimulatory effects on soluble recombinant PP2A. Collectively, the data identify an excellent model in which to screen compounds for their ability to block the spread of α-synuclein pathology associated with pre-motor stages of PD.
authors.affiliation: Department of Neurology, Pittsburgh Institute for Neurodegenerative Diseases, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania, USA.
authors.forename: Kaitlin F
authors.initials: KF
authors.lastname: Farrell
authors.forename: Sesha
authors.initials: S
authors.lastname: Krishnamachari
authors.forename: Ernesto
authors.initials: E
authors.lastname: Villanueva
authors.forename: Haiyan
authors.initials: H
authors.lastname: Lou
authors.forename: Tshianda N M
authors.initials: TN
authors.lastname: Alerte
authors.forename: Eloise
authors.initials: E
authors.lastname: Peet
authors.forename: Robert E
authors.initials: RE
authors.lastname: Drolet
authors.forename: Ruth G
authors.initials: RG
authors.lastname: Perez
mesh_terms: D000311:Adrenal Glands / Q000201:enzymology / Q000378:metabolism; D000375:Aging / Q000473:pathology; D000818:Animals; D001007:Anxiety / Q000235:genetics / Q000523:psychology; D015153:Blotting, Western; D001923:Brain Chemistry / Q000502:physiology; D018450:Disease Progression; D005502:Food; D041981:Gastrointestinal Tract / Q000201:enzymology / Q000378:metabolism; D005838:Genotype; D006948:Hyperkinesis / Q000235:genetics / Q000523:psychology; D007150:Immunohistochemistry; D051379:Mice; D008822:Mice, Transgenic; D009043:Motor Activity / Q000502:physiology; D009474:Neurons / Q000502:physiology; D020734:Parkinsonian Disorders / Q000201:enzymology / Q000235:genetics* / Q000473:pathology*; D054648:Protein Phosphatase 2 / Q000378:metabolism; D012903:Smell / Q000502:physiology; D014446:Tyrosine 3-Monooxygenase / Q000378:metabolism; D051844:alpha-Synuclein / Q000235:genetics*
chemical_list: C497605:Snca protein, mouse; D051844:alpha-Synuclein; D014446:Tyrosine 3-Monooxygenase; D054648:Protein Phosphatase 2
keywords: enzymatic dysregulation; loss of a-Syn function; synucleinopathy