title: Alpha-synuclein aggregation and cell death triggered by energy deprivation and dopamine overload are counteracted by D2/D3 receptor activation.
abstract: Progressive degeneration and intraneuronal Lewy bodies made of filamentous alpha-synuclein (alpha-syn) in dopaminergic cells of the nigrostriatal system are characteristics of Parkinson's disease (PD). Glucose uptake is reduced in some of the brain regions affected by PD neurodegenerative changes. Defects in mitochondrial activity in the substantia nigra have been observed in the brain of patients affected by PD and substantia nigra lesions can induce the onset of a secondary parkinsonism. Thus, energy starvation and consequently metabolic impairment to dopaminergic neurons may be related to the onset of PD. On this line, we evaluated the effect of nutrient starvation, reproduced 'in vitro' by glucose deprivation (GD), in primary mesecephalic neuronal cultures and dopaminergic-differentiated SH-SY5Y cells, to evaluate if decreased glucose support to dopaminergic cells can lead to mitochondrial damage, neurodegeneration and alpha-syn misfolding. Furthermore, we investigated the effect of dopamine (DA) treatment in the presence of a DA-uptake inhibitor or of the D(2)/D(3) receptor (D(2)R/D(3)R) agonist quinpirole on GD-treated cells, to evaluate the efficacy of these therapeutic compounds. We found that GD induced the formation of fibrillary aggregated alpha-syn inclusions containing the DA transporter in dopaminergic cells. These alterations were accompanied by dopaminergic cell death and were exacerbated by DA overload. Conversely, the block of DA uptake and D(2)R/D(3)R agonist treatment exerted neuroprotective effects. These data indicate that glucose starvation is likely involved in the induction of PD-related pathological changes in dopaminergic neurons. These changes may be counteracted by the block of DA uptake and by dopaminergic agonist treatment.
authors.affiliation: Division of Pharmacology, Department of Biomedical Sciences and Biotechnology, University of Brescia, Brescia, Italy. bellucci@med.unibs.it
authors.forename: Arianna
authors.initials: A
authors.lastname: Bellucci
authors.forename: Ginetta
authors.initials: G
authors.lastname: Collo
authors.forename: Ilenia
authors.initials: I
authors.lastname: Sarnico
authors.forename: Leontino
authors.initials: L
authors.lastname: Battistin
authors.forename: Cristina
authors.initials: C
authors.lastname: Missale
authors.forename: Pierfranco
authors.initials: P
authors.lastname: Spano
mesh_terms: D000704:Analysis of Variance; D000818:Animals; D052160:Benzothiazoles; D016923:Cell Death / Q000187:drug effects / Q000502:physiology; D002478:Cells, Cultured; D004298:Dopamine / Q000378:metabolism* / Q000494:pharmacology; D015259:Dopamine Agents / Q000494:pharmacology; D050483:Dopamine Plasma Membrane Transport Proteins / Q000378:metabolism; D004622:Embryo, Mammalian; D005562:Formazans / Q000378:metabolism; D005786:Gene Expression Regulation / Q000187:drug effects / Q000502:physiology; D005947:Glucose / Q000172:deficiency*; D008636:Mesencephalon / Q000166:cytology; D051379:Mice; D008928:Mitochondria / Q000187:drug effects / Q000473:pathology; D009410:Nerve Degeneration / Q000209:etiology*; D009419:Nerve Tissue Proteins / Q000378:metabolism; D009474:Neurons / Q000187:drug effects / Q000378:metabolism; D021381:Protein Transport / Q000187:drug effects; D017448:Receptors, Dopamine D2 / Q000502:physiology*; D013778:Tetrazolium Salts / Q000378:metabolism; D013844:Thiazoles / Q000378:metabolism; D051844:alpha-Synuclein / Q000378:metabolism*
chemical_list: D052160:Benzothiazoles; D015259:Dopamine Agents; D050483:Dopamine Plasma Membrane Transport Proteins; D005562:Formazans; D009419:Nerve Tissue Proteins; D017448:Receptors, Dopamine D2; D013778:Tetrazolium Salts; D013844:Thiazoles; D051844:alpha-Synuclein; C079782:MTT formazan; C009462:thioflavin T; D005947:Glucose; D004298:Dopamine