α-Synuclein modulation of Ca²⁺ signaling in human neuroblastoma (SH-SY5Y) cells

• Published in: Journal of neurochemistry 2009-12, Vol.111 (5), p.1192-1201
• Main Authors: Hettiarachchi, Nishani T, Parker, Andrew, Dallas, Mark L, Pennington, Kyla, Hung, Chao-Chun, Pearson, Hugh A, Boyle, John P, Robinson, Philip, Peers, Chris
• Format: Article
• Language: English
• Subjects: alpha-Synuclein - genetics; alpha-Synuclein - metabolism; Amino Acids - genetics; Analysis of Variance; Biological and medical sciences; Ca2+ channel; Ca2+ signaling; Calcium - metabolism; Calcium Channel Blockers - pharmacology; Calcium Channels, L-Type - metabolism; Calcium Signaling - drug effects; Calcium Signaling - genetics; Calcium Signaling - physiology; Ca²⁺ channel; Ca²⁺ signaling; Cell Line, Tumor; Cell Survival - genetics; Degenerative and inherited degenerative diseases of the nervous system. Leukodystrophies. Prion diseases; Enzyme Inhibitors - pharmacology; Fura-2; Gene Expression Regulation - drug effects; Gene Expression Regulation - genetics; Humans; Indoles - pharmacology; Medical sciences; Mutation - genetics; neuroblastoma; Neuroblastoma - metabolism; Neuroblastoma - pathology; Neuroblastoma - physiopathology; Neurology; Nifedipine - pharmacology; Oligomycins - pharmacology; omega-Conotoxin GVIA - pharmacology; Parkinson disease; Parkinson’s disease; Potassium Chloride - pharmacology; Serine - metabolism; SH-SY5Y; Transfection - methods; Tumors of the nervous system. Phacomatoses; α-synuclein
• ISSN: 0022-3042; 1471-4159
• DOI: 10.1111/j.1471-4159.2009.06411.x

Parkinson's disease (PD) is characterized in part by the presence of α-synuclein (α-syn) rich intracellular inclusions (Lewy bodies). Mutations and multiplication of the α-synuclein gene (SNCA) are associated with familial PD. Since Ca²⁺ dyshomeostasis may play an important role in the pathogenesis of PD, we used fluorimetry in fura-2 loaded SH-SY5Y cells to monitor Ca²⁺ homeostasis in cells stably transfected with either wild-type α-syn, the A53T mutant form, the S129D phosphomimetic mutant or with empty vector (which served as control). Voltage-gated Ca²⁺ influx evoked by exposure of cells to 50 mM K⁺ was enhanced in cells expressing all three forms of α-syn, an effect which was due specifically to increased Ca²⁺ entry via L-type Ca²⁺ channels. Mobilization of Ca²⁺ by muscarine was not strikingly modified by any of the α-syn forms, but they all reduced capacitative Ca²⁺ entry following store depletion caused either by muscarine or thapsigargin. Emptying of stores with cyclopiazonic acid caused similar rises of [Ca²⁺]i in all cells tested (with the exception of the S129D mutant), and mitochondrial Ca²⁺ content was unaffected by any form of α-synuclein. However, only WT α-syn transfected cells displayed significantly impaired viability. Our findings suggest that α-syn regulates Ca²⁺ entry pathways and, consequently, that abnormal α-syn levels may promote neuronal damage through dysregulation of Ca²⁺ homeostasis.