alpha-Synuclein modulation of Ca2+ signaling in human neuroblastoma (SH-SY5Y) cells.
Parkinson's disease (PD) is characterized in part by the presence of alpha-synuclein (alpha-syn) rich intracellular inclusions (Lewy bodies). Mutations and multiplication of the alpha-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 alpha-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 alpha-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 alpha-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 alpha-synuclein. However, only WT alpha-syn transfected cells displayed significantly impaired viability. Our findings suggest that alpha-syn regulates Ca2+ entry pathways and, consequently, that abnormal alpha-syn levels may promote neuronal damage through dysregulation of Ca2+ homeostasis.
Division of Cardiovascular and Neuronal Remodelling, Leeds Institute of Genetics, Health & Therapeutics, University of Leeds, Leeds, UK.
Nishani T
NT
Hettiarachchi
Andrew
A
Parker
Mark L
ML
Dallas
Kyla
K
Pennington
Chao-Chun
CC
Hung
Hugh A
HA
Pearson
John P
JP
Boyle
Philip
P
Robinson
Chris
C
Peers
D000596:Amino Acids / Q000235:genetics; D000704:Analysis of Variance; D002118:Calcium / Q000378:metabolism*; D002121:Calcium Channel Blockers / Q000494:pharmacology; D020746:Calcium Channels, L-Type / Q000378:metabolism; D020013:Calcium Signaling / Q000187:drug effects / Q000235:genetics / Q000502:physiology*; D045744:Cell Line, Tumor; D002470:Cell Survival / Q000235:genetics; D004791:Enzyme Inhibitors / Q000494:pharmacology; D016257:Fura-2; D005786:Gene Expression Regulation / Q000187:drug effects / Q000235:genetics; D006801:Humans; D007211:Indoles / Q000494:pharmacology; D009154:Mutation / Q000235:genetics; D009447:Neuroblastoma / Q000378:metabolism* / Q000473:pathology / Q000503:physiopathology; D009543:Nifedipine / Q000494:pharmacology; D009840:Oligomycins / Q000494:pharmacology; D011189:Potassium Chloride / Q000494:pharmacology; D012694:Serine / Q000378:metabolism; D014162:Transfection / Q000379:methods; D051844:alpha-Synuclein / Q000235:genetics / Q000378:metabolism*; D020866:omega-Conotoxin GVIA / Q000494:pharmacology
D000596:Amino Acids; D002121:Calcium Channel Blockers; D020746:Calcium Channels, L-Type; D004791:Enzyme Inhibitors; D007211:Indoles; C419385:L-type calcium channel alpha(1C); D009840:Oligomycins; D051844:alpha-Synuclein; D012694:Serine; D011189:Potassium Chloride; D020866:omega-Conotoxin GVIA; D009543:Nifedipine; D002118:Calcium; D016257:Fura-2; C000543:cyclopiazonic acid