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

J Neurochem. 2009 Dec;111(5):1192-201. doi: 10.1111/j.1471-4159.2009.06411.x. Epub 2009 Oct 5.

Abstract

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.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Amino Acids / genetics
  • Analysis of Variance
  • Calcium / metabolism*
  • Calcium Channel Blockers / pharmacology
  • Calcium Channels, L-Type / metabolism
  • Calcium Signaling / drug effects
  • Calcium Signaling / genetics
  • Calcium Signaling / physiology*
  • Cell Line, Tumor
  • Cell Survival / genetics
  • Enzyme Inhibitors / pharmacology
  • Fura-2
  • Gene Expression Regulation / drug effects
  • Gene Expression Regulation / genetics
  • Humans
  • Indoles / pharmacology
  • Mutation / genetics
  • Neuroblastoma / metabolism*
  • Neuroblastoma / pathology
  • Neuroblastoma / physiopathology
  • Nifedipine / pharmacology
  • Oligomycins / pharmacology
  • Potassium Chloride / pharmacology
  • Serine / metabolism
  • Transfection / methods
  • alpha-Synuclein / genetics
  • alpha-Synuclein / metabolism*
  • omega-Conotoxin GVIA / pharmacology

Substances

  • Amino Acids
  • Calcium Channel Blockers
  • Calcium Channels, L-Type
  • Enzyme Inhibitors
  • Indoles
  • L-type calcium channel alpha(1C)
  • Oligomycins
  • alpha-Synuclein
  • Serine
  • Potassium Chloride
  • omega-Conotoxin GVIA
  • Nifedipine
  • Calcium
  • Fura-2
  • cyclopiazonic acid