α-Synuclein modulation of Ca2+ signaling in human neuroblastoma (SH-SY5Y) cells |
| |
Authors: | Nishani T. Hettiarachchi,rew Parker,Mark L. Dallas,Kyla Pennington&dagger ,Chao-Chun Hung&dagger ,Hugh A. Pearson&Dagger ,John P. Boyle,Philip Robinson&dagger , Chris Peers |
| |
Affiliation: | Division of Cardiovascular and Neuronal Remodelling, Leeds Institute of Genetics, Health &Therapeutics, University of Leeds, Leeds, UK;;Leeds Institute for Molecular Medicine, Leeds, UK;;Faculty of Biological Sciences, University of Leeds, Leeds, UK |
| |
Abstract: | 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. |
| |
Keywords: | Ca2+ channel Ca2+ signaling neuroblastoma Parkinson's disease SH-SY5Y α-synuclein |
|
|