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

Abstract

Parkinson's disease (PD) is characterized in part by the presence of a-synuclein (a-syn) rich intracellular inclusions (Lewy bodies). Mutations and multiplication of the a-synuclein gene (SNCA) are associated with familial PD. Since Ca 2+ dyshomeostasis may play an important role in the pathogenesis of PD, we used fluorimetry in fura-2 loaded SH-SY5Y cells to monitor Ca 2+ homeostasis in cells stably transfected with either wild-type a-syn, the A53T mutant form, the S129D phosphomimetic mutant or with empty vector (which served as control homeostasis.

α-Synuclein Controls Mitochondrial Calcium Homeostasis by Enhancing Endoplasmic Reticulum-Mitochondria Interactions

“…The reduction of the second peak in ␣-synoverexpressing cells is probably due to the effect of ␣-syn on Ca 2ϩ influx induced by store depletion as previously documented (see "Discussion" and Ref. 39).…”

The possible involvement of mitochondrial dysfunctions in Lewy body dementia: a systematic review

“…Alpha-synuclein works in the cell at multiple levels: it is involved in synaptic vesicle formation (Cooper et al, 2006) and in catecholamine metabolism in dopaminergic neurons (Mosharov et al, 2006); it interacts with the microtubule network (Branco et al, 2010) and, finally, it participates in calcium homeostasis regulation (Hettiarachchi et al, 2009). Mutations or polymorphisms in both mitochondrial DNA (mtDNA) and nuclear DNA have been implicated in causing DLB and PD, and also found in patients at risk of these conditions.…”

Responsiveness of voltage-gated calcium channels in SH-SY5Y human neuroblastoma cells on quasi-three-dimensional micropatterns formed with poly (l-lactic acid)

“…42,43 Using high K + depolarization and a Fura-2-based fluorescence imaging technique, Lambert et al 42 found that L-type channels may contribute to an increase in [Ca 2+ ] i in a wide range of depolarization (by 30 to 60 mM K + ) in SH-SY5Y cells, while N-type channels may only contribute to this increase at a higher depolarization (by 60 mM K + ). N-type channels have also been found to be fully inactivated in a dorsal root ganglion preparation at patch clamp, holding potentials positive to -50 mV.…”

“…44 Ca 2+ entry through L-type channels in SH-SY5Y cells has thus been suggested to play a major role in the rise in [Ca 2+ ] i in response to high K + depolarization. 42,43 Given the less negative resting membrane potential establishment (-20 to -40 mV) by undifferentiated SH-SY5Y cells 12,13,15,45 and the difference in VGCC responsiveness found with 50 mM K + depolarization in the present study, we accordingly focused on the L-type calcium channel expression for cells on both flat substrates and in microwell patterns using DM-BODIPY-based immunofluorescence staining. Figure 5 shows representative fluorescence images for cells on the flat substrate (A) and in the 100-0 (B) and 100-20 µm (C) microwell patterns stained with DM-BODIPY for L-type calcium channels.…”

“…As can be seen in Figure 5, cells on either the flat substrates or microwell patterns were all positively stained with DM-BODIPY, suggesting uniform expression of L-type calcium channels, which is in agreement with previous findings for this cell line. [40][41][42][43] For a comparison of the expression profiles, percentages of cells with strongly positive expression, as judged by a fluorescence intensity of the seventy-fifth percentile or higher within the percentile frequency distribution, were quantified and compared ( Figure 6). To reduce the laser exposure and fluorescence quenching during the capture of confocal images, the quantification was based on low magnification (20×) images.…”