Dataset Information

Na⁺/Ca²⁺ exchanger isoform 1 takes part to the Ca²⁺-related prosurvival pathway of SOD1 in primary motor neurons exposed to beta-methylamino-L-alanine.

ABSTRACT:

Background

The cycad neurotoxin beta-methylamino-L-alanine (L-BMAA), one of the environmental trigger factor for amyotrophic lateral sclerosis/Parkinson-dementia complex (ALS/PDC), may cause neurodegeneration by disrupting organellar Ca²⁺ homeostasis. Through the activation of Akt/ERK1/2 pathway, the Cu,Zn-superoxide dismutase (SOD1) and its non-metallated form, ApoSOD1, prevent endoplasmic reticulum (ER) stress-induced cell death in motor neurons exposed to L-BMAA. This occurs through the rapid increase of intracellular Ca²⁺ concentration ([Ca²⁺]_i) in part flowing from the extracellular compartment and in part released from ER. However, the molecular components of this mechanism remain uncharacterized.

Methods

By an integrated approach consisting on the use of siRNA strategy, Western blotting, confocal double- labeling immunofluorescence, patch-clamp electrophysiology, and Fura 2-/SBFI-single-cell imaging, we explored in rat motor neuron-enriched cultures the involvement of the plasma membrane proteins Na⁺/Ca²⁺ exchanger (NCX) and purinergic P₂X₇ receptor as well as that of the intracellular cADP-ribose (cADPR) pathway, in the neuroprotective mechanism of SOD1.

Results

We showed that SOD1-induced [Ca²⁺]_i rise was prevented neither by A430879, a P₂X₇ receptor specific antagonist or 8-bromo-cADPR, a cell permeant antagonist of cADP-ribose, but only by the pan inhibitor of NCX, CB-DMB. The same occurred for the ApoSOD1. Confocal double labeling immunofluorescence showed a huge expression of plasmalemmal NCX1 and intracellular NCX3 isoforms. Furthermore, we identified NCX1 reverse mode as the main mechanism responsible for the neuroprotective ER Ca²⁺ refilling elicited by SOD1 and ApoSOD1 through which they promoted translocation of active Akt in the nuclei of a subset of primary motor neurons. Finally, the activation of NCX1 by the specific agonist CN-PYB2 protected motor neurons from L-BMAA-induced cell death, mimicking the effect of SOD1.

Conclusion

Collectively, our data indicate that SOD1 and ApoSOD1 exert their neuroprotective effect by modulating ER Ca²⁺ content through the activation of NCX1 reverse mode and Akt nuclear translocation in a subset of primary motor neurons. Video Abstract.

SUBMITTER: Petrozziello T

PROVIDER: S-EPMC8756626 | biostudies-literature |

REPOSITORIES: biostudies-literature

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Project description:Introduction: Safranal, which endows saffron its unique aroma, causes vasodilatation and has a hypotensive effect in animal studies, but the mechanisms of these effects are unknown. In this study, we investigated the mechanisms of safranal vasodilation. Methods: Isolated rat endothelium-intact or -denuded aortic rings were precontracted with phenylephrine and then relaxed with safranal. To further assess the involvement of nitric oxide, prostaglandins, guanylate cyclase, and phospholipase A2 in safranal-induced vasodilation, aortic rings were preincubated with L-NAME, indomethacin, methylene blue, or quinacrine, respectively, then precontracted with phenylephrine, and safranal concentration-response curves were established. To explore the effects of safranal on Ca2+ influx, phenylephrine and CaCl2 concentration-response curves were established in the presence of safranal. Furthermore, the effect of safranal on aortic rings in the presence of ouabain, a Na+-K+ ATPase inhibitor, was studied to explore the contribution of Na+/Ca2+ exchanger to this vasodilation. Results: Safranal caused vasodilation in endothelium-intact and endothelium-denuded aortic rings. The vasodilation was not eliminated by pretreatment with L-NAME, indomethacin, methylene blue, or quinacrine, indicating the lack of a role for NO/cGMP. Safranal significantly inhibited the maximum contractions induced by phenylephrine, or by CaCl2 in Ca2+-free depolarizing buffer. Safranal also relaxed contractions induced by ouabain, but pretreatment with safranal totally abolished the development of ouabain contractions. Discussion/Conclusion: Inhibition of Na+-K+ ATPase by ouabain leads to the accumulation of Na+ intracellularly, forcing the Na+/Ca2+ exchanger to work in reverse mode, thus causing a contraction. Inhibition of the development of this contraction by preincubation with safranal indicates that safranal inhibited the Na+/Ca2+ exchanger. We conclude that safranal vasodilation is mediated by the inhibition of calcium influx from extracellular space through L-type Ca2+ channels and by the inhibition of the Na+/Ca2+ exchanger.

Dataset Information

Na⁺/Ca²⁺ exchanger isoform 1 takes part to the Ca²⁺-related prosurvival pathway of SOD1 in primary motor neurons exposed to beta-methylamino-L-alanine.

Background

Methods

Results

Conclusion

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OmicsDI is part of the ELIXIR infrastructure

Tweets

Dataset Information

Na+/Ca2+ exchanger isoform 1 takes part to the Ca2+-related prosurvival pathway of SOD1 in primary motor neurons exposed to beta-methylamino-L-alanine.

Background

Methods

Results

Conclusion

Similar Datasets

OmicsDI is part of the ELIXIR infrastructure

Tweets

Na⁺/Ca²⁺ exchanger isoform 1 takes part to the Ca²⁺-related prosurvival pathway of SOD1 in primary motor neurons exposed to beta-methylamino-L-alanine.