Skip to Content
Merck
  • Glutamate excitotoxicity in neurons triggers mitochondrial and endoplasmic reticulum accumulation of Parkin, and, in the presence of N-acetyl cysteine, mitophagy.

Glutamate excitotoxicity in neurons triggers mitochondrial and endoplasmic reticulum accumulation of Parkin, and, in the presence of N-acetyl cysteine, mitophagy.

Neurobiology of disease (2014-12-06)
Victor S Van Laar, Nikita Roy, Annie Liu, Swati Rajprohat, Beth Arnold, April A Dukes, Cory D Holbein, Sarah B Berman
ABSTRACT

Disruption of the dynamic properties of mitochondria (fission, fusion, transport, degradation, and biogenesis) has been implicated in the pathogenesis of neurodegenerative disorders, including Parkinson's disease (PD). Parkin, the product of gene PARK2 whose mutation causes familial PD, has been linked to mitochondrial quality control via its role in regulating mitochondrial dynamics, including mitochondrial degradation via mitophagy. Models using mitochondrial stressors in numerous cell types have elucidated a PINK1-dependent pathway whereby Parkin accumulates on damaged mitochondria and targets them for mitophagy. However, the role Parkin plays in regulating mitochondrial homeostasis specifically in neurons has been less clear. We examined whether a stressor linked to neurodegeneration, glutamate excitotoxicity, elicits Parkin-mitochondrial translocation and mitophagy in neurons. We found that brief, acute exposure to glutamate causes Parkin translocation to mitochondria in neurons, in a calcium- and N-methyl-d-aspartate (NMDA) receptor-dependent manner. In addition, we found that Parkin accumulates on endoplasmic reticulum (ER) and mitochondrial/ER junctions following excitotoxicity, supporting a role for Parkin in mitochondrial-ER crosstalk in mitochondrial homeostasis. Despite significant Parkin-mitochondria translocation, however, we did not observe mitophagy under these conditions. To further investigate, we examined the role of glutamate-induced oxidative stress in Parkin-mitochondria accumulation. Unexpectedly, we found that glutamate-induced accumulation of Parkin on mitochondria was promoted by the antioxidant N-acetyl cysteine (NAC), and that co-treatment with NAC facilitated Parkin-associated mitophagy. These results suggest the possibility that mitochondrial depolarization and oxidative damage may have distinct pathways associated with Parkin function in neurons, which may be critical in understanding the role of Parkin in neurodegeneration.

MATERIALS
Product Number
Brand
Product Description

Sigma-Aldrich
Water, HPLC Plus
Sigma-Aldrich
Water, suitable for HPLC
SAFC
HEPES
SAFC
HEPES
Supelco
HEPES, Pharmaceutical Secondary Standard; Certified Reference Material
Sigma-Aldrich
HEPES, anhydrous, free-flowing, Redi-Dri, ≥99.5%
Pure Water Density Standard, UKAS ISO/IEC17025 and ISO Guide 34 certified, density: 0.9982 g/mL at 20 °C, density: 0.9970 g/mL at 25 °C
Pure Water Density Standard, UKAS ISO/IEC17025 and ISO Guide 34 certified, density: 0.9982 g/mL at 20 °C, density: 0.9970 g/mL at 25 °C
Sigma-Aldrich
Water, BioPerformance Certified
Sigma-Aldrich
HEPES, Vetec, reagent grade, 99.5%
Glycine, European Pharmacopoeia (EP) Reference Standard
USP
Glycine, United States Pharmacopeia (USP) Reference Standard
Supelco
Water, for ultratrace analysis, ACS reagent
Sigma-Aldrich
Water, ACS reagent
Sigma-Aldrich
Water, Deionized
Sigma-Aldrich
HEPES, BioXtra, suitable for mouse embryo cell culture, ≥99.5% (titration)
Sigma-Aldrich
Amyloid Protein Non-Aβ Component, ≥80% (HPLC)
Sigma-Aldrich
HEPES, BioXtra, pH 5.0-6.5 (1 M in H2O), ≥99.5% (titration)
Sigma-Aldrich
Water, Nuclease-Free Water, for Molecular Biology
Sigma-Aldrich
E-Toxate Water, endotoxin, free
Sigma-Aldrich
Water, for embryo transfer, sterile-filtered, BioXtra, suitable for mouse embryo cell culture
Sigma-Aldrich
Hanks′ Balanced Salt Solution 10x, Without sodium bicarbonate, 10 ×, liquid, sterile-filtered, suitable for cell culture
SAFC
Glycine
Sigma-Aldrich
Glycine, 99%, FCC
Sigma-Aldrich
Water, tested according to Ph. Eur.
Supelco
Water, for HPCE, for luminescence, suitable for UV/Vis spectroscopy
Sigma-Aldrich
Water, for cell biology, sterile ultrafiltered
Sigma-Aldrich
Water, for molecular biology, sterile filtered
Sigma-Aldrich
HEPES, BioUltra, for molecular biology, ≥99.5% (T)
Sigma-Aldrich
Glycine, tested according to Ph. Eur.