Loss of PLA2G6 leads to elevated mitochondrial lipid peroxidation and mitochondrial dysfunction
Author(s)
Type
Journal Article
Abstract
The PLA2G6 gene encodes a group VIA calcium-independent phospholipase A2 beta enzyme that selectively hydrolyses glycerophospholipids to release free fatty acids. Mutations in PLA2G6 have been associated with disorders such as infantile neuroaxonal dystrophy, neurodegeneration with brain iron accumulation type II and Karak syndrome. More recently, PLA2G6 was identified as the causative gene in a subgroup of patients with autosomal recessive early-onset dystonia-parkinsonism. Neuropathological examination revealed widespread Lewy body pathology and the accumulation of hyperphosphorylated tau, supporting a link between PLA2G6 mutations and parkinsonian disorders. Here we show that knockout of the Drosophila homologue of the PLA2G6 gene, iPLA2-VIA, results in reduced survival, locomotor deficits and organismal hypersensitivity to oxidative stress. Furthermore, we demonstrate that loss of iPLA2-VIA function leads to a number of mitochondrial abnormalities, including mitochondrial respiratory chain dysfunction, reduced ATP synthesis and abnormal mitochondrial morphology. Moreover, we show that loss of iPLA2-VIA is strongly associated with increased lipid peroxidation levels. We confirmed our findings using cultured fibroblasts taken from two patients with mutations in the PLA2G6 gene. Similar abnormalities were seen including elevated mitochondrial lipid peroxidation and mitochondrial membrane defects, as well as raised levels of cytoplasmic and mitochondrial reactive oxygen species. Finally, we demonstrated that deuterated polyunsaturated fatty acids, which inhibit lipid peroxidation, were able to partially rescue the locomotor abnormalities seen in aged flies lacking iPLA2-VIA gene function, and restore mitochondrial membrane potential in fibroblasts from patients with PLA2G6 mutations. Taken together, our findings demonstrate that loss of normal PLA2G6 gene activity leads to lipid peroxidation, mitochondrial dysfunction and subsequent mitochondrial membrane abnormalities. Furthermore we show that the iPLA2-VIA knockout fly model provides a useful platform for the further study of PLA2G6-associated neurodegeneration.
Date Issued
2015-07
Date Acceptance
2015-03-17
Citation
Brain, 2015, 138, pp.1801-1816
ISSN
1460-2156
Publisher
Oxford University Press
Start Page
1801
End Page
1816
Journal / Book Title
Brain
Volume
138
Copyright Statement
© The Author (2015). Published by Oxford University Press on behalf of the Guarantors of Brain. This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/4.0/), which permits unrestricted reuse, distribution, and reproduction in any medium, provided the original work is properly cited.
License URL
Identifier
PII: awv132
Subjects
Drosophila
PLA2G6
infantile neuroaxonal dystrophy
neurodegeneration with brain iron accumulation
Animals
Cell Line
Drosophila Proteins
Drosophila melanogaster
Fibroblasts
Gene Knockout Techniques
Group VI Phospholipases A2
Group X Phospholipases A2
Humans
Lipid Peroxidation
Mass Spectrometry
Membrane Potential, Mitochondrial
Microscopy, Fluorescence
Mitochondria
Neurodegenerative Diseases
Oxidative Stress
Reverse Transcriptase Polymerase Chain Reaction
Neurology & Neurosurgery
11 Medical And Health Sciences
17 Psychology And Cognitive Sciences
Publication Status
Published