Abstract |
Mutations in the PLA2G6 gene which encodes Ca(2+)-independent phospholipase A2 (VIA iPLA2) were detected in 85% of cases of the inherited degenerative nervous system disorder INAD ( infantile neuroaxonal dystrophy, OMIM #256600). However, molecular mechanisms linking these mutations to the disease progression are unclear. VIA iPLA2 is expressed also in mitochondria. Here, we investigate Ca(2+) handling by brain mitochondria derived from mice with hypomorph Pla2g6 allele. These animals with reduced transcript levels (5% of wild type) represent a suitable model for INAD. We demonstrated significant reduction of Ca(2+) uptake rate and Ca(2+) retention capacity in brain mitochondria isolated from this mutant. This phenotype could be mimicked when in wild-type controls VIA iPLA2 was inhibited by S-BEL. Importantly, the reduction could be ameliorated partly by addition of the VIA iPLA2 product, sn-2 lysophosphatidyl- choline. Furthermore, we demonstrated in situ a reduced mitochondrial potential in neurons from mice deficient in VIA iPLA2, which could cause the reduced Ca(2+) uptake rate via the potential-dependent mitochondrial Ca(2+) uniporter. Thus, the disturbances in mitochondrial potential and the changes in Ca(2+) handling were dependent on VIA iPLA2 activity. Reduced mitochondrial Ca(2+) uptake rate and Ca(2+) retention capacity might result in increased vulnerability of mitochondria to the Ca(2+) overload and in disturbed cellular Ca(2+) signaling during INAD. For VIA iPLA2, non-canonical functions beyond sole phospholipid turnover seem to be important, such as regulation of store-operated Ca(2+) entry in cells. Thus, our findings bring new insight into molecular mechanism affected in INAD and highlight the non-canonical function of VIA iPLA2 in regulation of mitochondrial Ca(2+) handling.
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Authors | Mikhail Strokin, Georg Reiser |
Journal | Neurochemistry international
(Neurochem Int)
Vol. 99
Pg. 187-193
(10 2016)
ISSN: 1872-9754 [Electronic] England |
PMID | 27395788
(Publication Type: Journal Article, Research Support, Non-U.S. Gov't)
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Copyright | Copyright © 2016. Published by Elsevier Ltd. |
Chemical References |
- Group VI Phospholipases A2
- Pla2g6 protein, mouse
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Topics |
- Animals
- Calcium Signaling
(physiology)
- Disease Models, Animal
- Group VI Phospholipases A2
(genetics, metabolism)
- Humans
- Mice
- Mice, Inbred C57BL
- Mice, Transgenic
- Mitochondria
(genetics, metabolism)
- Neuroaxonal Dystrophies
(genetics, metabolism)
- Rats
- Rats, Wistar
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