EPT1 (selenoprotein I) is critical for the neural development and maintenance of plasmalogen in humans

Yasuhiro Horibata, Orly Elpeleg, Ayelet Eran, Yoshio Hirabayashi, David Savitzki, Galit Tal, Hanna Mandel, Hiroyuki Sugimoto

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76 Scopus citations

Abstract

Ethanolamine phosphotransferase (EPT)1, also known as selenoprotein 1 (SELENOI), is an enzyme that transfers phosphoethanolamine from cytidine diphosphate-ethanolamine to lipid acceptors to produce ethanolamine glycerophospholipids, such as diacyl-linked phosphatidylethanolamine (PE) and ether-linked plasmalogen [1-alkenyl-2-acyl-glycerophosphoethanolamine (plasmenyl-PE)]. However, to date there has been no analysis of the metabolomic consequences of the mutation of EPT1 on the concentration of ethanolamine glycerophospholipids in mammalian cells. We studied a patient with severe complicated hereditary spastic paraplegia, sensorineural-deafness, blindness, and seizures. Neuroimaging revealed hypomyelination, followed by brain atrophy mainly in the cerebellum and brainstem. Using whole exome sequencing, we identified a novel EPT1 mutation (exon skipping). In vitro EPT activity, as well as the rate of biosynthesis of ethanolamine glycerophospholipids, was markedly reduced in cultures of the patient’s skin fibroblasts. Quantification of phospholipids by LC-MS/MS demonstrated reduced levels of several PE species with polyunsaturated fatty acids, such as 38:6, 38:4, 40:6, 40:5, and 40:4. Notably, most plasmenyl-PE species were significantly decreased in the patient’s cells, whereas most plasmanylcholine [1-alkyl-2-acyl-glycerophosphocholine (plasmanyl-PC)] species were increased. Similar findings regarding decreased plasmenyl-PE and increased plasmanyl-PC were obtained using EPT1-KO HeLa cells. Our data demonstrate for the first time the indispensable role of EPT1 in the myelination process and neurodevelopment, and in the maintenance of normal homeostasis of ether-linked phospholipids in humans.

Original languageEnglish
Pages (from-to)1015-1026
Number of pages12
JournalJournal of Lipid Research
Volume59
Issue number6
DOIs
StatePublished - Jun 2018
Externally publishedYes

Bibliographical note

Publisher Copyright:
Copyright © 2018 by the American Society for Biochemistry and Molecular Biology, Inc.

Funding

This work was supported in part by Japan Society for the Promotion of Science Grant 17K08642. The authors declare no competing financial interests. Manuscript received 1 November 2017 and in revised form 1 March 2018. Published, JLR Papers in Press, March 2, 2018 DOI https://doi.org/10.1194/jlr.P081620

FundersFunder number
Japan Society for the Promotion of Science15K08284, 17K08642

    Keywords

    • Ethanolamine phosphotransferase 1
    • Hereditary spastic paraplegia
    • Neurodegenerative disease
    • Phospholipids/biosynthesis
    • Phospholipids/metabolism
    • Phospholipids/phosphatidylcholine
    • Phospholipids/phosphatidylethanolamine
    • Whole exome sequencing

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