Sphingolipid desaturase DEGS1 is essential for mitochondria-associated membrane integrity
Por:
Planas-Serra L, Launay N, Goicoechea L, Heron B, Jou-Munoz C, Julià-Palacios NA, Ruiz M, Fourcade S, Casasnovas C, De La Torre C, Gelot A, Marsal M, Loza-Alvarez P, Garcia-Cazorla A, Fatemi A, Ferrer I, Portero-Otin M, Area-Gómez E and Pujol A
Publicada:
15 may 2023
Ahead of Print:
15 may 2023
Categoría:
Medicine (miscellaneous)
Resumen:
Sphingolipids function as membrane constituents and signaling molecules, with crucial roles in human diseases, from neurodevelopmental disorders to cancer, best exemplified in the inborn errors of sphingolipid metabolism in lysosomes. The dihydroceramide desaturase Delta 4-dihydroceramide desaturase 1 (DEGS1) acts in the last step of a sector of the sphingolipid pathway, de novo ceramide biosynthesis. Defects in DEGS1 cause the recently described hypomyelinating leukodystrophy-18 (HLD18) (OMIM #618404). Here, we reveal that DEGS1 is a mitochondria-associated endoplasmic reticulum membrane-resident (MAM-resident) enzyme, refining previous reports locating DEGS1 at the endoplasmic reticulum only. Using patient fibroblasts, multiomics, and enzymatic assays, we show that DEGS1 deficiency disrupts the main core functions of the MAM: (a) mitochondrial dynamics, with a hyperfused mitochondrial network associated with decreased activation of dynamin-related protein 1; (b) cholesterol metabolism, with impaired sterol O-acyltransferase activity and decreased cholesteryl esters; (c) phospholipid metabolism, with increased phosphatidic acid and phosphatidylserine and decreased phosphatidylethanolamine; and (d) biogenesis of lipid droplets, with increased size and numbers. Moreover, we detected increased mitochondrial superoxide species production in fibroblasts and mitochondrial respiration impairment in patient muscle biopsy tissues. Our findings shed light on the pathophysiology of HLD18 and broaden our understanding of the role of sphingolipid metabolism in MAM function.
Filiaciones:
Planas-Serra L:
Neurometabolic Diseases Laboratory, Bellvitge Biomedical Research Institute (IDIBELL), Barcelona, Spain
Launay N:
Neurometabolic Diseases Laboratory, Bellvitge Biomedical Research Institute (IDIBELL), Barcelona, Spain
Goicoechea L:
Neurometabolic Diseases Laboratory, Bellvitge Biomedical Research Institute (IDIBELL), Barcelona, Spain
Heron B:
Service de Neuropédiatrie, Hôpital Armand-Trousseau, Paris, France
Jou-Munoz C:
Neurology and Pathology Department, Hospital Sant Joan de Déu, Barcelona, Spain
Julià-Palacios NA:
Neurology and Pathology Department, Hospital Sant Joan de Déu, Barcelona, Spain
Ruiz M:
Neurometabolic Diseases Laboratory, Bellvitge Biomedical Research Institute (IDIBELL), Barcelona, Spain
Fourcade S:
Neurometabolic Diseases Laboratory, Bellvitge Biomedical Research Institute (IDIBELL), Barcelona, Spain
Casasnovas C:
Neurometabolic Diseases Laboratory, Bellvitge Biomedical Research Institute (IDIBELL), Barcelona, Spain
De La Torre C:
Proteomic & Immortalization Unit, Josep Carreras Leukaemia Research Institute Barcelona, Barcelona, Spain
Gelot A:
Service de Neuropédiatrie, Hôpital Armand-Trousseau, Paris, France
Marsal M:
SLN Facility, ICFO-Institut de Ciencies Fotoniques, Castelldefels, Spain
Loza-Alvarez P:
SLN Facility, ICFO-Institut de Ciencies Fotoniques, Castelldefels, Spain
Garcia-Cazorla A:
Neurology and Pathology Department, Hospital Sant Joan de Déu, Barcelona, Spain
Fatemi A:
Department of Neurology and Pediatrics, The Kennedy Krieger Institute, Baltimore, United States of America
Ferrer I:
Institut de Neuropatologia, IDIBELL-University of Barcelona, Barcelona, Spain
Portero-Otin M:
Metabolism, IRBLLEIDA, lleida, Spain
Area-Gómez E:
Department of Neurology, Columbia University College of Physicians and Surgeons, New York, United States of America
Pujol A:
Bellvitge Biomedical Research Institute (IDIBELL), Barcelona, Spain
Green Submitted, gold
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