title: Mutant eIF2B leads to impaired mitochondrial oxidative phosphorylation in vanishing white matter disease.
abstract: Eukaryotic translation initiation factor 2B (eIF2B) is a master regulator of protein synthesis under normal and stress conditions. Mutations in any of the five genes encoding its subunits lead to vanishing white matter (VWM) disease, a recessive genetic deadly illness caused by progressive loss of white matter in the brain. In this study we used fibroblasts, which are not involved in the disease, to demonstrate the involvement of eIF2B in mitochondrial function and abundance. Mass spectrometry of total proteome of mouse embryonic fibroblasts (MEFs) isolated from Eif2b5R132H/R132Hmice revealed unbalanced stoichiometry of proteins involved in oxidative phosphorylation and of mitochondrial translation machinery components, among others. Mutant MEFs exhibit 55% decrease in oxygen consumption rate per mtDNA content and 47% increase in mitochondrial abundance (p < 0.005), reflecting adaptation to energy requirements. A more robust eIF2B-associated oxidative respiration deficiency was found in mutant primary astrocytes, which exhibit > 3-fold lower ATP-linked respiration per cell despite a 2-fold increase in mtDNA content (p < 0.03). The 2-fold increase in basal and stimulated glycolysis in mutant astrocytes (p ≤ 0.03), but not in MEFs, demonstrates their higher energetic needs and further explicates their involvement in the disease. The data demonstrate the critical role of eIF2B in tight coordination of expression from nuclear and mitochondrial genomes and illuminates the importance of mitochondrial function in VWM pathology. Further dissection of the signaling network associated with eIF2B function will help generating therapeutic strategies for VWM disease and possibly other neurodegenerative disorders.
authors.affiliation: Department of Cell Research and Immunology, George S. Wise Faculty of Life Sciences, Tel Aviv University, Tel Aviv, Israel.
authors.forename: Gali
authors.initials: G
authors.lastname: Raini
authors.affiliation: Department of Cell Research and Immunology, George S. Wise Faculty of Life Sciences, Tel Aviv University, Tel Aviv, Israel.
authors.forename: Reut
authors.initials: R
authors.lastname: Sharet
authors.affiliation: Department of Cell Research and Immunology, George S. Wise Faculty of Life Sciences, Tel Aviv University, Tel Aviv, Israel.
authors.forename: Melisa
authors.initials: M
authors.lastname: Herrero
authors.affiliation: Department of Cell Research and Immunology, George S. Wise Faculty of Life Sciences, Tel Aviv University, Tel Aviv, Israel.
authors.forename: Andrea
authors.initials: A
authors.lastname: Atzmon
authors.affiliation: Department of Human Molecular Genetics and Biochemistry, Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv, Israel.
authors.forename: Anjana
authors.initials: A
authors.lastname: Shenoy
authors.affiliation: Department of Human Molecular Genetics and Biochemistry, Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv, Israel.
authors.forename: Tamar
authors.initials: T
authors.lastname: Geiger
authors.affiliation: Department of Cell Research and Immunology, George S. Wise Faculty of Life Sciences, Tel Aviv University, Tel Aviv, Israel.|Sagol School of Neuroscience, Tel Aviv University, Tel Aviv, Israel.
authors.forename: Orna
authors.identifier: 0000-0002-3716-1540
authors.initials: O
authors.lastname: Elroy-Stein
mesh_terms: D000818:Animals; D000831:Animals, Newborn; D000968:Antimycin A / Q000494:pharmacology; D001253:Astrocytes / Q000187:drug effects / Q000502:physiology / Q000648:ultrastructure*; D002259:Carbonyl Cyanide p-Trifluoromethoxyphenylhydrazone / Q000494:pharmacology; D002453:Cell Cycle / Q000187:drug effects / Q000235:genetics; D048429:Cell Size; D002478:Cells, Cultured; D002701:Chloramphenicol / Q000494:pharmacology; D020717:Eukaryotic Initiation Factor-2B / Q000235:genetics* / Q000378:metabolism; D005260:Female; D005347:Fibroblasts / Q000187:drug effects / Q000276:immunology / Q000648:ultrastructure; D006649:Histocompatibility Antigens / Q000378:metabolism; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL; D008822:Mice, Transgenic; D008928:Mitochondria / Q000235:genetics* / Q000502:physiology; D009154:Mutation / Q000235:genetics*; D010085:Oxidative Phosphorylation / Q000187:drug effects; D010101:Oxygen Consumption / Q000187:drug effects / Q000235:genetics*; D010766:Phosphorylation / Q000187:drug effects / Q000235:genetics; D014176:Protein Biosynthesis / Q000187:drug effects / Q000235:genetics; D011500:Protein Synthesis Inhibitors / Q000494:pharmacology; D061209:Proton Ionophores / Q000494:pharmacology; D017382:Reactive Oxygen Species / Q000378:metabolism
chemical_list: D020717:Eukaryotic Initiation Factor-2B; D006649:Histocompatibility Antigens; D011500:Protein Synthesis Inhibitors; D061209:Proton Ionophores; D017382:Reactive Oxygen Species; D002259:Carbonyl Cyanide p-Trifluoromethoxyphenylhydrazone; D000968:Antimycin A; D002701:Chloramphenicol
keywords: VWM disease; eIF2B; mitochondria; oxidative phosphorylation; translation