title: IDH1 regulates phospholipid metabolism in developing astrocytes.
abstract: Isocitrate dehydrogenase 1 (IDH1) is an evolutionarily conserved enzyme that catalyzes the interconversion of isocitrate to α-ketoglutarate with the concomitant reduction of NADP(+) to NADPH. IDH1 has previously been shown to participate in lipid biosynthesis in various tissues such as the liver and adipose tissue. We examined the potential role of IDH1 in phospholipid metabolism in the brain. Here we show that IDH1 is highly expressed in the brain and astrocytes during embryonic development and the postnatal period and subsequently declines in adulthood. Silencing of IDH1 expression using siRNA in astrocytes isolated from E18.5 mouse cortices led to increased incorporation of [(3)H]-palmitate into the phosphatidylcholines (PCs) and decreased the incorporation of [(3)H]-palmitate into sphingomyelin and the phosphatidylethanolamines (PEs). In pulse-chase experiments, knock-down of IDH1 expression impaired the turnover of PCs and decreased the synthesis of PEs. The decrease in [(3)H]-palmitate incorporation into PEs when IDH1 was knocked-down in astrocytes was not due to impairments within the CDP-ethanolamine pathway or in the rate of decarboxylation of phosphatidylserine (PS). In conclusion, our results reveal a role for IDH1 in the synthesis/turnover of phospholipids in developing astrocytes and highlight the lipid alterations resulting from the loss of wild-type IDH1 activity.
authors.affiliation: Sunnybrook Research Institute, Sunnybrook Health Sciences Centre, 2075 Bayview Ave, D704, Toronto, ON, Canada M4N 3M5. Electronic address: elena.bogdanovic@utoronto.ca.
authors.forename: Elena
authors.initials: E
authors.lastname: Bogdanovic
authors.affiliation: Sunnybrook Research Institute, Sunnybrook Health Sciences Centre, 2075 Bayview Ave, D704, Toronto, ON, Canada M4N 3M5. Electronic address: sadri94@yahoo.ca.
authors.forename: Ali-Reza
authors.initials: AR
authors.lastname: Sadri
authors.affiliation: Sunnybrook Research Institute, Sunnybrook Health Sciences Centre, 2075 Bayview Ave, D704, Toronto, ON, Canada M4N 3M5. Electronic address: mcatapano@live.com.
authors.forename: Michael
authors.initials: M
authors.lastname: Catapano
authors.affiliation: Group on the Molecular and Cell Biology of Lipids, Department of Medicine, University of Alberta, 332 HMRC, Edmonton, AB, Canada T6G 2S2. Electronic address: jvance@ualberta.ca.
authors.forename: Jean E
authors.initials: JE
authors.lastname: Vance
authors.affiliation: Sunnybrook Research Institute, Sunnybrook Health Sciences Centre, 2075 Bayview Ave, D704, Toronto, ON, Canada M4N 3M5. Electronic address: marc.jeschke@sunnybrook.ca.
authors.forename: Marc G
authors.initials: MG
authors.lastname: Jeschke
mesh_terms: D000818:Animals; D001253:Astrocytes / Q000378:metabolism*; D001921:Brain / Q000166:cytology* / Q000196:embryology / Q000254:growth & development; D055785:Gene Knockdown Techniques; D007521:Isocitrate Dehydrogenase / Q000235:genetics / Q000378:metabolism*; D050356:Lipid Metabolism; D008807:Mice, Inbred BALB C; D009928:Organ Specificity; D010743:Phospholipids / Q000378:metabolism*
chemical_list: D010743:Phospholipids; D007521:Isocitrate Dehydrogenase
keywords: Astrocyte; Brain; Embryo; IDH1; Phospholipid