title: Oxaloacetate enhances neuronal cell bioenergetic fluxes and infrastructure.
abstract: We tested how the addition of oxaloacetate (OAA) to SH-SY5Y cells affected bioenergetic fluxes and infrastructure, and compared the effects of OAA to malate, pyruvate, and glucose deprivation. OAA displayed pro-glycolysis and pro-respiration effects. OAA pro-glycolysis effects were not a consequence of decarboxylation to pyruvate because unlike OAA, pyruvate lowered the glycolysis flux. Malate did not alter glycolysis flux and reduced mitochondrial respiration. Glucose deprivation essentially eliminated glycolysis and increased mitochondrial respiration. OAA increased, while malate decreased, the cell NAD+/NADH ratio. Cytosolic malate dehydrogenase 1 protein increased with OAA treatment, but not with malate or glucose deprivation. Glucose deprivation increased protein levels of ATP citrate lyase, an enzyme which produces cytosolic OAA, whereas OAA altered neither ATP citrate lyase mRNA nor protein levels. OAA, but not glucose deprivation, increased cytochrome oxidase subunit 2, PGC1α, PGC1β, and PGC1 related co-activator protein levels. OAA increased total and phosphorylated SIRT1 protein. We conclude that adding OAA to SH-SY5Y cells can support or enhance both glycolysis and respiration fluxes. These effects appear to depend, at least partly, on OAA causing a shift in the cell redox balance to a more oxidized state, that it is not a glycolysis pathway intermediate, and possibly its ability to act in an anaplerotic fashion. We examined how oxaloacetate (OAA) affects bioenergetic fluxes. To advance the understanding of how OAA mediates these changes, we compared the effects of OAA to malate, pyruvate, and glucose deprivation. We further examined how OAA affects levels of enzymes that facilitate its cytosolic metabolism, and found OAA increased the expression of malate dehydrogenase 1 (MDH1-cytosolic). We propose the following: OAA supports both glycolysis and respiration fluxes, shifts the cell redox balance toward a more oxidized state, and acts in an anaplerotic fashion. Abbreviations not defined in the text: MDH2, malate dehydrogenase 2 (mitochondrial).
authors.affiliation: Department of Neurology, University of Kansas Medical Center, Kansas City, Kansas, USA.|University of Kansas Alzheimer's Disease Center, University of Kansas Medical Center, Kansas City, Kansas, USA.
authors.forename: Heather M
authors.initials: HM
authors.lastname: Wilkins
authors.affiliation: University of Kansas Alzheimer's Disease Center, University of Kansas Medical Center, Kansas City, Kansas, USA.|Department of Molecular and Integrative Physiology, University of Kansas Medical Center, Kansas City, Kansas, USA.
authors.forename: Scott
authors.identifier: http://orcid.org/0000-0001-9001-4454
authors.initials: S
authors.lastname: Koppel
authors.affiliation: University of Kansas Alzheimer's Disease Center, University of Kansas Medical Center, Kansas City, Kansas, USA.
authors.forename: Steven M
authors.initials: SM
authors.lastname: Carl
authors.affiliation: University of Kansas Alzheimer's Disease Center, University of Kansas Medical Center, Kansas City, Kansas, USA.
authors.forename: Suruchi
authors.initials: S
authors.lastname: Ramanujan
authors.affiliation: University of Kansas Alzheimer's Disease Center, University of Kansas Medical Center, Kansas City, Kansas, USA.|Department of Molecular and Integrative Physiology, University of Kansas Medical Center, Kansas City, Kansas, USA.
authors.forename: Ian
authors.initials: I
authors.lastname: Weidling
authors.affiliation: University of Kansas Alzheimer's Disease Center, University of Kansas Medical Center, Kansas City, Kansas, USA.|Department of Pharmacology and Toxicology, University of Kansas, Lawrence, Kansas, USA.
authors.forename: Mary L
authors.initials: ML
authors.lastname: Michaelis
authors.affiliation: University of Kansas Alzheimer's Disease Center, University of Kansas Medical Center, Kansas City, Kansas, USA.|Department of Pharmacology and Toxicology, University of Kansas, Lawrence, Kansas, USA.
authors.forename: Elias K
authors.initials: EK
authors.lastname: Michaelis
authors.affiliation: Department of Neurology, University of Kansas Medical Center, Kansas City, Kansas, USA.|University of Kansas Alzheimer's Disease Center, University of Kansas Medical Center, Kansas City, Kansas, USA.|Department of Molecular and Integrative Physiology, University of Kansas Medical Center, Kansas City, Kansas, USA.|Department of Biochemistry and Molecular Biology, University of Kansas Medical Center, Kansas City, Kansas, USA.
authors.forename: Russell H
authors.initials: RH
authors.lastname: Swerdlow
mesh_terms: D000255:Adenosine Triphosphate / Q000378:metabolism; D002460:Cell Line; D045744:Cell Line, Tumor; D003600:Cytosol / Q000378:metabolism; D004734:Energy Metabolism / Q000187:drug effects; D005947:Glucose / Q000378:metabolism / Q000494:pharmacology; D006019:Glycolysis / Q000187:drug effects; D006801:Humans; D008291:Malate Dehydrogenase / Q000378:metabolism; D008293:Malates / Q000378:metabolism / Q000494:pharmacology; D008928:Mitochondria / Q000187:drug effects* / Q000378:metabolism; D009243:NAD / Q000378:metabolism; D009447:Neuroblastoma / Q000473:pathology; D009474:Neurons / Q000187:drug effects* / Q000378:metabolism; D062907:Oxaloacetic Acid / Q000494:pharmacology*; D010101:Oxygen Consumption; D019289:Pyruvic Acid / Q000378:metabolism / Q000494:pharmacology; D012333:RNA, Messenger / Q000096:biosynthesis
chemical_list: D008293:Malates; D012333:RNA, Messenger; D009243:NAD; D062907:Oxaloacetic Acid; C030298:malic acid; D019289:Pyruvic Acid; D000255:Adenosine Triphosphate; D008291:Malate Dehydrogenase; C030574:malate dehydrogenase (decarboxylating); D005947:Glucose
keywords: bioenergetics; glycolysis; mitochondria; oxaloacetate; respiration
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