title: Aralar mRNA and protein levels in neurons and astrocytes freshly isolated from young and adult mouse brain and in maturing cultured astrocytes.
abstract: Intense glucose-based energy metabolism and glutamate synthesis by astrocytes require malate-aspartate-shuttle (MAS) activity to regenerate NAD⁺ from NADH formed during glycolysis, since brain lacks significant glycerophosphate shuttle activity. Aralar is a necessary aspartate/glutamate exchanger for MAS function in brain. Based on cytochemical immunoassays the absence of aralar in adult astrocytes was repeatedly reported. This would mean that adult astrocytes must regenerate NAD⁺ by producing lactate from pyruvate, eliminating its use by oxidative and biosynthetic pathways. We alternatively used astrocytes and neurons from adult brain, freshly isolated by fluorescence-activated cell sorting, to determine aralar protein by a specific antibody and its mRNA by real-time PCR. Both protein and mRNA expressions were identical in adult neurons and astrocytes and similar to whole brain levels. The same level of aralar expression was reached in well-differentiated astrocyte cultures, but not until late development, coinciding with the late-maturing brain capability for glutamate formation and degradation.
authors.affiliation: Department of Clinical Pharmacology, China Medical University, Shenyang, PR China.
authors.forename: Baoman
authors.initials: B
authors.lastname: Li
authors.forename: Leif
authors.initials: L
authors.lastname: Hertz
authors.forename: Liang
authors.initials: L
authors.lastname: Peng
mesh_terms: D000375:Aging / Q000378:metabolism*; D000818:Animals; D001224:Aspartic Acid / Q000378:metabolism; D001253:Astrocytes / Q000378:metabolism*; D001921:Brain / Q000166:cytology / Q000254:growth & development* / Q000378:metabolism; D002469:Cell Separation / Q000379:methods; D002478:Cells, Cultured / Q000378:metabolism; D016922:Cellular Senescence; D003593:Cytoplasm / Q000378:metabolism; D004734:Energy Metabolism; D005260:Female; D018698:Glutamic Acid / Q000378:metabolism; D019344:Lactic Acid / Q000378:metabolism; D008297:Male; D051379:Mice; D008822:Mice, Transgenic; D008928:Mitochondria / Q000378:metabolism; D033681:Mitochondrial Membrane Transport Proteins / Q000235:genetics / Q000378:metabolism*; D009243:NAD / Q000378:metabolism; D009419:Nerve Tissue Proteins / Q000235:genetics / Q000378:metabolism*; D009474:Neurons / Q000378:metabolism*; D010084:Oxidation-Reduction; D061251:Primary Cell Culture; D019289:Pyruvic Acid / Q000378:metabolism; D012333:RNA, Messenger / Q000096:biosynthesis; D060888:Real-Time Polymerase Chain Reaction
chemical_list: D033681:Mitochondrial Membrane Transport Proteins; D009419:Nerve Tissue Proteins; D012333:RNA, Messenger; C491956:Slc25a12 protein, mouse; D009243:NAD; D001224:Aspartic Acid; D019344:Lactic Acid; D018698:Glutamic Acid; D019289:Pyruvic Acid