title: Amyloid beta resistance in nerve cell lines is mediated by the Warburg effect.
abstract: Amyloid beta (Aβ) peptide accumulation in the brains of patients with Alzheimer's disease (AD) is closely associated with increased nerve cell death. However, many cells survive and it is important to understand the mechanisms involved in this survival response. Recent studies have shown that an anti-apoptotic mechanism in cancer cells is mediated by aerobic glycolysis, also known as the Warburg effect. One of the major regulators of aerobic glycolysis is pyruvate dehydrogenase kinase (PDK), an enzyme which represses mitochondrial respiration and forces the cell to rely heavily on glycolysis, even in the presence of oxygen. Recent neuroimaging studies have shown that the spatial distribution of aerobic glycolysis in the brains of AD patients strongly correlates with Aβ deposition. Interestingly, clonal nerve cell lines selected for resistance to Aβ exhibit increased glycolysis as a result of activation of the transcription factor hypoxia inducible factor 1. Here we show that Aβ resistant nerve cell lines upregulate Warburg effect enzymes in a manner reminiscent of cancer cells. In particular, Aβ resistant nerve cell lines showed elevated PDK1 expression in addition to an increase in lactate dehydrogenase A (LDHA) activity and lactate production when compared to control cells. In addition, mitochondrial derived reactive oxygen species (ROS) were markedly diminished in resistant but not sensitive cells. Chemically or genetically inhibiting LDHA or PDK1 re-sensitized resistant cells to Aβ toxicity. These findings suggest that the Warburg effect may contribute to apoptotic-resistance mechanisms in the surviving neurons of the AD brain. Loss of the adaptive advantage afforded by aerobic glycolysis may exacerbate the pathophysiological processes associated with AD.
authors.affiliation: Department of Biology, The University of Western Ontario, London, Ontario, Canada.
authors.forename: Jordan T
authors.initials: JT
authors.lastname: Newington
authors.forename: Andrea
authors.initials: A
authors.lastname: Pitts
authors.forename: Andrew
authors.initials: A
authors.lastname: Chien
authors.forename: Robert
authors.initials: R
authors.lastname: Arseneault
authors.forename: David
authors.initials: D
authors.lastname: Schubert
authors.forename: Robert C
authors.initials: RC
authors.lastname: Cumming
mesh_terms: D016229:Amyloid beta-Peptides / Q000633:toxicity*; D000818:Animals; D006019:Glycolysis / Q000187:drug effects*; D007770:L-Lactate Dehydrogenase / Q000037:antagonists & inhibitors; D019344:Lactic Acid / Q000096:biosynthesis; D008928:Mitochondria / Q000187:drug effects / Q000378:metabolism; D008954:Models, Biological; D009474:Neurons / Q000187:drug effects* / Q000378:metabolism*; D016716:PC12 Cells; D017346:Protein Serine-Threonine Kinases / Q000037:antagonists & inhibitors / Q000378:metabolism; D000081382:Pyruvate Dehydrogenase Acetyl-Transferring Kinase; D051381:Rats; D017382:Reactive Oxygen Species / Q000378:metabolism
chemical_list: D016229:Amyloid beta-Peptides; C000631434:Pdk1 protein, rat; D000081382:Pyruvate Dehydrogenase Acetyl-Transferring Kinase; D017382:Reactive Oxygen Species; D019344:Lactic Acid; D007770:L-Lactate Dehydrogenase; D017346:Protein Serine-Threonine Kinases