Neuron specific metabolic adaptations following multi-day exposures to oxygen glucose deprivation

• Published in: Biochimica et biophysica acta Vol. 1802; no. 11; pp. 1095 - 1104
• Main Authors: Zeiger, Stephanie L.H., McKenzie, Jennifer R., Stankowski, Jeannette N., Martin, Jacob A., Cliffel, David E., McLaughlin, BethAnn
• Format: Journal Article
• Language: English
• Published: Netherlands Elsevier B.V 01.11.2010; Elsevier
• Subjects: Adaptation, Physiological; Animals; ATP; Blotting, Western; Caspase 3 - metabolism; Caspase activation; Cell Hypoxia; Cells, Cultured; Energy Metabolism - drug effects; Enzyme Activation - drug effects; Glucose - metabolism; Glucose - pharmacology; Heat shock protein 70; HSP70 Heat-Shock Proteins - metabolism; Immunohistochemistry; Microphysiometry; Neurons - cytology; Neurons - drug effects; Neurons - metabolism; Oxygen - metabolism; Oxygen - pharmacology; Oxygen glucose deprivation; Preconditioning; Protein carbonyl formation; Rats; Rats, Sprague-Dawley; Reactive oxygen species; Reactive Oxygen Species - metabolism; Stress, Physiological; Time Factors; PBS; Reactive oxygen species; HSP70; Microphysiometry; HSC70; OGD; TIA; LDH; BSA; Caspase activation; LOx; MAP2; ROS; NMDA; Heat shock protein 70; Oxygen glucose deprivation; Protein carbonyl formation; PBN; Preconditioning; ATP; oxygen glucose deprivation; microphysiometry; protein carbonyl formation; caspase activation; reactive oxygen species; heat shock protein 70
• ISSN: 0925-4439; 0006-3002; 1879-260X
• DOI: 10.1016/j.bbadis.2010.07.013

Prior exposure to sub toxic insults can induce a powerful endogenous neuroprotective program known as ischemic preconditioning. Current models typically rely on a single stress episode to induce neuroprotection whereas the clinical reality is that patients may experience multiple transient ischemic attacks (TIAs) prior to suffering a stroke. We sought to develop a neuron-enriched preconditioning model using multiple oxygen glucose deprivation (OGD) episodes to assess the endogenous protective mechanisms neurons implement at the metabolic and cellular level. We found that neurons exposed to a five minute period of glucose deprivation recovered oxygen utilization and lactate production using novel microphysiometry techniques. Using the non-toxic and energetically favorable five minute exposure, we developed a preconditioning paradigm where neurons are exposed to this brief OGD for three consecutive days. These cells experienced a 45% greater survival following an otherwise lethal event and exhibited a longer lasting window of protection in comparison to our previous in vitro preconditioning model using a single stress. As in other models, preconditioned cells exhibited mild caspase activation, an increase in oxidized proteins and a requirement for reactive oxygen species for neuroprotection. Heat shock protein 70 was upregulated during preconditioning, yet the majority of this protein was released extracellularly. We believe coupling this neuron-enriched multi-day model with microphysiometry will allow us to assess neuronal specific real-time metabolic adaptations necessary for preconditioning. ►We present a new model of preconditioning to capture the clinical reality of patients suffering multiple transient ischemic events prior to stroke. ►This series of multi-day sublethal stresses provides neuroprotection for up to 3 days. ►Real-time microphysiometry revealed rapid increases in aerobic respiratory activity in response to mild challenge. ►Neurons exposed to mild injury release large quantities of the neuroprotective chaperone HSP70. ►The metabolic and biochemical features of this model may allow us to determine real-time adaptation to ischemic stress.