Pretreatment with apoaequorin protects hippocampal CA1 neurons from oxygen-glucose deprivation

• Published in: PloS one 2013-11, Vol.8 (11), p.e79002-e79002
• Main Authors: Detert, Julia A, Adams, Erin L, Lescher, Jacob D, Lyons, Jeri-Anne, Moyer, Jr, James R
• Format: Article
• Language: English
• Subjects: Aequorin - pharmacology; Aging; Animals; Apoproteins - pharmacology; Apoptosis; Brain; Brain Ischemia - drug therapy; Brain Ischemia - metabolism; Brain Ischemia - pathology; Brain research; Brain slice preparation; CA1 Region, Hippocampal - metabolism; CA1 Region, Hippocampal - pathology; Calcium; Calcium (intracellular); Calcium binding proteins; Calcium buffering; Calcium influx; Calcium-binding protein; Cascades; Cell death; Cell Death - drug effects; Clinical trials; Cytokines; Deprivation; Excitotoxicity; Gene expression; Glucose; Glucose - metabolism; Hippocampus; Humans; Hypotheses; Infusion; Ischemia; Mortality; Neurons; Neurons - metabolism; Neurons - pathology; Neuroprotection; Oxygen; Oxygen - metabolism; Oxygen Consumption - drug effects; Polymerase chain reaction; Pretreatment; Protein binding; Proteins; Rats; Recombinant Proteins - pharmacology; Renilla-luciferin 2-monooxygenase; Rodents; Signaling; Stroke; Time dependence; TNF inhibitors; Tumor necrosis factor-TNF
• ISSN: 1932-6203; 1932-6203
• DOI: 10.1371/journal.pone.0079002

Ischemic stroke affects ∼795,000 people each year in the U.S., which results in an estimated annual cost of $73.7 billion. Calcium is pivotal in a variety of neuronal signaling cascades, however, during ischemia, excess calcium influx can trigger excitotoxic cell death. Calcium binding proteins help neurons regulate/buffer intracellular calcium levels during ischemia. Aequorin is a calcium binding protein isolated from the jellyfish Aequorea victoria, and has been used for years as a calcium indicator, but little is known about its neuroprotective properties. The present study used an in vitro rat brain slice preparation to test the hypothesis that an intra-hippocampal infusion of apoaequorin (the calcium binding component of aequorin) protects neurons from ischemic cell death. Bilaterally cannulated rats received an apoaequorin infusion in one hemisphere and vehicle control in the other. Hippocampal slices were then prepared and subjected to 5 minutes of oxygen-glucose deprivation (OGD), and cell death was assayed by trypan blue exclusion. Apoaequorin dose-dependently protected neurons from OGD--doses of 1% and 4% (but not 0.4%) significantly decreased the number of trypan blue-labeled neurons. This effect was also time dependent, lasting up to 48 hours. This time dependent effect was paralleled by changes in cytokine and chemokine expression, indicating that apoaequorin may protect neurons via a neuroimmunomodulatory mechanism. These data support the hypothesis that pretreatment with apoaequorin protects neurons against ischemic cell death, and may be an effective neurotherapeutic.