title: Ethanol preconditioning of rat cerebellar cultures targets NMDA receptors to the synapse and enhances peroxiredoxin 2 expression.
abstract: Epidemiological studies indicate that light-moderate alcohol (ethanol) consumers tend to have reduced risks of cognitive impairment and progression to dementia during aging. Exploring possible mechanisms, we previously found that moderate ethanol preconditioning (MEP, 20-30mM) of rat brain cultures for several days instigated neuroprotection against β-amyloid peptides. Our biochemical evidence implicated the NMDA receptor (NMDAR) as a potential neuroprotective "sensor", specifically via synaptic NMDAR signaling. It remains unclear how ethanol modulates the receptor and its downstream targets to engender neuroprotection. Here we confirm with deconvolution microscopy that MEP of rat mixed cerebellar cultures robustly increases synaptic NMDAR localization. Phospho-activation of the non-receptor tyrosine kinases Src and Pyk2, known to be linked to synaptic NMDAR, is also demonstrated. Additionally, the preconditioning enhances levels of an antioxidant protein, peroxiredoxin 2 (Prx2), reported to be downstream of synaptic NMDAR signaling, and NMDAR antagonism with memantine (earlier found to abrogate MEP neuroprotection) blocks the Prx2 elevations. To further link Prx2 with antioxidant-based neuroprotection, we circumvented the ethanol preconditioning-NMDAR pathway by pharmacologically increasing Prx2 with the naturally-occurring cruciferous compound, 3H-1,2-dithiole-3-thione (D3T). Thus, D3T pretreatment elevated Prx2 expression to a similar extent as MEP, while concomitantly preventing β-amyloid neurotoxicity; D3T also protected the cultures from hydrogen peroxide toxicity. The findings support a mechanism that couples synaptic NMDAR signaling, Prx2 expression and augmented antioxidant defenses in ethanol preconditioning-induced neuroprotection. That this mechanism can be emulated by a cruciferous vegetable constituent suggests that such naturally-occurring "neutraceuticals" may be useful in therapy for oxidative stress-related dementias.
authors.affiliation: Department of Molecular Pharmacology & Therapeutics, Loyola University Chicago, Stritch School of Medicine, Maywood, IL 60153, United States.
authors.forename: Robert M
authors.initials: RM
authors.lastname: Mitchell
authors.affiliation: Department of Molecular Pharmacology & Therapeutics, Loyola University Chicago, Stritch School of Medicine, Maywood, IL 60153, United States.
authors.forename: Nuzhath
authors.initials: N
authors.lastname: Tajuddin
authors.affiliation: Department of Cell & Molecular Physiology, Loyola University Chicago, Stritch School of Medicine, Maywood, IL 60153, United States.
authors.forename: Edward M
authors.initials: EM
authors.lastname: Campbell
authors.affiliation: Department of Molecular Pharmacology & Therapeutics, Loyola University Chicago, Stritch School of Medicine, Maywood, IL 60153, United States.
authors.forename: Edward J
authors.initials: EJ
authors.lastname: Neafsey
authors.affiliation: Department of Molecular Pharmacology & Therapeutics, Loyola University Chicago, Stritch School of Medicine, Maywood, IL 60153, United States. Electronic address: mcollin@luc.edu.
authors.forename: Michael A
authors.initials: MA
authors.lastname: Collins
mesh_terms: D000818:Animals; D002478:Cells, Cultured; D002531:Cerebellum / Q000166:cytology / Q000187:drug effects* / Q000378:metabolism*; D000431:Ethanol / Q000494:pharmacology*; D051418:Focal Adhesion Kinase 2 / Q000378:metabolism; D054464:Peroxiredoxins / Q000378:metabolism*; D010766:Phosphorylation / Q000187:drug effects; D051381:Rats; D017207:Rats, Sprague-Dawley; D016194:Receptors, N-Methyl-D-Aspartate / Q000378:metabolism*; D013569:Synapses / Q000187:drug effects* / Q000378:metabolism*; D019061:src-Family Kinases / Q000378:metabolism
chemical_list: D016194:Receptors, N-Methyl-D-Aspartate; D000431:Ethanol; D054464:Peroxiredoxins; D051418:Focal Adhesion Kinase 2; D019061:src-Family Kinases
keywords: Alcohol; Deconvolution microscopy; NMDA receptor; Neuroprotection; Peroxiredoxin 2; Preconditioning