title: Neurite transection produces cytosolic oxidation, which enhances plasmalemmal repair.
abstract: To survive, cells must rapidly repair (seal) plasmalemmal damage. Cytosolic oxidation has been shown to increase cell survival in some cases and produce cell death in other protocols. An antioxidant (melatonin; Mel) has been reported to decrease the probability of sealing plasmalemmal damage. Here we report that plasmalemmal damage produces cytosolic oxidation, as assayed by methylene blue (MB) color change in rat B104 hippocampal cells. Plasmalemmal sealing is affected by duration of Ca²⁺ deprivation and length of exposure to, and concentration of, oxidizing agents such as H₂O₂ and thimerosal (TH). Cytosolic oxidation by 10 μM to 50 mM H₂O₂ or 100 μM to 2 mM TH increases the probability of Ca²⁺-dependent plasmalemmal sealing, whereas higher concentrations of H₂O₂ decrease sealing probability and also damage uninjured cells. We also show that antioxidants (Mel, MB) or reducing agents (dithiothreitol) decrease sealing. Proteins, such as protein kinase A, SNAP-25, synaptobrevin, and N-ethylmaleimide-sensitive factor (previously reported to enhance sealing in other pathways), also enhance sealing in this oxidation pathway. In brief, our data show that plasmalemmal damage produces cytosolic oxidation that increases the probability of plasmalemmal sealing, which is strongly correlated with cell survival in other studies. Our results may provide new insights into the etiology and treatment of oxidation-dependent neurodegenerative disorders, such as Parkinson's, Huntington's, and Alzheimer's diseases.
authors.affiliation: Institute for Cellular and Molecular Biology, University of Texas at Austin, Austin, Texas, USA.
authors.forename: C S
authors.initials: CS
authors.lastname: Spaeth
authors.forename: J D
authors.initials: JD
authors.lastname: Fan
authors.forename: E B
authors.initials: EB
authors.lastname: Spaeth
authors.forename: T
authors.initials: T
authors.lastname: Robison
authors.forename: R W
authors.initials: RW
authors.lastname: Wilcott
authors.forename: G D
authors.initials: GD
authors.lastname: Bittner
mesh_terms: D000818:Animals; D000975:Antioxidants / Q000494:pharmacology; D019771:Axotomy; D002118:Calcium / Q000378:metabolism; D045744:Cell Line, Tumor; D002462:Cell Membrane / Q000187:drug effects / Q000502:physiology*; D003600:Cytosol / Q000187:drug effects / Q000502:physiology*; D004305:Dose-Response Relationship, Drug; D004347:Drug Interactions; D006861:Hydrogen Peroxide / Q000494:pharmacology; D016501:Neurites / Q000187:drug effects / Q000378:metabolism*; D009447:Neuroblastoma / Q000473:pathology; D016877:Oxidants / Q000494:pharmacology; D010084:Oxidation-Reduction / Q000187:drug effects; D047428:Protein Kinase Inhibitors / Q000494:pharmacology; D051381:Rats; D013997:Time Factors; D014945:Wound Healing / Q000187:drug effects / Q000502:physiology*
chemical_list: D000975:Antioxidants; D016877:Oxidants; D047428:Protein Kinase Inhibitors; D006861:Hydrogen Peroxide; D002118:Calcium