title: Nitroxide antioxidant as a potential strategy to attenuate the oxidative/nitrosative stress induced by hydrogen peroxide plus nitric oxide in cultured neurons.
abstract: Oxidative/nitrosative stress contributes to the etiology of the neurological disorders, including ischemic stroke and chronic neurodegeneration. Neurotoxic modifications mediated by reactive oxygen species (ROS) or reactive nitrogen species (RNS) are closely associated with the destruction of key macromolecules and inactivation of antioxidant enzymes, which compromises antioxidant defenses. Approaches to expel ROS/RNS and alleviate toxic oxidative/nitrosative stress in neurons have not completely been defined. Here, we aimed to evaluate the efficacy of various antioxidants that serve as the neuroprotectors under a toxic stress created by ROS plus nitric oxide (NO). Sublytic concentrations of hydrogen peroxide (H2O2) plus NO donor S-nitroso-N-acetyl-D, L-penicillamine (SNAP) enabled to induce a toxic oxidative/nitrosative stress through activating both p38 MAPK and p53 cascades, and cause DNA damage and protein tyrosine nitration in primary neuronal cultures. After comparing six antioxidants, including superoxide dimutase (SOD), catalase, 2,2,6,6-tetramethyl-1-piperidinoxyl (TEMPO), N-acetylcysteine, dimethylthiourea, and uric acid, TEMPO was the superior antioxidant that comprehensively and efficaciously decreased H2O2 plus SNAP-evoked activation of stress cascades of p38 MAPK and p53, production of NO, ROS, and peroxynitrite, double-strand breaks of DNA, and nitration of protein tyrosine residues. SOD increased the peroxynitrite formation and was unable to reduce the level of protein nitration. All antioxidants tested, except SOD, effectively reduced neuronal damage and DNA breakage caused by the toxic H2O2/SNAP combination. In conclusion, these results suggest that TEMPO ensures excellent ROS/RNS clearance and stress-signaling inhibition, thus effectively rescuing neurons from ROS/H2O2 plus NO/SNAP-induced insult. This study reveals a potential strategy for nitroxide antioxidants as a therapeutic agent against oxidative/nitrosative neurotoxicity.
authors.affiliation: Department of Nursing, Hsin-Sheng College of Medical Care and Management, Taoyuan, Taiwan, ROC. Electronic address: chingtien1213@gmail.com.
authors.forename: Ching-Tien
authors.initials: CT
authors.lastname: Lee
authors.affiliation: Department of Neurology & Master's Program, School of Medicine, College of Medicine, Kaohsiung Medical University, Kaohsiung, Taiwan, ROC. Electronic address: d2316l@gmail.com.
authors.forename: Liang-En
authors.initials: LE
authors.lastname: Yu
authors.affiliation: Department of Neurology & Master's Program, School of Medicine, College of Medicine, Kaohsiung Medical University, Kaohsiung, Taiwan, ROC; Graduate Institute of Medicine, College of Medicine, Kaohsiung Medical University, Kaohsiung, Taiwan, ROC. Electronic address: jizyuhwang@cc.kmu.edu.tw.
authors.forename: Jiz-Yuh
authors.initials: JY
authors.lastname: Wang
mesh_terms: D000111:Acetylcysteine / Q000494:pharmacology; D000818:Animals; D000975:Antioxidants / Q000494:pharmacology*; D002374:Catalase / Q000494:pharmacology; D003497:Cyclic N-Oxides / Q000494:pharmacology; D006861:Hydrogen Peroxide / Q000494:pharmacology*; D007770:L-Lactate Dehydrogenase / Q000378:metabolism; D009474:Neurons / Q000187:drug effects* / Q000378:metabolism; D009569:Nitric Oxide / Q000378:metabolism*; D020030:Nitric Oxide Donors / Q000494:pharmacology; D009573:Nitrites / Q000378:metabolism; D018384:Oxidative Stress / Q000187:drug effects*; D030421:Peroxynitrous Acid / Q000378:metabolism; D051381:Rats; D017207:Rats, Sprague-Dawley; D026361:Reactive Nitrogen Species / Q000378:metabolism*; D017382:Reactive Oxygen Species / Q000378:metabolism*; D026423:S-Nitroso-N-Acetylpenicillamine / Q000494:pharmacology; D013482:Superoxide Dismutase / Q000494:pharmacology; D013890:Thiourea / Q000031:analogs & derivatives / Q000494:pharmacology; D014527:Uric Acid / Q000494:pharmacology
chemical_list: D000975:Antioxidants; D003497:Cyclic N-Oxides; D020030:Nitric Oxide Donors; D009573:Nitrites; D026361:Reactive Nitrogen Species; D017382:Reactive Oxygen Species; D030421:Peroxynitrous Acid; D014527:Uric Acid; D009569:Nitric Oxide; D026423:S-Nitroso-N-Acetylpenicillamine; C038983:1,3-dimethylthiourea; D006861:Hydrogen Peroxide; D007770:L-Lactate Dehydrogenase; D002374:Catalase; D013482:Superoxide Dismutase; D013890:Thiourea; C003959:TEMPO; D000111:Acetylcysteine
keywords: Antioxidant; H(2)O(2); Neuron; Nitric oxide; Oxidative/nitrosative stress; SNAP