title: Wld(S) reduces paraquat-induced cytotoxicity via SIRT1 in non-neuronal cells by attenuating the depletion of NAD.
abstract: Wld(S) is a fusion protein with NAD synthesis activity, and has been reported to protect axonal and synaptic compartments of neurons from various mechanical, genetic and chemical insults. However, whether Wld(S) can protect non-neuronal cells against toxic chemicals is largely unknown. Here we found that Wld(S) significantly reduced the cytotoxicity of bipyridylium herbicides paraquat and diquat in mouse embryonic fibroblasts, but had no effect on the cytotoxicity induced by chromium (VI), hydrogen peroxide, etoposide, tunicamycin or brefeldin A. Wld(S) also slowed down the death of mice induced by intraperitoneal injection of paraquat. Further studies demonstrated that Wld(S) markedly attenuated mitochondrial injury including disruption of mitochondrial membrane potential, structural damage and decline of ATP induced by paraquat. Disruption of the NAD synthesis activity of Wld(S) by an H112A or F116S point mutation resulted in loss of its protective function against paraquat-induced cell death. Furthermore, Wld(S) delayed the decrease of intracellular NAD levels induced by paraquat. Similarly, treatment with NAD or its precursor nicotinamide mononucleotide attenuated paraquat-induced cytotoxicity and decline of ATP and NAD levels. In addition, we showed that SIRT1 was required for both exogenous NAD and Wld(S)-mediated cellular protection against paraquat. These findings suggest that NAD and SIRT1 mediate the protective function of Wld(S) against the cytotoxicity induced by paraquat, which provides new clues for the mechanisms underlying the protective function of Wld(S) in both neuronal and non-neuronal cells, and implies that attenuation of NAD depletion may be effective to alleviate paraquat poisoning.
authors.affiliation: Key Laboratory of Nutrition and Metabolism, Institute for Nutritional Sciences, Graduate School of the Chinese Academy of Sciences, Chinese Academy of Sciences, Shanghai, China.
authors.forename: Qiujing
authors.initials: Q
authors.lastname: Yu
authors.forename: Ting
authors.initials: T
authors.lastname: Wang
authors.forename: Xuexia
authors.initials: X
authors.lastname: Zhou
authors.forename: Jingxia
authors.initials: J
authors.lastname: Wu
authors.forename: Xingmiao
authors.initials: X
authors.lastname: Chen
authors.forename: Yang
authors.initials: Y
authors.lastname: Liu
authors.forename: Dongmei
authors.initials: D
authors.lastname: Wu
authors.forename: Qiwei
authors.initials: Q
authors.lastname: Zhai
mesh_terms: D000255:Adenosine Triphosphate / Q000378:metabolism; D000818:Animals; D015153:Blotting, Western; D002470:Cell Survival / Q000187:drug effects; D002478:Cells, Cultured; D004622:Embryo, Mammalian / Q000166:cytology; D005347:Fibroblasts / Q000166:cytology / Q000187:drug effects / Q000378:metabolism; D006540:Herbicides / Q000008:administration & dosage / Q000633:toxicity; D006861:Hydrogen Peroxide / Q000633:toxicity; D007274:Injections, Intraperitoneal; D008297:Male; D053078:Membrane Potential, Mitochondrial / Q000187:drug effects; D051379:Mice; D008810:Mice, Inbred C57BL; D018345:Mice, Knockout; D008854:Microscopy, Electron; D008930:Mitochondria, Liver / Q000187:drug effects / Q000502:physiology / Q000648:ultrastructure; D009154:Mutation; D009243:NAD / Q000378:metabolism* / Q000494:pharmacology; D009419:Nerve Tissue Proteins / Q000235:genetics / Q000378:metabolism*; D009537:Nicotinamide Mononucleotide / Q000494:pharmacology; D016877:Oxidants / Q000633:toxicity; D010269:Paraquat / Q000008:administration & dosage / Q000633:toxicity*; D017382:Reactive Oxygen Species / Q000378:metabolism; D056564:Sirtuin 1 / Q000235:genetics / Q000378:metabolism*
chemical_list: D006540:Herbicides; D009419:Nerve Tissue Proteins; D016877:Oxidants; D017382:Reactive Oxygen Species; C442580:Wld protein, mouse; D009243:NAD; D009537:Nicotinamide Mononucleotide; D000255:Adenosine Triphosphate; D006861:Hydrogen Peroxide; C470545:Sirt1 protein, mouse; D056564:Sirtuin 1; D010269:Paraquat