title: Hydrogen peroxide responsive miR153 targets Nrf2/ARE cytoprotection in paraquat induced dopaminergic neurotoxicity.
abstract: Epidemiological and animal studies suggest that environmental toxins including paraquat (PQ) increase the risk of developing Parkinson's disease (PD) by damaging nigrostriatal dopaminergic neurons. We previously showed that overexpression of a group of microRNAs (miRs) affects the antioxidant promoting factor, Nrf2 and related glutathione-redox homeostasis in SH-SY5Y dopaminergic neurons. Although, dysregulation of redox balance by PQ is well documented, the role for miRs and their impact have not been elucidated. In the current study we investigated whether PQ impairs Nrf2 and its related cytoprotective machinery by misexpression of specific fine tune miRs in SH-SY5Y neurons. Real time PCR analysis revealed that PQ significantly (p<0.05) increased the expression of brain enriched miR153 with an associated decrease in Nrf2 and its function as revealed by decrease in 4× ARE activity and expression of GCLC and NQO1. Also, PQ and H2O2-induced decrease in Nrf2 3' UTR activity was restored on miR153 site mutation suggesting a 3' UTR interacting role. Overexpression of either anti-miR153 or Nrf2 cDNA devoid of 3' UTR prevented PQ and H2O2-induced loss in Nrf2 activity confirming that PQ could cause miR153 to bind to and target Nrf2 3' UTR thereby weakening the cellular antioxidant defense. Adenovirus mediated overexpression of cytoplasmic catalase (Ad cCAT) confirmed that PQ induced miR153 is hydrogen peroxide (H2O2) dependent. In addition, Ad cCAT significantly (p<0.05) negated the PQ induced dysregulation of Nrf2 and function along with minimizing ROS, caspase 3/7 activation and neuronal death. Altogether, these results suggest a critical role for oxidant mediated miR153-Nrf2/ARE pathway interaction in paraquat neurotoxicity. This novel finding facilitates the understanding of molecular mechanisms and to develop appropriate management alternatives to counteract PQ-induced neuronal pathogenesis.
authors.affiliation: Department of Pharmacology and Neuroscience, Texas Tech University Health Sciences Center, Lubbock, TX 79430 USA; South Plains Alcohol and Addiction Research Center, Texas Tech University Health Sciences Center, Lubbock, TX, USA. Electronic address: madhu.narasimhan@ttuhsc.edu.
authors.forename: Madhusudhanan
authors.initials: M
authors.lastname: Narasimhan
authors.affiliation: Department of Pharmacology and Neuroscience, Texas Tech University Health Sciences Center, Lubbock, TX 79430 USA.
authors.forename: Amanjot Kaur
authors.initials: AK
authors.lastname: Riar
authors.affiliation: Department of Pharmacology and Neuroscience, Texas Tech University Health Sciences Center, Lubbock, TX 79430 USA.
authors.forename: Mary Latha
authors.initials: ML
authors.lastname: Rathinam
authors.affiliation: Department of Pharmacology and Neuroscience, Texas Tech University Health Sciences Center, Lubbock, TX 79430 USA.
authors.forename: Dhanashree
authors.initials: D
authors.lastname: Vedpathak
authors.affiliation: Department of Pharmacology and Neuroscience, Texas Tech University Health Sciences Center, Lubbock, TX 79430 USA; South Plains Alcohol and Addiction Research Center, Texas Tech University Health Sciences Center, Lubbock, TX, USA.
authors.forename: George
authors.initials: G
authors.lastname: Henderson
authors.affiliation: Department of Pharmacology and Neuroscience, Texas Tech University Health Sciences Center, Lubbock, TX 79430 USA; South Plains Alcohol and Addiction Research Center, Texas Tech University Health Sciences Center, Lubbock, TX, USA. Electronic address: lenin.mahimainathan@ttuhsc.edu.
authors.forename: Lenin
authors.initials: L
authors.lastname: Mahimainathan
mesh_terms: D020413:3' Untranslated Regions; D061745:Antioxidant Response Elements / Q000187:drug effects*; D001665:Binding Sites; D053148:Caspase 3 / Q000378:metabolism; D053179:Caspase 7 / Q000378:metabolism; D002374:Catalase / Q000235:genetics / Q000378:metabolism; D016923:Cell Death / Q000187:drug effects; D045744:Cell Line, Tumor; D019610:Cytoprotection; D059290:Dopaminergic Neurons / Q000187:drug effects* / Q000378:metabolism / Q000473:pathology; D005786:Gene Expression Regulation; D006801:Humans; D006861:Hydrogen Peroxide / Q000633:toxicity*; D035683:MicroRNAs / Q000235:genetics / Q000378:metabolism*; D051267:NF-E2-Related Factor 2 / Q000235:genetics / Q000378:metabolism*; D020258:Neurotoxicity Syndromes / Q000209:etiology* / Q000235:genetics / Q000378:metabolism / Q000473:pathology; D010084:Oxidation-Reduction; D010269:Paraquat / Q000633:toxicity*; D017382:Reactive Oxygen Species / Q000378:metabolism; D014162:Transfection
chemical_list: D020413:3' Untranslated Regions; C556500:MIRN153 microRNA, human; D035683:MicroRNAs; D051267:NF-E2-Related Factor 2; C495635:NFE2L2 protein, human; D017382:Reactive Oxygen Species; D006861:Hydrogen Peroxide; D002374:Catalase; C505407:CASP3 protein, human; C505520:CASP7 protein, human; D053148:Caspase 3; D053179:Caspase 7; D010269:Paraquat
keywords: H(2)O(2); Neurotoxicity; Nrf2; Paraquat; miR153