title: RNA interference-mediated inhibition of brain-derived neurotrophic factor expression increases cocaine's cytotoxicity in cultured cells.
abstract: Previous studies showed that cocaine exposure decreased brain-derived neurotrophic factor (BDNF) function and resulted in neuronal cell death. To investigate a role of BDNF in cocaine's cytotoxicity, an RNA interference (RNAi) approach was used. Transfection of neuroblastoma SK-N-AS cells or primary rat hippocampal neurons with the small double-stranded interfering RNA (siRNA) targeting BDNF mRNA, but not the scrambled siRNA, resulted in reductions in levels of BDNF mRNA and proteins by more than 70% in the transfected cells as compared with the control group, suggesting an RNAi-mediated, sequence-specific gene silencing. The results also showed that cocaine-induced cytotoxicity, assessed by the MTT (3-[4,5-dimethylthiazol-2-yl]-2,5-diphenyltetrazodium bromide) assay, was more pronounced in the cells transfected with the siRNA than in the cells transfected with the scrambled siRNA or in the cells treated with Lipofectamine 2000 alone (the control group), suggesting that inhibition of BDNF expression enhances cocaine's cytotoxicity. Together with previous studies showing that cocaine suppresses BDNF expression, the present data suggest that the drug-induced reduction of BDNF productions may make neurons more vulnerable to cocaine's toxic effects and precipitate cocaine-induced central nervous system damages.
authors.affiliation: Department of Cancer Biology and Pharmacology, University of Illinois College of Medicine at Peoria, Peoria, IL 61656, USA. qsy@uic.edu
authors.forename: Qing-Shan
authors.initials: QS
authors.lastname: Yan
authors.forename: Mei-Jinag
authors.initials: MJ
authors.lastname: Feng
authors.forename: Shu-E
authors.initials: SE
authors.lastname: Yan
mesh_terms: D000818:Animals; D001921:Brain / Q000187:drug effects* / Q000378:metabolism / Q000503:physiopathology; D019208:Brain-Derived Neurotrophic Factor / Q000037:antagonists & inhibitors / Q000235:genetics / Q000378:metabolism*; D016923:Cell Death / Q000187:drug effects / Q000235:genetics; D045744:Cell Line, Tumor; D002478:Cells, Cultured; D003042:Cocaine / Q000633:toxicity*; D019970:Cocaine-Related Disorders / Q000235:genetics / Q000378:metabolism* / Q000503:physiopathology; D018765:Dopamine Uptake Inhibitors / Q000633:toxicity; D015536:Down-Regulation / Q000235:genetics; D005786:Gene Expression Regulation / Q000187:drug effects / Q000235:genetics; D006801:Humans; D009474:Neurons / Q000187:drug effects* / Q000378:metabolism / Q000473:pathology; D034622:RNA Interference; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D034741:RNA, Small Interfering / Q000235:genetics; D051381:Rats; D017207:Rats, Sprague-Dawley; D013778:Tetrazolium Salts; D013844:Thiazoles; D014162:Transfection
chemical_list: D019208:Brain-Derived Neurotrophic Factor; D018765:Dopamine Uptake Inhibitors; D012333:RNA, Messenger; D034741:RNA, Small Interfering; D013778:Tetrazolium Salts; D013844:Thiazoles; C022616:thiazolyl blue; D003042:Cocaine