title: Urate oxidase knockdown decreases oxidative stress in a murine hepatic cell line.
abstract: Humans, birds, and some primates do not express the uric acid degrading enzyme urate oxidase (UOX) and, as a result, have plasma uric acid concentrations higher than UOX expressing animals. Although high uric acid concentrations are suggested to increase the antioxidant defense system and provide a health advantage to animals without UOX, knockout mice lacking UOX develop pathological complications including gout and kidney failure. As an alternative to the knockout model, RNA interference was used to decrease UOX expression using stable transfection in a mouse hepatic cell line (ATCC, FL83B). Urate oxidase mRNA was reduced 66% (p < 0.05) compared to wild type, as measured by real time RT-PCR. To determine if UOX knockdown resulted in enhanced protection against oxidative stress, cells were challenged with hexavalent chromium (Cr(VI)) or 3-morpholinosydnonimine hydrochloride (SIN-1). Compared to wild type, cells with UOX knockdown exhibited a 37.2 +/- 3.5% reduction (p < 0.05) in the electron spin resonance (ESR) signal after being exposed to Cr(VI) and displayed less DNA fragmentation (p < 0.05) following SIN-1 treatment. Cell viability decreased in wild type cells (p < 0.05), but not cells with UOX knockdown, after treatment with SIN-1. These results are consistent with an increased intracellular uric acid concentration and an increased defense against oxidative stress.
authors.affiliation: Division of Animal and Nutritional Sciences, West Virginia University, Morgantown, WV 26506, USA.
authors.forename: Beth M
authors.initials: BM
authors.lastname: Cleveland
authors.forename: Stephen S
authors.initials: SS
authors.lastname: Leonard
authors.forename: Hillar
authors.initials: H
authors.lastname: Klandorf
authors.forename: Kenneth P
authors.initials: KP
authors.lastname: Blemings
mesh_terms: D000818:Animals; D002460:Cell Line; D002470:Cell Survival; D002857:Chromium / Q000633:toxicity; D022781:Hepatocytes / Q000378:metabolism*; D051379:Mice; D008981:Molsidomine / Q000031:analogs & derivatives / Q000633:toxicity; D018384:Oxidative Stress; D034622:RNA Interference; D012333:RNA, Messenger / Q000378:metabolism; D014503:Urate Oxidase / Q000235:genetics / Q000378:metabolism*
chemical_list: D012333:RNA, Messenger; D002857:Chromium; C074702:chromium hexavalent ion; C002385:linsidomine; D008981:Molsidomine; D014503:Urate Oxidase