title: Role of p66shc in renal toxicity of oleic acid.
abstract: OBJECTIVE
  Adult and childhood obesity is an independent risk factor in development of chronic kidney disease (CKD) and its progression to end-stage kidney disease. Pathologic consequences of obesity include non-esterified fatty acid-induced oxidative stress and consequent injury. Since the serine36-phosphorylated p66shc is a newly recognized mediator of oxidative stress and kidney injury, we studied its role in oleic acid (OA)-induced production of reactive oxygen species (ROS), mitochondrial depolarization and injury in cultured renal proximal tubule cells.
  
  
  METHODS
  Renal proximal tubule cells were used and treated with OA: ROS production, mitochondrial depolarization as well as injury were determined. Transcriptional effects of OA on the p66shc gene were determined in a reporter luciferase assay. The role of p66shc in adverse effects of OA was determined using knockdown, p66shc serine36 phosphorylation and cytochrome c binding-deficient cells.
  
  
  RESULTS
  We found that OA increased ROS production via the mitochondria - and to a less extent via the NADPH oxidase - resulting in ROS-dependent mitochondrial depolarization and consequent injury. Interestingly, OA also stimulated the promoter of p66shc. Hence, knockdown of p66shc, impairment its Ser36 phosphorylation (mutation of Ser36 residue to alanine) or cytochrome c binding (W134F mutation) significantly attenuated OA-dependent lipotoxicity.
  
  
  CONCLUSIONS
  These results offer a novel mechanism by which obesity may lead to renal tubular injury and consequently development of CKD. Manipulation of this pathway may offer therapeutic means to ameliorate obesity-dependent renal lipotoxicity.
authors.affiliation: Division of Pediatric Nephrology, Department of Pediatrics, University of Mississippi Medical Center, Jackson, MO 39110, USA. iarany@umc.edu
authors.forename: Istvan
authors.initials: I
authors.lastname: Arany
authors.forename: Jeb S
authors.initials: JS
authors.lastname: Clark
authors.forename: Dustin K
authors.initials: DK
authors.lastname: Reed
authors.forename: Luis A
authors.initials: LA
authors.lastname: Juncos
authors.forename: Mehul
authors.initials: M
authors.lastname: Dixit
mesh_terms: D000818:Animals; D002460:Cell Line; D045304:Cytochromes c / Q000378:metabolism; D004305:Dose-Response Relationship, Drug; D007668:Kidney / Q000187:drug effects* / Q000378:metabolism*; D007684:Kidney Tubules / Q000378:metabolism; D007687:Kidney Tubules, Proximal / Q000187:drug effects / Q000378:metabolism; D051379:Mice; D008928:Mitochondria / Q000378:metabolism; D019255:NADPH Oxidases / Q000378:metabolism; D009765:Obesity / Q000378:metabolism; D019301:Oleic Acid / Q000633:toxicity*; D010766:Phosphorylation; D010957:Plasmids / Q000378:metabolism; D011401:Promoter Regions, Genetic; D017382:Reactive Oxygen Species; D012307:Risk Factors; D012694:Serine / Q000737:chemistry; D055765:Shc Signaling Adaptor Proteins / Q000502:physiology*; D000071425:Src Homology 2 Domain-Containing, Transforming Protein 1
chemical_list: D017382:Reactive Oxygen Species; D055765:Shc Signaling Adaptor Proteins; C528034:Shc1 protein, mouse; D000071425:Src Homology 2 Domain-Containing, Transforming Protein 1; D019301:Oleic Acid; D012694:Serine; D045304:Cytochromes c; D019255:NADPH Oxidases