title: The p66(Shc) redox adaptor protein is induced by saturated fatty acids and mediates lipotoxicity-induced apoptosis in pancreatic beta cells.
abstract: OBJECTIVE
  The role of the redox adaptor protein p66(Shc) as a potential mediator of saturated fatty acid (FA)-induced beta cell death was investigated.
  
  
  METHODS
  The effects of the FA palmitate on p66(Shc) expression were evaluated in human and murine islets and in rat insulin-secreting INS-1E cells. p66(Shc) expression was also measured in islets from mice fed a high-fat diet (HFD) and from human donors with different BMIs. Cell apoptosis was quantified by two independent assays. The role of p66(Shc) was investigated using pancreatic islets from p66 (Shc-/-) mice and in INS-1E cells with knockdown of p66(Shc) or overexpression of wild-type and phosphorylation-defective p66(Shc). Production of reactive oxygen species (ROS) was evaluated by the dihydroethidium oxidation method.
  
  
  RESULTS
  Palmitate induced a selective increase in p66(Shc) protein expression and phosphorylation on Ser(36) and augmented apoptosis in human and mouse islets and in INS-1E cells. Inhibiting the tumour suppressor protein p53 prevented both the palmitate-induced increase in p66(Shc) expression and beta cell apoptosis. Palmitate-induced apoptosis was abrogated in islets from p66 (Shc-/-) mice and following p66 (Shc) knockdown in INS-1E cells; by contrast, overexpression of p66(Shc), but not that of the phosphorylation-defective p66(Shc) mutant, enhanced palmitate-induced apoptosis. The pro-apoptotic effects of p66(Shc) were dependent upon its c-Jun N-terminal kinase-mediated phosphorylation on Ser(36) and associated with generation of ROS. p66(Shc) protein expression and function were also elevated in islets from HFD-fed mice and from obese/overweight cadaveric human donors.
  
  
  CONCLUSIONS
  p53-dependent augmentation of p66(Shc) expression and function represents a key signalling response contributing to beta cell apoptosis under conditions of lipotoxicity.
authors: Department of Emergency and Organ Transplantation, Section of Internal Medicine, Endocrinology, Andrology and Metabolic Diseases, University of Bari Aldo Moro, Piazza Giulio Cesare, 11, 70124, Bari, Italy.
authors: Annalisa
authors: A
authors: Natalicchio
authors: Federica
authors: F
authors: Tortosa
authors: Rossella
authors: R
authors: Labarbuta
authors: Giuseppina
authors: G
authors: Biondi
authors: Nicola
authors: N
authors: Marrano
authors: Emanuele
authors: E
authors: Carchia
authors: Anna
authors: A
authors: Leonardini
authors: Angelo
authors: A
authors: Cignarelli
authors: Marco
authors: M
authors: Bugliani
authors: Piero
authors: P
authors: Marchetti
authors: Gian Paolo
authors: GP
authors: Fadini
authors: Marco
authors: M
authors: Giorgio
authors: Angelo
authors: A
authors: Avogaro
authors: Sebastio
authors: S
authors: Perrini
authors: Luigi
authors: L
authors: Laviola
authors: Francesco
authors: F
authors: Giorgino
mesh_terms: D000256:Adenoviridae / Q000235:genetics; D000368:Aged; D000818:Animals; D017209:Apoptosis; D015992:Body Mass Index; D059305:Diet, High-Fat; D005227:Fatty Acids / Q000378:metabolism*; D005260:Female; D020869:Gene Expression Profiling; D006801:Humans; D050417:Insulin-Secreting Cells / Q000166:cytology*; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL; D008822:Mice, Transgenic; D008875:Middle Aged; D010084:Oxidation-Reduction; D010766:Phosphorylation; D034741:RNA, Small Interfering / Q000378:metabolism; D051381:Rats; D017382:Reactive Oxygen Species / Q000378:metabolism; D055765:Shc Signaling Adaptor Proteins / Q000378:metabolism*; D015398:Signal Transduction; D000071425:Src Homology 2 Domain-Containing, Transforming Protein 1; D016159:Tumor Suppressor Protein p53 / Q000378:metabolism
chemical_list: D005227:Fatty Acids; D034741:RNA, Small Interfering; D017382:Reactive Oxygen Species; C528024:SHC1 protein, human; D055765:Shc Signaling Adaptor Proteins; C528034:Shc1 protein, mouse; C528035:Shc1 protein, rat; D000071425:Src Homology 2 Domain-Containing, Transforming Protein 1; C495901:TP53 protein, human; D016159:Tumor Suppressor Protein p53