title: Knockouts of SOD1 and GPX1 exert different impacts on murine islet function and pancreatic integrity.
abstract: Metabolic subtlety and clinical relevance of different forms of reactive oxygen species in diabetes remain unclear. Using single knockout of Cu,Zn-superoxide dismutase (SOD1(-/-)) or Se-glutathione peroxidase-1 (GPX1(-/-)) and their double-knockout (DKO) mouse models, we determined if elevating endogenously-derived superoxide and hydroperoxide exerted distinct impacts and mechanisms on body glucose homeostasis. Whereas the three knockout groups displayed decreased plasma insulin concentrations and islet β-cells mass, only SOD1(-/-) showed decreased body weight, increased blood glucose, and blocked glucose-stimulated insulin secretion. Null of SOD1 and GPX1 elevated respective islet superoxide and hydroperoxide production, and upregulated p53 phosphorylation. Knockout of SOD1 downregulated the foxhead box A2/pancreatic and duodenal homeobox 1 pathway in a superoxide-dependent fashion at epigenetic, mRNA, and protein levels in islets, but improved insulin signaling in liver and muscle. The SOD1(-/-) mice showed more apparent pancreatitis than the GPX1(-/-) mice that were more susceptible to the cerulein-induced amylase increase. Knockout of SOD1 impaired islet function, pancreas integrity, and body glucose homeostasis more than that of GPX1. Simultaneous ablation of both enzymes did not result in additive or aggravated metabolic outcomes.
authors.affiliation: Department of Animal Science, Cornell University, Ithaca, New York 14853, USA.
authors.forename: Xiaodan
authors.initials: X
authors.lastname: Wang
authors.forename: Marko Z
authors.initials: MZ
authors.lastname: Vatamaniuk
authors.forename: Carol A
authors.initials: CA
authors.lastname: Roneker
authors.forename: Matthew P
authors.initials: MP
authors.lastname: Pepper
authors.forename: Liangbiao G
authors.initials: LG
authors.lastname: Hu
authors.forename: Rebecca A
authors.initials: RA
authors.lastname: Simmons
authors.forename: Xin Gen
authors.initials: XG
authors.lastname: Lei
mesh_terms: D000818:Animals; D001786:Blood Glucose / Q000378:metabolism; D044127:Epigenesis, Genetic; D005786:Gene Expression Regulation; D005979:Glutathione Peroxidase / Q000235:genetics / Q000378:metabolism*; D051542:Hepatocyte Nuclear Factor 3-beta / Q000235:genetics / Q000378:metabolism; D006706:Homeostasis; D006861:Hydrogen Peroxide / Q000378:metabolism; D007328:Insulin / Q000378:metabolism; D007515:Islets of Langerhans / Q000502:physiology*; D051379:Mice; D008810:Mice, Inbred C57BL; D018345:Mice, Knockout; D010179:Pancreas / Q000033:anatomy & histology / Q000502:physiology* / Q000503:physiopathology; D010641:Phenotype; D017382:Reactive Oxygen Species / Q000378:metabolism; D015398:Signal Transduction / Q000502:physiology; D013482:Superoxide Dismutase / Q000235:genetics / Q000378:metabolism*; D013481:Superoxides / Q000378:metabolism; D000094765:Glutathione Peroxidase GPX1
chemical_list: D001786:Blood Glucose; C496503:Foxa2 protein, mouse; D007328:Insulin; D017382:Reactive Oxygen Species; D013481:Superoxides; D051542:Hepatocyte Nuclear Factor 3-beta; D006861:Hydrogen Peroxide; D005979:Glutathione Peroxidase; D013482:Superoxide Dismutase; D000094765:Glutathione Peroxidase GPX1; C000722068:Gpx1 protein, mouse