1. Dietary Selenium Deficiency Partially Rescues Type 2 Diabetes–Like Phenotypes of Glutathione Peroxidase-1 Overexpressing Male Mice Dietary Selenium Deficiency Partially Rescues Type 2 Diabetes–Like Phenotypes of Glutathione Peroxidase-1 Overexpressing Male Mice Xi Yan, Matthew P. Pepper, Marko Z. Vatamaniuk, Carol A. Roneker, Li Li, and Xin Gen Lei Department of Animal Science, Cornell University, Ithaca, NY; and Robert W. Holley Center for Agriculture and Health, Agricultural Research Service, U.S. Department of Agriculture, Ithaca, NY Funding source: NIH DK53018

2. What Is This Study about? 1.To determine if prolonged dietary Se depletion in GPX1 overexpressing (OE) mice rescued their type 2 diabetes–like phenotypes Scopes Metabolic disorders of over-producing a selenoenzyme Se regulation of insulin physiology Novel roles of Se in energy metabolism Objectives 2. To explore if the presumed rescue was mediated by modulating expression and function of key factors related to insulin synthesis, secretion, and function in islets and lipogenesis, glycolysis, and gluconeogenesis in liver and muscle

3. High Se status with adverse blood glucose and lipid profiles High Se on diabetes and insulin resistance in rats and pigs Pro-diabetic Why Is This Study Important? Insulin-mimetic Diabetic association with Se deficiency Anti-diabetic Diabetogenic Dietary Se Mechanism for the multiphased impacts of Se on diabetes?

4. Study 1: Diet restriction (Wang et al., 2008) – Primary phenotype: hyperinsulinemia and elevated insulin secretion Study 2: Diet restriction and Se deficiency (Pepper et al., 2011) – Diet restriction was too drastic to show effect of Se Study 3: Se deficiency on full-fed mice – The present research Proc Natl Acad Sci U S A.Proc Natl Acad Sci U S A. 2004 Jun 15;101(24):8852-7. Epub 2004 Jun 7.

5. Experimental Protocol ♂ Weanling mice (1 month old) 4 groups (n = 5), Se-def. Torula yeast-sucrose basal diet 4 months GroupsWT-WT+OE-OE+ Se, mg/kg (Na 2 SeO 3 ) 00.30 Initial: Body weight ITT, GTT, GSIS Blood analysis Monthly All tests as at initial Final (Month 4): All tests as at initial Tissue collection

6. Laboratory Analysis Biochemical (n=5) Plasma insulin (GSIS) Blood glucose (ITT, GTT) Liver Gpx and lipids Gene regulation (Q-PCR) (n=5) 21 genes in islets 10 genes in liver Controls: β -actin and Gapdh Protein functions (n = 5) Liver/muscle GK & PEPCK Liver p53 protein Data analysis 2 x 2 factorial 6 figures (3 OSM)

7. Dietary Se Deficiency on Phenotype I (Fig. 1) Highlight 1: Se deficiency Liver GPX activity Blood glucose Plasma insulin Genotype differences

8. Dietary Se Deficiency on Phenotype II (Fig. 2) Highlight 2: Se deficiency GTT in OE ITT in OE > WT GSIS in OE Genotype differences

9. Dietary Se Deficiency on Phenotype III (Fig. 3) Highlight 3 Se deficiency Liver TG Liver TC Liver NEFA or removed genotype differences OE > WT

10. WT: Cat, Cfos, Foxo1, Gk1 Hnf4a, Ins1, and p53 OE: Beta2, Foxa2, Cfos, and Pregluc Cat, Hnf1a, Hnf4a, and Kir6.2 Dietary Se Deficiency on Islet Gene Expression (Fig. 4) Overall: Affected 16 genes Removed OE/WT differences in Beta2, Cfos, Foxa2, Ins1, Pregluc, p53, and Sur1

11. WT: Gk1 Cyp7a1, Srebp1a, and Srebp2 OE: Pparγ Acc1 & Gk1 Dietary Se Deficiency on Liver Gene Expression (Fig. 5) OE vs WT: 53-fold Gk1 Higher: Acc1, Cyp7a1, Fasn, Mccc1, and Pparγ Lower: F1,6bp & Hmgcs2

12. WT: Liver p53 Liver GK & PEPCK Genotype differences decreased by Se deficiency OE: Liver GK Muscle PEPCK Dietary Se Deficiency on Tissue Enzymes and p53 (Fig. 6) OE vs WT: 3.5-fold liver GK 7-fold muscle PEPCK Lower liver p53 protein

13. Main Findings and Implications Dietary Se deficiency disallowed the GPX1 overproduction in the full-fed OE mice and partially rescued their type 2 diabetes–like phenotypes The rescue was associated with down-regulation of pro-insulin genes in islets, lipogenesis rate- limiting enzyme genes in liver, and key glycolysis and gluconeogenesis enzymes in liver and/or muscle. We have revealed a strong regulation of hepatic GK mRNA and activity by GPX1 overproduction and dietary Se deficiency, and a novel link of Se/GPX1 to p53 on body energy metabolism.

14. Scheme of Potential Regulatory Pathways

15. Thank you for watching! For additional questions or comments, please contact: Professor X. G. Lei, Ph.D. Cornell University email: xl20@cornell.eduxl20@cornell.edu phone: (607) 254-4703