title: Protective effects of polyamine depletion in mouse models of type 1 diabetes: implications for therapy.
abstract: The underlying pathophysiology of type 1 diabetes involves autoimmune-mediated islet inflammation, leading to dysfunction and death of insulin-secreting islet β cells. Recent studies have shown that polyamines, which are essential for mRNA translation, cellular replication, and the formation of the hypusine modification of eIF5A may play an important role in the progression of cellular inflammation. To test a role for polyamines in type 1 diabetes pathogenesis, we administered the ornithine decarboxylase inhibitor difluoromethylornithine to two mouse models--the low-dose streptozotocin model and the NOD model--to deplete intracellular polyamines, and administered streptozotocin to a third model, which was haploinsufficient for the gene encoding the hypusination enzyme deoxyhypusine synthase. Subsequent development of diabetes and/or glucose intolerance was monitored. In the low-dose streptozotocin mouse model, continuous difluoromethylornithine administration dose-dependently reduced the incidence of hyperglycemia and led to the preservation of β cell area, whereas in the NOD mouse model of autoimmune diabetes difluoromethylornithine reduced diabetes incidence by 50%, preserved β cell area and insulin secretion, led to reductions in both islet inflammation and potentially diabetogenic Th17 cells in pancreatic lymph nodes. Difluoromethylornithine treatment reduced hypusinated eIF5A levels in both immune cells and islets. Animals haploinsufficient for the gene encoding deoxyhypusine synthase were partially protected from hyperglycemia induced by streptozotocin. Collectively, these studies suggest that interventions that interfere with polyamine biosynthesis and/or eIF5A hypusination may represent viable approaches in the treatment of diabetes.
authors.affiliation: Department of Pediatrics and the Herman B Wells Center for Pediatric Research, Indiana University School of Medicine, 635 Barnhill Drive, MS2031B, Indianapolis, IN, 46202, USA.
authors.forename: Sarah A
authors.initials: SA
authors.lastname: Tersey
authors.forename: Stephanie C
authors.initials: SC
authors.lastname: Colvin
authors.forename: Bernhard
authors.initials: B
authors.lastname: Maier
authors.forename: Raghavendra G
authors.initials: RG
authors.lastname: Mirmira
mesh_terms: D000818:Animals; D003921:Diabetes Mellitus, Experimental / Q000139:chemically induced / Q000188:drug therapy* / Q000378:metabolism; D003922:Diabetes Mellitus, Type 1 / Q000139:chemically induced / Q000188:drug therapy* / Q000378:metabolism; D004195:Disease Models, Animal; D004305:Dose-Response Relationship, Drug; D000518:Eflornithine / Q000008:administration & dosage; D005260:Female; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL; D016688:Mice, Inbred NOD; D018345:Mice, Knockout; D000587:Oxidoreductases Acting on CH-NH Group Donors / Q000172:deficiency / Q000378:metabolism; D010448:Peptide Initiation Factors / Q000378:metabolism; D011073:Polyamines / Q000378:metabolism*; D016601:RNA-Binding Proteins / Q000378:metabolism; D013311:Streptozocin / Q000008:administration & dosage; D000097574:Eukaryotic Translation Initiation Factor 5A
chemical_list: D000518:Eflornithine; D000587:Oxidoreductases Acting on CH-NH Group Donors; D010448:Peptide Initiation Factors; D011073:Polyamines; D016601:RNA-Binding Proteins; D013311:Streptozocin; D000097574:Eukaryotic Translation Initiation Factor 5A; C063507:deoxyhypusine synthase