Browsing by Author "Nishiki, Yurika"

Now showing 1 - 2 of 2
  • Thumbnail Image
    Item
    12-Lipoxygenase Promotes Obesity-Induced Oxidative Stress in Pancreatic Islets
    (American Society for Microbiology (ASM), 2014-10) Tersey, Sarah A.; Maier, Bernhard; Nishiki, Yurika; Maganti, Aarthi V.; Nadler, Jerry L.; Mirmira, Raghavendra G.; Department of Pediatrics, IU School of Medicine
    High-fat diets lead to obesity, inflammation, and dysglycemia. 12-Lipoxygenase (12-LO) is activated by high-fat diets and catalyzes the oxygenation of cellular arachidonic acid to form proinflammatory intermediates. We hypothesized that 12-LO in the pancreatic islet is sufficient to cause dysglycemia in the setting of high-fat feeding. To test this, we generated pancreas-specific 12-LO knockout mice and studied their metabolic and molecular adaptations to high-fat diets. Whereas knockout mice and control littermates displayed identical weight gain, body fat distribution, and macrophage infiltration into fat, knockout mice exhibited greater adaptive islet hyperplasia, improved insulin secretion, and complete protection from dysglycemia. At the molecular level, 12-LO deletion resulted in increases in islet antioxidant enzymes Sod1 and Gpx1 in response to high-fat feeding. The absence or inhibition of 12-LO led to increases in nuclear Nrf2, a transcription factor responsible for activation of genes encoding antioxidant enzymes. Our data reveal a novel pathway in which islet 12-LO suppresses antioxidant enzymes and prevents the adaptive islet responses in the setting of high-fat diets.
  • Thumbnail Image
    Item
    Characterization of a novel polyclonal anti-hypusine antibody
    (Springer, 2013-08-29) Nishiki, Yurika; Farb, Thomas B.; Friedrich, Jessica; Bokvist, Krister; Mirmira, Raghavendra G.; Maier, Bernhard; Pediatrics, School of Medicine
    The translation factor eIF5A is the only protein known to contain the amino acid hypusine, which is formed posttranslationally. Hypusinated eIF5A is necessary for cellular proliferation and responses to extracellular stressors, and has been proposed as a target for pharmacologic therapy. Here, we provide the first comprehensive characterization of a novel polyclonal antibody (IU-88) that specifically recognizes the hypusinated eIF5A. IU-88 will be useful for the investigation of eIF5A biology and for the development of assays recognizing hypusinated eIF5A.