Oxidative Stress Induces Nucleo-Cytoplasmic Translocation of Pancreatic Transcription Factor PDX-1 Through Activation of c-Jun NH2-terminal Kinase

• Published in: Diabetes (New York, N.Y.) Vol. 52; no. 12; pp. 2896 - 2904
• Main Authors: KAWAMORI, Dan, KAJIMOTO, Yoshitaka, KANETO, Hideaki, UMAYAHARA, Yutaka, FUJITANI, Yoshio, MIYATSUKA, Takeshi, WATADA, Hirotaka, LEIBIGER, Ingo B, YAMASAKI, Yoshimitsu, HORI, Masatsugu
• Format: Journal Article
• Language: English
• Published: Alexandria, VA American Diabetes Association 01.12.2003
• Subjects: Biological and medical sciences; Diabetes. Impaired glucose tolerance; Endocrine pancreas; Endocrine pancreas. Apud cells (diseases); Endocrinopathies; Fundamental and applied biological sciences. Psychology; Medical sciences; Morphology. Functional localizations; Vertebrates: endocrinology; Endocrinopathy; Translocation; Oxidative stress; Enzyme; Kinase; Transferases; Diabetes mellitus; Transcription factor; Pancreas; Protooncogene; Immediate early gene
• ISSN: 0012-1797; 1939-327X
• DOI: 10.2337/diabetes.52.12.2896

Oxidative Stress Induces Nucleo-Cytoplasmic Translocation of Pancreatic Transcription Factor PDX-1 Through Activation of c-Jun NH 2 -terminal Kinase Dan Kawamori 1 , Yoshitaka Kajimoto 1 , Hideaki Kaneto 1 , Yutaka Umayahara 1 , Yoshio Fujitani 1 , Takeshi Miyatsuka 1 , Hirotaka Watada 1 , Ingo B. Leibiger 2 , Yoshimitsu Yamasaki 1 and Masatsugu Hori 1 1 Department of Internal Medicine and Therapeutics, Osaka University Graduate School of Medicine, Suita City, Osaka, Japan 2 The Rolf Luft Center for Diabetes Research, Department of Molecular Medicine, Karolinska Institutet, Stockholm, Sweden Address correspondence and reprint requests to Dr. H. Kaneto, Department of Internal Medicine and Therapeutics (A8), Osaka University Graduate School of Medicine, 2-2 Yamadaoka, Suita City, Osaka Pref. 565-0871, Japan. E-mail: kaneto{at}medone.med.osaka-u.ac.jp Abstract Oxidative stress is induced in pancreatic β-cells under diabetic conditions and causes β-cell dysfunction. Antioxidant treatment of diabetic animals leads to recovery of insulin biosynthesis and increases the expression of its controlling transcription factor, pancreatic duodenal homeobox-1 (PDX-1), in pancreatic β-cells. Here, we show that PDX-1 is translocated from the nuclei to the cytoplasm of pancreatic β-cells in response to oxidative stress. When oxidative stress was charged upon β-cell-derived HIT-T15 cells, both endogenous PDX-1 and exogenously introduced green fluorescent protein-tagged PDX-1 moved from the nuclei to the cytoplasm. The addition of a dominant negative form of c-Jun NH 2 -terminal kinase (JNK) inhibited oxidative stress-induced PDX-1 translocation, suggesting an essential role of JNK in mediating this phenomenon. Whereas the nuclear localization signal (NLS) in PDX-1 was not affected by oxidative stress, leptomycin B, a specific inhibitor of the classical leucine-rich nuclear export signal (NES), inhibited nucleo-cytoplasmic translocation of PDX-1 induced by oxidative stress. Moreover, we identified an NES at position 82-94 of the mouse PDX-1 protein. Thus, our present results revealed a novel mechanism that negatively regulates PDX-1 function. The identification of the NES, which overrides the function of the NLS in an oxidative stress-responsive, JNK-dependent manner, supports the complicated regulation of PDX-1 function in vivo and may further the understanding of β-cell pathophysiology in diabetes. ABC, avidin-biotin complex DAPI, 4′, 6-diamidino-2-phenylindole DTT, dithiothreitol GFP, green fluorescent protein IB1, islet-brain-1 JNK, c-Jun NH2-terminal kinase MAPK, mitogen-activated protein kinase NAC, N-acetyl l-cysteine NES, nuclear export signal NLS, nuclear localization signal PDX-1, pancreatic duodenal homeobox-1 ROS, reactive oxygen species USF-1, upstream stimulating factor-1 Footnotes H.W. is currently located at the Department of Medicine, Metabolism and Endocrinology, Juntendo University School of Medicine, Tokyo 113-8421, Japan. Accepted September 18, 2003. Received July 8, 2003. DIABETES