Hyperglycemia induces inducible nitric oxide synthase gene expression and consequent nitrosative stress via c-Jun N-terminal kinase activation.
OBJECTIVE
Maternal diabetes has an adverse impact on embryonic development. We tested the hypothesis that hyperglycemia-induced c-Jun N-terminal kinases (JNK) 1/2 activation mediates inducible nitric oxide synthase (iNOS) induction.


METHODS
Levels of iNOS messenger ribonucleic acid (mRNA) and nitrosylated protein were determined in cultured C57BL/6J conceptuses exposed to hyperglycemia (300 mg/dL glucose) and C57BL/6J embryos exposed to streptozotocin-induced diabetes. The iNOS-luciferase activity and endogenous reactive nitrogen species were determined in transfected PYS-2 (mouse teratocarcinoma) cells exposed to hyperglycemia (450 mg/dL glucose).


RESULTS
Hyperglycemia increased iNOS mRNA, and SP600125, a potent JNK1/2 inhibitor, abolished this effect. Hyperglycemia increased iNOS-luciferase activities, and SP600125 blocked this effect. Diabetes increased iNOS mRNA and jnk2 gene deletion abrogated this effect. Correlated with iNOS gene induction, both hyperglycemia in vitro and diabetes in vivo enhanced the production of reactive nitrogen species and increased protein nitrosylation. The jnk2 gene deletion blocked diabetes-induced protein nitrosylation.


CONCLUSIONS
JNK1/2 activation mediates hyperglycemia-induced iNOS gene expression and consequent nitrosative stress in diabetic embryopathy.
Yang
Peixin
P
Department of Obstetrics, Gynecology, and Reproductive Sciences, University of Maryland School of Medicine, Baltimore, MD, USA. tomor2304@yahoo.com
Cao
Yuanning
Y
Li
Hua
H
D000704:Analysis of Variance; D000818:Animals; D015153:Blotting, Western; D003921:Diabetes Mellitus, Experimental / Q000201:enzymology*; D005260:Female; D005786:Gene Expression Regulation; D006943:Hyperglycemia / Q000201:enzymology; D051379:Mice; D008810:Mice, Inbred C57BL; D019950:Mitogen-Activated Protein Kinase 1 / Q000235:genetics* / Q000378:metabolism; D052247:Nitric Oxide Synthase Type II / Q000235:genetics* / Q000378:metabolism; D018384:Oxidative Stress / Q000235:genetics*; D011247:Pregnancy; D011270:Pregnancy, Animal; D011336:Probability; D012333:RNA, Messenger / Q000032:analysis; D020133:Reverse Transcriptase Polymerase Chain Reaction; D015854:Up-Regulation
D012333:RNA, Messenger; D052247:Nitric Oxide Synthase Type II; C535150:MAPK1 protein, human; D019950:Mitogen-Activated Protein Kinase 1