title: Peroxynitrite-induced nitration of cyclooxygenase-2 and inducible nitric oxide synthase promotes their binding in diabetic angiopathy.
abstract: Cyclooxygenase-2 (COX-2) and inducible nitric oxide synthase (iNOS) play crucial roles in diabetic angiopathy. In vivo, however, the following facts remain unknown: whether COX-2 and iNOS bind, how peroxynitrite-induced nitration of COX-2 and iNOS affects their binding if they do bind and what effects of this mechanism contribute to diabetic angiopathy. This study focused on the issues above. Diabetes was induced in Wistar male rats by intraperitoneal injection of streptozotocin. As a specific scavenger of peroxynitrite, urate was used. After 13 wks of diabetes, the morphological and biochemical changes of the rats showed obvious diabetic angiopathy. There exists in vivo colocalization and binding of COX-2 and iNOS in diabetic angiopathy. The nitration level of total and co-immunoprecipitated COX-2 and iNOS increased significantly, and, simultaneously, their binding and activity increased in the diabetes group. In the diabetes + urate group, the nitration level of COX-2 and iNOS decreased and their binding reduced, consistent with their decreased activity and the attenuated pathological changes in the rat aorta and glomerulus. The results provide in vivo evidence that COX-2 and iNOS can bind in diabetic angiopathy and that peroxynitrite-induced nitration of COX-2 and iNOS promotes their binding, contributing to diabetic angiopathy.
authors.affiliation: Department of Molecular Biology, Hebei Key Lab of Laboratory Animal. Hebei Medical University, 361 East Zhongshan Road, Shijiazhuang, PR China.
authors.forename: Yanning
authors.initials: Y
authors.lastname: Li
authors.forename: Jinsheng
authors.initials: J
authors.lastname: Qi
authors.forename: Kun
authors.initials: K
authors.lastname: Liu
authors.forename: Bin
authors.initials: B
authors.lastname: Li
authors.forename: Hui
authors.initials: H
authors.lastname: Wang
authors.forename: Jinhai
authors.initials: J
authors.lastname: Jia
mesh_terms: D000818:Animals; D001011:Aorta / Q000187:drug effects / Q000201:enzymology / Q000473:pathology; D001786:Blood Glucose / Q000378:metabolism; D001835:Body Weight / Q000187:drug effects; D051546:Cyclooxygenase 2 / Q000378:metabolism*; D003925:Diabetic Angiopathies / Q000097:blood / Q000201:enzymology* / Q000473:pathology; D004730:Endothelium, Vascular / Q000187:drug effects / Q000201:enzymology / Q000473:pathology; D047468:Immunoprecipitation; D007672:Kidney Cortex / Q000187:drug effects / Q000201:enzymology / Q000473:pathology / Q000648:ultrastructure; D007678:Kidney Glomerulus / Q000187:drug effects / Q000201:enzymology / Q000473:pathology / Q000648:ultrastructure; D008297:Male; D052247:Nitric Oxide Synthase Type II / Q000378:metabolism*; D015538:Nitrosation / Q000187:drug effects; D030421:Peroxynitrous Acid / Q000494:pharmacology*; D011485:Protein Binding / Q000187:drug effects; D021381:Protein Transport / Q000187:drug effects; D051381:Rats; D017208:Rats, Wistar
chemical_list: D001786:Blood Glucose; D030421:Peroxynitrous Acid; D052247:Nitric Oxide Synthase Type II; C496318:Nos2 protein, rat; D051546:Cyclooxygenase 2; C489691:Ptgs2 protein, rat