title: Nitric oxide upregulates dimethylarginine dimethylaminohydrolase-2 via cyclic GMP induction in endothelial cells.
abstract: Dimethylarginine dimethylaminohydrolase (DDAH) is an enzyme that metabolizes asymmetrical N(G),N(G)-dimethyl-L-arginine (ADMA) and N(G)-monomethyl-L-arginine (MMA), which are competitive endogenous inhibitors of NO synthase. However, it remains unknown whether NO itself influences DDAH activity and/or ADMA/MMA contents to regulate NO generation via a biofeedback mechanism. The present study was designed to examine the effects of NO on intracellular ADMA and MMA contents and DDAH gene expression levels and enzymatic activities in cultured rat aortic endothelial cells. The NO donors SNAP and NOR3 did not influence DDAH-1 expression but increased DDAH-2 mRNA and protein levels in concentration-dependent manners. SNAP upregulated DDAH enzymatic activity and reduced the MMA and ADMA contents but did not affect the symmetrical N(G),N'(G)-dimethyl-L-arginine and L-arginine levels, thereby negating a mediatory role for system y(+) in ADMA/MMA downregulation. The cGMP agonists 8-bromo-cGMP and C-type natriuretic peptide also stimulated DDAH-2 gene and protein expression levels and DDAH activity and increased the amount of nitrite/nitrate released into the culture supernatants. SNAP-induced DDAH-2 gene expression and DDAH activity were significantly inhibited by a protein kinase G inhibitor, KT5823, and a soluble guanylate cyclase inhibitor, ODQ, suggesting a mediatory role for cGMP in NO-induced DDAH-2 expression. Suppression of DDAH-2 mRNA using small interfering RNA technology abrogated NO-induced DDAH-2 expression. These data demonstrate that NO acts on endothelial cells to induce DDAH-2 expression via a cGMP-mediated process to reduce ADMA/MMA. Thus, the DDAH-2-ADMA/MMA-endothelial NO synthase regulatory pathway and NO-induced cGMP constitute a positive feedback loop that ultimately serves to maintain NO levels in the endothelial environment.
authors.affiliation: Department of Clinical and Molecular Endocrinology, Institute of Biomaterials and Bioengineering, Tokyo Medical and Dental University, Tokyo, Japan.
authors.forename: Maya
authors.initials: M
authors.lastname: Sakurada
authors.forename: Masayoshi
authors.initials: M
authors.lastname: Shichiri
authors.forename: Masatoshi
authors.initials: M
authors.lastname: Imamura
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Azuma
authors.forename: Yukio
authors.initials: Y
authors.lastname: Hirata
mesh_terms: D000581:Amidohydrolases / Q000235:genetics / Q000378:metabolism*; D000818:Animals; D001120:Arginine / Q000031:analogs & derivatives / Q000378:metabolism; D002227:Carbazoles / Q000494:pharmacology; D002478:Cells, Cultured; D006152:Cyclic GMP / Q000819:agonists / Q000031:analogs & derivatives / Q000378:metabolism* / Q000494:pharmacology; D004730:Endothelium, Vascular / Q000166:cytology / Q000187:drug effects / Q000378:metabolism*; D008297:Male; D020098:Natriuretic Peptide, C-Type / Q000494:pharmacology; D009569:Nitric Oxide / Q000502:physiology*; D020030:Nitric Oxide Donors / Q000494:pharmacology; D052247:Nitric Oxide Synthase Type II / Q000378:metabolism; D052250:Nitric Oxide Synthase Type III; D009574:Nitro Compounds / Q000494:pharmacology; D047428:Protein Kinase Inhibitors / Q000494:pharmacology; D012333:RNA, Messenger / Q000378:metabolism; D051381:Rats; D017207:Rats, Sprague-Dawley; D026423:S-Nitroso-N-Acetylpenicillamine / Q000494:pharmacology; D015854:Up-Regulation / Q000187:drug effects*; D019323:omega-N-Methylarginine / Q000378:metabolism
chemical_list: D002227:Carbazoles; D020030:Nitric Oxide Donors; D009574:Nitro Compounds; D047428:Protein Kinase Inhibitors; D012333:RNA, Messenger; C073601:KT 5823; D020098:Natriuretic Peptide, C-Type; D019323:omega-N-Methylarginine; C016276:8-bromocyclic GMP; D009569:Nitric Oxide; C018524:N,N-dimethylarginine; D026423:S-Nitroso-N-Acetylpenicillamine; C061872:FK 409; D001120:Arginine; D052247:Nitric Oxide Synthase Type II; D052250:Nitric Oxide Synthase Type III; C496316:Nos3 protein, rat; D000581:Amidohydrolases; C059999:dimethylargininase; D006152:Cyclic GMP