Activation of purinergic P2Y2 receptors inhibits inducible NO synthase in cultured rat mesangial cells.
Cytokine-induced nitric oxide (NO) is produced on glomerular inflammation. Glomerular injury and thrombocyte aggregation result in the release of nucleotides, which may regulate induced NO synthesis in cultured rat mesangial cells (MCs). ATP (10(-3) M) inhibited 24-h nitrite production induced by lipopolysaccharide (LPS, 10 microg/ml)/interferon-gamma (IFN-gamma, 100 U/ml) by 48.2 +/- 6. 3%, as well as induction of inducible NOS (iNOS) protein and mRNA. Also, coincubation with either 10(-4) M of UTP, ATP, or ATPgammaS inhibited LPS/IFN-gamma-induced nitrite production by 29.9 +/- 5.8, 36.4 +/- 4.3, and 50.3 +/- 6.5%, respectively, indicating involvement of purinergic P2Y2 receptors. Correspondingly, cultured MCs expressed P2Y2 receptor mRNA. Agonists for other purinergic receptors [alpha,beta-methylene-ATP, 3'-O-(4-benzoyl)-benzoyl-ATP, 2-methylthio-ATP, ADP, UDP, adenosine] were ineffective. Treatment with the protein kinase C (PKC) activator phorbol 12-myristate 13-acetate (PMA, 10(-8) M) reproduced the inhibitory effect of ATP on iNOS protein expression and nitrite inhibition (by 46.6 +/- 10. 4%). The effect of ATP or PMA was reversed by the PKC inhibitors Ro-31-8220 (10(-8) M) and 1-(5-isoquinolinylsulfonyl)-2-methylpiperazine (10(-5) M), indicating that suppression of iNOS is mediated via activation of PKC through stimulated P2Y2 receptors. In conclusion, the release of purine mediators may play a critical role for iNOS expression and synthesis of NO during glomerular inflammatory disorders.
Mohaupt
M G
MG
Nephrologisches Labor, Medizinische Klinik IV, Universität Erlangen-Nürnberg, 91054 Erlangen, Germany.
Fischer
T
T
Schwöbel
J
J
Sterzel
R B
RB
Schulze-Lohoff
E
E
D019307:1-(5-Isoquinolinesulfonyl)-2-Methylpiperazine / Q000494:pharmacology; D000255:Adenosine Triphosphate / Q000031:analogs & derivatives / Q000494:pharmacology*; D000818:Animals; D002478:Cells, Cultured; D004789:Enzyme Activation; D004790:Enzyme Induction / Q000187:drug effects; D004791:Enzyme Inhibitors / Q000494:pharmacology; D005920:Glomerular Mesangium / Q000187:drug effects / Q000201:enzymology / Q000502:physiology*; D007211:Indoles / Q000494:pharmacology; D007371:Interferon-gamma / Q000494:pharmacology*; D008070:Lipopolysaccharides / Q000494:pharmacology; D008297:Male; D019001:Nitric Oxide Synthase / Q000037:antagonists & inhibitors / Q000096:biosynthesis*; D052247:Nitric Oxide Synthase Type II; D014176:Protein Biosynthesis / Q000187:drug effects; D011493:Protein Kinase C / Q000378:metabolism; D012333:RNA, Messenger / Q000096:biosynthesis; D051381:Rats; D017207:Rats, Sprague-Dawley; D018048:Receptors, Purinergic P2 / Q000096:biosynthesis / Q000187:drug effects / Q000502:physiology*; D058473:Receptors, Purinergic P2Y2; D013755:Tetradecanoylphorbol Acetate / Q000494:pharmacology; D014158:Transcription, Genetic / Q000187:drug effects; D019323:omega-N-Methylarginine / Q000494:pharmacology
D004791:Enzyme Inhibitors; D007211:Indoles; D008070:Lipopolysaccharides; C546387:P2ry2 protein, rat; D012333:RNA, Messenger; D018048:Receptors, Purinergic P2; D058473:Receptors, Purinergic P2Y2; D019323:omega-N-Methylarginine; C022571:adenosine 5'-O-(3-thiotriphosphate); D007371:Interferon-gamma; D019307:1-(5-Isoquinolinesulfonyl)-2-Methylpiperazine; D000255:Adenosine Triphosphate; D019001:Nitric Oxide Synthase; D052247:Nitric Oxide Synthase Type II; C496318:Nos2 protein, rat; D011493:Protein Kinase C; D013755:Tetradecanoylphorbol Acetate; C064758:Ro 31-8220