cAMP enhances inducible nitric oxide synthase mRNA stability in cardiac myocytes.
The effects of adenosine 3',5'-cyclic monophosphate (cAMP) on cardiac myocyte nitric oxide (NO) production were studied. Maximal nitrite (NO2(-)) production by cultured neonatal rat cardiac myocytes was achieved with 500 U/ml interleukin-1 beta (IL-1 beta) for 48 h (4.6 +/- 0.3 nmol/1.25 x 10(5) cells; n = 12). Cardiac myocytes exposed to 500 U/ml IL-1 beta for 48 h stained positively for inducible nitric oxide synthase (iNOS) by immunohistochemistry. Forskolin (FSK; adenylate cyclase stimulator) or dibutyryl cAMP (DBcAMP; membrane-permeable cAMP analogue) administration alone had no effect on NO2(-) production. The addition of FSK or DBcAMP to IL-1 beta significantly increased NO2-) levels vs. IL-1 beta alone (9.7 +/- 0.6 and 10.9 +/- 0.8 vs. 4.6 +/- 0.3 nmol/1.25 x 10(5) cells per 48 h, respectively; P < 0.01; n = 12). Semiquantitative reverse transcriptase-polymerase chain reaction revealed increased iNOS mRNA in myocytes treated with FSK+IL-1 beta or DBcAMP+IL-1 beta vs. those treated with IL-1 beta alone. The addition of FSK or DBcAMP to IL-1 beta increased iNOS mRNA half-life over IL-1 beta treatment alone (10.6, 11.7 vs. 2.4 h, respectively). Cardiac myocytes do not express iNOS in response to cAMP alone. Rather, cAMP enhances iNOS mRNA stability following cytokine exposure.
Oddis
C V
CV
Department of Pathology, University of Pittsburgh School of Medicine, Pennsylvania 15213, USA.
Simmons
R L
RL
Hattler
B G
BG
Finkel
M S
MS
D000818:Animals; D001483:Base Sequence; D003994:Bucladesine / Q000494:pharmacology; D002478:Cells, Cultured; D005576:Colforsin / Q000494:pharmacology; D000242:Cyclic AMP / Q000494:pharmacology*; D004355:Drug Stability; D004790:Enzyme Induction; D007375:Interleukin-1 / Q000494:pharmacology; D015335:Molecular Probes / Q000235:genetics; D008969:Molecular Sequence Data; D009206:Myocardium / Q000166:cytology / Q000378:metabolism*; D019001:Nitric Oxide Synthase / Q000235:genetics*; D016133:Polymerase Chain Reaction; D012333:RNA, Messenger / Q000378:metabolism*; D051381:Rats; D014158:Transcription, Genetic
D007375:Interleukin-1; D015335:Molecular Probes; D012333:RNA, Messenger; D005576:Colforsin; D003994:Bucladesine; D000242:Cyclic AMP; D019001:Nitric Oxide Synthase