Modulation of cGMP by human HO-1 retrovirus gene transfer in pulmonary microvessel endothelial cells.
Carbon monoxide (CO) stimulates guanylate cyclase (GC) and increases guanosine 3',5'-cyclic monophosphate (cGMP) levels. We transfected rat-lung pulmonary endothelial cells with a retrovirus-mediated human heme oxygenase (hHO)-1 gene. Pulmonary cells that expressed hHO-1 exhibited a fourfold increase in HO activity associated with decreases in the steady-state levels of heme and cGMP without changes in soluble GC (sGC) and endothelial nitric oxide synthase (NOS) proteins or basal nitrite production. Heme elicited significant increases in CO production and intracellular cGMP levels in both pulmonary endothelial and pulmonary hHO-1-expressing cells. N(omega)-nitro-L-arginine methyl ester (L-NAME), an inhibitor of NOS, significantly decreased cGMP levels in heme-treated pulmonary endothelial cells but not heme-treated hHO-1-expressing cells. In the presence of exogenous heme, CO and cGMP levels in hHO-1-expressing cells exceeded the corresponding levels in pulmonary endothelial cells. Acute exposure of endothelial cells to SnCl2, which is an inducer of HO-1, increased cGMP levels, whereas chronic exposure decreased heme and cGMP levels. These results indicate that prolonged overexpression of HO-1 ultimately decreases sGC activity by limiting the availability of cellular heme. Heme activates sGC and enhances cGMP levels via a mechanism that is largely insensitive to NOS inhibition.
Abraham
Nader G
NG
Department of Pharmacology, New York Medical College, Valhalla, New York 10595, USA. nader_abraham@nymc.edu
Quan
Shuo
S
Mieyal
Paul A
PA
Yang
Liming
L
Burke-Wolin
Theresa
T
Mingone
Christopher J
CJ
Goodman
Alvin I
AI
Nasjletti
Alberto
A
Wolin
Michael S
MS
D000818:Animals; D006152:Cyclic GMP / Q000502:physiology*; D004730:Endothelium, Vascular / Q000201:enzymology*; D006418:Heme / Q000502:physiology; D006419:Heme Oxygenase (Decyclizing) / Q000235:genetics / Q000378:metabolism*; D051547:Heme Oxygenase-1; D006801:Humans; D008565:Membrane Proteins; D008833:Microcirculation / Q000187:drug effects / Q000502:physiology*; D019331:NG-Nitroarginine Methyl Ester / Q000494:pharmacology; D019001:Nitric Oxide Synthase / Q000378:metabolism; D052250:Nitric Oxide Synthase Type III; D009573:Nitrites / Q000378:metabolism; D011652:Pulmonary Circulation / Q000187:drug effects / Q000502:physiology*; D051381:Rats; D011994:Recombinant Proteins / Q000378:metabolism; D012190:Retroviridae; D020133:Reverse Transcriptase Polymerase Chain Reaction; D014162:Transfection
D008565:Membrane Proteins; D009573:Nitrites; D011994:Recombinant Proteins; D006418:Heme; C496314:NOS3 protein, human; D019001:Nitric Oxide Synthase; D052250:Nitric Oxide Synthase Type III; C496316:Nos3 protein, rat; C496541:HMOX1 protein, human; D006419:Heme Oxygenase (Decyclizing); D051547:Heme Oxygenase-1; D006152:Cyclic GMP; D019331:NG-Nitroarginine Methyl Ester