Inhibition of protein geranylgeranylation causes a superinduction of nitric-oxide synthase-2 by interleukin-1beta in vascular smooth muscle cells.
Recently, we have designed farnesyltransferase and geranylgeranyltransferase I inhibitors (FTI-277 and GGTI-298) that selectively block protein farnesylation and geranylgeranylation, respectively. In this study, we describe the opposing effects of these inhibitors on interleukin-1beta (IL-1beta)-stimulated induction of nitric-oxide synthase-2 (NOS-2) in rat pulmonary artery smooth muscle cells (RPASMC) and rat hepatocytes. Pretreatment of cells with GGTI-298 caused a superinduction of NOS-2 by IL-1beta. RPASMC treated with GGTI-298 (10 microM) prior to IL-1beta (10 ng/ml) expressed levels of NOS-2 protein five times higher than those exposed to IL-1beta alone. This superinduction of NOS-2 protein by pretreatment with GGTI-298 resulted in nitrite concentrations in the medium that were 5-fold higher at 10 ng/ml IL-1beta and 10-fold higher at 1 ng/ml IL-1beta. Furthermore, NOS-2 mRNA levels in RPASMC were also increased 6- and 14-fold (at 10 and 1 ng/ml IL-1beta, respectively) when the cells were pretreated with GGTI-298. In contrast, treatment of cells with the inhibitor of protein farnesylation, FTI-277 (10 microM), blocked IL-1beta-induced NOS-2 expression at mRNA and protein levels. Pretreatment with lovastatin, an inhibitor of protein prenylation, resulted in superinduction of NOS-2. This superinduction was reversed by geranylgeraniol, but not by farnesol, further confirming that inhibition of geranylgeranylation, not farnesylation, is responsible for enhanced NOS-2 expression. The results demonstrate that a farnesylated protein(s) mediates IL-1beta induction of NOS-2, whereas a geranylgeranylated protein(s) represses this induction.
Finder
J D
JD
Department of Pediatrics, University of Pittsburgh, Pittsburgh, Pennsylvania 15261, USA.
Litz
J L
JL
Blaskovich
M A
MA
McGuire
T F
TF
Qian
Y
Y
Hamilton
A D
AD
Davies
P
P
Sebti
S M
SM
D019883:Alkyl and Aryl Transferases; D000818:Animals; D001549:Benzamides / Q000494:pharmacology; D004790:Enzyme Induction / Q000187:drug effects; D004791:Enzyme Inhibitors / Q000494:pharmacology*; D051231:Farnesyltranstransferase; D019204:GTP-Binding Proteins / Q000378:metabolism; D007375:Interleukin-1 / Q000494:pharmacology*; D008099:Liver / Q000378:metabolism; D008297:Male; D008715:Methionine / Q000031:analogs & derivatives / Q000494:pharmacology; D009131:Muscle, Smooth, Vascular / Q000187:drug effects / Q000201:enzymology*; D019001:Nitric Oxide Synthase / Q000096:biosynthesis*; D009573:Nitrites / Q000378:metabolism; D017368:Protein Prenylation; D011518:Proto-Oncogene Proteins / Q000378:metabolism; D012333:RNA, Messenger / Q000378:metabolism; D051381:Rats; D017207:Rats, Sprague-Dawley; D014157:Transcription Factors / Q000378:metabolism; D014166:Transferases / Q000037:antagonists & inhibitors*; D020668:rap GTP-Binding Proteins; D018631:ras Proteins / Q000378:metabolism
D001549:Benzamides; D004791:Enzyme Inhibitors; C096856:FTI 277; C102521:GGTI 298; D007375:Interleukin-1; D009573:Nitrites; D011518:Proto-Oncogene Proteins; D012333:RNA, Messenger; D014157:Transcription Factors; D008715:Methionine; D019001:Nitric Oxide Synthase; D014166:Transferases; D019883:Alkyl and Aryl Transferases; C083291:geranylgeranyltransferase type-I; D051231:Farnesyltranstransferase; D019204:GTP-Binding Proteins; D020668:rap GTP-Binding Proteins; D018631:ras Proteins