Human recombinant erythropoietin inhibits interleukin-1beta-stimulated nitric oxide and cyclic guanosine monophosphate production in cultured rat vascular smooth-muscle cells.
BACKGROUND
Recently rat vascular smooth-muscle cells (VSMC) have been shown to possess Epo receptor, and respond to various cytokines for producing nitric oxide (NO). In the present study we examined the effect of pharmacological dose of human recombinant erythropoietin (rHuEpo) on the IL-1beta-induced NO and cGMP production as well as inducible nitric oxide synthase (iNOS) in cultured rat VSMC.


METHODS
Nitrite, a stable metabolite of NO, and intracellular cGMP contents were assayed by Griess method and enzyme immunoassay. iNOS mRNA expression was analysed by Northern blotting.


RESULTS
RHuEpo inhibited IL-1beta-induced nitrite production in a dose- and time-dependent manner with concomitant changes of intracellular cGMP contents. On the other hand, rHuEpo did not inhibit atrial natriuretic peptide- (ANP) or sodium nitroprusside (SNP)-induced nitrite and cGMP production at all. While rHuEpo inhibited IL-1beta-induced iNOS mRNA expression, rHuEpo vehicle did not affect IL-1beta-induced iNOS mRNA expression.


CONCLUSIONS
It is suggested that a pharmacological dose of rHuEpo inhibits IL-1beta-induced NO and cGMP production as well as iNOS mRNA expression, presumably via the Epo receptor.
Kusano
E
E
Department of Nephrology, Jichi Medical School, Tochigi, Japan.
Akimoto
T
T
Inoue
M
M
Masunaga
Y
Y
Umino
T
T
Ono
S
S
Ando
Y
Y
Homma
S
S
Muto
S
S
Komatsu
N
N
Asano
Y
Y
D000818:Animals; D009320:Atrial Natriuretic Factor / Q000097:blood; D002478:Cells, Cultured; D006152:Cyclic GMP / Q000096:biosynthesis*; D004921:Erythropoietin / Q000494:pharmacology*; D006801:Humans; D007375:Interleukin-1 / Q000494:pharmacology*; D008297:Male; D009131:Muscle, Smooth, Vascular / Q000166:cytology / Q000378:metabolism*; D009569:Nitric Oxide / Q000096:biosynthesis*; D019001:Nitric Oxide Synthase / Q000235:genetics; D052247:Nitric Oxide Synthase Type II; D009599:Nitroprusside / Q000494:pharmacology; D012333:RNA, Messenger / Q000032:analysis; D051381:Rats; D017207:Rats, Sprague-Dawley; D017467:Receptors, Erythropoietin / Q000502:physiology; D011994:Recombinant Proteins
D007375:Interleukin-1; D012333:RNA, Messenger; D017467:Receptors, Erythropoietin; D011994:Recombinant Proteins; D004921:Erythropoietin; D009599:Nitroprusside; D009569:Nitric Oxide; D009320:Atrial Natriuretic Factor; C496319:NOS2 protein, human; D019001:Nitric Oxide Synthase; D052247:Nitric Oxide Synthase Type II; C496318:Nos2 protein, rat; D006152:Cyclic GMP