An anti-ulcer drug, geranylgeranylacetone, suppresses inducible nitric oxide synthase in cultured vascular smooth muscle cells.
OBJECTIVE
Geranylgeranylacetone (GGA) is commonly used as an anti-ulcer drug. If GGA affects inducible nitric oxide synthase (iNOS) in the vascular tissue, it could influence disease progression in coronary arteries. We investigated the effects of the anti-ulcer drug GGA on iNOS activity in vascular smooth muscle cells.


METHODS
We measured the production of nitrite, a stable metabolite of nitric oxide, in cultured rat vascular smooth muscle cells with the Griess reagent. iNOS protein and mRNA expressions were assayed by western blotting and northern blotting, respectively. The levels of nuclear factor (NF)-kappaB proteins in nuclear extracts were analyzed by gel retardation assay. Heat shock protein 70, a cytoprotective molecule, was evaluated by western blotting.


RESULTS
Incubation of cultures with interleukin-1beta for 24 h caused a significant increase in nitrite generation. Interleukin-1beta-induced nitrite production by vascular smooth muscle cells was significantly suppressed by GGA in a dose-dependent manner. GGA-suppressed nitrite production was accompanied by decreased iNOS mRNA and protein accumulations. GGA by itself did not modulate the basal level of nitrite production. Interleukin-1beta induced NF-kappaB activation in vascular smooth muscle cells, and the addition of GGA further inhibited this NF-kappaB activation. GGA itself induced heat shock protein 70 expression in a dose-dependent manner.


CONCLUSIONS
These findings demonstrated that GGA suppresses iNOS expression in cytokine-stimulated cultured vascular smooth muscle cells partially through the suppression of NF-kappaB activation, suggesting that GGA may modulate the pathophysiology of cardiovascular diseases including atherosclerosis. In addition, this effect may be associated with heat shock protein 70 production by GGA.
Yamamoto
Keiji
K
Division of Cardiovascular Medicine, Jichi Medical School, Tochigi, Japan. kyamamoto@jichi.ac.jp
Sarukawa
Mutsuko
M
Ito
Takayuki
T
Aoki
Hirotaka
H
Ichida
Masaru
M
Shimada
Kazuyuki
K
D000818:Animals; D000897:Anti-Ulcer Agents / Q000494:pharmacology; D015152:Blotting, Northern; D015153:Blotting, Western; D002478:Cells, Cultured; D004224:Diterpenes / Q000494:pharmacology*; D004305:Dose-Response Relationship, Drug; D015971:Gene Expression Regulation, Enzymologic / Q000187:drug effects; D018840:HSP70 Heat-Shock Proteins / Q000378:metabolism; D006358:Hot Temperature; D007375:Interleukin-1 / Q000494:pharmacology; D009131:Muscle, Smooth, Vascular / Q000166:cytology / Q000187:drug effects* / Q000378:metabolism; D016328:NF-kappa B / Q000378:metabolism; D052247:Nitric Oxide Synthase Type II / Q000235:genetics* / Q000378:metabolism; D009573:Nitrites / Q000378:metabolism; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D051381:Rats; D017207:Rats, Sprague-Dawley; D013997:Time Factors
D000897:Anti-Ulcer Agents; D004224:Diterpenes; D018840:HSP70 Heat-Shock Proteins; D007375:Interleukin-1; D016328:NF-kappa B; D009573:Nitrites; D012333:RNA, Messenger; D052247:Nitric Oxide Synthase Type II; C031049:geranylgeranylacetone