Serum after partial hepatectomy stimulates iNOS gene transcription via downstream NF-kappa B site.
It has been known that the expression of inducible nitric oxide synthase (iNOS) is up-regulated during hepatic regeneration. The present study characterized the molecular mechanisms involved in the transcriptional activation of iNOS gene by using the serum after partial hepatectomy (post-PH serum) in vitro. The post-PH serum rapidly induced iNOS mRNA expression, which was blocked by anti-tumor necrosis factor-alpha (TNF-alpha) antibody in BNL CL.2 cells, murine embryonic liver cell line. In addition, EMSAs using a NF-kappa B-specific oligomer showed that the up-regulated iNOS mRNA expression in cells treated with post-PH serum correlated with transient activation of NF-kappa B complex (p50/p65 heterodimer). Transient transfection of BNL CL.2 cells with iNOS promoter linked to a CAT reporter gene showed the transcriptional activation of iNOS promoter by post-PH serum. Furthermore, site-directed mutational analysis of the two NF-kappa B sites individually or in combination revealed that iNOS expression by post-PH serum is regulated by the downstream NF-kappa B site, but not by upstream NF-kappa B site. Taken together, these results suggest that the downstream NF-kappa B site acts as an essential component for the iNOS expression by post-PH serum during hepatic regeneration.
Hur
G M
GM
Department of Pharmacology, College of Medicine, Chungnam National University, 6 Munhwa-dong, Jung-gu, Taejon, Korea, 301-131. gmhur@hanbat.chungnam.ac.kr
Ryu
Y S
YS
Hong
J H
JH
Bae
S H
SH
Bae
J Y
JY
Paik
S G
SG
Kim
Y M
YM
Seok
J H
JH
Lee
J H
JH
D000818:Animals; D000906:Antibodies / Q000276:immunology; D001769:Blood; D002460:Cell Line; D003470:Culture Media; D006498:Hepatectomy; D007700:Kinetics; D008115:Liver Regeneration; D051379:Mice; D016328:NF-kappa B / Q000378:metabolism*; D019001:Nitric Oxide Synthase / Q000096:biosynthesis / Q000235:genetics*; D052247:Nitric Oxide Synthase Type II; D011401:Promoter Regions, Genetic; D012333:RNA, Messenger / Q000096:biosynthesis; D051381:Rats; D017207:Rats, Sprague-Dawley; D020218:Response Elements; D015533:Transcriptional Activation; D014409:Tumor Necrosis Factor-alpha / Q000276:immunology
D000906:Antibodies; D003470:Culture Media; D016328:NF-kappa B; D012333:RNA, Messenger; D014409:Tumor Necrosis Factor-alpha; D019001:Nitric Oxide Synthase; D052247:Nitric Oxide Synthase Type II; C496317:Nos2 protein, mouse; C496318:Nos2 protein, rat