title: Effect of thiol-containing molecule cysteamine on the induction of inducible nitric oxide synthase in hepatocytes.
abstract: BACKGROUND
  Cysteamine, which is a known antioxidant and anti-inflammatory agent, is believed to be a key regulator of essential metabolic pathways in organisms. Cysteamine has beneficial effects in liver damaged by a variety of insults. During liver injury, inducible nitric oxide synthase (iNOS) is induced by lipopolysaccharide or proinflammatory cytokines, leading to excessive nitric oxide (NO) production. Accumulated evidence indicates that NO is an important factor associated with hepatic dysfunction. We examined whether cysteamine influences the induction of iNOS in hepatocytes.
  
  
  METHODS
  Primary cultured rat hepatocytes were treated with interleukin (IL)-1beta in the presence and absence of cysteamine. NO production, iNOS induction, and iNOS signal were analyzed.
  
  
  RESULTS
  IL-1beta stimulated the inhibitory protein kappaB (IkappaB)/nuclear factor kappaB (NFkappaB) pathway, resulting in the activation of NFkappaB (nuclear translocation and DNA binding), which was followed by the induction of iNOS and NO production. The addition of IL-1beta and cysteamine (1-4 mmol/L) markedly inhibited NO production, with a maximal effect at 4 mmol/L (80%-90% inhibition). Cysteamine also decreased the levels of iNOS protein and mRNA. Transfection experiments revealed that cysteamine decreased the transactivation activity of the iNOS promoter. An electrophoretic mobility shift assay demonstrated that cysteamine inhibited the activation of NFkappaB. Furthermore, cysteamine decreased the mRNA levels of the NFkappaB subunit p65 but increased those of the inhibitory protein IkappaB.
  
  
  CONCLUSIONS
  These findings suggest that cysteamine inhibits iNOS induction at the step of NFkappaB activation. Further study is necessary to define the molecular basis of this effect of cysteamine on the regulation of NFkappaB and its pharmacologic implications.
authors: Department of Surgery, Kansai Medical University, Moriguchi, Osaka, Japan.
authors: Takashi
authors: T
authors: Ozaki
authors: Masaki
authors: M
authors: Kaibori
authors: Kosuke
authors: K
authors: Matsui
authors: Katsuji
authors: K
authors: Tokuhara
authors: Hironori
authors: H
authors: Tanaka
authors: Yasuo
authors: Y
authors: Kamiyama
authors: Mikio
authors: M
authors: Nishizawa
authors: Seiji
authors: S
authors: Ito
authors: Tadayoshi
authors: T
authors: Okumura
mesh_terms: D000818:Animals; D002478:Cells, Cultured; D003543:Cysteamine / Q000494:pharmacology*; D004305:Dose-Response Relationship, Drug; D004790:Enzyme Induction / Q000187:drug effects; D022781:Hepatocytes / Q000187:drug effects / Q000201:enzymology* / Q000276:immunology; D006801:Humans; D053583:Interleukin-1beta / Q000494:pharmacology; D008099:Liver / Q000293:injuries; D008297:Male; D016328:NF-kappa B / Q000235:genetics* / Q000378:metabolism*; D009569:Nitric Oxide / Q000096:biosynthesis*; D052247:Nitric Oxide Synthase Type II / Q000037:antagonists & inhibitors* / Q000378:metabolism; D051381:Rats; D017208:Rats, Wistar; D014178:Translocation, Genetic
chemical_list: D053583:Interleukin-1beta; D016328:NF-kappa B; D009569:Nitric Oxide; D003543:Cysteamine; D052247:Nitric Oxide Synthase Type II