Lipopolysaccharide activates nuclear factor kappaB in rat intestine: role of endogenous platelet-activating factor and tumour necrosis factor.
1. We examined the effect of lipopolysaccharide (LPS), a cell wall constituent of Gram negative bacteria, on nuclear factor kappaB (NF-kappaB) activation in the intestine and the roles of endogenous platelet-activating factor (PAF), tumour necrosis factor-alpha (TNF) and neutrophils. We also compared the time course of NF-kappaB activation in response to PAF and LPS. 2. Ileal nuclear extracts from LPS (8 mg kg(-1), IV)-injected rats were assayed for NF-kappaB-DNA-binding activity and identification of the subunits. Some rats were pretreated with WEB2170 (a PAF receptor antagonist), anti-TNF antibody, or anti-neutrophil antiserum. NF-kappaB p65 was localized by immunohistochemistry. An additional group was challenged with PAF (2 microg kg(-1), IV) for comparison. 3. LPS activates intestinal NF-kappaB, both as p50-p50 and p50-p65 dimers within 15 min, and the effect peaks at 2 h. The effect is slower and more sustained than that of PAF, which peaks at 30 min. Activated NF-kappaB was immunolocalized within epithelial and lamina propria cells. LPS effect was reduced by 41, 37 and 44%, respectively, in animals pretreated with WEB2170, anti-TNF antibody, or anti-neutrophil antiserum (P<0.05). 4. LPS activates intestinal NF-kappaB in vivo and neutrophil activation is involved in its action. The LPS effect is mediated by both endogenous PAF and TNF.
De Plaen
I G
IG
Department of Pediatrics (Neonatology), Children's Memorial Hospital, Northwestern University Medical School, Chicago, Illinois, IL 60614, USA.
Tan
X D
XD
Chang
H
H
Wang
L
L
Remick
D G
DG
Hsueh
W
W
D000818:Animals; D019138:Antibodies, Blocking / Q000494:pharmacology; D001381:Azepines / Q000494:pharmacology; D002467:Cell Nucleus / Q000187:drug effects / Q000378:metabolism; D004586:Electrophoresis; D004847:Epithelial Cells / Q000187:drug effects; D007082:Ileum / Q000187:drug effects / Q000378:metabolism; D007150:Immunohistochemistry; D007413:Intestinal Mucosa / Q000378:metabolism*; D007422:Intestines / Q000187:drug effects; D008070:Lipopolysaccharides / Q000494:pharmacology*; D008297:Male; D016328:NF-kappa B / Q000187:drug effects*; D009504:Neutrophils / Q000187:drug effects / Q000378:metabolism; D010972:Platelet Activating Factor / Q000037:antagonists & inhibitors / Q000502:physiology*; D010975:Platelet Aggregation Inhibitors / Q000494:pharmacology; D051381:Rats; D017207:Rats, Sprague-Dawley; D014230:Triazoles / Q000494:pharmacology; D014409:Tumor Necrosis Factor-alpha / Q000037:antagonists & inhibitors / Q000502:physiology*
D019138:Antibodies, Blocking; D001381:Azepines; D008070:Lipopolysaccharides; D016328:NF-kappa B; D010972:Platelet Activating Factor; D010975:Platelet Aggregation Inhibitors; D014230:Triazoles; D014409:Tumor Necrosis Factor-alpha; C063964:bepafant