Epidermal growth factor and interleukin-1beta synergistically stimulate the production of nitric oxide in rat intestinal epithelial cells.
Epidermal growth factor (EGF) is one of the trophic factors for intestinal adaptation after small bowel transplantation (SBT). A recent report indicates that nitric oxide (NO) has cytoprotective effects on bacterial translocation (BT) after SBT. We hypothesized that EGF stimulates the expression of the inducible NO synthase (iNOS) gene in the graft after SBT, followed by increased production of NO, resulting in the decrease of BT. Intestinal epithelial cells (IEC)-6 were treated with EGF and/or IL-1beta in the presence and absence of phosphatidylinositol 3-kinase (PI3-kinase) and EGF receptor kinase inhibitors (LY-294002 and tyrphostin A25). The induction of NO production and iNOS and its signal molecules, including the inhibitory protein of NF-kappaB (IkappaB), NF-kappaB, and Akt, were analyzed. IL-1beta stimulated the degradation of IkappaB and the activation of NF-kappaB but had no effect on iNOS induction. EGF, which had no effect on the NF-kappaB activation and iNOS induction, stimulated the upregulation of type 1 IL-1 receptor (IL-1R1) through PI3-kinase/Akt. Simultaneous addition of EGF and IL-1beta stimulated synergistically the induction of iNOS, leading to the increased production of NO. Our results indicate that EGF and IL-1beta stimulate two essential signals for iNOS induction in IEC-6 cells: the upregulation of IL-1R1 through PI3-kinase/Akt and the activation of NF-kappaB through IkappaB kinase, respectively. Simultaneous addition of EGF and IL-1beta can enhance the production of NO, which may contribute to the cytoprotective effect of EGF against intestinal injury.
Second Department of Surgery, Kansai Medical University, 10-15 Fumizonocho, Moriguchi, Osaka 570-8506, Japan.
Katsuhiko
K
Kitagawa
Yoshinori
Y
Hamada
Yasunori
Y
Kato
Koji
K
Nakai
Mikio
M
Nishizawa
Seiji
S
Ito
Tadayoshi
T
Okumura
D000818:Animals; D015152:Blotting, Northern; D015153:Blotting, Western; D002478:Cells, Cultured; D002867:Chromones / Q000494:pharmacology; D004357:Drug Synergism; D004791:Enzyme Inhibitors / Q000494:pharmacology; D004815:Epidermal Growth Factor / Q000494:pharmacology*; D004847:Epithelial Cells / Q000187:drug effects / Q000378:metabolism*; D066246:ErbB Receptors / Q000037:antagonists & inhibitors; D020672:I-kappa B Proteins / Q000378:metabolism; D007375:Interleukin-1 / Q000494:pharmacology*; D007413:Intestinal Mucosa / Q000378:metabolism*; D007422:Intestines / Q000166:cytology / Q000187:drug effects; D009025:Morpholines / Q000494:pharmacology; D016328:NF-kappa B / Q000378:metabolism; D009569:Nitric Oxide / Q000096:biosynthesis*; D019001:Nitric Oxide Synthase / Q000037:antagonists & inhibitors / Q000096:biosynthesis; D052247:Nitric Oxide Synthase Type II; D000081082:Phosphoinositide-3 Kinase Inhibitors; D017346:Protein Serine-Threonine Kinases / Q000096:biosynthesis; D011518:Proto-Oncogene Proteins / Q000096:biosynthesis; D051057:Proto-Oncogene Proteins c-akt; D012333:RNA, Messenger / Q000096:biosynthesis; D051381:Rats; D013205:Staphylococcal Protein A / Q000494:pharmacology
D002867:Chromones; D004791:Enzyme Inhibitors; D020672:I-kappa B Proteins; D007375:Interleukin-1; D009025:Morpholines; D016328:NF-kappa B; D000081082:Phosphoinositide-3 Kinase Inhibitors; D011518:Proto-Oncogene Proteins; D012333:RNA, Messenger; D013205:Staphylococcal Protein A; D009569:Nitric Oxide; C085911:2-(4-morpholinyl)-8-phenyl-4H-1-benzopyran-4-one; D004815:Epidermal Growth Factor; D019001:Nitric Oxide Synthase; D052247:Nitric Oxide Synthase Type II; C496318:Nos2 protein, rat; D066246:ErbB Receptors; C494920:Akt1 protein, rat; D017346:Protein Serine-Threonine Kinases; D051057:Proto-Oncogene Proteins c-akt