Differential pattern of inflammatory molecule regulation in intestinal epithelial cells stimulated with IL-1.
To better predict the consequences of blocking signal transduction pathways as a means of controlling intestinal inflammation, we are characterizing the pathways up-regulated by IL-1 in intestinal epithelial cells (IEC). IL-1beta induced increased mRNA levels of MIP-2, MCP-1, RANTES, inducible NO synthase (iNOS), and cyclooxygenase-2 (COX-2) in the IEC-18 cell line. IL-1beta activated NF-kappaB but not ERK or p38. Infecting cells with adenovirus expressing a mutated gene for IkappaBalpha (IkappaBAA) blocked IL-1-induced mRNA increases in MIP-2, MCP-1, and iNOS but not COX-2 or RANTES. Expression of IkappaBAA attenuated the IL-1-induced increase in COX-2 protein. Unexpectedly, RANTES mRNA increased, and protein was secreted by cells expressing IkappaBAA in the absence of IL-1. Adenovirus-expressing IkappaBAA, blocking protein synthesis, and IL-1beta all resulted in activation of JNK. The JNK inhibitor SP600125 prevented the RANTES increases by all three stimuli. A human enterocyte line was similarly examined, and both NF-kappaB and JNK regulate IL-1-induced RANTES secretion. We conclude that in IEC-18, IL-1beta-induced increases in mRNA for MIP-2, MCP-1, and iNOS are NF-kappaB-dependent, whereas regulation of RANTES mRNA is independent of NF-kappaB but is positively regulated by JNK. IL-1beta-induced mRNA increases in COX-2 mRNA are both NF-kappaB- and MAPK-independent but the translation of COX-2 protein is NF-kappaB-dependent. This pattern of signaling due to a single stimulus exposed the complexities of regulating inflammatory genes in IEC.
Yan
Sen Rong
SR
Department of Pediatrics, Dalhousie Universiy, Halifax, Nova Scotia, Canada.
Joseph
Robbie R
RR
Wang
Jun
J
Stadnyk
Andrew W
AW
D002460:Cell Line; D051546:Cyclooxygenase 2 / Q000235:genetics; D004847:Epithelial Cells / Q000187:drug effects / Q000378:metabolism / Q000473:pathology; D004912:Erythrocytes / Q000378:metabolism; D005786:Gene Expression Regulation / Q000187:drug effects*; D006801:Humans; D007249:Inflammation / Q000378:metabolism*; D007375:Interleukin-1 / Q000494:pharmacology*; D007413:Intestinal Mucosa / Q000187:drug effects / Q000378:metabolism* / Q000473:pathology; D048031:JNK Mitogen-Activated Protein Kinases / Q000378:metabolism; D008565:Membrane Proteins / Q000235:genetics; D016328:NF-kappa B / Q000378:metabolism; D012333:RNA, Messenger / Q000032:analysis / Q000187:drug effects; D015398:Signal Transduction; D015854:Up-Regulation / Q000187:drug effects
D007375:Interleukin-1; D008565:Membrane Proteins; D016328:NF-kappa B; D012333:RNA, Messenger; D051546:Cyclooxygenase 2; C496540:PTGS2 protein, human; D048031:JNK Mitogen-Activated Protein Kinases