Constitutive expression of IL-18 and IL-18R in differentiated IEC-6 cells: effect of TNF-alpha and IFN-gamma treatment.
The multifunctional cytokine interleukin-18 (IL-18) is an important mediator in intestinal inflammatory processes. The aim of this study was to evaluate the constitutive expression of IL-18 and its receptors (IL-18Ralpha and IL-18Rbeta) in intestinal epithelial cells (IEC) stimulated by tumor necrosis factor-alpha (TNF-alpha) and interferon-gamma (IFN-gamma). In addition, cellular proliferation and evaluation of brush border enzymes as differentiation markers were studied. Nontransformed rat intestinal epithelial IEC-6 cells were grown on an extracellular matrix (ECM) in medium with or without TNF-alpha, IFN-gamma, or a combination of both. Gene expression of IL-18, its receptors and apoptotic markers was evaluated using real-time PCR. Expression of IL-18Ralpha protein was demonstrated by flow cytometry and Western blot. Enzymatic activities of brush border enzymes and caspase-1 were determined. The constitutive expression of IL-18, IL-18Ralpha and IL-18Rbeta mRNAs and proteins were detected in IEC-6 cells. The biologically active form of IL-18 was released in response to TNF-alpha and IFN-gamma treatment. Exogenous IL-18 had no effect on cellular proliferation, brush border enzyme activities, and gene expression of apoptotic markers. However, the addition of IL-18 stimulated production and release of the chemokine IL-8. These data suggest that IEC-6 cells may be not only a source of IL-18 but also a target for its action.
Institute of Physiology of the Academy of Sciences of the Czech Republic, Prague, Czech Republic. kolinska@biomed.cas.cz
Jirina
J
Kolinska
Vera
V
Lisa
Jessica A
JA
Clark
Hana
H
Kozakova
Marie
M
Zakostelecka
Ludmila
L
Khailova
Marek
M
Sinkora
Andrea
A
Kitanovicova
Bohuslav
B
Dvorak
D000818:Animals; D017209:Apoptosis / Q000187:drug effects; D015415:Biomarkers / Q000378:metabolism; D020170:Caspase 1 / Q000378:metabolism; D002452:Cell Count; D002454:Cell Differentiation / Q000187:drug effects*; D002460:Cell Line; D002462:Cell Membrane / Q000187:drug effects / Q000378:metabolism; D018932:Chemokine CCL2 / Q000378:metabolism; D003470:Culture Media; D004847:Epithelial Cells / Q000166:cytology* / Q000187:drug effects / Q000201:enzymology / Q000378:metabolism; D005786:Gene Expression Regulation / Q000187:drug effects; D007371:Interferon-gamma / Q000494:pharmacology*; D020382:Interleukin-18 / Q000235:genetics* / Q000378:metabolism; D053727:Interleukin-18 Receptor alpha Subunit / Q000235:genetics* / Q000378:metabolism; D053728:Interleukin-18 Receptor beta Subunit / Q000235:genetics* / Q000378:metabolism; D007422:Intestines / Q000166:cytology; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D051381:Rats; D020133:Reverse Transcriptase Polymerase Chain Reaction; D014409:Tumor Necrosis Factor-alpha / Q000494:pharmacology*
D015415:Biomarkers; D018932:Chemokine CCL2; D003470:Culture Media; D020382:Interleukin-18; D053727:Interleukin-18 Receptor alpha Subunit; D053728:Interleukin-18 Receptor beta Subunit; D012333:RNA, Messenger; D014409:Tumor Necrosis Factor-alpha; D007371:Interferon-gamma; D020170:Caspase 1