Intestinal trefoil factor binds to intestinal epithelial cells and induces nitric oxide production: priming and enhancing effects of mucin

Abstract

Intestinal trefoil factor (ITF or TFF3), NO and epitheliumassociated mucin have important roles in sustaining mucosal integrity in the gastrointestinal tract. In the present study we examined ITF-binding molecules on IEC-18 cells (an intestinal epithelial cell line) with the use of flow cytometry and localized these molecules on the cell surface by confocal microscopy. Furthermore, we studied the interaction of mucin and ITF and their co-operative effect on NO production by the epithelium.

Trefoil factors

“…At fi rst glance, TFFs appear to exhibit opposite effects on iNOS-derived NO production. TFF3 stimulates NO production through iNOS in the non-transformed rodent intestinal epithelial cell line, IEC-18 [74]. On the other hand, TFF2 is able to inhibit LPS-induced (but not basal) NO production in a monocyte cell line [75].…”

The trefoil factor family – small peptides with multiple functionalities

“…This suggested that the decreased colonic contents of nitrated protein and the therapeutic effect of TFF2 in the DNBS model were directly related to a TFF2-mediated decrease in expression of iNOS [81,175]. TFF3, on the other hand, has been reported to increase production of NO via increased expression of iNOS, an effect which is enhanced by mucin [199]. Since NO has multiple functions including cytoprotection and anti-inflammatory effects, these in this respect apparently contrasting properties for TFF2 and TFF3 may not be conflicting [200].…”

“…Thus, the combination of TFFs and mucins has been demonstrated to protect cell monolayers against injurious agents, to decrease proton permeation through mucus and to increase mucus viscosity [205 -207]. However, TFF-mucin interactions have also been shown to promote cellular effects like cell migration and NO production [179,199]. Due to variations in their structure, including the shape and numbers of putative mucin binding pockets [37] and free cysteines, it seems likely that each TFF may interact differently with the mucins.…”

“…for tumor spreading [133]. In accord with a role of the TFFs in restitution, the peptides were all found to enhance migration of intestinal epithelial cell lines [45, 162, Anti-apoptosis 1 -3 IEC18, HCT116, AGS, HT-ITF1, IEC6 [46, 145, 182 -184] Scattering/invasion 1 -3 transformed kidney and colonic cells, Rat-2 non transformed fibroblasts [192,195,196] Migration/restitution 1 -3 IEC6, HT29, monocytes, BEAS-2B, corneal epithelium, oral keratinocytes [45,81,151,162,163,169,179,180,193,194] Angiogenesis 1 -3 Chorioallantoic membrane assay, HUVEC on matrigel [197] Immune modulation 2, 3 Monocytes, IEC18, HT29, T84, IEC6 [81,145,148,199,202] Mucin synergies 2, 3 IEC18, IEC6 [179,199,205] Mucin interactions 1 -3 Yeast two-hybrid, rheometry, proton permeation [173,206,207,209] Enhanced transepithelial resistance 3 HT29/B6 [210] Gastric protection and repair 1 -3 Cryoprobe-, indomethacin-, ethanol-, aspirin-or stress-induced ulcers [45, 163 -168] Intestinal protection and repair 1 -3 DSS-, DNBS-, mitomycin C-, acetic acid-, radiation-or chemotherapy-induced colitis. IL-10 -/-mice, necrotizing enterocolitis model [126, 129, 159, 160, 169 -171, 174, 176, 177] 1358 S. Kjellev Biological and functional properties of TFFs 169,179].…”

Trefoil factors

“…Fluorescence-activated cell sorting (FACS) analysis of non-enzymatically detached cells incubated at 4 °C indicated that fl uorescein isothiocyanate (FITC)-or phycoerythin-conjugated mouse anti-biotin antibody bound to the outer surface of these cells in a specifi c manner [19], and that the binding was increased by preincubating in mucin (5 mg/ml for 90 min), a situation that resulted in augmented nitric oxide production upon stimulation with rTFF2 (2.5 µM, 18 h). These data were interpreted as showing that the interaction of rTFF3 with IEC-18 cells was upregulated by mucin.…”