PMC:2800179 JSONTXT 21 Projects

Annnotations TAB TSV DIC JSON TextAE

Id Subject Object Predicate Lexical cue Negation Speculation
T53 45-52 Positive_regulation denotes Induces
T54 45-52 Positive_regulation denotes Induces
T55 53-56 Protein denotes TNF
T56 57-66 Localization denotes Secretion
T57 71-77 Protein denotes ICAM-1
T58 78-90 Positive_regulation denotes Upregulation
T60 104-111 Positive_regulation denotes through
T59 104-111 Positive_regulation denotes through
T61 655-661 Protein denotes ICAM-1
T62 662-679 Protein denotes adhesion molecule
T7226 878-17731 Positive_regulation denotes inhibited THP-1 cell proliferation in vitro, arresting the cells in G1 phase. In addition, dCGN increased ICAM-1 expression in both PBM and THP-1 cells with a major effect seen after 40 kDa dCGN exposure. Also, dCGN stimulated monocyte aggregation in vitro that was prevented by incubation with anti-ICAM-1 antibody. Finally, dCGN stimulated TNF-α expression and secretion by both PBM and THP-1 cells. All these effects were linked to NF-κB activation. These data strongly suggest that the degraded forms of CGN have a pronounced effect on monocytes, characteristic of an inflammatory phenotype. Introduction Carrageenan (CGN) is a high molecular weight sulphated polysaccharide (>200 kDa) derived from red algae (Rhodophyceae). Three main forms of CGN have been identified: kappa, iota, and lambda. They differ from each other in sulphation degree and solubility [1], [2]. Native CGN is thought to be harmless and is widely used as a food additive to improve texture. It is also used in cosmetics and pharmaceuticals. However, acid treatment at high temperature (80°C) triggers CGN hydrolysis to lower molecular weight (<50 kDa) compounds known as poligeenan or degraded CGN (dCGN). These dCGNs induce inflammation and have been widely used as models of colitis in several species, including rats [3], rabbits [4] and guinea pigs [5]. The role of dCGN as a tumor-promoting factor remains controversial [4], [6]–[8]. Although the native form is thought to be harmless for human consumption, small amounts of dCGN are probably produced by acid hydrolysis during gastric digestion [9], [10] or interaction with intestinal bacteria [11], [12]. Whereas the effects of native and dCGN on intestinal inflammation have been extensively analyzed in animal models, only few studies have been conducted using human cell lines. Recent studies have shown a link between exposure to native form CGN and IL-8 production by the human intestinal epithelial cell line, NCM460, via Nuclear Factor-κB (NF-κB) activation [13], [14]. NF-κB is a transcription factor that regulates the expression of genes associated with inflammation [15], [16]. Macrophage infiltration and accumulation is a common characteristic of intestinal diseases [17]. Macrophages represent 10% of total lamina propria cells, secrete a wide range of biologically active compounds and express cell-adhesion molecules. The immune cell response to an inflammatory stimulus seems to be amplified or directly generated by cells exposed to sulphated polysaccharides such as carrageenans. Indeed, inflammation induced by dCGN was associated with recruitment of macrophages to inflammation sites [18], [19]. Also, inflammation induced by Dextran Sulphate Sodium (DSS), another sulphated compound, was directly associated with macrophages recruitment [20], since DSS still provoked inflammation after T-lymphocyte and NK cell depletion [20]. Although inflammation can be induced by dCGN, there are no data on human monocyte responses to dCGN exposure. Therefore, to investigate the effects of dCGN on human monocytes, normal Peripheral Blood Monocytes (PBM) and tumoral monocyte/macrophage THP-1 cells were exposed to 10 kDa and 40 kDa dCGN. We found that dCGN inhibited THP-1 cell proliferation in vitro, increased ICAM-1 expression, stimulated ICAM-1-dependent monocyte aggregation, and stimulated TNF-α expression and secretion. These responses were more pronounced after 40 kDa dCGN exposure and were linked to NF-κB activation. In addition, the 40 kDa dCGN, but not the 10 kDa dCGN induced in vivo colitis as shown by the inflammatory response in the rat colon. These results suggest that the degraded forms of CGN have an important effect on monocytes resulting in an inflammatory phenotype. Materials and Methods Preparation of Degraded Carrageenan Two preparations of degraded carrageenan with low, (∼10 kDa; C10), and medium, (∼40 kDa; C40) molecular weight were prepared from native iota-carrageenan extracted from Euchema spinosum (generously provided by Sanofi Biosystems Industry, Boulogne-Billancourt, France). Native carrageenan was dissolved in distilled water (5% w/v) under vigorous stirring and heated to 60°C. Then, the carrageenan solution was submitted to two different treatments to obtain both low and medium molecular weight fractions. Briefly, for the low molecular weight fraction, carrageenan solution was hydrolyzed with 0.3% (v/v) concentrated sulphuric acid for 15 min at 80°C. After neutralization with NaOH 4N, the solution was ultra filtered through a hollow fibre cartridge with MW cut-off 5 kDa, (Amicon Inc, Beverly, USA). For the medium molecular weight fraction, the carrageenan solution was hydrolyzed with 0.3% (v/v) concentrated sulphuric acid for 30 min at 60°C. After neutralization, the supernatant was ultra filtered (MW cut-off 100 kDa). The filtrate was submitted to a second ultra filtration (MW cut-off 5 kDa). Both preparations of dCGN were precipitated with 4 volumes of 95% ethanol, dried at room temperature and ground to small particles (1 mm in diameter). Using gel-permeation chromatography in combination with light scattering measurements (see Viebke et al. [21]), it was confirmed that the low fraction had an average molecular weight of 10 kDa, and the medium fraction of 40 kDa. The sulphate content of polysaccharides in both fractions was measured following the method of Quemener et al. [22]. Finally, the absence of polysaccharide structure modifications in the two fractions was confirmed using 2H-NMR spectroscopy. The absence of LPS contamination in the two fractions was confirmed using the e-Toxate® kit (Sigma, St Quentin Fallavier, France). Before use in cell culture, the two fractions were dissolved in complete medium during 30 min at 56°C. Animals, Chemicals and Diet Male Wistar rats (150 g average weight) were housed under standard conditions and fed ad libitum with standard rodent laboratory chow. Degraded iota-carrageenans were administered in the drinking water (5% w/v) for 55 days to 2 groups of six animals each. The first group received the low molecular weight carrageenan (10 kDa dCGN) and the second received the medium molecular weight carrageenan (40 kDa dCGN). An additional group of four rats were maintained on regular tap water (control group). To increase palatability 0.2% sucrose was added to the drinking water of all groups (Van der Waaji et al., [23]). Fresh carrageenan solutions were prepared daily. Evaluation of Colitis Body weight, liquid and food consumption, diarrhea and rectal bleeding (detected by eye inspection) were recorded throughout the feeding period. After 55 days, animals were sacrificed by cervical dislocation. The length of the colon was measured as described by Okayashu et al. [24]. Then, each colon was ligated in sections of 2 cm and 1 to 2 ml of 10% formalin was infused into the intestinal lumen. The moderately distended segment was sectioned and fixed in 10% formalin. The following day, the intestinal content was removed by vortexing. The fixed segment was kept in 10% formalin at 4°C until the paraffin embedding procedure. To evaluate the degree of inflammation, this segment of colon was opened longitudinally and macroscopic and histological scores of inflammation were recorded as previously described [25], [26]. The toluidine blue staining was used for identification of sulphated polysaccharides in the intestinal mucosa. On the day of sacrifice, a fresh sample of each colon (50 mg) was collected for myeloperoxidase (MPO) assay according to Krawisz et al., [27]. The level of MPO, mainly expressed by neutrophils, indicates the rate of recruitment of neutrophils to the intestinal mucosa. One unit of MPO activity corresponds to the degradation of 1 µmol of peroxide per minute at 25°C. Cell Culture All tissue culture reagents were from Invitrogen (Cergy Pontoise, France). THP-1 human monocytic cells were maintained in RPMI-1640 supplemented with 10% FCS, 2 mM L -glutamine, 50 U/ml penicillin and 50 mg/ml streptomycin at 37°C in a 5% CO2 incubator. Human peripheral blood mononuclear cells were obtained from heparinized blood by Ficoll-Hypaque density gradient. Monocytes were then isolated by adherence to culture flasks as described [28]. For cell aggregation, monocytes were cultured in the presence or absence of C10 or C40 for 72 h. Cell colonies were monitored under an inverted phase contrast microscope coupled through a video camera to a computer. In some wells, neutralizing monoclonal antibody to ICAM-1 (2.5 µg/ml) (Tebu, Le Perray en Yvelines, France) was added. Cell Cycle Analysis THP-1 cells in exponential growth phase were exposed to complete medium in the presence or absence of carrageenans for 24 h before being stained with propidium iodide using the DNA-Prep Coulter kit according to the manufacturer's instruction (Beckman-Coulter, Villepinte, France). Cell DNA content was then analyzed by flow cytometry using an EPICS XL2 (Beckman-Coulter). Raw data for the distribution of DNA content of 30,000 cells retrieved from the cytometer were expressed as the percentage of G0/G1 through G2/M populations. Multicycle AV software (Phoenix Flow Systems, San Diego, CA) was used to generate DNA content frequency histograms and facilitate data analysis. Cell Surface Antigen Expression Analysis Peripheral Blood Monocytes or THP-1 cells were exposed to complete medium in the presence or absence of carrageenan for 36 h. After two washes in PBS without Ca2+ and Mg2+, cells were incubated in PBS containing 0.1% gelatin and 8% AB human serum to prevent binding to Fc receptors. Then, 5×105 cells were incubated with primary antibodies at 4°C for 30 min. Two other washes in PBS preceded incubation with FITC-conjugated goat antibody anti-mouse IgG diluted 1/1000 at 4°C for 30 min (Tebu). After two additional washes, analysis of stained cells was performed on an EPICS XL2 (Beckman-Coulter). The cell population was gated according to its forward and wide-angle light scattering. Data were expressed as mean relative fluorescence intensity (MFI) of 3000 cells. TNF Activity Bioassay Monocytes or THP-1 cells were cultured with or without different concentrations of CGNs or LPS (Salmonella typhosa, Sigma) for 24 h or the indicated time. Biologically active TNF-α/β in tissue culture supernatant was measured using the WEHI 164 clone 13-cell killing assay [29]. TNF concentrations are expressed as pg/ml. RT-PCR Analysis Total RNA from monocytes was isolated using TRIzol Reagent™ (Invitrogen). cDNA was generated on 1 µg of total RNA in a reaction volume of 20 µl, using M-MLV reverse transcriptase (Invitrogen). PCR was done in the linear range of amplification (determined for each primer pair-cDNA combination). Standard PCR reactions were performed with 1 µl of the cDNA solution, 50 µM of each primer solution, 10 mM of each dNTP, 25 mM MgCl2, 10X Goldstar DNA polymerase reaction buffer, and 0.5 units of Goldstar DNA polymerase (Eurogentec, Seraing, Belgium). First PCR cycle consisted of 1 min at 92°C, 1 min at 58°C and 1 min at 72°C; then each PCR cycle consisted of 40 sec at 92°C, 40 sec at 58°C and 50 sec at 72°C. cDNA for β-actin was amplified for 28 cycles using the oligos: sense 5′-GGCATCGTGATGGACTCCG-3′ and antisense 5′GCTGGAAGGTGGACAGCGA-3′. cDNA for TNF-α was amplified for 35 cycles using the oligos: sense 5′-AAGCCTGTAGCCCATGTTGT-3′ and antisense 5′-CAGATAGATGGGCTCATACC-3′. cDNA for ICAM-1 was amplified for 35 cycles using the oligos sense 5′-GTAGCAGCCGCAGTCATAATGG-3′ and antisense 5′-A TGCTGTTGTATCTGACTGAGG-3′. NF-kB Transcription Reporter Gene Assay The plasmid 3XMHC-luc (a generous gift from Drs. J. Westwick and D.A. Brenner, University of North Carolina, Chapel Hill) contains three copies of NF-κB-responsive element from the MHC class I locus, placed upstream of the luciferase gene. Human monocytic THP-1 cells were transiently transfected as previously described [30], and then cultured for 4 h alone or with increasing concentration of either C10 or C40. Luciferase activity was determined using a luminometer (Monolight 2010 Luminometer, Ann Arbor, MI). Western Blot Analysis THP-1 cells were stimulated for various lengths of time with 0.1 mg/ml C10 or C40, or 10 µg/ml LPS. Cells were then pelleted, washed and homogenised in lysis buffer (10 mM Hepes, pH 7.9, 150 mM NaCl, 1 mM EDTA, 0.6% NP-40, and 0.5 mM PMSF) on ice. Homogenates were sonicated, centrifuged at 10,000 rpm to remove cellular debris, and supernatant collected. Protein concentration was determined using the DC Protein Assay (Bio-Rad). Proteins in samples (15 µg total proteins) were resolved in a denaturing 12% polyacrylamide gel and transferred to a nitrocellulose membrane. I-κBα protein was detected using a rabbit polyclonal antibody (Santa Cruz Biotechnology, CA) followed by a horseradish peroxidase-coupled goat polyclonal antibody against rabbit Ig (Caltag Laboratories). Finally, IκB bands were revealed using the ECL™ detection system (Amersham Pharmacia Biotech, Les Ullis, France) according to the manufacturers' instruction. Antibody to α-Tubulin (Santa Cruz) was use as loading control. For nuclear NF-κB, THP-1 cells were stimulated with 1 mg/ml C10 or C40 for 30 minutes at 37°C. Cells were then pelleted and nuclei separated as described [31]. Nuclei were washed and homogenized directly in loading (Laemli) buffer and heated for 5 minutes at 100°C. Proteins in samples were resolved in a denaturing 8% polyacrylamide gel and transferred to a polyvinylidine fluoride (PVDF) membrane (Immobilon-P; Millipore, Bedford, MA). Membranes were incubated in blocking buffer (1% BSA, in PBS) for two hours at room temperature. Membranes were subsequently probed with the corresponding antibody in blocking buffer, overnight. Rabbit polyclonal antibody anti-NF-κB p50 subunit (# sc-114) or anti-NF-κB p65 subunit (# sc-109) from Santa Cruz Biotechnology were used. Membranes were washed six times in PBS with 0.05% Tween 20, 5 minutes each time, and incubated with a 1/3000 dilution of HRP-conjugated F(ab')2 goat anti-rabbit IgG in 5% nonfat dry milk and 0.05% Tween 20 in PBS for 1 hour at room temperature. After washing six more times in PBS with 0.05% Tween 20, antibody-reactive proteins were detected using a chemiluminescence substrate (SuperSignal; Pierce, Rockford, IL) according to the manufacturer's instructions. To confirm that equivalent amounts of protein were loaded in each line, membranes were also Western blotted for ERK as described [32]. Analysis of NF-κB Activation by Flow Cytometry Nuclear activation of NF−κΒ by flow cytometry was performed as described [31]. Statistical Analysis The results were expressed as the mean value ± S.E.M. of individual experiments. The statistical significance of the differences between mean values was assessed by the Student's t-test and analysis of variance (ANOVA). Results Degraded CGN Induce Colonic Inflammation All rats developed diarrhea during degraded carrageenan administration and gross evidence of blood was frequently detected in the stools. Colon length dramatically decreased in all treated rats with a more pronounced effect being observed in the 40 kDa dCGN treated group (Fig. 1A). Furthermore, prolonged exposure to 40 kDa dCGN resulted in high macroscopic and histological scores of inflammation (Fig. 1B, C). Only weak myeloperoxidase activity was detected in both control and dCGN-treated groups (Fig. 1D), indicating that granulocytes did not play a major role in the inflammation at that stage. Histological examination revealed various degrees of mucosal inflammation. Rats treated with 10 kDa dCGN showed edema, epithelium atrophy and slight lymphocyte infiltration (data not shown). These symptoms were totally absent in the colon of control rats (Fig. 1E). More severe mucosal injuries including ulceration, hyperplastic epithelium, crypt distortion and a strong macrophage infiltration, were observed in the 40 kDa dCGN-treated rats (Fig. 1F). No sulphated polysaccharides were detected by toluidine blue staining of colon mucosa from rats treated with either the 10 or 40 kDa dCGN (not shown). Although we cannot exclude that dCGN mat not have retained in the section during the histology procedure, this indicates that these polymers may not have been phagocytosed. 10.1371/journal.pone.0008666.g001 Figure 1 Degraded CGN induced colon inflammation in rats. Histograms showing the effect of degraded CGN on: colon length (A); macroscopic (B) and histological (C) inflammation score of colon; Myeloperoxidase (MPO) activity (D). Control rats (white bars); 10 kDa degraded CGN-treated rats (grey bars); 40 kDa degraded CGN-treated rats (black bars). * p<0.05 from control. ** p<0.01 from control. Histological analysis of colon from control rats (E), and from 40 kDa dCGN-treated rats (F). Degraded CGN Induced
T63 974-983 Positive_regulation denotes increased
T64 984-990 Protein denotes ICAM-1
T65 991-1001 Gene_expression denotes expression
T66 1209-1219 Positive_regulation denotes stimulated
T67 1209-1219 Positive_regulation denotes stimulated
T68 1220-1225 Protein denotes TNF-α
T69 1226-1236 Gene_expression denotes expression
T70 1241-1250 Localization denotes secretion
T741 2769-2773 Protein denotes IL-8
T742 2774-2784 Gene_expression denotes production
T743 2839-2842 Positive_regulation denotes via
T744 4129-4138 Positive_regulation denotes increased
T745 4139-4145 Protein denotes ICAM-1
T746 4146-4156 Gene_expression denotes expression
T747 4169-4175 Protein denotes ICAM-1
T748 4212-4222 Positive_regulation denotes stimulated
T749 4212-4222 Positive_regulation denotes stimulated
T750 4223-4228 Protein denotes TNF-α
T751 4229-4239 Gene_expression denotes expression
T752 4244-4253 Localization denotes secretion
T3113 8374-8389 Protein denotes myeloperoxidase
T3114 8391-8394 Protein denotes MPO
T3115 8450-8453 Protein denotes MPO
T3116 8462-8471 Gene_expression denotes expressed
T4579 10963-10966 Protein denotes TNF
T4580 11160-11165 Protein denotes TNF-α
T4581 11166-11167 Protein denotes β
T4582 11264-11267 Protein denotes TNF
T4742 12041-12048 Protein denotes β-actin
T4743 12176-12181 Protein denotes TNF-α
T4744 12312-12318 Protein denotes ICAM-1
T5233 12708-12718 Protein denotes luciferase
T5234 12899-12909 Protein denotes Luciferase
T5474 13595-13600 Protein denotes I-κBα
T6611 16230-16245 Protein denotes myeloperoxidase
T7227 17732-17737 Protein denotes TNF-α
T7228 17738-17748 Gene_expression denotes Production
T7229 17814-17823 Positive_regulation denotes stimulate true
T7230 17824-17829 Protein denotes TNF-α
T7231 17830-17840 Gene_expression denotes production
T7232 17946-17951 Protein denotes TNF-α
T7233 17957-17964 Positive_regulation denotes induced
T7234 17978-17989 Positive_regulation denotes stimulation
T7235 18051-18059 Positive_regulation denotes resulted
T7236 18087-18095 Positive_regulation denotes increase
T7237 18099-18104 Protein denotes TNF-α
T7238 18105-18115 Gene_expression denotes production
T7239 18140-18149 Regulation denotes dependent
T7240 18262-18270 Positive_regulation denotes increase
T7241 18274-18279 Protein denotes TNF-α
T7242 18280-18290 Gene_expression denotes production
T7243 18338-18343 Protein denotes TNF-α
T7244 18344-18354 Gene_expression denotes production
T7245 18355-18364 Positive_regulation denotes increased
T7246 18459-18467 Localization denotes secreted
T7247 18468-18473 Protein denotes TNF-α
T7248 18507-18512 Protein denotes TNF-α
T7249 18579-18586 Positive_regulation denotes induced
T7250 18587-18592 Protein denotes TNF-α
T7251 18593-18603 Gene_expression denotes production
T7252 18668-18673 Protein denotes TNF-α
T7253 18674-18682 Gene_expression denotes produced
T7254 18683-18685 Positive_regulation denotes by
T7255 18719-18727 Gene_expression denotes produced
T7256 18728-18730 Positive_regulation denotes by
T7257 18900-18908 Positive_regulation denotes increase
T7258 18912-18917 Protein denotes TNF-α
T7259 18918-18928 Gene_expression denotes production
T7260 18940-18953 Positive_regulation denotes This increase
T7261 18957-18962 Protein denotes TNF-α
T7262 18963-18973 Gene_expression denotes production
T7263 19060-19065 Protein denotes TNF-α
T7264 19070-19078 Localization denotes released true
T7265 19131-19136 Protein denotes TNF-α
T7266 19137-19147 Gene_expression denotes production
T7267 19176-19185 Regulation denotes dependent true
T7268 19315-19320 Protein denotes TNF-α
T7269 19321-19328 Localization denotes release
T15842 19527-19537 Positive_regulation denotes stimulated
T15843 19538-19541 Protein denotes TNF
T15844 19542-19551 Localization denotes secretion
T15845 19578-19581 Protein denotes TNF
T15846 19582-19590 Localization denotes released
T15847 19683-19686 Protein denotes TNF
T15848 19687-19694 Localization denotes release
T15849 19695-19702 Positive_regulation denotes induced
T15850 19799-19802 Protein denotes TNF
T15851 19803-19810 Localization denotes release
T15852 19811-19818 Positive_regulation denotes induced
T15853 19972-19975 Protein denotes TNF
T15854 19976-19983 Localization denotes release
T15855 19984-19991 Positive_regulation denotes induced
T15856 20155-20158 Protein denotes TNF
T15857 20159-20166 Localization denotes release
T15858 20167-20174 Positive_regulation denotes induced
T8728 21910-21916 Protein denotes ICAM-1
T8729 21917-21927 Gene_expression denotes Expression
T8730 21931-21938 Positive_regulation denotes Induced
T8731 22318-22328 Positive_regulation denotes stimulated
T8732 22329-22339 Gene_expression denotes expression
T8733 22343-22349 Protein denotes ICAM-1
T8734 22351-22355 Protein denotes CD54
T8735 22395-22403 Positive_regulation denotes increase
T8736 22407-22413 Protein denotes ICAM-1
T8737 22414-22424 Gene_expression denotes expression
T8738 22516-22556 Protein denotes lymphocyte function-associated antigen 3
T8739 22558-22562 Protein denotes CD58
T8740 22577-22584 Negative_regulation denotes reduced
T8741 22651-22661 Gene_expression denotes expression
T8742 22770-22785 Protein denotes monocyte marker
T8743 22786-22790 Protein denotes CD14
T8744 22805-22812 Negative_regulation denotes reduced true
T16642 22967-22977 Positive_regulation denotes stimulated
T16643 22978-22984 Protein denotes ICAM-1
T16644 22985-22995 Gene_expression denotes expression
T16645 23253-23259 Protein denotes ICAM-1
T16646 23260-23270 Gene_expression denotes expression
T16647 23387-23397 Gene_expression denotes expression
T16648 23387-23397 Gene_expression denotes expression
T16649 23387-23397 Gene_expression denotes expression
T16650 23431-23435 Protein denotes CD14
T16651 23437-23443 Protein denotes ICAM-1
T16652 23449-23453 Protein denotes CD58
T8745 23884-23890 Protein denotes ICAM-1
T8746 24278-24284 Protein denotes ICAM-1
T9608 25105-25111 Positive_regulation denotes Induce
T9609 25105-25111 Positive_regulation denotes Induce
T9610 25115-25123 Positive_regulation denotes Increase
T9611 25115-25123 Positive_regulation denotes Increase
T9612 25127-25133 Protein denotes ICAM-1
T9613 25138-25143 Protein denotes TNF-α
T9614 25144-25159 Transcription denotes mRNA Expression
T9615 25144-25159 Transcription denotes mRNA Expression
T9616 25164-25172 Positive_regulation denotes increase
T9617 25164-25172 Positive_regulation denotes increase
T9618 25184-25190 Protein denotes ICAM-1
T9619 25191-25201 Gene_expression denotes expression
T9620 25206-25211 Protein denotes TNF-α
T9621 25212-25222 Gene_expression denotes production
T9622 25255-25267 Positive_regulation denotes upregulation
T9623 25255-25267 Positive_regulation denotes upregulation
T9624 25325-25332 Positive_regulation denotes induced
T9625 25325-25332 Positive_regulation denotes induced
T9626 25342-25350 Positive_regulation denotes increase
T9627 25342-25350 Positive_regulation denotes increase
T9628 25368-25374 Protein denotes ICAM-1
T9629 25379-25384 Protein denotes TNF-α
T9630 25395-25402 Protein denotes β-actin
T9631 25424-25432 Regulation denotes affected true
T17309 25509-25519 Positive_regulation denotes stimulated
T17310 25509-25519 Positive_regulation denotes stimulated
T17311 25520-25526 Protein denotes ICAM-1
T17312 25531-25536 Protein denotes TNF-α
T17313 25542-25552 Gene_expression denotes expression
T17314 25542-25552 Gene_expression denotes expression
T17315 25622-25632 Gene_expression denotes expression
T17316 25622-25632 Gene_expression denotes expression
T17317 25636-25642 Protein denotes ICAM-1
T17318 25647-25652 Protein denotes TNF-α
T17319 25712-25719 Protein denotes β-actin
T17320 25720-25730 Gene_expression denotes expression
T10028 25825-25835 Gene_expression denotes expression
T10029 25825-25835 Gene_expression denotes expression
T10030 25858-25864 Protein denotes ICAM-1
T10031 25869-25874 Protein denotes TNF-α
T10032 25878-25888 Regulation denotes controlled
T10033 25878-25888 Regulation denotes controlled
T10034 26195-26203 Positive_regulation denotes increase
T10035 26207-26217 Protein denotes luciferase
T10036 26576-26590 Protein denotes NF-κB subunits
T10037 26649-26656 Positive_regulation denotes induced
T10038 26649-26656 Positive_regulation denotes induced
T10039 26657-26667 Positive_regulation denotes activation
T10040 26657-26667 Positive_regulation denotes activation
T10041 26675-26678 Protein denotes p50
T10042 26683-26686 Protein denotes p65
T10043 27259-27266 Positive_regulation denotes induced
T10044 27259-27266 Positive_regulation denotes induced
T10045 27270-27278 Positive_regulation denotes increase
T10046 27270-27278 Positive_regulation denotes increase
T10047 27286-27289 Protein denotes p50
T10048 27294-27297 Protein denotes p65
T10049 27547-27558 Protein_catabolism denotes degradation
T10050 27566-27575 Protein denotes inhibitor
T10051 27576-27580 Protein denotes IκBα
T10052 27652-27656 Protein denotes IκBα
T10053 27657-27668 Protein_catabolism denotes degradation true
T10054 27722-27726 Protein denotes IκBα
T10055 27740-27748 Protein_catabolism denotes degraded
T10056 27806-27810 Protein denotes IκBα
T10057 27829-27834 Negative_regulation denotes masks
T10058 27839-27868 Entity denotes nuclear localisation sequence
T10059 27872-27875 Protein denotes p65
T10060 27900-27908 Protein_catabolism denotes degraded
T17517 28104-28111 Positive_regulation denotes driving true
T17518 28112-28122 Gene_expression denotes expression
T17519 28126-28136 Protein denotes luciferase
T17520 28457-28461 Protein denotes IκBα
T17521 28826-28829 Protein denotes p50
T17522 28839-28842 Protein denotes p50
T17523 28853-28856 Protein denotes p65
T17524 28866-28869 Protein denotes p65
T17525 29158-29161 Protein denotes p50
T17526 29179-29182 Protein denotes p65
T11468 32550-32560 Gene_expression denotes production
T11469 32564-32567 Protein denotes TNF
T11470 32596-32610 Positive_regulation denotes in response to
T11471 32630-32637 Positive_regulation denotes induced
T11472 32647-32657 Gene_expression denotes production
T11473 32661-32664 Protein denotes TNF
T11474 32825-32832 Gene_expression denotes produce
T11475 32833-32836 Protein denotes TNF
T11476 33104-33107 Protein denotes TNF
T11477 33108-33116 Localization denotes secreted
T11478 33124-33131 Positive_regulation denotes induced
T11479 33170-33178 Localization denotes secreted
T11480 33255-33263 Localization denotes presence
T11481 33255-33263 Localization denotes presence
T11482 33271-33275 Protein denotes CD14
T11483 33280-33294 Protein denotes TLR4 receptors
T11484 33368-33378 Gene_expression denotes expression
T11485 33368-33378 Gene_expression denotes expression
T11486 33422-33426 Protein denotes CD14
T11487 33434-33443 Gene_expression denotes expressed true
T11488 33474-33483 Gene_expression denotes expressed
T11489 33628-33635 Positive_regulation denotes induced
T11490 33636-33639 Protein denotes TNF
T11491 33640-33649 Localization denotes secretion
T11492 33663-33666 Protein denotes TNF
T11493 33667-33675 Regulation denotes response
T11494 33731-33739 Negative_regulation denotes decrease
T11495 33851-33854 Protein denotes TNF
T11496 33855-33863 Localization denotes secreted
T11497 33877-33884 Positive_regulation denotes induced
T11498 33999-34002 Protein denotes TNF
T11499 34003-34012 Localization denotes secretion
T11500 34196-34205 Negative_regulation denotes inhibited
T11501 34211-34218 Positive_regulation denotes induced
T11502 34219-34222 Protein denotes TNF
T11503 34223-34232 Localization denotes secretion
T11504 34246-34250 Protein denotes TLR4
T11505 34302-34310 Protein denotes receptor
T11506 34385-34389 Protein denotes TLR4
T11507 34393-34402 Positive_regulation denotes activated
T11508 34481-34485 Protein denotes TLR4
T11509 34704-34714 Gene_expression denotes expression
T11510 34722-34739 Protein denotes adhesion molecule
T11511 34740-34746 Protein denotes ICAM-1
T11512 34751-34759 Positive_regulation denotes enhanced
T11513 34798-34808 Gene_expression denotes expression
T11514 34812-34818 Protein denotes ICAM-1
T11515 34972-34982 Gene_expression denotes expression
T11516 34986-34992 Protein denotes ICAM-1
T11517 34993-35000 Positive_regulation denotes induced
T11518 35363-35372 Positive_regulation denotes increased
T11519 35363-35372 Positive_regulation denotes increased
T11520 35373-35383 Gene_expression denotes expression
T11521 35373-35383 Gene_expression denotes expression
T11522 35394-35400 Protein denotes ICAM-1
T11523 35405-35410 Protein denotes LFA-3
T11524 35412-35416 Protein denotes CD58
T11525 35550-35557 Gene_expression denotes express
T11526 35561-35570 Positive_regulation denotes increased
T11527 35581-35587 Protein denotes ICAM-1
T11528 35588-35606 Protein denotes adhesion molecules
T11529 35779-35788 Regulation denotes regulates
T11530 35779-35788 Regulation denotes regulates
T11531 35795-35806 Regulation denotes responsible
T11532 35795-35806 Regulation denotes responsible
T11533 35811-35817 Protein denotes ICAM-1
T11534 35822-35827 Protein denotes TNF-α
T11535 35828-35838 Gene_expression denotes expression
T11536 35828-35838 Gene_expression denotes expression
T11537 35977-35988 Protein_catabolism denotes degradation
T11538 35992-35996 Protein denotes IκBα
T11539 35998-36011 Localization denotes translocation
T11540 35998-36011 Localization denotes translocation
T11541 36015-36018 Protein denotes p65
T11542 36023-36026 Protein denotes p50
T11543 36044-36051 Entity denotes nucleus
T11544 36059-36069 Positive_regulation denotes activation
T11545 36082-36092 Regulation denotes responsive
T11546 36093-36103 Protein denotes luciferase
T11547 36796-36806 Negative_regulation denotes suppressed
T11548 36807-36811 Protein denotes cdk4
T11549 36812-36822 Gene_expression denotes expression
T11550 37010-37013 Protein denotes p21
T11551 37024-37031 Regulation denotes effects true
T11552 37024-37031 Regulation denotes effects true
T11553 37043-37046 Protein denotes p21
T11554 37051-37055 Protein denotes cdk4
T11555 37056-37066 Gene_expression denotes expression
T11556 37056-37066 Gene_expression denotes expression
T11557 37241-37247 Positive_regulation denotes higher
T11558 37241-37247 Positive_regulation denotes higher
T11559 37248-37258 Gene_expression denotes expression
T11560 37284-37290 Protein denotes ICAM-1
T11561 37295-37300 Protein denotes TNF-α
T11562 37301-37311 Gene_expression denotes production
T11563 37341-37347 Positive_regulation denotes higher
T11564 37348-37358 Gene_expression denotes expression
T11565 37362-37368 Protein denotes ICAM-1
T11566 37536-37542 Positive_regulation denotes induce
T11567 38200-38209 Positive_regulation denotes increased
T11568 38210-38216 Protein denotes ICAM-1
T11569 38217-38227 Gene_expression denotes expression
T11570 38240-38246 Protein denotes ICAM-1
T11571 38292-38302 Positive_regulation denotes stimulated
T11572 38292-38302 Positive_regulation denotes stimulated
T11573 38303-38308 Protein denotes TNF-α
T11574 38309-38319 Gene_expression denotes expression
T11575 38324-38333 Localization denotes secretion
R13579 T15843 T15844 themeOf TNF,secretion
R13580 T15844 T15842 themeOf secretion,stimulated
R13581 T15845 T15846 themeOf TNF,released
R13582 T15847 T15848 themeOf TNF,release
R13583 T15848 T15849 themeOf release,induced
R13584 T15850 T15851 themeOf TNF,release
R13585 T15851 T15852 themeOf release,induced
R13586 T15853 T15854 themeOf TNF,release
R13587 T15854 T15855 themeOf release,induced
R13588 T15856 T15857 themeOf TNF,release
R13589 T15857 T15858 themeOf release,induced
R14262 T16643 T16644 themeOf ICAM-1,expression
R14263 T16644 T16642 themeOf expression,stimulated
R14264 T16645 T16646 themeOf ICAM-1,expression
R14265 T16650 T16648 themeOf CD14,expression
R14266 T16651 T16647 themeOf ICAM-1,expression
R14267 T16652 T16649 themeOf CD58,expression
R14821 T17311 T17314 themeOf ICAM-1,expression
R14822 T17312 T17313 themeOf TNF-α,expression
R14823 T17313 T17310 themeOf expression,stimulated
R14824 T17314 T17309 themeOf expression,stimulated
R14825 T17317 T17315 themeOf ICAM-1,expression
R14826 T17318 T17316 themeOf TNF-α,expression
R14827 T17319 T17320 themeOf β-actin,expression
R14948 T17518 T17517 themeOf expression,driving
R14949 T17519 T17518 themeOf luciferase,expression
R14950 T17522 T17521 equivalentTo p50,p50
R14951 T17524 T17523 equivalentTo p65,p65
R22 T64 T65 themeOf ICAM-1,expression
R23 T65 T63 themeOf expression,increased
R24 T68 T69 themeOf TNF-α,expression
R25 T68 T70 themeOf TNF-α,secretion
R26 T69 T67 themeOf expression,stimulated
R27 T70 T66 themeOf secretion,stimulated
R2770 T3114 T3113 equivalentTo MPO,myeloperoxidase
R2771 T3115 T3116 themeOf MPO,expressed
R549 T53 T59 themeOf Induces,through
R550 T54 T60 themeOf Induces,through
R551 T55 T56 themeOf TNF,Secretion
R552 T56 T53 themeOf Secretion,Induces
R553 T57 T58 themeOf ICAM-1,Upregulation
R554 T58 T54 themeOf Upregulation,Induces
R571 T741 T742 themeOf IL-8,production
R572 T742 T743 themeOf production,via
R573 T745 T746 themeOf ICAM-1,expression
R574 T746 T744 themeOf expression,increased
R575 T750 T751 themeOf TNF-α,expression
R576 T750 T752 themeOf TNF-α,secretion
R577 T751 T748 themeOf expression,stimulated
R578 T752 T749 themeOf secretion,stimulated
R6412 T7227 T7228 themeOf TNF-α,Production
R6413 T7228 T7226 themeOf Production,"inhibited THP-1 cell proliferation in vitro, arresting the cells in G1 phase. In addition, dCGN increased ICAM-1 expression in both PBM and THP-1 cells with a major effect seen after 40 kDa dCGN exposure. Also, dCGN stimulated monocyte aggregation in vitro that was prevented by incubation with anti-ICAM-1 antibody. Finally, dCGN stimulated TNF-α expression and secretion by both PBM and THP-1 cells. All these effects were linked to NF-κB activation. These data strongly suggest that the degraded forms of CGN have a pronounced effect on monocytes, characteristic of an inflammatory phenotype. Introduction Carrageenan (CGN) is a high molecular weight sulphated polysaccharide (>200 kDa) derived from red algae (Rhodophyceae). Three main forms of CGN have been identified: kappa, iota, and lambda. They differ from each other in sulphation degree and solubility [1], [2]. Native CGN is thought to be harmless and is widely used as a food additive to improve texture. It is also used in cosmetics and pharmaceuticals. However, acid treatment at high temperature (80°C) triggers CGN hydrolysis to lower molecular weight (<50 kDa) compounds known as poligeenan or degraded CGN (dCGN). These dCGNs induce inflammation and have been widely used as models of colitis in several species, including rats [3], rabbits [4] and guinea pigs [5]. The role of dCGN as a tumor-promoting factor remains controversial [4], [6]–[8]. Although the native form is thought to be harmless for human consumption, small amounts of dCGN are probably produced by acid hydrolysis during gastric digestion [9], [10] or interaction with intestinal bacteria [11], [12]. Whereas the effects of native and dCGN on intestinal inflammation have been extensively analyzed in animal models, only few studies have been conducted using human cell lines. Recent studies have shown a link between exposure to native form CGN and IL-8 production by the human intestinal epithelial cell line, NCM460, via Nuclear Factor-κB (NF-κB) activation [13], [14]. NF-κB is a transcription factor that regulates the expression of genes associated with inflammation [15], [16]. Macrophage infiltration and accumulation is a common characteristic of intestinal diseases [17]. Macrophages represent 10% of total lamina propria cells, secrete a wide range of biologically active compounds and express cell-adhesion molecules. The immune cell response to an inflammatory stimulus seems to be amplified or directly generated by cells exposed to sulphated polysaccharides such as carrageenans. Indeed, inflammation induced by dCGN was associated with recruitment of macrophages to inflammation sites [18], [19]. Also, inflammation induced by Dextran Sulphate Sodium (DSS), another sulphated compound, was directly associated with macrophages recruitment [20], since DSS still provoked inflammation after T-lymphocyte and NK cell depletion [20]. Although inflammation can be induced by dCGN, there are no data on human monocyte responses to dCGN exposure. Therefore, to investigate the effects of dCGN on human monocytes, normal Peripheral Blood Monocytes (PBM) and tumoral monocyte/macrophage THP-1 cells were exposed to 10 kDa and 40 kDa dCGN. We found that dCGN inhibited THP-1 cell proliferation in vitro, increased ICAM-1 expression, stimulated ICAM-1-dependent monocyte aggregation, and stimulated TNF-α expression and secretion. These responses were more pronounced after 40 kDa dCGN exposure and were linked to NF-κB activation. In addition, the 40 kDa dCGN, but not the 10 kDa dCGN induced in vivo colitis as shown by the inflammatory response in the rat colon. These results suggest that the degraded forms of CGN have an important effect on monocytes resulting in an inflammatory phenotype. Materials and Methods Preparation of Degraded Carrageenan Two preparations of degraded carrageenan with low, (∼10 kDa; C10), and medium, (∼40 kDa; C40) molecular weight were prepared from native iota-carrageenan extracted from Euchema spinosum (generously provided by Sanofi Biosystems Industry, Boulogne-Billancourt, France). Native carrageenan was dissolved in distilled water (5% w/v) under vigorous stirring and heated to 60°C. Then, the carrageenan solution was submitted to two different treatments to obtain both low and medium molecular weight fractions. Briefly, for the low molecular weight fraction, carrageenan solution was hydrolyzed with 0.3% (v/v) concentrated sulphuric acid for 15 min at 80°C. After neutralization with NaOH 4N, the solution was ultra filtered through a hollow fibre cartridge with MW cut-off 5 kDa, (Amicon Inc, Beverly, USA). For the medium molecular weight fraction, the carrageenan solution was hydrolyzed with 0.3% (v/v) concentrated sulphuric acid for 30 min at 60°C. After neutralization, the supernatant was ultra filtered (MW cut-off 100 kDa). The filtrate was submitted to a second ultra filtration (MW cut-off 5 kDa). Both preparations of dCGN were precipitated with 4 volumes of 95% ethanol, dried at room temperature and ground to small particles (1 mm in diameter). Using gel-permeation chromatography in combination with light scattering measurements (see Viebke et al. [21]), it was confirmed that the low fraction had an average molecular weight of 10 kDa, and the medium fraction of 40 kDa. The sulphate content of polysaccharides in both fractions was measured following the method of Quemener et al. [22]. Finally, the absence of polysaccharide structure modifications in the two fractions was confirmed using 2H-NMR spectroscopy. The absence of LPS contamination in the two fractions was confirmed using the e-Toxate® kit (Sigma, St Quentin Fallavier, France). Before use in cell culture, the two fractions were dissolved in complete medium during 30 min at 56°C. Animals, Chemicals and Diet Male Wistar rats (150 g average weight) were housed under standard conditions and fed ad libitum with standard rodent laboratory chow. Degraded iota-carrageenans were administered in the drinking water (5% w/v) for 55 days to 2 groups of six animals each. The first group received the low molecular weight carrageenan (10 kDa dCGN) and the second received the medium molecular weight carrageenan (40 kDa dCGN). An additional group of four rats were maintained on regular tap water (control group). To increase palatability 0.2% sucrose was added to the drinking water of all groups (Van der Waaji et al., [23]). Fresh carrageenan solutions were prepared daily. Evaluation of Colitis Body weight, liquid and food consumption, diarrhea and rectal bleeding (detected by eye inspection) were recorded throughout the feeding period. After 55 days, animals were sacrificed by cervical dislocation. The length of the colon was measured as described by Okayashu et al. [24]. Then, each colon was ligated in sections of 2 cm and 1 to 2 ml of 10% formalin was infused into the intestinal lumen. The moderately distended segment was sectioned and fixed in 10% formalin. The following day, the intestinal content was removed by vortexing. The fixed segment was kept in 10% formalin at 4°C until the paraffin embedding procedure. To evaluate the degree of inflammation, this segment of colon was opened longitudinally and macroscopic and histological scores of inflammation were recorded as previously described [25], [26]. The toluidine blue staining was used for identification of sulphated polysaccharides in the intestinal mucosa. On the day of sacrifice, a fresh sample of each colon (50 mg) was collected for myeloperoxidase (MPO) assay according to Krawisz et al., [27]. The level of MPO, mainly expressed by neutrophils, indicates the rate of recruitment of neutrophils to the intestinal mucosa. One unit of MPO activity corresponds to the degradation of 1 µmol of peroxide per minute at 25°C. Cell Culture All tissue culture reagents were from Invitrogen (Cergy Pontoise, France). THP-1 human monocytic cells were maintained in RPMI-1640 supplemented with 10% FCS, 2 mM L -glutamine, 50 U/ml penicillin and 50 mg/ml streptomycin at 37°C in a 5% CO2 incubator. Human peripheral blood mononuclear cells were obtained from heparinized blood by Ficoll-Hypaque density gradient. Monocytes were then isolated by adherence to culture flasks as described [28]. For cell aggregation, monocytes were cultured in the presence or absence of C10 or C40 for 72 h. Cell colonies were monitored under an inverted phase contrast microscope coupled through a video camera to a computer. In some wells, neutralizing monoclonal antibody to ICAM-1 (2.5 µg/ml) (Tebu, Le Perray en Yvelines, France) was added. Cell Cycle Analysis THP-1 cells in exponential growth phase were exposed to complete medium in the presence or absence of carrageenans for 24 h before being stained with propidium iodide using the DNA-Prep Coulter kit according to the manufacturer's instruction (Beckman-Coulter, Villepinte, France). Cell DNA content was then analyzed by flow cytometry using an EPICS XL2 (Beckman-Coulter). Raw data for the distribution of DNA content of 30,000 cells retrieved from the cytometer were expressed as the percentage of G0/G1 through G2/M populations. Multicycle AV software (Phoenix Flow Systems, San Diego, CA) was used to generate DNA content frequency histograms and facilitate data analysis. Cell Surface Antigen Expression Analysis Peripheral Blood Monocytes or THP-1 cells were exposed to complete medium in the presence or absence of carrageenan for 36 h. After two washes in PBS without Ca2+ and Mg2+, cells were incubated in PBS containing 0.1% gelatin and 8% AB human serum to prevent binding to Fc receptors. Then, 5×105 cells were incubated with primary antibodies at 4°C for 30 min. Two other washes in PBS preceded incubation with FITC-conjugated goat antibody anti-mouse IgG diluted 1/1000 at 4°C for 30 min (Tebu). After two additional washes, analysis of stained cells was performed on an EPICS XL2 (Beckman-Coulter). The cell population was gated according to its forward and wide-angle light scattering. Data were expressed as mean relative fluorescence intensity (MFI) of 3000 cells. TNF Activity Bioassay Monocytes or THP-1 cells were cultured with or without different concentrations of CGNs or LPS (Salmonella typhosa, Sigma) for 24 h or the indicated time. Biologically active TNF-α/β in tissue culture supernatant was measured using the WEHI 164 clone 13-cell killing assay [29]. TNF concentrations are expressed as pg/ml. RT-PCR Analysis Total RNA from monocytes was isolated using TRIzol Reagent™ (Invitrogen). cDNA was generated on 1 µg of total RNA in a reaction volume of 20 µl, using M-MLV reverse transcriptase (Invitrogen). PCR was done in the linear range of amplification (determined for each primer pair-cDNA combination). Standard PCR reactions were performed with 1 µl of the cDNA solution, 50 µM of each primer solution, 10 mM of each dNTP, 25 mM MgCl2, 10X Goldstar DNA polymerase reaction buffer, and 0.5 units of Goldstar DNA polymerase (Eurogentec, Seraing, Belgium). First PCR cycle consisted of 1 min at 92°C, 1 min at 58°C and 1 min at 72°C; then each PCR cycle consisted of 40 sec at 92°C, 40 sec at 58°C and 50 sec at 72°C. cDNA for β-actin was amplified for 28 cycles using the oligos: sense 5′-GGCATCGTGATGGACTCCG-3′ and antisense 5′GCTGGAAGGTGGACAGCGA-3′. cDNA for TNF-α was amplified for 35 cycles using the oligos: sense 5′-AAGCCTGTAGCCCATGTTGT-3′ and antisense 5′-CAGATAGATGGGCTCATACC-3′. cDNA for ICAM-1 was amplified for 35 cycles using the oligos sense 5′-GTAGCAGCCGCAGTCATAATGG-3′ and antisense 5′-A TGCTGTTGTATCTGACTGAGG-3′. NF-kB Transcription Reporter Gene Assay The plasmid 3XMHC-luc (a generous gift from Drs. J. Westwick and D.A. Brenner, University of North Carolina, Chapel Hill) contains three copies of NF-κB-responsive element from the MHC class I locus, placed upstream of the luciferase gene. Human monocytic THP-1 cells were transiently transfected as previously described [30], and then cultured for 4 h alone or with increasing concentration of either C10 or C40. Luciferase activity was determined using a luminometer (Monolight 2010 Luminometer, Ann Arbor, MI). Western Blot Analysis THP-1 cells were stimulated for various lengths of time with 0.1 mg/ml C10 or C40, or 10 µg/ml LPS. Cells were then pelleted, washed and homogenised in lysis buffer (10 mM Hepes, pH 7.9, 150 mM NaCl, 1 mM EDTA, 0.6% NP-40, and 0.5 mM PMSF) on ice. Homogenates were sonicated, centrifuged at 10,000 rpm to remove cellular debris, and supernatant collected. Protein concentration was determined using the DC Protein Assay (Bio-Rad). Proteins in samples (15 µg total proteins) were resolved in a denaturing 12% polyacrylamide gel and transferred to a nitrocellulose membrane. I-κBα protein was detected using a rabbit polyclonal antibody (Santa Cruz Biotechnology, CA) followed by a horseradish peroxidase-coupled goat polyclonal antibody against rabbit Ig (Caltag Laboratories). Finally, IκB bands were revealed using the ECL™ detection system (Amersham Pharmacia Biotech, Les Ullis, France) according to the manufacturers' instruction. Antibody to α-Tubulin (Santa Cruz) was use as loading control. For nuclear NF-κB, THP-1 cells were stimulated with 1 mg/ml C10 or C40 for 30 minutes at 37°C. Cells were then pelleted and nuclei separated as described [31]. Nuclei were washed and homogenized directly in loading (Laemli) buffer and heated for 5 minutes at 100°C. Proteins in samples were resolved in a denaturing 8% polyacrylamide gel and transferred to a polyvinylidine fluoride (PVDF) membrane (Immobilon-P; Millipore, Bedford, MA). Membranes were incubated in blocking buffer (1% BSA, in PBS) for two hours at room temperature. Membranes were subsequently probed with the corresponding antibody in blocking buffer, overnight. Rabbit polyclonal antibody anti-NF-κB p50 subunit (# sc-114) or anti-NF-κB p65 subunit (# sc-109) from Santa Cruz Biotechnology were used. Membranes were washed six times in PBS with 0.05% Tween 20, 5 minutes each time, and incubated with a 1/3000 dilution of HRP-conjugated F(ab')2 goat anti-rabbit IgG in 5% nonfat dry milk and 0.05% Tween 20 in PBS for 1 hour at room temperature. After washing six more times in PBS with 0.05% Tween 20, antibody-reactive proteins were detected using a chemiluminescence substrate (SuperSignal; Pierce, Rockford, IL) according to the manufacturer's instructions. To confirm that equivalent amounts of protein were loaded in each line, membranes were also Western blotted for ERK as described [32]. Analysis of NF-κB Activation by Flow Cytometry Nuclear activation of NF−κΒ by flow cytometry was performed as described [31]. Statistical Analysis The results were expressed as the mean value ± S.E.M. of individual experiments. The statistical significance of the differences between mean values was assessed by the Student's t-test and analysis of variance (ANOVA). Results Degraded CGN Induce Colonic Inflammation All rats developed diarrhea during degraded carrageenan administration and gross evidence of blood was frequently detected in the stools. Colon length dramatically decreased in all treated rats with a more pronounced effect being observed in the 40 kDa dCGN treated group (Fig. 1A). Furthermore, prolonged exposure to 40 kDa dCGN resulted in high macroscopic and histological scores of inflammation (Fig. 1B, C). Only weak myeloperoxidase activity was detected in both control and dCGN-treated groups (Fig. 1D), indicating that granulocytes did not play a major role in the inflammation at that stage. Histological examination revealed various degrees of mucosal inflammation. Rats treated with 10 kDa dCGN showed edema, epithelium atrophy and slight lymphocyte infiltration (data not shown). These symptoms were totally absent in the colon of control rats (Fig. 1E). More severe mucosal injuries including ulceration, hyperplastic epithelium, crypt distortion and a strong macrophage infiltration, were observed in the 40 kDa dCGN-treated rats (Fig. 1F). No sulphated polysaccharides were detected by toluidine blue staining of colon mucosa from rats treated with either the 10 or 40 kDa dCGN (not shown). Although we cannot exclude that dCGN mat not have retained in the section during the histology procedure, this indicates that these polymers may not have been phagocytosed. 10.1371/journal.pone.0008666.g001 Figure 1 Degraded CGN induced colon inflammation in rats. Histograms showing the effect of degraded CGN on: colon length (A); macroscopic (B) and histological (C) inflammation score of colon; Myeloperoxidase (MPO) activity (D). Control rats (white bars); 10 kDa degraded CGN-treated rats (grey bars); 40 kDa degraded CGN-treated rats (black bars). * p<0.05 from control. ** p<0.01 from control. Histological analysis of colon from control rats (E), and from 40 kDa dCGN-treated rats (F). Degraded CGN Induced"
R6414 T7230 T7231 themeOf TNF-α,production
R6415 T7231 T7229 themeOf production,stimulate
R6416 T7232 T7233 themeOf TNF-α,induced
R6417 T7233 T7234 themeOf induced,stimulation
R6418 T7235 T7239 themeOf resulted,dependent
R6419 T7236 T7235 themeOf increase,resulted
R6420 T7237 T7238 themeOf TNF-α,production
R6421 T7238 T7236 themeOf production,increase
R6422 T7241 T7242 themeOf TNF-α,production
R6423 T7242 T7240 themeOf production,increase
R6424 T7243 T7244 themeOf TNF-α,production
R6425 T7244 T7245 themeOf production,increased
R6426 T7247 T7246 themeOf TNF-α,secreted
R6427 T7250 T7251 themeOf TNF-α,production
R6428 T7251 T7249 themeOf production,induced
R6429 T7252 T7253 themeOf TNF-α,produced
R6430 T7252 T7255 themeOf TNF-α,produced
R6431 T7253 T7254 themeOf produced,by
R6432 T7255 T7256 themeOf produced,by
R6433 T7258 T7259 themeOf TNF-α,production
R6434 T7259 T7257 themeOf production,increase
R6435 T7261 T7262 themeOf TNF-α,production
R6436 T7262 T7260 themeOf production,This increase
R6437 T7263 T7264 themeOf TNF-α,released
R6438 T7265 T7266 themeOf TNF-α,production
R6439 T7266 T7267 themeOf production,dependent
R6440 T7268 T7269 themeOf TNF-α,release
R7674 T8728 T8729 themeOf ICAM-1,Expression
R7675 T8729 T8730 themeOf Expression,Induced
R7676 T8732 T8731 themeOf expression,stimulated
R7677 T8733 T8732 themeOf ICAM-1,expression
R7678 T8734 T8733 equivalentTo CD54,ICAM-1
R7679 T8736 T8737 themeOf ICAM-1,expression
R7680 T8737 T8735 themeOf expression,increase
R7681 T8738 T8740 themeOf lymphocyte function-associated antigen 3,reduced
R7682 T8739 T8738 equivalentTo CD58,lymphocyte function-associated antigen 3
R7683 T8741 T8744 themeOf expression,reduced
R7684 T8743 T8741 themeOf CD14,expression
R8429 T9610 T9608 themeOf Increase,Induce
R8430 T9611 T9609 themeOf Increase,Induce
R8431 T9612 T9614 themeOf ICAM-1,mRNA Expression
R8432 T9613 T9615 themeOf TNF-α,mRNA Expression
R8433 T9614 T9610 themeOf mRNA Expression,Increase
R8434 T9615 T9611 themeOf mRNA Expression,Increase
R8435 T9618 T9619 themeOf ICAM-1,expression
R8436 T9618 T9623 themeOf ICAM-1,upregulation
R8437 T9619 T9617 themeOf expression,increase
R8438 T9620 T9621 themeOf TNF-α,production
R8439 T9620 T9622 themeOf TNF-α,upregulation
R8440 T9621 T9616 themeOf production,increase
R8441 T9626 T9625 themeOf increase,induced
R8442 T9627 T9624 themeOf increase,induced
R8443 T9628 T9627 themeOf ICAM-1,increase
R8444 T9629 T9626 themeOf TNF-α,increase
R8445 T9630 T9631 themeOf β-actin,affected
R8670 T10028 T10033 themeOf expression,controlled
R8671 T10029 T10032 themeOf expression,controlled
R8672 T10030 T10029 themeOf ICAM-1,expression
R8673 T10031 T10028 themeOf TNF-α,expression
R8674 T10035 T10034 themeOf luciferase,increase
R8675 T10039 T10037 themeOf activation,induced
R8676 T10040 T10038 themeOf activation,induced
R8677 T10041 T10040 themeOf p50,activation
R8678 T10042 T10039 themeOf p65,activation
R8679 T10045 T10044 themeOf increase,induced
R8680 T10046 T10043 themeOf increase,induced
R8681 T10047 T10046 themeOf p50,increase
R8682 T10048 T10045 themeOf p65,increase
R8683 T10051 T10049 themeOf IκBα,degradation
R8684 T10052 T10053 themeOf IκBα,degradation
R8685 T10054 T10055 themeOf IκBα,degraded
R8686 T10056 T10057 causeOf IκBα,masks
R8687 T10056 T10060 themeOf IκBα,degraded
R8688 T10058 T10057 themeOf nuclear localisation sequence,masks
R8689 T10058 T10059 partOf nuclear localisation sequence,p65
R9721 T11468 T11470 themeOf production,in response to
R9722 T11469 T11468 themeOf TNF,production
R9723 T11472 T11471 themeOf production,induced
R9724 T11473 T11472 themeOf TNF,production
R9725 T11475 T11474 themeOf TNF,produce
R9726 T11476 T11477 themeOf TNF,secreted
R9727 T11476 T11479 themeOf TNF,secreted
R9728 T11477 T11478 themeOf secreted,induced
R9729 T11482 T11480 themeOf CD14,presence
R9730 T11482 T11485 themeOf CD14,expression
R9731 T11483 T11481 themeOf TLR4 receptors,presence
R9732 T11483 T11484 themeOf TLR4 receptors,expression
R9733 T11486 T11487 themeOf CD14,expressed
R9734 T11486 T11488 themeOf CD14,expressed
R9735 T11490 T11491 themeOf TNF,secretion
R9736 T11491 T11489 themeOf secretion,induced
R9737 T11492 T11493 themeOf TNF,response
R9738 T11493 T11494 themeOf response,decrease
R9739 T11495 T11496 themeOf TNF,secreted
R9740 T11496 T11497 themeOf secreted,induced
R9741 T11498 T11499 themeOf TNF,secretion
R9742 T11501 T11500 themeOf induced,inhibited
R9743 T11502 T11503 themeOf TNF,secretion
R9744 T11503 T11501 themeOf secretion,induced
R9745 T11506 T11507 themeOf TLR4,activated
R9746 T11509 T11512 themeOf expression,enhanced
R9747 T11511 T11509 themeOf ICAM-1,expression
R9748 T11514 T11513 themeOf ICAM-1,expression
R9749 T11515 T11517 themeOf expression,induced
R9750 T11516 T11515 themeOf ICAM-1,expression
R9751 T11520 T11518 themeOf expression,increased
R9752 T11521 T11519 themeOf expression,increased
R9753 T11522 T11521 themeOf ICAM-1,expression
R9754 T11523 T11520 themeOf LFA-3,expression
R9755 T11524 T11523 equivalentTo CD58,LFA-3
R9756 T11525 T11526 themeOf express,increased
R9757 T11527 T11525 themeOf ICAM-1,express
R9758 T11531 T11529 themeOf responsible,regulates
R9759 T11532 T11530 themeOf responsible,regulates
R9760 T11533 T11536 themeOf ICAM-1,expression
R9761 T11534 T11535 themeOf TNF-α,expression
R9762 T11535 T11532 themeOf expression,responsible
R9763 T11536 T11531 themeOf expression,responsible
R9764 T11538 T11537 themeOf IκBα,degradation
R9765 T11541 T11540 themeOf p65,translocation
R9766 T11542 T11539 themeOf p50,translocation
R9767 T11543 T11540 locationOf nucleus,translocation
R9768 T11543 T11539 locationOf nucleus,translocation
R9769 T11545 T11544 themeOf responsive,activation
R9770 T11546 T11545 themeOf luciferase,responsive
R9771 T11548 T11549 themeOf cdk4,expression
R9772 T11549 T11547 themeOf expression,suppressed
R9773 T11553 T11556 themeOf p21,expression
R9774 T11554 T11555 themeOf cdk4,expression
R9775 T11555 T11551 themeOf expression,effects
R9776 T11556 T11552 themeOf expression,effects
R9777 T11559 T11558 themeOf expression,higher
R9778 T11560 T11559 themeOf ICAM-1,expression
R9779 T11561 T11562 themeOf TNF-α,production
R9780 T11562 T11557 themeOf production,higher
R9781 T11563 T11566 themeOf higher,induce
R9782 T11564 T11563 themeOf expression,higher
R9783 T11565 T11564 themeOf ICAM-1,expression
R9784 T11568 T11569 themeOf ICAM-1,expression
R9785 T11569 T11567 themeOf expression,increased
R9786 T11573 T11574 themeOf TNF-α,expression
R9787 T11573 T11575 themeOf TNF-α,secretion
R9788 T11574 T11572 themeOf expression,stimulated
R9789 T11575 T11571 themeOf secretion,stimulated