PMC:2800179 JSONTXT 21 Projects

Annnotations TAB TSV DIC JSON TextAE

Id Subject Object Predicate Lexical cue
T667 45-52 Positive_regulation denotes Induces
T668 45-52 Positive_regulation denotes Induces
T662 53-56 Protein denotes TNF
T664 57-66 Localization denotes Secretion
T665 78-90 Positive_regulation denotes Upregulation
T663 112-117 Protein denotes NF-κB
T666 118-128 Positive_regulation denotes Activation
T669 655-679 Protein denotes ICAM-1 adhesion molecule
T8186 865-873 Protein_catabolism denotes Degraded
T8185 874-17737 Protein denotes CGN 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-TNF-α
T672 974-983 Positive_regulation denotes increased
T670 984-990 Protein denotes ICAM-1
T671 991-1001 Gene_expression denotes expression
T673 1089-1093 Protein denotes dCGN
T674 1173-1193 Protein denotes anti-ICAM-1 antibody
T675 1204-1208 Protein denotes dCGN
T678 1209-1219 Positive_regulation denotes stimulated
T676 1220-1225 Protein denotes TNF-α
T677 1226-1236 Gene_expression denotes expression
T679 1313-1318 Protein denotes NF-κB
T680 1319-1329 Positive_regulation denotes activation
T682 1368-1376 Protein_catabolism denotes degraded
T681 1386-1389 Protein denotes CGN
T2034 2843-2860 Protein denotes Nuclear Factor-κB
T2035 2862-2867 Protein denotes NF-κB
T2036 2869-2879 Positive_regulation denotes activation
T2037 2869-2879 Positive_regulation denotes activation
T2038 2892-2897 Protein denotes NF-κB
T2039 2929-2938 Regulation denotes regulates
T2045 4129-4138 Positive_regulation denotes increased
T2040 4139-4145 Protein denotes ICAM-1
T2043 4146-4156 Gene_expression denotes expression
T2041 4169-4175 Protein denotes ICAM-1
T2046 4212-4222 Positive_regulation denotes stimulated
T2042 4223-4228 Protein denotes TNF-α
T2044 4229-4239 Gene_expression denotes expression
T2047 4338-4343 Protein denotes NF-κB
T2048 4344-4354 Positive_regulation denotes activation
T2050 4521-4529 Protein_catabolism denotes degraded
T2049 4539-4542 Protein denotes CGN
T2808 6501-6506 Protein denotes Sigma
T2809 6508-6518 Protein denotes St Quentin
T3658 8360-8369 Positive_regulation denotes collected
T3659 8360-8369 Positive_regulation denotes collected
T3656 8374-8389 Protein denotes myeloperoxidase
T3657 8391-8394 Protein denotes MPO
T3660 8450-8453 Protein denotes MPO
T3661 8462-8471 Gene_expression denotes expressed
T3662 8575-8578 Protein denotes MPO
T3663 8607-8618 Protein_catabolism denotes degradation
T4230 9821-9830 Protein denotes EPICS XL2
T4558 10159-10174 Protein denotes Surface Antigen
T4559 10175-10185 Gene_expression denotes Expression
T4561 10453-10460 Binding denotes binding
T4560 10464-10476 Protein denotes Fc receptors
T4562 10644-10647 Protein denotes IgG
T4563 10764-10773 Protein denotes EPICS XL2
T4729 10963-10975 Protein denotes TNF Activity
T4730 11160-11167 Protein denotes TNF-α/β
T4731 11264-11267 Protein denotes TNF
T4732 11287-11296 Gene_expression denotes expressed
T5213 11475-11502 Protein denotes M-MLV reverse transcriptase
T5214 11757-11780 Protein denotes Goldstar DNA polymerase
T5215 11815-11838 Protein denotes Goldstar DNA polymerase
T5216 12041-12048 Protein denotes β-actin
T5217 12176-12181 Protein denotes TNF-α
T5218 12312-12318 Protein denotes ICAM-1
T5454 12632-12637 Protein denotes NF-κB
T5455 12666-12683 Protein denotes MHC class I locus
T5456 12708-12723 Protein denotes luciferase gene
T5457 12899-12909 Protein denotes Luciferase
T6441 13447-13450 Protein denotes Rad
T6442 13595-13608 Protein denotes I-κBα protein
T6443 13702-13724 Protein denotes horseradish peroxidase
T6444 13808-13811 Protein denotes IκB
T6445 13969-13978 Protein denotes α-Tubulin
T6446 14024-14037 Protein denotes nuclear NF-κB
T6447 14652-14683 Protein denotes Rabbit polyclonal antibody anti
T6448 14684-14689 Protein denotes NF-κB
T6449 14690-14701 Protein denotes p50 subunit
T6450 14716-14738 Protein denotes anti-NF-κB p65 subunit
T6451 14912-14955 Protein denotes HRP-conjugated F(ab')2 goat anti-rabbit IgG
T6452 15364-15367 Protein denotes ERK
T6512 15400-15405 Protein denotes NF-κB
T6513 15406-15416 Positive_regulation denotes Activation
T6515 15435-15442 Entity denotes Nuclear
T6516 15443-15453 Positive_regulation denotes activation
T6514 15457-15462 Protein denotes NF−κΒ
T7125 16230-16245 Protein denotes myeloperoxidase
T15793 17414-17429 Protein denotes Myeloperoxidase
T15794 17431-17434 Protein denotes MPO
T8187 17738-17748 Gene_expression denotes Production
T8188 17806-17810 Protein denotes dCGN
T8191 17814-17823 Positive_regulation denotes stimulate
T8189 17824-17829 Protein denotes TNF-α
T8190 17830-17840 Gene_expression denotes production
T8192 17946-17951 Protein denotes TNF-α
T8193 17957-17964 Positive_regulation denotes induced
T8196 18087-18095 Positive_regulation denotes increase
T8194 18099-18104 Protein denotes TNF-α
T8195 18105-18115 Gene_expression denotes production
T8199 18262-18270 Positive_regulation denotes increase
T8197 18274-18279 Protein denotes TNF-α
T8198 18280-18290 Gene_expression denotes production
T8200 18338-18343 Protein denotes TNF-α
T8201 18344-18354 Gene_expression denotes production
T8202 18355-18364 Positive_regulation denotes increased
T8205 18459-18467 Localization denotes secreted
T8203 18468-18473 Protein denotes TNF-α
T8204 18507-18512 Protein denotes TNF-α
T8208 18579-18586 Positive_regulation denotes induced
T8206 18587-18592 Protein denotes TNF-α
T8207 18593-18603 Gene_expression denotes production
T8209 18668-18673 Protein denotes TNF-α
T8210 18674-18682 Gene_expression denotes produced
T8213 18900-18908 Positive_regulation denotes increase
T8211 18912-18917 Protein denotes TNF-α
T8212 18918-18928 Gene_expression denotes production
T8216 18945-18953 Positive_regulation denotes increase
T8214 18957-18962 Protein denotes TNF-α
T8215 18963-18973 Gene_expression denotes production
T8217 19060-19065 Protein denotes TNF-α
T8218 19070-19078 Localization denotes released
T8219 19131-19136 Protein denotes TNF-α
T8220 19137-19147 Gene_expression denotes production
T8221 19176-19185 Positive_regulation denotes dependent
T8222 19315-19320 Protein denotes TNF-α
T8223 19321-19328 Localization denotes release
T16326 19527-19537 Positive_regulation denotes stimulated
T16324 19538-19541 Protein denotes TNF
T16325 19542-19551 Localization denotes secretion
T16327 19578-19581 Protein denotes TNF
T16328 19582-19590 Localization denotes released
T16329 19683-19686 Protein denotes TNF
T16330 19687-19694 Localization denotes release
T16331 19695-19702 Positive_regulation denotes induced
T16332 19799-19802 Protein denotes TNF
T16333 19803-19810 Localization denotes release
T16334 19811-19818 Positive_regulation denotes induced
T16335 19972-19975 Protein denotes TNF
T16336 19976-19983 Localization denotes release
T16337 19984-19991 Positive_regulation denotes induced
T16338 20155-20158 Protein denotes TNF
T16339 20159-20166 Localization denotes release
T16340 20167-20174 Positive_regulation denotes induced
T8668 20924-20932 Protein denotes C10 dCGN
T16607 21369-21376 Positive_regulation denotes induced
T16606 21377-21381 Protein denotes THP1
T9552 22318-22328 Positive_regulation denotes stimulated
T9553 22318-22328 Positive_regulation denotes stimulated
T9550 22329-22339 Gene_expression denotes expression
T9551 22329-22339 Gene_expression denotes expression
T9548 22343-22349 Protein denotes ICAM-1
T9549 22351-22355 Protein denotes CD54
T9556 22395-22403 Positive_regulation denotes increase
T9554 22407-22413 Protein denotes ICAM-1
T9555 22414-22424 Gene_expression denotes expression
T9557 22516-22556 Protein denotes lymphocyte function-associated antigen 3
T9558 22558-22562 Protein denotes CD58
T9559 22577-22584 Negative_regulation denotes reduced
T9560 22577-22584 Negative_regulation denotes reduced
T9563 22651-22661 Gene_expression denotes expression
T9564 22651-22661 Gene_expression denotes expression
T9561 22665-22707 Protein denotes major histocompatibility complex molecules
T9562 22786-22790 Protein denotes CD14
T9565 22805-22812 Negative_regulation denotes reduced
T9566 22805-22812 Negative_regulation denotes reduced
T16968 23180-23187 Protein denotes Antigen
T16969 23188-23198 Gene_expression denotes expression
T16970 23253-23259 Protein denotes ICAM-1
T16971 23260-23270 Gene_expression denotes expression
T16977 23387-23397 Gene_expression denotes expression
T16978 23387-23397 Gene_expression denotes expression
T16979 23387-23397 Gene_expression denotes expression
T16980 23387-23397 Gene_expression denotes expression
T16981 23387-23397 Gene_expression denotes expression
T16972 23414-23421 Protein denotes HLA-ABC
T16973 23423-23429 Protein denotes HLA-DR
T16974 23431-23435 Protein denotes CD14
T16975 23437-23443 Protein denotes ICAM-1
T16976 23449-23453 Protein denotes CD58
T9567 23884-23890 Protein denotes ICAM-1
T9568 24068-24088 Protein denotes anti-ICAM-1 antibody
T9569 24098-24102 Protein denotes CD58
T9570 24135-24139 Protein denotes IgG1
T9571 24154-24174 Protein denotes anti-ICAM-1 antibody
T9572 24278-24284 Protein denotes ICAM-1
T9575 24335-24342 Regulation denotes control
T9576 24335-24342 Regulation denotes control
T9573 24343-24347 Protein denotes IgG1
T9574 24356-24374 Protein denotes anti-CD58 antibody
T9857 25115-25123 Positive_regulation denotes Increase
T9858 25115-25123 Positive_regulation denotes Increase
T9853 25127-25133 Protein denotes ICAM-1
T9854 25138-25148 Protein denotes TNF-α mRNA
T9855 25149-25159 Gene_expression denotes Expression
T9856 25149-25159 Gene_expression denotes Expression
T9863 25164-25172 Positive_regulation denotes increase
T9864 25164-25172 Positive_regulation denotes increase
T9859 25176-25190 Protein denotes surface ICAM-1
T9861 25191-25201 Gene_expression denotes expression
T9860 25206-25211 Protein denotes TNF-α
T9862 25212-25222 Gene_expression denotes production
T9869 25342-25350 Positive_regulation denotes increase
T9870 25342-25350 Positive_regulation denotes increase
T9865 25368-25374 Protein denotes ICAM-1
T9866 25379-25384 Protein denotes TNF-α
T9867 25386-25389 Protein denotes Fig
T9868 25395-25407 Protein denotes β-actin mRNA
T9871 25424-25432 Regulation denotes affected
T17457 25496-25504 Protein_catabolism denotes Degraded
T17454 25505-25508 Protein denotes CGN
T17460 25509-25519 Positive_regulation denotes stimulated
T17461 25509-25519 Positive_regulation denotes stimulated
T17455 25520-25526 Protein denotes ICAM-1
T17456 25531-25536 Protein denotes TNF-α
T17458 25542-25552 Gene_expression denotes expression
T17459 25542-25552 Gene_expression denotes expression
T17466 25622-25632 Gene_expression denotes expression
T17467 25622-25632 Gene_expression denotes expression
T17462 25636-25642 Protein denotes ICAM-1
T17463 25647-25652 Protein denotes TNF-α
T17464 25707-25710 Protein denotes CGN
T17465 25712-25719 Protein denotes β-actin
T17468 25720-25730 Gene_expression denotes expression
T17469 25720-25730 Gene_expression denotes expression
T11070 25764-25799 Protein denotes Degraded CGN Induce IκB Degradation
T11071 25804-25809 Protein denotes NF-κB
T11072 25810-25820 Positive_regulation denotes Activation
T11073 25810-25820 Positive_regulation denotes Activation
T11077 25825-25835 Gene_expression denotes expression
T11078 25825-25835 Gene_expression denotes expression
T11074 25858-25864 Protein denotes ICAM-1
T11075 25869-25874 Protein denotes TNF-α
T11079 25878-25888 Regulation denotes controlled
T11080 25878-25888 Regulation denotes controlled
T11076 25896-25916 Protein denotes nuclear factor NF-κB
T11083 25932-25947 Phosphorylation denotes phosphorylation
T11081 25965-25968 Protein denotes IκB
T11084 26031-26041 Positive_regulation denotes activation
T11082 26049-26054 Protein denotes NF-κB
T11085 26093-26098 Protein denotes NF-κB
T11090 26138-26145 Positive_regulation denotes induced
T11088 26155-26165 Positive_regulation denotes activation
T11086 26169-26174 Protein denotes NF-κB
T11089 26195-26203 Positive_regulation denotes increase
T11087 26207-26217 Protein denotes luciferase
T11093 26262-26269 Positive_regulation denotes induced
T11091 26270-26275 Protein denotes NF-κB
T11092 26276-26286 Positive_regulation denotes activation
T11095 26440-26449 Gene_expression denotes detecting
T11094 26450-26455 Protein denotes NF-κB
T11096 26576-26590 Protein denotes NF-κB subunits
T11097 26596-26605 Positive_regulation denotes activated
T11102 26649-26656 Positive_regulation denotes induced
T11101 26657-26667 Positive_regulation denotes activation
T11098 26675-26678 Protein denotes p50
T11099 26683-26695 Protein denotes p65 subunits
T11100 26699-26704 Protein denotes NF-κB
T11106 26878-26885 Positive_regulation denotes induced
T11105 26897-26907 Positive_regulation denotes activation
T11103 26911-26916 Protein denotes NF-κB
T11104 26918-26925 Protein denotes Fig. 7C
T11107 27193-27206 Protein denotes nuclear NF-κB
T11108 27208-27215 Protein denotes Fig. 7D
T11113 27259-27266 Positive_regulation denotes induced
T11112 27270-27278 Positive_regulation denotes increase
T11109 27286-27289 Protein denotes p50
T11110 27294-27306 Protein denotes p65 subunits
T11111 27310-27315 Protein denotes NF-κB
T11116 27387-27395 Positive_regulation denotes increase
T11117 27387-27395 Positive_regulation denotes increase
T11114 27399-27404 Protein denotes NF-κB
T11115 27406-27413 Protein denotes Fig. 7D
T11118 27465-27468 Protein denotes p50
T11119 27469-27472 Protein denotes p65
T11120 27480-27493 Protein denotes NF-κB isoform
T11121 27494-27503 Positive_regulation denotes activated
T11122 27494-27503 Positive_regulation denotes activated
T11124 27547-27558 Protein_catabolism denotes degradation
T11123 27566-27580 Protein denotes inhibitor IκBα
T11125 27652-27656 Protein denotes IκBα
T11127 27657-27668 Protein_catabolism denotes degradation
T11126 27722-27726 Protein denotes IκBα
T11128 27740-27748 Protein_catabolism denotes degraded
T11129 27806-27818 Protein denotes IκBα subunit
T11130 27872-27875 Protein denotes p65
T11131 27900-27908 Protein_catabolism denotes degraded
T18202 27987-27995 Protein_catabolism denotes Degraded
T18200 27996-27999 Protein denotes CGN
T18203 28000-28009 Positive_regulation denotes activated
T18204 28000-28009 Positive_regulation denotes activated
T18201 28014-28019 Protein denotes NF-kB
T18205 28081-28095 Protein denotes NF-κB reporter
T18207 28112-28122 Gene_expression denotes expression
T18206 28126-28136 Protein denotes luciferase
T18208 28457-28474 Protein denotes IκBα or α−tubulin
T18211 28527-28534 Positive_regulation denotes induced
T18210 28535-28545 Positive_regulation denotes activation
T18209 28549-28554 Protein denotes NF-κB
T18212 28820-28825 Protein denotes NF-κB
T18213 28826-28837 Protein denotes p50 subunit
T18214 28839-28842 Protein denotes p50
T18215 28847-28852 Protein denotes NF-κB
T18216 28853-28864 Protein denotes p65 subunit
T18217 28866-28869 Protein denotes p65
T18218 28915-28918 Protein denotes ERK
T18221 29060-29067 Positive_regulation denotes induced
T18220 29068-29078 Positive_regulation denotes activation
T18219 29082-29087 Protein denotes NF-κB
T18222 29152-29157 Protein denotes NF-κB
T18223 29158-29169 Protein denotes p50 subunit
T18224 29173-29178 Protein denotes NF-κB
T18225 29179-29182 Protein denotes p65
T15436 30771-30779 Protein_catabolism denotes degraded
T15435 30780-30783 Protein denotes CGN
T15437 32372-32375 Protein denotes MPO
T15439 32550-32560 Gene_expression denotes production
T15438 32564-32567 Protein denotes TNF
T15442 32630-32637 Positive_regulation denotes induced
T15441 32647-32657 Gene_expression denotes production
T15440 32661-32664 Protein denotes TNF
T15444 32825-32832 Gene_expression denotes produce
T15443 32833-32836 Protein denotes TNF
T15446 33035-33043 Protein_catabolism denotes degraded
T15445 33053-33056 Protein denotes CGN
T15447 33104-33107 Protein denotes TNF
T15448 33108-33116 Localization denotes secreted
T15449 33124-33131 Positive_regulation denotes induced
T15450 33170-33178 Localization denotes secreted
T15451 33271-33275 Protein denotes CD14
T15452 33280-33294 Protein denotes TLR4 receptors
T15453 33422-33426 Protein denotes CD14
T15454 33434-33443 Gene_expression denotes expressed
T15457 33628-33635 Positive_regulation denotes induced
T15455 33636-33639 Protein denotes TNF
T15456 33640-33649 Localization denotes secretion
T15458 33663-33666 Protein denotes TNF
T15459 33851-33854 Protein denotes TNF
T15460 33855-33863 Localization denotes secreted
T15461 33924-33931 Positive_regulation denotes induced
T15462 33999-34002 Protein denotes TNF
T15463 34003-34012 Localization denotes secretion
T15464 34169-34173 Protein denotes CD14
T15467 34196-34205 Negative_regulation denotes inhibited
T15465 34219-34222 Protein denotes TNF
T15466 34223-34232 Localization denotes secretion
T15468 34246-34250 Protein denotes TLR4
T15469 34315-34318 Protein denotes CGN
T15470 34385-34389 Protein denotes TLR4
T15472 34393-34402 Positive_regulation denotes activated
T15471 34430-34439 Localization denotes secretion
T15473 34481-34485 Protein denotes TLR4
T15475 34704-34714 Gene_expression denotes expression
T15474 34740-34746 Protein denotes ICAM-1
T15476 34751-34759 Positive_regulation denotes enhanced
T15478 34798-34808 Gene_expression denotes expression
T15477 34812-34818 Protein denotes ICAM-1
T15480 34972-34982 Gene_expression denotes expression
T15479 34986-34992 Protein denotes ICAM-1
T15481 34993-35000 Positive_regulation denotes induced
T15485 35363-35372 Positive_regulation denotes increased
T15489 35363-35372 Positive_regulation denotes increased
T15490 35363-35372 Positive_regulation denotes increased
T15491 35363-35372 Positive_regulation denotes increased
T15486 35373-35383 Gene_expression denotes expression
T15487 35373-35383 Gene_expression denotes expression
T15488 35373-35383 Gene_expression denotes expression
T15482 35394-35400 Protein denotes ICAM-1
T15483 35405-35410 Protein denotes LFA-3
T15484 35412-35416 Protein denotes CD58
T15493 35503-35511 Protein_catabolism denotes degraded
T15492 35512-35515 Protein denotes CGN
T15494 35765-35770 Protein denotes NF-κB
T15499 35795-35806 Regulation denotes responsible
T15500 35795-35806 Regulation denotes responsible
T15495 35811-35817 Protein denotes ICAM-1
T15496 35822-35827 Protein denotes TNF-α
T15497 35828-35838 Gene_expression denotes expression
T15498 35828-35838 Gene_expression denotes expression
T15501 35840-35845 Protein denotes NF-κB
T15503 35846-35856 Positive_regulation denotes activation
T15505 35846-35856 Positive_regulation denotes activation
T15504 35880-35891 Protein_catabolism denotes degradation
T15502 35899-35920 Protein denotes inhibitor protein IκB
T15517 35940-35947 Positive_regulation denotes induced
T15506 35948-35953 Protein denotes NF-κB
T15513 35954-35964 Positive_regulation denotes activation
T15514 35977-35988 Protein_catabolism denotes degradation
T15507 35992-35996 Protein denotes IκBα
T15518 35998-36011 Localization denotes translocation
T15519 35998-36011 Localization denotes translocation
T15520 35998-36011 Localization denotes translocation
T15508 36015-36018 Protein denotes p65
T15509 36023-36026 Protein denotes p50
T15515 36044-36051 Entity denotes nucleus
T15516 36059-36069 Positive_regulation denotes activation
T15521 36059-36069 Positive_regulation denotes activation
T15522 36059-36069 Positive_regulation denotes activation
T15523 36059-36069 Positive_regulation denotes activation
T15510 36076-36078 Protein denotes NF
T15511 36079-36081 Protein denotes κB
T15512 36093-36103 Protein denotes luciferase
T15525 36140-36150 Positive_regulation denotes activation
T15524 36154-36159 Protein denotes NF-κB
T15526 36164-36171 Positive_regulation denotes induced
T15529 36365-36372 Positive_regulation denotes induced
T15528 36373-36383 Positive_regulation denotes activation
T15527 36387-36392 Protein denotes NF-κB
T15530 36433-36438 Protein denotes NF-κB
T15531 36649-36654 Protein denotes NF-kB
T15532 36779-36784 Protein denotes NF-κB
T15534 36785-36795 Positive_regulation denotes activation
T15535 36796-36806 Negative_regulation denotes suppressed
T15533 36807-36811 Protein denotes cdk4
T15536 36812-36822 Gene_expression denotes expression
T15537 36833-36842 Positive_regulation denotes necessary
T15538 36883-36888 Protein denotes NF-κB
T15541 36889-36899 Positive_regulation denotes activation
T15539 36996-36999 Protein denotes cdk
T15540 37010-37013 Protein denotes p21
T15542 37043-37046 Protein denotes p21
T15543 37051-37055 Protein denotes cdk4
T15544 37056-37066 Gene_expression denotes expression
T15545 37056-37066 Gene_expression denotes expression
T15549 37248-37258 Gene_expression denotes expression
T15546 37284-37290 Protein denotes ICAM-1
T15547 37295-37300 Protein denotes TNF-α
T15550 37301-37311 Gene_expression denotes production
T15551 37301-37311 Gene_expression denotes production
T15548 37321-37326 Protein denotes NF-κB
T15553 37348-37358 Gene_expression denotes expression
T15552 37362-37368 Protein denotes ICAM-1
T15559 38200-38209 Positive_regulation denotes increased
T15554 38210-38216 Protein denotes ICAM-1
T15557 38217-38227 Gene_expression denotes expression
T15555 38240-38246 Protein denotes ICAM-1
T15560 38292-38302 Positive_regulation denotes stimulated
T15556 38303-38308 Protein denotes TNF-α
T15558 38309-38319 Gene_expression denotes expression
T15561 38418-38423 Protein denotes NF-κB
T15562 38424-38434 Positive_regulation denotes activation
R13259 T15435 T15436 themeOf CGN,degraded
R13261 T15438 T15439 themeOf TNF,production
R13265 T15440 T15441 themeOf TNF,production
R13268 T15441 T15442 themeOf production,induced
R13271 T15443 T15444 themeOf TNF,produce
R13275 T15445 T15446 themeOf CGN,degraded
R13278 T15447 T15448 themeOf TNF,secreted
R13279 T15447 T15450 themeOf TNF,secreted
R13282 T15448 T15449 themeOf secreted,induced
R13283 T15453 T15454 themeOf CD14,expressed
R13288 T15455 T15456 themeOf TNF,secretion
R13289 T15456 T15457 themeOf secretion,induced
R13290 T15459 T15460 themeOf TNF,secreted
R13291 T15460 T15461 themeOf secreted,induced
R13292 T15462 T15463 themeOf TNF,secretion
R13293 T15465 T15466 themeOf TNF,secretion
R13294 T15492 T15493 themeOf CGN,degraded
R13295 T15466 T15467 themeOf secretion,inhibited
R13296 T15495 T15497 themeOf ICAM-1,expression
R13297 T15470 T15471 themeOf TLR4,secretion
R13298 T15496 T15498 themeOf TNF-α,expression
R13299 T15497 T15499 themeOf expression,responsible
R13300 T15498 T15500 themeOf expression,responsible
R13301 T15501 T15503 themeOf NF-κB,activation
R13302 T15502 T15504 themeOf inhibitor protein IκB,degradation
R13303 T15471 T15472 themeOf secretion,activated
R13304 T15504 T15505 themeOf degradation,activation
R13305 T15474 T15475 themeOf ICAM-1,expression
R13306 T15506 T15513 themeOf NF-κB,activation
R13307 T15507 T15514 themeOf IκBα,degradation
R13308 T15507 T15518 themeOf IκBα,translocation
R13309 T15508 T15519 themeOf p65,translocation
R13310 T15509 T15520 themeOf p50,translocation
R13311 T15475 T15476 themeOf expression,enhanced
R13312 T15512 T15516 themeOf luciferase,activation
R13313 T15513 T15517 themeOf activation,induced
R13314 T15477 T15478 themeOf ICAM-1,expression
R13315 T15515 T15518 locationOf nucleus,translocation
R13316 T15515 T15519 locationOf nucleus,translocation
R13317 T15515 T15520 locationOf nucleus,translocation
R13318 T15518 T15521 themeOf translocation,activation
R13319 T15479 T15480 themeOf ICAM-1,expression
R13320 T15519 T15522 themeOf translocation,activation
R13321 T15520 T15523 themeOf translocation,activation
R13322 T15480 T15481 themeOf expression,induced
R13323 T15524 T15525 themeOf NF-κB,activation
R13324 T15482 T15485 themeOf ICAM-1,increased
R13325 T15525 T15526 themeOf activation,induced
R13326 T15527 T15528 themeOf NF-κB,activation
R13327 T15528 T15529 themeOf activation,induced
R13328 T15482 T15486 themeOf ICAM-1,expression
R13329 T15483 T15487 themeOf LFA-3,expression
R13330 T15532 T15534 themeOf NF-κB,activation
R13331 T15533 T15536 themeOf cdk4,expression
R13332 T15534 T15535 themeOf activation,suppressed
R13333 T15484 T15488 themeOf CD58,expression
R13334 T15536 T15537 themeOf expression,necessary
R13335 T15486 T15489 themeOf expression,increased
R13336 T15538 T15541 themeOf NF-κB,activation
R13337 T15487 T15490 themeOf expression,increased
R13338 T15542 T15544 themeOf p21,expression
R13339 T15543 T15545 themeOf cdk4,expression
R13340 T15488 T15491 themeOf expression,increased
R13341 T15546 T15549 themeOf ICAM-1,expression
R13342 T15546 T15550 themeOf ICAM-1,production
R13343 T15547 T15551 themeOf TNF-α,production
R13344 T15552 T15553 themeOf ICAM-1,expression
R13345 T15554 T15557 themeOf ICAM-1,expression
R13346 T15556 T15558 themeOf TNF-α,expression
R13347 T15557 T15559 themeOf expression,increased
R13348 T15558 T15560 themeOf expression,stimulated
R13349 T15561 T15562 themeOf NF-κB,activation
R14003 T16324 T16325 themeOf TNF,secretion
R14004 T16325 T16326 themeOf secretion,stimulated
R14005 T16327 T16328 themeOf TNF,released
R14006 T16329 T16330 themeOf TNF,release
R14007 T16330 T16331 themeOf release,induced
R14008 T16332 T16333 themeOf TNF,release
R14009 T16333 T16334 themeOf release,induced
R14010 T16335 T16336 themeOf TNF,release
R14011 T16336 T16337 themeOf release,induced
R14012 T16338 T16339 themeOf TNF,release
R14013 T16339 T16340 themeOf release,induced
R14249 T16606 T16607 themeOf THP1,induced
R14537 T16968 T16969 themeOf Antigen,expression
R14538 T16970 T16971 themeOf ICAM-1,expression
R14539 T16972 T16977 themeOf HLA-ABC,expression
R14540 T16973 T16978 themeOf HLA-DR,expression
R14541 T16974 T16979 themeOf CD14,expression
R14542 T16975 T16980 themeOf ICAM-1,expression
R14543 T16976 T16981 themeOf CD58,expression
R14929 T17454 T17457 themeOf CGN,Degraded
R14930 T17455 T17458 themeOf ICAM-1,expression
R14931 T17456 T17459 themeOf TNF-α,expression
R14932 T17457 T17460 causeOf Degraded,stimulated
R14933 T17457 T17461 causeOf Degraded,stimulated
R14934 T17458 T17460 themeOf expression,stimulated
R14935 T17459 T17461 themeOf expression,stimulated
R14936 T17462 T17466 themeOf ICAM-1,expression
R14937 T17463 T17467 themeOf TNF-α,expression
R14938 T17464 T17468 themeOf CGN,expression
R14939 T17465 T17469 themeOf β-actin,expression
R15552 T18200 T18202 themeOf CGN,Degraded
R15553 T18200 T18203 causeOf CGN,activated
R15554 T18200 T18204 causeOf CGN,activated
R15555 T18201 T18203 themeOf NF-kB,activated
R15556 T18202 T18204 themeOf Degraded,activated
R15557 T18206 T18207 themeOf luciferase,expression
R15558 T18209 T18210 themeOf NF-κB,activation
R15559 T18210 T18211 themeOf activation,induced
R15560 T18219 T18220 themeOf NF-κB,activation
R15561 T18220 T18221 themeOf activation,induced
R1767 T2034 T2036 themeOf Nuclear Factor-κB,activation
R1768 T2035 T2037 themeOf NF-κB,activation
R1769 T2038 T2039 themeOf NF-κB,regulates
R1770 T2040 T2043 themeOf ICAM-1,expression
R1771 T2042 T2044 themeOf TNF-α,expression
R1772 T2043 T2045 themeOf expression,increased
R1773 T2044 T2046 themeOf expression,stimulated
R1774 T2047 T2048 themeOf NF-κB,activation
R1775 T2049 T2050 themeOf CGN,degraded
R3271 T3656 T3658 themeOf myeloperoxidase,collected
R3272 T3657 T3659 themeOf MPO,collected
R3273 T3660 T3661 themeOf MPO,expressed
R3274 T3662 T3663 themeOf MPO,degradation
R4090 T4558 T4559 themeOf Surface Antigen,Expression
R4091 T4560 T4561 themeOf Fc receptors,binding
R4212 T4731 T4732 themeOf TNF,expressed
R536 T662 T664 themeOf TNF,Secretion
R537 T663 T666 themeOf NF-κB,Activation
R538 T664 T665 themeOf Secretion,Upregulation
R539 T664 T667 themeOf Secretion,Induces
R540 T665 T668 themeOf Upregulation,Induces
R541 T666 T667 causeOf Activation,Induces
R542 T666 T668 causeOf Activation,Induces
R543 T671 T672 themeOf expression,increased
R544 T675 T678 causeOf dCGN,stimulated
R545 T676 T677 themeOf TNF-α,expression
R546 T677 T678 themeOf expression,stimulated
R547 T679 T680 themeOf NF-κB,activation
R548 T681 T682 themeOf CGN,degraded
R555 T670 T671 themeOf ICAM-1,expression
R5797 T6512 T6513 themeOf NF-κB,Activation
R5798 T6514 T6516 themeOf NF−κΒ,activation
R5799 T6515 T6516 Site Nuclear,activation
R7214 T8185 T8186 themeOf "CGN 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-TNF-α",Degraded
R7215 T8185 T8187 themeOf "CGN 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-TNF-α",Production
R7216 T8188 T8191 causeOf dCGN,stimulate
R7217 T8189 T8190 themeOf TNF-α,production
R7218 T8190 T8191 themeOf production,stimulate
R7219 T8192 T8193 themeOf TNF-α,induced
R7220 T8194 T8195 themeOf TNF-α,production
R7221 T8195 T8196 themeOf production,increase
R7222 T8197 T8198 themeOf TNF-α,production
R7223 T8198 T8199 themeOf production,increase
R7224 T8200 T8201 themeOf TNF-α,production
R7225 T8201 T8202 themeOf production,increased
R7226 T8203 T8205 themeOf TNF-α,secreted
R7227 T8206 T8207 themeOf TNF-α,production
R7228 T8207 T8208 themeOf production,induced
R7229 T8209 T8210 themeOf TNF-α,produced
R7230 T8211 T8212 themeOf TNF-α,production
R7231 T8212 T8213 themeOf production,increase
R7232 T8214 T8215 themeOf TNF-α,production
R7233 T8215 T8216 themeOf production,increase
R7234 T8217 T8218 themeOf TNF-α,released
R7235 T8219 T8220 themeOf TNF-α,production
R7236 T8220 T8221 themeOf production,dependent
R7237 T8222 T8223 themeOf TNF-α,release
R8398 T9548 T9550 themeOf ICAM-1,expression
R8399 T9549 T9551 themeOf CD54,expression
R8400 T9550 T9552 themeOf expression,stimulated
R8401 T9551 T9553 themeOf expression,stimulated
R8402 T9554 T9555 themeOf ICAM-1,expression
R8403 T9555 T9556 themeOf expression,increase
R8404 T9557 T9559 themeOf lymphocyte function-associated antigen 3,reduced
R8405 T9558 T9560 themeOf CD58,reduced
R8406 T9561 T9563 themeOf major histocompatibility complex molecules,expression
R8407 T9562 T9564 themeOf CD14,expression
R8408 T9563 T9565 themeOf expression,reduced
R8409 T9564 T9566 themeOf expression,reduced
R8410 T9573 T9575 themeOf IgG1,control
R8411 T9574 T9576 themeOf anti-CD58 antibody,control
R8625 T9853 T9855 themeOf ICAM-1,Expression
R8626 T9854 T9856 themeOf TNF-α mRNA,Expression
R8627 T9855 T9857 themeOf Expression,Increase
R8628 T9856 T9858 themeOf Expression,Increase
R8629 T9859 T9861 themeOf surface ICAM-1,expression
R8630 T9860 T9862 themeOf TNF-α,production
R8631 T9861 T9863 themeOf expression,increase
R8632 T9862 T9864 themeOf production,increase
R8633 T9865 T9869 themeOf ICAM-1,increase
R8634 T9866 T9870 themeOf TNF-α,increase
R8635 T9868 T9871 themeOf β-actin mRNA,affected
R9562 T11070 T11072 themeOf Degraded CGN Induce IκB Degradation,Activation
R9563 T11071 T11073 themeOf NF-κB,Activation
R9564 T11074 T11077 themeOf ICAM-1,expression
R9565 T11075 T11078 themeOf TNF-α,expression
R9566 T11076 T11079 causeOf nuclear factor NF-κB,controlled
R9567 T11076 T11080 causeOf nuclear factor NF-κB,controlled
R9568 T11077 T11079 themeOf expression,controlled
R9569 T11078 T11080 themeOf expression,controlled
R9570 T11081 T11083 themeOf IκB,phosphorylation
R9571 T11082 T11084 themeOf NF-κB,activation
R9572 T11086 T11088 themeOf NF-κB,activation
R9573 T11087 T11089 themeOf luciferase,increase
R9574 T11088 T11090 themeOf activation,induced
R9575 T11091 T11092 themeOf NF-κB,activation
R9576 T11092 T11093 themeOf activation,induced
R9577 T11094 T11095 themeOf NF-κB,detecting
R9578 T11096 T11097 themeOf NF-κB subunits,activated
R9579 T11098 T11101 themeOf p50,activation
R9580 T11101 T11102 themeOf activation,induced
R9581 T11103 T11105 themeOf NF-κB,activation
R9582 T11104 T11106 causeOf Fig. 7C,induced
R9583 T11105 T11106 themeOf activation,induced
R9584 T11109 T11112 themeOf p50,increase
R9585 T11112 T11113 themeOf increase,induced
R9586 T11114 T11116 themeOf NF-κB,increase
R9587 T11115 T11117 themeOf Fig. 7D,increase
R9588 T11118 T11121 themeOf p50,activated
R9589 T11120 T11122 themeOf NF-κB isoform,activated
R9590 T11123 T11124 themeOf inhibitor IκBα,degradation
R9591 T11125 T11127 themeOf IκBα,degradation
R9592 T11126 T11128 themeOf IκBα,degraded
R9593 T11130 T11131 themeOf p65,degraded