PMC:2800179 / 29490-38613 JSON TXT

Annnotations TAB JSON ListView MergeView

ICD10

{"project":"ICD10","denotations":[{"id":"T15083","span":{"begin":5737,"end":5752},"obj":"http://purl.bioontology.org/ontology/ICD10/K50.9"},{"id":"T15084","span":{"begin":5979,"end":5994},"obj":"http://purl.bioontology.org/ontology/ICD10/K50.9"},{"id":"T15085","span":{"begin":6187,"end":6202},"obj":"http://purl.bioontology.org/ontology/ICD10/K50.9"},{"id":"T15086","span":{"begin":7963,"end":7978},"obj":"http://purl.bioontology.org/ontology/ICD10/K50.9"},{"id":"T15087","span":{"begin":5838,"end":5856},"obj":"http://purl.bioontology.org/ontology/ICD10/K51"},{"id":"T15088","span":{"begin":5838,"end":5856},"obj":"http://purl.bioontology.org/ontology/ICD10/K51.9"}],"text":"Discussion\nInflammation of the intestinal tract is usually associated with infiltration and activation of intestinal macrophages [17]. These macrophages are able to initiate immune responses and can be induced to differentiate into cells that either exacerbate or inhibit the inflammation. Accumulation of different types of leukocytes, including monocytes/macrophages, neutrophils, and lymphocytes in the intestinal mucosa during inflammation, is normally followed by secretion of pro-inflammatory cytokines [33]. Several stimuli can induce these leukocytes to produce and secrete cytokines during inflammation. One of the most potent and known stimuli for leukocyte activation is LPS from Gram-negative bacteria [34]. In addition, other factors are also able to stimulate cytokine secretion from various leukocytes [35], [36]. One such factor is CGN, a high molecular weight sulphated polysaccharide (\u003e200 kDa) derived from red algae (Rhodophyceae) [1], [2]. Native CGN is widely used as a food additive (E 407) to improve texture. It is also used in cosmetics and pharmaceuticals. Although native form CGN (200–800 kDa) has been declared harmless to humans [8], its degraded forms (\u003c50 kDa), also known as poligeenan, are widely used to induce colitis in rodents [3]–[5]. These degraded CGN may also have a possible carcinogenic effect [4], [6]–[8]; however this is still controversial.\nAlthough acid treatment at high temperature (80°C) is required for CGN hydrolysis in vitro to lower molecular weight dCGN, it is probable that some dCGN are produced by acid hydrolysis during gastric digestion [9], [10] or interaction with intestinal bacteria [11], [12]. Thus, understanding the mechanisms of dCGN-induced bowel inflammation is of great importance. In this report, we have analyzed the role of human monocytes (PBM and THP-1) in dCGN-induced inflammation.\nPreliminary in vivo studies in rats treated with dCGN revealed significant shortening of the large intestine associated with an inflammatory state, i.e. strong infiltration of macrophages to the intestinal mucosa similar to DSS-induced inflammation [20]. Using two fractions of dCGN (10 and 40 kDa), we observed a strong correlation between the severity of the inflammation and the dCGN molecular size, thus confirming the size related inflammation in vivo. This macrophage accumulation was not due to cell proliferation because dCGN inhibited THP-1 monocytes proliferation in vitro. These results are similar to those obtained with human colonic epithelial cells (NCM460 cell line) exposed to native CGN for 1–8 days [37]. Thus, it seems that dCGN promote macrophage infiltration by recruiting new cells to the inflamed intestinal mucosa and not by inducing cell proliferation. In addition, very few polymorphonuclear cells were detected in the mucosa at the time point analyzed as demonstrated by a very low level of MPO in the intestinal tissue.\nThese results suggest that monocytes might produce cytokines associated with activation into macrophages in response to dCGN. Thus, we analyzed the production of TNF by both PBM and THP-1 cells in response to dCGN. Degraded CGN induced a robust production of TNF by monocytes. The 40 kDa form of dCGN was more potent for monocyte stimulation than the 10 kDa or the native ones. Surprisingly, monocyte activation by dCGN to produce TNF was much stronger than the activation induced by LPS, an inflammatory factor considered to be among the most potent stimuli for leukocyte activation. These results underline the fact that partially degraded forms of CGN have important cellular effects. The amount of TNF secreted by PBM induced with LPS was much larger than the one secreted by THP-1 monocytes. Since monocyte activation by LPS is associated with the presence of the CD14 and TLR4 receptors [38]–[40], the different response observed could be due to the different expression of these receptors in PBM and THP-1 cells. CD14 is not expressed by THP-1 monocytes, but it is expressed by PBM. This fact could explain why THP-1 cells produced a much smaller response to LPS than PBM and also the difference of kinetics in the LPS induced TNF secretion. The peak of TNF response was observed after 8 h stimulation followed by a rapid decrease to baseline at 10 h, whereas on THP-1 cells the peak was not reached until after 56 h. Moreover, the amount of TNF secreted by monocytes induced with dCGN was much larger than the one induced by LPS. On the other hand, LPS and dCGN displayed a very different TNF secretion curve in THP-1 cells. These differences suggest that dCGN and LPS could use different activation mechanisms. It is noteworthy that neutralizing antibody to CD14 only partially (\u003c40%) inhibited dCGN-induced TNF secretion (not shown). TLR4 has been recently identified as a surface membrane receptor for CGN in human colonic epithelial cells [41]. Thus, it is possible that TLR4 is activated by dCGN to induce cytokine secretion by monocytes. We can only speculate that TLR4 may have a higher affinity-binding site for dCGN than for LPS, however, this hypothesis remains to be tested.\nAnother indicator that dCGN stimulate monocytes leading to a more active phenotype is the fact that surface expression of the adhesion molecule ICAM-1 was enhanced in both PBM and THP-1 cells. The over expression of ICAM-1 caused the activated monocytes to form cell aggregates that were more abundant among cells treated with the 40 kDa dCGN. This correlates with the higher expression of ICAM-1 induced by the 40 kDa dCGN, suggesting that the partially degraded CGN is more biologically active. In addition, the cell aggregates are reminiscent of monocyte aggregates, which form multinucleated giant cells (MGC) in patients with Crohn's disease [42]. These giant cells were not observed in healthy individuals or in patients with ulcerative colitis [42]. Moreover, increased expression levels of ICAM-1 and LFA-3 (CD58) were also detected in monocytes from patients with Crohn's disease [43], [44]. Thus, degraded CGN clearly can activate monocytes to express an increased number of ICAM-1 adhesion molecules, therefore being capable of creating the conditions characteristic of Crohn's disease symptomatology, i.e. PBM accumulation and MGC formation [45], [46].\nThe NF-κB pathway regulates genes responsible for ICAM-1 and TNF-α expression. NF-κB activation is associated with the degradation of the inhibitor protein IκB [47]. Indeed, dCGN induced NF-κB activation as shown by degradation of IκBα, translocation of p65 and p50 sub-units to the nucleus and by activation of an NF-κB-responsive luciferase reporter plasmid. Again, a stronger activation of NF-κB was induced by the 40 kDa dCGN compared to 10 kDa dCGN, suggesting that the partially degraded CGN is more biologically active. Our data are in agreement with a previous study showing that native CGN also induced activation of NF-κB in human colonic epithelial cells [48].\nNF-κB pathway is often associated to promote cell survival and cancer cell growth, however it has been sometimes reported to behave as a tumor suppressor, arresting cell proliferation [49]. Such relationship between NF-kB activation and cell cycle regulation has been reported in normal human epidermal cells [50]. Indeed, it has been shown that NF-κB activation suppressed cdk4 expression, which is necessary for the transition to S phase. Finally, NF-κB activation was reported to induce growth arrest in normal human keratinocytes by a mechanims involving the cdk inhibitor p21 [51]. The effects of dCGN on p21 and cdk4 expression remain to be studied.\nIn these studies, we have demonstrated a direct action of dCGN on monocytes. Monocytes exposed to dCGN acquired an inflammatory phenotype that included higher expression of the adhesion molecule ICAM-1 and TNF-α production, via the NF-κB pathway. This higher expression of ICAM-1 resulted in formation of cell aggregates similar to those observed in patients with Crohn's disease. We presume that the differential effects of 10 and 40 kDa dCGN to induce these effects on monocytes are tightly linked to their capacity to induce inflammation in vivo. However, in vivo, macrophages do not come in direct contact with the intestinal lumen and are separated by the epithelial barrier. The way by which dCGN may leave the intestinal lumen and cross the epithelial barrier to reach the macrophages is an intriguing open question. One possible explanation resides in the potential of dCGN to “induce” cellular and paracellular injurious effects at the intestinal epithelial cell monolayer [48].\nIn conclusion, dCGN inhibited THP-1 cell proliferation in vitro, accumulating the cells in the G1 phase of the cell cycle, increased ICAM-1 expression, stimulated ICAM-1-dependent monocyte aggregation in vitro, and stimulated TNF-α expression and secretion. These responses were more pronounced following 40 kDa dCGN, and were all linked to NF-κB activation. These results suggest that, although CGN is widely used as a food additive, its degraded forms have an important effect on monocytes characteristic of an inflammatory phenotype."}

GO-CC

GO-MF

{"project":"GO-MF","denotations":[{"id":"T15080","span":{"begin":2882,"end":2885},"obj":"http://purl.obolibrary.org/obo/GO_0004601"},{"id":"T15081","span":{"begin":4667,"end":4675},"obj":"http://purl.obolibrary.org/obo/GO_0003823"},{"id":"T15082","span":{"begin":5023,"end":5030},"obj":"http://purl.obolibrary.org/obo/GO_0005488"}],"text":"Discussion\nInflammation of the intestinal tract is usually associated with infiltration and activation of intestinal macrophages [17]. These macrophages are able to initiate immune responses and can be induced to differentiate into cells that either exacerbate or inhibit the inflammation. Accumulation of different types of leukocytes, including monocytes/macrophages, neutrophils, and lymphocytes in the intestinal mucosa during inflammation, is normally followed by secretion of pro-inflammatory cytokines [33]. Several stimuli can induce these leukocytes to produce and secrete cytokines during inflammation. One of the most potent and known stimuli for leukocyte activation is LPS from Gram-negative bacteria [34]. In addition, other factors are also able to stimulate cytokine secretion from various leukocytes [35], [36]. One such factor is CGN, a high molecular weight sulphated polysaccharide (\u003e200 kDa) derived from red algae (Rhodophyceae) [1], [2]. Native CGN is widely used as a food additive (E 407) to improve texture. It is also used in cosmetics and pharmaceuticals. Although native form CGN (200–800 kDa) has been declared harmless to humans [8], its degraded forms (\u003c50 kDa), also known as poligeenan, are widely used to induce colitis in rodents [3]–[5]. These degraded CGN may also have a possible carcinogenic effect [4], [6]–[8]; however this is still controversial.\nAlthough acid treatment at high temperature (80°C) is required for CGN hydrolysis in vitro to lower molecular weight dCGN, it is probable that some dCGN are produced by acid hydrolysis during gastric digestion [9], [10] or interaction with intestinal bacteria [11], [12]. Thus, understanding the mechanisms of dCGN-induced bowel inflammation is of great importance. In this report, we have analyzed the role of human monocytes (PBM and THP-1) in dCGN-induced inflammation.\nPreliminary in vivo studies in rats treated with dCGN revealed significant shortening of the large intestine associated with an inflammatory state, i.e. strong infiltration of macrophages to the intestinal mucosa similar to DSS-induced inflammation [20]. Using two fractions of dCGN (10 and 40 kDa), we observed a strong correlation between the severity of the inflammation and the dCGN molecular size, thus confirming the size related inflammation in vivo. This macrophage accumulation was not due to cell proliferation because dCGN inhibited THP-1 monocytes proliferation in vitro. These results are similar to those obtained with human colonic epithelial cells (NCM460 cell line) exposed to native CGN for 1–8 days [37]. Thus, it seems that dCGN promote macrophage infiltration by recruiting new cells to the inflamed intestinal mucosa and not by inducing cell proliferation. In addition, very few polymorphonuclear cells were detected in the mucosa at the time point analyzed as demonstrated by a very low level of MPO in the intestinal tissue.\nThese results suggest that monocytes might produce cytokines associated with activation into macrophages in response to dCGN. Thus, we analyzed the production of TNF by both PBM and THP-1 cells in response to dCGN. Degraded CGN induced a robust production of TNF by monocytes. The 40 kDa form of dCGN was more potent for monocyte stimulation than the 10 kDa or the native ones. Surprisingly, monocyte activation by dCGN to produce TNF was much stronger than the activation induced by LPS, an inflammatory factor considered to be among the most potent stimuli for leukocyte activation. These results underline the fact that partially degraded forms of CGN have important cellular effects. The amount of TNF secreted by PBM induced with LPS was much larger than the one secreted by THP-1 monocytes. Since monocyte activation by LPS is associated with the presence of the CD14 and TLR4 receptors [38]–[40], the different response observed could be due to the different expression of these receptors in PBM and THP-1 cells. CD14 is not expressed by THP-1 monocytes, but it is expressed by PBM. This fact could explain why THP-1 cells produced a much smaller response to LPS than PBM and also the difference of kinetics in the LPS induced TNF secretion. The peak of TNF response was observed after 8 h stimulation followed by a rapid decrease to baseline at 10 h, whereas on THP-1 cells the peak was not reached until after 56 h. Moreover, the amount of TNF secreted by monocytes induced with dCGN was much larger than the one induced by LPS. On the other hand, LPS and dCGN displayed a very different TNF secretion curve in THP-1 cells. These differences suggest that dCGN and LPS could use different activation mechanisms. It is noteworthy that neutralizing antibody to CD14 only partially (\u003c40%) inhibited dCGN-induced TNF secretion (not shown). TLR4 has been recently identified as a surface membrane receptor for CGN in human colonic epithelial cells [41]. Thus, it is possible that TLR4 is activated by dCGN to induce cytokine secretion by monocytes. We can only speculate that TLR4 may have a higher affinity-binding site for dCGN than for LPS, however, this hypothesis remains to be tested.\nAnother indicator that dCGN stimulate monocytes leading to a more active phenotype is the fact that surface expression of the adhesion molecule ICAM-1 was enhanced in both PBM and THP-1 cells. The over expression of ICAM-1 caused the activated monocytes to form cell aggregates that were more abundant among cells treated with the 40 kDa dCGN. This correlates with the higher expression of ICAM-1 induced by the 40 kDa dCGN, suggesting that the partially degraded CGN is more biologically active. In addition, the cell aggregates are reminiscent of monocyte aggregates, which form multinucleated giant cells (MGC) in patients with Crohn's disease [42]. These giant cells were not observed in healthy individuals or in patients with ulcerative colitis [42]. Moreover, increased expression levels of ICAM-1 and LFA-3 (CD58) were also detected in monocytes from patients with Crohn's disease [43], [44]. Thus, degraded CGN clearly can activate monocytes to express an increased number of ICAM-1 adhesion molecules, therefore being capable of creating the conditions characteristic of Crohn's disease symptomatology, i.e. PBM accumulation and MGC formation [45], [46].\nThe NF-κB pathway regulates genes responsible for ICAM-1 and TNF-α expression. NF-κB activation is associated with the degradation of the inhibitor protein IκB [47]. Indeed, dCGN induced NF-κB activation as shown by degradation of IκBα, translocation of p65 and p50 sub-units to the nucleus and by activation of an NF-κB-responsive luciferase reporter plasmid. Again, a stronger activation of NF-κB was induced by the 40 kDa dCGN compared to 10 kDa dCGN, suggesting that the partially degraded CGN is more biologically active. Our data are in agreement with a previous study showing that native CGN also induced activation of NF-κB in human colonic epithelial cells [48].\nNF-κB pathway is often associated to promote cell survival and cancer cell growth, however it has been sometimes reported to behave as a tumor suppressor, arresting cell proliferation [49]. Such relationship between NF-kB activation and cell cycle regulation has been reported in normal human epidermal cells [50]. Indeed, it has been shown that NF-κB activation suppressed cdk4 expression, which is necessary for the transition to S phase. Finally, NF-κB activation was reported to induce growth arrest in normal human keratinocytes by a mechanims involving the cdk inhibitor p21 [51]. The effects of dCGN on p21 and cdk4 expression remain to be studied.\nIn these studies, we have demonstrated a direct action of dCGN on monocytes. Monocytes exposed to dCGN acquired an inflammatory phenotype that included higher expression of the adhesion molecule ICAM-1 and TNF-α production, via the NF-κB pathway. This higher expression of ICAM-1 resulted in formation of cell aggregates similar to those observed in patients with Crohn's disease. We presume that the differential effects of 10 and 40 kDa dCGN to induce these effects on monocytes are tightly linked to their capacity to induce inflammation in vivo. However, in vivo, macrophages do not come in direct contact with the intestinal lumen and are separated by the epithelial barrier. The way by which dCGN may leave the intestinal lumen and cross the epithelial barrier to reach the macrophages is an intriguing open question. One possible explanation resides in the potential of dCGN to “induce” cellular and paracellular injurious effects at the intestinal epithelial cell monolayer [48].\nIn conclusion, dCGN inhibited THP-1 cell proliferation in vitro, accumulating the cells in the G1 phase of the cell cycle, increased ICAM-1 expression, stimulated ICAM-1-dependent monocyte aggregation in vitro, and stimulated TNF-α expression and secretion. These responses were more pronounced following 40 kDa dCGN, and were all linked to NF-κB activation. These results suggest that, although CGN is widely used as a food additive, its degraded forms have an important effect on monocytes characteristic of an inflammatory phenotype."}

GO-BP

2_test

pmc-enju-pas

bionlp-st-ge-2016-coref

{"project":"bionlp-st-ge-2016-coref","denotations":[{"id":"T13228","span":{"begin":3978,"end":3980},"obj":"Anaphor"},{"id":"T13229","span":{"begin":3932,"end":3936},"obj":"Antecedent"},{"id":"T13230","span":{"begin":7772,"end":7793},"obj":"Anaphor"},{"id":"T13231","span":{"begin":7794,"end":7800},"obj":"Antecedent"},{"id":"T13232","span":{"begin":8053,"end":8066},"obj":"Anaphor"},{"id":"T13233","span":{"begin":7851,"end":7857},"obj":"Antecedent"},{"id":"T13223","span":{"begin":3676,"end":3679},"obj":"Anaphor"},{"id":"T13224","span":{"begin":3614,"end":3617},"obj":"Antecedent"},{"id":"T13225","span":{"begin":3892,"end":3907},"obj":"Anaphor"},{"id":"T13226","span":{"begin":3781,"end":3785},"obj":"Antecedent"},{"id":"T13227","span":{"begin":3790,"end":3804},"obj":"Antecedent"}],"relations":[{"id":"R11419","pred":"boundBy","subj":"T13225","obj":"T13227"},{"id":"R11420","pred":"boundBy","subj":"T13228","obj":"T13229"},{"id":"R11421","pred":"boundBy","subj":"T13230","obj":"T13231"},{"id":"R11422","pred":"boundBy","subj":"T13232","obj":"T13233"},{"id":"R11417","pred":"boundBy","subj":"T13223","obj":"T13224"},{"id":"R11418","pred":"boundBy","subj":"T13225","obj":"T13226"}],"namespaces":[{"prefix":"_base","uri":"https://bionlp.dbcls.jp/ontology/ge.owl#"}],"text":"Discussion\nInflammation of the intestinal tract is usually associated with infiltration and activation of intestinal macrophages [17]. These macrophages are able to initiate immune responses and can be induced to differentiate into cells that either exacerbate or inhibit the inflammation. Accumulation of different types of leukocytes, including monocytes/macrophages, neutrophils, and lymphocytes in the intestinal mucosa during inflammation, is normally followed by secretion of pro-inflammatory cytokines [33]. Several stimuli can induce these leukocytes to produce and secrete cytokines during inflammation. One of the most potent and known stimuli for leukocyte activation is LPS from Gram-negative bacteria [34]. In addition, other factors are also able to stimulate cytokine secretion from various leukocytes [35], [36]. One such factor is CGN, a high molecular weight sulphated polysaccharide (\u003e200 kDa) derived from red algae (Rhodophyceae) [1], [2]. Native CGN is widely used as a food additive (E 407) to improve texture. It is also used in cosmetics and pharmaceuticals. Although native form CGN (200–800 kDa) has been declared harmless to humans [8], its degraded forms (\u003c50 kDa), also known as poligeenan, are widely used to induce colitis in rodents [3]–[5]. These degraded CGN may also have a possible carcinogenic effect [4], [6]–[8]; however this is still controversial.\nAlthough acid treatment at high temperature (80°C) is required for CGN hydrolysis in vitro to lower molecular weight dCGN, it is probable that some dCGN are produced by acid hydrolysis during gastric digestion [9], [10] or interaction with intestinal bacteria [11], [12]. Thus, understanding the mechanisms of dCGN-induced bowel inflammation is of great importance. In this report, we have analyzed the role of human monocytes (PBM and THP-1) in dCGN-induced inflammation.\nPreliminary in vivo studies in rats treated with dCGN revealed significant shortening of the large intestine associated with an inflammatory state, i.e. strong infiltration of macrophages to the intestinal mucosa similar to DSS-induced inflammation [20]. Using two fractions of dCGN (10 and 40 kDa), we observed a strong correlation between the severity of the inflammation and the dCGN molecular size, thus confirming the size related inflammation in vivo. This macrophage accumulation was not due to cell proliferation because dCGN inhibited THP-1 monocytes proliferation in vitro. These results are similar to those obtained with human colonic epithelial cells (NCM460 cell line) exposed to native CGN for 1–8 days [37]. Thus, it seems that dCGN promote macrophage infiltration by recruiting new cells to the inflamed intestinal mucosa and not by inducing cell proliferation. In addition, very few polymorphonuclear cells were detected in the mucosa at the time point analyzed as demonstrated by a very low level of MPO in the intestinal tissue.\nThese results suggest that monocytes might produce cytokines associated with activation into macrophages in response to dCGN. Thus, we analyzed the production of TNF by both PBM and THP-1 cells in response to dCGN. Degraded CGN induced a robust production of TNF by monocytes. The 40 kDa form of dCGN was more potent for monocyte stimulation than the 10 kDa or the native ones. Surprisingly, monocyte activation by dCGN to produce TNF was much stronger than the activation induced by LPS, an inflammatory factor considered to be among the most potent stimuli for leukocyte activation. These results underline the fact that partially degraded forms of CGN have important cellular effects. The amount of TNF secreted by PBM induced with LPS was much larger than the one secreted by THP-1 monocytes. Since monocyte activation by LPS is associated with the presence of the CD14 and TLR4 receptors [38]–[40], the different response observed could be due to the different expression of these receptors in PBM and THP-1 cells. CD14 is not expressed by THP-1 monocytes, but it is expressed by PBM. This fact could explain why THP-1 cells produced a much smaller response to LPS than PBM and also the difference of kinetics in the LPS induced TNF secretion. The peak of TNF response was observed after 8 h stimulation followed by a rapid decrease to baseline at 10 h, whereas on THP-1 cells the peak was not reached until after 56 h. Moreover, the amount of TNF secreted by monocytes induced with dCGN was much larger than the one induced by LPS. On the other hand, LPS and dCGN displayed a very different TNF secretion curve in THP-1 cells. These differences suggest that dCGN and LPS could use different activation mechanisms. It is noteworthy that neutralizing antibody to CD14 only partially (\u003c40%) inhibited dCGN-induced TNF secretion (not shown). TLR4 has been recently identified as a surface membrane receptor for CGN in human colonic epithelial cells [41]. Thus, it is possible that TLR4 is activated by dCGN to induce cytokine secretion by monocytes. We can only speculate that TLR4 may have a higher affinity-binding site for dCGN than for LPS, however, this hypothesis remains to be tested.\nAnother indicator that dCGN stimulate monocytes leading to a more active phenotype is the fact that surface expression of the adhesion molecule ICAM-1 was enhanced in both PBM and THP-1 cells. The over expression of ICAM-1 caused the activated monocytes to form cell aggregates that were more abundant among cells treated with the 40 kDa dCGN. This correlates with the higher expression of ICAM-1 induced by the 40 kDa dCGN, suggesting that the partially degraded CGN is more biologically active. In addition, the cell aggregates are reminiscent of monocyte aggregates, which form multinucleated giant cells (MGC) in patients with Crohn's disease [42]. These giant cells were not observed in healthy individuals or in patients with ulcerative colitis [42]. Moreover, increased expression levels of ICAM-1 and LFA-3 (CD58) were also detected in monocytes from patients with Crohn's disease [43], [44]. Thus, degraded CGN clearly can activate monocytes to express an increased number of ICAM-1 adhesion molecules, therefore being capable of creating the conditions characteristic of Crohn's disease symptomatology, i.e. PBM accumulation and MGC formation [45], [46].\nThe NF-κB pathway regulates genes responsible for ICAM-1 and TNF-α expression. NF-κB activation is associated with the degradation of the inhibitor protein IκB [47]. Indeed, dCGN induced NF-κB activation as shown by degradation of IκBα, translocation of p65 and p50 sub-units to the nucleus and by activation of an NF-κB-responsive luciferase reporter plasmid. Again, a stronger activation of NF-κB was induced by the 40 kDa dCGN compared to 10 kDa dCGN, suggesting that the partially degraded CGN is more biologically active. Our data are in agreement with a previous study showing that native CGN also induced activation of NF-κB in human colonic epithelial cells [48].\nNF-κB pathway is often associated to promote cell survival and cancer cell growth, however it has been sometimes reported to behave as a tumor suppressor, arresting cell proliferation [49]. Such relationship between NF-kB activation and cell cycle regulation has been reported in normal human epidermal cells [50]. Indeed, it has been shown that NF-κB activation suppressed cdk4 expression, which is necessary for the transition to S phase. Finally, NF-κB activation was reported to induce growth arrest in normal human keratinocytes by a mechanims involving the cdk inhibitor p21 [51]. The effects of dCGN on p21 and cdk4 expression remain to be studied.\nIn these studies, we have demonstrated a direct action of dCGN on monocytes. Monocytes exposed to dCGN acquired an inflammatory phenotype that included higher expression of the adhesion molecule ICAM-1 and TNF-α production, via the NF-κB pathway. This higher expression of ICAM-1 resulted in formation of cell aggregates similar to those observed in patients with Crohn's disease. We presume that the differential effects of 10 and 40 kDa dCGN to induce these effects on monocytes are tightly linked to their capacity to induce inflammation in vivo. However, in vivo, macrophages do not come in direct contact with the intestinal lumen and are separated by the epithelial barrier. The way by which dCGN may leave the intestinal lumen and cross the epithelial barrier to reach the macrophages is an intriguing open question. One possible explanation resides in the potential of dCGN to “induce” cellular and paracellular injurious effects at the intestinal epithelial cell monolayer [48].\nIn conclusion, dCGN inhibited THP-1 cell proliferation in vitro, accumulating the cells in the G1 phase of the cell cycle, increased ICAM-1 expression, stimulated ICAM-1-dependent monocyte aggregation in vitro, and stimulated TNF-α expression and secretion. These responses were more pronounced following 40 kDa dCGN, and were all linked to NF-κB activation. These results suggest that, although CGN is widely used as a food additive, its degraded forms have an important effect on monocytes characteristic of an inflammatory phenotype."}

bionlp-st-ge-2016-spacy-parsed

UBERON-AE

sentences

events-check-again

bionlp-st-ge-2016-reference-tees

bionlp-st-ge-2016-reference

bionlp-st-ge-2016-uniprot

test2

PMC:2800179 / 29490-38613 JSONTXT

Annnotations TAB JSON ListView MergeView

PMC:2800179 / 29490-38613 JSON TXT