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Objective:To study the influence of circular RNA hsa_circZDHHC21_004 on the proliferation of human small intestinal epithelial cells HIEC-6 after 60Co γ-rays exposure. Methods:HIEC-6 cells were exposed to 60Co γ-rays at 0, 5, 10, and 15 Gy with a dose rate of 1 Gy/min. The expression level of hsa_circZDHHC21_004 in the irradiated HIEC-6 cell was detected. Hsa_circZDHHC21_004 was knocked-down to investigate the influences of hsa_circZDHHC21_004 on the proliferation of irradiated HIEC-6 cells by CCK-8 assay and colony formation assay. Results:The expression level of hsa_circZDHHC21_004 in HIEC-6 cells was upregulated by (1.00±0.24), (1.34±0.28), (1.85±0.31), and (2.80±0.64) times of control after 0, 5, 10, and 15 Gy irradiation, respectively and there were significant difference between 10 or 15 Gy group and 0 Gy group ( F=10.86, P=0.008). Knockdown of hsa_circZDHHC21_004 significantly increased the proliferation rate of HIEC-6 cells at 24, 48, and 72 h after 10 Gy irradiation compared with non-irradiated control ( t=-6.25, -5.83, -7.75, P < 0.001). Under 2 and 5 Gy irradiation, the clone formation rates of the hsa_circZDHHC21_004 knockdown cells were significantly higher than those of the control ( t=-7.45, -8.83, P<0.01). Conclusions:Hsa_circZDHHC21_004 is increased after irradiation and influenced the proliferation of irradiated HIEC-6 cells.
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Inflammatory bowel disease (IBD) is a group of chronic idiopathic colorectal inflammatory diseases with a progressive and unpredictable course, including ulcerative colitis (UC) and Crohn's disease (CD). Abnormal intestinal inflammation and immune response contribute to the pathogenesis of IBD. Autophagy as an essential catabolic process in cells, has been demonstrated to have associations with a variety of inflammatory diseases including IBD. Here, we review the relationship between autophagy dysfunction and the process of IBD. The progress of several autophagy regulators for intestinal epithelial cells and macrophages is highlighted (inflammasome inhibitors, intestinal flora regulators, and other signal regulators) in the current studies on IBD.
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Objective:To investigate the role of cholinergic anti-inflammatory pathway in the regulation of peptide transporter 1 (PepT1) expression in small intestinal epithelium of septic rats by Ghrelin.Methods:One hundred adult male Sprague-Dawley (SD) rats were randomly divided into sham operation group, sepsis group, sepsis+vagotomy group, sepsis+Ghrelin group, and sepsis+vagotomy+Ghrelin group, with 20 rats in each group. In the sham operation group, the cecum was separated after laparotomy, without ligation and perforation. In the sepsis group, the rats received cecal ligation puncture (CLP). In the sepsis+vagotomy group, the rats received CLP and vagotomy after laparotomy. In the sepsis+Ghrelin group, 100 μmol/L Ghrelin was intravenously injected after CLP immediately. The rats in the sepsis+vagotomy+Ghrelin group received CLP and vagotomy at the same time, then the Ghrelin was intravenously injected immediately with the same dose as the sepsis+Ghrelin group. Ten rats in each group were taken to observe their survival within 7 days. The remaining 10 rats were sacrificed 20 hours after the operation to obtain venous blood and small intestinal tissue. The condition of the abdominal intestine was observed. The injury of intestinal epithelial cells was observed with transmission electron microscopy. The contents of tumor necrosis factor-α (TNF-α) and interleukin-1β (IL-1β) in serum and small intestinal tissue were detected by enzyme-linked immunosorbent assay (ELISA). The brush border membrane vesicle (BBMV) was prepared, the levels of mRNA and protein expression of PepT1 in the small intestinal epithelium were detected by real-time fluorescence quantitative polymerase chain reaction (RT-qPCR) and Western blotting.Results:All rats in the sham operation group survived at 7 days after operation. The 7-day cumulative survival rate of rats in the sepsis group was significantly lower than that in the sham operation group (20% vs. 100%, P < 0.05). The cumulative survival rate of rats after Ghrelin intervention was improved (compared with sepsis group: 40% vs. 20%, P < 0.05), but the protective effect of Ghrelin was weakened after vagotomy (compared with sepsis+Ghrelin group: 10% vs. 40%, P < 0.05). Compared with the sham operation group, in the sepsis group, the small intestine and cecum were dull red, the intestinal tubules were swollen and filled with gas, the intestinal epithelial cells were seriously injured under transmission electron microscopy, the levels of TNF-α and IL-1β in serum and small intestinal were significantly increased, and the expression levels of PepT1 mRNA and protein in the small intestinal epithelium were significantly decreased. It indicated that the sepsis rat model was successfully prepared. After vagotomy, the intestinal swelling and gas accumulation became worse in septic rats, leading to the death of all rats. Compared with the sepsis group, the abdominal situation in the sepsis+Ghrelin group was improved, the injury of intestinal epithelial cells was alleviated, the serum and small intestinal TNF-α and IL-1β were significantly decreased [serum TNF-α (ng/L): 253.27±23.32 vs. 287.90±19.48, small intestinal TNF-α (ng/L): 95.27±11.47 vs. 153.89±18.15, serum IL-1β (ng/L): 39.16±4.47 vs. 54.26±7.27, small intestinal IL-1β (ng/L): 28.47±4.13 vs. 42.26±2.59, all P < 0.05], and the expressions of PepT1 mRNA and protein in the small intestinal epithelium were significantly increased [PepT1 mRNA (2 -ΔΔCt): 0.66±0.05 vs. 0.53±0.06, PepT1 protein (PepT1/GAPDH): 0.80±0.04 vs. 0.60±0.05, both P < 0.05]. Compared with the sepsis+Ghrelin group, after vagotomy in the sepsis+vagotomy+Ghrelin group, the effect of Ghrelin on reducing the release of inflammatory factors in sepsis rats was significantly reduced [serum TNF-α (ng/L): 276.58±19.88 vs. 253.27±23.32, small intestinal TNF-α (ng/L): 144.28±12.99 vs. 95.27±11.47, serum IL-1β (ng/L): 48.15±3.21 vs. 39.16±4.47, small intestinal IL-1β (ng/L): 38.75±4.49 vs. 28.47±4.13, all P < 0.05], the up-regulated effect on the expression of PepT1 in small intestinal epithelium was lost [PepT1 mRNA (2 -ΔΔCt): 0.58±0.03 vs. 0.66±0.05, PepT1 protein (PepT1/GAPDH): 0.70±0.02 vs. 0.80±0.04, both P < 0.05], and the injury of small intestinal epithelial cells was worse. Conclusion:Ghrelin plays a protective role in sepsis by promoting cholinergic neurons to inhibit the release of inflammatory factors, thereby promoting the transcription and translation of PepT1.
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It was found that intestinal flora could directly regulate mitochondria of intestinal epithelial cells or indirectly through the nucleus. This effect is associated with the flora metabolites such as short-chain fatty acids (SCFAs), hydrogen sulfide (H2S) and nitric oxide (NO). These metabolites are involved in mitochondria-related energy metabolic processes and the production of mitochondrial reactive oxygen species (mtROS), and even in the immune response of the whole organism. Numerous studies have also shown that intestinal flora metabolites and mitochondria have become a hot spot for research on the mechanism of action of traditional Chinese medicine, but the research on the mechanism of association between them is not yet in-depth. In this review, we summarize the mechanism of mitochondrial regulation of intestinal epithelial cells by intestinal flora metabolites and herbal interventions to provide a theoretical basis for targeting intestinal microbes and mitochondria to regulate body metabolism and health.
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Objective To explore the mechanism of the intestinal barrier damage caused by Blastocystis hominis infections in rats. Methods Thirty SD rats were randomly divided into the control group, and the 1-, 3-, 6- and 9-week-infection groups, of 6 rats in each group. Rats in each infection group were orally infected with B. hominis trophozoites at a density of 2 × 108 parasites per rat, and the control group was given an equal volume of phosphate buffered saline solution. The 7-hour urine samples were collected 1, 3, 6 and 9 weeks post-infection for the measurement of the intestinal permeability. Then, rats were sacrificed using the cervical dislocation method, and the cecum specimens were collected for the detection of the intestinal epithelial cell permeability. The expression of tight junction-related Occludin and Claudin - 1 genes and apoptosis-related Bcl - 2 and Bax genes was quantified in cecum epithelial cells using the real-time fluorescent quantitative PCR (qPCR) assay, and cell apoptosis was detected in the rat cecum using the TdT-mediated dUTP nick-end labeling (TUNEL) assay. Results The median urinary lactolose to mannitol ratios were 0.29, 0.72, 0.44, 0.46 and 0.38 in the control group, and the 1-, 3-, 6- and 9-week-infection groups, respectively, and the difference was statistically significant (H = 12.09, P < 0.05). B. hominis invasion and epithelial injury were observed in intestinal epithelial cells of rats infected with B. hominis, and transmission electron microscopy displayed the destruction of tight junctions between intestinal epithelial cells. The relative expression of Occludin, Claudin-1, Bcl-2 and Bax genes was 1.04, 0.62, 0.71, 0.68 and 0.96; 1.03, 0.61, 0.63, 0.76 and 0.86; 1.08, 0.70, 0.75, 0.74 and 1.03; and 1.00, 1.57, 1.33, 1.35 and 1.10 in the control group and the 1-, 3-, 6- and 9-week-infection groups, respectively, and all differences were statistically significant (F = 2.86, 2.85, 3.37 and 4.45, all P values < 0.05). The median number of positive staining cells were 1.00, 13.00, 9.00, 3.50 and 1.00 in rat cecum specimens in the control group, and the 1-, 3-, 6- and 9-week-infection groups, respectively, and the difference was statistically significant (H = 22.95, P < 0.01). Conclusion B. hominis infection may cause an increase in the rat intestinal permeability through triggering the apoptosis of intestinal epithelial cells to destroy the tight junction between intestinal epithelial cells, thereby destroying the intestinal barrier function.
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Objective To investigate the effect of miR-7 on the migration ability of intestinal epithelial cells and its related mechanisms. Methods LS174T cells were transfected with miR-7 mimic and miR-7 inhib-itor respectively. The effect of miR-7 on cell migration ability was detected by transwell chamber. The changes of PI3K, p-Akt and Akt protein in each group were detected by Western Blot. Results Compared with the control group, miRNA mimic negative control group and miRNA inhibitor negative control group, the number of cells in the miR-7 mimic group through the tranwell chamber decreased, the cell migration rate decreased, and the expression of PI3K and p-Akt protein decreased at the same time, the difference was statistically signifi-cant (P<0. 05). In the miRNA inhibitor group, the number of cells in the tranwell chamber increased, the cell migration rate increased, and the expression of PI3K and p-Akt protein was increased at the same time, the difference was statistically significant (P<0. 05). Conclusion miR-7 can inhibit the migration of LS174T cells, which may be through the regulation of the PI3K/Akt signaling pathway.
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Astragalus membranaceus (Radix Astragali, RA) and Atractylodes macrocephala (Rhizoma Atractylodis Macrocephalae, RAM) are often used to treat gastrointestinal diseases. In the present study, we determined the effects of polysaccharides extracts from these two herbs on IEC-6 cell migration and explored the potential underlying mechanisms. A migration model with IEC-6 cells was induced using a single-edged razor blade along the diameter of cell layers in six-well polystyrene plates. The cells were grown in control media or media containing spermidine (5 μmol·L, SPD), alpha-difluoromethylornithine (2.5 mmol·L, DFMO), 4-Aminopyridine (40 μmol·L, 4-AP), the polysaccharide extracts of RA or RAM (50, 100, or 200 mg·L), DFMO plus SPD, or DFMO plus polysaccharide extracts of RA or RAM for 12 or 24 h. Next, cytosolic free Ca ([Ca]) was measured using laser confocal microscopy, and cellular polyamine content was quantified with HPLC. Kv1.1 mRNA expression was assessed using RT-qPCR and Kv1.1 and RhoA protein expressions were measured with Western blotting analysis. A cell migration assay was carried out using Image-Pro Plus software. In addition, GC-MS was introduced to analyze the monosaccharide composition of both polysaccharide extracts. The resutls showed that treatment with polysaccharide extracts of RA or RAM significantly increased cellular polyamine content, elevated [Ca] and accelerated migration of IEC-6 cells, compared with the controls (P < 0.01). Polysaccharide extracts not only reversed the inhibitory effects of DFMO on cellular polyamine content and [Ca], but also restored IEC-6 cell migration to control level (P < 0.01 or < 0.05). Kv1.1 mRNA and protein expressions were increased (P < 0.05) after polysaccharide extract treatment in polyamine-deficient IEC-6 cells and RhoA protein expression was increased. Molar ratios of D-ribose, D-arabinose, L-rhamnose, D-mannose, D-glucose, and D-galactose was 1.0 : 14.1 : 0.3 : 19.9 : 181.3 : 6.3 in RA and 1.0 : 4.3 : 0.1 : 5.7 : 2.8 : 2.2 in RAM. In conclusion, treatment with RA and RAM polysaccharide extracts stimulated migration of intestinal epithelial cells via a polyamine-Kv1.1 channel activated signaling pathway, which facilitated intestinal injury healing.
Subject(s)
Animals , Rats , Astragalus propinquus , Chemistry , Atractylodes , Chemistry , Cell Line , Cell Movement , Drugs, Chinese Herbal , Chemistry , Pharmacology , Epithelial Cells , Cell Biology , Metabolism , Intestines , Cell Biology , Genetics , Metabolism , Polyamines , Metabolism , Polysaccharides , Chemistry , Pharmacology , Rhizome , Chemistry , Signal Transduction , rhoA GTP-Binding Protein , MetabolismABSTRACT
Astragalus membranaceus (Radix Astragali, RA) and Atractylodes macrocephala (Rhizoma Atractylodis Macrocephalae, RAM) are often used to treat gastrointestinal diseases. In the present study, we determined the effects of polysaccharides extracts from these two herbs on IEC-6 cell migration and explored the potential underlying mechanisms. A migration model with IEC-6 cells was induced using a single-edged razor blade along the diameter of cell layers in six-well polystyrene plates. The cells were grown in control media or media containing spermidine (5 μmol·L, SPD), alpha-difluoromethylornithine (2.5 mmol·L, DFMO), 4-Aminopyridine (40 μmol·L, 4-AP), the polysaccharide extracts of RA or RAM (50, 100, or 200 mg·L), DFMO plus SPD, or DFMO plus polysaccharide extracts of RA or RAM for 12 or 24 h. Next, cytosolic free Ca ([Ca]) was measured using laser confocal microscopy, and cellular polyamine content was quantified with HPLC. Kv1.1 mRNA expression was assessed using RT-qPCR and Kv1.1 and RhoA protein expressions were measured with Western blotting analysis. A cell migration assay was carried out using Image-Pro Plus software. In addition, GC-MS was introduced to analyze the monosaccharide composition of both polysaccharide extracts. The resutls showed that treatment with polysaccharide extracts of RA or RAM significantly increased cellular polyamine content, elevated [Ca] and accelerated migration of IEC-6 cells, compared with the controls (P < 0.01). Polysaccharide extracts not only reversed the inhibitory effects of DFMO on cellular polyamine content and [Ca], but also restored IEC-6 cell migration to control level (P < 0.01 or < 0.05). Kv1.1 mRNA and protein expressions were increased (P < 0.05) after polysaccharide extract treatment in polyamine-deficient IEC-6 cells and RhoA protein expression was increased. Molar ratios of D-ribose, D-arabinose, L-rhamnose, D-mannose, D-glucose, and D-galactose was 1.0 : 14.1 : 0.3 : 19.9 : 181.3 : 6.3 in RA and 1.0 : 4.3 : 0.1 : 5.7 : 2.8 : 2.2 in RAM. In conclusion, treatment with RA and RAM polysaccharide extracts stimulated migration of intestinal epithelial cells via a polyamine-Kv1.1 channel activated signaling pathway, which facilitated intestinal injury healing.
Subject(s)
Animals , Rats , Astragalus propinquus , Chemistry , Atractylodes , Chemistry , Cell Line , Cell Movement , Drugs, Chinese Herbal , Chemistry , Pharmacology , Epithelial Cells , Cell Biology , Metabolism , Intestines , Cell Biology , Genetics , Metabolism , Polyamines , Metabolism , Polysaccharides , Chemistry , Pharmacology , Rhizome , Chemistry , Signal Transduction , rhoA GTP-Binding Protein , MetabolismABSTRACT
Objective@#To investigate the effects of short chain fatty acid (SCFA) on barrier disruption of human intestinal epithelial cell induced by endotoxin/lipopolysaccharide (LPS) and the related mechanism.@*Methods@#The human intestinal epithelial cell line Caco-2 was used to reproduce monolayer-cells. Cells were divided into control group, LPS group, and SCFA+ LPS group according to the random number table. Cells in control group were only routinely cultured with DMEM medium. Cells in LPS group were cultured with DMEM medium and LPS with final mass concentration of 10 μg/mL. Cells in SCFA+ LPS group were cultured with DMEM medium, LPS and SCFA (consisting of 0.5 mmol/L acetate, 0.01 mmol/L propionate, and 0.01 mmol/L butyrate) with final mass concentration of 10 μg/mL. At post culture hour (PCH) 0, 1, 2, 6, 12, and 24, transepithelial electrical resistance (TER) of cells was determined with an ohmmeter, with sample number of 72. Another portion of cells were divided and treated as above, and then Western blotting was employed to detect the protein expressions of zonula occludens 1 (ZO-1), occludin, and claudin-1 at PCH 24, with sample number of 6. Another portion of cells were divided and treated as above and then immunofluorescence was used to observe cellular morphology and distribution of ZO-1. Data were processed with analysis of variance of factorial design, one-way analysis of variance, least-significant difference test, and Bonferroni correction.@*Results@#(1) Compared with that in control group, TER of cells in LPS group was significantly reduced from PCH 1 to 24 (P<0.01), while TER of cells in SCFA+ LPS group showed no obvious change (P>0.05). TER of cells in SCFA+ LPS group was significantly higher than that in LPS group from PCH 1 to 24 (P<0.01). (2) Compared with the protein expressions of ZO-1, occludin, and claudin-1 of cells in control group (1.25±0.10, 1.17±0.04, and 1.24±0.20), those of cells in LPS group (0.74±0.23, 0.76±0.11, and 0.77±0.11) at PCH 24 were significantly decreased (P<0.05), while those of cells in SCFA+ LPS group (1.23±0.46, 1.05±0.09, and 1.01±0.13) showed no significant differences (P>0.05). Protein expressions of occludin and claudin-1 of cells in SCFA+ LPS group were significantly higher than those in LPS group at PCH 24 (P<0.05). Protein expression of ZO-1 of cells in SCFA+ LPS group was higher than that in LPS group at PCH 24 with no significant difference (P>0.05). (3) At PCH 24, cells in control group were compact in arrangement with pebble-like appearance, and ZO-1 was distributed smoothly and continuously along the cell membrane. In LPS group, cells were sparse in arrangement with change in appearance, and ZO-1 was distributed uncontinuously along the cell membrane with curls and breaks. In SCFA+ LPS group, the appearance of cells and distribution of ZO-1 were remarkably ameliorated compared with those in LPS group.@*Conclusions@#SCFA can alleviate the barrier disruption of human intestinal epithelial cell induced by LPS through interdicting the abnormal distribution of ZO-1 and decrease of TER and tight junction proteins′ expressions.
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Objective To evaluate the blocking effect and mechanism of Soybean-derived Bowman-Birk inhibitor (BBI)on LPS-mediated downregulation for tight junction protein(HT-29 cells)in intestinal epithelial cells(IECs). Methods The toxic effect of LPS and BBI on HT-29 cells was detected by CCK8 Kit.HT-29 cells were pretreated by BBI for 6 hours prior to LPS stimulation, the expression of tight junction protein(ZO-1 and Occludin), TLR4, and MyDD8 was detected by the quantitative real-time polymerase chain reaction(PCR)and Western Blot;activation of NF-κB was measured by Western Blot.Results LPS(1 000ng/mL)and BBI(1 000μg/mL)showed no cytotoxicity on HT-29 cells.LPS could significantly upregulate the expression of TLR4 in HT-29 cells, the up-regulation had time-dose effect, and could significantly downregulate the expression of tight junction protein, the down-regulation effect was directly proportional to the concentration of LPS, could activate NF-κB, and had dose effect, effect of LPS on HT-29 cells could be significantly inhibited by BBI.Conclusion By inhibiting the expression of TLR4 and activation of NF-κB in IECs induced by LPS, BBI can significantly block the LPS-mediated inhibitory effect on tight junction protein in intestinal epithelial cells.
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The aim of this study is to construct the expression vector of zot gene of Vibrio cholerae and to realize the expression of zot gene of Vibrio cholerae in E.coli and study the biological activity of its recombinant expression product.In order to express zot protein in E.coli,the full-length open reading frame of zot was amplified by PCR from the standard strains of Vibrio cholerae MO45 genome DNA.The PCR product was cloned into prokaryotic expression vector pET-32a(+) with restriction enaymes Bam H I and XhoI.The recombinant vector pET-32a(+)-zot was transformed into E.coli BL21 (DE3) and expressed by IPTG induction.The zot fusion protein was detected by SDS-PAGE and Western blotting and purified by Ni-NTA affinity chromatography.After expression and purification,the recombinant expression protein played as a target for human small intestinal epithelial cells.Restriction endonuclease digestion,PCR and DNA sequencing analysis showed that the zot gene of 1 200 bp was amplified from Vibrio cholerae DNA,and the recombinant plasmid pET-32a(+)-zot was constructed and detected its expression in prokaryotic cell successfully with SDS-PAGE and Western blot techniques.The zot recombinant protein was successfully expressed and purified.The purified zot recombinant protein can cause human intestinal epithelial cells apoptosis.
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A healthy gut consists of commensal flora,epithelial layer and gut-associated lymphoid tissue (GALT). GALT is hyporesponsive to commensal flora and dietary antigens,but can recognize and at-tack pathogens. Accumulating evidence suggests that dendritic cells (DCs) play a crucial role in managing this paradoxical situation and maintaining the complex homeostasis in gut. Influenced by intestinal epithelial cells (IECs) and commensal flora,intestinal DCs possess unique properties that enable them to regulate T-helper 2 (Th2) cells,regulatory T cells (Tregs) and immunoglobulin A (IgA)-producing cells in a steady state. During infection,intestinal DCs are involved in the induction of effector lymphocytes, although they are also responsible for initiating pathogenic responses in inflammatory bowel diseases (IBDs). Therefore, intestinal DCs are associated with not only the maintenance of immune tolerance to commensal flora,but also the induction of protective immune responses against pathogens. This review outlines the roles of commensal flora, epithelial layer, and GALT in mucosal homeostasis and inflammation and summarizes recent progress in DCs-mediated intestinal immune homeostasis.
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Objective To investigate the inhibitory effect and mechanism of soybean-derived Bowman-Birk inhibi-tor (BBI)on LPS-induced expression of inflammatory cytokines in intestinal epithelial cells.Methods Cytotoxicity effect of LPS and BBI on intestinal epithelial cells was analyzed by MTT assay.Intestinal epithelial cells were pre-treated with BBI,followed by LPS stimulation,expression of inflammatory cytokines(TNF-α,IL-1β,IL-8,and MCP-1)was detected by quantitative real-time polymerase chain reaction;the activation of NF-κB was measured by pNF-κB-luc system and Western Blot.Results The maximum concentration of LPS (10000 ng/mL)and BBI (1000 μg/mL)had no cytotoxicity effect on intestinal epithelial cells.LPS could potently up-regulate the expression of inflammatory cytokines(TNF-α,IL-1β,IL-8,and MCP-1 ),the up-regulation was positively correlated to the concentration of LPS;LPS-induced expression of inflammatory cytokines in intestinal epithelial cells could achieve the highest level,then decreased over time.The up-regulation of LPS on inflammatory cytokines in intestinal epi-thelial cells had dose-time effect;when intestinal epithelial cells were pretreated by BBI for 6 hours,the inhibitory effect of BBI on LPS-induced expression of inflammatory cytokines in intestinal epithelial cells was most obvious, and had dose-time effect.Conclusion BBI can potently inhibit LPS-induced expression of inflammatory cytokines through inhibiting NF-κB in intestinal epithelial cells.
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Objective To investigate the inhibitory effect and mechanism of soybean-derived Bowman-Birk inhibi-tor (BBI)on LPS-induced expression of inflammatory cytokines in intestinal epithelial cells.Methods Cytotoxicity effect of LPS and BBI on intestinal epithelial cells was analyzed by MTT assay.Intestinal epithelial cells were pre-treated with BBI,followed by LPS stimulation,expression of inflammatory cytokines(TNF-α,IL-1β,IL-8,and MCP-1)was detected by quantitative real-time polymerase chain reaction;the activation of NF-κB was measured by pNF-κB-luc system and Western Blot.Results The maximum concentration of LPS (10000 ng/mL)and BBI (1000 μg/mL)had no cytotoxicity effect on intestinal epithelial cells.LPS could potently up-regulate the expression of inflammatory cytokines(TNF-α,IL-1β,IL-8,and MCP-1 ),the up-regulation was positively correlated to the concentration of LPS;LPS-induced expression of inflammatory cytokines in intestinal epithelial cells could achieve the highest level,then decreased over time.The up-regulation of LPS on inflammatory cytokines in intestinal epi-thelial cells had dose-time effect;when intestinal epithelial cells were pretreated by BBI for 6 hours,the inhibitory effect of BBI on LPS-induced expression of inflammatory cytokines in intestinal epithelial cells was most obvious, and had dose-time effect.Conclusion BBI can potently inhibit LPS-induced expression of inflammatory cytokines through inhibiting NF-κB in intestinal epithelial cells.
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Objective To evaluate the effects and mechanisms of bovine lactoferrin(bLF)on cell viability,proliferation,and the protective roles in intestinal epithelial cell-6(IEC-6)treated by lipopolysaccharide(LPS).Methods The rat jejunum epithelial cell lines IEC-6 were cultured in vitro.The effects of bLF on cell viability and proliferation in IEC-6 cells were detected by 3-(4,5-dimethyl-2-thiazolyl)-2,5-diphenyl-2-H-tetrazolium bromide(MTT)assay and 5-Bromo-deoxyuridine(Brdu)assay,respectively.Inflammatory cytokines and their mRNA of interleukin-1β(IL-1β),interleukin-6(IL-6),tumor necrosis factor-α(TNF-α)and interleukin-8(IL-8)were analyzed by real-time PCR and enzyme-linked immunosorbent assay(ELISA).Western blot was used to measure the levels of mitogen-activated protein kinase(MAPK)activation and nuclear factor kappa β(NF-κB)nuclear translocation.Results Dose dependent effects of bLF on cell viability and proliferation were observed in IEC-6 cells in vitro(F=3.825,5.861,all P<0.05),especially in a dose of 100 mg/L,and bLF significantly stimulated cell viability and proliferation compared with non-treatment group(q=5.240,3.765,all P<0.05).The mRNA levels of IL-1β,IL-6 and TNF-α were decreased by co-stimulation of bLF and LPS compared with the LPS treatments alone in IEC-6 cells in vitro(q=14.28,10.12,16.45,all P<0.001).The secretion of IL-6 and TNF-α was also decreased by co-stimulation of bLF and LPS(q=15.06,6.74,all P<0.01).In vitro,bLF treatment at dose of 100 mg/L could inhibit the activation of MAPK/NF-κB signal pathway induced by LPS(q=12.96,18.54,all P<0.001).Conclusion In vitro,bLF can promote IEC-6 viability and proliferation,and have anti-inflammatory effects via inhibited activation of MAPK/NF-κB nuclear translocation.
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Objective To investigate the effects of hydrogen-rich medium on lipopolysaccharide (LPS)-induced intestinal epithelial barrier dysfunction of human intestinal epithelial (Caco2) cells. Methods Caco2 cells (passages 28-35) were purchased from the Cell Bank of the Shanghai Institute of Cell Biology, Chinese Academy of Sciences in Shanghai, China, and they were cultured in Dulbecco minimum essential medium (DMEM) containing 20% fetal bovine serum. These cells were randomly divided into four groups: control group (group A), hydrogen-rich medium group (group B), LPS group (group C) and LPS + hydrogen-rich medium group (group D). Cells were cultured with normal medium in group A and group C or with hydrogen-rich medium in group B and group D. Meanwhile, 1 g/L LPS was simultaneously added into group C and group D, while an equivalent volume of normal saline was added into group A and group B instead. In vitro intestinal epithelial models were reproduced with monolayer filter-grown Caco2 and intestinal epithelium. The trans-epithelial electrical resistance (TEER) in models of each group was measured at different incubation times (0, 3, 6, 12, 24 and 48 hours). Cell viability and cytotoxicity were assessed with 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay and lactate dehydrogenase (LDH) release assay, respectively, after incubation for 24 hours. The expression levels of claudin-1 and occludin were respectively determined at 6, 12 and 24 hours of incubation by Western Blot assay. The morphological structure of claudin-1 and occludin was respectively observed after incubation for 24 hours with immunofluorescence staining. Results There was no statistical significance in variables between group A and group B. Compared with group A, it was shown that TEER was time-dependently decreased in groups C and D after 6 hours. Compared with group C, TEER in group D was increased after 6 hours. Compared with group A, the cell viability was significantly reduced in group C [(67.2±7.9)% vs. (100.0±0.0)%, P < 0.05] and cell injury was obvious [LDH release rate: (38.5±2.1)% vs. (1.2±0.3)%, P < 0.05]; the expression levels of claudin-1 and occludin at 6, 12, 24 hours were significantly down-regulated [claudin-1 (gray value): 0.351±0.079, 0.272±0.075, 0.190±0.049 vs. 0.518±0.030; occludin (gray value): 0.416±0.044, 0.290±0.062, 0.226±0.019 vs. 0.602±0.038, all P < 0.05], and the structure of claudin-1 and occludin were profoundly disrupted. Compared with group C, it was shown that the cell viability was significantly increased in group D [(88.8±7.4)% vs. (67.2±7.9)%, P < 0.05] and cell injury was significantly abated [LDH release rate: (16.4±4.3)% vs. (38.5±2.1)%, P < 0.05]; the expression levels of claudin-1 and occludin were significantly up-regulated at 24 hours [claudin-1 (gray value): 0.428±0.046 vs. 0.190±0.049, occludin (gray value): 0.466±0.071 vs. 0.226±0.019, both P < 0.05]; the disrupted structures of claudin-1 and occludin were partially recovered. Conclusion Hydrogen-rich medium can effectively attenuate LPS-induced dysfunction of intestinal epithelial barrier in human Caco2 cells by ameliorating cell viability as well as regulating claudin-1 and occludin expression and structure.
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Objective: To study the effect of Astragalus membranaceus polysaccharides (AMP) on migration, intracellular polyamines content, cytosolic free Ca2+ concentration ([Ca2+]cyto), and RhoA protein expression of intestinal epithelial (IEC-6) cells, so as to explore the repairing mechanism of Astragalus membranaceus (AM) on gastrointestinal injury. Methods: AM was extracted by water and precipitated by ethanol, AM crude polysaccharides were obtained after removing protein. AMP I, II, III, and IV were obtained by DEAE cellulose column chromatography. AMP V was further obtained by Sephadex LH-20 gel column chromatography from AMP I. Cell migration model was established by Tips scratch method; High performance liquid chromatography was used to determine the polyamines content; Flow cytometry was used to detect the [Ca2+]cyto; Western blotting analysis was used to detect RhoA protein expression. The improving effect of AMP on migration, [Ca2+]cyto, and RhoA protein expression of normal and polyamine-depleted IEC-6 cells was observed. Results: AM crude polysaccharides, AMP I, and AMP V (100 mg /L or 200 mg /L) promoted cell migration and reversed the inhibition of cell migration induced by DFMO (P < 0.01); AMP V increased the intracellular polyamines content in normal and polyamine-deficient IEC-6 cells; AMP V also enhanced [Ca2+]cyto in the process of IEC-6 cell migration and reversed the reduction of [Ca2+]cyto induced by DFMO (P < 0.01); Further study suggested that AMP V increased RhoA protein expression in normal and polyamine-deficient IEC-6 cells (P < 0.01). Conclusion: These results indicate that the repairing effect of AM on the gastrointestinal mucosa damage may be related to its role of increasing polyamines content, then improving [Ca2+]cyto and RhoA protein expression and thereby promoting cell migration.
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Aims To observe the effect of saccharide extracts of Yiqijianpi herb Codonopsis and Glycyrrhizae on polyamine-dependent activation of K+ channels sig-nal pathway during cell migration and to investigate their mechanism of promoting restoration in gastrointes-tinal mucosal injuries. Method The study was based on IEC-6 cell migration model. While in a normal polyamine level or polyamine was inhibited by DFMO, the effect of Codonopsis saccharide extracts and Glycyr-rhizae saccharide extracts on polyamine-dependent acti-vation of K+ channels signal pathway during cell mi-gration was observed. (1) K+ channel protein Kv1. 1 was determined by Western blot. (2)Membrane poten-tial was measured by Flow Cytometer. (3) Laser scan-ning confocal microscope was used for measuring [ Ca2+] cyt. ( 4 ) The expression of RhoA, which is Ca2+ downstream protein, was determined by Western blot. Results During cell migration, Codonopsis and Glycyrrhizae saccharide extracts could: ( 1 ) improve the expression of Kv1 . 1 protein and ameliorate the de-crease of kv1. 1 protein expression by DFMO;(2) in-crease membrane hyperpolarization and reverse mem-brane depolarization resulted by DFMO; ( 3 ) improve intracellular [ Ca2+] cyt, while Codonopsis could re-verse the decrease of [ Ca2+] cyt caused by DFMO;(4) improve the expression of RhoA protein, reversing its decline caused by DFMO. Conclusion Codonop-sis and Glycyrrhizae saccharide extracts can promote cell migration in IEC-6 cell, which is correlated with their effect on polyamine-dependent activation of K+channels signal pathway.
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Objective To detect the effects of bifidobacterium or bifidobacterium cultured supernatant on the mRNA expression of tumor necrosis factor receptor-associated factor 6 (TRAF6),glycogen synthase kinase-3β (GSK-3β) and the miRNA-146a in rat small intestinal epithelial cell(IEC-6) induced by lipopolysaccharide (LPS).Methods IEC-6 in logarithmic phase were randomly divided into LPS group,cultured supernatant group and inactivated bacteria group.All the 3 groups were exposed to 5 mg/L LPS for 5 hours,and then 1 mL sterile saline was added in LPS group and culturing continued for 24 hours ; 1 mL bifidobacterium cultured supernatant was added in cultured supernatant group and culturing continued for 24 hours;1 mL inactivated bifidobacterium 1 x 1010 CFU/L added in inactivated bacteria group and continued culturing for 24 hours.The mRNA expressions of TRAF6,GSK-3 β and miRNA-146a were detected by reverse transcription-polymerase chain reaction (RT-PCR).Results The level of TRAF6,GSK-3 β of culture supematant group (0.72 ± 0.05,0.46 ± 0.14) were all lower than LPS group (1.01 ± 0.14,1.02 ± 0.25),but the level of miRNA-146a(3.05 ± 0.40) was higher than that in LPS group(1.01 ± 0.12),and there were significant differences between them (t =5.278,6.316,13.218,P =0.000).The level of GSK-3 β of inactivated bacteria group(0.59 ±0.13) was significantly lower than that in LPS group(t =4.837,P =0.000).The levels of TRAF6 and miRNA-146a of inactivated bacteria group(1.05 ±0.11,0.78 ±0.22) had no significant differences with LPS group (t =0.732,1.463,P ＞ 0.05).The level of TRAF6 of cultured supernatant group was lower than that in inactivated bacteria group,and the level of miRNA-146a was higher than that in inactivated bacteria group,and there were significant differences between 2 groups (t =6.009,14.687,P =0.000).Conclusions Bifidobacterium cultured supernatant and inactivated bacteria both have certain protective effect on the IEC-6 induced by LPS.One of the protective mechanisms of bifidobacterium cultured supernatant may be achieved by elevating the expression of miRNA-146a,and decreasing the levels of inflammation related factor TRAF6 and damage related factor GSK-3β.The protective effects of inactivated bifidobacterium may be achieved by decreasing the level of damage related factor GSK-3β.
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Objective To investigate the effects of lipopolysaccharides (LPS) in different concentrations on the proliferation and interleukin(IL)-6,IL-1 β and tumor necrosis factor-α(TNF-o) secretion of intestinal epithelial cells (IEC-6) of rats in vitro.Methods IEC-6 of rats were divided into normal group (0 mg/L,group A),0.1 mg/L group (group B),0.5 mg/L group (group C),1.0 mg/L group (group D),5.0 mg/L group (group E) and 10.0 mg/L group(group F).Different groups cells were exposed to LPS with different concentrations for 3 h,5 h and 7 h.Thiazolyl blue(MTT) was performed to investigate the proliferation of IEC-6.The concentrations of IL-6,IL-1 β and TNF-α in culture supernatant were detected by enzyme linked immunosorbent assay(ELISA).Results The proliferation rate of IEC-6 was gradually lower while the concentration of LPS increased.After co-culture with LPS 3h and 5 h,the proliferation rates of group B,group C,group D,group E and group F had no significant difference with those of group A (all P ＞ 0.05);after co-culture with LPS 7 h,the proliferation rates of group B,group C,and group D had no significant difference with those of group A (all P ＞ 0.05);the proliferation rates of group E and group F had significant difference with those of group A(t =4.216,P =0.014;t =14.991,P =0.000).The proliferation rates of group E and group F were lower after co-culture with LPS 5 h than 7 h,and there were significant differences (t =2.576,P =0.033;t =2.975,P =0.018);but there was no significant differences between group E and group A after co-culture with LPS 5 h (P ＞ 0.05).Group B,group C,group D,group E and group F all had a significant higher level of IL-6 than group A after co-culture with LPS 3 h,5 h and 7 h(all P ＜0.01).In addition,group E had the highest level of IL-6 at all time points.And the peak level of IL-6 rose after co-culture with LPS 5 h.The TNF-α level and IL-1 β level of group B,group C,group D,group E and group F all had no significant differences than that of group A after co-culture with LPS 3 h,5 h and 7 h (all P ＞ 0.05).Conclusions In a certain concentration,incubation time range,the proliferation rates of IEC-6 cells were gradually lower while the concentration of LPS increased.Co-cultured IEC-6 cells with LPS(0-10.0 mg/L) can stimulate them secrete to IL-6.The highest level of IL-6 was of group E after 5 h co-culture.LPS had no effects on TNF-α and IL-1 β level of IEC-6 cells cultural supernatant.So 5.0 mg/L concentration of LPS stimulating IEC-6 cells for 5 h can be chosen to build the IEC-6 inflammatory models.