AIM To study the uptake of bacterial lipopolysaccharides (LPS) and expression of tumor necrosis factor α mRNA (TNF α mRNA) with cultured rat intrahepatic bile duct epithelial cells.
Summary: To investigate the role of NF-κB in endotoxic shock in rats, the model of endotoxin-shock rats was induced by intravenous infusion of lipopolysaccharide (LPS). 1 h, 2 h, 4 h and 6 h after LPS injection, the...Summary: To investigate the role of NF-κB in endotoxic shock in rats, the model of endotoxin-shock rats was induced by intravenous infusion of lipopolysaccharide (LPS). 1 h, 2 h, 4 h and 6 h after LPS injection, the activation of NF-κB in blood mononuclear cells and the content of TNF-α and IL-6 in plasma was detected by enzyme-linked immunoadsordent assay (ELISA). The level of mean arterial pressure (MAP) and the histopathological changes of lung and liver were also observed. The activation of NF-κB in mononuclear cells increased 1 h after LPS injection and reached its peak 2 h after the injection, and its level was higher than that of normal group. The level of TNF-α was increased 1 h after the infusion and peaked 2 h after the injection, and its level was higher than that of normal group after LPS infusion. The content of IL-6 increased gradually with time, the IL-6 level was higher than that of normal group after LPS injection. MAP was decreased gradually with time and its level was lower than that of normal group after LPS injection. Pathological examination showed that endotoxic shock could cause pulmonary alveolar hemorrhage, edema and infiltration of inflammatory cell in lung tissue and congestion, edema, capillary dilation and inflammatory cell infiltration in liver tissue. It is concluded that NF-κB can up-regulate the expression of TNF-α and IL-6 in plasma and play an important role in endotoxin-induced shock in rats.展开更多
Objective: To investigate the hepatoprotective effect of Xijiao Dihuang Decoction(犀角地黄汤,XJDHD) on lipopolysaccharide(LPS)-and tumor necrosis factor alpha(TNF-α)-induced acute liver failure(ALF)as well as the und...Objective: To investigate the hepatoprotective effect of Xijiao Dihuang Decoction(犀角地黄汤,XJDHD) on lipopolysaccharide(LPS)-and tumor necrosis factor alpha(TNF-α)-induced acute liver failure(ALF)as well as the underlying mechanism of action, and to clarify the key herbs and components of XJDHD. Methods:LPS/D-galactosamine(D-GalN) or TNF-α/D-GalN were intraperitoneally injected into C57BL/6J mice to induce ALF. Simultaneously, XJDHD or its individual herbs and components were orally administered. Survival rates, transaminase levels in serum, and hepatic histology were examined to evaluate the effects of XJDHD.The terminal deoxynucleotidyl transferase-mediated dUTP nick end labeling(TUNEL) assay and real-time polymerase chain reaction were additionally performed to expound the mechanism underlying the anti-apoptotic activity of XJDHD. Results: Oral administration of XJDHD protected mice from lethal liver failure induced by LPS and TNF-α, with notable amelioration of liver injury in histology and a significant decrease in transaminase levels in serum. XJDHD signi?cantly inhibited apoptosis of hepatocytes and enhanced expression of the antiapoptosis genes, c-Flip, Iap1, Gadd45 b and A20(all P<0.05). In addition, Rehmannia glutinosa Libosch. was identi?ed as the key herb of XJDHD and galactose as the effective component of Rehmannia glutinosa Libosch.that protects against ALF. Conclusions: XJDHD inhibits TNF-α-induced apoptosis of hepatocytes by promoting the expression of nuclear factor κB-regulated anti-apoptotic genes. Rehmannia glutinosa Libosch. may be the most effective herb of XJDHD and galactose is an active component in this protection.展开更多
Cytokines are essential for hematopoiesis and immune responses, and play a key role in the defense against infections. Lipopolysaccharide ( LPS) is a potent inducer of the agents involved in the pathogenesis of inflam...Cytokines are essential for hematopoiesis and immune responses, and play a key role in the defense against infections. Lipopolysaccharide ( LPS) is a potent inducer of the agents involved in the pathogenesis of inflammation responses. Tumor necrosis factor-α ( TNF-α ) and interleukin-6 (IL-6) are two important proinflammatory展开更多
Background Surfactant protein A （SP-A） contributes to the regulation of sepsis-induced acute lung injury.In a previous study,we demonstrated the expression and localization of SP-A in the kidneys.The present study e...Background Surfactant protein A （SP-A） contributes to the regulation of sepsis-induced acute lung injury.In a previous study,we demonstrated the expression and localization of SP-A in the kidneys.The present study evaluated the effect of SP-A on lipopolysaccharide （LPS）-induced tumor necrosis factor-α （TNF-α） expression and its underlying mechanisms in the human renal tubular epithelial （HK-2） cells.Methods Indirect immunofiuorescence assay was used to detect SP-A distribution and expression in HK-2 cells.HK-2 cells were treated with various concentrations of LPS （0,0.1,1,2,5,and 10 mg/L） for 8 hours and with 5 mg/L LPS for different times （0,2,4,8,16,and 24 hours） to determine the effects of LPS on SP-A and TNF-α expression.Then,HK-2 cells were transfected with SP-A siRNA to analyze nuclear factor κB （NF-κB） P65 and TNF-α expression of HK-2 cells after LPS-treatment.Results Indirect immunofluorescence assay revealed that SP-A is localized to the membrane and cytoplasm of HK-2 cells.Interestingly,SP-A1/SP-A2 and TNF-α expression were found to be significantly increased in HK-2 cells upon LPS treatment.Transfection of LPS-treated HK-2 cells with SP-A siRNA resulted in significant increases in the levels of NF-κB P65 protein and TNF-α mRNA and protein compared to those in non-transfected LPS-treated HK-2 cells.Conclusion SP-A plays an important role in protecting cells against sepsis-induced acute kidney injury by inhibiting NF-κB activity to modulate LPS-induced increase in TNF-α expression.展开更多
Background Numerous studies have shown that reducing the level of tumor necrosis factor-alpha （TNFα） through the use of anti-TNF antibodies or soluble TNF receptor is a safe and efficacious treatment to inflammator...Background Numerous studies have shown that reducing the level of tumor necrosis factor-alpha （TNFα） through the use of anti-TNF antibodies or soluble TNF receptor is a safe and efficacious treatment to inflammatory diseases such as rheumatoid arthritis. Therefore, novel approaches to achieve this outcome are desired. The aim of this study was to investigate the characterization of a small molecule inhibitor, Y316, which blocks TNF mRNA upregulation and TNF production by lipopolysaccharides （LPS） stimulated monocytes. Methods Peripheral blood mononuclear cells （PBMC） from healthy volunteers were plated in 24-well plates and stimulated with LPS （1 pg/ml）, phorbol-12-myristate-13-acetate （PMA） （100 ng/ml）, zymosan （10 IJg/ml） and Tsst （100 ng/ml）. Supernatants were collected after 4-hour culture at 37℃, and quantitative determination of TNFα, interleukin-113 （IL-1β）, IL-6, IL-8, IL-10 and IL-2 production in the supernatants was performed by colorimetric enzyme-linked immunosorbent assay （ELISA）. Total RNA of PBMC was isolated and cytokine mRNA quantitation was performed by using a RNA level measuring kit （R ＆ D Systems）. PBMC were pretreated with Y316 （10 μmol/L, 1 μmol/L, 0.1 μmol/L, 0.01 μmol/L and 0.001 μmOl/L） or dimethyl sulfoxide at 37℃ for 10 minutes, and then stimulated with LPS or PMA, protein concentrations of p44.42, IKBa, P38 and Jun NH2-terminat kinase were determined by Western blotting. Cyclic adenosine-3＇,5＇-monophosphate （cAMP） of PBMC was measured by enzyme immunoassay kit （Amersham Pharmacia Biotech）. Results Y316 blocked TNF production and inhibited the upregulation of TNF mRNA levels in response to LPS, and also prevented the production of IL-1 and IL-6. In contrast, Y316 augmented the production of IL-10 in LPS-stimulated monocytes. Y316 failed to prevent the production of IL-2 and TNF in antigen-stimulated T cells, suggesting that its effects may be cell-type specific. Y316 prevented the phosphorylation and activation of the MAPK, ERK, and therefore appeared to mediate its effects on TNF by acting at an early point in the signaling cascade induced in response to LPS. There was no effect of Y316 on cAMP levels either alone or in the presence of LPS. Conclusions Y316 appears to be a small molecule inhibiting TNF production, which may act via a novel mechanism. Identification of the target of Y316 may lead to the development of alternative strategies for achieving selective cytokine inhibition.展开更多
文摘AIM To study the uptake of bacterial lipopolysaccharides (LPS) and expression of tumor necrosis factor α mRNA (TNF α mRNA) with cultured rat intrahepatic bile duct epithelial cells.
基金This project was supported by a grant from Hubei Province Science and Technology Foundation (2003AA301C51).
文摘Summary: To investigate the role of NF-κB in endotoxic shock in rats, the model of endotoxin-shock rats was induced by intravenous infusion of lipopolysaccharide (LPS). 1 h, 2 h, 4 h and 6 h after LPS injection, the activation of NF-κB in blood mononuclear cells and the content of TNF-α and IL-6 in plasma was detected by enzyme-linked immunoadsordent assay (ELISA). The level of mean arterial pressure (MAP) and the histopathological changes of lung and liver were also observed. The activation of NF-κB in mononuclear cells increased 1 h after LPS injection and reached its peak 2 h after the injection, and its level was higher than that of normal group. The level of TNF-α was increased 1 h after the infusion and peaked 2 h after the injection, and its level was higher than that of normal group after LPS infusion. The content of IL-6 increased gradually with time, the IL-6 level was higher than that of normal group after LPS injection. MAP was decreased gradually with time and its level was lower than that of normal group after LPS injection. Pathological examination showed that endotoxic shock could cause pulmonary alveolar hemorrhage, edema and infiltration of inflammatory cell in lung tissue and congestion, edema, capillary dilation and inflammatory cell infiltration in liver tissue. It is concluded that NF-κB can up-regulate the expression of TNF-α and IL-6 in plasma and play an important role in endotoxin-induced shock in rats.
基金Supported by the National Natural Science Foundation of China(No.81072766)Beijing Natural Science Foundation(No.7112066)215 Program from Beijing Public Health Bureau(No.2013-2-11)
文摘Objective: To investigate the hepatoprotective effect of Xijiao Dihuang Decoction(犀角地黄汤,XJDHD) on lipopolysaccharide(LPS)-and tumor necrosis factor alpha(TNF-α)-induced acute liver failure(ALF)as well as the underlying mechanism of action, and to clarify the key herbs and components of XJDHD. Methods:LPS/D-galactosamine(D-GalN) or TNF-α/D-GalN were intraperitoneally injected into C57BL/6J mice to induce ALF. Simultaneously, XJDHD or its individual herbs and components were orally administered. Survival rates, transaminase levels in serum, and hepatic histology were examined to evaluate the effects of XJDHD.The terminal deoxynucleotidyl transferase-mediated dUTP nick end labeling(TUNEL) assay and real-time polymerase chain reaction were additionally performed to expound the mechanism underlying the anti-apoptotic activity of XJDHD. Results: Oral administration of XJDHD protected mice from lethal liver failure induced by LPS and TNF-α, with notable amelioration of liver injury in histology and a significant decrease in transaminase levels in serum. XJDHD signi?cantly inhibited apoptosis of hepatocytes and enhanced expression of the antiapoptosis genes, c-Flip, Iap1, Gadd45 b and A20(all P<0.05). In addition, Rehmannia glutinosa Libosch. was identi?ed as the key herb of XJDHD and galactose as the effective component of Rehmannia glutinosa Libosch.that protects against ALF. Conclusions: XJDHD inhibits TNF-α-induced apoptosis of hepatocytes by promoting the expression of nuclear factor κB-regulated anti-apoptotic genes. Rehmannia glutinosa Libosch. may be the most effective herb of XJDHD and galactose is an active component in this protection.
文摘Cytokines are essential for hematopoiesis and immune responses, and play a key role in the defense against infections. Lipopolysaccharide ( LPS) is a potent inducer of the agents involved in the pathogenesis of inflammation responses. Tumor necrosis factor-α ( TNF-α ) and interleukin-6 (IL-6) are two important proinflammatory
基金This work was supported by grants from the National Natural Science Foundation of China （No. 81201457 and 81070556）.
文摘Background Surfactant protein A （SP-A） contributes to the regulation of sepsis-induced acute lung injury.In a previous study,we demonstrated the expression and localization of SP-A in the kidneys.The present study evaluated the effect of SP-A on lipopolysaccharide （LPS）-induced tumor necrosis factor-α （TNF-α） expression and its underlying mechanisms in the human renal tubular epithelial （HK-2） cells.Methods Indirect immunofiuorescence assay was used to detect SP-A distribution and expression in HK-2 cells.HK-2 cells were treated with various concentrations of LPS （0,0.1,1,2,5,and 10 mg/L） for 8 hours and with 5 mg/L LPS for different times （0,2,4,8,16,and 24 hours） to determine the effects of LPS on SP-A and TNF-α expression.Then,HK-2 cells were transfected with SP-A siRNA to analyze nuclear factor κB （NF-κB） P65 and TNF-α expression of HK-2 cells after LPS-treatment.Results Indirect immunofluorescence assay revealed that SP-A is localized to the membrane and cytoplasm of HK-2 cells.Interestingly,SP-A1/SP-A2 and TNF-α expression were found to be significantly increased in HK-2 cells upon LPS treatment.Transfection of LPS-treated HK-2 cells with SP-A siRNA resulted in significant increases in the levels of NF-κB P65 protein and TNF-α mRNA and protein compared to those in non-transfected LPS-treated HK-2 cells.Conclusion SP-A plays an important role in protecting cells against sepsis-induced acute kidney injury by inhibiting NF-κB activity to modulate LPS-induced increase in TNF-α expression.
文摘Background Numerous studies have shown that reducing the level of tumor necrosis factor-alpha （TNFα） through the use of anti-TNF antibodies or soluble TNF receptor is a safe and efficacious treatment to inflammatory diseases such as rheumatoid arthritis. Therefore, novel approaches to achieve this outcome are desired. The aim of this study was to investigate the characterization of a small molecule inhibitor, Y316, which blocks TNF mRNA upregulation and TNF production by lipopolysaccharides （LPS） stimulated monocytes. Methods Peripheral blood mononuclear cells （PBMC） from healthy volunteers were plated in 24-well plates and stimulated with LPS （1 pg/ml）, phorbol-12-myristate-13-acetate （PMA） （100 ng/ml）, zymosan （10 IJg/ml） and Tsst （100 ng/ml）. Supernatants were collected after 4-hour culture at 37℃, and quantitative determination of TNFα, interleukin-113 （IL-1β）, IL-6, IL-8, IL-10 and IL-2 production in the supernatants was performed by colorimetric enzyme-linked immunosorbent assay （ELISA）. Total RNA of PBMC was isolated and cytokine mRNA quantitation was performed by using a RNA level measuring kit （R ＆ D Systems）. PBMC were pretreated with Y316 （10 μmol/L, 1 μmol/L, 0.1 μmol/L, 0.01 μmol/L and 0.001 μmOl/L） or dimethyl sulfoxide at 37℃ for 10 minutes, and then stimulated with LPS or PMA, protein concentrations of p44.42, IKBa, P38 and Jun NH2-terminat kinase were determined by Western blotting. Cyclic adenosine-3＇,5＇-monophosphate （cAMP） of PBMC was measured by enzyme immunoassay kit （Amersham Pharmacia Biotech）. Results Y316 blocked TNF production and inhibited the upregulation of TNF mRNA levels in response to LPS, and also prevented the production of IL-1 and IL-6. In contrast, Y316 augmented the production of IL-10 in LPS-stimulated monocytes. Y316 failed to prevent the production of IL-2 and TNF in antigen-stimulated T cells, suggesting that its effects may be cell-type specific. Y316 prevented the phosphorylation and activation of the MAPK, ERK, and therefore appeared to mediate its effects on TNF by acting at an early point in the signaling cascade induced in response to LPS. There was no effect of Y316 on cAMP levels either alone or in the presence of LPS. Conclusions Y316 appears to be a small molecule inhibiting TNF production, which may act via a novel mechanism. Identification of the target of Y316 may lead to the development of alternative strategies for achieving selective cytokine inhibition.
