Inhibiting NF-κB increases cholesterol efflux from THP-1 derived-foam cells treated with AngⅡ via up-regulating the expression of ATP-binding cassette transporter A1

Objective: To study the role of nuclear factor-kappa B(NF-κB) in cholesterol efflux from THP-1 derived-foam cells treated with AngiotensinⅡ(AngⅡ). Methods:Cultured THP-1 derived-foam cells were treated with AngⅡ or preincubated with tosyl-phenylalanine chloromethyl-ketone(TPCK) NF-κB inhibitor. The levels of activated NF-κB in the cells were examined by sandwich ELISA. Cellular cholesterol content was studied by electron microscopy scanning and zymochemistry via fluorospectrophotometer and cholesterol efflux was detected by scintillation counting technique. ABCA1 mRNA and protein were quantified by RT-PCR and Western blotting. Results:Addition of TPCK to the cells before AngⅡ stimulation attenuated the response of NF-κB p65 nuclear translocation induced by AngⅡ and showed no peak in foam cells group and caused a reduction in cholesterol content and an increase in cholesterol efflux by 24.1%(P < 0.05) and 41.1%(P < 0.05) respectively,when compared with AngⅡgroup. In accordance,the ABCA1 mRNA and protein were increased by 30% and 19%(P < 0.05) respectively,when compared with AngⅡ group. Conclusion:AngⅡ can down-regulate ABCA1 in THP-1 derived-foam cells via NF-κB,which leads to less cholesterol efflux and the increase of cholesterol content with the consequence of the promotion of atherosclerosis.     

Inhibiting NF-κB increases cholesterol efflux from THP-1 derivedfoam cells treated with Angll via up-regulating the expression of ATP-binding cassette transporter A1

Objective:To study the role of nuclear factor-kappa B(NF- K B) in cholesterol efflux from THP-I derived-foam cells treated with Angiotensin Ⅱ (Ang Ⅱ ). Methods:Cultured THP-l derived-foam cells were treated with Ang Ⅱ or preincubated with tosyl-phenylalan inechloromethyl-ketone(TPCK) NF-K B inhibitor. The levels of activated NF-K B in the cells were examined by sandwich ELISA. Cellular cholesterol content was studied by electron microscopy scanning and zymochemistry via fluorospectrophotometer and cholesterol efflux was detected by scintillation counting technique. ABCAI mRNA and protein were quantified by RT-PCR and Western blotting. Results:Addition of TPCK to the cells before Ang Ⅱ stimulation attenuated the response of NF- K B p65 nuclear translocation induced by Ang Ⅱ and showed no peak in foam cells group and caused a reduction in cholesterol content and an increase in cholesterol effiux by 24.1%(P < 0.05) and 41.1%(P < 0.05) respectively, when compared with Ang Ⅱ group. In accordance, the ABCAl mRNA and protein were increased by 30% and 19%(P< 0.05) respectively, when compared with Ang Ⅱ group. Conclusion:Ang Ⅱ can down- regulate ABCAI in THP-l derived-foam cells via NF- K B, which leads to less cholesterol effiux and the increase of cholesterol content with the consequence of the promotion of atherosclerosis.     

High glucose decreases the expression of ATP-binding cassette transporter G1 in human vascular smooth muscle cells

Objective:ATP-binding cassette transporters(ABC)A1 and G1 play an important role in mediating cholesterol efflux and preventing macrophage foam cell formation.In this study,we examined the regulation of ABC transporters by high glucose in human vascular smooth muscle cells(VSMCs),the other precursor of foam cells.Methods:Incubation of human VSMCs with D-glucose(5 to 30 mM)for 1 to 7 days in the presence or absence of antioxidant and nuclear factor(NF)-κB inhibitors,the expressions of ABCA1 and ABCG1 were analyzed by real time PCR and Western blotting.Results:High glucose decreased ABCG1 mRNA and protein expression in cultured VSMCs,whereas the expression of ABCA1 was not significantly decreased.Down-regulation of ABCG1 mRNA expression by high glucose was abolished by antioxidant N-acetyl-L-cysteine(NAC)and NF-κB inhibitors,BAY 11-7085 and tosyl-phenylalanine chloromethyl-ketone(TPCK).Conclusion:High glucose suppresses the expression of ABCG1 in VSMCs,which is the possible mechanism of VSMC derived foam cell transformation.     

Increased expression and activity of MMP-9 in C-reactive protein- induced human THP-1 mononuclear cells is related to activation of nuclear factor kappa-B

The relation between the expression and activity of MMP-9 in C-reactive protein （CRP）-induced human THP-1 mononuclear cells and the activation of nuclear factor kappa-B （NF-κB） was studied to investigate the possible role of CRP in plaque destabilization. Human THP-1 cells were incubated in the presence of CRP at 0 （control group）, 25, 50 and 100 μg/mL （CRP groups） for 24 h. In PDTC （a specific NF-κB inhibitor） group, the cells were pre-treated with PDTC at 10 μmol/L and then with 100 μg/mL CRP. The conditioned media （CM） and human THP-1 cells in different groups were harvested. MMP-9 expression in CM and human THP-1 cells was measured by ELISA and Western blotting. MMP-9 activity was assessed by fluorogenic substrates. The expression of NF-κB inhibitor α （IκB-α） and NF-κB p65 was detected by Western blotting and ELISA respectively. The results showed that CRP increased the expression and activity of MMP-9 in a dose-dependent manner in the human THP-1 cells. Western blotting revealed that IiB-α expression was decreased in the cells with the concentrations of CRP and ELISA demonstrated that NF-κB p65 expression in the CRP-induced cells was increased. After pre-treatment of the cells with PDTC at 10 μmol/L, the decrease in IκB-α expression and the increase in NF-κB p65 expression in the CRP-induced cells were inhibited, and the expression and activity of MMP-9 were lowered too. It is concluded that increased expression and activity of MMP-9 in CRP-induced human THP-1 cells may be associated with activation of NF-κB. Down-regulation of the expression and activity of MMP-9 may be a new treatment alternative for plaque stabilization by inhibiting the NF-κB activation.     

Effects of Oxidized Low Density Lipoprotein on the Expression and Function of ABCA1 in Macrophages

In the present study, we examined the regulation of the expression and function of ABCA1 by modified LDL (ox-LDL) in vitro. After incubation with apoA-I for 24 h, RAW264.7 cells effluxed 37.65 % cholesterol loaded by acetyl LDL (ac-LDL), and 9.78% cholesterol in ox-LDL group. The level of ABCA1 mRNA increased about three times either when cells were incubated with .100 μg/mL ac-LDL or with 100 μg/mL ox-LDL. However, the level of ABCA1 protein rose by 1.57 times in ac-LDL group and 1.26 times in ox-LDL group. These results demonstrated that ox-LDL had different effect on the expression and function of ABCA1, ox-LDL might decrease the cholesterol efflux mediated by ABCA1 through other unknown mechanisms.     

Changes of sulfur dioxide, nuclear factor-κB, and interleukin-8 levels in pediatric acute lymphoblastic leukemia with bacterial inflammation

Background Bacterial inflammation is a common complication in patients with leukemia,and sulfur dioxide （SO2） is a bioactive molecule in modulating Gram-negative bacilli infection.This study aimed to examine the changes in SO2,nuclear factor-κB （NF-κB）,and interleukin-8 （IL-8） levels in pediatric acute lymphoblastic leukemia （ALL） with Gram-negative bacterial inflammation.Methods Fifty-five ALL children were enrolled in this study,including 30 males and 25 females,aged 3-13 years,and the median age was 7.8 years.All these children who accepted chemotherapy for ALL were divided into the control group （before chemotherapy）,the infection group （after chemotherapy with infection）,and the recovery group （the infection was controlled after 1 week）.The serum level of SO2 was detected using high performance liquid chromatography with fluorescence assay,and NF-κB and IL-8 levels were measured by enzyme-linked immunosorbent assay （ELISA）.Human THP-1 cells were cultured,induced,and differentiated into macrophages,which were divided into five groups and each group was cultured with different stimulators：lipopolysaccharide （LPS） group,LPS＋L-aspartate-β-hydroxamate （HDX） group,LPS＋SO2 group,SO2,and control groups.NF-κB level and IL-8 protein contents by ELISA were examined in each group.Results In comparison with those of the control group,levels of serum SO2,NF-κB,and IL-8 of the infection group were significantly increased （P ＜0.05）,while those of the recovery group were significantly decreased （P ＜0.05）.A positive correlation was found between levels of serum SO2 and intracellular NF-κB/IL-8,and the correlation coefficients were 0.671 and 0.798 （P ＜0.05）,respectively.According to the results found in human THP-1 cells,levels of NF-κB and IL-8 in LPS group were significantly increased compared with those of the control group （P ＜0.05）; when compared with those in LPS group,levels of NF-κB in LPS＋HDX group further increased significantly （P ＜     

Expression of NF-κB in hRPE Cells Stimulated by PDTC and IL-1β

The constitutive expression of nuclear-factor-κB (NF-κB) in human pigment epithelial (hRPE) cells cultivated in vitro and the possible changes when incubated with PDTC and IL-I were investigated. The synchronized hRPE cells in vitro were divided into two groups. In nonPDTC group, hRPE cells were exposed respectively to IL-1β and NS (for detecting the constitutive expressions of NF-κB in hRPE cells) ; In PDTC group, PDTC-pretreated hRPE cells were exposed respectively to IL-1β?Aand NS. (for detecting the constitutive expression of NF-κB in PDTC-pretreated hRPE cells). The expression of NF-κB in hRPE cells in two groups was detected by immunofluorescence stain and flow cytometry. The results showed that the constitutive expression of NF-κB in hRPE cells in vitro was 8.05 %, and increased to 30.26 % by IL-1β. After PDTC pretreatment, the constitutive expression of NF-κB in hRPE cells was decreased to 3.74%, and 3.66 % by IL-l,respectively. It was concluded that the expressions of NF-κB in hRPE cells could be increased significantly by IL-1βand depressed effectively by PDTC. Also, PDTC could significantly inhibit the activation of NF-κB induced by IL-1β.     

Role of liver X receptors alpha agonist on expressions of LPS-induced inflammatory response associated factor IRAK-4 and NF-kappaB in Kupffer cells

Objective： To explore the role of activated liver X receptor α （LXRα） on the expressions of interleukin-1 receptor associated kinase-4 （IRAK-4） and NF-kappaB （NF-κB） in the inflammatory response which induced by LPS in the Kupffer cells and to investigate the possible mechanisms of LXRα negative regulation of inflammatory response. Methods： The Kupffer cells were isolated from male Kunming mice by collagen perfusion in situ. And these cells were divided into 4 groups： normal control group, LPS treatment group, LXRct agonist T0901317 treatment group, LPS and T0901317 combined treatment group. The LPS treatment group were treated with a final concentration of 1 μg/ml LPS in RPMI 1640 and cultured for 6 h, the T0901317 treatment group were treated with a final concentration of 5 μg/ml in RPMI 1640 and cultured for 24 h, and the combined treatment group received pre-culture for 24 h with a final concentration of 1μg/ml T0901317 in RPMI 1640 and then cultured for 6 h with a final concentration of 5 μg/ml LPS in RPMI 1640. All groups were cultured for 30 h. The expression of LXRα, IRAK-4 and NF-κB at mRNA and protein levels were detected by real-time PCR and Western blotting, and the TNF-α and IL-1β levels were detected by ELISA. Results： The levels of LXRα mRNA and protein were highest in T0901317 group, and lowest in LPS group （P〈0.05）. The level of IRAK4 and NF-κB mRNAs and proteins were evidently lower in the Combined-treated group than in LPS group （P〈0.05）. And the level of TNF-α and IL-1 were observed highest in LPS group （P〈0.05）, but no difference among the Control group, T0901317 group and Combined-treated group （P〉0.05）. Conclusion： These date suggest that the LXR agonists can effectively up-regulate the expressions of LXRα mRNA and protein and inhibit the inflammatory response. This may be via down-regulating the expressions of IRAK4 and NF-κB at mRNA and protein levels.     

Altered gene expression reveals molecular mechanisms underlying oridonin-induced apoptosis of multiple myeloma LP-1 cells

Objective: To investigate the effect of oridonin on proliferation and invasion of human multiple myeloma LP-1 cells and the underlying mechanism. Methods: LP-1 cells in culture medium in vitro were treated with oridonin at the different concentration. Cell proliferation was measured by Microwave Theory and Techniques (MTT) assay and cell apoptotic rate was detected by flow cytometry. Morphology of cell apoptosis was observed by transmission electron microscope. Expressions of Bax, Bcl-2, Caspase-3, NF-κB as well as I-κB mRNA were detected by real-time PCR. Results: The MTT assays and flow cytometry revealed that oridonin could inhibit the growth of LP-1 cells and cause apoptosis significantly; the suppression was both in time- and dose-dependent manner. Marked morphological changes of cell apoptosis were found under a transmission electron microscope after the cells were treated with oridonin at 25 μmol/L for 24 h. Along with the apoptotic process, Bcl-2, Caspase-3,NF-κB gene expressions were down-regulated (P<0.05). On the contrast, the Bax and I-κB gene expressions were up-regulated (P<0.05). Conclusion: Oridonin could inhibit the proliferation of LP-1 cells via inducing apoptosis. We concluded that oridonin induces apoptosis in LP-1 cells via activation of caspase-3 as well as down-regulation of Bcl-2 and up-regulation of Bax expression. The results suggested that oridonin could induce apoptosis of LP-1 cells through mitochondria- and caspase3-dependent pathways. Meanwhile, the inhibition of NF-κB and the activation of I-κB indicate pro-apoptotic stimuli. In one word, oridonin might be an important potential anti-myeloma reagent.     

Activation of NF-κB in bronchial epithelial cells from children with asthma

Objectives To determine whether nuclear factor-κB (NF-κB) is activated in epithelial cells from children with asthma and to understand the role of NF-κB in airway inflammation in asthma. Methods Bronchial mucosa specimens were obtained from 9 children with asthma and 6 control subjects. NF-κB expression in epithelial cells were detected by immunohistochemical examination, and NF-κB-DNA binding was measured by electrophoretic mobility shift assay (EMSA). Results Nuclear expression of NF-κB in epithelial cells was observed in the 9 asthmatic children. NF-κB-DNA binding was found in 4 asthmatic children (EMSA was performed in 6 asthmatic children). In contrast, both nuclear expression and NF-κB-DNA binding were absent in the 6 control subjects. Conclusion These results indicated that NF-κB is activated in epithelial cells from asthmatic children and the NF-κB activation may be the basis for the increased expression of many inflammatory genes and for airway inflammation in asthma.     

Effect of N-tosyl-L-phenylalanylchloromethyl Ketone on Tumor Necrosis Factor-alpha -induced NF-κB Activation and Apoptosis in U937 Cell Line

Summary: To investigate the effect of N-tosyl-L-phenylalanylchloromethyl ketone (TPCK) on tumor necrosis factor-alpha-induced NF-κB activation and apoptosis in U937 cell line, changes and subcellular localization of NF-κB/p65 and IκB-α were observed by fluorescencemicroscopy and expression and degradation of IκB-α by flow cytometry. The apoptosis of U937 cells was measured by flow cytometry and electrophoresis of DNA. Immunolfluorescence assay showed that NF-κB/p65,IκB-α only localized in cytoplasm. After TNF-α stimulation, p65 was localized only in nuclei, and IκB-α was only localized in cytoplasm and decreased. The changes of TNF-α stimulation were specifically inhibited by TPCK. Flow cytometry also revealed the downregulation of IκB-α protein during TNF-α-induced apoptosis and the down-regulation was specifically inhibited by TPCK. Flow cytometry also showed the apoptosis of U937 cells after TNF-α induction. DNA ladder can be detected in cells treated by TNF-α. It is concluded that degradation of IκB-α protein and NF-κB/p65 translocation occur during TNF-α-induced apoptosis of U937 cells, suggesting the activation of NF-κB.TPCK-sensitive protease plays an important role in the degradation of IκB-α protein induced by TNF-α in U937 cells. TPCK sensitive protease also plays an important role in the apoptosis of U937 cells induced by TNF-α.     

Relationship between Carbachol Hyperstimulation-induced Pancreatic Intracelluar Trypsinogen and NF-κB Activation in Rats in vitro

The relationship between intracelluar trypsinogen activation and NF-κB activation in rat pancreatic acinar cells induced by M3 cholinergic receptor agonist （carbachol） hyperstimulation was studied. Rat pancreatic acinar cells were isolated, cultured and treated with carbachol, the active protease inhibitor （pefabloc） and NF-κB inhibitor （PDTC） in vitro. Intracelluar trypsin activity was measured by using a fluorogenic substrate. The activity of NF-κB was monitored by using electrophoretic mobility shift assay. The results showed that after pretreatment with 2 mmol/L pefabloc, the activities of trypsin and NF-κB in pancreatic acinar cells treated with high concertrations of carbachol （10^-3 mol/L） in vitro was significantly decreased as compared with control group （P〈0.01 ）. The addition of 10^-2 mol/L PDTC resulted in a significant decrease of NF-κB activities in pancreatic acinar cells after treated with high concertrations of carbachol （10^-3 mol/L） in vitro, but the intracelluar trypsinogen activity was not obviously inhibited （P〉0.05）. It was concluded that intracelluar trypsinogen activation is likely involved in the regulation of high concertrations of carbachol-induced NF-κB activation in pancreatic acinar cells in vitro. NF-κB activation is likely not necessary for high concertrations of carbachol-induced trypsinogen activation in pancreatic acinar cells in vitro.     

Triptolide-induced apoptosis by inactivating nuclear factor-kappa B apoptotic pathway in multiple myeloma <Emphasis Type="Italic">in vitro</Emphasis>

The effect of triptolide on proliferation and apoptosis of human multiple myeloma RPMI-8226 cells in vitro,as well as the roles of nuclear factor-kappa B(NF-κB) and IκBα was investigated.The effect of tritptolide on the growth of RPMI-8226 cells was studied by MTT assay.Apoptosis was detected by Hoechest 33258 staining and Annexin V/PI double staining assay.The expression of NF-κB and IκBα was observed by Western blot and confocal microscopy.The results showed that triptolide inactivated NF-κB apoptotic pathway in human multiple myeloma RPMI-8226 cells.Triptolide at nM range induced proliferation inhibition in a dose-and time-dependent manner and apoptosis in a dose-dependent fashion in RPMI-8226 cells.Besides,we observed the inhibition of NF-κB /p65 in the nuclear fraction was correlated with the increase in the protein expression of IκBα in the cytosol.These results suggested that triptolide might exhibit its strong anti-tumor effects via inactivation of NF-κB/p65 and IκBα.     

Effect of Dachengqi Decoction on NF-κB p65 Expression in Lung of Rats with Partial Intestinal Obstruction and the Underlying Mechanism

To investigate the effect of Dachengqi decoction on NF-κB p65 expression in lung of rats with partial intestinal obstruction and the underlying mechanism, 30 SD rats were randomly divided into three groups： sham-operation group, model group and Dachengqi decoction treatment group （Dachengqi group）, with 10 animals in each group. The models were made by partially ligating their large intestines outside the body. The pathological changes were analyzed by HE staining. The expression of NF-κB p65 in rats lung were measured by using real-time polymerase chain reaction and immunohistochemistry respectively. Moreover, the expression of caveolin-1 in rats lung was also measured to. Increased edema, interstitial thickening, hemorrhage, and infiltration of inflammatory cells were found in the model group. In contrast, this change was significantly reduced in Dachengqi group as compared with model group. In addition, the up-regulated caveolin-1 and NF-κB p65 were also suppressed by Dachengqi decoction in lung of rats with partial intestinal obstruction. We are led to concluded that the caveolin-l-NF-κB pathway plays an important role in the development of lung injury of rats with partial intestinal obstruction and Dachengqi decoction could down-regulate the expression of caveolin-1 and NF-κB p65 in lung of rats with partial intestinal obstruction.     

The effect of root of rhododendron on the activation of NF-κB in a chronic glomerulonephritis rat model

Objective:We have explored the role of nuclear factor kappa B(NF-κB) in the pathogenesis of chronic glomerulonephritis,and investigated the effect of rhododendron root on the activation of NF-κB.Methods:Thirty-six Wistar rats were randomly divided into three groups:a control group,a glomerulonephritis model group and a therapy group(glomerulouephritis animals treated with the root of rhododendron).Bovine serum albumin(BSA) nephritis was induced by subcutaneous immunization and daily intraperitoneal administra-tion of BSA.Twenty-four-hour urinary protein and serum creatinine values were measured,and renal pathology was assessed histologi-cally by optical microscopy and electron microscopy.NF-κB activity was determined by an electrophoretic mobility shift assay(EMSA).Results:Compared with the control rats,glomerulonephrids model rats exhibited a significant increase in both 24 h urinary protein and serum creatinine,and had abnormal renal histology.The administration of the root of rhododendron ameliorated these changes.NF-κ B activity in glomerulonephritis model group was greater than that in rhododendron-treated group,and NF-κB activity was greater in both glomerulonephritis groups than in the control group(P<0.01).Conclusion:These observations suggest that NF-κ B plays a role in the pathogenesis of chronic glomerulonephritis,and rhododendron root may attenuate renal damages by downregulating the activation of NF-kB in this model.     

Thymic Stromal Lmphopoietin Pomotes Macrophage-derived Foam Cell Formation简

The effect of thymic stromal lymphopoietin（TSLP） on macrophage-derived foam cell formation and the underlying mechanism were studied. Macrophages isolated from C57BL/6 mice were co-cultured in vitro with different concentrations of TSLP or TSLPR-antibody in the presence of oxidized low density lipoprotein（ox-LDL）. The effects of TSLP on macrophage-derived foam cell formation were observed by using oil red O staining and intracellular lipid determination. The expression levels of foam cell scavenger receptors（CD36 and SRA） as well as ABCA1 and TSLPR were detected by using RT-PCR and Western blotting. As compared with the control group, TSLP treatment significantly promoted lipid accumulation in macrophages, significantly increased protein expression of CD36 and TSLPR in a dose-dependent manner, and significantly reduced the expression of ABCA1 protein in a dose-dependent manner. No significant differences were noted between the TSLPR-antibody group and the control group. TSLP may down-regulate the expression of cholesterol efflux receptor ABCA1 and up-regulate scavenger receptor expression via the TSLPR signaling pathway, thereby promoting macrophage-derived foam cell formation.