The expression of NF-κB and ICAM-1 in rat brain of experimental intracerebral hemorrhage and cerebral microvascular endothelial cells injured by hydrogen peroxide

AIM: To discuss the possible mechanism of the inflammation after intracerebral hemorrhage (ICH) and the relationship of nuclear factor-kappa B (NF-κB) and intercellular adhesion molecule-1 (ICAM-1). METHODS: The expression of NF-κB and ICAM-1 were detected by immunohistochemistry, in situ hybridization, immunocytochemistry and Western blotting techniques in rat brain of experimental ICH and cerebral microvascular endothelial cells (RCMECs) injured by hydrogen peroxide. RESULTS: The expression of NF-κB p65 and ICAM-1 were up-regulated in rat brain after ICH. The ICAM-1 reached the peak at 1 day while the NF-κB at 4th day. NF-κB p65 expressed remarkably in cultured RCMECs immediately after injured by hydrogen peroxide, while ICAM-1 expressed remarkably　2 hours later. PDTC, an inhibitor of NF-κB, down-regulated the expression of NF-κB and ICAM-1. CONCLUSION: NF-κB induces the expression of ICAM-1 in RCMECs injured by reactive oxygen species (ROS).     

uclear factor κB in LPS stimulated rat alveolar macrophages promotes TNF-α secretion

AIM: To investigate the activation of nuclear factor κB (NF-κB) induced by lipopolysaccharides (LPS) in rat alveolar macrophages (AMs) and its regulatory role in tumor necrosis factor (TNF-α) secretion. METHODS: The dynamic activity changes of NF-κB induced by LPS were determined with electrophoretic mobility shift assay (EMSA). Antisense oligonucleotides of NF-κB subunit (p65) were transfected into AMs prior to LPS stimulation. The effect of antisense oligonucleotide transfection on expressions of p65 and TNF-α in supernatant were measured with Western blotting and enzyme linked immunosorbent assay (ELISA), respectively.RESULTS: NF-κB activity increased markedly and reached its peak level at 4 h after LPS stimulation. After transfected with antisense oligonucleotides of NF-κB subunit (p65), expression of p65 and TNF-α in supernatant decreased markedly.CONCLUSION: NF-κB activity has a positive effect on regulating secretion of TNF-α in AMs induced by LPS.     

SC58125 regulates TNF-α induced apoptosis in human colonic carcinoma cell line HT29 by inhibiting IκBα degrades

AIM:To investigate whether SC58125 synergizes with TNF-α to induce HT-29 cell apoptosis and study the possible molecular mechanism. METHODS:By using MTT,Hoechst 33342 staining and agarose gel electrophoresis,the effect of SC58125/TNF-α on the proliferation and apoptosis of HT-29 cell line was examined. The activity of caspase-3,the expression of IκBα,the phosphorylation level of IκBα,and the activation of NF-κB were measured after treatment with SC58125 by electrophoretic mobility shift assay and Western blotting.RESULTS:Both SC58125 and TNF-α exhibited cytotoxicity. The combination of the two reagents significantly reduced HT-29 cell viability in a dose-dependent manner. SC58125 and TNF-α co-treated cells showed induced nuclear condensation and fragmentation,and led to oligonucleosomal cleavage of genomic DNA,which was accompanied by the induction of caspase activity. IκBα levels were substantially decreased by the treatment of TNF-α. The degradation of IκBα was almost completely inhibited when SC58125 was added. NF-κB was activated in HT-29 cells after treatment with TNF-α,whereas pretreatment of HT-29 cells with SC58125 for 2 h,TNF-α induced NF-κB DNA binding was profoundly suppressed. CONCLUSION:SC58125 synergizes with TNF-α to inhibit cell growth and induces apoptosis in HT-29 cells,which may be mediated by activating caspase-3 and preventing degradation of IκBα.     

RIP1-mediated necroptosis regulates inflammatory response of renal tubular epithelial cells via NF-κB signaling pathway

AIM To investigate the effect of receptor-interacting protein 1 (RIP1)-mediated necroptosis on human kidney proximal tubular cell inflammation and its related mechanisms. METHODS Human kidney proximal tubular HK-2 cells were cultured in vitro, and stimulated with tumot tumor necrosis factor-α (TNF-α) and Z-VAD-FMK for 24 h. Lactate dehydrogenase (LDH) cytotoxicity assay was used to detect the percentage of necrosis. Western blot was used to detect the protein expression of RIP1, IKK-α and NF-κB p65. The protein levels of interleukin-1β (IL-1β) and monocyte chemoattractant protein-1 (MCP-1) were determined by Western blot and ELISA. Real-time PCR was used to detect the mRNA expression level of NF-κB p65. Furthermore, the RIP1 inhibitor necrostatin-1 (Nec-1) and the NF-κB specific inhibitor ammonium pyrrolidinedithiocarbamate (PDTC) were used, and the above indicators were also detected. RESULTS Compared with control group, the protein level of RIP1 was increased in TNF-α combined with Z-VAD-FMK stimulation group (T/Z group). The protein levels of IKK-α and NF-κB p65 were obviously increased, and the release of LDH was increased (P<0.01). Western blot and ELISA showed that the expression levels of IL-1β and MCP-1 were significantly increased (P<0.01). Real-time PCR showed that the mRNA expression level of NF-κB p65 was also obviously increased. After Nec-1 or PDTC stimulation (T/Z+N group or T/Z+P group), the release of LDH, and the expression levels of inflammation-related indicators IL-1β and MCP-1 were significantly decreased. The protein expression levels of IL-1β and MCP-1 were further reduced after treatment with the above 2 stimulati (T/Z+P/N group). CONCLUSION Under T/Z condition, RIP1-mediated necroptosis plays an important role in renal tubular inflammatory response, which may be partly achieved by regulating the activation of NF-κB signaling pathway.     

1-O-acetylbritannilactone inhibits vascular inflammatory response through suppressing NF-κB activation

AIM: To investigate the effects and molecular mechanism of 1-O-acetylbritannilatone (ABL) on LPS-induced inflammatory responses in aorta in vitro.METHODS: The aorta loops pretreated with ABL were stimulated with LPS for different times. The protein extracts from the aorta were used to detect the expression of inflammatory factors by Western blotting. RESULTS: ABL inhibited the activation of NF-κB and the expression of inflammatory factors iNOS, COX-2, ICAM-1 and VCAM-1, and increased the level of anti-inflammatory factor IκBα via blocking the phosphorylation activation of IKK and the degradation of IκBα induced by LPS. CONCLUSION: ABL abolishes the vascular inflammatory response to LPS stimulation through modulating NF-κB activity.     

NF-κB activation in keloid fibroblasts stimulated with TNF-α

AIM: To investigate NF-κB p65 activation and IκB-α expression in keloid fibroblasts (KFB) and normal skin fibroblasts (NSF) stimulated with TNF-α and to explore the underlying molecular pathogenesis of keloid formation. METHODS: Primary KFB was cultured. The location of NF-κB p65 and IκB-α in KFB and NSF at quiescent condition and the nuclear translocation of NF-κB p65 after TNF-α stimulation were observed by immunofluorescence technique. NF-κB p65 DNA binding activity was detected with TransAMTM NF-κB p65 kit. The IκB-α protein level was determined by means of Western blotting technique. RESULTS: After stimulated with TNF-α, NF-κB p65 translocated into the nucleus. NF-κB p65 DNA binding activity increased to its maximum at 1 h and was dropped to normal at 4 h. TNF-α induced most degradation of IκB-α at 15 min and became detectable in cytoplasm after 4 h. KFB showed more sensitive ability to TNF-α stimulation than NSF. CONCLUSION: NF-κB may play a role in keloid pathogenesis.     

Construction and identification of recombinant adenovirus vector carrying a N-terminal phosphorylation sites-deleted human IκBα mutant gene

AIM:To optimize the IκBα mutant (IκBαM) gene derived from human placenta tissue by deleting N-terminal phosphorylation sites of serine 32/36,and to construct and identify its replication-deficient recombinant adenovirus (AdIκBαM).METHODS:The IκBαM gene (203-1 003 bp) was acquired by positional cloning,followed by subcloning it into pShuttle and pGEM-T vectors for further PCR,double digestion,DNA sequencing and homology analysis.Subsequently,the expression unit of pShuttle-IκBαM containing CMV promoter,IκBαM cDNA and poly A signals was inserted into Ad5 vector,after which the resultant recombinant adenovirus AdIκBαM was packaged in 293 cells by cotransfection with lipofectamine.Western blotting analysis and electrophoretic mobility shift assay were utilized to detect the AdIκBαM-mediated expression of IκBαM gene in 293 cells and its suppressive effect on phorbol myristate acetate (PMA)-induced nuclear factor κB (NF-κB) activation in ECV304 cells,respectively.RESULTS:The relevant nucleotide and amino acid sequence of IκBαM gene was consistent with that of GenBank (accession number M69043).The titer of the prepared AdIκBαM was 4.0×1012 pfu/L.Moreover,the IκBαM gene was expressed in 293 cells,and potently inhibited the PMA-induced NF-κB activation in ECV304 cells in a dose-dependent manner.CONCLUSION:AdIκBαM is a nonvel vector for both efficient transfer and expression of IκBαM gene as well as specific inhibition of NF-κB activity,providing a promising future for gene therapy of asthma.     

Effect of CCK-8 on signal mechanisms of IL-12 secretion in LPS-induced mice

AIM:To study the effects of CCK-8 on IL-12 secretion in LPS-induced mice and to investigate the signal transduction mechanisms involving NF-κB and p38 MAPK. METHODS:Female BALB/c mice were induced by LPS in the presence or absence of CCK-8, CCK-A or B receptor antagonist. The productions of IL-12p40 and p70 in the sera, lung and spleen tissues were evaluated by ELISA. Changes of pIκB, p-p38 protein expression and the NF-κB/DNA binding activity were examined by Western blotting and EMSA, respectively. RESULTS:CCK-8 increased the expressions of IL-12p40, p70 in the serum, lung and spleen tissues of LPS-induced mice, inhibited IκB phosphorylation and NF-κB/DNA binding activity, increased p38 phosphorylation. CONCLUSION:CCK-8 increases the production of IL-12 in LPS-induced mice probably via activating p38 MAPK. NF-κB might not mediate the activating effect of CCK-8 on IL-12 production.     

Inhibitory effect of HET0016 on LPS-induced proliferation and migration of microglia

AIM To study the effects of HET0016 on the proliferation and migration of microglia stimulated by lipopolysaccharide (LPS). METHODS Primary microglia from neonatal SD rats were isolated, purified and cultured. CCK-8 assay was performed to detect the effect of HET0016 on the viability of microglia after treatment with LPS. The levels of 20-hydroxyeicosatetraenoic acid （20-HETE）, tumor necrosis factor-α (TNF-α) and interleukin-1β (IL-1β) were measured by ELISA. The proportion of S phase was evaluated by flow cytometry. The cell migration ability was detected by Transwell assay and scratch wound healing assay. The protein expression of NF-κB p50 and p65 was determined by Western blot. RESULTS LPS induced the increases in the proliferation and migration of microglia and the release of inflammatory cytokines (P<0.05). Compared with LPS group, HET0016 inhibited the cell proliferation and migration (P<0.05), decreased the levels of TNF-α and IL-1β (P<0.05), and reduced the expression of NF-κB p50 and p65 (P<0.05). CONCLUSION HET0016 has inhibitory effects on the proliferation and migration of microglia induced by LPS, and reduces the release of inflammatory cytokines. The mechanism may be related to NF-κB signaling pathway.     

Effects of antioxidant and NF-κB on the induction of IL-8 in human colon cancer cell line HT-29 cells in vitro

AIM: To investigate the role of nuclear factor κB (NF-κB) in the induction of IL-8 gene by TNF-α in colon cancer cells and the effect of antioxidant on the induction of IL-8. METHODS: ELISA was used to detect the concentrations of IL-8. IL-8 mRNA was analyzed by using RT-PCR. NF-κB in the cell nuclei was detected with electrophoretic mobility shift assay. RESULTS: (1) IL-8 production and IL-8 mRNA expression induced by TNF-α was blocked by pyrrolidine dithiocarbamate (PDTC). (2) TNF-α triggered the activation and translocation of NF-κB and PDTC inhibited the activation of NF-κB induced by TNF-α. CONCLUSION: The induction of IL-8 gene and protein by TNF-α is dependent on the activation of NF-κB. Antioxidants may inhibit the induction of IL-8 gene and protein through inhibiting NF-κB activation.     

Effect of TNF-α on production and activation of caspase-3 in primary rat renal proximal tubule cells

AIM: To investigate the production and activation of caspase-3 in primary rat renal proximal tubule cells in response to tumor necrosis factor-α(TNF-α) and the implication of nuclear factor-κB (NF-κB) in the process. METHODS: Isolated rat renal proximal tubule cells (PTCs) from male adult Sprague Dawley rats were treated with TNF-α according to the indicated time courses. A specific NF-κB inhibitor, Bay11-7082, was used alone or as a pretreatment for 1 h followed by exposure to TNF-α for 24 h. The protein levels of cleaved caspase-3, caspase-3, I-κBα, phosphorylated I-κBα, and GAPDH were detected by Western blotting using specific antibodies. RESULTS: The protein level of cleaved caspase-3 relative to caspase-3 was significantly increased in the presence of TNF-α for 6 h, 12 h, and 24 h. Protein levels of caspase-3 were significantly decreased by 12 h and returned to baseline by 24 h in the presence of TNF-α. Treatment with Bay11-7082 for 25 h alone or pretreatment with Bay11-7082 for 1 h followed by addition of TNF-α for 24 h caused a remarkable reduction in both cleaved caspase-3 and caspase-3 as compared to control and TNF-α treated groups. An increase in phosphorylated I-κBα was observed from 15 min to 60 min after treatment with TNF-α at a dose of 10 μg/L in PTCs. CONCLUSION: NF-κB is not only associated with the activation of caspase-3 but also the production of caspase-3 in primary rat renal proximal tubule cells in response to TNF-α.     

Effects of simvastatin on proliferation of esophageal cancer cells through NF-κB p65 pathway

AIM To investigate the effects of simvastatin （SIM） on the proliferation of esophageal cancer Eca109 cells through NF-κB p65 pathway. METHODS Esophageal cancer Eca109 cells were cultured in vitro and treated with SIM at different concentrations （2 , 4, 8, 16 and 32 μmol/L）. The proliferation of Eca109 cells was measured by MTT assay and plate colony formation assay. The proliferation-related protein levels of cyclin D1, c-Myc, NF-κB p65 （p65） and IκB-α in the esophageal cancer Eca109 cells were determined by Western blot. ELISA was used to detect the levels of tumor necrosis factor α （TNF-α） and interleukin-6 （IL-6） in the culture supernatant of Eca109 cells. RESULTS Compared with control group, the inhibitory effects of SIM at 2 , 4 , 8 and 16 μmol/L on the viability of Eca109 cells were increased in a concentration-dependent and time-dependent manners （P<0.05）. Simultaneously, the inhibitory rates of SIM at 16 and 32 μmol/L on the viability of Eca109 cells showed no significant difference （P>0.05）. The inhibitory rates of SIM at 16 μmol/L on the viability of esophageal cancer cells was 50.61% at 48 h, which was closed to half of the inhibitory dose IC₅₀, and it was used as the optimum concentration and time for follow-up experiments. Compared with control group, the plate colony formation rate of Eca109 cells, the protein levels of cyclinD1, c-Myc, nuclear p65, TNF-α and IL-6 in 8 and 16 μmol/L groups were decreased, while the levels of cytosolic p65 and IκB-α proteins were increased （P<0.05）. No significant difference of plate colony formation rate in Eca109 cells, and the protein levels of cyclin D1, c-Myc, nuclear and cytoplasmic p65, IκB-α, TNF-α and IL-6 between 16 μmol/L SIM group and 32 μmol/L SIM group was observed （P>0.05）. CONCLUSION Simvastatin inhibits the proliferation of esophageal cancer Eca109 cells, and its mechanism may be related to up-regulation of IκB-α, down-regulation of cyclinD1 and c-myc, inhibition of p65 nuclear translocation, and the expression of TNF-α and IL-6 downstream of NF-κB p65 pathway.     

Caspase 3 inhibitor Ac-DEVD-CHO attenuates 10-hydroxycamptothecin-induced activation of NF-κB in Bcap37 cells

AIM:To investigate the role of caspase 3 inhibitor Ac-DEVD-CHO in caspase 3 signaling pathway and NF-κB activation induced by 10-hydroxycamptothecin (HCPT) in human breast carcinoma cells. METHODS:The cell growth inhibition was measured by MTT assay. Agarose gel electrophoresis was performed for detecting cell apoptosis. Western blotting was used for determining protein expression. DIG-EMSA was conducted to measure the DNA-binding activation of NF-κB. RESULTS:Caspase 3 inhibitor Ac-DEVD-CHO attenuated HCPT-induced apoptosis in human breast carcinoma. Ac-DEVD-CHO also suppressed the degradation of caspase 3 and IκBα,and arrested the activation of NF-κB. CONCLUSION:Caspase 3 inhibitor Ac-DEVD-CHO regulates the activation of caspase 3 and NF-κB,and attenuates apoptosis in Bcap37 cell line induced by HCPT.