Effects of NF-κB "decoy" oligodeoxynucleotides on TNF-α and IL-6 expression in LPS-induced mouse macrophages

AIM: To study the effect of NF-κB "decoy" oligodeoxynucleotides on TNF-α and IL-6 expression in LPS-induced mouse macrophages. METHODS: Mouse macrophage cell line J774.1 cells were cultured with LPS and liposome-mediated oligodeoxynucleotides, and the levels of TNF-α and IL-6 measured in the different culture supernatant by enzyme linked immunosorbent assay. RNA was extracted from macrophages, and the mRNA expression of TNF-α and IL-6 in macrophages was observed by RT-PCR. RESULTS: NF-κB "decoy" oligodeoxynucleotides decreased the expression of TNF-α and IL-6 in LPS-induced macrophages and inhibited generation of TNF-α and IL-6. The level of TNF-α and IL-6 did not change in control group. CONCLUSIONS: NF-κB "decoy" oligodeoxynucleotides inhibit the expression of TNF-α and IL-6 in LPS-induced macrophages, which is probably due to the specific inhibition of activated NF-κB binding sites .     

Role of TLR4-TRPC6 in LPS-induced NF-κB P65 expression and nuclear translocation in airway epithelial 16HBE cells

AIM: To investigate the role of Toll-like receptor 4 (TLR4) and transient receptor potential channel 6 (TRPC6) signaling pathway in lipopolysaccharide (LPS)-induced nuclear factor-κB (NF-κB) P65 expression and nuclear translocation in airway epithelial cells (16HBE) for supplementing the mechanism for airway inflammation. METHODS: After stimulating the 16HBE cells with LPS at 1 mg/L for 0, 0.5, 2, 6, 12 and 24 h, the expression of NF-κB P65 at mRNA and protein levels in the 16HBE cells were determined by RT-PCR and Western blot respectively, and the nuclear translocation of NF-κB P65 was detected by immunocytochemical staining method. The effects of TLR4 inhibitor CLI-095 at 5 μmol/L and TRPC6 agonist Hyp9 at 10 μmol/L on LPS (1 mg/L)-induced NF-κB P65 expression and nuclear translocation in the 16HBE cells were determined by RT-PCR, Western blot and immunocytochemical staining. RESULTS: LPS increased the mRNA and protein expression of NF-κB P65 and nuclear translocation in the 16HBE cells(P<0.05). TLR4 inhibitor CLI-095 reduced the mRNA and protein expression of NF-κB P65 and nuclear translocation induced by LPS, while Hyp9 enhanced the mRNA and protein expression of NF-κB P65 and nuclear translocation induced by LPS in the 16HBE cells(P<0.05). CONCLUSION: LPS induces the expression and nuclear translocation of NF-κB P65 in the 16HBE cells via TLR4-TRPC6 signaling pathway.     

Effects of eicosapentaenoic acid on expression of nuclear factor κB and release of cytokines in human umbilical vein endothelial cells stimulated by lipopolysaccharide

AIM: To investigate the effects of eicosapentaenoic acid(EPA) on the expression of nuclear factor kappa B(NF-κB) and release of vascular endothelial growth factor(VEGF), IL-1α and IL-6 in cultured human umbilical vein endothelial cells(HUVECs) stimulated by lipopolysaccharide(LPS).METHODS: HUVECs were obtained from cell strain and cultured in vitro. HUVECs were divided into 4 groups: control group, LPS group, 0.030 g/L EPA treatment group and 0.050 g/L EPA treatment group. The cells were cultured with LPS alone in LPS group and incubated with EPA for 1 h in the EPA pretreatment groups at the concentrations of 0.030 g/L and 0.050 g/L before LPS stimulation. Twenty-four hours after stimulated by LPS, the protein expression of NF-κB p65 in HUVECs were assessed by Western blotting analysis at different time points. The production of VEGF, IL-1α and IL-6 in cultured HUVECs was evaluated by ELISA. The effects of EPA on the protein expression of NF-κB p65 and the production of VEGF, IL-1α and IL-6 in HUVECs challenged by LPS were also determined.RESULTS: Compared with control group, the protein expression of NF-κB p65 was significantly increased in HUVECs induced by LPS and was inhibited by EPA. Compared with control group, the protein expression of VEGF, IL-1α and IL-6 was dramatically increased in HUVECs induced by LPS and most of the increase was inhibited by EPA.CONCLUSION: LPS enhances the protein expression of NF-κB and the release of VEGF, IL-1α and IL-6. EPA inhibits the protein expression of NF-κB, and the production of VEGF and the inflammatory cytokines in cultured HUVECs stimulated by LPS, indicating that EPA may be useful for preventing and treating neovascular and inflammatory diseases.     

Effect of NOD8 on production of nitric oxide,IL-1β and TNF-α in LPS-treated macrophages

AIM: To investigate the effect of NOD8 on lipopolysaccharide (LPS)-induced releases of nitric oxide (NO), tumor necrosis factor α (TNF-α) and interleukin-1β (IL-1β) in RAW264.7 cells. METHODS: The plasmids of pEGFP-C2 and pEGFP-NOD8 were transfected into RAW264.7 cells respectively. The transfected and non-transfected cells were stimulated by LPS for 0, 6, 12 and 24 h. NO production was evaluated by Griess reagent assay, and the levels of IL-1β and TNF-α were measured by ELISA. The protein expression of NOD8 and the nuclear translocation of nuclear factor κB (NF-κB) p65 subunit were detected by Western blotting. The level of activated caspase-1 was determined by fluorimetric method. RESULTS: Compared with pEGFP-C2 group, the protein expression of NOD8 was significantly elevated in pEGFP-NOD8+LPS group. The releases of NO, IL-1β and TNF-α were obviously increased after RAW264.7 cells were treated with LPS for 6 h, 12 h and 24 h, and while the secretion of NO was significantly reduced in the cells transfected with pEGFP-NOD8 and induced by LPS for 12 h and 24 h, and the release of IL-1β was also significantly reduced at 6 h, 12 h and 24 h. However, no significant difference of TNF-α release was observed between pEGFP-C2+LPS group and pEGFP-NOD8+LPS group. The activation of caspase-1 in RAW264.7 cells stimulated with LPS for 6 h, 12 h and 24 h was markedly increased, and the expression of NF-κB p65 subunit in the cytoplasm was significantly decreased, indicating that p65 nuclear translocation was increased. In addition, the activation of caspase-1 and the nuclear translocation of p65 were significantly inhibited in pEGFP-NOD8+LPS group. CONCLUSION: NOD8 suppresses the releases of LPS-induced NO and IL-1β in RAW264.7 cells by inhibiting the activation of caspase-1 and NF-κB.     

Effects of diterpenoid C from ether extract of Radix Curcumae on nuclear factor-κB activity in LPS-induced human gastric adenocarcinoma SGC7901 cells

AIM: To observe the effects of diterpenoid C from ether extract of Radix Curcumae (RC) on the activity of nuclear factor-κB in human gastric adenocarcinoma SGC7901 cells stimulated with lipopolysaccharide (LPS). METHODS: SGC7901 cells were normally cultured, induced by LPS, or treated with LPS plus RC. The protein expression of IKKα, IKKβ, p65, phosphorylated p65 and phosphorylated IκBα was assayed by Western blotting. NF-κB DNA binding activity was determined by electrophoretic mobility shift assay. RESULTS: RC reduced the protein expression of IKKα, IKKβ, p65, phosphorylated p65 and phosphorylated IκBα induced by LPS. NF-κB DNA binding activity increased much greatly by LPS stimulation, while RC resisted the action of LPS. CONCLUSION: RC may attenuate the secretion of inflammatory cytokines by inhibiting the activation of NF-κB signaling pathway.     

Effect of recombinant rat CC16 protein on LPS-induced expression of TNF-α, IL-6 and IL-8 in rat tracheal epithelial cells

AIM: To explore the effect of recombinamt rat CC16 protein (rCC16) on LPS-induced expression of tumor necrosis factor-alpha (TNF-α), interleukin-6 (IL-6) and IL-8 in the rat tracheal epithelial (RTE) cells.METHODS: The RTE cells were incubated with rCC16 at concentrations of 0.5, 1.0 and 2.0 mg/L in serum-free media for 2 h prior to LPS (0.1 mg/L) treatment for further 24 h. The cells were harvested for assessing the mRNA levels of TNF-α, IL-6 and IL-8 by RT-qPCR. The cell culture supernatants were collected for analyzing the protein levels of TNF-α, IL-6 and IL-8 by ELISA. In addition, the nuclear translocation of nuclear factor-κB (NF-κB) p65 was tested by Western blot.RESULTS: rCC16 inhibited LPS-induced IL-6 and IL-8 expression at both mRNA and protein levels in the RTE cells in a concentration-dependent (0~2 mg/L) manner, as demonstrated by RT-qPCR and ELISA. However, no concentration-dependent manner between the dose of rCC16 and TNF-α expression was observed, and rCC16 inhibited LPS-induced TNF-α expression at lower concentration (0.5 mg/L). rCC16 concentration-dependently inhibited the effects of LPS on the level of nuclear translocation of NF-κB p65.CONCLUSION: rCC16 suppresses LPS-mediated TNF-α, IL-6 and IL-8 production through inactivation of NF-κB activity in RTE cells.[KEY WORDS] CC16 protein; Airway inflammation; LPS; Inflammatory mediators; Nuclear factor-κB     

Inhibitory effect of madecassoside on LPS-stimulated microglia

AIM: To observe the inhibitory effect of madecassoside on the LPS-stimulated microglia and to investigate its possible mechanism. METHODS: Microglia cells of neonatal Sprague-Dawley (SD) rats were cultured, isolated and purified. Microglia cells were activated with lipopolysaccharide (LPS). The inhibitory effect of madecassoside on microglia was measured by MTT assay. Tumor necrosis factor alpha (TNF-α), interleukin 1β (IL-1β) were detected by ELISA. Cell cycle and apoptotic rate were evaluated by flow cytometry. The expression of TLR4 was detected by Western blotting. The expression of NF-κB was detected by RT-PCR. RESULTS: LPS induced the proliferation of microglia and release inflammatory cytokines significantly. Compared with LPS group, madecassoside inhibited the proliferation of microglia induced by LPS in a dose dependent manner. The IC₅₀ value of madecassoside was 10.97 nmol/L to microglia after incubation for 48 h. Madecassoside also decreased the levels of TNF-α and IL-6, increased the ratios of microglia at the G₂ phase and the apoptotic rate, decreased the expression of TLR4 and NF-κB significantly (P<0.05). CONCLUSION: Madecassoside has inhibitory effects on the proliferation of LPS-stimulated microglia, by which the mechanism may be related to inhibition of the expression of TLR4 and NF-κB, change of cell cycle distribution and induction of microglia apoptosis.     

Inhibitory effect of proanthocyanidins B1 and B2 on inflammation of BV-2 cells induced by lipopolysaccharide

AIM: To investigate the different inhibitory effects of proanthocyanidins B1 and B2, which are isomers, on the inflammatory response of BV-2 cells induced by lipopolysaccharide (LPS). METHODS: MTT assay was used to detect the effects of proanthocyanidins B1 and B2 on the viability of BV-2 cells. LPS (1 mg/L) was used to promote BV-2 cells to secrete inflammatory factors. ELISA, chemotaxis assay and Western blot were used to detect the influence of proanthocyanidins B1 and B2 on the levels of tumor necrosis factor-α (TNF-α), interleukin-1β (IL-1β), cell chemotaxis and phosphorylation of NF-κB. RESULTS: Proanthocyanidins B1 and B2 did not show cytotoxicity effect on BV-2 cells. Proanthocyanidin B1 and B2 inhibited the cell chemotaxis, phosphorylation of NF-κB, and releases of TNF-α and IL-1β. CONCLUSION: Proanthocyanidins B1 and B2 inhibit the inflammatory response of BV-2 cells induced by LPS, and their action intensity didn't show significant difference.     

Resveratrol attenuates inflammatory pain induced by complete Freund's adjuvant via NF-κB signaling pathway in a mouse model

AIM: To investigate the anti-inflammatory action of resveratrol (Res) and its correlation with nuclear factor-κB (NF-κB) signaling pathway in a mouse model of inflammatory pain.METHODS: BALB/c mice (n=60) were randomly divided into 6 groups:normal control group, inflammatory pain model group, positive control (dexamethasone, 0.5 mg/kg) group and resveratrol (100, 50 and 25 mg/kg) groups (10 mice in each group). In order to observe the anti-inflammatory pain effects of reseratrol on mice, the paw withdrawal mechanical threshold, paw withdrawal thermal latency and cold withdrawal times were detected. In order to analyze the mechanism of analgesic effect of resveratrol, the expression levels of NF-κB, inhibitor of NF-κB (IκB) α, inhibitor of NF-κB kinase (IKK) β, tumor necrosis factor (TNF)-α and interleukin (IL)-1β in the spinal cord tissues (L4~L6) of the mice were determined by RT-PCR and Western blot.RESULTS: The resveratrol at 100 and 50 mg/kg increased the paw withdrawal mechanical threshold, prolonged the paw withdrawal thermal latency, and decreased the cold withdrawal times in the inflammatory pain mice (P<0.05 or P<0.01). The resveratrol at 100 mg/kg down-regulated the mRNA and protein expression levels of NF-κB, IκBα, IKKβ, TNF-α and IL-1β in the spinal cord tissues (L4~L6) of inflammatory pain mice (P<0.05 or P<0.01).CONCLUSION: Resveratrol ameliorates the inflammatory pain of the mice induced by complete Freund's adjuvant. The mechanism is related to the inhibition of NF-κB signaling pathway.     

Effect of MIF antisense oligonucleotides on expression of MIF in macrophages

AIM: To investigate the effect of antisense oligonucleotides on expression of macrophage migration inhibitory factor (MIF) in macrophages. METHODS: MIF phosphorothioate oligonucleotides was designed and synthesized. The phosphorothioate antisense, sense and missense oligonucleotides of mouse MIF was transfected into macrophages, separately. After that, macrophages were incubated with LPS. Cell culture medium was collected for MIF protein detection by EIA. Cellular RNA was extracted and the expression of MIF mRNA was examined by RT-PCR analysis. RESULTS: LPS stimulation resulted in a specific time-dependent expression of MIF derived from macrophages. MIF mRNA and MIF protein level increased at 6 h and reached a plateau at 9-12 h after LPS stimulation. The macrophages treated with antisense oligonucleotides showed a significant decrease in MIF mRNA and MIF protein after LPS stimulation than those with LPS stimulation only and LPS plus sense or missense oligonucleotides (P<0.05). CONCLUSION: Antisense oligonucleotides of MIF inhibit the expression of MIF mRNA and MIF protein in macrophages treated with LPS.     

AHV-PI attenuates endothelial cell injury induced by LPS

AIM:To investigate the effect of platelet inhibitor from Agkistrodon halys venom (AHV-PI) on lipopolysaccharide (LPS) induced human umbilical vein endothelial cells (HUVECs) injury in vitro, and to explore its mechanism. METHODS:Cultured HUVECs were induced inflammatory injury by LPS (1 mg/L). The experiment was divided into blank control group, LPS group, AHV-PI group and AHV-PI+LPS group. The viability of HUVECs was measured by MTT assay. The morphological changes of HUVECs were observed under inverted microscope. The optimum concentration of AHV-PI at 5 mg/L was selected. Flow cytometry was used to detect apoptosis of HUVECs. Immunohistochemical method was used to observe the expression of tissue type plasminogen activator (t-PA) and plasminogen activator indhibitor-1 (PAI-1) of HUVECs. ELISA was used to detect the concentrations of intercellular adhesion molecule-1 (ICAM-1) and tissue factor (TF) in the supernatant. The activation and translocation of NF-κB subunit p65 were observed by immunofluorescence staining. RESULTS:The HUVECs were spindle shaped, the ratio of length to width was increased, the cells were fibroblast-like, and granular substance appeared in the cytoplasm in LPS group. The viability and morphological changes of HUVECs were not significantly affected as treated with AHV-PI at concentration of 0~5 mg/L, but the viability of HUVECs induced by LPS was inhibited and the morphological changes were alleviated. Compared with the blank control group, the levels of TF and ICAM-1 in the supernatant increased, and the expression of t-PA and PAI-1 in the HUVECs was decreased in LPS group. Compared with the LPS group, the contents of TF and ICAM-1 in the supernatant were significantly decreased, the expression of t-PA and PAI-1 in the HUVECs was increased and the expression of nucleus NF-κB p65 was decreased in AHV-PI+LPS group (P<0.05). CONCLUSION:AHV-PI reduces HUVECs damage. The protective mechanism is related to the inhibition of cytokine secretion and NF-κB activation.     

Effect of microRNA-132 transfection on lipopolysaccharide-induced inflammation in rat alveolar macrophages

AIM: To investigate the effect of microRNA-132 (miR-132) transfection on the lipopolysaccharide (LPS)-induced inflammation in rat alveolar macrophages. METHODS: The rat alveolar macrophage NR8383 cultured without pyrogen in vitrowere divided into blank control group, negative control group and transfected group. The cells in the 3 groups were transfected with phosphate buffer solution (PBS), Lipofectamine 2000 and synthesized miR-132 mimic respectively. The cell proliferation was detected by Cell Counting Kit-8 (CCK-8) assay. Real-time PCR was used to detect the expression of miR-132 in the cells. After NR8383 cells were stimulated with LPS for 6 h, the NF-κB DNA-binding activity was measured by electrophoretic mobility shift assay (EMSA). The expression of tumor necrosis factor-α (TNF-α) and interleukin-6 (IL-6) in NR8383 cells was assayed by Western blotting.RESULTS: After transfection, the expression of miR-132 was significantly higher than that in blank control group and negative control group. The growth of NR8383 cells in transfected group was significantly inhibited compared with blank control group and negative control group (P<0.05). After the cells were stimulated with LPS, the productions of NF-κB, TNF-α and IL-6 in transfected NR8383 cells were decreased compared with blank control group and negative control group (P<0.05).CONCLUSION: Transfection of alveolar macrophages with miR-132 significantly suppresses the cell growth, and inhibits inflammatory responses induced by LPS.     

LPS-induced hyperpermeability in brain vascular endothelial cell is related to NF-κB signaling

AIM: To investigate the role of nuclear factor kappa B (NF-κB) signaling in the changes of permeability in brain-derived microvascular endothelial (bEnd.3) cells induced by lipopolysaccharide (LPS).METHODS: The bEnd.3 cells were randomly divided into 3 groups: bEnd.3 group, bEnd.3/vector group and bEnd.3/muIκBα group. The cells in the latter 2 groups were transfected with pcDNA3.1hygro and DNMu-IκBα (a dominant-negative mutant of IκB) plasmids, respectively. All the cells were exposed to LPS. The activity of NF-κB, monolayer barrier integrity and F-actin distribution were detected by luciferase reporter assay, transendothelial electrical resistance (TEER) assay and rhodamine-phalloidin staining, respectively. The expression of tight junction proteins (ZO-1 and claudin-5) and phosphorylation of myosin light chain (MLC) were determined using Western blotting.RESULTS: In bEnd.3 group and bEnd.3/vector group, the NF-κB activity began to increase obviously as early as 0.5 h after pretreatment with LPS. LPS decreased TEER, and induced F-actin rearrangement and ZO-1 down-regulation in 3 h. Incubation of the cells with LPS for 12 h induced the most significant disruptive effects on the permeability and tight junctions. Moreover, high expression of phosphorylated MLC accompanied with the early damages of tight junctions was observed. However, these destabilizing alterations were suppressed in bEnd.3/muIκBα group by the inhibition of NF-κB activity.CONCLUSION: LPS induces hyperpermeability in brain microvascular endothelial cells. The functions of NF-κB signaling are related to influencing disruptions of tight junctions by regulating the phosphorylation of MLC.