Objective To investigate whether P12，a kind of lipopolysaccharide（LPS）-binding protein（LBP） inhibitory peptide，could suppress the binding of LPS to alveolar macrophages（AMs） in a mouse model of endotoxemia in vivo.Methods Forty mice were randomly divided into five groups，ie.a control group，an endotoxemia group，a low dose P12-treated group，a middle dose P12-treated group and a high dose P12-treated group.Mouse model of endotoxemia was established by LPS injection intraperitoneally in the endotoxemia group and P12-treated groups.P12 was instilled via the tail vein.The effects of P12 on the binding of LPS to AMs were determined by flow cytometric analysis and quantization by mean fluorescence intensity(MFI).The productions of tumor necrosis factor α(TNF-α) in serum of mice were measured by enzyme-linked immunosorbent assay(ELISA).Results MFI in AMs from low，middle and high dose P12-treated groups was 40.08%，30.76% and 24.45%，respectively，which was higher than that of the control group(4.61%)，but less than that of the endotoxemic mice(45.31%).The concentration of TNF-α in serum of low，media and high dose P12-treated mice was (112.69±19.78)pg/mL，(86.34±9.25) pg/mL，(70.48±8.48)pg/mL respectively，which was higher than that of the control group[(24.88±5.82)pg/mL]，but less than that of the endotoxemic mice[(180.17±39.14)pg/mL].Conclusion The results suggest that P12 inhibit the binding of LPS and AMs，thus reduce the proudction of TNF-α stimulated by LPS.
Objective To investigate the influence of lipopolysaccharide(LPS) on the proliferation and collagen synthesis of normal human skin fibroblasts so as to elucidate its relation with skin wound healing. Methods Fibroblasts wereisolated and cultured in vitro, and then exposed to different doses of LPS(0.005, 0.010, 0.050, 0.100, 0.500, and 1.000 μg/ml) from E.coli055∶B5 respectively. Then the absorbance (A) value of fibroblasts was determined with the colorirneteric thiazolylblue (MTT) assay, and the cell number was counted under inverted phase contrast microscope from the 1st day to the 9th day after LPS administration, and collagen synthesis of fibroblasts in culture medium was measured with the method of pepsin digestion after incorporation of 3Hproline into stable, single-layered, confluent fibroblasts at 7 days after LPS administration. Results Compared with control group, A value increased with the increasing concentration of LPS (0.005 μg/ml 0.500 μg/ml) and LPS of 0.100 μg/mlgroup had the best effect. The difference was remarkable from the 5th day to the 9th day(P＜0.05). A value decreased when challenged with the LPS of 1.000 μg/ml and the difference was remarkable from the 3rd day to the 9th day(P＜0.05). Cell number increased with theadministration of LPS of different concentrations (0.005 μg/ml 0.500 μg/ml) and LPS of 0.100 μg/mlgroup had the best effect. The difference was remarkable from the 1st day to the 6th day(P＜0.05). Cell number decreased remarkably when challenged with LPS of 1.000 μg/ml and the difference was remarkable from the 2nd day to the 9th day(P＜0.05). Collagen synthesis increased when challenged with LPS of different concentrations (0.005 μg/ml 0.500 μg/ml) and the 0.100 μg/ml group had the best effect. However, when the dose of LPS reached 1.000 μg/ml, it inhibited collagensynthesis. Conclusion LPS could promote the proliferation andcollagen synthesis of fibroblasts within a certain range of low doses, but over-high dose ofLPS might inhibit the proliferation and collagen synthesis of fibroblasts, suggesting that LPS of certain concentrations might contribute to wound healing, while excessive LPS has negative effect on wound healing.
Objective To investigate the effects of inhaled prostaglandin E1 （PGE1）on Th1/Th2 polarity in rat model of lipopolysaccharide（LPS） induced acute lung injury（ALI）.Methods Healthy adult male Wistar rats [weight （200±20）g] were randomly divided into normal control（NS） group，LPS group and PGE1 group.The model of ALI were established by injecting LPS of 5 mg/kg into caudal vein.The rats in PGE1 group inhaled aerosolized PGE1（2 μg/mL）for 30 minutes after LPS injection,then repeat the procedure 12 hours later. 1 h，6 h，12 h and 24 h after last PGE1 inhalation,enzyme linked immunosorbant assay （ELISA） was empolyed to measure the level of interferon-γ（IFN-γ）and interleukin-4（IL-4）in the serum and bronchoalveolar lavage fluid（BALF）and the ratio of IFN-γ/IL-4（Th1/Th2）was calculated.Pathological examination was made under light microscope.Results Pathological examination of lung tissue demonstrated success ALI model.Compared to NS group,the ratio of IFN-γ/IL-4（Th1/Th2）both in serum and BALF in LPS group elevated significantly（Plt;0.01）. PGE1 administration significantly decreased the ratio IFN-γ/IL-4 in serum after 6h（Plt;0.01）and in BALF at all time points（Plt;0.01）.Conclusion The imbalance of was found in the LPS induced ALI，inhaled PGE1 aerosol inhalation could restore Th1/Th2 cytokine balance in the rats model induced by LPS.
Objective To investigate the transduction pathway of TREM-1 during endotoxininduced acute lung injury ( ALI) in mice through the specific activating or blocking TREM-1.Methods 40 mice were randomly divided into a saline control group, an ALI group, an antibody group, and a LP17 group ( 3.5 mg/kg) . All mice except the control group were intraperitoneally injected with lipopolysaccharide ( LPS) to establish mouse model of ALI. Two hours after LPS injection, anti-TREM-1mAb ( 250 μg/kg) was intraperitoneally injected in the antibody group to activation TREM-1, and synthetic peptide LP17 was injected via tail vein in the LP17 group to blocking TREM-1. After 6,12,24, 48 hours, 3 mice in each group were sacrificed for sampling. The expression of NF-κB in lung tissue was determined by immunohistochemistry. The levels of TNF-α, IL-10, TREM-1, and soluble TREM-1 ( sTREM-1) in lung tissue and serumwere measured by ELISA. Pathology changes of lung were observed under light microscope, and Smith’s score of pathology was compared. Results Administration of anti-TREM-1mAb after ALI modeling significantly increased the NF-κB expression in lung tissue at 48h, resulting in a large number of pro-inflammatory cytokines releasing in the lung tissue and serumand lung pathology Smith score increasing. Administration of LP17 after modeling significantly down-regulated the expressions of NF-κB and pro-inflammatory cytokines, while led to a slight increase of anti-inflammatory cytokines and a decline of lung pathology Smith’s score.Conclusion TREM-1 may involve in inflammatory response by promoting the generation of inflammatory factors via NF-κB pathway, thus lead to lung pathological changes in ALI.
ObjectiveTo investigate whether the miR-33s negatively regulates LPS-induced production of inflammatory cytokines by targeting p38 MAPK. MethodsHuman monocytes THP-1 cells were cultured in vitro and transfected with miR-33s mimic (25 nmol/L) or miR-33s inhibitor (25 nmol/L)by TransIT-X2® Dynamic Delivery System for 24 h. Then the transfected THP-1 cells were stimulated by LPS of 10.0 ng/mL for 24 h. The expression of miR-33s and p38 MAPK protein were measured by semi-quantitative RT-PCR. The concentrations of TNF-α,IL-6 and IL-1β in the cultured supernatant were assessed by ELISA. ResultsThe transfection of miR-33s mimic significantly increased the release of TNF-α,IL-6 and IL-1β(P<0.05). The expression of p38 MAPK protein was also significantly reduced(P<0.05). However,the pre-treatment of miR-33s inhibitor reversed the LPS-induced release of TNF-α,IL-6,and IL-1β,and the expression of p38 MAPK protein of THP-1 cells. ConclusionmiR-33s may play an important role in the regulation in inflammatory factors released from THP-1 cells by targeting p38 MAPK.
Objective To detect the effects of cytokines on the expression of early growth response gene-1 (Egr-1) in cultured human retinal pigment epithelial (RPE) cells. Methods Immunofluorescence staining, Western blotting and reverse transcription polymerase chain reaction (RT-PCR) were used to detect and quantitatively analyze the expression of Egr-1 protein and mRNA in cultured human RPE cells which were exposed to stimulants, including 20 mu;g/ml lipopolysaccharide (LPS), 40 ng/ml tumor necrosis factor (TNF)-alpha;, 10 U/ml interferon (IFN)gamma;, 30% supernatant of monocyte/macrophage strain (THP1 cells) and the vitreous humor from healthy human eyeballs, for 0, 10, 20, 30, 40 and 60 minutes, respectively. Results The RPE cells stimulated for 0 minute revealed faint green fluorescence of Egr-1 in the cytoplasm. With exposure to the stimulants, the expressionof Egr-1 increased obviously and b green fluorescence was found in cytoplasm in some nuclei of RPE cells. Compared with the untreated RPE cells, after stimulated by 20 mu;g/ml LPS, 40 ng/ml TNFalpha;, 10 U/ml IFNgamma;, 30% supernatant of THP-1 cells and the vitreous humor, the approximate ultimate amplitudes of Egr-1 mRNA enhanced 1.9, 1.3, 14, 1.2, and 1.4 times, respectively; the greatest amplitudes of Egr-1 protein increased 3.4, 1.2, 1.7, 32, and 1.3 times, respectively. Conclusion LPS, TNF-alpha;, IFN-gamma;, supernatant of THP-1 cells and the vitreous humor can upregulate the expression of Egr-1 mRNA and protein in cultured human RPE cells, and induce its nuclear transposition, which suggests the activation of Egr-1.
ObjectiveTo evaluate the combination of lipopolysaccharide-amine nanopolymersomes (LNPs), as a gene vector, with target gene and the transfection in bone marrow mesenchymal stem cells (BMSCs) so as to provide a preliminary experiment basis for combination treatment of bone defect with gene therapy mediated by LNPs and stem cells. MethodsPlasmid of bone morphogenetic protein 2 (pBMP-2)-loaded LNPs (pLNPs) were prepared. The binding ability of pLNPs to pBMP-2 was evaluated by a gel retardation experiment with different ratios of nitrogen to phosphorus elements (N/P). The morphology of pLNPs (N/P=60) was observed under transmission electron microscope (TEM) and atomic force microscope (AFM). The size and Zeta potential were measured by dynamic light scattering (DLS). The resistance of pLNPs against DNase I degradation over time was explored. The viability of BMSCs, transfection efficiency, and expression of target protein were investigated after transfection by pLNPs in vitro. ResultsAt N/P≥1.5, pLNPs could completely retard pBMP-2; at N/P of 60, pLNPs was uniform vesicular shape under AFM; TEM observation demonstrated that pLNPs were spherical nano-vesicles with the diameter of (72.07±11.03) nm, DLS observation showed that the size of pLNPs was (123±6) nm and Zeta potential was 20 mV; pLNPs could completely resist DNase I degradation within 4 hours, and such protection capacity to pBMP-2 decreased slightly at 6 hours. The cell survival rate first increased and then decreased with the increase of N/P, and reached the maximum value at N/P of 45; the cytotoxicity was in grade I at N/P≤90, which meant no toxicity for in vivo experiment. While the transfection efficiency of pLNPs increased with the increase of N/P, and reached the maximum value at N/P of 60. So it is comprehensively determined that the best N/P was 60. At 4 days, transfected BMSCs expressed BMP-2 continuously at a relatively high level at N/P of 60. ConclusionLNPs can compress pBMP-2 effectively to form the nanovesicles complex, which protects the target gene against enzymolysis. LNPs has higher transfection efficiency and produces more amount of protein than polyethylenimine 25k and Lipofectamine 2000.
Objective To investigate the mRNA and protein expression of human β-defensin-2 (hBD-2) induced by lipopolysaccharide (LPS)，IL-1β and TNF-α in human airway primary epitheliums.Methods The bronchial primary epitheliums from human were stimulated with LPS，IL-1β and TNF-α respectively and then were harvested for hBD-2 expression detection.The mRNA expression of hBD-2 was detected by RT-PCR，and the protein expression by immunocytochemistry and western blot.Results There was a small expression of hBD-2 mRNA in human airway primary epitheliums before stimulation.The hBD-2 mRNA expression was significantly increased after 3 hours of LPS，IL-1β and TNF-α stimulation respectively and the expression increasement was in a dose dependent manner.The hBD-2 protein could be detected in cytoplasm after 4 hours of LPS (0.1 μg/mL)，IL-1β (1 ng/mL) and TNF-α (10 ng/mL) stimulation.Conclusions LPS and proinflammatory cytokines can induce the mRNA and protein expression of hBD-2 in a short time.The expression of hBD-2 may play an initial defense role against bacterial invasion.
ObjectiveTo investigate the mechanism of lung tissue apoptosis in LPS-induced mice ARDS via TNF-α neutralization. MethodsThirty-six mice were randomly divided into a control group,a LPS group,and TNF-α neutralization group.LPS(5 mg/kg) was intratracheally nebulized to induce ARDS in the LPS group and the TNF-α neutralization group.Twenty-four hours before LPS treatment,etanercept (0.4 mg/kg) was abdominal injected to the mice in the TNF-α neutralization group.Mice were sacrificed 2 hours after LPS treatment.PCR were used to detected the expression of NF-κB p65,Bax and Bcl-2 in lung tissue.Western blot were used to detected protein level of NF-κB p65,Erk1/2 and their phosphorylation and Bax,Bcl-2.The lung dry-to-wet ratio was measured.The lung histological changes were evaluated by HE staining. ResultsActivation level of NF-κB p65 and Erk1/2 was elevated,the ratio of Bcl-2 and Bax was decreased in the LPS group(P<0.05).After TNF-α neutralization,the activation level of NF-κB p65 and Erk1/2 were reduced,the ratio of Bcl-2 and Bax was increased (P<0.05).Compared with the LPS group,the lung dry-to-wet ratio and lung injury semi-quantitative score were significantly decreased in the TNF-α neutralization group (P<0.05). ConclusionTNF-α neutralization can suppress lung injury in LPS-induced ARDS mice by inhibiting activation of NF-κB p65 and Erk1/2,increasing the ratio of Bcl-2 and Bax ratio,and eventually reducing apoptosis.
ObjectiveTo investigate the effect of curcumin on lipopolysaccharide (LPS)-induced inflammation and apoptosis in alveolar macrophage via microRNA-132 (miR-132)/high mobility group protein B1 (HMGB1).MethodsThe cultured mouse alveolar macrophage line (RAW264.7 cells) were divided into the control group, the LPS group, the LPS+50 μmol/L curcumin group, and the LPS+100 μmol/L curcumin group. Forty-eight hours after drug treatment, the levels of miR-132/HMGB1, inflammatory mediator and apoptotic were detected. Secondly, the empty vector, synthetic miR-132 mimics and inhibitors were transfected into another cultured mouse alveolar macrophage line (RAW264.7 cells) to detect the inflammation and apoptosis of alveolar macrophage after transfection.ResultsCompared with the control group, in the LPS group, the apoptosis of alveolar macrophage, the levels of interleukin (IL)-6, IL-8 and tumor necrosis factor (TNF)-α, and the expression of miR-132 increased, while the expression of HMGB1 decreased (P<0.05); compared with the LPS group, in the two curcumin groups, the apoptosis of alveolar macrophage, the levels of IL-6, IL-8 and TNF-α, and the expression of miR-132 decreased, while the expression of HMGB1 increased (P<0.05); and the greater the drug concentration, the more obvious the effect (P<0.05). In addition, up-regulation of miR-132 reduced the expression of HMGB1 in alveolar macrophage, increased inflammatory factor, and induced apoptosis in alveolar macrophage; however, down-regulation of miR-132 increased the expression of HMGB1 in alveolar macrophage, reduced inflammatory factor, and inhibited apoptosis in alveolar macrophage (P<0.05).ConclusionCurcumin could decrease LPS-induced inflammation and apoptosis in alveolar macrophage via decreasing miR-132 and increasing HMGB1.