Objective: To evaluate the therapeutic efficacy of injecting recombinant mutant human tumor necrosis factor (rmhTNF) into pericardial cavity of carcinoma patients with malignant pericardial effusion. Methods: In 20 ca...Objective: To evaluate the therapeutic efficacy of injecting recombinant mutant human tumor necrosis factor (rmhTNF) into pericardial cavity of carcinoma patients with malignant pericardial effusion. Methods: In 20 cases of malignant pericardial effusion, the intrapericardial catheter was inserted into pericardial cavity, and then rmhTNF of 1.5 × 107 U was infused. The infusion was repeated every 5-7 days with the total 4-6 times. If the effusion disappeared, rmhTNF was then used 2 more times and then the intrapericardial catheter was pulled out. Results: Of 20 patients, 14 were complete response (CR), 4 were partial response (PR) and 2 no change (NC). The disappearance of effusion in 6 cases lasted for more than 6 months. Conclusion: Injecting rmhTNF into pericardial cavity may be a better way to control malignant pericardial effusion and has mild side effects.展开更多
Aim: To investigate the effect of inhibition of telomerase with human telomerase reverse transcriptase (hTERT) antisense on tumor necrosis factor-α (TNF-α-induced apoptosis in prostate cancer cells (PC3). Meth...Aim: To investigate the effect of inhibition of telomerase with human telomerase reverse transcriptase (hTERT) antisense on tumor necrosis factor-α (TNF-α-induced apoptosis in prostate cancer cells (PC3). Methods: Antisense phosphorothioate oligodeoxynucleotide (AS PS-ODN) was synthesized and purified. Telomerase activity was measured using the telomeric repeat amplification protocol (TRAP) and polymerase chain reaction enzyme-linked immunoassay (PCR-ELISA). hTERT mRNA was measured by reverse transcription PCR (RT-PCR) assay and gel-image system, hTERT protein was detected by immunochemistry and flow cytometry. Cell viability was detected by 3-(4, 5-dimethylthiazol-2-yl)-2,5-Diphenyltetrazolium (MTT) assay. Cell apoptosis was observed by morphological method and determined by flow cytometry. Results: The telomerase activity decreased with time after hTERT AS PS-ODN treatment. The levels of hTERT mRNA decreased with time after hTERT AS PS-ODN treatment, which appeared before the decline of the telomerase activity. The percentage of positive cells of hTERT protein declined with time after hTERT AS PS-ODN treatment, which appeared after the decline of hTERT mRNA. There was no difference in telomerase activity, hTERT mRNA and protein levels between hTERT sense phosphorothioate oligodeoxynucleotide (S PS-ODN) and the control group. The cell viability decreased with time after hTERT AS PS-ODN combined with TNF-α treatment. The percentage of apoptosis increased with time after hTERT AS PS-ODN combined with TNF-α treatment. There was no difference in cell viability and the percentage of apoptosis between hTERT S PS-ODN and the control group. Conclusion: hTERT AS PS-ODN can significantly inhibit telomerase activity by downregulating the hTERT mRNA and protein expression, and inhibition of telomerase with hTERT antisense can enhance TNF-α- induced apoptosis of PC3 cells.展开更多
BACKGROUND: Previous studies have reported that statins are less toxic to the human body and have greater antitumor activity; however, few studies have addressed the antitumor effect of statins combined with tumor ne...BACKGROUND: Previous studies have reported that statins are less toxic to the human body and have greater antitumor activity; however, few studies have addressed the antitumor effect of statins combined with tumor necrosis factor-related apoptosis inducing ligand (TRAIL). OBJECTIVE: To explore the effect of TRAIL combined with mevastatin on the proliferation and apoptotic cell death of a human glioma cell line SWO-38, and to study its mechanism of action. DESIGN, TIME AND SETTING: An in vitro control experiment was performed at the Central Laboratory of the Third Hospital Affiliated to Sun Yat-sen University, between January and April 2009. MATERIALS: The human SWO-38 cell line was provided by Cell Research, Department of Animal Experimental Center of Sun Yat-sen University; human recombinant soluble TRAIL by R&D, USA; and mevastatin by Sigma, USA. METHODS: SWO-38 cells were separately incubated in TRAIL (100, 200, 300, 400, and 500 tJg/L) and mevastatin (5, 10, 20, 30, and 40 pmol/L) for 72 hours. In addition, SWO-38 cells were incubated in TRAIL (300 μg/L), mevastatin (30 μmol/L), and a solution containing both TRAIL and mevastatin for 12, 24, 48 and 72 hours. MAIN OUTCOME MEASURES: Cell proliferation was detected using methyl thiazolyl tetrazolium assay; cell apoptosis was observed using Hoechst 33258 staining and fluorescence microscopy and was measured using Annexin V/propidium iodide flow cytometry; TRAIL R1/DR4 and TRAIL R2/DR5 protein expressions levels were measured using indirect immunofluorescence staining combined with flow cytometry in the recombinant soluble TRAIL (rsTRAIL, 300 tJg/L), mevastatin (30 IJmol/L) and combination groups; TRAIL R1/DR4 and TRAIL R2/DR5 mRNA expression was detected using real-time polymerase chain reaction. RESULTS: rsTRAIL, mevastatin and their combination inhibited tumor proliferation in a time- and dose-dependent manner. The proliferation inhibitory rate and apoptosis rate of human SWO-38 cells in the combined group were significantly greater than the rsTRAIL or mevastatin alone group (P 〈 0.01). TRAIL R1/DR4 and TRAIL R2/DR5 protein and mRNA expressions were increased in the combination group compared with mevastatin or rsTRAIL alone after 72 hours (P 〈 0.01). CONCLUSION: Both rsTRAIL and mevastatin inhibit the proliferation and apoptosis of the human glioma cell line SWO-38, while their combination enhances the anti-tumor effect. The mechanism of action possibly correlates to the upregulation of TRAIL R1/DR4 and TRAIL R2/DR5 mRNA expression by mevastatin, thereby enhancing the cell sensitivity to rsTRAIL.展开更多
BACKGROUND: Studies of several animal models of central nervous system diseases have shown that neural progenitor cells (NPCs) can migrate to injured tissues. Stromal cell-derived factor 1 alpha (SDF-la), and its...BACKGROUND: Studies of several animal models of central nervous system diseases have shown that neural progenitor cells (NPCs) can migrate to injured tissues. Stromal cell-derived factor 1 alpha (SDF-la), and its primary physiological receptor CXCR4, have been shown to contribute to this process. OBJECTIVE: To investigate migration efficacy of human NPCs toward a SDF-1α gradient, and the regulatory roles of tumor necrosis factor-α (TNF-α) and interleukin-8 (IL-8) in SDF-1α/CXCR4 axis-induced migration of NPCs. DESIGN, TIME AND SETTING: An in vitro, randomized, controlled, cellular and molecular biology study was performed at the Laboratory of Department of Cell Biology, Medical College of Soochow University between October 2005 and November 2007. MATERIALS: SDF-1α and mouse anti-human CXCR4 fusion antibody were purchased from R&D Systems, USA. TNF-αwas purchased from Biomyx Technology, USA and IL-8 was kindly provided by the Biotechnology Research Institute of Soochow University. METHODS: NPCs isolated from forebrain tissue of 9 to 10-week-old human fetuses were cultured in vitro. The cells were incubated with 0, 20, and 40 ng/mL TNF-α, or 0, 20, and 40 ng/mL IL-8, for 48 hours prior to migration assay. For antibody-blocking experiments, cells were further pretreated with 0, 20, and 40 μg/mL mouse anti-human CXCR4 fusion antibody for 2 hours. Subsequently, the transwell assay and CXCR4 blockade experiments were performed to evaluate migration of human NPCs toward a SDF-1α gradient. Serum-free culture medium without SDF-1α served as the negative control. MAIN OUTCOME MEASURES: The transwell assay was performed to evaluate migration of human NPCs toward a SDF-1α gradient, which was blocked by fusion antibody against CXCR4. In addition, CXCR4 expression in human NPCs stimulated by TNF-α and IL-8 was measured by flow cytometry. RESULTS: Results from the transwell assay demonstrated that SDF-1α was a strong chemoattractant for human NPCs (P 〈 0.01), and 20 ng/mL produced the highest levels of migration. Anti-human CXCR4 fusion antibody significantly blocked the chemotactic effect (P 〈 0.05). Flow cytometry results showed that treatment with TNF-α and IL-8 resulted in increased CXCR4 expression and greater chemotaxis efficiency of NPCs towards SDF-1α(P 〈 0.01). CONCLUSION: These results demonstrated that SDF-la significantly attracted NPCs in vitro, and neutralizing anti-CXCR4 antibody could block part of this chemotactic function. TNF-α and IL-8 increased chemotaxis efficiency of NPCs towards the SDF-1αgradient by upregulating CXCR4 expression in NPCs.展开更多
BACKGROUND Cartilage tissue engineering is a promising strategy for treating cartilage damage.Matrix formation by adipose-derived stem cells(ADSCs),which are one type of seed cell used for cartilage tissue engineering...BACKGROUND Cartilage tissue engineering is a promising strategy for treating cartilage damage.Matrix formation by adipose-derived stem cells(ADSCs),which are one type of seed cell used for cartilage tissue engineering,decreases in the late stage of induced chondrogenic differentiation in vitro,which seriously limits research on ADSCs and their application.AIM To improve the chondrogenic differentiation efficiency of ADSCs in vitro,and optimize the existing chondrogenic induction protocol.METHODS Tumor necrosis factor-alpha(TNF-α)inhibitor was added to chondrogenic culture medium,and then Western blotting,enzyme linked immunosorbent assay,immunofluorescence and toluidine blue staining were used to detect the cartilage matrix secretion and the expression of key proteins of nuclear factor kappa-B(NF-κB)signaling pathway.RESULTS In this study,we found that the levels of TNF-αand matrix metalloproteinase 3 were increased during the chondrogenic differentiation of ADSCs.TNF-αthen bound to its receptor and activated the NF-κB pathway,leading to a decrease in cartilage matrix synthesis and secretion.Blocking TNF-αwith its inhibitors etanercept(1μg/mL)or infliximab(10μg/mL)significantly restored matrix formation.CONCLUSION Therefore,this study developed a combination of ADSC therapy and targeted anti-inflammatory drugs to optimize the chondrogenesis of ADSCs,and this approach could be very beneficial for translating ADSC-based approaches to treat cartilage damage.展开更多
BACKGROUND: Human tumor necrosis factor-like molecule 1A (hTL1A) is a strong T helper cell type 1 (Thl) co-stimulator. Guillain-Barre syndrome (GBS) is an autoimmune disorder of the nervous system, which is med...BACKGROUND: Human tumor necrosis factor-like molecule 1A (hTL1A) is a strong T helper cell type 1 (Thl) co-stimulator. Guillain-Barre syndrome (GBS) is an autoimmune disorder of the nervous system, which is mediated by Thl cells. OBJECTIVE: To determine hTL1A expression in peripheral blood T lymphocytes of acute GBS children and the effects of hTL1A on secretion of interferon-γ. DESIGN, TIME AND SETTING: A randomized, controlled, neuroimmunological in vitro study was performed at the Central Laboratory of First Hospital of Jilin University, China from November 2005 to November 2007. MATERIALS: Venous blood samples were obtained from 6 healthy donors, aged 6-12 years (all routine blood examination items were normal), and 6 additional children with acute GBS, aged 6-12 years. The GBS children fell ill within 1 week and were not treated with hormones or immunoglobulin Purified recombinant human soluble tumor necrosis factor-like molecule 1A (rhsTL1A, 1 mg/mL, relative molecular mass 22 000, 6× His tag, soluble form) was supplied by the Central Laboratory of First Hospital of Jilin University, China. METHODS: Peripheral blood mononuclear cells were isolated from healthy donors using the standard Ficoll gradient centrifugation and were incubated in 96-well culture plates. The cells were assigned to the following groups: control (2 μg/mL phytohemagglutinin), 2μg/mL phytohemagglutinin + 25, 100 and 400 ng/mL rhsTL1A. T cell proliferation was quantified using the tritiated thymidine (3H-TdR) method. Serum interferon-γ levels in acute GBS children were detected by enzyme-linked immunosorbent assay (ELISA). The ratio of hTL1A-positive T cells to CD3-positive T cells in peripheral blood of acute GBS children was determined using flow cytometry. Following in vitro pre-activation of peripheral blood mononuclear cells by 2 μg/mL phytohemagglutinin, the peripheral blood mononuclear cells were treated with 400 ng/mL exogenous rhsTLIA. Finally, peripheral blood mononuclear cell-secreted interferon-γlevels were measured by ELISA. MAIN OUTCOME MEASURES: The following parameters were measured: rhsTLIA stimulation index to stimulate proliferation of T cells; the serum interferon-γ levels in acute GBS children; the ratio of hTL1A-positive cells to CD3-positive cells; the levels of interferon-γ secreted by peripheral blood mononuclear cells in acute GBS children, as well as rhsTL1A-stimulated interferon-γ levels. RESULTS: T cell proliferation assay revealed that the stimulation index in each rhsTL1A group was greater than the control group. The stimulation index of the 400 ng/mL rhsTL1A group was the greatest. Serum interferon-γ levels in acute GBS children were significantly greater than the control group (P 〈 0.05). The ratio of hTLIA+ CD3+ T cells to CD3+ T cells in acute GBS children was significantly greater than the control group (P 〈 0.01 ). Phytohemagglutinin stimulated peripheral blood mononuclear cells to a greater extent than 400 ng/mL rhsTL1A in the acute GBS group, and the secreted interferon-γ levels were significantly increased (P 〈 0.05). CONCLUSION: In T cells pre-activated with 2 μg/mL phytohemagglutinin, proliferation was effectively increased with 400 ng/mL rhsTL1A treatment. Expression of hTLIA was increased in activated T cells from peripheral blood of acute GBS children, followed by increased interferon-γ secretion. These mechanisms are considered to be part of the pathological process that induces the secretion of inflammatory cytokines in GBS syndrome.展开更多
Acute myocardial infarction (AMI) is an acute cardiovascular emergency. This study was undertaken to assess the effect of tumor necrosis factor-a (TNF-a) on ventricular arrhythmias induced byAMI in rats in vivo. ...Acute myocardial infarction (AMI) is an acute cardiovascular emergency. This study was undertaken to assess the effect of tumor necrosis factor-a (TNF-a) on ventricular arrhythmias induced byAMI in rats in vivo. Two hundred and forty male Wistar rats were randomized into a sham- operation group, an AMI group, and a recombinant human tumor necrosis factor receptor:Fc fusion protein(rhTNFR:Fc) group. Acute anterior wall myocardial infarction was produced in the AMI group by ligating the left anterior descending coronary artery (LAD), and there was no ligation but operation in the sham-operation group. The rhTNFR:Fc group was treated with rhTNFR:Fc(10 mg/kg), a TNF-a antagonist, 24 hours before LAD ligation. The spontaneous and induced programmed electrical stimulation ventricular arrhythmias were recorded at baseline and 10 minutes, 20 minutes, 30 minutes, 60 minutes, 3 hours, 6 hours and 12 hours after ligation. At the same time the protein and mRNA expression levels of TNF-a among different groups were detected by histochemistry and real-time fluorescent quantitative PCR. Expression of TNF-a increased markedly from 10 minutes after infarction, peaked at 20-30 minutes, and returned to baseline gradually in the AMI group and rhTNFR:Fc group. The time- windows of spontaneous and induced ventricular arrhythmias were similar. Compared with the AMI group, the rhTNFR:Fc group showed a lesser expression of TNF-a protein and a lower incidence of ventricular arrhythmias (P〈0.05). There was no obvious change in the sham-operation group. The expression of TNF-a induced by AMI could contribute to the onset of ventricular arrhythmias.展开更多
BACKGROUND: Previous studies of curcumin have focused mainly on its cytotoxic properties for antitumor therapy. There are few studies addressing the application of curcumin in the prevention and treatment of nervous ...BACKGROUND: Previous studies of curcumin have focused mainly on its cytotoxic properties for antitumor therapy. There are few studies addressing the application of curcumin in the prevention and treatment of nervous system diseases. OBJECTIVE: To observe the protective effect of curcumin against tumor necrosis factor-alpha (TNF-α)-induced neuronal damage in the rat hippocampus and to explore the intervention effect of curcumin on Ca^2+ influx following neuronal damage. DESIGN, TIME AND SETTING: A cell morphological and physiological study was performed at the Institute of Brain Research, Medical College of Jinan University, China, from December 2006 to June 2007. MATERIALS: Curcumin (Sigma, USA) and TNF-α (Sigma, USA) were used in this study. METHODS: Hippocampal neurons were isolated from one-day neonatal rats and primarily cultured for 5 days. Following this they received 1 pmol/L curcumin and 100 ng/mL TNF-a pre-treatment. Dynamic morphological changes were observed for 1 hour by inverted microscopy. At 48 hours post-treatment, static morphological characteristics of the neurons were observed using inverted microscopy. Subsequently, hippocampal neurons were primarily cultured for 7 days, after receiving 1 pmol/L curcumJn and 4.5 ng/mL TNF-a pre-treatment. Intracellular free Ca^2+ was measured using Fluo 3/acetoxymethyl ester. MAIN OUTCOME MEASURES: Effects of curcumin on TNF-a-induced neuronal damage and Ca^2+ influx in the rat hippocampus were measured. RESULTS: Following curcumin treatment, TNF-a-induced neurons grew as normal. TNF-a induced a rapid Ca^2+ influx into the neuronal cytoplasm; however, Ca2+ fluorescence intensity only slightly increased when neurons were co-perfused with curcumin and TNF-α. CONCLUSION: Curcumin has a protective effect on rat hippocampal neurons possibly by reducing the TNF-α-induced rapid Ca^2+ influx into neuronal cytoplasm and by maintaining the Ca^2+ homeostasis.展开更多
Using light microscopy and electron microscopy, we observed the morphological changes inheuman hepatocellular carcinoma cell line (SMMC-7721) treated with tumor necrosis tumor necrosis factor (TNF)and the cytocidal ef...Using light microscopy and electron microscopy, we observed the morphological changes inheuman hepatocellular carcinoma cell line (SMMC-7721) treated with tumor necrosis tumor necrosis factor (TNF)and the cytocidal effect of TNF on the heterotransplanted human hepatocellular carcinoma. It wasfound that the changes of the injury occurred earlier in the cell membranes than in the nuclei duringthe course of TNF killing of SMMC-7721 cells and there were similar lesions around the necroticarea in the heterotransplanted human hepatocellular carcinoma in the nude mice as compared withthose produced in SMMC-7721 cells. In addition, the determination of the DNA content in TNF-treated SMMC-7721 cells and controls revealed no significant difference between them. On the basisof these results and Darzynkiewicz’s proposals, it is suggested that TNF exerts its tumor-selectivekilling effect by binding to a specific to a specific plasma membrane receptor to disturb synthesis or assembly ofcell membrane components, thus causing the plasma membrane injury and finally cell lysis.展开更多
AIM: Epidermal growth factor (EGF) plays an important role in the regulation of gastrointestinal tissue growth and development, and it can stimulate epithelial proliferation, cell differentiation and growth. It has be...AIM: Epidermal growth factor (EGF) plays an important role in the regulation of gastrointestinal tissue growth and development, and it can stimulate epithelial proliferation, cell differentiation and growth. It has been established that the EGF can promote gastric cytoprotection and ulcer healing. But the potential ability of EGF to regulate the gastric cancer growth is unknown. This study is to investigate the influence of EGF on human gastric cancer cell and the implanted tumor growth of nude mice. METHODS: The cell growth rates of human gastric adenocarcinoma cell lines MKN-28, MKN-45, SGC-7901 and normal human gastric epithelial cells 3T3 were assessed when incubated with recombinant human EGF (rhEGF, 0.05, 0.1, 0.5, 1.0, 10, 50, 100 mg.L(-1)) using MTT method. The cells of MKN-28, MKN-45, SGC-7901 (gastric cancer tissue 1.5mm(3)) were implanted in the BALB/cA nude mice for 10 days.The EGF was given intraperitoneally (15, 30, 60 microg.kg(-1)) for 3 weeks. The body weights of the tumor-bearing animals and their tumor mass were measured afterwards to assess the mitogenic effect of rhEGF in the nude mice. RESULTS: Within the concentration range of 0.05-100mg.L(-1), rhEGF could increase the cell growth of normal 3T3 cells (cell growth rate 100% vs 102.8%, P【0.05), but partially restrain the gastric cancer cell growth. The latter effect was related to cell differentiation. In 15-60 microg/kg rhEGF groups, the mean implanted tumor mass of MKN-28 cell were 1.75 g, 1.91 g, 2.08 g/NS group 1.97 g (P】0.05), the mean tumor mass of SGC-7901 cell were 1.53 g, 1.07 g, 1.20 g/NS group 1.07 g (P】0.05), and for MKN-45 cell, the tumor mass were respectively 1.92 g, 1.29 g, 1.77 /NS group 1.82 g (P】0.05). So rhEGF had no obvious effect on implanted MKN-28, SGC-7901 and MKN-45 tumor growth. CONCLUSION: EGF has no stimulating effect on the human gastric cancer cell growth neither in vitro nor in vivo.展开更多
The nucleotide sequence deduced from the amino acid sequence of the scorpion insectotoxin AaIT was chemically synthesized and was expressed in Escherichia coli. The authenticity of this in vitro expressed peptide was ...The nucleotide sequence deduced from the amino acid sequence of the scorpion insectotoxin AaIT was chemically synthesized and was expressed in Escherichia coli. The authenticity of this in vitro expressed peptide was confirmed by N-terminal peptide sequencing. Two groups of bioassays, artificial diet incorporation assay and contact insecticidal effect assay, were carried out separately to verify the toxicity of this recombinant toxin. At the end of a 24 h experimental period, more than 60% of the testing diamondback moth (Plutella xylostella) larvae were killed in both groups with LC50 value of 18.4 microM and 0.70 microM respectively. Cytotoxicity assay using cultured Sf9 insect cells and MCF-7 human cells demonstrated that the toxin AaIT had specific toxicity against insect cells but not human cells. Only 0.13 microM recombinant toxin was needed to kill 50% of cultured insect cells while as much as 1.3 microM toxin had absolutely no effect on human cells. Insect cells produced obvious intrusions from their plasma membrane before broken up. We infer that toxin AaIT bind to a putative sodium channel in these insect cells and open the channel persistently, which would result in Na+ influx and finally cause destruction of insect cells.展开更多
Objective: To study the rules in the renaturation of recombinant antibody. Methods: Anti-TNF-a single domain (Sd) and single chain fragment variety(SCFv) antibodies were separated and purified under four conditions, i...Objective: To study the rules in the renaturation of recombinant antibody. Methods: Anti-TNF-a single domain (Sd) and single chain fragment variety(SCFv) antibodies were separated and purified under four conditions, including cosolvent redoxing, surface active solvent inducting, denaturant solvent inducting and the antigen of rhu TNFL-a inducting. Results: The dissolubility of renaturation products were between 6% - 11 %. Conclusion: These several conditions were good enough to the 2 antibody proteins and the best in them is the combination of the antigen inducting with affinity chromatography.展开更多
The construction of the shuttle, expression vector of human tumor necrosis factor alpha (hTNF-a) gene and its expression in a cyanobacterium Anabaena sp. PCC 7120 was reported. The 700-bp hTNF cDNA fragments have been...The construction of the shuttle, expression vector of human tumor necrosis factor alpha (hTNF-a) gene and its expression in a cyanobacterium Anabaena sp. PCC 7120 was reported. The 700-bp hTNF cDNA fragments have been recovered from plasmid pRL-rhTNF, then inserted downstream of the promoter PpsbA in the plasmid pRL439. The resultant intermediary plasmid pRL-TC has further been combined with the shuttle vector pDC-8 to get the shuttle, expression vector pDC-TNF. The expression of the rhTNF gene in Escherichia coli has been analyzed by SDS-PAGE and thin-layer scanning, and the results show that the expressed TNF protein with these two vectors is 16.9 percent (pRL-TC) and 15.0 percent (pDC-TNF) of the total proteins in the cells, respectively, while the expression level of TNF gene in plasmid pRL-rhTNF is only 11.8 percent. Combined with the participation of the conjugal and helper plasmids, pDC-TNF has been introduced into Anabaena sp PCC 7120 by triparental conjugative transfer, and the stable transgenic strains have been obtained. The existence of the introduced plasmid pDC-TNF in recom-binant cyanobacterial cells has been demonstrated by the results of the agarose electrophoresis with the extracted plasmid samples and Southern blotting with α-32P labeled hTNF cDNA probes, while the expression of the hTNF gene in Anabaena sp. PCC 7120 has been confirmed by the results of Western blotting with extracted protein samples and human TNF-alpha monoclonal antibodies. The cytotoxicity assays using the mouse cancer cell line L929 proved the cyto-toxicity of the TNF in the crude extracts from the transgenic cyanobacterium Anabaena sp. PCC 7120.展开更多
Background Human antigen R (HuR) is a ubiquitously expressed member of the ELAV family, and has relatively high cytoplasmic abundance in lung tissue regenerating after injury. In this study, we investigated whether ...Background Human antigen R (HuR) is a ubiquitously expressed member of the ELAV family, and has relatively high cytoplasmic abundance in lung tissue regenerating after injury. In this study, we investigated whether mitogen-activated protein kinase (MAPK)-activated protein kinase 2 (MK2) and HuR participate in the tumor necrosis factor (TNF)-induced expression of interleukin-6 (IL-6). Methods Human pulmonary microvascular endothelial cells were treated with TNF following short interfering RNAmediated knockdown of MK2 or HuR. Cell supernatants were collected to detect the mRNA and protein expression of IL-6 at different time points, The expression and half-life of IL-6 mRNA were then determined in cells that had been treated with actinomycin D. Finally, after knockdown of MK2, the cytoplasmic expression of HuR protein was analyzed using Western blotting. Results MK2 or HuR knockdown decreased both the mRNA and protein expression of IL-6 in TNF-stimulated cells. In MK2 knockdown cells, the half-life of IL-6 mRNA was reduced to 36 minutes, compared with 67 minutes in the control group. In HuR knockdown cells, the half-life of IL-6 mRNA decreased from 62 minutes to 24 minutes. Further analysis revealed that knockdown of MK2 resulted in reduced HuR protein expression in the cytoplasm. Conclusions MK2 regulates the TNF-induced expression of IL-6 by influencing the cytoplasmic levels of HuR.展开更多
Two tumor necrosis factor-a mutants MT1 (32Trp157Phe) and MT2 (2Lys30Ser- 32Trp157Phe) were constructed by site-directed mutagenesis. These mutants were soluble and over-expressed in E. coli. The purity of purified mu...Two tumor necrosis factor-a mutants MT1 (32Trp157Phe) and MT2 (2Lys30Ser- 32Trp157Phe) were constructed by site-directed mutagenesis. These mutants were soluble and over-expressed in E. coli. The purity of purified mutants was above 95% by serial chromatography. The results of Western blot indicated that these mutants could be cross-reactive with monoclonal antibody against native hTNF-a. Compared to parent hTNF-a, the cytotoxicity of these mutants on murine fibrosarcoma L929 cell lines reduced 4—5 orders of magnitude but was equivalent to that of native hTNF-a on human tumor cell lines. The LD50 of mutant MT1 was reduced to 0.34% of wild type and the dose of MT2 that resulted in 30% death of mice reduced to less than 1/700 that of parent hTNF-a.展开更多
A cDNA for human TNF-α (615bp) was isolated by means of polymerase chain reaction (PCR) using first strand cDNA from PMA-induced HL-60 cells as template. The result from sequencing the 615 bp cDNA fragment indicated ...A cDNA for human TNF-α (615bp) was isolated by means of polymerase chain reaction (PCR) using first strand cDNA from PMA-induced HL-60 cells as template. The result from sequencing the 615 bp cDNA fragment indicated that it corresponded to the entire sequence of mature human TNF coding region. Direct expression of mature human TNF was achieved using a plasmid pHT-1 constructed by ligation of the cDNA and a synthetic DNA. The IPTG-induced bacterial product (hTNF) showed cytotoxicity to mouse L-929 cells. The TNF activity was further identified by neutralization of a specific monoclonal antibody against human TNF-α. Approximately 80,000 units of activity were detected per ml of culture at A600=2.展开更多
文摘Objective: To evaluate the therapeutic efficacy of injecting recombinant mutant human tumor necrosis factor (rmhTNF) into pericardial cavity of carcinoma patients with malignant pericardial effusion. Methods: In 20 cases of malignant pericardial effusion, the intrapericardial catheter was inserted into pericardial cavity, and then rmhTNF of 1.5 × 107 U was infused. The infusion was repeated every 5-7 days with the total 4-6 times. If the effusion disappeared, rmhTNF was then used 2 more times and then the intrapericardial catheter was pulled out. Results: Of 20 patients, 14 were complete response (CR), 4 were partial response (PR) and 2 no change (NC). The disappearance of effusion in 6 cases lasted for more than 6 months. Conclusion: Injecting rmhTNF into pericardial cavity may be a better way to control malignant pericardial effusion and has mild side effects.
文摘Aim: To investigate the effect of inhibition of telomerase with human telomerase reverse transcriptase (hTERT) antisense on tumor necrosis factor-α (TNF-α-induced apoptosis in prostate cancer cells (PC3). Methods: Antisense phosphorothioate oligodeoxynucleotide (AS PS-ODN) was synthesized and purified. Telomerase activity was measured using the telomeric repeat amplification protocol (TRAP) and polymerase chain reaction enzyme-linked immunoassay (PCR-ELISA). hTERT mRNA was measured by reverse transcription PCR (RT-PCR) assay and gel-image system, hTERT protein was detected by immunochemistry and flow cytometry. Cell viability was detected by 3-(4, 5-dimethylthiazol-2-yl)-2,5-Diphenyltetrazolium (MTT) assay. Cell apoptosis was observed by morphological method and determined by flow cytometry. Results: The telomerase activity decreased with time after hTERT AS PS-ODN treatment. The levels of hTERT mRNA decreased with time after hTERT AS PS-ODN treatment, which appeared before the decline of the telomerase activity. The percentage of positive cells of hTERT protein declined with time after hTERT AS PS-ODN treatment, which appeared after the decline of hTERT mRNA. There was no difference in telomerase activity, hTERT mRNA and protein levels between hTERT sense phosphorothioate oligodeoxynucleotide (S PS-ODN) and the control group. The cell viability decreased with time after hTERT AS PS-ODN combined with TNF-α treatment. The percentage of apoptosis increased with time after hTERT AS PS-ODN combined with TNF-α treatment. There was no difference in cell viability and the percentage of apoptosis between hTERT S PS-ODN and the control group. Conclusion: hTERT AS PS-ODN can significantly inhibit telomerase activity by downregulating the hTERT mRNA and protein expression, and inhibition of telomerase with hTERT antisense can enhance TNF-α- induced apoptosis of PC3 cells.
基金the National Natural Science Foundation of China, No. 30772537
文摘BACKGROUND: Previous studies have reported that statins are less toxic to the human body and have greater antitumor activity; however, few studies have addressed the antitumor effect of statins combined with tumor necrosis factor-related apoptosis inducing ligand (TRAIL). OBJECTIVE: To explore the effect of TRAIL combined with mevastatin on the proliferation and apoptotic cell death of a human glioma cell line SWO-38, and to study its mechanism of action. DESIGN, TIME AND SETTING: An in vitro control experiment was performed at the Central Laboratory of the Third Hospital Affiliated to Sun Yat-sen University, between January and April 2009. MATERIALS: The human SWO-38 cell line was provided by Cell Research, Department of Animal Experimental Center of Sun Yat-sen University; human recombinant soluble TRAIL by R&D, USA; and mevastatin by Sigma, USA. METHODS: SWO-38 cells were separately incubated in TRAIL (100, 200, 300, 400, and 500 tJg/L) and mevastatin (5, 10, 20, 30, and 40 pmol/L) for 72 hours. In addition, SWO-38 cells were incubated in TRAIL (300 μg/L), mevastatin (30 μmol/L), and a solution containing both TRAIL and mevastatin for 12, 24, 48 and 72 hours. MAIN OUTCOME MEASURES: Cell proliferation was detected using methyl thiazolyl tetrazolium assay; cell apoptosis was observed using Hoechst 33258 staining and fluorescence microscopy and was measured using Annexin V/propidium iodide flow cytometry; TRAIL R1/DR4 and TRAIL R2/DR5 protein expressions levels were measured using indirect immunofluorescence staining combined with flow cytometry in the recombinant soluble TRAIL (rsTRAIL, 300 tJg/L), mevastatin (30 IJmol/L) and combination groups; TRAIL R1/DR4 and TRAIL R2/DR5 mRNA expression was detected using real-time polymerase chain reaction. RESULTS: rsTRAIL, mevastatin and their combination inhibited tumor proliferation in a time- and dose-dependent manner. The proliferation inhibitory rate and apoptosis rate of human SWO-38 cells in the combined group were significantly greater than the rsTRAIL or mevastatin alone group (P 〈 0.01). TRAIL R1/DR4 and TRAIL R2/DR5 protein and mRNA expressions were increased in the combination group compared with mevastatin or rsTRAIL alone after 72 hours (P 〈 0.01). CONCLUSION: Both rsTRAIL and mevastatin inhibit the proliferation and apoptosis of the human glioma cell line SWO-38, while their combination enhances the anti-tumor effect. The mechanism of action possibly correlates to the upregulation of TRAIL R1/DR4 and TRAIL R2/DR5 mRNA expression by mevastatin, thereby enhancing the cell sensitivity to rsTRAIL.
基金the National Natural Science Foundation of China,No.30671041the National Basic Research Program of China(973 Program),No. 2005CB623902
文摘BACKGROUND: Studies of several animal models of central nervous system diseases have shown that neural progenitor cells (NPCs) can migrate to injured tissues. Stromal cell-derived factor 1 alpha (SDF-la), and its primary physiological receptor CXCR4, have been shown to contribute to this process. OBJECTIVE: To investigate migration efficacy of human NPCs toward a SDF-1α gradient, and the regulatory roles of tumor necrosis factor-α (TNF-α) and interleukin-8 (IL-8) in SDF-1α/CXCR4 axis-induced migration of NPCs. DESIGN, TIME AND SETTING: An in vitro, randomized, controlled, cellular and molecular biology study was performed at the Laboratory of Department of Cell Biology, Medical College of Soochow University between October 2005 and November 2007. MATERIALS: SDF-1α and mouse anti-human CXCR4 fusion antibody were purchased from R&D Systems, USA. TNF-αwas purchased from Biomyx Technology, USA and IL-8 was kindly provided by the Biotechnology Research Institute of Soochow University. METHODS: NPCs isolated from forebrain tissue of 9 to 10-week-old human fetuses were cultured in vitro. The cells were incubated with 0, 20, and 40 ng/mL TNF-α, or 0, 20, and 40 ng/mL IL-8, for 48 hours prior to migration assay. For antibody-blocking experiments, cells were further pretreated with 0, 20, and 40 μg/mL mouse anti-human CXCR4 fusion antibody for 2 hours. Subsequently, the transwell assay and CXCR4 blockade experiments were performed to evaluate migration of human NPCs toward a SDF-1α gradient. Serum-free culture medium without SDF-1α served as the negative control. MAIN OUTCOME MEASURES: The transwell assay was performed to evaluate migration of human NPCs toward a SDF-1α gradient, which was blocked by fusion antibody against CXCR4. In addition, CXCR4 expression in human NPCs stimulated by TNF-α and IL-8 was measured by flow cytometry. RESULTS: Results from the transwell assay demonstrated that SDF-1α was a strong chemoattractant for human NPCs (P 〈 0.01), and 20 ng/mL produced the highest levels of migration. Anti-human CXCR4 fusion antibody significantly blocked the chemotactic effect (P 〈 0.05). Flow cytometry results showed that treatment with TNF-α and IL-8 resulted in increased CXCR4 expression and greater chemotaxis efficiency of NPCs towards SDF-1α(P 〈 0.01). CONCLUSION: These results demonstrated that SDF-la significantly attracted NPCs in vitro, and neutralizing anti-CXCR4 antibody could block part of this chemotactic function. TNF-α and IL-8 increased chemotaxis efficiency of NPCs towards the SDF-1αgradient by upregulating CXCR4 expression in NPCs.
基金Thanks to Peking University Hong Kong University of Science and Technology Medical Center for providing the research instruments and workplace.
文摘BACKGROUND Cartilage tissue engineering is a promising strategy for treating cartilage damage.Matrix formation by adipose-derived stem cells(ADSCs),which are one type of seed cell used for cartilage tissue engineering,decreases in the late stage of induced chondrogenic differentiation in vitro,which seriously limits research on ADSCs and their application.AIM To improve the chondrogenic differentiation efficiency of ADSCs in vitro,and optimize the existing chondrogenic induction protocol.METHODS Tumor necrosis factor-alpha(TNF-α)inhibitor was added to chondrogenic culture medium,and then Western blotting,enzyme linked immunosorbent assay,immunofluorescence and toluidine blue staining were used to detect the cartilage matrix secretion and the expression of key proteins of nuclear factor kappa-B(NF-κB)signaling pathway.RESULTS In this study,we found that the levels of TNF-αand matrix metalloproteinase 3 were increased during the chondrogenic differentiation of ADSCs.TNF-αthen bound to its receptor and activated the NF-κB pathway,leading to a decrease in cartilage matrix synthesis and secretion.Blocking TNF-αwith its inhibitors etanercept(1μg/mL)or infliximab(10μg/mL)significantly restored matrix formation.CONCLUSION Therefore,this study developed a combination of ADSC therapy and targeted anti-inflammatory drugs to optimize the chondrogenesis of ADSCs,and this approach could be very beneficial for translating ADSC-based approaches to treat cartilage damage.
基金Supported by:the Program of the Key Laboratory of Health Department of Jilin Province, No.2006079the Fortieth National Post-Doctoral Scientific Foundation,No. 20060400893
文摘BACKGROUND: Human tumor necrosis factor-like molecule 1A (hTL1A) is a strong T helper cell type 1 (Thl) co-stimulator. Guillain-Barre syndrome (GBS) is an autoimmune disorder of the nervous system, which is mediated by Thl cells. OBJECTIVE: To determine hTL1A expression in peripheral blood T lymphocytes of acute GBS children and the effects of hTL1A on secretion of interferon-γ. DESIGN, TIME AND SETTING: A randomized, controlled, neuroimmunological in vitro study was performed at the Central Laboratory of First Hospital of Jilin University, China from November 2005 to November 2007. MATERIALS: Venous blood samples were obtained from 6 healthy donors, aged 6-12 years (all routine blood examination items were normal), and 6 additional children with acute GBS, aged 6-12 years. The GBS children fell ill within 1 week and were not treated with hormones or immunoglobulin Purified recombinant human soluble tumor necrosis factor-like molecule 1A (rhsTL1A, 1 mg/mL, relative molecular mass 22 000, 6× His tag, soluble form) was supplied by the Central Laboratory of First Hospital of Jilin University, China. METHODS: Peripheral blood mononuclear cells were isolated from healthy donors using the standard Ficoll gradient centrifugation and were incubated in 96-well culture plates. The cells were assigned to the following groups: control (2 μg/mL phytohemagglutinin), 2μg/mL phytohemagglutinin + 25, 100 and 400 ng/mL rhsTL1A. T cell proliferation was quantified using the tritiated thymidine (3H-TdR) method. Serum interferon-γ levels in acute GBS children were detected by enzyme-linked immunosorbent assay (ELISA). The ratio of hTL1A-positive T cells to CD3-positive T cells in peripheral blood of acute GBS children was determined using flow cytometry. Following in vitro pre-activation of peripheral blood mononuclear cells by 2 μg/mL phytohemagglutinin, the peripheral blood mononuclear cells were treated with 400 ng/mL exogenous rhsTLIA. Finally, peripheral blood mononuclear cell-secreted interferon-γlevels were measured by ELISA. MAIN OUTCOME MEASURES: The following parameters were measured: rhsTLIA stimulation index to stimulate proliferation of T cells; the serum interferon-γ levels in acute GBS children; the ratio of hTL1A-positive cells to CD3-positive cells; the levels of interferon-γ secreted by peripheral blood mononuclear cells in acute GBS children, as well as rhsTL1A-stimulated interferon-γ levels. RESULTS: T cell proliferation assay revealed that the stimulation index in each rhsTL1A group was greater than the control group. The stimulation index of the 400 ng/mL rhsTL1A group was the greatest. Serum interferon-γ levels in acute GBS children were significantly greater than the control group (P 〈 0.05). The ratio of hTLIA+ CD3+ T cells to CD3+ T cells in acute GBS children was significantly greater than the control group (P 〈 0.01 ). Phytohemagglutinin stimulated peripheral blood mononuclear cells to a greater extent than 400 ng/mL rhsTL1A in the acute GBS group, and the secreted interferon-γ levels were significantly increased (P 〈 0.05). CONCLUSION: In T cells pre-activated with 2 μg/mL phytohemagglutinin, proliferation was effectively increased with 400 ng/mL rhsTL1A treatment. Expression of hTLIA was increased in activated T cells from peripheral blood of acute GBS children, followed by increased interferon-γ secretion. These mechanisms are considered to be part of the pathological process that induces the secretion of inflammatory cytokines in GBS syndrome.
文摘Acute myocardial infarction (AMI) is an acute cardiovascular emergency. This study was undertaken to assess the effect of tumor necrosis factor-a (TNF-a) on ventricular arrhythmias induced byAMI in rats in vivo. Two hundred and forty male Wistar rats were randomized into a sham- operation group, an AMI group, and a recombinant human tumor necrosis factor receptor:Fc fusion protein(rhTNFR:Fc) group. Acute anterior wall myocardial infarction was produced in the AMI group by ligating the left anterior descending coronary artery (LAD), and there was no ligation but operation in the sham-operation group. The rhTNFR:Fc group was treated with rhTNFR:Fc(10 mg/kg), a TNF-a antagonist, 24 hours before LAD ligation. The spontaneous and induced programmed electrical stimulation ventricular arrhythmias were recorded at baseline and 10 minutes, 20 minutes, 30 minutes, 60 minutes, 3 hours, 6 hours and 12 hours after ligation. At the same time the protein and mRNA expression levels of TNF-a among different groups were detected by histochemistry and real-time fluorescent quantitative PCR. Expression of TNF-a increased markedly from 10 minutes after infarction, peaked at 20-30 minutes, and returned to baseline gradually in the AMI group and rhTNFR:Fc group. The time- windows of spontaneous and induced ventricular arrhythmias were similar. Compared with the AMI group, the rhTNFR:Fc group showed a lesser expression of TNF-a protein and a lower incidence of ventricular arrhythmias (P〈0.05). There was no obvious change in the sham-operation group. The expression of TNF-a induced by AMI could contribute to the onset of ventricular arrhythmias.
基金the grant from Medical Science Foundation of Guangdong Province,No.A2006334the Natural Science Foundation of Guangdong Province,No.06105246,No.9151040701000008the Science and Technology Project of Guangzhou City,No.2007J1-C0041
文摘BACKGROUND: Previous studies of curcumin have focused mainly on its cytotoxic properties for antitumor therapy. There are few studies addressing the application of curcumin in the prevention and treatment of nervous system diseases. OBJECTIVE: To observe the protective effect of curcumin against tumor necrosis factor-alpha (TNF-α)-induced neuronal damage in the rat hippocampus and to explore the intervention effect of curcumin on Ca^2+ influx following neuronal damage. DESIGN, TIME AND SETTING: A cell morphological and physiological study was performed at the Institute of Brain Research, Medical College of Jinan University, China, from December 2006 to June 2007. MATERIALS: Curcumin (Sigma, USA) and TNF-α (Sigma, USA) were used in this study. METHODS: Hippocampal neurons were isolated from one-day neonatal rats and primarily cultured for 5 days. Following this they received 1 pmol/L curcumin and 100 ng/mL TNF-a pre-treatment. Dynamic morphological changes were observed for 1 hour by inverted microscopy. At 48 hours post-treatment, static morphological characteristics of the neurons were observed using inverted microscopy. Subsequently, hippocampal neurons were primarily cultured for 7 days, after receiving 1 pmol/L curcumJn and 4.5 ng/mL TNF-a pre-treatment. Intracellular free Ca^2+ was measured using Fluo 3/acetoxymethyl ester. MAIN OUTCOME MEASURES: Effects of curcumin on TNF-a-induced neuronal damage and Ca^2+ influx in the rat hippocampus were measured. RESULTS: Following curcumin treatment, TNF-a-induced neurons grew as normal. TNF-a induced a rapid Ca^2+ influx into the neuronal cytoplasm; however, Ca2+ fluorescence intensity only slightly increased when neurons were co-perfused with curcumin and TNF-α. CONCLUSION: Curcumin has a protective effect on rat hippocampal neurons possibly by reducing the TNF-α-induced rapid Ca^2+ influx into neuronal cytoplasm and by maintaining the Ca^2+ homeostasis.
文摘Using light microscopy and electron microscopy, we observed the morphological changes inheuman hepatocellular carcinoma cell line (SMMC-7721) treated with tumor necrosis tumor necrosis factor (TNF)and the cytocidal effect of TNF on the heterotransplanted human hepatocellular carcinoma. It wasfound that the changes of the injury occurred earlier in the cell membranes than in the nuclei duringthe course of TNF killing of SMMC-7721 cells and there were similar lesions around the necroticarea in the heterotransplanted human hepatocellular carcinoma in the nude mice as compared withthose produced in SMMC-7721 cells. In addition, the determination of the DNA content in TNF-treated SMMC-7721 cells and controls revealed no significant difference between them. On the basisof these results and Darzynkiewicz’s proposals, it is suggested that TNF exerts its tumor-selectivekilling effect by binding to a specific to a specific plasma membrane receptor to disturb synthesis or assembly ofcell membrane components, thus causing the plasma membrane injury and finally cell lysis.
文摘AIM: Epidermal growth factor (EGF) plays an important role in the regulation of gastrointestinal tissue growth and development, and it can stimulate epithelial proliferation, cell differentiation and growth. It has been established that the EGF can promote gastric cytoprotection and ulcer healing. But the potential ability of EGF to regulate the gastric cancer growth is unknown. This study is to investigate the influence of EGF on human gastric cancer cell and the implanted tumor growth of nude mice. METHODS: The cell growth rates of human gastric adenocarcinoma cell lines MKN-28, MKN-45, SGC-7901 and normal human gastric epithelial cells 3T3 were assessed when incubated with recombinant human EGF (rhEGF, 0.05, 0.1, 0.5, 1.0, 10, 50, 100 mg.L(-1)) using MTT method. The cells of MKN-28, MKN-45, SGC-7901 (gastric cancer tissue 1.5mm(3)) were implanted in the BALB/cA nude mice for 10 days.The EGF was given intraperitoneally (15, 30, 60 microg.kg(-1)) for 3 weeks. The body weights of the tumor-bearing animals and their tumor mass were measured afterwards to assess the mitogenic effect of rhEGF in the nude mice. RESULTS: Within the concentration range of 0.05-100mg.L(-1), rhEGF could increase the cell growth of normal 3T3 cells (cell growth rate 100% vs 102.8%, P【0.05), but partially restrain the gastric cancer cell growth. The latter effect was related to cell differentiation. In 15-60 microg/kg rhEGF groups, the mean implanted tumor mass of MKN-28 cell were 1.75 g, 1.91 g, 2.08 g/NS group 1.97 g (P】0.05), the mean tumor mass of SGC-7901 cell were 1.53 g, 1.07 g, 1.20 g/NS group 1.07 g (P】0.05), and for MKN-45 cell, the tumor mass were respectively 1.92 g, 1.29 g, 1.77 /NS group 1.82 g (P】0.05). So rhEGF had no obvious effect on implanted MKN-28, SGC-7901 and MKN-45 tumor growth. CONCLUSION: EGF has no stimulating effect on the human gastric cancer cell growth neither in vitro nor in vivo.
基金This work was supported by a grant from 863High Technology Program,Chinese Ministry of Sci-ence and Technology
文摘The nucleotide sequence deduced from the amino acid sequence of the scorpion insectotoxin AaIT was chemically synthesized and was expressed in Escherichia coli. The authenticity of this in vitro expressed peptide was confirmed by N-terminal peptide sequencing. Two groups of bioassays, artificial diet incorporation assay and contact insecticidal effect assay, were carried out separately to verify the toxicity of this recombinant toxin. At the end of a 24 h experimental period, more than 60% of the testing diamondback moth (Plutella xylostella) larvae were killed in both groups with LC50 value of 18.4 microM and 0.70 microM respectively. Cytotoxicity assay using cultured Sf9 insect cells and MCF-7 human cells demonstrated that the toxin AaIT had specific toxicity against insect cells but not human cells. Only 0.13 microM recombinant toxin was needed to kill 50% of cultured insect cells while as much as 1.3 microM toxin had absolutely no effect on human cells. Insect cells produced obvious intrusions from their plasma membrane before broken up. We infer that toxin AaIT bind to a putative sodium channel in these insect cells and open the channel persistently, which would result in Na+ influx and finally cause destruction of insect cells.
基金Supported by National Natural Science Foundation of China, No. 39670695
文摘Objective: To study the rules in the renaturation of recombinant antibody. Methods: Anti-TNF-a single domain (Sd) and single chain fragment variety(SCFv) antibodies were separated and purified under four conditions, including cosolvent redoxing, surface active solvent inducting, denaturant solvent inducting and the antigen of rhu TNFL-a inducting. Results: The dissolubility of renaturation products were between 6% - 11 %. Conclusion: These several conditions were good enough to the 2 antibody proteins and the best in them is the combination of the antigen inducting with affinity chromatography.
基金Project supported by the National Natural Science Foundation of China (Grant No. 39280016).
文摘The construction of the shuttle, expression vector of human tumor necrosis factor alpha (hTNF-a) gene and its expression in a cyanobacterium Anabaena sp. PCC 7120 was reported. The 700-bp hTNF cDNA fragments have been recovered from plasmid pRL-rhTNF, then inserted downstream of the promoter PpsbA in the plasmid pRL439. The resultant intermediary plasmid pRL-TC has further been combined with the shuttle vector pDC-8 to get the shuttle, expression vector pDC-TNF. The expression of the rhTNF gene in Escherichia coli has been analyzed by SDS-PAGE and thin-layer scanning, and the results show that the expressed TNF protein with these two vectors is 16.9 percent (pRL-TC) and 15.0 percent (pDC-TNF) of the total proteins in the cells, respectively, while the expression level of TNF gene in plasmid pRL-rhTNF is only 11.8 percent. Combined with the participation of the conjugal and helper plasmids, pDC-TNF has been introduced into Anabaena sp PCC 7120 by triparental conjugative transfer, and the stable transgenic strains have been obtained. The existence of the introduced plasmid pDC-TNF in recom-binant cyanobacterial cells has been demonstrated by the results of the agarose electrophoresis with the extracted plasmid samples and Southern blotting with α-32P labeled hTNF cDNA probes, while the expression of the hTNF gene in Anabaena sp. PCC 7120 has been confirmed by the results of Western blotting with extracted protein samples and human TNF-alpha monoclonal antibodies. The cytotoxicity assays using the mouse cancer cell line L929 proved the cyto-toxicity of the TNF in the crude extracts from the transgenic cyanobacterium Anabaena sp. PCC 7120.
基金This study was supported by the National Natural Science Foundation of China (No. 81270138), the Natural Science Foundation of Jiangsu Province (No. BK2011657 and No. BK20130402), and the Medical Technology Innovation Foundation of Nanjing Military Command (No. CWS 12J008).
文摘Background Human antigen R (HuR) is a ubiquitously expressed member of the ELAV family, and has relatively high cytoplasmic abundance in lung tissue regenerating after injury. In this study, we investigated whether mitogen-activated protein kinase (MAPK)-activated protein kinase 2 (MK2) and HuR participate in the tumor necrosis factor (TNF)-induced expression of interleukin-6 (IL-6). Methods Human pulmonary microvascular endothelial cells were treated with TNF following short interfering RNAmediated knockdown of MK2 or HuR. Cell supernatants were collected to detect the mRNA and protein expression of IL-6 at different time points, The expression and half-life of IL-6 mRNA were then determined in cells that had been treated with actinomycin D. Finally, after knockdown of MK2, the cytoplasmic expression of HuR protein was analyzed using Western blotting. Results MK2 or HuR knockdown decreased both the mRNA and protein expression of IL-6 in TNF-stimulated cells. In MK2 knockdown cells, the half-life of IL-6 mRNA was reduced to 36 minutes, compared with 67 minutes in the control group. In HuR knockdown cells, the half-life of IL-6 mRNA decreased from 62 minutes to 24 minutes. Further analysis revealed that knockdown of MK2 resulted in reduced HuR protein expression in the cytoplasm. Conclusions MK2 regulates the TNF-induced expression of IL-6 by influencing the cytoplasmic levels of HuR.
文摘Two tumor necrosis factor-a mutants MT1 (32Trp157Phe) and MT2 (2Lys30Ser- 32Trp157Phe) were constructed by site-directed mutagenesis. These mutants were soluble and over-expressed in E. coli. The purity of purified mutants was above 95% by serial chromatography. The results of Western blot indicated that these mutants could be cross-reactive with monoclonal antibody against native hTNF-a. Compared to parent hTNF-a, the cytotoxicity of these mutants on murine fibrosarcoma L929 cell lines reduced 4—5 orders of magnitude but was equivalent to that of native hTNF-a on human tumor cell lines. The LD50 of mutant MT1 was reduced to 0.34% of wild type and the dose of MT2 that resulted in 30% death of mice reduced to less than 1/700 that of parent hTNF-a.
文摘A cDNA for human TNF-α (615bp) was isolated by means of polymerase chain reaction (PCR) using first strand cDNA from PMA-induced HL-60 cells as template. The result from sequencing the 615 bp cDNA fragment indicated that it corresponded to the entire sequence of mature human TNF coding region. Direct expression of mature human TNF was achieved using a plasmid pHT-1 constructed by ligation of the cDNA and a synthetic DNA. The IPTG-induced bacterial product (hTNF) showed cytotoxicity to mouse L-929 cells. The TNF activity was further identified by neutralization of a specific monoclonal antibody against human TNF-α. Approximately 80,000 units of activity were detected per ml of culture at A600=2.