AIM: To evaluate tumor necrosis factor-α converting enzyme(TACE) methylation status in patients with chronic hepatitis B(CHB).METHODS: Eighty patients with hepatitis B e antigen(HBe Ag)-positive CHB, 80 with HBe Ag-n...AIM: To evaluate tumor necrosis factor-α converting enzyme(TACE) methylation status in patients with chronic hepatitis B(CHB).METHODS: Eighty patients with hepatitis B e antigen(HBe Ag)-positive CHB, 80 with HBe Ag-negative CHB, and 40 healthy controls(HCs) were randomly enrolled in this study. Genomic DNA was extracted from peripheral blood mononuclear cells and methylation status of TACE promoter was determined by methylation-specific polymerase chain reaction. The clinical and laboratory parameters were collected.RESULTS: One hundred and thirty of 160 patients with CHB(81.25%) and 38 of 40 HCs(95%) displayed TACE promoter methylation. The difference was significant(χ2 = 4.501, P < 0.05). TACE promoter methylation frequency in HBe Ag-positive CHB(58/80, 72.5%) was significantly lower than that in HBe Ag-negative CHB(72/80, 90%; χ2 = 8.041, P < 0.01) and HCs(χ2 = 8.438, P < 0.01). However, no significant difference was observed in the methylation frequency between HBe Agnegative CHB and HCs(χ2 = 0.873, P > 0.05). In the HBe Ag-positive group, TACE methylation frequency was significantly negatively correlated with HBe Ag(r =-0.602, P < 0.01), alanine aminotransferase(r =-0.461, P < 0.01) and aspartate aminotransferase(r =-0.329, P < 0.01). CONCLUSION: Patients with HBe Ag-positive CHB have aberrant demethylation of the TACE promoter, which may potentially serve as a biomarker for HBe Ag seroconversion.展开更多
Background Chronic obstructive pulmonary disease （COPD） is associated not only with airway inflammation characterized by mucin hypersecretion but also with systemic inflammation. Tumor necrosis factor alpha （TNF-α...Background Chronic obstructive pulmonary disease （COPD） is associated not only with airway inflammation characterized by mucin hypersecretion but also with systemic inflammation. Tumor necrosis factor alpha （TNF-α） is found to take part in systemic inflammation, and ErbB3 plays an important role in mucin hypersecretion of COPD. Since TNF-α converting enzyme （TACE） is involved in the activation of both TNF-α and ErbB3, we established rat models of COPD to investigate the expressions of TACE, TNF-α and ErbB3 and to explore the correlations among TACE,TNF-α and ErbB3 respectively. Methods Thirty Wistar male rats were randomly divided into COPD group （group C, n=10）, saline solution parallel group （group P, n=-8）, and normal control group （group N, n=-8）. Group C was challenged with passive cigarette smoking and intratracheal instillation of lipopolysaccharide. Six weeks later pulmonary functions were tested, bronchoalveolar fluid and arterial blood gases were assayed, and histopathological evaluations were performed in turn. The expressions of TACE, TNF-α and ErbB3 in lungs of all rats were determined histochemically. Results The expressions of TACE, TNF-α and ErbB3 were significantly higher in group C than in group N （P〈0.01）. The contents of TNF-α in serum （P〈0.01） and bronchoalveolar lavage fluid （BALF） （P〈0.01） were elevated more significantly in group C than in group N. A positive correlation existed between TACE and TNF-α （r=0.784, P〈0.01） and between TACE and ErbB3 （r=0.526, P〈0.01） respectively. Conclusions TNF-α and ErbB3 are involved in the pathogenesis of COPD. TACE contributes to the progress of COPD indirectly through the function of TNF-α and ErbB3.展开更多
AIM:To determine if the cytotail of the principal sheddase tumor necrosis factor-α converting enzyme (TACE;ADAM17) controls protein ectodomain shedding.METHODS:Site-directed mutagenesis was performed to derive TACE v...AIM:To determine if the cytotail of the principal sheddase tumor necrosis factor-α converting enzyme (TACE;ADAM17) controls protein ectodomain shedding.METHODS:Site-directed mutagenesis was performed to derive TACE variants. The resulting TACE expression plasmids with amino acid substitutions in the extracel-lular,cysteine-rich disintegrin domain (CRD) and/or deleted cytotail,along with an expression vector for the enhanced green fluorescence protein were transfected into shedding-defective M1 mutants stably expressing transmembrane L-selectin or transforming growth factor (TGF)-α. The expression levels of the TACE substrates at the cell surface were determined by flow cytometry. RESULTS:Consistent with published data,a single point mutation (C600Y) in the CRD led to shedding defi-ciency. However,removal of the cytotail from the C600Y TACE variant partially restored ectodomain cleavage of TGF-α and L-selectin. Cytotail-deleted mutants with any other substituting amino acid residues in place of Cys600 displayed similar function compared with tail-less C600Y TACE.CONCLUSION:The cytotail plays an inhibitory role,which becomes evident when it is removed from an enzyme with another mutation that affects the enzyme function.展开更多
The effects of inhibitors of TNFα converting enzyme (TACE) on TNFα secretion were studied to develop an approach to interfere inflammation processes. The HL-60 cell lines were stimulated in vitro with LPS intravenou...The effects of inhibitors of TNFα converting enzyme (TACE) on TNFα secretion were studied to develop an approach to interfere inflammation processes. The HL-60 cell lines were stimulated in vitro with LPS intravenously for different time to establish the cellular model of inflammation and simultaneously induce in vivo inflammation animal model by LPS The cytotoxic effects of soluble TNFa were checked using MTT colorimetric method to determine the rate of cell proliferation. The level of expression of TACE was detected by using RT-PCR, FCM and immuno-histochemical technique respectively. It was found Chinese medicine Reduqing (RDQ) could inhibit the transcription of TNFa mRNA induced by LPS stimulation (P<0. 01, compared with the control). The anti-oligodeoxyribonucleotide (anti-ODN) of TNFα mRNA could inhibit 78. 9 % of TNFα secretion. The mimic peptides of TACE substrates with hydroxamine group showed potency in vivo and in vitro a-gainst converting of pro-TNFα. It was concluded that all the three types of TACE inhibitors can regulate the expression of TACE at different levels and inhibit sTNFα secretion, indicating TACE is a novel target for inflammation therapy.展开更多
Summary： To obtain the recombinant tumor necrosis factor-α converting enzyme （TACE） ectodomain and use it as a selective molecule for the screening of TACE peptide inhibitors, the cDNA coding catalytic domain （T...Summary： To obtain the recombinant tumor necrosis factor-α converting enzyme （TACE） ectodomain and use it as a selective molecule for the screening of TACE peptide inhibitors, the cDNA coding catalytic domain （TS00） and full-length ectodomain （T1300） of TACE were amplified by RT-PCR, and the expres.sion plasmids were constructed by inserting T800 and T1300 into plasmid pET-28a and pET-28c respectively. The recombinant TS00 and T1300 were induced by IPTG, and SDS-PAGE and Western blotting analysis results revealed that TS00 and T1300 were highly expressed in the form of inclusion body. After Ni^2＋-NTA resin affinity chromatography, the recombinant proreins were used in the screening of TACE-binding peptides from phage display peptide library respectively. After 4 rounds of biopanning, the positive phage clones were analyzed by ELISA, competitive inhibition assay and DNA sequencing. A common amino acid sequence （TRWLVYFSRPYLVAT） was found and synthesized. The synthetic peptide could inhibit the TNF-α release from LPS-stimulated human peripheral blood mononuclear cells （PBMC） up to 60.3%. FACS analysis revealed that the peptide mediated the accumulation of TNF-α on the cell surface. These results demonstrate that the TACE binding peptide is an effective antagonist of TACE.展开更多
基金Supported by Key Project of Chinese Ministry of Science and Technology,No.2012ZX10002007 and No.2013ZX10002001National Natural Science Foundation of China,No.81171579,No.81201287 and No.81371832Science and Technology Development Plan of Shandong Province,China,No.2014GSF118068
文摘AIM: To evaluate tumor necrosis factor-α converting enzyme(TACE) methylation status in patients with chronic hepatitis B(CHB).METHODS: Eighty patients with hepatitis B e antigen(HBe Ag)-positive CHB, 80 with HBe Ag-negative CHB, and 40 healthy controls(HCs) were randomly enrolled in this study. Genomic DNA was extracted from peripheral blood mononuclear cells and methylation status of TACE promoter was determined by methylation-specific polymerase chain reaction. The clinical and laboratory parameters were collected.RESULTS: One hundred and thirty of 160 patients with CHB(81.25%) and 38 of 40 HCs(95%) displayed TACE promoter methylation. The difference was significant(χ2 = 4.501, P < 0.05). TACE promoter methylation frequency in HBe Ag-positive CHB(58/80, 72.5%) was significantly lower than that in HBe Ag-negative CHB(72/80, 90%; χ2 = 8.041, P < 0.01) and HCs(χ2 = 8.438, P < 0.01). However, no significant difference was observed in the methylation frequency between HBe Agnegative CHB and HCs(χ2 = 0.873, P > 0.05). In the HBe Ag-positive group, TACE methylation frequency was significantly negatively correlated with HBe Ag(r =-0.602, P < 0.01), alanine aminotransferase(r =-0.461, P < 0.01) and aspartate aminotransferase(r =-0.329, P < 0.01). CONCLUSION: Patients with HBe Ag-positive CHB have aberrant demethylation of the TACE promoter, which may potentially serve as a biomarker for HBe Ag seroconversion.
文摘Background Chronic obstructive pulmonary disease （COPD） is associated not only with airway inflammation characterized by mucin hypersecretion but also with systemic inflammation. Tumor necrosis factor alpha （TNF-α） is found to take part in systemic inflammation, and ErbB3 plays an important role in mucin hypersecretion of COPD. Since TNF-α converting enzyme （TACE） is involved in the activation of both TNF-α and ErbB3, we established rat models of COPD to investigate the expressions of TACE, TNF-α and ErbB3 and to explore the correlations among TACE,TNF-α and ErbB3 respectively. Methods Thirty Wistar male rats were randomly divided into COPD group （group C, n=10）, saline solution parallel group （group P, n=-8）, and normal control group （group N, n=-8）. Group C was challenged with passive cigarette smoking and intratracheal instillation of lipopolysaccharide. Six weeks later pulmonary functions were tested, bronchoalveolar fluid and arterial blood gases were assayed, and histopathological evaluations were performed in turn. The expressions of TACE, TNF-α and ErbB3 in lungs of all rats were determined histochemically. Results The expressions of TACE, TNF-α and ErbB3 were significantly higher in group C than in group N （P〈0.01）. The contents of TNF-α in serum （P〈0.01） and bronchoalveolar lavage fluid （BALF） （P〈0.01） were elevated more significantly in group C than in group N. A positive correlation existed between TACE and TNF-α （r=0.784, P〈0.01） and between TACE and ErbB3 （r=0.526, P〈0.01） respectively. Conclusions TNF-α and ErbB3 are involved in the pathogenesis of COPD. TACE contributes to the progress of COPD indirectly through the function of TNF-α and ErbB3.
基金Supported by Grants from the National Institutes of Health,No.AG029859 the National Center of the American Heart Association,No.0330335Nthe New Jersey Commission on Cancer Research(NJCCR703010)to Fan H
文摘AIM:To determine if the cytotail of the principal sheddase tumor necrosis factor-α converting enzyme (TACE;ADAM17) controls protein ectodomain shedding.METHODS:Site-directed mutagenesis was performed to derive TACE variants. The resulting TACE expression plasmids with amino acid substitutions in the extracel-lular,cysteine-rich disintegrin domain (CRD) and/or deleted cytotail,along with an expression vector for the enhanced green fluorescence protein were transfected into shedding-defective M1 mutants stably expressing transmembrane L-selectin or transforming growth factor (TGF)-α. The expression levels of the TACE substrates at the cell surface were determined by flow cytometry. RESULTS:Consistent with published data,a single point mutation (C600Y) in the CRD led to shedding defi-ciency. However,removal of the cytotail from the C600Y TACE variant partially restored ectodomain cleavage of TGF-α and L-selectin. Cytotail-deleted mutants with any other substituting amino acid residues in place of Cys600 displayed similar function compared with tail-less C600Y TACE.CONCLUSION:The cytotail plays an inhibitory role,which becomes evident when it is removed from an enzyme with another mutation that affects the enzyme function.
基金This project was supported by a grant from National Natural Sciences Foundation of China(No.30070722).
文摘The effects of inhibitors of TNFα converting enzyme (TACE) on TNFα secretion were studied to develop an approach to interfere inflammation processes. The HL-60 cell lines were stimulated in vitro with LPS intravenously for different time to establish the cellular model of inflammation and simultaneously induce in vivo inflammation animal model by LPS The cytotoxic effects of soluble TNFa were checked using MTT colorimetric method to determine the rate of cell proliferation. The level of expression of TACE was detected by using RT-PCR, FCM and immuno-histochemical technique respectively. It was found Chinese medicine Reduqing (RDQ) could inhibit the transcription of TNFa mRNA induced by LPS stimulation (P<0. 01, compared with the control). The anti-oligodeoxyribonucleotide (anti-ODN) of TNFα mRNA could inhibit 78. 9 % of TNFα secretion. The mimic peptides of TACE substrates with hydroxamine group showed potency in vivo and in vitro a-gainst converting of pro-TNFα. It was concluded that all the three types of TACE inhibitors can regulate the expression of TACE at different levels and inhibit sTNFα secretion, indicating TACE is a novel target for inflammation therapy.
文摘Summary： To obtain the recombinant tumor necrosis factor-α converting enzyme （TACE） ectodomain and use it as a selective molecule for the screening of TACE peptide inhibitors, the cDNA coding catalytic domain （TS00） and full-length ectodomain （T1300） of TACE were amplified by RT-PCR, and the expres.sion plasmids were constructed by inserting T800 and T1300 into plasmid pET-28a and pET-28c respectively. The recombinant TS00 and T1300 were induced by IPTG, and SDS-PAGE and Western blotting analysis results revealed that TS00 and T1300 were highly expressed in the form of inclusion body. After Ni^2＋-NTA resin affinity chromatography, the recombinant proreins were used in the screening of TACE-binding peptides from phage display peptide library respectively. After 4 rounds of biopanning, the positive phage clones were analyzed by ELISA, competitive inhibition assay and DNA sequencing. A common amino acid sequence （TRWLVYFSRPYLVAT） was found and synthesized. The synthetic peptide could inhibit the TNF-α release from LPS-stimulated human peripheral blood mononuclear cells （PBMC） up to 60.3%. FACS analysis revealed that the peptide mediated the accumulation of TNF-α on the cell surface. These results demonstrate that the TACE binding peptide is an effective antagonist of TACE.
