AIM: To set up a new method to detect tissue inhibitors of metalloproteinase-1 and -2(TIMP-1 and TIMP-2) in sera of patients with hepatic cirrhosis, and to investigate the expression and location of TIMP-1 and TIMP-2 ...AIM: To set up a new method to detect tissue inhibitors of metalloproteinase-1 and -2(TIMP-1 and TIMP-2) in sera of patients with hepatic cirrhosis, and to investigate the expression and location of TIMP-1 and TIMP-2 in liver tissue of patients with hepatic cirrhosis, and the correlation between TIMPs in liver and those in sera so as to discuss whether TIMPs can be used as a diagnosis index of hepatic fibrosis. METHODS: The monoclonal antibodies (McAbs) of TIMP-1 and TIMP-2 were used to sensitize erythrocytes, and solid-phase absorption to sensitized erythrocytes (SPASE) was used to detect TIMP-1 and TIMP-2 in the sera of patients with hepatic cirrhosis. Meanwhile, with the method of in situ hybridization and immunohistochemistry, we studied the mRNA expression and antigen location of TIMP-1 and TIMP-2 in the livers of 40 hepatic cirrhosis patients with pathologic diagnosis. RESULTS: With SPASE, they were 16.4% higher in the acute hepatitis group, 33.3% higher in the chronic hepatitis group, and the positive rates were 73.6% and 61.2% respectively in sera of hepatic cirrhosis patients, which were remarkably higher than those in chronic hepatitis and acute hepatitis group (P【0.001). In 40 samples of hepatic cirrhosis tissues, all of them showed positive expression of TIMP-1 and TIMP-2 mRNA detected with immunohistochemistry or in situ hybridization (positive rate was 100%). Expression of TIMPs in different degrees could be found in liver tissue with cirrhosis. TIMPs were located in cytoplasm of liver cells of patients with hepatic cirrhosis. There was a significant correlation between serum TIMPs level and liver TIMPs level. CONCLUSION: SPASE is a useful method to detect the TIMP-1 and TIMP-2 in sera of patients with hepatic cirrhosis, and TIMP-1 and TIMP-2 can be considered as a useful diagnostic index of hepatic fibrosis, especially TIMP-1.展开更多
The Keap1–Nrf2–ARE pathway is an important antioxidant defense mechanism that protects cells from oxidative stress and the Keap1–Nrf2 protein–protein interaction(PPI) has become an important drug target to upregul...The Keap1–Nrf2–ARE pathway is an important antioxidant defense mechanism that protects cells from oxidative stress and the Keap1–Nrf2 protein–protein interaction(PPI) has become an important drug target to upregulate the expression of ARE-controlled cytoprotective oxidative stress response enzymes in the development of therapeutic and preventive agents for a number of diseases and conditions. However, most known Nrf2 activators/ARE inducers are indirect inhibitors of Keap1–Nrf2PPI and they are electrophilic species that act by modifying the sulfhydryl groups of Keap1's cysteine residues. The electrophilicity of these indirect inhibitors may cause "off-target" side effects by reacting with cysteine residues of other important cellular proteins. Efforts have recently been focused on the development of direct inhibitors of Keap1–Nrf2 PPI. This article reviews these recent research efforts including the development of high throughput screening assays, the discovery of peptide and small molecule direct inhibitors, and the biophysical characterization of the binding of these inhibitors to the target Keap1 Kelch domain protein. These non-covalent direct inhibitors of Keap1–Nrf2 PPI could potentially be developed into effective therapeutic or preventive agents for a variety of diseases and conditions.展开更多
Biotic and abiotic stress lead to elevated levels of jasmonic acid （JA） and its derivatives and activation of the biosynthesis of nicotine and related pyridine alkaloids in cultivated tobacco （Nicotiana tabacum L....Biotic and abiotic stress lead to elevated levels of jasmonic acid （JA） and its derivatives and activation of the biosynthesis of nicotine and related pyridine alkaloids in cultivated tobacco （Nicotiana tabacum L.）. Among the JA- responsive genes is NtPMTla, encoding putrescine N-methyl transferase, a key regulatory enzyme in nicotine formation. We have characterized three genes （NtMYC2a, b, c） encoding basic helix-loop-helix （bHLH） transcription factors （TFs） whose expression is rapidly induced by JA and that specifically activate JA-inducible NtPMTla expression by binding a G-box motif within the NtPMTla promoter in in vivo and in vitro assays. Using split-YFP assays, we further show that, in the absence of JA, NtMYC2a and NtMYC2b are present as nuclear complexes with the NtJAZ1 repressor. RNA interference （RNAi）-mediated knockdown of NtMYC2a and NtMYC2b expression results in significant decreases in JA-inducible NtPMTla transcript levels, as well as reduced levels of transcripts encoding other enzymes involved in nicotine and minor alkaloid biosynthesis, in- cluding an 80-90% reduction in the level of transcripts encoding the putative nicotine synthase gene NtA662. In contrast, ectopic overexpression of NtMYC2a and NtMYC2b had no effect on NtPMTla expression in the presence or absence of exogenously added JA. These data suggest that NtMYC2a, b, c are required components of JA-inducible expression of multiple genes in the nicotine biosynthetic pathway and may act additively in the activation of JA responses.展开更多
目的建立同时测定赤芍Paeoniae Rubra Radix和白芍Paeoniae Alba Radix中没食子酸、没食子酸甲酯、芍药内酯苷、芍药苷、1,2,3,4,6-五没食子酰葡萄糖、苯甲酰芍药苷的HPLC方法,测定和比较32批不同产地和收集地赤芍和白芍中6种化学成分...目的建立同时测定赤芍Paeoniae Rubra Radix和白芍Paeoniae Alba Radix中没食子酸、没食子酸甲酯、芍药内酯苷、芍药苷、1,2,3,4,6-五没食子酰葡萄糖、苯甲酰芍药苷的HPLC方法,测定和比较32批不同产地和收集地赤芍和白芍中6种化学成分的量。方法采用HPLC法进行测定,流动相为乙腈-0.1%磷酸水溶液,体积流量0.8 m L/min,柱温30℃,检测波长为230 nm和270 nm。结果结果显示,没食子酸、没食子酸甲酯、芍药内酯苷、芍药苷、1,2,3,4,6-五没食子酰葡萄糖、苯甲酰芍药苷分别在0.783~50.10、1.094~70.00、2.367~151.5、7.823~500.6、3.125~200.0和0.348~22.25μg/m L内具有良好的线性关系（r2=0.999）,平均回收率分别为102.1%、98.88%、99.25%、100.4%、104.2%、100.6%。结论赤芍和白芍药材样品中芍药内酯苷、1,2,3,4,6-五没食子酰葡萄糖、没食子酸和没食子酸甲酯的量差异较显著,除芍药苷外,单萜苷类成分在白芍中量明显较高,而多元酚类化合物在赤芍特别是川赤芍中量普遍居高。展开更多
基金the Postdoctoral Science Foundation of China,No.1999-10 State Postdoctoral Foundation Commission
文摘AIM: To set up a new method to detect tissue inhibitors of metalloproteinase-1 and -2(TIMP-1 and TIMP-2) in sera of patients with hepatic cirrhosis, and to investigate the expression and location of TIMP-1 and TIMP-2 in liver tissue of patients with hepatic cirrhosis, and the correlation between TIMPs in liver and those in sera so as to discuss whether TIMPs can be used as a diagnosis index of hepatic fibrosis. METHODS: The monoclonal antibodies (McAbs) of TIMP-1 and TIMP-2 were used to sensitize erythrocytes, and solid-phase absorption to sensitized erythrocytes (SPASE) was used to detect TIMP-1 and TIMP-2 in the sera of patients with hepatic cirrhosis. Meanwhile, with the method of in situ hybridization and immunohistochemistry, we studied the mRNA expression and antigen location of TIMP-1 and TIMP-2 in the livers of 40 hepatic cirrhosis patients with pathologic diagnosis. RESULTS: With SPASE, they were 16.4% higher in the acute hepatitis group, 33.3% higher in the chronic hepatitis group, and the positive rates were 73.6% and 61.2% respectively in sera of hepatic cirrhosis patients, which were remarkably higher than those in chronic hepatitis and acute hepatitis group (P【0.001). In 40 samples of hepatic cirrhosis tissues, all of them showed positive expression of TIMP-1 and TIMP-2 mRNA detected with immunohistochemistry or in situ hybridization (positive rate was 100%). Expression of TIMPs in different degrees could be found in liver tissue with cirrhosis. TIMPs were located in cytoplasm of liver cells of patients with hepatic cirrhosis. There was a significant correlation between serum TIMPs level and liver TIMPs level. CONCLUSION: SPASE is a useful method to detect the TIMP-1 and TIMP-2 in sera of patients with hepatic cirrhosis, and TIMP-1 and TIMP-2 can be considered as a useful diagnostic index of hepatic fibrosis, especially TIMP-1.
基金the financial support of Grants CA133791, CA125868, and MH093197 from the National Institutes of Health, United States
文摘The Keap1–Nrf2–ARE pathway is an important antioxidant defense mechanism that protects cells from oxidative stress and the Keap1–Nrf2 protein–protein interaction(PPI) has become an important drug target to upregulate the expression of ARE-controlled cytoprotective oxidative stress response enzymes in the development of therapeutic and preventive agents for a number of diseases and conditions. However, most known Nrf2 activators/ARE inducers are indirect inhibitors of Keap1–Nrf2PPI and they are electrophilic species that act by modifying the sulfhydryl groups of Keap1's cysteine residues. The electrophilicity of these indirect inhibitors may cause "off-target" side effects by reacting with cysteine residues of other important cellular proteins. Efforts have recently been focused on the development of direct inhibitors of Keap1–Nrf2 PPI. This article reviews these recent research efforts including the development of high throughput screening assays, the discovery of peptide and small molecule direct inhibitors, and the biophysical characterization of the binding of these inhibitors to the target Keap1 Kelch domain protein. These non-covalent direct inhibitors of Keap1–Nrf2 PPI could potentially be developed into effective therapeutic or preventive agents for a variety of diseases and conditions.
文摘Biotic and abiotic stress lead to elevated levels of jasmonic acid （JA） and its derivatives and activation of the biosynthesis of nicotine and related pyridine alkaloids in cultivated tobacco （Nicotiana tabacum L.）. Among the JA- responsive genes is NtPMTla, encoding putrescine N-methyl transferase, a key regulatory enzyme in nicotine formation. We have characterized three genes （NtMYC2a, b, c） encoding basic helix-loop-helix （bHLH） transcription factors （TFs） whose expression is rapidly induced by JA and that specifically activate JA-inducible NtPMTla expression by binding a G-box motif within the NtPMTla promoter in in vivo and in vitro assays. Using split-YFP assays, we further show that, in the absence of JA, NtMYC2a and NtMYC2b are present as nuclear complexes with the NtJAZ1 repressor. RNA interference （RNAi）-mediated knockdown of NtMYC2a and NtMYC2b expression results in significant decreases in JA-inducible NtPMTla transcript levels, as well as reduced levels of transcripts encoding other enzymes involved in nicotine and minor alkaloid biosynthesis, in- cluding an 80-90% reduction in the level of transcripts encoding the putative nicotine synthase gene NtA662. In contrast, ectopic overexpression of NtMYC2a and NtMYC2b had no effect on NtPMTla expression in the presence or absence of exogenously added JA. These data suggest that NtMYC2a, b, c are required components of JA-inducible expression of multiple genes in the nicotine biosynthetic pathway and may act additively in the activation of JA responses.
文摘目的建立同时测定赤芍Paeoniae Rubra Radix和白芍Paeoniae Alba Radix中没食子酸、没食子酸甲酯、芍药内酯苷、芍药苷、1,2,3,4,6-五没食子酰葡萄糖、苯甲酰芍药苷的HPLC方法,测定和比较32批不同产地和收集地赤芍和白芍中6种化学成分的量。方法采用HPLC法进行测定,流动相为乙腈-0.1%磷酸水溶液,体积流量0.8 m L/min,柱温30℃,检测波长为230 nm和270 nm。结果结果显示,没食子酸、没食子酸甲酯、芍药内酯苷、芍药苷、1,2,3,4,6-五没食子酰葡萄糖、苯甲酰芍药苷分别在0.783~50.10、1.094~70.00、2.367~151.5、7.823~500.6、3.125~200.0和0.348~22.25μg/m L内具有良好的线性关系（r2=0.999）,平均回收率分别为102.1%、98.88%、99.25%、100.4%、104.2%、100.6%。结论赤芍和白芍药材样品中芍药内酯苷、1,2,3,4,6-五没食子酰葡萄糖、没食子酸和没食子酸甲酯的量差异较显著,除芍药苷外,单萜苷类成分在白芍中量明显较高,而多元酚类化合物在赤芍特别是川赤芍中量普遍居高。
