Publications (6)14.06 Total impact
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Article: [Screening for inhibitor of vascular endothelial growth factor from random peptide library].
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ABSTRACT: To screen for the inhibitor of vascular endothelial growth factor (VEGF) 165 from random peptide library. Positive phage clones were rescued after two rounds of panning and competitive elution. Its affinity activity to KDR was monitored through ELISA, immunohistochemical method, Chicken CAM assay and MTT. Five specific binding positive target molecule phage clones were obtained which were able to bind to cells whose surface had high KDR, among which, clone 3 and 13 could effectively block the vascularization of the chorioallantoic membrane of chick embryo, but they were not inhibitive on the proliferation of high KDR expression cells. The peptides, being the inhibitors of VEGF, may be useful in the treatment of cancers.Zhonghua zhong liu za zhi [Chinese journal of oncology] 12/2002; 24(6):540-3. -
Article: Identification of hepatopoietin dimerization, its interacting regions and alternative splicing of its transcription.
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ABSTRACT: Hepatopoietin (HPO) is a novel human hepatotrophic growth factor. Recently, we demonstrated that the extracellular ligand form of HPO can stimulate proliferation of hepatic cells via its specific receptor, which is on the surface of these cells. Also, the intracellular form of HPO potentiates the transcriptional factor AP-1. Intriguingly, a variety of HPO complexes with different molecular masses were detected in hepatocytes. In this study, we screened a human fetal liver cDNA library using the yeast two hybrid system with HPO as bait, hoping to find an HPO-binding protein. Surprisingly, HPO, itself, and a previously unidentified alternatively spliced form of HPO (named HPO23) were identified as interacting with HPO, indicating that HPO may exist as a homodimer or heterodimer. These results were further confirmed in vitro and in vivo. First, mass spectrometry analysis demonstrated that recombinant human HPO exist as a homodimer and that disulfide bonds were involved in the formation of rhHPO dimer. Secondly, a pull-down experiment confirmed that GST-HPO and HA-HPO, could bind together in vitro. Using HPO and various HPO deletion mutants, we identified the extreme 30 amino acids at both N- and C-termini are essential for HPO dimerization. Finally, Western blotting analysis demonstrated that HPO exists as two isoforms at 15 kDa and 23 kDa (HPO23) in liver cells, the 15 kDa species is located in nucleus, and the 23 kDa species mainly in the cytoplasm. These results implicated that the capacity of HPO to form both homodimers and heterodimers with the alternatively spliced forms might contribute to the existence of various HPO complexes in hepatic cells.European Journal of Biochemistry 09/2002; 269(16):3888-93. · 3.58 Impact Factor -
Article: Identification of hepatopoietin dimerization, its interacting regions and alternative splicing of its transcription
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ABSTRACT: Hepatopoietin (HPO) is a novel human hepatotrophic growth factor. Recently, we demonstrated that the extracellular ligand form of HPO can stimulate proliferation of hepatic cells via its specific receptor, which is on the surface of these cells. Also, the intracellular form of HPO potentiates the transcriptional factor AP-1. Intriguingly, a variety of HPO complexes with different molecular masses were detected in hepatocytes. In this study, we screened a human fetal liver cDNA library using the yeast two hybrid system with HPO as bait, hoping to find an HPO-binding protein. Surprisingly, HPO, itself, and a previously unidentified alternatively spliced form of HPO (named HPO23) were identified as interacting with HPO, indicating that HPO may exist as a homodimer or heterodimer. These results were further confirmed in vitro and in vivo. First, mass spectrometry analysis demonstrated that recombinant human HPO exist as a homodimer and that disulfide bonds were involved in the formation of rhHPO dimer. Secondly, a pull-down experiment confirmed that GST–HPO and HA–HPO, could bind together in vitro. Using HPO and various HPO deletion mutants, we identified the extreme 30 amino acids at both N- and C-termini are essential for HPO dimerization. Finally, Western blotting analysis demonstrated that HPO exists as two isoforms at 15 kDa and 23 kDa (HPO23) in liver cells, the 15 kDa species is located in nucleus, and the 23 kDa species mainly in the cytoplasm. These results implicated that the capacity of HPO to form both homodimers and heterodimers with the alternatively spliced forms might contribute to the existence of various HPO complexes in hepatic cells.European Journal of Biochemistry. 07/2002; 269(16):3888 - 3893. -
Article: [Effect of recombinant human augmenter of liver regeneration on gene expression of tissue inhibitor of metalloproteinase-1 in rat with experimental liver fibrosis].
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ABSTRACT: To investigate the influence of recombinant human augmenter of liver regeneration (hALR) on gene expression of tissue inhibitor of metalloproteinase-1 (TIMP1) in rat with experimental liver fibrosis. Carbon tetrachloride was injected into the peritoneal cavities of 150 rats twice a week for 8 weeks. Albumin sensitization and caudal vein attack were conducted to another 136 rats for the duration of 3.5 months, so as to establish two kinds of animal model of experimental liver fibrosis. Recombinant hALR at different doses was given during the process of model making. Specimens of liver were taken at different time-points, then the total RNA of liver tissues was isolated and TIMP1 gene expression levels were measured by reverse transcription polymerase chain reaction. In both rat models, TIMP(1) gene expression levels increased gradually during the process of model making. The TIMP(1) gene expression level in CCl4 model treated with low dose hALR was 0.86 +/- 0.13, 1.77 +/- 0.23, 2.78 +/- 0.36, and 3.76 +/- 0.50 respectively 2, 4, 6, and 8 weeks after the beginning of model making, all lower than those in the model group, however, without significant difference. The TIMP(1) gene expression level in CCl4 model treated with high dose hALR was 0.63 +/- 0.10, 1.18 +/- 0.20, 1.89 +/- 0.30, 2.63 +/- 0.33 respectively 2, 4, 6, and 8 weeks after the beginning of model making, significantly lower than those in CCl4 model treated with low dose hALR. In the albumin model group the TIMP(1) gene expression level showed no change during albumin sensitization, significantly increased during caudal vein attack, and reached the peak after medel making. The TIMP(1) gene expression level was lower in albumin model treated with low dose hALR during and after caudal vein attack than in the model group and negative control group, however, without significant difference (both P > 0.05). The TIMP(1) gene expression level in albumin model treated with high dose hALR was 2.33 +/- 0.36 and 4.02 +/- 0.53 during and after caudal vein attack respectively, significantly lower than those in CCl4 model group (0.99 +/- 0.14, 2.03 +/- 0.30, 2.99 +/- 0.43, and 4.13 +/- 0.44 respectively 2, 4, 6, and 8 weeks after beginning of model making respectively) and those in albumin model without hALR treatment and that with low dose hALR (4.13 +/- 0.60 and 5.99 +/- 0.83, and 3.70 +/- 0.82 and 5.63 +/- 0.89 during and after caudal vein attack respectively), and negative control group. High dose recombinant human augmenter of liver regeneration is effective in inhibiting gene expression of TIMP(1) in experimental liver fibrosis.Zhonghua yi xue za zhi 05/2002; 82(9):610-2. -
Article: Intracrine hepatopoietin potentiates AP-1 activity through JAB1 independent of MAPK pathway.
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ABSTRACT: Many growth factors and cytokines are involved in liver regeneration. Of them, only hepatopoietin (HPO)/ALR (augmenter of liver regeneration) is a specifically hepatotrophic factor originally identified from the cytosol of regenerating or hyperplastic hepatic cells. Previous reports indicate that extracellular HPO triggers the MAPK pathway by binding its specific receptor on the cell surface. However, its function in the cytosol of hepatocytes is unclear. Here we identified that JAB1 (Jun activation domain-binding protein 1), a co-activator of AP-1, which is essential for liver regeneration, specifically interacts with intracellular HPO. JAB1 colocalizes with HPO in nuclei of hepatic cells or COS-7 cells. As an intracrine factor, the intracellular function of HPO is to increase c-Jun phosphorylation independent of c-Jun amino-terminal kinase (JNK), extracellular signal-regulated kinase (ERK) -1 and -2, and leads to potentiation of JAB1-mediated AP-1 activation. Amino acids 1-63 of HPO molecule are sufficient to bind to JAB1, but the full-length HPO is necessary for its intracellular signaling. Taken together, these results elucidate a novel mechanism of intracrine cytokine signaling by specifically modulating the AP-1 pathway through JAB1, in a MAPK-independent fashion.The FASEB Journal 02/2002; 16(1):90-2. · 5.71 Impact Factor -
Article: Stimulation of the Mitogen-activated Protein Kinase Cascade and Tyrosine Phosphorylation of the Epidermal Growth Factor Receptor by Hepatopoietin
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ABSTRACT: Hepatopoietin (HPO) is a novel human hepatotrophic growth factor, which specifically stimulates proliferation of cultured primary hepatocytes in vitro and liver regeneration after liver partial hepatectomy in vivo. Recently, the identification of the mitogenic effect of HPO on hepatoma cell lines and the existence of HPO-specific receptors indicate that HPO acts via its specific cell surface receptor. However, the molecular mechanism of HPO action is not fully elucidated. In this report, we examined the signal transduction events induced by HPO in hepatoma cell line (HepG2). Our results demonstrated that HPO induces phosphorylation of mitogen-activated protein kinase kinase and mitogen-activated protein kinase (MAPK) in a rapid and transient manner. HPO stimulates tyrosine phosphorylation of epidermal growth factor receptor (EGFR). Furthermore, we observed that both MAPK activation and the mitogenic effect of HPO on HepG2 cells were completely blocked by AG1478, a specific inhibitor of EGFR tyrosine kinase activity. However, the effects of HPO were not antagonized by an EGFR-blocking antibody, mAb528, which blocks the interaction between epidermal growth factor and EGFR, indicating that stimulation of tyrosine phosphorylation of EGFR by HPO was not mediated by epidermal growth factor. In contrast, genistein, a general tyrosine kinase inhibitor, significantly attenuated the tyrosine phosphorylation of EGFR in response to HPO. In conclusion, our results suggest that tyrosine phosphorylation of EGFR may play a critical role in MAPK activation and mitogenic stimulation by HPO.Journal of Biological Chemistry 11/2000; 275(48):37443-37447. · 4.77 Impact Factor
Top Journals
Institutions
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2002
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301 Military Hospital
Beijing, Beijing Shi, China -
Chinese National Human Genome Center at Shanghai
Shanghai, Shanghai Shi, China -
307 Hospital of the Chinese People's Liberation Army
Beijing, Beijing Shi, China
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