Mechanism of sophocarpine in treating experimental colitis in mice / 中国中药杂志

To study the preventive effect of sophocarpine (Soc) on dextran sulfate sodium (DSS)-induced colitis in mice, in order to analyze the influence of Soc on toll like receptor 4 (TLR4)/mitogen-activated protein kinases (MAPKs) and janus tyrosine kinase 2 signal transducer and activator of transcription 3 (JAK2/STAT3) signal pathways in mice intestinal tissues. The mice was given 2.5% DSS for 6 days to induce the acute colitis model. The Soc-treated group was intraperitoneally injected with sophocarpine 30 mg · kg(-1) · d(-1) since the day before the experiment to the end. The disease activity index (DAI) was assessed everyday, and the colonic morphology and histological damage were observed with HE staining. The mRNA expressions of tumor necrosis factor-α (TNF-α), interleukin-1β (IL-1β) and interleukin-6 (IL-6) were detected by real-time RT-PCR. The changes in key protein kinase p38 mitogen-activated protein kinase (p38MAPK), c-Jun NH2-terminal protein kinase1/2 (JNK1/2), extracellular signal-regulated kinase1/2 (ERK1/2), JAK2, STAT3 in TLR4/MAPKs and JAK2/STAT3 signaling pathways were detected by western blot. The result showed that the model group showed statistical significance in body weight, DAI, colon length and histopathological changes compared with the normal group (P <0.05); however, the Soc-treated group showed significant improvements in the above indexes compared with the model group (P <0.05). TNF-α, IL-1β and IL-6 in the model group was significantly higher than that in the normal group (P <0.05), but lowered in the Soc-treated group to varying degrees (P <0.05). In the normal group, the expressions of TLR4 and the phosphorylation of P38, JNK1/2, JAK2, STAT3 were at low levels; in the model group, the phosphorylation of P38, JNK1/2, JAK2, STAT3 increased; the Soc-treated group showed a decrease in TLR4 expression compared with the model group, with notable declines in the phosphorylation of TLR4, P38, JNK1/2, JAK2, STAT3. These findings indicate that Soc can inhibit TLR4/MAPKs, K2/STAT3 signaling pathway activation, reduce the expression of proinflammatory cytokines TNF-α, IL-1β and IL-6 and relieve inflammatory reactions, so as to effectively prevent experimental colitis.

Inhibition of proliferation of hepatic stellate cells by taurine is mediated via regulating cell cycle proteins / 中华肝脏病杂志

<p><b>OBJECTIVE</b>To explore the possible mechanism(s) of taurine-inhibiting the proliferation of hepatic stellate cells (HSC), this study investigated the effect of taurine on the HSC cell cycle and its regulatory protein expression.</p><p><b>METHODS</b>Cell proliferation was assessed by MTT assay. Cell cycle was analyzed by flow cytometry. Cell cycle regulatory protein Cyclin D1 and P21waf1 expression were determined by immunocytochemistry and image-analysis system, and real-time quantitative PCR.</p><p><b>RESULTS</b>HSC proliferation was markedly inhibited when HSC were treated with taurine at concentrations of 5, 10, 20, 30, 40 and 50 mmol/L for 48 hours, and the inhibition rates were 6.7%, 14.4%, 23.3%, 32.2%, 36.7% and 45.6% respectively (P < 0.05-0.01). In the flow cytometry analysis, it was found that taurine could block HSC in the G0/G1 phase from entering the S phase, resulting in more cells in the G0/G1 phase and fewer in the S phase. The percentage of the cells in the G0/G1 phase and the S phase at the dosage of 40 mmol/L were 68.2%+/-1.4% and 26.2+/-1.3% respectively, which was significantly different in comparison to the controls (56.2%+/-1.7% and 38.5%+/-0.8% respectively, P < 0.01). HSC expressed cyclin D1 and P21waf1. Taurine inhibited cyclin D1 expression and induced P21waf1 expression. The cyclin D1 protein and mRNA in the HSC treated with 40 mmol/L taurine were significantly reduced compared with the controls [protein (optical density value): 0.13+/-0.02 versus 0.18+/-0.02, P < 0.01; mRNA: 5776.7+/-3345.0 versus 18,400.6+/-1374.8 copies/10(6) GAPDH, P < 0.01]; and the P21waf1 protein and mRNA were markedly increased compared with the controls [protein (optical density value): 0.19+/-0.02 versus 0.14+/-0.01, P < 0.01; mRNA: 44,866.7+/-3910.7 versus 16,933.3+/-960.9 copies/10(6) GAPDH, P less than 0.05].</p><p><b>CONCLUSIONS</b>Cyclin D1 and P21waf1 were cell cycle regulatory proteins in HSC, and taurine can inhibit the HSC cyclin D1 expression and stimulate P21waf1 expression, facilitate arresting cells in G0/G1 phase, and suppress cell proliferation.</p>

Effects of ribozyme targeting platelet-derived growth factor receptor beta subunit gene on the proliferation and apoptosis of hepatic stellate cells in vitro / 中华医学杂志(英文版)

<p><b>BACKGROUND</b>Activation and proliferation of hepatic stellate cells (HSC) is essentially involved in the development and progression of hepatic fibrosis. The most potent growth factor for HSC is platelet-derived growth factor receptor (PDGF) and PDGF receptor beta subunit (PDGFR-beta) is the predominant signal transduction pathway of PDGF which is overexpressed in activated HSC. This study investigated the cleavage activity of hammerhead ribozyme targeting PDGFR-beta mRNA in HSC and the effect on biological characteristics of HSC.</p><p><b>METHODS</b>Expression vector of anti-PDGFR-beta ribozyme was constructed and transfected into rat activated HSC with lipofectamin. The positive cell clones were gained by G418 selection. The expression of PDGFR-beta, alpha-smooth muscle actin, and typeI and type III collagen were detected by using Northern blot, Western blot and immunocytochemical staining, respectively. The cell proliferation was determined with MTT colorimetric assay. The cell apoptosis was analyzed by using flow cytometry, acridine orange fluorescence vital staining and transmission electron microscopy.</p><p><b>RESULTS</b>The expression of PDGFR-beta at mRNA and protein level was markedly reduced in ribozyme-transfected HSC by 49% - 57% (P < 0.05 - 0.01). The proliferation and alpha-smooth muscle actin expression of ribozyme-transfected HSC were significantly decreased (P < 0.05 - 0.01), and the type I and type III collagen synthesis were also reduced (P < 0.01). In addition, the proliferative response of ribozyme-transfected HSC to PDGF BB was significantly inhibited. Otherwise, the apoptotic cells were significantly increased in ribozyme-transfected HSC (P < 0.01), and typical apoptotic cells could be found under transmission electron microscopy.</p><p><b>CONCLUSIONS</b>The anti-PDGFR-beta ribozyme effectively cleaved the target RNA and significantly inhibited its expression, which blocked the signal transduction of PDGF at receptor level, inhibited HSC proliferation and collagen synthesis, and induced HSC apoptosis. These results suggest that inhibiting PDGFR-beta expression of HSC may be a new target for the therapy of liver fibrogenesis, and ribozyme may be a useful tool for inhibiting PDGFR-beta expression.</p>

The expression of platelet-derived growth factor (PDGF) receptor-beta and its correlation with extracellular matrix in hepatic tissue in hepatic fibrosis rats / 中华肝脏病杂志

<p><b>OBJECTIVE</b>To investigate the expression of PDGF receptor-beta and its correlation with extracellular matrix in hepatic tissue during hepatic fibrosis.</p><p><b>METHODS</b>The model of hepatic fibrosis in rats was induced by carbon tetrachloride. PDGF receptor-beta subunit, collagen I, collagen III and a-SMA in hepatic tissues of these rats were examined using immunohistochemistry. The correlation between PDGF receptor-beta subunit and collagen I, III was analyzed using SAS software after the results of immunohistochemistry were semi-quantified.</p><p><b>RESULTS</b>PDGF receptor-beta subunit and a-SMA were not detected in normal controls. Collagen I and III were distributed in the portal tracts and beneath the endothelia of the central veins and of the Disse spaces. Two weeks after CCl4 injection, the PDGF receptor-beta and a-SMA were detected, and the expression of collagen I and III increased. At the end of 4 and 6 weeks, the above four proteins were further increased. Two weeks after CCl4 injection, PDGF receptor-beta had no apparent correlation with collagen I and III. However, PDGF receptor-beta had a significant correlation with collagen I and III 2 weeks later, and the correlation coefficient was 0.74 and 0.60 respectively at 4 weeks, and 0.83 and 0.67 respectively at 6 weeks. PDGF receptor-beta had a significant correlation with a-SMA during the whole process of hepatic fibrosis and the correlation coefficient was 0.62, 0.69 and 0.81, respectively at the time of 2, 4 and 6 weeks after CCl4 injection.</p><p><b>CONCLUSION</b>The PDGF receptor-beta was overexpressed during the process of hepatic fibrosis development, and it significantly correlated with collagen I and collagen III.</p>

Proliferation of hepatocytes after delivery of exogenous hepatocyte growth factor gene / 中华肝脏病杂志

<p><b>OBJECTIVE</b>To explore the proliferation of primary cultured rats hepatocytes after delivery of exogenous hepatocyte growth factor (HGF) gene which was inserted into the genome of replication-deficient recombinant adenovirus vector.</p><p><b>METHODS</b>The recombinant adenovirus-AdHGF which could express HGF was generated by homologous recombination. After the HGF gene was delivered into the hepatocytes, the expression of both HGF and c-met/HGF receptor mRNA in the cells was detected by RT-PCR and the level of HGF in the culture supernatant was also assayed by ELISA. On the other hand, cell proliferation was compared between before and after delivery of the HGF gene by MTS assay and the percentages of cell cycles were analyzed by flow cytometry. In addition, the expression of proliferating cell nuclear antigen (PCNA) was determined by immunocytofluorescent stain.</p><p><b>RESULTS</b>4 x 10(10) efu/ml titer of AdHGF was obtained after recombination, RT-PCR indicated that the expression of HGF mRNA in hepatocytes increased on the third day after infected by the viruses and c-met/HGF receptor mRNA was also up-regulated. The HGF level in the culture supernatant assayed by ELISA was (5,939.0+/-414.39) pg/ml, which was much higher than that in the control (208.1pg/ml+/-37.20pg/ml, F=13.661, P<0.01). In addition, the proliferation of hepatocytes infected with AdHGF increased significantly according to MTS method (F>or=15.158, P<0.01) and more hepatocytes in G0/G1 stages changed into S stage (chi2=41.616, P<0.01), accordingly, PCNA index increased from 6.42+/- 1.88 to 14.56+/-2.85 (F=42.122, P<0.01).</p><p><b></b>CONCLUSION</p><p><b>THE RESULTS</b>show that HGF gene delivered into hepatocytes by AdHGF can be expressed with high efficiency in the cells, which can stimulate hepatocytes proliferation. It may be an effective tool for hepatocyte transplantation by gene modified donor hepatocytes.</p>

Effect of ribozyme against platelet-derived growth factor receptor beta subunit mRNA on the biological characters of hepatic stellate cells / 中华肝脏病杂志

<p><b>OBJECTIVE</b>To study the cleavage activity of hammerhead ribozyme targeting at platelet-derived growth factor receptor beta subunit (PDGFR- beta) mRNA in hepatic stellate cells (HSCs) and its effect on the biological characters of HSCs.</p><p><b>METHODS</b>Expression vector of anti-PDGFR- beta ribozyme was constructed and transfected into rat-derived HSC-T6 cells with lipofectin. The positive cell clones were gained by G418 selection. The expression of PDGFR- beta, alpha-smooth muscle actin (alpha-SMA), and type I and type III collagen was detected by means of northern blot, Western blot and immunocytochemical staining respectively. The cell proliferation was determined with MTT colorimetric assay. The cell apoptosis was demonstrated with flow cytometry, acridine orange fluorescence vital staining and transmission electron microscopy.</p><p><b>RESULTS</b>The expression of PDGFR- beta at mRNA and protein level was markedly reduced in ribozyme-transfected HSCs only 43% to 51% of that in control cells (t > or = 3.957, P < 0.05), and alpha-SMA expression level, type I and type III collagen synthesis ability were also reduced (t > or = 6.790, P < 0.01). The proliferation of ribozyme-transfected HSCs was significantly decreased (t > or = 3.858, P < 0.05), and the proliferation response to PDGF BB was markedly inhibited. However the apoptotic rate was significantly increased in ribozyme-transfected HSCs (chi2 > or = 14.157, P < 0.01), and typical apoptotic cells could be found under transmission electron microscopy.</p><p><b>CONCLUSIONS</b>The anti-PDGFR- beta ribozyme can be expressed stably in HSCs, cleave the target RNA effectively, inhibit HSCs proliferation and collagen synthesis, and induce HSC apoptosis. The results suggest that inhibiting PDGFR- beta expression in HSCs may be a new therapy for liver fibrosis.</p>