ABSTRACT
Objective To investigate the role of IQ domain GTPase-activating protein 1 (IQGAP1) in angiotensin Ⅱ (Ang Ⅱ)-induced podocyte apoptosis and the underlying mechanism.Methods Differentiated mouse podocytes were exposed to Ang Ⅱ at different concentrations for 6 h or at 10-8 mol/L for variable incubation time.Podocyte apoptosis was assessed by flow cytometry.Expression of IQGAP1 was analyzed by immunofluorescence and Western blotting.IQGAP1 siRNA and MAPK pathway inhibitors(10 μmol/L SB202190,25 μmol/L SP600125,10 μmol/L U0126) were further introduced to investigate the role of IQGAP1 and MAPK signalings in the process.And coimmunoprecipitation was used to evaluate the interaction between ERK1/2 and IQGAP1.Results (1)Ang]] promoted podocyte apoptosis in a dose-and time-dependent manner.(2) IQGAP1 was located in celluar membrane and cytoplasm of cultured podocytes.Exposure to Ang Ⅱ stimulated IQGAP1expression in a dose-and time-dependent manner,and elevated phosphorylation of p38,JNK,and ERK1/2 simultaneously.(3) Pretreatment with SB202190,SP600125,or U0126 dramatically prevented Ang Ⅱ-promoted podocyte apoptosis respectively (P ＜ 0.05).However,the protein level of IQGAP1 was not altered.(4) Knockdown of IQGAP1 with siRNA obviously prevented Ang]Ⅱ-induced apoptosis of podocytes(P ＜ 0.05) and reduced Ang Ⅱ-induced phosphorylation of ERK1/2(P ＜ 0.05),but not that of p38,JNK.This was accompanied by a reduced interaction between ERK1/2 and IQGAP1(P ＜ 0.05).Conclusion IQGAP1 contributes to Ang Ⅱ-induced podocyte apoptosis by interacting with the ERK1/2 signaling protein.
ABSTRACT
Objective To measure the in vitro antibacterial activity of tigecycline against carbapenems-resistant Acinetobacter calcoacetcus-Acinetobacter baumannii complex.Methods The isolated strains of carbapenems-resistant Acinetobacter calcoacetcus-Acinetobacter baumannii complex were collected in our hospital from December 2013 to February 2014.The MIC test strip was a-dopted to measure the MIC value of tigecycline.The break point adopted the judgment criteria published by FDA.Results All 61 strains of carbapenems-resistant Acinetobacter calcoacetcus-Acinetobacter baumannii complex had extremely high drug resistant rate to the commonly used antimicrobial agents.The sensitive rate of tigecycline was 80.3%,intermediation was 19.7% and no re-sistant strain was found in this study.MIC50 and MIC90 were 2 μg/mL and 3 μg/mL respectively.Conclusion Tigecycline has bet-ter in vitro antibacterial activity to the carbapenems-resistant Acinetobacter calcoacetcus-Acinetobacter baumannii complex isolated in our hospital.
ABSTRACT
Objective To evaluate the effects of Ang Ⅱ on the expression of IQ domain GTPase-activating protein1 (IQGAP1) and apoptosis of glomerular cells,and to explore the role of IQGAP1 in Ang Ⅱ-induced apoptosis of glomerular cells.Methods Thirty-six male Wistar rats were randomly assigned to receive either saline or Ang Ⅱ by osmotic mini-pump,or be used as normal control.The systolic blood pressure and proteinuria were measured at day 7,14,21,28.After the animals were sacrificed at day 14,28 respectively,the kidneys were collected.Renal pathological change,glomerular cell apoptosis were observed.The expression of glomerular IQGAP1 was assessed by immunohistochemistry,immunofluorescence and Western blotting.The activation of caspase-3 and phosphorylation of extracellular regulated protein kinases 1 and 2 (ERK1/2) were determined by Western blotting.Results Ang Ⅱ-infused rats developed significant hypertension and marked proteinuria.Mild glomerular mesangial cell proliferation and mesangial matrix increase were also observed in Ang Ⅱ-infused rats.The number of apoptotic glomerular cells in Ang Ⅱ-infused rats was significantly more than that in normal control (P ＜ 0.05).The expression of IQGAP1 in glomeruli distributed linearly along the capillary loops.Ang Ⅱ infusion up-regulated the expression of glomerular IQGAP1,which had an significantly positive correlation with activation of caspase-3(r =0.689,P ＜ 0.05) and phosphorylation of ERK1/2 (r =0.658,P ＜ 0.05).Conclusion The enhanced expression of IQGAP1 may be involved in Ang Ⅱ-induced glomerular cells apoptosis via activation of ERK1/2 signaling pathway.