Endoplasmic Reticulum Stress-mediated Aldosterone-induced Apoptosis in Vascular Endothelial Cells

The aim of this study was to examine the effects of endoplasmic reticulum （ER） stress on aldosterone （Aldo）-induced apoptosis of endothelial cells. Glucose-regulated protein 78 （GRP78） and C/EBP homologous protein （CHOP, a hallmark of ER-associated apoptosis） were used to evaluate ER stress. Western blotting and real-time PCR were used to analyze indicators of ER molecule. Apoptosis was detected by annexin V/propidium iodide staining and flow cytometry. Human umbilical vein endo- thelial cells （HUVECs） were stimulated with different concentrations of Aldo for different durations. Aldo promoted apoptosis of HUVECs and induced ER stress, as evidenced by increased expression of GRP78 and CHOP. siRNA knockdown of CHOP attenuated Aldo-mediated apoptosis. These results in- dicate that ER stress may be involved in Aldo-induced apoptosis of HUVECs.     

Effects of lead exposure on placental cellular apoptosis and endoplasmic reticulum stress in rats

Background Lead exposure during pregnancy contributes to fetal abortion and/or teratogenesis.Endoplasmic reticulum （ER） apoptosis can be induced by various pathological conditions when ER function is disturbed.However,it is unclear whether ER stress and apoptosis play a role in the etiology of lead-exposed disease status.We aimed to investigate whether lead induced placental apoptosis and subsequent toxicity is initiated by ER apoptosis via caspase-12.Methods Sixty-three female Wistar rats were exposed to lead in drinking water during various gestational periods.Blood lead level was determined by atomic absorption spectrophotometry.Placental cytoplasmic organelles were examined by electronic microscopy.Placental caspase-12 mRNA expression was evaluated by qRT-PCR.TUNEL assay was used to determine the placental apoptosis.Results Lead exposure significant induced ER apoptosis compared to that of the controls （P ＜0.05）,accompanied with increased caspase-12 mRNA expression.Significant differences of caspase-12 mRNA expression levels were observed among the four groups （F=13.78,P ＜0.05）.Apoptotic index （AI） was significantly increased in experimental groups compared to that of the controls （F=96.15,P ＜0.05）.In lead-exposed groups,trophoblast cells underwent degeneration and fibrin deposition; Mitochondria were swollen and decreased in number; ER swelling,expansion,and vacuolization were observed.Conclusion Lead exposure contributes to placental apoptosis,as well as increased caspase-12 mRNA expression,which in turn promoted ER stress.     

Dexamethasone protects airway epithelial cell line NCI-H292 against lipopolysaccharide induced endoplasmic reticulum stress and apoptosis

Background  Endoplasmic reticulum (ER) stress and ER stress-mediated apoptosis were reported to be involved in the pathogenesis of several diseases. In a recent study, it was reported that the ER stress pathway was activated in the lungs of lipopolysaccharide (LPS)-treated mice. It was also found that the C/EBP homologous protein (CHOP), an apoptosis-related molecule, played a key role in LPS-induced lung damage. The aim of this study was to verify whether LPS could activate the ER stress response in airway epithelial cells and which molecule was involved in the pathway. This study was also aimed at finding new reagents to protect the airway epithelial cells during LPS injury.

Methods  ER stress markers were observed in LPS-incubated NCI-H292 cells. SiRNA-MUC5AC was transfected into NCI-H292 cells. The effects of dexamethasone and erythromycin were observed in LPS-induced NCI-H292 cells.

Results  LPS incubation increased the expression of ER stress markers at the protein and mRNA levels. The knockout of MUC5AC in cells attenuated the increase in ER stress markers after incubation with LPS. Dexamethasone and erythromycin decreased caspase-3 activity in LPS-induced NCI-H292 cells.

Conclusions  LPS may activate ER stress through the overexpression of MUC5AC. Dexamethasone may protect human airway epithelial cells against ER stress-related apoptosis by attenuating the overload of MUC5AC.

     

Expression of endoplasmic reticulum molecular chaperon GRP94 in human lung cancer tissues and its clinical significance

Objective To investigate the relationship between the expression of glucose regulated protein 94 (GRP94) at the level of mRNA and protein in vivo and in human lung cancer. Methods RT-PCR, immunohistochemistry and/or Western blot were used in 54 cases of lung cancer tissues and corresponding normal lung tissues.Results There was a significant overexpression of GRP94 mRNA and protein in lung cancer tissues as compared with lung normal tissues.In lung cancer tissue, the relative level of GRP94 mRNA as evaluated by RT-PCR was 3.48±2.06, the level of GRP94 protein as evaluated by immunohistochemistry was ++ to +++, and by Western blot was 256.7±80.6.In lung normal tissue, the relative level of GRP94 mRNA was 2.01±1.83, the level of GRP94 protein was + to ++ and 108.1±42.3.The differences in expression of GRP94 between the two tissues were significant ( P <0.05).Furthermore, the over-expression of GRP94 in the lung cancer tissues was correlated to grade of differentiation and stage of tumors.There was stronger expression in poor-differentiated tumors than in mild-to-high differentiated tumors ( P <0.05).There was also a stronger expression in stage Ⅲ than in stage Ⅰ and Ⅱ tumors ( P <0.05).No statistically significant difference was found among various pathological types of tumors. Conclusion GRP94 was related with the occurrence, differentiation and progress of human lung cancer.Ascertaining the levels of GRP94 mRNA and protein may be valuable in evaluating the grade of differentiation and clinical stage of human lung cancer.     

Blocking Ihh signaling pathway inhibits the proliferation and promotes the apoptosis of PSCs

Summary： The roles of Indian hedgehog （Ihh） signaling pathway in the proliferation and apoptosis of precartilaginous stem cells （PSCs） were investigated. PSCs, labeled with fibroblast growth factor receptor 3 （FGFR-3）, were isolated from neonatal rats by immunomagnetic separation. After identification with FGFR-3 and Col II, the cells were incubated with different concentrations of cyclopamine （cyclo）, the specific inhibitor of Ihh signaling pathway. The morphologic changes of the cells were observed under the inverted phase contrast microscope. The mRNA expression levels of Ihh, parathyroid hormonerelated peptide （PTHrP）, protein Patched （Ptch）, Bcl-2 and p21 were detected by RT-PCR. The protein expression levels of Ihh and Ptch were measured by Western blot. MTT assay was used to examine the effects of cyclo on proliferation of PSCs. Apoptosis rate of PSCs was examined by AnnexinV/PI assay of flow cytometric analyses. After PSCs were incubated with cyclo, obvious morphologic changes were observed as compared with the control group. The mRNA expression levels of PTHrP, Ptch and Bcl-2 were decreased to varying degrees in a cyclo dose-dependent manner. However, the expression levels of Ihh and p21 mRNA were increased. The protein expression of Ptch and Ihh had the same change as the mRNA expression. Meanwhile, cyclo could obvi- ously inhibit the proliferation and promote the apoptosis of PSCs. The results indicated that Ihh signaling pathway plays an important role in regulating the proliferation and apoptosis of PSCs, which is probably mediated by Bcl-2 and p21.     

Involvement of the Mitochondrion-dependent and the Endoplasmic Reticulum Stress-signaling Pathways in Isoliquiritigenin-induced Apoptosis of HeLa Cell

Objective Isoliquiritigenin(ISL),a licorice chalconoid,is considered to be a bioactive agent with chemopreventive potential.This study investigates the mechanisms involved in ISL-induced apoptosis in human cervical carcinoma HeLa cells.Methods Cell viability was evaluated using a 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl-tetrazolium bromide(MTT)assay.Apoptosis was determined by flow cytometry using an Annexin V-FITC Apoptosis Detection Kit.The intracellular ROS levels were assessed using a 2,7-dichlorofluorescein probe assay.The mitochondrial membrane potential was measured with the dual-emission potential-sensitive probe 5,5’,6,6’-tetra-chloro-1,1’,3,3’-tetraethyl-imidacarbocyanine iodide(JC-1).The degradation of poly-ADP-ribose polymerase(PARP)protein,the phosphorylation of PKR-like ER kinase(PERK),the phosphorylation of the α-subunit of eukaryotic initiation factor 2(eIF2α),the expression of the 78 kD glucose-regulated protein(GRP 78),and the activation of caspase-12 were analyzed via western blot analysis.Results ISL significantly inhibited the proliferation,the increase in ROS levels and apoptotic rates of HeLa cells in a concentration-dependent manner.Moreover,ISL induced mitochondrial dysfunction,caspase activation,and PARP cleavage,which displayed features of mitochondria dependent on apoptotic signals.Besides,exposure of HeLa cells to ISL triggered endoplasmic reticulum(ER)stress,as indicated by the increase in p-eIF2α and GRP78 expression,ER stress-dependent apoptosis is caused by the activation of ER-specific caspase-12.Conclusion The findings from our study suggest that ISL-induced oxidative stress causes HeLa cell apoptosis via the mitochondrion-dependent and the ER stress-triggered signaling pathways.     

GRP78 upregulation-induced increase in cisplatin sensitivity of SPCA1 lung cancer cells

Background  Glucose regulated protein 78 (GRP78), an endoplasmic reticulum (ER) chaperone, plays a critical role in chemotherapy resistance in a variety of cancers. In this study, we investigated the up-regulation of GRP78 induced by A23187 and its association with the chemotherapeutical sensibility to cisplatin in human lung cancer cell line SPCA1.

Methods  SPCA1 cells were pretreated with A23187 at different concentrations. The expression of GRP78 at the mRNA level was analyzed by RT-PCR; the expression of GRP78 at the protein level was determined by Western blotting and immunofluorescence assay. Cell survival was determined by MTT assay. Cell apoptosis was analyzed by flow cytometry.

Results  The expression of GRP78 at both the mRNA and protein levels was obviously induced by A23187 in SPCA1 cells, with an elevation of GRP78 by 2.1-fold at the mRNA level and by 3.8-fold at the protein level compared to the control. There was a dose-dependent response. Survival curve analysis demonstrated that A23187 induction caused a significant reduction of survival for the cells subjected to cisplatin treatment (P <0.05). After treatment by cisplatin, the percentage of apoptotic cells in the A23187 pretreated group increased about three fold compared with the control group ((27.53±4.32)% vs. (9.25±3.64)%, P <0.05).

Conclusions  A23187 treatment was fairly effective for the induction of GRP78 in SPCA1 cells at both the mRNA and protein levels. To a certain extent, GRP78 up-regulation by A23187 was associated with the enhancement of drug sensitivity to cisplatin in human lung cancer cell line SPCA1.

     

Endoplasmic reticulum stress is involved in podocyte apoptosis induced by saturated fatty acid palmitate

Background  Podocyte apoptosis is recently indicated as an early phenomenon of diabetic nephropathy. Pancreatic b-cells exposed to saturated free fatty acid palmitate undergo irreversible endoplasmic reticulum (ER) stress and consequent apoptosis, contributing to the onset of diabetes. We hypothesized that palmitate could induce podocyte apoptosis via ER stress, which initiates or aggravates proteinuria in diabetic nephropathy.

Methods  Podocyte apoptosis was detected by 4¢,6-diamidio-2-phenylindole (DAPI) stained apoptotic cell count and Annexin V-PI stain. The expressions of ER molecule chaperone glucose-regulated protein 78 (GRP78), indicators of ER-associated apoptosis C/EBP homologous protein (CHOP), and Bcl-2 were assayed by Western blotting and real-time PCR. GRP78 and synaptopodin were co-localized by immunofluorescence stain.

Results  Palmitate significantly increased the percentage of cultured apoptotic murine podocytes time-dependently when loading 0.75 mmol/L (10 hours, 13 hours, and 15 hours compared with 0 hour, P <0.001) and dose-dependently when loading palmitate ranging from 0.25 to 1.00 mmol/L for 15 hours (compared to control, P <0.001). Palmitate time-dependently and dose-dependently increased the protein expression of GRP78 and CHOP, and decreased that of Bcl-2. Palmitate loading ranging from 0.5 to 1.0 mmol/L for 12 hours significantly increased mRNA of GRP78 and CHOP, and decreased that of Bcl-2 compared to control (P <0.001), with the maximum concentration being 0.75 mmol/L. Palmitate 0.5 mmol/L loading for 3 hours, 8 hours, and 12 hours significantly increased mRNA of GRP78 and CHOP, and decreased that of Bcl-2 compared to 0 hour (P <0.001), with the maximum effect at 3 hours. Confocal microscopy demonstrated that GRP78 expression was significantly increased when exposed to 0.5 mmol/L of palmitate for 8 hours compared to control.

Conclusion  Palmitate could induce podocyte apoptosis via ER stress, suggesting podocyte apoptosis and consequent proteinuria caused by lipotoxic free fatty acid could be ameliorated by relief of ER stress.

     

Fibroblast growth factor 21 as a possible endogenous factor inhibits apoptosis in cardiac endothelial cells

Background Fibroblast growth factor 21 (FGF21) is a new member of FGF super family that is an important endogenous regulator for systemic glucose and lipid metabolism. This study aimed to explore whether FGF21 reduces atherosclerotic injury and prevents endothelial dysfunction as an independent protection factor.Methods The present study was designed to investigate the changes of FGF21 levels induced by oxidized-low density lipoprotein (ox-LDL), and the changes of apoptosis affected by regulating FGF21 expression. The FGF21 mRNA levels of cultured cardiac microvascular endothelial cells (CMECs) were determined by real time-PCR and the protein concentration in culture media was detected by enzyme-linked immunosorbent assay. We analyzed the different expression levels of untreated controls and CMFCs incubated with ox-LDL, and the changes of CMECs apoptosis initiated by the enhancement or suppression of FGF21 levels.Results The secretion levels of FGF21 mRNA and protein were significantly upregulated in CMECs incubated with ox-LDL. Furthermore, FGF21 levels increased by 200 μmol/L bezafibrate could reduce CMECs apoptosis, and inhibit FGF21 expression by shRNA induced apoptosis (P ＜0.05).Conclusions FGF21 may be a signal of injured target tissue, and may play physiological roles in improving the endothelial function at an early stage of atherosclerosis and in stopping the development of coronary heart disease.     

Antidepressant-Like Effects of Chaihu Shugan Powder (柴胡疏肝散) on Rats Exposed to Chronic Unpredictable Mild Stress through Inhibition of Endoplasmic Reticulum Stress-Induced Apoptosis

Objective: To investigate the antidepressant-like effects of Chaihu Shugan Powder (CSP, 柴胡疏肝散) and to explore its underlying mechanisms. Methods: Thirty-two Sprague-Dawley rats were randomly divided into control (CON), chronic unpredictable mild stress (CUMS), fluoxetine (FLU), and CSP groups, 8 rats in each group. All of the rats except for those in the control group were subjected to 3 consecutive weeks of CUMS to establish the depression model. The open field test (OFT), forced swimming test (FST), and sucrose preference test were used to assess the anti-anxiety and antidepressant effects of CSP. Terminal deoxynucleotidyl transferase (TdT) dUTP nick-end labeling was used to determine the apoptosis rate in the hippocampal tissues. The mRNA and protein levels of glucose-regulated protein (GRP) 78, spliced X-box-binding protein (XBP)-1, CCAAT/enhancer binding protein homologous protein (CHOP), caspase-12, and c-Jun N-terminal kinase (JNK) in the hippocampus of rats were evaluated by real-time PCR and Western blot analysis, respectively. Results: Administration of CSP alleviated anxiety and depression-like behavior in CUMS rats, as revealed by enhanced time and distance in the center of the OFT (P<0.05), an increased preference for sucrose, and longer swimming time and shorter immobility time during the FST (all P<0.05). In addition, CSP treatment significantly reduced the rate of apoptosis in rat hippocampal neurons (P<0.05). The mRNA and protein expression levels of GRP78, spliced XBP-1, and CHOP were down-regulated along with the expression of caspase-12 and cleaved caspase-12 proteins (all P<0.05), whereas total and phosphorylated JNK1 protein levels did not differ significantly between control and CSP-treated rats. Conclusion: CSP can improve depression-like behavior in rats exposed to CUMS, possibly by suppressing CHOP and caspase-12 mediated apoptosis in the rat hippocampus.     

Fibroblast growth factor 21 as a possible endogenous factor inhibits apoptosis in cardiac endothelial cells

Background Fibroblast growth factor 21 （FGF21） is a new member of FGF super family that is an important endogenous regulator for systemic glucose and lipid metabolism. This study aimed to explore whether FGF21 reduces atherosclerotic injury and prevents endothelial dysfunction as an independent protection factor.Methods The present study was designed to investigate the changes of FGF21 levels induced by oxidized-low density lipoprotein （ox-LDL）, and the changes of apoptosis affected by regulating FGF21 expression. The FGF21 mRNA levels of cultured cardiac microvascular endothelial cells （CMECs） were determined by real time-PCR and the protein concentration in culture media was detected by enzyme-linked immunosorbent assay. We analyzed the different expression levels of untreated controls and CMFCs incubated with ox-LDL, and the changes of CMECs apoptosis initiated by the enhancement or suppression of FGF21 levels.Results The secretion levels of FGF21 mRNA and protein were significantly upregulated in CMECs incubated with ox-LDL. Furthermore, FGF21 levels increased by 200 μmol/L bezafibrate could reduce CMECs apoptosis, and inhibit FGF21 expression by shRNA induced apoptosis （P ＜0.05）.Conclusions FGF21 may be a signal of injured target tissue, and may play physiological roles in improving the endothelial function at an early stage of atherosclerosis and in stopping the development of coronary heart disease.     

Influence of silencing soluble epoxide hydrolase with RNA interference on cardiomyocytes apoptosis induced by doxorubicin

In order to investigate the influence of silencing soluble epoxide hydrolase(sEH) with double-stranded small interfering RNA(siRNA) on cardiomyocytes apoptosis induced by doxorubicin(DOX),two plasmids containing siRNA sequences specific to sEH were constructed and transfected into the primary cultured cardiomyocytes by using FuGENE HD transfection agents.The mRNA and protein expression levels of sEH were detected by semiquantitative RT-PCR and Western blotting respectively,and the plasmids that silenced sEH most significantly were selected,and renamed EH-R.The plasmids carrying a nonspecific siRNA coding sequence(PCN) served as the negative control.Cardiomyocytes were divided into four groups:control group,DOX group,PCN+DOX group,and EH-R+DOX group.Apoptosis of cardiomyocytes was induced by DOX at a concentration of 1 μmol/L.Apoptosis rate of cardiomyocytes was determined by flow cytometery.The protein expression levels of Bcl-2 and Bax were detected by Western blotting.The results showed that the expression of sEH was down-regulated by EH-R plasmid.The expression levels of sEH mRNA and protein in the EH-R+DOX group were significantly decreased as compared with other groups(P<0.01).As compared with the control group,the apoptosis rate of cardiomyocytes in three DOX-treated groups was obviously increased,the expression levels of Bax increased,and those of Bcl-2 decreased(P<0.01).However,the expression levels of Bax were decreased,those of Bcl-2 increased and the apoptosis rate of cardiomyocytes obvi-ously decreased in EH-R+DOX group when compared with those in the DOX group and the PCN+DOX group(P<0.01 for each).It was concluded that the recombinant plasmids could be successfully constructed,and transfected into the primary cultured cardiomyocytes.They could ameliorate the DOX-induced cardiomyocytes apoptosis by selectively inhibiting the expression of sEH with RNAi and increasing the expression of Bcl-2.     

MDR1 and MDR3 Genes and Drug Resistance to Cisplatin of Ovarian Cancer Cells

To investigate the relationship between MDR1 and MDR3 gene and drug resistance to cisplatin of ovarian cancer cells. Two siRNAs (MDR1, MDR3) which specifically targeted MDR1 and MDR3 genes were transfered into A2780/DDP cells. Then double staining with Annexin- V-FITC/PI was used to detect cell apoptosis by the flow cytometry (FCM). A2780/DDP cell viability was determined by MTT. MDR1 and MDR3 mRNA were assessed by RT-PCR. Caspase-3 protein was detected by Western blotting. Transfection of MDR1 and MDR3 siRNA into A2780/DDP cells failed to reverse the drug-resistance of A2780/DDP cells to cisplatin (P>0.05). No significant differ- ence in the apoptosis efficiency was observed between the MDR1 and MDR3 siRNA, pSuppressor- Neo vector transfection cells and untreated cells (P>0.05). In the presence of cisplatin of different concentrations, the viability of A2780/DDP cells was not significantly decreased after the transfection. No changes in MDR1 and MDR3 mRNA were found in MDR1 and MDR3 siRNA-transfected A2780/DDP cells. As compared with pSuppressorNeo and untreated groups, no significant difference existed in the expression of MDR1 and MDR3 mRNA (P>0.05). The expression of caspase-3 protein in MDR1 and MDR3 siRNA transfected A2780/DDP cells was not significantly increased. It is con- cluded that multidrug resistance induced by cisplatin in ovarian carcinoma cell lines is not due to overexpression of MDR1 and MDR3 gene. The drug resistance of ovarian carcinoma cells to cisplatin is not mediated by P-glycoprotein.     

Visfatin Protects Rat Pancreatic β-cells against IFN-γ-Induced Apoptosis through AMPK and ERK1/2 Signaling Pathways

ObjectiveInterferon-γ (IFN-γ) plays an important role in apoptosis and was shown to increase the risk of diabetes.Visfatin, an adipokine, has anti-diabetic, anti-tumor, and regulating inflammatory properties. In this study we investigated the effect of visfatin on IFN-γ-induced apoptosis in rat pancreatic β-cells. MethodsThe RINm5F (rat insulinoma cell line) cells exposed to IFN-γ were treated with or without visfatin. The viability and apoptosis of the cells were assessed by using MTT and flow cytometry. The expressionsof mRNA and protein were detected by using real-time PCR and western blot analysis. ResultsThe exposure of RINm5F cells to IFN-γ for 48 h led to increased apoptosis percentage of the cells. Visfatin pretreatment significantly increased the cellviability and reduced the cell apoptosis induced by IFN-γ. IFN-γ-induced increase in expression of p53 mRNA and cytochrome c protein, decrease in mRNA and protein levels of anti-apoptotic protein Bcl-2 were attenuated by visfatin pretreatment. Visfatin alsoincreasedAMPK and ERK1/2phosphorylation and the anti-apoptotic action of visfatin was attenuated by the AMPK and ERK1/2 inhibitor. ConclusionThese results suggested that visfatin protected pancreatic islet cells against IFN-γ-induced apoptosis via mitochondria-dependent apoptotic pathway. The anti-apoptotic action of visfatin is mediated by activation of AMPK and ERK1/2 signaling molecules.     

Effect of Dexamethasone and Aquaporin-1 Antisense Oligonucleotides on the Aquaporin-1 Expression in Cultured Human Trabecular Meshwork Cells

The changes in the expression of aquaporin-1 （AQP1） mRNA and protein in cultured human trabecular meshwork （HTM） cells treated with dexamethasone and transfected with antisense oligonucleotides （AS-ODN） were studied, and the implication of AQP1 regulation in corticosteroid-glaucoma and the possibility of AS-ODN inhibiting the AQP1 expression were evaluated. The cultured HTM cells in vitro were treated with different concentrations of dexamethasone and transfected with oligonucleotides for 5 days respectively. Then, total RNA and protein of HTM cells were extracted. The changes of AQP1 mRNA and protein were demonstrated qualitatively and quantitatively by RT-PCR and Western blot. Band intensities were detected by imaging analysis. There was a parallel relationship between the results of RT-PCR and those of Western blot. The expression levels of AQP1 mRNA and protein in dexamethasone-treated groups were increased initially and decreased later as dexamethasone concentration was stepped up. In the 0.04 μg/mL and 0.4 μg/mL groups, the levels of AQP1 were higher than in control group （0 μg/mL）. In the 4 μg/ mL and 40 μg/mL groups, the AQP1 expression levels were lower than in control group. AS-ODN could down-regulate the expression of AQP1 mRNA and protein in a dose-dependent manner. At 5 μg/mL, down-regulation efficiency reached the maximum. There was no statistically significant difference in the expression of AQP1 mRNA and protein between all sense oligonucleotides groups and control group. It was suggested that dexamethasone may induce the changes of the AQP1 expression in HTM cells to be involved in the occurrence of corticosteroid-glaucoma. AS-ODN can down-regulate the AQP1 expression in HTM cells to some extent.     

PPM1D silencing by lentiviral-mediated RNA interference inhibits proliferation and invasion of human glioma cells

To construct a lentiviral shRNA vector targeting human protein phosphatase 1D magnesium-dependent(PPM1D) gene and detect its effectiveness of gene silencing in human gliomas,specific siRNA targets with short hairpin frame were designed and synthesized.DNA oligo was cloned into the pFU-GW-iRNA lentiviral expression vector,and then PCR and sequencing analyses were conducted to verify the constructs.After the verified plasmids were transfected into 293T cells,the lentivirus was produced and the titer of virus was determined.Real-time quantitative PCR and Western blot were performed to detect the PPM1D expression level in the infected glioma cells.PCR and Western blot analyses revealed the optimal interfering target,and the virus with a titer of 6×108 TU/mL was successfully packaged.The PPM1D expression in human glioma cells was knocked down at both mRNA and protein levels by virus infection.The expression of PPM1D mRNA and protein was decreased by 76.3% and 87.0% respectively as compared with control group.The multiple functions of human glioma cells after PPM1D RNA interference were detected by flow cytometry and cell counting kit-8(CCK-8).Efficient down-regulation of PPM1D resulted in significantly increased cell apoptosis and reduced cell proliferation and invasion potential in U87-MG cells.We have successfully constructed the lentiviral shRNA expression vector capable of stable PPM1D gene silencing at both mRNA and protein levels in glioma cells.And our data gave evidence that the reduced cell growth observed after PPM1D silencing in glioma cells was at least partly due to increased apoptotic cell death.     

Association between Cardiac Changes and Stress,and the Effect of Peroxisome Proliferator-activated Receptor-γ on Stress-induced Myocardial Injury in Mice

This study was aimed to investigate the effect of stress induced by high-intensity exercises on the cardiovascular system. In the epidemiological investigation, 200 subjects(test group) engaged in special high-intensity exercises, and 97 who lived and worked in the same environment and conditions as those in the test group, but did not participate in the exercises served as controls. In the second part of the study, 50 mice were randomly divided into control group, exhaustive swimming group, white noise group, exhaustive swimming plus white noise group, and pioglitazone intervention group. The results showed that the plasma concentrations of the myocardial injury markers heart fatty acid-binding protein(H-FABP), C-reactive protein(CRP), β-endorphin(β-EP) and levels of psychological stress were significantly increased in test group as compared with control group; special high-intensity exercises resulted in a significant elevation of the incidence of cardiac arrhythmias. Animal experiments showed that the plasma levels of corticosterone(CORT) and troponin I(Tn I) were raised while the level of SOD was reduced in exhaustive swimming group, white noise group, and exhaustive swimming plus white noise group. The expression levels of PPARγ m RNA and protein were decreased in myocardial tissues in these groups as well. HE staining showed no remarkable change in myocardial tissues in all the groups. Treatment with pioglitazone significantly decreased the plasma levels of Tn I and CORT, while increased the level of SOD and the expression levels of PPARγ m RNA and protein. It was concluded that the high-intensity exercises may induce a heavy physical and psychological stress and predispose the subjects to accumulated fatigue and sleep deprivation; high-intensity exercises also increases the incidence of arrhythmias and myocardial injury. PPARγ may be involved in the physical and psychological changes induced by high-intensity exercises.