RESUMEN
ObjectiveTo investigate the effect of Yishen Tongluo prescription （YSTLP） on apoptosis of renal tubular epithelial cells and explore the mechanism based on endoplasmic reticulum stress pathway of protein kinase R-like endoplasmic reticulum kinase （PERK）/activating transcription factor 4 （ATF4）/transcription factor C/EBP homologous protein （CHOP）. MethodThe db/db mice were randomly divided into model group， valsartan group （10 mg·kg-1）， and low， middle， high-dose YSTLP groups （1， 2.5， 5 g·kg-1）. Samples were collected after eight weeks of drug intervention. In addition， db/m mice in the same litter served as the control group. Human renal tubular epithelial cells （HK-2） were cultured in vitro and divided into the control group， advanced glycated end-product （AGE） group， and AGE + low， middle， and high-dose YSTLP groups （100， 200， 400 mg·L-1）. TdT-mediated dUTP nick end labeling （TUNEL） staining was used to detect the apoptosis rate of HK-2 cells. Methylthiazolyldiphenyl-tetrazolium bromide （MTT） assay was conducted to detect the viability of HK-2 cells. Calcium fluorescence probe staining and luciferase reporter gene method were adopted to detect the luciferase activity of folded protein response element （UPRE） and endoplasmic reticulum stress. Immunohistochemical （IHC） analysis was carried out to measure the protein expressions of phosphorylated PKR （p-PERK）， CHOP， and ATF4. Real-time polymerase chain reaction （Real-time PCR） was used to measure the mRNA expression levels of CHOP and X-box binding protein 1 （XBP1） in mouse kidney and HK-2 cells. Western blot was used to detect the protein expression level of p-PERK， PERK， CHOP， ATF4， B-cell lymphoma-2 （Bcl-2）， Bcl-2 associated X protein （Bax）， and cleaved Caspase-3 in mouse kidney and HK-2 cells. ResultIn the cellular assay， HK-2 cell viability was significantly reduced， and the apoptosis rate was elevated in the AGE group compared with the control group （P<0.01）. The mRNA and protein expression levels of apoptosis-related factor Bcl-2 were significantly reduced （P<0.01）， and those of Bax were significantly increased （P<0.01）. The protein expression level of cleaved Caspase-3 was significantly increased （P<0.01）. Compared with the AGE group， YSTLP administration treatment resulted in elevated cell viability and reduced apoptosis rate （P<0.01）. The mRNA and protein expression levels of Bcl-2 were significantly elevated in a time- and dose-dependent manner （P<0.01）， and those of Bax were significantly reduced in a time- and dose-dependent manner. The protein expression level of cleaved Caspase-3 was significantly reduced in a time- and dose-dependent manner （P<0.01）. The intracellular Ca2+ imbalance and UPRE luciferase fluorescence intensity were increased in the AGE group compared with the control group （P<0.01）. The mRNA levels of endoplasmic reticulum stress-related factors CHOP and XBP1 were significantly increased （P<0.01）， and the protein expression levels of p-PERK， CHOP， and ATF4 were significantly increased （P<0.05）. Compared with the AGE group， YSTLP effectively improved intracellular Ca2+ imbalance in HK-2 cells and decreased UPRE luciferase fluorescence intensity in a dose-dependent manner （P<0.01）. It reduced the mRNA levels of endoplasmic reticulum stress-related factors CHOP and XBP1 （P<0.01） and the protein expression levels of intracellular p-PERK， CHOP， and ATF4 in a dose- and time-dependent manner （P<0.01）. In animal experiments， the protein expression level of Bcl-2 was significantly reduced（P<0.01）， and that of cleaved Caspase-3 and Bax was significantly increased in the model group compared with the control group （P<0.05）. The protein expression level of Bcl-2 was dose-dependently elevated， and that of cleaved Caspase-3 and Bax was dose-dependently decreased in the YSTLP groups compared with the model group （P<0.01）. Compared with the control group， the mRNA expression levels of CHOP and XBP1 were significantly elevated in the model group （P<0.05， P<0.01）， and the protein expression levels of p-PERK， CHOP， and ATF4 were significantly increased （P<0.05）. Compared with the model group， YSTLP significantly decreased the mRNA expression levels of CHOP and XBP1 （P<0.01） and the protein expression levels of p-PERK， CHOP， and ATF4 （P<0.01）. ConclusionYSTLP can effectively inhibit endoplasmic reticulum stress and improve apoptosis of renal tubular epithelial cells， and its mechanism may be related to the regulation of the PERK/AFT4/CHOP pathway.
RESUMEN
Objective@#Oxygen-glucose deprivation (OGD) is used to mimic ischemia in vitro to observe whether endoplasmic reticulum (ER) stress is involved in human dental pulp cells (hDPCs) after OGD and to better understand the regulatory mechanism of hDPCs in ischemia.@*Methods@# hDPCs were cultured in glucose-free DMEM and hypoxia (volume fraction 2% O2) to establish an hDPCs OGD model in vitro, which mimics hDPCs ischemia in vitro. hDPCs were divided into a control group (normal culture) and an experimental group (OGD 0 h, 2 h, 4 h and 8 h groups). After pretreatment with OGD for 0, 2, 4 and 8 h, hDPC viability was measured by methylthiazol tetrazolium (MTT) assay. qRT-PCR was used to detect the mRNA expression of ER stress markers [splicing x-box binding protein1 (sXBP1), activating transcription Factor 4 (ATF4) and C/EBP homologous protein (chop)]. Western blot was used to detect the protein expression of ER stress markers [phosphorylated RNA-activated protein kinase-like ER-resident kinase (p-perk) and phosphorylated eukaryotic initiation factor-2α (p-eIF2α)]. @*Results@#Compared with OGD 0 h group, cell viability of hDPCs decreased when exposed to OGD treatment for 2 h, 4 h and 8 h. Compared with the control group, mRNA expressions of ER stress makers (sXBP1, ATF4 and chop) and the protein expressions of ER stress protein markers (p-perk andp-eIF2α) increased in OGD treatment cells after 4 h were higher in OGD cells. The differences were statistically significant (P<0.05).@*Conclusion@#The results indicate that ER stress response is involved in hDPCs in OGD treatment.
RESUMEN
Aim To investigate whether endoplasmic reticulum stress is involved in the neurotoxicity of sodi¬um arsenite and clarify whether over-expression of 3-mercaptopyruvate sulfurtransferase (MPST) regulates endoplasmic reticulum stress induced by arsenic. Methods The SH-SY5Y cell line stably expressing the exogenous MPST gene was obtained by constructing the lentiviral vector of MPST gene. The SH-SY5Y cells were randomly divided into six groups, the SR-MPST over-expression group stably expressing the exogenous MPST gene, SH-PEB control group transfected with empty vector, the arsenite treatment group ( NaAs02 group ), TUDC A treatment group ( blocker of endoplasmic reticulum stress ) and TUDC A + NaAs02 group. Western blot was used to examine the protein expression of GRP78 and CHOP after different treatment. Results Although MPST overexpression had no significant effects on the expression of GRP78 and CHOP proteins, NaAs02 could significantly increased the protein levels of GRP78 and CHOP ( P < 0. 01 ) and the up-regulation of GRP78 and CHOP proteins caused by NaAs02 could be blocked by the treatment of TUDC A. In addition, the inhibition by MPST overexpression on the arsenic-induced increase of GRP78 and CHOP proteins (P <0. 01 ) could also be reversed by the TUDC A treatment significantly. Conclusions The GRP78/ CHOP endoplasmic reticulum stress pathway is involved in the neurotoxic damage induced by arsenic; MPST overexpression may decrease arsenic-induced endoplasmic reticulum stress.
RESUMEN
Objective To investigate the role of miR-155 in the development and lung metastasis of osteosarcoma, and to explore its target proteins and related mechanisms. Methods We detected differential miR-155 expression in osteosarcoma and its lung metastasis process through relevant database analysis combined with qPCR detection of clinical tissue and cell samples. iTRAQ quantitative proteomics was used to screen the target protein of miR-155 in osteosarcoma and its lung metastasis. The selected miR-155 target protein was verified by Western blot in clinical tissue and cell samples. Results miR-155 expression was significantly higher in osteosarcoma tissue and lung metastatic tumor tissue than that in the control group. Compared with human normal osteoblasts, miR-155 expression in human osteosarcoma cell line was also significantly increased. A total of 3714 proteins were obtained by iTRAQ assay, and 253 differentially-expressed proteins were screened out, 144 of which were up-regulated and 109 were down-regulated. The prediction analysis and experiment verified that C/EBP β was a potential target protein of miR-155. Conclusion miR-155 expression is significantly increased in osteosarcoma and its lung metastasis process, and C/EBP β is a potential target of miR-155.
RESUMEN
Severe blockage in myeloid differentiation is the hallmark of acute myeloid leukemia (AML). Trdmt1 plays an important role in hematopoiesis. However, little is known about the function of Trdmt1 in AML cell differentiation. In the present study, Trdmt1 was up-regulated and miR-181a was down-regulated significantly during human leukemia HL-60 cell differentiation after TAT-CT3 fusion protein treatment. Accordingly, miR-181a overexpression in HL-60 cells inhibited granulocytic maturation. In addition, our "rescue" assay demonstrated that Trdmt1 3′-untranslated region promoted myeloid differentiation of HL-60 cells by sequestering miR-181a and up-regulating C/EBPα (a critical factor for normal myelopoiesis) via its competing endogenous RNA (ceRNA) activity on miR-181a. These findings revealed an unrecognized role of Trdmt1 as a potential ceRNA for therapeutic targets in AML.
Asunto(s)
Humanos , Leucemia Mieloide Aguda/genética , MicroARNs/genética , ADN (Citosina-5-)-Metiltransferasas/genética , Diferenciación Celular , Células HL-60RESUMEN
Polyphyllin I (PPI) purified from Polyphyllarhizomes displays puissant cytotoxicity in many kinds of cancers. Several researches investigated its anti-cancer activity. But novel mechanisms are still worth investigation. This study aimed to explore PPI-induced endoplasmic reticulum (ER) stress as well as the underlying mechanism in non-small cell lung cancer (NSCLC). Cell viability or colony-forming was detected by MTT or crystal violet respectively. Cell cycle, apoptosis, reactive oxygen species (ROS) and mitochondrial membrane potential were assessed by flow cytometry. Gene and protein levels were evaluated by qRT-PCR and immunoblotting respectively. Protein interaction was determined by immunoprecipitation or immunofluorescence assay. Gene overexpression or silencing was carried out by transient transfection with plasmids or small interfering RNAs. The Cancer Genome Atlas (TCGA) database was used for Gene Set Enrichment Analysis (GSEA), survival analysis, gene expression statistics or pathway enrichment assay. PPI inhibited the propagation of NSCLC cells, increased non-viable apoptotic cells, arrested cell cycle at G2/M phase, induced ROS levels but failed to decrease mitochondrial membrane potential. High levels of GRP78 indicates poor prognosis in NSCLC patients. PPI selectively suppressed unfolded protein response (UPR)-induced GRP78 expression, subsequently protected CHOP from GRP78-mediated ubiquitination and degradation. We demonstrated that the natural product PPI, obtained from traditional herbal medicine, deserves for further study as a valuable candidate for lead compound in the chemotherapy of NSCLC.
RESUMEN
Objective: To investigate the cell death-inducing effect of saikosaponin-d (SSD) on human hepatoma Hep3B cells and its potential mechanism. Methods: Hepatoma Hep3B cells were divided into five groups: blank control group, DMSO (vehicle) group, and three SSD treatment groups treated with various doses of SSD (5, 10, and 15 μmol/L). MTT assay was used to evaluate cell viability. Flow cytometer was employed to quantitatively detect the percentage of dead cells after Annexin V-FITC/PI double staining. Apoptosis was detected morphologically after Hoechst 33258 staining. The activity of caspase-3 apoptotic protease was determined by spectrophotometry. Cell morphologic changes were observed with an inverted microscope. Western blotting and Real-time PCR were employed to evaluate the expression levels of C/EBP homology (CHOP) protein and mRNA, respectively. Results: MTT assay showed that SSD inhibited the viability of human hepatoma Hep3B cells in concentration- and time-dependent manners. Sinomenine hydrochloride induced the death of Hep3B cells in a concentration-dependent manner indicated by flow cytometry. After staining with Hoechst 33258, the nuclei of SSD-treated cells showed nucleosomal agglutination, nucleosomal shrinkage and fragmentation under the fluorescence microscope, which are the characteristics of apoptotic cells. SSD significantly activated the key apoptotic executor caspase-3. The occurrence of paraptosis, characterized by extensive cytoplasmic vacuoles, was observed in SSD-treated cells under an inverted microscope. The pretreatment of a pancaspase inhibitor Z-VAD-FMK completely inhibited caspase-3 activity triggered by SSD, but only partially suppressed cell death and could not reduce the cytoplasmic vacuolation in SSD-treated cells. The protein and mRNA expressions of CHOP, a stress-inducible molecule, were upregulated by SSD, which could not be inhibited by Z-VAD-FMK. Conclusion: SSD can simultaneously induce caspase-dependent apoptosis and caspase-independent paraptosis in human hepatoma Hep3B cells. The upregulated expression of CHOP may be the mechanism involved in SSD-induced paraptosis.
RESUMEN
AIM: To investigate the inhibitory effects of endoplasmic reticulum stress(ERS) and TRAIL on hepatic stellate cells in vitro and how their interaction affect the apoptosis of hepatic stellate cells. METHODS: Take thapsigargin (TG) as the endoplasmic reticulum stress-inducing agents, ursodeoxycholic acid (UDCA) for the endoplasmic reticulum stress inhibitors, SP600125 as a c-Jun N-terminal kinase(JNK) inhibitor, HSC-T6 cells were divided into normal control group, DMSO group, TRAIL group, TG group, UDCA group, siCHOP group and SP600125 group. The apoptosis rate of HSC-T6 cell was detected by flow cytometry. Small interference RNA was applied to silence C/EBP homologous protein(CHOP) gene. The protein expression levels of Caspase-8 were detected by immunohistochemistry method. The ERS marker protein CHOP and TRAIL receptor DR5 expression levels were determined by RT-PCR and Western blot. RESULTS:TG (1 μmol/L, 2 μmol/L, 4 μmol/L, 8 μmol/L, 16 μmol/L) increased cell apoptosis rate of HSC-T6. RT-PCR and Western blot showed that the endoplasmic reticulum stress protein marker CHOP could induce the upregulation of TRAIL receptor DR5 and Caspase-8. Moreover, siCHOP and the JNK inhibitor SP600125 could reduce the expression of DR5 and Caspase-8 in HSC cells. CONCLUSION: These results indicated that CHOP and JNK may be a potential factor regulating DR5 expression, and play an important role in the process of apoptosis of hepatic stellate cells.
RESUMEN
The objective was to investigate the effect of kinsenoside (Kin) treatments on macrophage polarity and evaluate the resulting protection of chondrocytes to attenuate osteoarthritis (OA) progression. RAW264.7 macrophages were polarized to M1/M2 subtypes then administered with different concentrations of Kin. The polarization transitions were evaluated with quantitative real-time polymerase chain reaction (qRT-PCR), confocal observation and flow cytometry analysis. The mechanism of Kin repolarizing M1 macrophages was evaluated by Western blot. Further, macrophage conditioned medium (CM) and IL-1 were administered to chondrocytes. Micro-CT scanning and histological observations were conducted on anterior cruciate ligament transection (ACLT) mice with or without Kin treatment. We found that Kin repolarized M1 macrophages to the M2 phenotype. Mechanistically, Kin inhibited the phosphorylation of IB, which further reduced the downstream phosphorylation of P65 in nuclear factor-B (NF-B) signaling. Moreover, Kin inhibited mitogen-activated protein kinases (MAPK) signaling molecules p-JNK, p-ERK and p-P38. Additionally, Kin attenuated macrophage CM and IL-1-induced chondrocyte damage. , Kin reduced the infiltration of M1 macrophages, promoted M2 macrophages in the synovium, inhibited subchondral bone destruction and reduced articular cartilage damage induced by ACLT. All the results indicated that Kin is an effective therapeutic candidate for OA treatment.
RESUMEN
AIM:To investigate the effects of Jiawei-Naotai formula (JWNTF) on ATF4/CHOP/Puma pathway in hippocampal neurons of ovariectomized female rats with cerebral ischemia.METHODS:The female rats were randomly divided into sham group, model group, JWNTF group and positive control group.The rats, expect in the sham group, were ovariectomized.The rats in each group were intragastric administration 11 days after ovariectomy.The rats in sham group and model group were given a gavage of 0.9％Na Cl, while the rats in other groups were administrated by corresponding therapy intragastrically for 3 d.The regional cerebral ischemia model was established by middle cerebral artery occlusion (MCAO) suture method 14 days after ovariectomy.The behaviors of the rats were evaluated 24 h after cerebral ischemia.The mRNA levels of Bax, Bcl-2 and caspase-3 were detected by RT-qPCR, and the protein expression of Bax, Bcl-2, caspase-3, ATF4, CHOP and Puma was determined by Western blot.RESULTS:Compared with sham group, the neurobehavioral scores significantly increased in other groups (P<0.05).Compared with model group, the neurobehavioral scores were significantly decreased in positive control group and JWNTF group (P<0.05).The protein expression of Bax, caspase-3, ATF4, CHOP and Puma, and the mRNA expression of Bax and caspase-3 in the hippocampus were much higher, and Bcl-2 was lower in model group than those in sham group (P<0.05).JWNTF significantly reduced the protein expression of Bax, caspase-3, ATF4 and CHOP, and the mRNA expression of Puma, Bax and caspase-3, and markedly increased the expression of Bcl-2 at mRNA and protein levels compared with model group.CONCLUSION:The JWNTF protects against brain damage induced by cerebral ischemia, which may be related to inhibitiing the expression of ATF4/CHOP/Puma pathway-related molecules at mRNA and protein levels.
RESUMEN
Objective: To investigate the effects and mechanisms of iridoid glycosides of Scrophulariae Radix (IGRS) via endoplasmic reticulum stress-mediated apoptosis pathway on the primary cortical neurons induced by oxygen glucose deprivation/reperfusion (OGD/R). Methods: Newborn SD rats were performed primary cortical neurons culture. And the primary cortical neurons were pretreated with IGRS (50, 100, and 200 μg/mL) for 24 h, and the in vitro model of oxygen-glucose deprivation/reoxygenation (OGD/R) was applied. The neurons purity and morphology were observed under inverted microscope, the cell viability was detected by MTT assay; the intracellular lactate dehydrogenase (LDH) level and superoxide dismutase (SOD) activity were detected by commercial kit. The apoptotic rate was detected by flow cytometry. The expression of C/EBP homologous protein (CHOP), glucose-regulated protein-78 (GRP78) and Caspase-12 protein were detected by western blotting. Results: The cultured primary cortical neurons were plump with high purity in good condition. Compared with the control group, the primary cortical neurons were retracted and rounded after OGD/R treatment, and the surface of the neurons became rough; The cell viability and SOD activity were significantly decreased; The LDH level and apoptotic rate were evidently increased; The expression of CHOP, Caspase-12, and GRP78 were significantly increased. Compared with the model group, IGRS could relieve neurons damage, increase cell viability and SOD activity, decrease LDH level and apoptotic rate, and down-regulate the expression of CHOP, Caspase-12, and GRP78. Conclusion: IGRS can antagonize the neuronal damage induced by OGD/R in primary cortical neurons, and its mechanism is related to the inhibition of endoplasmic reticulum stress-mediated apoptosis.
RESUMEN
Objective To detect the activation levels of endoplasmic reticulum stress ATF6-CHOP pathway,and to investigate the molecular mechanism of tannic acid (TA) combined with cisplatin (CDDP) against hepatocellular carcinoma.Methods HepG2 cells were cultured with 180 μM TA or/and 0.9 μg/ml CDDP for 24 h or 48 h.The levels of ATF6 (ATF6α),ATF6B (ATF6β) and CHOP were analyzed by real-time fluorescence quantitative PCR (q-RT-PCR) and western blot.Results We found that after 24 h or 48 h,compared with the control group,ATF6 mRNA and protein levels,ATF6B protein level,CHOP mRNA and protein levels were significantly increased in the TA group,CDDP group or combination group (P ＜ 0.01 or P ＜ 0.05).Conclusion TA can combine with CDDP to increase the levels of endoplasmic reticulum stress ATF6-CHOP pathway,and the ATF6-CHOP pathway may be one of the molecular mechanisms synergistic anti-hepatocellular carcinoma effect of TA and CDDP on HepG2 cells.
RESUMEN
AIM:To investigate the inhibitory effect of ethanol extract of propolis (EEP) on oxidized low-density lipoprotein (ox-LDL)-induced vascular endothelial cell apoptosis and the underlying molecular mechanisms.METHODS:Human umbilical vein endothelial cells (HUVECs) were pretreated with EEP (7.5,15 and 30 mg/L) or 4-phenylbutyric acid (PBA,4 mmol/L) for 1 h and then treated with ox-LDL (100 mg/L) or tunicamycin (TM,4 mg/L) for 24 h.The cell viability and apoptosis were determined by MTT assay and Annexin V-FITC/PI double staining,respectively.The activities of lactic dehydrogenase (LDH) in the medium and caspase-3 in the HUVECs were measured.The protein and mRNA levels of C/EBP homologous protein (CHOP),a proapoptotic molecule under endoplasmic reticulum stress (ERS),and its downstream Bcl-2 were examined by Western blot and real-time PCR,respectively.RESULTS:Like PBA (an ERS inhibitor),EEP protected HUVECs from ox-LDL-induced injury in a dose-dependent manner,as assessed by the increased cell viability and the decreased LDH release,apoptotic rate and caspase-3 activation.The decrease in cell viability and the increases in LDH release,apoptotic rate and caspase-3 activation induced by TM,an ERS inducer,were also attenuated by EEP.Moreover,EEP suppressed ox-LDL-induced CHOP upregulation and Bcl-2 downregulation,and this effect was similar to that of PBA.Similarly,EEP significantly suppressed TM-induced CHOP upregulation both at the protein and mRNA levels.CONCLUSION:EEP may protect HUVECs from ox-LDL-induced apoptosis,and the mechanism is at least partially involved in suppressing CHOP-mediated ERS-associated apoptotic pathway.
RESUMEN
AIM:To investigate the inhibitory effect of ethanol extract of propolis (EEP) on oxidized low-density lipoprotein (ox-LDL)-induced vascular endothelial cell apoptosis and the underlying molecular mechanisms.METHODS:Human umbilical vein endothelial cells (HUVECs) were pretreated with EEP (7.5,15 and 30 mg/L) or 4-phenylbutyric acid (PBA,4 mmol/L) for 1 h and then treated with ox-LDL (100 mg/L) or tunicamycin (TM,4 mg/L) for 24 h.The cell viability and apoptosis were determined by MTT assay and Annexin V-FITC/PI double staining,respectively.The activities of lactic dehydrogenase (LDH) in the medium and caspase-3 in the HUVECs were measured.The protein and mRNA levels of C/EBP homologous protein (CHOP),a proapoptotic molecule under endoplasmic reticulum stress (ERS),and its downstream Bcl-2 were examined by Western blot and real-time PCR,respectively.RESULTS:Like PBA (an ERS inhibitor),EEP protected HUVECs from ox-LDL-induced injury in a dose-dependent manner,as assessed by the increased cell viability and the decreased LDH release,apoptotic rate and caspase-3 activation.The decrease in cell viability and the increases in LDH release,apoptotic rate and caspase-3 activation induced by TM,an ERS inducer,were also attenuated by EEP.Moreover,EEP suppressed ox-LDL-induced CHOP upregulation and Bcl-2 downregulation,and this effect was similar to that of PBA.Similarly,EEP significantly suppressed TM-induced CHOP upregulation both at the protein and mRNA levels.CONCLUSION:EEP may protect HUVECs from ox-LDL-induced apoptosis,and the mechanism is at least partially involved in suppressing CHOP-mediated ERS-associated apoptotic pathway.
RESUMEN
AIM:To study the effect of transient receptor potential channel 1 ( TRPC1) on the survival of hip-pocampal neurons in mice.METHODS:TRPC1 knockout mice and the control mice (6 months old) were used in this study.Immunofluorescence staining of neuron-specific marker NeuN, Nissl staining and TUNEL staining were performed to measure the changes of the neurons in hippocampal CA1, CA3 and dentate gyrus (DG).Western blot analysis was used to detect the levels of pro-apoptotic protein C/EBP homologous protein ( CHOP) and cleaved caspase-3.RESULTS:Immuno-fluorescence staining and Nissl staining showed that the number of neuronal cells was significantly decreased in hippocampal CA1, CA3 and DG of TRPC1 knockout mice compared with the control mice.TUNEL staining showed that the apoptosis neuronal cell number of the above areas in TRPC1 knockout mice was significantly increased compared with the control mice.The results of Western blot revealed that the levels of CHOP and cleaved caspase-3 were significantly increased in the hippocampus of TRPC1 knockout mice relative to the control mice.CONCLUSION:The depletion of TRPC1 induces neu-ronal loss through a mechanism of TRPC1-mediated apoptosis.
RESUMEN
Mounting evidence demonstrates that CYP2B6 plays a much larger role in human drug metabolism than was previously believed. The discovery of multiple important substrates of CYP2B6 as well as polymorphic differences has sparked increasing interest in the genetic and xenobiotic factors contributing to the expression and function of the enzyme. The expression of CYP2B6 is regulated primarily by the xenobiotic receptors constitutive androstane receptor (CAR) and pregnane X receptor (PXR) in the liver. In addition to CYP2B6, these receptors also mediate the inductive expression of CYP3A4, and a number of important phase II enzymes and drug transporters. CYP2B6 has been demonstrated to play a role in the metabolism of 2%-10% of clinically used drugs including widely used antineoplastic agents cyclophosphamide and ifosfamide, anesthetics propofol and ketamine, synthetic opioids pethidine and methadone, and the antiretrovirals nevirapine and efavirenz, among others. Significant inter-individual variability in the expression and function of the human CYP2B6 gene exists and can result in altered clinical outcomes in patients receiving treatment with CYP2B6-substrate drugs. These variances arise from a number of sources including genetic polymorphism, and xenobiotic intervention. In this review, we will provide an overview of the key players in CYP2B6 expression and function and highlight recent advances made in assessing clinical ramifications of important CYP2B6-mediated drug-drug interactions.
RESUMEN
OBJECTIVE To examine the reversal effect of desipramine (DMI) on resistance to temozolomide(TMZ) in U251/TR cells and explore its mechanism. METHODS U251/TR cells were exposed to DMI (20-80μmol · L-1) or TMZ (0.5-10 mmol · L-1) for 24 h, cell viability was determined by cell counting kit-8 assay with IC50 calculated. The cytotoxicity of U251/TR cells treated with TMZ (1 or 2 mmol·L-1) in combination with DMI (20, 30 or 40 μmol · L-1) for 24 h was detected using CCK-8 assay. Synergism between DMI and TMZ was analyzed by the JIN Zheng-jun method. Apoptosis of U251/TR cells induced by TMZ 1 mmol · L-1, DMI 30 μmol · L-1,or their combination was examined by Hoechst33258 stains and caspase 3 activity was detected by luminescence analysis. Expression of C/EBP homologous protein (CHOP) was measured using quantitative real-time PCR and Western blotting. The survival rate of U251/TR cells treated with TMZ 1 mmol·L-1 and/or DMI 30μmol·L-1 was also assessed after silencing CHOP expression by small interference RNA (siRNA). RESULTS DMI or TMZ alone inhibited the growth of U251/TR cells significantly in a concentration-dependent manner (r 2=0.983,0.982,P1.15), ie, compared with TMZ alone, TMZ (1 mmol·L-1) com?bined with DMI (30 μmol · L-1) produced significant nuclear fragmentation and condensation (P< 0.05). In addition, DMI and TMZ in combination activated caspase 3 activity in U251/TR cells (P<0.05). Knock?down of CHOP by specific siRNA attenuated the synergistic effect of DMI in the presence of TMZ, the survival rate of the combined drug group raised from 51.8%to 62.2%(P<0.05). CONCLUSION The results suggest that DMI reverse resistance of U251/TR cells to TMZ through activation of the CHOP-depend?ently apoptosis pathway.
RESUMEN
Objective To explore the expression changes of C/EBP homologous binding protein (CHOP)in intermittent hypoxic rats with cognitive function decline and clinical significance.Methods We randomly divided 75 adult male Wistar rats into normal group (NC group),5% intermittent hypoxia group (5% CIH group)and 10%intermittent hypoxia group (10% CIH group),with 25 rats in each.Then the three groups were further divided into 3 d,7 d,14 d,21 d and 28 d subgroups,and each time a subgroup had 5 rats.The control group was exposed to the air while 10% CIH group and 5% CIH group were exposed to CIH for eight hours from 8:00 to 1 6:00 each day. After exposure for 3 d,7 d,14 d,21 d and 28 d,the cognitive function of rats was assessed with Morris water maze, the expression of CHOP in the hippocampus was assayed qualitatively by immunohistochemical technique,and the apoptosis of neurons was detected by TUNEL method.Results ① With prolonged hypoxia,the time of escape latency obviously prolonged,the time spent crossing the target quadrant shortened (P < 0.05 ),and the apoptosis index of hippocampal neurons in the CIH groups was increased gradually compared with those in control group (P <0.05).The above-mentioned indexes changed more significantly in 5% CIH group than in 10% CIH group (P <0.05).②.The expression of CHOP protein at each time point was increased (P <0.05 ).In 10% CIH group it reached the peak at 28 d while in 5% CIH group it decreased after it peaked at 21 d.③ The expression of CHOP in the two CIH groups was positively correlated with apoptosis index and animal escape latency time,but negatively correlated with the target quadrant time.Conclusion Intermittent hypoxia,which is likely to induce the high expression of CHOP and activation of neural CHOP mediated apoptosis,causes cognitive impairment of various degrees.
RESUMEN
Objective To investigate the effect and mechanism of phosphorylated protein kinase R-like ER kinase(p-PERK) and C/EBP homologous protein(CHOP) after hypoxic-ischemic brain damage ( HIBD) . Methods Neonatal 7-day-old Sprague Dawley rats were divided into sham-operation control group and HIBD group( n=30 per group) . Each group was divided into 0 h,6 h and 24 h subgroup after operation ( n=10 per group) . The ratio of apoptosis of brain cell was measured by flow cytometer and the expression of p-PERK and CHOP were detected by Western blot. Results (1)Apoptosis cell appeared at 6 h in HIBD group,the ratio of cell apoptosis was(2. 17 ± 0. 19)%. The apoptosis cell obvious increased at 24 h,the ratio of cell apoptosis was(13. 42 ± 0. 83)%. There was a significant increase in the ratio of apoptosis after HIBD 6 h and 24 h, as compared with sham-operation control group [ ( 0. 57 ± 0. 06 )%( P <0. 01 ) ] . ( 2 ) The expression of both p-PERK and CHOP was very low in sham-operation control group. In the HIBD group,the expression of both p-PERK and CHOP began to increase at 6 h and increased furthermore at HIBD 24 h. The differences in the expression levels of p-PERK and CHOP in HIBD group among different time points were significant( P<0. 01 ) . ( 3 ) The expression of p-PERK positively correlated with the expression of CHOP (r=0. 997,P< 0. 05). Conclusion With the emerging of apoptosis after HIBD,the expression of both p-PERK and CHOP increases. The imbalance in the expression of PERK induces the apoptosis of brain cells in the HIBD of neonatal rats by regulation of CHOP expression.
RESUMEN
Objective To investigate the effect of CCK-8 on CHOP/caspase-11/caspase-1 expressions induced by LPS in RAW264.7 cells.Methods RAW264.7 cells were incubated with LPS and/or CCK-8 and/or CCK-8 1R blocking agent devazepide for indicated times .CHOP and caspase-11 protein expressions were determined by West-ern blot , caspase-1 activity was analyzed by kit , IL-1βexpression level was analyzed by ELISA .Results Both CHOP and caspase-11 expression were upregulated in LPS-activated RAW264.7 cell, which were inhibited by pre-treatment of CCK-8 .Pre-treatment of devazepide inhibited the effects of CCK-8 significantly .The same effects were found in caspase-1 activity and IL-1βexpression .Conclusions CCK-8 exerts an anti-inflammatory effect by inhib-iting CHOP/caspase-11/caspase-1 expressions induced by LPS in RAW264.7 cell.CCK 1R may contribute to the anti-inflammatory effect of CCK-8.