Expression Of Glucose-regulated Protein 78 mRNA Research Articles

Endoplasmic Reticulum Stress in Myometrial Smooth Muscle Cells and Spontaneous Contraction Changes in the Uterus of Dehydroepiandrosterone-induced Polycystic Ovary Syndrome Rats.

Myometrial changes in polycystic ovary syndrome (PCOS) are poorly investigated. Thus, we aimed to investigate endoplasmic reticulum (ER) stress in myometrial smooth muscle cells and changes in spontaneous uterine contraction in PCOS. Twenty-one female Sprague-Dawley rats (21 days old) were divided into control (n = 7), vehicle (n = 7) and PCOS (n = 7) groups. While the control group was not injected subcutaneously, the vehicle group was injected subcutaneously with sesame oil (0.2 ml/day) for 20 consecutive days. The PCOS group was injected subcutaneously with dehydroepiandrosterone (6 mg/100 g/day dissolved in 0.2 ml sesame oil) for 20 consecutive days. Blood samples were collected for the measurement of follicle stimulating-hormone (FSH), luteinizing hormone (LH), testosterone (T), estradiol (E2) and glucose-regulated protein 78 (GRP78). The mRNA expression of GRP78 in the uterine tissue samples was analysed by quantitative real-time polymerase chain reaction. GRP78 protein expression was assessed by immunohistochemistry. Myometrial smooth muscle cells were examined by transmission electron microscopy. Uterine contractions were evaluated with isolated organ bath experiments. In the PCOS group, T and LH levels increased significantly, although FSH and E2 levels decreased, but this decrease was not statistically significant. Additionally, GRP78 levels increased significantly in the PCOS group. In the PCOS group, the mRNA level, immunostaining intensity of GRP78, and ER damage grade increased, but the uterine tissue calcium levels, and the frequency and amplitude of spontaneous uterine contractions decreased. The results indicated that increased ER stress in myometrial smooth muscle cells may play a causative role in the decreased spontaneous uterine contractions in PCOS.

Mechanistic Research into the Effects of the Jianpi Xiaozhi Formula on Liver Injury in Diabetic Rats.

Objective The purpose of this study was to explore the mechanism of Jianpi Xiaozhi Formula (JPXZF) action in attenuating liver injury in a rat model of type 2 diabetes mellitus (T2DM). Methods A rat model of T2DM was established. Forty-eight male Sprague–Dawley (SD) rats were randomly allocated to six groups: healthy untreated rats (normal control (NC)), rats with diabetes mellitus (DM), diabetic rats treated with low-dosage JPXZF (DM + JL), diabetic rats treated with an intermediate JPXZF dosage (DM + JM), diabetic rats treated with high-dosage JPXZF (DM + JH), and diabetic rats treated with 4-phenylbutyric acid (PBA) (DM + PBA). The rats in each group were given the indicated drugs for 8 weeks, and pathological changes in the liver tissues of each rat group were observed by haematoxylin-eosin (HE) staining. Reverse-transcription polymerase chain reaction (RT-PCR) and Western blotting (WB) were performed to determine the expression of glucose-regulated protein 78 (GRP78), activating transcription factor 6 (ATF6), family with sequence similarity 134, member B (FAM134B), P62, Beclin-1, and light chain 3II/I (LC3II/I) genes and proteins in the liver tissues of the rats in each group. Immunofluorescence was used to observe changes in FAM134B expression. Results After successfully establishing the rat model, RT-PCR assays revealed that, compared with those in the NC group rats, the expression levels of GRP78, ATF6, and P62 mRNA in the livers of the DM group rats were significantly increased, and the relative expression levels of FAM134B and Beclin-1 mRNA were significantly decreased. Compared with that in the DM group, the relative expression of GRP78, ATF6, and P62 mRNA in the liver of the rats in each JPXZF intervention group was decreased in a dosage-dependent manner, and the relative expression of FAM134B and Beclin-1 mRNA was increased significantly (p < 0.05). WB indicated that, compared with that in the NC group rats, the LC3II/I protein expression ratio in the liver of the DM group rats was significantly reduced, and the LC3II/I protein expression ratio in the liver of the rats in each JPXZF intervention group was significantly increased. In addition, the expression of the other measured proteins was consistent with that of the corresponding mRNA measured by RT-PCR (p < 0.05). The immunofluorescence assay results showed that FAM134B changes were consistent with the results obtained by RT-PCR and WB (p < 0.05). Conclusion Jianpi Xiaozhi Formula may be effective in treating liver injury in diabetic rats by regulating autophagy induced by endoplasmic reticulum stress (ERS).

Mechanistic Insights into Ameliorating Effect of Geraniol on d-Galactose Induced Memory Impairment in Rats

Geraniol (GE), an important ingredient in several essential oils, displayed pleiotropic biological activities through targeting multiple signaling cascades. In the current study, we aimed to examine the protective effect of GE on d-galactose (d-gal) induced cognitive impairment and explore the underlying mechanisms. Forty male Wistar rats (8 weeks old) were randomly categorized into 4 groups; Group I (saline + vehicle [edible oil]), group II (saline + geraniol) (100 mg/kg/day orally), group III (d-galactose) (100 mg/kg/day subcutaneously injected), and group IV (d-galactose + geraniol). Behavioral impairments were evaluated. Brain levels of malondialdehyde (MDA) and reduced glutathione (GSH) as well as superoxide dismutase (SOD) and acetylcholinesterase (AchE) activities were estimated. The levels of inflammatory markers [tumor necrosis factor-alpha (TNF-α), interleukin (IL)-1β, IL-6, and nuclear factor kappa beta (NF-kβ)], endoplasmic reticulum stress sensors [inositol requiring protein 1(IRE1) and protein kinase RNA–like endoplasmic reticulum kinase (PERK)], brain-derived neurotrophic factor (BDNF), and mitogen-activated protein kinases (MAPK) pathway were measured by ELISA. Also, hippocampal histopathological assessment and immunohistochemical analysis of glial fibrillary acidic protein (GFAP) and caspase-3 were performed. Glucose regulated protein 78 (GRP78) and C/EBP homologous protein (CHOP) mRNA expression and protein levels were assessed. GE effectively ameliorated aging-related memory impairment through increasing GSH, BDNF, Ach levels, and SOD activity. Additionally, GE treatment caused a decrease in the levels of MDA, inflammatory mediators, and ER stress sensors as well as the AchE activity together with concomitant down-regulation of GRP78 and CHOP mRNA expression. Moreover, GE improved neuronal architecture and rat's spatial memory; this is evidenced by the shortened escape latency and increased platform crossing number. Therefore, GE offers a unique pharmacological approach for aging-associated neurodegenerative disorders.Graphical

Enhanced GRP78 protein expression via the IRE1α/ASK1/p38 MAPK pathway during As2O3-induced endoplasmic reticulum stress in BEAS-2B cells

Inorganic arsenic is widely present in the environment. Exposure to moderate to high concentrations of arsenic from drinking water or air can cause various cancers and multisystem dysfunction. Glucose-regulated protein 78 (GRP78) is an endoplasmic reticulum (ER) stress sensor of unfolded protein response (UPR) under stress conditions and it enhances cell survival. The aim of this study is to investigate molecular mechanisms of arsenic-induced GRP78 expression in BEAS-2B cells model. We found that GRP78 protein expression was enhanced, while the level of GRP78 mRNA expression did not change under arsenic trioxide (As2O3)-induced ER stress condition in BEAS-2B cells. Cycloheximide, a protein synthesis inhibitor, completely inhibited As2O3-induced GRP78 protein expression. GRP78 mRNA expression was inhibited by actinomycin-D (Act-D). However, GRP78 protein expression was upregulated in the presence of Act-D under As2O3-induced ER stress condition. These data indicated that the upregulation of GRP78 protein under As2O3-induced UPR condition was possibly due to the increased biosynthesis of GRP78 protein. Moreover, both inositol-requiring enzyme 1α (IRE1α) RNase and kinase inhibitor KIRA6 and IRE1α kinase inhibitor APY29 completely inhibited As2O3-induced GRP78 protein expression and phosphorylation of JNK, ERK and p38 MAPK. Activation of apoptotic signaling kinase 1 (ASK1) is a downstream effector of IRE1α kinase. ASK1 inhibitor selonsertib and p38 MAPK inhibitor SB203580 partially inhibited As2O3-induced GRP78 protein expression, respectively. Our results suggested that As2O3 enhanced GRP78 protein expression in BEAS-2B cells via IRE1α kinase/ASK1/p38 MAPK signaling pathway. To our knowledge, this is the first report on illuminating the related mechanisms of increased GRP78 protein expression in As2O3-induced ER stress condition through a novel IRE1α pathway.

Glucose- regulated protein 78 (GRP78) in renal cell carcinoma: A novel biomarker for predicting tumor behavior

ObjectiveTo study the mRNA and protein expression of GRP78 in tumor and serum of the RCC patients and compare with the controls and to correlate the expression with the grade and stage of RCC. Materials and methodsA prospective cohort study involving 60 patients planned for radical/partial nephrectomy for primary RCC between July 2017 to June 2019. The RCC and adjacent non-tumorous renal tissues (Control) along with serum samples of patients were collected. Control for the serum samples is from the patients undergoing simple nephrectomy for non-functioning kidney due to benign etiology. The GRP78 expression was studied using RT-PCR for mRNA expression, Western blot analysis and immunohistochemistry (IHC) for protein expression and using ELISA in serum for both the subjects and controls. ResultsMean age of patients was 50.3 years. The mRNA and protein expression of GRP78 in tissue samples were significantly higher in RCC patients as compared to controls (p < 0.001). IHC also demonstrated significantly higher expression in tumour samples as compared to controls (p < 0.001). Circulatory levels of GRP78 in serum samples were also significantly increased (p < 0.0001) in RCC patients in comparison to control subjects. The expression of GRP78 in circulation significantly correlated with the pathological tumor stage (p = 0.03), grade of disease (p < 0.001). ConclusionThe GRP78 in RCC is significantly upregulated both at molecular and protein level expression. The overexpression of GRP78 correlates with the stage and grade of disease, thereby, highlighting its prognostic ability.

Effect of penehyclidine hydrochloride on hyperoxia-induced acute lung injury and the relationship with endoplasmic reticulum stress-dependent apoptosis in infantile rats

Objective To evaluate the effect of penehyclidine hydrochloride on hyperoxia-induced acute lung injury and the relationship with endoplasmic reticulum stress-dependent apoptosis in infantile rats. Methods Ninety-six clean-grade male infantile Sprague-Dawley rats, weighing 40-50 g, aged 14 days, were allocated into 4 groups (n=24 each) using a random number table method: control group (C group), penehyclidine hydrochloride group (P group), hyperoxia group (HO group) and hyperoxia plus penehyclidine hydrochloride group (HP group). Infantile rats were intravenously injected with penehyclidine hydrochloride (0.3 mg/kg) at the same time point every day for 3 consecutive days in P and HP groups.Infantile rats were injected with the equal volume of normal saline instead of penehyclidine hydrochloride in C and H groups.Acute lung injury was induced by inhaling oxygen at concentration greater than 90% for 72 h starting from 4th day after administration.Infantile rats were sacrificed at the end of inhaling, and lungs were removed for examination of the pathological changes and for determination of weight to dry weight ratio (W/D ratio), index of quantitative evaluation for alveolar damage (IQA), pneumonocyte apoptosis (using TUNEL), expression of glucose-regulated protein 78 (GRP78) and CCAAT/enhancer-binding protein homologous protein(CHOP) protein and mRNA in lung tissues (by Western blot or using reverse transcription-polymerase chain reaction). The mitochondrial injury score was assessed, and apoptotic index (AI) was determined. Results Compared with C group, the W/D ratio, IQA, AI and mitochondrial injury score were significantly increased, and the expression of GRP78 and CHOP protein and mRNA was up-regulated in HO and HP groups(P 0.05). Compared with HO group, the W/D ratio, IQA, AI and mitochondrial injury score were significantly decreased, the expression of GRP78 and CHOP protein and mRNA was down-regulated (P<0.05), and the pathological changes of lung tissues were significantly attenuated in HP group. Conclusion Penehyclidine hydrochloride can mitigate hyperoxia-induced acute lung injury, and the mechanism may be related to inhibiting endoplasmic reticulum stress-dependent apoptosis in infantile rats. Key words: Cholinergic antagonist; Acute lung injury; Hyperoxia; Endoplasmic reticulum stress; Apoptosis

The effect of L-carnitine on the apoptosis of human lens epithelial cells through endoplasmic reticulum stress

Objective: To investigate the effect of L-carnitine on the apoptosis of human lens epithelial cells through endoplasmic reticulum (ER) stress pathway. Methods: HLE-B3 cell lines were used to set up an oxidative stress model with H(2)O(2) treatment for 12 h, and lead to ER stress. Cells were divided into four groups: H(2)O(2) group, L-carnitine (100 μmol/L) with H(2)O(2) group, phosphate buffered saline (PBS) group and L-carnitine (100 μmol/L) group. Cell counting kit-8 was used to detect the cell viability under the treatment of different concentrations (200, 400, 600 and 800 μmol/L) of H(2)O(2). The apoptosis ratio of HLE-B3 treated by 400 μmol/L H(2)O(2) was tested by flow cytometry. When HLE-B3 was treated by 400 μmol/L H(2)O(2), the expression levels of cysteinyl aspartate specific proteinase 3 (caspase-3) gene and glucose-regulated protein 78 (GRP78) gene were measured by RT-PCR, and the expression levels of caspase-3 protein and GRP78 protein were assayed by Western blotting. Data from groups was analyzed by the one-way analysis of variance, and the LSD-t test was used for the comparison of groups. Results: Cell counting kit-8 assay showed that when H(2)O(2) concentration was 200, 400, 600 and 800 μmol/L, there was significant difference in the H(2)O(2) group(77.6%±0.8%,58.1%±3.1%,39.2%±1.5%,28.1%±2.2%), L-carnitine with H(2)O(2) group(83.3%±4.2%,74.5%±3.1%,46.4%±1.7%,32.4%±1.2%), PBS group(97.6%±2.1%,98.3%±0.2%,96.3%±2.2%,98.5%±1.1%) and L-carnitine group(98.5%±1.3%, 96.1%±2.1%, 98.1%±0.2%, 97.3%±1.4%) (all P<0.05). There was no significant difference between groups (PBS group compared to L-carnitine group, all P>0.05). When the concentration of H(2)O(2) was 400 μmol/L, the survival rate of the L-carnitine with H(2)O(2) group was higher than the H(2)O(2) group. The difference was statistically significant (t=18.14, P=0.020). With increasing of the H(2)O(2) concentration, cell necrosis was increased. The cell survival rate had no significant difference between the L-carnitine with H(2)O(2) group and H(2)O(2) group (both P>0.05). Flow cytometry results of the H(2)O(2) group, L-carnitine with H(2)O(2) group, PBS group and L-carnitine group were 31.4%±4.5%, 16.5%±2.8%, 2.1%±0.2% and 1.9%±1.8%, respectively (F=126.784, P=0.024) . The rate of apoptosis in the L-carnitine with H(2)O(2) group was lower than that in the H(2)O(2) group (t=24.67, P=0.013). There was no significant difference between the PBS group and L-carnitine group (P>0.05). The results of RT-PCR showed that the expression of caspase-3 mRNA in the L-carnitine with H(2)O(2) group was lower than the H(2)O(2) group (0.424±0.041 vs. 0.752±0.203), and the expression of GRP78 mRNA in the L-carnitine with H(2)O(2) group was lower than the H(2)O(2) group (0.521±0.223 vs. 0.821±0.103). The difference was statistically significant (caspase-3: t=27.92, P=0.018;GRP78: t=16.31, P=0.019). Western blotting showed that the protein expression of caspase-3 in the L-carnitine with H(2)O(2) group was lower than the H(2)O(2) group (0.712±0.212 vs. 1.126±0.251), and the GRP78 protein expression in the L-carnitine with H(2)O(2) group was lower than the H(2)O(2) group (0.512±0.012 vs. 0.735±0.051). The difference was statistically significant (caspase-3: t=15.43, P=0.010;GRP78: t=20.62, P=0.018). Conclusion: L-carnitine can reduce the apoptosis rate of HLE-B3 during oxidative stress through ER stress pathway. (Chin J Ophthalmol, 2018, 54: 363-368).

Effects of sevoflurane pretreatment on the apoptosis of rat H9c2 cardiomyocytes and the expression of GRP78.

The protective effect of sevoflurane on apoptosis of rat H9c2 cardiomyocytes induced by H2O2 and the effect on the expression of glucose-regulated protein 78 (GRP78) were investigated. H9c2 cells were routinely cultured and divided into the control, model and sevoflurane groups. Cells in the model group were treated with 400 µM H2O2, and cells in the sevoflurane group were pretreated with sevoflurane prior to treatment with 400 µM H2O2. MTT assay was used to assess cell viability. Annexin V-propidium iodide (AV-PI) double staining flow cytometry was used to detect apoptosis. The intracellular free Ca2+ concentration was measured by the fluorescence-based assay using Fluo-3 AM as a calcium ion fluorescence probe. The mRNA expression level of GRP78 and protein expression levels of GRP78, CHOP and caspase-12 were measured using reverse transcription quantitative polymerase chain reaction (RT-qPCR) and western blot analysis, respectively. The assays showed that after sevoflurane pretreatment the H9c2 cell viability was significantly increased, whereas the H2O2-induced apoptosis, intracellular Ca2+ concentration, mRNA expression of GRP78, and the protein expression of GRP78, CHOP and caspase-12 were all reduced. The results show that pretreatment with sevoflurane inhibited H2O2-induced apoptosis in H9c2 cells. The mechanism may be related to inhibition of the stress-related protein GRP78 expression in endoplasmic reticulum, resulting in decreased intracellular Ca2+ concentration and the downregulation of CHOP and caspase-12 expression levels.

Grape seed proanthocyanidins protect cardiomyocytes against hypoxia/reoxygenation injury by attenuating endoplasmic reticulum stress through PERK/eIF2α pathway.

The aim of the present study was to observe the protective effect of grape seed proanthocyanidins (GSPs) against endoplasmic reticulum (ER) stress‑mediated apoptosis caused by hypoxia/reoxygenation (H/R) injury in H9C2 cardiomyocytes along with its potential mechanisms. H9C2 cardiomyocytes underwent hypoxia for 3h followed by reoxygenation for 3h. Different doses of GSPs (50, 100 and 200µg/ml) were administered 30min before hypoxia. Cell viability was assessed, as well as lactic dehydrogenase (LDH) activity, cell apoptosis rate, expression levels of glucose‑regulated protein 78 (GRP78), C/EBP‑homologous protein (CHOP), protein kinase RNA‑like ER kinase (PERK), and eukaryotic translation initiation factor‑2 (eIF2α) mRNA and protein. The results revealed that GSPs improved cell viability, reduced LDH activity and reduced the apoptosis rate in cells subjected to H/R, and that the protective effect was most significant when 100µg/ml in GSPs was administered. GSPs treatment also decreased mRNA and protein expression of GRP78, CHOP, eIF2α and the level of the phosphorylated form of PERK. Furthermore, GSPs displayed a similar protective effect to that of established ER stress inhibitor 4‑phenyl butyric acid. In conclusion, the findings of this study suggest that GSPs may protect H9C2 cardiomyocytes from H/R injury by decreasing ER stress‑mediated apoptosis through the suppression of the PERK/eIF2α signaling pathway.

Effect of endoplasmic reticulum stress in trophocytes on the pathogenesis of intrahepatic cholestasis of pregnancy

Objective: To evaluate the effect of endoplasmic reticulum stress in trophocytes, in patients with intrahepatic cholestasis of pregnancy (ICP). Methods: Sixty-one pregnant women who were hospitalized in Women's Hospital, School of Medicine, Zhejiang University from January to December 2015 were recruited. Thirty-one women who were diagnosed as ICP were defined as the ICP group and 30 healthy pregnant women were defined as the control group. The localization and expression intensity of glucose regulated protein 78 (GRP-78) in placental tissues were detected by immunohistochemistry technique. Electronic microscope was used to observe ultra-microstructure change of the endoplasmic reticulum in trophocytes and cell line Swan71. Reverse transcription (RT)-PCR and western blot were used to investigate the expression of GRP-78 mRNA and protein in Swan 71 cell. Results: (1) GRP-78 protein was mainly expressed in the cytoplasm of cytotrophoblasts and syncytiotrophoblasts. The protein expression of GRP-78 in placentas of the ICP group (13.2±2.4) was significantly higher than that in the control group (7.8±1.3, P<0.01). (2) The volume of endoplasmie reticulum did not increase and the microvilli developed well, with no swelling and no expansion of endoplasmic reticulum in the control group.In the ICP group, microvilli injury, endoplasmic reticulum edema were found; the volume of endoplasmic reticulum increased, with dilation, vacuolation and significant degranulation. After treated with 100 μmol/L cholyglycine for 24 hours, universal dilatation of the endoplasmic reticulum were seen in the Swan71 cells. (3) In Swan71 cells, cholylglycine displayed a concentration-dependent up-regulation on the expression of GRP-78. The expressions of GRP-78 mRNA in 0, 25, 50, 100 μmol/L cholylglycine experimental group were 1.01±0.17, 2.17±0.16, 5.47±0.36, 5.65±0.82, respectively. The expression of GRP-78 protein in 0, 25, 50, 100 μmol/L cholylglycine experimental group were 1.01±0.04, 1.17±0.15, 1.33±0.13, 1.73±0.13, respectively. The expression of GRP-78 mRNA and protein in 100 and 50 μmol/L cholylglycine experimental group were significantly higher than 0 μmol/L (all P<0.01). Conclusion: The obvious expansion of endoplasmic reticulum and the increased expression of GRP-78 in trophocytes indicated that endoplasmic reticulum stress of trophocytes may be involved in the pathogenesis of ICP.

Therapeutic efficacy and mechanism of action of ginsenoside Rg1 in treating acute hepatic failure in mice

Objective: To examine the regulatory effect of ginsenoside Rg1 (G-Rg1) on endoplasmic reticulum stress and its effect on hepatocellular apoptosis in carbon tetrachloride (CCl(4))-induced acute liver failure (ALF). Methods: Forty healthy, adult male C57/BL mice were randomly divided into normal saline control (NS) group, G-Rg1 blank control (G-Rg1) group, CCl(4) model (CCl(4)) group, and G-Rg1 preventive treatment (CCl(4)+G-Rg1) group, and an ALF mouse model was established by CCl(4) induction. Blood and liver specimens were collected from all mice upon sacrifice at 12 hours post-intraperitoneal injection. Serum alanine aminotransferase (ALT), serum aspartate aminotransferase (AST) and total bilirubin (TBil) levels were determined using commercial test kits. The mRNA expression of glucose-regulated protein 78 (GRP78) and C/EBP homologous protein (CHOP) was measured using real-time PCR. The protein expression of GRP78, CHOP, caspase12, and caspase3 were measured by Western blot. Histological changes in the liver were assessed by hematoxylin-eosin staining, and the expression of GRP78 and caspase3 was detected by immunohistochemistry. Hepatocyte apoptosis was determined using terminal transferase dUTP nick end labeling. Quantitative data were analyzed using one-way ANOVA, and subsequent pairwise comparisons were performed using the LSD-t method. Results: Serum ALT, AST, and TBil levels in the CCl(4)+G-Rg1 group were significantly reduced compared with those in the CCl(4) group (ALT: 691.30 ± 108.06 U/L vs 980.66 ± 110.29 U/L, F = 365.07, P < 0.05; AST: 195.40 ± 15.41 U/L vs 319.44 ± 89.32 U/L, F = 115.64, P < 0.05; TBil: 1.09 ± 0.11 mg/dl vs 1.56 ± 0.12 mg/dl, F = 211.29, P < 0.05). The relative mRNA expression of GRP78 and CHOP was significantly lower in the CCl(4) + G-Rg1 group than in the CCl(4) group (P < 0.05). The relative protein expression of caspase3, GRP78, caspase12, and CHOP was significantly reduced to different extents in the CCl(4)+G-Rg1 group compared with those in the CCl4 group (P < 0.05). The CCl(4) + G-Rg1 group showed reduced liver tissue degeneration and necrosis compared with the CCl(4) group. Furthermore, the CCl(4)+G-Rg1 group showed significantly fewer brown granules in the liver than the CCl4 group (P < 0.05), indicating that G-Rg1 preventive treatment reduced CCl(4)-induced hepatocyte apoptosis. Conclusion: G-Rg1 prophylaxis can inhibit inflammation and reduce hepatocyte necrosis and apoptosis during CCl(4)-induced ALF. Its mechanism may involve the suppression of endoplasmic reticulum stress-related signaling molecules to alleviate hepatocyte endoplasmic reticulum stress and apoptosis. The results of this study suggest that G-Rg1 may inhibit liver inflammation and hepatocyte apoptosis through multiple targets to protect liver function.

Astragalus polysaccharides attenuate PCV2 infection by inhibiting endoplasmic reticulum stress in vivo and in vitro

This study explored the effects of Astragalus polysaccharide (APS) on porcine circovirus type 2 (PCV2) infections and its mechanism in vivo and vitro. First, fifty 2-week-old mice were randomly divided into five groups: a group without PCV2 infection and groups with PCV2 infections at 0, 100, 200 or 400 mg/kg APS treatments. The trial lasted for 28 days. The results showed that APS treatments at 200 and 400 mg/kg reduced the pathological injury of tissues, inhibited PCV2 infection and decreased glucose-regulated protein 78 (GRP78) and GADD153/CHOP gene mRNA and protein expression significantly (P < 0.05). Second, a study on endoplasmic reticulum stress mechanism was carried out in PK15 cells. APS treatments at 15 and 45 μg/mL significantly reduced PCV2 infection and GRP78 mRNA and protein expression (P < 0.05). Tunicamycin supplementation increased GRP78 mRNA and protein expression and significantly attenuated the APS-induced inhibition of PCV2 infection (P < 0.05). Tauroursodeoxycholic acid supplementation decreased GRP78 mRNA and protein expression and significantly inhibited PCV2 infection (P < 0.05). In addition, fifty 2-week-old mice were randomly divided into five groups: Con, PCV2, APS + PCV2, TM + PCV2 and TM + APS + PCV2. The results were similar to those in PK15 cells. Taken together, it could be concluded that APS suppresses PCV2 infection by inhibiting endoplasmic reticulum stress.

Effects of electroacupuncture combined with dietary control on liver endoplasmic reticulum stress in rats with non-alcoholic fatty liver disease

To observe the effects of electroacupuncture (EA) combined with dietary control on liver endoplasmic reticulum stress (ERS) in rats with non-alcoholic fatty liver disease (NAFLD), and to explore the action mechanism of EA on NAFLD. Sixty male SD rats were randomly divided into a common diet group (15 rats) and a model group (45 rats, fed with high-fat diet to induce NAFLD model). After model establishment, 10 rats in the common diet group were randomly selected as a control group, and 40 rats in model group were randomly divided into a high-fat diet (HFD) group, a low-fat diet (LFD) group, an EA-1 group and an EA-2 group, 10 rats in each one. From the 2nd day of model establishment, rats in the HFD group and EA-1 group were fed with high-fat diet, while rats in the LFD group and EA-2 group were fed with common diet. Rats in the EA-1 group and EA-2 group were treated with acupuncture at unilateral "Zusanli" (ST 36), "Sanyinjiao" (SP 6) and "Taichong" (LR 3), besides,"Zusanli" (ST 36) and "Sanyinjiao" (SP 6) were connected with EA. The treatment was given once a day, and two sides of acupoints were selected alternatively. Each treatment last 20 min for totally 4 weeks. The rats in the remaining groups were treated with identical fixation method. After treatment, the liver tissues of rats in each group were collected and made into ultra-thin slice to perform transmission electron microscope (TEM) on the endoplasmic reticulum morphology; western blot and real-time PCR method were applied to observe the protein and gene expression of the specific ERS protein, glucose-regulated protein 78 (GRP78). Under TEM, plenty of rough endoplasmic reticulum in alignment was observed in the cytoplasm of rats in the control group, accompanied with indistinct adhering ribosome; the rough endoplasmic reticulum in the cytoplasm in the HFD group was in expansion and obvious breakage, presenting small vacuoles in irregular arrangement; the expansion of rough endoplasmic reticulum in the LFD group and EA-1 group was relieved without appa-rent breakage and disarrangement; the rough endoplasmic reticulum in the EA-2 group was in alignment without obvious expansion. The protein expression of GRP78 was little in the control group, while the protein and mRNA expression of GRP78 were obviously increased in the remaining groups (all P<0.01). The protein and mRNA expression of GRP78 in the LFD group and EA-1 group were significantly lower than those in the HFD group (all P<0.01); those in the EA-2 group were lower than those in the LFD group and EA-1 group (all P<0.01). EA effectively improves the liver ERS in NAFLD rats, which can be one of the action mechanisms of EA on NAFLD. In addition, the efficacy is more significant with diet control.

The relationship between miRNA378, calumenin and endoplasmic reticulum stress in suckling mouse myocardium with myocarditis caused by adriamycin

To investigate the relationship between miRNA378, calumenin and endoplasmic reticulum stress in suckling mouse myocardium with myocarditis caused by adriamycin. The suckling mouse myocardium of primary culture were randomly divided into control group, adriamycin group, lentivirus infection miRNA378 over expression control group, lentivirus infection miRNA378 over expression group, lentivirus infection miRNA378 silence control group and lentivirus infection miRNA378 silence group. Firstly to identify the suckling mouse myocardium, α-SMA was monitored by immunohistochemical method, and secondly the ventricular myocytes were transfered by lentivirus plasmids. Then the expression change of miRNA378, calumenin and glucose regulated protein 78(GRP78) mRNA were detected by Quantitative Real-time PCR. Compared with the adriamycin infection group, the expression of calumenin mRNA in lentivirus infection miRNA378 over expression group was increased(P<0.01), while the expression of GRP78 mRNA was reduced(P<0.01); Compared with the adriamycin infection group, the expressions of calumenin and GRP78 mRNA in lentivirus infection miRNA378 silence group did not change insignificantly. Adriamycin injection may cause expression of calumenin in suckling mouse myocardium with myocarditis reduced, which may lead to the endoplasmic reticulum stress. This effect is related with miRNA378.

Effect of sevoflurane preconditioning on lung injury induced by limb ischemia-reperfusion in rats and the relationship with endoplasmic reticulum stress

Objective To investigate the effect of sevoflurane preconditioning on lung injury induced by limb ischemia-reperfusion in rats and the relationship with endoplasmic reticulum stress. Methods Forty-five healthy male Sprague-Dawley rats, aged 6-8 weeks, weighing 250-300 g, were randomly allocated into 3 groups(n=15 each)using a random number table: sham operation group(group S), limb ischemia-reperfusion group(group LIR), and sevoflurane preconditioning group(group SP). Limb ischemia-reperfusion was induced by clamping bilateral femoral arteries for 3 h followed by 3 h reperfusion in LIR and SP groups.In group SP, 2.5% sevoflurane was inhaled for 30 min, and 15 min later the model was established.Before ischemia and at 3 h of reperfusion(at the corresponding time point in group S), arterial blood samples were collected for blood gas analysis, and arterial oxygen partial pressure(PaO2)and arterial carbon dioxide partial pressure(PaCO2)were recorded.The rats were sacrificed at 3 h of reperfusion, and lung specimens were obtained for determination of wet to dry lung weight ratio(W/D ratio)and total lung water content(TLW)and for microscopic examination of the pathological changes, and index of quantitative evaluation for alveolar damage(IQA)was calculated.The expression of glucose-regulated protein 78(GRP78)and CCAAT/enhancer-binding protein homologous protein(CHOP)protein and mRNA in lung tissues was detected by Western blot and real-time polymerase chain reaction, respectively. Results Compared to group S, the PaO2 was significantly decreased at 3 h of reperfusion, the W/D ratio, TLW and IQA were significantly increased, the expression of GRP78 and CHOP protein and mRNA was significantly up-regulated(P 0.05). Compared to group LIR, the PaO2 was significantly increased at 3 h of reperfusion, the W/D ratio, TLW and IQA were significantly decreased, the expression of GRP78 and CHOP protein and mRNA was significantly down-regulated(P 0.05). Conclusion Sevoflurane preconditioning can ameliorate lung injury induced by limb ischemia-reperfusion in the rats, and the mechanism is related to inhibition of endoplasmic reticulum stress. Key words: Anesthetics, inhalation; Ischemic preconditioning; Extremities; Reperfusion injury; Respiratory distress syndrome, adult; Endoplasmic reticulum; Stress

Effect of Taurine on the expression of glucose regulated protein 78 and growth arrest and DNA damage-inducible protein 34 in zebrafish larvae brain after hypoxia/reoxygenation brain injury

Objective To investigate the expression of endoplasmic reticulum stress-related factors, glucose-regulated protein 78 (GRP78)and growth arrest and DNA damage-inducible protein 34 (GADD34)and neuronal apoptosis in the brain of zebrafish larvae after hypoxia/reoxygenation brain injury, and the neuroprotective role of Taurine. Methods The 5 day post-fertilization zebrafish larvae were randomly assigned to 3 groups: control group, hypoxia/reoxygenation model group (model group) and Taurine treatment group(Taurine group). According to the different time points for observation, each group was subdivided into 5 subgroups (1 h, 3 h, 6 h, 24 h, 48 h)with 100 zebrafish larvae each.The pathological changes in the brain tissues and cell apoptosis were detected by fluorescence terminal deoxynucleotidyltransferase-mediated dUTP nick end-labeling(TUNEL). The expression of GRP78 and GADD34 mRNA in the brain of zebrafish larvae were detected by real-time quantitative reverse transcription PCR(qRT-PCR). The changes in GRP78 and GADD34 protein were detected by Western blot. Results (1)TUNEL: apoptosis index(AI)was increased after hypoxia/reoxygenation, and reached the peak at 3 h in model group, the AI in Taurine group was decreased compared with that in the model group at the same time point (1 h: 22.83±1.80 vs 30.18±1.81, 3 h: 23.22±2.46 vs 42.97±4.01, 6 h: 16.80±1.69 vs 22.97±1.91, all P<0.05). (2) qRT-PCR: the expression of GRP78 and GADD34 mRNA was increased at 1 h after hypoxia/reoxygenation, and reached the peak at 3 h in the model group, the expression in Taurine group was decreased compared with that in the model group at the same time point (GRP78 mRNA: 1 h: 2.35±0.13 vs 5.36±0.35, 3 h: 3.08±0.33 vs 4.27±0.52, 6 h: 1.57±0.12 vs 3.00±0.13, all P<0.05; GADD34 mRNA: 1 h: 5.14±0.55 vs 7.45±0.67, 3 h: 2.79±0.58 vs 5.83±0.51, 6 h: 1.79±0.22 vs 3.67±0.30, all P<0.05). (3) Western blot: the expression of GRP78 and GADD34 protein was increased at 1 h, reached the peak at 6 h, but it was decreased in Taurine group (GRP78 protein: 1 h: 1.12±0.11 vs 1.37±0.13, 3 h: 0.79±0.11 vs 1.25±0.10, 6 h: 0.55±0.10 vs 1.52±0.14, all P<0.05; GADD34 protein: 1 h: 0.92±0.11 vs 1.11±0.13, 3 h: 0.96±0.11 vs 1.52±0.09, 6 h: 0.76±0.05 vs 1.89±0.06, all P<0.05). (4) The expression of GRP78 and GADD34 protein was positively correlated with AI in the model group(r=0.53, 0.56 respectively, all P<0.05). Conclusion One of neuroprotective mechanisms of Taurine against hypoxia/reoxygenation brain injury may down-regulate GRP78 and GADD34 expression. Key words: Endoplasmic reticulum stress; Hypoxic-ischemic brain damage; Glucose-regulated protein 78; Growth arrest and DNA damage-inducible protein 34; Apoptosis

Expression of glucose regulated protein 78 and the pathogenesis of gestational diabetes mellitus

To investigate the relationship between the expression of glucose regulated protein 78 (GRP78) in the placental trophoblast cells and the pathogenesis of gestational diabetes mellitus (GDM). All the patients were recruited from Qingdao Municipal Hospital from May 2013 to May 2014. Among them, fifty women with GDM were assigned to the GDM group, and fifty healthy women were defined as the control group. All of them received cesarean section because of breech presentation, contracted pelvis, scarred uterus or on mother's demand. Real-time PCR was conducted to analyze the expression of GRP78 mRNA in the trophoblasts. Immunohistochemistry was performed to detect the localization of GRP78 protein in the placentasl trophoblast cells. (1) GRP78 mRNA expressed in the cytoplasm of trophoblasts of both the GDM group and the control group. The GRP78 mRNA levels in the GDM group and the control group were 15.6±0.4 and 6.0±0.7, respectively. The relative expression level of GRP78 mRNA in the GDM group was 2.6 times of that in the control group, with statistically significant difference (P<0.01). (2) The expression of GRP78 protein was found in the cytoplasm of the trophoblasts of the GDM group. It showed in deep, light brown or yellow after staining, according to the expression degree. The expression of GRP78 protein was also found in the cytoplasm of the trophoblasts of the control group, but it mainly showed yellow color (38/50). The strong positive rate of GRP78 protein in the GDM group (96%, 48/50) was higher than that in the control group (22%, 11/50; P<0.01). The expression of GRP78 increased in the placental trophoblast cells of GDM patients. It might suggest that GRP78 had some effect on the pathogenesis of GDM.

Involvement of GRP78 in the Resistance of Ovarian Carcinoma Cells to Paclitaxel.

Glucose regulated protein 78 (GRP78) is a type of molecular chaperone. It is a possible candidate protein that contributes to development of drug resistance. We first examined the involvement of GRP78 in chemotherapy-resistance in human ovarian cancer cell. The expression of GRP78 mRNA and protein were examined by RT-PCR and western blotting, respectively, in human ovarian cancer cells line (HO-8910). Sensitivity of HO-8910 to paclitaxel was determined with methyl thiazolyl tetrazolium (MTT). Suppression of GRP78 expression was performed using specific small-interfering RNA (siRNA) in HO-8910 cells, and cell apoptosis was assessed by flow cytometry. Statistical analysis was performed using the SPSS 15.0 statistical package. HO-8910 cells, with high basal levels of GRP78, exhibited low sensitivity to paclitaxel. The mRNA and protein levels of GRP78 were dramatically decreased at 24h, 48h and 72h after transfection and the sensitivity to paclitaxel was increased when the GRP78 gene was disturbed by specific siRNA transfection. The results suggested that high GRP78 expression might be one of the molecular mechanisms causing resistance to paclitaxel, and therefore siRNA of GRP78 may be useful in tumor-specific gene therapy for ovarian cancer.

Preconditioning With Tauroursodeoxycholic Acid Protects Against Contrast-Induced HK-2 Cell Apoptosis by Inhibiting Endoplasmic Reticulum Stress.

To investigate whether tauroursodeoxycholic acid (TUDCA) could attenuate contrast media (CM)-induced renal tubular cell apoptosis by inhibiting endoplasmic reticulum stress (ERS), we exposed HK-2 cells to increasing doses of meglumine diatrizoate (20, 40, and 80 mg I/mL) for 2 to 16 hours, with/without TUDCA preconditioning for 24 hours. Cell viability test, Hoechst 33258 staining, and flow cytometry were used to detect meglumine diatrizoate-induced cell apoptosis, while real-time polymerase chain reaction and Western blot analysis were used to measure the expressions of ERS markers of glucose-regulated protein 78 (GRP78), activating transcription factor 4 (ATF4), and the apoptosis-related marker of caspase 12. Cell apoptosis and messenger RNA (mRNA) expression of GRP78 (P = .005), ATF4 (P = .01), and caspase 12 (P = .001) were significantly higher in the CM 4 hours group than the control as well as the protein expressions. The TUDCA preconditioning reduced the mRNA expression of GRP78, ATF4, and caspase 12 in the CM 4 hours groups (P = .009, .019, and .003, respectively) as well as the protein expression. In conclusion, TUDCA could protect renal tubular cells from meglumine diatrizoate-induced apoptosis by inhibiting ERS.

A study of lymphocyte apoptosis and endoplasmic reticulum stress in the development of sepsis and their association with outcome in septic patients

To investigate the role of lymphocyte apoptosis and endoplasmic reticulum stress (ERS) on the development of sepsis and their association with the prognosis of sepsis patients. A prospective cohort study was conducted. Seventy septic patients admitted to intensive care unit (ICU) of Shanghai East Hospital of Tongji University were enrolled. Blood samples were collected on days 1, 3 and 7 to measure percentage of circulating apoptotic lymphocyte with flow cytometry analysis. The relative expressions of endoplasmic reticulum specific glucose regulated protein 78 (GRP78) mRNA and transcription factor CHOP mRNA were measured by real-time reverse transcription-polymerase chain reaction (RT-PCR). The correlation between CHOP mRNA expression and percentage of circulating apoptotic lymphocyte was analyzed by Spearman relative analysis. The patients were divided into death (n = 23) and survival subgroups (n = 47). Twenty healthy volunteers during the same period were selected as the healthy control group. (1) Rate of lymphocyte apoptosis: compared with healthy control group [(2.86±0.66)%], septic patients, either survival or death subgroup, exhibited higher rate of lymphocyte apoptosis on days 1, 3 and 7 [survival subgroup: (12.44±4.43)%, (8.57±3.38)%, (6.78±3.35)%; death subgroup: (14.42±2.01)%, (11.32±2.53)%, (8.87±3.62)%, all P < 0.01], and it was obvious on day 1, and the phenomenon became less marked gradually. The rate of circulating apoptotic lymphocytes did not differ between the death and survival subgroups on day 1, but there was a significant difference in the rate on day 3 and day 7 (both P < 0.05). (2) The expression of CHOP mRNA (2(-ΔΔCt)): compared with that in healthy controls [(2.56±1.09)×10-3], CHOP mRNA expression was increased on days 1, 3 and 7 in septic patients [survival subgroup: (5.83±1.96)×10(-3), (4.24±1.60)×10(-3), (4.15±1.64)×10(-3), death subgroup: (37.20±20.70)×10(-3), (18.80±13.90)×10(-3), (9.28±7.78)×10(-3), all P < 0.01], and it was more obvious in the death subgroup, as it was increased by 6.38, 4.43, and 2.24 folds (P values was 0.000, 0.000, and 0.001), but it decreased rapidly in death subgroup. (3) The expression of GRP78 mRNA (2(-ΔΔCt)): compared with healthy controls [(3.31±2.04)×10(-3)], the expression of GRP78 mRNA in both survival and death subgroups increased in septic patients on day 1 [(5.83±2.00)×10-3, (11.30±6.48)×10(-3), both P < 0.01], and they decreased subsequently. The expression of GRP78 mRNA in the survival subgroup declined to the levels of the healthy control group on day 3 and day 7 [3 days: (3.99±1.60)×10(-3), 7 days: (3.30±1.35)×10(-3), both P > 0.05], and GRP78 mRNA expression in the death subgroup was gradually lowered, but it was still higher than that in the healthy control group [3 days: (7.27±3.64)×10(-3), 7 days: (5.23±1.94)×10(-3), both P < 0.01]. (4) Spearman relative analysis showed that the expression of CHOP mRNA was positively correlated with the rate of lymphocyte apoptosis (r = 0.414, P = 0.000). The increase in the rate of lymphocyte apoptosis and activation of ERS play an important role in the development of sepsis, and it is associated with worse outcome in the septic patients.