scholarly journals High doses of dexamethasone induce endoplasmic reticulum stress-mediated apoptosis by promoting calcium ion influx-dependent CHOP expression in osteoblasts

Author(s):  
Yunshan Guo ◽  
Dingjun Hao ◽  
Huimin Hu

Abstract Background The long-term use of dexamethasone (Dex), a well-known immunosuppressant, leads to an imbalance in bone metabolism and rapid decline of bone mineral density due to apoptosis of osteoblasts. The molecular mechanisms by which Dex induces osteoblast apoptosis remain unclear. Materials and methods MC3T3-E1 cells were treated with 0, 10−8, 10−6, and 10−4 M Dex for 24 h. ATF6, phosphorylated PERK, PERK, phosphorylated IRE1, and IRE1 expression, cell apoptosis, and caspase-12 and caspase-3 activity were measured. CHOP expression and calcium ion influx rate were measured in cells treated with 0 and 10−4 M Dex for 24 h. The effect of 2-APB treatment was assessed in cells treated with 0 or 10−4 M Dex. Results Levels of ATF6 and phosphorylated PERK and IRE1 increased in a dose-dependent manner in MC3T3-E1 cells treated with 10−8, 10−6, and 10−4 M Dex, compared to the control group (P < 0.05). Cells treated with 10−6 and 10−4 M Dex had significantly increased apoptotic rates and caspase-12 and caspase-3 activities (P < 0.05). Cells treated with 10−4 M Dex had significantly increased CHOP levels and calcium ion influx rates (P < 0.05). Combined treatment with 10−4 M Dex and 2-APB abrogated the observed increases in cell apoptosis and caspase-12 and caspase-3 activities (P < 0.05). Conclusions High doses of Dex induce CHOP expression by promoting calcium ion influx-dependent induction of ATF6, phosphorylated PERK and phosphorylated IRE1, which induce endoplasmic reticulum stress-mediated apoptosis in osteoblasts. 2-APB protects the osteoblasts from the effects of Dex, preventing endoplasmic reticulum stress-mediated apoptosis.

2021 ◽  
Author(s):  
Yunshan Guo ◽  
Dingjun Hao

Abstract Background: The molecular mechanisms by which dexamethasone (Dex) induces apoptosis in osteoblasts remain unclear.Materials and Methods: MC3T3-E1 cells were treated with 0, 10-8, 10-6, and 10-4 M Dex for 24 h. The expression of ATF6, and phosphorylated PERK and IRE1, cell apoptosis, and the activity of caspase-12 and caspase-3 were measured. The expression of CHOP and the rate of influx of calcium ions were also measured in cells treated with 0 and 10-4 M Dex for 24 h. The effect of 2-APB treatment was assessed in cells treated with 0 or 10-4 M Dex.Results: The levels of ATF6 and phosphorylated PERK and IRE1 increased in a dose-dependent manner in MC3T3-E1 cells treated with 10-8, 10-6, and 10-4 M Dex, compared to in cells treated with 0 M Dex (P <0.05). Cells treated with 10-6 and 10-4 M Dex had significantly increased cell apoptosis rates and caspase-12 and caspase-3 activity compared to the control (P <0.05). Cells treated with 10-4 M Dex had significantly increased levels of CHOP and calcium ion influx rates compared to in the control (P <0.05). Combined treatment with 10-4 M Dex and 2-APB abrogated the observed increases in cell apoptosis and the activity of caspase-12 and caspase-3 (P>0.05). Conclusion: High doses of Dex induce endoplasmic reticulum stress-mediated apoptosis by promoting calcium ion influx-dependent expression of CHOP, and the activation of caspase-12 and caspase-3 in osteoblasts. Combined treatment with 2-APB protects the cells from the effects of Dex, preventing endoplasmic reticulum stress-mediated apoptosis.


2020 ◽  
Vol 2020 ◽  
pp. 1-7 ◽  
Author(s):  
Shen Yan ◽  
Liu Yingchao ◽  
Wang Zhangliu ◽  
Ruan Xianli ◽  
Li Si ◽  
...  

The purpose of this study was to verify the effect of berberine (BBR) on endoplasmic reticulum stress (ERS) and apoptosis of intestinal epithelial cells (IECs) in mice with ulcerative colitis (UC). BALB/c mice were randomly divided into five groups as follows: blank control, model, and low-, medium-, and high-dose BBR. A dextran sodium sulfate- (DSS-) induced model of UC was prepared, and the low-, medium-, and high-dose BBR groups were simultaneously gavaged with a BBR suspension for 7 d. Disease activity index (DAI) was assessed, and tissue damage index (TDI) was assessed from colon samples after the last administration. TUNEL assays were used to detect apoptosis of IECs. Immunohistochemistry and/or real-time PCR were applied to determine the expression of GRP78, caspase-12, and caspase-3. In all BBR treatment groups, clinical symptoms of colitis and histopathological damage were significantly reduced. The high-dose BBR group exhibited particularly pronounced decrease (p<0.01) in both DAI (0.48 ± 0.36) and TDI (1.62 ± 0.64) relative to the model group (1.50 ± 0.65 and 3.88 ± 0.04, respectively). In colon tissues of the model group, the number of apoptotic IECs was significantly increased; the expression of GRP78, caspase-12, and caspase-3 proteins was significantly increased; and the expression of the GRP78 mRNA was upregulated. In low-, medium-, and high-dose BBR groups, the number of apoptotic IECs was significantly reduced. Moreover, GRP78 and caspase-3 expression levels were significantly decreased in the medium- and high-dose BBR groups, caspase-12 expression was significantly decreased in the high-dose BBR group, and the GRP78 mRNA expression level was significantly decreased in the high-dose BBR group. BBR can effectively reduce the rate of IEC apoptosis in UC mice and alleviate the inflammatory response in the colon. The underlying mechanism seems to involve ERS modulation and inhibition of ERS-mediated activation of the caspase-12/caspase-3 apoptosis signaling pathway.


2017 ◽  
Vol 44 (6) ◽  
pp. 2407-2421 ◽  
Author(s):  
Yanhua Cui ◽  
Lipeng Ren ◽  
Bo Li ◽  
Jia Fang ◽  
Yuanxin Zhai ◽  
...  

Background/Aims: Busulfan is commonly used for cancer chemotherapy. Although it has the advantage of increasing the survival rate of patients, it can cause male infertility via damaging the testes and reducing sperm counts. Therefore, the underlying mechanism should be explored, and new agents should be developed to protect the male reproductive system from busulfan-induced damage. Endoplasmic reticulum stress (ERS) is considered a key contributor to numerous pathologies. Despite several studies linking ERS to toxicants, studies have yet to determine whether ERS is a contributing factor to busulfan-induced testicular damage. Melatonin is a well-known broad-spectrum antioxidant, anti-inflammatory and antitumour agent, but the effects of melatonin on busulfan-induced ERS in mouse testes damage are less documented. Methods: The effects of melatonin were measured by immunofluorescence staining, Western blot, qRT-PCR analysis and flow cytometry assay. The underlying mechanism was investigated by measuring ERS. Results: We found that ERS was strongly activated in mouse testes (in vivo) and the C18-4 cell line (in vitro) after busulfan administration. ERS-related apoptosis proteins such as caspase-12, CHOP and caspase-3 were activated, and the expression of apoptotic proteins such as P53 and PUMA were upregulated. Furthermore, we investigated whether melatonin reduced the extent of damage to mouse testes and improved the survival rates of busulfan-treated mice. When exploring the underlying mechanisms, we found melatonin could counteract ERS by decreasing the expression levels of the ERS markers GRP78, ATF6, pIRE1 and XBP1 in mouse testes and mouse SSCs (C18-4 cells). Moreover, it blocked the activation of ERS-related apoptosis proteins caspase-12, CHOP and caspase-3 and suppressed P53 and PUMA expression stimulated by busulfan both in vivo and in vitro. Conclusion: Our results demonstrate that ERS is an important mediator for busulfan-induced apoptosis. The attenuation of ERS by melatonin can prevent busulfan-treated SSCs apoptosis and protect busulfan-treated testes from damage. Thus, this study suggests that melatonin may alleviate the side effects of busulfan for male patients during clinical treatment.


2021 ◽  
Author(s):  
Yanqing Sun ◽  
Wei Shi ◽  
Bo Yuan ◽  
Zhiwei Wang ◽  
Shengyuan Zhou ◽  
...  

Abstract Background: This study aims to explore the protective effect of hydrogen against oxygen-glucose-serum deprivation/restoration (OGSD/R)-induced PC12 cell apoptosis in vitro and the possible underlying mechanism. Methods: A normal control (NC) group was set where PC12 cells were cultured normal, while a positive control (PC) group, where PC12 cells were exposed to OGSD 12h/R1h without intervention, and a hydrogen intervention (HI) group, where PC12 cells were exposed to OGSD 12h/R1h plus HI, were conducted at the same time. At OGSD 12h/R 1h, cells were DAPI stained to detect viability and changes in the expression of apoptosis-associated proteins caspase-3, caspase-12 and CHOP/GADD153, and the endoplasmic reticulum-related signaling pathway protein PERK-eIF2α-ATF4. At the same time, the effect of HI was observed. Results: The result revealed that compared with NC group, cell apoptosis was more severe and cell viability was reduced significantly in PC group, while cell apoptosis was ameliorated and cell viability was increased significantly in HI as compared with PC group. In addition, the content of caspase-3 and caspase-12 in HI group was decreased significantly as compared with that in PC group. During this process, the endoplasmic reticulum-related signaling pathway protein PERK-eIF2α-ATF4 was activated. In HI group, the expression of this protein was decreased and cell viability was increased significantly as compared with those in PC group. Conclusions: Hydrogen was able to inhibit OGSD/R-induced PC12 cell apoptosis and exert a protective effect against ischemia-repurfusion injury (IRI) to nerve cells, probably through inhibiting the endoplasmic reticulum-related signaling pathway protein.


2020 ◽  
Vol 2020 ◽  
pp. 1-8
Author(s):  
Tianwei Lan ◽  
Qian Yu

The herb Cistanche deserticola has some myocardial protective effects. This study attempted to explain the mechanism by which PhG-RE protects myocardial cells and verify if this protection occurs through regulating the apoptosis mechanism associated with endoplasmic reticulum stress (ERS). Rat myocardial cells were exposed to 150 μg·mL−1 PhG-RE for 24 h and then to 100 μmol·mL−1 H2O2 for 18 h to induce ERS and establish a cell damage model. Thapsigargin (TG), a specific ERS activator, and 4-phenylbutyric acid (4-PBA), an ERS inhibitor, were used to validate the accuracy of the experiment. Our results demonstrated that PhG-RE significantly improved cell viability, protected cells, and reduced cell damage and apoptosis. PhG-RE played a role similar to that of the ERS inhibitor 4-PBA in protecting myocardial cells against apoptosis and damage induced by ER stress. Furthermore, PhG-RE significantly attenuated the mRNA expression of the ERS-associated apoptotic factors GRP78, CHOP, and Caspase-12 and the protein expression of the ERS-associated apoptotic factors GRP78, CHOP, Caspase-12, and p-JNK. Taken together, these findings suggest that PhG-RE can effectively protect myocardial cells and reduce cell apoptosis and damage, which may be related to the regulation of ERS-associated apoptosis.


2019 ◽  
Vol 39 (8) ◽  
Author(s):  
Jiangwei Chen ◽  
Zunwen Lin ◽  
Kui Deng ◽  
Bin Shao ◽  
Dong Yang

Abstract Background: Intervertebral disc degeneration is a common degenerative disease. The present study aimed to explore the role and mechanism of tension-induced endoplasmic reticulum stress in intervertebral disc degeneration. Methods: Intervertebral disc degeneration models of SD rat were analyzed for apoptosis, the expression of Poly(ADP-ribose) polymerase (PARP), Caspase-12, Caspase-3, LC3, Beclin-1 and CHOP using immunohistochemistry, qPCR and Western blot analysis. Annulus fibrosus cells of intervertebral disc were isolated, subjected to cyclic deformation stress and analyzed for ROS and apoptosis, lysosome activity and expression of genes. The cells were knockdown with siRNA or treated with endoplasmic reticulum stress inhibitor 4-PBA and assayed for ROS, apoptosis, lysosome activity and gene expression. Results: Compared with the controls, intervertebral disc degeneration was observed through X-rays examinations and HS staining. Apoptosis and expression of PARP, Caspase-12, Caspase-3, LC3, Beclin-1 and CHOP were significantly increased in the intervertebral disc tissue of the models. In mechanic mimic experiments, the primary annulus fibrosus cells were subjected to 18% cyclic deformation, ROS and apoptosis as well as the activity of lysosome were increased. Similarly, the expression of PARP, Caspase-12, Caspase-3, LC3, Beclin-1 and CHOP was also increased significantly after deformation treatment. On other hand, when the cells were treated with 9 mM 4-PBA and/or CHOP-siRNA4, the apoptosis rate, ROS level, lysosome activity and expression of PARP, Caspase-12, Caspase-3, LC3, Beclin-1 and CHOP were significantly reduced. Conclusions: Autophagy reaction mediated by endoplasmic reticulum stress plays important rale in tension-induced intervertebral disc degeneration. Intervertebral disc degeneration likely results from interactions between autophagy, apoptosis and reticulum stress, and is ROS-dependent.


2018 ◽  
Vol 2018 ◽  
pp. 1-13 ◽  
Author(s):  
Jinfan Tian ◽  
Yanfei Liu ◽  
Yue Liu ◽  
Keji Chen ◽  
Shuzheng Lyu

Diabetes was induced in high-fat diet-fed ApoE−/− mice via administration of low-dose streptozotocin (STZ) for five days. Mice were then treated with GBE (200 or 400 mg/kg) by gastric gavage daily for 12 weeks. Mice in the untreated diabetic group received saline instead, and nondiabetic C57BL/6J mice served as controls. Collagen І and ІІІ mRNA expression was measured by real-time PCR. TNF-α, IL-1β mRNA levels, and NF-κB expression were determined to analyze intramyocardial inflammation. Hallmarks of endoplasmic reticulum stress- (ERS-) related apoptosis pathways, including phosphorylated c-Jun N-terminal kinase (p-JNK), C/EBP homologous protein (CHOP), caspase-12, and cleaved caspase-3, were analyzed by Western blotting. Diabetic ApoE−/− myocardial injury was associated with increased cardiomyocyte apoptosis (increased expression of p-JNK, CHOP, caspase-12, and cleaved caspase-3), interstitial fibrosis (increased mRNA levels of collagen І and ІІІ), and inflammation (increased mRNA levels of TNF-α and IL-1β, and NF-κB expression). GBE at 200 and 400 mg/kg/day significantly attenuated cardiomyocyte apoptosis, collagen deposition, and inflammation in diabetic mice via inhibition of the p-JNK, CHOP, and caspase-12 pathways. Serum levels of the proinflammatory cytokines (IL-6, IL-1β, and TNF-α), blood glucose, and lipid profiles were also regulated by GBE treatment. GBE might be beneficial in the treatment of diabetic myocardial injury.


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