OBJECTIVES: To explore the effects of cannabidiol on endoplasmic reticulum stress and neuronal apoptosis in rats with multiple concussions (MCC). METHODS: SD rats were randomized into sham group, MCC group, 1% tween20 (TW) treatment group, and low-dose (10 mg/kg) and high-dose (40 mg/kg) cannabidiol treatment groups. In all but the sham group, MCC models were established using a metal pendulum percussion device, after which the rats received daily intraperitoneal injections of the corresponding agents for 2 weeks. The expressions of PERK, eIF2α, ATF4, CHOP, TRIB3, p-Akt and pro-caspase-3 in the brain tissue of the rats were detected with qRT-PCR, Western blotting and immunofluorescence staining. The core targets of cannabidiol in treatment of traumatic brain injury (TBI) were identified by network pharmacology analysis, and molecular docking was carried out to simulate the interaction of cannabidiol with the factors related to endoplasmic reticulum stress and apoptosis. RESULTS: Compared with the sham-operated rats, the rat models of MCC showed significantly increased mRNA expressions of PERK, eIF2α and CHOP and protein expressions of PERK, eIF2α, ATF4, CHOP, TRIB3, p-AKT and pro-caspase-3 in the cerebral cortex. CBD treatment, especially at the high dose, obviously increased the expression of p-Akt and lowered the expression levels of the other factors tested in the rat models. Network pharmacology analysis indicated interactions of the core targets of CBD with the factors related to endoplasmic reticulum stress and TBI, and molecular docking study showed a high binding energy of CBD with multiple factors pertaining to endoplasmic reticulum stress and apoptosis. CONCLUSIONS MCC induce endoplasmic reticulum stress and apoptosis in rat brain tissues, for which CBD, especially at a high dose, provides neuroprotective effects by inhibiting endoplasmic reticulum stress and cell apoptosis.
Animals ; Endoplasmic Reticulum Stress/drug effects* ; Apoptosis/drug effects* ; Rats, Sprague-Dawley ; Activating Transcription Factor 4/metabolism* ; Transcription Factor CHOP/metabolism* ; Rats ; Eukaryotic Initiation Factor-2/metabolism* ; Signal Transduction/drug effects* ; eIF-2 Kinase/metabolism* ; Cannabidiol/pharmacology* ; Neurons/metabolism* ; Brain Concussion/metabolism* ; Male ; Molecular Docking Simulation

Up-frameshift 1 (UPF1), as the most critical factor in nonsense-mediated messenger RNA (mRNA) decay (NMD), regulates tumor-associated molecular pathways in many cancers. However, the role of UPF1 in lung adenocarcinoma (LUAD) amino acid metabolism remains largely unknown. In this study, we found that UPF1 was significantly correlated with a portion of amino acid metabolic pathways in LUAD by integrating bioinformatics and metabolomics. We further confirmed that UPF1 knockdown inhibited activating transcription factor 4 (ATF4) and Ser51 phosphorylation of eukaryotic translation initiation factor 2α (eIF2α), the core proteins in amino acid metabolism reprogramming. In addition, UPF1 promotes cell proliferation by increasing the amino-acid levels of LUAD cells, which depends on the function of ATF4. Clinically, UPF1 mRNA expression is abnormal in LUAD tissues, and higher expression of UPF1 and ATF4 was significantly correlated with poor overall survival (OS) in LUAD patients. Our findings reveal that UPF1 is a potential regulator of tumor-associated amino acid metabolism and may be a therapeutic target for LUAD.
Activating Transcription Factor 4/genetics* ; Adenocarcinoma of Lung ; Amino Acids ; Cell Proliferation ; Eukaryotic Initiation Factor-2 ; Humans ; Lung Neoplasms ; RNA Helicases/metabolism* ; RNA, Messenger/metabolism* ; Trans-Activators/metabolism*

Animals ; Cell Line ; Diabetic Nephropathies ; metabolism ; Epithelial-Mesenchymal Transition ; drug effects ; Eukaryotic Initiation Factor-2 ; metabolism ; Glucose ; pharmacology ; Humans ; Kidney ; drug effects ; metabolism ; pathology ; Kidney Tubules, Proximal ; drug effects ; metabolism ; Rats ; Signal Transduction ; drug effects

OBJECTIVEPERK/eIF2α/CHOP is a major signaling pathway mediating endoplasmic reticulum (ER) stress related with atherosclerosis. Oxidized LDL (ox-LDL) also induces endothelial apoptosis and plays a vital role in the initiation and progression of atherosclerosis. The present study was conducted to explore the regulatory effect of ox-LDL on PERK/eIF2α/CHOP signaling pathway in vascular endothelial cells.

METHODSThe effects of ox-LDL on PERK and p-eIF2α protein expression of primary human umbilical vein endothelial cells (HUVECs) were investigated by Western blot analysis. PERK gene silencing and selective eIF2α phosphatase inhibitor, salubrinal were used to inhibit the process of ox-LDL induced endothelial cell apoptosis, caspase-3 activity, and CHOP mRNA level.

RESULTSOx-LDL treatment significantly increased the expression of PERK, PERK-mediated inactivation of eIF2α phosphorylation, and the expression of CHOP, as well as the caspase-3 activity and apoptosis. The effects of ox-LDL were markedly decreased by knocking down PERK with stable transduction of lentiviral shRNA or by selective eIF2α phosphatase inhibitor, salubrinal.

CONCLUSIONThis study provides the first evidence that ox-LDL induces apoptosis in vascular endothelial cells mediated largely via the PERK/eIF2α/CHOP ER-stress pathway. It adds new insights into the molecular mechanisms underlying the pathogenesis and progression of atherosclerosis.

Apoptosis ; Endoplasmic Reticulum Stress ; Eukaryotic Initiation Factor-2 ; genetics ; metabolism ; Human Umbilical Vein Endothelial Cells ; metabolism ; Humans ; Lipoproteins, LDL ; genetics ; metabolism ; Signal Transduction ; Transcription Factor CHOP ; genetics ; metabolism ; eIF-2 Kinase ; genetics ; metabolism

BACKGROUNDPrevious studies have indicated that endoplasmic reticulum stress participates in and mediates liver injury and apoptosis in brain-dead (BD) rats. In this study, we observed the effect of salubrinal (Sal, Sigma, USA) on liver cells in BD rats and explored its relevant mechanisms.

METHODSThirty Sprague-Dawley rats were equally randomized into three groups: BD group, Sal group, and DMSO group. The BD models were established by increasing intracranial pressure in a modified, slow, and intermittent way. In the drug groups, Sal was administered 1 h before the induction of BD. After modeling was completed, the blood and liver samples were harvested. CHOP and Caspase-12 mRNA expression was detected using quantitative polymerase chain reaction. PKR-like ER kinase (PERK), P-eukaryotic translation initiation factor 2α (eIF2α), eIF2α, CHOP and caspase-12 expression was detected using western blotting (WB). CHOP and caspase-12 distribution and expression in liver tissues were determined using immunohistochemistry (IHC). Alanine aminotransferase and aspartate aminotransferase level were detected using an automatic biochemical analyzer. Hepatic cell apoptosis was detected using TUNEL. The results were analyzed using Quantity-one v4.62 software (Bio-Rad, USA).

RESULTSCHOP and caspase-12 expression and PERK, eIF2α, and P-eIF2α protein expression showed no significant difference between BD group and DMSO group. Compared with BD group, Sal group had a significantly higher P-eIF2C level and a lower P-PERK level 2 h and 6 h after BD (P < 0.05). However, eIF2α expression showed no significant difference (P > 0.05). After the Sal treatment, CHOP and caspase-12 mRNA expression significantly decreased 4 h after BD (P < 0.05). WB and IHC indicated that CHOP and caspase-12 expression also significantly decreased after Sal treatment. Sal was associated with improved liver function and decreased hepatic cell apoptosis.

CONCLUSIONSSal can significantly reduce apoptosis in hepatic cells of BD rats. This protective effect may be achieved via the PERK-eIF2α signaling pathway.

Animals ; Apoptosis ; drug effects ; Blotting, Western ; Brain Death ; metabolism ; Caspase 12 ; genetics ; metabolism ; Cinnamates ; Disease Models, Animal ; Endoplasmic Reticulum Stress ; drug effects ; Eukaryotic Initiation Factor-2 ; genetics ; metabolism ; Immunohistochemistry ; Liver ; drug effects ; injuries ; Male ; Rats ; Rats, Sprague-Dawley ; Real-Time Polymerase Chain Reaction ; Thiourea ; analogs & derivatives ; Transcription Factor CHOP ; genetics ; metabolism

5-Hydroxymethylfurfural (5-HMF), a water-soluble compound extracted from wine-processed Fructus corni, is a novel hepatic protectant for treating acute liver injury. The present study was designed to investigate the protective effect of 5-HMF in human L02 hepatocytes injured by D-galactosamine (GalN) and tumor necrosis factor-α (TNF-α) in vitro and to explore the underlying mechanisms of action. Our results showed that 5-HMF caused significant increase in the viability of L02 cells injured by GalN/TNF-α, in accordance with a dose-dependent decrease in apoptotic cell death confirmed by morphological and flow cytometric analyses. Based on immunofluorescence and Western blot assays, we found that GalN/TNF-α induced ER stress in the cells, as indicated by the disturbance of intracellular Ca(2+) concentration, the activation of protein kinase RNA (PKR)-like ER kinase (PERK), phosphorylation of eukaryotic initiation factor 2 alpha (eIF2α), and expression of ATF4 and CHOP proteins, which was reversed by 5-HMF pre-treatment in a dose-dependent manner. The anti-apoptotic effect of 5-HMF was further evidenced by balancing the expression of Bcl-2 family members. In addition, the knockdown of PERK suppressed the expression of phospho-PERK, phospho-eIF2α, ATF4, and CHOP, resulting in a significant decrease in cell apoptosis after the treatment with GalN/TNF-α. 5-HMF could enhance the effects of PERK knockdown, protecting the cells against the GalN/TNF-α insult. In conclusion, these findings demonstrate that 5-HMF can effectively protect GalN/TNF-α-injured L02 hepatocytes against ER stress-induced apoptosis through the regulation of the PERK-eIF2α signaling pathway, suggesting that it is a possible candidate for liver disease therapy.
Apoptosis ; drug effects ; Cornus ; chemistry ; Endoplasmic Reticulum Stress ; drug effects ; Eukaryotic Initiation Factor-2 ; genetics ; metabolism ; Furaldehyde ; analogs & derivatives ; pharmacology ; Galactosamine ; metabolism ; Hepatocytes ; cytology ; drug effects ; metabolism ; Humans ; Liver ; cytology ; drug effects ; metabolism ; Plant Extracts ; pharmacology ; Protective Agents ; pharmacology ; Signal Transduction ; drug effects ; Tumor Necrosis Factor-alpha ; genetics ; metabolism ; eIF-2 Kinase ; genetics ; metabolism

OBJECTIVETo investigate whether the phosphorylation (functionally inhibitive) of eukaryotic initiation factor 2-alpha (eIF2-a) affects the molecular mechanism of cisplatin-induced cellular apoptosis in human hepatocellular carcinoma (HCC).

METHODSThe human HCC cultured cell lines SMMC-7221 and HepG2 were treated with cisplatin alone (controls; 24 h) or in combination with pre-transfection of a dominant-negative eIF2-a mutant (eIF2aS51A) or pre-exposure to an eIF2-a-specific phosphatase inhibitor (salubrinal) to decrease or increase the phosphorylation level, respectively. Changes in expression of apoptosis markers were quantitatively and qualitatively assessed by flow cytometry and western blot analysis. The significance of differences among groups was assessed by analysis of variance testing and of differences between groups was assessed by t-test.

RESULTSCisplatin treatment induced the appropriate functional-inhibitive phosphorylation of eIF2-a on serine 51. Cisplatin treatment (10 mg/ml) induced significant apoptosis in the eIF2aS51A pre-transfected SMMC-7721 (control: 21.7 +/- 1.5% vs. 50.7 +/- 2.1%, t = 19.454, P less than 0.05) and HepG2 (21.0 +/- 1.0% vs. 57.3 +/- 2.1%, t = 27.250, P less than 0.05). Salubrinal pre-treatment significantly inhibited the cisplatin (15 mg/ml)-induced apoptosis in SMMC-7721 (control: 50.3 +/- 2.5% vs. 16.3 +/- 2.1%, t = 18.031, P less than 0.05) and HepG2 (42.0 +/- 2.6% vs. 12.0 +/- 2.0%, t = 15.667, P less than 0.05).

CONCLUSIONPhosphorylation of eIF2-a may act to inhibit cisplatin-induced apoptosis of HCC.

Apoptosis ; drug effects ; Carcinoma, Hepatocellular ; Cell Line, Tumor ; Cisplatin ; pharmacology ; Eukaryotic Initiation Factor-2 ; metabolism ; Humans ; Liver Neoplasms ; Phosphorylation

OBJECTIVETo explore attenuation and mechanism of endoplasmic reticulum stress (ERS)-mediated hepatocyte apoptosis in rats with alcohol-induced liver injury by Qinggan Huoxue Recipe (QGHXR) and its disassembled formulas (Qinggan Recipe and Huoxue Recipe respectively).

METHODSA rat model of chronic alcoholic liver injury was successfully established using a compound reagent of alcohol, corn oil, and pyrazol. The modeled rats were randomly divided into the model group, the QGHXR group, the Qinggan Recipe (QGR) group, and the Huoxue Recipe group (HXR). The CCl4 control group and the normal control group were also set up. There were ten rats in each group. All rats of modeled groups were gastrogavaged with alcohol compound reagent every morning. Rats in the QGHXR group (at the daily dose of 9. 5 g/kg, QGR group (at the daily dose of 3.0 g/kg), and HXR group (at the daily dose of 6.5 g/kg) were administered with corresponding medicines by gastrogavage every afternoon. Equal volume of normal saline was given to rats of the model group by gastrogavage. CCl4 was intraperitoneally injected at the dose of 0.3 mL/kg to rats in the CCl4 control group, once per week. Normal saline was given to rats in the normal control group by gastrogavage. The treatment was lasted for two weeks. Pathological changes of the liver were observed by histopathology. Serum total homocysteine (tHCY) level was detected by ELISA. The hepatocyte apoptosis rate was detected using flow cytometry. The gene and protein expressions of eukaryotic translation initiation factor 2 alpha (elF-2alpha), phosphorylation elF-2alpha (pelF-2alpha), glucose-regulated protein 78 (GRP78), and Caspase-3 in the liver were examined using Real-time PCR and Westen blot respectively.

RESULTSCompared with the normal control group, typical pathological changes of chronic alcoholic liver injury such as steatosis, inflammation, and even fibrosis occurred in model rats. The hepatocyte apoptosis obviously increased, with the apoptosis rate reaching the five-fold of that in normal rats. Besides, early apoptosis dominated. The serum tHCY level significantly increased. The expressions of p-elF-2alpha, GRP78, and Caspase-3 protein obviously increased (P < 0.01). Expressions of GRP78 and Caspase-3 mRNA significantly increased (P < 0.05, P < 0.01). Compared with the model group, the degrees of the liver injury and the hepatocyte apoptosis in the QGHXR group, the QGR group, and the HXR group were significantly alleviated. The serum tHCY level was significantly lowered. The protein expressions of p-elF-2a, GRP78, and Caspase-3 obviously decreased (P < 0.01). mRNA expressions of GRP78 and Caspase-3 obviously decreased in the QGHXR group (P < 0.05, P < 0.01). Only GRP78 mRNA expression obviously decreased in the QGR group (P < 0.05).

CONCLUSIONQGHXR and its disassembled formulas could attenuate ERS-mediated hepatocyte apoptosis in alcohol-induced liver injury rats by lowering the serum tHCY level and expressions of ERS apoptosis correlated factors.

Animals ; Apoptosis ; drug effects ; Caspase 3 ; metabolism ; Drugs, Chinese Herbal ; administration & dosage ; pharmacology ; therapeutic use ; Endoplasmic Reticulum Stress ; drug effects ; Eukaryotic Initiation Factor-2 ; metabolism ; Heat-Shock Proteins ; metabolism ; Hepatocytes ; drug effects ; pathology ; Homocysteine ; blood ; Liver Diseases, Alcoholic ; blood ; drug therapy ; pathology ; Rats ; Rats, Sprague-Dawley

OBJECTIVETo investigate the role of PERK/eIF2alpha signaling pathway in hepatocyte apoptosis of alcoholic liver injury rats.

METHODSRat models with ethanol-induced liver injury were successfully developed by gastric gavage with ethanol-corn oil mixtures for 12 weeks. At different time points (4, 6, 10, 12 week), liver pathology was dynamically observed. The hepatocyte apoptosis was quantitatively analyzed by Annexin V-FITC/PI double-labeled flow cytometry, the serum total homocysteine (tHCY) level was detected by ELISA and the expressions of eIF2a, p-eIF2a, GRP78/Bip, GRP94, caspase-3 and caspase-12 in liver were examined using Real-time PCR and Western blot.

RESULTSTypical acute liver injury and chronic liver injury were observed at week 4 and week 12 respectively. The hepatocyte apoptosis rates in 6-week model rats significantly increased compared with normal rats (P value less than 0.05), and the degree of hepatocyte apoptosis continued to increase with the modeling time, and the percentages of early and total apoptosis reached 26% and 29% at week 12. From week 6 to week 12, the serum tHCY levels in model rats were obviously higher than in normal rats (P value less than 0.01). Since week 4, eIF2a protein phosphorylation in model rat livers remarkably elevated compared with that in normal rat livers (P value less than 0.01), and at week 12 the peIF2a protein expression in model rat livers increased by 2.81-fold. Since week 4 the expressions of GRP78/Bip, GRP94, caspase-12 and caspase-3 mRNA and protein in model rat livers showed a significant increase as compared to normal rat livers, and at week 12, these gene and protein levels increased 4.70, 12.95, 3.83, 4.05 fold and 3.93, 6.93, 9.88, 3.31 fold, respectively (P value less than 0.01).

CONCLUSIONActivation of PERK/eIF2a signaling pathway contributes to the occurrence and development of hepatocyte apoptosis in alcoholic liver injury rats and it might be as a potential target for therapeutic applications in alcoholic liver diseases.

Animals ; Apoptosis ; Eukaryotic Initiation Factor-2 ; metabolism ; Hepatocytes ; cytology ; pathology ; Liver Diseases, Alcoholic ; metabolism ; pathology ; Male ; Rats ; Rats, Sprague-Dawley ; Signal Transduction ; eIF-2 Kinase ; metabolism

OBJECTIVETo investigate the inhibitory effect of elemene on laryngeal carcinoma (Hep-2 cells) xenograft growth in nude mice and its mechanisms, and to explore the relationship between the expression of eukaryotic initiation factor families (eIF4E & eIF4G) and angiogenesis factors (bFGF & VEGF) after the administration of elemene.

METHODSHuman laryngeal carcinoma cells from Hep-2 cell strain were transplanted subcutaneously to BALB/c-nu/nu nude mice to produce tumors (42 nude mice were separated into seven groups to be treated by intraperitoneal injection). The tumor volume, tumor weight and tumor inhibition rate were evaluated, the expression of eIF4E, eIF4G, bFGF, VEGF and microvessel density were estimated by paraffin-embedded sections of seven groups' tumor samples analyzed utilizing immunohistochemical streptavidin peroxidase technique.

RESULTSElemene could inhibit the tumor growth in vivo. A significant suppression of tumor growth was observed when the dosage was increased. The tumor inhibition rates (IR) of elemene 50 mg/kg, 100 mg/kg and 200 mg/kg treated group were 5.2% , 41.7% and 50. 5% respectively. The IR of 100 mg/kg elemene (41.7%) was not significantly different with that of 3 mg/kg cisplatin (44.6%), and the IR of the drug combination (100 mg/kg elemene + 3 mg/kg cisplatin) was 51.2%. Compared with control groups the protein expression of eIF4E, eIF4G, bFGF and VEGF were significantly inhibited by elemene (P < 0.05), and the microvessel density in elemene treated groups decreased (P < 0.05). The tumor inhibition rate of combined elemene 100 mg/kg and cisplatin 3 mg/kg was 51.2%.

CONCLUSIONSElemene could inhibit the subcutaneous plantation of human laryngeal carcinoma in nude mice and its mechanism may be associated with inhibited expression of eIF families and angiogenesis factors. The combination of elemene and cisplatin could promote the synergistic effect on chemotherapy in the target tumor cells.

Animals ; Carcinoma, Squamous Cell ; blood supply ; pathology ; Cell Line, Tumor ; Cisplatin ; pharmacology ; Eukaryotic Initiation Factor-4E ; metabolism ; Eukaryotic Initiation Factor-4G ; metabolism ; Fibroblast Growth Factor 2 ; metabolism ; Humans ; Laryngeal Neoplasms ; blood supply ; pathology ; Mice ; Mice, Inbred BALB C ; Mice, Nude ; Neoplasm Transplantation ; Neovascularization, Pathologic ; Sesquiterpenes ; pharmacology ; Vascular Endothelial Growth Factor A ; metabolism ; Xenograft Model Antitumor Assays